Salmonella

Epidemiol Infect, 2004 Oct, 132(5), 889 - 95
Outbreak of Salmonella Livingstone infection in Norway and Sweden due to contaminated processed fish products; Guerin PJ et al.; In Europe, the number of reported sporadic human cases of Salmonella Livingstone infection is low, and outbreaks are rare . We report the largest S . Livingstone outbreak described in the literature having an identified source of infection . In February 2001, an increased incidence of infection caused by S . Livingstone was observed in Norway and Sweden . By July 2001, 44 cases were notified in Norway and 16 in Sweden . The median age was 63 years, and 40 were women . There were three deaths, and 22 patients were hospitalized . Based on standardized questionnaires and retrospective studies of S . Livingstone strains in Norway and Sweden, food items with egg powder were suspected, and S . Livingstone was subsequently recovered from a processed fish product at the retail level . Analysis by pulsed-field gel electrophoresis documented that isolates from the fish product belonged to the same clone as the outbreak strain.

Epidemiol Infect, 2004 Oct, 132(5), 881 - 7
Outbreak of Salmonella Goldcoast infections linked to consumption of fermented sausage, Germany 2001; Bremer V et al.; Salmonella Goldcoast (SGC), an uncommon serotype in Germany, was identified in 25 isolates between 1 April and 7 May 2001 . To determine the cause of the outbreak, we conducted a matched case-control study including 24 cases and 51 controls . In a multivariable regression model, only consumption of a raw fermented sausage manufactured by a local company remained significant (adjusted odds ratio 20.0, 95 % confidence interval 2.7-302.5) . SGC isolated from case-patients shared an indistinguishable pulsed-field gel electrophoresis pattern . A part of the produced raw fermented sausage was sold after only 4 days of fermentation . Samples from the premises and products of the company were negative for SGC . However, short-time raw fermented sausage is more likely to contain pathogens . Irradiation of raw ingredients is not accepted by German consumers, thus strict adherence to good manufacturing practices, the use of HACCP programmes as well as on-farm programmes remain crucial to reduce Salmonella.

Epidemiol Infect, 2004 Oct, 132(5), 873 - 9
Salmonella Enteritidis outbreak associated with a school-lunch dessert: cross-contamination and a long incubation period, Japan, 2001; Matsui T et al.; A Salmonella Enteritidis (SE) outbreak in Japan was investigated with an observational study, analytical epidemiology and bacteriological examination (including phage typing) . The outbreak occurred among 96 schoolchildren, and was caused by SE phage type 1 . The outbreak source was dessert buns served at a school lunch (RR 42.55, 95 % CI 5.93-305.11, P < 0.001) . The buns were probably cross-contaminated from eggs from a factory with a history of SE-contaminated products . The incubation period was longer than usual (3-16 days, median 8 days) . A low contaminating dose may account for the long incubation period and low attack rate . Outbreak detection was hampered by the absence of routine Salmonella surveillance in Japan . The investigation was complicated by concurrent illnesses from other SE phage types . It was successful, in part, because adequate food samples were available for microbiological testing.

J Clin Microbiol, 2004 Oct, 42(10), 4885 - 8
Pediatric infection due to multiresistant Salmonella enterica serotype Infantis in Honduras; Liebana E et al.; We report the case of a pediatric patient with a Salmonella enterica serotype Infantis infection . Detailed microbiological investigation revealed that this isolate carries four beta-lactamase genes (bla(TEM-1b) variant, bla(SHV-5), bla(CTX-M-15), and bla(CMY-2)) conferring resistance to all beta-lactams but imipenem . This is the first report of a Salmonella isolate with CTX-M and AmpC enzymes on the American continent, the first report of bla(CMY-2) in Salmonella serotype Infantis, and the first report of bla(CTX-M-15) in the genus Salmonella.

J Clin Microbiol, 2004 Oct, 42(10), 4843 - 5
Fluorescent amplified fragment length polymorphism subtyping of multiresistant Salmonella enterica serovar Typhimurium DT104; Lawson AJ et al.; Fluorescent amplified fragment length polymorphism (FAFLP) subtyping analysis was used to genotype multiresistant Salmonella enterica serovar Typhimurium definitive phage type 104 . Thirteen distinct FAFLP profiles were found among 85 isolates exhibiting identical pulsed-field gel electrophoresis (PFGE) profiles . A single FAFLP profile was shared by 93% of outbreak-associated isolates and 82% of sporadic isolates . This study demonstrates the value of FAFLP as a high-resolution tool for epidemiological investigation of Salmonella.

J Clin Microbiol, 2004 Oct, 42(10), 4821 - 3
Rapid and economical method for biochemical screening of stool isolates for Salmonella and Shigella species; Wilson G; The LOUIS test is a screening protocol for Salmonella and Shigella that uses rapid enzyme tests . It had a sensitivity of 100% and a specificity of 94% and achieved presumptive reporting of Salmonella 3 h after colony isolation with savings of time and money compared to commercial identification systems.

Indian J Pathol Microbiol, 2004 Jan, 47(1), 76 - 7
Infective endocarditis due to Salmonella typhi--a case report; Wani T et al.; Endocarditis is a rare complication of typhoid fever . We report a case in which Salmonella enterica serotype typhi was isolated from a case of endocarditis . The isolate was resistant to ampicillin, chloramphenicol and ciprofloxacin but sensitive to ceftriaxone, amikacin and gentamicin.

Indian J Pathol Microbiol, 2004 Jan, 47(1), 75 - 6
Pleural empyema due to S . typhi: a case report; Mishra S et al.; In a 35 year old immunocompetent male, clinically diagnosed as a case of hydropneumothorax of left side, Salmonella typhi was isolated as the causative agent of pleural empyema.

Mol Microbiol, 2004 Oct, 54(2), 386 - 95
Activation of the RcsC/YojN/RcsB phosphorelay system attenuates Salmonella virulence; Mouslim C et al.; Bacterial pathogens have the ability to sense their presence in host tissues and to promote expression of their virulence factors in a time- and location-dependent manner . However, little is known about those genes whose expression is detrimental and thus suppressed during infection . Here we report that constitutive activation of the RcsC/YojN/RcsB system resulting from a mutation in the rcsC sensor gene dramatically attenuates Salmonella virulence . Mutation of the cognate response regulator gene rcsB restored full virulence to the rcsC constitutive mutant, indicating that virulence attenuation results from aberrant expression of RcsB-regulated genes . The virulence attenuation phenotype was partially dependent on the regulatory gene rcsA, which is necessary for transcription of certain RcsB-regulated genes, and on the RcsB- and RcsA-dependent colanic acid capsule synthesis cps operon . The rcsC constitutive mutant was phagocytized less efficiently by macrophages and it was defective for invasion of non-phagocytic cells and survival within macrophages; but it could protect mice upon challenge with wild-type Salmonella . Our results suggest that a successful infection demands that pathogens turn off expression of products that might interfere with virulence functions.

Mol Microbiol, 2004 Oct, 54(2), 287 - 90
Modulation of AraC family member activity by protein ligands; Plano GV; A number of AraC family transcriptional activators bind low-molecular-weight ligands that modulate the activity of these proteins . Recently, it has become clear that the activity of several virulence-related AraC family members is regulated through the direct interaction of protein ligands . These interactions, in general, function to activate or repress the transcription of virulence genes in response to specific extracellular stimuli . The identification and characterization of several protein ligands that modify the activity of AraC family members in Pseudomonas aeruginosa and Salmonella enterica are discussed herein.

Cell Microbiol, 2004 Nov, 6(11), 1071 - 84
Salmonella enterica serovar Typhimurium interaction with dendritic cells: impact of the sifA gene; Petrovska L et al.; Salmonella enterica serovar Typhimurium (S . Typhimurium) and several mutant derivatives were able to enter efficiently murine bone marrow-derived dendritic cells using mechanisms predominantly independent of the Salmonella pathogenicity island 1 type III secretion system . The levels of intracellular bacteria did not increase significantly over many hours after invasion . Using fluid endocytic tracers and other markers, S . Typhimurium-containing vacuoles (SCVs) were physically distinguishable from early endocytic compartments . Fifty to eighty per cent of SCVs harbouring wild-type S . Typhimurium or aroA, invH and ssaV mutant derivatives were associated with late endosome markers . In contrast, S . Typhimurium sifA was shown to escape the SCVs into the cytosol of infected dendritic cells . S . Typhimurium aroC sifA was more efficient than S . Typhimurium aroC in delivering a eukaryotic promoter-driven green fluorescent protein reporter gene for expression in dendritic cells . In contrast, S . Typhimurium aroC sifA did not detectably increase the efficiency of MHC class I presentation of the model antigen ovalbumin to T cells compared to a similar aroC derivative . Mice infected with the S . Typhimurium aroC sifA expressing ovalbumin did not develop detectably enhanced levels of cytotoxic T cell or interferon-gamma production compared to S . Typhimurium aroC derivatives.

Cell Microbiol, 2004 Nov, 6(11), 1041 - 55
Analysis of the mechanisms of Salmonella-induced actin assembly during invasion of host cells and intracellular replication; Unsworth KE et al.; Salmonella enterica serovar Typhimurium (S . typhimurium) induces actin assembly both during invasion of host cells and during the course of intracellular bacterial replication . In this study, we investigated the involvement in these processes of host cell signalling pathways that are frequently utilized by bacterial pathogens to manipulate the eukaryotic actin cytoskeleton . We confirmed that Cdc42, Rac, and Arp3 are involved in S . typhimurium invasion of HeLa cells, and found that N-WASP and Scar/WAVE also play a role in this process . However, we found no evidence for the involvement of these proteins in actin assembly during intracellular replication . Cortactin was recruited by Salmonella during both invasion and intracellular replication . However, RNA interference directed against cortactin did not inhibit either invasion or intracellular actin assembly, although it resulted in increased cell spreading and a greater number of lamellipodia . We also found no role for either the GTPase dynamin or the formin family member mDia1 in actin assembly by intracellular bacteria . Collectively, these data provide evidence that signalling pathways leading to Arp2/3-dependent actin nucleation play an important role in S . typhimurium invasion, but are not involved in intracellular Salmonella-induced actin assembly, and suggest that actin assembly by intracellular S . typhimurium may proceed by a novel mechanism.

Cell Microbiol, 2004 Nov, 6(11), 1019 - 25
Salmonella-induced macrophage death: multiple mechanisms, different outcomes; Hueffer K et al.; The facultative intracellular pathogen Salmonella enterica triggers programmed cell death in macrophages . The close examination of this phenomenon has revealed an unusually complex picture involving diverse mechanisms that lead to different types of programmed cell death . It appears that the outcome of the interaction of salmonella with macrophages depends on the relative contribution of two type III protein secretion systems, in conjunction with the stimulation of innate immunity outputs through conserved determinants collectively known as 'pathogen-associated molecular patterns' (PAMPs) . These interactions result in a breakdown of the balance between survival and pro-apoptotic cellular pathways, which eventually leads to macrophage cell death . The relative significance for the infection process of the different types of macrophage cell death triggered by salmonella remains to be established.

Dtsch Tierarztl Wochenschr, 2004 Aug, 111(8), 331 - 4
Risk assessment strategies for Europe: integrated safety strategy or final product control: Example of Listeria monocytogenes in processed products from pork meat industry; Salvat G et al.; The European regulation 2160/2003 of November 17th, 2003 clearly shows the European strategy of zoonosis monitoring and control as an integrated approach, including the entire food production chain with a first application to Salmonella control in different animal species . This regulation is the consequence of a risk assessment performed with a "farm to fork" philosophy . European strategy is scarcely different from the American strategy, despite the fact that both were achieved by a quantitative risk assessment, as for instance, in the USA the control of Salmonella in eggs is supposed to be completed by refrigeration . Nevertheless, the EU will still have a final product control approach towards future regulations on microbiological criteria for foodstuffs . The final production monitoring and control with HACCP (93/43/EC) and microbiological criteria is the only one available for L . monocytogenes in foodstuffs . The purpose of this paper is to discuss alternative control strategies for L . monocytogenes in pig production including integrated risk assessment . In France, most of the food-borne outbreaks associated with L . monocytogenes in delicatessen were due to one particular group of strains belonging to serovar 4b and presenting a particular RFLP/PFGE (Restriction Fragment Length Polymorphism/Pulsed Field Gel Electrophoresis) profile . The outbreak itself is always associated with the initial contamination of a RTE ("ready to eat") product and re-contamination by inappropriate handling after cooking . Consequently, in most cases the RTE product is subject to inadequate refrigeration during an excessive shelf-life . The responsibility of the food industry and the consumer is clearly engaged during this scenario of foodborne diseases . The question is how to avoid the introduction of this particular strain of L . monocytogenes in the food chain . In a study we tried to evaluate the risk of pig carcass contamination at slaughterhouse level and to identify the main risk factors associated with the infection of live pigs . In most cases inappropriate cleaning and disinfection of surfaces were associated with the contamination of raw meat, but in some cases the introduction of epidemic strains in the food chain was also associated with primary production . Feeding with soup in piggeries seemed to select a particular microbial ecology associated to L . monocytogenes contamination of live pigs . The possible strategies that may be used to control L . monocytogenes in live pig production are not yet developed sufficiently to be included in the EC regulation but should be discussed in more detail.

Dtsch Tierarztl Wochenschr, 2004 Aug, 111(8), 324 - 6
{Up-to-date information from the German QS salmonella monitoring and reduction programme}; Blaha T; In the beginning, the history, objectives and basic principles of the samonella monitoring and reduction programme that has been developed and implemented since 2002 in the framework of the German cross-sectional quality management and assurance programme "QS" for the food chain are expained in detail . It is a semi-quantitative assessment of the intra-herd prevalence of animals (60 samples per slaughter pig herd and year) with antibodies against salmonella species . By means of this asessment, herds are assigned to one of three risk categories (I = low risk, II = medium risk, and III = high risk) in terms of the probability to introduce Salmonella spp . into the food chain via slaughter pigs . The assignment to the categories is the basis of salmonella-reducing intervention measures . The implementation of the programme is considerably behind the schedule by mid-2004 . The reasons for the delay are explained and conclusions for the further development of the programme are drawn.

J Gene Med, 2004 Dec, 6(12), 1382 - 93
Endostatin gene therapy delivered by Salmonella choleraesuis in murine tumor models; Lee CH et al.; BACKGROUND: Some anaerobic and facultatively anaerobic bacteria have been used experimentally as anticancer agents because of their selective growth in tumors . In this study, we exploited attenuated Salmonella choleraesuis as a tumoricidal agent and a vector to deliver the endostatin gene for tumor-targeted gene therapy . METHODS: Attenuated S . choleraesuis carrying a eukaryotic expression plasmid encoding reporter gene was used to evaluate its abilities of tumor targeting and gene delivery in three syngeneic murine tumor models . Furthermore, S . choleraesuis carrying the endostatin expression vector was administered intraperitoneally into tumor-bearing mice, and its antitumor effect was evaluated . RESULTS: Systemically administered S . choleraesuis preferentially accumulated within tumors for at least 10 days, forming tumor-to-normal tissue ratios exceeding 1000-10 000 : 1 . Transgene expression via S . choleraesuis-mediated gene transfer also persisted for at least 10 days . Host immune responses and tumor hypoxia may influence tumor-targeting potential of S . choleraesuis . When systemically administered into mice bearing melanomas or bladder tumors, S . choleraesuis carrying the endostatin expression vector significantly inhibited tumor growth by 40-70% and prolonged survival of the mice . Furthermore, immunohistochemical studies in the tumors revealed decreased intratumoral microvessel density, reduced expression of vascular endothelial growth factor (VEGF), and increased infiltration of CD8(+) T cells . CONCLUSIONS: These results suggest that tumor-targeted gene therapy using S . choleraesuis carrying the endostatin expression vector, which exerts tumoricidal and antiangiogenic activities, represents a promising strategy for the treatment of solid tumors . Copyright (c) 2004 John Wiley & Sons, Ltd.

J Bacteriol, 2004 Oct, 186(20), 6885 - 90
A pH-sensitive function and phenotype: evidence that EutH facilitates diffusion of uncharged ethanolamine in Salmonella enterica; Penrod JT et al.; The eutH gene is part of an operon that allows Salmonella enterica to use ethanolamine as a sole source of nitrogen, carbon, and energy . Although the sequence of EutH suggests a role in transport, eutH mutants use ethanolamine normally under standard conditions (pH 7.0) . These mutants fail to use ethanolamine at a low pH . Evidence is presented that protonated ethanolamine (Eth0) does not enter cells, while uncharged ethanolamine (Eth0) diffuses freely across the membrane . The external concentration of Eth0 varies with the pH (pK=9.5) . At pH 7.0, the standard ethanolamine concentration (41 mM) provides enough Eth0 for an influx rate that can support growth with or without EutH . When a lowered pH and/or ethanolamine concentration reduced the Eth0 concentration below 25 microM, EutH was needed to facilitate diffusion . EutH+ cells grew normally at Eth0 concentrations above 3 microM, close to the Km (9 microM) of the first degradative enzyme, ethanolamine ammonia lyase . It is suggested that EutH facilitates diffusion of Eth0 . As predicted for a transporter, EutH contributed to the toxicity of ethanolamine seen under some conditions; furthermore, fusion of EutH to fluorescent Yfp protein provided evidence that EutH is a membrane protein.

J Wildl Dis, 2004 Jul, 40(3), 566 - 70
A comparison of Salmonella serotypes isolated from New Zealand sea lions and feral pigs on the Auckland Islands by pulsed-field gel electrophoresis; Fenwick SG et al.; The Salmonella serotypes S . Cerro and S . Newport were isolated from New Zealand sea lions (Phocarctos hookeri) and feral pigs on the Auckland Islands in the New Zealand subantarctic region . The isolates were typed by pulsed-field gel electrophoresis using Xba1 as the restriction enzyme . The isolates were indistinguishable, which suggests that Salmonella infection cycles between sea lions and pigs in this environment . Apart from a previous isolation from a single New Zealand fur seal (Arctocephalus forsteri), S . Newport has not been recorded in any animals from New Zealand, but it is associated with gastroenteritis in humans . Contamination of the marine environment by human waste is a possible source of infection for marine mammals and warrants further investigation.

Toxicol In Vitro, 2004 Dec, 18(6), 895 - 900
Mutagenic activity in waste from an aluminum products factory in Salmonella/microsome assay; Varella SD et al.; The mutagenic activity of waste material originating from an aluminum products factory was determined by the Salmonella/microsome assay, using the bacterial strains TA100, TA98 and YG1024 . The material was obtained by sweeping the factory floor at the end of the work shift . Organic compounds were extracted by ultrasound for 30 min in dichloromethane or 70% ethanol . After evaporation of solvent, these extracts were dissolved in dimethylsulfoxide, and tested for the mutagenic activity at varying concentrations . All the extracts from the factory had mutagenic activity, especially in the YG1024 strain, suggesting the presence of aromatic amines, later confirmed by chemical analysis . The TA98 strain also showed mutagenic activity, though it did not exhibit the highest mutagenicity index observed with the YG1024 strain . In TA100, mutagenic activity was not observed . This study should serve as an alert to management and those who are occupationally exposed, and as a warning that this type of waste should not be discarded in the environment without any control.

J Psychosom Res, 2004 Aug, 57(2), 189 - 94
Mild acute inflammatory stimulation induces transient negative mood; Strike PC et al.; OBJECTIVE: This study aims to assess the mood changes induced by mild acute inflammatory stimulation (typhoid vaccination) . METHODS: Using a double blind study design, 26 healthy volunteers underwent baseline assessments of mood, financial strain and work stress and were randomised to injection of Salmonella typhi vaccine or placebo injection . Mood, symptoms and body temperature was assessed by a modified version of the Profile of Mood States at 1, 2, 3, 4, 6 and 8 h post injection . RESULTS: Typhoid vaccination induces no increases in physical symptoms or temperature . Mood improved over the day in the placebo but not in the vaccine condition . Negative changes in mood following injection were correlated with chronic stress (financial strain) in the vaccination condition (r=-.65, P<.025) . CONCLUSION: A mild acute inflammatory stimulus induces transient negative mood, and responses were modulated by chronic stress . Implications for depressed mood in physical illness are discussed.

Parasitol Today, 1991 Mar, 7(3), 42 - 5
Genetic control of innate resistance to mycobacterial infections; Schurr E et al.; The Mendelian segregation of resistance to infection in different strains of mice infected with mycobacteria, Salmonella and Leishmania spp, all of which live in macrophages, is currently under close scrutiny . Here, Erwin Schurr and colleagues review the nature and function of the Bcg gene in controlling innate resistance to mycobacterial infection in mice and speculate on the occurrence of a possible human equivalent.

Parasitol Today, 1989 Feb, 5(2), 41 - 6
Adjuvants for anti-parasite vaccines; Bomford R; To date the most successful human vaccines use attenuated living pathogens, but the advent of techniques in genetic engineering has meant that pure antigen can be provided in quantity . This has allowed the development of combined vaccines that use only the parasite antigens that convey protective immunity . However, isolated antigens lose immunogenicity so to regain potency, living attenuated carriers like Vaccinia or Salmonella can be used . To avoid the attendant drawbacks of carriers as immunopotentiating agents, adjuvants are under investigation as alternatives for use in vaccines against parasitic infections . In this review, Robert Bomford describes the adjuvants currently being examined for use in vaccines for both protozoan and helminth infections including Leishmania, malaria and Schistosoma . He also points out the drawbacks of using adjuvants and the dilemma of needing to stimulate cell'-mediated immunity while avoiding the immunopathological consequences of doing so.

Acta Clin Belg, 2004 May-Jun, 59(3), 152 - 60
Antimicrobial drug resistance in nontyphoid human Salmonella in Belgium: trends for the period 2000-2002; Wybot I et al.; In order to assess antimicrobial resistance in nontyphoid human Salmonella in Belgium, the six most important serovars, representing together more than 90% of laboratory confirmed cases, were randomly sampled . From June 2000 until December 2002, a total of 1756 isolates were screened for their antimicrobial resistance profile by the disc diffusion method . S . Hadar strains showed the highest level of antimicrobial resistance . Simultaneous resistance to ampicillin, nalidixic acid, tetracycline and streptomycin was observed in 81.5, 58 and 76.1% of these isolates in 2000, 2001 and 2002, respectively . All S . Hadar isolates resistant to nalidixic acid also displayed decreased susceptibility to ciprofloxacin (MIC50 values of 0.25 microg/mL in 2000-2001 and 0.19 microg/mL in 2002) . In 2000, 2001 and 2002, respectively 44.6, 46 and 36.5% of S . Typhimurium isolates were multiresistant (resistant to 4 or more antimicrobial agents) . These multiresistant isolates were preferably associated with a few phage types, such as DT104 . Complete resistance to ciprofloxacin was detected in three S . Typhimurium isolates and sequencing of the gyrA gene revealed for each isolate two mutations at codons corresponding to Ser-83 and Asp-87 . Multiresistance was also common in S . Virchow (7.7%, 15.9% and 29.7%, in 2000, 2001 and 2002, respectively) . Resistance to nalidixic acid in S . Virchow isolates increased from 46.2% in 2000 to 80.9% in 2002 and six S . Virchow isolates were detected as cefotaxime resistant . In contrast, the vast majority of S . Enteritidis, S . Brandenburg and S . Derby isolates remained sensitive to almost all antimicrobial agents tested.

Bull Soc Pathol Exot, 2004 Aug, 97(3), 173 - 4
{Contribution of phage typing and ribotyping in investigating a typhoid fever outbreak in Tunisia}; Bouallegue O et al.; A study was carried out to investigate an outbreak of typhoid fever that occurred in Sousse city and in the vicinity of Sousse (Tunisia) during summer 1999 . Twenty four isolates of Salmonella enterica serotype Typhi were isolated in hospitalized patients with a typhoid fever in two hospitals (Farhat Hached Sousse and M'saken) and were studied with the help of two molecular typing methods: phage typing and automated ribotyping . Twenty one isolates with the Vi antigen had profile DVS (Degraded Vi Strain), one isolate with the Vi antigen belonged to phage type A and two isolates were non phage typable (no Vi antigen) . The same ribotype was found in 22 out of 24 isolates . The results suggested that ribotyping is more discriminative than phage typing in this case in distinguishing strains and the strains shared the same source of the contamination . Unfortunately the precise source of the contamination could not be determined.

Commun Dis Intell, 2004, 28(2), 207 - 10
OzFoodNet: enhancing foodborne disease surveillance across Australia: quarterly report, January to March 2004; Crystal structure of an aminoimidazole riboside kinase from Salmonella enterica: implications for the evolution of the ribokinase superfamily; Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USAThe crystal structures of a Salmonella enterica aminoimidazole riboside (AIRs) kinase, its complex with the substrate AIRs, and its complex with AIRs and an ATP analog were determined at 2.6 angstroms, 2.9 angstroms, and 2.7 angstroms, respectively . The product of the Salmonella-specific gene stm4066, AIRs kinase, is a homodimer with one active site per monomer . The core structure, consisting of an eight-stranded beta sheet flanked by eight alpha helices, indicates that AIRs kinase is a member of the ribokinase superfamily . Unlike ribokinase and adenosine kinase in this superfamily, AIRs kinase does not show significant conformational changes upon substrate binding . The active site is covered by a lid formed by residues 16-28 and 86-100 . A comparison of the structure of AIRs kinase with other ribokinase superfamily members suggests that the active site lid and conformational changes that occur upon substrate binding may be advanced features in the evolution of the ribokinase superfamily .

J Am Vet Med Assoc, 2004 Sep 1, 225(5), 722 - 5, 699
Myonecrosis and cutaneous infarction associated with Salmonella serovar Infantum infection in a horse; Pellegrini-Masini A et al.; A 5-year-old Quarter Horse mare was referred for evaluation of oral ulcers, limb edema, weight loss, and weakness . There was marked diffuse swelling extending from the stifle region to the tarsal region of the left hind limb, and the horse had a left hind limb lameness . Firm swellings ranging from 2 to 15 cm in diameter and consisting of nodules, plaques, and discrete masses were palpated on both sides of the neck, over the right shoulder region, over the left elbow region, and over the left caudoventral aspect of the abdomen . Laboratory abnormalities included hypoproteinemia, neutrophilia, and hyperfibrinogenemia . Results of ultrasonographic examination of the left hind limb and masses were suggestive of muscle edema, necrosis, and hemorrhage . Histologic examination of a biopsy specimen from a subcutaneous mass revealed necrotizing, suppurative myositis . The horse's condition gradually deteriorated, and the horse was euthanatized . Necropsy revealed myonecrosis, cutaneous infarcts, hepatic abscesses, and cholangitis . Salmonella serovar Infantum was cultured from liver and muscle lesions, and a diagnosis of Salmonella myonecrosis was made.

Mamm Genome, 2004 Aug, 15(8), 630 - 6
Quantitative trait loci in Chromosomes 3, 8, and 9 regulate antibody production against Salmonella flagellar antigens in the mouse; de Souza CM et al.; Two mouse lines were produced by bidirectional selection according to the high (HIII) or low (LIII) antibody responsiveness against Salmonella flagellar antigens (Selection III) . In the present work we conducted a genomewide scan to map the quantitative trait loci (QTL) involved in the antibody response regulation in these selected mice . HIII and LIII genomes were screened with microsatellite markers and those found polymorphic between the lines (146) were used for linkage analysis in F2 (HIII x LIII) intercross . Simple interval mapping analysis was performed using Mapmanager QTX software . Three highly significant QTL linked to antibody production against Salmonella flagellar antigens have been demonstrated in Chromosomes 3, 8, and 9 . HIII and LIII lines differ in the resistance to several diseases, therefore, the relevance of these QTL with the genetic factors involved in infections, autoimmunity, and neoplastic disease progression is discussed.

Ned Tijdschr Geneeskd, 2004 Aug 14, 148(33), 1636 - 41
{Subcutaneous nodules with malignant presentation, but caused by infection}; Hermans SM et al.; Three patients, a woman aged 32, a boy aged 6.5 and a man aged 56 years, presented with a subcutaneous mass suggesting a malignancy: respectively a rubbery swelling, painful to the touch below the left scapula, a partly massive, partly soft swelling on the inside of the left upper leg, and a non-fluctuating mass near the right eighth rib, parasternally . Additional diagnostic investigation revealed an infectious cause: respectively Mycobacterium tuberculosis, Bartonella henselae and Salmonella typhi . Antimicrobial therapy was successful . Subcutaneous masses suspected of being a benign or malignant tumour are sometimes caused by an infection . The differential diagnosis is extensive . Sometimes the travel anamnesis yields helpful information . It is concluded that besides histopathological examination, microbiological investigation can play a major role in the evaluation of subcutaneous masses.

Prev Vet Med, 2004 Aug 30, 65(1-2), 63 - 75
Risk factors for the herd-level bacteriologic prevalence of Salmonella in Belgian slaughter pigs; Nollet N et al.; Herd-level risk factors for salmonellosis in pigs were investigated in a cross-sectional study on 62 Belgian farrow-to-finish pig herds belonging to one slaughterhouse cooperative . Data concerning housing and ventilation, management, hygiene, biosecurity, production parameters, feeding, disease control and transport to the slaughterhouse were collected during a herd visit by means of a questionnaire . The percentage of positive animals in a slaughterhouse delivery, as determined by qualitative Salmonella isolation in the mesenteric lymph nodes taken from 30 slaughter pigs, was the outcome variable . All samples were taken in 4 different slaughterhouses . Variables first were submitted to a univariable analysis using a logistic mixed regression model, with herd as random effect . Variables which were related to the Salmonella prevalence (P < 0.05) were analysed further in a multivariable model . The clustering of Salmonella infection within a pen also was studied in a generalised mixed model with pen as random effect . Salmonella isolates were identified by serotype . In 57 (92%) of the herds, at least one sample was found positive for Salmonella . The median percentage of positive Salmonella samples per delivery was 64% (range: 0-100%) . In the multivariable model, only type of floor was related significantly to the prevalence: 100% (95% CI 88-100) for herds with <50% slatted floors to 54% (36-70) for herds with fully slatted floors . The results from the analysis should be interpreted with care because only 62 herds were included in the study . Clustering between pigs from the same pen could not be demonstrated (variance +/- S.D.: 0.11 +/- 0.16) . S . typhimurium (30%) and S . derby (20%) were most common among the 23 different serotypes that were found.

Prev Vet Med, 2004 Aug 30, 65(1-2), 31 - 46
Predicted quantitative effect of logistic slaughter on microbial prevalence; Evers EG; Logistic slaughter is an intervention measure intended to reduce cross-contamination during slaughter by slaughtering contaminated units (=(groups of) animals) last . This paper describes a simple mathematical model which predicts the prevalences of contaminated units after logistic and random-order slaughter . The effect of logistic slaughter is the difference between these prevalences . The model assumes that uncontaminated units can become contaminated by contaminated units that were slaughtered before them; the contributions of contaminated units are independent . It also assumes that a slaughterhouse is uncontaminated at the start of the day and that a unit that is contaminated before slaughter also is contaminated after slaughter . The model was analysed using numerical simulations; for a selection of cases, analytical formulas can be derived and are presented . Contamination of broiler flocks with Salmonella was used as a case study . Even for this simple model, data availability is a problem leading to uncertain parameter estimates . An average cross-contamination scenario predicts that the beneficial effect of logistic slaughter is as low as 9.1%, which casts doubt on its usefulness as an intervention measure . The case study produced these general model results: the effect of logistic slaughter increases with the probability of cross-contamination between units; with the length of the slaughter queue; and with sensitivity (the probability of a positive test from a unit contaminated at the start of slaughter) . However, the effect is small if the prevalence of contaminated units before slaughter is low or high.

J Food Prot, 2004 Sep, 67(9), 2024 - 32
Archiving of food samples from restaurants and caterers--quantitative profiling of outbreaks of foodborne salmonellosis in Japan; Kasuga F et al.; The Ministry of Health, Labor and Welfare (former MHW) of Japan issued a Directive in 1997 advising restaurants and caterers to freeze portions of both raw food and cooked dishes for at least 2 weeks . This system has been useful for determining vehicle foods at outbreaks . Enumeration of bacteria in samples of stored food provide data about pathogen concentrations in the implicated food . Data on Salmonella concentrations in vehicle foods associated with salmonellosis outbreaks were collected in Japan between 1989 and 1998 . The 39 outbreaks that occurred during this period were categorized by the settings where the outbreaks took place, and epidemiological data from each outbreak were summarized . Characteristics of outbreak groups were analyzed and compared . The effect of new food-storage system on determination of bacterial concentration was evaluated . Freezing and nonfreezing conditions prior to microbial examination were compared in the dose-response relationship . Data from outbreaks in which implicated foods had been kept frozen suggested apparent correlation between the Salmonella dose ingested and the disease rate . Combined with results of epidemiological investigation, quantitative data from the ingested pathogen could provide complete dose-response data sets.

J Food Prot, 2004 Sep, 67(9), 2000 - 7
An epidemiologic critique of current microbial risk assessment practices: the importance of prevalence and test accuracy data; Gardner IA; Data deficiencies are impeding the development and validation of microbial risk assessment models . One such deficiency is the failure to adjust test-based (apparent) prevalence estimates to true prevalence estimates by correcting for the imperfect accuracy of tests that are used . Such adjustments will facilitate comparability of data from different populations and from the same population over time as tests change and the unbiased quantification of effects of mitigation strategies . True prevalence can be estimated from apparent prevalence using frequentist and Bayesian methods, but the latter are more flexible and can incorporate uncertainty in test accuracy and prior prevalence data . Both approaches can be used for single or multiple populations, but the Bayesian approach can better deal with clustered data, inferences for rare events, and uncertainty in multiple variables . Examples of prevalence inferences based on results of Salmonella culture are presented . The opportunity to adjust test-based prevalence estimates is predicated on the availability of sensitivity and specificity estimates . These estimates can be obtained from studies using archived gold standard (reference) samples, by screening with the new test and follow-up of test-positive and test-negative samples with a gold standard test, and by use of latent class methods, which make no assumptions about the true status of each sampling unit . Latent class analysis can be done with maximum likelihood and Bayesian methods, and an example of their use in the evaluation of tests for Toxoplasma gondii in pigs is presented . Guidelines are proposed for more transparent incorporation of test data into microbial risk assessments.

J Food Prot, 2004 Sep, 67(9), 1953 - 6
Antibacterial effect of water-soluble arrowroot (Puerariae radix) tea extracts on foodborne pathogens in ground beef and mushroom soup; Kim S et al.; Antimicrobial activity of water-soluble arrowroot tea extract was evaluated against Escherichia coli O157:H7, Salmonella enterica Serotype Enteritidis, Listeria monocytogenes, and Staphylococcus aureus in ground beef and mushroom soup . The concentrations of arrowroot tea used were 0, 3, and 6% (wt/wt) for ground beef and 0, 1, 5, and 10% (wt/vol) for mushroom soup . Samples without tea extract were considered controls . Each sample was stored for 0, 1, 3, 5, and 7 days at 7 degrees C for ground beef and for 0, 1, 3, and 5 days at 35 degrees C for mushroom soup . On each sampling time, proper dilutions were spread plated on each pathogen-specific agar . Viable cell counts of each pathogen were performed after incubation at 35 degrees C for 24 to 48 h . For ground beef, Salmonella Enteritidis and L . monocytogenes were slightly suppressed by approximately 1.5 log, compared with the control, on day 7 at 3 and 6% arrowroot tea treatment . For mushroom soup, all test pathogens were suppressed by 6.5, 4.7, 3.4, and 4.3 log at 5% and 6.0, 4.7, 5.0, and 4.3 log at 10% against E . coli O157:H7, Salmonella Enteritidis, L . monocytogenes, and S . aureus, respectively, compared with the control on day 5 . Mushroom soup with 1% arrowroot tea also showed 2.3- and 2.7-log growth suppression of Salmonella Enteritidis and S . aureus, respectively, compared with the control on day 5 . This study showed that the use of arrowroot tea would effectively inhibit the microbial growth of both gram-negative and gram-positive foodborne pathogens in various foods, especially liquid foods.

J Food Prot, 2004 Sep, 67(9), 1886 - 91
Effect of thermoultrasonication on Salmonella enterica serovar Enteritidis in distilled water and intact shell eggs; Cabeza MC et al.; The combined effects of simultaneous application of ultrasonic waves and heat treatment (thermoultrasonication) on the survival of a strain of Salmonella enterica Enteritidis was studied in both distilled water and intentionally contaminated intact eggs immersed in water . Although minor differences were observed between parameters obtained for thermoultrasonic treatment of bacteria suspended in water and those attached to the shell egg, the thermoultrasonication effects were considered to be of the same level in the range of temperatures assayed (52 to 58 degrees C) . This combined process presented a clearly higher killing effect than the heat treatment alone . It decreased the decimal reduction times (D-values) by 80 to 55%, respectively, in the range of temperatures for heat treatment when the organism was suspended in water, which means a 99.5% reduction (5D to >2D) of the original bacterial load versus a 90% reduction for the heat treatment alone . The practical implications of the phenomenon are discussed.

J Food Prot, 2004 Sep, 67(9), 1876 - 85
Surface pasteurization of whole fresh cantaloupes inoculated with Salmonella poona or Escherichia coli; Annous BA et al.; Numerous outbreaks of salmonellosis by Salmonella Poona have been associated with the consumption of cantaloupe . Commercial washing processes for cantaloupe are limited in their ability to inactivate or remove this human pathogen . Our objective was to develop a commercial-scale surface pasteurization process to enhance the microbiological safety of cantaloupe . Populations of indigenous bacteria recovered from cantaloupes that were surface pasteurized at 96, 86, or 76 degrees C for 2 to 3 min were significantly (P < 0.05) lower than those of the controls . Whole cantaloupes, surface inoculated with Salmonella Poona RM 2350 or Escherichia coli ATCC 25922 to a final cell concentration of ca . 5 log CFU/cm2 were stored at 4 degrees C or room temperature (RT = 19+/-1 degrees C) for up to 72 h before processing . Treatments at 76 degrees C for 2 to 3 min at 24 h postinoculation resulted in a reduction in excess of 5 log CFU/cm2 of Salmonella Poona and E . coli populations . Cantaloupes that were surface pasteurized and stored at 4 degrees C for 21 days retained their firmness qualities and had no visible mold growth compared with the controls, which became soft and moldy . These results indicate that surface pasteurization will enhance the microbiological safety of cantaloupes and will extend the shelf life of this commodity as well . Storage of untreated inoculated cantaloupes at RT for 24 to 72 h postinoculation caused a significant (P < 0.05) increase in Salmonella Poona and E . coli populations compared with storage at 4 degrees C . This indicates that cantaloupes should be refrigerated as soon as possible following harvest to suppress the growth of any possible contaminant on the rind.

Ned Tijdschr Geneeskd, 2004 Aug 21, 148(34), 1695 - 8
{Salmonella osteomyelitis in a child with sickle cell disease}; Juliana AE et al.; In an eight-months-old girl with sickle cell disease, osteomyelitis due to Salmonella arizona was diagnosed . Osteomyelitis caused by Salmonella species is rare in children . However, in patients with sickle cell disease it is the responsible pathogen in more than 50% of cases . The differentiation between, the much more common, bone crisis and osteomyelitis in sickle cell patients is often difficult . Ultrasound and bone marrow scans may be helpful . It is not known why Salmonella causes osteomyelitis in patients with sickle cell disease . What is clear, however, is that osteomyelitis usually occurs shortly after a preceding bone crisis . Empiric antibiotic treatment of osteomyelitis in patients with sickle cell disease should include coverage for Salmonella species . The patient described was initially treated with cefuroxime and gentamicin, but once the culture result was known this was switched to amoxicillin . As new infection foci later occurred in the bone the treatment was switched to ceftriaxone i.v . which was later substituted by ciprofloxacin orally . With this all of the skeletal abnormalities were fully corrected.

J Mol Biol, 2004 Oct 15, 343(2), 457 - 66
Structural and functional analysis of the C-terminal cytoplasmic domain of FlhA, an integral membrane component of the type III flagellar protein export apparatus in Salmonella; Saijo-Hamano Y et al.; FlhA is an integral membrane component of the Salmonella type III flagellar protein export apparatus . It consists of 692 amino acid residues and has two domains: the N-terminal transmembrane domain consisting of the first 327 amino acid residues, and the C-terminal cytoplasmic domain (FlhAC) comprising the remainder . Here, we have investigated the structure and function of FlhAC . DNA sequence analysis revealed that temperature-sensitive flhA mutations, which abolish flagellar protein export at the restrictive temperature, lie in FlhAC, indicating that FlhAC plays an important role in the protein export process . Limited proteolysis of purified His-FlhAC by trypsin and V8 showed that only a small part of FlhAC near its N terminus (residues 328-351) is sensitive to proteolysis . FlhAC38K, the smallest fragment produced by V8 proteolysis, is monomeric and has a spherical shape as judged by analytical gel filtration chromatography and analytical ultracentrifugation . The far-UV CD spectrum of FlhAC38K showed that it contains considerable amounts of secondary structure . FlhA(Delta328-351) missing residues 328-351 failed to complement the flhA mutant, indicating that the proteolytically sensitive region of FlhA is important for its function . FlhA(Delta328-351) was inserted into the cytoplasmic membrane, and exerted a strong dominant negative effect on wild-type cells, suggesting that it retains the ability to interact with other export components within the cytoplasmic membrane . Overproduced FlhAC38K inhibited both motility and flagellar protein export of wild-type cells to some degree, suggesting that FlhAC38K is directly involved in the translocation reaction . Amino acid residues 328-351 of FlhA appear to be a relatively flexible linker between the transmembrane domain and FlhAC38K.

FEMS Microbiol Lett, 2004 Oct 1, 239(1), 1 - 8
Chemotaxis in Vibrio cholerae; Boin MA et al.; The ability of motile bacteria to swim toward or away from specific environmental stimuli, such as nutrients, oxygen, or light provides cells with a survival advantage, especially under nutrient-limiting conditions . This behavior, called chemotaxis, is mediated by the bacteria changing direction by briefly reversing the direction of rotation of the flagellar motors . A sophisticated signal transduction system, consisting of signal transducer proteins, a histidine kinase, a response regulator, a coupling protein, and enzymes that mediate sensory adaptation, relates the input signal to the flagellar motor . Chemotaxis has been extensively studied in bacteria such as Escherichia coli and Salmonella enterica serovar Typhimurium, and depends on the activity of single copies of proteins in a linear pathway . However, growing evidence suggests that chemotaxis in other bacteria is more complex with many bacterial species having multiple paralogues of the various chemotaxis genes found in E . coli and, in most cases, the detailed functions of these potentially redundant genes have not been elucidated . Although the completed genome of Vibrio cholerae, the causative agent of cholera, predicted a multitude of genes with homology to known chemotaxis-related genes, little is known about their relative contribution to chemotaxis or other cellular functions . Furthermore, the role of chemotaxis during the environmental or infectious phases of this organism is not yet fully understood . This review will focus on the complex relationship between chemotaxis and virulence in V . cholerae.

