Salmonella

J Food Prot, 2004 Dec, 67(12), 2661 - 5
Temperature and biological soil effects on the survival of selected foodborne pathogens on a mortar surface; Allan JT et al.; The survival of three foodborne pathogens (Listeria monocytogenes, Yersinia enterocolitica, and Salmonella) attached to mortar surfaces, with or without biological soil (porcine serum) and incubated at either 4 or 10 degrees C in the presence of condensate, was evaluated . Soiled and unsoiled coupons were inoculated by immersion into a five-strain cocktail (approximately 10(7) CFU/ml) of each organism type and evaluated . Coupons were incubated at 25 degrees C for 2 h to allow attachment of cells, rinsed to remove unattached cells, and incubated at either 4 or 10 degrees C at high humidity to create condensate on the surface . Sonication was used to remove the attached cells, and bacteria (CFU per coupon) was determined at 9 to 10 sampling periods over 120 h . Yersinia populations decreased more than 5 log units in the presence of serum in a 24-h period . Listeria and Salmonella had better survival on mortar in the presence of serum than Yersinia throughout the 120-h incubation period . Populations of L . monocytogenes declined more rapidly at 10 than at 4 degree C after 24 h . In general, differences in temperature did not affect the survival of Salmonella or Yersinia . Serum had a protective effect on the survival of all three organisms, sustaining populations at significantly (P < or = 0.05) higher numbers over time than on corresponding unsoiled coupons . There were no significant differences (P > 0.05) among the mean number (CFU per coupon) of L . monocytogenes, Y . enterocolitica, or Salmonella on initial attachment onto the mortar surfaces (unsoiled) . The results indicate relatively rapid destruction of selected pathogenic bacteria on unsoiled mortar surfaces compared with those that contained biological soil, thus highlighting the need for effective cleaning to reduce harborage of these microbes in the food factory environment.

Microbiology, 2005 Jan, 151(Pt 1), 209 - 18
The formation of cyclopropane fatty acids in Salmonella enterica serovar Typhimurium; Kim BH et al.; The formation of cyclopropane fatty acid (CFA) and its role in the acid shock response in Salmonella enterica serovar Typhimurium (S . typhimurium) was investigated . Data obtained by GC/MS demonstrated that the CFA level in S . typhimurium increased upon its entry to the stationary phase, as in other bacteria . The cfa gene encoding CFA synthase was cloned, and mutants of the cfa gene were constructed by allelic exchange . A cfa mutant could not produce CFA and was sensitive to low pH . Introduction of a functional cfa gene into a cfa mutant cell made the mutant convert all unsaturated fatty acids to CFAs and partially restored resistance to low pH . Interestingly, the alternative sigma factor RpoS, which was induced during the stationary phase, affected the production of C(19) CFA but not C(17) CFA . Western blotting analysis showed that the increase in expression of CFA synthase at early stationary phase was due to the alternative sigma factor RpoS.

Microbiology, 2005 Jan, 151(Pt 1), 5 - 14
Gene expression diversity among Mycobacterium tuberculosis clinical isolates; Gao Q et al.; Intraspecies genetic diversity has been demonstrated to be important in the pathogenesis and epidemiology of several pathogens, such as HIV, influenza, Helicobacter and Salmonella . It is also important to consider strain-to-strain variation when identifying drug targets and vaccine antigens and developing tools for molecular diagnostics . Here, the authors present a description of the variability in gene expression patterns among ten clinical isolates of Mycobacterium tuberculosis, plus the laboratory strains H37Rv and H37Ra, growing in liquid culture . They identified 527 genes (15 % of those tested) that are variably expressed among the isolates studied . The remaining genes were divided into three categories based on their expression levels: unexpressed (38 %), low to undetectable expression (31 %) and consistently expressed (16 %) . The expression categories were compared with functional categories and three biologically interesting gene lists: genes that are deleted among clinical isolates, T-cell antigens and essential genes . There were significant associations between expression variability and the classification of genes as T-cell antigens, involved in lipid metabolism, PE/PPE, insertion sequences and phages, and deleted among clinical isolates . This survey of mRNA expression among clinical isolates of M . tuberculosis demonstrates that genes with important functions can vary in their expression levels between strains grown under identical conditions.

J Bacteriol, 2005 Jan, 187(2), 758 - 64
Structural and Genetic Characterization of Enterohemorrhagic Escherichia coli O145 O Antigen and Development of an O145 Serogroup-Specific PCR Assay; Feng L et al.; Enterohemorrhagic Escherichia coli O145 strains are emerging as causes of hemorrhagic colitis and hemolytic uremic syndrome . In this study, we present the structure of the E . coli O145 O antigen and the sequence of its gene cluster . The O145 antigen has repeat units containing three monosaccharide residues: 2-acetamido-2-deoxy-d-glucose (GlcNAc), 2-acetamidoylamino-2,6-dideoxy-l-galactose, and N-acetylneuraminic acid . It is very closely related to Salmonella enterica serovar Touera and S . enterica subsp . arizonae O21 antigen . The E . coli O145 gene cluster is located between the JUMPStart sequence and the gnd gene and consists of 15 open reading frames . Putative genes for the synthesis of the O-antigen constituents, for sugar transferase, and for O-antigen processing were annotated based on sequence similarities and the presence of conserved regions . The putative genes located in the E . coli O145 O-antigen gene cluster accounted for all functions expected for synthesis of the structure . An E . coli O145 serogroup-specific PCR assay based on the genes wzx and wzy was also developed by screening E . coli and Shigella isolates of different serotypes.

Diagn Microbiol Infect Dis, 2005 Jan, 51(1), 73 - 6
Salmonella enterica serovar Kedougou contamination of commercially grown mushrooms; Doran G et al.; During investigation of an episode of Salmonella enterica serovar Kedougou contamination of mushrooms, multiple closely related isolates were obtained from mushrooms and mushroom-growing materials . Contamination apparently originated from sugar beet lime, an alkaline material used in mushroom growing . No associated cases of human infection were detected.

Medicina (B Aires), 2004, 64(2), 120 - 4
{Surveillance of foodborne diseases in the province of Rio Negro, Argentina, 1993-2001}; Di Pietro S et al.; A total of 39 outbreaks of foodborne diseases affecting 958 people in the province of Rio Negro, Argentina between 1993 and 2001 are described and evaluated . The main causal agents were identified involving food, sites of occurrence, risk factors and notification system used . Salmonella spp (38%), Trichinella spiralis (15%), Escherichia coli (13%) and Staphylococcus aureus (15%) were the most frequent agents present in outbreaks . Salmonella spp produced the largest number of cases (52%) . Food involved were cooked meat (36%), cheese (10%), sandwiches (10%), deserts (10%) and ice cream (8%) . Indeed, ice creams were involved in the largest number of cases and of people affected . In relation to the source of food, 41% of outbreaks were caused by homemade meals, 23% by catering or ice cream parlor, 13% in family parties, 8% in county fairs and 8% in hotel restaurants . In 28% of the outbreaks the etiological agent was identified exclusively by epidemiological analysis, in 64% isolation of the agent was carried out, and in 8% of the cases, a final diagnosis could not be obtained . Validity of epidemiological studies in foodborne disease, the necessity of strengthening the notification system of outbreaks, and the importance of good practices in food handling are analyzed.

Vet Microbiol, 2005 Jan 31, 105(2), 113 - 22 Epub 2004 Dec 19.
Antibacterial effects of the Cu(II)-exchanged montmorillonite on Escherichia coli K88 and Salmonella choleraesuis; Tong G et al.; The aim of this research was to determine the antibacterial properties and mechanisms of Cu(II)-exchanged montmorillonite (MMT-Cu) in vitro . Escherichia coli ATCC K88 and Salmonella choleraesuis ATCC 50020 were chosen as indicators of intestinal tract pathogenic bacteria in weanling pigs . The antibacterial activity of MMT-Cu and MMT were evaluated by determining the minimum inhibitory concentrations (MICs) using two-fold serial dilutions in MH broth, and the amount of Cu(2+) released into the broth was measured by an atomic absorption technique . The rate of oxygen consumption was measured using a SP-II-type oxygen electrode analyzer; the structural integrity of cell walls of bacteria was observed by transmission electron microscope (TEM); enzymatic activity of bacteria was examined with a semi-automatic biochemical analyzer . The results showed that MMT-Cu inhibited the growth of E . coli K88 and S . choleraesuis, and the MICs were 1024 and 2048mug/ml, respectively . The amount of Cu(2+) released into the broth was in the range 6.51-45.65mug/ml . Nevertheless, both tested bacteria still grew in broth containing 32,768mug/ml of MMT . Treatment with MMT-Cu could lead to significant release of intracellular enzymes from the tested bacteria . Data from oxygen consumption of bacteria showed that MMT-Cu could inhibit the TCA pathway of the bacterial respiration metabolism . These results show that MMT-Cu has an antibacterial activity.

Vet Microbiol, 2005 Jan 31, 105(2), 93 - 101 Epub 2004 Dec 19.
Protection of laying hens against Salmonella Enteritidis by immunization with type 1 fimbriae; De Buck J et al.; Eighteen chickens were immunized subcutaneously with purified type 1 fimbriae from Salmonella enterica serotype Enteritidis at 18 and 21 weeks of age . Evidence of IgG and IgA responses was found in the eggs and in the sera of the immunized hens . Three weeks later, immunized and non-immunized chickens (n=18) were challenged intravenously with 2x10(7) live Salmonella enterica serotype Enteritidis . There was no significant difference in the numbers of eggs laid by immunized and non-immunized birds . The percentage of Salmonella contaminated eggs was significantly higher in the non-immunized group than in the immunized group due to a higher percentage of contamination of the externally disinfected egg shells . There were no statistical differences in the percentages of contaminated yolks and egg whites between control and immunized birds . No differences in the number of colonizing bacteria could be found in the spleen nor in the liver between the immunized and the control groups throughout the experiment . Salmonella was cleared from the ovary of the immunized birds in the second week p.i., in contrast to the control birds where Salmonella was isolated till the third week after infection . Oviducts were significantly more infected in the control group than in the immunized group . Salmonella was cleared from the oviducts at 3 weeks p.i . in the immunized hens but not in the control hens . In conclusion, we demonstrated that the immunization of laying hens with type 1 fimbriae reduced the number of contaminated eggs and reduced the colonization of the reproductive organs.

Neurol India, 2004 Oct, 52(4), 499 - 500
Salmonella spinal osteomyelitis: A case report and review of literature; Acharya S et al.; A case of vertebral osteomyelitis is presented where initial presumptive diagnosis of tuberculous infection was made on clinico-radiological grounds but eventually turned out to be Salmonella infection upon exploration, biopsy and culture . Patient recovered completely following debridement and appropriate antibiotics (fluoro-quinolones) for a period of six weeks . Internal fixation allowed early ambulation.

J Biochem (Tokyo), 2004 Oct, 136(4), 517 - 524
Overexpression and Characterization of an Aminoglycoside 6'-N-Acetyltransferase with Broad Specificity from an {varepsilon}-Poly-L-lysine Producer, Streptomyces albulus IFO14147; Hamano Y et al.; Streptomyces albulus IFO14147 produces epsilon-poly-l-lysine, which exhibits antimicrobial activity . In the MIC studies with antibiotics, S . albulus IFO14147 was shown to be resistant to kanamycin and amikacin, which are aminoglycoside (AG) antibiotics . We report here the isolation of the AG-resistance gene from S . albulus IFO14147 and the substrate specificity of the gene product, AAC(6')-Isa, which catalyzes N-acetylation at the 6' position of AGs, thereby inactivating them . Kinetic studies revealed that this enzyme has remarkably wide substrate specificity . The V(max)/K(m) values determined for AGs vary by a factor of up to 6,300, a much wider range than those observed for the AAC(6')s from Enterococcus faecium {AAC(6')-Ii} and Salmonella enteritidis {AAC(6')-Iy} . In addition, AAC(6')-Isa was able to acetylate lividomycin A, which has a hydroxy group at the 6' position . Enzymatically acetylated lividomycin A was found to be highly susceptible to mild base hydrolysis, suggesting that the enzyme also catalyzes O-acetyltransfer.

FEMS Microbiol Lett, 2005 Jan 15, 242(2), 305 - 12
The presence of the tet gene from cloning vectors impairs Salmonella survival in macrophages; Abromaitis S et al.; Cloning, mutagenesis and complementation of virulence factors are key steps to understand the mechanisms of bacterial pathogenesis and cloning vectors are routinely utilized for these processes . We have investigated the effect of the presence of commonly used cloning vectors on the survival of the intracellular bacterial pathogen Salmonella during macrophage infection . We demonstrate that the presence of the pSC101 derived tetracycline resistance gene on plasmids causes a lower survival rate of Salmonella in macrophages . The decrease in survival caused by the presence of the tet gene was not due to a higher susceptibility to gentamicin, a growth defect, or to increased sensitivity to acid . Higher susceptibility to hydrogen peroxide was observed in vitro for strain containing plasmid with the tet gene when the strains were grown at high densities but not when they were grown at low densities . Our findings demonstrate that the use of the tet gene for mutation or complementation can have deleterious effects and should thus be carefully considered.

Food Chem Toxicol, 2005 Feb, 43(2), 247 - 52
Evaluation of beta-myrcene, alpha-terpinene and (+)- and (-)-alpha-pinene in the Salmonella/microsome assay; Gomes-Carneiro MR et al.; This study was undertaken to investigate the genotoxicity of beta-myrcene, alpha-terpinene and (+) and (-)-alpha-pinene, monoterpenes found in a variety of plant volatile oils . beta-myrcene, alpha-terpinene and alpha-pinene as well as plant oils containing these hydrocarbon monoterpenes have been used as flavoring additives in foods and beverages, as fragrances in cosmetics, and as scent in household products . Mutagenicity was evaluated by the Salmonella/microsome assay (TA100, TA98, TA97a and TA1535 tester strains), without and with addition of an extrinsic metabolic activation system (rat liver S9 fraction induced by Aroclor 1254) . Two dose-complementary assays were performed so that a broad range of doses, including a number of regularly-spaced doses in the non-toxic dose interval, were tested . No increase in the number of his(+) revertant colonies over the negative control values was observed in any of the four S . typhimurium tester strains . Results from the present study therefore indicated that beta-myrcene, alpha-terpinene, and (+) and (-)-alpha-pinene are not mutagenic in the Ames test.

Food Chem Toxicol, 2005 Feb, 43(2), 233 - 8
Safety and efficacy evaluation of aqueous citric acid to degrade B-aflatoxins in maize; Mendez-Albores A et al.; Chemical inactivation of aflatoxin B(1) (AFB(1)) and aflatoxin B(2) (AFB(2)) in maize grain by means of 1N aqueous citric acid was confirmed by the AFLATESTtrade mark immunoaffinity column method, high performance liquid chromatography (HPLC), and the Ames test (Salmonella-microsomal screening system) . The AFLATESTtrade mark assay showed that aflatoxins in the maize grain with an initial concentration of 29ng/g were completely degraded and 96.7% degradation occurred in maize contaminated with 93ng/g when treated with the aqueous citric acid . Aflatoxin fluorescence strength of acidified samples was much weaker than untreated samples as observed in HPLC chromatograms . On the other hand, the Ames test results indicated that the mutagenic activity of acidified samples was greatly reduced compared with that of untreated samples based on his(-)-->his(+) reversions in the Salmonella TA100 strain . Chemical inactivation appears to be a promising method of removing aflatoxin from food commodities.

Vet Immunol Immunopathol, 2005 Feb 10, 103(3-4), 155 - 61
Protection of gnotobiotic pigs against Salmonella enterica serotype Typhimurium by rough mutant of the same serotype is accompanied by the change of local and systemic cytokine response; Splichal I et al.; We have demonstrated that severe systemic disease caused by virulent LT2 strain Salmonella enterica serotype Typhimurium in gnotobiotic piglets can be alleviated by oral inoculation with an avirulent rough (R) mutant of the same serotype 24h before challenge with the virulent strain . Protected piglets had no signs of enteritis . The concentrations of TNF-alpha, IL-1beta, IL-8 and IL-10 were measured by ELISA in ileal washings and plasma of uninfected and infected pigs . The cytokines were not detected in plasma of germ-free piglets, and low concentrations of IL-1beta and IL-8 were found in their ileal washings . The pre-inoculation of the rough mutant induced an increase in IL-8 and decrease in IL-1beta and IL-10 in plasma . The virulent LT2 strain induced very high TNF-alpha concentrations in the ileum which were reduced in the pigs pre-inoculated with the R mutant.

Int J Antimicrob Agents, 2005 Jan, 25(1), 38 - 43
Increasing prevalence of multidrug-resistant non-typhoidal salmonellae, Kenya, 1994-2003; Kariuki S et al.; Over the last decade there has been a steady increase in the proportion of multidrug resistance among non-typhoidal salmonellae (NTS) isolated from adult patients with bacteraemia in Kenya . The prevalence of NTS multiply resistant to all commonly available drugs including ampicillin, streptomycin, co-trimoxazole, chloramphenicol and tetracycline rose from 31% in 1994 to 42% at present, with concomitantly higher MICs of each drug . Resistance is encoded on large self-transferable 100-110kb plasmids . Pulsed field gel electrophoresis of XbaI and SpeI digested chromosomal DNA revealed three main digest patterns for Salmonella enterica serotype Typhimurium and two main patterns for Salmonella enterica serotype Enteritidis . Although the genotypes of NTS remained fairly stable over the last decade, the large increase in MICs of all commonly used drugs and increased MICs of ciprofloxacin, poses a major challenge for treatment of invasive NTS infection.

Int J Antimicrob Agents, 2005 Jan, 25(1), 31 - 7
Mechanisms of resistance in Salmonella enterica adapted to erythromycin, benzalkonium chloride and triclosan; Braoudaki M et al.; The potential for adaptive resistance of S . enterica serovar Enteritidis, Typhimurium and Virchow to increasing sub-lethal concentrations of erythromycin, benzalkonium chloride and triclosan was investigated to identify mechanisms underlying resistance . Permeability changes of the outer membrane, including LPS, cell surface charge, hydrophobicity and the presence of an active efflux in the adapted strain compared with the parent were studied . Examination of the outer membrane and LPS did not reveal any significant changes, although most of the pre-adapted strains were notably less hydrophobic than resistant strains . More than one type of active efflux was identified in all strains investigated, on the basis of restored sensitivity in the presence of the inhibitors reserpine and carbonyl cyanide 3-chlorophenylhydrazone (CCCP) . Cell surface hydrophobicity and the presence of active efflux could contribute to the resistance of S . enterica to the antibacterial agents studied here.

J Theor Biol, 2005 Mar 21, 233(2), 159 - 75 Epub 2004 Nov 10.
Understanding the dynamics of Salmonella infections in dairy herds: a modelling approach; Xiao Y et al.; There is evidence of variation in the infection dynamics of different Salmonella serotypes in cattle-ranging from transient epidemics to long term persistence and recurrence . We seek to identify possible causes of these differences . In this study we present mathematical models which describe both managed population dynamics and epidemiology and use these to investigate the effects of demographic and epidemiological factors on epidemic behaviour and threshold for invasion . In particular, when the system is perturbed by higher culling or pathogen-induced mortality we incorporate mechanisms to constrain the lactating herd size to remain constant in the absence of pathogen or to lie within a fairly small interval in the presence of pathogen . A combination of numerical and analytical techniques is used to analyse the models . We find that the epidemiologically dominating management group can change from the dry/lactating cycle to the weaned group with increasing culling rate . Pseudovertical transmission is found to have little effect on the invasion criteria, while indirect transmission has significant influence . Pathogen-induced mortality, recovery, immune response and pathogen removal are found to be factors inducing damped oscillations; variation in these factors between Salmonella serotypes may be responsible for some of the observed differences in within herd dynamics . Specifically, higher pathogen-induced mortality, shorter infectious period, more persistent immune response and more rapid removal of faeces result in a lower number of infectives and smaller epidemics but a greater tendency for damped oscillations.

Infect Immun, 2005 Jan, 73(1), 459 - 63
Effect of inactivation of degS on Salmonella enterica serovar typhimurium in vitro and in vivo; Rowley G et al.; The alternative sigma factor (RpoE sigma(E)) enables Salmonella enterica serovar Typhimurium to adapt to stressful conditions, such as oxidative stress, nutrient deprivation, and growth in mammalian tissues . Infection of mice by Salmonella serovar Typhimurium also requires sigma(E) . In Escherichia coli, activation of the sigma(E) pathway is dependent on proteolysis of the anti-sigma factor RseA and is initiated by DegS . DegS is also important in order for E . coli to cause extraintestinal infection in mice . We constructed a degS mutant of the serovar Typhimurium strain SL1344 and compared its behavior in vitro and in vivo with those of its wild-type (WT) parent and an isogenic rpoE mutant . Unlike E . coli degS strains, the Salmonella serovar Typhimurium degS strain grew as well as the WT strain at 42 degrees C . The degS mutant survived very poorly in murine macrophages in vitro and was highly attenuated compared with the WT strain for both the oral and parenteral routes of infection in mice . However, the degS mutant was not as attenuated as the serovar Typhimurium rpoE mutant: 100- to 1,000-fold more degS bacteria than rpoE bacteria were present in the livers and spleens of mice 24 h after intraperitoneal challenge . In most assays, the rpoE mutant was more severely affected than the degS mutant and a sigma(E)-dependent reporter gene was more active in the degS mutant than the rpoE strain . These findings indicate that degS is important for activation of the sigma(E) pathway in serovar Typhimurium but that alternative pathways for sigma(E) activation probably exist.

Infect Immun, 2005 Jan, 73(1), 362 - 8
Optimization of Salmonella enterica serovar typhi DeltaaroC DeltassaV derivatives as vehicles for delivering heterologous antigens by chromosomal integration and in vivo inducible promoters; Stratford R et al.; Novel candidate live oral vaccines based on a Salmonella enterica serovar Typhi ZH9 (Ty2 DeltaaroC DeltassaV) derivative that directed the expression of either the B subunit of Escherichia coli heat-labile toxin or hepatitis B virus core antigen from the bacterial chromosome using the in vivo inducible ssaG promoter were constructed . The levels of attenuation of the two S . enterica serovar Typhi ZH9 derivatives were similar to that of the parent as assessed by measuring the replication of bacteria within human macrophage-like U937 cells . The expression of heterologous antigen in the respective S . enterica serovar Typhi ZH9 derivatives was up-regulated significantly within U937 cells compared to similar S . enterica serovar Typhi ZH9 derivative bacteria grown in modified Luria-Bertani broth supplemented with aromatic amino acids . Immunization of mice with these S . enterica serovar Typhi ZH9 derivatives stimulated potent antigen-specific serum immunoglobulin G responses to the heterologous antigens.

Infect Immun, 2005 Jan, 73(1), 334 - 41
Salmonella pathogenicity island 2-mediated overexpression of chimeric SspH2 proteins for simultaneous induction of antigen-specific CD4 and CD8 T cells; Panthel K et al.; Salmonella enterica serovar Typhimurium employs two different type III secretion systems (TTSS) encoded within Salmonella pathogenicity islands 1 and 2 (SPI1 and SPI2) for targeting of effector proteins into the cytosol of eukaryotic cells during different stages of the infection cycle . The SPI1 TTSS translocates virulence factors across the plasma membrane when the bacterium initially contacts the host cell . In contrast, the SPI2 TTSS functions to translocate proteins across the membrane of the Salmonella-containing vacuole and promotes intracellular survival and replication . The aim of the present study was to directly compare the potentials of SPI1 and SPI2 type III effector proteins to act as carrier molecules for a heterologous antigen . The p60 protein of Listeria monocytogenes was used as a model antigen to construct chimeric SopE2 (SPI1), SifA (SPI2), and SspH2 (SPI2) proteins . SPI1- and SPI2-dependent up- and down-regulation of hybrid gene expression led to sequential translocation of p60 fusion proteins into the cytosol of Salmonella-infected macrophages . Mice orally immunized with recombinant Salmonella strains expressing these hybrid proteins revealed comparable numbers of p60-specific CD8 T cells . However, only overexpression of translocated SspH2/p60 from a medium-copy-number vector induced simultaneous antigen-specific CD4 and CD8 T-cell responses, suggesting that SspH2 is an attractive carrier molecule for foreign-protein delivery.

Infect Immun, 2005 Jan, 73(1), 317 - 24
Enhanced immunoglobulin A response and protection against Salmonella enterica serovar typhimurium in the absence of the substance P receptor; Walters N et al.; The development of the neurokinin-1 receptor-deficient (NK1R(-/-)) mouse permitted inquiry into the regulation of secretory immunoglobulin A (S-IgA) responses by substance P (SP) after oral immunization with a Salmonella enterica serovar Typhimurium vector expressing colonization factor antigen I (CFA/I) from enterotoxigenic Escherichia coli . In NK1R(-/-) mice, mucosal and serum IgA anti-CFA/I fimbrial responses were augmented, while secreted IgG anti-CFA/I fimbrial responses remained unaffected compared to those of BALB/c (NK1R(+/+)) mice . Supportive antibody-forming cells were present in the small intestinal lamina propria and spleen . To gain insight as to why the augmented S-IgA responses occurred, minimally, the responses were not attributed to differences in vaccine colonization of Peyer's patch (PP) and spleen or in their respective tissue weights . However, these S-IgA responses were supported by increased numbers of PP CD4(+) T helper (Th) cells secreting interleukin-5 (IL-5) and IL-6 and splenic CD4(+) Th cells secreting IL-6 compared to NK1R(+/+) mice . Challenge of naive NK1R(-/-) mice with wild-type Salmonella showed improved median survival compared to naive NK1R(+/+) mice . Data from peritoneal macrophage infection studies suggest that this survival is in part contributed by increased IL-10 production . Oral vaccination with Salmonella CFA/I or Salmonella vector showed no significant differences in conferred protection against wild-type challenge for either NK1R(-/-) or NK1R(+/+) mice . Thus, these studies suggest that SP mediation contributes to proinflammatory responses to Salmonella infections.

Infect Immun, 2005 Jan, 73(1), 146 - 54
SipA, SopA, SopB, SopD, and SopE2 contribute to Salmonella enterica serotype typhimurium invasion of epithelial cells; Raffatellu M et al.; The centisome 63 type III secretion system (T3SS-1) encoded by Salmonella pathogenicity island 1 (SPI1) mediates invasion of epithelial cells by Salmonella enterica serotype Typhimurium . Characterization of mutants lacking individual genes has revealed that T3SS-1 secreted proteins (effectors) SopE2 and SopB are required for invasion while the SipA protein accelerates entry into cells . Here we have revisited the question of which T3SS-1 effectors contribute to the invasion of epithelial cells by complementing a strain lacking all of the effector genes that are required to cause diarrhea in a calf (a sipA sopABDE2 mutant) . Introduction of either the cloned sipA, the cloned sopB, or the cloned sopE2 gene increased the invasiveness of the sipA sopABDE2 mutant for nonpolarized HT-29 cells . However, a contribution of sopA or sopD to invasion was not apparent when invasion assays were performed with the nonpolarized colon carcinoma cell lines T84 and HT-29 . In contrast, introduction of either the sopA, the sopB, the sopD, or the sopE2 gene increased the invasiveness of the sipA sopABDE2 mutant for polarized T84 cells . Furthermore, introduction of a plasmid carrying sipA and sopB increased the invasiveness of the sipA sopABDE2 mutant for polarized T84 cells significantly compared to the introduction of plasmids carrying only sipA or sopB . We conclude that SipA, SopA, SopB, SopD, and SopE2 contribute to S . enterica serotype Typhimurium invasion of epithelial cells in vitro.

Infect Immun, 2005 Jan, 73(1), 88 - 102
Transcriptional adaptation of Shigella flexneri during infection of macrophages and epithelial cells: insights into the strategies of a cytosolic bacterial pathogen; Lucchini S et al.; Shigella flexneri, the etiologic agent of bacillary dysentery, invades epithelial cells as well as macrophages and dendritic cells and escapes into the cytosol soon after invasion . Dissection of the global gene expression profile of the bacterium in its intracellular niche is essential to fully understand the biology of Shigella infection . We have determined the complete gene expression profiles for S . flexneri infecting human epithelial HeLa cells and human macrophage-like U937 cells . Approximately one quarter of the S . flexneri genes showed significant transcriptional adaptation during infection; 929 and 1,060 genes were up- or down-regulated within HeLa cells and U937 cells, respectively . The key S . flexneri virulence genes, ipa-mxi-spa and icsA, were drastically down-regulated during intracellular growth . This theme seems to be common in bacterial infection, because the Ipa-Mxi-Spa-like type III secretion systems were also down-regulated during mammalian cell infection by Salmonella enterica serovar Typhimurium and Escherichia coli O157 . The bacteria experienced restricted levels of iron, magnesium, and phosphate in both host cell types, as shown by up-regulation of the sitABCD system, the mgtA gene, and genes of the phoBR regulon . Interestingly, ydeO and other acid-induced genes were up-regulated only in U937 cells and not in HeLa cells, suggesting that the cytosol of U937 cells is acidic . Comparison with the gene expression of intracellular Salmonella serovar Typhimurium, which resides within the Salmonella-containing vacuole, indicated that S . flexneri is exposed to oxidative stress in U937 cells . This work will facilitate functional studies of hundreds of novel intracellularly regulated genes that may be important for the survival and growth strategies of Shigella in the human host.

