Salmonella

J Food Prot, 2003 Apr, 66(4), 700 - 9
Models of antimicrobial resistance and foodborne illness: examining assumptions and practical applications; Barber DA et al.; Antimicrobial resistance is an issue of increasing global concern . Several investigators have suggested that antibiotic use in food-producing animals is a major contributor to the increasing incidence of antimicrobial-resistant organisms causing illness in humans (F . J . Angulo, K . R . Johnson, R . V . Tauxe, and M . L . Cohen, Microb . Drug Res . 6:77-83, 2000; P . D . Fey, T . J . Safranek, M . E . Rupp, E . F . Dunne, R . Efrain, P . C . Iwen, P . A . Bradford, F . J . Angulo, and S . H . Hinrichs, N . Engl . J . Med . 342:1242-1249, 2000; S . A . McEwen and P . J . Fedorka-Cray, Commun . Infect . Dis . 34(Suppl . 3):S93-S106, 2002; D . L . Smith, A . D . Harris, J . A . Johnson, E . K . Silbergeld, and J . G . Morris, Jr., Proc . Natl . Acad . Sci . USA 99:6434-6439, 2002; D . G . White, S . Zhao, R . Sudler, S . Ayers, S . Friedman, S . Chen, P . F . McDermott, D . D . Wagner, and J . Meng, N . Engl . J . Med . 345:1147-1154, 2001; W . Witte, Science 279:996, 1998) . In this paper, we discuss this and other assumptions relevant to a quantitative risk assessment model for salmonellosis in humans . We also discuss other important aspects of modeling food safety and food-associated antimicrobial resistance risk to humans . We suggest that the role of food-producing animals in the origin and transmission of antimicrobial resistance and "foodborne" pathogens has been overestimated and overemphasized in the scientific literature; consequently, nonfoodborne transmission, including pet-associated human cases, has been underemphasized . Much evidence exists for the potential contribution to infectious disease that may be of human or pet origin (that may contact humans through food but not be of a food origin) . Risk analyses that do not acknowledge the potential for these sources of cross-contamination will understate the contribution that origin has in the realm of foodborne and food-associated diseases (e.g., Salmonella) and the resulting uncertainty levels in the food system, thus leading to biased inferences . We emphasize the importance of evaluating both the foodborne and nonfoodborne transmission risk for salmonellosis and outline the basics of an analytical modeling approach in food safety with examples to illustrate strengths and limitations in the modeling . Examples illustrate, on a simplistic level, how varying assumptions and other inputs can influence the output of food-associated quantitative risk models.

J Food Prot, 2003 Apr, 66(4), 656 - 9
Incubation of supplemented egg contents pools to support rapid detection of Salmonella enterica serovar Enteritidis; Gast RK et al.; Detecting internal contamination of eggs with Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) is an important aspect of efforts to identify infected laying flocks . When egg contents pools are tested for Salmonella Enteritidis, a preliminary incubation step is often employed to allow small initial populations of contaminants to multiply to more easily detectable numbers . Consistent detection of Salmonella Enteritidis in egg pools by direct plating requires the presence of at least 10(5) CFU/ml, whereas some very rapid methods can require as many as 10(7) CFU/ml . The present study determined the rates at which initial inocula of approximately 10 Salmonella Enteritidis cells multiplied in 10-egg pools, some of which were supplemented with concentrated nonselective enrichment broth or with a source of iron . At 37 degrees C, Salmonella Enteritidis concentrations in supplemented egg pools usually reached 10(5) CFU/ml within 12 h and 10(7) CFU/ml by 12 to 15 h of incubation . At 25 degrees C, Salmonella Enteritidis concentrations in supplemented egg pools typically attained 10(5) CFU/ml by 18 to 27 h and 10(7) CFU/ml by 27 to 36 h of incubation . At both temperatures, Salmonella Enteritidis multiplication was significantly slower in unsupplemented pools . Accordingly, the length of incubation time necessary for consistent detection of small numbers of Salmonella Enteritidis in egg contents pools depends on the incubation temperature used, on whether the egg pools are supplemented to increase the rate of bacterial multiplication, and on the sensitivity of subsequent tests applied to the incubated pools.

J Food Prot, 2003 Apr, 66(4), 549 - 58
Viability of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in yellow fat spreads as affected by storage temperature; Holliday SL et al.; A study was conducted to characterize the survival and inactivation kinetics of a five-serotype mixture of Salmonella (6.23 to 6.55 log10 CFU per 3.5-ml or 4-g sample), a five-strain mixture of Escherichia coli O157:H7 (5.36 to 6.14 log10 CFU per 3.5-ml or 4-g sample), and a six-strain mixture of Listeria monocytogenes (5.91 to 6.18 log10 CFU per 3.5-ml or 4-g sample) inoculated into seven yellow fat spreads (one margarine, one butter-margarine blend, and five dairy and nondairy spreads and toppings) after formulation and processing and stored at 4.4, 10, and 21 degrees C for up to 94 days . Neither Salmonella nor E . coil O157:H7 grew in any of the test products . The time required for the elimination of each pathogen depended on the product and the storage temperature . Death was more rapid at 21 degrees C than at 4.4 or 10 degrees C . Depending on the product, the time required for the elimination of viable cells at 21 degrees C ranged from 5 to 7 days to >94 days for Salmonella, from 3 to 5 days to 28 to 42 days for E . coli O157:H7, and from 10 to 14 days to >94 days for L . monocytogenes . Death was most rapid in a water-continuous spray product (pH 3.66, 4.12% salt) and least rapid in a butter-margarine blend (pH 6.66, 1.88% salt) . E . coli O157:H7 died more rapidly than did Salmonella or L . monocytogenes regardless of storage temperature . Salmonella survived longer in high-fat (> or = 61%) products than in products with lower fat contents . The inhibition of growth is attributed to factors such as acidic pH, salt content, the presence of preservatives, emulsion characteristics, and nutrient deprivation . L . monocytogenes did not grow in six of the test products, but its population increased between 42 and 63 days in a butter-margarine blend stored at 10 degrees C and between 3 and 7 days when the blend was stored at 21 degrees C . On the basis of the experimental parameters examined in this study, traditional margarine and spreads not containing butter are not "potentially hazardous foods" in that they do not support the growth of Salmonella, E . coli O157:H7, or L . monocytogenes.

J Food Prot, 2003 Apr, 66(4), 542 - 8
Effectiveness of electrolyzed acidic water in killing Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes on the surfaces of tomatoes; Bari ML et al.; A study was conducted to evaluate the efficacy of electrolyzed acidic water, 200-ppm chlorine water, and sterile distilled water in killing Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on the surfaces of spot-inoculated tomatoes . Inoculated tomatoes were sprayed with electrolyzed acidic water, 200-ppm chlorine water, and sterile distilled water (control) and rubbed by hand for 40 s . Populations of E . coli O157:H7, Salmonella, and L . monocytogenes in the rinse water and in the peptone wash solution were determined . Treatment with 200-ppm chlorine water and electrolyzed acidic water resulted in 4.87- and 7.85-log10 reductions, respectively, in Escherichia coli O157:H7 counts and 4.69- and 7.46-log10 reductions, respectively, in Salmonella counts . Treatment with 200-ppm chlorine water and electrolyzed acidic water reduced the number of L . monocytogenes by 4.76 and 7.54 log10 CFU per tomato, respectively . This study's findings suggest that electrolyzed acidic water could be useful in controlling pathogenic microorganisms on fresh produce.

Vet Microbiol, 2003 May 29, 93(3), 223 - 33
Adhesion of Salmonella enterica serotype Enteritidis isolates to chicken isthmal glandular secretions; De Buck J et al.; The ability of Salmonella enterica serotype Enteritidis isolates to adhere to immobilized secretions of the isthmus of the laying hen was determined in an ELISA-type assay . One-third of the 56 isolates tested in the logarithmic growth phase, adhered to the isthmal secretions . Using a binding assay of the isolates to thin paraffin sections of the oviduct, we demonstrated that the receptor of the adhesion was localized inside the tubular gland cells of the isthmus . The adhesion to immobilized isthmal secretions as well as to the paraffin sections was blocked by the addition of mannose . A fimD mutant of S . Enteritidis, lacking type 1 fimbriae, did not adhere, confirming that the adhesion was mediated by type 1 fimbriae . Mannosylated glycoproteins were demonstrated in the isthmus glandular cells using confocal laser scanning microscopy by FITC-labelled Lens culinaris lectins . It is hypothesized that the binding of S . Enteritidis to isthmal secretions could play a role in the contamination of eggs through incorporation of the bacteria in the shell membranes.

Mutat Res, 2003 Apr 20, 536(1-2), 91 - 101
Carcinogenic semicarbazide induces sequence-specific DNA damage through the generation of reactive oxygen species and the derived organic radicals; Hirakawa K et al.; Semicarbazide, a hydrazine derivative, is carcinogenic to mice but shows no or little mutagenicity in the Salmonella-microsome test . To clarify whether or not the genotoxic mechanism contributes to the non-mutagenic carcinogenicity of semicarbazide, we investigated DNA damage induced by semicarbazide using 32P-5'-end-labeled DNA fragments obtained from the c-Ha-ras-1 protooncogene and the p53 tumor suppressor gene . Semicarbazide caused DNA damage frequently at the thymine and cytosine residues in the presence of Cu(II) . Catalase and bathocuproine partially inhibited DNA damage, suggesting that hydrogen peroxide plus Cu(I) participates in DNA damage . When a high concentration of semicarbazide was used in the presence of catalase, DNA damage was induced, especially at G in 5'-AG and slightly at 5'-G in GG and GGG sequences . An electron paramagnetic resonance (EPR) spectroscopic study has confirmed that the reaction of semicarbazide with Cu(II) produces carbamoyl radicals (z.rad;CONH(2)), possibly generated via the nitrogen-centered radicals of semicarbazide . Azodicarbonamide also produced carbamoyl radicals and induced DNA damage frequently at 5'-G in GG and GGG sequences, suggesting that carbamoyl radicals participate in this sequence-specific DNA damage by semicarbazide . On the basis of our previous reports, we consider that the sequence-specific DNA damage at G in 5'-AG in the present study is due to the nitrogen-centered radicals . This study has shown that semicarbazide induces DNA damage in the presence of Cu(II) through the formation of hydrogen peroxide and Cu(I) . In addition, semicarbazide-derived free radicals participate in DNA damage . DNA damage induced by these reactive species may be relevant to the carcinogenicity of semicarbazide.

J Appl Microbiol, 2003, 94(5), 826 - 35
Cross-contamination with Salmonella on a broiler slaughterhouse line demonstrated by use of epidemiological markers; Olsen JE et al.; AIMS: To investigate contamination of surfaces on a poultry slaughter line from infected poultry and subsequent cross-contamination of non-infected poultry . METHODS AND RESULTS: A broiler slaughterhouse was investigated for the presence of Salmonella on 17 defined points over two 1-week periods . Flocks supplied to slaughter and neck skin samples from processed chicken were likewise investigated . Salmonella was detected in 10 out of 18 flocks at ante-mortem inspection, while seven flocks tested positive in the finished products . Equipment at all but one control point at the slaughter line tested positive at least once during the study . The chicken receiving area was the most contaminated . By comparison of typing results from serotyping, plasmid profile typing and phage typing, direct evidence for cross-contamination with Salm . serotype Typhimurium, Salm . Serotype 4.12:b:- and Salm . serotype Virchow on the slaughter line was obtained for four of the flocks . The cleaning procedure in place did not remove all Salmonella from the contaminated areas . CONCLUSIONS: Evidence for contamination of equipment on a slaughter line and subsequent cross-contamination to non-infected chicken was provided by typing methods . SIGNIFICANCE AND IMPACT OF THE STUDY: This study has provided detailed information on cross-contamination on a slaughter line by the use of phage typing and plasmid profiling . The study stresses the importance of controlling Salmonella in the primary production, as contamination of the equipment on the slaughter line will act as a vehicle to contaminate finished products . Cleaning procedures on slaughter lines cannot be expected to control this problem with the current equipment.

J Assoc Physicians India, 2003 Jan, 51, 9 - 11
Role of modified Widal test in the diagnosis of enteric fever; Pai AP et al.; OBJECTIVES: To evaluate the diagnostic specificity of modified Widal for recent infection in comparison with conventional Widal test . METHOD: Modified widal test was simultaneously done along with conventional Widal test in serum samples obtained from 50 bacteriologically positive cases of Salmonella typhi infection as well as 50 healthy individuals . RESULTS: A four-fold difference in the titres was noticed in the 50 sera of the test group and no charge in the titres of the control group . The early rising O antibodies which are predominantly IgM in nature . These are due to recent infection and are inactivated by 2-mercaptoethanol . On the other hand H is a mixture of IgG and IgM hence IgM portion gets inactivated giving rise to fall in titre . By inactivating IgM antibodies in modified Widal test, the agglutination would be brought about only by specific IgG while in the conventional Widal test agglutination is due to specific IgG and IgM . The difference in the titres indicates specific IgM class of antibodies which is the hallmark of recent infection . CONCLUSION: If conventional Widal test and modified Widal test are simultaneously done, one can be definite about the diagnosis of enteric fever.

Jpn J Thorac Cardiovasc Surg, 2003 Feb, 51(2), 59 - 61
Successful treatment of a Salmonella aortic arch aneurysm; Hamamoto H et al.; A 52-year-old man hospitalized for hoarseness and chest pain was found in chest computed tomography to have an impending aortic arch aneurysm rupture . Laboratory studies showed the presence of severe inflammation . Based on a clinical diagnosis of infected aortic arch aneurysm, we conducted total arch replacement . Salmonella was identified in the aneurismal wall and antibiotics were administered long-term . The postoperative course was uneventful . The patient was discharged on postoperative day 48 . He has remained afebrile and asymptomatic in the 10 months since surgery but continues to take 300 mg/d of oral levofloxacin.

J Virol, 2003 May, 77(9), 5209 - 17
Attenuated Salmonella enterica serovar Typhi and Shigella flexneri 2a strains mucosally deliver DNA vaccines encoding measles virus hemagglutinin, inducing specific immune responses and protection in cotton rats; Pasetti MF et al.; Measles remains a leading cause of child mortality in developing countries . Residual maternal measles antibodies and immunologic immaturity dampen immunogenicity of the current vaccine in young infants . Because cotton rat respiratory tract is susceptible to measles virus (MV) replication after intranasal (i.n.) challenge, this model can be used to assess the efficacy of MV vaccines . Pursuing a new measles vaccine strategy that might be effective in young infants, we used attenuated Salmonella enterica serovar Typhi CVD 908-htrA and Shigella flexneri 2a CVD 1208 vaccines to deliver mucosally to cotton rats eukaryotic expression plasmid pGA3-mH and Sindbis virus-based DNA replicon pMSIN-H encoding MV hemagglutinin (H) . The initial i.n . dose-response with bacterial vectors alone identified a well-tolerated dosage (1 x 10(9) to 7 x 10(9) CFU) and a volume (20 micro l) that elicited strong antivector immune responses . Animals immunized i.n . on days 0, 28, and 76 with bacterial vectors carrying DNA plasmids encoding MV H or immunized parenterally with these naked DNA vaccine plasmids developed MV plaque reduction neutralizing antibodies and proliferative responses against MV antigens . In a subsequent experiment of identical design, cotton rats were challenged with wild-type MV 1 month after the third dose of vaccine or placebo . MV titers were significantly reduced in lung tissue of animals immunized with MV DNA vaccines delivered either via bacterial live vectors or parenterally . Since attenuated serovar Typhi and S . flexneri can deliver measles DNA vaccines mucosally in cotton rats, inducing measles immune responses (including neutralizing antibodies) and protection, boosting strategies can now be evaluated in animals primed with MV DNA vaccines.

Klin Lab Diagn, 2003 Feb, (2), 51 - 2
{Rare serotypes of salmonella circulating in Kazakhstan}; Tabaeva AA et al.; The serotypic picture of rare-type salmonellas, isolated in the South region of Kazakhstan, was studied . The circulation of 31 serotypes of 17 groups was established . The circulation of serotypes 0:13, 0:38, 0:44 serogroups, was found among people (patients and bacterium-carriers) . Serotypes 0:28, 0:42, 0:62, 0:66 serogroups, were isolated only from the environment . The combined circulation (patients, bacterium-carriers, environment) was registered for seroviruses 0:14, 0:35 and serogroups 0:58 . The obtained data suggested that separate rare salmonella types area tied to ecology.

J Clin Microbiol, 2003 Apr, 41(4), 1617 - 22
Analysis of molecular epidemiology of Chilean Salmonella enterica serotype enteritidis isolates by pulsed-field gel electrophoresis and bacteriophage typing; Fernandez J et al.; Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994 . S . enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions . A study was planned to characterize this epidemic using the best discriminatory typing technique . Research involved 441 S . enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates . The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis . The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993) . A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods . Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch . Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S . enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S . enterica serotype Enteritidis in 1994 . Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001) . Food and poultry isolates matched the predominant S . enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S . enterica serotype Enteritidis subtypes identified in the north of Chile . The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S . enterica serotype Enteritidis subtypes were associated with epidemic changes.

J Clin Microbiol, 2003 Apr, 41(4), 1469 - 79
DNA fingerprinting of Salmonella enterica subsp . enterica serovar typhimurium with emphasis on phage type DT104 based on variable number of tandem repeat loci; Lindstedt BA et al.; Seventy-eight human and environmental strains of Salmonella enterica subsp . enterica serovar Typhimurium, as well as 18 isolates of other Salmonella serovars and 6 isolates of Escherichia coli, were subjected to a novel variable number of tandem repeats (VNTR)-based fingerprinting method that showed high discrimination and reproducibility for typing serovar Typhimurium isolates . The method is based on capillary separation of PCR products from fluorescence-labeled VNTR in the serovar Typhimurium genome . The serovar Typhimurium isolates displayed 54 VNTR patterns, and the VNTR assay correctly identified strains from a well-characterized outbreak . Among 37 serovar Typhimurium phage type DT104 isolates, 28 distinct VNTR patterns were found . This VNTR-based method is fast and suitable for complete automation . Our VNTR-based method was capable of high discrimination within the homogeneous serovar Typhimurium DT104 phage type and can be used to trace outbreaks and to monitor DT104 as well as other phage types . The VNTR assay was compared to XbaI pulsed-field gel electrophoresis, amplified fragment length polymorphism analysis, integron-cassette profiles and gene PCR of intI1, qacEDelta1, sulI1, and floR . The VNTR assay showed greatly improved resolution compared to all other tested methods in this study.

Microbiol Immunol, 2003, 47(2), 161 - 5
Screening method for Salmonella enterica serovar Typhi and serovar Paratyphi A with reduced susceptibility to fluoroquinolones by PCR-restriction fragment length polymorphism; Hirose K et al.; Salmonella enterica serovar Typhi and serovar Paratyphi A with reduced susceptibility to fluoroquinolones (MICs of ciprofloxacin, 0.25 to 2 microg/ml) have a mutation at codon either Ser-83 or Asp-87 of gyrA gene . A screening method by PCR-restriction fragment length polymorphism (PCR-RFLP) was designed to screen the mutations at codon Ser-83 and Asp-87 of the gyrA gene of S . enterica serovar Typhi and serovar Paratyphi A clinical isolates . This method successfully screened the gyrA mutations of S . enterica serovar Typhi and serovar Paratyphi A with reduced susceptibility to fluoroquinolones.

Russ J Immunol, 2000 Jul, 5(2), 209 - 216
Application of Transmission Electron Microscopy for Analysis of Ultrastructural Organization of Circulating Immune Complexes in Patients with Typhoid Fever and Chronic Carriers of Salmonella typhi; Didenko LV et al.; Transmission electron microscopy was used to study the ultrastructural organization of circulating immune complexes (CIC), isolated from patients with typhoid fever in the different periods of acute infectious process (febrile period, period of an early and late reconvalescence), relapse and from acute and chronic carriers of Salmonella typhi in the period of pathogen excreting . It has been shown that preparations of CIC from healthy donors consisted of amorphous mean electron density material, including a cell-like detritus . At acute and chronic infectious process there were bacterial cells in a structure of the CIC . Depending on the period of disease, bacteria had different ultrastructural organization in the CIC . In the febrile period, in the period of an early reconvalescence and in the period of formation of acute carriage of S . typhi, and also in relapse, bacteria had a typical structure, with reference to gram-negative microorganisms . In the period of formation of acute and chronic carriers of S . typhi, in a period of excretion of S . typhi, bacteria in the CIC had ultrastructural organization, relevant to the forms of bacteria with a defective cell wall . Immunocytochemistry research made with the purpose of visualization the O-antigen of S . typhi in bacteria has demonstrated positive immunolabeling on the O-antigen in the bacterial forms and forms with a defective cell wall, and on amorphous mean electron density material . The analysis of ultrastructural organization of the circulating immune complexes and immunolabeling on the O-antigen of S . typhi have allowed to conclude that S . typhi, both typical bacterial form, and the forms with a defective cell wall were the main structural component of circulating immune complexes in acute and chronic forms of infectious process.

Microbiology, 2003 Apr, 149(Pt 4), 925 - 39
Genetic modulation of Shigella flexneri 2a lipopolysaccharide O antigen modal chain length reveals that it has been optimized for virulence; Morona R et al.; The lipopolysaccharide (LPS) molecules of Shigella flexneri 2a have O antigen (Oag) polysaccharides with two modal chain length distributions . The chromosomal wzz(SF) gene results in short (S) type Oag chains {11-17 Oag repeat units (RUs)}, and the pHS-2 plasmid-located wzz(pHS2) gene results in very long (VL) type Oag chains (>90 Oag RUs) . S . flexneri wzz(SF) mutants are unable to form plaques on HeLa cell monolayers and F-actin comet tails, indicating that IcsA/VirG function in actin-based motility (ABM) is defective . An S . flexneri wzz(SF) wzz(pHS2) double mutant had LPS with relatively short, random length Oag chains and, paradoxically, was able to form plaques and F-actin comet tails . The influence of Oag modal chain length distribution on virulence and related properties was investigated using complementation with different wzz genes . Wzz(O139) from Vibrio cholerae O139 and Wzz(ST) from Salmonella enterica serovar Typhimurium were fully functional in Shigella flexneri, resulting in LPS with either very short (VS) type Oag chains (2-7 Oag RUs) or long (L) type Oag chains (19-35 RUs), respectively . In the absence of VL-type Oag chains, the VS-, S- and L-type Oag chains were permissive for plaque and F-actin comet tail formation . However, in the presence of LPS with VL-type Oag chains, the VS- and S-type Oag chains but not the L-type Oag chains were permissive for plaque and F-actin comet tail formation . These data, and the results of a previous investigation, show that IcsA function in ABM requires LPS Oag chains with at least two but less than 18 RUs when VL-type Oag chains are co-expressed on the cell surface . However, in the absence of the VL-type Oag chains, LPS Oag chains with at least two but less than 90 RUs are able to support IcsA function in ABM . Indirect immunofluorescence staining of IcsA on the cell surface of the S . flexneri strains did not correlate with the observed effect of Oag chain length on plaque and F-actin comet tail formation . However, when intracellular bacteria lacking VL-type Oag chains were examined, an inverse correlation between Oag modal chain length and detection of IcsA was observed, i.e . staining decreased with increased modal length . It is hypothesized that Oag chains can mask IcsA and interfere with its function in ABM, and a model is presented to explain how LPS Oag and IcsA may interact . It is suggested that S . flexneri 2a has evolved to synthesize LPS with two Oag modal chain lengths, as S-type Oag chains allow IcsA to function in ABM in the presence of VL-type Oag chains that confer resistance to serum.

Scand J Infect Dis, 2003, 35(1), 67 - 8
Postoperative mediastinitis due to Salmonella; Fernandez-Ayala M et al.; Mediastinitis remains one of the most serious and dreaded complications of median sternotomy . Salmonella is a rare cause of mediastinal infection . The case is reported of a patient who underwent heart valve surgery and developed a Salmonella enteritidis bacteraemia in the postoperative period, which caused aortic dissection and mediastinitis.

Indian J Chest Dis Allied Sci, 2003 Jan-Mar, 45(1), 75 - 7
Pneumonia due to an unusual serotype of Salmonella; Ghadage DP et al.; Salmonella species is a rare cause of infection in the respiratory tract . Pleuropulmonary infection with these organisms are however associated with high mortality . We report a case where serotype Worthington was isolated from a patient of acute pneumonia.

Comb Chem High Throughput Screen, 2003 Mar, 6(2), 161 - 6
SAR modeling: effect of experimental ambiguity; Thampatty BP et al.; The applicability of SAR (structure-activity relationship) techniques to data obtained using high throughput screening (HTS) and toxicogenomic techniques is explored . The reason for this study derives from the fact that for economical and time considerations HTS bioassays may consist of single determinations, i.e . lack of duplication . This introduces an element of uncertainty . Using two different data bases of fairly complex biological phenomena (allergic contact dermatitis in humans and the induction of mutations in Salmonella), it is demonstrated that the resulting SAR models can tolerate up to 20% ambiguity in the experimental data.

Comb Chem High Throughput Screen, 2003 May, 6(3), 235 - 44
The use of fluorescence polarization assays for the detection of infectious diseases; Jolley ME et al.; Fluorescence Polarization Assays (FPAs) have been shown to have great utility in the detection of infectious diseases . Examples are presented of the use of O-polysaccharides (OPSs) for the detection of antibodies in serum, whole milk and whole blood to gram negative organisms (Brucella spp., Salmonella spp.) . The use of proteins and peptides are also described for the detection of Mycobacterium bovis and Equine Infectious Anemia Virus . Fluorescence Polarization Inhibition Assays (FPIAs) are discussed for the specific and sensitive detection and quantitation of Salmonella spp . cells from culture . An example of the detection of enterohemorrhagic E . coli (EHECS) by Strand Displacement Amplification (SDA), coupled with FP, down to the single cell level, within thirty minutes, is described.

East Afr Med J, 2002 Dec, 79(12), 633 - 9
Non-typhi salmonella in children with severe malaria; Oundo JO et al.; OBJECTIVE: To determine the association between Plasmodium falciparum malaria and non-typhi Salmonella in children . DESIGN: Cross-sectional hospital based study . SETTING: Kilifi District Hospital (KDH) between January 1997 and June 2001 . SUBJECTS: Children aged between three months to 123 months (mean age 28.28 months) and who had been admitted to the paediatric or High Dependency Research Ward (HDRW) of the KDH . METHODS: A total of 19, 118 blood cultures routinely obtained for all admissions and 1,820 clinically indicated stools samples were obtained from 9,147 children admitted with malaria . The specimens were cultured and antibiotic sensitivity done using standard laboratory procedures with stringent internal and external quality control in place . RESULTS: The total bacterial pathogens isolated from blood and stool were 1,395/19,118 (7.3%) and 342/1,820 (19%) respectively . Non-typhi salmonella consisted of 260/1,395 (18.6%) of the positive blood cultures and 92/324 (28.4%) of the stool cultures out of which a total of 101 NTS occurred in children with severe malaria . Out of the 9,147 malaria cases admitted, 101/9,147 (1.10%) had concomitant NTS infection . NTS with severe malaria as a proportion of all malaria admissions for the period varied between 0.8% and 1.5% . There was a significant association (p-value=0.032) between clinical outcome of death and female sex of the patient . The NTS isolates which occurred with severe malaria showed various levels of antibiotic resistance . They were resistant to ampicillin (35%), chloramphenicol (18%), gentamicin (22%), cefuroxime (29%), sulphamethoxazole-trimethoprim (39%), ciprofloxacin (3%), cefotaxime (14%), amoxycillin-clavulanic acid (26%) and tobramycin (18.0%) . Multidrug resistance (MDR) was seen in 34 (33.6%) of the isolates . CONCLUSIONS: NTS and severe malaria occurring together are a problem in this area and that a large number of the isolates are MDR . An elaborate case-controlled study is required to elucidate the chain of events of both NTS and malaria parasite co-existence.

J Environ Pathol Toxicol Oncol, 2003, 22(1), 69 - 76
Bioassay-guided isolation of antimutagenic factors from fruits of Terminalia bellerica; Kaur S et al.; In the course of our search for novel polyphenolic antimutagenic agents from medicinal plants, we examined water, acetone, and chloroform extracts of Terminalia bellerica for their antimutagenic potency using the Ames Salmonella/microsome assay . Acetone extract exhibited variable inhibitory activity of 65.6%, and 69.7% with 4-O-nitrophenylenediamine (NPD) and sodium azide, respectively (as direct-acting mutagens), and 81.4% with 2-aminofluorene (2AF) (an S9-dependent mutagen), in the preincubation mode of experimentation . Inhibition with chloroform and water extracts was rather insignificant . Studies are well underway to isolate and identify the active polyphenolic compounds from acetone extract, which could be used as effective chemopreventive agents in the future.

J Environ Pathol Toxicol Oncol, 2003, 22(1), 59 - 67
Studies on correlation of antimutagenic and antiproliferative activities of Juglans regia L; Kaur K et al.; We investigated the effect of water and acetone extract of Juglans regia L . to evaluate its antimutagenic and antiproliferative activities . The antimutagenic study using TA98 and TA100 tester strains of Salmonella revealed the water and acetone extracts to be more effective than the benzene and chloroform extracts in inhibiting the revertants induced by 2-aminoflourene (2AF) in TA100 tester strains . The most effective extracts in the Ames assay were further evaluated using the Lucifer luciferase assay and in time course studies for antiproliferative activities using the Hoechst staining to observe apoptotic cell deaths . The acetone extract showed a correlation of antimutagenic activities in the Ames assay with its antiproliferative effect in different cell lines, while the water extract exerted its effect distinctly in each cell line . Further studies are still needed to evaluate the cytotoxicity in experiments carried out in vivo.

Can Vet J, 2003 Mar, 44(3), 230 - 1
Prevalence of Salmonella in dairy herds in Alberta; Sorensen O et al.; Fifty dairy herds in Alberta were tested for the presence of Salmonella . Four (8%) dairy herds had at least 1 cow shedding Salmonella . Different isolates were identified by serotyping, phage typing, and antibiotic resistance patterns . Pulsed-field gel electrophoresis patterns were determined for unique isolates.

Proc Natl Acad Sci U S A, 2003 Apr 15, 100(8), 4706 - 11 Epub 2003 Apr 03.
Closing the loop: the PmrA/PmrB two-component system negatively controls expression of its posttranscriptional activator PmrD; Kato A et al.; A fundamental question in biology is how an organism integrates multiple signals to mediate an appropriate cellular response . The PmrAPmrB two-component system of Salmonella enterica can be activated independently by Fe(3+), which is sensed by the PmrB protein, and in low Mg(2+), which is sensed by the PhoQ protein . The low-Mg(2+) activation requires pmrD, a PhoPPhoQ-activated gene that activates the response regulator PmrA at a posttranscriptional level . We now report that pmrD expression is negatively regulated by the PmrAPmrB system . Conditions that activate the PmrA protein independently of pmrD, such as exposure to Fe(3+), resulted in lower levels of pmrD transcription . The PmrA protein footprinted the pmrD promoter upstream of the PhoP-binding site but did not interfere with binding of the PhoP protein . Mutation of the PmrA-binding site in the pmrD promoter abolished PmrA-mediated repression . Negative regulation of the PhoPPhoQ-activated pmrD gene by the PmrAPmrB system closes a regulatory circuit designed to maintain proper cellular levels of activated PmrA protein and constitutes a singular example of a multicomponent feedback loop.

Bioresour Technol, 2003 Aug, 89(1), 49 - 56
Transport and survival of bacterial and viral tracers through submerged-flow constructed wetland and sand-filter system; Vega E et al.; Untreated or improperly treated wastewater has often been cited as the primary contamination source of groundwater . The use of decentralized wastewater treatment systems has applicability around the world since it obviates the need for extensive infrastructure development and expenditures . The use of a submerged flow constructed wetland (CW) and a sand filter to remove bacterial and viral pathogens from wastewater streams was evaluated in this study Salmonella sp . and a bacteriophages tracer were used in conjunction with the conservative bromide tracer to understand the fate and transport of these organisms in these treatment systems . Viral breakthrough numbers in the sand filter and CW were similar with a Spearman Rank correlation of 0.8 (P<0.05) . In the CW, the virus exhibited almost a 3-log reduction, while in the sand filter, the viruses exhibited a 2-log reduction . The bacterial tracers, however, did not exhibit similar reductions . Low numbers of bacteria and viruses were still detectable in the effluent streams suggesting that disinfection of the effluent is critical . The survival of the tracer bacteria and viruses was as expected dependent on the biotic and abiotic conditions existing within the wastewater . The results suggest that the microbial removal characteristics of decentralized wastewater treatment systems can vary and depend on factors such as adsorption, desorption and inactivation which in turn depend on the design specifics such as filter media characteristics and local climatic conditions.

Thromb Res, 2002 Dec 15, 108(5-6), 329 - 34
Consumption of plasma factor VII in a rabbit model of non-overt disseminated intravascular coagulation; Clarke BJ et al.; INTRODUCTION: We have recently described an experimental animal model of non-overt disseminated intravascular coagulation (DIC) in the rabbit in which the induction of tissue factor (TF) mRNA and TF antigen expression in peripheral blood leukocytes (PBL) was demonstrated to occur within 2 h of administration of low-dose endotoxin {Hematol . J . 2 (2001) 188} . In the present study, we demonstrate that the leukocyte TF expressed has procoagulant activity leading to a rapid decline in the concentration of factor VII (FVII) in rabbit plasma . METHODS: Total plasma FVII antigen and FVIIa were quantitated by rabbit FVII-specific immunoassay and FVIIa-specific clotting assays, respectively . Plasma samples from either saline-injected rabbits or rabbits administered a single bolus of 10 microg/kg Salmonella lipopolysaccharide were compared over a 24-h period . RESULTS: Total plasma FVII antigen decreased progressively post-endotoxin injection, reaching 71% of the baseline concentration at 8 h (p<0.001, n=18), and remained low (78%) at 24 h post-injection (p<0.01, n=16), returning to normal by 48 h . Plasma FVIIa levels increased to 120% within 2 h of endotoxin injection, fell to 73% of the baseline concentration at 8 h (p<0.05, n=18) and returned to normal by 24 h post-endotoxin administration . Procoagulant activity of rabbit peripheral blood leukocytes was enhanced at 2 h (p<0.01, n=6) and 4 h (p<0.05, n=6) post-endotoxin injection . The prothrombin time (PT) was increased by <3 s, and thrombin-antithrombin (TAT) complex formation was not significantly increased in the plasma of endotoxin-treated rabbits . No significant changes in total plasma FVII antigen, FVIIa or leukocyte procoagulant activity were observed in rabbits treated with saline . CONCLUSIONS: We conclude that the activation of FVII to FVIIa and rapid consumption of total FVII/FVIIa occur very early and likely are integral events linked to the initiation and propagation of non-overt DIC induced by endotoxin.

J Appl Microbiol, 2003, 94 Suppl, 114S - 119S
The rise and fall of Salmonella Enteritidis in the UK; Cogan TA et al.; After rising in the early 1980s, the number of recorded human cases of Salmonella enterica subsp . enterica in the UK has fallen in the last 5 years, with a particular decline in cases of infection with serovar Enteritidis . This decline has been concomitant with the introduction of vaccination of egg-laying hens against serovar Enteritidis . It is likely that other factors such as improved biosecurity in egg-laying flocks, a build-up of immunity in other animals and the rise in the number of livestock infections with host-adapted serovars of Salmonella have also played a part in this decline . Although human Salmonella cases are currently at their lowest level since 1987, it is important to remember that the reasons for the dominance of Enteritidis in human infection are poorly understood and it is possible that other serovars could share similar properties and the eradication of Enteritidis may leave a niche for them to fill.

Mol Microbiol, 2003 Apr, 48(2), 573 - 85
Protein-peptidoglycan interactions modulate the assembly of the needle complex in the Salmonella invasion-associated type III secretion system; Pucciarelli MG et al.; The invasion-associated type III secretion system of Salmonella enterica assembles as a supra-molecular structure, termed needle complex, which spans the bacterial envelope . Here, we present evidence for protein-peptidoglycan interactions that modulate the assembly of this organelle . The presence of major membrane components of the needle complex (PrgH, PrgK and InvG) and InvH, required for efficient assembly of the organelle, was examined in peptidoglycan purified by extensive boiling of bacteria in 4% SDS . InvH, PrgH and PrgK, but not InvG, were detected in this purified material . InvH was present in the peptidoglycan in higher relative amounts than PrgH or PrgK, and was the only protein efficiently bound to peptidoglycan in cross-linking experiments . Analysis in mutants defective for needle complex proteins showed that the needle proteins PrgI and PrgJ and, to a lesser extent, InvH, sustain the association of PrgH and PrgK with peptidoglycan . In contrast, the association of InvH with peptidoglycan did not necessitate other needle complex proteins . Functional analysis showed that the association of InvH, PrgH and PrgK with peptidoglycan is abolished in live bacteria carrying structural modifications in the peptidoglycan . The loss of these interactions caused a marked reduction in the number of needle complexes and, concomitantly, in protein secretion and bacterial invasion of cultured eukaryotic cells . Altogether, these data provide the first evidence for an association between proteins of the Salmonella needle complex and the peptidoglycan . In addition, we demonstrate that these protein-peptidoglycan interactions are critical for an efficient and correct assembly of this specialized organelle.

Mol Microbiol, 2003 Apr, 48(2), 549 - 59
The role of DNA base excision repair in the pathogenesis of Salmonella enterica serovar Typhimurium; Suvarnapunya AE et al.; The intracellular pathogen, Salmonella enterica serovar Typhimurium, is able to proliferate in phagocytes, although reactive oxygen and nitrogen intermediates are lethal to most phagocytosed bacteria . To determine whether repair of oxidatively damaged DNA is involved in S . typhimurium intramacrophage proliferation, null mutants of the DNA base excision repair (BER) system were generated . These mutants were deficient in discrete enzymes (Deltanth, Deltanei, Deltaxth, Deltanfo) or in the defined glycosylase (Deltanth/nei) and endonuclease (Deltaxth/nfo) steps . In this study, S . typhimurium BER mutants are characterized for the first time . In vitro characterization of the Salmonella BER mutants revealed phenotypes that are mostly consistent with characterized Escherichia coli BER mutants . These strains were used to evaluate the role of BER in the context of Salmonella virulence . S . typhimurium Deltaxth and Deltaxth/nfo were significantly impaired for survival in both cultured and primary macrophages activated with interferon (IFN)-gamma . Survival of Deltaxth and Deltaxth/nfo was improved nearly to wild-type levels in activated primary macrophages lacking both phagocyte oxidase and inducible nitric oxide synthase . In the murine typhoid fever model, Deltanth/nei was fivefold attenuated and Deltaxth/nfo was 12-fold attenuated compared with wild type . These data indicate that DNA oxidation is a mechanism that macrophages use to damage intracellular Salmonella, and suggest that BER-mediated repair of this damage may be important in the establishment of Salmonella infection . We speculate that adaptation to a pathogenic lifestyle may influence the acquisition and retention of redundant BER enzymes.