Mutat Res, 2004 Oct 4, 554(1-2), 335 - 50
Comparative mutagenicity of halomethanes and halonitromethanes in Salmonella TA100: structure-activity analysis and mutation spectra; Kundu B et al.; Halonitromethanes (HNMs) are a recently identified class of disinfection by-products (DPBs) in drinking water that are mutagenic in Salmonella and potent inducers of DNA strand breaks in mammalian cells . Here we compared the mutagenic potencies of the HNMs to those of their halomethane (HM) homologues by testing all nine HNMs and seven of the nine HMs (minus bromomethane and chloromethane) under the same conditions (the pre-incubation assay) in Salmonella TA100 +/- S9 . We also determined the mutation spectra for several DBPs . In the presence of S9, all nine HNMs, but only three HMs, dibromomethane (DBM), dichloromethane (DCM), and bromochloromethane (BCM), were mutagenic . Only two DBPs of each class were mutagenic in the absence of S9 . The HNMs were generally more potent mutagens than their HM homologues, and the brominated forms of both classes of DBPs were more mutagenic and cytotoxic than their chlorinated homologues . The HNMs were at least 10 times more cytotoxic than the HMs, and the cytotoxicity rankings in the presence of S9 were similar for the HNMs and the HMs . The addition of a nitro-group to BCM did not change the mutation spectra significantly, with both homologues inducing primarily (55-58%) GC --> AT transitions . The greater cytotoxic and mutagenic activities of the HNMs relative to the HMs are likely due to the greater intrinsic reactivity conferred by the nitro-group . Energy calculations predicted increased reactivity with increasing bromination and greater reactivity of the HNMs versus the HMs (Elumo values were approximately 20 kcal/mol lower for the HNMs compared to their HM homologues) . Given that the HNMs also are potent genotoxins in mammalian cells {Environ . Sci . Technol . 38 (2004) 62} and are more mutagenic and 10x more cytotoxic in Salmonella than the HMs, whose levels are regulated in drinking water, further study of their occurrence and potential health effects is warranted.

Rev Esp Enferm Dig, 2004 Aug, 96(8), 559 - 62; 563-6
Abnormalities in liver enzyme levels during Salmonella enteritidis enterocolitis; Gonzalez-Quintela A et al.; OBJECTIVE: To evaluate the prevalence, associated factors, and time-course changes of abnormal liver enzyme serum levels in adult patients with Salmonella enteritidis enterocolitis . METHODS: The clinical records of 104 patients (age range 15-86 years, 46.2% males) admitted to hospital because of S . enteritidis enterocolitis were reviewed . The prevalence of abnormal liver enzyme levels was evaluated, as well as its possible relationship to data of systemic inflammatory response, severe sepsis, and bacteremia . In addition, time-course changes in serum levels of liver enzymes were studied in 16 cases with available follow-up after hospital discharge . RESULTS: In patients without a pre-existing cause for liver enzyme abnormalities (n = 84), the prevalence of serum AST elevation was 23.0% (95% CI 15.4-34.5%), of serum ALT elevation was 17.9% (95% CI 0.6-20.0%), and of GGT elevation was 19.0% (95% CI 11.6-29.3%) . The prevalence of abnormality for any of these enzymes (AST, ALT, or GGT) was 35.7% (95% CI 25.7-46.8%) . The prevalence of altered serum alkaline phosphatase was lower . Alteration in liver enzyme serum levels was moderate in the majority of cases, and was found in association with the presence of fever . Serum enzyme levels decreased during the convalescence period after hospital discharge . CONCLUSIONS: Abnormalities in liver enzyme levels are frequent during severe enterocolitis due to S . enteritidis in adult patients . These abnormalities are moderate and self-limited.

Trop Anim Health Prod, 2004 Jul, 36(5), 451 - 8
Salmonella prevalence and distribution of serotypes in apparently healthy slaughtered camels (Camelus dromedarius) in Eastern Ethiopia; Molla B et al.; The present study was undertaken to determine the prevalence and distribution of Salmonella from apparently healthy slaughtered camels in Eastern Ethiopia . A total of 714 samples (faeces, mesenteric, lymph nodes, spleen, liver, abdominal and diaphragmatic muscles) from 119 slaughtered camels were analysed . Salmonellae were detected from 116 (16.2%) of the 714 samples examined . Eighteen (15.1%) faeces, 19 (15.9%) mesenteric lymph nodes, 14 (11.8%) livers and 17 (14.3%) spleen samples (n = 119 for each) were positive for Salmonella . Salmonellae were found in 20.1% of the abdominal and diaphragmatic muscles . A total of sixteen different serotypes were identified of which Salmonella saintpaul (38.8%) and S . braenderup (22.4%) were the most prevalent followed by S . muenchen (8.6%), S . kottbus (6.0%) and S . havana (5.2%) . Other serotypes, including S . typhimurium, S . heidelberg and S . enteritidis were also detected from Ethiopian camels.

J Enzyme Inhib Med Chem, 2004 Apr, 19(2), 161 - 8
Antibacterial and antifugal mono- and di-substituted symmetrical and unsymmetrical triazine-derived Schiff-bases and their transition metal complexes; Chohan ZH et al.; A new series of antibacterial and antifungal triazine-derived mono- and di-substituted (symmetrical and unsymmetrical) Schiff-bases and their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments and IR and electronic spectral measurements . IR spectra indicated the ligands to act as tridentate towards divalent metal ions via a trazine-N, the azomethine-N and, indole-NH and deprotonated-O of salicylaldehyde . The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II) and Zn(II)complexes and square-pyramid for Cu(II) complexes . NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries . Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries . The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata . The results of these studies show the metal complexes to be more antibacterial/ antifungal against two or more species as compared to the uncomplexed Schiff-base ligands.

Lab Invest, 2004 Nov, 84(11), 1501 - 11
Control of Salmonella dissemination in vivo by macrophage inflammatory protein (MIP)-3alpha/CCL20; Fahy OL et al.; While chemokines are clearly important in the generation of protective immunity, the role of individual chemokines in the control of bacterial infection is still poorly understood . In this study, we investigated the role of macrophage inflammatory protein (MIP)-3alpha/CCL20, a chemokine that attracts activated T and B lymphocytes and immature dendritic cells, in host responses to bacterial infection . CCL20 production was induced in subcutaneous tissue in the BALB/c mouse in response to Salmonella enteritidis, Staphylococcus aureus and zymosan, with S . enteritidis being the most potent . S . enteritidis induced CCL20 production in the spleen following either oral administration or injection into the peritoneal cavity . In contrast, no increase was observed in the Peyer's patches . In this model, following intraperitoneal injection, dose-dependent colonization of the spleen and Peyer's patches by S . enteritidis, expression of IFNgamma and IL-4, and production of antibodies against the S . enteritidis surface antigen SefA were observed . Prior treatment with neutralizing antibodies against CCL20 enhanced bacterial dissemination to the spleen and Peyer's patches and strongly biased the IFNgamma/IL-4 ratio towards a type 2 profile in the spleen, while the humoral response was unaffected . In contrast, treatment with neutralizing anti-MIP-1alpha/CCL3 antibodies enhanced the bacterial burden in the Peyer's patches but not in the spleen, had no significant effect on the cytokine ratio, but significantly inhibited anti-SefA production . Together, these results demonstrate an important role for CCL20 in the control of bacterial infection and more specifically in the regulation of cell-mediated immunity against intracellular bacteria such as S . enteritidis.

Am J Gastroenterol, 2004 Oct, 99(10), 2041 - 5
Association of Helicobacter pylori infection with Shigella gastroenteritis in young children; Shmuely H et al.; OBJECTIVE: Helicobacter pylori infection is acquired mainly in early childhood . Much is unknown about the mode of transmission . The organism can be cultivated from cathartic stools and vomitus and is potentially transmissible during episodes of gastrointestinal tract illness . Because Shigella and Salmonella are common pathogens in enteric infections in children, we examined the association of H . pylori with Shigella and Salmonella infections in pediatric patients . METHODS: The study population included consecutive children aged 2-72 months hospitalized with acute gastroenteritis who had culture-proven shigellosis (N = 78) or salmonellosis (N = 76) . Sixty-five healthy similarly aged children with culture-negative stools served as controls . Parents of cases were queried for personal and family characteristics and socioeconomic indicators . The stool specimens from all participants were tested for H . pylori antigen . RESULTS: On univariate analysis, Shigella gastroenteritis was significantly associated with H . pylori positivity (odds ratio, OR: 3.5, 95% confidence interval (CI): 1.5-8.8, p= 0.004) compared to controls . This association remained significant even after adjusting for living conditions, father's occupation, and father's education (OR = 3.38, 95% CI: 1.39-8.22, p= 0.007) . Salmonella gastroenteritis was not associated with H . pylori positivity (OR = 1.1; 95% CI: 0.4-3.0, p= 0.8) . CONCLUSION: H . pylori infection in young children is associated with Shigella gastroenteritis . This association warrants further investigation.

J Pharm Sci, 2004 Nov, 93(11), 2718 - 23
TNFalpha measurement in rat and human whole blood as an in vitro method to assay pyrogens and its inhibition by dexamethasone and erythromycin; Martinez V et al.; To ensure the safety of potential drugs, pyrogen tests are traditionally performed in rabbits . New methods have been developed as alternatives to the test to reduce the use of experimental animals . Among these methods there are the Limulus amoebocyte lysate test and the determination of cytokine production by human leukocytes and whole blood . When exposed to a range of concentrations of endotoxins, human and rat whole blood release TNFalpha at amounts that are detectable by a commercially available enzyme-linked immunosorbent assay (ELISA) . Our results show that the sensitivity of human and rat blood to endotoxins from Salmonella abortus equi and Escherichia coli is similar . In rat blood, TNFalpha was detected after contact with the pyrogens only in fresh blood, collected on the same day of incubation with the pyrogenic substances . The measurement of TNFalpha production would be a reliable alternative to the rabbit pyrogen test . However, given that the addition of erythromycin and dexamethasone inhibited the production of this cytokine, this method is limited when parenteral formulations contain these two drugs . Similar inhibition has been observed in the rabbit test . Additional experiments will be necessary to demonstrate that the rat whole blood test system is useful and reliable for the pyrogens evaluation.

Antimicrob Agents Chemother, 2004 Oct, 48(10), 4012 - 5
Prevalence of mutations within the quinolone resistance-determining region of gyrA, gyrB, parC, and parE and association with antibiotic resistance in quinolone-resistant Salmonella enterica; Eaves DJ et al.; Salmonella enterica isolates (n = 182) were examined for mutations in the quinolone resistance-determining region of gyrA, gyrB, parC, and parE . The frequency, location, and type of GyrA substitution varied with the serovar . Mutations were found in parC that encoded Thr57-Ser, Thr66-Ile, and Ser80-Arg substitutions . Mutations in the gyrB quinolone resistance-determining region were located at codon Tyr420-Cys or Arg437-Leu . Novel mutations were also found in parE encoding Glu453-Gly, His461-Tyr, Ala498-Thr, Val512-Gly, and Ser518-Cys . Although it is counterintuitive, isolates with a mutation in both gyrA and parC were more susceptible to ciprofloxacin than were isolates with a mutation in gyrA alone.

Antimicrob Agents Chemother, 2004 Oct, 48(10), 3934 - 9
Mechanism of resistance to several antimicrobial agents in Salmonella Clinical isolates causing traveler's diarrhea; Cabrera R et al.; The evolution of antimicrobial resistance in Salmonella isolates causing traveler's diarrhea (TD) and their mechanisms of resistance to several antimicrobial agents were analyzed . From 1995 to 2002, a total of 62 Salmonella strains were isolated from stools of patients with TD . The antimicrobial susceptibility to 12 antibiotics was determined, and the molecular mechanisms of resistance to several of them were detected as well . The highest levels of resistance were found against tetracycline and ampicillin (21 and 19%, respectively), followed by resistance to nalidixic acid (16%), which was mainly detected from 2000 onward . Molecular mechanisms of resistance were analyzed in 16 isolates . In these isolates, which were resistant to ampicillin, two genes encoding beta-lactamases were detected: oxa-1 (one isolate) and tem-like (seven isolates {in one strain concomitantly with a carb-2}) . Resistance to tetracycline was mainly related to tetA (five cases) and to tetB and tetG (one case each) . Resistance to chloramphenicol was related to the presence of the floR and cmlA genes and to chloramphenicol acetyltransferase activity in one case each . Different genes encoding dihydrofolate-reductases (dfrA1, dfrA12, dfrA14, and dfrA17) were detected in trimethoprim-resistant isolates . Resistance to nalidixic acid was related to the presence of mutations in the amino acid codons 83 or 87 of the gyrA gene . Further surveillance of the Salmonella spp . causing TD is needed to detect trends in their resistance to antimicrobial agents, as we have shown in our study with nalidixic acid . Moreover, such studies will lead to better treatment and strategies to prevent and limit their spread.

Antimicrob Agents Chemother, 2004 Oct, 48(10), 3877 - 83
Fusidic acid-resistant mutants of Salmonella enterica serovar typhimurium have low levels of heme and a reduced rate of respiration and are sensitive to oxidative stress; Macvanin M et al.; Mutations in the translation elongation factor G (EF-G) make Salmonella enterica serovar Typhimurium resistant to the antibiotic fusidic acid . Fus(r) mutants are hypersensitive to oxidative stress and rapidly lose viability in the presence of hydrogen peroxide . We show that this phenotype is associated with reduced activity of two catalase enzymes, HPI (a bifunctional catalase-hydroperoxidase) and HPII (a monofunctional catalase) . These catalases require the iron-binding cofactor heme for their activity . Fus(r) mutants have a reduced rate of transcription of hemA, a gene whose product catalyzes the first committed step in heme biosynthesis . Hypersensitivity of Fus(r) mutants to hydrogen peroxide is abolished by the presence of delta-aminolevulinic acid, the precursor of heme synthesis, in the growth media and by the addition of glutamate or glutamine, amino acids required for the first step in heme biosynthesis . Fluorescence measurements show that the level of heme in a Fus(r) mutant is significantly lower than it is in the wild type . Heme is also an essential cofactor of cytochromes in the electron transport chain of respiration . We found that the rate of respiration is reduced significantly in Fus(r) mutants . Sequestration of divalent iron in the growth media decreases the sensitivity of Fus(r) mutants to oxidative stress . Taken together, these results suggest that Fus(r) mutants are hypersensitive to oxidative stress because their low levels of heme reduce both catalase activity and respiration capacity . The sensitivity of Fus(r) mutants to oxidative stress could be associated with loss of viability due to iron-mediated DNA damage in the presence of hydrogen peroxide . We argue that understanding the specific nature of antibiotic resistance fitness costs in different environments may be a generally useful approach in identifying physiological processes that could serve as novel targets for antimicrobial agents.

Antimicrob Agents Chemother, 2004 Oct, 48(10), 3806 - 12
Variant Salmonella genomic island 1 antibiotic resistance gene cluster containing a novel 3'-N-aminoglycoside acetyltransferase gene cassette, aac(3)-Id, in Salmonella enterica serovar newport; Doublet B et al.; Salmonella genomic island 1 (SGI1) harbors an antibiotic resistance gene cluster and was previously identified in the multidrug-resistant Salmonella enterica serovars Typhimurium DT104, Agona, Paratyphi B, and Albany . This antibiotic resistance gene cluster is a complex class 1 integron and most often confers resistance to ampicillin (Ap), chloramphenicol (Cm)/florfenicol (Ff), streptomycin (Sm)/spectinomycin (Sp), sulfonamides (Su), and tetracycline (Tc) (ApCmFfSmSpSuTc profile) . Recently, variant SGI1 antibiotic resistance gene clusters conferring different antibiotic resistance profiles have been identified in several S . enterica serovars and were classified as SGI1-A to -G . We identified a new variant SGI1 antibiotic resistance gene cluster in two multidrug-resistant S . enterica serovar Newport strains isolated from humans in France . In these strains, the Sm/Sp resistance gene cassette aadA2 inserted at the first attI1 site was replaced by two other aminoglycoside resistance gene cassettes . The first one contains a new resistance gene encoding an AAC(3)-I aminoglycoside 3-N-acetyltransferase that confers resistance to gentamicin (Gm) and sisomicin (Sc) . This gene has been named aac(3)-Id . The second one harbors the Sm/Sp resistance gene aadA7 . This gene cassette replacement in the SGI1 complex integron of serovar Newport strains constitutes a new variant SGI1 antibiotic resistance gene cluster named SGI1-H . The occurrence of SGI1 in different S . enterica serovars, now including serovar Newport, strengthens the hypothesis of horizontal transfer of SGI1.

Antimicrob Agents Chemother, 2004 Oct, 48(10), 3789 - 93
Increasing prevalence of quinolone resistance in human nontyphoid Salmonella enterica isolates obtained in Spain from 1981 to 2003; Marimon JM et al.; From January 1981 to December 2003, susceptibility to nalidixic acid was tested in 10,504 nontyphoid Salmonella enterica isolates from patients with acute enteric disease in Gipuzkoa, Spain . The prevalence of nalidixic acid resistance steadily increased from less than 0.5% before 1991 to 38.5% in 2003, mainly due to the increase in resistance among isolates of the most prevalent serovar, S . enterica serovar Enteritidis . For nalidixic acid-resistant isolates, the ciprofloxacin MIC was eightfold higher than that for susceptible isolates, and the nalidixic acid-resistant isolates contained a single point mutation in the gyrA gene (at codons for Ser83 or Asp87) . The same mutations were found in a sample of nalidixic acid-resistant nontyphoid Salmonella strains isolated between 1999 and 2003 from retail food for human consumption . In 2003, we identified five S . enterica serovar Typhimurium clinical isolates with high-level fluoroquinolone resistance (ciprofloxacin MIC, 16 microg/ml) with two point mutations in the gyrA gene (coding for Ser83-->Phe and Asp87-->Asn) and one point mutation in the parC gene (coding for Ser80-->Arg) . Strict sanitary controls are needed to avoid the spread of ciprofloxacin-resistant serovar Typhimurium isolates, and a more efficient veterinary policy must be adopted to decrease the large burden of Salmonella serovar Enteritidis infections in humans in our region.

Antimicrob Agents Chemother, 2004 Oct, 48(10), 3729 - 35
AcrAB-TolC directs efflux-mediated multidrug resistance in Salmonella enterica serovar typhimurium DT104; Baucheron S et al.; Multidrug-resistant Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) strains harbor a genomic island, called Salmonella genomic island 1 (SGI1), which contains an antibiotic resistance gene cluster conferring resistance to ampicillin, chloramphenicol, florfenicol, streptomycin, sulfonamides, and tetracyclines . They may be additionally resistant to quinolones . Among the antibiotic resistance genes there are two, i.e., floR and tet(G), which code for efflux pumps of the major facilitator superfamily with 12 transmembrane segments that confer resistance to chloramphenicol-florfenicol and the tetracyclines, respectively . In the present study we determined, by constructing acrB and tolC mutants, the role of the AcrAB-TolC multidrug efflux system in the multidrug resistance of several DT104 strains displaying additional quinolone resistance or not displaying quinolone resistance . This study shows that the quinolone resistance and the decreased fluoroquinolone susceptibilities of the strains are highly dependent on the AcrAB-TolC efflux system and that single mutations in the quinolone resistance-determining region of gyrA are of little relevance in mediating this resistance . Overproduction of the AcrAB efflux pump, as determined by Western blotting with an anti-AcrA polyclonal antibody, appeared to be the major mechanism of resistance to quinolones . Moreover, chloramphenicol-florfenicol and tetracycline resistance also appeared to be highly dependent on the presence of AcrAB-TolC, since the introduction of mutations in the respective acrB and tolC genes resulted in a susceptible or intermediate resistance phenotype, according to clinical MIC breakpoints, despite the presence of the FloR and Tet(G) efflux pumps . Resistance to other antibiotics, ampicillin, streptomycin, and sulfonamides, was not affected in the acrB and tolC mutants of DT104 strains harboring SGI1 . Therefore, AcrAB-TolC appears to direct efflux-mediated resistance to quinolones, chloramphenicol-florfenicol, and tetracyclines in multidrug-resistant S . enterica serovar Typhimurium DT104 strains.

Carbohydr Res, 2004 Oct 4, 339(14), 2441 - 3
The structure of the O-specific polysaccharide from Salmonella cerro (serogroup K, O:6,14,18); Vinogradov E et al.; The following structure of the Salmonella cerro LPS O-chain repeating unit has been determined using NMR and chemical methods: -->4)-alpha-D-Man(1-->2)-alpha-D-Man(1-->2)-beta-D-Man(1-->3)-alpha-D-GalNAc-(1-->.

Mol Microbiol, 2004 Sep, 53(5), 1437 - 49
Repression of the RcsC-YojN-RcsB phosphorelay by the IgaA protein is a requisite for Salmonella virulence; Dominguez-Bernal G et al.; Bacterial pathogenesis relies on regulators that activate virulence genes . Some of them act, in addition, as repressors of specific genes . Intracellular-growth-attenuator-A (IgaA) is a Salmonella enterica membrane protein that prevents overactivation of the RcsC-YojN-RcsB regulatory system . This negative control is critical for growth because disruption of the igaA gene is only possible in rcsC, yojN or rcsB strains . In this work, we examined the contribution of this regulatory circuit to virulence . Viable igaA point mutant alleles were isolated and characterized . These alleles encode IgaA variants leading to different levels of activation of the RcsC-YojN-RcsB system . IgaA-mediated repression of the RcsB-YojN-RcsC system occurred at the post-translational level, as shown by chromosomal epitope tagging of the rcsC, yojN and rcsB genes . The activity of the RcsC-YojN-RcsB system, monitored with the product of a tagged gmd-3xFLAG gene (positively regulated by RcsC-YojN-RcsB), was totally abolished by wild-type bacteria in mouse target organs . Such tight repression occurred only in vivo and was mediated by IgaA . Shutdown of the RcsC-YojN-RcsB system is a requisite for Salmonella virulence since all igaA point mutant strains were highly attenuated . The degree of attenuation correlated to that of the activation status of RcsC-YojN-RcsB . In some cases, the attenuation recorded was unprecedented, with competitive index (CI) values as low as 10(-6) . Strikingly, IgaA is a protein absolutely dispensable for virulence in mutant strains having a non-functional RcsC-YojN-RcsB system . To our knowledge, IgaA exemplifies the first protein that contributes to virulence by exclusively acting as a negative regulator upon host colonization .

Infect Immun, 2004 Oct, 72(10), 5824 - 31
Role of B7 costimulatory molecules in mediating systemic and mucosal antibody responses to attenuated Salmonella enterica serovar Typhimurium and its cloned antigen; Garcia CA et al.; The purpose of the present study was to evaluate the ability of an attenuated Salmonella enterica serovar Typhimurium vaccine strain to up-regulate B7-1 and B7-2 on antigen-presenting cells and to examine the functional roles these costimulatory molecules play in mediating immune responses to Salmonella and to an expressed cloned antigen, the saliva-binding region (SBR) of antigen I/II . In vitro stimulation of B cells (B220+), macrophages (CD11b+), and dendritic cells (CD11c+) with S . enterica serovar Typhimurium induced an up-regulation of B7-2 and, especially, B7-1 expression . The in vivo functional roles of B7-1, B7-2, and B7-1/2 were evaluated in BALB/c wild-type and B7-1, B7-2, and B7-1/2 knockout (KO) mice following intranasal immunization with the Salmonella expressing the cloned SBR . Differential requirements for B7-1 and B7-2 were observed upon primary and secondary immunizations . Compared to wild-type controls, B7-1 and B7-2 KO mice had reduced mucosal and systemic anti-Salmonella antibody responses after a single immunization, while only B7-1 KO mice exhibited suppressed anti-Salmonella antibody responses following the second immunization . Mucosal and systemic antibody responses to SBR were reduced following the primary immunization, whereas a compensatory role for either B7-1 or B7-2 was observed after the second immunization . B7-1/2 double KO mice failed to induce detectable levels of mucosal or systemic immunoglobulin A (IgA) or IgG antibody responses to either Salmonella or SBR . These findings demonstrate that B7-1 and B7-2 can play distinct as well as redundant roles for mediating mucosal and systemic antibody responses, which are likely dependent upon the nature of the antigen.

Infect Immun, 2004 Oct, 72(10), 5613 - 21
Structural organization of the pFra virulence-associated plasmid of rhamnose-positive Yersinia pestis; Golubov A et al.; The 137,036-bp plasmid pG8786 from rhamnose-positive Yersinia pestis G8786 isolated from the high mountainous Caucasian plague focus in Georgia is an enlarged form of the pFra virulence-associated plasmid containing genes for synthesis of the antigen fraction 1 and phospholipase D . In addition to the completely conserved genes of the pFra backbone, pG8786 contains two large regions consisting of 4,642 and 32,617 bp, designated regions 1 and 2, respectively . Region 1 retains a larger part of Salmonella enterica serovar Typhi plasmid pHCM2 resembling the backbone of pFra replicons, while region 2 contains 25 open reading frames with high levels of similarity to the transfer genes of the F-like plasmids . Surprisingly, region 1 is also present in the pFra plasmid of avirulent Y . pestis strain 91001 isolated in Inner Mongolia, People's Republic of China . Despite the fact that some genes typically involved in conjugative transfer of the F-like replicons are missing in pG8786, we cannot exclude the possibility that pG8786 might be transmissive under certain conditions . pG8786 seems to be an ancient form of the pFra group of plasmids that were conserved due to the strict geographical isolation of rhamnose-positive Y . pestis strains in the high mountainous Caucasian plague locus.

Poult Sci, 2004 Sep, 83(9), 1602 - 9
Phenotypic selection for residual feed intake and its effect on humoral immune responses in growing layer hens; Van Eerden E et al.; According to the resource allocation theory, animals have to make a trade-off between resource-demanding life traits to obtain maximal fitness . Artificial selection toward efficient producing farm animals, however, may have created animals that have an impaired ability to divert resources to maintenance processes, such as responding to immune challenges . Residual feed intake (RFI), defined as the difference between observed feed intake (FI) and expected feed intake based on metabolic BW and growth, was used as a measure for feed efficiency . Individual BW and FI of 352 pullets were recorded weekly from 4 until 14 wk of age to estimate RFI . The top 50 efficient R- and the top 50 nonefficient R+ birds were selected . BW and BW gain in both groups were similar . FI and RFI, however, were significantly higher in R+ birds . Thirty animals out of every group were randomly allocated to 1 of 3 treatments: immunization with keyhole limpet hemocyanin (KLH), Mycobacterium butyricum, or heat-inactivated Salmonella enteritidis bacteria . Antibody titers against KLH, M . butyricum, or Salmonella lipopolysaccharide did not differ between R+ and R- birds . The antibody titer against Salmonella protein was higher in R+ birds . We concluded that a population of chickens from a commercial breed shows considerable variation in RFI . Specific antibody production against KLH, M . butyricum, and S . enteritidis lipopolysaccharide, however, is not influenced by efficiency in terms of RFI . R+ animals may have a higher level of nonantigen specific antibodies, as indicated by the higher antibody response to Salmonella protein.

Eur J Immunol, 2004 Nov, 34(11), 2986 - 95
Responses to the soluble flagellar protein FliC are Th2, while those to FliC on Salmonella are Th1; Cunningham AF et al.; Features of the Th1 or Th2 phenotype start to develop during CD4 T cell priming . This study of the response to the bacterial flagellar protein FliC shows that either Th1 or Th2 responses can be induced in mice depending upon how FliC is presented . This is shown by assessing the cytokine mRNA and class of FliC-specific plasma cells induced in situ . Soluble recombinant (r)FliC and polymerized FliC are strongly Th2 polarizing, inducing IL-4, NIP45 and c-Maf mRNA as well as epsilon and gamma1 switch transcripts and switching to IgG1 . CD28-requirement for this switching shows its T cell dependence . rFliC was unable to induce markers of Th1 activity including IL-12, T-bet and IFN-gamma . Conversely, when FliC is presented in its native context surface-bound on live, flagellated Salmonella, switching is predominantly to IgG2a (IgG2c in C57BL/6 mice), reflecting Th1 activity . The development of divergent FliC-specific polarization to either Th1 or Th2 indicates that the context in which this antigen is encountered rather than its intrinsic immunostimulatory properties determines the direction of Th polarization.

Microbiol Immunol, 2004, 48(9), 639 - 45
Identification and characterization of class 1 integron resistance gene cassettes among Salmonella strains isolated from healthy humans in China; Zhang H et al.; Twenty-three strains of Salmonella spp . isolated from healthy humans in Guangdong, China, were examined for their susceptibility to ten common antibiotics and the presence of antibiotic resistance integrons . All the strains were resistant to at least one antibiotic, and 4 strains were positive for the intI1 gene . Polymerase chain reaction using in-F and in-B primers showed the existence of amplicons of 1,009 bp in two, 1,664 bp in one, and 1,009 bp and 1,664 bp in one of the intI1 -positive isolates, respectively . Sequence analysis revealed that the 1,009-bp amplicon harbored gene cassette aadA2, conferring resistance to spectinomycin, and the 1,664-bp amplicon harbored genes aadA5 and dfr17, conferring resistance to spectinomycin, streptomycin and trimethoprim . Meanwhile the experiments of plasmid conjugation and Southern hybridization with intI1 as the DNA probe indicated that all the integrons found in these strains were chromosomal . Because the strains carrying class 1 integrons were isolated from healthy humans, it suggests the need for all-round surveillance of the antibiotic resistance of pathogens.

RNA, 2004 Oct, 10(10), 1662 - 73
The modified wobble nucleoside uridine-5-oxyacetic acid in tRNAPro(cmo5UGG) promotes reading of all four proline codons in vivo; Nasvall SJ et al.; In Salmonella enterica serovar Typhimurium five of the eight family codon boxes are decoded by a tRNA having the modified nucleoside uridine-5-oxyacetic acid (cmo5U) as a wobble nucleoside present in position 34 of the tRNA . In the proline family codon box, one (tRNAProcmo5UGG) of the three tRNAs that reads the four proline codons has cmo5U34 . According to theoretical predictions and several results obtained in vitro, cmo5U34 should base pair with A, G, and U in the third position of the codon but not with C . To analyze the function of cmo5U34 in tRNAProcmo5UGG in vivo, we first identified two genes (cmoA and cmoB) involved in the synthesis of cmo5U34 . The null mutation cmoB2 results in tRNA having 5-hydroxyuridine (ho5U34) instead of cmo5U34, whereas the null mutation cmoA1 results in the accumulation of 5-methoxyuridine (mo5U34) and ho5U34 in tRNA . The results suggest that the synthesis of cmo5U34 occurs as follows: U34 -->(?) ho5U -->(CmoB) mo5U -->(CmoA?) cmo5U . We introduced the cmoA1 or the cmoB2 null mutations into a strain that only had tRNAProcmo5UGG and thus lacked the other two proline-specific tRNAs normally present in the cell . From analysis of growth rates of various strains and of the frequency of +1 frameshifting at a CCC-U site we conclude: (1) unexpectedly, tRNAProcmo5UGG is able to read all four proline codons; (2) the presence of ho5U34 instead of cmo5U34 in this tRNA reduces the efficiency with which it reads all four codons; and (3) the fully modified nucleoside is especially important for reading proline codons ending with U or C .

J Biol Chem, 2004 Nov 26, 279(48), 49804 - 15 Epub 2004 Nov 26.
Expression and secretion of Salmonella pathogenicity island-2 virulence genes in response to acidification exhibit differential requirements of a functional type III secretion apparatus and SsaL; Coombes BK et al.; Salmonella pathogenicity island (SPI)-2 is pivotal to the intracellular survival of Salmonella and for virulence in mammals . SPI-2 encodes virulence factors (called effectors) that are translocated into the host cell, a type III secretion apparatus and a two-component regulatory system that regulates intracellular expression of SPI-2 . Salmonella SPI-2 secretion activity appears to be induced in response to acidification of the vacuole in which it replicates . Here we show that the expression of the SPI-2 proteins, SseB and SseD (filament and pore forming components of the secretion apparatus, respectively) in response to acidification requires an intact secretion system and SsaL, a Salmonella homologue of SepL, a regulator required for type III-dependent secretion of translocators but not effectors in attaching and effacing gastrointestinal pathogens . We show that the expression of SPI-2-encoded effectors is acid-regulated but can be uncoupled from the expression of filament and translocon components, thus showing a differential requirement of SsaL for expression . The secretion and translocation of SPI-2-encoded effectors requires SsaL, but SsaL is dispensable for the secretion of SPI-2 effectors encoded in other pathogenicity loci, suggesting a secretion regulation function for SsaL . Further, we demonstrate that the differential expression of adjacent genes within the sseA operon (sseD and sseE) occurs at the transcriptional level . These data indicate that a Salmonella SPI-2 activation state is achieved by an acidregulated response that requires SsaL . These data also suggest the existence of a previously unrecognized regulatory element within SPI-2 for the "effector operon" region downstream of sseD that might demarcate the expression of translocators and effectors.

Vet Microbiol, 2004 Oct 5, 103(1-2), 71 - 6
Phage types, ribotypes and tetracycline resistance genes of Salmonella enterica subsp . enterica serovar Typhimurium strains isolated from different origins in Italy; Pasquali F et al.; The tetracycline resistance (tet) gene patterns of 52 tetracycline resistant Salmonella enterica subsp . enterica (S.) serovar Typhimurium isolates collected from animals, food of animal origin, and humans in Italy, were investigated to evaluate whether the tet gene patterns could be used for strain differentiation in addition to phage typing and ribotyping . The detection of tet genes was performed by specific PCR assays . Ribotyping was performed automatically using PvuII as restriction enzyme . Ten different ribotyping patterns were detected . All isolates were positive for at least one of the tet genes studied and six different tet gene patterns were observed . Ribotyping and tet gene patterns showed discriminatory indices of 0.741 and 0.812, respectively . Multiple tet genes were commonly found among tetracycline resistant S . typhimurium isolates from various sources . The resulting tet gene patterns allowed further discrimination of strains which were otherwise indistinguishable by their phage type, ribotype and origin . Thus, the analysis of tet gene patterns might represent an additional tool for the differentiation of S . typhimurium isolates.

Int J Antimicrob Agents, 2004 Oct, 24(4), 327 - 33
Detection of integrons and antibiotic-resistance genes in Salmonella enterica serovar Typhimurium isolates with resistance to ampicillin and variable susceptibility to amoxicillin-clavulanate; Guerri ML et al.; We characterized 29 antimicrobial-resistant Salmonella enterica serovar Typhimurium strains, including four belonging to the monophasic variant 4,5,12:i:-, mostly isolated from infants . They were selected from 3230 strains isolated in the years 1990-2001 on the basis of resistance to ampicillin and variable susceptibility to the amoxicillin-clavulanate combination . Twenty-three strains were resistant to more than four antibiotics . All the strains carried the bla(TEM) gene and most were able to transfer this gene by conjugation . Sequencing of the gene from one of the amoxicillin-clavulanate-resistant strains allowed identification of the encoded beta-lactamase as TEM-1; all of these strains carried a second gene encoding beta-lactamase production, either pse-1 or oxa1 . However, the association of bla(TEM) plus pse-1 genes did not always confer resistance to amoxicillin-clavulanate . The pse-1 gene, found in 17 strains, was located in the Salmonella Genomic Island-1 (SGI1), which carries two integrons and encodes multiple drug-resistance . None of the oxa1-bearing strains had the SGI1, yet this gene was found as part of an integron that also carried the aadA1 gene and was not plasmid-associated . Thirteen of the strains harbouring SGI1 belonged to the definitive phage type (DT) 104, and most of those remaining to DT104b and U302; particularly, strains carrying the oxa1-aadA1 integron belonged to the last two phage types . Pulsed field electrophoresis confirmed the clonal organization of DT104 strains, whereas U302 strains fell into different groups, depending on their resistance determinants.

Chem Biol, 2004 Sep, 11(9), 1307 - 16
Dual effects of MLS antibiotics: transcriptional modulation and interactions on the ribosome; Tsui WH et al.; The macrolide-lincosamide-streptogramin (MLS) antibiotics are an important group of translation inhibitors that act on the 50S ribosome . We show that, at subinhibitory concentrations, members of the MLS group modulate specific groups of bacterial promoters, as detected by screening a library of promoter-luxCDABE reporter clones of Salmonella enterica serovar Typhimurium . The patterns of transcription permit identification of classes of promoters having differential responses to antibiotics of related structure and mode-of-action; studies of antibiotic synergy or antagonism showed that eukaryotic translation inhibitors may act on the 50S ribosome . The mechanism of transcriptional modulation is not known but may involve bacterial stress responses and/or the disturbance and subsequent compensation of metabolic networks as a result of subtle interference with ribosome function . Transcriptional patterns detected with promoter-lux clones provide a novel approach to antibiotic discovery and mode-of-action studies.

BMC Infect Dis . 2004 Sep 20;4(1):36.
Suboptimal clinical response to ciprofloxacin in patients with enteric fever due to Salmonella spp . with reduced fluoroquinolone susceptibility: a case series; Slinger R et al.; BACKGROUND: Salmonella spp . with reduced susceptibility to fluoroquinolones have higher than usual MICs to these agents but are still considered "susceptible" by NCCLS criteria . Delayed treatment response to fluoroquinolones has been noted, especially in cases of enteric fever due to such strains . We reviewed the ciprofloxacin susceptibility and clinical outcome of our recent enteric fever cases . METHODS: Salmonella enterica Serotype Typhi (S . Typhi) and Serotype Paratyphi (S . Paratyphi) blood culture isolates (1998-2002) were tested against nalidixic acid by disk diffusion (DD) and agar dilution (AD) and to ciprofloxacin by AD using NCCLS methods and interpretive criteria . Reduced fluoroquinolone susceptibility was defined as a ciprofloxacin MIC of 0.125-1.0 mg/L . The clinical records of patients treated with ciprofloxacin for isolates with reduced fluoroquinolone susceptibility were reviewed . RESULTS: Seven of 21 (33%) S . Typhi and S . Paratyphi isolates had reduced susceptibility to fluoroquinolones (MIC range 0.125-0.5 mg/L) . All 7 were nalidixic acid resistant by DD (no zone) and by AD (MIC 128- >512 mg/L) . The other 14 isolates were nalidixic acid susceptible and fully susceptible to ciprofloxacin (MIC range 0.015-0.03 mg/L).Five of the 7 cases were treated initially with oral ciprofloxacin . One patient remained febrile on IV ciprofloxacin until cefotaxime was added, with fever recurrence when cefotaxime was discontinued . Two continued on oral or IV ciprofloxacin alone but had prolonged fevers of 9-10 days duration, one was switched to IV beta-lactam therapy after remaining febrile for 3 days on oral/IV ciprofloxacin and one was treated successfully with oral ciprofloxacin . Four of the 5 required hospitalization . CONCLUSIONS: Our cases provide further evidence that reduced fluoroquinolone susceptibility of S . Typhi and S . Paratyphi is clinically significant . Laboratories should test extra-intestinal Salmonella spp . for reduced fluoroquinolone susceptibility.

Biochemistry, 2004 Sep 28, 43(38), 11998 - 2008
solution structure, backbone dynamics, and interaction with Cdc42 of Salmonella guanine nucleotide exchange factor SopE2; Williams C et al.; SopE and SopE2 are delivered by the Salmonella type III secretion system into eukaryotic cells to promote cell invasion . SopE and SopE2 are potent guanine nucleotide exchange factors (GEFs) for Rho GTPases Cdc42 and Rac1 and constitute a novel class of Rho GEFs . Although the sequence of SopE-like GEFs is not at all homologous to those of the Dbl homology domain-containing eukaryotic GEFs, the mechanism of nucleotide release seems to have significant similarities . We have determined the solution structure of the catalytic domain (residues 69-240) of SopE2, showing that SopE2(69-240) comprises two three-helix bundles (alpha1alpha4alpha5 and alpha2alpha3alpha6) arranged in a Lambda shape . Compared to the crystal structure of SopE(78-240) in complex with Cdc42, SopE2(69-240) exhibits a less open Lambda shape due to movement of SopE(78-240) helices alpha2 and alpha5 to accommodate binding to the Cdc42 switch regions . In an NMR titration to investigate the SopE2(69-240)-Cdc42 interaction, the SopE2(69-240) residues affected by binding Cdc42 were very similar to the SopE(78-240) residues that contact Cdc42 in the SopE(78-240)-Cdc42 complex . Analysis of the backbone (15)N dynamics of SopE2(69-240) revealed flexibility in residues that link the two three-helix bundles, including the alpha3-alpha4 linker that incorporates a beta-hairpin and the catalytic loop, and the alpha5-alpha6 loop, and flexibility in residues involved in interaction with Cdc42 . Together, these observations provide experimental evidence of a previously proposed mechanism of GEF-mediated nucleotide exchange based on the Rac1-Tiam1 complex structure, with SopE/E2 flexibility, particularly in the interbundle loops, enabling conformational rearrangements of the nucleotide binding region of Cdc42 through an induced fit type of binding . Such flexibility in SopE/E2 may also facilitate interaction through adaptive binding with alternative target proteins such as Rab5, allograft inflammatory factor 1, and apolipoprotein A-1.

Cancer Gene Ther . 2004 Sep 17; {Epub ahead of print}
Systemic administration of attenuated Salmonella choleraesuis carrying thrombospondin-1 gene leads to tumor-specific transgene expression, delayed tumor growth and prolonged survival in the murine melanoma model; Lee CH et al.; Some anaerobic and facultative anaerobic bacteria have been used experimentally as anticancer agents because of their selective growth in the hypoxia regions of solid tumors after systemic administration . We have previously shown the feasibility of using attenuated Salmonella choleraesuis as a gene delivery vector . In this study, we exploited S . choleraesuis carrying thrombospondin-1 (TSP-1) gene for treating primary melanoma and experimental pulmonary metastasis in the syngeneic murine B16F10 melanoma model . Systemic administration of S . choleraesuis allowed targeted gene delivery to tumors . The bacteria accumulated preferentially in tumors over livers and spleens at ratios ranging from 1000:1 to 10,000:1 . The level of transgene expression via S . choleraesuis-mediated gene transfer in tumors could reach more than 1800-fold higher than in livers and spleens . Notably, bacterial accumulation was also observed in the lungs with metastatic nodules, but not in healthy lungs . When administered into mice bearing subcutaneous or pulmonary metastatic melanomas, S . choleraesuis carrying TSP-1 gene significantly inhibited tumor growth and enhanced survival of the mice . Immunohistochemical studies in the tumors from these mice displayed decreased intratumoral microvessel density . Taken together, these findings suggest that TSP-1 gene therapy delivered by S . choleraesuis may be effective for the treatment of primary as well as metastatic melanomas.Cancer Gene Therapy advance online publication, 17 September 2004; doi:10.1038/sj.cgt.7700777

Nat Rev Microbiol, 2004 Sep, 2(9), 747 - 65
Persistent bacterial infections: the interface of the pathogen and the host immune system; Monack DM et al.; Persistent bacterial infections involving Mycobacterium tuberculosis, Salmonella enterica serovar Typhi (S . typhi) and Helicobacter pylori pose significant public-health problems . Multidrug-resistant strains of M . tuberculosis and S . typhi are on the increase, and M . tuberculosis and S . typhi infections are often associated with HIV infection . This review discusses the strategies used by these bacteria during persistent infections that allow them to colonize specific sites in the host and evade immune surveillance . The nature of the host immune response to this type of infection and the balance between clearance of the pathogen and avoidance of damage to host tissues are also discussed.