Int J Food Microbiol, 2005 Jan 15, 98(1), 35 - 51
A comparison of three modelling approaches for quantitative risk assessment using the case study of Salmonella spp . in poultry meat; Parsons DJ et al.; A comprehensive review of both the scientific literature and industry practices was undertaken to identify and quantify all sources of contamination throughout the entire poultry meat production chain by Salmonella spp . This information was used to develop a quantitative risk assessment (QRA) model for Salmonella in the production chain from the breeder farm to the chilled carcass . This was subsequently used as the basis on which to compare the merits of three approaches to QRA modelling in such systems . The original model used a Bayesian Network (BN) . The second method was a Markov chain Monte Carlo (MCMC) approach, a numerical Bayesian technique which retained a similar network structure but allowed further development, such as the separation of variability and uncertainty . The third method was a more detailed simulation model . The BN responds immediately to changes, such as entering evidence, because it does not use simulation and can propagate information from any point in the network to all others by Bayesian inference . However, it requires all the variables to be discrete, which introduces errors if continuous variables have to be discretized . These errors can accumulate . The MCMC approach does not require discrete variables while retaining some of the properties of the BN model, such as the ability to draw inferences from evidence . Finally, the simulation offers greater flexibility, such as consideration of the individual carcass, but may be more complex to implement as a result and sacrifices the ability to propagate evidence.

Cell Microbiol, 2005 Jan, 7(1), 147 - 55
Components of the peptidoglycan-recycling pathway modulate invasion and intracellular survival of Salmonella enterica serovar Typhimurium; Folkesson A et al.; Summary beta-Lactam resistance in enteric bacteria is frequently caused by mutations in ampD encoding a cytosolic N-acetylmuramyl- l-alanine amidase . Such mutants are blocked in murein (peptidoglycan) recycling and accumulate cytoplasmic muropeptides that interact with the transcriptional activator ampR, which de-represses beta-lactamase expression . Salmonella enterica serovar Typhimurium, an extensively studied enteric pathogen, was used to show that mutations in ampD decreased the ability of S . typhimurium to enter a macrophage derived cell line and made the bacteria more potent as inducers of inducible nitric oxide synthase (iNOS), as compared with the wild-type . ampG mutants, defective in the transport of recycled muropeptides across the cytoplasmic membrane, behaved essentially as the wild-type in invasion assays and in activation of iNOS . As ampD mutants also have reduced in vivo fitness in a murine model, we suggest that the cytoplasmic accumulation of muropeptides affects the virulence of the ampD mutants.

Cell Microbiol, 2005 Jan, 7(1), 105 - 13
The Salmonella SPI1 effector SopB stimulates nitric oxide production long after invasion; Drecktrah D et al.; Summary The ability of Salmonella enterica to invade and replicate within host cells depends on two type III secretion systems (TTSSs) encoded on pathogenicity islands 1 and 2 (SPI1 and SPI2) . The current paradigm holds that these systems translocate two classes of effectors that operate sequentially and independently . In essence, the SPI1 TTSS mediates early events (i.e . invasion) whereas the SPI2 TTSS mediates post-invasion processes (i.e . replication, vacuole maturation) . Contrary to this model, we have found in infected macrophages that a SPI1 effector, SopB/SigD, increased inducible nitric oxide synthase levels and nitric oxide production, host cell process previously known only to be a target of the SPI2 TTSS . Furthermore, SopB protein and message persist many hours after invasion . Our findings reveal an unanticipated potential for dialogue between the SPI1 and SPI2 TTSS and the host cell response.

Cell Microbiol, 2005 Jan, 7(1), 79 - 90
Derepression of Salmonella pathogenicity island 1 genes within macrophages leads to rapid apoptosis via caspase-1- and caspase-3-dependent pathways; Takaya A et al.; Summary Salmonella enterica serovar Typhimurium has been reported to induce apoptosis in infected macrophages within 14 h from the time of infection by a caspase-1-dependent mechanism . Here, we demonstrate that depletion of Lon protease in serovar Typhimurium induces rapid and massive apoptosis in macrophages by a mechanism involving both caspases-1 and -3 . This excessive induction of apoptosis was abrogated by disruption of invF, which is required for the expression of the Salmonella pathogenicity island 1 (SPI1) genes . Expression of hilA, a central regulator of SPI1 transcription, was repressed in the macrophages after phagocytosis, but this gene was continuously expressed when the DeltaLon mutant grew within the macrophages, so the SPI1 proteins accumulated . Thus, the increase in macrophage apoptosis induced by the DeltaLon mutant could result from continued expression of SPI1 genes under conditions where they are normally repressed . Once Salmonella has established a systemic infection, excess apoptosis of macrophages cells upon which the organism is reliant would be detrimental to the pathogen . Therefore, the Lon protease may be required to suppress apoptosis sufficiently to allow time for the bacterium to replicate, escape and invade new macrophages.

Gene Ther . 2004 Dec 23; {Epub ahead of print}
Salmonella-mediated oral DNA vaccination using stabilized eukaryotic expression plasmids; Bauer H et al.; The use of Salmonella for the delivery of plasmid-encoded heterologous antigens to eukaryotic host cells has proven successful in experimental systems, but its general applicability is still hampered by a severe instability of transformants carrying these expression plasmids . To overcome the problem of plasmid instability, new low copy number expression plasmids were constructed using different replicons . Comparative studies between transformants of the high copy number plasmid pCMVbeta and the different low copy number plasmids that contain the pMB1, p15A or pSC101 replicons on the pCMVbeta backbone, revealed a dramatic increase in plasmid stability both in vitro and in vivo . Analysis of the resulting immune responses against antigens encoded by these vectors indicated that the increased stability resulted in a strong and reproducible induction of both antigen-specific CD4(+) and CD8(+) T-cell and antibody responses even after a single application . In addition, protective immunity was induced against Listeria monocytogenes using listeriolysin as antigen, regardless of the copy number of the delivery plasmid employed . Finally, Salmonella expressing two independent antigens on compatible low copy number plasmids elicited robust responses to either antigen that is as effective as Salmonella transformed with each plasmid singly adding further versatility to this delivery system.Gene Therapy advance online publication, 23 December 2004; doi:10.1038/sj.gt.3302423.

Antimicrob Agents Chemother, 2005 Jan, 49(1), 289 - 301
Overexpression of the multidrug efflux operon acrEF by insertional activation with IS1 or IS10 elements in Salmonella enterica serovar typhimurium DT204 acrB mutants selected with fluoroquinolones; Olliver A et al.; High-level fluoroquinolone (FQ) resistance in Salmonella enterica serovar Typhimurium phage type DT204 has been previously shown to be essentially due to both multiple target gene mutations and active efflux by the AcrAB-TolC efflux system . In this study we show that in intermediatly resistant acrB-inactivated serovar Typhimurium DT204 mutants, high-level resistance to FQs can be restored on in vitro selection with FQs . In each FQ- resistant mutant selected from serovar Typhimurium DT204 acrB mutant strains, an insertion sequence (IS1 or IS10) was found integrated upstream of the acrEF operon, coding for AcrEF, an efflux pump highly homologous to AcrAB . In one of the strains, transposition of IS1 caused partial deletion of acrS, the putative local repressor gene of the acrEF operon . Sequence analysis showed that both IS1 and IS10 elements contain putative promoter sequences that might alter the expression of adjacent acrEF genes . Indeed, reverse transcription-PCR experiments showed an 8- to 10-fold increase in expression of acrF in these insertional mutants, relative to their respective parental strain, which correlated well with the resistance levels observed to FQs and other unrelated drugs . It is noteworthy that AcrEF did not contribute to the intrinsic drug resistance of serovar Typhimurium, since acrF deletion in wild-type strains did not result in any increase in drug susceptibility . Moreover, deletion of acrS did not cause any acrF overexpression or any decrease in drug susceptibility, suggesting that acrEF overexpression is mediated solely by the IS1 and IS10 promoter sequences and not by inactivity of AcrS . Southern blot experiments showed that the number of chromosomal IS1 and IS10 elements in the serovar Typhimurium DT204 genome was about 5 and 15 respectively . None were detected in epidemic serovar Typhimurium DT104 strains or in the serovar Typhimurium reference strain LT2 . Carrying IS1 and/or IS10 elements in their chromosome may thus be a selective advantage for serovar Typhimurium DT204 strains as opposed to DT104 strains for which no high-level FQ resistance nor insertional mutations were found . Taken together, the results of the present study indicate that the IS1- or IS10- activated AcrEF efflux pump may relay AcrAB in serovar Typhimurium, and underline the importance of transposable elements in the acquisition of FQ and multidrug resistance.

Crit Rev Food Sci Nutr, 2004, 44(6), 409 - 18
Calculating microbial survival parameters and predicting survival curves from non-isothermal inactivation data; Peleg M et al.; Irrespective of whether the isothermal semi-logarithmic survival curves of heat inactivated microbial cells or spores are linear or nonlinear, it is theoretically possible to numerically calculate their survival parameters from inactivation data obtained under non-isothermal conditions . A method to do the calculation, when the temperature history ('profile') is expressed algebraically, is demonstrated with simulated survival curves . It has been tested with the published survival data of Salmonella, whose nonlinear semi-logarithmic isothermal survival curves can be described by a power law model . The reported survival ratios of Salmonella, determined during non-isothermal heat treatments in a broth and in ground chicken breast, were used to estimate its isothermal survival parameters in the two media and their temperature dependence . These, in turn, were used to predict the cells' survival curves under different temperature 'profiles.' There was a good agreement between the predicted and the reported experimental survival curves in the broth case and reasonable agreement in the ground chicken breasts, where the database was considerably smaller The development of a mathematical method to calculate survival parameters from non-isothermal inactivation data will eliminate the need to determine these parameters under isothermal conditions, which can only be approximated and are technically difficult to perform . In many cases, the proposed method will also enable the determination of the survival parameters in the actual food or medium of interest, which may contain particles, or is too viscous to be heated and cooled effectively using the currently available experimental procedures . In principle, the described mathematical method can also be used to assess organisms' survival parameters in nonthermal inactivation processes, such as exposure to a dissipating chemical agent or the application of ultra high-pressure.

Vet Immunol Immunopathol, 1980 Aug, 1(3), 263 - 76
Visualization of immunosorption by scanning electron microscopy; Stucki M et al.; Immunosorption has become a very important biochemical and serological tool and it is the purpose of this paper to visualize this process qualitatively using the scanning electron microscope . Different carriers (i.e . CNBr activated cellulose and Sepharose, glutaraldehyde treated acrylamide-agarose beads Magnogel, and polystyrene cover slips) were coated with different antibodies and incubated with their homologous antigens such as pneumococci, ferritin, polymeric Salmonella flagellin and mechanically detached flagella, as well as tetanus toxoid, E . coli bacteriophage T4 and Rota virus particles . As negative controls the sorbents were incubated with heterologous antigens.

Poult Sci, 2004 Dec, 83(12), 2079 - 82
Recovery of Salmonellae from trisodium phosphate-treated commercially processed broiler carcasses after chilling and after seven-day storage; Bourassa DV et al.; Experiments were conducted to determine the effect of prechill trisodium phosphate (TSP) treatment on reducing salmonellae recovery from broiler carcasses immediately after chilling or following 7 d of storage . Carcasses were sampled for salmonellae using whole carcass enrichment for 24 h at 37 degrees C . In each of 7 trials, 40 carcasses were obtained from a commercial processing plant . Batches of 4 carcasses were subjected to a 5-s dip in 10% TSP (treatment) or not dipped (control) . Two carcasses from each batch were sampled immediately after chilling (d 0) and 2 carcasses were sampled after 7 d of storage . For trials 1 and 2, TSP treatment and control groups were chilled in separate chill tanks for 45 min . For trials 3 through 7, carcasses were rinsed with water and individually bagged with ice and water before chilling . For trials 1 and 2, 85% (17/20) of control carcasses were salmonellae-positive on d 0 compared with 45% (9/ 20) of the TSP-treated carcasses; after 7 d, 75% (15/20) of control carcasses were positive compared with 35% (7/ 20) for the TSP-treated carcasses . For trials 3 through 7, 46% (23/50) of control carcasses were salmonellae-positive on d 0 compared with 26% (13/50) of the TSP-treated carcasses; after 7 d, 20% (10/50) of control carcasses were positive compared with 4% (2/50) of the TSP-treated carcasses . TSP treatment resulted in significantly higher pH values for rinses . Salmonella recovery was decreased by refrigerated storage and treatment with TSP before immersion chilling.

J Agric Food Chem, 2004 Dec 29, 52(26), 8261 - 7
Essential oils of Satureja, Origanum, and Thymus species: chemical composition and antibacterial activities against foodborne pathogens; Chorianopoulos N et al.; The chemical composition of the essential oils obtained from the species restricted to Greece and the eastern Mediterranean region, Satureja spinosa L . and Thymus longicaulis L.; species endemic to central and south Greece, Satureja parnassica ssp . parnassica Heldr . and Sart ex Boiss.; species endemic to the island of Crete, Origanum dictamnus L.; and species widely distributed in the Mediterranean region, Satureja thymbra L . and Origanum vulgare L . subsp . hirtum, were determined by gas chromatography (GC) and GC/mass spectrometry (MS) analysis . The in vitro antibacterial activities of the essential oils were evaluated against a panel of five foodborne bacteria (Escherichia coli 0157:H7 NCTC 12900, Salmonella enteritidis PT4, Staphylococcus aureus ATCC 6538, Listeria monocytogenes ScottA, and Bacillus cereus FSS 134) . The analytical data indicated that various monoterpene hydrocarbons and phenolic monoterpenes constitute the major components of the oils, but their concentrations varied greatly among the oils examined . The antibacterial assay results showed that 5 muL doses of the essential oils extracted from the endemic Satureja species in Greece possess remarkable bactericidal properties, which are clearly superior as compared to those of Origanum and Thymus species essential oils . Therefore, they represent an inexpensive source of natural mixtures of antibacterial compounds that exhibit potentials for use in food systems to prevent the growth of foodborne bacteria and extend the shelf life of the processed food.

Microbiol Immunol, 2004, 48(12), 981 - 4
Isolation of Mini-Tn5Km2 Insertion Mutants of Salmonella enterica Serovar Oranienburg Sensitive to NaCl-Induced Osmotic Stress; Asakura H et al.; We previously reported that the viability of Salmonella Oranienburg strains under NaCl stress was variable and depended on the strain's origin; food strains were resistant and patient strains sensitive to NaCl . Therefore, we mutagenized a food strain with a mini-Tn5Km2 transposon . Of 2,400 mutants screened, 15 NaCl-sensitive mutants were isolated, and 7 genes associated with NaCl-sensitivity were identified . The intact genes complemented their own food-strain mutants, but not patient-strain mutants, suggesting that the difference in NaCl-sensitivity between food and patient S . Oranienburg strains might not arise from a single gene mutation, but from change in multiple osmoregulatory mechanisms in Salmonella.

Genetics, 2004 Dec, 168(4), 1787 - 94
Bile-Induced DNA Damage in Salmonella enterica; Prieto AI et al.; In the absence of DNA adenine methylase, growth of Salmonella enterica serovar Typhimurium is inhibited by bile . Mutations in any of the mutH, mutL, and mutS genes suppress bile sensitivity in a Dam(-) background, indicating that an active MutHLS system renders Dam(-) mutants bile sensitive . However, inactivation of the MutHLS system does not cause bile sensitivity . An analogy with Escherichia coli, in which the MutHLS system sensitizes Dam(-) mutants to DNA-injuring agents, suggested that bile might cause DNA damage . In support of this hypothesis, we show that bile induces the SOS response in S . enterica and increases the frequency of point mutations and chromosomal rearrangements . Mutations in mutH, mutL, or mutS cause partial relief of virulence attenuation in a Dam(-) background (50- to 100-fold by the oral route and 10-fold intraperitoneally), suggesting that an active MutHLS system reduces the ability of Salmonella Dam(-) mutants to cope with DNA-damaging agents (bile and others) encountered during the infection process . The DNA-damaging ability of bile under laboratory conditions raises the possibility that the phenomenon may be relevant in vivo, since high bile concentrations are found in the gallbladder, the niche for chronic Salmonella infections.

J Biol Chem . 2004 Dec 20; {Epub ahead of print}
Dissemination of lipid A deacylases (PagL) among gram-negative bacteria: Identification of active-site histidine and serine residues; Geurtsen J et al.; Lipopolysaccharide (LPS) is one of the main constituents of the Gram-negative bacterial outer membrane . It usually consists of a highly variable O-antigen, a less variable core oligosaccharide, and a highly conserved lipid moiety, designated lipid A . Several bacteria are capable of modifying their lipid A architecture in response to external stimuli . The outer-membrane localized lipid A 3-O-deacylase, encoded by the pagL gene of Salmonella enterica serovar Typhimurium, removes the fatty acyl chain from the 3 position of lipid A . Although a similar activity was reported in some other Gram-negative bacteria, the corresponding genes could not be identified . Here, we describe the presence of pagL homologs in a variety of Gram-negative bacteria . Although the overall sequence similarity is rather low, a conserved domain could be distinguished in the C-terminal region . The activity of the Pseudomonas aeruginosa and Bordetella bronchiseptica pagL homologs was confirmed upon expression in Escherichia coli, which resulted in the removal of a R-3-hydroxymyristoyl group from lipid A . Upon deacylation by PagL, E . coli lipid A underwent another modification, which was the result of the activity of the endogenous palmitoyl transferase PagP . Furthermore, we identified a conserved histidine-serine couple as active-site residues, suggesting a catalytic mechanism similar to serine hydrolases . The biological function of PagL remains unclear . However, since PagL homologs were found in both pathogenic and non-pathogenic species, PagL-mediated deacylation of lipid A probably does not have a dedicated role in pathogenicity.

Acta Pharm, 2004 Sep, 54(3), 243 - 50
Antimicrobial activity of grapefruit seed and pulp ethanolic extract; Cvetnic Z et al.; Antibacterial and antifungal activity of ethanolic extract of grapefruit (Citrus paradisi Macf., Rutaceae) seed and pulp was examined against 20 bacterial and 10 yeast strains . The level of antimicrobial effects was established using an in vitro agar assay and standard broth dilution susceptibility test . The contents of 3.92% of total polyphenols and 0.11% of flavonoids were determined spectrometrically in crude ethanolic extract . The presence of flavanones naringin and hesperidin in the extract was confirmed by TLC analysis . Ethanolic extract exibited the strongest antimicrobial effect against Salmonella enteritidis (MIC 2.06%, m/V) . Other tested bacteria and yeasts were sensitive to extract concentrations ranging from 4.13% to 16.50% (m/V).

J Infect Dis, 2005 Jan 15, 191(2), 312 - 7 Epub 2004 Dec 10.
Unique characteristics of the intestinal immune system as an inductive site after antigen reencounter; Kantele A et al.; Background . Immunization prepares the body for a reencounter with the microbe . Information on the targeting of immune effector cells during secondary immune response--that is, lymphocyte homing--is scarce . In the present study, the homing potentials of lymphocytes are examined after antigen reencounter at mucosal versus nonmucosal sites.Methods . Orally or parenterally immunized volunteers were reimmunized orally or parenterally with Salmonella typhi Ty21a, and the expression of the gut homing receptor (HR), alpha (4) beta (7), and of the peripheral lymph node HR, L-selectin, was investigated in circulating antigen-specific antibody-secreting cells (ASCs) . Lymphocytes were sorted by HR expression and examined for antibody production, by use of an enzyme-linked immunospot assay.Results . After oral reimmunization, 90% of ASCs were alpha (4) beta (7) positive and 88% were L-selectin positive, an expression profile that differed significantly from that found after oral primary immunization . After parenteral reimmunization, 45% of ASCs were alpha (4) beta (7) positive and 79% were L-selectin positive, similar to the results after parenteral primary immunization . The route of priming had no effect on HR patterns in either case.Conclusions . Homing potentials of lymphocytes depend on the site of antigen reencounter . Whereas the HR profile after parenteral reimmunization resembles that after primary immunization, the profile after oral reimmunization is uniquely characterized by high expression of both HRs, suggesting gut-localized memory and effective homing ability to both the mucosal and systemic immune system . These data may prove valuable in the search for the most effective immunization route in humans.

Ann Acad Med Singapore, 2004 Nov, 33(6), 749 - 53
A clinical audit of presentation and outcome of salmonella septicaemia; Habib AG; INTRODUCTION: Enteric fever is imported to developed countries while non-typhoidal salmonella infections occur globally . Clinicians and trainees need to recognise the varied presentations of serious salmonella infections . MATERIALS AND METHODS: We reviewed the clinical presentations, hospital course, complications and outcomes of 50 patients who were blood culture positive for Salmonella spp seen in 2 years . RESULTS: Nineteen of 24 patients with enteric fever had recently travelled to Asian countries . All the enteric fever patients recovered fully . Out of 26 patients with non-typhoidal salmonellosis, 10 had malignancies, 7 had immune dysfunction states and 3 had aortic aneurysms . Five patients had recurrent episodes of salmonellosis . Eight of these patients who had cancer (4), diabetes mellitus with renal failure (2) and gastric diseases (2) died . Fatal cases were older with multiple admissions and co-morbidities (median, 3) and presentation followed immunosuppressive interventions, often with no fever (4) . Onset was sudden with a short and fatally unresponsive course despite effective antimicrobial agents with microbiologic diagnosis made posthumously (4) . Death resulted rapidly from overwhelming sepsis and aneurysmal complications . Antibiotic resistance to ampicillin, cotrimoxazole and chloramphenicol was noted . CONCLUSION: Enteric fever should be considered in travellers returning from Asian countries with fever, and third-generation cephalosporins or quinolones should be used for empiric treatment . Given the presentation of non-typhoidal salmonella septicaemias, clinicians need to have a high index of suspicion and to consider preemptive therapy in patients with prior infection who are likely to develop severe immunosuppression following interventions.

FEMS Immunol Med Microbiol, 2005 Jan 1, 43(1), 81 - 9
In vitro activation of chicken leukocytes and in vivo protection against Salmonella enteritidis organ invasion and peritoneal S . enteritidis infection-induced mortality in neonatal chickens by immunostimulatory CpG oligodeoxynucleotide; He H et al.; Unmethylated CpG oligodinucleotides (CpG-ODN) flanked by specific bases found in bacterial DNA are known to stimulate innate immune responses . In this study, synthetic CpG-ODNs were evaluated for their in vitro stimulation of leukocyte and in vivo protection against Salmonella enteritidis (SE) in neonatal chickens . Our studies showed that CpG-ODN stimulated bactericidal activities, releasing granules (degranulation) and generating reactive oxygen species (oxidative burst), in chicken heterophils and up regulated nitric oxide production in chicken peripheral blood monocytes . When day-old chickens were given (i.p.) synthetic CpG-ODNs followed by oral challenge of SE, a significant reduction (p<0.05) of organ invasion by SE was observed in chickens pretreated with CpG-ODN containing the immunostimulatory GTCGTT motif . This CpG-OND also significantly reduced mortality of chickens with acute peritoneal infection of SE . Our study provides evidence that immunostimulatory CpG-ODN stimulated innate immune activities and enhanced the resistance to infectious pathogens in neonatal chickens.

J Vet Med B Infect Dis Vet Public Health, 2004 Dec, 51(10), 459 - 63
Impact of invA-PCR and Culture Detection Methods on Occurrence and Survival of Salmonella in the Flesh, Internal Organs and Lymphoid Tissues of Experimentally Infected Pigs; Arnold T et al.; Summary This study evaluated the suitability of invA gene amplification by PCR as an effective means of detecting Salmonella species in pigs experimentally infected with S . Typhimurium DT104 . A controlled infection study using 24 pigs was performed in order to compare efficacy, precision and detection rates of the invA-based PCR method originally described by Rahn, K . De Grandis, S.A., Clarke, R.C., McEwan, S.A., Galan, J.E., Ginocchio, C., Curtiss, R . 3rd, C.L . Gyles, (Mol . Cell . Probes 1992; 6: 271-279) as a new in-house invA-based PCR method for the specific detection of Salmonella spp . in pork and different tissue samples of slaughter pigs . Finally, PCR results were compared with culture detection rates obtained by isolation procedures following the ISO 6579:2000, the 'gold standard' . After slaughtering, 14 different tissue samples of each pig were investigated to verify the usefulness of the two invA-based PCR methods in different matrices of slaughter pigs . The results demonstrate that the application of the widely used invA-based primer pair (139 + 141) may result in questionable products if samples gained from selective enrichment in the Rappaport-Vassiliadis medium were investigated . These questionable products can lead to false-positive results, if no additional hybridization procedure is attached or if unspecialized persons use this method in routine laboratory practice . The newly developed in-house PCR method used is based on the 3'-prime region of invA, especially designed and harmonized for the detection of Salmonella in different matrices of slaughtered pigs after bacterial enriched broth culture . In this study, this PCR revealed no questionable products and, furthermore, the specificity of the amplificate could be tested by means of the restriction enzyme NdeI . In comparison with the culture detection procedure, the new PCR method has a sensitivity of 100% and a specificity of 96% . Thus, this method might be used as a meaningful tool in eliminating Salmonella-positive carcasses at slaughterhouse level and thus, keeping them out of the food chain.

Eur J Clin Microbiol Infect Dis, 2004 Oct, 23(10), 751 - 8
Nosocomial nontyphoidal salmonellosis after antineoplastic chemotherapy: reactivation of asymptomatic colonization?
Delaloye J, Merlani G, Petignat C, Wenger A, Zaman K, Monnerat C, Matzinger O, Beck Popovic M, Vuichard P, Ketterer N, Tarr PE.
An increased frequency of nontyphoidal salmonellosis is well established in cancer patients, but it is unclear whether this represents increased susceptibility to exogenous infection or opportunistic, endogenous reactivation of asymptomatic carriage . In a retrospective study, a simple case definition was used to identify the probable presence of reactivation salmonellosis in five cancer patients between 1996 and 2002 . Reactivation salmonellosis was defined as the development of nosocomial diarrhea >72 h after admission and following the administration of antineoplastic chemotherapy in an HIV-seronegative cancer patient who was asymptomatic on admission, in the absence of epidemiological evidence of a nosocomial outbreak . Primary salmonellosis associated with unrecognized nosocomial transmission or community acquisition and an unusually prolonged incubation period could not entirely be ruled out . During the same time period, another opportunistic infection, Pneumocystis pneumonia, was diagnosed in six cancer patients . Presumably, asymptomatic intestinal Salmonella colonization was converted to invasive infection by chemotherapy-associated intestinal mucosal damage and altered innate immune mechanisms . According to published guidelines, stool specimens from patients hospitalized for longer than 72 h should be rejected unless the patient is neutropenic or >or=65 years old with significant comorbidity . However, in this study neutropenia was present in only one patient, and four patients were <65 years old . Guidelines should thus be revised in order not to reject stool culture specimens from such patients . In cancer patients, nosocomial salmonellosis can occur as a chemotherapy-triggered opportunistic reactivation infection that may be similar in frequency to Pneumocystis pneumonia.

J Infect, 2005 Jan, 50(1), 1 - 5
Revised definition of 'fever of unknown origin': limitations and opportunities; Ergonul O et al.; AIM: The limitations and opportunities of revised definition of fevers of unknown origin (FUO) in comparison to conventional definition were investigated, and prehospital characteristics of the patients were detailed . METHOD: The patients were grouped according to both revised and classic definitions of FUO . RESULTS: Fifty-nine of the 80 patients (74%) met the conventional definition of FUO . Before their admissions, all patients had at least one course of antibiotic therapy . The aetiology was infectious in 52%, autoimmune in 19%, and neoplastic in 17% . In 12% of the cases, the reason for high fever could not be explained . The most common infectious aetiologies were various forms of tuberculosis (12%), brucellosis (12%), salmonella (7%) and malaria (5%) . The revised definition inflated the rate of infectious aetiology . CONCLUSION: A standardized set of diagnostic tools used in this study was suggested . The subjects of FUO series have to be screened for endemic infections.

J Bacteriol, 2005 Jan, 187(1), 400 - 3
Natural isolates of Salmonella enterica serovar Dublin carry a single nadA missense mutation; Bergthorsson U et al.; Nicotinic acid is required by most isolates of Salmonella enterica (serovar Dublin), a pathogen of cattle . A single nadA missense mutation causes the nutritional requirement of all serovar Dublin isolates tested . Models for persistence of this allele are tested and discussed.

J Bacteriol, 2005 Jan, 187(1), 238 - 48
Regulation of uptake and processing of the quorum-sensing autoinducer AI-2 in Escherichia coli; Xavier KB et al.; AI-2 is a quorum-sensing signaling molecule proposed to be involved in interspecies communication . In Escherichia coli and Salmonella enterica serovar Typhimurium, extracellular AI-2 accumulates in exponential phase, but the amount decreases drastically upon entry into stationary phase . In S . enterica serovar Typhimurium, the reduction in activity is due to import and processing of AI-2 by the Lsr transporter . We show that the Lsr transporter is functional in E . coli, and screening for mutants defective in AI-2 internalization revealed lsrK and glpD . Unlike the wild type, lsrK and glpD mutants do not activate transcription of the lsr operon in response to AI-2 . lsrK encodes the AI-2 kinase, and the lsrK mutant fails to activate lsr expression because it cannot produce phospho-AI-2, which is the lsr operon inducer . glpD encodes the glycerol-3-phosphate (G3P) dehydrogenase, which is involved in glycerol and G3P metabolism . G3P accumulates in the glpD mutant and represses lsr transcription by preventing cyclic AMP (cAMP)-catabolite activator protein (CAP)-dependent activation . Dihydroxyacetone phosphate (DHAP) also accumulates in the glpD mutant, and DHAP represses lsr transcription by a cAMP-CAP-independent mechanism involving LsrR, the lsr operon repressor . The requirement for cAMP-CAP in lsr activation explains why AI-2 persists in culture fluids of bacteria grown in media containing sugars that cause catabolite repression . These findings show that, depending on the prevailing growth conditions, the amount of time that the AI-2 signal is present and, in turn, the time that a given community of bacteria remains exposed to this signal can vary greatly.