Mol Microbiol, 2003 Apr, 48(2), 385 - 400
virK, somA and rcsC are important for systemic Salmonella enterica serovar Typhimurium infection and cationic peptide resistance; Detweiler CS et al.; Salmonella must express and deploy a type III secretion system located in Salmonella pathogenicity island 2 (SPI-2) in order to survive in host phagocytic vacuoles and to cause systemic infection in mouse models of typhoid fever . A genome-wide approach to screening for Salmonella genes that are transcriptionally co-regulated in vitro with SPI-2 genes was used to identify bacterial loci that might function in a mouse model of systemic disease . Strains with mutations in three SPI-2 co-expressed genes were constructed and tested for their ability to cause disease in mice . We found that virK, a homologue of a Shigella virulence determinant, and rcsC, a sensor kinase, are important at late stages of infection . A second Salmonella gene that has VirK homology, somA, is also important for systemic infection in mice . We have shown that expression of both virK and somA requires the transcription factor PhoP, whereas rcsC does not . Additionally, rcsC expression does not require the transcription factor OmpR, but expression of one of the known targets of RcsC, the yojN rcsB putative operon, does require OmpR . virK, somA and rcsC are expressed in tissue culture macrophages and confer Salmonella resistance to the cationic peptide polymyxin B . We conclude that virK, somA and rcsC are important for late stages of Salmonella enteric fever, and that they probably contribute to the remodelling of the bacterial outer membrane in response to the host environment.

J Mol Microbiol Biotechnol, 2003, 5(1), 17 - 28
Acid shock accumulation of sigma S in Salmonella enterica involves increased translation, not regulated degradation; Audia JP et al.; Enteric pathogens such as Salmonella enterica and Escherichia coli face the daunting task of surviving passage through the extremely acid pH of the stomach in order to establish an infection in the host intestinal tract . These organisms have evolved elaborate stress response systems that aid in survival . The alternative sigma factor sigma(S) is a key regulator of many stress responses in S . enterica and is regulated at the levels of transcription, translation, and protein stability . Of these control mechanisms, proteolysis has been considered paramount in determining sigma(S) levels in the cell . Until the current report, acid shock was thought to increase sigma(S) levels by directly regulating degradation . However, mutant strains unable to degrade sigma(S) still exhibited acid shock induction of sigma(S) . We demonstrate here that RPOS translation is a major focus of acid stress control and is responsible for the observed increase in sigma(S) levels . A series of deletions of the 566-nucleotide untranslated region of the RPOS mRNA were constructed to examine the importance of this regulatory region in acid shock induction of RPOS . Progressive deletions starting from the 5' end of the RPOS message produced alternating loss and recovery of acid shock control . The results suggest that competing stem-loop structures work in concert to control the acid shock induction of RPOS . Further, the half-life of sigma(S) was unchanged in response to acid shock and over-expression of the MviA recognition protein resulted in constitutive sigma(S) degradation under acid stress conditions . The data indicate that in log phase, nonstressed cells increasing sigma(S) production is sufficient to increase protein half-life . In toto, these results suggest that acid shock stabilization of sigma(S) is the result of increased synthesis via translational control and does not involve changes in the activity of the MviA (RssB/SprE) ClpXP degradation complex . Therefore, constitutive degradation may enable the cell to reset the level of sigma(S) once acid stress is alleviated .

Phytother Res, 2003 Mar, 17(3), 269 - 73
Mutagenic and antimutagenic potential of the medicinal plants M . laevigata and C . xanthocarpa; Fernandes JB et al.; Aqueous extracts of medicinal plants (Mikania laevigata and Campomanesia xanthocarpa) were screened for the presence of mutagenic activity in the Salmonella/microsome assay . The extracts of Campomanesia xanthocarpa showed frameshift (TA97a strain) signs of mutagenic activity without exogenous metabolism (S9 fraction) . The infusions of Mikania laevigata, negative for mutagenic activity, showed high percentages of inhibition of mutagenesis induced by mutagens 2AF (2-amino fluorene), in the presence of exogenous metabolism (S9 fraction), for frameshift (TA98) and base pair substitution (TA100) lesions . In addition, these inhibitions were observed against mutagen SAZ (sodium azide) in assays with the TA100 strain, without exogenous metabolism (S9 fraction) . A synergistic effect was also observed in frameshift mutagenic events, with direct action in the presence of 4NQO (4-oxide-1-nitroquinoline) and a tendency to a low percentage of action enhancement, in the presence of the 2AF mutagen . The variable responses observed in the extract assays show the potentials for interaction of the different active principles in genetic material .

Eur J Immunol, 2003 Apr, 33(4), 950 - 61
Combinatorial immunoglobulin light chain variability creates sufficient B cell diversity to mount protective antibody responses against pathogen infections; Senn BM et al.; To analyze how combinatorial light (L) chain diversity influences the B cell repertoire, we studied mice with a homozygous immunoglobulin-heavy-chain null mutation (mu MT), in which the B cell developmental block was overridden by the expression of a transgenic immunoglobulin mu heavy (H) chain derived from a vesicular stomatitis virus Indiana serotype (VSV-IND)-neutralizing Ab (T11 mu MT mice) . The randomly integrated transgene could not undergo secondary rearrangements and was expressed in combination with endogenous kappa or lambda chains . T11 mu MT mice had a skewed B cell repertoire as evidenced by 30-60% VSV-IND-specific peripheral B cells and spontaneous VSV-IND-neutralizing serum titers . Upon immunization, T11 mu MT mice mounted specific IgM antibody responses against VSV-IND but, interestingly, they also responded against VSV New Jersey serotype (VSV-NJ), lymphocytic choriomeningitis virus, poliovirus and Salmonella typhi porins . Variable-region sequence analysis revealed that VSV-NJ-specific antibodies expressed numerous L chains in combination with the transgenic H chain, which was devoid of hypermutations . Thus, in T11 mu MT mice combinatorial L chain variability alone is able to build up a sufficiently complex B cell repertoire to mount protective immunoglobulin responses against a variety of pathogens.

Immunogenetics, 2003 Mar, 54(12), 817 - 29 Epub 2003 Feb 21.
Genetic variations in the interleukin-12/interleukin-23 receptor (beta1) chain, and implications for IL-12 and IL-23 receptor structure and function; van de Vosse E et al.; Cell-mediated immunity (CMI) plays an essential role in human host defense against intracellular bacteria . Type-1 cytokines, particularly gamma interferon (IFN-gamma), interleukin-12 (IL-12), and IL-23, the major cytokines that regulate IFN-gamma production, are essential in CMI . This is illustrated by patients with unusual severe infections caused by poorly pathogenic mycobacteria and Salmonella species, in whom genetic deficiencies have been identified in several key genes in the type-1 cytokine pathway, including IL12RB1, the gene encoding the beta1 chain of the IL-12 and IL-23 receptors . Several mutations in IL12RB1 with deleterious effects on human IL-12R function have been identified, including nonsense and missense mutations . In addition, a number of coding IL12RB1 polymorphisms have been reported . In order to gain more insight into the effect that IL12RB1 mutations and genetic variations can have on IL-12Rbeta1 function, three approaches have been followed . First, we determined the degree of conservation at the variant amino acid positions in IL-12Rbeta1 between different species, using known deleterious mutations, known variations in IL-12Rbeta1, as well as novel coding variations that we have identified at position S74R and R156H . Second, we analyzed the potential impact of these amino acid variations on the three-dimensional structure of the IL-12Rbeta1 protein . Third, we analyzed the putative functions of different IL-12Rbeta1 domains, partly based on their homology with gp130, and analyzed the possible effects of the above amino acid variations on the function of these domains . Based on these analyses, we propose an integrated model of IL-12Rbeta1 structure and function . This significantly enhances our molecular understanding of the human IL-12 and IL-23 systems.

J Bacteriol, 2003 Apr, 185(8), 2485 - 92
Substrate specificity classes and the recognition signal for Salmonella type III flagellar export; Hirano T et al.; Most flagellar proteins of Salmonella are exported to their assembly destination via a specialized apparatus . This apparatus is a member of the type III superfamily, which is widely used for secretion of virulence factors by pathogenic bacteria . Extensive studies have been carried out on the export of several of the flagellar proteins, most notably the hook protein (FlgE), the hook-capping protein (FlgD), and the filament protein flagellin (FliC) . This has led to the concept of two export specificity classes, the rod/hook type and the filament type . However, little direct experimental evidence has been available on the export properties of the basal-body rod proteins (FlgB, FlgC, FlgF, and FlgG), the putative MS ring-rod junction protein (FliE), or the muramidase and putative rod-capping protein (FlgJ) . In this study, we have measured the amounts of these proteins exported before and after hook completion . Their amounts in the culture supernatant from a flgE mutant (which is still at the hook-type specificity stage) were much higher than those from a flgK mutant (which has advanced to the filament-type specificity stage), placing them in the same class as the hook-type proteins . Overproduction of FliE, FlgB, FlgC, FlgF, FlgG, or FlgJ caused inhibition of the motility of wild-type cells and inhibition of the export of the hook-capping protein FlgD . We also examined the question of whether export and translation are linked and found that all substrates tested could be exported after protein synthesis had been blocked by spectinomycin or chloramphenicol . We conclude that the amino acid sequence of these proteins suffices to mediate their recognition and export.

J Biol Chem, 2003 Jun 6, 278(23), 20708 - 15 Epub 2003 Mar 31.
The YggX protein of Salmonella enterica is involved in Fe(II) trafficking and minimizes the DNA damage caused by hydroxyl radicals: residue CYS-7 is essential for YggX function; Gralnick JA et al.; Previous work from our laboratory identified YggX as a protein whose accumulation increased the resistance of Salmonella enterica to superoxide stress, reversed defects attributed to oxidized {Fe-S} clusters, and decreased the spontaneous mutation frequency of the cells . Here we present work aimed at determining why the accumulation of YggX correlates with reduced mutation frequency . Genetic and biochemical data showed that accumulation of YggX reduced the damage to DNA by hydroxyl radicals . The ability of purified YggX to protect DNA from Fenton chemistry mediated damage in vitro and to decrease the concentration of Fe(II) ions in solution available for chelation provided a framework for the interpretation of data obtained from in vivo experiments . The interpretation of in vitro assay results, within the context of the in vivo phenotypes, was validated by a mutant variant of YggX (C7S) that was unable to function in vivo or in vitro . We propose a model, based on data presented here and reported earlier, that suggests YggX is a player in Fe(II) trafficking in bacteria.

FEMS Microbiol Lett, 2003 Mar 28, 220(2), 181 - 6
Exposure of Salmonella Enteritidis to chlorine or food preservatives decreases {corrected} susceptibility to antibiotics; Potenski CJ et al.; Mutants of Salmonella Enteritidis selected following exposure to the sanitizer chlorine or to the preservatives sodium nitrite, sodium benzoate or acetic acid show resistance to multiple antibiotics (tetracycline, chloramphenicol, nalidixic acid, and ciprofloxacin) . Complementation experiments with a functional marR restored antibiotic susceptibility of selected mutants to levels similar to wild-type strains, suggesting that mar mutation was responsible for resistance . The multiple antibiotic resistance (mar) operon is a global regulator controlling intrinsic resistance towards structurally and functionally unrelated antibiotics and other noxious agents . Mutants selected after exposure to an inducing agent maintained elevated antibiotic resistance after serial subculture in media void of the inducing agent . Results highlight the importance of monitoring the use of antimicrobial agents to ensure that concentrations capable of inactivating target pathogens are used.

Curr Opin Mol Ther, 2003 Feb, 5(1), 10 - 9
Live attenuated bacteria as vectors to deliver plasmid DNA vaccines; Dietrich G et al.; Live attenuated bacterial vaccines allow vaccination via the mucosal surfaces and specific targeting to professional antigen presenting cells located at the inductive sites of the immune system . A novel approach exploits attenuated intracellular bacteria as a delivery system for eukaryotic antigen expression vectors (so-called DNA vaccines) . Candidate carrier bacteria include attenuated strains of Salmonella, Shigella and Listeria spp, which have been shown, in vitro, to deliver DNA vaccines to human cells . Bacterial DNA vaccine delivery has also demonstrated in vivo efficacy in several experimental animal models of infectious diseases and tumors . The next step should be the clinical assessment of the safety, immunogenicity and efficacy of DNA vaccine delivery by live bacterial vaccines.

J Antimicrob Chemother, 2003 May, 51(5), 1287 - 91 Epub 2003 Mar 28.
Antimicrobial resistance in clinical isolates of Salmonella enterica serotype Enteritidis: relationships between mutations conferring quinolone resistance, integrons, plasmids and genetic types; Soto SM et al.; In 481 clinical isolates of Salmonella enterica serotype Enteritidis collected from a Spanish region in 2000, 108, 83 and four isolates were resistant, respectively, to nalidixic acid, ampicillin or both . Nalidixic acid resistance was the result of DNA gyrase mutations involving the codons Asp-87 (97 isolates) and Ser-83 (15 isolates) of the gyrA gene; no mutations in parC were detected . In ampicillin-resistant strains, blaTEM genes located on plasmids and/or the chromosome were implicated . Five plasmids containing blaTEM1-like genes were identified, ranging from 7 to 100 kb, four of which were self-transferable; one of these contained a class 1 sul1 integron with an aadA1a gene cassette . This integron was also found on the chromosome of an isolate resistant to ampicillin, streptomycin and sulfadiazine . A relationship between a 40 kb self-transferable plasmid and strains of Salmonella Enteritidis phage type 6a with a distinctive RAPD profile was established.

Trends Cell Biol, 2003 Apr, 13(4), 204 - 9
Caspase-1 activation by Salmonella; Jarvelainen HA et al.; Salmonella is an interesting example of how the selective pressure of host environments has led to the evolution of sophisticated bacterial virulence mechanisms . This microbe exploits the first-line of defence, the macrophage, as a crucial tool in the initiation of disease . After invasion of intestinal macrophages, a virulence protein secreted by Salmonella specifically induces apoptotic cell death by activating the cysteine protease caspase-1 . The pro-apoptotic capability is necessary for successful pathogenesis . The study of mechanisms by which Salmonella induces programmed cell death offers new insights into how pathogens cause disease and into general mechanisms of activation of the innate immune system.

Clin Microbiol Infect, 2003 Mar, 9(3), 234 - 8
Detection of bloodstream pathogens in a bacille Calmette-Guérin (BCG)-vaccinated pediatric population in Malawi: a pilot study; Archibald LK et al.; Children in Malawi receive bacille Calmette-Guerin (BCG) vaccination within the first 3 days of life . Thus, we hypothesized that Malawian children infected with the human immunodeficiency type 1 virus (HIV-1) might be particularly vulnerable to dissemination of the BCG Mycobacterium bovis strain with which they were vaccinated . Following informed consent by parents, we studied children admitted to a Malawi general hospital during the 1998 wet and dry seasons . Blood from cohorts of acutely ill children was cultured for bacteria, including mycobacteria, and fungi, and tested for anti-HIV-1 antibodies . It was shown that non-typhi Salmonella and Escherichia coli were the predominant bloodstream pathogens during the wet and dry seasons, and that bloodstream dissemination of the BCG M . bovis strain is uncommon in HIV-1-infected children who receive the BCG vaccine.

Rocz Panstw Zakl Hig, 2002, 53(4), 351 - 8
{Assessment of microbiological quality of minced meat designed for retail sale}; Bialasiewicz D et al.; In the years 2000-2001 eighty nine portions (445 samples) of minced meat (beef and pork, beef, pork, veal, turkey) produced by supermarkets and other meat producers from Lodz and around Lodz were examined to check if they meet the standard requirements of PN-97/A-82009 and PN-97/A-82009/A1 . The following parameters were determined according to PN-94/A-82055: the total number of microorganisms, most probable number of Escherichia coli, enumeration of Staphylococcus aureus and detection of Salmonella . In addition the presence of Listeria was determined in 25 g of examined meat . The examination showed that 36 (40.4%) portions of minced meat did not meet the requirements of standards mainly because the number of most probable number of E . coli exceeded the norm values.

Vet Clin Pathol, 1995, 24(4), 109 - 116
A review of antimicrobial peptides: defensins and related cationic peptides; Evans EW et al.; Cationic antimicrobial peptides are present throughout the plant and animal kingdoms and bear striking structural and functional similarities across species lines . They provide primitive, nonspecific means of combating a variety of bacteria, fungi, enveloped viruses, and protozoa . Some are also cytotoxic against host cells, including neoplastic cells . Cationic antimicrobial peptides may play various roles in inflammation and tissue repair . Antimicrobial peptides are found in epithelial tissues regularly exposed to microbial attack as well as in cells whose primary function is defense against potential pathogens . They constitute an important part of the nonoxidative antimicrobial arsenal of leukocytes . They are preformed and/or readily synthesized when the cells are stimulated by exposure to pathogens . They exert their effects directly by inserting into membranes of target cells and forming ion channels which increase membrane permeability; however, antimicrobial peptides can also act as opsonins to facilitate phagocytosis . Resistance to defensins is a virulence factor for organisms such as Salmonella sp . The study of cationic antimicrobial peptides is increasing our understanding of innate immunity, inflammation, and the pathogenesis of genetic diseases such as specific granule disease in humans . Therapeutic applications of antimicrobial peptides are currently under investigation.

J Mol Evol, 2003 Apr, 56(4), 498 - 508
Rates of DNA sequence evolution in experimental populations of Escherichia coli during 20,000 generations; Lenski RE et al.; We examined rates of DNA sequence evolution in 12 populations of Escherichia coli propagated in a glucose minimal medium for 20,000 generations . Previous work saw mutations mediated by mobile elements in these populations, but the extent of other genomic changes was not investigated . Four of the populations evolved defects in DNA repair and became mutators . Some 500 bp was sequenced in each of 36 genes for 50 clones, including 2 ancestral variants, 2 clones from each population at generation 10,000, and 2 from each at generation 20,000 . Ten mutations were found in total, all point mutations including mostly synonymous substitutions and nonsynonymous polymorphisms; all 10 were found in mutator populations . We compared the observed sequence evolution to predictions based on different scenarios . The number of synonymous substitutions is lower than predicted from measured mutation rates in E . coli, but the number is higher than rates based on comparing E . coli and Salmonella genomes . Extrapolating to the entire genome, these data predict about 250 synonymous substitutions on average per mutator population, but only about 3 synonymous substitutions per nonmutator population, during 20,000 generations . These data illustrate the challenge of finding sequence variation among bacterial isolates that share such a recent ancestor . However, this limited variation also provides a useful baseline for research aimed at finding the beneficial substitutions in these populations.

Bull Exp Biol Med, 2002 Dec, 134(6), 551 - 3
Perftoran as a means modulating the functional activity of liver macrophages; Kovelenov AY et al.; Experiments on mice showed that perfluorocarbon emulsion Perftoran modulated phagocytic activity of liver macrophages (evaluated by LD50 for Salmonella typhi endotoxin and the rate of elimination of Chinese ink particles from the bloodflow) . Phagocytic activity was suppressed for 3 days after injection of 10 mg/kg emulsion, but then increased above the control . Perftoran had a favorable impact on the course of experimental hepatitis in a model experiment based on hyperactivity of Kupffer cells . Perftoran virtually prevented the development of severe hepatitis after prophylactic injection and notably attenuated hepatocyte cytolysis when used as therapeutic mean.

Biochem Biophys Res Commun, 2003 Apr 4, 303(2), 458 - 62
Chemical modification of microcin J25 with diethylpyrocarbonate and carbodiimide: evidence for essential histidyl and carboxyl residues; Bellomio A et al.; In this paper we compared the antibacterial activity of native microcin J25, a peptide antibiotic, with the activities of two analogues obtained by chemical modifications . In the first analogue, the negative charge of glutamic carboxyl group was specifically blocked with an L-glycine methyl ester and in the second the histidine imidazole ring was carbethoxylated . Both analogues decreased notably its antibiotic activity against Escherichia coli and Salmonella newport, strains sensible to the native microcin J25 . The biological activity of the carbethoxylated analogue was completely recovered after treatment with hydroxylamine . The extreme importance of both polar residues could be interpreted as specific structural features indispensable for the peptide transportation into the cell, extrusion outside the cell or alternatively to inhibit the RNA-polymerase.

Indian Pediatr, 2003 Mar, 40(3), 252 - 4
Pleural effusion in complicated Salmonella paratyphi A infection; Mathur P et al.; Enteric fever can present with unusual manifestations . We observed a rare case of Salmonella paratyphi A infection in which multiple organs were involved and the organism was isolated from pleural fluid and blood . In the present era of antimicrobial drug resistance, awareness about such atypical presentations is essential to initiate a prompt treatment.

Chemosphere, 2003 Jan, 50(3), 275 - 82
Contribution of metabolites to mutagenicity during anaerobic biodegradation of fenitrothion; Matsushita T et al.; The contribution of fenitrothion and its microbial metabolites to the mutagenicity of a fenitrothion-containing solution was investigated during anaerobic biodegradation . Although a mixed culture of bacteria obtained from a paddy field degraded fenitrothion and reduced its concentration from 4.6 to 0.1 mg/l in 6 days, the indirect mutagenicity of the solution in Salmonella strain YG1029 increased . This increase was found to be partially due to amino-fenitrothion generated during the biodegradation . In addition, other unidentified metabolites contributed to the mutagenicity . In contrast, the indirect mutagenicity in strain YG1042, which was initially large because of fenitrothion, then decreased, and increased again . This increase in mutagenicity was also due to amino-fenitrothion and other unidentified metabolites . The mutagenicity in strains YG1029 and YG1042 decreased after day 6 . The greatest contribution of amino-fenitrothion to the mutagenicity was calculated to be 73% and 61% in YG1029 and YG1042 on day 3 of incubation, respectively . That of unidentified metabolites was calculated at 49% and 61% on day 20, respectively . Therefore, because not all the toxic metabolites of a compound can be identified, it is important to evaluate the toxicity of a whole solution in a bioassay such as the Ames assay rather than deducing the toxicity of the solution from the combined toxicities of known metabolites.

Proc Natl Acad Sci U S A, 2003 Apr 1, 100(7), 3677 - 82 Epub 2003 Mar 24.
Salmochelins, siderophores of Salmonella enterica and uropathogenic Escherichia coli strains, are recognized by the outer membrane receptor IroN; Hantke K et al.; Members of a family of catecholate siderophores, called salmochelins, were isolated by reversed-phase HPLC from Salmonella enterica serotype Typhimurium and structurally characterized by Fourier transform ion cyclotron resonance-MSMS and GC-MS . The tentative structure of salmochelin 1 contained two 2,3- dihydroxybenzoylserine moieties bridged by a glucose residue, bound to the serine hydroxyl group of one moiety and the carboxylate of the second moiety . Salmochelin 2 contained in addition a second glucose residue linked to a third 2,3-dihydroxybenzoylserine moiety . Salmochelins were not produced by an iroBC mutant, which indicated that the IroB protein might be responsible for the glucosyl transfer predicted by sequence similarities to known glycosyltransferases . Uptake experiments with radiolabeled (55)Fe-salmochelin and growth promotion tests with salmochelins showed that the IroN outer membrane receptor, encoded in the iroA locus of S . enterica and uropathogenic Escherichia coli strains, was the main receptor for ferric salmochelin transport.

Nucleic Acids Res, 2003 Apr 1, 31(7), 1869 - 76
A non-redundant microarray of genes for two related bacteria; Porwollik S et al.; A microarray with sequences from the annotated open reading frames (ORFs) in Salmonella enterica subspecies 1, serovar Typhimurium was supplemented with annotated chromosomal ORFs from serovar Typhi that are divergent from Typhimurium (>10% DNA sequence divergence) . This non- redundant array was used to (i) measure changes in gene copy number in DNA from actively growing versus stationary Typhi and (ii) to reveal the transcriptional response of Typhi to peroxide, a stress similar to that experienced when they are phagocytosed by macrophages . In S.enterica subspecies 1, pairs of genomes differ in the presence or absence of approximately 10% of their genes . An array twice the size of that needed to cover all ORFs for one genome could carry close homologs of all the ORFs for 10 genomes . Non-redundant DNA arrays could be constructed for any group of closely related organisms that differ by the presence and absence of a few genes.

Infect Immun, 2003 Apr, 71(4), 2258 - 61
Vector priming reduces the immunogenicity of Salmonella-based vaccines in Nramp1+/+ mice; Vindurampulle CJ et al.; The present studies in Nramp1(-/-) BALB/c and Nramp1(+/+) CBA mice question the significance of this genotype as a determinant of the level of gut colonization following oral administration of naturally attenuated or highly virulent Salmonella strains . In line with previous results in BALB/c hosts, vector priming of CBA mice with Salmonella enterica serovar Stanley was found to significantly compromise the immunogenicity of a recombinant construct expressing a foreign pilus protein.

Infect Immun, 2003 Apr, 71(4), 2247 - 52
Molecular characterization of the prototrophic Salmonella mutants defective for intraepithelial replication; Suvarnapunya AE et al.; Three MudJ prototrophs demonstrated that intracellular replication is a Salmonella virulence trait (K . Y . Leung and B . B . Finlay, Proc . Natl . Acad . Sci . USA, 88:11470-11474, 1991) . mutS and mutH are disrupted in mutants 3-11 and 12-23, and ssaQ is disrupted in mutant 17-21 . Further analysis revealed that loss of Salmonella pathogenicity island 2 function underlies the intracellular replication defect of 3-11 and 17-21.

Infect Immun, 2003 Apr, 71(4), 2182 - 91
Rapid protection of gnotobiotic pigs against experimental salmonellosis following induction of polymorphonuclear leukocytes by avirulent Salmonella enterica; Foster N et al.; Oral inoculation of 5-day-old gnotobiotic pigs with Salmonella enterica serovar Typhimurium strain F98 resulted in severe enteritis and invasive disease . Preinoculation 24 h earlier with an avirulent mutant of Salmonella enterica serovar Infantis (1326/28) completely prevented disease for up to 14 days (when the experiment was terminated) . S . enterica serovar Infantis colonized the alimentary tract well, with high bacterial counts in the intestinal lumen but with almost no invasion into the tissues . Unprotected pigs had high S . enterica serovar Typhimurium counts in the intestines, blood, and major nonintestinal organs . Recovery of this strain from the blood and major organs in S . enterica serovar Infantis-protected pigs was substantially reduced despite the fact that intestinal counts were also very high . Protection against disease thus did not involve a colonization exclusion phenomenon . Significant (P < 0.05) infiltration of monocytes/macrophages was observed in the submucosal regions of the intestines of both S . enterica serovar Infantis-protected S . enterica serovar Typhimurium-challenged pigs and unprotected S . enterica serovar Typhimurium-challenged pigs . However, only polymorphonuclear neutrophils (PMNs) were observed throughout the villus, where significant (P < 0.05) numbers infiltrated the lamina propria and the subnuclear and supranuclear regions of the epithelia, indicating that PMN induction and positioning following S . enterica serovar Infantis inoculation was consistent with rapid protection against the challenge strain . Similarly, in vitro experiments using a human fetal intestinal epithelial cell line (INT 407) demonstrated that, although significantly (P < 0.05) fewer S . enterica serovar Infantis than S . enterica serovar Typhimurium organisms invaded the monolayers, S . enterica serovar Infantis induced an NF-kappaB response and significantly (P < 0.05) raised interleukin 8 levels and transmigration of porcine PMN . The results of this study suggest that attenuated Salmonella strains can protect the immature intestine against clinical salmonellosis by PMN induction . They also demonstrate that PMN induction is not necessarily associated with clinical symptoms and/or intestinal pathology.

Infect Immun, 2003 Apr, 71(4), 2102 - 9
Salmonella infection induces a hypersecretory phenotype in human intestinal xenografts by inducing cyclooxygenase 2; Bertelsen LS et al.; Enteric Salmonella infection is accompanied by inflammation and diarrhea, and yet little is known about its effects on intestinal epithelial physiology . Since species differences limit the utility of animal tissues and cell lines lack relevant cell-cell interactions, we have used a human model of fetal intestine grown as xenografts in SCID mice . We investigated here the effects of Salmonella enterica serovar Typhimurium SL1344 on xenograft ion transport . Harvested xenografts were stripped of seromuscular layers by blunt dissection, infected with Salmonella, and mounted in Ussing chambers . Salmonella infection for 1 h increased baseline ion transport without altering tissue conductance or morphology . The increased transport was blocked by the cyclooxygenase inhibitor, indomethacin, or the specific Cox-2 inhibitor, NS-398 . Further, xenografts infected for 2 h showed increased secretory responses to the calcium-dependent agonist, carbachol, and the cyclic AMP-dependent agonists prostaglandin E(2) (PGE(2)) and forskolin, which were blocked by indomethacin . Western blot experiments revealed that infection was accompanied by increased cyclooxygenase 2 (Cox-2) expression, with no change in Cox-1 levels . Immunoassay demonstrated basolateral PGE(2) release, which was inhibited by indomethacin . Histological examination of infected xenografts illustrated that upregulated Cox-2 expression was restricted to the epithelium and that little or no invasion of the tissue by Salmonella occurred for up to 2 h . In summary, Salmonella infection rapidly increases Cox-2 expression in human intestinal tissue, accounting for increased epithelial ion transport characteristic of infectious diarrhea.

Infect Immun, 2003 Apr, 71(4), 2079 - 86
Major histocompatibility complex heterozygote superiority during coinfection; McClelland EE et al.; Genes of the major histocompatibility complex (MHC) play a critical role in immune recognition, and many alleles confer susceptibility to infectious and autoimmune diseases . How these deleterious alleles persist in populations is controversial . One hypothesis postulates that MHC heterozygote superiority emerges over multiple infections because MHC-mediated resistance is generally dominant and many allele-specific susceptibilities to pathogens will be masked by the resistant allele in heterozygotes . We tested this hypothesis by using experimental coinfections with Salmonella enterica (serovar Typhimurium C5TS) and Theiler's murine encephalomyelitis virus (TMEV) in MHC-congenic mouse strains where one haplotype was resistant to Salmonella and the other was resistant to TMEV . MHC heterozygotes were superior to both homozygotes in 7 out of 8 comparisons (P = 0.0024), and the mean standardized pathogen load of heterozygotes was reduced by 41% over that of homozygotes (P = 0.01) . In contrast, no heterozygote superiority was observed when the MHC haplotype combinations had similar susceptibility profiles to the two pathogens . This is the first experimental evidence for MHC heterozygote superiority against multiple pathogens, a mechanism that would contribute to the evolution of MHC diversity and explain the persistence of alleles conferring susceptibility to disease.

Infect Immun, 2003 Apr, 71(4), 1944 - 52
Autodisplay: development of an efficacious system for surface display of antigenic determinants in Salmonella vaccine strains; Kramer U et al.; To optimize antigen delivery by Salmonella vaccine strains, a system for surface display of antigenic determinants was established by using the autotransporter secretion pathway of gram-negative bacteria . A modular system for surface display allowed effective targeting of heterologous antigens or fragments thereof to the bacterial surface by the autotransporter domain of AIDA-I, the Escherichia coli adhesin involved in diffuse adherence . A major histocompatibility complex class II-restricted epitope, comprising amino acids 74 to 86 of the Yersinia enterocolitica heat shock protein Hsp60 (Hsp60(74-86)), was fused to the AIDA-I autotransporter domain, and the resulting fusion protein was expressed at high levels on the cell surface of E . coli and Salmonella enterica serovar Typhimurium . Colonization studies in mice vaccinated with Salmonella strains expressing AIDA-I fusion proteins demonstrated high genetic stability of the generated vaccine strain in vivo . Furthermore, a pronounced T-cell response against Yersinia Hsp60(74-86) was induced in mice vaccinated with a Salmonella vaccine strain expressing the Hsp60(74-86)-AIDA-I fusion protein . This was shown by monitoring Yersinia Hsp60-stimulated IFN-gamma secretion and proliferation of splenic T cells isolated from vaccinated mice . These results demonstrate that the surface display of antigenic determinants by the autotransporter pathway deserves special attention regarding the application in live attenuated Salmonella vaccine strains.

Infect Immun, 2003 Apr, 71(4), 1919 - 28
Contribution of the Shigella flexneri Sit, Iuc, and Feo iron acquisition systems to iron acquisition in vitro and in cultured cells; Runyen-Janecky LJ et al.; Shigella flexneri possesses multiple iron acquisition systems, including proteins involved in the synthesis and uptake of siderophores and the Feo system for ferrous iron utilization . We identified an additional S . flexneri putative iron transport gene, sitA, in a screen for S . flexneri genes that are induced in the eukaryotic intracellular environment . sitA was present in all Shigella species and in most enteroinvasive Escherichia coli strains but not in any other E . coli isolates tested . The sit locus consists of four genes encoding a potential ABC transport system . The deduced amino acid sequence of the S . flexneri sit locus was homologous to the Salmonella enterica serovar Typhimurium Sit and Yersinia pestis Yfe systems, which mediate both manganese and iron transport . The S . flexneri sit promoter was repressed by either iron or manganese, and the iron repression was partially dependent upon Fur . A sitA::cam mutation was constructed in S . flexneri . The sitA mutant showed reduced growth, relative to the wild type, in Luria broth containing an iron chelator but formed wild-type plaques on Henle cell monolayers, indicating that the sitA mutant was able to acquire iron and/or manganese in the host cell . However, mutants defective in two of these iron acquisition systems (sitA iucD, sitA feoB, and feoB iucD) formed slightly smaller plaques on Henle cell monolayers . A strain carrying mutations in sitA, feoB, and iucD did not form plaques on Henle cell monolayers.

J Antimicrob Chemother, 2003 Apr, 51(4), 1007 - 9 Epub 2003 Feb 25.
Florfenicol resistance in Salmonella enterica serovar Newport mediated by a plasmid related to R55 from Klebsiella pneumoniae; Meunier D et al.; Florfenicol resistance has emerged over the past few years in multidrug-resistant Salmonella enterica serovars Typhimurium, Agona and Paratyphi B . The floR gene encoding florfenicol resistance is chromosomally located in these serovars within a genomic island of 43 kb called SGI1 (Salmonella genomic island 1) . In the present study, we characterized florfenicol resistance in a strain of S . enterica serovar Newport isolated from a turkey in 1990 and that lacked SGI1 . Florfenicol resistance was mediated by a conjugative plasmid related to R55 from Klebsiella pneumoniae, which was characterized initially in the 1970s and harbours a gene 95% identical to floR.

Antimicrob Agents Chemother, 2003 Apr, 47(4), 1427 - 9
Integron-associated antibiotic resistance in Salmonella enterica serovar typhi from Asia; Ploy MC et al.; Eighteen of 25 isolates of Salmonella enterica serovar Typhi were multidrug resistant and contained class 1 integrons with a single cassette, dfrVII or aadA1 . The dfrVII-containing integron was likely borne on an IncHI1 plasmid . Salmonella serovar Typhi could become resistant to broad-spectrum cephalosporins by integrating cassettes, such as veb-1, a common cassette in Asia.

Antimicrob Agents Chemother, 2003 Apr, 47(4), 1297 - 300
Imipenem resistance in a Salmonella clinical strain due to plasmid-mediated class A carbapenemase KPC-2; Miriagou V et al.; A Salmonella enterica serotype Cubana isolate exhibiting resistance to most beta-lactam antibiotics, including oxyimino-cephalosporins and imipenem, was isolated from a 4-year-old boy with gastroenteritis in Maryland . beta-Lactam resistance was mediated by a conjugative plasmid that encoded KPC-2, a class A carbapenemase previously found in a Klebsiella pneumoniae isolate from the Maryland area as well . Sequence analysis of the flanking regions indicated a potential association of bla(KPC-2) with mobile structures.

J Microbiol Methods, 2003 May, 53(2), 273 - 85
Specific and selective biosensor for Salmonella and its detection in the environment; Olsen EV et al.; The specific and selective detection of Salmonella typhymurium based on the use of a polyclonal antibody immobilized by the Langmuir-Blodgett method on the surface of a quartz crystal acoustic wave device was demonstrated in liquid samples . These biosensors were selective to S . typhymurium in the presence of large concentrations of Escherichia coli O157:H7 . They were also specific to S . typhymurium since bacteria preincubated with free antibody produced no signal . Dark-field and electron microscopy showed that two different antibodies, polyvalent somatic O and flagellar H7, were immobilized on the sensor surface producing two distinct attachments of bacteria at the liquid-solid interface . The somatic O antibody exhibits a rigid, binding, while the flagellar H7 antibody forms a flexible connection allowing a large degree of freedom . When the attachment of bacteria was rigid and strong, the responses of the acoustic wave sensors correlated with changes in the mass of bacteria present at the liquid-solid interface . In contrast, when attachment was flexible, the sensor signals were inversely proportional to the additional mass of bound bacteria . This difference is probably determined by the interfacial viscoelasticity and by acoustic and electromagnetic coupling . The signals of environmentally aged sensors with either predominantly rigid or flexible positioning of bacteria were correlated with changes in mass at the liquid-solid interface . Sensors with O or H type of binding could be used for analytical purposes.

J Microbiol Methods, 2003 May, 53(2), 199 - 209
Detection of pathogenic bacteria in shellfish using multiplex PCR followed by CovaLink NH microwell plate sandwich hybridization; Lee CY et al.; Outbreak of diseases associated with consumption of raw shellfish especially oysters is a major concern to the seafood industry and public health agencies . A multiplex PCR amplification of targeted gene segments followed by DNA-DNA sandwich hybridization was optimized to detect the etiologic agents . First, a multiplex PCR amplification of hns, spvB, vvh, ctx and tl was developed enabling simultaneous detection of total Salmonella enterica serotype Typhimurium, Vibrio vulnificus, Vibrio cholerae and Vibrio parahaemolyticus from both pure cultures and seeded oysters . Amplicons were then subjected to a colorimetric CovaLink NH microwell plate sandwich hybridization using phosphorylated and biotinlylated oligonucleotide probes, the nucleotide sequences of which were located internal to the amplified DNA . The results from the hybridization with the multiplexed PCR amplified DNA exhibited a high signal/noise ratio ranging between 14.1 and 43.2 measured at 405 nm wavelength . The sensitivity of detection for each pathogen was 10(2) cells/g of oyster tissue homogenate . The results from this study showed that the combination of the multiplex PCR with a colorimetric microwell plate sandwich hybridization assay permits a specific, sensitive, and reproducible system for the detection of the microbial pathogens in shellfish, thereby improving the microbiological safety of shellfish to consumers.