Genes Dev, 2004 Sep 15, 18(18), 2302 - 13
Connecting two-component regulatory systems by a protein that protects a response regulator from dephosphorylation by its cognate sensor; Kato A et al.; A fundamental question in signal transduction is how an organism integrates multiple signals into a cellular response . Here we report the mechanism by which the Salmonella PmrA/PmrB two-component system responds to the signal controlling the PhoP/PhoQ two-component system . We establish that the PhoP-activated PmrD protein binds to the phosphorylated form of the response regulator PmrA, preventing both its intrinsic dephosphorylation and that promoted by its cognate sensor kinase PmrB . This results in PmrA-mediated transcription because phosphorylated PmrA exhibits higher affinity for its target promoters than unphosphorylated PmrA . A PmrD-independent form of the PmrA protein was resistant to PmrB-catalyzed dephosphorylation and promoted transcription of PmrA-activated genes in the absence of inducing signals . This is the first example of a protein that enables a two-component system to respond to the signal governing a different two-component system by protecting the phosphorylated form of a response regulator.

J Toxicol Environ Health A, 2004 Oct 22-Nov 26, 67(20-22), 1643 - 53
Bacterial pathogens in rural water supplies in Southern Alberta, Canada; Gannon VP et al.; Raw river and irrigation water in the Oldman River Basin in southern Alberta was tested for the presence of two bacterial pathogens, Escherichia coli O157:H7 and Salmonella spp., over the last 2 yr (2000-2001) . The number of E . coli O157:H7 and Salmonella spp . isolated from raw water peaked during the summer months . While E . coli O157:H7 was only isolated from 11/802 (1.35%) of raw water samples over the entire sampling season in 2000 and from 16/806 (2.05%) of the samples in 2001, the pathogen was isolated one or more times from 10/35 (28.55%) sampling sites in 2000 and from 13/40 (32.55%) sampling sites in 2001 . Salmonella was isolated from 44/802 (5.55%) of raw water samples in 2000 and from 122/822 (14.95%) of the samples in 2001; the pathogen was isolated one or more times from 25/35 (71.45%) sampling sites in 2000 and from 29/40 (72.55%) sampling sites in 2001 . Certain sites had multiple pathogen isolations in the same year and from year to year . Salmonella Rublislaw was the most common Salmonella serovar isolated in both years, accounting for 52.45% of isolates.

Scand J Infect Dis, 2004, 36(8), 547 - 51
Salmonella bacteraemia in a tertiary children's hospital; Papaevangelou V et al.; A retrospective study was conducted between July 1990 and July 2002 to investigate the epidemiology, clinical characteristics, and the outcome of Salmonella bacteraemia in children . A total of 148 episodes of bacteraemia were identified in 144 children . The annual incidence ranged from 1.6 to 8.3 cases per 100,000 children < or = 14 y of age, and higher numbers of cases occurred in summer than in winter months . In 22 children the bacteraemia was caused by S . typhi and in 122 by S . non-typhi . S . enteritidis was the most common serotype isolated . Resistance to ampicillin was exhibited by 28.5% of Salmonella isolates, whereas all S . typhi isolates were susceptible to commonly used antibiotics . The mean age was 40.3 months (range 50 d to 14 y) . Children with S . typhi bacteraemia were significantly older than children with S . non-typhi bacteraemia (7.8 vs 2.4 y, p < 0.01) . 11 children were immunosuppressed . The immunosuppressed children had longer duration of fever, longer hospitalization stay, and higher relapse rates compared to normal children (p < 0.05) . Four children developed complications and 1 died . Although the incidence of S . typhi bacteraemia is decreasing, the non-typhi species continue to cause significant morbidity in our geographical region.

SAR QSAR Environ Res, 2004 Aug, 15(4), 251 - 63
Searching for an enhanced predictive tool for mutagenicity; Klopman G et al.; The Multiple Computer Automated Structure Evaluation (MCASE) program was used to evaluate the mutagenic potential of organic compounds . The experimental Ames test mutagenic activities for 2513 chemicals were collected from various literature sources . All chemicals have experimental results in one or more Salmonella tester strains . A general mutagenicity data set and fifteen individual Salmonella test strain data sets were compiled . Analysis of the learning sets by the MCASE program resulted in the derivation of good correlations between chemical structure and mutagenic activity . Significant improvement was obtained as more data was added to the learning databases when compared with the results of our previous reports . Several biophores were identified as being responsible for the mutagenic activity of the majority of active chemicals in each individual mutagenicity module . It was shown that the multiple-database mutagenicity model showed a clear advantage over normally used single-database models . The expertise produced by this analysis can be used to predict the mutagenic potential of new compounds.

J Microbiol Methods, 2004 Nov, 59(2), 163 - 72
Multiple-locus variable-number tandem-repeats analysis of Salmonella enterica subsp . enterica serovar Typhimurium using PCR multiplexing and multicolor capillary electrophoresis; Lindstedt BA et al.; The multiple-locus variable-number tandem-repeats analysis (MLVA) method is currently being used as the primary typing tool for Salmonella enterica subsp . enterica serovar Typhimurium (S . Typhimurium) isolates in our laboratory . Our published initial MLVA was performed using a single fluorescent dye and the different patterns were assigned from gel images . Here we present a new and significantly improved assay using multiple dye colors, enhanced PCR multiplexing and the introduction of two new loci for better adaptation to capillary electrophoresis with increased speed . The different MLVA patterns are now based on allele sizes entered as character values, thus removing the uncertainties introduced when analyzing band patterns from gel images . We additionally propose an easy numbering scheme for the identification of separate isolates that will facilitate exchange of typing data . A total of 106 human, bird, animal and food isolates of S . Typhimurium, including 16 with definite type (DT) 104, were used for the development of the improved MLVA . The method is based on capillary separation of multiplexed PCR products from five VNTR loci in the S . Typhimurium genome labeled with multiple fluorescent dyes . The different alleles at each locus were then assigned allele numbers, which were used for strain comparison.

BMC Infect Dis . 2004 Sep 14;4(1):35.
Nosocomial outbreak of neonatal Salmonella enterica serotype Enteritidis meningitis in a rural hospital in northern Tanzania; Vaagland H et al.; BACKGROUND: Clinicians at Haydom Lutheran Hospital, a rural hospital in northern Tanzania noted an unusually high case-fatality rate of pediatric meningitis and suspected an outbreak of an unknown agent or an organism resistant to the empirical therapy . METHODS: We established a provisional microbiology laboratory to investigate the suspected outbreak . Blood and spinal fluid specimens were taken from children below the age of seven years with suspected meningitis . The blood and spinal fluid specimens were inoculated in commercial blood culture bottles and locally prepared Thayer-Martin medium in slanted tubes, respectively . The bacterial isolates were sent to Norway for further investigation, including susceptibility testing and pulsed-field gel-electrophoresis (PFGE) . RESULTS: Among 24 children with suspected meningitis and/or septicemia, five neonates had meningitis caused by Salmonella enterica serotype Enteritidis, all of whom died . Two children had S . Enteritidis septicemia without meningitis and both survived . Genotyping with PFGE suggested a clonal outbreak . The salmonella strain was resistant to ampicillin and sensitive to gentamicin, the two drugs commonly used to treat neonatal meningitis at the hospital . CONCLUSION: The investigation reminds us that nontyphoidal salmonellae can cause meningitis associated with very high case-fatality rates . Resistance to multiple antimicrobial agents increases the risk of treatment failure and may have contributed to the fatal outcome in all of the five patients with salmonella meningitis . The investigation indicated that the outbreak was nosocomial and the outbreak subsided after hygienic measures were instituted . Establishing a provisional microbiological laboratory is a valuable and affordable tool to investigate and control outbreaks even in remote rural areas.

J Agric Food Chem, 2004 Sep 22, 52(19), 6042 - 8
Antibacterial activities of plant essential oils and their components against Escherichia coli O157:H7 and Salmonella enterica in apple juice; Friedman M et al.; We evaluated 17 plant essential oils and nine oil compounds for antibacterial activity against the foodborne pathogens Escherichia coli O157:H7 and Salmonella enterica in apple juices in a bactericidal assay in terms of % of the sample that resulted in a 50% decrease in the number of bacteria (BA(50)) . The 10 compounds most active against E . coli (60 min BA(50) range in clear juice, 0.018-0.093%) were carvacrol, oregano oil, geraniol, eugenol, cinnamon leaf oil, citral, clove bud oil, lemongrass oil, cinnamon bark oil, and lemon oil . The corresponding compounds against S . enterica (BA(50) range, 0.0044-0.011%) were Melissa oil, carvacrol, oregano oil, terpeineol, geraniol, lemon oil, citral, lemongrass oil, cinnamon leaf oil, and linalool . The activity (i) was greater for S . enterica than for E . coli, (ii) increased with incubation temperature and storage time, and (iii) was not affected by the acidity of the juices . The antibacterial agents could be divided into two classes: fast-acting and slow-acting . High-performance liquid chromatography analysis showed that the bactericidal results are related to the composition of the oils . These studies provide information about new ways to protect apple juice and other foods against human pathogens.

J Pak Med Assoc, 2004 Jun, 54(6), 295 - 301
Fluroquinolone resistance in typhoidal Salmonella and its detection by nalidixic acid disc diffusion; Anjum P et al.; OBJECTIVE: To determine the presence of fluoroquinolone resistance in Typhoidal salmonellae at Rawalpindi and the role of nalidixic acid in predicting the resistance against fluoroquinolones in Microbiology Laboratory, Department of Pathology, Army Medical College, Rawalpindi . METHODS: One hundred consecutive clinical isolates of Typhoidal salmonellae isolated from blood culture samples were studied . The organisms were identified biochemically and serologically by standard technique . Sensitivity testing was carried out against nalidixic acid and ciprofloxacin by modified Kirby bauer disc diffusion method and minimum inhibitory concentration (MICs) were determined by E-test . RESULTS: Seventeen percent of the isolates were resistant to nalidixic acid . Nalidixic acid disc diffusion and MIC estimation by E-test were 100% comparable . All isolates were sensitive to ciprofloxacin but the isolates which were resistant to nalidixic acid had raised MIC values against ciprofloxacin . CONCLUSION: Typhoidal salmonellae have not shown an overt in vitro resistance against fluoroquinolones in our set up but a significant population has emerged with raised MIC values . Nalidixic acid susceptibility test can be used an indirect evidence of resistance to quinolones.

Clin Chem, 2004 Nov, 50(11), 2136 - 40 Epub 2004 Sep 13.
Genetic predisposition of the interleukin-6 response to inflammation: implications for a variety of major diseases?
Bennermo M, Held C, Stemme S, Ericsson CG, Silveira A, Green F, Tornvall P.
BACKGROUND: A single-nucleotide polymorphism (SNP) in the promoter region of the interleukin-6 (IL-6) gene at position -174 (G>C) has been reported to be associated with a variety of major diseases, such as Alzheimer disease, atherosclerosis, and cardiovascular disease, cancer, non-insulin-dependent diabetes mellitus, osteoporosis, sepsis, and systemic-onset juvenile chronic arthritis . However, authors of previous in vitro and in vivo studies have reported conflicting results regarding the functionality of this polymorphism . We therefore aimed to clarify the role of the -174 SNP for the induction of IL-6 in vivo . METHODS: We vaccinated 20 and 18 healthy individuals homozygous for the -174 C and G alleles, respectively, with 1 mL of Salmonella typhii vaccine . IL-1beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha) were measured in the blood at baseline and up to 24 h after vaccination . RESULTS: Individuals with the G genotype had significantly higher plasma IL-6 values at 6, 8, and 10 h after vaccination than did individuals with the C genotype (P <0.005) . There were no differences between the two genotypes regarding serum concentrations of IL-1beta and TNF-alpha before or after vaccination . CONCLUSIONS: The -174 G>C SNP in the promoter region of the IL-6 gene is functional in vivo with an increased inflammatory response associated with the G allele . Considering the central role of IL-6 in a variety of major diseases, the present finding might be of major relevance.

Clin Chem, 2004 Nov, 50(11), 2037 - 44 Epub 2004 Sep 13.
Reverse transcription-multiplex PCR assay for simultaneous detection of Escherichia coli O157:H7, Vibrio cholerae O1, and Salmonella Typhi; Morin NJ et al.; BACKGROUND: Escherichia coli O157:H7, Vibrio cholerae O1, and Salmonella Typhi are pathogenic bacteria that can be found in contaminated water supplies throughout the world . No currently available assays can simultaneously detect and identify all three pathogens . Our aim was to develop a rapid and reliable technique for simultaneous detection of these pathogens . METHODS: Four unique genes were chosen as the targets of detection . Forward and reverse primers were designed to specifically amplify different sizes of these target genes: a 239-bp region of the E . coli O157 lipopolysaccharide (LPS) gene (rfbE); a 179-bp region of the H7 flagellin gene (fliC); a 419-bp region of the V . cholerae O1 LPS gene (rfbE); and a 329-bp region of Salmonella Typhi LPS gene (tyv) . To ensure the detection of only viable replicating bacteria, RNA was extracted for analysis . After reverse transcription, cDNAs were simultaneously amplified in a single tube by multiplex PCR . The multiplex PCR products were analyzed by gel electrophoresis . To characterize the assay we analyzed, in a blinded fashion, seven unknown RNA samples containing various combinations of total RNA from these bacteria as well as clinical isolates . RESULTS: All seven unknown RNA samples were correctly identified . The assay was able to detect and identify as few as 30 cells of E . coli O157:H7 and Salmonella Typhi in clinical isolates, and the presence of other bacteria did not interfere with the analysis . CONCLUSION: An assay combining reverse transcription with single-tube multiplex PCR was successfully developed and validated for simultaneous detection of viable E . coli O157:H7, V . cholerae O1, and Salmonella Typhi.

Sci Total Environ, 2004 Oct 15, 333(1-3), 209 - 16
Evaluation of the genotoxic, mutagenic and oxidant stress potentials of municipal solid waste incinerator bottom ash leachates; Radetski CM et al.; Triplicate aqueous leachates of a municipal solid waste incineration bottom ash (MSWIBA) were produced according to a European standardised method . Leachates analysis showed relatively low concentrations (less than 1 mg.l(-1)) for four metals (iron, cadmium, lead and copper) . No mutagenic activity was revealed after performing the Salmonella/microsome assay with and without microsomal activation . With the Vicia root tip micronucleus assay, a significant increase in micronucleated cells was observed between 3.4% and 100% leachate concentration . Significant and elevated antioxidant stress enzyme activities, e.g., superoxide dismutase (SOD), catalase (CAT), peroxidase (PER) and glutathione reductase (GR), were detected in Vicia root tissues even at the lowest tested leachate concentration (i.e., 0.3%), whereas this was not always the case in leaf tissues, which showed tissue specificity for the tested enzymes . At the lowest concentration (i.e., 0.3%), a higher increase was observed (respectively 197% and 45% compared to the control) for root glutathione reductase and peroxidase activities over those of other enzymes (superoxide dismutase and catalase) . Our results suggest that MSWIBA aqueous leachates need to be formally tested with genotoxic sensitive tests before recycling and support the hypothesis that plant genotoxicity is related to the cellular production of reactive oxygen species (ROS).

Int J Food Microbiol, 2004 Nov 1, 96(2), 205 - 14
The sequence heterogenicities among 16S rRNA genes of Salmonella serovars and the effects on the specificity of the primers designed; Lin CK et al.; Previously, we have reported a 16S rDNA targeted polymerase chain reaction (PCR) method for the specific detection of Salmonella serovars {J . Appl . Bacteriol . 80 (1996) 659} . The target sites of its primers, i.e . 16SFI and 16SIII, according to the data in GenBank, were found mismatched to the corresponding sequences of some Salmonella serovars, such as those of S . Houten, S . Chingola, S . Bareilly, and S . Weltevreden . Accordingly, a PCR method using a nonspecific primer MINf combined with a primer modified from our 16SFI primer, i.e . the primer MINr, was developed and displayed better detection specificity {Int . J . Food Microbiol . 80 (2003) 67} . In this study, we show the sequence heterogenicity at the primer 16SFI targeting sites for some Salmonella serovars . Thus, the sequence used for designing of PCR primers might be just one of the several possible sequences . Such a situation may lead to the misjudgment on evaluation of the specificity of the primers if this was only based on the data in GenBank . Strains of the above described Salmonella serovars with target sequences from GenBank mismatched to the primer 16SF1 were reidentified and their PCR results were confirmed . Meanwhile, their 16SFI/16SIII primer annealing sites were sequenced and the sequences obtained were found completely and highly homologous to those of 16SFI and complementary to those of 16SIII primer, respectively.

Mutat Res, 2004 Oct 10, 563(2), 107 - 15
Genotoxicity of diphenyl diselenide in bacteria and yeast; Rosa RM et al.; Diphenyl diselenide (DPDS) is an electrophilic reagent used in the synthesis of a variety of pharmacologically active organic selenium compounds . This may increase the risk of human exposure to the chemical at the workplace . We have determined its mutagenic potential in the Salmonella/microsome assay and used the yeast Saccharomyces cerevisiae to assay for putative genotoxicity, recombinogenicity and to determine whether DNA damage produced by DPDS is repairable . Only in exponentially growing cultures was DPDS able to induce frameshift mutations in S . typhimurium and haploid yeast and to increase crossing over and gene conversion frequencies in diploid strains of S . cerevisiae . Thus, DPDS presents a behavior similar to that of an intercalating agent . Mutants defective in excision-resynthesis repair (rad3, rad1), in error-prone repair (rad6) and in recombinational repair (rad52) showed higher than WT-sensitivity to DPDS . It appears that this compound is capable of inducing single and/or double strand breaks in DNA . An epistatic interaction was shown between rad3-e5 and rad52-1 mutant alleles, indicating that excision-resynthesis and strand-break repair may possess common steps in the repair of DNA damage induced by DPDS . DPDS was able to enhance the mutagenesis induced by oxidative mutagens in bacteria . N-acetylcysteine, a glutathione biosynthesis precursor, prevented mutagenesis induced by DPDS in yeast . We have shown that DPDS is a weak mutagen which probably generates DNA strand breaks through both its intercalating action and pro-oxidant effect.

J Mol Graph Model, 2004 Oct, 23(2), 175 - 87
Computational analysis of tyrosine phosphatase inhibitor selectivity for the virulence factors YopH and SptP; Hu X et al.; Bacterial pathogens such as Yersinia and Salmonella represent an important medical concern, causing human diseases ranging from gastrointestinal disease to the plague . The development of novel treatments of these bacterial infections has gained high priority recently due to the emergence of antibiotic resistance in these pathogens and the threat of the use of microbial agents as biological weapons . YopH of Yersinia and SptP of Salmonella are virulence factors that belong to the family of protein tyrosine phosphatases (PTPs) . A great challenge remains in the design of selective PTPs inhibitors due to their highly conserved active site . In this paper, we present a comparative docking study to probe the selective inhibition of YopH and SptP with PTP1B in order to better understand their binding interactions with the bacterial tyrosine phosphates . Characterized binding sites in PTP1B were compared with YopH and SptP . Molecular dynamics simulations were used to incorporate ligand-induced conformational changes in the binding sites . These results, together with those binding modes and binding affinities distinguished in individual PTPs, provide insight into the structure-based design of inhibitors for YopH and SptP.

Gut, 2004 Oct, 53(10), 1424 - 30
Early interactions of Salmonella enterica serovar typhimurium with human small intestinal epithelial explants; Haque A et al.; BACKGROUND: Salmonella enterica serovar typhimurium (S typhimurium) causes invasive gastroenteritis in humans, a disease involving significant penetration of the intestinal mucosa . However, few studies have been undertaken to investigate this interaction directly using differentiated human gut tissue . AIMS: To investigate the early interactions of an enteropathogenic strain of S typhimurium with human intestinal mucosa using human intestinal in vitro organ culture (IVOC) . METHODS: Wild-type and mutant derivatives of S typhimurium TML were used to compare interactions with cultured human epithelial cells, bovine ligated loops, and human intestinal IVOC . RESULTS: S typhimurium TML was shown to attach to cultured Caco-2 brush border expressing cells and cause tissue damage and fluid accumulation in a ligated bovine loop model.S typhimurium TML bound predominantly to the mucus layer of human IVOC explants during the first four hours of IVOC incubation . From four to eight hours of IVOC incubation, small but characteristic foci of attaching and invading S typhimurium TML were detected as clusters of bacteria interacting with enterocytes, although there was no evidence for large scale invasion of explant tissues . Ruffling of enterocyte membranes associated with adherent Salmonella was visualised using electron microscopy . CONCLUSIONS: Human IVOC can be used as an alternative model for monitoring the interactions between S typhimurium and human intestinal epithelium, thus potentially offering insight into the early stages of human Salmonella induced gastroenteritis.

Int J Food Microbiol, 2004 Oct 1, 96(1), 35 - 48
Survival of Escherichia coli O157:H7, O111:H- and O26:H11 in artificially contaminated chocolate and confectionery products; Baylis CL et al.; To date, the survival of Escherichia coli O157:H7 and other verocytotoxin-producing E . coli (VTEC) in chocolate and other confectionery products has not been fully established, unlike Salmonella, which have been responsible for occasional outbreaks of infection linked to contaminated chocolate and related products, although none of these outbreaks have been related to products produced in the United Kingdom . The United Kingdom Biscuit, Cake, Chocolate and Confectionery Alliance commissioned this study to obtain information on the decline and potential survival of E . coli, particularly verocytotoxin-producing strains, in reduced aw confectionery products chocolate, biscuit cream and mallow . These products were artificially contaminated with high (4 log10 cfu/g) and low (2 log10 cfu/g) levels of E . coli O157:H7, O111:H- and O26:H11 and their survival, as affected by storage temperature (10, 22 and 38 degrees C), was monitored over 12 months . Preliminary studies to establish the best inoculation and recovery procedures indicated that differences between counts on selective and non-selective media used were not sufficiently different to influence the outcome of this study . Irrespective of sample type, rapid decline was observed in products stored at 38 degrees C and increased survival occurred in products stored at 10 degrees C . In chocolate (average aw 0.40), these bacteria were detected for up to 43 days in samples stored at 38 degrees C . At 22 degrees C they survived for up to 90 days and in product stored at 10 degrees C they could still be detected after 366 days storage . In biscuit cream (average aw 0.75) they survived for 2 days at 38 degrees C, 42 days at 22 degrees C and 58 days at 10 degrees C . Whilst mallow (aw ca . 0.73) was not stored at 38 degrees C, these bacteria could still be detected in samples stored for up to 113 and 273 days at 22 and 10 degrees C, respectively . The observed prolonged survival of these bacteria under conditions of reduced aw and lowered storage temperature in this study is supported by previous studies with Salmonella and E . coli O157:H7 in other foods . In the same way that Salmonella bacteria can survive for long periods, in excess of 12 months, in chocolate, this study provides evidence that E . coli, including pathogenic strains, can also survive for similar periods of time . Assuming the routes of transmission are similar, controls currently used by the confectionery industry to prevent contamination by Salmonella should also be effective against E . coli, including VT-producing strains, providing that all raw materials have been suitably processed, stored and handled before and during manufacture .

FEMS Microbiol Lett, 2004 Sep 15, 238(2), 333 - 44
Characterization of the second long polar (LP) fimbriae of Escherichia coli O157:H7 and distribution of LP fimbriae in other pathogenic E . coli strains; Torres AG et al.; A second region containing five genes homologous to the long polar fimbrial operon of Salmonella enterica serovar Typhimurium is located in the chromosome of enterohemorrhagic Escherichia coli (EHEC) O157:H7 . A non-fimbriated E . coli K-12 strain carrying the cloned EHEC lpf (lpf2) genes expressed thin fibrillae-like structures on its surface and displayed reduced adherence to tissue culture cells . Neither mutation in the lpfA2 gene in either the parent or lpfA1 mutant strains showed an effect in adherence or in the formation of A/E lesions on HeLa cells . lpfA2 isogenic mutant strains adhere to Caco-2 cells almost as well as the wild-type at 5 h, but they were deficient in adherence at early time points . A collection of diarrheagenic E . coli strains were investigated for the presence of lpfA1 and lpfA2 and results showed that these genes are present in specific serogroups which are phylogenetically related . Our results suggest that LP fimbriae 2 may contribute to the early stages of EHEC adhesion and that genes encoding the major LP fimbrial subunits are present in a small group of EHEC and EPEC serotypes.

Biochem Biophys Res Commun, 2004 Sep 3, 321(4), 828 - 34
STAT3 activation in macrophages following infection with Salmonella; Lin T et al.; The induction of signal transducer and activators of transcription (STATs) in macrophages is necessary for cellular activation, and we investigated the activation of STAT3 in these cells following infection with Salmonella . Increased activation of STAT3 was observed at 6 and 24 h post-infection in the mesenteric lymph nodes and spleens when compared to control mice . CD11b+ cells isolated from the mesenteric lymph nodes of infected mice demonstrated increased STAT3 activation as early as 6 h following infection . Culturing bone marrow-derived macrophages with Salmonella resulted in translocation of STAT3 to the nucleus and STAT3 phosphorylation as early as 30 min post-exposure . Increased STAT3 activation was also observed in the lymphoid organs or in macrophages from mice deficient for IL-6 or IL-10 production following infection . Taken together, these studies clearly demonstrate an early increase in the activation of STAT3 in vivo and in vitro following infection with wild type Salmonella.

Clin Infect Dis, 2004 Aug 15, 39(4), 546 - 51 Epub 2004 Jul 30.
Antimicrobial resistance in nontyphoid Salmonella serotypes: a global challenge; Su LH et al.; Increasing antimicrobial resistance in nontyphoid Salmonella species has been a serious problem for public health worldwide . The high rate of resistance is hampering the use of conventional antibiotics, and growing resistance to newer antimicrobial agents is aggravating the situation . The circumstances of occurrence and spread of antimicrobial resistance are complex; however, a major cause is the widespread use of antimicrobial agents in food animals, particularly in animal feed . Genetic analysis has indicated that the source of resistance is frequently a transferable plasmid . Recent studies have revealed that some serotype-specific virulence plasmids form hybrid plasmids through recombination with resistance plasmids or acquire gene cassettes consisting of multiple resistance genes . Such evolutionary events provide a virulent strain the advantage of survival in an unfavorable drug environment . In view of the serious implications associated with drug-resistant Salmonella species, a more deliberate use of antibiotics in both human medicine and animal industry is warranted . Continued surveillance of antimicrobial resistance and use of antimicrobial agents in food animals is also indispensable.

Clin Infect Dis, 2004 Sep 1, 39(5), 687 - 91 Epub 2004 Aug 09.
Reptile-associated salmonellosis in preschool-aged children in Michigan, January 2001-June 2003; Wells EV et al.; OBJECTIVES: Determine the incidence of reptile-associated salmonellosis in preschool-aged children in Michigan . METHODS: Cases of reptile-associated salmonellosis in children < or =5 years of age occurring in Michigan January 2001-June 2003 were identified through review of individual patient case-history forms provided by local health departments to the Michigan Department of Community Health and by identification of Michigan Department of Community Health laboratory-confirmed cultures of reptile-associated serotypes, determined by evaluation of the Public Health Laboratory Information System's Clinical Nonhuman Salmonella data for 1990-2001 . RESULTS: The incidence of reptile-associated salmonellosis was 11.8% of all Salmonella cases reported in Michigan children aged < or =5 years for the period January 2001 through June 2003 . CONCLUSIONS: Despite the recommendations of the Centers for Disease Control and Prevention to avoid the exposure of children <5 years old to reptiles, reptile-associated salmonellosis in preschool-aged children continues to be a public health problem in Michigan.

Postgrad Med J, 2004 Sep, 80(947), 541 - 5
Salmonella: a continuing problem; Hardy A; Salmonella was the archetypal food poisoning organism of the 20th century . It achieved a high public profile following the salmonella-in-eggs crisis of 1988-89, but by then had been the subject of public health concern and scientific interest for over a century . Early associated with animal foods, the advent of phage typing in the 1940s began to reveal the complexity of its environmental associations . This paper explores the story of salmonella as a continuing problem in epidemiology, microbiology and public health, in the food chain, and in the kitchen.

J Immunol, 2004 Sep 15, 173(6), 4058 - 65
Salmonella escape from antigen presentation can be overcome by targeting bacteria to Fc gamma receptors on dendritic cells; Tobar JA et al.; Dendritic cells (DCs) are professional APCs with the unique ability to activate naive T cells, which is required for initiation of the adaptive immune response against pathogens . Therefore, interfering with DC function would be advantageous for pathogen survival and dissemination . In this study we provide evidence suggesting that Salmonella enterica serovar typhimurium, the causative agent of typhoid disease in the mouse, interferes with DC function . Our results indicate that by avoiding lysosomal degradation, S . typhimurium impairs the ability of DCs to present bacterial Ags on MHC class I and II molecules to T cells . This process could correspond to a novel mechanism developed by this pathogen to evade adaptive immunity . In contrast, when S . typhimurium is targeted to FcgammaRs on DCs by coating bacteria with Salmonella-specific IgG, bacterial Ags are efficiently processed and presented on MHC class I and class II molecules . This enhanced Ag presentation leads to a robust activation of bacteria-specific T cells . Laser confocal microscopy experiments show that virulent S . typhimurium is rerouted to the lysosomal degradation pathway of DCs when internalized through FcgammaR . These observations are supported by electron microscopy studies demonstrating that internalized S . typhimurium shows degradation signs only when coated with IgG and captured by FcgammaRs on DCs . Therefore, our data support a potential role for bacteria-specific IgG on the augmentation of Ag processing and presentation by DCs to T cells during the immune response against intracellular bacteria .

Enferm Infecc Microbiol Clin, 2004 Aug-Sep, 22(7), 381 - 4
{Evaluation of xylose galactosidase (XG) culture medium for the isolation of enteropathogens}; Ruiz G et al.; INTRODUCTION: The chromogenic medium, XG, was evaluated and compared to conventional media for the isolation of Salmonella spp., Shigella spp., Yersinia enterocolitica and Aeromonas spp . METHODS: A total of 1226 human stool samples were inoculated on XG, MacConkey agar, Salmonella-Shigella agar (SS), selenite broth, blood-ampicillin agar and cefsulodin-Irgasan-novobiocin agar (CIN) . RESULTS: The 235 positive cultures included the following: 229 Salmonella spp., 3 Shigella spp., 2 Yersinia enterocolitica and one Aeromonas spp . Among the 229 containing Salmonella spp., 100 were detected on both XG and conventional media and the 129 remaining were detected only on conventional media; recovery of Salmonella spp . on conventional media was significantly higher with respect to XG medium (p < 0.005) . The 3 isolates of Shigella spp . were obtained on XG, the 2 isolates of Yersinia enterocolitica were recovered on CIN agar and the single isolate of Aeromonas spp . was obtained both on XG and blood-ampicillin agar . Colonies suspected to be some of the enteropathogens investigated were present in 791 of the negative stool samples . Among these false-positives 441 (35.9%) were obtained from XG, 142 (11.6%) after selenite enrichment, 132 (10.8%) from MacConkey agar and 76 (6.2%) from SS agar . Most of the false-positive isolates obtained on XG medium were consistent with Salmonella spp . (n = 408) . CONCLUSIONS: XG chromogenic medium showed low sensitivity (64%) and specificity (69%) for the detection of Salmonella spp . Recovery of Shigella spp . on XG medium in three samples may have been due to the immediate processing of the samples . We conclude that XG chromogenic medium can not be recommended as an alternative to currently used conventional media.

Lett Appl Microbiol, 2004, 39(4), 319 - 25
Antibacterial effect of crude water-soluble arrowroot (Puerariae radix) tea extracts on food-borne pathogens in liquid medium; Kim S et al.; AIMS: To evaluate the effect of crude water-soluble arrowroot tea extracts on microbial growth of food-borne pathogens in liquid medium and to confirm the damage to bacterial cells using Transmission Electronic Microscopy (TEM) . METHODS AND RESULTS: Inhibition of growth of Escherichia coli O157:H7, Salmonella enterica serovar Enteritidis, Listeria monocytogenes and Staphylococcus aureus was investigated using Brain Heart Infusion (BHI) broth containing 0 (control), 0.63, 1.25, 2.5 and 5.0% (w/v) arrowroot tea . Bacterial cell counts were performed on specific selective agar on days 0, 1, 3 and 5 . BHI containing 5.0% arrowroot tea extract showed a 6-7 log suppression of growth for all test strains on days 3 and 5, compared with the control . Even 0.63% arrowroot tea effectively inhibited microbial growth of all test strains on day 5 . TEM images of the samples treated with 5.0% arrowroot tea revealed the rupture of cell walls and nonhomogeneous disposition of cytoplasmic materials within treated bacteria . CONCLUSIONS: Crude water-soluble arrowroot tea extract strongly inhibited microbial growth of all test pathogens in liquid medium . SIGNIFICANCE AND IMPACT OF THE STUDY: Water-soluble arrowroot tea extract has the potential to be used directly on foods or as a spray on the surfaces of food handling and processing facilities in order to prevent microbial growth of both Gram-negative and Gram-positive bacteria.

Front Biosci, 2004 Sep 01, 9, 3209 - 17
The role of tachykinins on bacterial infections; Pascual DW; Tachykinins represent a family of neuropeptides sharing similar C-terminus sequences, but exhibiting preferential binding to one of three receptors called neurokinin receptors (NK-R) . While known for its role in contracting smooth muscle or acting as a pain signal neurotransmitter, substance P (SP) and other tachykinins can directly influence immune responses . Studies from the early 1980s revealed that human lymphocytes bore NK-R, but it remains unclear, even to-date, why such receptors are expressed on leukocytes . Nerve tracing studies have provided some speculation that the nervous system can assist the immune system in stimulating an immune response dependent upon which neuropeptide-bearing fibers infiltrate specific lymphoid structures . Such observations have important implications for regulating mucosal responses given that tachykinin-bearing nerve fibers extensively innervate the gut, and SP concentrations in the gut are second only to the brain . Such evidence suggests that SP and related neuropeptides may be important in controlling bacterial infections of the gut . This is shown by blocking SP action in which mice show increased susceptibility to Salmonella infections since induction of IFN-gamma is significantly reduced . In addition, the absence or its presence of SP's or the newly discovered lymphocyte-derived neurokinin called hemokinin's action can modify host IgA responses . Thus, tachykinins introduce new circuits to immune regulation suggesting that these neuropeptides exhibit cytokine- and chemokine-like action.

Environ Sci Technol, 2004 Aug 1, 38(15), 4140 - 8
Do arsenosugars pose a risk to human health? The comparative toxicities of a trivalent and pentavalent arsenosugar; Andrewes P et al.; Seafood frequently contains high concentrations of arsenic (approximately 10-100 mg/kg dry weight) . In marine algae (seaweed), this arsenic occurs predominantly as ribose derivatives known collectively as arsenosugars . Although it is clear that arsenosugars are not acutely toxic, there is a possibility of arsenosugars having slight chronic toxicity . In general, trivalent arsenicals are more toxic than their pentavalent counterparts, so in this work we examine the hypothesis that trivalent arsenosugars might be significantly more toxic than pentavalent arsenosugars in vitro . We compared the in vitro toxicity of (R)-2,3-dihydroxypropyl-5-deoxy-5-dimethylarsinoyl-beta-D-riboside, a pentavalent arsenosugar, to that of its trivalent counterpart, (R)-2,3-dihydroxypropyl-5-deoxy-5-dimethylarsino-beta-D-riboside . The trivalent arsenosugar nicked plasmid DNA, whereas the pentavalent arsenosugar did not . The trivalent arsenosugar was more cytotoxic (IC50 = 200 microM, 48 h exposure) than its pentavalent counterpart (IC50 > 6000 microM, 48 h exposure) in normal human epidermal keratinocytes in vitro as determined via the neutral red uptake assay . However, both the trivalent and the pentavalent arsenosugars were significantly less toxic than MMA(III), DMA(III), and arsenate . Neither the pentavalent arsenosugar nor the trivalent arsenosugar were mutagenic in Salmonella TA104 . The trivalent arsenosugar was readily formed by reaction of the pentavalent arsenosugar with thiol compounds, including, cysteine, glutathione, and dithioerythritol . This work suggests that the reduction of pentavalent arsenosugars to trivalent arsenosugars in biology might have environmental consequences, especially because seaweed consumption is a significant environmental source for human exposure to arsenicals.

Vet Immunol Immunopathol, 2004 Oct, 101(3-4), 251 - 7
Salmonella enteritidis clearance and immune responses in chickens following Salmonella vaccination and challenge; Babu U et al.; Our previous work showed that the cell-mediated immunity (CMI) was enhanced by live Salmonella vaccine (LV) . The objective of this study was to evaluate the impact of live and killed Salmonella vaccines on Salmonella enteritidis (SE) clearance and to determine if the clearance was mediated by cell-mediated and/or humoral immunity . Chickens were first immunized at 2 weeks of age followed by a booster dose at 4 weeks, challenged with live SE 2 weeks later (6-week-old) and tested for CMI, antibody response and SE clearance 1-week post SE-challenge (7-week-old) . Spleen cell proliferation induced by SE-flagella and Concanavalin A (Con A) were significantly higher and SE shedding was significantly lower in the LV group . The splenic CD3 population was significantly lower and B cells were higher in the control group compared to all the SE-challenged groups (with and without vaccination) . Serum antibody to SE-flagella and envelope were significantly higher in the KV group compared to all the other groups . These results suggest that LV protects against SE infection, probably by enhancing the CMI.

Indian J Med Res, 2004 Aug, 120(2), 111 - 4
Current pattern in antimicrobial susceptibility of Salmonella Typhi isolates in Pondicherry; Madhulika U et al.; Typhoid fever continues to remain a health problem as the causative organism Salmonella Typhi has developed resistance to many of the antibiotics used . This study was undertaken to determine the current pattern of resistance to antimicrobial agents and phage types of S.Typhi isolates obtained in a tertiary health care hospital in Pondicherry . Blood culture was done for 1296 suspected cases of enteric fever and 157 strains of S . Typhi were isolated . Sensitivity to ampicillin, chloramphenicol, gentamicin, ciprofloxacin and ceftriaxone was determined by disc diffusion, and the minimum inhibitory concentration (MIC) of ciprofloxacin determined . There were 61 multidrug resistant (MDR) isolates . The MIC of ciprofloxacin for 147 isolates was >0.5 mg/l; of these, 131 were resistant to nalidixic acid . Phage typing was done for 123 isolates and 115 were found to be of phage type E1, biotype 1 . A decline in the number of MDR isolates was noted . Concurrently, there has been an increase in the number of isolates sensitive to all antibiotics except nalidixic acid, and all these isolates showed reduced susceptibility to ciprofloxacin . Nalidixic acid susceptibility could be a useful screening test for the detection of decreased susceptibility of S . Typhi to ciprofloxacin . The clinicians should be advised to use ceftriaxone selectively in cases showing non-responsiveness to ciprofloxacin.

Appl Environ Microbiol, 2004 Sep, 70(9), 5305 - 14
Phenotypic and molecular typing of Salmonella strains reveals different contamination sources in two commercial pig slaughterhouses; Botteldoorn N et al.; This study aimed to define the origin of Salmonella contamination on swine carcasses and the distribution of Salmonella serotypes in two commercial slaughterhouses during normal activity . Salmonellae were isolated from carcasses, from colons and mesenteric lymph nodes of individual pigs, and from the slaughterhouse environment . All strains were serotyped; Salmonella enterica serotype Typhimurium and Salmonella enterica serotype Derby isolates were additionally typed beyond the serotype level by pulsed-field gel electrophoresis (PFGE) and antibiotic resistance profiling (ARP); and a subset of 31 serotype Typhimurium strains were additionally phage typed . PFGE and ARP had the same discriminative possibility . Phage typing in combination with PFGE could give extra information for some strains . In one slaughterhouse, 21% of the carcasses were contaminated, reflecting a correlation with the delivery of infected pigs . Carcass contamination did not result only from infection of the corresponding pig; only 25% of the positive carcasses were contaminated with the same serotype or genotype found in the corresponding feces or mesenteric lymph nodes . In the other slaughterhouse, 70% of the carcasses were contaminated, and only in 4% was the same genotype or serotype detected as in the feces of the corresponding pigs . The other positive carcasses in both slaughterhouses were contaminated by genotypes present in the feces or lymph nodes of pigs slaughtered earlier that day or from dispersed sources in the environment . In slaughterhouses, complex contamination cycles may be present, resulting in the isolation of many different genotypes circulating in the environment due to the supply of positive animals and in the contamination of carcasses, probably through aerosols.

BMC Med . 2004 Sep 2;2(1):32.
Emergence of new Salmonella Enteritidis phage types in Europe? Surveillance of infections in returning travellers; Nygard K et al.; BACKGROUND: Among human Salmonella Enteritidis infections, phage type 4 has been the dominant phage type in most countries in Western Europe during the last years . This is reflected in Salmonella infections among Swedish travellers returning from abroad . However, there are differences in phage type distribution between the countries, and this has also changed over time . METHODS: We used data from the Swedish infectious disease register and the national reference laboratory to describe phage type distribution of Salmonella Enteritidis infections in Swedish travellers from 1997 to 2002, and have compared this with national studies conducted in the countries visited . RESULTS: Infections among Swedish travellers correlate well with national studies conducted in the countries visited . In 2001 a change in phage type distribution in S . Enteritidis infections among Swedish travellers returning from some countries in southern Europe was observed, and a previously rare phage type (PT 14b) became one of the most commonly diagnosed that year, continuing into 2002 and 2003 . CONCLUSIONS: Surveillance of infections among returning travellers can be helpful in detecting emerging infections and outbreaks in tourist destinations . The information needs to be communicated rapidly to all affected countries in order to expedite the implementation of appropriate investigations and preventive measures.