J Leukoc Biol . 2004 Dec 15; {Epub ahead of print}
Slc11a1-mediated resistance to Salmonella enterica serovar Typhimurium and Leishmania donovani infections does not require functional inducible nitric oxide synthase or phagocyte oxidase activity; White JK et al.; Solute carrier family 11a member 1 (Slc11a1; formerly natural resistance-associated macrophage protein 1) encodes a late endosomal/lysosomal protein/divalent cation transporter, which regulates iron homeostasis in macrophages . During macrophage activation, Slc11a1 exerts pleiotropic effects on gene regulation and function, including generation of nitric oxide (NO) via inducible NO synthase (iNOS; encoded by Nos2A) and of reactive oxygen intermediates (ROI) via the phagocyte oxidase complex . As NO and ROI have potent antimicrobial activity in macrophages, it was assumed that their activities would contribute to Slc11a1-regulated innate resistance to Salmonella enterica serovar Typhimurium and Leishmania donovani . By intercrossing mice with gene disruptions at Nos2A and Cybb (encoding gp91phox, the heavy chain subunit of cytochrome b-245 and an essential component of phagocyte reduced nicotinamide adenine dinucleotide phosphate oxidase) onto equivalent Slc11a1 wild-type and mutant genetic backgrounds, we demonstrate that neither iNOS nor gp91phox activity is required for Slc11a1-mediated innate resistance to either infection . Functional gp91phox and iNOS are required to control S . enterica serovar Typhimurium in non-Slc11a1-regulated phases of infection . For L . donovani, an organ-specific requirement for iNOS to clear parasites from the spleen was observed at 50 days post-infection, but neither iNOS nor gp91phox influenced late-phase infection in the liver . This contrasted with Leishmania major infection, which caused rapid lesion growth and death in iNOS knockout mice and some exacerbation of disease with gp91phox deficiency . This highlights the adaptive differences in tissue and cellular tropisms between L . donovani and L . major and the different genes and mechanisms that regulate visceral versus cutaneous forms of the disease.

Altern Lab Anim, 2003 Sep, 31(4), 393 - 9
SAR modelling of complex phenomena: probing methodological limitations; Rosenkranz HS; The increased acceptance of the use of structure-activity relationship (SAR) approaches to toxicity modelling has necessitated an evaluation of the limitations of the methodology . In this study, the limit of the capacity of the MULTICASE SAR program to model complex biological and toxicological phenomena was assessed . It was estimated that, provided the data set consists of at least 300 chemicals, divided equally between active and inactive compounds, the program is capable of handling phenomena that are even more "complex" than those modelled up to now (for example, allergic contact dermatitis, Salmonella mutagenicity, biodegradability, inhibition of tubulin polymerisation) . However, within the data sets currently used to generate SAR models, there are limits to the complexity that can be handled . This may be the situation with regard to the modelling of systemic toxicity (for example, the LD50).

Z Kardiol, 2004 Dec, 93(12), 964 - 967
A mycotic aneurysm of the ascending aorta and aortic arch induced by salmonella enteritidis; Schneider S et al.; In very rare cases, salmonella infection may be associated with extra-intestinal manifestations . Of these, a mycotic aneurysm represents a life-threatening complication that is characterised by a high mortality rate . Prompt treatment with a combination of antibiotic therapy and surgical intervention is urgently required . We report on the case of a 60-year-old woman who presented with salmonella bacteraemia and the rare complication of an infected aneurysm of the ascending aorta and aortic arch.

Am J Med Sci, 2004 Dec, 328(6), 315 - 8
Risk factors for recurrent bacteremia in adult patients with nontyphoid salmonellosis; Hsu RB et al.; BACKGROUND: This study sought to find the risk factors for recurrent bacteremia in adult patients with nontyphoid salmonellosis . METHOD: Retrospective chart review . RESULT: Between September 1984 and December 2003, 235 adult (age > or = 18 years old) patients with bacteremia with nontyphoid salmonellosis were admitted to our hospital . Among them, 130 patients (55%) had immunodeficiency, 31 patients (13%) had systemic lupus erythematosus, 26 patients (11%) had hematologic malignancies, 50 patients (21%) had solid organ cancers, and 39 patients (17%) had endovascular infections . Thirty-seven patients had recurrent bacteremia during the study period . Both univariate and multivariate analysis showed that immunodeficiency was the only predictor of recurrent bacteremia (odds ratio, 2.79; P = 0.013) . The overall hospital mortality rate was 26%: 8% for patients with recurrent bacteremia and 29% for patients without recurrence . The independent risk factors of hospital death were old age, not recurrent infection, and solid organ cancers . CONCLUSION: Old age, systemic lupus erythematosus, malignancies, and immunodeficiency were common in adult patients with nontyphoid Salmonella bacteremia . The incidence of recurrent bacteremia was 16% . Immunodeficiency predisposed patients to recurrent bacteremia . Recurrent bacteremia was associated with a lower hospital mortality rate, however.

Proc Natl Acad Sci U S A . 2004 Dec 14; {Epub ahead of print}
In vitro characterization of IroB, a pathogen-associated C-glycosyltransferase; Fischbach MA et al.; Pathogenic strains of Escherichia coli and Salmonella enterica modify the tricatecholic siderophore enterobactin (Ent) by glucosylation of three aryl carbon atoms, a process controlled by the iroA locus {Hantke, K., Nicholson, G., Rabsch, W . & Winkelmann, G . (2003) Proc . Natl . Acad . Sci . USA 100, 3677-3682} . Here, we report the purification of the IroB protein and its characterization as the Ent C-glucosyltransferase . IroB transfers glucosyl groups from uridine-5'-diphosphoglucose to C5 of one, two, or three of the 2,3-dihydroxybenzoyl units of Ent to yield monoglucosyl-C-Ent (MGE), diglucosyl-C-Ent (DGE), and triglucosyl-C-Ent (TGE) . DGE, also known as salmochelin S4, and macrolactone-opened derivatives have been isolated from the culture broths of S . enterica and uropathogenic E . coli {Bister, B., Bischoff, D., Nicholson, G . J., Valdebenito, M., Schneider, K., Winkelmann, G., Hantke, K . & Sussmuth, R . D . (2004) Biometals 17, 471-481}, but MGE and TGE have not been reported previously . IroB has a kcat of approximately 10 min(-1) for the first C-glucosylation and is distributive, with sequential conversion and buildup of MGE and then DGE . The C5 to C1' regioselectivity of the 2,3-dihydroxybenzoyl-glucose linkage at all three rings of TGE suggests a C5 carbanion, para to the C2 phenolate oxygen, as the carbon nucleophile in this novel enzymatic C-glucosylation.

Acta Clin Belg, 2004 Jul-Aug, 59(4), 232 - 4
Salmonella enterica subspecies houtenae serotype 44:z4, z23:--as a rare cause of meningitis; Wybo I et al.; Reptiles can carry and shed the bacterium Salmonella without showing any signs of illness . Transmission occurs by ingesting Salmonella after handling a reptile or objects contaminated by a reptile . Young children are especially vulnerable to Salmonella infection and can experience serious complications . We describe a case of reptile-associated Salmonella meningitis in a 2.5-month-old infant.

Heart Lung, 2004 Nov-Dec, 33(6), 414 - 6
Salmonella paratyphi A enteric fever mimicking viral meningitis; Kudalkar D et al.; Enteric fevers are caused by invasive strains of Salmonella . Classic enteric fever is caused by S . typhi and usually less severe enteric fevers are caused by S . paratyphi A, B, or C . We present a case of S . paratyphi A enteric fever aseptic meningitis . Headache was so prominent in the case presented that a lumbar puncture was performed to rule out meningitis . Rose spots were not apparent in this dark-skinned patient . Our patient did not have increased serum transaminases and did not have leukopenia, which are common findings in enteric fever . The absence of these findings and the relative bradycardia may be explained by the antimicrobial therapy the patient received before admission . After ruling out malaria, clinicians should suspect enteric fever in patients recently returning from endemic areas, in patients presenting with acute fevers without localizing signs.

Int J Med Microbiol, 2004 Oct, 294(6), 395 - 9
Flagella-mediated bacterial motility accelerates but is not required for Salmonella serotype Enteritidis invasion of differentiated Caco-2 cells; van Asten FJ et al.; The relative contributions of the flagellum and the flagella-associated bacterial motility in the invasion of Caco-2 cells by Salmonella serotype Enteritidis were investigated using an fliC mutant defective in flagellin production and a motA mutant that carries flagella but is non-motile . Infection assays demonstrated that, at 1 h of infection, both the fliC and the motA mutants were severely impaired in bacterial invasion compared to the parental strain . Infection assays at 3 h infection demonstrated virtually equal invasion levels for both non-motile mutants and the parental strain . Together these data suggest that flagella-mediated bacterial motility accelerates the invasion of Salmonella but is not required for the invasion event per se.

Int J Med Microbiol, 2004 Oct, 294(6), 363 - 71
Use of the alpha-hemolysin secretion system of Escherichia coli for antigen delivery in the Salmonella typhi Ty21a vaccine strain; Gentschev I et al.; This study examined the suitability of the hemolysin secretion system of Escherichia coli for expression and delivery of alpha-hemolysin (HlyA) by the S . typhi Ty21a strain, the only live oral Salmonella vaccine strain licensed for human use, under in vitro and in vivo conditions . For this purpose, two plasmid vectors encoding either the whole alpha-hemolysin of E . coli (pANN202-812/pMOhly2) or the hemolysin secretion signal (pMOhly1) were transferred into S . typhi Ty21a . S . typhi Ty21a carrying pANN202-812/pMOhly2 revealed efficient secretion of hemolysin in vitro . After formulation according to a process suitable for commercial production of Salmonella-based live bacterial vaccines, plasmids were shown to be stable in Ty21a and hemolysin secretion was demonstrated even after storage of the strains under real-time and stress conditions . After intranasal immunization of mice with S . typhi Ty21a/pANN202-812 plasmids are stable in vivo, and immunization induced a profound immune response against the heterologous HlyA antigen . Therefore, the combination of the hemolysin secretion system and S . typhi Ty21a could form the basis for a new generation of live bacterial vaccines.

MMWR Morb Mortal Wkly Rep, 2004 Dec 10, 53(48), 1132 - 4
Salmonella serotype Typhimurium outbreak associated with commercially processed egg salad--Oregon, 2003; Centers for Disease Control and Prevention (CDC); On September 24, 2003, Oregon epidemiologists noted an increase in Salmonella enterica serotype Typhimurium isolates tested during September at the Oregon State Public Health Laboratories . Of 16 isolates, six had matching pulsed-field gel electrophoresis (PFGE) patterns . The laboratory findings prompted an investigation by Oregon Health Services and CDC that identified 18 cases of infection with S . Typhimurium linked to kits for making egg salad that were distributed by a vendor to a supermarket chain . The Food and Drug Administration (FDA) conducted an environmental investigation but was unable to determine the mechanism of contamination . This was the first reported S . Typhimurium outbreak associated with a commercially processed, widely distributed, hard-boiled egg product . Epidemiologists and other public health staff should continue to investigate apparent clusters of salmonellosis and be aware that even commercially processed egg products can be a source of Salmonella.

Eur Surg Res, 2004 Nov-Dec, 36(6), 331 - 7
Attenuation of leukocyte sequestration by selective blockade of PECAM-1 or VCAM-1 in murine endotoxemia; Nolte D et al.; BACKGROUND: Molecular mechanisms regulating leukocyte sequestration into the tissue during endotoxemia and/or sepsis are still poorly understood . This in vivo study investigates the biological role of murine PECAM-1 and VCAM-1 for leukocyte sequestration into the lung, liver and striated skin muscle . METHODS: Male BALB/c mice were injected intravenously with murine PECAM-1 IgG chimera or monoclonal antibody (mAb) to VCAM-1 (3 mg/kg body weight); controls received equivalent doses of IgG2a (n = 6 per group) . Fifteen minutes thereafter, 2 mg/kg body weight of Salmonella abortus equi endotoxin was injected intravenously . At 24 h after the endotoxin challenge, lungs, livers and striated muscle of skin were analyzed for their myeloperoxidase activity . To monitor intravital leukocyte-endothelial cell interactions, fluorescence videomicroscopy was performed in the skin fold chamber model of the BALB/c mouse at 3, 8 and 24 h after injection of endotoxin . RESULTS: Myeloperoxidase activity at 24 h after the endotoxin challenge in lungs (12,171 +/- 2,357 mU/g tissue), livers (2,204 +/- 238 mU/g) and striated muscle of the skin (1,161 +/- 110 mU/g) was significantly reduced in both treatment groups as compared to controls, with strongest attenuation in the PECAM-1 IgG treatment group . Arteriolar leukocyte sticking at 3 h after endotoxin (230 +/- 46 cells x mm(-2)) was significantly reduced in both treatment groups . Leukocyte sticking in postcapillary venules at 8 h after endotoxin (343 +/- 69 cells/mm2) was found reduced only in the VCAM-1-mAb-treated animals (215 +/- 53 cells/mm2), while it was enhanced in animals treated with PECAM-1 IgG (572 +/- 126 cells/mm2) . CONCLUSION: These data show that both PECAM-1 and VCAM-1 are involved in endotoxin-induced leukocyte sequestration in the lung, liver and muscle, presumably through interference with arteriolar and/or venular leukocyte sticking . 2004 S . Karger AG, Basel.

Euro Surveill . 2004 Nov 01;9(11) {Epub ahead of print}
Dramatic shift in the epidemiology of Salmonella enterica serotype Enteritidis phage types in western Europe, 1998-2003 - results from the Enter-net international salmonella database; Fisher IS; Salmonella enterica serotype Enteritidis is the predominant salmonella serovar identified by the Enter-net national reference laboratories in western Europe . As it is the most commonly recognised serotype, it is important that phage typing is carried out so that outbreaks can be recognised and confirmed, and trends in infections identifed . Data from the Enter-net salmonella database show that there has been a dramatic shift between phage types identified in Europe from 1998-2003 . In 1998, the proportion of phage type (PT) 4 was 61.8%, making it the most frequently identified phage type in humans (21 630 cases), whereas by 2003 the proportion of PT4 had fallen to 32.1% (8794 cases) with other strains increasing, both in proportion and numbers . This paper identifies the emerging strains that are becoming more relevant in public health terms.

Euro Surveill . 2004 Nov 01;9(11) {Epub ahead of print}
International trends in salmonella serotypes 1998-2003 - a surveillance report from the Enter-net international surveillance network; Fisher IS; One of the objectives of any surveillance activity is to monitor trends in infections . The international surveillance network for human enteric infections, Enter-net, has been collecting and reporting data on laboratory-confirmed human salmonella infections since 1993 . The number of cases identified rose in the mid-1990s, with the peak being in 1997 . This paper describes the subsequent decline in salmonella serotypes being reported by the national reference laboratories participating in the Enter-net surveillance network between 1998-2003 . The total number of human cases of salmonellosis reported by the Enter-net participating countries has fallen from 220 698 to 142 891 during this period . Even at these reported levels salmonellosis remains a major cause of morbidity in humans.

J Med Microbiol, 2005 Jan, 54(Pt 1), 51 - 4
Rapid detection of food-borne pathogens by using molecular techniques; Naravaneni R et al.; Traditional methods of identification of food-borne pathogens, which cause disease in humans, are time-consuming and laborious, so there is a need for the development of innovative methods for the rapid identification of food-borne pathogens . Recent advances in molecular cloning and recombinant DNA techniques have revolutionized the detection of pathogens in foods . In this study the development of a PCR-based technique for the rapid identification of the food-borne pathogens Salmonella and Escherichia coli was undertaken . Suitable primers were designed based on specific gene fimA of Salmonella and gene afa of pathogenic E . coli for amplification . Agarose gel electrophoresis and subsequent staining with ethidium bromide were used for the identification of PCR products . The size of the amplified product was 120 bp as shown by comparison with marker DNA . These studies have established that fimA and afa primers were specific for detecting Salmonella and pathogenic E . coli, respectively, in the environmental samples . Thus a rapid, sensitive and reliable technique for the detection of Salmonella and pathogenic E . coli was developed.

J Biol Chem . 2004 Dec 27; {Epub ahead of print}
Bacteriophage P22 tail accessory factor gp26 is a long triple-stranded coiled-coil; Andrews D et al.; P22 is a well-characterized tailed bacteriophage that infects Salmonella enterica serovar Typhimurium . It is characterized by a "short" tail, which is formed by five proteins: the dodecameric portal protein (gp1), three tail accessory factors (gp4, gp10, gp26), and six trimeric copies of the tail-spike protein (gp9) . We have isolated the gene encoding tail accessory factor gp26, which is responsible for stabilization of viral DNA within the mature phage, and using a variety of biochemical and biophysical techniques we show that gp26 is very likely a triple stranded coiled-coil protein . Electron microscopic examination of purified gp26 indicates that the protein adopts a rod-like structure approximately 210&amp;#197; in length . This trimeric rod displays an exceedingly high intrinsic thermostability (Tm ~85&amp;#176;C), which suggests a potentially important structural role within the phage tail apparatus . We propose that gp26 forms the thin needle-like fiber emanating from the base of the P22 neck that has been observed by electron microscopy of negatively stained P22 virions . By analogy with viral trimeric coiled-coil class I membrane fusion proteins, gp26 may represent the membrane-penetrating device used by the phage to pierce the host outer membrane.

J Microbiol Methods, 2005 Feb, 60(2), 169 - 77
Allele-specific PCR method based on rfbS sequence for distinguishing Salmonella gallinarum from Salmonella pullorum: serotype-specific rfbS sequence polymorphism; Shah DH et al.; Cloning and sequence analysis of rfbS gene identified two polymorphic nucleotides, one at position 598 (Salmonella gallinarum-specific) and other at position 237 (Salmonella pullorum-specific) . Based on S . gallinarum-specific nucleotide found at position 598, an allele-specific PCR method was developed for serotype-specific detection of S . gallinarum . This PCR method was able to discriminate pure cultures of S . gallinarum from S . pullorum and other Salmonella serotypes from serogroup D in less than 3 h . Serotype-specific detection of S . gallinarum was possible in less than 24 h when the PCR was applied on the presumptive Salmonella colonies obtained after overnight incubation of selective media plates streaked with the clinical material from diseased chickens . As little as 100 pg of genomic DNA could be detected with S . gallinarum-specific primers; no PCR product was detected in non-S . gallinarum serotypes of serogroup D and other closely related non-salmonella organisms . This rfbS allele-specific amplification assay is specific, reproducible and less time consuming than the standard bacteriological methods used to detect S . gallinarum and could be an effective molecular tool for rapid definitive diagnosis of fowl typhoid in the areas of endemicity where fowl typhoid infection exists.

J Ethnopharmacol, 2005 Jan 4, 96(1-2), 107 - 12
Chemical composition, antibacterial and antifungal activities of the essential oil of Haplophyllum tuberculatum from Oman; Al-Burtamani SK et al.; The chemical composition of the essential oil of Haplophyllum tuberculatum (Forsskal) A . Juss (Rutaceae) was analyzed by gas chromatography-mass spectral (GC-MS) and 13C NMR spectroscopy . Thirty compounds, constituting about 99.7% of the total oil, were identified . The most abundant oil components are beta-phellandrene (23.3%), limonene (12.6%), (Z)-beta-ocimene (12.3%), beta-caryophyllene (11.6%), myrcene (11.3%), and alpha-phellandrene (10.9%) . Ten microlitres (25 mg) of pure oil partially inhibited the growth of Escherichia coli, Salmonella choleraesuis, and Bacillus subtilis to the same extent as 0.10 microg of gentamycin sulfate . The oil also affected the mycelial growth of Curvularia lunata and Fusarium oxysporium in a dose-dependent manner but had no effect on the germination of their spores.

Indian J Exp Biol, 2004 Nov, 42(11), 1100 - 6
Pathogenic effects of Salmonella enterica subspecies enterica serovar Typhimurium on sprouting and growth of maize; Singh BR et al.; The study was undertaken to understand effects and survival of S . enterica subspecies enterica serovar Typhimurium (S . Typhimurium), a zoonotic serovar, on maize seed germination and plant growth . All the four strains of S . enterica subspecies enterica serovar Typhimurium significantly reduced germination of maize seeds in sprouting plates as well as in soil . About > or =2.7x10(3) Salmonella cfu ml(-1) of soaking water, while > or =2.7x10(7) Salmonella cfu g(-1) soil were required to significantly inhibit germination of maize . Similar inhibition of germination could be observed using > or = 16 mg of bacteria free Salmonella cell lysate (CL) protein per g of soil or > or =0.5 mg of CL protein per ml of soaking water in sprouting plates . At the constant dose of 3.6x10(7) to 3.8x10(7) Salmonella cfu or 5 mg cell lysate protein ml(-1) of soaking water, four strains of Salmonella significantly reduced germination, however difference between strains was insignificant . After germination too, maize growth was affected both by Salmonella organism and CL with little strain-to-strain variation . All Salmonella persisted in growing plants from 15 to 35 days of plant age and up to 190 days in soil . Maize plants once grown for a week in sterile soil were resistant to invasion of S . enterica subspecies enterica serovar Typhimurium in their leaves even in doses as high as 7.6x10(9) cfu g(-1) of soil . Salmonella persisted better and longer in plants grown from contaminated seed sown in loam soil, but rarely in plants grew in sandy soil . All maize plants had Salmonella in their stumps even after 35 days of sowing irrespective of kind of soil, primary source of infection (soil or seed) and type of S . enterica subspecies enterica serovar Typhimurium strain . The study revealed that Salmonella is not only zoonotic but a phytopathogen also.

Clin Pediatr (Phila), 2004 Nov-Dec, 43(9), 825 - 9
Risk factors for development of nontyphoid Salmonella bacteremia; Grisaru-Soen G et al.; The objective of this paper was to identify risk factors for nontyphoid Salmonella bacteremia by making a retrospective chart review of 39 patients with nontyphoid Salmonella bacteremia . The control group included 30 patients with positive Salmonella stool culture (gastroenteritis group) . Demographic factors, presenting signs and symptoms, antimicrobial treatment before admission, and microbiologic results were recorded . Nine patients (23%) were excluded owing to recognized risk factors for development of extraintestinal disease . Seventeen cases (57%) occurred during summer time, whereas the gastroenteritis group had a less seasonal tendency . Eighty percent of the patients with Salmonella bacteremia had a previous history of diarrhea . At admission more patients in the bacteremia group were febrile and had leukocytosis (73% vs 33% and 37% vs 20%, respectively) . More patients in the bacteremia group had previous antibiotic treatment (57% vs 20%, p<0.01) . The Salmonella types were mainly C and D in the bacteremia group (40% each), and B and C in the gastroenteritis group (26% and 52%, respectively) . The risk factors for Salmonella bacteremia in previously healthy children include warm season, previous gastrointestinal illness, and preexposure to antibiotics.

J Clin Microbiol, 2004 Dec, 42(12), 5767 - 73
Emergence of extended-spectrum-beta-lactamase (CTX-M-9)-producing multiresistant strains of Salmonella enterica serotype Virchow in poultry and humans in France; Weill FX et al.; During 2002 to 2003, eight Salmonella enterica serotype Virchow poultry and poultry product isolates from various sources (chicken farms, poultry slaughterhouse, or retail store) and one S . enterica rough strain isolated from human feces were found to produce extended-spectrum beta-lactamase CTX-M-9 . Poultry and poultry product isolates were recovered from different locations in the southwest of France . The human rough isolate had sequences of flagellin genes (fliC and fljB) typical of serotype Virchow and ribotyping and pulsed-field gel electrophoresis (PFGE) patterns closely similar to those of serotype Virchow strains . PFGE confirmed the clonal relationship between the poultry isolates, while the human isolate displayed a pattern with 94% homology . The bla(CTX-M-9) gene was located on a conjugative plasmid and was shown to be linked to orf513 . Plasmid profiling found a very similar EcoRI restriction pattern in six transconjugants studied, including transconjugants obtained from the human isolate . A single hatchery, supplying chicks to the six farms, was identified . Emergence of extended-spectrum beta-lactamase-producing S . enterica strains in food animals is a major concern, as such strains could disseminate on a large scale and lead to antibiotic therapy difficulties.

J Clin Microbiol, 2004 Dec, 42(12), 5722 - 30
Variable number of tandem repeats in Salmonella enterica subsp . enterica for typing purposes; Ramisse V et al.; The genomic sequences of Salmonella enterica subsp . enterica strains CT18, Ty2 (serovar Typhi), and LT2 (serovar Typhimurium) were analyzed for potential variable number tandem repeats (VNTRs) . A multiple-locus VNTR analysis (MLVA) of 99 strains of S . enterica supsp . enterica based on 10 VNTRs distinguished 52 genotypes and placed them into four groups . All strains tested were independent human isolates from France and did not reflect isolates from outbreak episodes . Of these 10 VNTRs, 7 showed variability within serovar Typhi, whereas 1 showed variability within serovar Typhimurium . Four VNTRs showed high Nei's diversity indices (DIs) of 0.81 to 0.87 within serovar Typhi (n = 27) . Additionally, three of these more variable VNTRs showed DIs of 0.18 to 0.58 within serovar Paratyphi A (n = 10) . The VNTR polymorphic site within multidrug-resistant (MDR) serovar Typhimurium isolates (n = 39; resistance to ampicillin, chloramphenicol, spectinomycin, sulfonamides, and tetracycline) showed a DI of 0.81 . Cluster analysis not only identified three genetically distinct groups consistent with the present serovar classification of salmonellae (serovars Typhi, Paratyphi A, and Typhimurium) but also discriminated 25 subtypes (93%) within serovar Typhi isolates . The analysis discriminated only eight subtypes within serovar Typhimurium isolates resistant to ampicillin, chloramphenicol, spectinomycin, sulfonamides, and tetracycline, possibly reflecting the emergence in the mid-1990s of the DT104 phage type, which often displays such an MDR spectrum . Coupled with the ongoing improvements in automated procedures offered by capillary electrophoresis, use of these markers is proposed in further investigations of the potential of MLVA in outbreaks of salmonellosis, especially outbreaks of typhoid fever.

Microbiology, 2004 Dec, 150(Pt 12), 4095 - 105
Wzx proteins involved in biosynthesis of O antigen function in association with the first sugar of the O-specific lipopolysaccharide subunit; Marolda CL et al.; One of the most common pathways for the export of O-specific lipopolysaccharide (LPS) across the plasma membrane requires the participation of the Wzx protein . Wzx belongs to a family of integral membrane proteins that share little conservation in their primary amino acid sequence, making it difficult to delineate functional domains . This paper reports the cloning and expression in Escherichia coli K-12 of various Wzx homologues from different bacteria as FLAG epitope-tagged protein fusions . A reconstitution system for O16 LPS synthesis was used to assess the ability of each Wzx protein to complement an E . coli K-12 Deltawzx mutant . The results demonstrate that Wzx proteins from O-antigen systems that use N-acetylglucosamine or N-acetylgalactosamine for the initiation of the biosynthesis of the O repeat can fully complement the formation of O16 LPS . Partial complementation was seen with Wzx from Pseudomonas aeruginosa, a system that uses N-acetylfucosamine in the initiation reaction . In contrast, there was negligible complementation with the Wzx protein from Salmonella enterica, a system in which galactose is the initiating sugar . These results support a model whereby the first sugar of the O repeat can be recognized by the O-antigen translocation machinery.

Microbiology, 2004 Dec, 150(Pt 12), 3947 - 57
The pmrF polymyxin-resistance operon of Yersinia pseudotuberculosis is upregulated by the PhoP-PhoQ two-component system but not by PmrA-PmrB, and is not required for virulence; Marceau M et al.; The Yersinia pseudotuberculosis chromosome contains a seven-gene polycistronic unit (the pmrF operon) whose products share extensive homologies with their pmrF counterparts in Salmonella enterica serovar Typhimurium (S . typhimurium), another Gram-negative bacterial enteropathogen . This gene cluster is essential for addition of 4-aminoarabinose to the lipid moiety of LPS, as demonstrated by MALDI-TOF mass spectrometry of lipid A from both wild-type and pmrF-mutated strains . As in S . typhimurium, 4-aminoarabinose substitution of lipid A contributes to in vitro resistance of Y . pseudotuberculosis to the antimicrobial peptide polymyxin B . Whereas pmrF expression in S . typhimurium is mediated by both the PhoP-PhoQ and PmrA-PmrB two-component regulatory systems, it appears to be PmrA-PmrB-independent in Y . pseudotuberculosis, with the response regulator PhoP interacting directly with the pmrF operon promoter region . This result reveals that the ubiquitous PmrA-PmrB regulatory system controls different regulons in distinct bacterial species . In addition, pmrF inactivation in Y . pseudotuberculosis has no effect on bacterial virulence in the mouse, again in contrast to the situation in S . typhimurium . The marked differences in pmrF operon regulation in these two phylogenetically close bacterial species may be related to their dissimilar lifestyles.