Bioresour Technol, 2003 Jan, 86(2), 177 - 81
Survival of Salmonella spp . in a simulated acid-phase anaerobic digester treating sewage sludge; Fukushi K et al.; The presence of pathogenic microorganisms in municipal waste sludge may create a serious outbreak of water borne diseases if the sludge is used for agricultural purpose . An attempt to decrease the number of pathogenic microorganisms, Salmonella spp . using a simulated acid-phase anaerobic digester was tested in a laboratory-scale batch experiment . Reduction of Salmonella spp . was demonstrated in a mixture of sludge and organic acid, simulating an acid digester of a two-phase anaerobic digestion process . A high concentration of organic acid at a pH value of 5.5-6.0 prevents a decrease in Salmonella spp . concentration . Almost complete destruction of Salmonella spp . is observed within two days if the pH value is maintained below 5.5.

DNA Seq, 2002 Dec, 13(6), 333 - 41
Cloning and characterization of an iron regulated locus, iroA, in Salmonella enterica serovar Choleraesuis; Wu WS et al.; To identify genes belonging to the Ferric update regulator (Fur) regulon of Salmonella enterica serovar Choleraesuis, the Fur titration assay (FURTA) was used to screen a genomic library for Fur promoters and iron-regulated genes . Fifteen FURTA positive clones were identified from this assay . DNA sequence analysis of these clones showed that 11 out of 15 clones had a Fur binding site (Fur box), and 6 of these clones showed homology to the iron-regulated genes of S . enterica serovar Typhi and/or E . coli . One of these clones (pSC4) was homologous to the iroB gene of the iroA locus of S . enterica serovar Typhi . The iroA locus of S . enterica serovar Choleraesuis was cloned from a lambda-dash library and subjected to DNA sequencing . The complete nucleotide sequence of 9848 bp of the iroA locus of S . enterica serovar Choleraesuis consists of iroB, C, D, E and N genes, which are transcriptionally regulated by Fur . The amino acid sequence of IroB, C, D, E and N was 95%, 86, 89, 96 and 96% identity to that of S . enterica serovar Typhi . The IroN gene was homologous to the family of TonB-dependent outer membrane receptors and the putative virulence factor, IroNE . coli, of the extraintestinal pathogenic E . coli . The convalescent porcine sera contained antibodies against the three major iron-regulated outer membrane proteins of S . enterica serovar Choleraesuis . An insertional inactivation of the iroN gene of S . enterica serovar Choleraesuis by allelic exchange resulted in the loss of expression of the 78 kDa protein . However, this mutant had a similar LD50 to mice compared to the parent strain when given intraperitoneally.

Clin Infect Dis, 2003 Apr 1, 36(7), 829 - 34 Epub 2003 Mar 18.
Risk factors for primary bacteremia and endovascular infection in patients without acquired immunodeficiency syndrome who have nontyphoid salmonellosis; Hsu RB et al.; This study sought to find the risk factors for primary bacteremia, endovascular infection, and in-hospital death for patients without acquired immunodeficiency syndrome who have nontyphoid salmonellosis . From September 1995 through September 2001, 301 patients with nontyphoid salmonellosis were admitted to our hospital; of these patients, 121 had primary bacteremia, and 28 had endovascular infection . Of the 121 patients with primary bacteremia, 64 were aged >50 years, and 26 had endovascular infection . Overall, 90 patients (29.9%) had immunodeficiency . Predictors of primary bacteremia were age; presence of systemic lupus erythematosus; group B, group C, or group D Salmonella infection; and immunodeficiency . The positive predictor of endovascular infection in adult patients with primary bacteremia was group C Salmonella infection, and negative predictors were immunodeficiency and solid-organ cancer . The overall in-hospital mortality rate was 12%; for primary bacteremia, it was 24.8%; for endovascular infection, it was 14.3% . Predictors of in-hospital death were age, extraintestinal infection, and solid-organ malignancy.

Mutat Res, 2003 Apr 9, 525(1-2), 77 - 83
Mutation spectra of smoky coal combustion emissions in Salmonella reflect the TP53 and KRAS mutations in lung tumors from smoky coal-exposed individuals; Granville CA et al.; Nonsmoking women in Xuan Wei County, Yunnan Province, China who use smoky coal for cooking and heating in poorly ventilated homes have the highest lung cancer mortality rate in China, and their lung cancer is linked epidemiologically to their use of smoky coal . The emissions contain 81% organic matter, of which 43% is polycyclic aromatic hydrocarbons (PAHs) . Exposure assessment and molecular analysis of the lung tumors from nonsmoking women who use smoky coal strongly indicate that PAHs in the emissions are a primary cause of the elevated lung cancer in this population . Here we have determined the mutation spectra of an extract of smoky coal emissions in Salmonella TA98 and TA100; the extract was not mutagenic in TA104 . The extract was 8.7 x more mutagenic in TA100 with S9 than without (8.7 rev/microg versus 1.0 rev/microg) and was >3 x more mutagenic in TA100 than in TA98--consistent with a prominent role for PAHs in the mutagenicity of the extract because PAHs are generally more mutagenic in the base-substitution strain TA100 than in the frameshift strain TA98 . The extract induced only a hotspot mutation in TA98; another combustion emission, cigarette smoke condensate (CSC), also induces this single class of mutation . In TA100, the mutation spectra of the extract were not significantly different in the presence or absence of S9 and were primarily (78-86%) GC --> TA transversions . This mutation is induced to a similar extent by CSC (78%) and the PAH benzo{a}pyrene (B{a}P) (77%) . The frequency of GC --> TA transversions induced in Salmonella by the extract (78-86%) is similar to the frequency of this mutation in the TP53 (76%) and KRAS (86%) genes of lung tumors from nonsmoking women exposed to smoky coal emissions . The mutation spectra of the extract reflect the presence of PAHs in the mixture and support a role for PAHs in the induction of the mutations and tumors due to exposure to smoky coal emissions.

Vet Rec, 2003 Mar 8, 152(10), 283 - 7
Observations on Salmonella contamination of commercial laying farms before and after cleaning and disinfection; Davies R et al.; Little is known about the effectiveness of the cleaning and disinfection methods in use on commercial laying farms in Great Britain . Samples were taken from poultry house structures and equipment of five cage layer flocks, five barn egg production flocks and two free-range flocks . In the free-range houses there was a decrease in Salmonella after cleaning and disinfection, although the soil in the paddocks remained contaminated . In the barn and especially the cage layer houses, significant residual contamination remained on the surfaces of buildings and equipment . Wildlife pests were also found to be carrying Salmonella in the disinfected houses and free-range paddocks.

Med Dosw Mikrobiol, 2002, 54(4), 347 - 55
{Evaluation of usefulness for selected virulence markers for identifying pathogenic Yersinia enterocolitica strains . IV . Genes myfA and ureC}; Gierczynski R et al.; We check by polymerase chain reaction (PCR) the presence of gene ureC and myfA, encoding subunits of urease and Myf fimbriae, among clinical and food-originated strains of Yersinia to determine their usefulness as molecular virulence markers of Y . enterocolitica . The examinations were done on 130 clinical strains of Y . enterocolitica O:3/4 isolated in Poland from humans . All strains were obtained from stool and possessed the virulence plasmid pYV . In addition 40 isogenic, plasmid-cured strains were tested . The 52 strains including Y . enterocolitica (biotype 1A, 4, 2 and 1B), Y . pseudotuberculosis, Y . intermedia, Y . frederiksenii, Y . kristensenii, E . coli, Citrobatcer, Shigella and Salmonella were used as controls . The PCR assay resulted in detection of genes: ureC and myfA in genomic DNA of all 130 tested clinical strains of Y . enterocolitica pYV+, as well as in plasmid cured strains . Furthermore, ureC was found in all tested strains of Y . enterocolitica biotype A1 and in one strain of Y . intermedia and Y . kristensenii . In contrast to ureC, myfA was detected only in strains of Y . enterocolitica considered as pathogenic . Obtained results show, gene myfA seems to be the reliable virulence marker of Y . enterocolitica, whereas ureC is not recommended for identification of pathogenic strains of this species.

Med Dosw Mikrobiol, 2002, 54(4), 325 - 34
{Phage types and plasmid profiles of plasmid DNA strains of Salmonella enterica subsp . enterica ser . Enteritidis (S . Enteritidis) isolated from food poisoning outbreaks in 2001}; Cieslik A et al.; Salmonella Enteritidis strains are the most often isolated Salmonella serovar in Poland . In the present study, phage typing, antibiotic resistance testing and plasmid profile analysis, have been applied to characterise 41 Polish S . Enteritidis isolates originated from human cases of salmonellosis and from other sources . The typing phages of Ward and colleagues scheme were used to type a total of 41 S . Enteritidis strains coming from Poland . All 41 strains were typable and 5 different phage types were observed . Among 41 strains tested, both PT6 and PT21 were recognized in the 15 strains (36.6%) . Nine strains (22%) belonged to phage type 8 . The others PTs were represented by small amount of strains (PT1var and PT4) . Among all tested isolates only 4 different plasmid profiles were observed . Of the 41 strains investigated, 16 (39%) contained the 57 kb plasmid alone . The remaining 25 strains (61%) except 57 kb plasmid, possessed additional DNA particles . The probable phage type conversion of PT21 to PT1var strain, possibly connected with smaller DNA particle presence, was observed . This hypothesis needs confirmation . The real S . Enteritidis epidemiological situation in Poland should be known after introducing of systematic, annual research program.

Indian J Med Sci, 2002 Jun, 56(6), 273 - 5
Enteric fever due to Salmonella Weltevreden in a four-year-old child; Ghadage DP et al.; A four-year old child was admitted with signs and symptoms suggestive of enteric fever . Blood culture and serial stool cultures were undertaken . Weltevreden, a rare Salmonella serotype was isolated from the stool samples . The isolate was sensitive to ampicillin, cefotaxime, gentamicin, chloramphenicol and ciprofloxacin.

FEMS Immunol Med Microbiol, 2003 Apr 1, 35(3), 207 - 13
Comparison of the genome sequences of Listeria monocytogenes and Listeria innocua: clues for evolution and pathogenicity; Buchrieser C et al.; Listeria monocytogenes, an invasive opportunistic, food-borne pathogen, remains one of the leading causes of mortality from food-borne infections . The recently determined complete genome sequences of L . monocytogenes strain EGDe and of that of the closely related non-pathogenic species Listeria innocua strain CLIP11262 enhance our knowledge of the genetic basis of the virulence of L . monocytogenes and advance our understanding of the evolution of these Listeria species . Both genomes encode a high number of surface, transport and regulatory proteins . Comparison of the genome organisation revealed a perfect synteny between the two Listeria genomes . Comparison with other closely related bacteria also showed a high conservation in genome organisation among the Listeria, Staphylococcus and Bacillus group of low G+C content bacteria . Distinct G+C content of a number of strain-specific genes suggests intensive lateral gene transfer . The identification of a 55-kb locus encoding proteins with high homology to Salmonella enterica serovar Typhimurium vitamin B(12) synthesis proteins as well as those necessary for degradation of ethanolamine and propanediol further indicates acquisition of a complete metabolic pathway by horizontal gene transfer and a probable role of this locus in anaerobic growth in the host.

J Clin Immunol, 2003 Jan, 23(1), 55 - 61
Long-term follow-up and prognosis of chronic granulomatous disease in Yugoslavia: is there a role for early bone marrow transplantation?
Pasic S, Minic A, Minic P, Veljkovic D, Lilic D, Slavkovic B, Pejnovic N, Abinun M.
We report the long-term follow-up of 12 pediatric-aged patients with chronic granulomatous disease (CGD) . The mean age at the onset of infections was 5 months with a median delay in diagnosis of 2.5 years . Bacille Calmette-Guerin lymphadenitis was the most common presenting infection (6) followed by suppurative lymphadenitis (4), liver abscess (1), or Salmonella sepsis (1) . Prophylaxis with cotrimoxazole was recommended to all patients . During the mean follow-up of 10 years (range, 4-23 years) pneumonitis was the most prevalent infection (91%) followed by lymphadenitis (83%), aphtous stomatitis (58%), and liver abscesses (25%) . Seven (58%) patients developed chronic lung disease due to grossly delayed diagnosis (3) or poor compliance with antimicrobial prophylaxis (4) . Five (41%) patients died during the second decade of life of aspergillosis (3) or chronic lung disease (2) . Probability of survival into the third decade of life was estimated to be only 19% . We argue that HLA-identical bone marrow transplantation (BMT), if possible, should be attempted at early age because of significant morbidity and mortality in adolescence . BMT also should be considered in patients who suffer severe infections despite antimicrobial prophylaxis or patients with evidence of chronic lung disease . Possibility of elective BMT from unrelated donors remains to be carefully evaluated.

J Formos Med Assoc, 2002 Sep, 101(9), 665 - 8
Ceftriaxone-resistant Salmonella enterica serovar Hadar: evidence for interspecies transfer of blaCMY-2 in a Taiwanese university hospital; Yan JJ et al.; The emergence of resistance to extended-spectrum cephalosporins in salmonellae is an increasing clinical problem . We report the characteristics of a ceftriaxone-resistant Salmonella enterica serovar Hadar strain collected in 2001 from a patient with a postoperative wound infection in a university hospital in Taiwan . Resistance to extended-spectrum cephalosporins was found to be due to production of the plasmid-mediated CMY-2 AmpC beta-lactamase . To our knowledge, this is the first report of S . hadar harboring blaCMY-2 . Seven CMY-2-producing Escherichia coli isolates collected in 2000 were investigated for comparison . Conjugation experiments and plasmid analysis showed an identical plasmid carrying blaCMY-2 in both the Salmonella isolate and one E . coli isolate, suggesting the possibility that the Salmonella isolate acquired the resistance plasmid from E . coli . These findings suggest that measures are necessary to restrict antibiotic use and so prevent the spread and development of antibiotic resistance in Taiwan.

J Formos Med Assoc, 2002 Sep, 101(9), 661 - 4
Identification of Escherichia coli O157:H7 by multiplex PCR with primers specific to the hlyA, eaeA, stx1, stx2, fliC and rfb genes; Pan TM et al.; Escherichia coli O157:H7 can cause fatal diseases such as hemolytic-uremic syndrome and thrombotic thrombocytopenic purpura . The early symptoms of E . coli O157:H7 infection are similar to those of infection with other gastrointestinal bacteria, so the availability of a rapid and precise method to identify E . coli O157:H7 is important for early recognition . We report a multiplex polymerase chain reaction (PCR) with primers to detect the presence of the E . coli O157:H7 genes hlyA, which produces enterohemolysin, eaeA (intimin), stx1 (Shiga-like toxin I), stx2 (Shiga-like toxin II), fliC (flagella H-antigen), and rfb (surface O-antigen) . The technique improves specificity compared to general PCR when used with > or = 10(3) CFU/assay . Specificity was examined using 32 E . coli O157:H7 strains from the USA, Japan, Canada and Taiwan, all of which were positive for hlyA, eaeA, fliC, rfb, and stx1 and/or stx2 . Thirty-five non-O157 enterovirulent E . coli strains, two Shigella sp strains, and two Salmonella sp strains were also examined and none gave the positive gene expression results described above . This multiplex PCR was highly specific in identifying E . coli O157 and was more useful than general PCR in early clinical detection of this pathogen.

Jpn J Thorac Cardiovasc Surg, 2003 Jan, 51(1), 16 - 7
Salmonella pericarditis in a patient with primary idiopathic chylopericardium; Yoshioka H et al.; We report a case of a 40-year-old man with chylopericardium who developed purulent pericarditis caused by Salmonella enteritidis . Thoracoscopic pericardiotomy with debridement effectively controlled the pericardial infection.

J Bacteriol, 2003 Apr, 185(7), 2330 - 7
Comparative genomics of Salmonella enterica serovar Typhi strains Ty2 and CT18; Deng W et al.; We present the 4.8-Mb complete genome sequence of Salmonella enterica serovar Typhi strain Ty2, a human-specific pathogen causing typhoid fever . A comparison with the genome sequence of recently isolated S . enterica serovar Typhi strain CT18 showed that 29 of the 4,646 predicted genes in Ty2 are unique to this strain, while 84 genes are unique to CT18 . Both genomes contain more than 200 pseudogenes; 9 of these genes in CT18 are intact in Ty2, while 11 intact CT18 genes are pseudogenes in Ty2 . A half-genome interreplichore inversion in Ty2 relative to CT18 was confirmed . The two strains exhibit differences in prophages, insertion sequences, and island structures . While CT18 carries two plasmids, one conferring multiple drug resistance, Ty2 has no plasmids and is sensitive to antibiotics.

J Bacteriol, 2003 Apr, 185(7), 2131 - 42
Genomic diversification among archival strains of Salmonella enterica serovar typhimurium LT7; Liu GR et al.; To document genomic changes during long periods of storage, we analyzed Salmonella enterica serovar Typhimurium LT7, a mutator strain that was previously reported to have higher rates of mutations compared to other serovar Typhimurium strains such as LT2 . Upon plating directly from sealed agar stabs that had been stocked at room temperature for up to four decades, many auxotrophic mutants derived from LT7 gave rise to colonies of different sizes . Restreaking from single colonies consistently yielded colonies of diverse sizes even when we repeated single-colony isolation nine times . Colonies from the first plating had diverse genomic changes among and even within individual vials, including translocations, inversions, duplications, and point mutations, which were detected by rare-cutting endonuclease analysis with pulsed-field gel electrophoresis . Interestingly, even though the colony size kept diversifying, all descendents of the same single colonies from the first plating had the same sets of detected genomic changes . We did not detect any colony size or genome structure diversification in serovar Typhimurium LT7 stocked at -70 degrees C or in serovar Typhimurium LT2 stocked either at -70 degrees C or at room temperature . These results suggest that, although colony size diversification occurred during rapid growth, all detected genomic changes took place during the storage at room temperature and were carried over to their descendents without further changes during rapid growth in rich medium . We constructed a genomic cleavage map on the LT7 strain that had been stocked at -70 degrees C and located all of the detected genomic changes on the map . We speculated on the significance of mutators for survival and evolution under environmentally stressed conditions.

Emerg Infect Dis, 2003 Mar, 9(3), 323 - 8
Emergence of ceftriaxone-resistant Salmonella isolates and rapid spread of plasmid-encoded CMY-2-like cephalosporinase, Taiwan; Yan JJ et al.; Of 384 Salmonella isolates collected from 1997 to 2000 in a university hospital in Taiwan, six ceftriaxone-resistant isolates of Salmonella enterica serovar Typhimurium were found in two patients in 2000 . The resistance determinants were on conjugative plasmids that encoded a CMY-2-like cephalosporinase . During the study period, the proportion of CMY-2-like enzyme producers among Escherichia coli increased rapidly from 0.2% in early 1999 to >4.0% in late 2000 . Klebsiella pneumoniae isolates producing a CMY-2-like beta-lactamase did not emerge until 2000 . The presence of bla(CMY)-containing plasmids with an identical restriction pattern from Salmonella, E . coli, and K . pneumoniae isolates was found, which suggests interspecies spread and horizontal transfer of the resistance determinant . Various nosocomial and community-acquired infections were associated with the CMY-2-like enzyme producers . Our study suggests that the spread of plasmid-mediated CMY-2-like beta-lactamases is an emerging threat to hospitalized patients and the public in Taiwan.

East Afr Med J, 2002 Jun, 79(6), 317 - 22
Mycoplasma pneumoniae in children with pneumonia at Mbagathi District Hospital, Nairobi; Bii CC et al.; OBJECTIVE: To determine the prevalence of mycoplasma pneumoniae in nasopharyngeal aspirates of children under five years of age suffering from pneumonia . DESIGN: Cross-sectional survey . METHODS: Two primer sets targeting the genes coding for adhesion protein and 16S rRNA were used in PCR and M . pneumoniae specific antibodies were detected using commercial article agglutination kit . Microbiological investigations to isolate common acute respiratory infectious pathogens were also carried out . RESULTS: M . pneumoniae was detected in nasopharyngeal aspirates of 33.7% of the cases by PCR while serology was positive in only 4.1% . M . pneumoniae alone (single detection) was detected in 25% of the cases while 75% occurred with other acute respiratory infectious (ARI) pathogens . However, the results did not correlate with clinical outcome or the severity of pneumonia . No significant aetiology was found in 28% of the cases investigated, however microbiological investigations by culture revealed the presence of other aetiological agents as follows: Streptococcus pneumoniae (26%), Klebsiella pneumoniae (1%), Staphylococcus aureus (3%), E . coli (2%), parainfluenza viruses (5%), Salmonella(1%), adenovirus (4%), RSV (22%) and Candida spp(13%), Mycoplasma pneumoniae was more prevalent in children aged between six months and three years . Cases of M . pneumoniae PCR positive and S . pneumoniae exhibited similar seasonal distribution with peaks in May and September . However, there was no relationship between M . pneumoniae PCR positive and the severity of pneumonia . CONCLUSION: More investigation is required to establish the significance of atypical pathogens in respiratory infections in Kenya.

J Biol Chem, 2003 Jun 6, 278(23), 20874 - 81 Epub 2003 Mar 17.
High resolution x-ray structure of tyvelose epimerase from Salmonella typhi; Koropatkin NM et al.; Tyvelose epimerase catalyzes the last step in the biosynthesis of tyvelose by converting CDP-d-paratose to CDP-d-tyvelose . This unusual 3,6-dideoxyhexose occurs in the O-antigens of some types of Gram-negative bacteria . Here we describe the cloning, protein purification, and high-resolution x-ray crystallographic analysis of tyvelose epimerase from Salmonella typhi complexed with CDP . The enzyme from S . typhi is a homotetramer with each subunit containing 339 amino acid residues and a tightly bound NAD+ cofactor . The quaternary structure of the enzyme displays 222 symmetry and can be aptly described as a dimer of dimers . Each subunit folds into two distinct lobes: the N-terminal motif responsible for NAD+ binding and the C-terminal region that harbors the binding site for CDP . The analysis described here demonstrates that tyvelose epimerase belongs to the short-chain dehydrogenase/reductase superfamily of enzymes . Indeed, its active site is reminiscent to that observed for UDP-galactose 4-epimerase, an enzyme that plays a key role in galactose metabolism . Unlike UDP-galactose 4-epimerase where the conversion of configuration occurs about C-4 of the UDP-glucose or UDP-galactose substrates, in the reaction catalyzed by tyvelose epimerase, the inversion of stereochemistry occurs at C-2 . On the basis of the observed binding mode for CDP, it is possible to predict the manner in which the substrate, CDP-paratose, and the product, CDP-tyvelose, might be accommodated within the active site of tyvelose epimerase.

Lett Appl Microbiol, 2003, 36(4), 217 - 21
Evaluation of selective and non-selective enrichment PCR procedures for Salmonella detection; Oliveira SD et al.; AIMS: To compare PCR combined with enrichment media with the standard microbiological techniques (SMT) and to determine the most sensitive method for the detection of Salmonella and the identification of Salm . typhimurium (ST), Salm . enteritidis (SE), Salm . gallinarum (SG) and Salm . pullorum (SP) . METHODS AND RESULTS: We analysed 87 samples from poultry using PCR and SMT, PCR being performed from non-selective (NS) and Rappaport-Vassiliadis (RV) media . PCR-NS was less sensitive than PCR-RV and SMT for the detection and identification of Salmonella . PCR-RV detected more positive samples of Salmonella sp . than SMT but both these methods showed similar sensitivity regarding the identification of Salmonella serovars . CONCLUSIONS: PCR-RV was more sensitive and decreased the time necessary to detect and identify Salmonella . SIGNIFICANCE AND IMPACT OF THE STUDY: PCR-RV is a powerful tool for the rapid and accurate detection and identification of Salmonella and can be implemented in diagnostic and food analysis laboratories.

J Food Prot, 2003 Mar, 66(3), 490 - 2
Comparison of three commercial competitive-exclusion products for controlling Salmonella colonization of broilers in Brazil; Ferreira AJ et al.; In this study, a new competitive-exclusion (CE) product, Mucosal Starter Culture (MSC), was compared with two other CE products (Aviguard and Avifree) commercially available in Brazil to evaluate their ability to protect newly hatched chicks against colonization by a strain of Salmonella Kedougou . This study was based on a previously published and recommended method for such products . Separate groups of the chicks were dosed orally with the respective treatment materials and challenged 24 h later, and their ceca were examined for Salmonella 5 days after challenge . Under the test conditions, only MSC and Aviguard gave statistically significant (P < 0.05) protection to the chicks, but the MSC treatment yielded the lowest mean level of cecal carriage and the smallest proportion of Salmonella-positive birds.

J Food Prot, 2003 Mar, 66(3), 446 - 50
Recovery of Salmonella from retail broilers by a whole-carcass enrichment procedure; Simmons M et al.; Fresh whole broiler carcasses were purchased from grocery stores over a 20-week period . Carcasses were selected on the basis of their having intact packages and unique U.S . Department of Agriculture (USDA) plant numbers and sell-by dates, such that each bird represented a single processing plant-processing day combination . Carcasses were tested for Salmonella with a rinse aliquot obtained after whole-bird incubation in the rinse media for 24 h . On the basis of the number of unique processing plants (USDA plant numbers) and expiration dates involved, the number of birds available each week ranged from 6 to 17 . Over the 20-week period, 251 independent carcasses from 14 processing plants were tested . The percentages of carcasses testing positive for Salmonella ranged from 0 (for 1 week) to >60% (for 3 weeks) . For only 4 of the 20 weeks was an incidence of Salmonella-positive carcasses of <20% found . For the entire 20-week study, 85 (33.9%) of the 251 carcasses tested were found to be Salmonella positive . For those processing plants from which >10 carcasses were obtained, the percentages of carcasses testing positive for Salmonella ranged from <20 (two plants) to >40% (four plants) . These results indicate that a whole-carcass enrichment may be more sensitive for the detection of Salmonella-positive carcasses than the traditional whole-carcass rinse followed by immediate testing of a subsample aliquot when small numbers of Salmonella are expected.

J Food Prot, 2003 Mar, 66(3), 396 - 402
Effects of acid adaptation and modified marinades on survival of postdrying Salmonella contamination on beef jerky during storage; Calicioglu M et al.; This study was undertaken to evaluate the survival of acid-adapted and nonadapted Salmonella cultures inoculated after drying on beef jerky that had been treated with marinades before drying at 60 degrees C for 10 h . Beef slices were (i) not treated prior to refrigeration at 4 degrees C for 24 h (control {C}); (ii) marinated with traditional marinade (TM), (iii) marinated with TM modified with 1.2% sodium lactate, 9% acetic acid, and 68% soy sauce containing 5% ethanol (MM) at twice the amount used in the TM treatment; (iv) dipped into 5% acetic acid and then marinated with TM (AATM); and (v) dipped into 1% Tween 20, then dipped into 5% acetic acid, and then marinated with TM (TWTM); after each treatment, meat slices were refrigerated at 4 degrees C for 24 h prior to drying . Dried slices were inoculated with acid-adapted or nonadapted Salmonella (ca . 5.7 log CFU/cm2) prior to aerobic storage at 25 degrees C for 60 days . Tryptic soy agar with 0.1% pyruvate, as well as xylose-lysine-tergitol 4 (XLT4) agar, was used to determine survivor counts . Bacterial decreases achieved with the different treatments were found to be in the following order: TWTM (5.4 to 6.3 log units) > or = AATM > or = MM > C > or = TM (2.9 to 5.1 log units) . Acid-adapted Salmonella decreased faster than nonadapted Salmonella for all treatments . Bacterial populations decreased to below the detection limit (-0.4 log CFU/cm2) in as few as 14 days or remained detectable by direct plating after 60 days of storage, depending on acid adaptation, treatment, and agar media . The results of this study indicate that the modified marinades used in jerky processing and the low water activity of the dried product provide antimicrobial effects against possible postprocessing contamination with Salmonella, while the preparation of cultures under acid-adaptation conditions did not increase Salmonella survival during storage and may have reduced it.

Int J Med Microbiol, 2003 Feb, 292(7-8), 477 - 86
Subtyping of pathogenic Escherichia coli strains using flagellar (H)-antigens: serotyping versus fliC polymorphisms; Prager R et al.; Serotyping of O- and H-antigens is regarded as the gold standard in classification of E . coli for taxonomic and epidemiological purposes similar to the Kaufmann-White scheme for Salmonella enterica . Molecular methods to replace or to support the serotyping have been applied recently . Using the molecular polymorphism of the flagella (H-antigen) gene fliC, more than 220 E . coli strains derived from the E . coli reference collection for O- and H-antigens (The International Escherichia and Klebsiella Centre (WHO)) and from clinical origins have been characterised and a reproducible and clear cut classification with very good correlation to serotyping was found . Only some of the H-antigens have revealed multiple fliC classes and vice versa only rarely some of the fliC classes belong to various H-antigen groups . Since also H-antigen-negative and H-antigen non-typeable strains subjected to fliC classification could be typed properly, it is recommended here to use this rapid approach to classify E . coli under routine conditions rather than using classical serotyping . However, scrotyping--in particular using hyperimmune rabbit sera--will remain the gold standard and the task of Reference Centres only, e.g . for defining novel H-antigen types.

Risk Anal, 2003 Feb, 23(1), 215 - 28
Impact of microbial ecology of meat and poultry products on predictions from exposure assessment scenarios for refrigerated storage; Coleman ME et al.; A novel extension of traditional growth models for exposure assessment of food-borne microbial pathogens was developed to address the complex interactions of competing microbial populations in foods . Scenarios were designed for baseline refrigeration and mild abuse of servings of chicken broiler and ground beef Our approach employed high-quality data for microbiology of foods at production, refrigerated storage temperatures, and growth kinetics of microbial populations in culture media . Simple parallel models were developed for exponential growth of multiple pathogens and the abundant and ubiquitous nonpathogenic indigenous microbiota . Monte Carlo simulations were run for unconstrained growth and growth with the density-dependent constraint based on the "Jameson effect," inhibition of pathogen growth when the indigenous microbiota reached 10(9) counts per serving . The modes for unconstrained growth of the indigenous microbiota were 10(8), 10(10), and 10(11) counts per serving for chicken broilers, and 10(7), 10(9) and 10(11) counts per serving for ground beef at respective sites for backroom, meat case, and home refrigeration . Contamination rates and likelihoods of reaching temperatures supporting growth of the pathogens in the baseline refrigeration scenario were rare events . The unconstrained exponential growth models appeared to overestimate L . monocytogenes growth maxima for the baseline refrigeration scenario by 1500-7233% (10(6)-10(7) counts/serving) when the inhibitory effects of the indigenous microbiota are ignored . The extreme tails of the distributions for the constrained models appeared to overestimate growth maxima 110% (10(4)-10(5) counts/serving) for Salmonella spp . and 108% (6 x 10(3) counts/serving) for E . coli O157:H7 relative to the extremes of the unconstrained models . The approach of incorporating parallel models for pathogens and the indigenous microbiota into exposure assessment modeling motivates the design of validation studies to test the modeling assumptions, consistent with the analytical-deliberative process of risk analysis.

Risk Anal, 2003 Feb, 23(1), 199 - 213
Growth and heat resistance kinetic variation among various isolates of Salmonella and its application to risk assessment; Juneja VK et al.; The abilities of cells of a particular type of bacteria to leave lag phase and begin the process of dividing or surviving heat treatment can depend on the serotypes or strains of the bacteria . This article reports an investigation of serotype-specific differences in growth and heat resistance kinetics of clinical and food isolates of Salmonella . Growth kinetics at 19 degrees C and 37 degrees C were examined in brain heart infusion broth and heat resistance kinetics for 60 degrees C were examined in beef gravy using a submerged coil heating apparatus . Estimates of the parameters of the growth curves suggests a small between-serotype variance of the growth kinetics . However, for inactivation, the results suggest a significant between-serotype effect on the asymptotic D-values, with an estimated between-serotype CV of about 20% . In microbial risk assessment, predictive microbiology is used to estimate growth and inactivation of pathogens . Often the data used for estimating the growth or inactivation kinetics are based on measurements on a cocktail--a mixture of approximately equal proportions of several serotypes or strains of the pathogen being studied . The expected growth or inactivation rates derived from data using cocktails are biased, reflecting the characteristics of the fastest growing or most heat resistant serotype of the cocktail . In this article, an adjustment to decrease this possible bias in a risk assessment is offered . The article also presents discussion of the effect on estimating growth when stochastic assumptions are incorporated in the model . In particular, equations describing the variation of relative growth are derived, accounting for the stochastic variations of the division of cells . For small numbers of cells, the expected value of the relative growth is not an appropriate "representative" value for actual relative growths that might occur.

Indian J Exp Biol, 2002 Mar, 40(3), 296 - 303
Evaluation of guinea pig model for experimental Salmonella serovar Abortusequi infection in reference to infertility; Singh BR et al.; The present study conclusively revealed the role for Salmonella enterica subspecies enterica serovar Abortusequi in conception failure . None of the 12 guinea pigs conceived when orally exposed to sublethal dose of the pathogen during breeding, while 66.67% of animals in control group were found pregnant during same period of observation under similar conditions . Salmonella carrier animals also had drastic reduction in conception rate (16.67%) . During mid pregnancy, S . Abortusequi exposure to guinea pigs through intravaginal, intramuscular and subcutaneous routes induced fetal death followed by resorption . While 2 out of 6 orally inoculated and 3 out of 6 intraperitonially inoculated guinea pigs aborted, in rest of the animals fetal death was followed by meceration and resorption . It was interesting to note that S . Abortusequi could not persist longer than a week in males while in pregnant females it could be detected for >10 weeks after inoculation . In late pregnancy, most of the exposed animals aborted and non aborting animals though had normal parturition, survival rate of their babies was nearly zero in comparison to the control group . The study revealed role for S . Abortusequi in impairing conception, abortion, early fetal deaths, fetal meceration and resorption . Further studies are required to identify factors responsible for increased susceptibility of females particularly during pregnancy.

Environ Toxicol, 2003 Apr, 18(2), 69 - 77
Genotoxicity of water extracts from the River Yamuna at Mathura, India; Aleem A et al.; Water samples were collected from the River Yamuna at Mathura, India, and concentrated by using XAD resins (Amberlite XAD-4 and XAD-8) and liquid-liquid extraction procedures . The genotoxicities of the extracted water samples were evaluated by the Ames Salmonella/mammalian microsome test, DNA repair of defective mutants, and bacteriophage lambda systems . The results of the Salmonella test demonstrated that the XAD-concentrated water samples had maximum mutagenicity with the TA98 strain, both with and without metabolic activation . The XAD-concentrated water samples collected in the summer showed maximum mutagenic responses compared with those collected in other seasons, whereas the liquid-liquid extracted samples exhibited maximum mutagenic activity during the postmonsoon season . The damage brought about during DNA repair of defective mutants in the presence of XAD-concentrated water samples was found to be remarkably high compared with the liquid-liquid extracted water samples at a dose level of 20 microL/mL of culture . All the mutants invariably exhibited significant decline in their colony-forming units compared with their isogenic wild-type counterparts . Survival was decreased by 86.7% and 65.1% in the polA(-) strain after 6 h of treatment with XAD-concentrated and liquid-liquid extracted water samples, respectively . A significant decrease in the survival of bacteriophage lambda was also observed when treated with test samples . The damage was more pronounced in lexA mutants when the phage was treated with XAD-concentrated samples . The recA, lexA, and polA mutants of E . coli K-12 were found to be sensitive to the test samples, suggesting damage to the DNA of exposed cells as well as to the role of recA(+), lexA(+), and polA(+) genes in coping with the hazardous effect of the pollutants . The results demonstrated substantial genotoxicity and mutagenicity in the water samples tested .

Environ Health Perspect, 2002 Dec, 110 Suppl 6, 985 - 8
Toxicological evaluation of complex mixtures by pattern recognition: correlating chemical fingerprints to mutagenicity; Eide I et al.; We describe the use of pattern recognition and multivariate regression in the assessment of complex mixtures by correlating chemical fingerprints to the mutagenicity of the mixtures . Mixtures were 20 organic extracts of exhaust particles, each containing 102-170 individual compounds such as polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, oxy-PAHs, and saturated hydrocarbons . Mixtures were characterized by full-scan GC-MS (gas chromatography-mass spectrometry) . Data were resolved into peaks and spectra for individual compounds by an automated curve resolution procedure . Resolved chromatograms were integrated, resulting in a predictor matrix that was used as input to a principal component analysis to evaluate similarities between mixtures (i.e., classification) . Furthermore, partial least-squares projections to latent structures were used to correlate the GC-MS data to mutagenicity, as measured in the Ames Salmonella assay (i.e., calibration) . The best model (high r2 and Q2) identifies the variables that co-vary with the observed mutagenicity . These variables may subsequently be identified in more detail . Furthermore, the regression model can be used to predict mutagenicity from GC-MS chromatograms of other organic extracts . We emphasize that both chemical fingerprints as well as detailed data on composition can be used in pattern recognition.

J Comp Pathol, 2003 Feb-Apr, 128(2-3), 119 - 26
Interactions of Salmonella enterica subsp . enterica serovar Muenchen with intestinal explants of the turtle Trachemys scripta scripta; Pasmans F et al.; Salmonella infections in reptiles, in contrast to those in birds and mammals, are limited to the intestinal tract . In this study, interactions of a strain of Salmonella enterica subsp . enterica serovar Muenchen (SEEM) with intestinal explants of the turtle Trachemys scripta scripta were examined by scanning electron microscopy (SEM) . Adhesion and invasion in the chelonian intestinal explants at 30 degrees C and 37 degrees C were evaluated quantitatively . For purposes of comparison, the invasive capacity of SEEM in the continuous avian epithelial cell line DIV-1 at 30 degrees C and 37 degrees C was determined . Small numbers of M-like cells were found in the ileum of the turtles . The bacteria adhered mainly to the mucus of the intestinal explants . Only small numbers of salmonellae were associated with epithelial cells . Higher numbers of bacteria adhered at 30 degrees C than at 37 degrees C . Epithelial damage, embedding of bacteria in the epithelial surface and a ruffling-like process were noted only at 37 degrees C . Minimal numbers of salmonellae invaded the explants at 30 degrees C and 37 degrees C . Invasion of DIV-1 cells was greater at 37 degrees C than at 30 degrees C . The study suggested that the intestinal mucous layer provides an important site of colonization for salmonellae in the chelonian host and protects the underlying epithelial cells.