Biochem J, 2005 Jan 1, 385(Pt 1), 135 - 43
Enhancement of endotoxin neutralization by coupling of a C12-alkyl chain to a lactoferricin-derived peptide; Andra J et al.; Antibacterial peptide acylation, which mimics the structure of the natural lipopeptide polymyxin B, increases antimicrobial and endotoxin-neutralizing activities . The interaction of the lactoferricin-derived peptide LF11 and its N-terminally acylated analogue, lauryl-LF11, with different chemotypes of bacterial lipopolysaccharide (LPS Re, Ra and smooth S form) was investigated by biophysical means and was related to the peptides' biological activities . Both peptides exhibit high antibacterial activity against the three strains of Salmonella enterica differing in the LPS chemotype . Lauryl-LF11 has one order of magnitude higher activity against Re-type, but activity against Ra- and S-type bacteria is comparable with that of LF11 . The alkyl derivative peptide lauryl-LF11 shows a much stronger inhibition of the LPS-induced cytokine induction in human mononuclear cells than LF11 . Although peptide-LPS interaction is essentially of electrostatic nature, the lauryl-modified peptide displays a strong hydrophobic component . Such a feature might then explain the fact that saturation of the peptide binding takes place at a much lower peptide/LPS ratio for LF11 than for lauryl-LF11, and that an overcompensation of the negative LPS backbone charges is observed for lauryl-LF11 . The influence of LF11 on the gel-to-liquid-crystalline phase-transition of LPS is negligible for LPS Re, but clearly fluidizing for LPS Ra . In contrast, lauryl-LF11 causes a cholesterol-like effect in the two chemotypes, fluidizing in the gel and rigidifying of the hydrocarbon chains in the liquid-crystalline phase . Both peptides convert the mixed unilamellar/non-lamellar aggregate structure of lipid A, the 'endotoxic principle' of LPS, into a multilamellar one . These data contribute to the understanding of the mechanisms of the peptide-mediated neutralization of endotoxin and effect of lipid modification of peptides.

J Am Vet Med Assoc, 2004 Aug 15, 225(4), 574 - 7
Isolation of Salmonella spp from the environment of dairies without any history of clinical salmonellosis; Peek SE et al.; OBJECTIVE: To determine whether Salmonella spp could be isolated from the environment of free stall dairies in Wisconsin without any history of clinical salmonellosis and determine the serotype and antimicrobial susceptibility of any Salmonella isolates recovered from the environment . DESIGN: Cross-sectional study . STUDY POPULATION: 20 free stall dairies with no history of clinical salmonellosis . PROCEDURES: Dairy owners completed a questionnaire regarding management and production practices . Multiple swab samples were obtained from throughout the free stall facilities and submitted for bacterial culture for Salmonella spp . Odds ratios were calculated to compare herd-level risk factors between dairies from which Salmonella organisms were isolated and herds from which Salmonella organisms were not isolated . RESULTS: Salmonella organisms were isolated from 9 of the 20 (45%) dairies . Salmonella serotype Meleagridis was isolated from 4 dairies, S . Meleagridis and S . Kentucky were isolated from 2 dairies, S . Meleagridis and S . Cyprus were isolated from 1 dairy, S . Cerro was isolated from 1 dairy, and S . Corvallis was isolated from 1 dairy . All isolates were susceptible to all antimicrobial agents tested . None of the potential risk factors analyzed demonstrated a significant association with an increased likelihood of isolating Salmonella spp . CONCLUSIONS AND CLINICAL RELEVANCE: Environmental Salmonella contamination was demonstrated on free stall dairies with no history of clinical salmonellosis.

Hum Pathol, 2004 Sep, 35(9), 1112 - 20
Surgical pathology of infected aneurysms of the descending thoracic and abdominal aorta: clinicopathologic correlations in 29 cases (1976 to 1999); Miller DV et al.; Infected aortic aneurysms are uncommon, and only rarely have their surgical pathological features been described . Clinical and histopathologic features were evaluated in patients undergoing surgical repair of infected aneurysms of the descending thoracic or abdominal aorta over a 24-year period . Findings were compared with observations (primarily from autopsy studies) from the previous 25-year period (1950 to 1975) and other more recent reports . Of the 29 patients in our study, 79% were men, 90% had risk factors for atherosclerosis, and 72% had an identifiable risk or source of infection . Fever was present in 76%, and abdominal or back pain was seen in 66% . Among the 20 cases with an identifiable causative organism, staphylococcus accounted for 30%, streptococcus for 20%, salmonella for 20%, Escherichia coli for 15%, and other organisms for 15% . Aneurysms were saccular in 59% and infrarenal in 42%, and had a mean diameter of 5.6 cm . Microscopically, 6 patterns were recognized: acute inflammation superimposed on severe chronic atherosclerosis (55%), atherosclerosis with chronic inflammation (20%), acute inflammation without atherosclerosis (7%), chronic adventitial inflammation (7%), pseudoaneurysm formation (7%), and necrotizing granulomatous inflammation (4%) . Special stains for organisms were positive in only 38% of the cases . Pathological findings of this series of surgical specimens spanning the fourth quarter of the twentieth century were not appreciably different from those described in autopsy series from the preceding years, although the causative microorganisms and agents used to treat them, preoperative diagnostic modalities, and surgical approaches have evolved.

BMC Public Health . 2004 Sep 01;4(1):40.
An outbreak of Salmonella enteritidis phage type 34a infection associated with a Chinese restaurant in Suffolk, United Kingdom; Badrinath P et al.; BACKGROUND: On 30th July 2002, the Suffolk Communicable Disease Control Team received notifications of gastrointestinal illness due to Salmonella Enteritidis in subjects who had eaten food from a Chinese restaurant on 27th July . An Outbreak Control Team was formed resulting in extensive epidemiological, microbiological and environmental investigations . METHODS: Attempts were made to contact everybody who ate food from the restaurant on 27th July and a standard case definition was adopted . Using a pre-designed proforma information was gathered from both sick and well subjects . Food specific attack rates were calculated and two-tailed Fisher's exact test was used to test the difference between type of food consumed and the health status . Using a retrospective cohort design univariate Relative Risks and 95% Confidence Intervals were calculated for specific food items . RESULTS: Data was gathered on 52 people of whom 38 developed gastrointestinal symptoms; 16 male and 22 female . The mean age was 27 years . The mean incubation period was 30 hours with a range of 6 to 90 hours . Food attack rates were significantly higher for egg, special and chicken fried rice . Relative risk and the Confidence interval for these food items were 1.97 (1.11-3.48), 1.56 (1.23-1.97) and 1.48 (1.20-1.83) respectively . Interviews with the chef revealed that many eggs were used in the preparation of egg-fried rice, which was left at room temperature for seven hours and was used in the preparation of the other two rice dishes . Of the 31 submitted stool specimens 28 tested positive for S Enteritidis phage type 34a and one for S Enteritidis phage type 4 . CONCLUSION: In the absence of left over food available for microbiological examination, epidemiological investigation strongly suggested the eggs used in the preparation of the egg-fried rice as the vehicle for this outbreak . This investigation highlights the importance of safe practices in cooking and handling of eggs in restaurants.

J Microbiol Immunol Infect, 2004 Aug, 37(4), 203 - 7
Cloning, sequencing and expression of GroEL-like protein gene of Vibrio parahaemolyticus; Wong HC et al.; Vibrio parahaemolyticus is an important enteropathogen in regions where much seafood is consumed . Substantial quantity of GroEL-like protein is produced during the heat shock of V . parahaemolyticus and located in periplasmic and extracellular fractions . In this study, the GroEL-like protein gene of this pathogen was cloned and sequenced and its properties were analyzed . The open reading frame consisted of 1647 bp, encoded a 57.6-kDa GroEL-like protein of 548 amino acids . The amino acid sequence, hydrophobicity and antigenic pattern of V . parahaemolyticus GroEL-like protein were similar to the GroEL proteins of other vibrios, Escherichia coli and Salmonella enterica Typhi . The groEL-like gene of V . parahaemolyticus was cloned into the pQE-30 expression vector and the expression of a His-tagged GroEL-like protein was rapidly induced by isopropyl-beta-D-thiogalactopyranoside, largely in an insoluble form . The results of this study facilitate the study of the functions of the GroEL-like protein of V . parahaemolyticus.

Poult Sci, 2004 Aug, 83(8), 1276 - 86
Comparison of zinc acetate and propionate addition on gastrointestinal tract fermentation and susceptibility of laying hens to Salmonella enteritidis during forced molt; Moore RW et al.; Feed deprivation is the most common method used to induce molting and stimulate multiple egg-laying cycles in laying hens for commercial egg production . Unfortunately, an increased risk of Salmonella enteritidis (SE) colonization may result from the use of this method . Methods to stimulate multiple egg-laying cycles without increasing the risk of SE are needed . In each of 3 experiments, hens over 50 wk of age were divided into groups of 12 and placed in individual laying cages . One week before dietary changes, hens were put on an 8L:16D photoperiod that continued for the 9-d experimental period . Hens in all treatments were challenged orally with 10(4) cfu of SE on the fourth day . Treatments were full fed hens (nonmolted, NM), nonfed hens (molted, M), a zinc acetate diet (ZAC), and a zinc propionate diet (ZPR) . The zinc diets contained 10,000 mg of zinc per kilogram of diet . Body weight losses were significantly higher in the M, ZPR, and ZAC treatments than in the NM treatment . Crop lactic acid decreased more in M, ZPR, and ZAC treatments than in NM hens in trial 2 . Crop pH was significantly (P < 0.05) lower in NM hens than in M, ZAC, and ZPR hens in trial 2 . Although cecal individual or total volatile fatty acids (VFA), and lactic acid were not significantly (P > 0.05) different between NM hens and M, ZAC and ZPR hens in trial 1, lactic acid was significantly (P < 0.05) higher in NM hens than in M, ZAC and ZPR hens (trial 2), and cecal total VFA were lower in M hens than in NM, ZAC and ZPR hens (trial 3) . Colonization of SE in the crop and ceca was higher in the M and ZPR hens (trials 1 and 2) . Liver, spleen, or ovary invasion by SE was higher in the M and ZPR hens (trials 1 and 2) than in NM hens . At the zinc concentration used in these studies, the zinc dietary regimens may be effective for reducing the risk of SE during induced molt.

Medicina (B Aires), 2004, 64(4), 340 - 2
{Purulent pericarditis with pericardial tamponade caused by Streptococcus agalactiae and Salmonella enterica no typhi}; Arruvito L et al.; Purulent pericarditis (PP) is an uncommon condition with high mortality . In the preantibiotic period, Staphyloccocus aureus and Streptococcus pneumoniae were the most common etiologic agents . We describe the case of a 75-year old man with septic shock, PP and cardiac tamponade caused by Streptococcus agalactiae and Salmonella enterica no-typhi . To our knowledge this association of pathogenic organisms has not been previously reported in the literature . The pathogenesis is here reviewed, and in our patient presumably, purulent pericarditis occurred via hematogeneus spread undergoing upper gastrointestinal endoscopy . The patient's course was complicated and he died on 34th hospital day . After this case report it is considered that differential etiologic diagnosis of PP should include these agents, especially in immunodepressed patients with predisposing factors.

Ann Thorac Surg, 2004 Sep, 78(3), 767 - 72; discussion 767-72
Results of aortic valve-sparing operations: experience with remodeling and reimplantation procedures in 65 patients; Bethea BT et al.; BACKGROUND: Valve-sparing operations for aortic root aneurysms are increasing in frequency, but techniques and results are still in evolution . We reviewed our experience with 65 patients (adults and children) who had this operation at our institution to determine early and late outcomes . METHODS: A retrospective clinical review was undertaken using hospital records, clinical and echocardiographic, computed tomography, magnetic resonance imaging data, and telephone interviews with patients and their physicians . RESULTS: Between July 1994 and December 2002, 65 patients (46 adults and 19 children) underwent a valve-sparing operation for aortic root aneurysm . Forty-four of the patients had the Marfan syndrome; the remaining 21 had either a nonspecific connective tissue disorder (14 patients) or a miscellaneous disease process such as Ehlers-Danlos syndrome (7 patients) . Fifty-eight (89%) had a David II (remodeling) procedure and 7 had a David I (reimplantation) procedure . The DePaulis "Valsalva graft" was used in six of the David I patients . There were no operative or hospital deaths; only one late death occurred in an adult due to salmonella meningitis . Overall, survival was 100% at one year and 98% at 3 and 5 years . Ten patients (7 adults and 3 children) developed significant late aortic insufficiency (AI) . Nine of these patients had a David II procedure and in 8 of these cases, AI was secondary to significant late annular dilatation . One of the 10 patients developed late AI 8.2 years after a David I procedure; his AI was secondary to aortic leaflet extension and prolapse . Six of the 10 patients who developed significant late AI required aortic valve replacement (4 adults and 2 children) . Freedom from late aortic valve replacement (AVR) in this series of 65 patients was 91% at 3 and 84% at 5 years . At the close of this study, 58 patients were New York Heart Association (NYHA) class I and 6 were NYHA class II; no patients were class III or IV . There were no episodes of endocarditis or clinically significant thromboembolism . CONCLUSIONS: Valve-sparing operations provide satisfactory results for many patients with an aortic root aneurysm, but the David II remodeling procedure has a greater risk of late annular dilatation and AI . The David I reimplantation procedure utilizing the DePaulis Valsalva graft may obviate this problem.

FEMS Microbiol Lett, 2004 Sep 1, 238(1), 267 - 72
Role of an acrR mutation in multidrug resistance of in vitro-selected fluoroquinolone-resistant mutants of Salmonella enterica serovar Typhimurium; Olliver A et al.; Quinolone resistance in Salmonella spp . is usually attributed to both active efflux and mutations leading to modification of the target enzymes DNA gyrase and topoisomerase IV . Here, we investigated the presence of mutations in the efflux regulatory genes of fluoroquinolone- and multidrug-resistant mutants of Salmonella enterica serovar Typhimurium (S . Typhimurium) selected in vitro with enrofloxacin that both carried a mutation in the target gene gyrA and overproduced the AcrAB efflux pump . No mutations were detected in the global regulatory loci marRAB and soxRS for the four strains studied . A mutation in acrR, the local repressor of acrAB, was found for two ciprofloxacin-resistant selected-mutants, leading to duplication of amino acids Ile75 and Glu76 . Complementation experiments with wild-type acrR showed that the mutation identified in acrR partially contributed to the increase in resistance levels to several unrelated antibiotics . The acrR mutation also contributed to acrAB overexpression as shown by RT-PCR . Thus, this study underlines the role of an acrR mutation, in addition to the mutation in gyrA, in the fluoroquinolone and multidrug resistance phenotype of S . Typhimurium mutants, through overexpression of acrAB.

FEMS Microbiol Lett, 2004 Sep 1, 238(1), 227 - 33
Identification of nucleotides critical for activity of the sigmaE-dependent rpoEp3 promoter in Salmonella enterica serovar Typhimurium; Miticka H et al.; We previously described a two-plasmid system for the identification of promoters recognized by Salmonella enterica serovar Typhimurium (S . Typhimurium) sigmaE . The S . Typhimurium sigmaE-dependent rpoEp3 promoter was active in the E . coli two-plasmid system only after arabinose-induced expression of S . Typhimurium rpoE . In the present study, we have exploited this two-plasmid system for the identification of nucleotides critical for activity of the rpoEp3 promoter . A library of randomly mutated DNA fragments containing the rpoEp3 promoter was cloned upstream of a lacZalpha reporter gene and screened for activity in the presence of S . Typhimurium sigmaE . The clones exhibiting reduced LacZ activity were sequenced to identify the mutations . The activity of the mutated rpoEp3 promoters were studied further using a luciferase-based promoter-probe plasmid . All of the important nucleotides of the rpoEp3 promoter (in capital) were located in the -35 (ggAActt) and -10 (TctaA) regions . The critical nucleotides were also the most conserved in known sigmaE-dependent promoters . The study also revealed the importance of the 16-bp spacing between -10 and -35 region, as reducing the spacing to 15-bp greatly reduced activity of the promoter . This method should be generally applicable for the identification of important nucleotides in the cognate promoters of other sigma factors.

J Chemother, 2004 Aug, 16(4), 337 - 42
Molecular characterization of beta-lactam resistance of Salmonella isolates from pediatric patients in Romania; Filip R et al.; The molecular characterization of 16 clinical isolates of Salmonella enterica (14 serotype Typhimurium and 2 serotype Kingston) obtained between January and June 1999 from feces of children hospitalized in Iasi, Romania were genotypically compared by pulse field gel electrophoresis of XbaI restricted bacterial DNA . The majority of the clinical isolates (12/16) belonged to cluster A and (4/16) to unrelated strains, correlating to the OMP profile . Two major different patterns of beta-lactamases were identified: the first with pI of 5.4, 8.2 in 6/16 strains and the second with pI of 5.4 in 5/16 . The blaTEM beta-lactamase was identified in 14/16 of the clinical isolates and the blaSHV-5 gene in one strain . We concluded that extended spectrum beta-lactamase (ESBL) with pIs of 8.2 was the most frequent enzyme produced by serotype Typhimurium isolates which were related.

J Food Prot, 2004 Aug, 67(8), 1751 - 4
Incubation of egg contents pools at an elevated temperature (42 degrees C) does not improve the rapid detection of Salmonella enteritidis phage type 14b; Gast RK et al.; Detecting internal Salmonella Enteritidis (SE) contamination in eggs is essential for protecting public health . Pooling together > or = 10 eggs for sampling allows many eggs to be screened for contamination, but such pools must be incubated (usually at 25 to 37 degrees C) to permit small numbers of SE to multiply before further testing . The present study determined whether incubating egg contents pools at an elevated temperature (42 degrees C) could increase the rate of multiplication of a phage type 14b strain of SE sufficiently to support the detection of contamination by a rapid lateral flow immunodiffusion method within a single day . Pools of 10 eggs were contaminated with approximately 10 CFU of SE, supplemented with concentrated broth enrichment medium, and incubated at either 37 or 42 degrees C . Incubation of contaminated egg pools at 42 degrees C resulted in significantly higher SE levels after 6, 8, 10, and 12 h . However, incubation at 42 degrees C could only generate a mean log SE concentration of 4.21 CFU/ml within a single working day (8 h), inadequate to support efficient detection by most rapid assays . Detection of SE contamination in egg pools by a rapid lateral flow immunodiffusion test was not achieved at a high frequency until 12 h of incubation at 42 degrees C.

J Food Prot, 2004 Aug, 67(8), 1666 - 70
Thermal resistance of Listeria monocytogenes, Salmonella Heidelberg, and Escherichia coli O157:H7 at elevated temperatures; Huang L; A continuous-flow apparatus was developed to measure thermal resistance (D- and z-values) of microorganisms at temperatures above 65 degrees C . This apparatus was designed to test whether vegetative microorganisms exhibited unusually high thermal resistance that prevented them from being completely eliminated at temperatures applicable to vacuum-steam-vacuum processes (116 to 157 degrees C) . The apparatus was composed of a high-pressure liquid chromatography pump, a heating unit, and a cooling unit . It was designed to measure small D-values (<1 s) . Three randomly selected organisms, Listeria monocytogenes, Salmonella Heidelberg, and Escherichia coli O157:H7 suspended in deionized water were tested in the continuous-flow apparatus at temperatures ranging from 60 to 80 degrees C . Studies showed that the D-values of these organisms ranged from 0.05 to 20 s . Heating at 80 degrees C was found to be basically the physical limit of the system . Experimental results showed that L . monocytogenes, Salmonella Heidelberg, and E . coli O157:H7 did not exhibit unusual heat resistance . The conditions used in the vacuum-steam-vacuum processes should have completely inactivated organisms such as L . monocytogenes, Salmonella Heidelberg, and E . coli O157:H7 if present on food surfaces . The complete destruction of bacteria during vacuum-steam-vacuum processes might not occur because the surface temperatures never reached those of the steam temperatures and because bacteria might be hidden beneath the surface and was thus never exposed to the destructive effects of the steam.

J Food Prot, 2004 Aug, 67(8), 1624 - 9
Microbial contamination of carcasses, meat, and equipment from an Iberian pork cutting plant; Pala TR et al.; An assessment and follow-up of the microbial contamination of an Iberian pork cutting room is presented . Samples were taken from carcasses (n = 76), meat pieces (three types, n = 71), meat for dry-cured sausages (3 types, n = 66), and surfaces of equipment (n = 158) . Aerobic plate counts (APC) at 37 degrees C on meat pieces (primal cuts) were lower than on carcasses (3.62 log CFU/10 cm2 against 4.63 log CFU/10 cm2), probably owing to the removal of the skin . However, more than 80% of the meat pieces showed presence of Escherichia coli . For the three types of meat intended for dry-cured sausages, higher counts (P < 0.001) were found for meat type 3--an important cut obtained from the vertebral column--at 2.62 log CFU/g for E . coli; the particular surface used in the handling of meat type 3 also showed high counts (P < 0.001) for E . coli . Consequently, attention should be paid to the hazard analysis critical control point plan at this stage . Salmonella was isolated from 3.94% of the carcass surfaces (perianal zone), 4.46% of meat pieces, and 13.58% of meat for dry-cured sausages . Moreover, the percentages for isolation of Salmonella from carcasses of Iberian pigs (extensive rearing) in our study were lower than those generally reported in the literature for "white pigs" (intensive rearing) . Coagulase-positive Staphylococcus aureus was isolated in 31.82% of meat samples for dry-cured sausages, in 16.90% of meat pieces, and in 15.50% of the equipment after 4 h of work . Of the coagulase-positive strains isolated, 47.61% were producers of enterotoxin.

J Food Prot, 2004 Aug, 67(8), 1585 - 90
AnDiaTec Salmonella sp . PCR-ELISA for analysis of food samples; Metzger-Boddien C et al.; A commercially available PCR kit (AnDiaTec Salmonella sp . PCR-ELISA) was developed and evaluated for the detection of Salmonella sp . in food samples . The test is based on PCR amplification and hybridization of the amplified DNA to a microtiter plate followed by the detection of PCR product in the manner of an enzyme-linked immunosorbent assay test . The sensitivity and specificity were evaluated first with Salmonella pure cultures and artificially contaminated food samples, including food types for which an inhibition of the PCR reaction was expected . Both experiments proved a very good sensitivity, specificity, and reliability of the test with a very broad range of food types . In a second evaluation study, more than 1,100 food samples of different types were tested in parallel with the PCR method and with the International Standardization Organization 6579 bacteriological reference method . The results of this evaluation study and the results from other experiments on dilutions of artificially contaminated food samples led to the establishment of a positive-negative cutoff value (optical density at 450 nm of more than 0.9) with respect to the conventional bacteriological method . Using this positive-negative cutoff, 98% agreement to the bacteriological method was obtained.

J Food Prot, 2004 Aug, 67(8), 1578 - 84
Potential for internalization, growth, and survival of Salmonella and Escherichia coli O157:H7 in oranges; Eblen BS et al.; Internalization potential, survival, and growth of human pathogens within oranges were investigated in a series of laboratory experiments . Submerging oranges into dye solutions at various temperature differentials was used to assess internalization potential . Conditions in which dye internalization was observed were further studied by applying Escherichia coli O157:H7 or Salmonella onto the stem scar, subjecting the oranges to a temperature differential, juicing, and measuring numbers of pathogens in the resulting juice . Pathogens for growth and survival studies were applied to or injected into simulated peel punctures . Oranges with small peel holes of selected sizes were also placed into solutions containing these pathogens . Bacterial survival was also evaluated in orange juice at 4 and 24 degrees C . Oranges internalized pathogens at a frequency of 2.5 to 3.0%, which mirrored dye internalization frequency (3.3%) . Pathogens were internalized at an uptake level of 0.1 to 0.01% of the challenge applied . Bacteria grew within oranges at 24 degrees C, but not at 4 degrees C . Thirty-one percent of oranges with 0.91-mm surface holes showed pathogen uptake, whereas 2% of oranges with 0.68-mm holes showed pathogen uptake . Pathogens added to fresh orange juice and incubated at 24 degrees C declined 1 log CFU/ml within 3 days . These results suggest that internalization, survival, and growth of human bacterial pathogens can occur within oranges intended for producing unpasteurized juice.

J Dairy Sci, 2004 Jul, 87(7), 2177 - 83
Destruction of Mycobacterium paratuberculosis, Salmonella spp., and Mycoplasma spp . in raw milk by a commercial on-farm high-temperature, short-time pasteurizer; Stabel JR et al.; The 2002 NAHM's Dairy Survey indicated that 87.2% of dairy farms in the United States feed waste milk to their neonatal calves . Although cost-effective, this practice can lead to increased calf morbidity and mortality due to ingestion of pathogenic agents . In an effort to reduce the risk of infection, dairy producers are implementing on-farm pasteurization of the waste milk as a control procedure before feeding the milk to calves . In the present study, the efficacy of a commercial high-temperature, short-time (HTST) on-farm pasteurizer unit to destroy Mycobacterium paratuberculosis, Salmonella enterica spp., and Mycoplasma spp . in raw milk was evaluated . Replicate experiments were run for 3 isolates of M . paratuberculosis, 3 serovars of Salmonella (derby, dublin, typhimurium); and 4 species of Mycoplasma (bovis, californicum, canadense, serogroup 7) at 2 different levels of experimental inoculation . In addition, HTST pasteurization experiments were performed on colostrum experimentally inoculated with M . paratuberculosis . After culture of the pasteurized milk samples, no viable M . paratuberculosis, Salmonella, or Mycoplasma were recovered, regardless of species, strain, or isolate . Pasteurization of colostrum was also effective in the destruction of M . paratuberculosis but resulted in an average 25% reduction in colostral immunoglobulin . These results suggest that HTST pasteurization is effective in generating a safer product to feed to young calves.

Vestn Ross Akad Med Nauk, 2004, (6), 13 - 5
{The possibility of using the attenuated recombinant strain of Salmonella enteritidis producing the HBc-antigen as a rectal vaccine in an experiment}; Donin MV et al.; Designing of a therapeutic vaccine for patients with chronic hepatitis B is a task of contemporary medicine . The natural way of administering the vaccine is the most attractive and inexpensive immunization variant . The use of attenuated strain Salmonella as a carrier of the virus antigen fits the purpose . With this idea in mind, the potentialities of the recombinant attenuated strain Salmonella Enteritidis E-23/pKHBc to replicate in the intestine, mesenteric nods and spleen of mice and to stimulate the immune response to HBc-antigen after its rectal administration (as suppositories) in mice were investigated . It was shown that the recombinant strain is discharged from the intestine within 6 hours after immunization, whereas, it is discharged on day 2 after immunization from the lymphatic nods and is traced there during the 5 subsequent days . Besides, the recombinant strain also possessed the possibility to persist in the spleen of mice for 42 days and to induce there the formation of antibodies to HBc-antigen.

Environ Res, 2004 Oct, 96(2), 109 - 18
Genotoxicity of PM10 and extracted organics collected in an industrial, urban and rural area in Flanders, Belgium; Brits E et al.; The variation in the genotoxic potency of PM10 in vitro in relation to the particle source type was investigated . Particles were collected at one urban, one rural, and one industrial site in Flanders . Genotoxicity was assessed using four different in vitro test systems exposed to PM10 in suspension and to the organic extracts of PM10 . Two of these systems were bacterial assays: the Salmonella mutagenicity test and the Vitotox test . In addition, the Comet assay and Micronucleus test were performed using human blood cells . Results show that exposure to PM10 and the organic extracts from both urban and industrial areas causes significant genetic damage . The Salmonella mutagenicity test was most suitable for the screening of PM10 and the organic extracts; the Micronucleus test was most suitable only for the screening of organic extracts, and original particles were toxic for the exposed lymphocytes . Clear dose-response curves were not established in the Comet and Vitotox assay, and organic extracts were apparently toxic in the latter . The total polycyclic aromatic hydrocarbon content of the organic extracts, as measured with GC/MS, ranged between 1 and 6 ng/m3 . Results obtained in this study suggest that PM10 causes DNA damage and mutations . The use of biological tests for the screening of air samples is useful to complement air quality control by chemical measurements.

Dev Comp Immunol, 2005, 29(1), 1 - 7
Cloning of porcine triggering receptor expressed on myeloid cells-1 (TREM-1) and its induction by lipopolysaccharide, peptidoglycan, and Salmonella enterica serovar Typhimurium infection; Ramanathan B et al.; Triggering receptors expressed on myeloid cells (TREM) are a family of activating receptors expressed on neutrophils and monocytes . These receptors are involved in regulation of immunity by inducing the expression of inflammatory cytokines and adhesion molecules, augmenting dendritic cell maturation, and are implicated in septic shock . Here we report the cloning of full-length TREM cDNA from porcine bone marrow cells, which predicts a 238 amino-acid peptide . Treating porcine bone marrow cells with lipopolysaccharide or peptidoglycan caused an increase in TREM-1 expression . Moreover, bone marrow cells derived from pigs that were orally challenged with Salmonella enterica serovar Typhimurium showed increases in TREM-1 at 8 and 24 h post-infection, respectively . Complete down-regulation of TREM-1 expression was observed at 48 h post-infection . These findings provide fundamental comparative data indicating that bacterial infection induces TREM-1 expression .

Int J Antimicrob Agents, 2004 Sep, 24(3), 300 - 3
Mutations in the gyrA gene in Salmonella enterica clinical isolates with decreased ciprofloxacin susceptibility; Escribano I et al.; The incidence of resistance to nalidixic acid has increased in the University General Hospital of Elche, Spain, and this paper describes the investigation of this phenomenon . This increase was mainly due to an increase of nalidixic-resistant Salmonella enterica serotype Enteritidis . Resistance to nalidixic acid is an indicator of decreased ciprofloxacin susceptibility (sensitivity 100%, specificity 96.7%) . Strains that were resistant to nalidixic acid and exhibited decreased susceptibility to ciprofloxacin had a single mutation in QRDR of gyrA: Asp87-Asn, Asp87-Tyr or Ser83-Phe . The sensitivity of S . enterica strains to nalidixic acid should be tested and the breakpoint of ciprofloxacin established by MENSURA applied, instead of that of the NCCLS for these strains.

Int J Antimicrob Agents, 2004 Sep, 24(3), 297 - 9
Scattergram analysis to explore the emerging problem related to in vitro susceptibility test for Salmonella enterica serovar Typhi to ciprofloxacin; Pal NK et al.; Ciprofloxacin susceptibility using a disk diffusion method and minimum inhibitory concentration (MIC) value determination for 421 S . Typhi isolates showed comparable results for 296 (70%) isolates with an MIC </=0.075 mg/L . However, of the remaining 125 strains that had MIC >/=0.1 mg/L, signifying resistance, 123 (98.4%) showed discrepant results with the disk diffusion test (66 sensitive, 57 intermediately sensitive) . This raises questions about National Committee for Clinical Laboratory Standards guidelines regarding the interpretative zone size for ciprofloxacin.

Mutat Res, 2004 Sep 12, 563(1), 25 - 34
In vitro mutagenicity and metabolism of the cycloaliphatic epoxy Cyracure UVR 6105; Kostoryz EL et al.; Cyracure UVR 6105 is a cycloaliphatic epoxy monomer and has both carboxylate and epoxy groups, with the potential for rapid polymerization . It is widely used in industry for the preparation of inks, resins, coatings, and was proposed for incorporation into dental composites . The objective of this study was to determine the mutagenic potential of this chemical related to its metabolite products . Several doses of Cyracure UVR 6105 were dissolved in DMSO and subjected to the Ames Salmonella mutagenicity assay . A metabolic activation system (S9-mix) was used consisting of Arochlor-induced liver S9 homogenate enriched with NADP and glucose-6-phosphate cofactors . In contrast to studies without S9-mix, Cyracure UVR 6105 exhibited enhanced genotoxic activities with strains TA100 and TA1535 in the presence of liver S9-mix . From in vitro metabolism of Cyracure UVR 6105 with S9-mix, as used in the Ames assay, several metabolites were identified . The alcohol metabolite, 3,4-epoxycyclohexylmethanol, containing intact epoxy group was identified in the organic solvent extract . This metabolite was synthesized and proved to be mutagenic against TA100 when assayed in the presence and absence of S9-mix . Results showed that the increased mutagenicity of Cyracure UVR-6105 in the presence of liver enzymes is due to the formation of the mutagenic metabolite 3,4-epoxycyclohexylmethanol.

Emerg Infect Dis, 2004 Jul, 10(7), 1307 - 10
Emergence of multidrug-resistant Salmonella Paratyphi B dT+, Canada; Mulvey MR et al.; We document an increase in the number of multidrug-resistant Salmonella enterica serovar Paratyphi B dT+ identified in Canada . Most of these strains harbor Salmonella genomic island 1 (SGI1) . Further studies are needed to determine factors contributing to the observed emergence of this multidrug-resistant strain.

BMC Microbiol . 2004 Aug 23;4(1):33.
Flagellin acting via TLR5 is the major activator of key signaling pathways leading to NF-kappa B and proinflammatory gene program activation in intestinal epithelial cells; Tallant T et al.; BACKGROUND: Infection of intestinal epithelial cells by pathogenic Salmonella leads to activation of signaling cascades that ultimately initiate the proinflammatory gene program . The transcription factor NF-kappa B is a key regulator/activator of this gene program and is potently activated . We explored the mechanism by which Salmonella activates NF-kappa B during infection of cultured intestinal epithelial cells and found that flagellin produced by the bacteria and contained on them leads to NF-kappa B activation in all the cells; invasion of cells by the bacteria is not required to activate NF-kappa B . RESULTS: Purified flagellin activated the mitogen activated protein kinase (MAPK), stress-activated protein kinase (SAPK) and I kappa B kinase (IKK) signaling pathways that lead to expression of the proinflammatory gene program in a temporal fashion nearly identical to that of infection of intestinal epithelial cells by Salmonella . Flagellin expression was required for Salmonella invasion of host cells and it activated NF-kappa B via toll-like receptor 5 (TLR5) . Surprisingly, a number of cell lines found to be unresponsive to flagellin express TLR5 and expression of exogenous TLR5 in these cells induces NF-kappa B activity in response to flagellin challenge although not robustly . Conversely, overexpression of dominant-negative TLR5 alleles only partially blocks NF-kappa B activation by flagellin . These observations are consistent with the possibility of either a very stable TLR5 signaling complex, the existence of a low abundance flagellin co-receptor or required adapter, or both . CONCLUSION: These collective results provide the evidence that flagellin acts as the main determinant of Salmonella mediated NF-kappa B and proinflammatory signaling and gene activation by this flagellated pathogen . In addition, expression of the fli C gene appears to play an important role in the proper functioning of the TTSS since mutants that fail to express fli C are defective in expressing a subset of Sip proteins and fail to invade host cells . Flagellin added in trans cannot restore the ability of the fli C mutant bacteria to invade intestinal epithelial cells . Lastly, TLR5 expression in weak and non-responding cells indicates that additional factors may be required for efficient signal propagation in response to flagellin recognition.

Naunyn Schmiedebergs Arch Pharmacol, 2004 Aug, 370(2), 140 - 5 Epub 2004 Jul 30.
Cloricromene in endotoxemia: role of NF-kappaB; Ianaro A et al.; In this study we investigated, for the first time in vivo, the effect of cloricromene, a cumarine derivative, on NF-kappaB activation in endotoxin-treated rats . Endotoxemia was induced in male rats by the intravenous injection of Salmonella typhosa lipopolysaccharide (LPS; 2 mg/kg/i.v.) . In vivo treatment with cloricromene (2 mg/kg/i.v.) 30 min before lipopolysaccharide administration reversed the LPS-induced loss in tone of the aortic rings, improved their reactivity to phenylephrine, decreased both nitric oxide (NO) and TNF-alpha serum levels by inhibiting LPS-induced inducible NO synthase and TNF-alpha mRNA expression, and interestingly inhibited LPS-induced NF-kappaB activation . Our data suggest that cloricromene protects rats from LPS by blocking LPS-induced NF-kappaB activation, leading to inhibition of NO and TNF-alpha overproduction and thereby reversing the LPS-induced vascular hyporeactivity.

Infect Immun, 2004 Sep, 72(9), 5522 - 5
The Salmonella enterica serovar typhimurium divalent cation transport systems MntH and SitABCD are essential for virulence in an Nramp1G169 murine typhoid model; Zaharik ML et al.; Nramp1 is a transporter that pumps divalent cations from the vacuoles of phagocytic cells and is associated with the innate resistance of mice to diverse intracellular pathogens . We demonstrate that sitA and mntH, genes encoding high-affinity metal ion uptake systems in Salmonella enterica serovar Typhimurium, are upregulated when Salmonella is internalized by Nramp1-expressing macrophages and play an essential role in systemic infection of congenic Nramp1-expressing mice.

Infect Immun, 2004 Sep, 72(9), 5498 - 501
Host response to a dam mutant of Salmonella enterica serovar enteritidis with a temperature-sensitive phenotype; Giacomodonato MN et al.; The temperature-sensitive dam mutant strain of Salmonella enterica serovar Enteritidis SD1 is highly attenuated and induces innate and protective immunity in mice . SD1 activates NF-kappaB and induces gamma interferon secretion . Early interaction of the SD1 mutant with intestinal epithelial cells was associated with ruffling of enterocytes . Invading bacteria were found inside Peyer's patches after inoculation.

Infect Immun, 2004 Sep, 72(9), 5097 - 105
Major histocompatibility complex class I peptide presentation after Salmonella enterica serovar typhimurium infection assessed via stable isotope tagging of the B27-presented peptide repertoire; Ringrose JH et al.; Reactive arthritis (ReA) induced by infection with several gram-negative bacteria is strongly associated with expression of the major histocompatibility complex class I molecule HLA-B27 . It is thought that due to the intracellular lifestyle of ReA-inducing bacteria, bacterial fragments can be presented by HLA-B27 . Cytotoxic T cells recognizing such bacterial peptides or other induced host peptides could cross-react with self peptides presented in the joints, giving rise to disease . Studies to analyze the B27 peptide repertoire in relation to infection were severely hampered, as complex peptide profiles obtained from separate infected and noninfected cell preparations had to be compared . For this study, we applied a new approach to examine the effect of Salmonella enterica serovar Typhimurium infection on the B27 peptide repertoire presented by the HLA-B*2704 subtype associated with disease . Firstly, we showed that both host cell and S . enterica serovar Typhimurium proteins can be tagged metabolically with stable-isotope-labeled arginine . We then designed experiments so that either the tagged endogenous or tagged bacterial B*2704-presented peptide repertoires from infected cells could be analyzed by mass spectrometry from single peptide preparations that included uninfected controls . Using this new approach, we found no evidence for significant changes in endogenous B*2704 peptide presentation after infection or for any S . enterica serovar Typhimurium-derived B27-bound peptide . In conclusion, the hypothesis that S . enterica serovar Typhimurium induces changes in B27 peptide presentation could not be supported.

Infect Immun, 2004 Sep, 72(9), 5052 - 62
Cooperative interactions between flagellin and SopE2 in the epithelial interleukin-8 response to Salmonella enterica serovar typhimurium infection; Huang FC et al.; Flagellin is an important stimulus for epithelial interleukin-8 (IL-8) secretion because of its ability to activate Toll-like receptor 5 (TLR5) . SopE2, a Salmonella guanine nucleotide exchange factor (GEF), is also involved in intestinal inflammation . To clarify the proinflammatory mechanisms of these proteins, we examined their effects on IL-8 secretion and intracellular signaling in T84 epithelial cells . A Salmonella strain lacking SopE2 (and its homolog SopE) induced lower levels of IL-8 than the wild type and exhibited reduced activation of mitogen-activated protein kinases (MAPKs) . Overexpression of wild-type SopE2 in this strain restored MAPK activation and augmented IL-8 production, whereas a mutant lacking GEF activity failed to increase IL-8 expression . Additional effects on signaling were demonstrated in transient transfection experiments, in which SopE2 enhanced the ability of TRAF6, a signal transducer downstream of TLR5, to activate the NF-kappaB transcription factor in 293 cells . Flagellin was also found to be required for IL-8 induction in T84 cells . In its absence, the ability of SopE2 overexpression to increase IL-8 secretion was impaired . Part of this impairment was related to the decreased motility of the flagellin-deficient strain, but lack of flagellin also affected translocation of SopE2 into the infected cells . Our results indicate that flagellin and SopE2 interact functionally at multiple levels to increase IL-8 secretion by epithelial cells-flagellin facilitating the translocation of SopE2, and SopE2 enhancing signaling pathways activated by flagellin . These observations offer a mechanistic explanation for the involvement of these proteins in the pathogenesis of Salmonella-induced gastroenteritis.

Water Sci Technol, 2004, 50(1), 301 - 8
Assessment of microbial infection risks posed by ingestion of water during domestic water use and full-contact recreation in a mid-southern African region; Steyn M et al.; A customised Water-related Quantitative Microbial Risk Assessment (WRQMRA) process was used to determine risk of infection to water ingested by users in the south-eastern Free State, South Africa . The WRQMRA consisted of an observed-adverse-effect-level approach (OAELA) and a quantitative microbial risk assessment (QMRA) . The OAELA was based on the occurrence of E . coli in the study waters to determine the possible risk of infection and the QMRA probable risk of infection by salmonellae . The WRQMRA was applied to recreational surface resource waters as well as waters from an unprotected spring and waters from the treated municipal supply that were stored in containers for domestic purposes . E . coli numbers were measured against expected infection levels expressed in water quality guidelines, while Salmonella counts were calculated to give the probable infection risk (Pi) . Ingestion was based on intake volumes compiled for the various water uses . E . coli occurred in numbers <10(6) in the surface waters, while the untreated spring and treated supply water contained E . coli of <10(2) and <10(1) respectively . Salmonella occurred in numbers of <10(3) in recreational waters, and <10(-1) in water used for domestic purposes . A single exposure to the mean (as well as 95th percentile) risk was calculated using a beta-Poisson dose-response model at ingestion volumes of 100 mL (for full-contact recreation) and 1,318 mL (for domestic water use) . Both the OAELA and the QMRA approaches indicated a risk of infection to recreational and domestic water users, even for a single exposure event, with the OAELA either over- or under-estimating the risk of infection for singular exposure events . This indicated that this method, used on its own, could not reliably predict a realistic risk of infection . It is recommended that the full WRQMRA process be used, and further developed to address several uncertainties that became evident during this study.

Euro Surveill . 2004 Jul 1;9(7) {Epub ahead of print}
A large increase of Salmonella infections in 2003 in the Netherlands: hot summer or side effect of the avian influenza outbreak?
Van Pelt W, Mevius DJ, Stoelhorst H, Kovats S, Van De Giessen AW, Wannet W, Duynhoven Y.
In June 2003, the Dutch national Salmonella centre reported a significant excess isolation rate of Salmonella Enteritidis when compared with earlier years in most regional public health laboratories . By the end of 2003, this amounted to an extra 540 laboratory confirmed cases for the whole of the Netherlands, which implies an estimated 7500 extra cases of gastroenteritis caused by S . Enteritidis in the general population, an increase of 50% on previous years . The hot summer could not explain the findings . Strong evidence has been found to suggest that the increase in importation of salmonella contaminated eggs, as a side effect of a concurrent avian influenza outbreak, was the most probable reason for this excess.