Int J Food Microbiol, 2005 Jan 1, 97(3), 327 - 39
Metabiotic associations of molds and Salmonella Poona on intact and wounded cantaloupe rind; Richards GM et al.; Salmonella Poona, a serotype rarely implicated in human infections, has recently caused several cantaloupe-associated outbreaks of salmonellosis . Metabiotic associations of molds and foodborne pathogens on produce have been reported . We tested proteolytic activity and measured changes in the pH of cantaloupe rind caused by growth of Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Geotrichum candidum, and Penicillium expansum . Survival and growth characteristics of Salmonella Poona co-infected with each mold on the surface rind and in wounded rind tissue as affected by temperature were determined . C . cladosporioides, G . candidum, and P . expansum, but not A . alternata and E . nigrum, showed proteolytic activity on agar media containing gelatin and/or casein, with concurrent increases in pH, thus favoring survival and growth of salmonellae . Intact and mechanically wounded tissue of cantaloupe rinds were inoculated with a five-strain mixture of S . Poona and/or test mold . Five inoculation schemes were used: mold only, S . Poona only, mold and S . Poona simultaneously, mold then S . Poona 3 days later, and S . Poona then mold 3 days later . The pH of cantaloupe rinds inoculated with molds and stored at 20 degrees C for 14 days was significantly higher (P<==0.05) than on day 0 . Only the pH of rinds inoculated with C . cladosporioides or G . candidum was significantly higher (P<==0.05) on day 21 than on day 0, when cantaloupes were stored at 4 degrees C . An initial population of S . Poona increased from 3.3 log(10) cfu/sample (ca . 7 cm(2)) of cantaloupe rind to populations as high as 9.5 log(10) cfu/sample during storage at 20 degrees C for up 14 days, regardless of co-inoculation with molds . Populations of S . Poona decreased or remained constant at 4 degrees C for up to 21 days . Results demonstrate that persistence and growth of S . Poona on intact, wounded, and decaying cantaloupe rind are not markedly affected by the presence of molds.

Int J Food Microbiol, 2005 Jan 1, 97(3), 297 - 305
Antimicrobial resistance in Salmonella enteritidis strains isolated from broiler carcasses, food, human and poultry-related samples; Dias de Oliveira S et al.; Antimicrobial resistance was investigated in 91 Salmonella enteritidis isolates from broiler carcasses, food, human and poultry-related samples originated from South of Brazil . A great proportion of resistant strains was found, 90.1% showing resistance to at least one antimicrobial drug . There was a high resistance to sulfonamides (75.8%) and nitrofurantoin (52.8%) . Lower levels of resistance were found for tetracycline (15.4%), streptomycin (7.7%), nalidixic acid (7.7%), gentamicin (5.5%), norfloxacin (3.3%), trimethoprim (3.3%), cefalotin (2.2%), ampicillin (1.1%), and chloramphenicol (1.1%) . Resistance to ciprofloxacin was not detected . A total of 51.6% of S . enteritidis strains were multiresistant (resistance to two or more antimicrobial agents) and 18 resistance patterns were found . The highest resistance was found in strains isolated from poultry-related samples, where all strains were resistant to at least one antimicrobial agent . No predominant resistance pattern was related to phage type in our isolates . The high number of antimicrobial resistant S . enteritidis found in Southern Brazil indicates the need for the prudent drugs uses to diminish the development and spread of antimicrobial resistance.

Food Chem Toxicol, 2005 Jan, 43(1), 49 - 56
Mutagenicity evaluation of the commercial product CI Disperse Blue 291 using different protocols of the Salmonella assay; de Aragao Umbuzeiro G et al.; Textile dyes can enter the water ecosystem through wastewater discharges potentially exposing humans through the consumption of water and food . The commercial disperse dye product CI Disperse Blue 291 containing the aminoazobenzene 2-{(2-bromo-4,6-dinitrophenyl)azo}-5-(diethylamino)-4-methoxyacetanilide (CAS registry no . 56548-64-2) was tested for mutagenic activity in the Salmonella assay . We used strains with different levels of nitroreductase and O-acetyltransferase (i.e., TA98DNP6, YG1024, and YG1041) that are relevant enzymes in the activation of nitrocompounds by the intestinal microflora . The commercial product tested also was mutagenic for TA1537, TA1538, TA98 and TA100 . Presence of the pKM101 plasmid and the addition of S9 enhanced the mutagenic response . Specialized strains showed that both nitroreductase and O-acetyltransferase are important in activation of the product . The highest potency obtained was 240 revertants per microgram for YG1041 in the presence of S9 . Besides being able to cause frameshift mutations (hisd3052), the dye was able to cause all types of base pair substitution with a preference for TA to AT; CG to TA and CG to AT changes . With these results clearly showing that the bacterial nitroreductase and O-acetyltransferase metabolites of this compound are mutagenic, there is a need to test this dye using in vivo systems to verify possible adverse effects of this product in mammalian tissues.

Physiol Behav, 2004 Dec 15, 83(3), 495 - 504
A profile of the immediate endocrine, metabolic and behavioural responses following a dual exposure to endotoxin in early life; Walker FR et al.; Dual exposure to endotoxin on postnatal days (PNDs) 3 and 5 is increasingly being used to model the impact of bacterial challenge, in early life, on long-term health outcomes . Currently, however, little is known about how exposure to endotoxin using this model disrupts systems known to program physiological alterations in later life . The aim of the current study was to define, in Fischer 344 rat pups, a framework of the immediate endocrine, metabolic, and behavioural consequences following challenge with 0.05 mg/kg of endotoxin (Salmonella enteritidis) on PNDs 3 and 5 . Circulating corticosterone in endotoxin challenged neonates was significantly elevated at all time points assessed on PND 3 (P<0.05), however, by PND 5 this response was attenuated showing a significant elevation only at 4-h post-injection . In these same pups, glucose levels were significantly reduced by 8-h post-injection on PND 3 and remained significantly lower until 8-h post-injection on PND 5 (P<0.05) . Finally, the dams of endotoxin challenged pups, exhibited significantly less arched back nursing (P<0.05) but increased levels of off-nest time across the challenge period (P<0.05) . These findings demonstrate that postnatal endotoxin exposure impacts on both endocrine and metabolic activity and that alterations in these two systems may in part be mediated by the impact of endotoxin exposure on maternal behaviour.

Can J Vet Res, 2004 Oct, 68(4), 241 - 8
Distribution of Salmonella in tissues following natural and experimental infection in pigs; Cote S et al.; Clinical salmonellosis associated with Salmonella is increasingly reported in finishing swine . Since S . Typhimurium is often associated with these episodes and given that this serotype is among the most often reported in humans, we were interested to determine if various tissues and carcasses from animals coming from herds that were clinically affected were more likely to be contaminated by Salmonella compared to carcasses from animals raised in herds without any history of salmonellosis . Carcasses from animals from affected herds were significantly more contaminated by Salmonella while showing increased titers in antibodies directed against this bacterium . At the opposite, caecal contents and mesenteric lymph nodes from both groups of animals were similarly contaminated by Salmonella . In the second part of the study, we studied the persistence of the bacterium in various tissues after an experimental infection with S . Typhimurium . We found that, after the infection, Salmonella persisted for as many as 7 d in many extraintestinal tissues, while it was present in the feces of infected animals for all 14 d of the experiment . These findings indicated that carcasses from animals that experienced salmonellosis during their growth phase are more likely to be contaminated by this bacterium and that precautions must be taken in order to ensure that clinically affected animals should be kept on the farm for at least 7 d before being shipped for slaughter.

Appl Microbiol Biotechnol . 2004 Dec 2; {Epub ahead of print}
Bioactive berry compounds-novel tools against human pathogens; Puupponen-Pimia R et al.; Berry fruits are rich sources of bioactive compounds, such as phenolics and organic acids, which have antimicrobial activities against human pathogens . Among different berries and berry phenolics, cranberry, cloudberry, raspberry, strawberry and bilberry especially possess clear antimicrobial effects against, e.g . Salmonella and Staphylococcus . Complex phenolic polymers, like ellagitannins, are strong antibacterial agents present in cloudberry and raspberry . Several mechanisms of action in the growth inhibition of bacteria are involved, such as destabilisation of cytoplasmic membrane, permeabilisation of plasma membrane, inhibition of extracellular microbial enzymes, direct actions on microbial metabolism and deprivation of the substrates required for microbial growth . Antimicrobial activity of berries may also be related to antiadherence of bacteria to epithelial cells, which is a prerequisite for colonisation and infection of many pathogens . Antimicrobial berry compounds may have important applications in the future as natural antimicrobial agents for food industry as well as for medicine . Some of the novel approaches are discussed.

Biol Pharm Bull, 2004 Dec, 27(12), 1965 - 9
Antimicrobial activity of 10 different plant polyphenols against bacteria causing food-borne disease; Taguri T et al.; The antibacterial activities of 10 different plant polyphenols were evaluated by comparing their minimum inhibitory concentrations (MICs) against several food-borne pathogenic bacteria, Staphylococcus aureus (20 strains), some serotypes of the genus Salmonella (26 strains), Escherichia coli (23 strains), and some species of the genus Vibrio (27 strains) . The polyphenols examined were epigallocatechin (1), epigallocatechin-3-O-gallate (2), punicalagin (3), tannic acid (4), castalagin (5), prodelphinidin (6), geraniin (7), procyanidins (8), a theaflavin mixture of black tea (9), and green tea polyphenols treated with loquat polyphenol oxidase (10) . The average MICs of all polyphenols against S . aureus and the genus Vibrio (192+/-91 and 162+/-165 microg/ml, respectively) were much lower than the values against the genus Salmonella and E . coli (795+/-590 and 1519+/-949 microg/ml, respectively) (p<0.01) . The coefficient of variation of the MICs of all polyphenols against S . aureus was the least and that against the genus Vibrio was the greatest . The mean MICs of each plant polyphenol against S . aureus (98-389 microg/ml) and the genus Vibrio (68-488 microg/ml) were similar . The relatively lower mean MIC values of 1, 2, 5, and 6 suggest the importance of 3,4,5-trihydroxyphenyl groups in antibacterial activity.

J Bacteriol, 2004 Dec, 186(24), 8516 - 23
Hot spot for a large deletion in the 18- to 19-centisome region confers a multiple phenotype in Salmonella enterica serovar Typhimurium strain ATCC 14028; Murray SR et al.; Loss of the Salmonella MsbB enzyme, which catalyzes the incorporation of myristate destined for lipopolysaccharide in the outer membrane, results in a strong phenotype of sensitivity to salt and chelators such as EGTA and greatly diminished endotoxic activity . MsbB- salmonellae mutate extragenically to EGTA-tolerant derivatives at a frequency of 10(-4) per division . One of these derivatives arose from inactivation of somA, which suppresses sensitivity to salt and EGTA . Here we show that a second mode of MsbB- suppression is a RecA-dependent deletion between two IS200 insertion elements present in Salmonella enterica serovar Typhimurium strain ATCC 14028 but not in two other wild-type strains, LT2 and SL1344, which lack one of the IS200 elements . This deletion occurs spontaneously in wild-type and MsbB- strain 14028 salmonellae and accounts for about one-third of all of the spontaneous suppressors of MsbB- in strain 14028 . It spans the region corresponding to 17.7 to 19.9 centisomes, which includes somA, on the sequenced map of Salmonella LT2 (136 ORFs in that strain; ATCC 14028 and other strains showed variability in this region) . In addition to conferring EGTA resistance correlated with somA, the deletion confers a MacConkey galactose resistance phenotype on MsbB- Salmonella, indicating that at least one additional gene (distinct from somA) within the deletion is responsible for this phenotype . In the wild type, the deletion mutant grows with normal exponential growth rate in Luria broth but is chlorate resistant and does not grow on citrate agar . The deletion strains have lost hydrogen sulfide production, nitrate reductase activity, and gas production from glucose fermentation.

Proc Natl Acad Sci U S A, 2004 Dec 14, 101(50), 17492 - 7 Epub 2004 Dec 02.
Vi polysaccharide of Salmonella typhi targets the prohibitin family of molecules in intestinal epithelial cells and suppresses early inflammatory responses; Sharma A et al.; Vi capsular polysaccharide (Vi) was first identified as a virulence antigen of Salmonella typhi, the causative agent of typhoid fever in humans; it renders S . typhi resistant to phagocytosis and the action of serum complement . However, the role of Vi during the infection of intestinal epithelium with S . typhi is not completely understood . We show here that Vi can interact with a model human intestinal epithelial cell line, Caco-2, through a cell-surface-associated molecular complex containing two major proteins of 30 and 35 kDa and a minor protein of approximately 68 kDa . The two major proteins were identified as the putative tumor suppressor molecule, prohibitin, and its closely related homolog, B cell receptor-associated protein 37 . These two proteins were enriched in lipid rafts, and Vi readily associated with these membrane microdomains . Engagement of Caco-2 cells with Vi inhibited their ability to produce an inflammatory response upon infection with Vi(-) S . typhi . Consistent with this effect, infection of Caco-2 cells with Vi(+) S . typhi produced less IL-8 compared with Vi(-) S . typhi . Cells treated with Vi showed reduced extracellular signal-regulated kinase phosphorylation in response to infection with Vi(-) S . typhi or stimulation with phorbol 12-myristate 13-acetate, suggesting that the mitogen-activated protein kinase pathway might be a target for Vi-mediated inhibition of inflammatory responses . These findings reveal a crucial role for Vi in the modulation of early inflammatory responses during infection with S . typhi . This kind of a modulation could play a significant role in the establishment of infection by S . typhi.

Appl Environ Microbiol, 2004 Dec, 70(12), 7046 - 52
Diagnostic real-time PCR for detection of Salmonella in food; Malorny B et al.; A robust 5' nuclease (TaqMan) real-time PCR was developed and validated in-house for the specific detection of Salmonella in food . The assay used specifically designed primers and a probe target within the ttrRSBCA locus, which is located near the Salmonella pathogenicity island 2 at centisome 30.5 . It is required for tetrathionate respiration in Salmonella . The assay correctly identified all 110 Salmonella strains and 87 non-Salmonella strains tested . An internal amplification control, which is coamplified with the same primers as the Salmonella DNA, was also included in the assay . The detection probabilities were 70% when a Salmonella cell suspension containing 10(3) CFU/ml was used as a template in the PCR (5 CFU per reaction) and 100% when a suspension of 10(4) CFU/ml was used . A pre-PCR sample preparation protocol including a preenrichment step in buffered peptone water followed by DNA extraction-purification was applied when 110 various food samples (chicken rinses, minced meat, fish, and raw milk) were investigated for Salmonella . The diagnostic accuracy was shown to be 100% compared to the traditional culture method . The overall analysis time of the PCR method was approximately 24 h, in contrast to 4 to 5 days of analysis time for the traditional culture method . This methodology can contribute to meeting the increasing demand of quality assurance laboratories for standard diagnostic methods . Studies are planned to assess the interlaboratory performance of this diagnostic PCR method.

J Antimicrob Chemother, 2005 Jan, 55(1), 119 - 122 Epub 2004 Dec 1.
Integron-mediated ESBL resistance in rare serotypes of Escherichia coli causing infections in an elderly population of Israel; Sompolinsky D et al.; OBJECTIVES: To identify and characterize the aetiology of an outbreak of extra-intestinal multidrug-resistant Escherichia coli infections in elderly patients in Israel . METHODS: Extended-spectrum beta-lactamase (ESBL)-producing clinical isolates of E . coli from extra-intestinal sources were tested for susceptibility to non-beta-lactam drugs, and their serotypes were determined . Restriction enzyme digestion, followed by PFGE of DNA purified from isolates, was used to classify the phylogenetic relationship between them . Plasmid DNA from five isolates of different serotypes was used to transform an E . coli laboratory strain . The plasmids were partially sequenced . RESULTS: E . coli isolates from 86 patients, mostly elderly, were shown to be positive for inhibitor-susceptible ESBLs, and more resistant to cefotaxime than to ceftazidime . Ninety-six per cent of ESBL producers were also resistant to gentamicin, and 100% to trimethoprim/sulfamethoxazole and ciprofloxacin . All isolates belonged to one of five serotypes . PFGE analysis of purified DNA yielded 17 profiles . Sequencing of plasmids isolated from the transformants identified sul1, aac(6')-Ib and bla(CTX-M-2) . These genes were embedded in an integron, InS21 . CONCLUSIONS: Extra-intestinal infections with ESBL-producing E . coli of different serotypes and probably mixed clonality showed a surprising homogeneity in resistance profiles, with 100% being co-resistant to ciprofloxacin and trimethoprim/sulfamethoxazole, and 96% to gentamicin . Plasmid DNA from three isolates from different serotypes contained integron InS21, previously demonstrated in Salmonella enterica from Argentina . This is the first molecular identification of an ESBL gene and integron in Israel or neighbouring geographical areas.

Commun Dis Intell, 2004, 28(3), 401 - 5
OzFoodNet: enhancing foodborne disease surveillance across Australia: quarterly report, April to June 2004; The mutagenic hazards of settled house dust: a review; Mutagenesis Section, Safe Environments Program, Health Canada, Tunney's Pasture 0803A, Ottawa, Ont., Canada K1A 0L2Given the large proportion of time people spend indoors, the potential health risks posed by chemical contaminants in the indoor environment are of concern . Research suggests that settled house dust (SHD) may be a significant source for indoor exposure to hazardous substances including polycyclic aromatic hydrocarbons (PAHs) . Here, we summarize the literature on the mutagenic hazards of SHD and the presence of PAHs in dust . We assess the extent to which PAHs are estimated to contribute to the mutagenicity of SHD, and evaluate the carcinogenic risks associated with exposures to PAHs in SHD . Research demonstrates that SHD has a Salmonella TA98 mutagenic potency of 1000-7000 revertants/g, and contains between 0.5 and 500 microg/g of PAHs . Although they only account for a small proportion of the variability, analyses of pooled datasets suggest that cigarette smoking and an urban location contribute to higher levels of PAHs . Despite their presence, our calculations show that PAHs likely account for less than 25% of the overall mutagenic potency of dust . Nevertheless, carcinogenic PAHs in dust can pose potential health risks, particularly for children who play and crawl on dusty floors, and exhibit hand-to-mouth behaviour . Risk assessment calculations performed in this study reveal that the excess cancer risks from non-dietary ingestion of carcinogenic PAHs in SHD by preschool aged children is generally in the range of what is considered acceptable (1 x 10(-6) to 2 x 10(-6)) . Substantially elevated risk estimates in the range 1.5 x 10(-4) to 2.5 x 10(-4) correspond only to situations where the PAH content is at or beyond the 95th percentile, and the risk estimates are adjusted for enhanced susceptibility at early life stages . Analyses of SHD and its contaminants provide an indication of indoor pollution and present important information for human exposure assessments.

Mutat Res, 2004 Nov, 567(2-3), 347 - 99
The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicity; Claxton LD et al.; Mutagens in urban air pollution come from anthropogenic sources (especially combustion sources) and are products of airborne chemical reactions . Bacterial mutation tests have been used for large, multi-site, and/or time series studies, for bioassay-directed fractionation studies, for identifying the presence of specific classes of mutagens, and for doing site- or source-comparisons for relative levels of airborne mutagens . Early research recognized that although carcinogenic PAHs were present in air samples they could not account for the majority of the mutagenic activity detected . The mutagenicity of airborne particulate organics is due to at least 500 identified compounds from varying chemical classes . Bioassay-directed fractionation studies for identifying toxicants are difficult to compare because they do not identify all of the mutagens present, and both the analytical and bioassay protocols vary from study to study . However, these studies show that the majority of mutagenicity is usually associated with moderately polar/highly polar classes of compounds that tend to contain nitroaromatic compounds, aromatic amines, and aromatic ketones . Smog chamber studies have shown that mutagenic aliphatic and aromatic nitrogen-containing compounds are produced in the atmosphere when organic compounds (even non-mutagenic compounds) are exposed to nitrogen oxides and sunlight . Reactions that occur in the atmosphere, therefore, can have a profound effect on the genotoxic burden of ambient air . This review illustrates that the mutagenesis protocol and tester strains should be selected based on the design and purpose of the study and that the correlation with animal cancer bioassay results depends upon chemical class . Future emphasis needs to be placed on volatile and semi-volatile genotoxicants, and on multi-national studies that identify, quantify, and apportion mutagenicity . Initial efforts at replacing the Salmonella assay for ambient air studies with some emerging technology should be initiated.

Mutat Res, 2004 Nov, 567(2-3), 227 - 345
Mutagens in contaminated soil: a review; White PA et al.; The intentional and accidental discharges of toxic pollutants into the lithosphere results in soil contamination . In some cases (e.g., wood preserving wastes, coal-tar, airborne combustion by-products), the contaminated soil constitutes a genotoxic hazard . This work is a comprehensive review of published information on soil mutagenicity . In total, 1312 assessments of genotoxic activity from 118 works were examined . The majority of the assessments (37.6%) employed the Salmonella mutagenicity test with strains TA98 and/or TA100 . An additional 37.6% of the assessments employed a variety of plant species (e.g., Tradescantia clone 4430, Vicia faba, Zea mays, Allium cepa) to assess mutagenic activity . The compiled data on Salmonella mutagenicity indicates significant differences (p<0.0001) in mean potency (revertents per gram dry weight) between industrial, urban, and rural/agricultural sites . Additional analyses showed significant empirical relationships between S9-activated TA98 mutagenicity and soil polycyclic aromatic hydrocarbon (PAH) concentration (r2=0.19 to 0.25, p<0.0001), and between direct-acting TA98 mutagenicity and soil dinitropyrene (DNP) concentration (r2=0.87, p<0.0001) . The plant assay data revealed excellent response ranges and significant differences between heavily contaminated, industrial, rural/agricultural, and reference sites, for the anaphase aberration in Allium cepa (direct soil contact) and the waxy locus mutation assay in Zea mays (direct soil contact) . The Tradescantia assays appeared to be less responsive, particularly for exposures to aqueous soil leachates . Additional data analyses showed empirical relationships between anaphase aberrations in Allium, or mutations in Arabidopsis, and the 137Cs contamination of soils . Induction of micronuclei in Tradescantia is significantly related to the soil concentration of several metals (e.g., Sb, Cu, Cr, As, Pb, Cd, Ni, Zn) . Review of published remediation exercises showed effective removal of genotoxic petrochemical wastes within one year . Remediation of more refractory genotoxic material (e.g., explosives, creosote) frequently showed increases in mutagenic hazard that remained for extended periods . Despite substantial contamination and mutagenic hazards, the risk of adverse effect (e.g., mutation, cancer) in humans or terrestrial biota is difficult to quantify.

Mutat Res, 2004 Nov, 567(2-3), 151 - 225
The mutagenic hazards of aquatic sediments: a review; Chen G et al.; Sediments are the sink for particle-sorbed contaminants in aquatic systems and can serve as a reservoir of toxic contaminants that continually threaten the health and viability of aquatic biota . This work is a comprehensive review of published studies that investigated the genotoxicity of sediments in rivers, lakes and marine habitats . The Salmonella mutagenicity test is the most frequently used assay and accounts for 41.1% of the available data . The Salmonella data revealed mutagenic potency values for sediment extracts (in revertants per gram dry weight) that spans over seven orders of magnitude from not detectable to highly potent (10(5) rev/g) . Analyses of the Salmonella data (n=510) showed significant differences between rural, urban/industrial, and heavily contaminated (e.g., dump) sites assessed using TA98 and TA100 with S9 activation . Additional analyses showed a significant positive correlation between Salmonella mutagenic potency (TA98 and TA100 with S9) and PAH contamination (r2=0.19-0.68) . The second and third most commonly used assays for the analysis of sediments and sediment extracts are the SOS Chromotest (9.2%) and the Mutatox assays (7.8%), respectively . These assays are frequently used for rapid initial screening of collected samples . A variety of other in vitro endpoints employing cultured fish and mammalian cells have been used to investigate sediment genotoxic activity . Endpoints investigated include sister chromatid exchange frequency, micronucleus frequency, chromosome aberration frequency, gene mutation at tk and hprt loci, unscheduled DNA synthesis, DNA adduct frequency, and DNA strand break frequency . More complex in vivo assays have documented a wide range of effects including neoplasms and preneoplastic lesions in fish and invertebrate exposed ex situ . Although costly and time consuming, these assays have provided definitive evidence linking sediment contamination and a variety of genotoxic and carcinogenic effects observed in situ.

Mutat Res, 2004 Nov, 567(2-3), 109 - 49
Mutagens in surface waters: a review; Ohe T et al.; A review of the literature on the mutagenicity/genotoxicity of surface waters is presented in this article . Subheadings of this article include a description of sample concentration methods, mutagenic/genotoxic bioassay data, and suspected or identified mutagens in surface waters published in the literature since 1990 . Much of the published surface water mutagenicity/genotoxicity studies employed the Salmonella/mutagenicity test with strains TA98 and/or TA100 with and/or without metabolic activation . Among all data analyzed, the percentage of positive samples toward TA98 was approximately 15%, both in the absence and the presence of S9 mix . Those positive toward TA100 were 7%, both with and without S9 mix . The percentage classified as highly mutagenic (2500-5000 revertants per liter) or extremely mutagenic (more than 5000 revertants per liter) was approximately 3-5% both towards TA98 and TA100, regardless of the absence or the presence of S9 mix . This analysis demonstrates that some rivers in the world, especially in Europe, Asia and South America, are contaminated with potent direct-acting and indirect-acting frameshift-type and base substitution-type mutagens . These rivers are reported to be contaminated by either partially treated or untreated discharges from chemical industries, petrochemical industries, oil refineries, oil spills, rolling steel mills, untreated domestic sludges and pesticides runoff . Aquatic organisms such as teleosts and bivalves have also been used as sentinels to monitor contamination of surface water with genotoxic chemicals . DNA modifications were analyzed for this purpose . Many studies indicate that the 32P-postlabeling assay, the single cell gel electrophoresis (comet) assay and the micronucleus test are sensitive enough to monitor genotoxic responses of indigenous aquatic organisms to environmental pollution . In order to efficiently assess the presence of mutagens in the water, in addition to the chemical analysis, mutagenicity/genotoxicity assays should be included as additional parameters in water quality monitoring programs . This is because according to this review they proved to be sensitive and reliable tools in the detection of mutagenic activity in aquatic environment . Many attempts to identify the chemicals responsible for the mutagenicity/genotoxicity of surface waters have been reported . Among these reports, researchers identified heavy metals, PAHs, heterocyclic amines, pesticides and so on . By combining the blue cotton hanging method as an adsorbent and the O-acetyltransferase-overproducing strain as a sensitive strain for aminoarenes, Japanese researchers identified two new type of potent frameshift-type mutagens, formed unintentionally, in several surface waters . One group has a 2-phenylbenzotriazole (PBTA) structure, and seven analogues, PBTA-type mutagens, were identified in surface waters collected at sites below textile dyeing factories and municipal wastewater treatment plants treating domestic wastes and effluents . The other one has a polychlorinated biphenyl (PCB) skelton with nitro and amino substitution group and it was revealed to be 4-amino-3,3'-dichloro-5,4'-dinitrobiphenyl derived from chemical plants treating polymers and dye intermediates . However, the identification of major putative mutagenic/genotoxic compounds in most surface waters with high mutagenic/genotoxic activity in the world have not been performed . Further efforts on chemical isolation and identification by bioassay-directed chemical analysis should be performed.

Dev Comp Immunol, 2005, 29(3), 255 - 64
CpG-oligodeoxynucleotide-stimulated chicken heterophil degranulation is serum cofactor and cell surface receptor dependent; He H et al.; Synthetic oligodeoxynucleotide containing unmethylated CpG motif (CpG-ODN) is immune stimulatory to chicken heterophils . Recognition of CpG-ODN by chicken heterophils leads to the mobilization and release of granules . This CpG-ODN-induced heterophil degranulation was chicken serum (CS)-dependent . Heat-denaturation and membrane filtration of CS revealed that the active serum cofactor(s) was likely a protein in nature with a molecule mass within 50,000 to 100,000 . This serum cofactor(s) was heat-resistant at 56 degrees C for 1h . The involvement of a cell surface receptor in recognition of CpG-ODN was also demonstrated by (1) trypsin treatment of the heterophils abrogated the degranulation response and (2) CpG-ODN-induced heterophil degranulation was sensitive to the inhibition of Clathrin-dependent endocytosis . In addition, among various microbial agonists, including CpG-ODN, lipopolysaccharide, lipoteichoic acid, phorbol myristate acetate, and formalin-killed Salmonella enteritidis, CpG-ODN was the only agonist that displayed serum-dependent induction of degranulation in chicken heterophils . This is the first report that shows serum-dependent activation of leukocytes by CpG-ODN.

Eur J Med Chem, 2004 Dec, 39(12), 1073 - 7
Organoiodine (III) mediated synthesis of 3-aryl/hetryl-5,7-dimethyl-1,2,4-triazolo{4,3-a}pyrimidines as antibacterial agents; Prakash O et al.; Synthesis of some new 3-aryl/hetryl-5,7-dimethyl-1,2,4-triazolo{4,3-a}pyrimidines (3a-k) has been accomplished by the oxidation of 4,6-dimethyl-2-pyrimidinylhydrazones of various aldehydes with iodobenzene diacetate in dichloromethane . Nine new compounds (3b-g and 3i-k) were tested in vitro for their antibacterial activity . Two compounds, namely 3-(4'-pyridyl)-5,7-dimethyl-1,2,4-triazolo{4,3-a}pyrimidine (3k) and 3-(3',4'-dimethoxyphenyl)-5,7-dimethyl-1,2,4-triazolo{4,3-a}pyrimidine (3f), were associated with substantially higher antibacterial activity than some commercial antibiotics against Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Salmonella typhi at MIC (minimum inhibitory concentration) i.e . 10 microg/ml.