J Infect, 2003 Feb, 46(2), 142 - 3
Anterior chest wall abscess caused by Salmonella enteritidis in a healthy adult; Gupta SK et al.; We report a case of anterior chest wall abscess in an immunocompetent adult by Salmonella enteritidis, whose food was contaminated by bird droppings . The patient did not have any gastrointestinal symptoms . Surgical excision followed by antibiotics (cefuroxime and ciprofloxacin) successfully treated the condition . To our knowledge, this is the first reported case of anterior chest wall abscess caused by S . enteritidis in an immunocompetent adult without any preceding gastrointestinal symptoms . We feel that the contamination of his food with the bird droppings was a risk factor.

J Infect, 2003 Feb, 46(2), 111 - 9
Monocytic activation of protein tyrosine kinase, protein kinase A and protein kinase C induced by porins isolated from Salmonella enterica serovar Typhimurium; Galdiero M et al.; OBJECTIVES: In the present study a monocytic cell line, U937, was used to investigate the possible involvement of protein tyrosine kinases (NT-PTKs), protein kinase A (PKA) and protein kinase C (PKC) in cell signaling pathways following Salmonella enterica serovar Typhimurium porin stimulation . METHODS: Different concentrations of porins and lipopolysaccharide (LPS) were analysed to evaluate changes in PTK activity by a non radioactive tyrosine kinase assay and in PKA and PKC phosphorylation by Western blotting analysis . The inhibitors of PTK, PKA and PKC activation used, were: 3,4-dihydroxybenzylidene-malononitrile (tyrphostin 23), inhibitor of epidermal growth factor (EGF) receptor tyrosine kinase activity; dihychloride (H-89), a selective inhibitor of PKA which is useful to discriminate between the effects of PKC and PKA; diacylglycerol kinase inhibitor II (R59949), which is useful for elucidating roles of PKC; calphostin C, a specific inhibitor of PKC . RESULTS: Porins of the outer membrane of the ST were isolated to be used as a stimulus in the performed experiments . Following porin treatment, a dose-dependent increase in PTK, PKA and PKC activation was observed . U937 monocytes pretreated with inhibitors induced an evident decrease in PTK activity and PKA and PKC phosphorylation pattern in porin stimulated monocytes . CONCLUSIONS: Our data support the important role played by NT-PTK, PKA and PKC in transducing the activating signal in macrophages stimulated with porins through the activation of the mitogen-activated protein kinase (MAPK) pathway that participate in the regulation of gene expression.

Genet Sel Evol, 2003 Mar-Apr, 35(2), 199 - 217
Genetic parameters for resistance to the Salmonella abortusovis vaccinal strain Rv6 in sheep; Moreno CR et al.; An experimental population (1216 lambs from 30 sires) of the Inra401 sheep was created in an Inra flock to allow QTL detection for susceptibility to Salmonella infection, wool and carcass traits . The Inra401 is a sheep composite line developed from two breeds: Berrichon du Cher and Romanov . At 113 days of age on average, the lambs were inoculated intravenously with 10(8) Salmonella abortusovis Rv6 (vaccinal strain) . They were slaughtered 10 days after the inoculation . Several traits were measured at inoculation and/or slaughtering to estimate the genetic resistance of the lambs to Salmonella infection: specific IgM and IgG1 antibody titres, body weight loss, spleen and pre-scapular node weights and counts of viable Salmonella persisting in these organs . This paper presents a quantitative analysis of the genetic variability of the traits related to salmonellosis susceptibility . The heritabilities of the traits varied between 0.10 and 0.64 (significantly different from zero) . Thus, in sheep as well as in other species, the determinism of resistance to Salmonella infection is under genetic control . Moreover, the correlations between the traits are in agreement with the known immune mechanisms . The genetic variability observed should help QTL detection.

Euro Surveill, 2003 Feb, 8(2), 46 - 50
The Salm-gene project - a European collaboration for DNA fingerprinting for; Peters TM et al.; An external quality assessment of PFGE method to discriminate between salmonella serotypes and lysotypes was carried out by the Salm-Gene project in Europe . A set of 16 strains of S . Enteritidis was sent to 9 national salmonella reference laboratories . By using a harmonised protocol, the PFGE profiles produced were comparable between each centre . In most cases, there was at least 90% similarity between isolates tested in the different European laboratories and there was usually >95% similarity . This suggests that PFGE analyses are reproducible and therefore can be used as a valuable investigation tool combined with epidemiological data.

Euro Surveill, 2003 Feb, 8(2), 41 - 5
Antimicrobial drug resistance in isolates of Salmonella enterica from cases of salmonellosis in humans in Europe in 2000: results of international multi-centre surveillance; Threlfall EJ et al.; The Enter-net surveillance system received results of antimicrobial sensitivity tests for isolates from over 27 000 cases of human salmonellosis in 2000 in 10 European countries . Almost 40% of isolates were resistant to at least one antimicrobial, with 18% multiresistant . Resistance to ampicillin, streptomycin, sulphonamides and tetracyclines was common, with over 20% of isolates resistant to at least one of these antimicrobials . Clinical resistance to ciprofloxacin was rare, with only 0.5% of isolates exhibiting such resistance (MIC >1.0 mg/l) . Resistance to nalidixic acid coupled with a decreased susceptibility to ciprofloxacin (MIC 0.25-1.0 mg/l) was more common, with 14% of isolates showing these properties . Resistance to third-generation cephalosporins was rare with only 0.6% of isolates resistant to cefotaxime . In all countries multiple resistance was most common in Salmonella enterica serotype Typhimurium, with 51% of isolates multiresistant in total . In England and Wales multiple resistance was also prevalent in S . Virchow and S . Hadar, whereas in other countries multiple resistance was common in serotypes such as S . Blockley.

Euro Surveill, 2003 Feb, 8(2), 35 - 40
Investigation of human infections with Salmonella enterica serovar Java in Scotland and possible association with imported poultry; Brown DJ et al.; PFGE analysis of S . Java strains (29 from humans, 30 from poultry meat) showed two major clusters . All isolates from poultry imported from the Netherlands belonged to Cluster A, which also comprised 10 human isolates . Thirty-one of the 37 isolates in this cluster had an identical JavX1 pattern, similar to the X8 profile of a particular S . Java clone predominant in poultry production in several European countries . Cluster B comprised 19 human isolates and two poultry isolates of unknown origin . These results combined with epidemiological data and information on the origins of poultry meat strongly suggested that imported poultry meat is an important source of Java infections in humans in Scotland.

Euro Surveill, 2003 Feb, 8(2), 31 - 5
Explosive increase of Salmonella Java in poultry in the Netherlands: consequences for public health; van Pelt W et al.; In the Netherlands Salmonella Paratyphi B variant Java increased in poultry from less than 2% of all isolates before 1996 to 60% in 2002 . Despite exposure to contaminated meat is high, human patients with Java infection are rare (0.3% of all isolates) . However, 50% of the human isolates showed PFGE profiles identical to the poultry clone . Resistance to flumequin in S . Java increased from 3% between 1996-2000 to 19% in 2001, and 39% in 2002, while that of other serotypes in poultry remained at about 7% . S . Java is also fast becoming less sensitive to ciprofloxacin.

Euro Surveill, 2000 Nov, 5(11), 123 - 126
Salmonella enterica serotype Oranienburg infections associated with consumption of locally produced Tyrolean cheese; Allerberger F et al.; Sixteen culture confirmed cases of enteric infection with Salmonella enterica serotype Oranienburg were detected between August 10 and September 29 1999 in Tyrol (Austria) . Ten of them suffered bloody diarrhoea and six were asymptomatic carriers . Intervie

Euro Surveill, 2000 Dec, 5(12), 129 - 132
Surveillance of antimicrobial resistance in Denmark; Monnet DL et al.; Recent data of the Danish Integrated Antimicrobial Resistance Monitoring and Research Programme (DANMAP) show that, in Denmark, resistance levels among Salmonella enterica are modest and that resistance in Escherichia coli isolates causing disease in anim

Euro Surveill, 2001 Jul, 6(7), 117 - 20
Evolution of antibiotic resistance of non-typhoidal salmonellae in Greece during 1990-97; Velonakis EN et al.; Susceptibility to 15 antibiotics was determined in 1548 non-typhoidal salmonella strains isolated in Greece from l990 to l997 . The overall prevalence of resistance of both Salmonella enterica serotype Enteritidis and Salmonella enterica serotype Typhimurium increased during the first years of the study . A decrease was observed from 1996, especially for S . Enteritidis, which showed the highest overall antibiotic resistance . S . Typhimurium was the serotype with the highest multiresistance to antibiotics . The rest of the serotypes had very low resistance prevalence compared with both S . Enteritidis and Typhimurium serotypes.

Euro Surveill, 1999 Feb, 4(2), 24 - 26
An outbreak of Salmonella enteritidis infection associated with iced cake; D Argenio P et al.; Several people developed severe symptoms of gastroenteritis after attending a first holy communion banquet in Benevento, a town of 60 000 inhabitants in southern Italy . About 60 people had attended the banquet, held on 14 June 1998, between 1400 and 1800

Euro Surveill, 1999 Apr, 4(4), 47 - 48
An outbreak of Salmonella enteritidis food poisoning from a commercially produced cheese; Panico MG et al.; Nine suspected cases of food poisoning were reported from three hospitals to the epidemiology and prevention service (Servizio di Epidemiologia e Prevenzione - SEP) of the local health authority in Naples district (Azienda Sanitaria Locale, ASL NA 4) betw

Euro Surveill . 1999 May;4(5):56.
Salmonella enteritidis in Western Europe 1995-98 - a surveillance report from Enter-net; Fisher IS; A decline in the incidence of Salmonella enteritidis infections in western Europe was identified by the Salm-Net (forerunner of Enter-net) salmonella database between 1993 and 1995, when the numbers of S . enteritidis isolates fell from 37 647 to 31 482 . T

Euro Surveill, 1999 May, 4(5), 56 - 58
Emergence of multidrug resistant Salmonella thyphimurium DT 104 in the Czech Republic; Karpiskova R et al.; The Czech Republic is a country in central Europe with a population of about 10 million inhabitants . Salmonellosis is the most commonly reported infectious intestinal disease . Until 1989 about 10 000 cases were reported each year, and similar numbers of S

Euro Surveill . 1999 May;4(5):51.
Surveillance of salmonella: achievements and future directions; Van Pelt W; This special issue of Eurosurveillance focuses on progress of the Enter-net network in the surveillance and management of outbreaks of human salmonellosis in Europe . This network has established a frequently updated international database and collaboratio

Euro Surveill, 1999 Jun, 4(6), 72 - 75
Outbreak of Salmonella gastroenteritis among attendees of a restaurant opening in Grece, June 1998; Hadjichristodoulou C et al.; Until recently the system for reporting infectious diseases in Greece was inadequate, but a new laboratory reporting system was introduced in 1998, in which collaborating laboratories throughout Greece report each week by e-mail or fax using standard form

Euro Surveill, 1999 Sep, 4(9), 97 - 98
Outbreak of Salmonella enteritis bongori 48:z35:- in Sicily; Nastasi A et al.; Salmonella bongori 48:z 35 :- was first isolated from a lizard in Chad in 1966 and was classified as a biochemically atypical strain of the subgenus I of Kauffmann . Successively, some additional strains with different antigenic formulas but similar bioche

Euro Surveill, 2000 Jul, 5(7), 84 - 86
Endemic presence of Salmonella enterica serotype Cerro in southern Italy; Mammina C et al.; Molecular typing of salmonella strains isolated between 1997 and 1999 in southern Italy and carried out by the Southern Italy Centre for Enteric Pathogens, has shown a high frequency of Salmonella enterica serotype Cerro . This serotype is extremely rare i

Euro Surveill, 1997 Jan, 2(1), 6 - 7
Outbreak of Salmonella enteritidis phage type 1 infection in British tourists visiting Mallorca, June 1996; Wall P et al.; Three British tourists became ill while on holiday in the same hotel in Alcudia, Mallorca from 11 to 25 June 1996; Salmonella enteritidisinfections were diagnosed upon their return to England . An environmental health officer informed the Gastrointestinal

Euro Surveill, 1997 Jan, 2(1), 4 - 6
Salmonella enteritidis and S . typhimurium in Western Europe for 1993-1995: a surveillance report from Salm-Net; Fisher IS; Surveillance has been defined as the ongoing systematic collection, collation and analysis of data and the prompt dissemination of the resulting information to those who need to know so that an action can result . This is achieved in two ways . Firstly, i

Euro Surveill, 1997 Mar, 2(3), 22 - 24
Preliminary report of an international outbreak of Salmonella anatum infection linked to an infant formula milk; Investigation Internationale : Belgique France Royaume-Uni Et Le Reseau Salm-Net / International Investigation : Belgium United Kingdom France And The Salm-Net Network; The number of isolates of Salmonella anatum from infants (aged 1 to 11 months) in England and Wales was higher than expected in November and December 1996 and early January . The Public Health Laboratory Service (PHLS) Laboratory of Enteric Pathogens (LEP)

Euro Surveill, 1997 Mar, 2(3), 19 - 20
Surveillance of antibiotic resistance in Salmonella; Brisabois A et al.; The World Health Organisation has recently pointed out an alarming increase in the incidence of antibiotic resistant strains of Salmonella, which are due to the use of antibiotics in intensive breeding . In France, until recent years, no or few cases of a

Euro Surveill, 1997 Nov, 2(11), 86 - 88
Minimising the risk of salmonellosis from eggs; Comite Editorial / Editorial Committee; Outbreaks of Salmonella enteritidis associated with raw eggs continue to be common, despite the risk of using raw eggs being well known . In many cases S . enteritidis isaself-limitingillnessbut- particularlyinvery young and very old people - it can be seve

Euro Surveill, 1997 Nov, 2(11), 84 - 86
An outbreak of Salmonella enteritidis food poisoning in a psychiatric hospital in Dublin, Ireland; Grein T et al.; On 29 August 1996 Ireland's Eastern Health Board (EHB) was informed of an outbreak of gastrointestinal illness in a psychiatric hospital in Dublin . Fifty people among 240 members of staff and 183 patients had reportedly fallen ill since 27 August and new

Euro Surveill . 1995 Sep;:7-8.
Salm-Net: a network for human salmonella surveillance in Europe; Fisher IS; Salm-Net aims to prevent human salmonellosis within the EU by strengthening international laboratory based human salmonella surveillance and creating an on-line European database of compatible data available to all participants . Salm-Netis funded by DG XI

Euro Surveill, 1996 Feb, 1(2), 9 - 10
Outbreak of Salmonella dublin infection in France, November - December 1995; Vaillant V et al.; On 20 December 1995, the National Network of Public Health (Reseau National de Sante Publique - RNSP) was notified by the Salmonella and Shigella National Reference Centre (Centre National de Reference - CNR) that a greater than expected number of human i

Dev Comp Immunol, 2003 May, 27(5), 423 - 9
Oxidative burst mediated by toll like receptors (TLR) and CD14 on avian heterophils stimulated with bacterial toll agonists; Farnell MB et al.; Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS) and lipoteichoic acid (LTA), which are found in the cell walls of gram-negative and gram-positive bacteria, respectively . This study was conducted to determine if TLRs are present on chicken heterophils and if these receptors mediate oxidative burst . Heterophils isolated from neonatal chicks were exposed to gram-negative Salmonella enteritidis (SE), gram-positive Staphylococcus aureus (SA), SE-LPS, and SA-LTA and the oxidative burst quantitated by luminol-dependent chemiluminescence . SE, SA, SE-LPS, and SA-LTA stimulated a significant increase in oxidative burst from heterophils . Furthermore, we measured the inhibitory effects of polyclonal antibodies on rat CD14, human TLR2 and TLR4 on the oxidative burst of heterophils when stimulated with LPS and LTA . The data suggest that TLR2 and TLR4 mediate LPS-stimulated oxidative burst while CD14 and TLR2 mediate LTA-stimulated oxidative burst in heterophils . This is the first report of PAMPs from gram-positive and gram-negative bacteria interacting with TLRs of avian heterophils.

Microb Pathog, 2003 Mar, 34(3), 149 - 54
Systemic and enteric colonization of pigs by a hilA signature-tagged mutant of Salmonella choleraesuis; Lichtensteiger CA et al.; Although host adapted to pigs, Salmonella enterica serovar Choleraesuis (S . choleraesuis) can induce a virulent foodborne salmonellosis in humans . To directly investigate virulence factors of S . choleraesuis, we extended the functional genomics approach of signature-tagged mutagenesis to S . choleraesuis and pigs . When a test pool of 45 randomly signature-tagged null mutants was inoculated orally and intraperitoneally in pigs, one of the mutants that failed to colonize by either route was tagged in hilA . In the broad host range serovar S . typhimurium, hilA regulates invasion genes in the first pathogenicity island and is required for enteric but not systemic infections in mice experimentally infected with S . typhimurium . The pool of tagged S . choleraesuis null mutants was a complex mix inoculated in pigs . When pigs were challenged with an equal mixture of the hilA mutant and wild type bacteria, the hilA mutant was at a competitive disadvantaged (attenuated) in pigs inoculated orally but not in intraperitoneally inoculated pigs . Our data support that hilA in S . choleraesuis infections of pigs has a role in enteric but not systemic infections similar to that of S . typhimurium in the murine model of human typhoid fever . The role of hilA may be conserved across Salmonella serovars and host species.

Microb Pathog, 2003 Mar, 34(3), 115 - 9
Construction and evaluation of a eukaryotic expression plasmid for stable delivery using attenuated Salmonella; Garmory HS et al.; An approach to enhancing the stability of eukaryotic expression plasmids for delivery using attenuated Salmonella has been evaluated . The expression apparatus and beta-galactosidase gene from the expression plasmid, pCMVbeta, was cloned into the low copy number plasmid pLG339 . The resulting construct, pLGbetaGAL, was shown to have a lower copy number than pCMVbeta in Salmonella enterica var Typhimurium aroA strain SL7207 . Furthermore, beta-galactosidase-specific antibody was induced in mice following intramuscular inoculation with pLGbetaGAL as naked DNA . Following oral administration of mice with SL7207/pCMVbeta, recombinants could not be detected in tissues 3 days after inoculation . In comparison, SL7207/pLGbetaGAL recombinant bacteria could be detected in the Peyer's patches and spleens indicating that the Salmonella strain was stable . However, both SL7207/pCMVbeta and SL7207/pLGbetaGAL failed to induce beta-galactosidase-specific IgG in vivo . The mechanism by which attenuated Salmonella are able to release heterologous DNA for antigen processing and presentation is not yet understood . These results suggest that the mechanism needs to be further elucidated in order to rationally improve the system.

J Appl Microbiol, 2003, 94(4), 625 - 32
Adaptive responses of Salmonella enterica serovar Typhimurium DT104 and other S . Typhimurium strains and Escherichia coli O157 to low pH environments; de Jonge R et al.; AIMS: Cattle are a known main reservoir for acid-resistant Escherichia coli O157 and Salmonella enterica serovar Typhimurium DT104 . We studied the response of S . Typhimurium DT104 to extreme low pH environments and compared their response to that of acid-resistant E . coli O157 and other S . Typhimurium phage types . METHODS AND RESULTS: Bacteria were grown in nutrient-rich medium and subsequently acid challenged at pH 2.5 . We found that stationary phase cultures of various S . Typhimurium strains were able to survive a challenge for 2 h at pH 2.5 . As in E . coli, the ability of S . Typhimurium to survive at pH 2.5 was shown to be dependent on the presence of amino acids, specifically arginine . The amount of proton pumping H+/ATPase, both in E . coli O157 and S . Typhimurium strains, was lower when grown at pH values <6 than after growth at pH 7.5 . Cyclo fatty acid content of membranes of bacteria grown at pH values <6 was higher than that of membranes of bacteria grown at pH 7.5 . CONCLUSIONS: Various S . Typhimurium strains, both DT104 and non-DT104, are able to survive for a prolonged period of time at pH 2.5 . Their response to such low pH environment is seemingly similar to that of E . coli O157 . SIGNIFICANCE AND IMPACT OF THE STUDY: Food-borne pathogens like S . Typhimurium DT104 and E . coli O157 form a serious threat to public health since such strains are able to survive under extreme low pH conditions as present in the human stomach . The emergence these acid-resistant strains suggests the presence of a selection barrier . The intestinal tract of ruminants fed a carbohydrate-rich diet might be such a barrier.

J Trop Pediatr, 2003 Feb, 49(1), 37 - 41
Antimicrobial susceptibility and distribution of non-typhoidal Salmonella serovars isolated in Malaysian children; Lee WS et al.; There is widespread resistance of Salmonella species to commonly prescribed antimicrobials the world over . We aimed to determine the antimicrobial susceptibility and serovar distribution of non-typhoidal Salmonella (NTS) isolated from blood cultures of Malaysian children . Positive isolates of NTS from blood cultures obtained from children admitted to the pediatric wards of University of Malaya Medical Center (UMMC), a large urban hospital from Kuala Lumpur (1991-2001), and Hospital Kota Bharu (HKB), from the predominantly rural state of Kelantan (1991-1999), Malaysia, were reviewed retrospectively . Serovar distribution and antimicrobial susceptibility were ascertained . A total of 64 and 55 isolates of NTS were obtained from blood cultures of children admitted to UMMC and HKB, respectively . The commonest serovar isolated was Salmonella enteritidis in both centers . The NTS isolated were highly sensitive to the antimicrobials tested: ampicillin 98 per cent, chloramphenicol 98 per cent, gentamicin 97 per cent, trimethoprim-sulfamethoxazole (TMP-SMX) 98 per cent, and ceftriaxone 100 per cent in UMMC; ampicillin 100 per cent, chloramphenicol 87 per cent, kanamycin 100 per cent, streptomycin 96 per cent, TMP-SMX 93 per cent, and tetracycline 89 per cent in HKB . There were only one and five multi-resistant isolates in UMMC and HKB, respectively . In conclusion, NTS isolated from blood cultures of Malaysian children from Kuala Lumpur and Kota Bharu were highly sensitive to commonly prescribed antibiotics . We speculate that this is due to the restriction of sales of antimicrobials in Malaysia except by prescription . Continuing vigilance and frequent antmicrobial surveillance is necessary.

Sante, 2002 Oct-Dec, 12(4), 369 - 74
{Microbial quality assessment of some street food widely consumed in Ouagadougou, Burkina Faso}; Barro N et al.; The major part of the population of Ouagadougou, Burkina Faso, have their breakfast, dinner and lunch in street food shops . The characteristics of street food vendors are indicated . It appeared clearly that women play a major part (75%) in street food sale . Vendors have only a slight knowledge of food processing and of hygienic practices . There is a high proportion (about 50%) of people among them . This dietary habit has some negative aspects on the consumers' health . Ours studies clearly showed that hygienic practices during sales operations are not respected by all categories of vendors of food products . Also, it was observed that street food vendors sometimes sit close to the waste water drainage system and solid wastes . Sometimes, the food is not covered and it is manipulated by consumers in areas infested by flies and others insects . The water used to wash the materials is of poor quality . The second aspects of our studies showed that, in most cases, when the safety and hygienic practices were not respected, the food became a true microorganism culture medium under tropical climatic conditions . A table reports microbial analysis and contamination rates of some important street foods consumed in Ouagadougou . In general these results showed the failure of microbial quality of some food which is not preheated (milk product, fruit juice, vegetable, fruit) and in the case of food which is not reheated after a long time of exposition (dry meat and meat on sticks) . The presence of Salmonella and Shigella species in some food represents a serious danger for consumers . These aspects were observed with most street food vendors . It probably makes street food the source of most diseases caused by bacteria and other microorganisms.

Microbiology, 2003 Feb, 149(Pt 2), 525 - 35
CsgD, a regulator of curli and cellulose synthesis, also regulates serine hydroxymethyltransferase synthesis in Escherichia coli K-12; Chirwa NT et al.; The homologous CsgD and AgfD proteins are members of the FixJ/UhpA/LuxR family and are proposed to regulate curli (thin aggregative fibres) and cellulose production by Escherichia coli and Salmonella enterica serovar Typhimurium, respectively . A plasmid containing part of the csgD gene was isolated during a screen for multicopy suppressors of glycine auxotrophy caused by deleting the folA gene in E . coli . The sequence of the plasmid suggests it encodes a chimaeric protein . Plasmids containing the intact csgD or agfD gene also caused suppression . Cells transformed with the recombinant plasmids contained higher serine hydroxymethyltransferase (SHMT) activity than controls . The increase could also be monitored by assaying beta-galactosidase activity from a reporter strain with part of the SHMT gene, glyA, fused to lacZ . The increase in SHMT activity was sufficient to correct the glycine auxotrophy of strains lacking folA . The recombinant plasmids also enabled K-12 strains that are not curli-proficient to make curli . Curlin, the major component of curli, contains more glycine than normal E . coli proteins . It is proposed that CsgD upregulates glyA to facilitate synthesis of curli . It is suggested that recombinant plasmids produce enough CsgD or chimaeric protein to titrate out a ligand that switches CsgD into its inactive form . As a result, sufficient active CsgD is present to activate genes in its regulon . It is concluded that CsgD increases expression of the glyA gene either directly or indirectly.

J Clin Microbiol, 2003 Mar, 41(3), 1130 - 4
Comparison of four chromogenic media and Hektoen agar for detection and presumptive identification of Salmonella strains in human stools; Perez JM et al.; Several chromogenic media have been developed to enhance the specificity of Salmonella detection . We compared the performance of four commercial chromogenic media-namely, ABC medium (Lab M . Ltd., Bury, United Kingdom), COMPASS Salmonella agar (Biokar Diagnostics, Beauvais, France), CHROMagar Salmonella agar (CHROMagar Company, Paris, France), and SM ID agar (bioMerieux, Marcy l'Etoile, France)-with conventional Hektoen medium . Nine hundred sixteen stool samples from inpatients at three hospitals were cultured, in parallel, on the five media, both by direct inoculation and after selective enrichment in selenite broth . Sixty-four Salmonella strains with 12 serotypes were isolated on at least one medium . After 48 h of incubation, sensitivity before and after enrichment was 62.5 and 89.1% with ABC medium, 77.1 and 93.8% with COMPASS agar, 66.7 and 89.1% with CHROMagar, 68.8 and 85.9% with SM ID agar, and 85.4 and 98.4% with Hektoen agar, respectively . Broth enrichment and prolonged incubation (48 versus 24 h) increased the sensitivity of all five media . Only one strain was not isolated on Hektoen agar . The number of false-positive isolates was higher with all five media after enrichment in selenite broth and after incubation for 48 h compared to 24 h . The specificity of the four chromogenic media was better than 91% after incubation for 24 h (77.7% with Hektoen agar) and better than 84% after incubation for 48 h (74.8% with Hektoen agar) . This higher specificity reduces the need for confirmatory tests, thereby cutting technical time and reagent requirements . Both COMPASS agar and CHROMagar Salmonella, which after simple additional tests showed close efficiencies (96 and 97%, respectively), can be recommended as single-plate media of choice for the detection and presumptive identification of salmonellae in stools.

J Clin Microbiol, 2003 Mar, 41(3), 1023 - 32
Epidemiology of tetracycline resistance determinants in Shigella spp . and enteroinvasive Escherichia coli: characterization and dissemination of tet(A)-1; Hartman AB et al.; To make a comprehensive study of tetracycline resistance determinant distribution in the genus Shigella, a collection of 577 clinical isolates of Shigella spp . and enteroinvasive Escherichia coli (EIEC) from a variety of geographical locations was screened to identify tetracycline-resistant strains . The 459 tetracycline-resistant isolates identified were then screened by PCR analysis to determine the distribution in these strains of tetracycline efflux resistance determinants belonging to classes A to E, G, and H that have been identified in gram-negative bacteria . Only classes A to D were represented in these strains . Although Tet B was the predominant determinant in all geographical locations, there were geographical and species differences in the distribution of resistance determinants . An allele of tet(A), designated tet(A)-1, was identified and sequenced, and the 8.6-kb plasmid containing determinant Tet A-1, designated pSSTA-1, was found to have homologies to portions of a Salmonella enterica cryptic plasmid and the broad-host-range resistance plasmid RSF1010 . This allele and pSSTA-1 were used as epidemiological markers to monitor clonal and horizontal transmission of determinant Tet A-1 . An analysis of serotype, distribution of tetracycline resistance determinants, and resistance profiles indicated that both clonal spread and horizontal transfer had contributed to the spread of specific tetracycline resistance determinants in these populations and demonstrated the use of these parameters as an epidemiological tool to follow the transmission of determinants and strains.

Mutagenesis, 2003 Mar, 18(2), 113 - 8
Antimutagenic activity of extracts of natural substances in the Salmonella/microsome assay; Horn RC et al.; Scientific information regarding plants used in folk medicine in the form of teas and their effect on human health or on genetic material has been the subject of many different types of investigation . The antimutagenic activity of two plants Maytenus ilicifolia and Peltastes peltatus, both rich in compounds of the flavonoid and tannin groups and frequently employed in folk medicine, was studied . Antimutagenicity was determined against known mutagenic substances (4-oxide-1-nitroquinoline, sodium azide, 2-nitrofluorene, aflatoxin B(1), 2-aminofluorene and 2-aminoanthracene), using the Salmonella/microsome assay . Infusions of P.peltatus showed high cytotoxicity and a co-mutagenic effect for induction of base pair substitution mutations with 4-oxide-1-nitroquinoline (-S9 mix) . Infusions of M.ilicifolia produced similar effects for frameshift and base pair substitution mutations . With the mutagens 2-nitrofluorene (TA98) and sodium azide (TA100) no significant enhancement effects (co-mutagenic effects) were observed and inhibition of mutagenic activity and cytotoxicity were also diminished . In assays evaluating antimutagenic activity in the presence of metabolic activation utilizing S9 mix, high and significant inhibition of aflatoxin B(1)-, 2-aminofluorene- and 2-aminoanthracene-induced mutagenicity was observed in the presence of the infusions using both TA98 and TA100 and employing doses ranging from 25 to 500 mg/plate . Seventy-five percent of the doses tested exhibited a significant or suggestive decrease in induced mutagenicity with the infusion of M.ilicifolia . With the infusion of P.peltatus significant or suggestive antimutagenic responses were observed with 50% of the doses evaluated . Complexity was clearly noted in the responses observed in the interaction of aqueous extracts of M.ilicifolia and P.peltastes with the genetic material and metabolites generated by the S9 mix played an important role in the protection of DNA.

Appl Environ Microbiol, 2003 Mar, 69(3), 1783 - 90
Kinetics and strain specificity of rhizosphere and endophytic colonization by enteric bacteria on seedlings of Medicago sativa and Medicago truncatula; Dong Y et al.; The presence of human-pathogenic, enteric bacteria on the surface and in the interior of raw produce is a significant health concern . Several aspects of the biology of the interaction between these bacteria and alfalfa (Medicago sativa) seedlings are addressed here . A collection of enteric bacteria associated with alfalfa sprout contaminations, along with Escherichia coli K-12, Salmonella enterica serotype Typhimurium strain ATCC 14028, and an endophyte of maize, Klebsiella pneumoniae 342, were labeled with green fluorescent protein, and their abilities to colonize the rhizosphere and the interior of the plant were compared . These strains differed widely in their endophytic colonization abilities, with K . pneumoniae 342 and E . coli K-12 being the best and worst colonizers, respectively . The abilities of the pathogens were between those of K . pneumoniae 342 and E . coli K-12 . All Salmonella bacteria colonized the interiors of the seedlings in high numbers with an inoculum of 10(2) CFU, although infection characteristics were different for each strain . For most strains, a strong correlation between endophytic colonization and rhizosphere colonization was observed . These results show significant strain specificity for plant entry by these strains . Significant colonization of lateral root cracks was observed, suggesting that this may be the site of entry into the plant for these bacteria . At low inoculum levels, a symbiosis mutant of Medicago truncatula, dmi1, was colonized in higher numbers on the rhizosphere and in the interior by a Salmonella endophyte than was the wild-type host . Endophytic entry of M . truncatula appears to occur by a mechanism independent of the symbiotic infections by Sinorhizobium meliloti or mycorrhizal fungi.

Appl Environ Microbiol, 2003 Mar, 69(3), 1452 - 6
Survival of bacterial indicator species and bacteriophages after thermal treatment of sludge and sewage; Moce-Llivina L et al.; The inactivation of naturally occurring bacterial indicators and bacteriophages by thermal treatment of a dewatered sludge and raw sewage was studied . The sludge was heated at 80 degrees C, and the sewage was heated at 60 degrees C . In both cases phages were significantly more resistant to thermal inactivation than bacterial indicators, with the exception of spores of sulfite-reducing clostridia . Somatic coliphages and phages infecting Bacteroides fragilis were significantly more resistant than F-specific RNA phages . Similar trends were observed in sludge and sewage . The effects of thermal treatment on various phages belonging to the three groups mentioned above and on various enteroviruses added to sewage were also studied . The results revealed that the variability in the resistance of phages agreed with the data obtained with the naturally occurring populations and that the phages that were studied were more resistant to heat treatment than the enteroviruses that were studied . The phages survived significantly better than Salmonella choleraesuis, and the extents of inactivation indicated that naturally occurring bacteriophages can be used to monitor the inactivation of Escherichia coli and Salmonella.

Lancet, 2003 Mar 1, 361(9359), 743 - 9
Genome sequence of Vibrio parahaemolyticus: a pathogenic mechanism distinct from that of V cholerae; Makino K et al.; BACKGROUND: Vibrio parahaemolyticus, a gram-negative marine bacterium, is a worldwide cause of food-borne gastroenteritis . V parahaemolyticus strains of a few specific serotypes, probably derived from a common clonal ancestor, have lately caused a pandemic of gastroenteritis . The organism is phylogenetically close to V cholerae, the causative agent of cholera . METHODS: The whole genome sequence of a clinical V parahaemolyticus strain RIMD2210633 was established by shotgun sequencing . The coding sequences were identified by use of Gambler and Glimmer programs . Comparative analysis with the V cholerae genome was undertaken with MUMmer . FINDINGS: The genome consisted of two circular chromosomes of 3288558 bp and 1877212 bp; it contained 4832 genes . Comparison of the V parahaemolyticus genome with that of V cholerae showed many rearrangements within and between the two chromosomes . Genes for the type III secretion system (TTSS) were identified in the genome of V parahaemolyticus; V cholerae does not have these genes . INTERPRETATION: The TTSS is a central virulence factor of diarrhoea-causing bacteria such as shigella, salmonella, and enteropathogenic Escherichia coli, which cause gastroenteritis by invading or intimately interacting with intestinal epithelial cells . Our results suggest that V parahaemolyticus and V cholerae use distinct mechanisms to establish infection . This finding explains clinical features of V parahaemolyticus infections, which commonly include inflammatory diarrhoea and in some cases systemic manifestations such as septicaemia, distinct from those of V cholerae infections, which are generally associated with non-inflammatory diarrhoea.

FEMS Microbiol Lett, 2003 Feb 28, 219(2), 215 - 8
Histopathological study of rabbit intestinal mucosa infected with a hybrid strain of Shigella dysenteriae 1 carrying LPS biosynthesis genes of Salmonella enterica serovar typhimurium; Hens DK et al.; The rfb gene cluster and the rfc gene of Salmonella enterica were introduced earlier into an invasive Shigella dysenteriae 1 strain by triparental cross . Antiserum was raised in rabbit against lipopolysaccharide isolated from the hybrid strain . Both the hybrid and the invasive S . dysenteriae 1 strain were found to have a titer of 1:2560 while for S . enterica, it was 1:640 . Ligated ileal loops were prepared in rabbit, which were inoculated with 10(8) CFU ml(-1) each of the hybrid strain, and invasive S . dysenteriae 1 strain used as positive control . Escherichia coli K12 was also used as a negative control . After 18 h, the fluid accumulation ratios were 0.2 and 1.6 for hybrid and invasive strains of S . dysenteriae 1, respectively . Rabbit intestinal mucosa infected with hybrid S . dysenteriae 1 strain showed the presence of intact villus tips and unruptured intestinal mucosa whereas total necrosis of intestinal mucosa and villi was observed in the S . dysenteriae 1-infected region.

Poult Sci, 2003 Feb, 82(2), 259 - 66
Natural resistance-associated macrophage protein 1 gene polymorphisms and response to vaccine against or challenge with Salmonella enteritidis in young chicks; Liu W et al.; Salmonella enteritidis (SE) contamination of poultry products is of global food-safety concern . The natural resistance-associated macrophage protein 1 (NRAMP1) affects host innate immunity to intracellular bacteria because of its ability to transport divalent cations in late endosome/lysosomes . Studying the association of the NRAMP1 gene and chicken innate immune response to SE can, therefore, aid understanding and enhancement of chicken genetic resistance to SE . The chicken NRAMP1 gene was investigated as a candidate gene for SE response in a unique resource population . Outbred broiler sires and three diverse, highly inbred dam lines (two major histocompatibility complex-congenic Leghorn and one Fayoumi line) produced F1 progeny that were evaluated as young chicks for either bacterial load in spleen and cecum after pathogenic SE inoculation or antibody level after SE vaccination . Thirty-seven single nucleotide polymorphisms (SNP) were identified in 3.1 kb of genomic DNA of the NRAMP1 gene . A PCR-RFLP assay was developed to identify a SNP in a conserved transport motif . The sire NRAMP1 gene SNP was associated (P < 0.02) with antibody level to SE vaccine for Sire 8170 offspring in the two Leghorn crosses . In Sire 8296 offspring, NRAMP1 was associated (P < 0.02) with spleen bacterial load in the combined dam-line crosses . This study demonstrated the association of a SNP polymorphism in a highly conserved region of NRAMP1 with SE vaccine and pathogen challenge response in young chicks, indicating that either NRAMP1 or a linked gene controls these SE-response traits.