J Bacteriol, 2004 Sep, 186(17), 5883 - 98
Characterization of Salmonella enterica subspecies I genovars by use of microarrays; Porwollik S et al.; Subspecies 1 of Salmonella enterica is responsible for almost all Salmonella infections of warm-blooded animals . Within subspecies 1 there are over 2,300 known serovars that differ in their prevalence and the diseases that they cause in different hosts . Only a few of these serovars are responsible for most Salmonella infections in humans and domestic animals . The gene contents of 79 strains from the most prevalent serovars were profiled by microarray analysis . Strains within the same serovar often differed by the presence and absence of hundreds of genes . Gene contents sometimes differed more within a serovar than between serovars . Groups of strains that share a distinct profile of gene content can be referred to as "genovars" to distinguish them from serovars . Several misassignments within the Salmonella reference B collection were detected by genovar typing and were subsequently confirmed serologically . Just as serology has proved useful for understanding the host range and pathogenic manifestations of Salmonella, genovars are likely to further define previously unrecognized specific features of Salmonella infections.

J Bacteriol, 2004 Sep, 186(17), 5708 - 14
The eutT gene of Salmonella enterica Encodes an oxygen-labile, metal-containing ATP:corrinoid adenosyltransferase enzyme; Buan NR et al.; The eutT gene of Salmonella enterica was cloned and overexpressed, and the function of its product was established in vivo and in vitro . The EutT protein has an oxygen-labile, metal-containing ATP:co(I)rrinoid adenosyltransferase activity associated with it . Functional redundancy between EutT and the housekeeping ATP:co(I)rrinoid adenosyltransferase CobA enzyme was demonstrated through phenotypic analyses of mutant strains . Lack of CobA and EutT blocked ethanolamine utilization . EutT was necessary and sufficient for growth of an S . enterica cobA eutT strain on ethanolamine as a carbon and energy or nitrogen source . A eutT+ gene provided in trans corrected the adenosylcobalamin-dependent transcription of a eut-lacZ operon fusion in a cobA strain . Cell extracts enriched for EutT protein contained strong, readily detectable ATP:co(I)rrinoid adenosyltransferase activity . The activity was only detected in extracts maintained under anoxic conditions, with complete loss of activity upon exposure to air or treatment with the Fe2+ ion chelator bathophenanthroline . While the involvement of another metal ion cannot be ruled out, the observed sensitivity to air and bathophenanthroline suggests involvement of Fe2+ . We propose that the EutT protein is a unique metal-containing ATP:co(I)rrinoid adenosyltransferase . It is unclear whether the metal ion plays a structural or catalytic role.

Vaccine, 2004 Sep 9, 22(27-28), 3797 - 808
Mucosal immunization with purified flagellin from Salmonella induces systemic and mucosal immune responses in C3H/HeJ mice; Strindelius L et al.; This study investigated the immune response elicited in C3H/HeJ mice after oral, parenteral and nasal immunization with purified flagellin from Salmonella enterica serovar Enteritidis alone or conjugated to starch microparticles as adjuvant or together with the uptake-enhancer recombinant cholera toxin B-subunit (rCTB) . Systemic (IgM-IgG, IgA, IgG2a, IgG2b, IgG1) and local (s-IgA) humoral immune responses in the mice were analyzed using enzyme-linked immunosorbent assays (ELISA) . Primed splenocytes were also stimulated in vitro with flagellin and the supernatants analyzed for cytokine production . Finally, immunized mice were challenged orally with live Salmonella . A high flagellin-specific IgM-IgG response was seen in all groups, especially in mice immunized nasally with flagellin plus rCTB or subcutaneously, but a strong systemic antibody response was also induced when free antigen was given orally . Intranasal or subcutaneous immunization of mice with flagellin plus rCTB or oral immunization with flagellin plus microparticles resulted in a significantly greater mucosal response (higher s-IgA titers in feces) than seen in the control group (P <0.05) . The mucosal IgA responses were significantly correlated with the serum IgA titers . The subclass profile in serum revealed a mixed Th1/Th2-type response, with a predominance of Th1-type, as indicated by the subclass ratio (IgG1/IgG2a + IgG2b) . The splenocytes stimulated in vitro produced interferon (IFN)-gamma, at levels, which increased with time . The group immunized with flagellin plus rCTB subcutaneously had a relatively higher IFN-gamma response than the other groups . Interleukin (IL)-2 was also produced, especially in mice immunized nasally or subcutaneously with flagellin conjugated to microparticles . However, neither IL-4 nor IL-5 was produced in any of the groups . After oral challenge with live serovar Enteritidis, the groups immunized orally or nasally with free flagellin had significantly lower degree of infection than the control group (P <0.05).

Vaccine, 2004 Sep 9, 22(27-28), 3744 - 50
Recombinant Salmonella enterica serovar Typhi in a prime-boost strategy; Vindurampulle CJ et al.; This study investigated the utility of attenuated Salmonella enterica serovar Typhi strain CVD 908-htrA (908 h) in a heterologous prime-boost strategy . Mice primed intranasally (i.n.) with 908 h expressing fragment C (Frag C) of tetanus toxin and boosted intramuscularly (i.m.) with tetanus toxoid (TT) mounted enhanced and accelerated serum IgG anti-Frag C responses in comparison to unprimed, vector-primed and homologously-primed and boosted mice . Serum antitoxin responses were also determined; mice that were vaccinated following a heterologous prime-boost regimen exhibited the highest levels of Frag C-specific toxin neutralizing antibodies 1 week after boosting . Mice primed and boosted i.m . with TT developed a significantly greater proportion of serum IgG1 antibodies and weaker IFN-gamma levels in contrast to those primed intranasally (i.n.) with rS . Typhi that were homologously or heterologously boosted . These encouraging pre-clinical data provide a rational basis for undertaking a pilot clinical trial to evaluate this strategy . An ability to stimulate enhanced, accelerated responses to parenteral vaccination following mucosal priming may be advantageous in the immunoprophylaxis of many infectious diseases, including those of biodefense importance.

J Agric Food Chem, 2004 Aug 25, 52(17), 5443 - 8
Preventive effect of sialylglycopeptide-nondigestive polysaccharide conjugates on salmonella infection; Sugita-Konishi Y et al.; We have previously reported that sialylglycopeptide (SGP) and its derivatives isolated from egg yolk had a preventive effect on Salmonella infection in vivo; however, their retention time in the gut was rather short . To improve on this, SGP was conjugated with carboxymethyl cellulose (CMC) or carboxymethyl dextran (CMD) . The conjugates inhibited the binding of Salmonella enteritidis and Escherichia coli to Caco-2 cells . Infection experiments with mice revealed that the SGP-CMD conjugate (SGP-CMD) had a strong protective effect against Salmonella infection . A turnover experiment in mice administered with radiolabeled SGP-CMD showed that SGP-CMD was more slowly absorbed into the blood and thus remained longer in the intestinal tract than SGP . SGP-CMD itself did not influence the production of tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta, or nitrite ion (NO(2)(-)) by macrophages, although it suppressed that of TNF-alpha and NO(2)(-) in zymosan-treated macrophages, suggesting no causative effects of inflammation in SGP-CMD . SGP-CMD is potentially useful as a food ingredient with a preventive effect on Salmonella infection.

Res Microbiol, 2004 Sep, 155(7), 568 - 70
Supplement 2002 (no . 46) to the Kauffmann-White scheme; Popoff MY et al.; This supplement reports the characterization of 18 new Salmonella serovars recognized in 2002 by the WHO Collaborating Centre for Reference and Research on Salmonella: 12 were assigned to S . enterica subspecies enterica, 2 to subspecies salamae, 2 to subspecies diarizonae, 1 to subspecies houtenae and 1 to S . bongori.

Res Microbiol, 2004 Sep, 155(7), 543 - 52
Identification of a new Salmonella enterica serovar Enteritidis locus involved in cell invasion and in the colonisation of chicks; Amy M et al.; Poultry products contaminated with Salmonella enterica serovar Enteritidis are a major cause of foodborne disease in industrialized countries . Knowledge of how poultry is colonised is essential for reducing contamination of these products . We have characterized the bacterial yfg-eng locus involved in chicken colonisation . Its sequencing revealed four open reading frames (ORF), yfgM, yfgL, engA and yfgJ, all transcribed in the same orientation . An yfgL mutant of S . Enteritidis colonised the caeca (P < 0.05) and the spleens (P < 0.01) of one-day-old chicks subnormally 2 and 5 days after oral inoculation . This lower virulence was correlated with reduced secretion of the SPI-1 and flagellar proteins in the yfgL mutant compared to the wild-type strain . Consistent with this, the S . Enteritidis yfgL mutant was less motile than the wild type and fewer invaded enterocytes (P < 0.05) and avian HD11 macrophages (P < 0.001) . All these defects could be partially overcome by inserting the yfg-eng locus into the mutant on a recombinant plasmid.

Microb Pathog, 2004 Aug, 37(2), 65 - 72
Characterization of Salmonella pathogenicity island 1 type III secretion-dependent hemolytic activity in Salmonella enterica serovar Typhimurium; Miki T et al.; A number of bacteria that are pathogenic for animals and plants possess a type III secretion system (TTSS) to translocate virulence-associated proteins into host cells . In several bacteria, it has been reported that the TTSS is correlated with an ability to cause contact-dependent hemolysis in vitro . Here, we showed that the Salmonella enterica serovar Typhimurium strain SL1344 exhibited Salmonella pathogenicity island 1 type III secretion-dependent, contact-mediated, hemolytic activity . Mutations with a single deletion in genes encoding putative pore-forming proteins, SipB and SipC, secreted by the TTSS abolished hemolytic activity . In addition, the osmoprotection studies revealed that molecules larger than PEG2000 conferred significant protection against lysis induced by Salmonella . These results indicate that the hemolysis generated by Salmonella is due to the formation of pores within the erythrocyte membrane .

Immunology, 2004 Sep, 113(1), 139 - 48
Differential cytokine mRNA expression in heterophils isolated from Salmonella-resistant and -susceptible chickens; Swaggerty CL et al.; We recently showed that increased in vitro heterophil functional efficiency translates to increased in vivo resistance to a systemic Salmonella enteritidis (SE) infection utilizing a parental pair of broiler chickens (lines A and B) and the F1 reciprocal crosses (C and D) . Heterophils produce cytokines and modulate acute protection against Salmonella in young poultry . Therefore, we hypothesize that heterophils from SE-resistant chickens (A and D) have the ability to produce an up-regulated pro-inflammatory cytokine response compared to that of heterophils from SE-susceptible chickens (B and C) . In this study, heterophils were isolated from day-old chickens and treated with either RPMI-1640 (as the control), or phagocytic agonists (SE, or SE opsonized with either normal chicken serum or immune serum against SE) and cytokine mRNA expression assessed using real-time quantitative reverse transcription-polymerase chain reaction . Heterophils from SE-resistant chickens (A and D) had significantly higher levels of pro-inflammatory cytokine (interleukin (IL)-6, IL-8, and IL-18) mRNA expression upon treatment with all agonists compared to heterophils from SE-susceptible lines (B and C) . Further, heterophils from SE-resistant chickens had significantly decreased mRNA expression levels of transforming growth factor-beta4, an anti-inflammatory cytokine, when compared to heterophils from SE-susceptible chickens . These data indicate cytokine gene expression in heterophils may be a useful parameter in determining resistance to Salmonella, as indicated by our previous in vivo SE studies . Therefore, heterophil functional efficiency and cytokine production may be useful biomarkers for poultry breeders to consider when developing new immunocompetent lines of birds.

Microbes Infect, 2004 Aug, 6(10), 901 - 10
Protective efficacy of IgA monoclonal antibodies to O and H antigens in a mouse model of intranasal challenge with Salmonella enterica serotype Enteritidis; Iankov ID et al.; Protective properties of immunoglobulin A (IgA) monoclonal antibodies (MAbs) directed against O and H antigens of Salmonella enterica serotype Enteritidis (S . enteritidis) were evaluated in a model of generalized infection after intranasal (i.n.) inoculation of BALB/c mice . Passive i.n . instillation of antibodies 1 h before i.n . challenge did not prevent infection, and mice developed rapid inflammatory response in the lower respiratory tract . The passive systemic immunization was partially protective and a single intravenous (i.v.) injection of both O and H antigen specific IgA antibodies prolonged survival period of the infected animals . Permanent secretion of O:9 specific IgA MAb 177E6 into the respiratory tract in a "backpack" tumor model protected 50% of animals infected i.n . with a high dose of virulent S . enteritidis strain . Thus, secretory IgA (S-IgA) directed against O:9 antigen alone can prevent bacterial invasion in the respiratory epithelium.

Epidemiol Infect, 2004 Aug, 132(4), 619 - 26
Surveillance of childhood diarrhoeal disease in Hong Kong, using standardized hospital discharge data; Nelson EA et al.; Discharge information for all Hong Kong government hospitals, which is routinely collected through the Clinical Management System (CMS), was used to assess the relative importance of all causes of diarrhoeal illness and to address the issue of under-diagnosis of rotavirus by linking discharge diagnostic codes with actual laboratory results for one hospital . Of all children less than 5 years of age hospitalized in Hong Kong in the 2-year period July 1997 to June 1999, 12,257 (11%) were discharged with a primary diarrhoea diagnosis (74% coded as non-specified, 10.4% as rotavirus, 11% as Salmonella and 5% as other viral or bacterial) . Linked laboratory and discharge data for one hospital demonstrated that 15% (n = 1522) of all admissions had a primary diarrhoea diagnosis and that 40% of these had a specimen sent for rotavirus testing, of which 37% were positive . However, 46% (67/145) of children with a diagnosis of rotavirus infection had no virology result, and 69% (172/248) of positive rotavirus results were in children with no diagnosis indicating rotavirus infection . Modification of the CMS to routinely combine existing computerized laboratory data with the CMS discharge diagnoses and to develop mechanisms to enhance reliability of discharge diagnosis coding could produce a powerful resource for disease surveillance, auditing and for monitoring the impact of future vaccination and other prevention programmes.

Epidemiol Infect, 2004 Aug, 132(4), 571 - 7
An outbreak due to peanuts in their shell caused by Salmonella enterica serotypes Stanley and Newport--sharing molecular information to solve international outbreaks; Kirk MD et al.; Salmonellosis is a global problem caused by the international movement of foods and high incidence in exporting countries . In September 2001, in an outbreak investigation Australia isolated Salmonella Stanley from imported peanuts, which resulted in a wider investigation in Canada, England & Wales and Scotland . Patients infected with Salmonella serotypes known to be isolated from peanuts and reported to surveillance systems were interviewed to determine exposure histories . Tagged image file format (TIFF) images of pulsed-field gel electrophoresis (PFGE) patterns of Salmonella isolates were shared electronically amongst laboratories . Laboratories tested packets of 'Brand X' peanuts from various lots and product lines . In total, 97 cases of S . Stanley and 12 cases of S . Newport infection were found . Seventy-three per cent (71/97) of S . Stanley cases were in persons of Asian ethnicity . Twenty-eight per cent of cases recalled eating Brand X peanuts and a further 13% had peanuts in their house in the previous month or had eaten Asian-style peanuts . Laboratories isolated S . Stanley, S . Newport, S . Kottbus, S . Lexington and S . Unnamed from Brand X peanuts . Isolates of S . Stanley from peanuts and human patients were indistinguishable by PFGE . This international outbreak resulted from a product originating from one country affecting several others . Rapid sharing of electronic DNA images was a crucial factor in delineating the outbreak; multinational investigations would benefit from a harmonized approach.

Wiad Lek, 2004, 57(3-4), 131 - 4
{Infections of Salmonella in children aged 0-36 months--clinical and epidemiological aspects}; Staszewska-Kwak A et al.; In this work we presented a retrospective analysis of Salmonella infections in 163 children aged between 0-36 months . The children were treated in IV Department of Pediatrics at Medical University of Silesia (Poland) in years 1987-1998 . We analyzed: clinical course, dependence between age of the patients and the type of Salmonella, number of infections and their seasonal incidence during 12 years of observation . These relations were compared with the group of 17 children with Salmonella infections treated in the Department of Pediatrics GCZDzM in Katowice in 2001.

Srp Arh Celok Lek, 2004 Mar-Apr, 132(3-4), 104 - 7
{Reiter's syndrome after Salmonella infection}; Inhibition of cell surface MHC class II expression by Salmonella; Immunology Division, Department of Pathology, University of Cambridge, Cambridge, GBPeptide presentation by MHC molecules is an essential component of the adaptive immune response . To persist in a host, many pathogens have evolved strategies that interfere with MHC antigen-presentation . We show that in human cells harboring intracellular Salmonella, MHC class II cell surface expression was substantially reduced . The effect was specific for MHC class II as expression of additional surface receptors remained unchanged . We investigated the underlying mechanism and showed that class II biosynthesis and peptide loading were unaffected by the presence of Salmonella; however, infection led to an intracellular accumulation of mature molecules . The intracellular class II colocalized with lysosome-associated membrane protein-1 and HLA-DM but not with the Salmonella-containing vacuole . Using Salmonella mutants defective in different components and effectors of the Salmonella pathogenicity island-2 type-III secretion system, we traced the effect on class II to the sifA locus . SifA has been shown to be involved in recruiting membrane for the Salmonella-containing vacuoles . Our data suggest an additional role for SifA in interfering with MHC class II antigen-presentation .

Clin Infect Dis, 2004 Jul 15, 39(2), 186 - 91 Epub 2004 Jul 01.
Typhoid fever in travelers: who should be targeted for prevention?
Steinberg EB, Bishop R, Haber P, Dempsey AF, Hoekstra RM, Nelson JM, Ackers M, Calugar A, Mintz ED.
To clarify indications for typhoid vaccination, we reviewed laboratory-confirmed cases of typhoid fever reported to the United States Centers for Disease Control and Prevention between 1994 and 1999 . To estimate the risk of adverse events associated with typhoid vaccination, we reviewed reports to the Vaccine Adverse Event Reporting System for the same period . Acute Salmonella enterica serotype Typhi infection was reported for 1393 patients . Of these patients, recent travel was reported by 1027 (74%), only 36 (4%) of whom reported having received a vaccination . Six countries accounted for 76% of travel-associated cases (India {30%}, Pakistan {13%}, Mexico {12%}, Bangladesh {8%}, The Philippines {8%}, and Haiti {5%}) . For 626 travelers who traveled to a single country, the length of stay was <or=1 week for 31 (5%), <or=2 weeks for 100 (16%), <or=3 weeks for 169 (27%), <or=4 weeks for 232 (37%), <or=5 weeks for 338 (54%), and <or=6 weeks for 376 (60%) . Reports of serious adverse events due to typhoid vaccination were very rare . Vaccination should be considered even for persons planning short-term travel to high-risk areas.

Mol Microbiol, 2004 Aug, 53(4), 1123 - 34
GGDEF and EAL domains inversely regulate cyclic di-GMP levels and transition from sessility to motility; Simm R et al.; Cyclic nucleotides represent second messenger molecules in all kingdoms of life . In bacteria, mass sequencing of genomes detected the highly abundant protein domains GGDEF and EAL . We show here that the GGDEF and EAL domains are involved in the turnover of cyclic-di-GMP (c-di-GMP) in vivo whereby the GGDEF domain stimulates c-di-GMP production and the EAL domain c-di-GMP degradation . Thus, most probably, GGDEF domains function as c-di-GMP cyclase and EAL domains as phosphdiesterase . We further show that, in the pathogenic organism Salmonella enterica serovar Typhimurium, the nosocomial pathogen Pseudomonas aeruginosa and the commensal species Escherichia coli, GGDEF and EAL domains mediate similar phenotypic changes related to the transition between sessility and motility . Thus, the data suggest that c-di-GMP is a novel global second messenger in bacteria the metabolism of which is controlled by GGDEF and EAL domain proteins.

Behav Brain Res, 2004 Sep 23, 154(1), 63 - 9
Endotoxin exposure in early life alters the development of anxiety-like behaviour in the Fischer 344 rat; Walker FR et al.; Previous research in the rat has demonstrated that neonatal exposure to bacterial endotoxin alters the level of anxiety-like behaviour displayed in adulthood . Currently, however, little is known about the emergence and development of this type of behaviour . Given the ability of neonatal endotoxin exposure to alter neural substrates involved in regulating anxiety, we tested the hypothesis that it may also alter the developmental trajectory of anxiety-like behaviour in the rat . Male Fischer 344 neonatal rats were treated with endotoxin (0.05 mg/kg lipopolysaccharide from Salmonella enteriditis) or vehicle on postnatal days 3 and 5 . Age related changes in anxiety-like behaviour were subsequently investigated using the elevated plus maze apparatus at three developmental time points; adolescence (43 days), adulthood (80 days) and senescence (400 days) . Neonatal endotoxin exposure was found to significantly increase circulating levels of corticosterone on postnatal days 3 and 5 at 4 h postadministration (P < 0.05) . Additionally, endotoxin exposure was found to markedly alter anxiety-like behaviour in adulthood and senescence (P < 0.05) . Specifically, adult and senescent endotoxin treated animals displayed significantly more anxiety-like behaviour than vehicle treated controls . Interestingly no significant differences in anxiety-like behaviour were observed between treatment groups during adolescence . These findings highlight the importance of the early life microbial environment in the development of emotional behaviour and suggests that neonatal infection may be an important predictor of susceptibility to anxiety related disorders in adult life.

Indian J Med Res, 2004 Jul, 120(1), 35 - 8
Presence of sopE gene & its phenotypic expression among different serovars of Salmonella isolated from man & animals; Rahman H et al.; BACKGROUND & OBJECTIVES: Salmonellae cause a spectrum of diseases in man and animals but their virulence factors responsible for induction of gastroenteritis and/or systematic infection are still poorly understood . Also, the different subspecies and serovars of Salmonella differ considerably in their virulence for man and animals . There is increasing evidence that Salmonella possesses a dedicated protein secretion system denoted type III secretion system (TTSS) that is involved in the early stage of Salmonella infection . One such TTSS is Salmonella outer protein E (SopE) that helps in the invasion of Salmonella by stimulating membrane ruffling . In the present study the presence of sopE gene and its phenotypic expression (SopE protein) among different serovars of Salmonella enterica isolated from man and animals in India was investigated . METHODS: A total of 50 isolates of S . enterica belonging to 11 serovars were tested for the presence of sopE gene by polymerase chain reaction . The in vitro phenotypic expression of SopE protein was detected by Western blotting using anti-SopE serum . RESULTS: Of the 50 isolates of S . enterica belonging to 11 serovars tested for the presence of sopE,14 belonging to three serovars viz., Enteritidis, Gallinarum and Virchow were found to carry the sopE gene . Similarly, 13 isolates belonging to same three serovars were found to express SopE protein phenotypically as detected by Western blotting using anti-SopE serum . INTERPRETATION & CONCLUSION: The results indicated that sopE gene appeared to be distributed and conserved among only a few serovars of Salmonella (Enteritidis, Gallinarum and Virchow) irrespective of their source of isolation . The presence of sopE gene in Salmonella provides an important pathogenic means to invade epithelial cells.

BMC Microbiol . 2004 Aug 06;4(1):31.
Towards the development of a DNA-sequence based approach to serotyping of Salmonella enterica; Mortimer CK et al.; BACKGROUND: The fliC and fljB genes in Salmonella code for the phase 1 (H1) and phase 2 (H2) flagellin respectively, the rfb cluster encodes the majority of enzymes for polysaccharide (O) antigen biosynthesis, together they determine the antigenic profile by which Salmonella are identified . Sequencing and characterisation of fliC was performed in the development of a molecular serotyping technique . RESULTS: FliC sequencing of 106 strains revealed two groups; the g-complex included those exhibiting "g" or "m,t" antigenic factors, and the non-g strains which formed a second more diverse group . Variation in fliC was characterised and sero-specific motifs identified . Furthermore, it was possible to identify differences in certain H antigens that are not detected by traditional serotyping . A rapid short sequencing assay was developed to target serotype-specific sequence motifs in fliC . The assay was evaluated for identification of H1 antigens with a panel of 55 strains . CONCLUSION: FliC sequences were obtained for more than 100 strains comprising 29 different H1 alleles . Unique pyrosequencing profiles corresponding to the H1 component of the serotype were generated reproducibly for the 23 alleles represented in the evaluation panel . Short read sequence assays can now be used to identify fliC alleles in approximately 97% of the 50 medically most important Salmonella in England and Wales . Capability for high throughput testing and automation give these assays considerable advantages over traditional methods.

J AOAC Int, 2004 Jul-Aug, 87(4), 867 - 83
Evaluation of VIDAS Salmonella (SLM) immunoassay method with Rappaport-Vassiliadis (RV) medium for detection of Salmonella in foods: collaborative study; McMahon WA et al.; A collaborative study was conducted to compare the VIDAS Salmonella (SLM) with Rappaport-Vassiliadis (RV) method for detection of Salmonella in foods to the current standard method presented in the U.S . Food and Drug Administration's Bacteriological Analytical Manual (BAM) and the culture method presented in AOAC's Official Methods of Analysis . The VIDAS SLM with RV method uses tetrathionate broth in combination with RV medium in place of selenite cystine broth for selective enrichment, thereby eliminating the hazardous waste issue for laboratories . Twenty five laboratories participated in the evaluation, each testing one or more of 8 test products: nonfat dry milk, dried egg, soy flour, lactic casein, milk chocolate, raw ground pork, raw ground turkey, and raw peeled shrimp . Results of the study showed no significant differences in the numbers of confirmed positive samples with the VIDAS SLM with RV procedure and the BAM/AOAC culture procedure . The VIDAS SLM with RV method was effective for rapid detection of Salmonella in foods . It is recommended that AOAC INTERNATIONAL modify the VIDAS Salmonella SLM procedure to include the RV method.

J AOAC Int, 2004 Jul-Aug, 87(4), 861 - 6
Multicenter validation of PCR-based method for detection of Salmonella in chicken and pig samples; Malorny B et al.; As part of a standardization project, an interlaboratory trial including 15 laboratories from 13 European countries was conducted to evaluate the performance of a noproprietary polymerase chain reaction (PCR)-based method for the detection of Salmonella on artificially contaminated chicken rinse and pig swab samples . The 3 levels were 1-10, 10-100, and 100-1000 colony-forming units (CFU)/100 mL . Sample preparations, including inoculation and pre-enrichment in buffered peptone water (BPW), were performed centrally in a German laboratory; the pre-PCR sample preparation (by a resin-based method) and PCR assay (gel electrophoresis detection) were performed by the receiving laboratories . Aliquots of BPW enrichment cultures were sent to the participants, who analyzed them using a thermal lysis procedure followed by a validated Salmonella-specific PCR assay . The results were reported as negative or positive . Outlier results caused, for example, by gross departures from the experimental protocol, were omitted from the analysis . For both the chicken rinse and the pig swab samples, the diagnostic sensitivity was 100%, with 100% accordance (repeatability) and concordance (reproducibility) . The diagnostic specificity was 80.1% (with 85.7% accordance and 67.5% concordance) for chicken rinse, and 91.7% (with 100% accordance and 83.3% concordance) for pig swab . Thus, the interlaboratory variation due to personnel, reagents, thermal cyclers, etc., did not affect the performance of the method, which will be proposed as part of a developing international PCR standard.

J Immunol, 2004 Aug 15, 173(4), 2607 - 14
Characterization of bovine homologues of granulysin and NK-lysin; Endsley JJ et al.; Granulysin and NK-lysin are antimicrobial proteins found in the granules of human and swine cytotoxic lymphocytes . A murine counterpart to granulysin has not been identified to date, indicating the importance of additional models to fully characterize the role of granulysin-like molecules in the immune response to infectious disease . Two partial nucleotide sequences corresponding to the complete functional domain of granulysin and NK-lysin were amplified from bovine PBMC mRNA . Following stimulation with phorbol ester and calcium ionophore, expression of the bovine gene was detected in CD3(+) T cells, CD4(+) T cells, CD8(+) T cells, WC1(+) gammadelta T cells, and PBMC depleted of CD3(+) T cells, but was absent in CD21(+) cells and CD14(+) cells . Intracellular flow cytometry and immunoblotting confirmed the presence of protein corresponding to the bovine granulysin homologue in activated T lymphocytes and PBMC . Synthetic human, bovine, and swine peptides corresponding to the C terminus of helix 2 through helix 3 region of granulysin displayed potent antimicrobial activity against Escherichia coli, Salmonella enteritidis, Staphylococcus aureus, and Mycobacterium bovis bacillus Calmette-Guerin . Human and bovine peptides corresponding to helix 2 displayed antimycobacterial activity against M . bovis bacillus Calmette-Guerin . Expression of the bovine gene was detected in laser microscopy-dissected lymph node lesions from an M . bovis-infected animal . The identification of a biologically active bovine homologue to granulysin demonstrates the potential of the bovine model in characterizing the role of granulysin in the immune response to a variety of infectious agents.

Appl Environ Microbiol, 2004 Aug, 70(8), 4840 - 7
Protein folding failure sets high-temperature limit on growth of phage P22 in Salmonella enterica serovar Typhimurium; Pope WH et al.; The high-temperature limit for growth of microorganisms differs greatly depending on their species and habitat . The importance of an organism's ability to manage thermal stress is reflected in the ubiquitous distribution of the heat shock chaperones . Although many chaperones function to reduce protein folding defects, it has been difficult to identify the specific protein folding pathways that set the high-temperature limit of growth for a given microorganism . We have investigated this for a simple system, phage P22 infection of Salmonella enterica serovar Typhimurium . Production of infectious particles exhibited a broad maximum of 150 phage per cell when host cells were grown at between 30 and 39 degrees C in minimal medium . Production of infectious phage declined sharply in the range of 40 to 41 degrees C, and at 42 degrees C, production had fallen to less than 1% of the maximum rate . The host cells maintained optimal division rates at these temperatures . The decrease in phage infectivity was steeper than the loss of physical particles, suggesting that noninfectious particles were formed at higher temperatures . Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a decrease in the tailspike adhesins assembled on phage particles purified from cultures incubated at higher temperatures . The infectivity of these particles was restored by in vitro incubation with soluble tailspike trimers . Examination of tailspike folding and assembly in lysates of phage-infected cells confirmed that the fraction of polypeptide chains able to reach the native state in vivo decreased with increasing temperature, indicating a thermal folding defect rather than a particle assembly defect . Thus, we believe that the folding pathway of the tailspike adhesin sets the high-temperature limit for P22 formation in Salmonella serovar Typhimurium.

Appl Environ Microbiol, 2004 Aug, 70(8), 4613 - 20
Treatment of Salmonella enterica serovar Enteritidis with a sublethal concentration of trisodium phosphate or alkaline pH induces thermotolerance; Sampathkumar B et al.; The responses of Salmonella enterica serovar Enteritidis to a sublethal dose of trisodium phosphate (TSP) and its equivalent alkaline pH made with NaOH were examined . Pretreatment of S . enterica serovar Enteritidis cells with 1.5% TSP or pH 10.0 solutions resulted in a significant increase in thermotolerance, resistance to 2.5% TSP, resistance to high pH, and sensitivity to acid and H(2)O(2) . Protein inhibition studies with chloramphenicol revealed that thermotolerance, unlike resistance to high pH, was dependent on de novo protein synthesis . Two-dimensional polyacrylamide gel electrophoresis (PAGE) of total cellular proteins from untreated control cells resolved as many as 232 proteins, of which 22 and 15% were absent in TSP- or alkaline pH-pretreated cells, respectively . More than 50% of the proteins that were either up- or down-regulated by TSP pretreatment were also up- or down-regulated by alkaline pH pretreatment . Sodium dodecyl sulfate-PAGE analysis of detergent-insoluble outer membrane proteins revealed the up-regulation of at least four proteins . Mass spectrometric analysis showed the up-regulated proteins to include those involved in the transport of small hydrophilic molecules across the cytoplasmic membrane and those that act as chaperones and aid in the export of newly synthesized proteins by keeping them in open conformation . Other up-regulated proteins included common housekeeping proteins like those involved in amino acid biosynthesis, nucleotide metabolism, and aminoacyl-tRNA biosynthesis . In addition to the differential expression of proteins following TSP or alkaline pH treatment, changes in membrane fatty acid composition were also observed . Alkaline pH- or TSP-pretreated cells showed a higher saturated and cyclic to unsaturated fatty acid ratio than did the untreated control cells . These results suggest that the cytoplasmic membrane could play a significant role in the induction of thermotolerance and resistance to other stresses following TSP or alkaline pH treatment.

Mol Cell Probes, 2004 Oct, 18(5), 333 - 9
Rapid detection of Salmonella by polymerase chain reaction; Riyaz-Ul-Hassan S et al.; Salmonella enterotoxin gene (stn) was sequenced from Salmonella enterica serotypes: Typhimurium, Typhi, Paratyphi A and B . The sequences from all the four serotypes showed complete homology with the already reported stn gene sequence of the serotype Typhimurium . As a tool for detection of this organism, four pairs of oligonucleotide primers were designed to amplify different fragments of this important pathological marker . The protocols were standardized with serotype Typhimurium in such a way so as to complete the PCR reaction in 75-90 min . These primers were found to generate specific amplicons with all the serotypes of Salmonella tested . The PCR protocols were found to be highly specific as no amplifications, specific or non-specific, were found when reactions were run using non-Salmonella DNA as template . The employment of a nested PCR markedly increased the sensitivity of the assay system in natural water samples . The protocol described herein is highly sensitive as it detects less than 10 cells of Salmonella in 250 microl of blood and approx . 1 cell in 1 ml of water without any enrichment . For the validation of this protocol, 72 coded samples of 11% skimmed milk spiked with different pathogens were received from NICED, Kolkata and analyzed for the presence of Salmonella . Our procedures detected correctly the presence of Salmonella in nine samples . 50 samples of raw milk were subjected to this PCR after enrichment for 8 h and 6 samples were found positive for Salmonella . The study indicates that Salmonella enterotoxin (stn) gene is highly conserved and the protocol devised in this study can be used as rapid and reliable method for detection of Salmonella spp . in water, milk and blood samples.

Vestn Ross Akad Med Nauk, 2004, (7), 51 - 3
{Some approaches to elaborating vaccines against the HIV infection}; Boichenko MN et al.; A variety of approaches to creating vaccines against the HIV-infection are discussed in the paper . It is demonstrated that vaccines can be used both for treatment and prevention . They can be synthetic, DNA-vaccines and vector-type ones based on the attenuated recombinant strain of Salmonella . Apart from gp120, reverse transcriptase and tat-gene products can be used as the antigen.

Int J Med Microbiol, 2004 Jul, 294(1), 59 - 63
ST64B is a defective bacteriophage in Salmonella enterica serovar Typhimurium DT64 that encodes a functional immunity region capable of mediating phage-type conversion; Tucker CP et al.; The Salmonella enterica subsp . enterica serovar Typhimurium (S . Typhimurium) defective bacteriophage ST64B has a putative immunity (immC) region consisting of cI, cro and cII-like genes . Since ST64B is widespread in S . Typhimurium, studies were undertaken to determine whether this region might be functional and influence phage typing results . Cloning of ST64B immC-like genes and their subsequent expression in S . Typhimurium DTs showed that this region is able to mediate phage-type conversion in DTs 41 and 44 . This confirms the functionality of the immC region and the patterns of lysis produced by phage typing are consistent with the predicted mechanism of action of the encoded protein products.

J Biol Chem, 2004 Oct 15, 279(42), 44023 - 9 Epub 2004 Aug 03.
Molecular structure of alpha-D-glucose-1-phosphate cytidylyltransferase from Salmonella typhi; Koropatkin NM et al.; Dideoxysugars, which display biological activities ranging from mediating cell-cell interactions to serving as components in some antibiotics, are synthesized in various organisms via complex biochemical pathways that begin with the attachment of alpha-D-glucose 1-phosphate to either CTP or dTTP . Here we describe the three-dimensional structure of the alpha-D-glucose-1-phosphate cytidylyltransferase from Salmonella typhi, which catalyzes the first step in the production of CDP-tyvelose . For this investigation, the enzyme was crystallized in the presence of its product, CDP-glucose . In contrast to previous reports, the enzyme exists as a fully integrated hexamer with 32-point group symmetry . Each subunit displays a "bird-like" appearance with the "body" composed predominantly of a seven-stranded mixed beta-sheet and the two "wings" formed by beta-hairpin motifs . These two wings mediate subunit-subunit interactions along the 3-fold and 2-fold rotational axes, respectively . The six active sites of the hexamer are situated between the subunits related by the 2-fold rotational axes . CDP-glucose is anchored to the protein primarily by hydrogen bonds with backbone carbonyl oxygens and peptidic NH groups . The side chains of Arg111 and Asn188 from one subunit and Glu178 and Lys179 from the second subunit are also involved in hydrogen bonding with the ligand . The topology of the main core domain bears striking similarity to that observed for glucose-1-phosphate thymidylyltransferase and 4-diphosphocytidyl-2-C-methylerythritol synthetase.

J Bacteriol, 2004 Aug, 186(16), 5230 - 8
Differences in enzymatic properties allow SodCI but not SodCII to contribute to virulence in Salmonella enterica serovar Typhimurium strain 14028; Krishnakumar R et al.; Salmonella enterica serovar Typhimurium produces two Cu/Zn cofactored periplasmic superoxide dismutases, SodCI and SodCII . While mutations in sodCI attenuate virulence eightfold, loss of SodCII does not confer a virulence phenotype, nor does it enhance the defect observed in a sodCI background . Despite this in vivo phenotype, SodCI and SodCII are expressed at similar levels in vitro during the stationary phase of growth . By exchanging the open reading frames of sodCI and sodCII, we found that SodCI contributes to virulence when placed under the control of the sodCII promoter . In contrast, SodCII does not contribute to virulence even when expressed from the sodCI promoter . Thus, the disparity in virulence phenotypes is due primarily to some physical difference between the two enzymes . In an attempt to identify the unique property of SodCI, we have tested factors that might affect enzyme activity inside a phagosome . We found no significant difference between SodCI and SodCII in their resistance to acid, resistance to hydrogen peroxide, or ability to obtain copper in a copper-limiting environment . Both enzymes are synthesized as apoenzymes in the absence of copper and can be fully remetallated when copper is added . The one striking difference that we noted is that, whereas SodCII is released normally by an osmotic shock, SodCI is "tethered" within the periplasm by an apparently noncovalent interaction . We propose that this novel property of SodCI is crucial to its ability to contribute to virulence in serovar Typhimurium.

Naunyn Schmiedebergs Arch Pharmacol . 2004 Jul 30; {Epub ahead of print}
Cloricromene in endotoxemia: role of NF-kappaB; Ianaro A et al.; In this study we investigated, for the first time in vivo, the effect of cloricromene, a cumarine derivative, on NF-kappaB activation in endotoxin-treated rats . Endotoxemia was induced in male rats by the intravenous injection of Salmonella typhosa lipopolysaccharide (LPS; 2 mg/kg/i.v.) . In vivo treatment with cloricromene (2 mg/kg/i.v.) 30 min before lipopolysaccharide administration reversed the LPS-induced loss in tone of the aortic rings, improved their reactivity to phenylephrine, decreased both nitric oxide (NO) and TNF-alpha serum levels by inhibiting LPS-induced inducible NO synthase and TNF-alpha mRNA expression, and interestingly inhibited LPS-induced NF-kappaB activation . Our data suggest that cloricromene protects rats from LPS by blocking LPS-induced NF-kappaB activation, leading to inhibition of NO and TNF-alpha overproduction and thereby reversing the LPS-induced vascular hyporeactivity.

Vet Microbiol, 2004 Aug 19, 102(1-2), 73 - 85
The O-antigen of Salmonella enterica serotype Enteritidis PT4: a significant factor in gastrointestinal colonisation of young but not newly hatched chicks; Carroll P et al.; The lipopolysaccharide of Salmonella and other Gram negative pathogenic species has been implicated as a major virulence determinant and in this study we report the role of LPS of S . Enteritidis in the colonisation and persistent gastrointestinal infection of young poultry . The gene encoding the unique O-antigen ligase, waaL, was mutated by insertional inactivation in a well characterised S . Enteritidis strain, S1400/94 . The waaL mutant, designated PCP, produced rough colonies on agar medium, did not agglutinate O9 antiserum, did not produce an LPS ladder on silver stained gels and was serum sensitive . PCP and a nalidixic acid marked derivative of S1400/94 (S1400/94 Nalr) were used to orally challenge young chicks, separately and together in competitive index experiments . At post-mortem examination of 1-day-old chicks challenged S1400/94 Nalr and PCP separately there were no significant differences in the numbers of S1400/94 Nalr and PCP bacteria in tissues sampled on days 1, 2, and 5 . By day 42 after challenge S1400/94 Nalr bacteria were recovered in significantly higher numbers than PCP from the caecal contents (P < 0.001) . In competitive index studies in the 1-day-old chick PCP colonised, invaded and persisted in lower numbers than S1400/94 Nalr . In 4-week-old chicks challenged separately, PCP bacteria were recovered from all tissues examined in significantly lower numbers than S1400/94 Nalr . In competitive index experiments in 4-week-old chicks, PCP was not detected at any site and at any time point . Therefore, the O-antigen of S . Enteritidis plays an important role in poultry infections although this role is less important in the newly hatched chick.

Prostaglandins Other Lipid Mediat, 2004 Apr, 73(3-4), 265 - 78
Do calcium-mediated cellular signalling pathways, prostaglandin E2 (PGE2), estrogen or progesterone receptor antagonists, or bacterial endotoxins affect bovine placental function in vitro?
Weems YS, Randel RD, Carstens GE, Welsh TH Jr, Weems CW.
The major objective of this experiment was to determine whether the bovine placenta could be stimulated to secrete progesterone, since the bovine placenta secretes little progesterone when the corpus luteum is functional . Secondly, we wanted to determine whether reported abortifacients or progesterone or estrogen receptor antagonists affected bovine placental prostaglandin secretion . The ovine placenta secretes half of the circulating progesterone at day 90 of pregnancy and PGE2 appears to regulate ovine placental progesterone secretion . Calcium has been reported to regulate placental progesterone secretion in cattle . Diced 186-245-day placental slice explants from six Brahman and six Angus cows were incubated in vitro at 39.5 degrees C under 95% air: 5% CO2 at pH 7.2 in 5 ml of M-199 for 1 h in the absence of treatments and for 4 and 8 h in the presence of treatments . Treatments were: vehicle; R24571; compound 48/80; IP3; PGE2; CaCl2; cyclosporin A; lipopolysaccharide (endotoxin) from Salmonella abortus equi., enteriditis, and typhimurium; monensin; ionomycin; arachidonic acid; mimosine; palmitic acid; progesterone, androstenedione; estradiol-17beta; A23187; RU-486; or MER-25 . Jugular and uterine venous plasma and culture media were analyzed for progesterone, PGE2 and PGF2alpha by radioimmunoassay (RIA) . Plasma hormone data were analyzed by a One-Way Analysis of Variance (ANOVA) . Hormone data in culture media were analyzed for breed and treatment effects by a Factorial Design (2 breeds, 2-range of days, 21 treatments) for ANOVA (2 x 2 x 21) . Since hormone data secreted by placental tissue in vitro did not differ (P > or = 0.05) by breed or range of days of pregnancy, data were pooled and analyzed by a One-Way ANOVA . Concentrations of PGE2 in uterine venous blood were two-fold greater (P < or = 0.05) in Angus than Brahman cows . PGE2 and PGF2alpha in vehicle controls increased from 4 to 8h (P < or = 0.05), but not progesterone (P > or = 0.05) Progesterone in culture media treated with RU-486 increased (P < or = 0.05) at 4 and 8 h compared to vehicle controls and was not affected by other treatments (P > or = 0.05) . Concentrations of PGE2 in media at 4 and 8 h were lower (P < or = 0.05) when compared to controls except treatment with PGE2 at 4 and 8h and RU-486 at 8h (P > or = 0.05) . PGF2alpha was increased (P < or = 0.05) by RU-486 at 8h and no other treatment affected PGF2alpha at 4 or 8 h (P < or = 0.05) . In conclusion, modulators of cellular calcium signalling pathways given alone do not affect bovine placental progesterone secretion at the days studied and progesterone receptor-mediated events appear to suppress placental progesterone, PGF2alpha, and PGE2 secretion in cattle . In addition, PGE2 does not appear to regulate bovine placental progesterone secretion when the corpus luteum is functional and bacterial endotoxin does not appear to affect bovine placental secretion of PGF2alpha or PGE2.