N Z Med J . 2004 Nov 5;117(1205):U1144.
Salmonella Brandenburg: changing patterns of disease in Southland Province, New Zealand; Clarke R et al.; BACKGROUND: Salmonella Brandenburg has previously been an infrequent human pathogen in New Zealand, however a marked increase in human isolates has been noted since 1996 . AIM: To research the incidence and pattern of Salmonella Brandenburg infection in New Zealand and specifically the characteristics of human isolates seen at Southland Hospital, Invercargill, Southland Province, New Zealand . METHODS: A literature review was performed, and statistical data from the Enteric Reference Laboratory, Institute of Environmental Science and Research Limited (ESR) was reviewed . A retrospective case series was performed, collecting demographic and clinical information for all patients with salmonellosis seen at Southland Hospital between September 1997 and May 2002 . RESULTS: Salmonella Brandenburg is shown to have become the predominant human isolate seen at Southland Hospital from 1997 to 2001 . Of a total of 62 cases of salmonellosis, 30 were culture-positive for S . Brandenburg (48%) . Of these cases, 13 (43%) were from extra-intestinal sites . Eleven of these 13 (85%) cases did not have any risk factors for invasive disease . During the study period, the incidence of S . Brandenburg infection increased, as did the incidence of invasive disease . CONCLUSION: The incidence and invasive potential of S . Brandenburg seems to be increasing, particularly in Southland, with peak infection rates corresponding to the lambing and calving season (September to November) . S . Brandenburg seen in immunocompetent hosts may be a more invasive organism, and present with a wider spectrum of disease than has been previously considered.

Proc Natl Acad Sci U S A, 2004 Dec 7, 101(49), 17162 - 7 Epub 2004 Dec 7.
Phenotypic differences between Salmonella and Escherichia coli resulting from the disparate regulation of homologous genes; Winfield MD et al.; Phenotypic differences among closely related bacteria have been largely ascribed to species-specific genes, such as those residing in pathogenicity islands . However, we now report that the differential regulation of homologous genes is the mechanism responsible for the divergence of the enteric bacteria Salmonella enterica and Escherichia coli in their ability to make LPS modifications mediating resistance to the antibiotic polymyxin B . In S . enterica serovar Typhimurium, the PmrA/PmrB two-component system governing polymyxin B resistance is induced in low Mg(2+) in a process that requires the PmrD protein and by Fe(3+) in a PmrD-independent fashion . We establish that E . coli K-12 induces PmrA-activated gene transcription and polymyxin B resistance in response to Fe(3+), but that it is blind to the low Mg(2+) signal . The highly divergent PmrD protein is responsible for this phenotype as replacement of the E . coli pmrD gene by its Salmonella counterpart resulted in an E . coli strain that transcribed PmrA-activated genes and displayed polymyxin B resistance under the same conditions as Salmonella . Molecular analysis of natural isolates of E . coli and Salmonella revealed that the PmrD proteins are conserved within each genus and that selection might have driven the divergence between the Salmonella and E . coli PmrD proteins . Investigation of PmrD function demonstrated statistically different distributions for the Salmonella and E . coli isolates in PmrD-dependent transcription occurring in low Mg(2+) . Our results suggest that the differential regulation of conserved genes may have ecological consequences, determining the range of niches a microorganism can occupy.

Int Immunol, 2005 Jan, 17(1), 85 - 93 Epub 2005 Jan.
Release kinetics and cell trafficking in relation to bacterial growth explain the time course of blood neutrophils and monocytes during primary Salmonella infection; Takumi K et al.; Granulocytes and neutrophils are predominantly responding cells during the early phase of infection of rats with Salmonella . We propose mathematical and experimental models of the kinetics of neutrophil and monocyte responses in Salmonella infection via the oral route . Using the models, we estimate that approximately 1 in 500 inoculated Salmonella cells actually infected the rat and multiplied with a doubling time of 5 h in Peyer's patches, reaching a maximum of approximately 10(6) c.f.u./g . In low-dose infection, neutrophil and monocyte responses are delayed, but further resemble the responses in high-dose infection . Important processes influencing neutrophil and monocyte recruitment are: massive migration into the infected tissue, and non-linear release kinetics of neutrophils and monocytes from the bone marrow . In conclusion, we can predict time series of neutrophil and monocyte responses in low-dose and high-dose experimental infection via the oral route.

J Leukoc Biol . 2004 Nov 29; {Epub ahead of print}
Impact of LL-37 on anti-infective immunity; Bowdish DM et al.; Host defense peptides (often called cationic antimicrobial peptides) have pleiotropic immunomodulatory functions . The human host defense peptide LL-37 is up-regulated at sites of infection and has little or no antimicrobial activity in tissue-culture media but under the same conditions, demonstrates immunomodulatory effects on epithelial cells, monocytes, and dendritic cells (DC) . These effects include the induction of chemokine production in a mitogen-activated protein kinase-dependent manner in epithelial cell lines and monocytes and profound alterations of DC differentiation, resulting in the capacity to enhance a T helper cell type 1 response . Although the exact mechanisms of interaction between LL-37 and these cell types have not been elucidated, there is evidence for specific (i.e., receptor-mediated) and nonspecific interactions . The relative significance of the direct antimicrobial activities and immunomodulatory properties of LL-37 and other cationic host defense peptides in host defense remains unresolved . To demonstrate that antimicrobial activity was not necessarily required for the protection in vivo, model peptides were synthesized and tested for antimicrobial and immunomodulatory activities . A peptide with no antimicrobial activity was found to be protective in animal models of Staphylococcus aureus and Salmonella infection, implying that a host defense peptide can protect by exerting immunomodulatory properties.

J Biol Chem . 2004 Nov 29; {Epub ahead of print}
Signal-dependent binding of the response regulators PhoP and PmrA to their target promoters in vivo; Shin D et al.; Low Mg2+ promotes phosphorylation of the response regulators PhoP and PmrA and transcription of their activated genes in Salmonella enterica . Using chromatin immunoprecipitation (ChIP), we have now determined that the PhoP and PmrA proteins are recruited to the regulatory region of their target genes when bacteria experience low Mg(2+) but not when they are grown in high Mg(2+) . Even when the PhoP protein was artificially produced at four-fold higher levels than the wild-type strain, promoter occupancy required the low Mg(2+) signal . Substitution of the predicted phosphorylation site D52 with a valine residue abolished phosphorylation of the PhoP protein, resulting in loss of PhoP binding to target promoters and transcription of PhoP-activated genes . Our results indicate that the promoter binding ability of the PhoP and PmrA proteins occurring in low Mg(2+) is correlated with phosphorylation of these proteins in vivo.

Immunobiology, 2004, 209(7), 523 - 33
Prolactin modulates IL-8 production induced by porins or LPS through different signaling mechanisms; D'Isanto M et al.; Prolactin (PRL) induces cell proliferation and cell differentiation through the well-known mitogen-activated protein kinases (MAPKs) and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways, depending on the cell line . MAPKs play a central role in signaling transduction mechanisms that transmit mitogenic or differentiation signals from an activated receptor to the intracellular machinery . All of the cytokine receptors that activate the JAK/STAT pathway also activate the MAPK pathway . The aim of the present study was to delineate the signal pathways implicated in IL-8 release by THP-1 cells, pretreated with PRL, after stimulation with either lipopolysaccharide (LPS) or porins from Salmonella enterica serovar Typhimurium . PRL activates the JAK2/STAT1-3 signaling pathway, while LPS or porins from S . enterica serovar Typhimurium does not induce any phosphorylation of this pathway . However, in THP-1 cells, the combination of PRL followed by either S . enterica serovar Typhimurium LPS or porins produced a greater MEK1-MEK2/MAPKs activation response than treatment with PRL alone . Similarly, PRL pretreatment of THP-1 cells resulted in an increase in IL-8 release in response to stimulation with either LPS or porins . This additive effect on IL-8 release was reduced when the cells were also treated with PD-098059, a selective inhibitor of the MEK1 activator and the MAPK cascade, or SB203580, a specific inhibitor of the p38 pathway, or AG490, a specific JAK/STAT pathway inhibitor, providing evidence that there are different signal pathways activated which have a cumulative effect.

Di Yi Jun Yi Da Xue Xue Bao, 2004 Nov, 24(11), 1311 - 2, 1315
{Changes in myocardial enzyme spectrum and electrocardiogram after Salmonella food poisoning.}; Sun ZB et al.; OBJECTIVE: To study the changes in myocardial enzyme spectrum in relation to electrocardiogram (ECG) in Salmonella food poisoning . METHODS: The myocardial enzyme spectrum and ECG of 56 patients with Salmonella food poisoning were examined, with 34 normal subjects serving as the control group . RESULTS: In the food poisoning group, the myocardial enzyme activities was increased in 36 cases (64.29%) within 2 days after the poisoning and the ECG of 33 cases (58.93%) showed abnormal changes within 1-4 days . The levels of creatine phosphoskinase (CPK) and alpha-hydroxybutyrate acid dehydrogenase (alpha-HBDH) in poisoning group were obviously higher than those in the control group (P<0.01) . CONCLUSION: Routine examination of myocardial enzyme spectrum and ECG helps define early changes in patients with Salmonella food poisoning for clinical treatment decision.

Di Yi Jun Yi Da Xue Xue Bao, 2004 Nov, 24(11), 1257 - 9
{Detection of the Salmonella invasion gene invA using molecular beacon probe.}; Wan CS et al.; OBJECTIVE: To detect Salmonella invasion gene invA . METHODS: The invA gene of Salmonella was amplified with PCR reaction system containing the molecular beacon probe labeled with 6-carboxy fluorescein (6-FAM) at its 5' end and with (4-dimethylaminophenylazo)benzoic acid (DABCYL) at its 3' end, and the fluorescence signal was read at the end of PCR . RESULTS: The fluorescence values of S.enteritidis, S . paratyphi A, S . paratyphi B, S.typhi antigen H, S.typhi, and enteroinvasive E.coli were 161.6, 104.5, 85.9, 83.1, 94.8 and 46.1 respectively . The results of PCR of Salmonella was consistent with that of agarose gel electrophoresis . CONCLUSION: PCR with fluorogenic molecular beacon probe is rapid, specific, sensitive, and convenient for detecting Salmonella with invA gene.

Infect Genet Evol, 2005 Jan, 5(1), 1 - 9
Bacteriophage-encoded type III effectors in Salmonella enterica subspecies 1 serovar Typhimurium; Ehrbar K et al.; Salmonella spp . are Gram-negative bacteria which cause infections ranging from mild, self-limiting enterocolitis to systemic (typhoid) disease . Recent work has established that the genetic makeup varies considerably between different Salmonella strains . Phages play an important role in this diversity . In fact, Salmonella has emerged as a prime example for the involvement of virulence factor encoding phages in the emergence of new epidemic strains . Among other virulence factors, Salmonella enterica utilizes two specialized protein secretion systems termed type III secretion systems (TTSS) to deliver effector proteins into host cells which manipulate host cell signaling cascades . These two TTSS and several effectors are encoded within Salmonella pathogenicity islands 1 and 2 . Some effectors including SopE, SspH1, SseI and SopE2 are encoded by phages or phage remnants . These phage-encoded effectors seem to be transferred between different Salmonella strains . They have attracted much interest because they might contribute to the evolution of Salmonella spp . Here we will focus on SopEPhi which encodes the SPI-1 effector SopE . It provides an excellent example to illustrate how horizontally transferred effector proteins are integrated into the complex regulatory network of a TTSS in a recipient bacterium . Additional data supporting the hypothesis are presented . This is a prerequisite to allow optimization of the bacterium host cell interaction by reassortment of the phage-encoded effector protein repertoire.

Lancet Infect Dis, 2004 Dec, 4(12), 739 - 49
Human genetics of intracellular infectious diseases: molecular and cellular immunity against mycobacteria and salmonellae; van de Vosse E et al.; The ability to develop adequate immunity to intracellular bacterial pathogens is unequally distributed among human beings . In the case of tuberculosis, for example, infection with Mycobacterium tuberculosis results in disease in 5-10% of exposed individuals, whereas the remainder control infection effectively . Similar interindividual differences in disease susceptibility are characteristic features of leprosy, typhoid fever, leishmaniasis, and other chronic infectious diseases, including viral infections . The outcome of infection is influenced by many factors, such as nutritional status, co-infections, exposure to environmental microbes, and previous vaccinations . It is clear, however, that genetic host factors also play an important part in controlling disease susceptibility to intracellular pathogens . Recently, patients with severe infections due to otherwise poorly pathogenic mycobacteria (non-tuberculous mycobacteria or Mycobacterium bovis BCG) or Salmonella spp have been identified . Many of these patients were unable to produce or respond to interferon gamma, due to deleterious mutations in genes that encode major proteins in the type 1 cytokine (interleukin 12/interleukin 23/interferon gamma) axis (interleukin 12p40/interleukin 23p40, IL12 receptor beta1/IL23 receptor beta1, interferon gamma receptors 1 and 2, or signal transducer and activator of transcription 1) . This axis is a major immunoregulatory system that bridges innate and adaptive immunity . Unusual mycobacterial infections were also reported in several patients with genetic defects in inhibitor of NFkappaB kinase gamma, a key regulatory molecule in the nuclear factor kappaB pathway . New findings discussed in this review provide further and sometimes surprising insights into the role of type 1 cytokines, and into the unexpected heterogeneity seen in these syndromes.

Res Vet Sci, 2005 Apr, 78(2), 161 - 167
Acute toxoplasmosis in three wild arctic foxes (Alopex lagopus) from Svalbard; one with co-infections of Salmonella Enteritidis PT1 and Yersinia pseudotuberculosis serotype 2b; Sorensen KK et al.; Acute disseminated toxoplasmosis was diagnosed in three wild arctic foxes (Alopex lagopus) that were found dead in the same locality on Svalbard (Norway) . The animals included one adult female and two 4-months-old pups . The adult fox was severely jaundiced . Necropsy revealed multifocal, acute, necrotizing hepatitis, acute interstitial pneumonia, and scattered foci of brain gliosis, often associated with Toxoplasma tachyzoites . One pup also had Toxoplasma-associated meningitis . In addition, the latter animal was infected with Yersinia pseudotuberculosis serotype 2b and Salmonella Enteritidis phage type 1 (PT1), which may have contributed to the severity of the Toxoplasma infection in this animal . The diagnosis of toxoplasmosis was confirmed by positive immunohistochemistry and detection of anti-Toxoplasma gondii antibodies in serum of all foxes . The animals were negative for Neospora caninum, canine distemper virus, canine adenovirus, and rabies virus on immunolabelling of tissue sections and smears.

Ann Allergy Asthma Immunol, 2004 Nov, 93(5 Suppl 3), S26 - 32
Gastrointestinal immunopathology and food allergy; Bellanti JA et al.; OBJECTIVE: To review the current data that support the pivotal function of the gastrointestinal immune system in health and disease and its critical role in the pathogenesis of a wide variety of clinical disorders associated with food allergy (FA) . DATA SOURCES: Internet-based literature search and our own data . STUDY SELECTION: The studies included in this review were selected based on the expert opinion of the authors . RESULTS: In contrast to the beneficial expressions of gastrointestinal-associated lymphoid tissue, which are seen with relevance to newer methods of delivery of vaccines directly applied to the gastrointestinal mucosal surfaces (eg, oral poliovirus, rotavirus, Salmonella typhi vaccines), the adverse consequences of a mucosal immune response gone astray are evidenced in many diseases such as FA . A classification of clinical disorders associated with FA based on classic mechanisms of immunologic injury is presented, which includes the following: (1) IgE-mediated, (2) non-IgE-mediated, and (3) mixed IgE- and non-IgE-mediated disorders . Our study of immunologic disturbance in patients with non-IgE FA revealed a pattern of increased CD4+ and decreased TH1 cell counts in peripheral blood mononuclear cells in contrast to patients with celiac disease, where a pattern of increased CD8+ and TH1 cell counts in peripheral blood mononuclear cells and increased CD8+ cell counts was seen . CONCLUSIONS: The gastrointestinal immune response thus plays a pivotal role in maintaining protective immunity in health and a critical role in the pathogenesis of a wide variety of clinical disorders associated with FA.

PLoS Biol . 2004 Dec;2(12):e418 . Epub 2004 Nov 30.
Secreted Bacterial Effectors and Host-Produced Eiger/TNF Drive Death in aSalmonella-Infected Fruit Fly; Brandt SM et al.; Death by infection is often as much due to the host's reaction as it is to the direct result of microbial action . Here we identify genes in both the host and microbe that are involved in the pathogenesis of infection and disease in Drosophila melanogaster challenged with Salmonella enterica serovartyphimurium (S . typhimurium).We demonstrate that wild-typeS . typhimurium causes a lethal systemic infection when injected into the hemocoel of D . melanogaster . Deletion of the gene encoding the secreted bacterial effect or Salmonella leucine-rich (PslrP)changes an acute and lethal infection to one that is persistent and less deadly . We propose a model in which Salmonella secreted effectors stimulate the fly and thus cause an immune response that is damaging both to the bacteria and, subsequently, to the host . In support of this model, we show that mutations in the fly gene eiger, a TNF homolog, delay the lethality of Salmonella infection . These results suggest that S . typhimurium-infected flies die from a condition that resembles TNF-induced metabolic collapse in vertebrates . This idea provides us with a new model to study shock-like biology in a genetically manipulable host . In addition, it allows us to study the difference in pathways followed by a microbe when producing an acute or persistent infection.

Eur J Clin Microbiol Infect Dis, 2004 Nov, 23(11), 841 - 3 Epub 2004 Nov.
A foodborne outbreak of Salmonella enterica subsp . enterica serovar Madelia at a silver anniversary reception; Hauri AM et al.; Reported here is an outbreak of Salmonella enterica subsp . enterica serovar Madelia infection that occurred among 44 persons attending a silver anniversary reception in Hesse, Germany . Isolates of Salmonella Madelia are extremely unusual, and no outbreaks associated with this serotype have been reported previously . Forty-two attendees were interviewed and information was obtained from each of them regarding demographic and clinical characteristics and food consumed at the reception . Twenty-four attendees submitted stool samples for microbiological testing, and 10 of these were culture-positive for S . Madelia . Twenty-three attendees met the case definition of infection, while 18 met the clinical case definition (i.show $132#e . vomiting or diarrhoea within 3 days of consuming food at the reception) and five had asymptomatic infection with S . Madelia . The most likely vehicles of infection were tortellini and a red pesto sauce.

Cell Mol Life Sci, 2004 Nov, 61(22), 2812 - 26
Cellular microbiology of intracellular Salmonella enterica: functions of the type III secretion system encoded by Salmonella pathogenicity island 2; Kuhle V et al.; The facultative intracellular pathogen Salmonella enterica resides in a special membrane compartment of the host cell and modifies its host to achieve intracellular survival and proliferation . The type III secretion system encoded by Salmonella pathogenicity island 2 (SPI2) has a central role in the interference of intracellular Salmonella with host cell functions . SPI2 function affects antimicrobial defense mechanisms of the host, intracellular transport processes, integrity and function of the cytoskeleton and host cell death . These modifications are mediated by translocation of a large number of effector proteins by the SPI2 system . In this review, we summarize recent work on the cellular phenotypes related to SPI2 function and contribution of SPI2 effector proteins to these manipulations . These studies reveal a complex set of pathogenic interferences between intracellular Salmonella and its host cells.

Biol Trace Elem Res, 2004 Nov, 101(2), 147 - 63
Review on the role of dietary zinc in poultry nutrition, immunity, and reproduction; Park SY et al.; Zinc is an important nutrient in animal metabolism . In poultry, zinc serves not only as a nutrient but can also be used as a dietary supplement to manipulate the reproductive system of the bird . This article summarizes the general biochemistry, physiology, and nutritional aspects of zinc metabolism to provide a brief overview on what is known regarding zinc . The potential role of zinc in poultry immune response, Salmonella infection, and molting are emphasized.

Infect Immun, 2004 Dec, 72(12), 7357 - 9
Effect of inactivation of the HtrA-like serine protease DegQ on the virulence of Salmonella enterica serovar Typhimurium in mice; Farn J et al.; DegQ is a serine protease that is highly homologous to HtrA, an important virulence determinant of Salmonella enterica serovar Typhimurium . We examined if DegQ is involved in serovar Typhimurium pathogenesis . A serovar Typhimurium degQ mutant was as virulent as the wild-type strain in mice . However, a serovar Typhimurium htrA degQ mutant survived less well in murine organs, particularly in the liver, than a serovar Typhimurium htrA mutant . DegQ is not essential for serovar Typhimurium pathogenesis but may play a small role during salmonella growth at systemic sites.

Infect Immun, 2004 Dec, 72(12), 7338 - 41
Pigeon-associated strains of Salmonella enterica serovar Typhimurium phage type DT2 have genomic rearrangements at rRNA operons; Helm RA et al.; Strains from a subgroup of Salmonella enterica serovar Typhimurium frequently associated with pigeon infections were tested for genomic anomalies and virulence in mice . Some strains have a genomic inversion between rrn operons . Two prophages found in the common laboratory strain LT2 were absent . Pigeon-associated strains are still virulent in mice.

Infect Immun, 2004 Dec, 72(12), 7183 - 9
Synovial fibroblasts infected with Salmonella enterica serovar Typhimurium mediate osteoclast differentiation and activation; Zhang X et al.; The mechanisms whereby arthritogenic organisms may induce cartilage and bone erosions in infection-triggered arthritis remain unknown . In this study, we asked whether an arthritogenic organism could contribute to osteoclast differentiation and activation through regulation of the receptor activator of NF-kappaB ligand (RANKL) in synovial fibroblasts . Rat synovial fibroblasts were infected in vitro with Salmonella enterica serovar Typhimurium and monitored over time . The expression of RANKL in resting and infected synovial fibroblasts was quantified by reverse transcription-PCR and Western blotting . Osteoclast progenitors, isolated from femurs of 8-week-old rats and cultured in the presence of macrophage colony-stimulating factor, were cocultured with either infected or noninfected synovial fibroblasts for 2 to 4 days . Differentiation and maturation of osteoclasts were determined by morphology and tartrate-resistant acid phosphatase (TRAP) staining and by a bone resorption bioassay . RANKL expression was undetectable in resting synovial fibroblasts but was dose-dependently upregulated in cells after Salmonella infection . Osteoprotegerin was constitutively expressed by synovial fibroblasts and was not upregulated by infection . Further, we observed the formation of multinucleated TRAP-positive cells and formation of bone resorption pits in cocultures of bone marrow-derived osteoclast precursors with synovial fibroblasts infected with Salmonella but not with heat-killed Salmonella or noninfected cells . Arthritogenic bacteria may alter bone structure via synovial fibroblast intermediaries, since infected synovial fibroblasts (i) upregulate RANKL expression and (ii) enhance osteoclast precursor maturation into multinucleated, TRAP-positive, bone-resorbing, osteoclast-like cells . These data provide a link between infection and osteoclastogenesis . A better understanding of infection-mediated osteoclast differentiation and activation may provide new therapeutic strategies for inflammatory joint disease.

Infect Immun, 2004 Dec, 72(12), 7012 - 21
Oral vaccination of BALB/c mice with Salmonella enterica serovar Typhimurium expressing Pseudomonas aeruginosa O antigen promotes increased survival in an acute fatal pneumonia model; Digiandomenico A et al.; Pseudomonas aeruginosa is a leading cause of nosocomial pneumonia . We compared the efficacies of oral and intraperitoneal (i.p.) vaccinations of BALB/c mice with attenuated Salmonella enterica serovar Typhimurium SL3261 expressing P . aeruginosa serogroup O11 O antigen to protect against P . aeruginosa infection in an acute fatal pneumonia model . Oral and i.p . vaccines elicited O11-specific serum immunoglobulin G (IgG) antibodies, but IgA was observed only after oral immunization . Challenge of orally vaccinated mice with an O11 strain (9882-80) at 6 and 12 times the 50% lethal dose showed increased survival in mice that received the vaccine compared to phosphate-buffered saline (PBS)- and vector-treated controls; no difference in survival was seen with a heterologous strain, 6294 (serogroup O6) . In addition, significant protection against 9882-80 was not observed in i.p . vaccinated animals . Bronchoalveolar lavage fluid taken from immunized mice harbored O11-specific IgA and IgG in orally immunized mice but only modest levels of IgG in i.p . vaccinated mice . To correlate protection, opsonophagocytosis assays were performed with pooled sera from orally immunized animals . Efficient killing of five O11 clinical isolates was observed, while no killing was noted with 6294, indicating that the recombinant SL3261 oral vaccine induces an O11-specific reaction . We next determined the ability of orally vaccinated animals to clear bacteria from their lungs . Following P . aeruginosa challenge, the numbers of viable bacteria were significantly fewer in orally vaccinated animals than in PBS- and vector-treated controls . Our results suggest that oral immunization with recombinant SL3261 is efficacious in protection against pneumonia caused by P . aeruginosa.

Infect Immun, 2004 Dec, 72(12), 6987 - 93
Induction of cationic chicken liver-expressed antimicrobial peptide 2 in response to Salmonella enterica infection; Townes CL et al.; Cationic antimicrobial peptides constitute part of the innate immune system and provide an essential role in the defense against infection . At present there is a paucity of information regarding the antimicrobial profile of the chicken (Gallus gallus) . Using in silico studies, an expressed sequence tag (EST) clone was identified which encodes a novel cationic antimicrobial peptide, chicken liver-expressed antimicrobial peptide 2 (cLEAP-2) . The predicted amino acid sequence composed a prepropeptide, and the active peptide contained four conserved cysteine amino acids . The gene was localized to chromosome 13, and analysis of the genome revealed three exons separated by two introns . The cLEAP-2 gene was expressed in a number of chicken epithelial tissues including the small intestine, liver, lung, and kidney . Northern analysis identified liver-specific cLEAP-2 splice variants, suggesting some degree of tissue-specific regulation . To investigate whether cLEAP-2 expression was constitutive or induced in response to microbial infection, 4-day-old birds were orally infected with Salmonella . Analyses of cLEAP-2 expression by semiquantitative reverse transcription-PCR indicated that cLEAP-2 mRNA was upregulated significantly in the small intestinal tissues and the liver, indicative of direct and systemic responses . The antimicrobial activity of cLEAP-2 against Salmonella was analyzed in vitro with a time-kill assay and recombinant cLEAP-2 . Interestingly Salmonella enterica serovar Typhimurium SL1344 showed increased susceptibility to the active cationic peptide (amino acids 37 to 76) compared to S . enterica serovar Typhimurium C5 and Salmonella enteritidis . Taken together, these data suggest that cationic cLEAP-2 is part of the innate host defense mechanisms of the chicken.

Infect Immun, 2004 Dec, 72(12), 6860 - 9
Salmonella enterica serovar Typhimurium infection induces cyclooxygenase 2 expression in macrophages: involvement of Salmonella pathogenicity island 2; Uchiya K et al.; Salmonella pathogenicity island 2 (SPI-2) is required for intramacrophage survival and systemic infection in mice . We have recently reported that Salmonella enterica causes activation of the protein kinase A (PKA) signaling pathway in a manner dependent on SPI-2, resulting in the upregulation of interleukin-10 expression in macrophages (K . Uchiya et al., Infect . Immun . 72:1964-1973, 2004) . We show in the present study the involvement of SPI-2 in a signal transduction pathway that induces the expression of cyclooxygenase 2 (COX-2), an inducible enzyme involved in the synthesis of prostanoids . High levels of prostaglandin E(2) (PGE(2)) and prostacyclin (PGI(2)), which are known to activate the PKA signaling pathway via their receptors, were induced in J774 macrophages infected with wild-type Salmonella compared to a strain carrying a mutation in the spiC gene, located within SPI-2 . The increased production of both prostanoids was dependent on COX-2 . COX-2 expression was dose dependently blocked by treatment with a specific inhibitor of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway, and the phosphorylation level of ERK1/2 was higher in macrophages infected with wild-type Salmonella compared to the spiC mutant . Taken together, these results indicate that Salmonella causes an SPI-2-dependent ERK1/2 activation that leads to increased COX-2 expression, resulting in the upregulation of PGE(2) and PGI(2) production in macrophages . A COX-2 inhibitor inhibited not only Salmonella-induced activation of the PKA signaling pathway but also growth of wild-type Salmonella within macrophages, suggesting that Salmonella utilizes the COX-2 pathway to survive within macrophages and that the mechanism involves activation of the PKA signaling pathway.

Biochem Biophys Res Commun, 2004 Dec 24, 325(4), 1454 - 8
The microcin J25 beta-hairpin region is important for antibiotic uptake but not for RNA polymerase and respiration inhibition; Bellomio A et al.; The antibiotic microcin J25 (MccJ25) was cleaved by hydrolysis with thermolysin giving a two-chain peptide (MccJ25-Th19) of 10 and 9 amino acid residues . MccJ25-Th19 with deep modifications in beta-hairpin region had no effect on Escherichia coli growth, but still inhibited RNA polymerase in vitro and oxygen consumption in Salmonella strains . MccJ25-Th19 showed antibiotic activity on E . coli transformed with plasmids containing either fhuA or sbmA genes, which code for proteins involved in MccJ25 transport . These results suggest that an intact beta-hairpin region is crucial for MccJ25 import but not for inhibition of E . coli RNA polymerase or oxygen consumption in Salmonella strains.

Microbes Infect, 2004 Nov, 6(14), 1278 - 86
Salmonella carrier state in chicken: comparison of expression of immune response genes between susceptible and resistant animals; Sadeyen JR et al.; Asymptomatic Salmonella enterica serovar Enteritidis carrier state in poultry has serious consequences on food safety and public health due to the risks of food poisoning following consumption of contaminated products . An understanding the mechanisms of persistence of Salmonella in the digestive tract of chicken can be achieved by a better knowledge of the defects in the control of infection in susceptible versus resistant animals . The gene expression of innate immune response factors including anti-microbial molecules, inflammatory and anti-infectious cytokines was studied in the caecal lymphoid tissue associated with the carrier state . Expression levels of these genes were assessed by real-time PCR and were compared in two inbred lines of chickens differing in resistance to the carrier state following oral inoculation of S . enterica serovar Enteritidis at 1 week of age . No correlation was observed between resistance/susceptibility to caecal carrier state and level of interleukin (IL)-1beta, IL-8, IL-18, inducible NO synthase (iNOS) and natural resistance associated macrophage protein 1 (NRAMP1) . A high baseline level of defensin gene expression was recorded in young animals from the susceptible line . In contrast, a significantly low expression of interferon-gamma (IFN-gamma) gene was observed in these susceptible infected animals in comparison to resistant ones and healthy counterparts . IFN-gamma expression level represents a valuable indication of immunodeficiency associated with persistence of Salmonella in the chicken digestive tract, and IFN-gamma thus represents a factor to consider in the development of prophylactic measures for the reduction of Salmonella carrier state.