J Bacteriol, 2003 Mar, 185(6), 1935 - 41
Mutational analysis of the residue at position 48 in the Salmonella enterica Serovar Typhimurium PhoQ sensor kinase; Sanowar S et al.; The PhoP/PhoQ two-component regulatory system of Salmonella enterica serovar Typhimurium plays an essential role in controlling virulence by mediating the adaptation to Mg(2+) depletion . The pho-24 allele of phoQ harbors a single amino acid substitution (T48I) in the periplasmic domain of the PhoQ histidine kinase sensor . This mutation has been shown to increase net phosphorylation of the PhoP response regulator . We analyzed the effect on signaling by PhoP/PhoQ of various amino acid substitutions at this position (PhoQ-T48X {X = A, S, V, I, or L}) . Mutations T48V, T48I, and T48L were found to affect signaling by PhoP/PhoQ both in vivo and in vitro . Mutations PhoQ-T48V and PhoQ-T48I increased both the expression of the mgtA::lacZ transcriptional fusion and the net phosphorylation of PhoP, conferring to cells a PhoP constitutively active phenotype . In contrast, mutation PhoQ-T48L barely responded to changes in the concentration of external Mg(2+), in vivo and in vitro, conferring to cells a PhoP constitutively inactive phenotype . By analyzing in vitro the individual catalytic activities of the PhoQ-T48X sensors, we found that the PhoP constitutively active phenotype observed for the PhoQ-T48V and PhoQ-T48I proteins is solely due to decreased phosphatase activity . In contrast, the PhoP constitutively inactive phenotype observed for the PhoQ-T48L mutant resulted from both decreased autokinase activity and increased phosphatase activity . Our data are consistent with a model in which the residue at position 48 of PhoQ contributes to a conformational switch between kinase- and phosphatase-dominant states.

Genetics, 2003 Feb, 163(2), 545 - 55
Short-chain fatty acid activation by acyl-coenzyme A synthetases requires SIR2 protein function in Salmonella enterica and Saccharomyces cerevisiae; Starai VJ et al.; SIR2 proteins have NAD(+)-dependent histone deacetylase activity, but no metabolic role has been assigned to any of these proteins . In Salmonella enterica, SIR2 function was required for activity of the acetyl-CoA synthetase (Acs) enzyme . A greater than two orders of magnitude increase in the specific activity of Acs enzyme synthesized by a sirtuin-deficient strain was measured after treatment with homogeneous S . enterica SIR2 protein . Human SIR2A and yeast SIR2 proteins restored growth of SIR2-deficient S . enterica on acetate and propionate, suggesting that eukaryotic cells may also use SIR2 proteins to control the synthesis of acetyl-CoA by the level of acetylation of acetyl-CoA synthetases . Consistent with this idea, growth of a quintuple sir2 hst1 hst2 hst3 hst4 mutant strain of the yeast Saccharomyces cerevisiae on acetate or propionate was severely impaired . The data suggest that the Hst3 and Hst4 proteins are the most important for allowing growth on these short-chain fatty acids.

Mol Immunol, 2003 Mar, 39(13), 763 - 70
Induction of innate immunity by IL-2-expressing Salmonella confers protection against lethal infection; al-Ramadi BK et al.; Previously, we demonstrated that an attenuated Salmonella strain expressing IL-2 (designated GIDIL2) is cleared from the circulation at a much faster rate than the non-cytokine-expressing parental strain (designated BRD509) . These findings suggested that IL-2 expression led to the rapid induction of innate immune responses that, in turn, accounted for the accelerated rate of bacterial clearance . In the present study, the mechanism by which this early antibacterial response is mediated was investigated . We demonstrate that as early as 2 h after infection with GIDIL2, but not BRD509, peritoneal excudate cells exhibited enhanced NK cytotoxic activity and upregulated NOS2 mRNA and NO production . This early response coincided with an enhancement of GIDIL2 clearance from the peritoneal cavity, first evidenced 22 h post-infection . Moreover, it conferred a high level of protection against virulent Salmonella challenge given within 16-20 h of GIDIL2 administration . These findings highlight the importance of innate immunity in the control of early bacterial proliferation and demonstrate the rapidity by which these responses are induced following bacterial entry .

Epidemiol Infect, 2003 Feb, 130(1), 13 - 21
Outbreaks of typhoid fever in the United States, 1960-99; Olsen SJ et al.; Although the incidence of typhoid fever in the United States has been low since the 1940s, Salmonella Typhi continues to cause outbreaks . We reviewed reported outbreaks of typhoid fever from 1960 to 1999 . There were 60 outbreaks; in 54, exposure occurred within the United States . These 54 outbreaks accounted for 957 total cases (median 10) and 4 deaths . In 36 (67%) outbreaks the route of transmission was identified, and in 16 (62%) of the 26 foodborne outbreaks an asymptomatic carrier was identified by culture or serology . The median incubation period was 2 weeks . Isolates from 10 (40%) of 25 outbreaks were phage type E1 . The average frequency of outbreaks decreased from 1.85/year during 1960-79 to 0.85/year during 1980-99 (P=0.0001) . S . Typhi outbreaks in the United States are generally small in size but can cause significant morbidity, and are often foodborne, warranting thorough investigation.

Biotechniques, 2003 Feb, 34(2), 304 - 10, 313
Subtracted restriction fingerprinting--a tool for bacterial genome typing; Terletski V et al.; Reproducible, discriminative, high-throughput methods are required for the identification of bacterial strains and isolates in a clinical environment . A new molecular typing method for bacteria was developed and tested on Salmonella and E . coli species . The technique is called subtracted restriction fingerprinting and is based on double restriction enzyme digestion of genomic DNA followed by end labeling . The "detection" enzyme produces TTAA overhangs that are filled in with digoxigenated nucleotides for subsequent detection, while the "subtraction" enzyme produces GCGC overhangs that are filled in with biotinylated nucleotides that permit the removal of this subset of fragments with either streptavidin-coated magnetic particles or AffiniTip streptavidin columns . The two restriction enzymes are selected to produce a fragment size profile suitable for a specific analytical system . In this demonstration of the principle of subtracted restriction fingerprinting, analysis of Salmonella enterica subsp . enterica serovar Dublin and E . coli on a 30-cm 1.2% agarose gel revealed up to 50 sharp evenly spaced bands, which were sufficient for the discrimination between various isolates and substrains . The restriction enzyme combinations suitable for the analysis of Salmonella and E . coli are presented . The method requires fewer enzymatic steps than amplified fragment length polymorphism, does not need the specialized DNA preparation essential for pulsed field gel electrophoresis, and has a higher reproducibility than PCR-based methods.

Am J Kidney Dis, 2003 Mar, 41(3), 709 - 13
Hemolytic uremic syndrome in association with typhoid fever; Albaqali A et al.; BACKGROUND: Hemolytic uremic syndrome (HUS) has been associated with typhoid fever caused by Salmonella typhi . The pathogenesis of HUS in the context of S typhi infection is not known . The authors report on a patient with typhoid fever in whom HUS and myocarditis developed during the course of his illness and in whom there was no evidence of a Shiga-toxin (Stx)-producing organism . METHODS: Antibodies directed against the Escherichia coli O157:H7 and S typhi lipopolysaccharide (LPS) were sought in the serum sample taken during the acute phase using line-blot immunoassays . Polymerase chain reaction was performed to detect the presence of stx1 and stx2 genes in the patient's S typhi isolate . RESULTS: There was no evidence for immunoglobulin (Ig) M and IgA against the LPS of E coli O157:H7, whereas anti-S typhi LPS IgM and IgA were strongly positive . In the polymerase chain reaction, DNA from the Stx-producing E coli controls yielded stx1 and stx2 fragments of the expected sizes on agarose gel electrophoresis, whereas no stx1 and stx2 fragments were obtained from the S typhi isolate . The S typhi did, however, yield a band when amplified with primers specific for viaB, an S typhi gene . CONCLUSION: S typhi may be responsible for some cases of HUS, and the inciting toxin may not be Stx .

J Microbiol Methods, 2003 Apr, 53(1), 77 - 86
A simple micro-growth assay for enumerating bacteria; Brewster JD; A simple method for nonspecific determination of bacteria concentrations in a variety of liquid samples was developed . The assay was based on the time required for a sample grown in liquid media to reach a threshold turbidity . Samples were combined with media in a covered 96-well microwell plate and the turbidity was monitored in real time as the bacteria grew in a temperature-controlled plate reader . A significant problem with growth in microwells was condensation on the cover, which prevented accurate turbidity measurement . This problem was overcome by coating the cover with a small amount of surface-active agent . Salmonella and E . coli concentrations could be determined with a relative error of approximately 20% at levels from 10 to 10(6) cells/ml (eight replicates) . An assay of 10 samples with standards required 10 min to set up and 20 min for data processing using a computer spreadsheet program . Growth time at 37 degrees C ranged from 4 h for samples at 10(7) cells/ml to 16 h for samples at 10 cells/ml.

Environ Mol Mutagen, 2003, 41(2), 111 - 20
Mouse bone marrow micronucleus test results do not predict the germ cell mutagenicity of N-hydroxymethylacrylamide in the mouse dominant lethal assay; Witt KL et al.; N-Hydroxymethylacrylamide (NHMA), a mouse carcinogen inactive in the Salmonella assay and mouse micronucleus (MN) assay, was tested for reproductive effects in a mouse continuous breeding study . In that study, increased embryonic deaths were observed after 13 weeks exposure of parental animals to NHMA via drinking water (highest dose, 360 ppm); the results indicated the possible induction of chromosome damage in germ cells of treated males . An additional mouse MN test was conducted using a 31-day treatment period to better match the dosing regimen used in the breeding study; the results were negative . Additional studies were conducted to explore the germ cell activity of NHMA . A male mouse dominant lethal study was conducted using a single intraperitoneal injection of 150 mg/kg NHMA; the results were negative . A follow-up study was conducted using fractionated dosing, 50 mg/kg/day for 5 days; again, no increase in dominant lethal mutations was observed . NHMA (180-720 ppm) was then administered to male mice in drinking water for 13 weeks, during which three sets of matings occurred . Two weeks after mating, females were killed and the uterine contents were analyzed . Large, dose-related increases in dominant lethal mutations were observed with increasing length of exposure . The magnitude of the increases stabilized after 8 weeks of treatment . However, the frequency of micronucleated peripheral blood erythrocytes was not elevated in mice treated for 13 weeks with NHMA in drinking water . Thus, NHMA appears to be unique in inducing genetic damage in germ cells but not somatic cells of male mice.

Antimicrob Agents Chemother, 2003 Mar, 47(3), 1165 - 8
Imipenem resistance in Salmonella enterica serovar Wien related to porin loss and CMY-4 beta-lactamase production; Armand-Lefevre L et al.; Two multidrug-resistant Salmonella enterica serovar Wien strains (SW468 and SW1107) were isolated in 2001 in Tunis . Both strains produced the beta-lactamases TEM-1, SHV-2a, and CMY-4, whereas strain SW1107 also produced the beta-lactamase CTX-M-3 . The imipenem-resistant strain (SW468) was totally devoid of the OmpF-immunorelated porin . Imipenem resistance was shown as being related to porin loss and CMY-4 beta-lactamase production.

Biochem Biophys Res Commun, 2003 Mar 7, 302(2), 219 - 25
A new inhibitor of the transcription-termination factor Rho; Carrano L et al.; In this study we describe BI-K0058, a new inhibitor of the transcription-termination factor Rho belonging to a different chemical class from bicyclomycin, the only known antibiotic acting on Rho . BI-K0058 inhibits the poly(C)-dependent ATPase activity of Rho with an IC(50) of 25 microM as well as in vitro transcription-termination of two natural substrates, the Salmonella enterica hisG cistron and the f1 phage intergenic region . BI-K0058 does not affect photolabeling of Rho by ATP . The results of gel mobility shift experiments with a natural RNA substrate demonstrate that BI-K0058 inhibits the formation of the ATP-independent high affinity Rho-RNA complex.

Mol Microbiol, 2003 Mar, 47(5), 1341 - 51
SseA acts as the chaperone for the SseB component of the Salmonella Pathogenicity Island 2 translocon; Zurawski DV et al.; The Salmonella Pathogenicity Island 2 (SPI2) encodes a type III secretion system (TTSS) shown to be critical for adaptation to the intracellular environment within both phagocytic and epithelial cell types . Within SPI2, the Effector region encodes several exported proteins that comprise the SPI2 translocon (SseB, C, D) . SseA is the first protein encoded within the Effector region but remains an unclassified factor that is essential for SPI2 function . In the present study, we determined that SseA shares several features with TTSS chaperones: it is small (12.5 kDa), located directly upstream of a TTSS export target (SseB), and contains an amphipathic, C-terminal alpha-helix . Construction and analysis of a DeltasseA mutant demonstrated that the total amount of SseB is significantly reduced and SPI2 export of SseB to the bacterial surface is prevented . SseB accumulation and export were restored when SseA was provided in trans . Loss of SseA does not cause a generalized defect in SPI2 secretory function as export of SseC, encoded downstream of SseB, still occurs in the DeltasseA strain . Quantitative PCR indicates that the loss of SseB in DeltasseA does not occur at the transcriptional level . Co-purification studies demonstrate that SseA directly binds to SseB . Collectively, these results demonstrate that SseA functions as a TTSS chaperone for the SPI2 translocon component, SseB.

Comp Immunol Microbiol Infect Dis, 2003 Jan, 26(1), 37 - 45
Hsp60 specific antibodies in egg yolks from laying hens naturally infected with Salmonella enterica subspecies enterica serovar Enteritidis; Dera-Tomaszewska B et al.; Heat shock protein (Hsp) 60 of Salmonella appears to be involved in pathogenesis of infectious processes and host immune responses . Eggs of laying hens from two Salmonella Enteritidis naturally infected flocks (I--acute outbreak of infection; II--occasional bacteria excretion) and one control flock (III) were tested for the presence of yolk antibodies (IgY) against Hsp60 by applying enzyme-linked immunosorbent assay (ELISA) . The levels of specific immunoglobulins were related to those against lipopolysaccharide (LPS) and flagellin . the antigens of the established immunological importance in S . Enteritidis infections . Within flock III, the antibody concentrations were consistently low . Elevated levels were detected in eggs from two infected flocks . Levels of specific IgY measured for flock I were higher than those in flock II; the greatest difference was observed for anti-Hsp60 . This report indicates a probable important role of Hsp60 as a target of the hens' immune response, especially during the acute phase of S . Enteritidis infection.

Indian J Exp Biol, 2002 Jul, 40(7), 831 - 4
Synergistic effect of ayurvedic pearl preparation on enhancing effectiveness of antibiotics; Kulkarni M et al.; Studies were carried out with ayurvedic preparations derived from pearl, which include preparations bhasma and pishti . The synergistic effect to reduce the dose of antibiotic was tested against E . coli the test bacterium with ampicillin antibiotic by bore well and disks diffusion methods . It was observed that pearl preparations do not show any antibacterial activity but when used at 200 microg/ml concentration with antibiotics, then even at sub-lethal dose, the antibiotic has effectively shown the results with reduced contact time . The protocol was also tested with the other bacteria like, Pseudomonas aeruginosa . Vibrio cholarae, Salmonella typhi, and Staphylococcus aureus and has shown similar results . The pearl bhasma synergistic effect was also tested with other antibiotics such as erythromycin, kanamycin, and ampicillin.

J Food Prot, 2003 Feb, 66(2), 324 - 7
Phage typing of Salmonella enteritidis from different sources in Brazil; Nunes IA et al.; The occurrence of Salmonella Enteritidis (SE) phage types (PTs) in samples collected from healthy and diseased chickens, in outbreaks of human gastroenteritis related to the consumption of egg products, in samples of poultry meat, in pipped embryos of broiler chickens, in meat meal, in poultry-rearing environments, and in many foods (cheese, mayonnaise, cake, and bacon) is described for strains isolated from 1995 to 1997 in Brazil . SE strains were isolated, and the most common PT was found to be PT 4, followed by PTs 7, 21, 35, 6, 4a, 8, 30, 6a, 5a, 1, and 1b . Fourteen strains were classified as react-but-do-not-conform strains, and one strain was not typeable . The results of this study demonstrate that PT 4 has a wider distribution among the sources studied than do any other SE phage types and is the most important phage type in human salmonellosis.

J Food Prot, 2003 Feb, 66(2), 242 - 8
Lethality of Salmonella and Listeria innocua in fully cooked chicken breast meat products during postcook in-package pasteurization; Murphy RY et al.; The process lethality model was used to predict the thermal kill of Salmonella and Listeria innocua in fully cooked and vacuum-packaged chicken breast meat during hot-water postprocess pasteurization . Time-temperature profiles of the meat samples during treatment and D-values (decimal reduction times) and z-values (change in temperature required to change the D-value) for Salmonella and L . innocua in the same meat product were used in the prediction of lethality . The results of the model prediction were compared with those of the inoculation study for the same meat product at a 95% confidence level of up to 10(7) CFU/g for Salmonella and L . innocua . The thermal lethality predictions obtained with the process lethality model for Salmonella and L . innocua were within the 95% confidence level for the experimental data from the inoculation study, suggesting that the process lethality model was a useful tool for the determination of the kill of Salmonella or L . innocua at up to 10(7) CFU/g in fully cooked chicken breast meat products during postprocess pasteurization with hot water.

J Food Prot, 2003 Feb, 66(2), 233 - 6
Survival of Salmonella in waste egg wash water; Meckes MC et al.; Waste wash waters from chicken egg-processing facilities can harbor high densities of bacteria, including salmonellae . For this study, we enumerated total coliforms, Escherichia coli, and Salmonella spp . in the egg wash waters of a large egg producer . We then determined how long these organisms would survive at temperatures of 5, 15, and 25 degrees C . We found that the fraction of salmonellae surviving over time at a given temperature was comparable to the fraction of indicator organisms that survived . We also found that the survival of these organisms varied with temperature, with 16, 8, and < 2 days being required for a 90% reduction of Salmonella in waste wash water held at 5, 15, and 25 degrees C, respectively . Finally, we noted that the response of laboratory-derived cultures to environmental stresses mimics the response of the indigenous microbial population, but individual cells within that population may survive for longer periods than laboratory-cultured strains.

J Food Prot, 2003 Feb, 66(2), 215 - 9
Filament formation by Salmonella spp . inoculated into liquid food matrices at refrigeration temperatures, and growth patterns when warmed; Mattick KL et al.; In this study, the formation of multicellular filamentous Salmonella cells in response to low temperatures was investigated by using isolates of Salmonella enterica serovar Enteritidis PT4 and S . enterica serovar Typhimurium DT104 as the inocula . The formation of filamentous cells in two liquid food matrices at the recommended maximum temperature for refrigeration (8 degrees C) was monitored and compared with that in tryptone soya broth . Giemsa staining was performed to locate nuclear material within the filaments . Single filaments were warmed on agar at 37 degrees C, and the subsequent rate of septation was quantified . For all strains tested, > 70% of the Salmonella cells inoculated had become filamentous after 4 days in media at 8 degrees C, indicating that filamentation could occur during the shelf life of most refrigerated foods . Strains with impaired RpoS expression were able to form filaments at 8 degrees C, although these filaments tended to be shorter and less numerous . All strains also formed filamentous cells at 8 degrees C in retail milk or chicken meat extract . Filaments often exceeded 100 microm in length and appeared straight-sided under the microscope in media and in foods, and Giemsa staining demonstrated that regularly spaced nucleoids were present . This phenotype indicates that an early block in cell septation is probably responsible for filamentation . When filaments were warmed on agar at 37 degrees C, there was a rapid completion of septation, and for one filament, a >200-fold increase in cell number was observed within 4 h . There are clear public health implications associated with the filamentation of Salmonella in contaminated foods at refrigeration temperatures, especially when the possibility of rapid septation of filamentous cells upon warming is considered.

J Food Prot, 2003 Feb, 66(2), 188 - 93
Reduction of poliovirus 1, bacteriophages, Salmonella montevideo, and Escherichia coli O157:H7 on strawberries by physical and disinfectant washes; Lukasik J et al.; The efficacy levels of different physical and chemical washing treatments in the reduction of viral and bacterial pathogens from inoculated strawberries were evaluated . Escherichia coli O157:H7, Salmonella Montevideo, poliovirus 1, and the bacteriophages PRD1, phiX174, and MS2 were used as model and surrogate organisms . Chemicals readily available to producers and/or consumers were evaluated as antimicrobial additives for the production of washes . The gentle agitation of contaminated strawberries in water for 2 min led to reductions in microbial populations ranging from 41 to 79% and from 62 to 90% at water temperatures of 22 and 43 degrees C, respectively . Significant reductions (> 98%) in numbers of bacteria and viruses were obtained with sodium hypochlorite (50 to 300 ppm of free chlorine), Oxine or Carnebon (200 ppm of product generating "stabilized chlorine dioxide"), Tsunami (100 ppm of peroxyacetic acid), and Alcide (100 or 200 ppm of acidified sodium chlorite) washes . Overall, 200 ppm of acidified sodium chlorite produced the greatest reductions of microorganisms . Hydrogen peroxide (0.5%) was slightly less effective than free chlorine in a strawberry wash and caused slight fruit discoloration . Cetylpyridinium chloride (0.1%) was effective in the reduction of bacterial species, while trisodium phosphate (1%) was effective against viruses . The consumer-oriented produce wash Fit was very effective (> 99%) in reducing the numbers of bacteria but not in reducing the numbers of viruses . Another wash, Healthy Harvest, was significantly less effective than Fit in reducing bacterial pathogens but more effective for viruses . The performance of automatic dishwashing detergent was similar to that of Healthy Harvest and significantly better than that of liquid dishwashing detergent . Solutions containing table salt (2% NaCl) or vinegar (10%) reduced the numbers of bacteria by about 90%, whereas only the vinegar wash reduced the numbers of viruses significantly (ca . 95%).

J Food Prot, 2003 Feb, 66(2), 182 - 7
Survey of retail alfalfa sprouts and mushrooms for the presence of Escherichia coil O157:H7, Salmonella, and Listeria with BAX, and evaluation of this polymerase chain reaction-based system with experimentally contaminated samples; Strapp CM et al.; BAX, a polymerase chain reaction (PCR)-based pathogen detection system, was used to survey retail sprouts and mushrooms for contamination with Escherichia coli O157:H7, Salmonella, Listeria spp., and Listeria monocytogenes . No Salmonella or E . coli O157:H7 was detected in the 202 mushroom and 206 alfalfa sprout samples screened . L . monocytogenes was detected in one sprout sample, and seven additional sprout samples tested positive for the genus Listeria . BAX also detected Listeria species in 17 of the mushroom samples . Only 6 of 850 PCR assays (0.7%) failed to amplify control DNA, and therefore reagent failures and the inhibition of PCR by plant compounds were rare . The sensitivity of the detection system was evaluated by assaying samples inoculated with 10 CFU of each of the pathogens . One hundred seventy-two alfalfa sprout samples were inoculated with E . coli O157:H7, and two sets of 130 samples were experimentally contaminated with Salmonella Enteritidis and L . monocytogenes . The frequency of detection depended on the protocols used for inoculation and culturing . Inoculation of samples with approximately 10 CFU from frozen stocks yielded detection rates of 87.5 and 94.5% for L . monocylogenes and Salmonella Enteritidis, respectively, in mushrooms . The corresponding rates for alfalfa sprouts were 94.5 and 76.3% . The E . coli O157:H7 detection rate was 100% for mushrooms but only 48.6% for sprouts when standard BAX culture protocols were used . The substitution of an overnight incubation in modified E . coli medium for the 3-h brain heart infusion incubation increased the rate of E . coli O157:H7 detection to 75% for experimentally contaminated sprouts . The detection rate was 100% when E . coli O157:H7 cells from a fresh overnight culture were used for the inoculation . Test sensitivity is therefore influenced by the type of produce involved and is probably related to the growth of pathogens in the resuscitation and enrichment media.

J Food Prot, 2003 Feb, 66(2), 175 - 81
Inactivation of Escherichia coli O157:H7 and Salmonella by gamma irradiation of alfalfa seed intended for production of food sprouts; Thayer DW et al.; Inonizing irradiation was determined to be a suitable method for the inactivation of Salmonella and Escherichia coli O157:H7 on alfalfa seed to be used in the production of food sprouts . The radiation D (dose resulting in a 90% reduction of viable CFU) values for the inactivation of Salmonella and E . coli O157:H7 on alfalfa seeds were higher than the D-values for their inactivation on meat or poultry . The average D-value for the inactivation of Salmonella on alfalfa seeds was 0.97 +/- 0.03 kGy; the D-values for cocktails of meat isolates and for vegetable-associated isolates were not significantly different . The D-values for nonoutbreak and outbreak isolates of E . coli O157:H7 on alfalfa seeds were 0.55 +/- 0.01 and 0.60 +/- 0.01 kGy, respectively . It was determined that the relatively high D-values were not due to the low moisture content or the low water activity of the seed . The D-values for Salmonella on alfalfa seeds from two different sources did not differ significantly, even though there were significant differences in seed size and water activity . The increased moisture content of the seed after artificial inoculation did not significantly alter the D-value for the inactivation of Salmonella . The results of this study demonstrate that 3.3- and 2-log inactivations can be achieved with a 2-kGy dose of ionizing radiation, which will permit satisfactory commercial yields of sprouts from alfalfa seed contaminated with E . coli O157:H7 and Salmonella, respectively.

Microbiol Immunol, 2002, 46(12), 891 - 905
Development of a mucosal complex vaccine against oral Salmonella infection in mice; Harada H et al.; We examined the immunogenicity of a Salmonella enterica complex vaccine (CV), consisting of flagellin and polysome purified from serotype Typhimurium LT2 . CV plus cholera toxin (CT), in three oral doses given at 7-day intervals, conferred complete protection on C57BL/6 mice against lethal oral infection with a wild-type strain . It elicited mucosal IgA > IgG2a > IgG1 and systemic IgG2a > IgG1 > IgA antibodies to flagellin and polysome, and delayed footpad response (DFR) to both antigens . In Peyer's patches (PPs) and lamina propria (LP), IgA was produced under a Th1-dominant environment; CD4+T cells from produced interleukin (IL)-2, interferon (IFN)-gamma, and IL-10 by stimulation with salmonella extract . On the same protocol, flagellin plus CT induced flagellin-specific mucosal and systemic IgA and IgG1 antibodies, CD4+T cells producing IL-10 and IFN-gamma in PPs and LP, and only minimal levels of flagellin-specific DFR . Polysome plus CT induced polysome-specific mucosal and systemic IgG2a in addition to IgG1 and IgA antibodies, CD4+T cells producing IFN-gamma and IL-2 in PPs and LP, and polysome-specific DFR . These two vaccines, however, conferred at most 50-60% survival rates . Our results suggest that polysomes in CV provide effective adjuvant activity for the induction of both mucosal and systemic Th1-biased responses toward flagellin.

Microbiol Immunol, 2002, 46(12), 833 - 40
Molecular epidemiology of Salmonella enterica serovar Enteritidis isolated in Taiwan; Su LH et al.; Incidence of Salmonella enterica serovar Enteritidis infection seems to be on the rise in Taiwan, and therefore, the characteristics of the isolate, including genotypes, were epidemiologically investigated . Of the 71 clinical strains isolated in 1997-1999, 61 (86%) remained susceptible to the eight antibiotics tested, while the remaining ten, eight of which were isolated in 1999, were resistant to one to three of the agents including three multiply resistant strains . The majority, 69 or 97% of the isolates, harbored a 60-kb spvC gene-carrying virulence plasmid and 12 of them harbored one or two additional various-sized plasmids . Strains with more than one plasmid were isolated mostly in 1999 . Pulse-field gel electrophoresis (PFGE) revealed three major genotypes (Types A, B and C), in which type A was the predominant type . Of the 68 Type A, which contained 8 subtypes, 59 (83%) belonged to only two subtypes . Similar results were obtained with a PCR-based typing method, the infrequent-restriction-site (IRS) PCR . All four methods detected types that were rarely seen before and most of these were of recent isolates, indicating that these unusual types were new or strains of foreign origin . Though all four methods discriminated types well, PFGE and IRS-PCR showed higher sensitivity for classification . Between the two, the latter, though less discriminatory than PFGE, seems the method of choice, since it is simpler, less time-consuming and above all easy to perform.

Bull Soc Pathol Exot, 2002 Nov, 95(4), 253 - 6
{Gastrointestinal manifestations of AIDS in adults in Mali}; Maiga MY et al.; Our main objective consists in evaluating the frequency of digestive signs and digestive opportunistic infections in AIDS patients with diarrhea . The prospective study occurred from January 1997 to July 1998 in Bamako hospitals . The patients underwent a clinical examination, blood and stools tests, and sometimes upper digestive endoscopy . Among 434 cases of AIDS, 426 patients (98%) had at least one digestive sign . The main digestive signs were diarrhea (80.1%), abdominal pains (62.2%), vomiting (47.2%) and dysphagea (36.6%) . Isospora belli and Cryptosporidium parvum have been pointed up in respectively 9% and 16.3% of examined specimen . Echerichia coli was found in 8.6% of stool cultures and in 2.9% in the case of Salmonella Arizonae . Twenty cases of Kaposi's sarcoma were diagnosed and mycosis was found in 71.9% of patients . In conclusion, digestive change is a constant phenomenon in AIDS patients . Patients survival could be improved by early management, improvement of diagnosis and provisioning of medicines.

Genes Immun, 2003 Jan, 4(1), 4 - 11
Susceptibility to mycobacterial infections: the importance of host genetics; Bellamy R; There is substantial evidence that host genetic factors are important in determining susceptibility to mycobacteria . Several different techniques have been used to identify the genes involved . Studies of an inbred strain of mice with increased susceptibility to mycobacteria, salmonella and leishmania infections led to the identification of the natural resistance-associated macrophage protein gene (Nramp1) . Case-control studies have confirmed the importance of the human equivalent of this gene, NRAMP1, and have also suggested that the major histocompatibility complex and vitamin-D receptor genes may be involved in determining human susceptibility to mycobacteria . Studies of individuals with the rare condition of increased susceptibility to disseminated bacille Calmette-Guerin and other atypical mycobacterial infections have identified several abnormalities in the genes encoding the interferon gamma receptor (IFNgammaR) ligand binding chain, IFNgammaR signal transduction chain, IFNgamma signal transduction and activation of transcription-1, interleukin 12 receptor beta1 subunit and interleukin 12 p40 subunit . A genome-wide linkage study has been performed to identify genes exerting a major effect on tuberculosis susceptibility in the general population . Linkages were found to markers on chromosomes 15 and X . Studies to identify the genes responsible are in progress.

Infect Immun, 2003 Mar, 71(3), 1295 - 305
HilE interacts with HilD and negatively regulates hilA transcription and expression of the Salmonella enterica serovar Typhimurium invasive phenotype; Baxter MA et al.; The ability of Salmonella enterica serovar Typhimurium to traverse the intestinal mucosa of a host is an important step in its ability to initiate gastrointestinal disease . The majority of the genes required for this invasive characteristic are encoded on Salmonella pathogenicity island 1 (SPI1), and their expression is controlled by the transcriptional activator HilA, a member of the OmpR/ToxR family of proteins . A variety of genes (hilC, hilD, fis, sirA/barA, csrAB, phoB, fadD, envZ/ompR, fliZ, hilE, ams, lon, pag, and hha) have been identified that exert positive or negative effects on hilA expression, although the mechanisms by which these gene products function remain relatively unclear . Recent work indicates that the small DNA-binding protein, Hha, has a significant role in repressing hilA transcription and the invasive phenotype, particularly in response to osmolarity signals . We have characterized the Salmonella-specific gene, hilE, and found that it plays an important regulatory role in hilA transcription and invasion gene expression . Mutation of hilE causes derepression of hilA transcription, and overexpression of hilE superrepresses hilA expression and the invasive phenotype . Bacterial two-hybrid experiments indicate that the HilE protein interacts with HilD, suggesting a possible mechanism for HilE negative regulation of hilA gene expression and the Salmonella invasive phenotype . Finally, we have found that the hilE gene resides on a region of the serovar Typhimurium chromosome that has many characteristics of a pathogenicity island.

Infect Immun, 2003 Mar, 71(3), 1209 - 16
Functional CD40 expression induced following bacterial infection of mouse and human osteoblasts; Schrum LW et al.; Bacterially induced bone infections often result in significant local inflammatory responses which are coupled with loss of bone . However, the mechanisms necessary for the protective host response, or those responsible for pathogen-induced bone loss, are not clear . Recent evidence demonstrates that bacterially infected osteoblasts secrete chemokines and cytokines, suggesting that these cells may have an unappreciated role in supporting localized inflammation . In this study, mouse and human osteoblasts were investigated for their ability to express functional CD40 upon exposure to two important pathogens of bone, Staphylococcus aureus and Salmonella enterica serovar Dublin . Bacterial infection of cultured mouse or human osteoblasts resulted in increased CD40 mRNA and CD40 protein expression induced by either pathogen . Importantly, CD40 expression by osteoblasts was functional, as assessed by ligation of this molecule with recombinant, soluble CD154 . CD40 activity was assessed by induction of interleukin-6 and granulocyte-macrophage colony-stimulating factor in osteoblasts following ligation . Cocultures of activated CD4(+) T lymphocytes and osteoblasts could interact via CD40 and CD154, since an antibody against CD40 could block macrophage inflammatory protein-1alpha secretion . Taken together, these studies conclusively demonstrate that infected osteoblasts can upregulate expression of functional CD40 molecules which mediate cytokine secretion . This surprising result further supports the notion that bone-forming osteoblasts can directly interact with CD154-expressing cells (i.e., T lymphocytes) and can contribute to the host response during bone infection.

Infect Immun, 2003 Mar, 71(3), 1141 - 6
The shufflon of Salmonella enterica serovar Typhi regulates type IVB pilus-mediated bacterial self-association; Morris C et al.; Previously, it was shown that type IVB pili encoded by the Salmonella enterica serovar Typhi pil operon are used to facilitate bacterial entry into human intestinal epithelial cells in vitro and that such entry is inhibited by purified prepilin (pre-PilS) protein (X.-L . Zhang, I . S . M . Tsui, C . M . C . Yip, A . W . Y . Fung, D . K.-H . Wong, X . Dai, Y . Yang, J . Hackett, and C . Morris, Infect . Immun . 68:3067-3073, 2000) . The pil operon concludes with a simple shufflon, and a recombinase gene product (Rci) inverts DNA in the C-terminal region of the pilV gene to allow synthesis of two distinct PilV proteins, PilV1 and PilV2, which are presumptive minor pilus proteins . We show here that the type IVB pili mediate bacterial self-association, but only when the PilV1 and PilV2 proteins are not expressed . This may be achieved in wild-type serovar Typhi by rapid DNA inversion activity of the shufflon . We show that the inversion activity inhibits the expression of genes inserted between the 19-bp inverted repeats used for Rci-mediated recombination and that the activity of Rci increases when DNA is supercoiled . The data suggest that serovar Typhi self-associates under conditions (such as low oxygen tension in the gut) that favor DNA supercoiling . These results explain (i) the function of the serovar Typhi shufflon and (ii) why there are only two possible shufflon states, in contrast to the many possible states of other shufflon systems . The data further indicate that a very early step in serovar Typhi pathogenesis may be type IVB pilus-mediated self-association of bacteria in the anaerobic human small intestine prior to invasion of the human gut epithelium . The suggested type IVB pilus-dependent step in typhoid fever pathogenesis may partially explain the enhanced invasiveness of serovar Typhi for humans.

Infect Immun, 2003 Mar, 71(3), 1116 - 24
Allelic variation in TLR4 is linked to susceptibility to Salmonella enterica serovar Typhimurium infection in chickens; Leveque G et al.; Toll-like receptor 4 (TLR4) is part of a group of evolutionarily conserved pattern recognition receptors involved in the activation of the immune system in response to various pathogens and in the innate defense against infection . We describe here the cloning and characterization of the avian orthologue of mammalian TLR4 . Chicken TLR4 encodes a 843-amino-acid protein that contains a leucine-rich repeat extracellular domain, a short transmembrane domain typical of type I transmembrane proteins, and a Toll-interleukin-1R signaling domain characteristic of all TLR proteins . The chicken TLR4 protein shows 46% identity (64% similarity) to human TLR4 and 41% similarity to other TLR family members . Northern blot analysis reveals that TLR4 is expressed at approximately the same level in all tissues tested, including brain, thymus, kidney, intestine, muscle, liver, lung, bursa of Fabricius, heart, and spleen . The probe detected only one transcript of ca . 4.4 kb in length for all tissues except muscle where the size of TLR4 mRNA was ca . 9.6 kb . We have mapped TLR4 to microchromosome E41W17 in a region harboring the gene for tenascin C and known to be well conserved between the chicken and mammalian genomes . This region of the chicken genome was shown previously to harbor a Salmonella susceptibility locus . By using linkage analysis, TLR4 was shown to be linked to resistance to infection with Salmonella enterica serovar Typhimurium in chickens (likelihood ratio test of 10.2, P = 0.00138), suggesting a role of TLR4 in the host response of chickens to Salmonella infection.

Infect Immun, 2003 Mar, 71(3), 1109 - 15
Enteric salmonella infection inhibits Paneth cell antimicrobial peptide expression; Salzman NH et al.; Paneth cells, highly secretory epithelial cells found at the bases of small intestinal crypts, release a variety of microbicidal molecules, including alpha-defensins and lysozyme . The secretion of antimicrobials by Paneth cells is thought to be important in mucosal host defense against invasion by enteric pathogens . We explored whether enteric pathogens can interfere with this arm of defense . We found that oral inoculation of mice with wild-type Salmonella enterica serovar Typhimurium decreases the expression of alpha-defensins (called cryptdins in mice) and lysozyme . Oral inoculation with Salmonella serovar Typhimurium strains that are heat killed, lack the PhoP regulon, and lack the SPI1 type III secretion system or with Listeria monocytogenes does not have this effect . Salmonella may gain a specific survival advantage in the intestinal lumen by decreasing the expression of microbicidal peptides in Paneth cells through direct interactions between Salmonella and the small intestinal epithelium.