Rev Inst Med Trop Sao Paulo, 2004 May-Jun, 46(3), 169 - 70 Epub 2004 Jul 20.
Salmonella enterica subsp houtenae serogroup O:16 in a HIV positive patient: case report; Lourenco MC et al.; We described a case of salmonellosis in a 33-year old HIV-infected patient . The patient presented oral and esophageal candidiasis, intense epigastric and retrosternal pain . During the physical examination he was hypochloraemic, acyanotic, hypohydrated, anicteric and afebrile . Admittance laboratory tests indicated: red cells 3.6 millions/mm(3); hemoglobin, 10.1 g/dL; leukocyte count, 3,000/mm(3), with 1% of eosinophils, 14% of non-segmented and 53% of segmented neutrophils and 31% of lymphocytes . The blood culture was positive for Salmonella enterica subsp houtenae serogroup O:16 . This is probably the first human report of bacteremia due to Salmonella enterica subsp houtenae in Brazil associated to HIV-infected patient.

Poult Sci, 2004 Jul, 83(7), 1218 - 25
Thermal inactivation of Salmonella and Listeria monocytogenes in ground chicken thigh/leg meat and skin; Murphy RY et al.; Thermal inactivation D and z values of Salmonella and Listeria monocytogenes were obtained for chicken thigh and leg meat and skin . The D values of Salmonella at 55 to 70 degrees C were 43.33 to 0.07 min in the meat and 43.76 to 0.09 min in the skin . The D values of L . monocytogenes at 55 to 70 degrees C were 38.94 to 0.04 min in the meat and 34.05 to 0.05 min in the skin . The z value of Salmonella was 5.34 degrees C in the meat and 5.56 degrees C in the skin . The z value of L . monocytogenes was 5.08 degrees C in the meat and 5.27 degrees C in the skin . For Salmonella or L . monocytogenes, the z value of the meat was not different from that of skin . However, the z value of Salmonella in meat or skin was different from that of L . monocytogenes in meat or skin . The z value of Salmonella or L . monocytogenes in chicken thigh and leg meat was different from that in the skin . The results from this study are useful for predicting process lethality of Salmonella and L . monocytogenes in products that contain chicken thigh and leg meat or skin.

Poult Sci, 2004 Jul, 83(7), 1133 - 9
Differential effects of lipopolysaccharide and lipoteichoic acid on the primary antibody response to keyhole limpet hemocyanin of chickens selected for high or low antibody responses to sheep red blood cells; Parmentier HK et al.; Various bacterial components are potent activators of the innate immune system and probably (in)directly determine subsequent specific immune responses . Therefore, effects of i.v . administered Salmonella enteriditis-derived lipopolysaccharide (LPS) and Staphylococcus aureus-derived lipoteichoic acid (LTA), respectively, on the primary antibody (Ab) response to keyhole limpet hemocyanin (KLH) were studied in cocks from 2 lines divergently selected for high (H line) and low (L line) Ab responses to SRBC . The Ab responses to KLH were significantly affected by a line-by-treatment-by-time interaction . Significantly higher Ab titers to KLH, S . aureus LTA, and S . enteriditis LPS were found in H line birds than in the L line birds . Ab titers to KLH were enhanced if the chickens were intravenously pretreated 24 h earlier with LTA but decreased if the chickens were intravenously pretreated 24 h earlier with LPS . Ab responses to S . enteriditis LPS were significantly enhanced when birds were immunized with KLH or pretreated with S . aureus LTA . Ab responses to S . aureus LTA were also significantly enhanced when birds were immunized with KLH or pretreated with LTA and subsequently immunized with KLH . Our findings suggest that LTA and LPS have immunomodulatory features in chickens, albeit in opposite directions . In addition, KLH acted in an immunomodulatory role too . Possible mechanisms underlying our observations and the role of LTA and LPS in polarization of the specific immune response in chickens are discussed.

Poult Sci, 2004 Jul, 83(7), 1112 - 6
Comparison of four Salmonella isolation techniques in four different inoculated matrices; Rybolt ML et al.; The poultry industry is now operating under increased regulatory pressure following the introduction of the pathogen reduction and hazard analysis critical control point (HACCP) rule in 1996 . This new operation scheme has greatly increased the need for on-farm food safety risk management of foodborne bacteria, such as Salmonella . Information needed to make informed food safety risk management decisions must be obtained from accurate risk assessments, which rely on the sensitivity of the isolation techniques used to identify Salmonella in the production environment . Therefore, better characterization of the Salmonella isolation and identification techniques is warranted . One new technique, immunomagnetic separation (IMS), may offer a benefit to the poultry industry, as it has been shown to be efficacious in the isolation of Salmonella from various sample matrices, including some poultry products . In this work, we compared the isolation ability of 4 Salmonella-specific protocols: IMS, tetrathionate (TT) broth, Rappaport-Vassiliadis R10 (RV) broth, and a secondary enrichment (TR) procedure . All 4 methods were compared in 4 different spiked sample matrices: Butterfield's, poultry litter, broiler crops, and carcass rinses . IMS was able to detect Salmonella at 3.66, 2.09, 3.06, and 3.97 log10 cfu/mL in Butterfield's, poultry litter, carcass rinse, and broiler crop matrices, respectively . For the broiler litter and Butterfield's solution, there were no (P > 0.05) differences among the 4 isolation protocols . However, in the carcass rinse and crop samples, there were no differences among the isolation of Salmonella using RV, TR, or TT, but all 3 were (P < or = 0.05) more successful at recovering Salmonella than the IMS method.

Poult Sci, 2004 Jul, 83(7), 1106 - 11
Evaluation of culture media for detecting airborne Salmonella enteritidis collected with an electrostatic sampling device from the environment of experimentally infected laying hens; Gast RK et al.; Detection of Salmonella enteritidis in the environment of commercial laying hens is critical for reducing the production of contaminated eggs by infected flocks . In the present study, an inexpensive and portable electrostatic air sampling device was used to collect S . enteritidis in rooms containing experimentally infected laying hens . After hens were orally inoculated with a phage type 13a S . enteritidis strain and housed in individual cages, air samples were collected 3 times each week with electrostatic devices onto plates of 6 types of culture media (brilliant green agar, modified lysine iron agar, modified semisolid Rappaport-Vassiliadis agar, Rambach agar, XLD agar, and XLT4 agar) . Air sampling plates were incubated at 37 degrees C, examined visually for presumptive identification of typical S . enteritidis colonies and then subjected to confirmatory enrichment culturing . Air samples (collected using all 6 culture media) were positive for S . enteritidis for 3 wk postinoculation . Because visual determination of the presence or absence of typical S . enteritidis colonies on air sampling plates was not consistently confirmed by enrichment culturing, the postenrichment results were used for comparing sampling strategies . The frequency of positive air sampling results using brilliant green agar (66.7% overall) was significantly greater than was obtained using most other media . A combination of several plating media (brilliant green agar, modified lysine iron agar, and XLT4 agar) allowed detection of airborne S . enteritidis at an overall frequency of 83.3% over the 3 wk of sampling . When used with appropriate culture media, electrostatic collection of airborne S . enteritidis can provide a sensitive alternative to traditional methods for detecting this pathogen in the environment of laying flocks.

Avian Dis, 2004 Apr-Jun, 48(2), 384 - 91
Interactions of butyric acid- and acetic acid-treated Salmonella with chicken primary cecal epithelial cells in vitro; Van Immerseel F et al.; In vitro studies of the interaction between pathogenic bacteria and the chicken intestinal epithelium are hampered by the lack of a host- and tissue-specific in vitro model . Therefore, a reproducible method for isolation and cultivation of chicken primary cecal epithelial cells was developed . Cecal crypts were isolated and cultured in vitro to form a semiconfluent layer of epithelial cells . Incubation of Salmonella enteritidis with these cells resulted in invasion . Pretreatment of the Salmonella bacteria with butyric acid resulted in a significant decrease of invasion of the bacteria in the chicken cecal epithelial cells, whereas pretreatment with acetic acid increased invasiveness . These interactions of S . enteritidis with primary chicken cecal epithelial cells were similar to the interactions with other epithelial cell types.

Avian Dis, 2004 Apr-Jun, 48(2), 344 - 50
Phenotypic and genotypic characterization of Salmonella arizonae from an integrated turkey operation; Crespo R et al.; Fifty cases submitted between 2000 and 2002 were selected for retrospective analysis to evaluate possible relationships between Salmonella arizonae isolated from breeder flocks, hatching eggs, and meat bird flocks belonging to a single turkey integrator . In all the meat bird cases selected for this study, arizonosis was the primary diagnosis . In birds under 1 month of age, clinical signs and pathologic changes were observed in older birds . The Salmonella arizonae isolates were analyzed by antibiotic resistance pattern and serotype and genotyped by pulsed-field gel electrophoresis (PFGE) . Serotyping and PFGE yielded similar results, but the antibiotic resistance patterns did not correspond to either serotyping or PFGE typing . The presence of common pulsed-field patterns in breeder flocks, eggs, and meat bird flocks suggested that S . arizonae was being transmitted vertically from the breeder flock.

Avian Dis, 2004 Apr-Jun, 48(2), 244 - 53
Nitric oxide production by macrophages stimulated with Coccidia sporozoites, lipopolysaccharide, or interferon-gamma, and its dynamic changes in SC and TK strains of chickens infected with Eimeria tenella; Lillehoj HS et al.; Nitric oxide (NO) is an important mediator of innate and acquired immunities . In the studies reported here, we quantified NO produced in vitro by chicken leukocytes and macrophages and in vivo during the course of experimental infection with Eimeria, the causative agent of avian coccidiosis, and identified macrophages as the primary source of inducible NO . Eimeria tenella-infected chickens produced higher levels of NO compared with noninfected controls . In Eimeria-infected animals, SC chickens produced greater amounts of NO compared with infected TK chickens, particularly in the intestinal cecum, the region of the intestine infected by E . tenella . Macrophages that were isolated from normal spleen were a major source of NO induced by interferon (IFN)-gamma, lipopolysaccharide (LPS), and E . tenella sporozoites . Macrophage cell line MQ-NCSU produced high levels of NO in response to Escherichia coli or Salmonella typhi LPS, whereas the HD-11 macrophage cell line was more responsive to IFN-gamma . These findings are discussed in the context of the genetic differences in SC and TK chickens that may contribute to their divergent disease phenotypes.

Int J Food Microbiol, 2004 Sep 1, 95(2), 177 - 87
Application of a molecular beacon-real-time PCR technology to detect Salmonella species contaminating fruits and vegetables; Liming SH et al.; An oligonucleotide probe that becomes fluorescent upon hybridization to the target DNA (molecular beacon; MB) was evaluated in a real-time polymerase chain reaction (PCR) assay to detect the presence of Salmonella species . As few as 1-4 colony-forming units (CFU) per PCR reaction could be detected . The capability of the assay to detect Salmonella species from artificially inoculated fresh-cut produce such as cantaloupe, mixed-salad, cilantro, and alfalfa sprouts was demonstrated . A comparison of two commercially available kits utilizing MB-PCR (iQ-Check, Bio-Rad Laboratories) and conventional Association of Official Analytical Chemists (AOAC)-approved PCR (BAX, Dupont Qualicon) was performed on artificially inoculated produce . As few as 4 CFU/25 g of produce were detected after 16 h of enrichment in buffered peptone broth . These assays could be carried out entirely in sealed PCR tubes, enabling a rapid and high-throughput detection of Salmonella species in a large number of food and environmental samples . This is the first report of the application of MB probe being used for real-time detection of Salmonella species in whole and fresh-cut fruits and vegetables.

Int J Food Microbiol, 2004 Sep 1, 95(2), 137 - 46
Effect of hydrogen peroxide treatment on microbial quality and appearance of whole and fresh-cut melons contaminated with Salmonella spp; Ukuku DO; The efficacy of hydrogen peroxide treatment on the inactivation of Salmonella spp . inoculated on the external surface of cantaloupe and honeydew melon was investigated . Salmonella was inoculated onto whole cantaloupe and honeydew melon to a final concentration of 4.65 log(10) CFU/cm(2) and 3.13 log(10) CFU/g, respectively . Inoculated whole melons stored at 5 degrees C for up to 7 days were washed with water, 2.5% and 5% hydrogen peroxide at day 0 and 5 . Hydrogen peroxide (2.5% and 5%) treatments of whole melon for 5 min caused a 3 log(10) CFU/cm(2) reduction of the indigenous surface microflora and a 3.0 log(10) CFU/cm(2) reduction in Salmonella spp . on all melon surfaces . The efficacy of the hydrogen peroxide treatments was less when the interval between inoculation and treatment of cantaloupe exceeded 24 h . Unlike cantaloupe fresh-cut pieces, Salmonella was not recovered from fresh-cut pieces prepared from treated whole honeydew melon . Growth of Salmonella occurred in cantaloupe fresh-cut pieces stored at 10 or 20 degrees C, and by 2 weeks, levels reached approximately 1 log CFU/g . A rapid decline in appearance and overall acceptability was observed in fresh-cut pieces prepared from untreated whole cantaloupe . While Salmonella was recovered from fresh-cut pieces from and whole treated cantaloupe, sanitizing the surface of contaminated whole melons with hydrogen peroxide before and after cutting and storage of the fresh-cut pieces at 5 degrees C can enhance the microbial safety and acceptability rating for about 2 weeks after processing.

J Appl Microbiol, 2004, 97(3), 617 - 20
Effect of sunlight on the survival of Salmonella on surfaces; Nyeleti C et al.; AIMS: To investigate the effect of simulated full-spectrum tropical sunlight on the survival of Salmonella in droplets on surfaces . MATERIALS AND RESULTS: The survival on surfaces of three Zambian strains of Salmonella enterica serovars Enteritidis and Heidelberg was compared with that of a strain of S . enterica serovar Enteritidis phage type (PT) 4 with known characteristics which had been isolated from poultry in the UK . Samples were taken from surfaces every hour for 3 h and after 24 h exposure in either dark or 12 h light/12 h dark cycle conditions . Differences were analysed for significance using a one-way analysis of variance (anova) . Results show that there were a significantly higher number of cells surviving on surfaces after 24 h in the dark when compared with populations exposed to a 12 h light/12 h dark cycle . Significantly more cells also survived exposure to sunlight under dirty than clean conditions . CONCLUSIONS: Exposure to sunlight results in a significant decrease in numbers of Salmonella on surfaces . SIGNIFICANCE AND IMPACT OF THE STUDY: Under field conditions exposure of contaminated surfaces to sunlight could be used in place of chemical methods of control as a cheaper way to reduce Salmonella contamination of surfaces .

J Appl Microbiol, 2004, 97(3), 566 - 73
Population structure of Salmonella investigated by amplified fragment length polymorphism; Torpdahl M et al.; AIMS: This study was undertaken to investigate the usefulness of amplified fragment length polymorphism (AFLP) in determining the population structure of Salmonella . METHODS AND RESULTS: A total of 89 strains were subjected to AFLP analysis using the enzymes BglII and BspDI, a combination that is novel in Salmonella . Both species S . bongori and S . enterica and all subsp . of S . enterica were represented with emphasis on S . enterica subsp . enterica using a local strain collection and strains from the Salmonella Reference Collection B (SARB) . The amplified fragments were used in a band-based cluster analysis . The tree resulting from the subgroup analysis clearly separated all subgroups with high bootstrap values with the species S . bongori being the most distantly related of the subgroups . The tree resulting from the analysis of the SARB collection showed that some serotypes are very clonal whereas others are highly divergent . CONCLUSIONS: AFLP clearly clustered strains representing the subgroups of Salmonella together with high bootstrap values and the serotypes of subspecies enterica were divided into polyphyletic or monophyletic types corresponding well with multilocus enzyme electrophoresis (MLEE) and sequence-based studies of the population structure in Salmonella . SIGNIFICANCE AND IMPACT OF THE STUDY: AFLP with the enzyme combination BglII and BspDI allows discrimination of individual strains and provides evidence for the usefulness of AFLP in studies of population structure in Salmonella .

Genetics, 2004 Jul, 167(3), 1069 - 77
Insertions of mini-Tn10 transposon T-POP in Salmonella enterica sv . typhi; Hidalgo AA et al.; We have mutagenized a clinical strain of Salmonella enterica sv . typhi with mini-transposon Tn10dTet (T-POP) to obtain conditional lethal (tetracycline-dependent) mutants with T-POP insertions upstream of essential genes . Generalized transducing phage P22 was used to introduce T-POP from a S . typhimurium donor into a S . typhi recipient . Chromosomal DNA was purified from the mutagenized donor strains, fragmented, and then electroporated into S . typhi to backcross the original T-POP insertions . Four tetracycline-dependent mutants with two distinct terminal phenotypes were found among 1700 mutants with T-POP insertions . When grown in the absence of tetracycline, two of the four tetracycline-dependent mutants arrest at a late stage in the cell cycle, can be rescued by outgrowth in media with tetracycline, and define a reversible checkpoint late in the cell cycle . One of these insertions creates an operon fusion with a gene, yqgF, that is conserved among gram-negative bacteria and likely encodes an essential Holliday junction resolvase . T-POP insertions can be used not only to identify essential S . typhi genes but also to reveal novel phenotypes resulting from the depletion of their products.

Mutat Res, 2004 Aug 8, 562(1-2), 39 - 65
Mutagenicity in Salmonella of halonitromethanes: a recently recognized class of disinfection by-products in drinking water; Kundu B et al.; Halonitromethanes (HNMs) are a recently identified class of disinfection by-products (DBPs) in drinking water . They include chloronitromethane (CHN), dichloronitromethane (DCNM), trichloronitromethane (TCNM), bromonitromethane (BNM), dibromonitromethane (DBNM), tribromonitromethane (TBNM), bromochloronitromethane (BCNM),dibromochloronitromethane (DBCNM), and bromodichloronitromethane (BDCNM) . Previous studies of TCNM, DCNM, CNM, and TBNM found that all four were mutagenic in bacteria, and a recent study showed that all nine induced DNA damage in CHO cells . Here, all nine HNMs were evaluated in the Salmonella plate-incorporation assay +/- S9 using strains TA98, TA100, TA104, TPT100, and the glutathione transferase theta (GSTT1-1)-expressing strain RSJ100 . All were mutagenic, most with and without S9 . In the absence of S9, six were mutagenic in TA98, six in TA100, and three in TA104; in the presence of S9, these numbers were five, seven, and three, respectively . Thus, the HNMs-induced base substitutions primarily at GC sites as well as frameshifts . Although five HNMs were activated to mutagens in RSJ100 -S9, they produced < or =2-fold increases in revertants and potencies <506 rev/micromol . The rank order of the HNMs by mutagenic potency in TA100 +S9 was (BCNM DBNM) > (TBNM CNM > BNM DCNM BDCNM) > (TCNM = DBCNM) . The mean rev/micromol for the three groupings, respectively, were 1423, 498, and 0, which classifies the HNMs as weak mutagens in Salmonella . Reaction of the dihalo and monohalo HNMs with GSH, possibly GSTT1-1, is a possible mechanism for formation of ultimate mutagenic products . Because the HNMs are mutagenic in Salmonella (present study) and potent clastogens in mammalian cells {Environ . Sci . Technol . 38 (2004) 62}, their presence in drinking water warrants further research on their potential health effects.

J Coll Physicians Surg Pak, 2004 Jul, 14(7), 433 - 5
Salmonella osteomyelitis; Ahmed A et al.; A case report of a young girl with salmonella osteomyelitis of left radius is presented having no constitutional symptoms . X-ray, changes are described . Curettage tissue sent for culture and histology . Histology showed non-specific osteomyelitis while salmonella was grown . She was treated accordingly and got cured with three year follow-up.

J Coll Physicians Surg Pak, 2004 Jul, 14(7), 404 - 6
Hematological evaluation of splenomegaly; Ali N et al.; OBJECTIVE: To find out the relative frequency of clinical conditions associated with splenomegaly that require hematological evaluation in our set up . DESIGN: Cross sectional study . PLACE AND DURATION OF STUDY: Combined Military Hospital, Quetta, Balochistan, from July 2000 to July 2003 . SUBJECTS AND METHODS: Patients of either gender and all age groups with palpable spleen were included . Patients with splenomegaly due to liver disease, malarial parasites on thick or thin blood film, positive Widal test, or positive blood cultures were excluded from study . Patients were initially evaluated with clinical history, microscopic examination of blood smear, and blood counts . Depending upon provisional diagnosis bone marrow examination or investigations for hemolytic anemia were performed . RESULTS: One hundred patients were received . Seventy-eight patients were adults and 22 patients were of pediatric age group . In the adults, hematological malignancies were seen in 37%, malarial parasites in bone marrow in 20.5%, megaloblastic anemia in 13%, bacterial infections in 9%, hemolytic anemia in 9%, tropical splenomegaly in 5%, and positive bone marrow culture for salmonella in 6.5% . In children, hematological evaluation revealed hematological malignancies in 18%, beta thalassaemia in 55%, other hemolytic anemias in 13.5%, congenital sideroblastic anemia in 4.5%, and storage disorder in 9% . CONCLUSION: Hematological workup is informative in most of the cases . Bone marrow examination is the key investigation, hematological malignancies constituted 37% of the adult and 18% of pediatric age group patients . Hemolytic anemia constituted 68% of pediatric age group.

J Formos Med Assoc, 2004 Jun, 103(6), 463 - 6
Mesenteric adenitis caused by Salmonella enterica serovar Enteritidis; Lee CC et al.; Mesenteric adenitis is a self-limited condition characterized by fever, localized right lower quadrant abdominal pain, and frequent leukocytosis, making it difficult to differentiate from appendicitis . We report a case of mesenteric adenitis in an 8-year-old boy who presented at the emergency department with right lower quadrant abdominal pain, diarrhea, and fever up to 40 degrees C . Acute appendicitis was initially suspected, but further abdominal ultrasound and contrast enhanced computed tomography studies showed a normal appendix with marked mesenteric adenopathy . Symptomatic treatment was given and pain and fever subsided 2 days later . Follow-up sonography showed resolution of adenopathy, confirming the diagnosis of mesenteric adenitis . The admission stool cultures grew Salmonella enterica serovar Enteritidis (S . Enteritidis) . Unlike previous reports in western countries where Yersinia species prevails and was thought to be self-limited, S . Enteritidis carries potential risk for serious systemic complications, such as meningitis or septic arthritis . The isolation of this unusual microbiological species thus has both therapeutic and epidemiological implications for mesenteric adenitis in Taiwan.

Am J Clin Nutr, 2004 Aug, 80(2), 453 - 9
Birth weight predicts response to vaccination in adults born in an urban slum in Lahore, Pakistan; Moore SE et al.; BACKGROUND: Substantial evidence exists linking small size at birth to later-life susceptibility to chronic disease . Evidence is also emerging that some components of immune function may be programmed in early life . However, this evidence is limited and requires confirmation . OBJECTIVE: We investigated the association between size at birth and response to vaccination in a cohort of 257 adults (mean age: 29.4 y; 146 men) born in an urban slum in Lahore, Pakistan, during 1964-1978 . DESIGN: A single dose of Vi polysaccharide vaccine for Salmonella typhi and 2 doses of rabies vaccine were given to each subject . Antibody titers were measured in prevaccination serum samples (Vi) and in postvaccination samples (Vi and rabies) . RESULTS: The mean birth weight of the subjects was 3.24 kg; 14% of the subjects had low birth weights (<2.5 kg) . Vaccine responses were not consistently associated with contemporary variables (month of study, sex, current age, or indicators of wealth) . Response to typhoid vaccination was positively related to birth weight (anti-Vi immunoglobulin G: r = 0.138, P = 0.031; anti-Vi immunoglobulin M: r = 0.197, P = 0.034) . Response to the rabies vaccine was not significantly associated with birth weight . CONCLUSIONS: These findings add to a growing body of evidence suggesting that components of the immune system may be permanently programmed by events in early life . The contrasting effects on typhoid and rabies responses suggest that antibody generation to polysaccharide antigens, which have greater B cell involvement, is compromised by fetal growth retardation.

Avian Pathol, 2004, 33(2), 251 - 257
Salmonella gallinarum gyrA mutations associated with fluoroquinolone resistance; Lee YJ et al.; Salmonella enterica subsp . enterica serovar Gallinarum (S . gallinarum) is the causative organism of fowl typhoid, and an outbreak of fowl typhoid in Korea was confirmed in 1992 . The aim of this study was to investigate possible changes in fluoroquinolone susceptibility among S . gallinarum isolates from 1995 to 2001, and to analyse mutations of the gyrA gene in fluoroquinolone-resistant isolates . Among 258 S . gallinarum isolates tested by the disk diffusion method, isolates from 1995 (n=18) were susceptible to all fluoroquinolones tested, whereas a number of isolates from 2001 (n=46) showed reduced susceptibility to enrofloxacin (6.5%), ciprofloxacin (10.9%), norfloxacin (52.5%) and ofloxacin (82.6%) . The minimum inhibitory concentration range of enrofloxacin, ciprofloxacin, norfloxacin, ofloxacin and danofloxacin increased from </=0.06 approximately 0.25 microg/ml in 1995 to 2 approximately 8 microg/ml in 2001 . When amino acid changes in the gyrA were analysed by DNA sequencing, 22.5% and 14.7% among 258 isolates had a mutation at the Ser-83 and Asp-87 codons, respectively, and the prevalence of these mutants increased from 5.6% in 1995 to 89.1% in 2001 . These mutants contained a change from Ser to Phe or Tyr at codon 83, or a change from Asp to Gly, Tyr or Asn at codon 87, and showed a range of minimum inhibitory concentrations of enrofloxacin from 0.5 to 8 microg/ml, ciprofloxacin from 0.25 to 4 microg/ml, norfloxacin from 2 to 32 microg/ml, ofloxacin from 0.5 to 4 microg/ml, and danofloxacin from 0.5 to 4 microg/ml . These results suggested an important association between the gyrA mutations and fluoroquinolone resistance of S . gallinarum . Mutations de gyrA de Salmonella gallinarum associEes a la rEsistance aux fluoroquinolones Salmonella enterica subsp . enterica sErovar Gallinarum (S . gallinarum) est l'agent responsable de la typhose aviaire (FT), et un cas de FT en CorEe a EtE confirmE en 1992 . Le but de cette Etude a EtE d'investiguer les changements possibles de sensibilitE aux fluoroquinolones parmi les souches de S . gallinarum isolEes de 1995 a 2001, et d'analyser les mutations du gene gyrA chez les souches rEsistantes aux fluoroquinolones . Parmi les 258 souches de S . gallinarum testEes par la mEthode de diffusion a partir d'un disque, les souches isolEes en 1995 (n=18) Etaient sensibles vis-a-vis de toutes les fluoroquinolones testEes, alors que les souches isolEes en 2001 (n=46) montraient des sensibilitEs rEduites a l'enrofloxacine (6.5%), a la ciprofloxacine (10.9%), a la norfloxacine (52.5%), a la ofloxacine (82.6%) . Les valeurs des CMI(50), de l'enrofloxacine, la ciprofloxacine, la norfloxacine, la ofloxacine et la danofloxacine ont augmentE de </=0.06 a 0.5 microg/ml en 1995 a 2 a 8 microg/ml en 2001 . Les changements des acides aminEs de la gyrA ont EtE analysEs par sEquenc }}>age de l'ADN et ont rEvElE qu'a partir des 258 souches isolEes, 22.5% et 14.7% d'entre elles prEsentaient une mutation, respectivement aux codons de la Ser-83 et de L'Asp-87 . De plus la prEvalence de ces mutants a augmentE de 5.6% en 1995 a 89.1% en 2001 . Ces mutants prEsentent un changement de la Ser en Phe ou en Tyr au codon 83, ou bien un changement de l'Asp en Gly, en Tyr ou en Asn au codon 87 et ont des variations des CMIs, pour l'enrofloxacine de 0.5 a 8 microg/ml, pour la ciprofloxacine de 0.25 a 4 microg/ml, pour la norfloxacine de 2 a 32 microg/ml, pour l'ofloxacine de 0.5 a 4 microg/ml, et pour la danofloxacine de 0.5 a 4 microg/ml . Ces rEsultats suggerent une importante association entre les mutations de gyrA et de la rEsistance de S . gallinarum aux fluoroquinlones . Mit der Resistenz gegen Fluorquinilon asoziierte Mutationen von Salmonella gallinarum gyrA Salmonella enterica subsp . enterica Serovar Gallinarum (S . gallinarum) ist das kausative Agens des Geflugel-Typhus (FT) . Im Jahr 1992 wurde ein Ausbruch von FT in Korea nachgewiesen . Ziel dieser Studie war es, bei den S . gallinarum-Isolaten aus den Jahren 1995-2001 moglichen Veranderungen hinsichtlich der Empfindlichkeit gegenuber Fluorquinolon zues rÉsultats suggèrent une importante association entre les mutations de gyrA et de la rÉsistance de S . gallinarum aux fluoroquinlones . Mit der Resistenz gegen Fluorquinilon asoziierte Mutationen von Salmonella gallinarum gyrA Salmonella enterica subsp . enterica Serovar Gallinarum (S . gallinarum) ist das kausative Agens des Geflügel-Typhus (FT) . Im Jahr 1992 wurde ein Ausbruch von FT in Korea nachgewiesen . Ziel dieser Studie war es, bei den S . gallinarum-Isolaten aus den Jahren 1995-2001 möglichen Veränderungen hinsichtlich der Empfindlichkeit gegenüber Fluorquinolon zu untersuchen und Mutationen des gyrA-Gens in Fluorquinolon-resistenten Stämmen zu analysieren . Von 258 mittels der Plattendiffusionsmethode untersuchten S . gallinarum-Isolaten waren nur wenige Isolate aus dem Jahr 1995 (n=18) empfindlich gegenüber allen getesteten Fluorquinolonen, während einige Isolate aus dem Jahr 2001 (n=46) eine reduzierte Empfindlichkeit gegenüber Enrofloxazin (6.5 %), Ciprofloxazin (10.9 %), Norfloxazin (52.5 %) und Ofloxazin (82.6 %) aufwiesen . Das MIC(50)-Spektrum stieg bei Enrofloxazin, Ciprofloxazin, Norfloazin, Ofloxazin und Danofloxazin von <}}> 0.06-0.5 μg/ml im Jahr 1995 auf 2-8 μg/ml im Jahr 2001 an . Bei der Analyse der Aminosäurenänderungen im gyrA mittels DNS-Sequenzierung hatten 22.5 % der 258 Isolate eine Mutation am Ser-83 und 14.7 % am Asp-87, und die Prävalenz dieser Mutanten nahm von 5.6 % im Jahr 1995 auf 89.1 % im Jahr 2001 zu . Diese Mutanten wiesen einen Wechsel von Ser zu Phe oder Tyr am Kodon 83 oder einen Wechsel von Asp to Gly, Tyr oder Asn am Kodon 87 auf und zeigten ein MIC-Spektrum des Enrofloxazins von 0.5-8 μg/ml, des Ciprofloxazins von 0.25-4 μg/ml, des Norfloxazins von 2-32 μg/ml, des Ofloxazins von 0.5-4 μg/ml und des Danofloxazins von 0.5-4 μg/ml . Diese Ergebnisse lassen vermuten, dass eine wichtige Beziehung zwischen den gyrA-Mutationen und der Fluorquinolon-Resistenz von S . gallinarum besteht . Mutaciones en Salmonella gallinarum gyrA asociadas a resistencia a la fluoroquinolonas Salmonella enterica subsp . enterica serovar Gallinarum (S . gallinarum) es el microorganismo que causa el tifus aviar (FT), y un brote de FT en Corea se confirmó en 1992 . El objetivo de este estudio es investigar posibles cambios en la susceptibilidad a la fluoroquinolonas entre las cepas de S . gallinarum aisladas del 1995 al 2001, y analizar mutaciones del gen gyrA en los aislados resistentes a las fluoroquinolonas . Entre los 258 aislados de S . gallinarum evaluados mediante un mÉtodo de difusión de disco, un aislado de 1995 (n=18) fue susceptible a todas las fluoroquinolonas probadas, mientras que algunos de los aislados del 2001 (n=46) mostraron una susceptibilidad reducida a la enrofloxacina (6.5%), ciprofloxacina (10.9%), norfloxacina (52.5%) y ofloxacina (82.6%) . El rango de MIC(50)s de la enrofloxacina, ciprofloxacina, norfloxacina, ofloxacina y danofloxacina incrementó de ≤0.06 a 0.5 μg/ml en 1995 a, 2 a 8 μg/ml en 2001 . Cuando los cambios aminoacídicos en el gyrA fueron analizados mediante secuenciación del ADN, 22.5% y 14.7% de entre los 258 aislados presentaron mutaciones en los codones Ser-83 y Asp-87, respectivamente, y la prevalencia de estos mutantes incrementó de 5.6% en 1995 a 89.1% en el 2001 . Estos mutantes contenían un cambio de Ser a Phe o Tyr en el codón 83, o un cambio de Asp a Gly, Tyr o Asn en el codón 87, y mostraron un rango de MICs de la enrofloxacina de 0.5 a 8 μg/ml, ciprofloxacina de 0.25 a 4 μg/ml, norfloxacina de 2 a 32 μg/ml, ofloxacina de 0.5 a 4 μg/ml, y danofloxacina de 0.5 a 4 μg/ml . Estos resultados sugieren que S . gallinarum presenta una importante asociación entre las mutaciones en gyrA y la resistencia a fluoroquinolonas.

J Mol Biol, 2004 Aug 6, 341(2), 491 - 502
Domain organization and function of Salmonella FliK, a flagellar hook-length control protein; Minamino T et al.; Salmonella hook-length control protein FliK, which consists of 405 amino acid residues, switches substrate specificity of the type III flagellar protein export apparatus from rod/ hook-type to filament-type by causing a conformational change in the cytoplasmic domain of FlhB (FlhB(C)) upon completion of the hook assembly . An N-terminal region of FliK contains an export signal, and a highly conserved C-terminal region consisting of amino acid residues 265-405 (FliK((265-405))) is directly involved in the switching of FlhB(C) . Here, we have investigated the structural properties of FliK . Gel filtration chromatography, multi-angle light scattering and analytical ultracentrifugation showed that FliK is monomeric in solution and has an elongated shape . Limited proteolysis showed that FliK consists of two domains, the N-terminal (FliK(N)) and C-terminal domains (FliK(C)), and that the first 203 and the last 35 amino acid residues are partially unfolded and subjected to proteolysis . Both FliK(N) and FliK(C) are more globular than full-length FliK, suggesting that these domains are connected in tandem . Overproduced His-FliK((199-405)) failed to switch export specificity of the export apparatus . Affinity blotting revealed that FlhB(C) binds to FliK and FliK((1-147)), but not to FliK((265-405)) . Based on these results, we propose that FliK(N) within the central channel of the hook-basal body during the export of FliK is the sensor and transmitter of hook completion information and that the binding interaction of FliK(C) to FlhB(C) is structurally regulated by FliK(N) so as to occur only when the hook has reached a preset length . The conformational flexibility of FliK(C) may play a role in interfering with switching at an inappropriate point of flagellar assembly.

Fish Shellfish Immunol, 2004 Sep, 17(3), 223 - 33
Flow cytometric analysis of crayfish haemocytes activated by lipopolysaccharides; Cardenas W et al.; Lipopolysaccharides (LPS) from Gram-negative bacteria are strong stimulators of white river crayfish, Procambarus zonangulus, haemocytes in vitro . Following haemocyte treatment with LPS and with LPS from rough mutant R5 (LPS Rc) from Salmonella minnesota, flow cytometric analysis revealed a conspicuous and reproducible decrease in cell size as compared to control haemocytes . These LPS molecules also caused a reduction in haemocyte viability as assessed by flow cytometry with the fluorescent dyes calcein-AM and ethidium homodimer . The onset of cell size reduction was gradual and occurred prior to cell death . Haemocytes treated with LPS from S . minnesota without the Lipid A moiety (detoxified LPS) decreased in size without a reduction of viability . The action of LPS on crayfish haemocytes appeared to be related to the activation of the prophenoloxidase system because phenoloxidase (PO)-specific activity in the supernatants from control and detoxified LPS-treated cells was significantly lower than that from LPS and LPS-Rc treated cells (P</=0.05) . Furthermore, addition of trypsin inhibitor to the LPS treatments caused noticeable delays in cell size and viability changes . These patterns of cellular activation by LPS formulations indicated that crayfish haemocytes react differently to the polysaccharide and lipid A moieties of LPS, where lipid A is cytotoxic and the polysaccharide portion is stimulatory . These effects concur with the general pattern of mammalian cell activation by LPS, thereby indicating common innate immune recognition mechanisms to bacterial antigens between cells from mammals and invertebrates . These definitive molecular approaches used to verify and identify mechanisms of invertebrate haemocyte responses to LPS could be applied with other glycoconjugates, soluble mediators, or xenobiotic compounds.

Antimicrob Agents Chemother, 2004 Aug, 48(8), 3179 - 81
Extended-spectrum-cephalosporin resistance in Salmonella enterica isolates of animal origin; Gray JT et al.; A total of 112 out of 5,709 Salmonella enterica isolates from domestic animal species exhibited decreased susceptibilities to ceftiofur and ceftriaxone, and each possessed the blaCMY gene . Ten Salmonella serotypes were significantly more likely to include resistant isolates . Isolates from turkeys, horses, cats, and dogs were significantly more likely to include resistant isolates.

Antimicrob Agents Chemother, 2004 Aug, 48(8), 2845 - 52
DNA sequence analysis of regions surrounding blaCMY-2 from multiple Salmonella plasmid backbones; Giles WP et al.; The emergence in the United States of resistance to expanded-spectrum cephalosporin (e.g., ceftriaxone) within the salmonellae has been associated primarily with three large (>100-kb) plasmids (designated types A, B, and C) and one 10.1-kb plasmid (type D) that carry the blaCMY-2 gene . In the present study, the distribution of these four known blaCMY-2-carrying plasmids among 35 ceftriaxone-resistant Salmonella isolates obtained from 1998 to 2001 was examined . Twenty-three of these isolates were Salmonella enterica serotype Newport, 10 were Salmonella enterica serotype Typhimurium, 1 was Salmonella enterica serotype Agona, and 1 was Salmonella enterica serotype Reading . All 23 serotype Newport isolates carried a type C plasmid, and 5, 4, and 1 serovar Typhimurium isolate carried type B, A, and C plasmids, respectively . Both the serotype Agona and serotype Reading isolates carried type A plasmids . None of the isolates carried a type D plasmid . Hybridization data suggested that plasmid types A and C were highly related replicons . DNA sequencing revealed that the region surrounding blaCMY-2 was highly conserved in all three plasmid types analyzed (types B, C, and D) and was related to a region surrounding blaCMY-5 from the Klebsiella oxytoca plasmid pTKH11 . These findings are consistent with a model in which blaCMY-2 has been disseminated primarily through plasmid transfer, and not by mobilization of the gene itself, to multiple Salmonella chromosomal backbones.

Antimicrob Agents Chemother, 2004 Aug, 48(8), 2808 - 15
Multiple outbreaks of nosocomial salmonellosis in Russia and Belarus caused by a single clone of Salmonella enterica serovar Typhimurium producing an extended-spectrum beta-lactamase; Edelstein M et al.; Thirty-four cefotaxime-resistant Salmonella enterica serovar Typhimurium isolates representative of the isolates that caused outbreaks of gastroenteritis in 10 hospitals in seven regions of Russia and Belarus from 1994 to 2003 were analyzed . All isolates produced the CTX-M-5-like extended-spectrum beta-lactamase, which confers high-level resistance to cefotaxime and ceftriaxone and decreased susceptibility to ceftazidime . The bla(CTX-M) genes were located on small (7.4- to 12-kb) non-self-transferable plasmids approximately 20 bp downstream of the ISEcp1 insertion sequences . Some isolates carried additional conjugative plasmids mediating resistance to penicillin-inhibitor combinations and various non-beta-lactam agents, including tetracycline, chloramphenicol, gentamicin, tobramycin, and co-trimoxazole . Despite the minor differences in susceptibility patterns, all isolates were considered clonally related on the basis of arbitrarily primed PCR and pulsed-field gel electrophoresis analysis . The similarities of the restriction profiles of the CTX-M-coding plasmids further supported the clonal origin of these isolates.

Southeast Asian J Trop Med Public Health, 2004 Mar, 35(1), 92 - 6
Research note: Molecular subtyping of Salmonella enterica serovar Tshiongwe recently isolated in Malaysia during 2001-2002; Thong KL et al.; Pulsed field gel electrophoresis (PFGE) and antimicrobial susceptibility analysis were undertaken on twenty-three strains of Salmonella enterica serovar Tshiongwe, an unusual serovar, which recently emerged in Malaysia . Antimicrobial susceptibility analysis showed that all the strains were sensitive to ampicilin, chloramphenicol, cotrimoxazole, and kanamycin . Twenty (87%) and 8 (3.5%) strains had resistance to tetracycline and streptomycin respectively . PFGE analysis subtyped 23 strains into 10 profiles (Dice coefficient of similarity, F = 0.7-1.0) . The predominant profile, X1 was found in both clinical and environmental isolates and was widely distributed in different parts of Malaysia during the study period . In addition, isolates recovered from food, a hand-towel, apron and the surface of a table-top in one particular location had unique, indistinguishable profiles (X4/4a) and identical antibiograms . Similarly, isolates from cooked meat and a chopping board had PFGE profiles similar to some human isolates . These probably indicated cross-contamination and poor hygiene in food practices, hence contributing to Salmonellosis . Factors causing the emergence of this rare Salmonella serovar being responsible for food poisoning episodes during the study period remained unclear . The study reiterated the usefulness and versatility of PFGE in the molecular subtyping of this rare Salmonella serovar in Malaysia.