Mol Microbiol, 2004 Dec, 54(5), 1186 - 98
The related effector proteins SopD and SopD2 from Salmonella enterica serovar Typhimurium contribute to virulence during systemic infection of mice; Jiang X et al.; Salmonella resides within host cells in a vacuole that it modifies through the action of virulence proteins called effectors . Here we examined the role of two related effectors, SopD and SopD2, in Salmonella pathogenesis . Salmonella enterica serovar Typhimurium (S . Typhimurium) mutants lacking either sopD or sopD2 were attenuated for replication in the spleens of infected mice when competed against wild-type bacteria in mixed infection experiments . A double mutant lacking both effector genes did not display an additive attenuation of virulence in these experiments . The double mutant also competed equally with both of the single mutants . Deletion of either effector impaired bacterial replication in mouse macrophages but not human epithelial cells . Deletion of sopD2 impaired Salmonella's ability to form tubular membrane filaments {Salmonella-induced filaments (Sifs)} in infected cells; the number of Sifs decreased, whereas the number of pseudo-Sifs (thought to be a precursor of Sifs) was increased . Transfection of HeLa cells with the effector SifA induced the formation of Sif-like tubules and these were observed in greater size and number after co-transfection of SifA with SopD2 . In infected cells, SifA and SopD2 were localized both to Sifs and to pseudo-Sifs . In contrast, deletion of sopD had no effect on Sif formation . Our results indicate that both SopD and SopD2 contribute to virulence in mice and suggest a functional relationship between these two proteins during systemic infection of the host.

Zh Mikrobiol Epidemiol Immunobiol, 2004 Sep-Oct, (5), 101 - 3
{Comparative characterization of laboratory-made selective nutrient media for Salmonella accumulation}
{Spread of salmonellosis in Moscow and the ways of its prophylaxis}
{No authors listed}

The article deals with the results of the epidemiological analysis of the spread of salmonellosis in Moscow . During the last 15 years the proportion of Salmonella enteritidis was about 80% and more . After salmonellosis morbidity decreased to 19.9 per 100,000 of the population (the minimum level) in 1985 its sharp rise was noted . Morbidity rate increased from 31.7 in 1987 to 55.1 per 100,000 in 1988, then to 93.9 per 100,000 of the population in 1989 (the maximum level) . In the subsequent years up to 1996 a decrease in morbidity rate was observed, but in 1997-2002 morbidity rate stabilized within 29.8-35.7 per 100,000 of the population without a perceptible tendency towards decrease . The sharp increase of the etiological role of S . enteritidis which led to a wide spread of Salmonella infections was caused by the "chicken-egg" factor of their transmission . High morbidity rate among children and adults, registered all the year round, is the consequence of the constant epidemic activity of this factor.

Mikrobiol Z, 2004 Sep-Oct, 66(5), 57 - 61
{Mutagenic effect of synthetical fungicides and drugs of biological origin on microorganisms}; Residual feed intake and its effect on Salmonella enteritidis infection in growing layer hens; Adaptation Physiology Group, Animal Sciences Group, Wageningen University, 6700 AH Wageningen, The Netherlands . Ellen.vanEerden@wur.nl

Previous phenotypic selection on residual feed intake (RFI) identified 20 efficient R- chickens and 20 nonefficient R+ chickens . Residual feed intake was defined as the difference between observed feed intake (FI) and expected FI based on metabolic BW and BW gain, and was used as a measure for feed efficiency . Body weight and BW gain were similar for both groups . Feed intake and RFI were significantly higher in R+ birds . It is hypothesized that nonefficient R+ birds are more flexible to divert resources from production processes toward maintenance processes, thus being better capable of handling a bacterial challenge . Chickens of both groups were randomly allocated to immunization with heat-inactivated Salmonella enteritidis bacteria, or inoculation with live Salmonella bacteria . Transportation to the isolation units caused a decrease in FI in R+ birds . This may reflect a particular way of coping with stress in R+ birds . More R+ birds stopped bacterial shedding considering a nonshedding interval of 10 or 11 d (P = 0.041) . Nonantigen-specific antibody responses against keyhole limpet hemocyanin (KLH) were higher in R- birds . We conclude that R+ birds are able to keep their metabolism at a higher level, as indicated by higher heart and liver weights, and that Salmonella infection leads to reduced heart, liver, and gizzard weights . Oviduct weight and number of small yellow follicles were reduced in infected birds . Antigen-specific antibody responses were not different between the groups, indicating high priority for this parameter as a life trait . Possible differences in stress susceptibility between efficient and nonefficient chickens need further examination.

Poult Sci, 2004 Nov, 83(11), 1857 - 60
Utilization of the nitrate reductase enzymatic pathway to reduce enteric pathogens in chickens; McReynolds JL et al.; Previous reports have shown that some bacteria, including Salmonella, use a dissimilatory nitrate reductase enzyme pathway (NREP) in anaerobic environments . This enzyme reduces nitrate to nitrite and has been shown to cometabolize chlorate to cytotoxic chlorite . The present investigations were performed to evaluate the susceptibility of a competitive exclusion culture (CE) to the experimental chlorate product (ECP) . A commercially available CE product was evaluated for its nitrate reductase activity and therefore its chlorate sensitivity . Individual isolates (in triplicate) were cultured in 10 mL of Viande Levure broth containing 5 mM sodium nitrate or 10 mM sodium chlorate . Bacterial growth (optical density at 625 nm) was measured and 1-mL aliquots were removed concurrently for colorimetric determination of nitrate content at 0, 3, 6, and 24 h . Of the 15 different facultative strains, 11 had slight NREP utilization, 3 had moderate NREP utilization, and the remainder were NREP negative (with slight and moderate NREP utilization: >0.1 to <1.0 mM and >1.0 mM nitrate used within 6 h, respectively) . Of the obligate anaerobes evaluated, 3 had slight NREP utilization and the remainder were NREP negative . In vivo studies utilizing both products (CE and ECP) in a horizontal transmission challenge model (seeders + contacts) showed significant reductions in Salmonella from 5.37 to 1.76 log10 cfu/g and 3.94 to 0.07 log10 cfu/g, respectively . The combined effect of the CE culture and an ECP are effective in killing these food-borne pathogens.

J Food Prot, 2004 Nov, 67(11), 2608 - 12
Antibacterial effect of water-soluble tea extracts on foodborne pathogens in laboratory medium and in a food model; Kim S et al.; The microbial inhibition of foodborne pathogens was determined in brain heart infusion broth with 10% (wt/vol) water-soluble extracts of green, jasmine, black, dungglre, and oolong tea against Escherichia coli O157:H7, Salmonella enterica serovar Enteritidis, Listeria monocytogenes, and Staphylococcus aureus . The mixed culture (approximately 6.0 log CFU/ml), which was composed of the four pathogens, was inoculated into brain heart infusion broth with and without tea extracts . After incubation at 35 degrees C for 0, 1, 3, and 5 days, proper dilution of each sample was spiral plated on each selective agar . Viable cell counts were performed after incubation at 35 degrees C for 24 to 36 h . Green, jasmine, and black tea exhibited an approximately 5.0 log suppression of S . aureus compared with the control from days 1 to 5 . Green and jasmine tea also suppressed the growth of L . monocytogenes by approximately 3.0 log CFU/ml on day 5 . In contrast, no tea extracts inactivated E . coli O157:H7 and Salmonella Enteritidis . Based on the result in liquid medium, green and jasmine teas of 0.1% (vol/wt) were individually evaluated for their antimicrobial activity against L . monocytogenes and S . aureus in a food model (ground beef) stored at 7 degrees C for 0, 1, 3, 5, and 7 days . Viable cell counts of total bacteria, L . monocytogenes, and S . aureus in ground beef were not significantly different among green and jasmine tea and the control.

J Food Prot, 2004 Nov, 67(11), 2550 - 4
Spectroscopic quantification of bacteria using artificial neural networks; Gupta MJ et al.; Fourier transform-infrared spectroscopy, in conjunction with artificial neural networks, has been used for identification and classification of selected foodborne pathogens . Five bacterial species (Enterococcus faecium, Salmonella Enteritidis, Bacillus cereus, Yersinia enterocolitica, Shigella boydii) and five Escherichia coli strains (O103, O55, O121, O30, O26) suspended in phosphate-buffered saline were enumerated to provide seven different concentrations ranging from 10(9) to 10(3) CFU/ ml . The trained artificial neural networks were then validated with an independent subset of samples and compared with the traditional plate count method . It was found that the concentration-based classification of the species was 100% correct and the strain-based classification was 90 to 100% accurate.

J Food Prot, 2004 Nov, 67(11), 2416 - 23
Egg consumption patterns and Salmonella risk in Finland; Lievonen S et al.; To estimate the consumer risk of contracting Salmonella infection via shell eggs and to evaluate the effect of possible preventative measures, quantitative microbiological risk assessment is being developed in Finland . As a part of the risk assessment, a survey of 918 respondents was conducted to study how households purchase, store, handle, and use eggs . In addition, suitability of the Internet as a survey method was compared with a postal survey . Shell eggs were usually purchased once every 2 weeks (41% of all the respondents) . Ninety-one percent of the respondents bought eggs in groceries and 93% stored eggs at chilled temperatures . The majority of the respondents (80%) only had eggs in their home for which the best-before date had not expired . Only 34% of the respondents said that they always washed their hands after breaking eggs . Consumption of well-cooked eggs accounted for 84%, consumption of soft-boiled eggs for 12%, and consumption of raw eggs for 4% of the total amount of eggs consumed . The elderly used eggs more frequently than the whole population, but the consumption of raw egg dishes decreased with age . The Internet survey was a rapid method for transmitting information, but its response rate was low (9%), and it did not appear to be a suitable tool for data collection in a general population . The results indicate that although the majority of the respondents had safe egg-handling practices, a substantial minority of the consumers had risk-prone behavior.

J Food Prot, 2004 Nov, 67(11), 2381 - 6
Survival of Escherichia coli O157:H7 and Salmonella in apple cider and orange juice as affected by ozone and treatment temperature; Williams RC et al.; Inactivation of Escherichia coli O157:H7 and Salmonella in apple cider and orange juice treated with ozone was evaluated . A five-strain mixture of E . coli O157:H7 or a five-serovar mixture of Salmonella was inoculated (7 log CFU/ml) into apple cider and orange juice . Ozone (0.9 g/h) was pumped into juices maintained at 4 degrees C, ambient temperature (approximately 20 degrees C), and 50 degrees C for up to 240 min, depending on organism, juice, and treatment temperature . Samples were withdrawn, diluted in 0.1% peptone water, and surface plated onto recovery media . Recovery of E . coli O157:H7 was compared on tryptic soy agar (TSA), sorbitol MacConkey agar, hemorrhagic coli agar, and modified eosin methylene blue agar; recovery of Salmonella was compared on TSA, bismuth sulfite agar, and xylose lysine tergitol 4 (XLT4) agar . After treatment at 50 degrees C, E . coli O157:H7 populations were undetectable (limit of 1.0 log CFU/ml; a minimum 6.0-log CFU/ml reduction) after 45 min in apple cider and 75 min in orange juice . At 50 degrees C, Salmonella was reduced by 4.8 log CFU/ml (apple cider) and was undetectable in orange juice after 15 min . E . coli O157:H7 at 4 degrees C was reduced by 4.8 log CFU/ml in apple cider and by 5.4 log CFU/ml in orange juice . Salmonella was reduced by 4.5 log CFU/ml (apple cider) and 4.2 log CFU/ml (orange juice) at 4 degrees C . Treatment at ambient temperature resulted in population reductions of less than 5.0 log CFU/ml . Recovery of E . coli O157:H7 and Salmonella on selective media was substantially lower than recovery on TSA, indicating development of sublethal injury . Ozone treatment of apple cider and orange juice at 4 degrees C or in combination with mild heating (50 degrees C) may provide an alternative to thermal pasteurization for reduction of E . coli O157:H7 and Salmonella in apple cider and orange juice.

Water Sci Technol, 2004, 50(7), 53 - 60
Hygienization of municipal sludge in automatically operated chamber filter presses with thermal vacuum drying; Sagberg P; This paper presents the state of the art of thermal vacuum drying in chamber filter presses for unattended automatic operation . The achieved results are exemplified by the treatment of the two stage digested combined primary, chemical and biological sludge created by the VEAS concept for nutrient removal from municipal wastewater at VEAS . The water removal rate in each stage of the drying process is described, with comments on the low energy needs . The advantages of one-sided heating, the capacity and the drying potential are discussed . The hygienization potential of the process is demonstrated by the effect on thermostable coliform bacteria, Escherichia coli, salmonella, the spores of sulfite reducing anaerobic bacteria, f-specific bacteriophages, the seeds of the weed, wild oat, Avena fatua, and the parasite eggs of the potato cyst nematode, Globodera rostochiensis . A more complete paper with the VEAS-concept is found on the VEAS homepage .

Mutagenesis, 2004 Nov, 19(6), 445 - 51
Determination of sediment mutagenicity and cytotoxicity in an area subjected to petrochemical contamination; Horn RC et al.; This study is an evaluation of the mutagenic and cytotoxic activity of sediments in Bom Jardim stream, one of the tributaries of the Cai River basin, Rio Grande do Sul, Brazil . This stream receives an indirect contribution of treated effluent from a petrochemical plant . The Salmonella/microsome assay, a microsuspension method, was used to evaluate moderately polar extracts of sediment samples at three points along the stream . The grain size analysis showed a lower mean content of fine particles in the principle face (front) of the complex, and this was also the sampling point with the lowest percentage of extracted organics . Low mutagenic activity was observed at the different sites studied, ranging from 3.3 to 8.3%; cytotoxic activity was more important in this area, ranging from 20 to 40%, adding up the results of assays in the presence and absence of external metabolism . In assays without S9mix there were more frequent mutagenic and cytotoxic responses, with frameshift mutations being the most frequent . The results also showed that there was a gradual, seasonal distribution of the responses as the stream mouth is reached, the most compromised points being in front of and downstream of the complex . Mutagenic and cytotoxic activity in sediment samples has proved important to determine environmental quality, despite the complexity of the chemical composition of the environmental matrix . Furthermore, use of the Salmonella assay to monitor mutagenesis and cytotoxicity helped identify the presence of pollutants . This assay is an important tool, aimed mainly at actions to preserve the genetic heritage of the fauna and flora affected by human activity and to improve environmental quality.

Lett Appl Microbiol, 2004, 39(6), 509 - 15
Evaluation of two real-time polymerase chain reaction pathogen detection kits for Salmonella spp . in food; Cheung PY et al.; AIMS: To evaluate the LightCycler Salmonella Detection Kit and the TaqMan Salmonella Gold Detection and Quantitation Kit for the real-time PCR detection of Salmonella in various food samples . METHODS AND RESULTS: Ready-to-eat foods and raw food samples were artificially contaminated with Salmonella serotypes . In the specificity test, bacterial DNA extracted from sample pre-enrichment culture was analysed with the detection kits performed respectively on the LightCycler Instrument or the ABI Prism 7000 Sequence Detection System . No false-positive or false-negative results were obtained, although the LightCycler system generated invalid PCR results on two occasions . In the sensitivity test using the LightCycler system, Salmonella could be detected in pre-enrichment cultures of 25-g samples inoculated with as low as 1.5 x 10(3) CFU (depending on food type), and false-negative results were obtained for samples with low inoculum levels . CONCLUSIONS: Two commercial kits for real-time PCR detection of Salmonella were evaluated . SIGNIFICANCE AND IMPACT OF THE STUDY: Evaluation using more food types and matrices, and foods that contain low number of Salmonella or high number of other competing bacteria, is needed before adopting the real-time PCR technique for routine food tests.

Angiology, 2004 Nov-Dec, 55(6), 701 - 5
Salmonella aortic aneurysm: suggestions for diagnosis and therapy based on personal experience--a case report; Cicconi V et al.; Infectious aneurysm is a rare event, especially after the introduction of antibiotic therapy . However, its early detection is very important for timely treatment with antibiotics and surgical intervention . This pathology may generally be due to mycotic endocarditis or septic embolization, prevailing in the preantibiotic era, and to aortitis, whose incidence is actually increasing, mainly in subjects with preexisting large-vessel atherosclerosis and intimal defects . This clinical entity is usually defined as microbial arteritis and recognizes Salmonella spp as the microorganism most frequently isolated from blood or vascular tissue cultures . The authors present the case of a 56-year-old man with a history of hypertension that some weeks before admission manifested as hyperpyrexia and episodic lumbar pain, associated with hepatosplenomegaly and with a pulsing mass in the periumbilical region . Abdominal computed tomography (CT) scan documented a voluminous infrarenal aortic aneurysm with a markedly reduced and irregular vessel wall . The patient underwent surgical excision of the aneurysm, during which marked periaortic inflammation phenomena, complete absence of the posterior aortic wall for a length of 5-6 cm, and the exposure of the correspondent vertebral bodies were observed . Histopathologic examination of the aneurysmal tissue showed atheromatous and thrombotic aspects and confirmed strong signs of inflammation . This case may suggest that the occurrence of microbial aortitis, especially from Salmonella spp, should be taken into account in the presence of a septic status associated with back, abdominal, or thoracic pain.

J Bacteriol, 2004 Dec, 186(23), 7881 - 7
Purification and initial characterization of the Salmonella enterica PduO ATP:Cob(I)alamin adenosyltransferase; Johnson CL et al.; The PduO enzyme of Salmonella enterica is an ATP:cob(I)alamin adenosyltransferase that catalyzes the final step in the conversion of vitamin B(12) to coenzyme B(12) . The primary physiological role of this enzyme is to support coenzyme B(12)-dependent 1,2-propanediol degradation, and bioinformatic analysis has indicated that it has two domains . Here the PduO adenosyltransferase was produced in Escherichia coli, solubilized from inclusion bodies, purified to apparent homogeneity, and partially characterized biochemically . The K(m) values of PduO for ATP and cob(I)alamin were 19.8 and 4.5 microM, respectively, and the enzyme V(max) was 243 nmol min(-1) mg of protein(-1) . Further investigations showed that PduO was active with ATP and partially active with deoxy-ATP, but lacked measurable activity with other nucleotides . (31)P nuclear magnetic resonance established that triphosphate was a product of the PduO reaction, and kinetic studies indicated a ternary complex mechanism . A series of truncated versions of the PduO protein were produced in Escherichia coli, partially purified, and used to show that adenosyltransferase activity is associated with the N-terminal domain . The N-terminal domain was purified to near homogeneity and shown to have biochemical properties and kinetic constants similar to those of the full-length enzyme . This indicated that the C-terminal domain was not directly involved in catalysis or substrate binding and may have another role.

J Pharmacol Exp Ther . 2004 Nov 16; {Epub ahead of print}
Cyclooxygenase-2 inhibition improves vascular endothelial dysfunction in a rat model of endotoxic shock: role of iNOS and oxidative stress; Virdis A et al.; We investigated whether cyclooxygenase isoforms (COX-1, COX-2) and decreased NO availability contribute to endothelial dysfunction in endotoxemic rats . The involvement of ROS was also evaluated . Rats were injected with Salmonella-derived lipopolysaccharide or saline . After 6 hours, endothelial function of mesenteric resistance arteries was evaluated . In controls, ACh-induced relaxation was inhibited by the NOS inhibitor L-NMMA and unaffected by DFU (COX-2 inhibitor) . In LPS-treated rats, the response to ACh was blunted compared with controls, less sensitive to L-NMMA and enhanced by DFU . COX-2 blockade improved also the inhibitory effect of L-NMMA on cholinergic relaxation . SC-560 (COX-1 inhibitor) did not modify the response to ACh in both groups . LPS-induced endothelial dysfunction was unaffected by the TxA2 receptor antagonist SQ-29548 . In vivo iNOS inhibition by S-methylisothiourea partly attenuated LPS-induced endothelial dysfunction . The antioxidants ascorbic acid and SOD normalized endothelium-dependent relaxation and restored the inhibitory action of L-NMMA on ACh . Responses to sodium nitroprusside were similar in both groups . In LPS-treated rats, RT-PCR showed a marked increase in mesenteric iNOS and COX-2 expressions, while eNOS and COX-1 were unchanged . LPS-induced COX-2 overexpression was reduced but not abrogated by S-methylisothiourea . LPS-induced COX-2 upregulation was also documented by immunohistochemistry . In conclusion, mesenteric resistance vessels from endotoxemic rats show impaired endothelial function due to reduced NO availability, a condition which is partly ascribable to an iNOS-dependent enhanced COX-2 expression, whereas TxA2 does not seem to be involved . Oxidative stress is the main mechanism responsible for reduced NO availability and COX-2 might act as a source of ROS.

Intern Med J, 2004 Nov, 34(11), 641 - 5
Five cases of non-typhoidal Salmonella endovascular infection; Drinkovic D et al.; The incidence of human non-typhoidal Salmonella (NTS) infection has increased in many countries . Endovascular infection is one of the most serious forms of extraintestinal infection . Five patients with NTS endovascular infection treated at Middlemore Hospital, Auckland, New Zealand, are presented here . All persons with NTS bacteraemia who are older than 50 years and have a risk of atherosclerosis should be evaluated for possible endovascular infection.

J Appl Microbiol, 2004, 97(6), 1115 - 22
Direct detection of bacterial pathogens in representative dairy products using a combined bacterial concentration-PCR approach; Stevens KA et al.; AIMS: To develop a simple, rapid method to concentrate and purify bacteria and their nucleic acids from complex dairy food matrices in preparation for direct pathogen detection using polymerase chain reaction (PCR) . METHODS AND RESULTS: Plain non-fat yogurt and cheddar cheese were each seeded with Listeria monocytogenes or Salmonella enterica serovar . Enteritidis in the range of 10(1)-10(6) CFU per 11-g sample . Samples were then processed for bacterial concentration using high-speed centrifugation (9700 g) followed by DNA extraction, PCR amplification, and amplicon confirmation by hybridization . Bacterial recoveries after centrifugation ranged from 53 to >100% and 71 to >100% for serovar . Enteritidis and L . monocytogenes, respectively, in the non-fat yogurt samples; and from 77 to >100% and 69 to >100% for serovar . Enteritidis and L . monocytogenes, respectively, in the cheddar cheese samples . There were no significant differences in recovery efficiency at different inocula levels, and losses to discarded supernatants were always <5%, regardless of dairy product or pathogen . CONCLUSIONS: When followed by pathogen detection using PCR and confirmation by amplicon hybridization, detection limits of 10(3) and 10(1) CFU per 11-g sample were achieved for L . monocytogenes and serovar . Enteritidis, respectively, in both product types and without prior cultural enrichment . SIGNIFICANCE AND IMPACT OF THE STUDY: This study represents progress toward the rapid and efficient direct detection of pathogens from complex food matrices at detection limits approaching those that might be anticipated in naturally contaminated products.

Med Dosw Mikrobiol, 2004, 56(2), 187 - 98
{Interaction of neomycin and the other antibiotic on selected bacterial strains}; Grzybowska W et al.; Antimicrobial combinations are used most frequently to provide broad-spectrum empirical coverage in the treatment of bacterial infections . However, combination of two antibiotics may not influence their activity, may lead to synergy or antagonism in the activity . Neomycin may be combined with one of the following antibiotics: ampicillin, procaine penicillin, gramicidin, bacitracin, polymyxin B, lincomycin, oxytetracycline, and erythromycin in some human and veterinary multiantibiotic drugs distributed in Poland . The checkerboard method has been one of the traditional assays for the measurement of antibiotic interactions . The aim of this study was to analyse the activity interaction of neomycin with second antibiotic in multiantibiotic drugs distributed in Poland on standards and clinical bacterial strains . Checkerboard results for all strains demonstrated synergism for 2.5% of combinations, only for standards strains . In one case Salmonella Enteritidis, in combination of neomycin with bacitracin, inhibition effect was observed . Additive effects were predominant--49% . In 18% neutral effects were shown, but in 26% of combinations FIC indexes were not possible to calculate, because of the resistance of clinical strains to the highest concentration of at least one antibiotic . In combination of aminoglycoside (neomycin) with beta-lactams antibiotics (ampicillin, procaine penicillin) in vitro, no synergy was observed for all examined strains . The best results were achieved for combinations of neomycin with peptide antibiotics (polymyxin, gramicidin and bacytracin)--5 for all 6 synergy effect observed.

Mem Inst Oswaldo Cruz, 2004 Aug, 99(5), 477 - 80 Epub 2004 Nov 03.
Monitoring of the dissemination of Salmonella in the chicken Frankfurt-sausage production line of a sausage factory in the state of São Paulo, Brazil; Luiz Ade F et al.; Poultry meat and its derivatives are among the foodstuffs considered by environmental health authorities to present the highest risks to the public . A total of 185 samples were collected in five monthly batches, from different processing stages in a sausage plant that uses mechanically-deboned chicken meat (MDCM), and tested for the presence of Salmonella . Enrichment was carried out in both Kauffman's tetrathionate broth and Rappaport-Vassiliadis broth and isolation on Salmonella-Shigella agar and brilliant-green agar . Live Salmonella bacteria were isolated from six samples of the raw meat and from the emulsion, in batches three, four, and five, but not from any sample in batches one or two . The six isolated strains were all classified as Salmonella Albany, which has not previously been reported in MDCM . Of the two enrichment broths, Rappaport-Vassiliadis gave the better results . The pattern of contamination suggests a probable common source, given that a new supplier was used in the third, fourth, and fifth months . It was also shown that the industrial cooking was effective in preventing Salmonella surviving in the final product.

J Virol, 2004 Dec, 78(23), 12901 - 9
Improved efficiency of a Salmonella-based vaccine against human papillomavirus type 16 virus-like particles achieved by using a codon-optimized version of L1; Baud D et al.; Cervical cancer results from cervical infection by human papillomaviruses (HPVs), especially HPV16 . An effective vaccine against these HPVs is expected to have a dramatic impact on the incidence of this cancer and its precursor lesions . The leading candidate, a subunit prophylactic HPV virus-like particle (VLP) vaccine, can protect women from HPV infection . An alternative improved vaccine that avoids parenteral injection, that is efficient with a single dose, and that induces mucosal immunity might greatly facilitate vaccine implementation in different settings . In this study, we have constructed a new generation of recombinant Salmonella organisms that assemble HPV16 VLPs and induce high titers of neutralizing antibodies in mice after a single nasal or oral immunization with live bacteria . This was achieved through the expression of a HPV16 L1 capsid gene whose codon usage was optimized to fit with the most frequently used codons in Salmonella . Interestingly, the high immunogenicity of the new recombinant bacteria did not correlate with an increased expression of L1 VLPs but with a greater stability of the L1-expressing plasmid in vitro and in vivo in absence of antibiotic selection . Anti-HPV16 humoral and neutralizing responses were also observed with different Salmonella enterica serovar Typhimurium strains whose attenuating deletions have already been shown to be safe after oral vaccination of humans . Thus, our findings are a promising improvement toward a vaccine strain that could be tested in human volunteers.

Eur Cytokine Netw, 2004 Jul-Sep, 15(3), 203 - 9
PADMA-28, a Tibetan herbal preparation is an inhibitor of inflammatory cytokine production; Barak V et al.; BACKGROUND: Previous studies have shown that PADMA-28, a multicomponent, traditional Tibetan herbal plant preparation possesses a variety of beneficial effects on several experimental models of inflammatory and immune processes, including autoimmune diabetes and autoimmune encephalomyelitis . In humans, PADMA-28 attenuated the symptoms associated with intermittent claudications in atherosclerotic patients . OBJECTIVE: To assess the effect of PADMA 28 on the immune system, e.g . cytokine (interleukins) production . DESIGN: Cytokine production by human blood monocytes (derived from 12 healthy donors) stimulated in vitro, either by endotoxin (LPS) from Salmonella typhi or by lipoteichoic acid (LTA) from group A Streptococci was modulated by PADMA-28 . RESULTS: The present study showed that an aqueous extract of PADMA-28 strongly decreased the production of the inflammatory cytokines IL-1beta, IL-6, IL-8 and TNF-alpha, and more moderately, also decreased the anti-inflammatory cytokine IL-10 induced by LPS . However, the LTA - induced IL-10 production was {not significantly} increased by the low dose PADMA-28, while not effected at all by the higher dose of PADMA-28 . CONCLUSIONS: The data from these finding suggest a possible clinical efficacy of PADMA-28 either in autoimmune and in inflammatory conditions or in post-inflammatory sequelae, as previously shown in in vivo and human studies, probably by decreasing inflammatory cytokines.