Intensive Care Med, 2003 Feb, 29(2), 301 - 8 Epub 2002 Nov 30.
Terlipressin dose response in healthy and endotoxemic sheep: impact on cardiopulmonary performance and global oxygen transport; Westphal M et al.; OBJECTIVE: To determine whether a goal-directed terlipressin infusion increases mean arterial pressure without causing a pulmonary vasopressive effect and whether this response impacts on key parameters of oxygen transport in healthy and endotoxemic sheep . DESIGN AND SETTING: Prospective controlled trial in a university research laboratory . ANIMALS AND INTERVENTIONS: Six conscious adult ewes instrumented for chronic study received terlipressin as titrated infusion started with 10 microg x kg(-1) x h(-1) and increased by 5 microg x kg(-1) x h(-1) every 15 min, either until mean arterial pressure was increased by 15 mmHg from baseline, or a maximum of 40 microg x kg(-1) x h(-1) was given . Following 24 h of recovery sepsis was induced and maintained in the same ewes by a continuous infusion of endotoxin ( Salmonella typhosa, 10 ng x kg(-1) min(-1)) . After 16 h of endotoxemia the sheep were again treated with terlipressin . MEASUREMENTS AND RESULTS: Systemic oxygen delivery and consumption were calculated before and after the titration period; hemodynamic parameters were measured every 15 min . The increase in mean arterial pressure was greater during endotoxemia than in healthy controls . In both states terlipressin administration decreased cardiac index and diminished oxygen delivery and consumption . While mean pulmonary arterial pressure remained constant, terlipressin increased the pulmonary vascular resistance index in endotoxemic sheep . CONCLUSIONS: During ovine endotoxemia titrated terlipressin reversed hypotension but impaired the pulmonary circulation . The observed decrease in oxygen delivery may carry the risk of tissue hypoxia especially in sepsis, where oxygen demand is typically increased.

J Immunol, 2003 Mar 1, 170(5), 2734 - 41
Concomitant induction of CD4+ and CD8+ T cell responses in volunteers immunized with Salmonella enterica serovar typhi strain CVD 908-htrA; Salerno-Goncalves R et al.; Type 1 cell-mediated immunity might play an important role in protection from typhoid fever . We evaluated whether immunization with Salmonella enterica serovar Typhi (S . Typhi) strain CVD 908-htrA (a Delta aroC Delta aroD Delta htrA mutant), a leading live oral typhoid vaccine candidate, elicits specific CD4(+) and CD8(+) S . Typhi immune responses . Potent CTL responses and IFN-gamma secretion by CD8(+) T cells were detected following immunization with CVD 908-htrA in high (4.5 x 10(8) CFU) and low (5 x 10(7) CFU) dosages . S . Typhi-specific CTL were observed in six of eight vaccinees (four high and two low dose) after immunization . Mean increases in the frequency of IFN-gamma spot-forming cells (SFC) in the presence of S . Typhi-infected targets were 221 +/- 41 SFC/10(6) PBMC and 233 +/- 87 SFC/10(6) PBMC, in the high and low dose groups, respectively . Strong CD4(+) T cell responses were also observed . Increases in the IFN-gamma production to soluble S . Typhi flagella (STF) occurred in 82 and 38% of the volunteers who received the high and low doses, respectively . Robust correlations were observed between volunteers that responded with IFN-gamma SFC to stimulation with S . Typhi-infected cells and IFN-gamma released in response to stimulation with STF Ags (r = 0.822, p < 0.001) and between CTL and IFN-gamma production to STF (r = 0.818, p = 0.013) . These data demonstrating the concomitant induction of both CD4- and CD8-mediated CMI are consistent with a significant role for type 1 immunity in controlling typhoid infection and support the continuing evaluation of CVD 908-htrA as a typhoid vaccine candidate.

Int J Food Microbiol, 2003 May 15, 82(3), 245 - 53
Isolation of Salmonella from alfalfa seed and demonstration of impaired growth of heat-injured cells in seed homogenates; Liao CH et al.; Three major foodborne outbreaks of salmonellosis in 1998 and 1999 were linked to the consumption of raw alfalfa sprouts . In this report, an improved method is described for isolation of Salmonella from alfalfa seed lots, which had been implicated in these outbreaks . From each seed lot, eight samples each containing 25 g of seed were tested for the presence of Salmonella by the US FDA Bacteriological Analytical Manual (BAM) procedure and by a modified method applying two successive pre-enrichment steps . Depending on the seed lot, one to four out of eight samples tested positive for Salmonella by the standard procedure and two to seven out of eight samples tested positive by the modified method . Thus, the use of two consecutive pre-enrichment steps led to a higher detection rate than a single pre-enrichment step . This result indirectly suggested that Salmonella cells on contaminated seeds might be injured and failed to fully resuscitate in pre-enrichment broth containing seed components during the first 24 h of incubation . Responses of heat-injured Salmonella cells grown in buffered peptone water (BPW) and in three alfalfa seed homogenates were investigated . For preparation of seed homogenates, 25 g of seeds were homogenized in 200 ml of BPW using a laboratory Stomacher and subsequently held at 37 degrees C for 24 h prior to centrifugation and filtration . While untreated cells grew at about the same rate in BPW and in seed homogenates, heat-injured cells (52 degrees C, 10 min) required approximately 0.5 to 4.0 h longer to resuscitate in seed homogenates than in BPW . This result suggests that the alfalfa seed components or fermented metabolites from native bacteria hinder the repair and growth of heat-injured cells . This study also shows that an additional pre-enrichment step increases the frequency of isolation of Salmonella from naturally contaminated seeds, possibly by alleviating the toxic effect of seed homogenates on repair or growth of injured cells.

Int J Food Microbiol, 2003 May 15, 82(3), 213 - 21
Microbial quality of shrimp products of export trade produced from aquacultured shrimp; Mohamed Hatha AA et al.; Bacteriological quality of individually quick frozen (IQF) shrimp products produced from aquacultured tiger shrimp (Penaeus monodon) has been analysed in terms of aerobic plate count (APC), coliforms, Escherichia coli, coagulase-positive staphylococci, Salmonella, and Listeria monocytogenes . Eight hundred forty-six samples of raw, peeled, and deveined tail-on (RPTO), 928 samples of cooked, peeled, and deveined tail-on (CPTO), 295 samples of headless, undeveined shell-on (HLSO), and 141 samples of raw, peeled, and deveined tail-off (RPND) shrimps were analysed for the above bacteriological parameters . Salmonella was isolated in only one sample of raw, peeled tail-on . Serotyping of the strain revealed that it was S . typhimurium . While none of the cooked, peeled tail-on shrimp samples exceeded the aerobic plate count (APC) of 10(5) colony forming units per gram (cfu/g), 2.5% of raw, peeled, tail-on, 6.4% of raw, peeled tail-off, and 7.5% of headless shell-on shrimp samples exceeded that level . Coliforms were detected in all the products, though at a low level . Prevalence of coliforms was higher in headless shell-on (26%) shrimps followed by raw, peeled, and deveined tail-off (19%), raw, peeled tail-on (10%), and cooked, peeled tail-on (3.8%) shrimps . While none of the cooked, peeled tail-on shrimp samples were positive for coagulase-positive staphylococci and E . coli, 0.6-1.3% of the raw, peeled tail-on were positive for staphylococci and E . coli, respectively . Prevalence of staphylococci was highest in raw, peeled tail-off (5%) shrimps and the highest prevalence of E . coli (4.8%) was noticed in headless shell-on shrimps . L . monocytogenes was not detected in any of the cooked, peeled tail-on shrimps . Overall results revealed that the plant under investigation had exerted good process control in order to maintain superior bacteriological quality of their products.

Avian Pathol, 2002 Dec, 31(6), 589 - 92
Development of a lavage procedure to collect crop secretions from live chickens for studying crop immunity; Holt PS et al.; The crop (ingluvies), an organ for food storage in most avian species, is located at the base of the oesophagus . Previous work in our laboratory showed that, following infection with Salmonella enteritidis, significant anti-S . enteritidis antibody levels could be found in the crops of these birds . Samples in these previous studies were obtained by flushing the interiors of crops excised from killed birds, which is both labour and animal intensive . A method was sought that allowed multiple sampling of the same birds over time . We found that lavage fluid could be administered directly into the crop down the oesophagus using a narrow-diameter plastic tubing attached to a syringe, and the fluid could then be aspirated back into the syringe . Antibody-containing crop secretions could be collected with minimal discomfort to the test animals . In a study where birds were challenged with S . enteritidis, immunoglobulin A anti-S . enteritidis titres 3 weeks post-challenge were similar in crop samples obtained by live lavage versus the flushing of crops removed from killed birds . Such a sampling procedure may provide researchers with a simple method to follow mucosal immunity in chickens following infection or vaccination regimens.

Avian Pathol, 2002 Dec, 31(6), 581 - 7
Resistance of broiler outbred lines to infection with Salmonella enteritidis; Bolder NM et al.; Salmonella infections originating from poultry are one of the major causes of food-borne disease . For the control of salmonella in poultry a multifactorial approach is more likely to be effective, and the genetic resistance of poultry breeds to salmonella infections may be a valuable contribution . Experimental Salmonella enteritidis infections were examined in three different broiler outbred lines: the FC line, which had been selected for feed conversion efficiency; the R line, which had been selected for growth rate; and the C line, a commercially available line . The FC line had the highest mortality rate after intramuscular inoculation with 5 x 10(6) colony forming units (CFU) of S . enteritidis at 2 weeks of age (40% versus 21 and 20% in the other lines) . However, at slaughter age, the number of birds carrying salmonella in caecal contents, and the concentration of salmonella in the caecal contents, was lowest in the FC line . The FC and R lines were compared by inoculation with doses ranging from 10(2) to 10(7) CFU S . enteritidis . At sublethal doses (10(5) CFU or less), the FC line carried significantly less salmonella in caecal contents and the rate of systemic infection was lower . The start of shedding was also delayed compared with the R line . At doses of 10(6) CFU S . enteritidis or higher, there were no differences in salmonella carriage between the lines, and the FC line showed higher mortality . In conclusion, resistance to mortality and resistance to the carriage of S . enteritidis do not necessarily coincide within lines, as the FC line showed high mortality but low carriage, both in survivors of high infection doses and in all birds at lower infection doses.

Indian J Med Res, 2002 Aug, 116, 70 - 2
Typhidot test to detect IgG & IgM antibodies in typhoid fever; Jesudason M et al.; BACKGROUND & OBJECTIVES: As typhoid fever is endemic in India, there is a continuing search for a simple test which can be carried out in small laboratories for an early and rapid diagnosis . We have evaluated the Typhidot test for this purpose . METHODS: The Typhidot test was carried out on coded sera according to the manufacturer's instructions . The test was performed on 30 Widal positive sera, 30 sera from blood culture positive patients, 60 Widal negative sera and 30 samples from patients whose blood culture grew Gram negative bacilli (GNB) other than Salmonella Typhi . RESULTS: Typhidot test was positive for both IgG and IgM in 39 samples, IgM alone in 24 and IgG alone in 2 . Of the 30 culture positive samples, 27 were positive by Typhidot . The Typhidot test gave a sensitivity of 100 per cent and specificity of 80 per cent when bacteraemic patients were analysed . INTERPRETATION & CONCLUSION: The Typhidot is easy to perform, and requires no special equipment or training of staff for interpretation of results . It will be a useful complementary test to blood culture and the Widal test in the diagnosis of typhoid fever.

Berl Munch Tierarztl Wochenschr, 2003 Jan-Feb, 116(1-2), 55 - 8
Occurrence of Salmonellae in retail raw chicken products in Ethiopia; Tibaijuka B et al.; A cross-sectional study was undertaken to determine the presence and prevalence of salmonellae in retail raw chicken meat and giblets (gizzard and liver) in supermarkets in Addis Ababa (Ethiopia) . A total of 301 samples (244 chicken meat, 32 gizzards and 25 livers) were collected from 22 randomly selected supermarkets and examined for the presence of Salmonella . For the isolation and identification of salmonellae, the technique recommended by the International Organization for Standardization (ISO 6579, 1998) was used . Salmonellae were detected from 54 (17.9%) of the 301 samples examined . Chicken meat and giblet samples in 68.2% (15/22) of the supermarkets were contaminated with salmonellae . The contamination level of Salmonella was higher in chicken giblets as compared to chicken meat, which were respectively 12.3%, 53.1% and 28.0% in chicken meat, gizzard and liver samples . Out of the 54 Salmonella isolates, nine different serotypes were identified: Salmonella Braenderup (31.5%), S . Anatum (25.9%), S . Saintpaul (14.8%), S . Uganda (11.1%), S . Haifa, S . Group B, S . Rough form and S . Typhimurium (each 3.7%) and S . Virchow (1.8%) . The high level of Salmonella contamination of chicken meat and giblets observed in the present study indicated the need in an improvement in the microbiological quality of retail chicken in Ethiopia.

J Exp Med, 2003 Feb 17, 197(4), 527 - 35
Low penetrance, broad resistance, and favorable outcome of interleukin 12 receptor beta1 deficiency: medical and immunological implications; Fieschi C et al.; The clinical phenotype of interleukin 12 receptor beta1 chain (IL-12Rbeta1) deficiency and the function of human IL-12 in host defense remain largely unknown, due to the small number of patients reported . We now report 41 patients with complete IL-12Rbeta1 deficiency from 17 countries . The only opportunistic infections observed, in 34 patients, were of childhood onset and caused by weakly virulent Salmonella or Mycobacteria (Bacille Calmette-Guerin -BCG- and environmental Mycobacteria) . Three patients had clinical tuberculosis, one of whom also had salmonellosis . Unlike salmonellosis, mycobacterial infections did not recur . BCG inoculation and BCG disease were both effective against subsequent environmental mycobacteriosis, but not against salmonellosis . Excluding the probands, seven of the 12 affected siblings have remained free of case-definition opportunistic infection . Finally, only five deaths occurred in childhood, and the remaining 36 patients are alive and well . Thus, a diagnosis of IL-12Rbeta1 deficiency should be considered in children with opportunistic mycobacteriosis or salmonellosis; healthy siblings of probands and selected cases of tuberculosis should also be investigated . The overall prognosis is good due to broad resistance to infection and the low penetrance and favorable outcome of infections . Unexpectedly, human IL-12 is redundant in protective immunity against most microorganisms other than Mycobacteria and Salmonella . Moreover, IL-12 is redundant for primary immunity to Mycobacteria and Salmonella in many individuals and for secondary immunity to Mycobacteria but not to Salmonella in most.

J Bacteriol, 2003 Mar, 185(5), 1659 - 71
Overexpression of the waaZ gene leads to modification of the structure of the inner core region of Escherichia coli lipopolysaccharide, truncation of the outer core, and reduction of the amount of O polysaccharide on the cell surface; Frirdich E et al.; The waa gene cluster is responsible for the biosynthesis of the lipopolysaccharide (LPS) core region in Escherichia coli and Salmonella: Homologs of the waaZ gene product are encoded by the waa gene clusters of Salmonella enterica and E . coli strains with the K-12 and R2 core types . Overexpression of WaaZ in E . coli and S . enterica led to a modified LPS structure showing core truncations and (where relevant) to a reduction in the amount of O-polysaccharide side chains . Mass spectrometry and nuclear magnetic resonance spectroscopy were used to determine the predominant LPS structures in an E . coli isolate with an R1 core (waaZ is lacking from the type R1 waa gene cluster) with a copy of the waaZ gene added on a plasmid . Novel truncated LPS structures, lacking up to 3 hexoses from the outer core, resulted from WaaZ overexpression . The truncated molecules also contained a KdoIII residue not normally found in the R1 core.

Vet Microbiol, 2003 May 2, 93(1), 73 - 8
Identification of glycosphingolipid binding sites for SEF21-fimbriated Salmonella enterica serovar Enteritidis in chicken oviductal mucosa; Li W et al.; In order to clarify the presence of glycosphingolipids (GSLs) receptors for Salmonella enterica serovar Enteritidis with SEF21 fimbriae, we analyzed neutral GSLs and gangliosides from chicken oviductal mucosa and investigated the binding of bacteria to neutral GSLs and gangliosides . Five types of neutral GSLs, designated as N-1 to N-5, and two types of gangliosides, designated as G-1 and G-2, were identified on the thin-layer chromatography (TLC) plates . In the bacterial binding assay on TLC, the fimbriated bacteria bound only to glucosylceramide (GlcCer) standard, N-1 having the same TLC mobility as GlcCer, GM3 standard and G-1 corresponding to GM3 in TLC mobility, but not to N-2, N-3, N-4, N-5, or G-2 . These results suggest the presence of GlcCer (N-1) and ganglioside GM3 (G-1) on the epithelial surface of chicken oviductal tract which act as sites for adherence of SEF21-fimbriated S . Enteritidis .

Oral Microbiol Immunol, 2003 Feb, 18(1), 14 - 23
Contrasting responses of human gingival and periodontal ligament fibroblasts to bacterial cell-surface components through the CD14/Toll-like receptor system; Hatakeyama J et al.; We compared human periodontal ligament fibroblasts with human gingival fibroblasts isolated from the same donor to examine interleukin-8 (IL-8) responses of the cells to Salmonella lipopolysaccharide, a water-soluble peptidoglycan from Staphylococcus epidermidis and the synthetic muramyldipeptide, with special reference to the possible involvement of the CD14/Toll-like receptor (TLR) system of the cells in the responses . Human gingival fibroblasts expressed CD14 on their surfaces and strongly expressed CD14 mRNA, while human periodontal ligament fibroblasts showed considerably lower levels of expression in both respects . Both cells expressed mRNA of TLR-related molecules, i.e . TLR2, TLR4, MD-2 and MyD88, although human periodontal ligament fibroblasts expressed TLR2 more strongly than human gingival fibroblasts . Human gingival fibroblasts exhibited a stronger IL-8 response than human periodontal ligament fibroblasts to lipopolysaccharide, while human periodontal ligament fibroblasts exhibited a response comparable to, or slightly stronger than, that of human gingival fibroblasts to S . epidermidis peptidoglycan and muramyldipeptide . The IL-8 responses of both cells to lipopolysaccharide and S . epidermidis peptidoglycan were completely inhibited by antihuman CD14 monoclonal antibody (MAb) . The responses of both cells to lipopolysaccaride were significantly inhibited by antihuman TLR4 MAb, while those to S . epidermidis peptidoglycan were inhibited by antihuman TLR2 MAb . In contrast, muramyldipeptide activated both types of cells in a TLR2- and TLR4-independent manner, although the activities of muramyldipeptide on human gingival fibroblasts, but not human periodontal ligament fibroblasts, were significantly inhibited by anti-CD14 MAb.

Clin Microbiol Infect, 2003 Feb, 9(2), 149 - 52
Resistance to beta-lactams among blood isolates of Salmonella spp . in European hospitals: results from the SENTRY Antimicrobial Surveillance Program 1997-98; Tzouvelekis LS et al.; The susceptibility to beta-lactams and the beta-lactamase content of 110 Salmonella spp . blood isolates collected during 1997-98 in 19 European centers participating in the SENTRY Surveillance Program were studied . Thirty-one isolates (28%) were resistant to penicillins, due to production of TEM-1 (27 isolates), OXA-1 (three isolates) or TEM-1 + OXA-1 (one isolate) . All OXA-1 producers and 10 TEM-1-producing isolates were also resistant to penicillin-clavulanic acid combinations . In the latter isolates, this phenotype was associated with increased production of TEM-1 . Sixteen TEM-1-producing Salmonella Enteritidis isolates and one OXA-1-producing S . Typhimurium isolate were able to transfer beta-lactam resistance by conjugation.

Chem Res Toxicol, 2003 Feb, 16(2), 216 - 26
Glutathione transferase theta 1-1-dependent metabolism of the water disinfection byproduct bromodichloromethane; Ross MK et al.; Bromodichloromethane (CHBrCl(2)), a prevalent drinking water disinfection byproduct, was previously shown to be mutagenic in Salmonella that express rat GSH transferase (GST) theta 1-1 (GST T1-1) . In the present study, in vitro experiments were performed to study the kinetics of CHBrCl(2) reactions mediated by GST in different species as well as the isoform specificity and reaction products of the GST pathway . Conjugation activity of CHBrCl(2) with GSH in mouse liver cytosol was time- and protein-dependent, was not inhibited by the GST alpha, mu and pi inhibitor S-hexyl-GSH, and correlated with GST T1-1 activity toward the substrate 1,2-epoxy-3-(4'-nitrophenoxy)propane . Conjugation activities in hepatic cytosols of different species toward CHBrCl(2) followed the order mouse > rat > human . As compared with CH(2)Cl(2), the catalytic efficiency (k(cat)/K(m)) of conjugation of CHBrCl(2) with GSH by pure recombinant rat GST T1-1 was approximately 3-6-fold less . Taken together, this suggests that GST T1-1 is the primary catalyst for conjugation of CHBrCl(2) with GSH and that flux through this pathway is less than for CH(2)Cl(2) . The initial GSCHCl(2) conjugate formed was unstable and degraded to several metabolites, including GSCH(2)OH, S-formyl-GSH, and HCOOH . Addition of NAD(+) to cytosol did not alter the rate of conjugation of CHBrCl(2) with GSH; however, it did increase the amount of {(14)C}HCOOH produced ( approximately 10-fold) . A similar result was seen in a reaction containing pure rat GST T1-1 and GSH-dependent formaldehyde dehydrogenase, indicating that GSCH(2)OH was formed as a precursor to S-formyl-GSH . The half-life of synthetic S-formyl-GSH in pH 7.4 buffer was approximately 1 h at ambient temperature and decreased to approximately 7 min in pH 9.0 buffer, and it does not react with deoxyguanosine . In conclusion, GST T1-1 conjugation of CHBrCl(2) has been definitively demonstrated and the kinetics of conjugation of CHBrCl(2) with GSH characterized in mouse, rat, and human hepatic cytosols . The significance of this GST pathway is that reactive GSH conjugates are produced resulting in possible formation of DNA adducts . Comparisons with CH(2)Cl(2) suggest that the reactive intermediates specific to GSH conjugation of CHBrCl(2) are more mutagenic/genotoxic than those derived from CH(2)Cl(2).

Braz J Infect Dis, 2002 Dec, 6(6), 281 - 7 Epub 2003 Nov 03.
Sensitivity pattern of Salmonella serotypes in Northern India; Gautam V et al.; BACKGROUND: Enteric fever continues to be a major public health problem, especially in the developing countries of the tropics . We determined the incidence of Salmonella bloodstream infections and their antimicrobial resistance patterns from May to August in the years 1997-2001 in Haryana, a large state of India . The minimum inhibitory concentration (MIC) was also determined for 60 isolates of S . typhi to various commonly used antimicrobial agents . MATERIAL AND METHODS: Blood cultures of 6,956 patients (PUO/septicemia) were processed by standard procedures and the Salmonella spp . isolates were identified with specific antisera and with standard biochemical tests . Antimicrobial susceptibilities were determined by Stokes disc diffusion method . The MIC of 60 randomly isolated strains of S . typhi was determined by agar dilution method using Mueller Hinton Agar medium . RESULTS: Isolation rates of Salmonella spp . increased in 2000 and 2001 . Multidrug resistance (MDR) in S . typhi had increased while in S . paratyphi it had decreased markedly . Ninety per cent chloramphenicol sensitivity was seen in S . typhi by MIC method . There was a decrease in the susceptibility to ciprofloxacin of S . typhi with MIC showing an upward trend . All S . typhi tested were sensitive to third generation cephalosporins and aminoglycosides with MIC well below the breakpoint . DISCUSSION: Our study indicates that MDR in S . typhi is on the rise in our area . There is also re-emergence of chloramphenicol sensitivity . Rising MIC values of ciprofloxacin may lead to prolonged treatment, delayed recovery or pose treatment failure . Thus, sensitivity pattern of causative organism must be sought before instituting appropriate therapy to prevent further emergence of drug resistance.

FEMS Microbiol Lett, 2003 Jan 21, 218(1), 127 - 33
Growth and colonization suppression of Salmonella enterica serovar Hadar in vitro and in vivo; Nogrady N et al.; Growth suppression in Salmonella enterica serovar Hadar (S . Hadar) was investigated, in vitro under strict anaerobiosis and in vivo in the intestine of the day-old chicken . Stationary-phase cultures of 20 S . Hadar field strains were tested against each other for growth suppression activity by their ability to suppress the multiplication of low counts of minority cultures inoculated into them as nalidixic acid-resistant mutants . All strains showed profound growth suppression . Four S . Hadar strains were selected and further tested for their ability to suppress growth of S . Enteritidis, S . Typhimurium, S . Virchow and S . Saintpaul . One of the four strains (S . Hadar 18) was randomly selected for further studies . Precolonization of chicken with S . Hadar 18 prevented superinfection with any of the serovars mentioned above . From more than 1000 TnphoA mutants of S . Hadar 18 screened against the parent strain anaerobically in vitro, four were non-suppressive with TnphoA insertions in dapF, aroD, sgaT or tatA . Only the dapF mutant was also non-suppressive in the chicken intestine.

Indian J Pathol Microbiol, 2000 Jan, 43(1), 17 - 22
Salmonella 3, 10:r: toxicity in rabbit ileum and liver by light and electron microscopy; Yashroy RC; Salmonella 3, 10:r:- (a monophasic variety of otherwise diphasic serotypes such as S . weltevreden and S . simi) Cell_free filtrate, when introduded into rabbit ligated ileal loops causes fluid exsorption, as studied 18-hr after treatment . Light microscopic histology of treated ileum shows denudation of the columnar epithelium at several places, thereby allowing the passage of the toxic principle into circulation . An important target organ, liver shows extensive centrilobular necrosis, as observed by light microscopy . Transmission electron microscopy of ileum reveals opening of membrane junctions between the adjacent cells of epithelial lining of the treated ileum at places, and focal devitalization including formation of intra-cellular membranous inclusinos . Electron microscopy of liver shows extensive damage and swelling of cytoplasmic membranes . However, the areas of darkly staining lamellae of granulated endoplasmic reticulum are also seen in stacks as will as dispersed . These studies stress that Salmonella toxic substances can cause extensive damage to intestine and liver both.

Rev Esp Quimioter, 2002 Mar, 15(1), 55 - 60
{Serotypes and antibiotic susceptibility of the genus Salmonella in Elche, Spain}; Sirvent E et al.; Salmonellosis is one of the main public health problems in developed countries . The most common serotype is Salmonella enteritidis, followed by S . typhimurium, S . hadar and S . virchow . Each serotype's sensitivity to antibiotics is different, but in general, there has been an increase in the number of isolates resistant to antibiotics . This is especially true for S . hadar and nalidixic acid, although we have not isolated any strains resistant to ciprofloxacin . Our study provides data that may help to control these infections and draws attention to the increase in resistance to certain antibiotics . This should give rise to the implementation of measures to protect public health and control the use of antibiotics, especially in animals.

Lett Appl Microbiol, 2003, 36(3), 152 - 6
Detection of Salmonella by indicator agar media and PCR as affected by alfalfa seed homogenates and native bacteria; Liao CH et al.; AIMS: To investigate and prevent the undesirable effect of native bacteria and alfalfa seed homogenates on detection of Salmonella in alfalfa seeds by indicator agar media and polymerase chain reaction (PCR) . METHODS AND RESULTS: The relative sensitivity of five indicator agar media, including modified semisolid RV (MSRV), xylose-lysine-Tergitol 4 (XLT4), Hektoen enteric agar (HEA), brilliant green agar (BGA) and bismuth sulphite agar (BSA), for detection of Salmonella in the presence of a large number of native bacteria from alfalfa seeds was examined . The detection limit as measured by the ratio between the numbers of native bacteria and Salmonella was estimated to be 10(6) to 1 for MSRV and 10(3) to 1 for XLT4, HEA, BGA or BSA . Presence of alfalfa seed homogenates markedly reduced the sensitivity of Salmonella detection by PCR . The minimal number of Salmonella detectable by PCR was determined to be 1-10 and 100-1000 CFU in the absence and presence of seed homogenate, respectively . Application of anti-Salmonella immunomagnetic beads permitted detection of 2-5 CFU of heat-injured cells in 25 g of seeds within 24 h by PCR . CONCLUSIONS: The MSRV medium is more sensitive than other indicator agars for detecting a small number of motile Salmonella in samples containing a large number of native bacteria . Application of immunomagnetic beads eliminates the PCR-inhibitory activity of seed homogenates and improves the detection of Salmonella in inoculated seeds . SIGNIFICANCE AND IMPACT: The results generated from this study will aid the seed distributors, sprout growers and public health officials to identify and recall the Salmonella-contaminated seed lots to be used for sprout production.

Cell Microbiol, 2003 Feb, 5(2), 123 - 32
Bordetella type III secretion induces caspase 1-independent necrosis; Stockbauer KE et al.; The Bordetella bronchiseptica type III (TIII) secretion system induces cytotoxicity in infected macrophages and epithelial cells . In this report we characterize the cell death phenotype and compare it to the TIII-dependent cytotoxicity induced by Yersinia enterocolitica and Shigella flexneri . Bordetella bronchiseptica strain RB58 was able to induce cell death in J774A.1 macrophages with the same efficiency as Shigella and Yersinia, but only B . bronchiseptica was able to kill epithelial cells in a TIII-dependent manner . Primary macrophages from caspase 1-/- mice were susceptible to RB58-mediated killing, suggesting that unlike Shigella and Salmonella, caspase 1 does not mediate cell death . RB58-induced cytotoxicity was not inhibited by addition of the pan-caspase inhibitor zVAD, and Western blot analyses of RB58-infected HeLa cells indicated that neither caspase 3 nor 7 was cleaved and PARP remained in its full-length active form . Morphologically the RB58-infected HeLa cells resembled necrotic rather than apoptotic cells, exhibiting cytoplasmic swelling and extensive membrane blebbing in the absence of nuclear changes . The addition of exogenous glycine, which has been shown to prevent necrotic cell death by blocking non-specific ion fluxes across the plasma membrane, blocked RB58-induced cytotoxicity . Addition of cyclosporin A which prevents the opening of the mitochondrial permeability pore, had no effect on RB58-infected cells . We conclude that the B . bronchiseptica TIII secretion system induces a mode of cell death consistent with necrosis that is distinct from that of Yersinia and Shigella.

Poult Sci, 2003 Jan, 82(1), 67 - 70
Detection of Salmonella enteritidis-specific immunoglobulin A antibodies in crop samples from chickens infected with Salmonella enteritidis; Seo KH et al.; The crop (ingluvies), an organ for food storage in most avian species when the proventriculus is full, is located at the base of the esophagus . Little is known about any immunological capacity in the crop, and the current study was conducted to determine whether any antibodies to SE could be found in crop flushes taken from White Leghorn hens following infection with this organism . Surprisingly, an exceptionally strong IgA anti-SE response could be detected in the crops of hens 17 d postchallenge, and a comparison at Day 22 of crop vs . intestinal IgA anti-SE responses showed a good correlation between anti-SE antibody levels in the two regions . Histologic examination of crop tissues revealed development of lymphoid aggregates in the crop walls following challenge with SE . These results indicate that the crop may serve a role in immune protection in addition to its capacity as a food storage organ.

J Vet Med Sci, 2003 Jan, 65(1), 117 - 9
Adjuvant effects of sugar cane extracts (SCE) in chickens; El-Abasy M et al.; The effects of sugar cane extracts (SCE) on immune responses in chickens were studied . Two- or 10-month-old chickens orally administered SCE (500 mg/kg/day), for 3 consecutive days before immunized with sheep red blood cells, Brucella abortus and Salmonella Enteritidis organisms, showed significantly increased and prolonged antibody responses to these antigens, compared to control chickens without SCE . Furthermore, chickens orally administered SCE also revealed enhanced delayed type hypersensitivity responses to human gamma globulin . These results indicated that SCE has immunostimulating and adjuvant effects in chickens.

Appl Environ Microbiol, 2003 Feb, 69(2), 1075 - 81
Molecular analyses of Salmonella enterica isolates from fish feed factories and fish feed ingredients; Nesse LL et al.; Isolates of the most commonly observed salmonella serovars in Norwegian fish feed factories from 1998 to 2000 (Salmonella enterica serovar Agona, S . enterica serovar Montevideo, S . enterica serovar Senftenberg, and S . enterica serovar Kentucky) were studied by pulsed-field gel electrophoresis (PFGE) and plasmid profile analysis and compared to isolates of the same serovars from fish feed ingredients, humans, and other sources (a total of 112 isolates) . Within each serovar, a variety of distinct PFGE types (with similarity levels less than 90%) were observed in the feed ingredients and other sources, while only two distinct types of each serovar were identified in the factories . The combined results of PFGE and plasmid analyses showed that each factory harbored only a few S . enterica clones . Some of these clones persisted for at least 3 years in the factories, indicating that there was long-lasting contamination probably due to inadequate decontamination procedures.

Int J Food Microbiol, 2003 Apr 25, 82(2), 97 - 103
Incidence of Salmonella from poultry products and their susceptibility to antimicrobial agents; Antunes P et al.; The incidence of Salmonella in 60 samples of poultry products of national origin available for consumers obtained from two local butcher shops and one canteen of the city of Porto and the susceptibility to antimicrobial agents allowed for human or animal therapy were evaluated . The results show that poultry samples are frequently contaminated with Salmonella (60%), belonging to 10 different serotypes . Salmonella enteritidis and S . hadar were the most prevalent serotypes . In addition, a high number (75%) of the Salmonella isolates was resistant to one or more antimicrobial agents and eight different resistance profiles were recorded . Resistance to nalidixic acid and enrofloxacin was demonstrated for 50% of the isolates and the occurrence of resistant and multiresistant S . enteritidis isolates were less frequent than for S . hadar . This study suggests a high incidence of Salmonella on Portuguese poultry products and shows that they could be a potential vehicle of resistant Salmonella foodborne infections.

Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi, 2000, 18(4), 193 - 6
{Inducible expression of MSP1 gene of Plasmodium falciparum by a tetracycline-controlled promoter}; Qian F et al.; OBJECTIVE: To express the entire MSP1 gene of Plasmodium falciparum and its C-terminal 42 kDa fragment using a tetracycline-controlled PLtetO-1 promoter . METHODS: The entire MSP1 gene and 42 kDa fragment gene were cloned into the plasmid of pZE11, and transformed into E . coli DH5 alpha Z1 . Restriction enzyme analysis, SDS-PAGE and Western blotting were used to examine two recombinant plasmids and their expression in E . coli DH5 alpha Z1 . RESULTS: The recombinant plasmids of pZE11/MSP1 and pZE11/MSP1-42 were constructed successfully . The expressive products about 190 kDa and 42 kDa of two genes in E . coli DH5 alpha Z1 were identified by SDS-PAGE and Western blotting . CONCLUSION: Tightly controlling expression of the MSP1 gene in E . coli is essential to reduce the toxicity of the product to its host cells as well as to provide a feasibility to construct Salmonella vaccine strain which can inducibly express the important malarial vaccine candidate gene.

Commun Dis Public Health, 2002 Dec, 5(4), 301 - 4
Collaborative investigation of an outbreak of Salmonella enterica serotype Newport in England and Wales in 2001 associated with ready-to-eat salad vegetables; Ward LR et al.; In June 2001, as part of a microbiological study of bagged, ready-to-eat salad products, Salmonella enterica serotype Newport was isolated from a sample of pre-packed green salad distributed by a major supermarket retailer . The strain was characterised by phage typing, plasmid profile typing and pulsed-field gel electrophoresis . Other isolates of S . Newport from cases of human infection in England and Wales in the first six months of 2001 were similarly characterised . Of 60 strains from cases of human infection, 19 were found to be indistinguishable from that isolated from the salad product . This study highlights the benefits of an integrated approach to outbreak investigations, involving the various elements of the PHLS and the Food Standards Agency, and acknowledges the full co-operation of the retailer in ensuring the rapid withdrawal of the contaminated product.

Mem Inst Oswaldo Cruz, 2002 Dec, 97(8), 1153 - 6 Epub 2003 Jan 20.
Detection of hilA gene sequences in serovars of Salmonella enterica subspecies enterica; Cardona-Castro N et al.; hilA gene promoter, component of the Salmonella Pathogenicity Island 1, has been found in Salmonella serovar Typhimurium, being important for the regulation of type III secretion apparatus genes . We detected hilA gene sequences in Salmonella serovars Typhi, Enteritidis, Choleraesuis, Paratyphi A and B, and Pullorum, by polymerase chain reaction (PCR) and hybridization techniques . The primers to carry out PCR were designed according to hilA sequence . A low stringency hybridization with the probe pVV441 (hilA open-reading-frame plasmid) was carried out . To find hilA gene sequences in other Salmonella sp . suggest that these serovars could have similar sequences of this kind of virulence genes.

Arq Neuropsiquiatr, 2002 Dec, 60(4), 1034 - 7 Epub 2003 Jan 15.
{Spontaneous cervical spondylodiscitis caused by Salmonella typhi in an immunocompetent patient}; Falavigna A et al.; We report a case of spontaneous cervical spondylodiscitis caused by Salmonella typhi . A 52-year-old man presented in the neurosurgical service with complaints of pain in the cervical and scapular region . Cervical inflammatory disease was suggested by bone scintigraphy and magnetic resonance imaging . The diagnosis of Salmonella typhi spondylodiscitis was established by blood culture and culture of needle biopsy specimen taken from the C5 vertebra . The agglutinin titers for Salmonella were elevated . Intravenous ciprofloxacin therapy and external immobilization with a halo vest were instituted . A review of literature was performed evaluating the clinical, diagnostic and therapeutic aspects of this unusual pathology.

J Bacteriol, 2003 Feb, 185(4), 1459 - 61
2-aminopurine allows interspecies recombination by a reversible inactivation of the Escherichia coli mismatch repair system; Matic I et al.; 2-Aminopurine treatment of Escherichia coli induces a reversible phenotype of DNA mismatch repair deficiency . This transient phenotype results in a 300-fold increase in the frequency of interspecies conjugational recombination with a Salmonella enterica serovar Typhimurium Hfr donor . This method can be used for the generation of biodiversity by allowing recombination between diverged genes and genomes.

J Bacteriol, 2003 Feb, 185(4), 1357 - 66
Detection of other microbial species by Salmonella: expression of the SdiA regulon; Smith JN et al.; Salmonella, Escherichia, and Klebsiella do not encode any recognized type of N-acylhomoserine lactone (AHL) synthase, and consistent with this, they do not synthesize AHLs under any conditions tested . However, they do encode an AHL receptor of the LuxR family, named SdiA . MudJ fusions in four loci are known to respond to plasmid-encoded sdiA in Salmonella, but only the rck locus has been described . Here we report the location and sequence analysis of the remaining three loci . The srg-6::MudJ is within gtgA of the gifsy-2 prophage, and the srg-7::MudJ is within PSLT61 of the virulence plasmid . Both fusions are in the antisense orientation . The third fusion, srgE5::MudJ, is within a horizontally acquired gene of unknown function at 33.6 centisomes that we have named srgE . Previously, sdiA expressed from its natural position in the chromosome was demonstrated to activate a plasmid-based transcriptional fusion to the rck promoter in response to AHL production by other bacterial species . However, the MudJ fusions did not respond to chromosomal sdiA . Here we report that MudJ fusions to three of the four loci (not srg-6) are activated by AHL in an sdiA-dependent manner during growth in motility agar (0.25% agar) but not during growth in top agar (0.7% agar) or on agar plates (1.2% agar) . In motility agar, the srgE promoter responds to sdiA at 30 degrees C and higher while the rck and srg-7 promoters respond only at 37 or 42 degrees C . Substantial AHL-independent SdiA activity was observed at 30 degrees C but not at 37 degrees C.