Chemotherapy, 2004 Jun, 50(3), 152 - 4
Synergism of ciprofloxacin and trimethoprim against Salmonella enterica serovar typhi isolates showing reduced susceptibility to ciprofloxacin; Mandal S et al.; The activity of the combination of ciprofloxacin and trimethoprim against 16 Salmonella enterica serovar typhi isolates from blood cultures were tested by agar dilution checkerboard technique . When used in combination, minimum inhibitory concentrations (MICs) of ciprofloxacin and trimethoprim ranged from 0.5 to 1.25 and from 10 to 125 microg/ml, respectively, and fractional inhibitory concentrations (FICs) from 0.025 to 0.125 and from 2.5 to 10 microg/ml, respectively . The FIC index was 0.140-0.483, indicating a marked synergy between ciprofloxacin and trimethoprim against trimethoprim-resistant S . enterica serovar typhi isolates (100%) with high MICs for ciprofloxacin.

J Biol Chem, 2004 Sep 24, 279(39), 40505 - 10 Epub 2004 Jul 22.
Mutational analysis of ThiH, a member of the radical S-adenosylmethionine (AdoMet) protein superfamily; Martinez-Gomez NC et al.; Thiamine pyrophosphate (TPP) is an essential cofactor for all forms of life . In Salmonella enterica, the thiH gene product is required for the synthesis of the 4-methyl-5-beta hydroxyethyl-thiazole monophosphate moiety of TPP . ThiH is a member of the radical S-adenosylmethionine (AdoMet) superfamily of proteins that is characterized by the presence of oxygen labile {Fe-S} clusters . Lack of an in vitro activity assay for ThiH has hampered the analysis of this interesting enzyme . We circumvented this problem by using an in vivo activity assay for ThiH . Random and directed mutagenesis of the thiH gene was performed . Analysis of auxotrophic thiH mutants defined two classes, those that required thiazole to make TPP (null mutants) and those with thiamine auxotrophy that was corrected by either L-tyrosine or thiazole (ThiH* mutants) . Increased levels of AdoMet also corrected the thiamine requirement of members of the latter class . Residues required for in vivo function were identified and are discussed in the context of structures available for AdoMet enzymes .

Infect Immun, 2004 Aug, 72(8), 4924 - 8
DNA-Salmonella enterica serovar Typhimurium primer-booster vaccination biases towards T helper 1 responses and enhances protection against Leishmania major infection in mice; Lange UG et al.; Successful resolution of infections by intracellular pathogens requires gamma interferon (IFN-gamma) . DNA vaccines promote T helper 1 (Th1) responses by triggering interleukin-12 (IL-12) release by dendritic cells (DC) through Toll-like receptor 9 (TLR9) . In humans TLR9 is restricted to plasmacytoid DC . Here we show that DNA-Salmonella enterica serovar Typhimurium primer-booster vaccination, which provides alternative ligands to bind TLR4 on myeloid DC, strongly biases towards Th1 responses compared to vaccination with DNA alone . This results in higher immunoglobulin G2a (IgG2a) responses compared to IgG1 responses, higher IFN-gamma responses compared to IL-10 CD4(+)-T-cell responses, and enhanced protection against Leishmania major infection in susceptible BALB/c mice.

Infect Immun, 2004 Aug, 72(8), 4654 - 61
Role of the two-component regulator CpxAR in the virulence of Salmonella enterica serotype Typhimurium; Humphreys S et al.; The CpxAR (Cpx) two-component regulator controls the expression of genes in response to a variety of environmental cues . The Cpx regulator has been implicated in the virulence of several gram-negative pathogens, although a role for Cpx in vivo has not been demonstrated directly . Here we investigate whether positive or negative control of gene expression by Cpx is important for the pathogenesis of Salmonella enterica serotype Typhimurium . The Cpx signal pathway in serotype Typhimurium was disrupted by insertional inactivation of the cpxA and cpxR genes . We also constitutively activated the Cpx pathway by making an internal in-frame deletion in cpxA (a cpxA* mutation) . Activation of the Cpx pathway inhibited induction of the envelope stress response pathway controlled by the alternative sigma factor sigma(E) (encoded by rpoE) . Conversely, the Cpx pathway was highly up-regulated (>40-fold) in a serotype Typhimurium rpoE mutant . The cpxA* mutation, but not the cpxA or the cpxR mutation, significantly reduced the capacity of serotype Typhimurium to adhere to and invade eucaryotic cells, although intracellular replication was not affected . The cpxA and cpxA* mutations significantly impaired the ability of serotype Typhimurium to grow in vivo in mice . To our knowledge, this is the first demonstration that the Cpx system is important for a bacterial pathogen in vivo.

Infect Immun, 2004 Aug, 72(8), 4637 - 46
Mucosally delivered Salmonella live vector vaccines elicit potent immune responses against a foreign antigen in neonatal mice born to naive and immune mothers; Capozzo AV et al.; The development of effective vaccines for neonates and very young infants has been impaired by their weak, short-lived, and Th-2 biased responses and by maternal antibodies that interfere with vaccine take . We investigated the ability of Salmonella enterica serovars Typhi and Typhimurium to mucosally deliver tetanus toxin fragment C (Frag C) as a model antigen in neonatal mice . We hypothesize that Salmonella, by stimulating innate immunity (contributing to adjuvant effects) and inducing Th-1 cytokines, can enhance neonatal dendritic cell maturation and T-cell activation and thereby prime humoral and cell-mediated immunity . We demonstrate for the first time that intranasal immunization of newborn mice with 10(9) CFU of S . enterica serovar Typhi CVD 908-htrA and S . enterica serovar Typhimurium SL3261 carrying plasmid pTETlpp on days 7 and 22 after birth elicits high titers of Frag C antibodies, previously found to protect against tetanus toxin challenge and similar to those observed in adult mice . Salmonella live vectors colonized and persisted primarily in nasal tissue . Mice vaccinated as neonates induced Frag C-specific mucosal and systemic immunoglobulin A (IgA)- and IgG-secreting cells, T-cell proliferative responses, and gamma interferon secretion . A mixed Th1- and Th2-type response to Frag C was established 1 week after the boost and was maintained thereafter . S . enterica serovar Typhi carrying pTETlpp induced Frag C-specific antibodies and cell-mediated immunity in the presence of high levels of maternal antibodies . This is the first report that demonstrates the effectiveness of Salmonella live vector vaccines in early life.

Mol Cell Probes, 2004 Aug, 18(4), 251 - 3
Unexpected detection of DNA by nucleic acid sequence-based amplification technique; Rodriguez-Lazaro D et al.; Nucleic acid sequence-based amplification (NASBA) is a technique that has been previously shown to selectively mediate the detection of RNA in microbial cells . In a series of tests, nucleic acids were extracted from Salmonella enterica serotype Typhimurium and Mycobacterium avium subsp . paratuberculosis, and subjected to four enzymatic treatments prior to NASBA . These enzymatic treatments were DNase, RNase, S1 nuclease, and RNase/S1 nuclease . The results obtained were different for the two bacteria . With S . enterica serotype Typhimurium, RNase and RNase/S1 nuclease abolished the NASBA signal, as expected . But with M . avium subsp . paratuberculosis RNase, S1 nuclease, and RNase/S1 nuclease had no effect on the NASBA signal, whereas DNase treatment abolished it . This indicates that in the latter bacterium, NASBA can detect DNA, and demonstrates the necessity of verifying the nucleic acid origin of a NASBA signal if detection of RNA is objective.

J Food Prot, 2004 Jul, 67(7), 1497 - 500
Survival of Escherichia coli O157:H7, Salmonella enteritidis, Staphylococcus aureus, and Listeria monocytogenes in Kimchi; Inatsu Y et al.; The survival of gram-positive and gram-negative foodborne pathogens in both commercial and laboratory-prepared kimchi (a traditional fermented food widely consumed in Japan) was investigated . It was found that Escherichia coli O157:H7, Salmonella Enteritidis, Staphylococcus aureus, and Listeria monocytogenes could survive in both commercial and laboratory-prepared kimchi inoculated with these pathogens and incubated at 10 degrees C for 7 days . However, when incubation was prolonged, the S . aureus level decreased rapidly from the initial inoculum level to the minimum detectable level within 12 days, whereas Salmonella Enteritidis and L . monocytogenes took 16 days to reach similar levels in commercial kimchi . On the other hand, E . coli O157:H7 remained at high levels throughout the incubation period . For laboratory-prepared kimchi, the S . aureus level decreased rapidly from the initial inoculum level to the minimum detectable level within 12 days, and L . monocytogenes took 20 days to reach a similar level . E . coli O157:H7 and Salmonella Enteritidis remained at high levels throughout the incubation period . The results of this study suggest that the contamination of kimchi with E . coli O157:H7, Salmonella Enteritidis, S . aureus, or L . monocytogenes at any stage of production or marketing could pose a potential risk.

J Food Prot, 2004 Jul, 67(7), 1489 - 93
Effect of short-term lairage on the prevalence of Salmonella enterica in cull sows; Larsen ST et al.; This study was designed to compare Salmonella enterica prevalence in sows held in a holding pen at the abattoir for approximately 2 h (hold sows) with sows slaughtered immediately after transport to the abattoir (no-hold sows) . Cull sows (n = 160) were sampled from four sampling periods over 8 weeks (February to March 2002) at the abattoir . Sows originated from an integrated swine farm and were sent to a live-hog market and then to the slaughter facility . Before testing, sows entered the abattoir pen and four 100-cm2 four-ply gauze squares were placed randomly on the pen floor for S . enterica culture . Sows were alternatively assigned to the hold or no-hold group . Samples collected from sows during slaughter were ileocecal lymph node, cecal contents, transverse colon contents, subiliac lymph node, sponge swabs of the left and right carcass section (300 cm2), and chopped meat . Overall, S . enterica was isolated from 44% (35 of 80) of the no-hold sows, which was significantly less (P < 0.05) than 59% (47 of 80) of the held sows . Also, no-hold sows had a lower cecal content prevalence (39%, 31 of 80) compared with that (55%, 44 of 80) of held sows (P < 0.05) . S . enterica serovars isolated from no-hold sows were Brandenburg (n = 16), Derby (n = 12), Hadar (n = 8), Infantis (n = 6), Johannesburg (n = 3), 6,7:z10-monophasic (n = 3), and Typhimurium (n = 1) . S . enterica serovars isolated from held sows (n = 61 isolates) were Derby (n = 19), 6,7: z10-monophasic (n = 15), Brandenburg (n = 10), Infantis (n = 6), Hadar (n = 5), Johannesburg (n = 4), and Tennessee (n = 2) . Serovars recovered from the pen were Reading (n = 6), Derby (n = 4), Uganda (n = 2), and Manhattan (n = 2) . Results of this study suggest that holding pens contribute to increased S . enterica carriage in cull sows . Abattoir holding pens might be an important control point for S . enterica in the ground pork production chain.

J Food Prot, 2004 Jul, 67(7), 1484 - 8
Acute infection of swine by various Salmonella serovars; Loynachan AT et al.; The objective of this study was to evaluate the ability of various serovars of Salmonella enterica subsp . enterica to infect alimentary and nonalimentary tissues of swine within 3 h of inoculation . Fourteen wild-type S . enterica serovars (4,12:imonophasic, 6,7 nonmotile, Agona, Brandenburg, Bredeney, Derby, Heidelberg, Infantis, Muenchen, Thompson, Typhimurium, Typhimurium variant Copenhagen, untypeable, and Worthington), two known virulent S . enterica serovars (Choleraesuis strain SC-38 and Typhimurium strain chi4232), and two avirulent S . enterica Choleraesuis vaccine strains (Argus and SC-54) were inoculated intranasally (approximately 5 x 10(9) cells) into swine (four animals per Salmonella isolate) . Three hours after inoculation, animals were euthanized, and both alimentary tissues (tonsil, colon contents, and cecum contents) and nonalimentary tissues (mandibular lymph node, thymus, lung, liver, spleen, ileocecal lymph node, and blood) were collected for Salmonella isolation . All Salmonella serovars evaluated except Salmonella Choleraesuis SC-54 acutely infected both alimentary and nonalimentary tissues . These results indicate that Salmonella isolates commonly found in swine are capable of acutely infecting both alimentary and nonalimentary tissues in a time frame consistent with that in which animals are transported and held in lairage prior to slaughter.

J Food Prot, 2004 Jul, 67(7), 1480 - 3
Critical control points for monitoring salmonellae reduction in thai commercial frozen broiler processing; Vadhanasin S et al.; Since 1998, pathogen reduction regulations for poultry have been enforced through the Food Safety and Inspection Service of the U.S . Department of Agriculture and through hazard analysis critical control point evaluation . This enforcement has focused attention on pathogen control and sanitation in the United States and in other countries, including Thailand . The objective of this study was to evaluate reduction in salmonellae achieved by Thai commercial exporters of frozen broiler chickens . A total of 188 broiler samples and 56 water overflows from two chillers were collected from nine processing lines of frozen broiler exporters at four identified critical control points (CCPs): CCP1, washing; CCP2, chilling; CCP3, deboning; and CCP4, packing . Samples were screened for salmonellae by enzyme-linked immunosorbent assay, and bacterial identification was confirmed through biochemical and serological patterns . The overall prevalence of Salmonella was 24.6% (60 of 244 samples), with 12 serovars identified . Salmonella Albany was predominant (33.3%, 20 of 60 samples) . Salmonella prevalence was 20.0% (6 of 30 samples) prior to CCP1 and was 12.5% (4 of 32), 22.7% (15 of 66), 33.3% (10 of 30), and 23.3% (7 of 30) after CCP1, CCP2, CCP3, and CCP4, respectively . The critical limit was 20% positive samples, and three CCPs failed to meet standards . Three corrective interventions were used at CCP2: 30 mg/liter hydrogen peroxide, 0.5% peracetic acid, and 125 mg/liter ozone . After these interventions, 65 broiler samples were collected for analysis of Salmonella prevalence . Results were compared with those obtained after chlorine was applied individually as a control . The Salmonella prevalences after intervention treatments were 16.0% (4 of 25), 5.0% (1 of 20), and 15.0% (3 of 20) after hydrogen peroxide, peracetic acid, and ozone treatments, respectively . All values were below the 20% critical limit, and the application of 0.5% peracetic acid produced significantly lower prevalences (P < 0.05) . Repeated sampling after 1 to 4 months indicated that sanitation at these three plants was inconsistent (P < 0.05).

J Food Prot, 2004 Jul, 67(7), 1444 - 50
Prevalence of high-risk egg-preparation practices in restaurants that prepare breakfast egg entrées: an EHS-Net study; Lee R et al.; Salmonella enterica serotype Enteritidis (SE) is a common cause of foodborne illness in the United States . Foods prepared with raw shell eggs have often been associated with SE outbreaks . The federal government published the Egg Safety Action Plan in December 1999 that called for reduction of egg-preparation practices that may contribute to the survival and proliferation of SE . In seven states, an interview and brief site evaluation of 153 restaurants that prepare eggs during all hours of operation was conducted by the Environmental Health Specialists Network to determine the prevalence of such practices . Fifty-four percent (83 of 153) of restaurants pooled raw shell eggs not intended for immediate service . These pooled eggs were held a median of 4 h for scrambled eggs, 5.5 h for omelets, and 6 h for pancakes and French toast . Nearly 26% (39 of 152) of restaurants reported storing eggs at room temperature, and 5% (7 of 152) stored eggs on ice or in cold-water baths before cooking . Generally, eggs were cooked to 72 to 83 degrees C, which is above the recommended final cook temperature of 63 to 68 degrees C . Employees reported sanitizing utensils used to prepare eggs less than once every 4 h in 42% (57 of 136) of restaurants . Several areas were identified in which further emphasis might reduce egg-associated SE infections in accordance with Healthy People 2010 goals.

J Food Prot, 2004 Jul, 67(7), 1433 - 7
Microbiological quality of ground beef from conventionally-reared cattle and "raised without antibiotics" label claims; LeJeune JT et al.; The contamination of the food supply with pathogens and antimicrobial-resistant bacteria has emerged as an important health concern . We compared the microbiological quality of 77 samples of ground beef from conventionally raised cattle with 73 samples of ground beef from cattle raised without antimicrobial agents . Contamination with coliforms (1.7 log CFU/g) and Escherichia coli (0.51 log CFU/g) and Shiga toxin 2-producing E . coli (6% prevalence) was similar in both sample groups . Neither Salmonella . E . coli O157, nor vancomycin-resistant enterococci were isolated from any sample . Prevalence of E . coli resistant to ampicillin (39%), amoxicillin/clavulanic acid (23%), ceftriaxone (5%), tetracycline (19%), streptomycin (19%), kanamycin (11%), sulfamethoxazole/trimethoprim (2%), and gentamicin (1%) was similar in both groups . E . coli resistant to ciprofloxacin was not identified . Resistance to ceftiofur and chloramphenicol was more prevalent in beef from conventionally raised cattle at 18 and 30%, respectively, compared to 5 and 12% prevalence in beef from cattle raised without antimicrobial agents . These results do not correlate with the frequency of subtherapeutic use of these two antibiotics in beef production . Other factors in addition to, or in lieu of, the subtherapeutic use of specific antimicrobial agents in the preharvest stages of beef production may contribute significantly to the occurrence of antimicrobial-resistant bacteria in ground beef.

J Food Prot, 2004 Jul, 67(7), 1403 - 7
Effect of sodium lactate on thermal inactivation of Listeria monocytogenes and Salmonella in ground chicken thigh and leg meat; Murphy RY et al.; The effect of sodium lactate on thermal inactivation D- and z-values of Listeria monocytogenes and Salmonella was determined for chicken thigh and leg meat . At 55 to 70 degrees C, the D-value of L . monocytogenes in ground chicken thigh and leg meat with the addition of 4.8% sodium lactate (4.8 g sodium lactate per 100 g of meat) was 53 to 75% higher than that in the meat without sodium lactate . No significant difference was found for the D-values of Salmonella at 55 to 70 degrees C between the meat with and that without sodium lactate (4.8% . wt/wt) . The z-values of both L . monocytogenes and Salmonella were not affected by sodium lactate (4.8%) . The results from this study are useful for predicting thermal process lethality of L . montocytogenes and Salmonella in formulated chicken thigh and leg meat products.

J Food Prot, 2004 Jul, 67(7), 1394 - 402
Thermal process validation for Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in ground turkey and beef products; Murphy RY et al.; At 55 to 70 degrees C, thermal inactivation D-values for Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes were 19.05 to 0.038, 43.10 to 0.096, and 33.11 to 0.12 min, respectively, in ground turkey and 21.55 to 0.055, 37.04 to 0.066, and 36.90 to 0.063 min, respectively, in ground beef . The z-values were 5.73, 5.54, and 6.13 degrees C, respectively, in ground turkey and 5.43, 5.74, and 6.01 degrees C, respectively, in ground beef . In both ground turkey and beef, significant (P < 0.05) differences were found in the D-values between E . coli O157:H7 and Salmonella or between E . coli O157:H7 and L . monocytogenes . At 65 to 70 degrees C, D-values for E . coli O157:H7, Salmonella, and L . monocytogenes were also significantly (P < 0.05) different between turkey and beef . The obtained D- and z-values were used in predicting process lethality of the pathogens in ground turkey and beef patties cooked in an air impingement oven and confirmed by inoculation studies for a 7-log (CFU/g) reduction of E . coli O157:H7, Salmonella, and L . monocytogenes.

J Food Prot, 2004 Jul, 67(7), 1384 - 8
The association between cleaning and disinfection of lairage pens and the prevalence of Salmonella enterica in swine at harvest; Schmidt PL et al.; A series of four field trials were conducted to evaluate the ability of a cleaning and disinfection procedure in swine lairage pens to reduce the prevalence of Salmonella enterica in slaughtered pigs . A cleaning and disinfection procedure was applied to lairage pens at a large Midwest abattoir . Each trial consisted of a cleaned (alkaline chloride detergent) and disinfected (H2O2 plus peracetic acid sanitizer) pen (treated) and a control pen, each holding 90 to 95 pigs for 2 to 3 h before slaughter . Ileocecal lymph nodes, cecal contents, and rectal contents were collected from 45 pigs from each study pen at harvest and cultured for S . enterica . In all trials, cleaning and disinfection reduced the prevalence of S . enterica-positive floor swabs in the treated pen (P < 0.05) . However, the postharvest prevalence of S . enterica-positive pigs varied between trials . In trial 1, there was no significant difference in the prevalence of S . enterica in pigs between treatment and control groups . In trials 2 and 3, the prevalence of S . enterica was higher in pigs from treated pens versus pigs from control pens (91% versus 40%, P < 0.0001, and 91% versus 24%, P < 0.0001, respectively) . In trial 4, the prevalence of S . enterica was lower in pigs from treated pens compared with pigs from control pens (5% versus 42%, P < 0.0001) . This study indicates that cleaning and disinfection effectively reduces the amount of culturable S . enterica in lairage pens, but the ability of cleaned and disinfected pens to reduce the prevalence of S . enterica in market-weight pigs remains inconclusive.

J Food Prot, 2004 Jul, 67(7), 1359 - 64
Attachment of Salmonella Poona to cantaloupe rind and stem scar tissues as affected by temperature of fruit and inoculum; Richards GM et al.; A negative temperature differential between fruits or vegetables and the water in which they are immersed theoretically enhances infiltration of water and any microorganisms it might contain into tissues . The effect of temperature differentials between cantaloupes and wash water, each at 4 and 30 degrees C, on changes in cantaloupe weight and populations of Salmonella enterica Poona recovered from rinds and stem scar tissues of Eastern and Western (shipper) types of cantaloupes was assessed . The percent weight increase in Western cantaloupes was significantly greater (P < or = 0.05) than that in Eastern cantaloupes for all cantaloupe and inoculum temperature combinations . Salmonella Poona attachment to or infiltration of Eastern but not Western cantaloupe rind is enhanced when the fruit is at 4 degrees C, compared with 30 degrees C, regardless of the temperature of the immersion suspension . The number of Salmonella Poona cells recovered from rind tissue of Western cantaloupes at 30 degrees C immersed in inoculum at 30 degrees C was significantly less (P < or = 0.05) than that recovered from rind tissues of cantaloupes at 4 or 30 degrees C that were immersed in inoculum at 4 degrees C . Salmonella Poona in immersion water can adhere to or infiltrate surface tissues of cantaloupes . The populations of Salmonella Poona recovered from stem scar tissues of Eastern and Western types of cantaloupes were not significantly (P > 0.05) affected by cantaloupe and inoculum temperature combinations . Populations of cells adhering to or infiltrating various cantaloupe tissues is not dictated entirely by temperature differentials between fruits and immersion suspensions: rather, it also apparently is influenced by structures unique to surface tissues.

J Food Prot, 2004 Jul, 67(7), 1344 - 52
Inactivation of Salmonella during drying and storage of Roma tomatoes exposed to predrying treatments including peeling, blanching, and dipping in organic acid solutions; Yoon Y et al.; The objective of this study was to evaluate the influence of predrying treatments, i.e., peeling, blanching prior to inoculation, and dipping in organic acid solutions, on inactivation of Salmonella during drying (60 degrees C for 14 h) and aerobic storage (25 degrees C for 28 days) of inoculated (five-strain composite, 7.1 to 7.4 log CFU/g) Roma tomato halves . Four predrying treatments groups were established . One group received no treatment (C) . In the other three groups, unpeeled-unblanched, unpeeled-blanched (steam blanched at 88 degrees C for 3 min), peeled-unblanched, and peeled-blanched tomato halves were immersed for 10 min in water (W), ascorbic acid solution (AA; 3.40%, pH 2.48), or citric acid solution (CA; 0.21%, pH 2.51) . Appropriate dilutions of homogenized tomato samples were spread plated on tryptic soy agar with 0.1% pyruvate and XLT4 agar for bacterial enumeration during drying and storage . Ten minutes of immersion in W, AA, or CA reduced bacterial populations by 0.7 to 1.6 log CFU/g . After 14 h of dehydration, total log reductions in the populations of bacteria were 3.2 to 4.5 (C), 3.7 to 4.9 (W), > 5.6 to > 6.1 (AA), and 4.5 to 5.5 (CA) log CFU/g, depending on type of agar used and condition of tomato samples . During drying and storage, the order of pathogen inactivation for predrying dipping treatments was AA > CA > W > C, with AA and CA rendering bacterial populations below detectable levels ( < 1.3 log CFU/g) prior to storage and between 7 and 14 days of storage, respectively . The results also indicated that peeling and blanching of tomatoes prior to inoculation may not necessarily affect destruction of Salmonella during the drying process . Use of predrying acid dipping treatments of tomatoes, especially in AA, may improve destruction of Salmonella during the dehydration process.

J Antimicrob Chemother, 2004 Sep, 54(3), 621 - 7 Epub 2004 Jul 21.
Effect of triclosan or a phenolic farm disinfectant on the selection of antibiotic-resistant Salmonella enterica; Randall LP et al.; OBJECTIVE: To determine the effect of growth of five strains of Salmonella enterica and their isogenic multiply antibiotic-resistant (MAR) derivatives with a phenolic farm disinfectant or triclosan (biocides) upon the frequency of mutation to resistance to antibiotics or cyclohexane . METHODS: Strains were grown in broth with or without the biocides and then spread on to agar containing ampicillin, ciprofloxacin or tetracycline each at 4x MIC or agar overlaid with cyclohexane . Incubation was for 24 and 48 h and the frequency of mutation to resistance was calculated for strains with and without prior growth with the biocides . MICs were determined and the presence of mutations in the acrR and marR regions was determined by sequencing and the presence of mutations in gyrA by light-cycler analysis, for a selection of the mutants that arose . RESULTS: The mean frequency of mutation to antibiotic or cyclohexane resistance was increased approximately 10- to 100-fold by prior growth with the phenolic disinfectant or triclosan . The increases were statistically significant for all antibiotics and cyclohexane following exposure to the phenolic disinfectant (P </= 0.013), and for ampicillin and cyclohexane following exposure to triclosan (P </= 0.009) . Mutants inhibited by >1 mg/L ciprofloxacin arose only from strains that were MAR . Reduced susceptibility to ciprofloxacin (at 4x MIC for parent strains) alone was associated with mutations in gyrA . MAR mutants did not contain mutations in the acrR or marR region . CONCLUSIONS: These data renew fears that the use of biocides may lead to an increased selective pressure towards antibiotic resistance.

FEMS Microbiol Lett, 2004 Aug 1, 237(1), 49 - 55
Fluorescence measurements of free {Mg2+} by use of mag-fura 2 in Salmonella enterica; Froschauer EM et al.; The Mg2+ fluorescent dye mag-fura 2, entrapped in cells or organelles, has frequently been used for dual excitation ratio-metric determinations of free ionic Mg2+ concentrations in eukaryotic, mostly mammalian cells . Here we report its successful application to measure free Mg2+ concentrations ({Mg2+}i) in Salmonella enterica cells . When kept in nominally Mg2+ free buffer (resting conditions), the {Mg2+}i of wild-type cells has been determined to be 0.9 mM . An increase in the external Mg2+ concentration ({Mg2+}e) resulted in a rapid increase of {Mg2+}i, saturating within a few seconds at about 1.5 mM with {Mg2+}e of 20 mM . In contrast, cells lacking the Mg2+ transport proteins CorA, MgtA, MgtB failed to show this rapid increase . Instead, their {Mg2+}i increased steadily over extended periods of time and saturated at concentrations below those of wild-type cells . Mg2+ uptake rates increased more than 15-fold when corA was overexpressed in these mutant cells . Uptake of Mg2+ into corA expressing cells was strongly stimulated by nigericin, which increased the membrane potential DeltaPsi at the expense of DeltapH, and drastically reduced by valinomycin, which decreased the membrane potential DeltaPsi . These results reveal mag-fura 2 as a useful indicator to measure steady-state {Mg2+}i values in resting bacterial cells and to determine Mg2+ uptake rates . They confirm the role of CorA as the major Mg2+ transport protein and reveal the membrane potential as driving force for Mg2+ uptake into S . enterica cells.

Expert Opin Biol Ther, 2004 Jul, 4(7), 1129 - 38
Taking a Toll on human disease: Toll-like receptor 4 agonists as vaccine adjuvants and monotherapeutic agents; Baldridge JR et al.; Toll-like receptor (TLR) agonists are being developed for use as vaccine adjuvants and as stand-alone immunomodulators because of their ability to stimulate innate and adaptive immune responses . Among the most thoroughly studied TLR agonists are the lipid A molecules that target the TLR4 complex . One promising candidate, monophosphoryl lipid A, which is a derivative of lipid A from Salmonella minnesota, has proven to be safe and effective as a vaccine adjuvant in > 120,000 human doses . A new class of synthetic lipid A mimetics, the aminoalkyl glucosaminide 4-phosphates (AGPs), have been engineered specifically to target human TLR4 and are showing promise as vaccine adjuvants and as monotherapeutic agents capable of eliciting nonspecific protection against a wide range of infectious pathogens . In this review, the authors provide an update of the preclinical and clinical experiences with the TLR4 agonists, MPL (Corixa Corporation) adjuvant and the AGPs.

Expert Opin Pharmacother, 2004 Aug, 5(8), 1737 - 43
Available options in the management of non-typhi Salmonella; Ruiz M et al.; Gastroenteritis, caused by Salmonella spp . is usually a self-limiting infection and does not require treatment . However, in some immunosuppressed patients (such as the newborn, the elderly, those with AIDS or neoplasms), there is a greater risk of developing a severe systemic infection, and in these cases, antibiotic treatment is recommended . Third-generation cephalosporins and fluoroquinolones are the most useful antibiotics in the treatment of these infections, although resistant strains are sometimes isolated . Therapeutic failures have been reported with fluoroquinolones in extra-intestinal infections caused by nalidixic acid resistant strains.

J Bacteriol, 2004 Aug, 186(15), 5078 - 86
Secretion and function of Salmonella SPI-2 effector SseF require its chaperone, SscB; Dai S et al.; Salmonella strains utilize a type III secretion system for their successful survival and replications inside host cells . SseF is one of the several effector proteins that are required for conferring this survival ability by altering the trafficking of the Salmonella-containing vacuoles . These effector proteins often require appropriate chaperones to maintain their stabilities inside the bacteria . These chaperones are also known to assist the subsequent secretion and translocation of their substrates . We report here that SscB acts as the chaperone for SseF, an effector for the Salmonella pathogenicity island 2 (SPI-2) . We found that the sscB gene is required for the formation of Salmonella sp.-induced continuous filaments in epithelial cells . Efficient Salmonella replication in macrophages requires SscB function . Intracellular and secretion levels of SseF are greatly reduced in an sscB mutant strain compared to the wild-type strain . A protein stability assay demonstrated that the half-life of SseF is significantly shortened in the absence of SscB . Transcriptional analysis of the sseF gene showed that the effect of SscB on the SseF level is not at the transcriptional level . A coprecipitation experiment indicated that SscB interacts with SseF . In summary, our results indicate that SscB is a chaperone for SPI-2 effector SseF to facilitate its secretion and function inside the host cells.

J Bacteriol, 2004 Aug, 186(15), 4931 - 9
Fibronectin binding to the Salmonella enterica serotype Typhimurium ShdA autotransporter protein is inhibited by a monoclonal antibody recognizing the A3 repeat; Kingsley RA et al.; ShdA is a large outer membrane protein of the autotransporter family whose passenger domain binds the extracellular matrix proteins fibronectin and collagen I, possibly by mimicking the host ligand heparin . The ShdA passenger domain consists of approximately 1,500 amino acid residues that can be divided into two regions based on features of the primary amino acid sequence: an N-terminal nonrepeat region followed by a repeat region composed of two types of imperfect direct amino acid repeats, called type A and type B . The repeat region bound bovine fibronectin with an affinity similar to that for the complete ShdA passenger domain, while the nonrepeat region exhibited comparatively low fibronectin-binding activity . A number of fusion proteins containing truncated fragments of the repeat region did not bind bovine fibronectin . However, binding of the passenger domain to fibronectin was inhibited in the presence of immune serum raised to one truncated fragment of the repeat region that contained repeats A2, B8, A3, and B9 . Furthermore, a monoclonal antibody that specifically recognized an epitope in a recombinant protein containing the A3 repeat inhibited binding of ShdA to fibronectin.

Biometals, 2004 Aug, 17(4), 471 - 81
The structure of salmochelins: C-glucosylated enterobactins of Salmonella enterica; Bister B et al.; Salmochelins represent novel carbohydrate containing catecholate siderophores, which are excreted by Salmonella enterica and uropathogenic Escherichia coli strains under low-iron stress . While previous analytical data showed salmochelins to contain 2,3-dihydroxybenzoyl-L-serine and glucose, the molecular structure remained elusive . Structure elucidation with electrospray ionization-Fourier transform ion cyclotron resonance-mass spectrometry (ESI-FTICR-MS), GC-MS and 2D-NMR now revealed that salmochelins are enterobactin-related compounds, which are beta-C-glucosylated at the 5-position of a 2,3-dihydroxybenzoyl residue . The key compound salmochelin S4 is a twofold beta-C-glucosylated enterobactin analogue . Comparison of partial structures of salmochelin with a C-glycosylated compound previously characterized by another group strongly suggest that salmochelins represent the long sought compounds termed Salmonella resistance factors (SRF) or pacifarins . Transformation of iro-genes into enterobactin-producing E . coli K12 confers the ability to produce salmochelins . A detailed analysis proved iroB to be the sole gene with glycosyltransferase activity necessary for salmochelin production . Salmochelins compared to enterobactin are the better siderophores in the presence of serum albumin . This may indicate for salmochelins a considerably more important role for pathogenic processes in certain Escherichia coli and Salmonella infections than formerly assigned to enterobactin . This conclusion is supported by the location of the iro genes on pathogenicity islands of uropathogenic E . coli strains.

Microbiology, 2004 Jul, 150(Pt 7), 2153 - 9
Structure-function relationships of UMP kinases from pyrH mutants of Gram-negative bacteria; Sakamoto H et al.; Bacterial uridine monophosphate (UMP) kinases are essential enzymes encoded by pyrH genes, and conditional-lethal or other pyrH mutants were analysed with respect to structure-function relationships . A set of thermosensitive pyrH mutants from Escherichia coli was generated and studied, along with already described pyrH mutants from Salmonella enterica serovar Typhimurium . It is shown that Arg-11 and Gly-232 are key residues for thermodynamic stability of the enzyme, and that Asp-201 is important for both catalysis and allosteric regulation . A comparison of the amino acid sequence of UMP kinases from several prokaryotes showed that these were conserved residues . Discussion on the enzyme activity level in relation to bacterial viability is also presented.

Microbiology, 2004 Jul, 150(Pt 7), 2055 - 68
The SPI2-encoded SseA chaperone has discrete domains required for SseB stabilization and export, and binds within the C-terminus of SseB and SseD; Zurawski DV et al.; SseA, a key Salmonella virulence determinant, is a small, basic pI protein encoded within the Salmonella pathogenicity island 2 and serves as a type III secretion system chaperone for SseB and SseD . Both SseA partners are subunits of the surface-localized translocon module that delivers effectors into the host cell; SseB is predicted to compose the translocon sheath and SseD is a putative translocon pore subunit . In this study, SseA molecular interactions with its partners were characterized further . Yeast two-hybrid screens indicate that SseA binding requires a C-terminal domain within both partners . An additional central domain within SseD was found to influence binding . The SseA-binding region within SseB was found to encompass a predicted amphipathic helix of a type participating in coiled-coil interactions that are implicated in the assembly of translocon sheaths . Deletions that impinge upon this putative coiled-coiled domain prevent SseA binding, suggesting that SseA occupies a portion of the coiled-coil . SseA occupancy of this motif is envisioned to be sufficient to prevent premature SseB self-association inside bacteria . Domain mapping on the chaperone was also performed . A deletion of the SseA N-terminus, or site-directed mutations within this region, allowed stabilization of SseB, but its export was disrupted . Therefore, the N-terminus of SseA provides a function that is essential for SseB export, but dispensable for partner binding and stabilization.

Microbiology, 2004 Jul, 150(Pt 7), 2037 - 53
A global role for Fis in the transcriptional control of metabolism and type III secretion in Salmonella enterica serovar Typhimurium; Kelly A et al.; Fis is a key DNA-binding protein involved in nucleoid organization and modulation of many DNA transactions, including transcription in enteric bacteria . The regulon of genes whose expression is influenced by Fis in Salmonella enterica serovar Typhimurium (S . typhimurium) has been defined by DNA microarray analysis . These data suggest that Fis plays a central role in coordinating the expression of both metabolic and type III secretion factors . The genes that were most strongly up-regulated by Fis were those involved in virulence and located in the pathogenicity islands SPI-1, SPI-2, SPI-3 and SPI-5 . Similarly, motility and flagellar genes required Fis for full expression . This was shown to be a direct effect as purified Fis protein bound to the promoter regions of representative flagella and SPI-2 genes . Genes contributing to aspects of metabolism known to assist the bacterium during survival in the mammalian gut were also Fis-regulated, usually negatively . This category included components of metabolic pathways for propanediol utilization, biotin synthesis, vitamin B(12) transport, fatty acids and acetate metabolism, as well as genes for the glyoxylate bypass of the tricarboxylic acid cycle . Genes found to be positively regulated by Fis included those for ethanolamine utilization . The data reported reveal the central role played by Fis in coordinating the expression of both housekeeping and virulence factors required by S . typhimurium during life in the gut lumen or during systemic infection of host cells.

Microb Drug Resist, 2004 Summer, 10(2), 146 - 53
Reduced susceptibility to ciprofloxacin and gyra gene mutation in North Indian strains of Salmonella enterica serotype Typhi and serotype Paratyphi A; Renuka K et al.; The emergence of reduced susceptibility to ciprofloxacin among Salmonella enterica serotype Typhi and serotype Paratyphi A leading to clinical failure of treatment poses a great therapeutic challenge . The mechanism of fluoroquinolone resistance in clinical isolates of S . Typhi and S . Paratyphi A is not very well documented . The present study was carried out with the objective of molecular characterization of reduced quinolone susceptibility amongst the strains of S . Typhi and S . Paratyphi A isolated from the patients with enteric fever during January, 2000, to April, 2003, in a North Indian hospital . A total of 422 culture-positive cases of enteric fever were reported to the hospital during the period of study, of which S . Typhi was isolated from 350 cases and S . Paratyphi A from 72 cases . The antimicrobial susceptibility of these strains was determined by disk diffusion and agar dilution method according to NCCLS guidelines, and E-test method . A total of 140 randomly selected strains, isolated during the years 1993-1999, that were available from the laboratory stocks were also studied to compare with the present strains . To study the quinolone susceptibility, the strains were divided into nalidixic acid sensitive (NAS), nalidixic acid intermediate resistant, (NAI) and nalidixic acid resistant (NAR) on the basis of susceptibility to nalidixic acid . Clinical history was available from 174 patients, of which 93 needed hospitalization due to severe disease . Of these, 82 patients were infected with NAR strains and 22 patients had a documented evidence of clinical failure to ciprofloxacin therapy . The patients infected with NAR strains were younger and had a significantly longer duration of fever (p value < 0.05) than those infected with NAS strains . It was observed that the proportion of NAR strains increased gradually over the years . These strains had a significantly higher range of MIC of ciprofloxacin (0.023-1.0 microg/ml) as compared to the NAS strains (0.002-0.125 microg/ml) (p value < 0.05) . The sequencing of quinolone resistance determining region (QRDR) of the gyrA gene showed the presence of mutation at either Ser 83 or at Asp 87 in all the NAR and NAI strains . None of the NAS strains had a mutation, suggesting that the gyrA gene mutation is sufficient to confer resistance to nalidixic acid and reduced susceptibility to ciprofloxacin . This mutation, although phenotypically expressed as decreased susceptibility to ciprofloxacin, goes undetected by the disk diffusion method using the present NCCLS guidelines . Hence, it can increase morbidity and mortality due to delay in appropriate antibiotic treatment.

Microb Drug Resist, 2004 Summer, 10(2), 83 - 91
Characterization and localization of drug resistance determinants in multidrug-resistant, integron-carrying Salmonella enterica serotype Typhimurium strains; Guerra B et al.; The genetic background of the antimicrobial resistance of 10 selected multiresistant Salmonella serotype Typhimurium (S . Typhimurium) strains (including the emerging monophasic variant {4,5,12:i:- }) was investigated . All strains shared class 1 integrons (with seven types of variable regions) and belonged to different lineages (L1-L6) according to their phage types, DNA polymorphisms by XbaI-pulsed-field gel electrophoresis (PFGE), integrons, and/or resistance patterns . The strains were screened for the presence and localization (chromosomal or plasmid) of 32 DNA sequences representing integron-, Tn21-like transposon-, resistance-, and virulence-plasmid genes . Strains belonging to lineage L1 (definitive phage type DT104) carried the 90-kb Salmonella virulence plasmid together with the complete or partial chromosomally located Salmonella Genomic Island 1 (SGI1) . All strains belonging to the other five lineages carried their resistance determinants on various resistance plasmids . Two of these strains showed complex plasmid profiles, which included a 95 kb virulence plasmid together with two or four resistance plasmids . Two strains carried a resistance plasmid that lacked the virulence-plasmid-encoding sequences . The remaining two strains carried two different hybrid virulence-resistance plasmids . Twenty-three of the DNA sequences could be assigned to distinct XbaI genomic restriction patterns (PFGE profiles) . In this way, the influence of the resistance and virulence plasmids on the PFGE profiles was determined, and several groups of resistance genes could be identified . The data obtained represent a useful epidemiological tool for tracing the emergence and distribution of multiresistant S . Typhimurium worldwide.

Indian J Exp Biol, 2003 Apr, 41(4), 360 - 2
In vitro efficacy of ciprofloxacin alone and in combination with amoxycillin against Salmonella typhi isolates; Mandal S et al.; Combined effect of ciprofloxacin (Ci) and amoxycillin (Ax) has been studied in vitro against 12 clinical isolates of S . typhi that showed Ci minimum inhibitory concentration (MIC) of > or =1 microg/ml . By agar dilution method, MIC values of Ax were 10-16 microg/ml for 11 isolates and 0.5 microg/ml for the remaining one isolate . The isolates, when treated with Ci and Ax in combination, showed fractional inhibitory concentration (FIC) of 0.004-0.256 microg/ml for Ci . FIC of Ax ranged from 6-10 microg/ml, except for a single isolate that showed Ax FIC of 0.25 microg/ml . Thus Ci was more efficacious in combination with Ax against S . typhi than Ci alone . The antibiotic combination exhibited an additive effect for all the isolates showing FIC index 0.504-0.832.