Mutat Res, 2004 Dec 21, 568(2), 211 - 20
Induction of A:T to G:C transition mutations by 5-(2-chloroethyl)-2'-deoxyuridine (CEDU), an antiviral pyrimidine nucleoside analogue, in the bone marrow of Mutatrade markMouse; Staedtler F et al.; 5-(2-Chloroethyl)-2'-deoxyuridine (CEDU) is a pyrimidine nucleoside analogue formerly in development for the treatment of herpes simplex virus infections . The compound proved clearly mutagenic in the mouse spot test and exhibited weak activity in the Salmonella reverse mutation test, which led to the termination of the compound's development . In another study, CEDU, administered orally to beta-galactosidase (lacZ) transgenic mice (Mutatrade markMouse) for five days, induced a clear increase in lacZ mutant frequencies in spleen, lung, and bone marrow . In the present follow-up study, we analyzed 32 of those lacZ mutants isolated from the bone marrow of the Mutatrade markMouse animals of the experiments mentioned above, in order to obtain further information on the type of mutations induced by CEDU . CEDU induced a pronounced increase in A:T to G:C transitions . The distribution of A:T to G:C transitions was clearly non-random, showing a bias towards T to C substitutions in the coding DNA strand and a preference to occur in the sequence motif 5'-(G or C)-T-G-3' . Our data support the hypothesis that CEDU, after being phosphorylated, is incorporated into cellular DNA in place of thymidine, which leads to mispairing with guanosine during subsequent DNA replication . As a result, the compound is thought to exert its mutagenicity by inducing mismatches leading to T to C transitions . Our findings point towards a mode of mutagenic action of CEDU that differs fundamentally from that of other antiviral antinucleosides whose clastogenic and recombinogenic activities prevail.

Mutat Res, 2004 Dec 21, 568(2), 195 - 209
Induction of gene mutations by 5-(2-chloroethyl)-2'-deoxyuridine (CEDU), an antiviral pyrimidine nucleoside analogue; Suter W et al.; 5-(2-Chloroethyl)-2'-deoxyuridine (CEDU) had been developed for the treatment of herpes simplex infections . In the Salmonella reverse mutation test, the compound was found to be mutagenic in strains TA1535 and TA102 at very high concentrations (>/=2500mug/plate), both with and without S9-mix . The mutagenic potential of CEDU was further investigated in vivo and in vitro . It did not induce DNA repair in rat hepatocyte primary cultures, and was negative in the micronucleus test in V79 cells and in the comet assay in human leukocytes . In vivo, CEDU was negative in the bone marrow micronucleus test in CD1 mice . The mouse spot test provided a clearly positive result . Treatment of mice on day 9 of pregnancy with 2000mg/kg resulted in 5.9% of the F1 animals having genetically relevant spots, whereas the corresponding vehicle control group had a spot rate of 1.9% . Since these data clearly identified CEDU as an inducer of gene mutations in vivo, this potential was further investigated in lacZ transgenic Mutatrade markMouse . Six female animals were treated daily on five consecutive days with 2000mg/kg/day and sacrificed, after a treatment-free sampling time, 14 days later . The data showed a clear increase in the mutant frequency in the bone marrow, the lung and in the spleen . CEDU is an exception in the group of nucleoside analogues, because it was found to be a strong gene mutagen and, in contrast to the other compounds of this group investigated so far, had no considerable clastogenic effects.

BMC Infect Dis . 2004 Nov 15;4(1):48.
Molecular and epidemiologic analysis of a county-wide outbreak caused by Salmonella enterica subsp . enterica serovar Enteritidis traced to a bakery; Lu PL et al.; BACKGROUND: An increase in the number of attendees due to acute gastroenteritis and fever was noted at one hospital emergency room in Taiwan over a seven-day period from July to August, 2001 . Molecular and epidemiological surveys were performed to trace the possible source of infection . METHODS: An epidemiological investigation was undertaken to determine the cause of the outbreak . Stool and blood samples were collected according to standard protocols per Center for Disease Control, Taiwan . Typing of the Salmonella isolates from stool, blood, and food samples was performed with serotyping, antibiotypes, and pulsed field gel electrophoresis (PFGE) following XbaI restriction enzyme digestion . RESULTS: Comparison of the number of patients with and without acute gastroenteritis (506 and 4467, respectively) during the six weeks before the outbreak week revealed a significant increase in the number of patients during the outbreak week (162 and 942, respectively) (relative risk (RR): 1.44, 95% confidence interval (CI): 1.22-1.70, P value < 0.001) . During the week of the outbreak, 34 of 162 patients with gastroenteritis were positive for Salmonella, and 28 of these 34 cases reported eating the same kind of bread . In total, 28 of 34 patients who ate this bread were positive for salmonella compared to only 6 of 128 people who did not eat this bread (RR: 17.6, 95%CI 7.9-39.0, P < 0.001) . These breads were produced by the same bakery and were distributed to six different traditional Chinese markets., Salmonella enterica subsp . enterica serovar Enteritidis (S . Enteritidis) was isolated from the stool samples of 28 of 32 individuals and from a recalled bread sample . All S . Enteritidis isolates were of the same antibiogram . PFGE typing revealed that all except two of the clinical isolates and the bread isolates were of the same DNA macrorestriction pattern . CONCLUSIONS: The egg-covered bread contaminated with S . Enteritidis was confirmed as the vehicle of infection . Alertness in the emergency room, surveillance by the microbiology laboratory, prompt and thorough investigation to trace the source of outbreaks, and institution of appropriate control measures provide effective control of community outbreaks.

Mol Nutr Food Res, 2004 Dec, 48(7), 496 - 503
Expression profiles of effector proteins SopB, SopD1, SopE1, and AvrA differ with systemic, enteric, and epidemic strains of Salmonella enterica; Streckel W et al.; The presence and expression of sopB, sopD1, sopE1, and avrA genes encoding virulence associated effector proteins were studied comparatively in 405 Salmonella enterica strains . They belong to different serovars and clonal types (genotypes, phage types) and originated from different clinical (systemic infection, focal enteritis, enterocolitis) and epidemic sources (epidemics, sporadic cases) . The sopB and sopD1 determinants were commonly prevalent, but sopE1 and avrA genes only in 55% and 80%, respectively . A correlation of this pattern of absence and presence of the respective genes to the epidemic and clinical origin could not be detected . In contrast, the expression of the respective genes appeared differently: SopB and SopE1 proteins are well produced, but SopD1 and AvrA proteins only rarely under the applied standard culture conditions . However, using a range of different environmental signals (temperature, pH, cations, etc.) some of the S . enterica nonproducer strains (e . g., S . Agona, S . Bovismorbificans, S . Virchow, etc.) begin to produce AvrA and SopD1 . They turned now into an expression profile which was found typically for the epidemic strains of S . Typhimurium and S . Enteritidis . Also S . enterica strains from systemic infections could be characterized by their strong SopB and SopE1 expression while SopD1 and AvrA proteins were missing . Although it is premature to outline generally a correlation of these expression profiles and the clinical and epidemiological potency of Salmonellae, the reported results allow a first understanding how a fine tuning of their virulence will take place.

J Agric Food Chem, 2004 Nov 17, 52(23), 7180 - 6
Simultaneous and sensitive detection of three foodborne pathogens by multiplex PCR, capillary gel electrophoresis, and laser-induced fluorescence; Alarcon B et al.; The simultaneous detection of Staphylococcus aureus, Listeria monocytogenes, and Salmonella spp . has been approached by a new multiplex PCR-based procedure followed by capillary gel electrophoresis with laser-induced fluorescence detection (multiplex-PCR-CGE-LIF) . As compared to slab gel electrophoresis, the use of CGE-LIF improved from 10- to 1000-fold the sensitivity of the multiplex PCR analysis, allowing the detection of 2.6 x 10(3) cfu mL(-1) of S . aureus, 570 cfu mL(-1) of L . monocytogenes, and 790 cfu mL(-1) of Salmonella in artificially inoculated food, without enrichment . Following 6 h of enrichment, as low as 260, 79, and 57 cfu mL(-1) of S . aureus, L . monocytogenes, and Salmonella, respectively, were detected . The CGE-LIF method is shown to be reproducible, providing relative standard deviation (RSD) values lower than 0.8% for analysis time and lower than 5.8% for peak areas . The multiplex-PCR-CGE-LIF proved a powerful analytical tool to detect various food pathogens simultaneously in a fast, reproducible, and sensitive way.

Int J Med Microbiol, 2004 Oct, 294(5), 319 - 35
Bacteria as DNA vaccine carriers for genetic immunization; Schoen C et al.; Genetic immunization with plasmid DNA vaccines has proven to be a promising tool in conferring protective immunity in various experimental animal models of infectious diseases or tumors . Recent research focuses on the use of bacteria, in particular enteroinvasive species, as effective carriers for DNA vaccines . Attenuated strains of Shigella flexneri, Salmonella spp., Yersinia enterocolitica or Listeria monocytogenes have shown to be attractive candidates to target DNA vaccines to immunological inductive sites at mucosal surfaces . This review summarizes recent progress in bacteria-mediated delivery of plasmid DNA vaccines in the field of infectious diseases and cancer.

Int J Med Microbiol, 2004 Oct, 294(4), 225 - 33
Cell tropism of Salmonella enterica; Santos RL et al.; Salmonella serotypes are able to actively cross the intestinal epithelium, mainly but not exclusively through M cells in the follicle-associated epithelium of Peyer's patches . Once reaching the basal side of the epithelium, Salmonella serotypes are internalized by macrophages, dendritic cells, and neutrophils but are not found in fibroblasts or other mesenchymal cells . The outcome of the interaction between Salmonella serotypes and dendritic cells or neutrophils is detrimental to the pathogen . In some host species Salmonella serotypes find a safe haven from humoral defenses and neutrophils within macrophages, and replication within this niche appears to be a prerequisite for the development of a systemic infection . In other host species, macrophages can control bacterial growth and the infection remains localized to the intestine and mesenteric lymph nodes . This review summarizes our knowledge on the cellular tropism of Salmonella serotypes and the bacterial and host factors relevant for these interactions.

Nat Genet, 2004 Dec, 36(12), 1268 - 74 Epub 2004 Dec.
Comparison of genome degradation in Paratyphi A and Typhi, human-restricted serovars of Salmonella enterica that cause typhoid; McClelland M et al.; Salmonella enterica serovars often have a broad host range, and some cause both gastrointestinal and systemic disease . But the serovars Paratyphi A and Typhi are restricted to humans and cause only systemic disease . It has been estimated that Typhi arose in the last few thousand years . The sequence and microarray analysis of the Paratyphi A genome indicates that it is similar to the Typhi genome but suggests that it has a more recent evolutionary origin . Both genomes have independently accumulated many pseudogenes among their approximately 4,400 protein coding sequences: 173 in Paratyphi A and approximately 210 in Typhi . The recent convergence of these two similar genomes on a similar phenotype is subtly reflected in their genotypes: only 30 genes are degraded in both serovars . Nevertheless, these 30 genes include three known to be important in gastroenteritis, which does not occur in these serovars, and four for Salmonella-translocated effectors, which are normally secreted into host cells to subvert host functions . Loss of function also occurs by mutation in different genes in the same pathway (e.g., in chemotaxis and in the production of fimbriae).

Vet Microbiol, 2004 Nov 30, 104(1-2), 133 - 9
High prevalence of multiple resistance to antibiotics in Salmonella serovars isolated from a poultry slaughterhouse in Spain; Carraminana JJ et al.; Salmonellosis is a major foodborne infection in Spain, and strains that are resistant to a great variety of antibiotics have become a major public health concern . The aim of this study was to determine the level of antibiotic resistance in 133 Salmonella isolates obtained from a poultry slaughterhouse in Zaragoza (NE Spain) . Antimicrobial resistance testing was performed by disk diffusion method using 19 antibiotics . Results were interpreted following the NCCLS criteria . Overall, the highest percentage of resistance was found to the following antimicrobial agents: sulfadiazine (96.2%), neomycin (53.4%), tetracycline (21.8%), and streptomycin (11.3%) . All isolates were found to be resistant to one or more of the antibiotics tested . Multiple resistance was observed in 87 strains (65.4%) . We found 23 different patterns of resistance in Salmonella Enteritidis . Resistance to sulfadiazine was the most common single resistance . The most frequent patterns of multiresistant strains were neomycin+sulfadiazine and neomycin+tetracycline+sulfadiazine . S . 4,5,12:b: showed the highest percentages of resistance to the tested drugs, with five different resistance patterns found . Ampicillin+chloramphenicol+streptomycin+sulphonamides+tetracycline (ACSSuT) resistance pattern, commonly associated with S . Typhimurium DT 104, was not detected in strains of the same phage type from broilers . The appearance of substantial multiresistance in foodborne Salmonella isolates suggests the need for more prudent use of antibiotics by farmers, veterinarians, and physicians.

Avian Dis, 2004 Sep, 48(3), 706 - 10
Hexamita meleagridis (Spironucleus meleagridis) infection in chukar partridges associated with high mortality and intracellular trophozoites; Cooper GL et al.; An outbreak of infectious catarrhal enteritis, associated with the flagellated protozoan Spironucleus meleagridis (syn . Hexamita meleagridis), is reported from a commercial flock of chukar partridges in California . The disease affected birds between the ages of 4 and 6 wk and resulted in diarrhea, listlessness, depression, and high mortality . Concurrent infection with other intestinal pathogens, including Cryptosporidia, group E Salmonella, long-segmented filamentous microorganisms (LSFMOs), and Rotavirus-like virus particles, was found in some but not all affected birds . Dermatitis of the face, shanks, and feet, suggestive of B-complex vitamin deficiency, was present in most affected birds as well . Flagellated protozoan parasites could be found in the lumen of the duodenum and jejunum and in the intestinal crypts . In some cases the flagellates were wedged between epithelial cells or were located intracellularly within cells of the mucosal epithelium and the intestinal lamina propria.

Avian Dis, 2004 Sep, 48(3), 590 - 4
The occurrence and distribution of Salmonella enteritidis and other serovars on California egg laying premises: a comparison of two sampling methods and two culturing techniques; Kinde H et al.; Between the summer of 1998 and the winter of 2000, Salmonella analysis was performed on 2128 single and 532 pooled manure drag swabs obtained from 133 California commercial egg laying farms . The isolation of Salmonella from all rows and from all flocks using single or pooled swabs was 80% and 92%, respectively . Hence, there was no statistical difference between single vs . pooled swabs in terms of identifying Salmonella on a row or flock basis . A total of 14 serogroups comprising 44 serotypes were isolated from 123 of 133 farms . When the top 10 serotypes were considered, there was no significant difference in the range of serotypes isolated by the two culturing methods . The overall S . enteritidis prevalence for California flocks was 10.5% (14/133) . The overall row prevalence for S . enteritidis for all the farms was 1.1% (24/2128), and the overall pool prevalence was 2.4% (13/532) . Sixty percent (12/20) of the S . enteritidis isolates from the positive farms were phage type 4, and 40% (8/20) represented five other phage types (1, 6B, 7, 8, and 28).

Avian Dis, 2004 Sep, 48(3), 550 - 61
Descriptive study of California egg layer premises and analysis of risk factors for Salmonella enterica serotype enteritidis as characterized by manure drag swabs; Castellan DM et al.; This cross-sectional, double-blind study reports the prevalence of Salmonella enterica serotype enteritidis (SE) on California egg layer premises using single vs . pooled manure drag swabs and presents a description of egg production and management systems in the state and an initial analysis of risk factors for SE . The study included 91% of all known eligible egg premises in California, representing the majority of eggs produced in the state . The overall prevalence of SE on California egg layer premises was 10.5%, while 1.1% of all rows sampled were positive for SE . The percentage of positive rows for SE on any premises never exceeded 25% of the 16 swabs collected per premises . A description of egg production and management on California egg layer premises is presented . Statistically significant associations for SE were not evident and were limited because of sample size and the low prevalence of SE on California egg layer premises . Several biological and management factors, such as flock health, stage of production, manure management, ventilation, and watering systems, show trend associations with premises positive for SE and require further investigation . Manure drag swabs serve as a useful tool to validate the core components of an egg quality assurance program for SE based on process control principles.

Avian Dis, 2004 Sep, 48(3), 445 - 52
Comparison of different attenuation strategies in development of a Salmonella hadar vaccine; Roland K et al.; The purpose of this work was to develop a live, attenuated vaccine strain to protect chickens against colonization by group C Salmonella . We constructed two candidate vaccines: a deltacya deltacrp derivative and a deltaphoP derivative of Salmonella hadar . White Leghorn chickens were vaccinated at day of age and at 2 wk with one of the two strains . A nonvaccinated group served as a control . At 4 wk of age, all birds were challenged with wild-type S . hadar and necropsied 6 days later . Numbers of S . hadar in the ceca were determined . Enzyme-linked immunosorbent assay-derived serum immunoglobulin G responses against S . hadar lipopolysaccharide indicated that both strains induced a serum antibody response . The average optical density450 for birds vaccinated with the deltaphoP or deltacya deltacrp derivatives was 0.456 and 0.881, respectively . Although the deltacya deltacrp derivative induced higher levels of serum antibody, it did not provide an immune response protective against colonization by S . hadar . Conversely, birds vaccinated with the deltaphoP strain showed significant protection against S . hadar challenge . Seventy percent of the nonvaccinates, 60% of the deltacya deltacrp vaccinates, and 15% of deltaphoP vaccinates were positive for S . hadar in tissues . In a second experiment, birds were vaccinated with either the deltaphoP strain or buffer and challenged with a 10-fold higher dose than in the first experiment . After challenge, all of the birds in both groups were colonized . The geometric mean number of cecal S . hadar isolated from the control group was 1.0 x 10(6) colony-forming units (CFU)/g, and from the vaccinated group, this value was 32 CFU/g, indicating a four to five log reduction in colonization by the challenge strain.

Environ Mol Mutagen, 2004, 44(5), 372 - 86
History of the science of mutagenesis from a personal perspective; Malling HV; A career in the study of mutagenesis spanning 50 years is a gift few scientists have been bestowed . My tenure in the field started in 1953, the year the structure of DNA became known (Watson and Crick {1953}: Nature 171:737) . Before that time, it was suspected that DNA was the genetic material based on the research of Oswald T . Avery (Avery et al . {1944}: J Exp Med 79:137), but many scientists still believed that proteins or polysaccharides could be the genetic material . The present article describes a lifetime of personal experience in the field of chemical mutagenesis . The methods used to treat viruses with chemical mutagens were well developed in the 1950s . Here I review the early use of nitrous acid and hydroxylamine as mutagens in eukaryotes, the development of methods for the metabolic activation of mutagens by microsomal preparations, and the selection of a mutant tester set for the qualitative characterization of the mutagenic activity of chemicals . These studies provided critical background information that was used by Bruce Ames in the development of his Salmonella/microsome assay, widely known as the Ames test (Ames et al . {1973}: Proc Nat Acad Sci USA 70:2281-2285) . This article also describes how a set of diagnostic chemical mutagens was selected and used to identify the molecular nature of gene mutations . Today, DNA sequencing has replaced the use of diagnostic mutagens, but studies of this kind formed the foundation of modern mutation research . They also helped set the stage for the organization of the Environmental Mutagen Society and the Environmental Mutagen Information Center, which are described . The article ends with the development of mammalian single-cell mutation assays, the first system for studying in vivo mutagenesis using recoverable vectors in transgenic animals, other mutation assays in intact mammals, and my thoughts on the critically important area of germ cell mutagenesis . This narrative is not a complete autobiographical account, in that I have selected only those experiences that I feel are important for the history of the field and the edification of today's students . I hope I have shown that science not only is a valuable pursuit but can also be fun, stimulating, and satisfying . A good sense of humor and the knowledge that many discoveries come by serendipity are essential . Environ . Mol . Mutagen., 2004 . Published 2004 Wiley-Liss, Inc.

Microbiology, 2004 Nov, 150(Pt 11), 3877 - 87
2-Methylcitrate-dependent activation of the propionate catabolic operon (prpBCDE) of Salmonella enterica by the PrpR protein; Palacios S et al.; The function of the PrpR protein of Salmonella enterica serovar Typhimurium LT2 was studied in vitro and in vivo . The PrpR protein is a sensor of 2-methylcitrate (2-MC), an intermediate of the 2-methylcitric acid cycle used by this bacterium to convert propionate to pyruvate . PrpR was unresponsive to citrate (a close structural analogue of 2-MC) and to propionate, suggesting that 2-MC, not propionate, is the metabolite that signals the presence of propionate in the environment to S . enterica . prpR alleles encoding mutant proteins with various levels of 2-MC-independent activity were isolated . All lesions causing constitutive PrpR activity were mapped to the N-terminal domain of the protein . Removal of the entire sensing domain resulted in a protein (PrpR(c)) with the highest 2-MC-independent activity . Residue A162 is critical to 2-MC sensing, since the mutant PrpR protein PrpR(A162T) was as active as the PrpR(c) protein in the absence of 2-MC . DNA footprinting studies identified the site in the region between prpR and the prpBCDE operon to which the PrpR protein binds . Analysis of the binding-site sequence revealed two sites with dyad symmetry . Results from DNase I footprinting assays suggested that the PrpR protein may have higher affinity for the site proximal to the P(prpBCDE) promoter.

J Immunol, 2004 Nov 15, 173(10), 6338 - 45
Multiple roles of CLAN (caspase-associated recruitment domain, leucine-rich repeat, and NAIP CIIA HET-E, and TP1-containing protein) in the mammalian innate immune response; Damiano JS et al.; NAIP CIIA HET-E and TP1 (NACHT) family proteins are involved in sensing intracellular pathogens or pathogen-derived molecules, triggering host defense responses resulting in caspase-mediated processing of proinflammatory cytokines and NF-kappaB activation . Caspase-associated recruitment domain, leucine-rich repeat, and NACHT-containing protein (CLAN), also known as ICE protease-activating factor, belongs to a branch of the NACHT family that contains proteins carrying caspase-associated recruitment domains (CARDs) and leucine-rich repeats (LRRs) . By using gene transfer and RNA-interference approaches, we demonstrate in this study that CLAN modulates endogenous caspase-1 activation and subsequent IL-1beta secretion from human macrophages after exposure to LPS, peptidoglycan, and pathogenic bacteria . CLAN was also found to mediate a direct antibacterial effect within macrophages after Salmonella infection and to sensitize host cells to Salmonella-induced cell death through a caspase-1-independent mechanism . These results indicate that CLAN contributes to several biological processes central to host defense, suggesting a prominent role for this NACHT family member in innate immunity.

J Vet Med B Infect Dis Vet Public Health, 2004 Oct-Nov, 51(8-9), 364 - 9
Spread of resistant bacteria and resistance genes from animals to humans--the public health consequences; Molbak K; The paper reviews the lines of evidence which link the use of antimicrobial drugs for food animals with the emergence of antimicrobial drug resistance in bacteria pathogenic to humans, with a particular focus on the public health aspects . Deductions from the epidemiology of food-borne infections, ecological studies, outbreak investigations, typing studies and direct epidemiological observations show that resistant bacteria are transferred from food animals to man . In addition to transfer in the food chain, exchange of mobile genetic elements among commensal and pathogenic bacteria contributes to the emergence of drug resistance . There is growing evidence that this has measurable consequences for human public health . One consequence is increased transmission supported by unrelated use of anti-microbials in humans . Other consequences are related to reduced efficacy of early empirical treatment, limitations in the choices for treatment after confirmed microbiological diagnosis, and finally a possible coselection of virulence traits . Recent epidemiological studies have measured these consequences in terms of excess mortality associated with resistance, increased duration of illness, and increased risk of invasive illness or hospitalization following infections with resistant Salmonella.

J Vet Med B Infect Dis Vet Public Health, 2004 Sep, 51(7), 337 - 42
Prevalence and antimicrobial resistance of Salmonella spp . in non-diarrhoeic dogs in Trinidad; Seepersadsingh N et al.; The estimated prevalence and antimicrobial resistances of Salmonella spp . in non-diarrhoeic dogs across Trinidad was determined . The serotypes of Salmonella spp . isolated were also identified . Of a total of 1391 dogs sampled, 50 (3.6%) were positive for Salmonella spp . with 28 different serotypes, the predominant serotypes were Javiana (12), Newport (6), Arechavaleta (5) and Heidelberg (5) . Fifty-seven (85.1%) of 67 isolates exhibited resistance to one or more antimicrobial agents . Of eight antimicrobial agents tested, resistance was exhibited to streptomycin (80.6%), cephalothin (37.3%), neomycin (38.8%) and gentamicin (9.0%) . All isolates were sensitive to ampicillin, norfloxacin, choramphenicol and sulphamethoxazole/trimethoprim . It was concluded that the isolation of the Salmonella spp . from non-diarrhoeic dogs could pose health hazard to their owners as most serotypes are known to be virulent . Furthermore, the prevalence of resistance to antimicrobial agents amongst the Salmonella isolates from these animals indicates susceptibility testing may influence chemotherapeutic choices when treating these isolates.

Niger J Med, 2004 Oct-Dec, 13(4), 383 - 7
Effect of socio-economic status, age and sex on antibody titre profile to Salmonella typhi/paratyphi in Ile-Ife, Nigeria; Zailani SB et al.; BACKGROUND: Typhoid fever remains a great socio-medical problem in many poor and underdeveloped countries, with an estimated 16 million cases and 600,000 deaths occurring each year . Although it has a world wide distribution, typhoid fever is endemic where sanitary controls are inadequate . The distribution of the infection in relation to age and sex has shown that typhoid fever is more prevalent in males than in females with out satisfactory explanation . Also, those in their second and third decades are more susceptible . The aim of the study is to evaluate the effect of socio-economic status, age and sex on antibody titre profile to Salmonella typhi and praratyphi in Ile-Ife, using both healthy individuals with immunological scar to Salmonella typhi/paratyphi and enteric fever patients . METHOD: Healthy volunteers (310) were recruited into the study and clinically diagnosed/culture proven cases (48) were used as control . Widal text was performed on each serum . Slide agglutination was first done, then positive samples were further subjected to tube agglutination for quantitative titration . RESULTS: The relationship between age and antibody titres in both healthy subjects and enteric fever patients is not statistically significant, (P values > 0.05) . From the study also, sex and social status do not influence antibody titres to salmonella typhi/paratyphi (P value > 0.05) . CONCLUSION: The study has shown that age, sex and social class do not statistically influence antibody titre profile to S . typhi/paratyphi in Ile-Ife, south western Nigeria.

Mol Microbiol, 2004 Nov, 54(4), 994 - 1010
Identification of host-specific colonization factors of Salmonella enterica serovar Typhimurium; Morgan E et al.; The severity of infections caused by Salmonella enterica serovar Typhimurium varies depending on the host species . Numerous virulence genes have been identified in S . Typhimurium, largely from studies in mice, but their roles in infections of other species remain unclear . In the most comprehensive survey of its kind, through the use of signature-tagged mutagenesis of S . Typhimurium we have identified mutants that were unable to colonize calf intestines, mutants unable to colonize chick intestines and mutants unable to colonize both species . The type three secretion systems encoded on Salmonella pathogenicity islands (SPIs) 1 and 2 were required for efficient colonization of cattle . However, disruption of these secretion systems only caused a minor defect in S . Typhimurium colonization of chicks . Transposon insertions in SPI-4 compromised S . Typhimurium colonization of cattle, but not chicks . This is the first data confirming a role for SPI-4 in pathogenesis . We have also been able to ascribe a role in colonization for cell surface polysaccharides, cell envelope proteins, and many 'housekeeping' genes and genes of unknown function . We conclude that S . Typhimurium uses different strategies to colonize calves and chicks . This has major implications for vaccine design.

Mol Microbiol, 2004 Nov, 54(4), 887 - 904
The target cell plasma membrane is a critical interface for Salmonella cell entry effector-host interplay; Cain RJ et al.; Salmonella species trigger host membrane ruffling to force their internalization into non-phagocytic intestinal epithelial cells . This requires bacterial effector protein delivery into the target cell via a type III secretion system . Six translocated effectors manipulate cellular actin dynamics, but how their direct and indirect activities are spatially and temporally co-ordinated to promote productive cytoskeletal rearrangements remains essentially unexplored . To gain further insight into this process, we applied mechanical cell fractionation and immunofluorescence microscopy to systematically investigate the subcellular localization of epitope-tagged effectors in transiently transfected and Salmonella-infected cultured cells . Although five effectors contain no apparent membrane-targeting domains, all six localized exclusively in the target cell plasma membrane fraction and correspondingly were visualized at the cell periphery, from where they induced distinct effects on the actin cytoskeleton . Unexpectedly, no translocated effector pool was detectable in the cell cytosol . Using parallel in vitro assays, we demonstrate that the prenylated cellular GTPase Cdc42 is necessary and sufficient for membrane association of the Salmonella GTP exchange factor and GTPase-activating protein mimics SopE and SptP, which have no intrinsic lipid affinity . The data show that the host plasma membrane is a critical interface for effector-target interaction, and establish versatile systems to further dissect effector interplay.

Clin Microbiol Infect, 2004 Nov, 10(11), 1031 - 3
Salmonella Enteritidis in Bosnia and Herzegovina; Uzunovic-Kamberovic S; A comprehensive retrospective analysis of human Salmonella Enteritidis isolates in the Zenica-Doboj Canton of Bosnia and Herzegovina was conducted by inquiry and questionnaire . In the period 1998-2000, 299 isolates of Salmonella spp . were recorded, of which S . Enteritidis accounted for 74.2% . The isolation rate of S . Enteritidis increased during this period, from 12.7 to 25.5 isolates/year/100,000 population . Isolates were obtained all year round, mostly from sporadic cases of infection or limited family outbreaks . Home-made food was identified as the most important source of infection, being implicated in 81% of outbreaks and 81.7% of cases of sporadic infection.

Int Surg, 2004 Jul-Sep, 89(3), 172 - 5
Massive lower gastrointestinal bleeding in typhoid fever; Bozkurt S et al.; Typhoid fever is an infectious disease that is usually treated medically and rarely needs surgical intervention . In this paper, we report three cases of severe colonic involvement in salmonella infection in patients traveling in or coming from endemic areas, resulting in ulceration and massive anorectal bleeding.