J Bacteriol, 2003 Feb, 185(4), 1190 - 4
Effect of intracellular pH on rotational speed of bacterial flagellar motors; Minamino T et al.; Weak acids such as acetate and benzoate, which partially collapse the transmembrane proton gradient, not only mediate pH taxis but also impair the motility of Escherichia coli and Salmonella at an external pH of 5.5 . In this study, we examined in more detail the effect of weak acids on motility at various external pH values . A change of external pH over the range 5.0 to 7.8 hardly affected the swimming speed of E . coli cells in the absence of 34 mM potassium acetate . In contrast, the cells decreased their swimming speed significantly as external pH was shifted from pH 7.0 to 5.0 in the presence of 34 mM acetate . The total proton motive force of E . coli cells was not changed greatly by the presence of acetate . We measured the rotational rate of tethered E . coli cells as a function of external pH . Rotational speed decreased rapidly as the external pH was decreased, and at pH 5.0, the motor stopped completely . When the external pH was returned to 7.0, the motor restarted rotating at almost its original level, indicating that high intracellular proton (H+) concentration does not irreversibly abolish flagellar motor function . Both the swimming speeds and rotation rates of tethered cells of Salmonella also decreased considerably when the external pH was shifted from pH 7.0 to 5.5 in the presence of 20 mM benzoate . We propose that the increase in the intracellular proton concentration interferes with the release of protons from the torque-generating units, resulting in slowing or stopping of the motors.

J Periodontal Res, 2003 Feb, 38(1), 36 - 43
Effects of CD14 receptors on tissue reactions induced by local injection of two gram-negative bacterial lipopolysaccharides; Chiang CY et al.; Lipopolysaccharide (LPS) was recognized by CD14, which may be an important mediator in the deleterious effects of LPS on the periodontal destruction . To investigate the roles of CD14 molecules on LPS-induced soft tissue inflammation and bone destruction, the tissues of CD14-deficient mice were examined histopathologically following a local injection of either Salmonella minnesota or Porphyromonas gingivalis LPS . In the first group, 12 mice received a local injection of 500 microg of purified P . gingivalis LPS and six mice were injected with saline to the calvaria as controls . In the second group 13 mice were injected subcutaneously on the laterally abdominal skin with 50 microg of S . minnesota LPS and three mice were injected with PBS . Mice were sacrificed at day 5 . After histological preparation, the tissue sections of calvaria and soft tissue specimen were stained with tartrate-resistant acid phosphatase (TRAP) marker for osteoclast and macrophage . The soft tissue sections were also stained with hematoxylin & eosin (H&E) . Resorption surface and osteoclast index were measured to quantify bone resorption . Necrotic area and inflammatory cell numbers were estimated to assess the situation of local inflammation . Our results indicated that LPS-induced bone resorption is inhibited in CD14-deficient mice . An increase in the number of total inflammatory cells was noticed in both CD14-deficient mice and wild-type mice; however, the cell numbers were less in CD14-deficient mice than those in wild-type mice (two- to three-fold decrease) . Therefore, we conclude that the LPS-stimulated bone resorption is mainly via CD14 receptor but the LPS-induced soft tissue inflammation appears to be partially dependent on the receptor.

Environ Microbiol, 2003 Feb, 5(2), 79 - 84
Persistence of Salmonella enteritidis phage type 4 in the environment and arthropod vectors on an empty free-range chicken farm; Davies RH et al.; The persistence of S . Enteritidis PT4 was studied on a free-range breeding chicken farm which had been depopulated following identification of the organism in breeding birds . The site was sampled periodically for 26 months after depopulation and the organism was found to persist in litter, dried faeces and feed, but not in dust within empty poultry houses, for the whole of that period . Salmonella Enteritidis PT4 was also found in soil samples after 8 months but not 13 months and in faeces from wild mice, foxes and cats but not wild birds or badgers . The organism was also found in adult and larval forms of ground beetles and centipedes . Addition of pullets to a contaminated pen or inclusion of contaminated litter, feed or beetles/larvae to feed did not result in acquisition of infection by birds.

Indian J Pediatr, 2002 Dec, 69(12), 1029 - 32
Bacteraemia in children; Sharma M et al.; OBJECTIVES: (i)To know the etiology of bacteraemia in children, (ii) To learn the antibiotic sensitivity pattern of the isolates . METHOD: Over the period of thirteen months 4,368 blood samples (for blood culture) were collected from children in the age group of 0 day-14 years, suspected of having fever and sepsis . Blood samples were collected for blood culture from each case . Organisms were isolated and identified by conventional methods . Antibiotic susceptibility for each isolate was determined by using modified Stokes method . RESULT: 1,001 cases (22.9%) were culture positive . Incidence of bacteraemia in neonates was 521(33.94%) . Gram negative organisms were the most predominant isolates (88.8%) . Commonest was Klebsiella 471 (47.1%) followed by Salmonella sp . 162 (16.2%) and Pseudomonas 80 (8%) whereas in gram positive, Staphylococcus aureus 76 (7.6%) was the most common . Maximum sensitivity was seen by sulbactum/cefaperazone combination-969 (98.2%) by all isolates . Linezolid 97 (99.0%) was the most sensitive drug for gram positive isolates . CONCLUSION: Gram negative multidrug resistant organisms were the main cause of septicemia in all the age groups . Therefore great caution is required in selection of antibiotic therapy.

Br Poult Sci, 2002 Dec, 43(5 Suppl), 653 - 61
Identification and quantification of granulocytes in caecal mucosa and submucosa of chickens experimentally infected with Eimeria tenella and Salmonella enteritidis; Petrone VM et al.; 1 . Poultry granulocytes are not clearly distinguished from each other with haematoxylin-eosin (HE) stain; thus, histochemical techniques must be used . Three experiments were carried out using 4-week-old Leghorn chickens . 2 . Three, 80-chicken groups were orally infected with (1) 10(8) colony forming units (CFUs) Salmonella enteritidis, or (2) 10(4) Eimeria tenella oocysts, or (3) 10(8) CFUs S . enteritidis + 10(4) E . tenella oocysts . Ten chickens from each group were euthanased and caecum samples obtained . Caecum samples were fixed in 10% formalin (buffered, pH 7.4) at 4, 8, 12 h, 1, 3, 5, 7, and 14 d post-inoculation (PI) . 3 . Samples were stained using three different staining techniques: HE for the identification of heterophils and eosinophils, Ziehl-Neelsen for mast cells, and p-phenilenediamine dihydrochloride plus pyrocatechol (PPD + PC) for eosinophils . 4 . Birds from Experiment 1 showed no changes in the numbers of granulocytes . Birds from Experiments 2 and 3 showed higher numbers of heterophils in caecal mucosa and submucosa separately, on d 5 and 7 . In Experiment 3, a decrease was observed in submucosal mast cells on d 3 . Chickens from Experiments 2 and 3 showed increased numbers of mucosal mast cells between d 7 and 14 . 5 . PPD + PC positively stained eosinophils, but not heterophils . 6 . Numbers of heterophils and mast cells were increased during the acute inflammatory process caused by E . tenella . Therefore, mast cells could play a role as primary inflammatory cells . Eosinophils seem not to be part of the inflammatory process caused by E . tenella.

Wei Sheng Wu Xue Bao, 1999 Dec, 39(6), 533 - 8
{Stable expression and immunogenicity in a attenuated Salmonella typhi strain of coli surface antigen-6 of enterotoxigenic Escherichia coli}; Teng J et al.; A gene fragment encoding for surface antigen CS6 of enterotoxigenic of Escherichia coli has been cloned into the plasmid pXL670, a new recombinant plasmid pSS64 was obtained by transforming E . coli X6097 with asd gene deletion . A safe and effective E . coli/S . typhi bivalent candidate vaccine was constructed by introducing pSS64 into delta aroA, delta aroC, delta asd Salmonella typhi . The vaccine strain is still stable in the absence of antibiotics . Animal tests demonstrated that this strain, when administered subcutaneously in mice, could provide significant protection against the intraperitoneal challenge from wild S . typhi Ty2 . Immunization of rabbit with this strain raised specific antibody responses against CS6 and Vi antigen of S . typhi . This study lays the foundation for the construction of a new E . coli/S . typhi bivalent live oral vaccine.

Vet Microbiol, 2003 Apr 29, 92(4), 379 - 88
Comparison of Salmonella enterica serovar Abortusequi isolates of equine origin by pulsed-field gel electrophoresis and fluorescent amplified-fragment length polymorphism fingerprinting; Akiba M et al.; Equine paratyphoid is caused by Salmonella enterica serovar Abortusequi, and manifests mainly as abortion in the mare . We compared S . Abortusequi strains isolated in Japan and other countries using pulsed-field gel electrophoresis (PFGE) and fluorescent amplified-fragment length polymorphism (FAFLP) analysis . PFGE analysis of S . Abortusequi strains gave 21-27 fragments ranging in size from 33 to 602kb . Although two PFGE profiles were observed among the 20 S . Abortusequi isolates in Japan, the restriction fragments originating from the chromosome were common between the two profiles . The similarity index of the two profiles was 90.9%, while those between Japanese and five other S . Abortusequi strains were 29.8-37.5% . On the other hand, FAFLP analysis of S . Abortusequi strains generated 64-67 amplified fragments ranging in size from 100 to 400bp . One polymorphic fragment was observed among the 20 S . Abortusequi isolates in Japan . These data indicate the close relation of this agent in Japan . S . Abortusequi strains sharing a common ancestry might have been conserved in Japan.

Acta Histochem, 2002, 104(4), 435 - 9
T lymphocyte subpopulations and B lymphocyte cells in caecum and spleen of chicks infected with Salmonella enteritidis; Asheg A et al.; The effect of low and high doses of Salmonella enteritidis PT4 (SE) on immunocompetent cells in caecum and spleen of one-day-old chicks was investigated . Subsets of T lymphocytes positive for CD3, CD4, CD8 and B lymphocytes (Bu1b-positive cells) were counted in the caecum after immunohistochemical staining and the relative percentage of these cells in the spleen was analysed using a FACScan cytometer on days 7, 10, 14, 21, and 27 post-inoculation (pi) . In the low dose group, the number of CD3+ and CD4+ cells in the caecum had significantly increased at day 10 pi . Both CD8+ and Bu1b+ cells were significantly higher on day 14 pi in this group . In the high-dose group, the number of CD4+ cells had significantly increased at day 7 pi . CD3+, CD8+, and Bu1b+ cells showed prolonged proliferation at days 7 up to 21 pi . Splenic lymphocytes demonstrated significant changes only in the high dose group . The percentage of splenic CD4+ cells was decreased at day 7 pi . A decrease in CD3+ and CD8+ cells was found at day 14 pi in this group.

MMWR Morb Mortal Wkly Rep, 2003 Jan 3, 51(51-52), 1149 - 52
Outbreaks of Salmonella serotype enteritidis infection associated with eating shell eggs--United States, 1999-2001; Mucosal priming of simian immunodeficiency virus-specific cytotoxic T-lymphocyte responses in rhesus macaques by the Salmonella type III secretion antigen delivery system; New England Regional Primate Research Center, Harvard Medical School, One Pine Hill Drive, Southborough, MA 01772-9102, USANearly all human immunodeficiency virus (HIV) infections are acquired mucosally, and the gut-associated lymphoid tissues are important sites for early virus replication . Thus, vaccine strategies designed to prime virus-specific cytotoxic T lymphocyte (CTL) responses that home to mucosal compartments may be particularly effective at preventing or containing HIV infection . The Salmonella type III secretion system has been shown to be an effective approach for stimulating mucosal CTL responses in mice . We therefore tested DeltaphoP-phoQ attenuated strains of Salmonella enterica serovar Typhimurium and S . enterica serovar Typhi expressing fragments of the simian immunodeficiency virus (SIV) Gag protein fused to the type III-secreted SopE protein for the ability to prime virus-specific CTL responses in rhesus macaques . Mamu-A*01(+) macaques were inoculated with three oral doses of recombinant Salmonella, followed by a peripheral boost with modified vaccinia virus Ankara expressing SIV Gag (MVA Gag) . Transient low-level CTL responses to the Mamu-A*01 Gag(181-189) epitope were detected following each dose of SALMONELLA: After boosting with MVA Gag, strong Gag-specific CTL responses were consistently detected, and tetramer staining revealed the expansion of Gag(181-189)-specific CD8(+) T-cell responses in peripheral blood . A significant percentage of the Gag(181-189)-specific T-cell population in each animal also expressed the intestinal homing receptor alpha4beta7 . Additionally, Gag(181-189)-specific CD8(+) T cells were detected in lymphocytes isolated from the colon . Yet, despite these responses, Salmonella-primed/MVA-boosted animals did not exhibit improved control of virus replication following a rectal challenge with SIVmac239 . Nevertheless, this study demonstrates the potential of mucosal priming by the Salmonella type III secretion system to direct SIV-specific cellular immune responses to the gastrointestinal mucosa in a primate model.

Proteomics, 2003 Jan, 3(1), 95 - 102
Proteins induced by Xanthomonas axonopodis pv . passiflorae with leaf extract of the host plant (Passiflorae edulis); Tahara ST et al.; Two-dimensional gel electrophoresis was used to identify differentially displayed proteins during treatment of Xanthomonas axonopodis pv . passiflorae in media containing leaf extract of the compatible (passion fruit) and incompatible (tomato) hosts . The results showed that at different times of treatment (5, 25 and 45 h) the global expression of proteins was almost identical in cells grown in minimal medium (MM) and in medium containing leaf extract of the incompatible host (MMT) . The protein patterns of cells grown in medium containing passiflorae (MMP) leaf extract and MM were also compared enabling the detection of 17 differential spots . Most of the proteins were induced at earlier times of incubation (5 h) and maintained until 45 h in MMP . By using another carrier ampholyte range, seven additional proteins were identified in MMP treated cells . Five proteins, including one constitutive, two induced and two up-regulated in MMP were microsequenced . All sequences were found in the genome of xanthomonads sharing high level of identity (88-100%) . Fructose biphosphate aldolase was expressed in all media employed . A putative membrane-related protein and a hypothetical protein were novel proteins induced specifically by the passiflorae extract . An inorganic pyrophosphatase and a hypothetical protein that showed similarity to the yciF gene of Salmonella thyphimurium were up-regulated in MMP.

J Med Microbiol, 2003 Feb, 52(Pt 2), 141 - 9
Characterization of class I integrons in clinical strains of Salmonella enterica subsp . enterica serovars Typhimurium and Enteritidis from Norwegian hospitals; Lindstedt BA et al.; The characterization of integrons and their promoters in 156 antibiotic-resistant clinical isolates of the important zoonotic pathogens Salmonella enterica subsp . enterica serovars Typhimurium (S . Typhimurium) and Enteritidis (S . Enteritidis) from Norwegian hospitals were performed . Integrons were found in 64 of 66 S . Typhimurium isolates (97 %) and in 20 of 90 S . Enteritidis isolates (22.2 %) with the following sizes; 650, 1000, 1200, 1500, 1600, 1700, 2000 and 2100 bp . The integrons were further sequenced and the aadA1, aadA2, aadA5, aadB, pse-1, catB3, oxa1, dfrA1, dfrA12 and dfrA17 genes, as well as a fragment of the sat1 gene, were found embedded in cassettes . An internal fragment of the purG gene was additionally found as an artefact PCR amplicon.

Antimicrob Agents Chemother, 2003 Feb, 47(2), 697 - 703
Salmonella enterica serovar Typhimurium bla(PER-1)-carrying plasmid pSTI1 encodes an extended-spectrum aminoglycoside 6'-N-acetyltransferase of type Ib; Casin I et al.; We have studied the aminoglycoside resistance gene, which confers high levels of resistance to both amikacin and gentamicin, that is carried by plasmid pSTI1 in the PER-1 beta-lactamase-producing strain of Salmonella enterica serovar Typhimurium previously isolated in Turkey . This gene, called aac(6')-Ib(11), was found in a class 1 integron and codes for a protein of 188 amino acids, a fusion product between the N-terminal moiety (8 amino acids) of the signal peptide of the beta-lactamase OXA-1 and the acetyltransferase . The gene lacked a plausible Shine-Dalgarno (SD) sequence and was located 45 nucleotides downstream from a small open reading frame, ORF-18, with a coding capacity of 18 amino acids and a properly spaced SD sequence likely to direct the initiation of aac(6')-Ib(11) translation . AAC(6')-Ib(11) had Leu118 and Ser119 as opposed to Gln and Leu or Gln and Ser, respectively, which were observed in all previously described enzymes of this type . We have evaluated the effect of Leu or Gln at position 118 by site-directed mutagenesis of aac(6')-Ib(11) and two other acetyltransferase gene variants, aac(6')-Ib(7) and -Ib(8), which naturally encode Gln118 . Our results show that the combination of Leu118 and Ser119 confers an extended-spectrum aminoglycoside resistance, with the MICs of all aminoglycosides in clinical use, including gentamicin, being two to eight times higher for strains with Leu118 and Ser119 than for those with Gln118 and Ser119.

Clin Lab Haematol, 2003 Feb, 25(1), 63 - 5
Isolated thrombocytopenia: the presenting finding of typhoid fever; Serefhanoglu K et al.; Thrombocytopenia is generally seen as a complication in typhoid fever . However, it can also be encountered as a presenting sign on admission . A 29-year-old man with complaints of fever and diarrhoea was hospitalized because of isolated thrombocytopenia encountered on routine complete blood count examination . The diagnosis of typhoid fever was established when Salmonella typhi was isolated from the blood cultures . The platelet count returned to normal level within the first week of ceftriaxone therapy . Possible mechanisms of thrombocytopenia were discussed.

J Microbiol Immunol Infect, 2002 Dec, 35(4), 236 - 42
Monitoring the hygene of chicken hatcheries in Taiwan during 1999-2001; Chen SJ et al.; Microorganism contamination in hatcheries and eggs has a serious impact on the viability and quality of chicks as well as on the overall growth performance of chickens . Microbiological agents are present in the fluff when chicks hatch . Detecting microorganisms in fluff is a convenient method for evaluating the hygienic status in a hatchery . Fluff samples from 31 hatcheries collected over 3 years were tested for the total bacterial count, the presence of Salmonella spp., and fungus to evaluate the hygienic status of hatcheries in Taiwan from 1999 through 2001 . The total bacterial score from the fluff samples was calculated and expressed as a bacterial score in a log scale . Most hatcheries had a bacterial count ranged from scale 1 to 3 . Among the hatcheries, 13% to 29% were contaminated with Salmonella spp.; and 33% to 73% were contaminated with fungi in different quarters . The third quarter of each year was the most contaminated period (p<0.01) . According to the data obtained from the fluff tests, hatcheries keep their hygienic status and supply good quality chicks by cleaning and disinfecting.

J Microbiol Immunol Infect, 2002 Dec, 35(4), 229 - 35
Characterization of a highly attenuated Salmonella enterica serovar Typhimurium mutant strain; Tang IK et al.; Salmonella enterica serovar Typhimurium ATCC 13311 is virulent at a dose as low as 10(2) colony-forming units when administered intraperitoneally to BALB/c mice . In order to develop highly attenuated mutant strain through the combination of 2 phenotypically attenuated markers, we constructed a number of amino acid requiring auxotrophic strains of S . enterica serovar Typhimurium by means of UV-induced mutations . One of them, strain NDMC-B1, was highly attenuated for mice, with an LD50-value of 6 and 3 log units lower for mice than the wild-type strain and S . enterica serovar Typhimurium aroA strain, respectively . This strain still contained the Salmonella O- and H-antigens but had a requirement for cysteine and was unable to utilize citrate as its sole carbon source . NDMC-B1 colonized the gut-associated lymphoid tissue more efficiently than the wild-type strain, but its capacities to colonize spleen and liver were significantly reduced . Mice intraperitoneally or orally vaccinated with NDMC-B1 were highly protected against either an intraperitoneal challenge with 10(6) colony-forming units or an oral challenge with 10(9) colony-forming units of the wild-type strain . Taken together, the results illustrate that through the combination of 2 independently phenotypical attenuating markers, the requirement for cysteine and the inability to use citrate, we have successfully constructed a highly attenuated, stable, and immunogenic S . enterica serovar Typhimurium vaccine strain which can induce protective immunity in a mouse model against lethal challenge of wild-type strain.

Infect Immun, 2003 Feb, 71(2), 872 - 81
Disruption of epithelial barrier integrity by Salmonella enterica serovar typhimurium requires geranylgeranylated proteins; Tafazoli F et al.; Epithelial cells that line the human intestinal mucosa constitute the initial sites of host invasion by bacterial pathogens . A number of bacteria, such as Salmonella and Yersinia spp., have been shown to disrupt the integrity of the epithelial barrier, although little is known about the mechanisms underlying that effect . We found that polarized MDCK-1 epithelial cells infected with invasive Salmonella enterica serovar Typhimurium SL1344 exhibited marked changes in F-actin organization, an increase in the paracellular flux of dextran, and a rapid decrease in transepithelial electrical resistance (TER) . In contrast, infection with an isogenic noninvasive mutant (hilA) increased the TER in these cells . Pretreating MDCK-1 cells with the inhibitors for tyrosine kinase (genistein) or phosphatidylinositol 3-kinase (wortmannin) did not affect invasion and subsequent perturbation of the epithelial barrier by serovar Typhimurium . Instead, the geranylgeranyltransferase 1 inhibitor GGTI-298, but not the farnesyltransferase inhibitor FTI-277, clearly reversed the capacity of serovar Typhimurium to disrupt the epithelial barrier . The substrates for GGTI-298 include Rho family GTPases, as indicated by inhibiting prenylation of Rac1 and Cdc42 . Infection with wild-type serovar Typhimurium increased the level of activated Rac1 and Cdc42 and caused these proteins to accumulate apically in MDCK-1 cells . This Salmonella-induced accumulation of Rac1 and Cdc42 and alteration of the junction-associated proteins ZO-1, occludin, and E-cadherin in MDCK-1 cells were markedly inhibited by GGTI-298 . These results suggest that activation of geranylgeranylated proteins, including Rac1 and Cdc42, is critical for disruption of barrier integrity by serovar Typhimurium in polarized MDCK-1 cells.

Infect Immun, 2003 Feb, 71(2), 690 - 6
Lon, a stress-induced ATP-dependent protease, is critically important for systemic Salmonella enterica serovar typhimurium infection of mice; Takaya A et al.; Studies on the pathogenesis of Salmonella enterica serovar Typhimurium infections in mice have revealed the presence of two prominent virulence characteristics-the invasion of the nonphagocytic cells to penetrate the intestinal epithelium and the proliferation within host phagocytic cells to cause a systemic spread and the colonization of host organs . We have recently demonstrated that the ATP-dependent Lon protease of S . enterica serovar Typhimurium negatively regulates the efficiency of invasion of epithelial cells and the expression of invasion genes (A . Takaya et al., J . Bacteriol . 184:224-232, 2002) . This study was performed to reveal the contribution of the Lon protease to the virulence of S . enterica serovar Typhimurium in mice . Determination of 50% lethal doses for the lon disruption mutant and wild-type strain revealed that the mutant was highly attenuated when administered either orally or intraperitoneally to BALB/c mice . The mutant was also found to be able to reach extraintestinal sites but unable to proliferate efficiently within the spleen and cause lethal systemic disease of mice . Macrophage survival assays revealed that the lon disruption mutant could not survive or proliferate within murine macrophages . In addition, the mutant showed extremely increased susceptibility to hydrogen peroxide, which contributes to the bactericidal capacity of phagocytes . The mutant also showed increased sensitivity to acidic conditions . Taken together, the impaired ability of the lon disruption mutant to survive and grow in macrophages could be due to the enhanced susceptibility to the oxygen-dependent killing mechanism associated with respiratory burst and the low phagosomal pH . These results suggest that the Lon protease is essentially involved in the systemic infection of mice with S . enterica serovar Typhimurium, which can be fatal . Of further interest is the finding that the lon disruption mutant persists in the BALB/c mice for long periods without causing an overwhelming systemic infection.

Infect Immun, 2003 Feb, 71(2), 621 - 8
Nramp1 is not a major determinant in the control of Brucella melitensis infection in mice; Guilloteau LA et al.; Brucella, the causative agent of brucellosis in animals and humans, can survive and proliferate within macrophages . Macrophages mediate mouse resistance to various pathogens through the expression of the Nramp1 gene . The role of this gene in the control of Brucella infection was investigated . When BALB/c mice (Nramp1(s)) and C.CB congenic mice (Nramp1(r)) were infected with Brucella melitensis, the number of Brucella organisms per spleen was significantly larger in the C.CB mice than in the BALB/c mice during the first week postinfection (p.i.) . This Nramp1-linked susceptibility to Brucella was temporary, since similar numbers of Brucella were recovered from the two strains of mice 2 weeks p.i . The effect of Nramp1 expression occurred within splenocytes intracellularly infected by BRUCELLA: However, there was no difference between in vitro replication rates of Brucella in macrophages isolated from the two strains of mice infected in vivo or in Nramp1 RAW264 transfectants . In mice, infection with Brucella induced an inflammatory response, resulting in splenomegaly and recruitment of phagocytes in the spleen, which was amplified in C.CB mice . Reverse transcription-PCR (RT-PCR), performed 5 days p.i., showed that inducible nitric oxide synthase, tumor necrosis factor alpha (TNF-alpha), interleukin-12 p40 (IL-12p40), gamma interferon (IFN-gamma), and IL-10 mRNAs were similarly induced in spleens of the two strains . In contrast, the mRNA of KC, a C-X-C chemokine, was induced only in infected C.CB mice at this time . This pattern of mRNA expression was maintained at 14 days p.i., with IFN-gamma and IL-12p40 mRNAs being more intensively induced in the infected C.CB mice, but TNF-alpha mRNA was no longer induced . The higher recruitment of neutrophils observed in the spleens of infected C.CB mice could explain the temporary susceptibility of C.CB mice to B . melitensis infection . In contrast to infections with Salmonella, Leishmania, and Mycobacterium, the expression of the Nramp1 gene appears to be of limited importance for the natural resistance of mice to Brucella.

Expert Opin Ther Targets, 2001 Jun, 5(3), 327 - 339
The Type III secretion system of Gram-negative bacteria: a potential therapeutic target?
Muller S, Feldman MF, Cornelis GR.
Several pathogenic Gram-negative bacteria, including Salmonella, Shigella, Yersinia, Pseudomonas aeruginosa and enteropathogenic Escherichia coli harbour a complex attack system called 'Type III secretion' which is, in every case, an essential virulence determinant . This system, activated by contact with an eukaryotic cell membrane, allows bacteria to inject bacterial proteins across the two bacterial membranes and the eukaryotic cell membrane, to reach the cell's cytosol and destroy or subvert the host cell . The Type III virulence mechanism consists of a secretion apparatus, made up of about 25 proteins, and a set of effector proteins released by this apparatus . The mechanism of protein secretion is highly conserved among the different bacteria, although they cause a variety of diseases with different symptoms and severities, from fatal septicaemia to mild diarrhoea or from fulgurant diarrhoea to chronic infection of the lung . This review focuses on the proteins that make up the secretion machinery and examine if it could be a potential target for novel antimicrobials.

J Food Prot, 2003 Jan, 66(1), 31 - 7
Comparison of sublethal injury induced in Salmonella enterica serovar Typhimurium by heat and by different nonthermal treatments; Wuytack EY et al.; We have studied sublethal injury in Salmonella enterica serovar Typhimurium caused by mild heat and by different emerging nonthermal food preservation treatments, i.e., high-pressure homogenization, high hydrostatic pressure, pulsed white light, and pulsed electric field . Sublethal injury was determined by plating on different selective media, i.e., tryptic soy agar (TSA) plus 3% NaCl, TSA adjusted to pH 5.5, and violet red bile glucose agar . For each inactivation technique, at least five treatments using different doses were applied in order to cover an inactivation range of 0 to 5 log units . For all of the treatments performed with a technique, the logarithm of the viability reductions measured on each of the selective plating media was plotted against the logarithm of the viability reduction on TSA as a nonselective medium, and these points were fined by a straight line . Sublethal injury between different techniques was then compared by the slope and the y intercept of these regression lines . The highest levels of sublethal injury were observed for the heat and high hydrostatic pressure treatments . Sublethal injury after those treatments was observed on all selective plating media . For the heat treatment, but not for the high-pressure treatment, sublethal injury occurred at low doses, which were not yet lethal . The other nonthermal techniques resulted in sublethal injury on only some of the selective plating media, and the levels of injury were much lower . The different manifestations of sublethal injury were attributed to different inactivation mechanisms by each of the techniques, and a mechanistic model is proposed to explain these differences.

J Food Prot, 2003 Jan, 66(1), 13 - 7
Alfalfa sprouts and Salmonella Kottbus infection: a multistate outbreak following inadequate seed disinfection with heat and chlorine; Winthrop KL et al.; Raw sprouts have been implicated in a number of foodborne disease outbreaks . Because contaminated seeds are usually responsible, many sprout producers attempt to disinfect seeds before germination and detect sprout contamination during production . In March 2001, we detected an increased number of Salmonella serotype Kottbus isolates in California . Overall, we identified 31 cases from three western states . To identify the cause, we conducted a case-control study with the first 10 identified case-patients matched to 20 controls by age, sex, and residential area . Our case-control study found illness to be statistically associated with alfalfa sprout consumption . The traceback investigation implicated a single sprouter, where environmental studies yielded Salmonella Kottbus from ungerminated seeds and floor drains within the production facility . Pulsed-field gel electrophoresis patterns of all patient, seed, and floor drain Salmonella Kottbus isolates were indistinguishable . Most implicated sprouts were from seeds that underwent heat treatment and soaking with a 2,000-ppm sodium hypochlorite solution rather than the Food and Drug Administration (FDA)-recommended 20,000-ppm calcium hypochlorite soak . Other implicated seeds had been soaked in a calcium hypochlorite solution that, when tested, measured only 11,000 ppm . The outbreak might have been averted when screening tests of sprout irrigation water detected Salmonella in January; however, confirmatory testing of these samples was negative (but testing improperly utilized refrigerated irrigation water) . Producers should use the enrichment broth of positive screening samples, not refrigerated irrigation water, for confirmatory testing . Until other effective disinfection technologies are developed, producers should adhere to FDA recommendations for sprout seed disinfection.

J Endotoxin Res, 2002, 8(5), 343 - 356
Structural and biological characterization of highly purified hepta-acyl lipid A present in the lipopolysaccharide of the Salmonella enterica sv . Minnesota Re deep rough mutant strain R595; Janusch H et al.; One major component of the Salmonella enterica sv . Minnesota Re deep rough mutant (strain R595) lipopolysaccharide is hepta-acyl lipid A (LA(hepta)) . In a recent publication {Tanamoto K-I, Azumi S . Salmonella-type heptaacylated lipid A is inactive and acts as an antagonist of lipopolysaccharide action on human line cells . J Immunol 2000; 164: 3149-3156} the corresponding synthetic hepta-acyl lipid A (compound 516) was reported to be agonistically inactive but to rather suppress pro-inflammatory activation by the endotoxic hexa-acyl lipid A (LA(hexa), compound 506) and S-form LPS from Escherichia coli in the human macrophage-like cell lines THP-1 and U937 . These results, however, were in contrast to previous findings with human mononuclear cells (hMNC) isolated from peripheral blood, in which compound 516 was found to be an agonist, expressing low, but significant, cytokine-inducing activity as compared to LA(hexa) . We have investigated the structure of natural LA(hepta) from the S . enterica sv . Minnesota Re deep rough mutant strain (R595) by TLC immunoblot, MALDI-TOF mass spectrometry and NMR spectroscopy . Using these techniques, the structural identity between LA(hepta) and the synthetic compound 516 was confirmed . In corroboration of previous findings with studies employing compound 516, purified LA(hepta) was found to induce the production of TNF-alpha, IL-1beta and IL-6 in hMNC, thus displaying moderate agonistic activity . Furthermore, we showed that LA(hepta) agonistically activated nuclear translocation of NF-kappaB in THP-1 cells, thus clearly ruling out the possibility that LA(hepta) is an antagonist and that its biological activity is influenced by the type of human myeloid cells used for testing endotoxicity (hMNC versus THP-1 cells).

J Am Coll Cardiol, 2003 Jan 15, 41(2), 333 - 9
Acute systemic inflammation enhances endothelium-dependent tissue plasminogen activator release in men; Chia S et al.; OBJECTIVES: The purpose of this study was to investigate in vivo the effects of acute systemic inflammation on the endogenous fibrinolytic capacity in men . BACKGROUND: Systemic inflammation and endogenous fibrinolysis play a major role in the pathogenesis of coronary artery disease . Although previous studies have shown impaired endothelium-dependent vasomotor function, the effects of inflammation on the endothelial release of the fibrinolytic factor tissue plasminogen activator (t-PA) are unknown . METHODS: In a double-blind randomized placebo-controlled crossover trial, we administered a mild inflammatory stimulus, Salmonella typhi vaccine, or saline placebo to eight healthy men on two separate occasions . Six hours after vaccination, blood flow and plasma fibrinolytic variables were measured in both arms during intrabrachial infusions of bradykinin (40 to 1,000 pmol/min), acetylcholine (5 to 20 microg/min), and sodium nitroprusside (2 to 8 microg/min) . RESULTS: Compared with placebo, the S . typhi vaccination caused a rise in white cell count (11.1 +/- 0.5 x10(9)/l vs . 7.9 +/- 0.8 x10(9)/l; p = 0.004) and plasma interleukin-6 concentrations (6.9 +/- 1.4 pg/ml vs . 1.6 +/- 0.4 pg/ml; p = 0.01) in addition to a significant augmentation of t-PA antigen (45 +/- 9 ng/100 ml/min at peak dose vs . 24 +/- 8 ng/100 ml/min at peak dose; p = 0.016, analysis of variance) and activity (104 +/- 15 IU/100 ml/min vs . 54 +/- 12 IU/100 ml/min; p = 0.006, analysis of variance) release during bradykinin infusion . Forearm blood flow increased in a dose-dependent manner after bradykinin, acetylcholine and sodium nitroprusside infusions (p < 0.001), but this was unaffected by vaccination . CONCLUSIONS: Our results showed that acute systemic inflammation augmented local forearm t-PA release in men, which suggests that acute inflammation may invoke a protective response by enhancing the acute endogenous fibrinolytic capacity in healthy men . Further studies are needed to clarify whether this response is impaired in patients with cardiovascular disease.

Mol Microbiol, 2003 Feb, 47(3), 793 - 805
A new Escherichia coli metabolic competency: growth on fatty acids by a novel anaerobic beta-oxidation pathway; Campbell JW et al.; Escherichia coli uses fatty acids as a sole carbon and energy source during aerobic growth by means of the enzymes encoded by the fad regulon . We report that this bacterium can also grow on fatty acids under anaerobic conditions provided that a terminal respiratory electron acceptor such as nitrate is available . This anaerobic utilization pathway is distinct from the well-studied aerobic pathway in that (i) . it proceeds normally in mutant strains lacking various enzymes of the aerobic pathway; (ii) . it functions with fatty acids (octanoate and decanoate) that cannot be used by wild-type E . coli strains under aerobic conditions; and (iii) . super-repressor mutants of the fadR regulatory locus that block aerobic growth on fatty acids fail to block the anaerobic pathway . We have identified homologues of the FadA, FadB and FadD proteins required for aerobic fatty acid utilization called YfcY, YfcX and YdiD, respectively, which are involved in anaerobic growth on fatty acids . A strong FadR binding site was detected upstream of the yfcY gene consistent with microarray analyses, indicating that yfcYX expression is negatively regulated by FadR under aerobic growth conditions . In contrast, transcriptional regulation of ydiD appears to be independent of FadR, and anaerobic growth on fatty acids is not under FadR control . These three genes are conserved in the available genome sequences of pathogenic E . coli, Shigella and Salmonella strains.

J Appl Microbiol, 2003, 94(2), 340 - 8
The pathogenicity of strains of Salmonella paratyphi B and Salmonella java; Chart H; AIMS: To relate the diseases caused by strains of Salmonella paratyphi B and S . java to pathogenic mechanisms expressed by these bacteria for the purpose of organism discrimination . METHODS AND RESULTS: Epidemiological data relating to cases of disease caused by strains of S . paratyphi B and S . java, isolated over a 10-year period, were analysed with respect to patients' symptoms, particularly those involving enteric fever . Strains of S . paratyphi B and S . java were also examined for a range of known pathogenic mechanisms . Infection with S . paratyphi B involved pyrexia in 12.5% of patients compared with 2.2% of patients infected with S . java . These organisms could not be differentiated based on the pathogenic properties examined . CONCLUSIONS: Strains of S . paratyphi B appear not to be a major cause of enteric fever but primarily a cause of gastroenteritis, in common with S . java . Both organisms express similar pathogenic mechanisms, and strains of S . java are probably d-tartrate utilizing variants of S . paratyphi B . SIGNIFICANCE AND IMPACT OF THE STUDY: Strains of S . paratyphi B are very closely related organisms, primarily causing gastroenteritis . From this study it would appear that strains of S . paratyphi B are not a major cause of enteric fever.

J Appl Microbiol, 2003, 94(2), 207 - 13
Effects of the antibiotic ionophores monensin, lasalocid, laidlomycin propionate and bambermycin on Salmonella and E . coli O157:H7 in vitro; Edrington TS et al.; AIMS: To examine the effects of ionophores on Salmonella and Escherichia coli O157:H7 in pure and mixed ruminal fluid cultures . METHODS AND RESULTS: Four Salmonella serotypes (Dublin, Derby, Typhimurium, and Enteriditis) and two strains of E . coli O157:H7 (ATCC 43895 and FDIU 6058) were cultured in the presence of varying concentrations of ionophores (monensin, lasalocid, laidlomycin propionate, and bambermycin) in pure and mixed ruminal fluid cultures . Bacterial growth rates in pure culture were not affected (P > 0.10) by ionophores at concentrations up to 10 times the approximate rumen ionophore concentration under normal feeding regimens . Likewise, ionophores had no effect (P > 0.10) on Salmonella or E . coli CFU plated from 24-h ruminal fluid incubations . Ionophore treatment decreased (P < 0.01) the acetate : propionate ratio in ruminal fluid cultures as expected . CONCLUSIONS: Ionophores had no effect on the foodborne pathogens Salmonella and E . coli O157:H7 in vitro . SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that ionophore feeding would have little or no effect on Salmonella or E . coli populations in the ruminant.