South Med J, 2004 Jun, 97(6), 583 - 7
Molecular epidemiologic surveillance of salmonellosis in Arkansas; Schutze GE et al.; OBJECTIVES: Salmonella serotype Newport and Salmonella serotype Typhimurium are the most commonly identified serotypes of Salmonella causing human disease in the state of Arkansas . The purpose of our study was to compare the results of standard and molecular epidemiologic methods of investigating human salmonellosis cases due to Salmonella serotype Newport and Salmonella serotype Typhimurium . METHODS: All isolates of Salmonella serotype Newport and Salmonella serotype Typhimurium collected and submitted to the Arkansas Department of Health between July 1, 1997 and June 30, 1998 were gathered and underwent pulsed-field gel electrophoresis (PFGE) . Patients from whom the isolates were collected were contacted and completed a questionnaire . RESULTS: There were 84 patients from whom Salmonella serotype Newport was isolated and 83 from whom Salmonella serotype Typhimurium was isolated during the study period . In the 124 patients (74%) who completed the questionnaire, Salmonella serotype Newport was more likely to be the infecting agent in younger, white, and pet-owning patients (P < 0.05) . The use of PFGE confirmed that approximately 20% of the organisms had genetic fingerprint patterns identical to those of at least one other individual in the state . One third of the patients from whom these isolates were obtained were linked by standard epidemiologic methods . CONCLUSIONS: The use of PFGE on our state's most common isolates provides additional confirmation that despite being linked by time of onset and location of residence, the majority of the human salmonellosis cases in our region are still sporadic . Low-level, intermittent transmission of these organisms through environmental contamination and contact with asymptomatically infected individuals would be likely vehicles of transmission in our state . Molecular techniques are important in surveillance systems that investigate human salmonellosis . Eighty-one percent of the Salmonella serotype Newport and 92% of the Salmonella serotype Typhimurium cases that appeared to be outbreak-related based upon time of onset and location were actually found not to be outbreak-related by PFGE . Using techniques such as PFGE will allow for more focused evaluations of potential outbreaks and will save the already limited financial and human resources that would otherwise be spent on investigations that are not warranted.

Environ Microbiol, 2004 Aug, 6(8), 868 - 71
Salmonella diversity associated with wild reptiles and amphibians in Spain; Briones V et al.; During the spring and summer of 2001, faeces from 166 wild reptiles (94 individuals) and amphibians (72 individuals) from 21 different species found in central Spain were examined for the presence of Salmonella . Thirty-nine reptiles (41.5%) yielded 48 Salmonella isolates, whereas all the amphibians examined were negative . Subspecies Salmonella enterica enterica (I) accounted for up to 50% of isolates . Fourteen isolates (29.2%) belonged to subspecies diarizonae (IIIb), six isolates (12.5%) to subspecies salamae (II), and four isolates (8.3%) to subspecies arizonae (IIIa) . Twenty-seven different serotypes were identified . Serotypes Anatum (12.5%), Herzliya (8.3%), Abony, 18:l,v:z, 9,12:z29:1,5 and 38:z10:z53 (6.2%/each) were the most frequently isolated . A high percentage (39.6%) of isolates belonged to serotypes previously associated with environmental sources . Also, 37.5% of isolates belonged to serotypes which had been related to human cases of salmonellosis . From these data, it is concluded that wild reptiles, but apparently not amphibians, may represent an important reservoir of Salmonella in nature and have potential implications for public health.

Res Microbiol, 2004 Jul-Aug, 155(6), 437 - 46
Improved methods for producing outer membrane vesicles in Gram-negative bacteria; Henry T et al.; Outer membrane vesicle formation occurs during Gram-negative bacterial growth . However, natural production of large amounts of outer membrane vesicles has only been described in a few bacterial genera . The purified vesicles of some bacterial pathogens have shown potential applications in vaccinology and in antibiotic therapy . This study focused on the development of a gene expression system able to induce production of large amounts of outer membrane vesicles . The Tol-Pal system of Escherichia coli, required to maintain outer membrane integrity, is composed of five cell envelope proteins, TolA, TolB, TolQ, TolR and Pal . Tol proteins are parasitized by filamentous bacteriophages and by colicins . The phage infection process and colicin import require, respectively, the N-terminal domain of the minor coat g3p protein and the translocation domain of colicins, with both domains interacting with Tol proteins . In this study, we show that the periplasmic production of either Tol, g3p or colicin domains was able to specifically destabilize the E . coli or Shigella flexneri cell envelope and to induce production of high amounts of vesicles . This technique was further found to work efficiently in Salmonella enterica serovar Typhimurium.

Arthritis Rheum, 2004 Jul, 50(7), 2255 - 63
Enhanced intracellular replication of Salmonella enteritidis in HLA-B27-expressing human monocytic cells: dependency on glutamic acid at position 45 in the B pocket of HLA-B27; Penttinen MA et al.; OBJECTIVE: To reveal the cause of the impaired elimination of Salmonella enteritidis in HLA-B27-transfected human monocytic cells and to study whether the B pocket of HLA-B27 contributes to these modulatory effects . METHODS: Stable U937 cell transfectants expressing HLA-A2, B27, or different forms of B27 with amino acid substitutions in the B pocket were prepared . Mock-transfected cells were prepared using the antibiotic resistance vector (pSV2neo) alone . Cells were differentiated, infected with S enteritidis, and the number of live intracellular S enteritidis organisms was determined using the colony-forming unit method . To visualize intracellular S enteritidis, the bacteria were transformed with green fluorescent protein (GFP), and studied by confocal microscopy . RESULTS: Cells expressing wild-type HLA-B27 were more permissive of intracellular replication of S enteritidis compared with mock-transfected or A2-transfected controls . Cells expressing B27 with an altered B pocket composition having either 6 amino acid substitutions (B27.A2B; substitutions H9F, T24A, E45M, I66K, C67V, and K70H) or a single substitution (B27.E45M) were no longer permissive of S enteritidis replication . In contrast, cells expressing B27 with the single substitution of F for H at position 9 (B27.H9F) retained their permissiveness . Studies using GFP-transformed S enteritidis confirmed that the increase in the amount of intracellular bacteria in B27-expressing cells was due to replication of the bacteria . CONCLUSION: Our data indicate that HLA-B27 expression modulates the host-microbe interaction that results in an impaired capacity of monocytes to resist intracellular replication of S enteritidis . The phenotype is dependent on glutamic acid at position 45 in the B pocket and, thus, may be due to properties of the B27 heavy chain that are related to this residue . The ability of HLA-B27 to confer susceptibility to Salmonella-triggered reactive arthritis may occur, at least in part, through these modulatory effects.

J Appl Microbiol, 1998 Jan, 84(1), 138 - 42
Inactivation of Salmonella typhi by high levels of volatile fatty acids during anaerobic digestion; Kunte DP et al.; Survival of Salmonella typhi was investigated in an anaerobic digester for cattle dung with volatile fatty acid (VFA) levels of 5000 mg l(-1) and pH 6.0 . The organism was added to the digester only once in the first experiment and daily in the other . Survival was monitored on alternate days . In the single dose experiment, the counts of Salm . typhi declined rapidly and the pathogen was completely eliminated within 12 d in the experimental digester (VFA ca 5000 mg l(-1) and pH 6.0), whereas 26 d were required in the control digester (VFA ca 100 mg l(-1) and pH 6.8) . T90 values for the experimental and control digesters were 2.44 d and 4.80 d, respectively . In the daily dose experiment, a four log reduction in the pathogen count was observed in the experimental digester, but only a two log reduction in the control digester at the end of the experimental period . The mean T90 values for the experimental and the control digester were 4.22 d and 18.63 d, respectively . In both the experiments, statistical analysis of the data showed significant differences in the survival pattern of Salm . typhi in the two digesters.

J Appl Microbiol, 1998 Jan, 84(1), 103 - 7
Pulsed-field electrophoretic fingerprinting of Salmonella indiana and its epidemiological applicability; Punia P et al.; Eight Xba I-generated pulsed-field profile (PFP) types and four subtypes within one of the most common PFP types have been identified in Salmonella indiana from patients, poultry and human food in England and Wales in the three-year period from January 1994 to December 1996 . Two PFP types have predominated, PFP X1 and PFP X2 . Although the PFP X1 type was identified throughout the study period, the PFP X2 type was not identified until late 1995, subsequently becoming the most common PFP type in humans in the first six months of 1996 with a significant distribution in elderly patients . It is concluded that PFGE can be used in support of epidemiological investigations for the subdivision of Salm . indiana . Furthermore, as both conditions and interpretation criteria can be easily standardized, it is suggested that for many salmonella serotypes, PFGE can provide the basis for a definitive scheme of genotypic subtyping suitable for epidemiological investigations at both a national and international level.

J Clin Microbiol, 2004 Jul, 42(7), 3359 - 62
Extended-spectrum-beta-lactamase (TEM-52)-producing strains of Salmonella enterica of various serotypes isolated in France; Weill FX et al.; From 2002 to 2003, four isolates of Salmonella enterica serotypes Typhimurium, Enteritidis, Blockley, and Panama, isolated in France from patients with gastroenteritis, were found to produce extended-spectrum beta-lactamase TEM-52 . The study showed the bla(TEM-52) gene to be located in a Tn3-like structure and carried by 100- or 32-kb conjugative plasmids.

J Clin Microbiol, 2004 Jul, 42(7), 3094 - 9
Endemic, epidemic clone of Salmonella enterica serovar typhi harboring a single multidrug-resistant plasmid in Vietnam between 1995 and 2002; Le TA et al.; Salmonella enterica serovar Typhi strains resistant to ampicillin, chloramphenicol, tetracyclines, streptomycin, and cotrimoxazole, isolated from sporadic cases and minor outbreaks in Vietnam between 1995 and 2002, were typed and compared . Plasmid fingerprinting, Vi bacteriophage typing, XbaI pulsed-field gel electrophoresis, and PstI ribotyping showed that endemic, epidemic multidrug-resistant typhoid fever was due, for at least 74.1% of the isolates, to one or two clones of serovar Typhi harboring a single resistance plasmid . PstI ribotyping was used as a basic technique to ensure that a serovar Typhi expansion was clonal.

J Antimicrob Chemother, 2004 Sep, 54(3), 688 - 91 Epub 2004 Jul 08.
Mutant prevention concentrations of ciprofloxacin and enrofloxacin for Salmonella enterica; Randall LP et al.; OBJECTIVES: To determine the mutant prevention concentrations (MPCs) of ciprofloxacin and enrofloxacin against four strains of Salmonella enterica serovar Enteritidis and four strains of S . Typhimurium including one fully susceptible, one multiply resistant (MAR), one GyrA mutant and one GyrA/MAR mutant . Further, to examine mutants arising after exposure to sub-MPC concentrations of the antibiotics for susceptibility to ciprofloxacin and enrofloxacin, and cyclohexane tolerance . METHODS: MICs were determined using the agar dilution method of the BSAC . The MPC was recorded as the lowest concentration of antibiotic to inhibit growth from an inoculum of 10(10) cfu . RESULTS: The MPCs and resulting MPC/MIC ratios of enrofloxacin were generally two- to four-fold higher than for ciprofloxacin . At 24 h for both antibiotics, MPCs were lowest for the fully susceptible strains (0.25-0.5 mg/L), similar for the MAR (1-4 mg/L) and GyrA (2-4 mg/L) mutants and highest for the GyrA/MAR mutants (1-8 mg/L) . MPC/MIC ratios at 24 h were 2-16 for all strains except those for the MAR strains without mutation in gyrA where the ratios were 8-64 . CONCLUSIONS: The ability to eradicate Salmonella in vivo depends on many factors such as antibiotic susceptibility of the strain, dose and route of administration . It is suggested that these MPC values will be useful when considering dosing strategies . In view of the high MPC/MIC ratio, MAR strains with wild-type gyrA, although susceptible to ciprofloxacin (MICs 0.06-0.13 mg/L), may give rise to treatment failures.

Lett Appl Microbiol, 2004, 39(2), 187 - 93
Comparison of primers for the detection of Salmonella enterica serovars using real-time PCR; Csordas AT et al.; AIMS: To evaluate the specificity and sensitivity of PCR primers for the detection of Salmonella enterica in a real-time PCR assay using pure cultures . METHODS AND RESULTS: Unenriched whole cells in sterile water were used as template for each PCR . SYBR Green dye was used for the nonspecific detection of dsDNA . The real-time PCR detection limits of five previously published primer sets used in conventional PCR applications were not below 3 x 10(3) CFU per reaction (rxn) . A new primer set, Sen, was designed, which detected Salm . enterica Newport down to 6 CFU rxn(-1) in one case, and gave an average detection limit of 35 CFU rxn(-1) over three separate runs . CONCLUSIONS: Primers originally designed for end-point PCR did not have adequate specificity or sensitivity compared with those specifically designed for real-time PCR . SIGNIFICANCE AND IMPACT OF THE STUDY: This study emphasizes the importance of evaluating real-time PCR primer sets in pure cultures prior to testing in field samples . This study will benefit other researchers in selecting an appropriate primer set for real-time PCR detection of Salm . enterica.

Appl Environ Microbiol, 2004 Jul, 70(7), 4030 - 4
Characterization of Salmonella enterica serovar typhimurium from marine environments in coastal waters of Galicia (Spain); Martinez-Urtaza J et al.; Twenty-three Salmonella enterica serovar Typhimurium isolates from marine environments were characterized by phage typing, pulsed-field gel electrophoresis (PFGE) analysis, plasmid analysis, and antibiotic resistance, and the distribution of the different types in the coastal waters were subsequently analyzed . Five phage types were identified among the isolates (PT41, PT135, PT99, DT104, and DT193) . PT135 isolates were exclusively detected during the winter months from 1998 to 2000, whereas DT104 and PT41 isolates were detected exclusively in the summer months from 2000 to 2002 . XbaI PFGE analysis revealed 9 PFGE types, and plasmid profiling identified 8 plasmid types (with 1 to 6 plasmids) among the isolates . Only three isolates presented multidrug resistance to antibiotics . Two DT104 isolates were resistant to 8 and 7 antibiotics (profiles ACCeFNaSSuT and ACeFNeSSuT), whereas a PT193 isolate presented resistance to 6 antibiotics (profile ACFSSu) . In addition, four PT41 isolates were resistant to a single antibiotic . The detection of multidrug-resistant phage types DT104 and DT193 in shellfish emphasizes the importance of monitoring the presence of Salmonella in routine surveillance of live bivalve molluscs.

Ann R Coll Surg Engl, 2004 Jul, 86(4), 272 - 4
Septic arthritis of the knee by Salmonella montevideo; Katsoulis E et al.; We describe a case of salmonella septic arthritis of the knee in a middle-aged woman with the following predisposing conditions: long-term corticosteroids and microscopic collagenous colitis . The patient presented with enteritis caused by the same strain 3 months before the arthritis . The first series of cultures were negative and the possibility of a chronic carriage of the disease was not suspected initially . The patient was treated with antibiotics and arthroscopic washouts; the corticosteroid treatment was maintained . There was a progressive clinical and microbiological improvement and the patient was discharged 3 weeks later . Salmonella montevideo is a rare form of salmonella and is known to be associated with tropical fishes, reptiles and imported species.

Biomedica, 2004 Mar, 24(1), 89 - 96
{Presence of Salmonella as a risk to public health in the Caribbean zone of Colombia}; Durango J et al.; Salmonella is frequently involved in diarrhoeal disease throughout the world and is disseminated mainly by food, polluted waters or infected food-handlers . In Colombia, the serotypes of Salmonella and their distribution in food have not been characterized . Therefore, the objective was to establish the epidemiology of Salmonella in the Caribbean zone . Six hundred thirty-six samples were obtained in fast food outlets located in city squares or markets of Barranquilla (n=245), Monteria (n=222), Sincelejo (n=87) and Cartagena (n=82) . Salmonella was isolated by the conventional methods recommended by the United States Food and Drug Administration . Briefly, 25 g of each sample was inoculated in 225 ml of broth . Twenty-four hours later, a 1 ml aliquot was inoculated onto selective media for Salmonella . Suspicious colonies were identified by conventional biochemical tests and confirmed by conventional serology for Salmonella detection . Forty-seven Salmonella serotypes were isolated from meat (40%), sausage (25%), cheese (13%), pig (13%), chicken (4.2%) and egg 'arepas' (4.2%) . The serologic characterization indicated the following serotypes: S . Anatum (26%), S . Newport (13%), S . Typhimurium (9%), S . Gaminara (9%) and S . Uganda (9%) . No statistically significant Salmonella isolations among 4 socioeconomic categories were observed (p=0.05) . However, differences were observed when rates were compared for Salmonella by food type for socioeconomic categories 1, 2 and 3 (p<0.05), categories 2 and 3 did not show differences between them (p>0.05).

Mutat Res, 2004 Jul 11, 561(1-2), 101 - 17
Mutagenicity of sediment and biomarkers of oxidative stress in fish from aquatic environments under the influence of tanneries; Tagliari KC et al.; The mutagenicity of interstitial water and organic extracts from the sediments in the Cadeia and Feitoria Rivers, RS, Brazil, were evaluated by Salmonella microsuspension bioassay using TA97a, TA98, TA100 and TA102 strains, in the absence and presence of S9 mix . At the contaminated site, the mutagenic responses for interstitial water, suggested the presence of frameshift and base pair substitution mutagens, including oxidative substances . Organic extracts presented direct or indicative mutagenesis to the TA97a, TA98 and TA100 strains . In general, an exogenous metabolic systems decreased the mutagenicity of the samples . High concentrations of total chromium found in the sediment and interstitial water as well as total mercury in the sediment of the contaminated site, when compared to the control area, may help explain the mutagenic results . The livers of Gymnogeophagus gymnogenys collected in this impacted area, compared to a non-polluted site, were analyzed for oxidative stress parameters . Compared to the controls, there was a significant increase in the activity of superoxide dismutase (SOD) at levels of substances reactive to thiobarbituric acid (TBARS), and in the chemiluminescence of hepatic cells in fish in the polluted area . The concentration of cytochromes P450 and b5 decreased drastically in the fish at the polluted site, while the catalase activity did not change . It was possible to correlate the biological changes in the fish with the presence of mutagenic compounds in sediment and interstitial water in this area.

J Mol Biol, 2004 Jul 23, 340(5), 1005 - 12
Identification of the protein acetyltransferase (Pat) enzyme that acetylates acetyl-CoA synthetase in Salmonella enterica; Starai VJ et al.; Post-translational modification of proteins is an efficient way cells use to control the activity of structural proteins, gene expression regulatory proteins, and enzymes . In eukaryotes, the Sir2-dependent system of protein acetylation/deacetylation controls a number of processes that affect cell longevity . Sir2 proteins have NAD(+)-dependent protein deacetylase activity and are found in all forms of life . Although the identity of the acetyltransferases that partner with Sir2 enzymes is known in eukaryotes, the identity of the prokaryotic acetyltransferases is not . We report the identification of the gene of Salmonella enterica serovar Typhimurium LT2 encoding the major protein acetyltransferase (Pat) enzyme that, in concert with the CobB sirtuin of this bacterium, regulates the activity of the central metabolic enzyme acetyl-coenzyme A synthetase (Acs) . The Pat enzyme uses acetyl-CoA as substrate to modify residue Lys609 of Acs . The Pat/CobB system of S.enterica should serve as the paradigm to further investigate the contributions of this system to the physiology of prokaryotes.

Arch Microbiol, 2004 Sep, 182(1), 37 - 43 Epub 2004 Jul 03.
Expression of cspH upon nutrient up-shift in Salmonella enterica serovar Typhimurium; Kim BH et al.; The gene cspH, which encodes one of the cold-shock proteins in Salmonella enterica serovar Typhimurium, has previously been reported to be induced during early exponential phase at 37 degrees C . In the present study, the expression of cspH upon nutrient up-shift at 37 degrees C was investigated and found to be affected by DNA gyrase and DNA-binding protein Fis . When cells at stationary phase were subcultured into a rich medium, the mRNA level of cspH increased dramatically prior to the first cell division . However, when the cells were treated with DNA gyrase inhibitors, cspH mRNA was not induced upon nutrient up-shift . The low level of DNA superhelical density at the cspH promoter in part affected the expression of cspH mRNA in vitro . In addition, a fis-deficient strain had a lower level of cspH mRNA than the wild-type upon nutrient up-shift . Finally, a cspH-lacZ construct, in which the putative binding region for Fis was deleted in the cspH promoter, expressed a low level of LacZ, in contrast to the native cspH-lacZ construct.

J Microbiol Methods, 2004 Aug, 58(2), 285 - 8
Evaluation of an automated immunomagnetic separation method for the rapid detection of Salmonella species in poultry environmental samples; Lynch MJ et al.; Automated immunomagnetic separation (AIMS), using Dynabeads anti-Salmonella (Dynal, Oslo), was evaluated for its ability to detect Salmonella spp . in poultry environmental samples in comparison with standard, culture-based method (Health Canada, Health Protection Branch, MFHPB-20) . AIMS was found to be more reliable in detecting Salmonella from artificially inoculated enrichment broths at low levels and exhibited a 15.5% higher sensitivity value than the culture method.

Dtsch Tierarztl Wochenschr, 2004 May, 111(5), 212 - 4
{Evaluation of the sampling plan for a Salmonella monitoring program for slaughter pigs}; Osterkorn K et al.; In the setting of the Salmonella monitoring programme of the Federal Republic of Germany the sampling plan does not take into account prevalences occuring in reality . Hence, in most farms the testing effort will increase . This particularly applies to pig farms up to 100 fatteners, for which the proportion of animals to be tested is too high . Besides, the threshold values determing the allocation to the three quality categories, less than 20%, 20-40%, and more than 40% Salmonella positive fatteners, are also chosen too high.

Indian J Exp Biol, 2004 Mar, 42(3), 303 - 13
Haemolysins of Salmonella, their role in pathogenesis and subtyping of Salmonella serovars; Singh BR et al.; Haemolysin patterns of 175 strains of different Salmonella enterica subspecies enterica serovars isolated from different animal sources and places were determined using 11 different blood agar media made with either non-washed horse/sheep erythrocytes or with washed erythrocytes of cattle, sheep, horse, goat, rabbit, guinea pig, and human A, O and B blood groups . Study on 47 strains belonging to 10 serovars of Salmonella from buffalo meat (buffen), 42 strains of 11 serovars from goat meat (chevon): 16 strains of Salmonella enterica serovar Paratyphi B and 25 of S . enterica serovar Paratyphi B var Java from fish, meat, meat products and clinical cases; 45 isolates of S . Abortusequi from aborted mares (18), fetal contents (21), aborted donkey mares (2) and 4 reference strains, revealed that all host restricted Salmonella namely, S . enterica serovar Gallinarum, S . enterica serovar Anatum, S . enterica serovar Abortusequi and S . enterica serovar Paratyphi B could be divided into different haemolysin types based on their inability to produce haemolysis on one or more types of blood agar, while strains of all zoonotic Salmonella serovars induced haemolysis on all the 9 types of blood agar made of washed erythrocytes . None of 175 Salmonella could produce hemolytic colonies on blood agar made of non-washed horse/ sheep erythrocytes . Haemolysin type I (lysing all types of washed erythrocytes) was the commonest one among all serovars except S . Abortusequi, none of which lysed horse erythrocytes . Salmonella enterica serovar Abortusequi having hemolytic activity against sheep erythrocytes were more invasive but had lesser ability to survive in sheep mononuclear cells than non-hemolytic strains . Multiplicity of haemolysins appeared significant epidemiological tool.

Reproduction, 2004 Jul, 128(1), 87 - 97
A 'minimum dose' of lipopolysaccharide required for implantation failure: assessment of its effect on the maternal reproductive organs and interleukin-1alpha expression in the mouse; Deb K et al.; Genital tract infections caused by gram-negative bacteria induce abortion and are one of the most common complications of human pregnancy . This study was carried out to decipher the mechanism of gram-negative bacterial lipopolysaccharide (LPS)-induced pregnancy loss, using a mouse (Park strain) model . Since many of the biological effects of LPS are mediated by interleukin (IL)-1alpha, the role of IL-1alpha in LPS-induced pregnancy loss was studied . Pregnant female animals were injected intra-peritoneally (i.p.) with different doses (1 to 50 microg) of LPS from Salmonella minnesota Re-595, on day 0.5 of pregnancy . We found that 250 microg/kg body weight (i.e . 5 microg/female mouse) of LPS when given on day 0.5 of pregnancy was the 'minimum dose' (MD) required to completely inhibit the implantation of the blastocyst in the mouse . The effect of this dose on the pathophysiology of the various reproductive organs (i.e . uterus, ectoplacental cones, developing fetus, ovaries etc.) was assessed on day 14 of pregnancy . The effects of this dose on the level and pattern of expression of the proinflammatory cytokine IL-1alpha in the maternal uterine horns and preimplantation stage embryos were studied by RT-PCR . A single dose (100 ng/mouse) of recombinant mouse IL-1alpha was given i.p . to pregnant females on day 1 of pregnancy to study its effect on implantation . Our results show that treatment of the pregnant animals with LPS may alter cell proliferation and induce leukocyte infiltration, degeneration of luminal glandular epithelium, and hyperplasia in the various reproductive organs, and may also alter both embryonic and uterine IL-1alpha expression . IL-1alpha administration also caused implantation failure similar to that of LPS . The observations suggest that the determined MD of LPS may alter the expression of developmentally important proinflammatory cytokines such as IL-1alpha, which could, in turn, inhibit the normal processes of blastocyst implantation . Therefore, it is proposed that the LPS-induced histopathological alterations in the various reproductive organs of pregnant animals could be mediated by IL-1alpha and this may be one of the causes of failure of blastocyst implantation in the mouse.

J Bacteriol, 2004 Jul, 186(14), 4694 - 704
Delineation of upstream signaling events in the salmonella pathogenicity island 2 transcriptional activation pathway; Kim CC et al.; Survival and replication in the intracellular environment are critical components of the ability of Salmonella enterica serovar Typhimurium to establish systemic infection in the murine host . Intracellular survival is mediated by a number of genetic loci, including Salmonella pathogenicity island 2 (SPI2) . SPI2 is a 40-kb locus encoding a type III secretion system that secretes effector molecules, which permits bacterial survival and replication in the intracellular environment of host cells . A two-component regulatory system, ssrAB, is also encoded in SPI2 and controls expression of the secretion system and effectors . While the environmental signals to which SPI2 responds in vivo are not known, activation of expression is dependent on OmpR and can be stimulated in vitro by chelation of cations or by a shift from rich to acidic minimal medium . In this work, we demonstrated that SPI2 activation is associated with OmpR in the phosphorylated form (OmpR-P) . Mutations in envZ and ackA-pta, which disrupted two distinct sources of OmpR phosphorylation, indicated that SPI2 activation by chelators or a shift from rich to acidic minimal medium is largely dependent on functional EnvZ . In contrast, the PhoPQ pathway is not required for SPI2 activation in the presence of OmpR-P . As in the case of in vitro stimulation, SPI2 expression in macrophages correlates with the presence of OmpR-P . Additionally, EnvZ, but not acetyl phosphate, is required for maximal expression of SPI2 in the intracellular environment, suggesting that the in vitro SPI2 activation pathway is the same as that used in vivo .

J Bacteriol, 2004 Jul, 186(14), 4605 - 12
The CorA Mg2+ transporter is a homotetramer; Warren MA et al.; CorA is a primary Mg2+ transporter for Bacteria and Archaea . The C-terminal domain of approximately 80 amino acids forms three transmembrane (TM) segments, which suggests that CorA is a homo-oligomer . A Cys residue was added to the cytoplasmic C terminus (C317) of Salmonella enterica serovar Typhimurium CorA with or without mutation of the single periplasmic Cys191 to Ser; each mutant retained function . Oxidation of the Cys191Ser Cys317 CorA gave a dimer . Oxidation of Cys317 CorA showed a dimer plus an additional band, apparently cross-linked via both Cys317 and C191 . To determine oligomer order, intact cells or purified membranes were treated with formaldehyde or carbon disulfide . Higher-molecular-mass bands formed, consistent with the presence of a tetramer . Cross-linking of the Bacillus subtilis CorA expressed in Salmonella serovar Typhimurium similarly indicated a tetramer . CorA periplasmic soluble domains from both Salmonella serovar Typhimurium and the archaeon Methanococcus jannaschii were purified and shown to retain structure . Formaldehyde treatment showed formation of a tetramer . Finally, previous mutagenesis of the CorA membrane domain identified six intramembrane residues forming an apparent pore that interacts with Mg2+ during transport . Each was mutated to Cys . In mutants carrying a single intramembrane Cys residue, spontaneous disulfide bond formation that was enhanced by oxidation with Cu(II)-1,10-phenanthroline was observed between monomers, indicating that these Mg2+-interacting residues within the membrane are very close to their cognate residue on another monomer . Thus, CorA appears to be a homotetramer with a TM segment of one monomer physically close to the same TM segment of another monomer .

J Bacteriol, 2004 Jul, 186(14), 4568 - 74
Transposition of the heat-stable toxin astA gene into a gifsy-2-related prophage of Salmonella enterica serovar Abortusovis; Bacciu D et al.; The horizontal transfer and acquisition of virulence genes via mobile genetic elements have been a major driving force in the evolution of Salmonella pathogenicity . Serovars of Salmonella enterica carry variable assortments of phage-encoded virulence genes, suggesting that temperate phages play a pivotal role in this process . Epidemic isolates of S . enterica serovar Typhimurium are consistently lysogenic for two lambdoid phages, Gifsy-1 and Gifsy-2, carrying known virulence genes . Other serovars of S . enterica, including serovars Dublin, Gallinarum, Enteritidis, and Hadar, carry distinct prophages with similarity to the Gifsy phages . In this study, we analyzed Gifsy-related loci from S . enterica serovar Abortusovis, a pathogen associated exclusively with ovine infection . A cryptic prophage, closely related to serovar Typhimurium phage Gifsy-2, was identified . This element, named Gifsy-2AO, was shown to contribute to serovar Abortusovis systemic infection in lambs . Sequence analysis of the prophage b region showed a large deletion which covers genes encoding phage tail fiber proteins and putative virulence factors, including type III secreted effector protein SseI (GtgB, SrfH) . This deletion was identified in most of the serovar Abortusovis isolates tested and might be dependent on the replicative transposition of an adjacent insertion sequence, IS1414, previously identified in pathogenic Escherichia coli strains . IS1414 encodes heat-stable toxin EAST1 (astA) and showed multiple genomic copies in isolates of serovar Abortusovis . To our knowledge, this is the first evidence of intergeneric transfer of virulence genes via insertion sequence elements in Salmonella . The acquisition of IS1414 (EAST1) and its frequent transposition within the chromosome might improve the fitness of serovar Abortusovis within its narrow ecological niche .

J Antimicrob Chemother, 2004 Aug, 54(2), 354 - 9 Epub 2004 Jul 01.
Characterization of a Salmonella enterica serovar Agona strain harbouring a class 1 integron containing novel OXA-type beta-lactamase (blaOXA-53) and 6'-N-aminoglycoside acetyltransferase genes {aac(6')-I30}; Mulvey MR et al.; OBJECTIVE: To characterize by molecular methods a multidrug-resistant Salmonella enterica serovar Agona (S . enterica Agona) isolated from a hospitalized patient in Rio de Janeiro, Brazil . METHODS: The S . enterica Agona strain was screened by PCR and DNA sequencing for TEM, SHV and CTX-M-type beta-lactamase genes, tet(A), (B), (C) and (D) tetracycline resistance genes, chloramphenicol resistance genes and class 1 integrons . Plasmid characterization was carried out by PCR and Southern hybridization analysis . PCR and PFGE were used to characterize nine other S . enterica Agona strains collected from hospitals in Rio de Janeiro . RESULTS: The study strain was found to harbour a 105 kb plasmid, which contained catA1, bla(TEM-1), a class 1 integron with two novel genes labelled bla(OXA-53) and aac(6')-I30, respectively, and an additional unidentified aminoglycoside resistance gene . A second 53 kb plasmid from the same strain contained tet(D) and bla(SHV-5) . OXA-53 was shown to provide reduced susceptibility to ceftazidime, and its activity was inhibited in the presence of clavulanic acid . PFGE analysis of the nine other S . enterica Agona strains revealed two clusters of related strains (78% similarity), and PCR analysis showed that all strains contained the novel integron . CONCLUSION: An S . enterica Agona strain was found to harbour three plasmid-encoded beta-lactamases, one (OXA-53) on a novel class 1 integron that also contains a new aminoglycoside resistance gene, aac(6')-I30 . The multidrug resistance plasmids appear to have disseminated to other city hospitals via other S . enterica Agona strains.

Pol J Vet Sci, 2004, 7(2), 109 - 12
Lipid peroxidation as the additional indicator of transport stress in broilers; Tokarzewski S et al.; Stressful conditions (transport, temperature fluctuations, infections and excessive crowding) lead to dysfunction of immunological mechanisms in birds . They influence the lipid balance what manifests itself through the increase of the malonodialdehyde (MDA) level, reacting with the 2-thiobarbituric acid (TBA), what is an indicator of lipid peroxidation . In the case of birds, the classical indicator of the stressful reaction is the heterophile/lymphocyte ratio (H/L), which changes depending on the stress intensity . The present study defined the influence of road transport on lipid peroxidation process as the additional indicator of stress in broilers . The investigation was conducted on 10 broilers Ross 308 (39 days old), which were transported on the distance of 70 km . The birds were clinically healthy, free of parasites and free of Salmonella spp . infection in the beginning of the experiment . The determination of the TBA-reactive substances (TBARS) in serum was conducted according to the method proposed by Ledwozyw et al . (1986) . The analysis of the results with a Student t-test showed the statistically significant difference (P < or = 0.05) in the TBA-reactive substances level before and directly after the birds transportation.

J Rheumatol, 2004 Jul, 31(7), 1340 - 3
Osteomyelitis in patients with systemic lupus erythematosus; Wu KC et al.; OBJECTIVE: To investigate the clinical profile of and the risk factors for osteomyelitis in patients with systemic lupus erythematosus (SLE) . METHODS: We reviewed 11 consecutive cases of patients with SLE who had also had osteomyelitis between 1981 and 2001 at a medical center in Taiwan, with special attention to predisposing factors, clinical features, laboratory values, and outcomes . RESULTS: The mean age at diagnosis of osteomyelitis was 34.5 +/- 22.0 years and the ratio of females to males was 9:2 . The typical initial manifestations were nonspecific focal pain (82%) and fever (64%) . The most commonly affected sites were the long bones (6 cases, 54%), followed by the vertebrae (4 cases, 36%) . Salmonella (5 cases, 45%) and Staphylococcus aureus (4 cases, 36%) were the major causative organisms . Interestingly, once long bones had become involved, 5 of 6 (83%) isolates proved to be Salmonella, and for vertebral osteomyelitis, 3 of 4 (75%) isolates proved to be S . aureus . Predisposing factors include an active status of SLE (SLEDAI score >/= 4, 100%), coexistent underlying systemic disease (91%), chronic renal disease (82%), and intensified immunosuppressive agent usage (82%) . Laboratory values either reflected an acute phase reaction that would be expected in an infection, such as a raised C-reactive protein (100%) and neutrophilia (55%), or reflected features consistent with active lupus disease . Four patients had longterm motor deficits and another patient died . Poor prognostic factors include delayed diagnosis, vertebral involvement, artificial implants in bones, and chronic carrier status . CONCLUSION: In patients with SLE who present with local osteoarticular pain, particularly those whose disease is active and who also have chronic renal disease and were taking intensified immunosuppressive agents, osteomyelitis must be considered seriously . Salmonella should be considered as a potential contributing pathogen for long bone osteomyelitis and S . aureus should be considered for cases of vertebral osteomyelitis when conducting empirical antimicrobial therapy . Early recognition and treatment is essential to avoid longterm sequelae or death.

Ann Clin Lab Sci, 2004 Spring, 34(2), 214 - 7
Case report: Bacteremia due to Salmonella enterica Serotype Montevideo producing plasmid-mediated AmpC beta-lactamase (DHA-1); Kim JY et al.; A Salmonella enterica Serotype Montevideo is described that harbors DHA-1, a plasmid-mediated AmpC beta-lactamase . The organism was isolated from blood and stool specimens of a 3-yr-old girl . The isolate was multi-drug resistant, including cefoxitin, gentamicin, piperacillin, cefuroxime, ceftazidime, and cefotaxime, and an antagonism was observed between cefoxitin and oxyiminocephalosporins . The resistance to ceftazidime and cefotaxime was transferred by conjugation to the recipient E . coli J53 . To our knowledge, this is the first description of Salmonella enterica Serotype Montevideo harboring DHA-1.

Ethiop Med J, 2003 Jul, 41(3), 257 - 66
The prevalence of Yersinia enterocolitica isolates in comparison to those of the commonly encountered enteropathogens causing diarrhoea among Ethiopian patients in Addis Ababa; Andualem B et al.; This cross-sectional study was designed to determine and describe the prevalence of diarrhoea caused by Yersinia enterocolitica isolates in comparison with the commonly encountered diarrhoeagenic Salmonella and Shigella among all age group out-patients of Addis Ababa, Ethiopia . Standardized bacteriological isolation and biochemical test techniques were used . Among the stool samples of 205 patients tested for bacteriological cultures, only 3 (1.5%) were positive for Yersinia enterocolitica, 22 (10.7%) for Salmonella and 12 (5.8%) for Shigella . In this study, Yersinia enterocolitica did not seem to be the main aetiological enteric pathogenic agent when compared with the well-studied diarrhoeacogenic bacteria agents like Salmonella and Shigella strains.

Folia Microbiol (Praha), 2004, 49(2), 199 - 202
In vitro effect of C2-C18 fatty acids on Salmonellas; Skrivanova E et al.; The susceptibility of Salmonella spp . to 15 fatty acids was determined in vitro in cultures grown on glucose . Antimicrobial activity was expressed as IC50 (a concentration at which only 50% of the initial glucose in cultures was utilized) . Caprylic acid was the only acid inhibiting glucose utilization . In cultures of S . enteritidis, S . infantis and S . typhimurium, IC50 of caprylic acid ranged from 0.75 to 1.17 mg/mL . A moderate adaptation effect was observed as these values increased 1.5-1.8 times when bacteria were subcultured 10 times in media containing a low concentration of caprylic acid (1/3 IC50) . No effect of calcium ions added in excess on antimicrobial activity of caprylic acid was observed . Incubation of salmonellas with caprylic acid (1 mg/mL; 30 min) at pH 5.2-5.3 led to a reduction in the concentration of viable cells below the detection limit; 2-6% of Salmonella cells survived at pH 6.3-6.6.

Mol Microbiol, 2004 Jul, 53(1), 229 - 41
PhoP-regulated Salmonella resistance to the antimicrobial peptides magainin 2 and polymyxin B; Shi Y et al.; In Salmonella enterica, the PhoP-PhoQ two-component system governs resistance to structurally different antimicrobial peptides including the alpha-helical magainin 2, the beta-sheet defensins and the cyclic lipopeptide polymyxin B . To identify the PhoP-regulated determinants mediating peptide resistance, we prepared a plasmid library from a phoP mutant, introduced it into a phoP mutant and selected for magainin-resistant clones . One of the clones harboured the PhoP-activated ugtL gene, deletion of which rendered Salmonella susceptible to magainin 2 and polymyxin B, but not defensin HNP-1 . We established that ugtL encodes an inner membrane protein that promotes the formation of monophosphorylated lipid A in the lipopolysaccharide . Inactivation of both ugtL and the regulatory gene pmrA, which controls lipid A modifications required for resistance to polymxyin B (but not to magainin 2) and is post-transcriptionally activated by the PhoP-PhoQ system, resulted in a strain that was as susceptible to polymyxin B as a phoP mutant . The most frequently recovered clone harboured the yqjA gene, which we show is PhoP regulated and required for resistance to magainin 2 but not to polymyxin B or defensin HNP-1 . Our results indicate that different PhoP-mediated modifications in lipid A are necessary for resistance to different antimicrobial peptides.

Avian Pathol, 2004 Jun, 33(3), 314 - 20
Effect of type 1 fimbriae of Salmonella enterica serotype Enteritidis on bacteraemia and reproductive tract infection in laying hens; De Buck J et al.; Research on the role of type 1 fimbriae of Salmonella enterica serotype Enteritidis in poultry to date has been focused on the intestinal phase of the infection . This study aimed to investigate the role of type 1 fimbriae in a systemic infection by intravenously inoculating chickens with a fimD mutant or its parent strain . The fimD mutant was present in the blood for 3 weeks after infection, while the wild type parent strain was cleared within the first 3 days . The fimD mutant was isolated at least as much as the parent strain from the liver and spleen for up to 3 weeks after inoculation . The wild type strain was cleared from the caeca in the second week, while the fimD mutant was isolated from the caeca for up to 3 weeks after infection . The ovaries were more heavily infected by the fimD mutant than by the wild-type strain . In the first and second week after inoculation, the oviducts were more frequently infected by the mutant strain . The eggs of birds infected with the fimD mutant were less frequently contaminated with Salmonella . The shells of the eggs were more frequently contaminated by the wild type strain than with the mutant strain . Thus, the absence of type 1 fimbriae prolongs bacteraemia, modifies reproductive tract infection and reduces egg shell contamination by Salmonella enterica serovar Enteritidis.

What Is Cell Biology?, What Is Antibiotic?, What Is Biotechnology?, What Is Bioengineering?, What Is Molecular Biology?, r, Bacteria, o, Microorganism, i, Microbiology, n, Microbe, c, Bacteriology, o, Lactobacillus, o, Streptococcal, e, Salmonella typhimurium, c, Antibiotics, r, Yeasts, c, Antimicrobial, i, Gram positive, i, Staphylococcus, n, Antibiotics, c, Haemophilus, n, S. cerevisiae, s, Bacteriophages, a, Yeasts, i, Prokaryotes, o, Yeasts, s, Antimicrobials, s, Escherichia coli, c, Cell suspensions, a, Pichia, s, Escherichia coli, n, Escherichia coli

Scientific Publications - Work Done by Microbiology Reader Bioscreen C
Agricultural Microbiology Anaerobic Microbiology Antimicrobial Susceptibility Artificial Atmosphere Bioassay of Antibiotics Biofilm Microbiology Bioreactor Technology Biotechnology Cell Biology Clinical Microbiology Environmental Microbiology Experiments with Yeast	Fermentation Food Microbiology Functional Genomics Gene Technology Growth Media Development Growth Rate and Lag Time Industrial Microbiology Medical/Pharmaceutical Field Microbiological Assay Microbiological Research Microbiology of Cosmetics go to a specific theme...	Military Microbiology Molecular Microbiology Mutagenicity and Genotoxicity Oral Microbiology Patents Postantibiotic Studies Soil Microbiology Spore Microbiology Veterinary Microbiology Waste/Wastewater Treatment Water Microbiology Wine Microbiology

� 2005 Transgalactic Ltd (manufacturer of Bioscreen C software) | Privacy Statement | P.O. Box 1393, 00101 Helsinki, Finland, phone: +358 9 85172920, fax: +358 9 8749481, e-mail: microbiology@bionewsonline.com

Last modified: May 25, 2005