J Appl Microbiol, 2003, 94(2), 191 - 6
Investigation of Salmonella contamination and disinfection in farm egg-packing plants; Davies RH et al.; AIMS: As part of a field-based study of the distribution and persistence of Salmonella infection on commercial egg-laying farms, sampling was carried out on one or more occasions in egg-packing areas of 12 farms infected with Salm . Enteritidis . METHODS AND RESULTS: Salmonellas were isolated by cultural methods . Contamination was common, with Salmonella being found in 23.1% of floor swab samples, 30.8% of grading tables, 23.1% of conveyor belts or rollers and 23.8% of candlers . Four farms were sampled after cleaning and disinfection of packing plants had been carried out on the previous day, and residual contamination was found on 6.9% of samples from grading tables, 16.0% holding/sorting tables, 12.6% of conveyors or rollers, 16.7% of vacuum egg lifters, 21.4% of floor surfaces and 5.0% of egg store floor surfaces . Sterilized eggs passed through five farm packing plants showed a contamination rate of at least 16/5,948 (0.3%) egg passages . CONCLUSIONS: It is apparent that contamination in egg-packing plants may be a significant contributory factor to external contamination of shell eggs, and improved methods of cleaning and disinfecting egg-handling equipment are required . SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of Salmonella contamination in egg-packing plants presents a contamination hazard for eggs from Salmonella-free flocks . Samples from equipment in the packing plant could also be used for screening for detection of Salmonella in the throughout of the plant.

J Bacteriol, 2003 Feb, 185(3), 1107 - 11
The high-pathogenicity island is absent in human pathogens of Salmonella enterica subspecies I but present in isolates of subspecies III and VI; Oelschlaeger TA et al.; In this study we tested 74 Salmonella strains of all eight Salmonella groups and were able to demonstrate the presence of two high-pathogenicity island types in strains of Salmonella groups IIIa, IIIb, and VI . Most high-pathogenicity island-positive isolates produced yersiniabactin under iron-limited conditions and were positive for the high-molecular-weight proteins HMWP1 and HMWP2.

J Bacteriol, 2003 Feb, 185(3), 750 - 9
1-methylguanosine-deficient tRNA of Salmonella enterica serovar Typhimurium affects thiamine metabolism; Bjork GR et al.; In Salmonella enterica serovar Typhimurium a mutation in the purF gene encoding the first enzyme in the purine pathway blocks, besides the synthesis of purine, the synthesis of thiamine when glucose is used as the carbon source . On carbon sources other than glucose, a purF mutant does not require thiamine, since the alternative pyrimidine biosynthetic (APB) pathway is activated . This pathway feeds into the purine pathway just after the PurF biosynthetic step and upstream of the intermediate 4-aminoimidazolribotide, which is the common intermediate in purine and thiamine synthesis . The activity of this pathway is also influenced by externally added pantothenate . tRNAs from S . enterica specific for leucine, proline, and arginine contain 1-methylguanosine (m(1)G37) adjacent to and 3' of the anticodon (position 37) . The formation of m(1)G37 is catalyzed by the enzyme tRNA(m(1)G37)methyltransferase, which is encoded by the trmD gene . Mutations in this gene, which result in an m(1)G37 deficiency in the tRNA, in a purF mutant mediate PurF-independent thiamine synthesis . This phenotype is specifically dependent on the m(1)G37 deficiency, since several other mutations which also affect translation fidelity and induce slow growth did not cause PurF-independent thiamine synthesis . Some antibiotics that are known to reduce the efficiency of translation also induce PurF-independent thiamine synthesis . We suggest that a slow decoding event at a codon(s) read by a tRNA(s) normally containing m(1)G37 is responsible for the PurF-independent thiamine synthesis and that this event causes a changed flux in the APB pathway.

Emerg Infect Dis, 2003 Jan, 9(1), 120 - 2
Household contamination with Salmonella enterica; Rice DH et al.; Household contamination with Salmonella enterica increases when occupational exposure exists (cattle farms with known salmonellosis in cattle, a salmonella research laboratory, or a veterinary clinic experiencing an outbreak of salmonellosis) . Fifteen of 55 (27.2%) vacuum cleaner bags from households with occupational exposure to S . enterica were positive versus 1 of 24 (4.2%) without known exposure . Use of a carpet cleaner and several cleaners/disinfectants reduced, but failed to eliminate, S . enterica from artificially contaminated carpet.

Braz J Med Biol Res, 2003 Jan, 36(1), 3 - 12
Pathogenesis of Salmonella-induced enteritis; Santos RL et al.; Infections with Salmonella serotypes are a major cause of food-borne diseases worldwide . Animal models other than the mouse have been employed for the study of nontyphoidal Salmonella infections because the murine model is not suitable for the study of Salmonella-induced diarrhea . The microbe has developed mechanisms to exploit the host cell machinery to its own purpose . Bacterial proteins delivered directly into the host cell cytosol cause cytoskeletal changes and interfere with host cell signaling pathways, which ultimately enhance disease manifestation . Recently, marked advances have been made in our understanding of the molecular interactions between Salmonella serotypes and their hosts . Here, we discuss the molecular basis of the pathogenesis of Salmonella-induced enteritis.

Rev Inst Med Trop Sao Paulo, 2002 Nov-Dec, 44(6), 315 - 9
Conventional and molecular typing of Salmonella typhi strains from Brazil; Quintaes BR et al.; Phenotypic and genotypic characteristics of Salmonella Typhi were studied in 30 strains, isolated in different years, from some areas in Brazil . Conventional typing methods were performed by biochemical tests, Vi phage-typing scheme, and antimicrobial susceptibility test . Molecular typing methods were performed by analysis of plasmid DNA and by random amplified polymorphic DNA (RAPD-PCR) . For the latter, an optimization step was performed to ensure the reproducibility of the process in genetic characterization of S . Typhi . The predominance of 76.7% of biotype I (xylose +, arabinose -) was noticed in all studied areas . Three phage types were recognized, with prominence for the phage types A (73.3%) and I+IV (23.3%) . All the strains were susceptible to the drugs used . However, 36.7% of the strains contained plasmids, with predominance of the 105 Kb plasmid . RAPD was capable of grouping the strains in 8 genotypic patterns using primer 784, in 6, using primer 787 and in 7, using primer 797 . Conventional phenotypic typing methods, as well as the DNA plasmid analysis, presented nonsignificant discriminatory power; however, RAPD-PCR analysis showed discriminatory power, reproducibility, easy interpretation and performance, being considered as a promising alternative typing method for S . Typhi.

Vaccine, 2003 Jan 17, 21(5-6), 566 - 78
Therapeutic efficacy of an E coli strain carrying an ovalbumin allergenic peptide as a fused protein to OMPC in a murine model of allergic airway inflammation; Yepez SH et al.; An Escherichia coli strain expressing the ovalbumin (OVA) 323-329 allergenic peptide on the bacterial surface was evaluated for its ability to reduce the lung inflammatory response in mice allergic to OVA . BALB/c mice were rendered allergic by means of two intraperitoneal injections of OVA suspended in alum 5 days apart, and one intratracheal boost 1 week later . The mice were then treated with two intranasal, 1 week apart, doses of 4x10(9) E . coli-UH302 transformed with plasmids pST13 or pST13-OVA(323-339), which bear the OmpC porin from Salmonella enterica serovar Typhi or the OmpC with the OVA allergenic 323-339 amino acid sequence inserted in the external loop 5 . The allergic inflammatory reaction was evaluated on day 31, finding that mice treated with E . coli-UH302-pST13-OVA reduced four to seven times perivascular and peribronchial infiltrates, mucus production, goblet cell hyperplasia and eosinophils when compared with mice treated with E . coli-UH302-pST13 or saline solution . These results were consistent with a significant decrease of IL-5 mRNA and induction of IFN-gamma mRNA in cells from bronchio-alveolar lavages (BAL) . Specific serum IgE anti-OVA was also reduced, although the decrease did not reach statistical significance . These results demonstrate that the bacterial live vector bearing an allergenic peptide successfully moderated two important components of allergy, pulmonary inflammation and mucus overproduction.

Vaccine, 2003 Jan 17, 21(5-6), 538 - 48
Salmonella typhi and S typhimurium derivatives harbouring deletions in aromatic biosynthesis and Salmonella Pathogenicity Island-2 (SPI-2) genes as vaccines and vectors; Khan SA et al.; The S . typhimurium strain (TML deltaaroC deltassaV) WT05, harbouring defined deletions in genes involved in both the aromatic biosynthesis pathway (aroC) and the Salmonella Pathogenicity Island-2 (SPI-2) (ssaV) was shown to be significantly attenuated in C57 BL/6 interferon gamma knockout mice following oral inoculation . Similarly, the S . typhi strain (Ty2 deltaaroC deltassaV) ZH9 harbouring the aroC and ssaV mutations propagated less efficiently than wild type in human macrophages . These studies demonstrated the attractive safety profile of the aroC ssaV mutant combination . Strains S . typhimurium (TML deltaaroC deltassaV ) WT05 and S . typhi (Ty2 deltaaroC deltassaV) ZH9 were subsequently tested as vaccine vectors to deliver E . coli heat-labile toxin (LT-B) mucosally to mice . Mice inoculated orally with S . typhimurium (TML deltaaroC deltassaV) WT05 expressing LT-B (WT05/LT-B) elicited high titres of both LT-specific serum IgG and intestinal IgA, although no specific IgA was detected in the vagina . Similarly, intranasal inoculation of mice with S . typhi (Ty2 deltaaroC deltassaV) ZH9 expressing LT-B (ZH9/LT-B) elicited even higher titres of LT-specific serum antibody as well as LT-specific Ig in the vagina . We conclude that deltaaroC deltassaV strains of Salmonella are highly attenuated and are promising candidates both as human typhoid vaccines and as vaccine vectors for the delivery of heterologous antigens.

Vaccine, 2003 Jan 17, 21(5-6), 401 - 18
Animal models paving the way for clinical trials of attenuated Salmonella enterica serovar Typhi live oral vaccines and live vectors; Pasetti MF et al.; Attenuated Salmonella enterica serovar Typhi (S . Typhi) strains can serve as safe and effective oral vaccines to prevent typhoid fever and as live vectors to deliver foreign antigens to the immune system, either by the bacteria expressing antigens through prokaryotic expression plasmids or by delivering foreign genes carried on eukaryotic expression systems (DNA vaccines) . The practical utility of such live vector vaccines relies on achieving a proper balance between minimizing the vaccine's reactogenicity and maximizing its immunogenicity . To advance to clinical trials, vaccine candidates need to be pre-clinically evaluated in relevant animal models that attempt to predict what their safety and immunogenicity profile will be when administered to humans . Since S . Typhi is a human-restricted pathogen, a major obstacle that has impeded the progress of vaccine development has been the shortcomings of the animal models available to assess vaccine candidates . In this review, we summarize the usefulness of animal models in the assessment of the degree of attenuation and immunogenicity of novel attenuated S . Typhi strains as vaccine candidates for the prevention of typhoid fever and as live vectors in humans.

Vaccine, 2003 Jan 17, 21(5-6), 368 - 75
Immunogenicity and protective efficacy of a formalin-inactivated rotavirus vaccine combined with lipid adjuvants; Johansen K et al.; The immunogenicity and protective efficacy of inactivated rotavirus vaccine administered intramuscularly with lipid adjuvants; MPL (monophosphoryl lipid A from Salmonella minnesota) or L3 (monooleate/lauric acid) was evaluated in an infant mouse model . Purified and formalin-inactivated rhesus rotavirus (I-RRV) combined with one of the adjuvants were administered to female balb/c mice at 0, 4 and 8 weeks . High serum IgG antibody titers developed in all vaccinated groups; I-RRV (GMT 45524+/-9819), I-RRV-MPL (GMT 190637+/-64250) and I-RRV-L3 (GMT 126266+/-27553) . The formalin-inactivation procedure preserved neutralizing epitopes and elicited high neutralizing antibody titers; I-RRV (GMT 43053 S.E.M.+/-4189), I-RRV-MPL (GMT 66398 S.E.M.+/-20202) and I-RRV-L3 (GMT 60887 S.E.M.+/-10750) . All offsprings to immunized dams were protected against clinical diarrhea upon oral challenge with RRV . The IgG1/IgG2a ratio was in all immunized groups approximately 1 suggesting development of a balanced Th1/Th2 response.

Vaccine, 2003 Jan 30, 21(7-8), 798 - 801
Towards new immunotherapies: targeting recombinant cytokines to the immune system using live attenuated Salmonella; Rosenkranz CD et al.; We have used Salmonella as a delivery system for eukaryotic expression plasmids encoding cytokines, and assessed its capacity to modulate immune responses in different experimental models . Plasmids encoding mouse IL-4 and IL-18 under cytomegalovirus promoter were constructed and transformed into live attenuated Salmonella enterica serovar Typhi strain CVD 908-htrA, and Salmonella enterica serovar Typhimurium strain SL3261 . We have shown that systemic as well as mucosal immunization with such constructs can influence the antibody and cytokine responses to the Salmonella carrier and to co-administered bystander antigens, as well as the specific immune response elicited during a parasitic infection . Further, we have shown that oral cytokine-therapy using Salmonella as gene vector induce antitumoral effect as demonstrated by extended survival time in melanoma-bearing mice.This approach may be particularly suited for the development of new immunotherapies with applications in parasitic infections and cancer, were alterations of the host's immune responses are usually found, and therapy-induced modulation of the immune response is likely to be required.

Vaccine, 2003 Jan 30, 21(7-8), 746 - 52
Protection against murine listeriosis by oral vaccination with recombinant Salmonella expressing protective listerial epitopes within a surface-exposed loop of the TolC-protein; Spreng S et al.; Based on the topology of the outer membrane protein TolC of Escherichia coli, a new plasmid-encoded system was created which allows the expression of antigenic peptides within permissive, surface-exposed domains of TolC . To assess the capacity of this novel antigen display system, a protective CD4 T-cell epitope of the p60 protein of Listeria monocytogenes was inserted within an extracellular loop of the TolC-protein and expressed in surface-exposed form by attenuated Salmonella enteritidis . Mice immunized orally with this recombinant S . enteritidis live vaccine strain were protected against a lethal challenge with wildtype L . monocytogenes.

Vaccine, 2003 Jan 30, 21(7-8), 678 - 83
Experience with registered mucosal vaccines; Dietrich G et al.; Most pathogens gain access to their host through mucosal surfaces . It is therefore desirable to develop vaccination strategies that lead to mucosal immune responses . Ideally, a vaccine should be administered mucosally in order to elicit mucosal protection . Several attenuated live viral and bacterial pathogens are registered as oral vaccines for human use, including the oral polio vaccine (Sabin) as well as attenuated strains of Salmonella typhi and Vibrio cholerae . These attenuated bacterial live vaccines-S . typhi Ty21a as well as V . cholerae CVD 103-HgR-are employed as vaccines against typhoid and cholera, respectively . In this manuscript, we review the immune responses that are induced by these vaccines, with a focus on mucosal immunity.

Ann Trop Paediatr, 2002 Dec, 22(4), 380 - 2
Isolated splenic infarction owing to group B Salmonella: case report; Kupeli S et al.; The clinical spectrum of extra-intestinal salmonellosis, comprising enteric fever and invasive infections owing to non-typhoidal Salmonellae, is well known . We report an otherwise healthy patient with isolated splenic infarction caused by group B Salmonella . She was seropositive for the O antigen of Salmonella group B and stool cultures were positive for group B Salmonellae . After appropriate antimicrobial therapy, her complaints disappeared and microbiological tests for Salmonellae became negative.

Keio J Med, 2002 Dec, 51 Suppl 2, 6 - 14
Helicobacter pylori type IV secretion, host cell signalling and vaccine development; Backert S et al.; Helicobacter pylori is a bacterial pathogen specialised to colonise and persist the gastric mucosa and to cause severe gastroduodenal disease . A major disease-associated bacterial component is a type IV secretion system (TFSS) encoded by the cytotoxin-associated genes pathogenicity island (cagPAI) . Among the multiple responses in H . pylori-infected epithelial cells, the induction of proinflammatory cytokines and chemokines, cell spreading and motility associated with the "hum mingbird" phenotype appear strictly dependent on the functional transporter complex in the cagPAI . H . pylori is also capable of occasionally entering epithelial cells and manipulates the host immune system for immune evasion . Attached bacteria actively translocate the CagA protein into epithelial cells by a TFSS-dependent process and translocated CagA undergoes tyrosine phosphorylation in the carboxy terminal EPIYA sequence repeat motif (Y-972) by kinases of the Src family . Furthermore, we have identified a novel TFSS in H . pylori involved in horizontal DNA-transfer . Host cell signalling events and cellular phenotypes provoked by the cagPAI, the investigation of mechanisms related to gastric cancer as well as the development of a Salmonella based live recombinant vaccine are in the focus of additional departmental activities.

Can J Vet Res, 2003 Jan, 67(1), 39 - 47
Characterization of integron mediated antimicrobial resistance in Salmonella isolated from diseased swine; White DG et al.; Forty-two Salmonella isolates obtained from diseased swine were genetically characterized for the presence of specific antimicrobial resistance mechanisms . Twenty of these isolates were characterized as S . Typhimurium DT104 strains . Pulsed-field gel electrophoresis was used to determine genetic relatedness and revealed 20 distinct genetic patterns among the 42 isolates . However, all DT104 isolates fell within 2 closely related genetic clusters . Other Salmonella isolates were genetically grouped together according to serotype . All DT104 isolates displayed the penta-resistance phenotype to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline . Resistance to sulfamethoxazole, tetracycline, streptomycin, kanamycin, and ampicillin was most common among the non-DT104 Salmonella isolates . All DT104 strains contained 2 chromosomal integrons of 1000 and 1200 base pairs . The DNA sequencing revealed that the 2 integrons contained genes encoding a resistance to streptomycin and ampicillin, respectively . None of the non-DT104 strains showed the same pattern, although several strains possessed integrons of 1000 base pairs or larger . However, the majority of non-DT104 Salmonella strains did not possess any integrons . Two Salmonella isolates displayed tolerance to the organic solvent cyclohexane, indicating the possibility that they are overexpressing chromosomal regulatory genes marA or soxS or the associated multidrug efflux pump, acrAB . This research suggests that integrons contribute to antimicrobial resistance among specific swine Salmonella serotypes; however, they are not as widely disseminated among non-Typhimurium swine Salmonella serotypes as previously thought.

J Wildl Dis, 2002 Oct, 38(4), 685 - 92
Morbidity and mortality factors in key deer (Odocoileus virginianus clavium); Nettles VF et al.; The population health of endangered Key deer (Odocoileus virginianus clavium) was monitored from 10 February 1986 to 28 September 2000 by necropsy of animals that were killed by vehicles, euthanized because of terminal injuries or disease conditions, or found dead . The predominant mortality factor during the period was collision with motor vehicles; however, several infectious diseases were diagnosed, including infections with Arcanobacterium pyogenes, Haemonchus contortus, Salmonella spp., and Mycobacterium avium subsp . paratuberculosis . During the period monitored, the only infectious disease that was thought to have affected population dynamics was haemonchosis . Nevertheless, several of the observed diseases have potential to impact viability of the Key deer population under appropriate environmental conditions.

Immunol Lett, 2003 Jan 22, 85(2), 99 - 102
The role of dendritic cells in the immune response to Salmonella; Wick MJ; Dendritic cells (DC) are an important link between the innate and adaptive immune response and are key antigen presenting cells in triggering specific immunity . This review summarizes the role of DC and the DC subsets during infection with the facultative intracellular bacterium Salmonella . The capacity of DC to stimulate Salmonella-specific T cells by direct and indirect presentation of Salmonella antigens as well as the cytokine production capacity of DC upon Salmonella encounter are discussed . In addition, changes in the number, localization and cytokine production by splenic DC subsets during infection are reviewed . Studying the function of DC during Salmonella infection provides insight into the capacity of this phagocytic antigen presenting cell to initiate and modulate an immune response during bacterial infection.

Trends Microbiol, 2003 Jan, 11(1), 2 - 6
Genomic variability among enteric pathogens: the case of the mutS-rpoS intergenic region; Kotewicz ML et al.; The mutS-rpoS intergenic region of enteric bacteria ranges in size from 88 bp in Yersinia to > 12000 bp in Salmonella . We interpret this expansion as the result of the horizontal transfer of segments of DNA from diverse origins . Both comparative genomic analysis and selective sequencing of a variety of Escherichia coli pathogens have provided additional evidence for reassortment of segments within this region.

Curr Biol, 2003 Jan 8, 13(1), 47 - 52
Caenorhabditis elegans innate immune response triggered by Salmonella enterica requires intact LPS and is mediated by a MAPK signaling pathway; Aballay A et al.; Compared to mammals, insects, and plants, relatively little is known about innate immune responses in the nematode Caenorhabditis elegans . Previous work showed that Salmonella enterica serovars cause a persistent infection in the C . elegans intestine that triggers gonadal programmed cell death (PCD) and that C . elegans cell death (ced) mutants are more susceptible to Salmonella-mediated killing . To further dissect the role of PCD in C . elegans innate immunity, we identified both C . elegans and S . enterica factors that affect the elicitation of Salmonella-induced PCD . Salmonella-elicited PCD was shown to require the C . elegans homolog of the mammalian p38 mitogen-activated protein kinase (MAPK) encoded by the pmk-1 gene . Inactivation of pmk-1 by RNAi blocked Salmonella-elicited PCD, and epistasis analysis showed that CED-9 lies downstream of PMK-1 . Wild-type Salmonella lipopolysaccharide (LPS) was also shown to be required for the elicitation of PCD, as well as for persistence of Salmonella in the C . elegans intestine . However, a presumptive C . elegans TOLL signaling pathway did not appear to be required for the PCD response to Salmonella . These results establish a PMK-1-dependant PCD pathway as a C . elegans innate immune response to Salmonella.

Genetics, 2002 Dec, 162(4), 1513 - 23
Regulation of capsule synthesis and cell motility in Salmonella enterica by the essential gene igaA; Cano DA et al.; Mutants of Salmonella enterica carrying the igaA1 allele, selected as able to overgrow within fibroblast cells in culture, are mucoid and show reduced motility . Mucoidy is caused by derepression of wca genes (necessary for capsule synthesis); these genes are regulated by the RcsC/YojN/RcsB phosphorelay system and by the RcsA coregulator . The induction of wca expression in an igaA1 mutant is suppressed by mutations in rcsA and rcsC . Reduced motility is caused by lowered expression of the flagellar master operon, flhDC, and is suppressed by mutations in rcsB or rcsC, suggesting that mutations in the igaA gene reduce motility by activating the RcsB/C system . A null igaA allele can be maintained only in an igaA(+)/igaA merodiploid, indicating that igaA is an essential gene . Lethality is suppressed by mutations in rcsB, rcsC, and yojN, but not in rcsA, suggesting that the viability defect of an igaA null mutant is mediated by the RcsB/RcsC system, independently of RcsA (and therefore of the wca genes) . Because all the defects associated with igaA mutations are suppressed by mutations that block the RcsB/RcsC system, we propose a functional interaction between the igaA gene product and either the Rcs regulatory network or one of its regulated products.

Water Sci Technol, 2002, 46(11-12), 325 - 30
Risk evaluation for pathogenic bacteria and viruses in sewage sludge compost; Watanabe T et al.; Composting can be regarded as the most available option for recycling of sewage sludge . However, the existence of pathogenic bacteria and viruses in the compost has been scarcely investigated until now . So there is little information on the infectious risk through agricultural activities or gardening in using the compost . In this study, several kinds of composts were investigated for detection of pathogenic bacteria (Salmonella spp . and Escherichia coli O157) and enteric viruses . It was concluded from the result that these bacteria and viruses could not be detected in 1.0 g-wet of any kinds of composts . Infectious risks through agricultural activities or gardening were evaluated by Monte Carlo simulation in the case that the compost was polluted by Salmonella spp., E . coli O157:117 and Poliovirus 1 . Criteria satisfying the acceptable risk (less than 10(-4) per year) for these pathogenic bacteria and virus in the compost were determined from the result of simulations . 1.0 {CFU or PFU/g-wet} was available as the criteria for E . coli O157 and Poliovirus 1 in the compost . On the other hand, the criterion for Salmonella spp . in the compost should be established on a lower concentration than 0.001 CFU/g-wet.

Microb Drug Resist, 2002 Winter, 8(4), 375 - 83
Phenotypic and genotypic characterization of food animal isolates of Salmonella with reduced sensitivity to ciprofloxacin; Allen KJ et al.; Reports of nontyphoidal Salmonella enterica subsp . enterica showing reduced sensitivity to ciprofloxacin (RSC) have increased rapidly during the past decade . Infection in humans with Salmonella possessing RSC may compromise the effectiveness of ciprofloxacin therapy . Nineteen among 4,357 Salmonella strains isolated from food animals in Canada from 1998 to 1999 showed RSC; 17 were from turkeys and 2 from chickens . All were resistant to nalidixic acid and sulfisoxazole and possessed RSC at a level of 0.125-0.5 microg/ml . PCR-RFLP of the gyrA quinolone resistance-determining region (QRDR) with Hinfl revealed that S . Bredeney and S . Heidelberg isolates possessed a mutation in this region . Single-strand conformational polymorphism (SSCP) analysis showed that S . Schwarzengrund and S . Senftenberg isolates also possessed a point mutation in the QRDR . DNA sequencing confirmed the findings and showed that all isolates possessed a base substitution in the gyrA QRDR . Sequencing revealed no mutations in the gyrB and silent wobble mutations in the parC QRDR . Reserpine, a known efflux pump inhibitor, did not effect the MICs for ciprofloxacin, nalidixic acid, and tetracycline . The mar operon could be induced in all isolates at 37 degrees C and in 18 of 19 at 30 degrees C; induction resulted in a two- to four-fold increase in the MIC of ciprofloxacin . In 14 of the 19 isolates, the mutation rate was two-fold or higher than in a ciprofloxacin sensitive S . Bredeney and S . Typhimurium LT2 control strain . Examination of clonal relatedness using pulsed-field gel electrophoresis (PFGE) and plasmid profiles indicated that some degree of clonal dispersion may have occurred, but the majority of isolates may have arisen from de novo mutations.

Microb Drug Resist, 2002 Winter, 8(4), 345 - 53
WHO global salm-surv external quality assurance system (EQAS): an important step toward improving the quality of Salmonella serotyping and antimicrobial susceptibility testing worldwide; Petersen A et al.; Initiated in 2000, WHO Global Salm-Surv is a global network of epidemiologists and microbiologists involved in Salmonella surveillance . WHO Global Salm-Surv seeks to enhance the capacity of national and regional reference laboratories to conduct Salmonella serotyping and antimicrobial susceptibility testing through international training courses and an External Quality Assurance System (EQAS) . In 2000, 44 WHO Global Salm-Surv member laboratories from 35 countries determined the serotype and antimicrobial susceptibility pattern for eight "blinded" Salmonella isolates . For serotyping, 73% of the results were correct . For susceptibility testing, 92% of the results were in agreement with the expected results . However, only 78% of the performed tests with the E . coli ATCC 25922 reference strain were within the quality control range specified by National Committee for Clinical Laboratory Standards (NCCLS) guidelines . These EQAS results demonstrate the need for further training to improve the performance of some of the laboratories . WHO Global Salm-Surv activities, including international training courses and EQAS, represent an important step toward improving the quality of Salmonella serotyping and antimicrobial susceptibility testing worldwide, and improving the current reliability and comparability of Salmonella surveillance data obtained from different countries,

Microb Drug Resist, 2002 Winter, 8(4), 281 - 9
The AcrB multidrug transporter plays a major role in high-level fluoroquinolone resistance in Salmonella enterica serovar typhimurium phage type DT204; Baucheron S et al.; Salmonella enterica serovar Typhimurium phage type DT204 strains isolated from cattle and animal feed in Belgium were characterized for high-level fluoroquinolone resistance mechanisms {MICs to enrofloxacin (Enr) and ciprofloxacin (Cip), 64 and 32 microg/ml, respectively} . These strains isolated during the periods 1991-1994, and in 2000 were clonally related as shown by pulsed-field gel electrophoresis (PFGE) . Selected strains studied carried several mutations in the quinolone target genes, i.e., a double mutation in the quinolone resistance-determining region (QRDR) of gyrA leading to amino acid changes Ser83Ala and Asp87Asn, a single mutation in the QRDR of gyrB leading to amino acid change Ser464Phe, and a single mutation in the QRDR of parC leading to amino acid change Ser80Ile . Moreover, Western blot analysis showed overproduction of the AcrA periplasmic protein belonging to the AcrAB-ToIC efflux system . This suggested active efflux as additional resistance mechanism resulting in a multiple antibiotic resistance (MAR) phenotype, which was measurable by an increased level of resistance to the structurally unrelated antibiotic florfenicol in the absence of the specific floR resistance gene . The importance of the AcrAB-TolC efflux system in high-level fluoroquinolone resistance was further confirmed by inactivating the acrB gene coding for the multidrug transporter . This resulted in a 32-fold reduction of resistance level to Enr (MIC = 2 microg/ml) and actually in a susceptible phenotype according to clinical breakpoints . Thus, AcrB plays a major role in high-level fluoroquinolone resistance, even when multiple target gene mutations are present . The same effect was obtained using the recently identified efflux pump inhibitor (EPI) Phe-Arg-naphthylamide also termed MC207,110 . Among several fluoroquinolones tested in combination with EPI, the MIC of Enr was reduced most significantly . Thus, using EPI together with fluoroquinolones such as Enr may be promising in combination therapy against high-level fluoroquinolone-resistant S . enterica serovar Typhimurium.

Am J Ther, 2003 Jan-Feb, 10(1), 32 - 9
Lysis of salmonella typhi intracellularly infected U937 cells by human natural killer cells: effect of protein kinase inhibitors; Miranda D et al.; We examined the effect of Salmonella typhi (wild-type Ty2 and mutant strain TYT1231)-infected U937 cells on natural killer cell (NKC) cytotoxicity of peripheral blood mononuclear cells (PBMCs) and highly purified NKC (HPNKCs; CD16(+)/CD56(+) > 95%; the rest corresponding to CD3(+) T cells) . We also analyzed the possible role of various protein kinases involved in natural cytotoxicity on these processes . PBMC cytotoxicity against S typhi-infected U937 cells was significantly higher (paired Student t test; P < 0.05) than its lytic effect against noninfected cells (control) at the various effector-to-target cell ratios used (30:1 {24.4 +/- 9.7, 25.1 +/- 11.8, and 17.5 +/- 8.6}; 50:1 {26.6 +/- 9.7, 26.7 +/- 12.8, and 21.2 +/- 7.5} and 70:1 {32.4 +/- 14.4, 30.1 +/- 12.4, and 23.1 +/- 7.2}, respectively) . PBMC NKC activity seemed to be dependent on such ratios and was similar against both Salmonella strains studied . Approximately half of the individual samples tested (n = 12; 8 male and 4 female subjects of comparable age) showed at least a 20% specific lysis increase against their own control; essentially no changes or smaller increases in NKC activity were observed in all other samples . Similar results were obtained using HPNKCs as effector cells (5:1 ratio {38.9 +/- 12.3, 43.3 +/- 11.2, and 27.5 +/- 4.9} and 10:1 ratio {51.3 +/- 9.1, 46.1 +/- 9.8, and 37.7 +/- 15.5, respectively}) . In general, specimens significantly lysed after incubation with PBMCs responded in a similar manner to a challenge with HPNKCs . PBMC and HPNKC cytotoxicity against S typhi wild-type-infected U937 cells was significantly decreased in a dose-dependent manner by the addition of genistein (50-200 micromol) or GFX (0.5-2.0 micromol) to the cytotoxicity assay mixture . NKC activity was almost completely inhibited at the highest genistein and GFX concentrations . In similar experiments, wortmannin (100-500 nmol) failed to inhibit PBMC cytotoxicity and significantly decreased HPNKC activity only at the highest concentration tested . These results show that in the process of NKC recognition and lysis of S typhi-infected U937 cells, there is not a requisite for full bacterial intracellular survival capacity and that S typhi-infected U937 cells are a significantly better target than noninfected U937 cells . NKC signaling pathways activated during the S typhi-infected U937 cell recognition and lysis process are mainly protein tyrosine kinase and protein kinase-C, and they can be blocked by the same protein kinase inhibitors known to inhibit natural cytotoxicity.

Curr Treat Options Neurol, 2003 Jan, 5(1), 13 - 22
Subdural Empyema; Greenlee JE; Subdural empyema represents loculated infection between the outermost layer of the meninges, the dura, and the arachnoid . The empyema may develop intracranially or in the spinal canal . Intracranial subdural empyema is most frequently a complication of sinusitis or, less frequently, otitis or neurosurgical procedures . Spinal subdural empyema is rare and may result from hematogenous infection or spread of infection from osteomyelitis . The most common organisms in intracranial subdural empyema are anaerobic and microaerophilic streptococci, in particular those of the Streptococcus milleri group (S . milleri and Streptococcus anginosus) . Staphylococcus aureus is present in a minority of cases, and multiple additional organisms, including Gram-negative organisms, such as Escherichia coli, and anaerobic organisms, such as Bacteroides, may be present . Pseudomonas aeruginosa or Staphylococcus epidermidis may be present in cases related to neurosurgical procedures, and Salmonella species have been detected in patients with advanced AIDS; multiple organisms may be present simultaneously . Spinal subdural empyemas are almost invariably caused by streptococci or by S . aureus . Subdural empyema--whether it occurs in the skull or the spinal canal--may cause rapid compression of the brain or spinal cord, and represents an extreme medical and neurosurgical emergency . The diagnostic procedure of choice for intracranial and spinal subdural empyema is MRI with gadolinium enhancement . Computed tomography scan may miss intracranial subdural empyemas detectable by MRI . Conversely, occasion spinal subdural empyemas may be detected by CT myelography where MRI is negative . Treatment in virtually all cases of intracranial or spinal subdural empyema requires prompt surgical drainage and antibiotic therapy . Pus from the empyema should always be sent for anaerobic, as well as aerobic, culture . Because intracranial subdural empyemas may contain multiple organisms, provisional antibiotic therapy of intracranial subdural empyema, where the organism is unknown, should be directed against S . aureus, microaerophilic and anaerobic streptococci, and Gram-negative organisms . Antibiotics should include 1) nafcillin, oxacillin, or vancomycin; plus 2) a third generation cephalosporin; plus 3) metronidazole . Provisional antibiotic therapy of spinal subdural empyemas should be directed against S . aureus and streptococci, and should include nafcillin, oxacillin, or vancomycin . Morbidity and mortality in intracranial and spinal subdural empyema relate directly to the delay in institution of therapy . Both conditions should, thus, be treated with great urgency.

Clin Exp Immunol, 2003 Jan, 131(1), 111 - 7
Th1 and Th1-inducing cytokines in Salmonella infection; Mizuno Y et al.; Thl and Thl-inducing cytokines and T cell responses were investigated in human salmonellosis . Serum IFN-gamma, IL-12 and IL-18 levels were increased significantly in patients with salmonellosis . The increase in serum IL-15 and IL-18 levels was more significant and prolonged in patients with the systemic form of salmonellosis than in those with the gastroenteric form . The serum IFN-gamma level was correlated significantly with IL-12 and IL18 levels, and the IL-15 level was correlated significantly with IL-18 . Upon stimulation with Salmonella in vitro, mononuclear cells from salmonellosis patients produced significantly higher amounts of IFN-gamma and IL-12 compared with those from healthy controls . Anti-IL-12 moAb or anti-IL18 MoAb significantly inhibited Salmonella-induced IFN-gamma production in vitro . gamma delta T cells expressed significantly higher levels of IFN-gamma mRNA in salmonellosis patients than in healthy controls . The results suggest that Th1-inducing cytokines appear to be involved in the in vivo response against Salmonella infection, promoting IFN-gamma production by alpha beta and gamma delta T cells which plays a protective role against Salmonella.

Clin Microbiol Infect, 2002 Dec, 8(12), 810 - 3
In vitro effects of cefotaxime and ceftriaxone on Salmonella typhi within human monocyte-derived macrophages; Ekinci B et al.; The main objective of this in vitro study was to assess the effects of cefotaxime and ceftriaxone in killing Salmonella typhi in infected human macrophages . Human monocyte-derived macrophages isolated from peripheral blood of human volunteers were cultured in vitro for macrophage differentiation, and subsequently infected with S . typhi strains (a clinical isolate and a standard strain TA-42) at a cell ratio of 10 : 1 . MICs of cefotaxime and ceftriaxone were determined by broth microdilution, and the antibiotics were included in the culture medium at one and five times their MIC values . Samples of cell culture medium taken at 0, 3, 6 and 24 h of incubation were cultured for growth of S . typhi on nutrient agar . Gentamicin (10 mg/L) was included in each well except for the control wells, in order to prevent growth of extracellular S . typhi . Both antibiotics showed good in vitro antibacterial effects against S . typhi strains . There were no statistically significant differences between the extracellular and intracellular effects of antibiotics with regard to elimination of the bacteria . Cefotaxime and ceftriaxone are highly effective against extracellular bacterial growth . The results of our in vitro experiments suggest that cefotaxime and ceftriaxone might also be used clinically against susceptible intracellular pathogens such as S . typhi.

What Is Genetic Engineering?, What Is Biofilm?, What Is Cell Biology?, What Is Bioengineering?, What Is Bioreactor?, o, Bacteriology, i, Bacterium, n, Bacteria, r, Microbes, c, Microorganism, o, Culture medium, n, Antimicrobials, s, S. cerevisiae, o, Minimum inhibiting concentration, n, Microbial, s, Yeasts, e, Escherichia coli, o, Staphylococcus aureus, o, Fermentations, a, Geobacilli, a, Yeasts, n, Lactococci, a, Escherichia coli, s, Water treatment, n, Azithromycin, s, Rhizobacterium, s, Penicillin, e, Vibriosis, n, Beta lactamase, e, Yeasts, c, Geobacilli

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