Vet Clin North Am Equine Pract, 2004 Dec, 20(3), 587 - 600
Multidrug-resistant Salmonella and nosocomial infections; Dargatz DA et al.; Nosocomial infections are a serious threat to optimum patient care . In addition, nosocomial infections can have far-reaching consequences for the hospital personnel and the financial aspects of the hospital . Nosocomial infections with Salmonella spp have been described among hospitalized equine populations more frequently than any other agent . Salmonella spp associated with hospitalized equids often possess more antimicrobial resistance determinants than do Salmonella spp isolated from healthy horses in the general population . There is little evidence to suggest that resistant salmonellae are more virulent than nonresistant forms . MDR forms of Salmonella complicate the selection of appropriate antimicrobials when they are indicated, however . Furthermore, the use of some antimicrobials may apply selection pressure toward enhanced ability of MDR Salmonella to colonize equine patients . Further research should help to elucidate the risky uses of antimicrobials in the hospital setting and define the role of disinfectants and treatments such as NSAIDs in the ecology of MDR forms of nosocomial infections, including Salmonella . In the meantime, thoughtful selection of when and how to use antimicrobials in equine patients, together with deliberate selection of which antimicrobials to use based on monitoring data and other factors, such as safety and spectrum, is advised.

Vet Clin North Am Equine Pract, 2004 Dec, 20(3), 577 - 85
Salmonella culture: sampling procedures and laboratory techniques; Hyatt DR et al.; In some respects, the multitude of options for isolation of Salmonella and the lack of interlaboratory consistency make Salmonella isolation one of the most variable procedures in veterinary laboratories . Even with the vast number of techniques available, it seems that at least one or two new media become available every year that promise to be more sensitive, more specific,and more rapid . With all the potential media and techniques available, the diagnostic laboratory must choose those that efficiently and accurately give the timely results required clinically and epidemiologically . Many veterinary diagnostic laboratories have invested the time and effort to explore these options and usually have developed standard methods to ensure that their laboratory tests have high sensitivity and specificity . Clients have greater assurance in the accuracy of laboratory results if these standards and the process of deriving them are made available to them . Many laboratories participate in external quality assurance programs to demonstrate their ability to culture microorganisms accurately . These quality control programs are designed to ensure that the client receives the correct answers to questions that are vital for the treatment and health care of their horses . This important information is available only if the initial steps of collecting and shipping the samples have been executed appropriately.

Vet Clin North Am Equine Pract, 2004 Dec, 20(3), 521 - 30, v
Evolution of equine infection control programs; Smith BP; The science of control of infectious diseases in hospitals was born in 1847 when Semmelweis, a physician, ordered his medical students to scrub their hands in chlorinated lime water between patients and demonstrated that this simple procedure resulted ina dramatic decline in patient morbidity and mortality . In the late nineteenth century came huge breakthroughs in the understanding that microorganisms cause many disorders, and methods to eliminate and control these microorganisms were attempted . By 1910, sterile instruments, gowns, masks, and gloves had become standard for surgical procedures in large university human hospitals, and isolation of human and veterinary patients with contagious diseases became standard . With the advent of vaccines, many epidemic viral diseases could be controlled, and antimicrobial drugs allowed many previously devastating bacterial diseases to be treated effectively . Before long, however, bacterial resistance became an important issue and remains so today, particularly for Salmonella and Staphylococcus aureus in horses . Vaccination has decreased the number of animals susceptible to equine influenza and equine herpesvirus 1, yet these contagious diseases still pose a serious issue in large equine veterinary hospitals . The development of equine isolation facilities and improved methods of barn cleaning; mandatory application of procedures, such as handwashing or use of disinfectant hand wipes, to prevent the spread of infectious diseases; and monitoring of antimicrobial resistance and use of restricted antimicrobial drugs were driven by recognition and necessity and have given rise to current equine infection control programs.

Int J Antimicrob Agents, 2004 Nov, 24(5), 428 - 32
The importance of active efflux systems in the quinolone resistance of clinical isolates of Salmonella spp; Escribano I et al.; The aim of this study was to determine the importance of the active elimination of antibiotics by active efflux systems, in the decrease in fluoroquinolone sensitivity of clinical isolates of Salmonella spp . as well as the intrinsic antibiotic activity of certain active efflux system inhibitors . The effect of the active efflux system on the decrease in sensitivity to nalidixic acid, ciprofloxacin, ofloxacin and sparfloxacin was studied by investigating the variation in the in vitro activity of these compounds when assayed in association with reserpine and MC 207.110 . The active efflux systems inhibited by reserpine displayed low activity in the elimination of these compounds, whereas those inhibited by MC 207.110 showed high activity in the elimination of nalidixic acid and sparfloxacin, but were less effective in the elimination of ofloxacin and ciprofloxacin . These two compounds did not exhibit intrinsic inhibitory activity against Salmonella spp . at the concentrations assayed . These mechanisms of resistance to antibiotics are complex and vary depending on the chemical composition of the antibiotics used, and perhaps the inhibitors of these systems, although they do not exhibit any intrinsic antibiotic activity, may be used as adjuvants to increase the activity of certain antibiotics . These mechanisms complement the mutations in the gyrA gene and this supports the thesis that it is necessary to lower the breakpoint established by the NCCLS for ciprofloxacin, since the strains studied have resistance mechanisms that reduce the activity of this drug and may favour the emergence of resistant mutants during treatment.

Plasmid, 2004 Nov, 52(3), 218 - 24
Sequence analysis and characterization of sulfonamide resistance plasmid pRF-1 from Salmonella enterica serovar Choleraesuis; Haneda T et al.; The nucleotide sequence of a small plasmid, designated pRF-1, isolated from Salmonella enterica serovar Choleraesuis, was determined . We identified seven open reading frames (ORFs) encoded by 6066 nucleotides with a total G + C content of 53.6% . Analysis of the complete nucleotide sequence revealed a replicon of pRF-1 to have high similarity to the p15A origin of replication, with a possible cer-like region . ORF1, which is composed of 816 nucleotides, shows a high degree of similarity to dihydropteroate synthetase encoded by the sulII gene from plasmids in several enteropathogenic bacteria, which functions as the sulfonamide resistance determinant . In fact, Salmonella and Escherichia coli strains carrying pRF-1 were found to show strong resistance to sulfathiazole, suggesting that orf1 is a functional gene . Four of seven ORFs were found to encode putative proteins of unknown function.

Chem Pharm Bull (Tokyo), 2004 Nov, 52(11), 1342 - 4
Antimicrobial screening and quantitative determination of benzoic acid derivative of Gomphrena celosioides by TLC-densitometry; de Moura RM et al.; The antimicrobial activity of ethanolic extract and pure compounds of Gomphrena celosioides have been screened by Kirby-Bauer method . Quantitative determination of 4-hydroxy-3-methoxy-benzoic acid in stems, leaves, flowers and roots was established by TLC-densitometry . Results showed significant activity against Staphylococcus aureus and Salmonella typhi . There were no significant differences in the determined benzoic acid derivative.

J Bacteriol, 2004 Nov, 186(22), 7635 - 44
Evidence that a B12-adenosyl transferase is encoded within the ethanolamine operon of Salmonella enterica; Sheppard DE et al.; Adenosylcobalamin (Ado-B12) is both the cofactor and inducer of ethanolamine ammonia lyase (EA-lyase), a catabolic enzyme for ethanolamine . De novo synthesis of Ado-B12 by Salmonella enterica occurs only under anaerobic conditions . Therefore, aerobic growth on ethanolamine requires import of Ado-B12 or a precursor (CN-B12 or OH-B12) that can be adenosylated internally . Several known enzymes adenosylate corrinoids . The CobA enzyme transfers adenosine from ATP to a biosynthetic intermediate in de novo B12 synthesis and to imported CN-B12, OH-B12, or Cbi (a B12 precursor) . The PduO adenosyl transferase is encoded in an operon (pdu) for cobalamin-dependent propanediol degradation and is induced by propanediol . Evidence is presented here that a third transferase (EutT) is encoded within the operon for ethanolamine utilization (eut) . Surprisingly, these three transferases share no apparent sequence similarity . CobA produces sufficient Ado-B12 to initiate eut operon induction and to serve as a cofactor for EA-lyase when B12 levels are high . Once the eut operon is induced, the EutT transferase supplies more Ado-B12 during the period of high demand . Another protein encoded in the operon (EutA) protects EA-lyase from inhibition by CN-B12 but does so without adenosylation of this corrinoid.

J Bacteriol, 2004 Nov, 186(22), 7626 - 34
Lack of YggX results in chronic oxidative stress and uncovers subtle defects in Fe-S cluster metabolism in Salmonella enterica; Skovran E et al.; As components involved in Fe-S cluster metabolism are described, the challenge becomes defining the integrated process that occurs in vivo based on the individual functions characterized in vitro . Strains lacking yggX have been used here to mimic chronic oxidative stress and uncover subtle defects in Fe-S cluster metabolism . We describe the in vivo similarities and differences between isc mutants, which have a known function in cluster assembly, and mutants disrupted in four additional loci, gshA, apbC, apbE, and rseC . The latter mutants share similarities with isc mutants: (i) a sensitivity to oxidative stress, (ii) a thiamine auxotrophy in the absence of the YggX protein, and (iii) decreased activities of Fe-S proteins, including aconitase, succinate dehydrogenase, and MiaB . However, they differ from isc mutants by displaying a phenotypic dependence on metals and a distinct defect in the SoxRS response to superoxides . Results presented herein support the proposed role of YggX in iron trafficking and protection against oxidative stress, describe additional phenotypes of isc mutants, and suggest a working model in which the ApbC, ApbE, and RseC proteins and glutathione participate in Fe-S cluster repair.

J Bacteriol, 2004 Nov, 186(22), 7586 - 92
Analysis of the cytoplasmic domains of Salmonella FlhA and interactions with components of the flagellar export machinery; McMurry JL et al.; Most flagellar proteins are exported via a type III export apparatus which, in part, consists of the membrane proteins FlhA, FlhB, FliO, FliP, FliQ, and FliR and is housed within the membrane-supramembrane ring formed by FliF subunits . Salmonella FlhA is a 692-residue integral membrane protein with eight predicted transmembrane spans . Its function is not understood, but it is necessary for flagellar export . We have created mutants in which potentially important sequences were deleted . FlhA lacking the amino-terminal sequence prior to the first transmembrane span failed to complement and was dominant negative, suggesting that the sequence is required for function . Similar effects were seen in a variant lacking a highly conserved domain (FHIPEP) within a putative cytoplasmic loop . Scanning deletion analysis of the cytoplasmic domain (FlhAc) demonstrated that substantially all of FlhAc is required for efficient function . Affinity blotting showed that FlhA interacts with several other export apparatus membrane proteins . The implications of these findings are discussed, and a model of FlhA within the export apparatus is presented.

J Bacteriol, 2004 Nov, 186(22), 7508 - 20
Evolutionary dynamics of insertion sequences in Helicobacter pylori; Kalia A et al.; Prokaryotic insertion sequence (IS) elements behave like parasites in terms of their ability to invade and proliferate in microbial gene pools and like symbionts when they coevolve with their bacterial hosts . Here we investigated the evolutionary history of IS605 and IS607 of Helicobacter pylori, a genetically diverse gastric pathogen . These elements contain unrelated transposase genes (orfA) and also a homolog of the Salmonella virulence gene gipA (orfB) . A total of 488 East Asian, Indian, Peruvian, and Spanish isolates were screened, and 18 and 14% of them harbored IS605 and IS607, respectively . IS605 nucleotide sequence analysis (n = 42) revealed geographic subdivisions similar to those of H . pylori; the geographic subdivision was blurred, however, due in part to homologous recombination, as indicated by split decomposition and homoplasy tests (homoplasy ratio, 0.56) . In contrast, the IS607 populations (n = 44) showed strong geographic subdivisions with less homologous recombination (homoplasy ratio, 0.2) . Diversifying selection (ratio of nonsynonymous change to synonymous change, >>1) was evident in approximately 15% of the IS605 orfA codons analyzed but not in the IS607 orfA codons . Diversifying selection was also evident in approximately 2% of the IS605 orfB and approximately 10% of the IS607 orfB codons analyzed . We suggest that the evolution of these elements reflects selection for optimal transposition activity in the case of IS605 orfA and for interactions between the OrfB proteins and other cellular constituents that potentially contribute to bacterial fitness . Taken together, similarities in IS elements and H . pylori population genetic structures and evidence of adaptive evolution in IS elements suggest that there is coevolution between these elements and their bacterial hosts.

J Bacteriol, 2004 Nov, 186(22), 7481 - 9
The Salmonella membrane protein IgaA modulates the activity of the RcsC-YojN-RcsB and PhoP-PhoQ regulons; Tierrez A et al.; The Salmonella enterica serovar Typhimurium membrane protein IgaA and the PhoP-PhoQ two-component system are used by this pathogen to attenuate the intracellular growth rate within fibroblasts . IgaA has also recently been shown to contribute to virulence by exerting tight repression of the RcsC-YojN-RcsB phosphorelay in host tissues . Here we show that loss of repression of the RcsC-YojN-RcsB system, linked to an R188H mutation in the IgaA protein (igaA1 allele), is accompanied by altered expression of PhoP-PhoQ-activated (pag) genes . The changes in gene expression were different depending on the specific pag gene analyzed . Thus, transcription of ugd, which is required for lipopolysaccharide modification and colanic acid capsule synthesis, was enhanced in the igaA1 mutant . RcsB and its coregulator RcsA promoted this alteration in a PhoP-PmrA-independent manner . Unlike ugd, activation of the RcsC-YojN-RcsB phosphorelay negatively affected the expression of all other pag genes tested . In this case, RcsB alone was responsible for this effect . We also found that PhoP, but not PmrA, negatively modulates the expression of gmm, a gene required for colanic acid synthesis that is regulated positively by RcsC-YojN-RcsB . Finally, it was observed that the fine regulation of pag genes exerted by RcsB requires the RpoS protein and that an active RcsB, but not RcsA, diminishes expression of the phoP gene . These data support the hypothesis that in Salmonella there is an intimate regulatory circuit between the PhoP-PhoQ and RcsC-YojN-RcsB phosphorelays, which is revealed only when the RcsC-YojN-RcsB signaling route is derepressed . Consistent with the phenotypes observed in fibroblast cells, IgaA is predicted to favor expression of the entire PhoP-PhoQ regulon based on its repression of the RcsC-YojN-RcsB phosphorelay.

Scand J Infect Dis, 2004, 36(10), 773 - 4
Fatal transplacental infection with non-typhoidal Salmonella; Schloesser RL et al.; We report a case of transplacentally acquired neonatal sepsis with non-typhoid Salmonella . The infant's mother, a 36-y-old woman, presented with fever and malaise in the 25th week of gestation . Because of a pathological cardiotocogram, Caesarean section was performed a few h following admission . The premature infant had clinical signs of sepsis with multiorgan failure and died 4 d later despite intensive medical care . Maternal blood cultures and swab cultures taken from within the uterine cavity and from cutaneous and mucosal surfaces of the infant grew Salmonella virchow . This case and the few sporadic reports in the literature indicate that septicaemia due to non-typhoidal Salmonella spp . during pregnancy is highly lethal to the foetus or newborn, whereas prognosis for the mother apparently is excellent.

J Environ Pathol Toxicol Oncol, 2004, 23(4), 267 - 78
Comparison of genotoxicity of textile dyestuffs in Salmonella mutagenicity assay, in vitro micronucleus assay, and single cell gel/comet assay; Wollin KM et al.; The mutagenicity of textile dyes is an important consideration for the assurance of consumer protection and work safety . The mutagenicity testing of textile dyestuffs is crucial for accurately predicting health risks for consumers and workers exposed to dyes . Unfortunately, these data are often lacking . We studied the genotoxic activity of ten selected commercial textile dyestuffs, which are made up of mixtures of azo dyes and azo metal complex dyes as well as two anthraquinone dyestuffs . We used the Salmonella mutagenicity assay and cultured human keratinocytes (HaCaT cell line) . In the S . typhimurium strain TA98, with and without S9, eight often dyestuffs investigated, and in strain TA 100, with and without S9, six often dyes caused frameshift mutations and base-pair substitutions in the dose range of 1-5000 microg/plate in a dose-related manner . All dyes, including those negative in the Salmonella mutagenicity assay, induced clastogenic effects in the in vitro micronucleus (MN) test in HaCaT cells as direct-acting mutagens in the concentration range of 5-150 microg/mL and with maximum MN frequencies between 1.1 and 7.2%, compared to negative controls that showed 0.2-0.4% MN cells . In the single cell gel/comet assay, all ten dyestuffs investigated caused DNA damage in HaCaT keratinocytes . The alkaline (pH >13) version used is capable of detecting DNA single strand breaks, alkali-labile sites, and DNA-DNA/DNA-protein cross-linking . Under the conditions of these screening tests, the textile dyes investigated are direct-acting genotoxic substances . The HaCaT cells testing protocol proposed has been shown to be an appropriate test system for evaluating mutagenicity of textile dyes on a base level.

Trop Doct, 2004 Oct, 34(4), 198 - 200
Non-typhoidal salmonella bacteraemia--an under-recognized feature of AIDS in African adults; Kankwatira AM et al.; Non-typhoidal salmonella (NTS) infections are severe, invasive and recurrent in the HIV-infected adult, and NTS are the commonest cause of hospital admission with bacteraemia in sub-Saharan Africa . NTS bacteraemia typically presents in patients with HIV/AIDS once the CD4 count falls below 200 cells/microL . In-patient mortality is 35%-60%, and is highest in patients with confusion or severe anaemia . Among survivors, 25%-45% may have single or multiple recurrences of NTS bacteraemia 1-6 months after the first illness, requiring retreatment . Diagnosis relies on blood culture, so in many areas this disease cannot be definitively diagnosed, and must be empirically treated . Treatment is guided by local antibiotic sensitivities; fluoroquinolones are particularly useful for initial treatment if there is multidrug reistance to other agents, and may result in lower recurrence rates than other agents . Where possible, long-term secondary chemoprophylaxis to prevent recurrence is advisable . Successful ARV treatment also prevents recurrence . There is inadequate knowledge about the epidemiology of carriage and transmission among at-risk populations.

Trop Doct, 2004 Oct, 34(4), 195 - 8
Bacterial infections in children with HIV/AIDS; Molyneux E; HIV/AIDS affects over 850,000 children in Africa . Bacterial infections are frequent in this group of children . Pneumonia, meningitis and septicaemia are especially common, recurrent and most often caused by Streptococcus pneumoniae . Salmonella spp are the most frequently isolated causative agent of septicaemia in malarial areas . Soft tissue, eye and oral infections have a higher incidence in HIV-infected than uninfected children . In all instances the causative agents are not dissimilar from those that cause disease in HIV-uninfected children, but the mortality is greater . Increased bacterial resistance to first line antibiotics has been reported and the use of cotrimoxazole prophylaxis may further influence the resistance pattern of common bacteria.

Wien Klin Wochenschr, 2003, 115 Suppl 3, 68 - 71
Hygienic evaluation of terraria inhabited by amphibians and reptiles: cryptosporidia, free-living amebas, salmonella; Hassl A et al.; Amphibians and reptiles are popular pet animals in about 90.000 Austrian households despite their frequently debated capacity to transmit diseases associated with animal keeping . We studied the epidemiological significance of the triangle animal keeper, exotic pet animal, and feed mice by investigating the frequency of three intestinal infestations, caused by cryptosporidia, opportunistic free-living amebas and salmonella, in amphibians and reptiles living in a public vivarium . In addition to recording the first known occurrence of Naegleria australiensis in Austria, and of this species and of Acanthamoeba polyphaga in the feces of reptiles worldwide, we also detected a strong association between Salmonella subspecies I and captive reptiles and between S . sub-species III and free-living lizards . Thus, animal keeper, the exotic animals kept, and the feed mice may constitute an epidemiological pool for the interchange of these infectious agents . This new epidemiological situation may cause an increase of some opportunistic and exotic diseases such as reptile-borne salmonellosis . Despite the perceived benefits of keeping exotic animals in a household, the general public and especially those who have an immunodeficiency must be made aware of the danger of infectious diseases possibly being spread by their pets.

J Food Prot, 2004 Oct, 67(10), 2342 - 53
Fresh produce: a growing cause of outbreaks of foodborne illness in the United States, 1973 through 1997; Sivapalasingam S et al.; Fresh produce is an important part of a healthy diet . During the last three decades, the number of outbreaks caused by foodborne pathogens associated with fresh produce consumption reported to the Centers for Disease Control and Prevention has increased . To identify trends, we analyzed data for 1973 through 1997 from the Foodborne Outbreak Surveillance System . We defined a produce-associated outbreak as the occurrence of two or more cases of the same illness in which epidemiologic investigation implicated the same uncooked fruit, vegetable, salad, or juice . A total of 190 produce-associated outbreaks were reported, associated with 16,058 illnesses, 598 hospitalizations, and eight deaths . Produce-associated outbreaks accounted for an increasing proportion of all reported foodborne outbreaks with a known food item, rising from 0.7% in the 1970s to 6% in the 1990s . Among produce-associated outbreaks, the food items most frequently implicated included salad, lettuce, juice, melon, sprouts, and berries . Among 103 (54%) produce-associated outbreaks with a known pathogen, 62 (60%) were caused by bacterial pathogens, of which 30 (48%) were caused by Salmonella . During the study period, Cyclospora and Escherichia coli O157:H7 were newly recognized as causes of foodborne illness . Foodborne outbreaks associated with fresh produce in the United States have increased in absolute numbers and as a proportion of all reported foodborne outbreaks . Fruit and vegetables are major components of a healthy diet, but eating fresh uncooked produce is not risk free . Further efforts are needed to better understand the complex interactions between microbes and produce and the mechanisms by which contamination occurs from farm to table.

J Food Prot, 2004 Oct, 67(10), 2337 - 41
Effects of preparation methods on the microbiological safety of home-dried meat jerky; Nummer BA et al.; Historically, drying meats to produce jerky was conisidered to be a safe preservation process and the convenience and flavor of jerky has made it a popular food product for home food preservers . Recent outbreaks of foodborne illness related to both home-dried and commercially manufactured jerky have raised concerns about the safety of the product . Some traditional home recipes and drying processes were shown to be inadequate to destroy Escherichia coli O157, Salmonella, Staphylococcus aureus, and Listeria monocytogenes in both whole-muscle and ground-meat jerky . Several research studies have identified processes such as precooking meats before drying, usingacidic marinades, cooking meats after drying, or some combination of these treatments that can destroy pathogens of concern to produce microbiologically safe and palatable meat jerky at home.

J Food Prot, 2004 Oct, 67(10), 2277 - 9
Survival of Salmonella Montevideo on tomato leaves and mature green tomatoes; Rathinasabapathi B; Survival of Salmonella Montevideo on tomato leaf and mature green tomatoes was examined . When spiked on the surfaces of excised leaves from greenhouse tomato plants, Salmonella Montevideo survived poorly if the leaves were allowed to dry . After spot inoculation of 6.6 log CFU per leaflet and incubation for 48 h at 60% relative humidity, the leaflets were dried, and surviving Salmonella were reduced 2.8 to 3.7 log CFU per leaflet . However, when leaves spiked with Salmonella were supported on hydroponic nutrient medium and incubated at 100% relative humidity, there was no significant reduction of surviving bacteria for at least 6 days . Exposure of mature green tomatoes to ethylene (100 ppm at 100% relative humidity and 20 degrees C for 6 days) did not significantly affect the survival of Salmonella on their surfaces . The significance of these data to pre- and postharvest safety of tomato is discussed.

J Food Prot, 2004 Oct, 67(10), 2269 - 73
Influence of a nonfavorable environment, egg white, on resistance to heat and disinfectant, adhesion, and virulence of Salmonella enteritidis; Baron F et al.; Although liquid egg white may be subjected to limited heat treatment when it is used in the fabrication of various foodstuffs, pathogenic bacteria such Salmonella Enteritidis could persist in this environment . Liquid egg white is not a favorable medium for Salmonella growth because of its alkaline pH and iron deficiency and the presence of ovotransferrin . Microorganisms adapted to a nonfavorable environment are often more resistant to stresses than are their laboratory-cultured counterparts . The objective of this study was to determine whether Salmonella exposed to an environment mimicking egg white conditions exhibited modified behavior that could have an impact on food safety . A medium resembling egg white (filtrate of egg white with added ovotransferrin) was used as an adaptation treatment to mimic the stress imparted by the egg white environment . There were no changes in resistance to heat and disinfection, in stainless steel adhesion, or in the virulence of Salmonella Enteritidis cultivated in the egg white medium . Egg white conditions do not appear to make Salmonella more virulent or more difficult to inactivate.

J Food Prot, 2004 Oct, 67(10), 2263 - 8
Irradiation to kill Escherichia coli O157:H7 and Salmonella on ready-to-eat radish and mung bean sprouts; Bari ML et al.; A study was carried out to evaluate the effectiveness of ionizing radiation in eliminating Escherichia coli O157:H7 and Salmonella on commercial ready-to-eat radish and mung bean sprouts and to assess the chemical and physical quality of these sprouts . The use of ionizing radiation was investigated as a means of reducing or totally inactivating these pathogens, if present, on the sprouts . Treatment of mung bean and radish sprouts with a dose of 1.5 and 2.0 kGy, respectively, significantly reduced E . coli O157:H7 and Salmonella to nondetectable limits . The total vitamin C content was gradually reduced with the increase in irradiation dose (P < 0.0001) . However, the effect of storage interval on the loss of vitamin C was nonsignificant for radish sprouts and significant for mung bean sprouts (P < 0.04) . The color, firmness, and overall visual quality of the tested sprouts were acceptable when effective doses were applied to both radish and mung bean sprouts . Therefore, ionizing radiation could be useful in reducing the population of pathogens on sprouts and yet retain acceptable quality parameters.

J Food Prot, 2004 Oct, 67(10), 2165 - 70
A multistate outbreak of Salmonella enterica serotype typhimurium infection linked to raw milk consumption--Ohio, 2003; Mazurek J et al.; In December 2002, the Ohio Department of Health was notified of two children with Salmonella infection . Both had a history of drinking raw milk from a combination dairy-restaurant-petting zoo (dairy) . The dairy was the only establishment in Ohio licensed to sell raw milk and reported 1.35 million visitors annually . We investigated to determine the extent of the outbreak and identify illness risk factors . A case patient was any person with pulsed-field gel electrophoresis-matched Salmonella enterica serotype Typhimurium from 30 November 2002 to 18 February 2003 . Sixty-two met the confirmed case definition . Forty dairy case patient patrons were included in a case-control study; 56 controls were their well meal companions . Consumption of raw milk was found to be associated with illness (odds ratio, 45.1; 95% confidence interval, 8.8 to 311.9) . The dairy discontinued selling raw milk . Because 27 other states still allow the sale of raw milk, awareness of the hazards of its consumption should be raised and relevant regulations carefully reviewed.

J Food Prot, 2004 Oct, 67(10), 2151 - 7
Effectiveness of cleaners and sanitizers in killing Salmonella Newport in the gut of a free-living nematode, Caenorhabditis elegans; Kenney SJ et al.; Caenorhabditis elegans, a free-living nematode found in soil, has been shown to ingest human enteric pathogens, thereby potentially serving as a vector for preharvest contamination of fruits and vegetables . A study was undertaken to evaluate the efficacy of cleaners and sanitizers in killing Salmonella enterica serotype Newport in the gut of C . elegans . Adult worms were fed nalidixic acid-adapted cells of Escherichia coli OP50 (control) or Salmonella Newport for 24 h, washed, placed on paper discs, and incubated at temperatures of 4 or 20 degrees C and relative humidities of 33 or 98% for 24 h . Two commercial cleaners (Enforce and K Foam Lo) and four sanitizers (2% acetic acid, 2% lactic acid, Sanova, and chlorine {50 and 200 microg/ml}) were applied to worms for 0, 2, or 10 min . Populations of E . coli and Salmonella Newport (CFU per worm) in untreated and treated worms were determined by sonicating worms in 0.1% peptone and surface plating suspensions of released cells on tryptic soy agar containing nalidixic acid . Populations of Salmonella Newport in worms exposed to 33 or 98% relative humidity at 4 degrees or 33% relative humidity at 20 degrees C were significantly (P < or = 0.05) lower than the number surviving exposure to 98% relative humidity at 20 degrees C . In general, treatment of desiccated worms with cleaners and sanitizers was effective in significantly (P < or = 0.05) reducing the number of ingested Salmonella Newport . Results indicate that temperature and relative humidity influence the survival of Salmonella Newport in the gut of C . elegans, and cleaners and sanitizers may not eliminate the pathogen.

J Food Prot, 2004 Oct, 67(10), 2143 - 50
Effect of nisin in combination with EDTA, sodium lactate, and potassium sorbate for reducing Salmonella on whole and fresh-cut cantaloupet; Ukuku DO et al.; Nisin (50 microg/ml), EDTA (0.02 M, disodium salt), sodium lactate (NaL, 2%), and potassium sorbate (KS, 0.02%) were tested individually and in various combinations as sanitizer treatments for reducing Salmonella on whole and fresh-cut cantaloupe . Whole cantaloupe and fresh-cut pieces were inoculated with a five-strain cocktail of Salmonella to give 4.76 +/- 0.23 log CFU/cm2 and 3.42 +/- 0.13 log CFU/g, respectively . Inoculated whole melons and fresh-cut pieces were stored at 5 degrees C for 7 days . Washing treatments were applied to inoculated whole melons at days 0, 3, and 7 of storage, and surviving bacterial populations were determined . The effect of the washing treatments on transfer of Salmonella to fresh-cut pieces prepared immediately after treatment was also determined . Directly inoculated fresh-cut pieces were treated at day 0, and surviving bacteria were enumerated at days 0, 3, and 7 of storage . The combination treatments of nisin-EDTA, nisin-NaL, nisin-KS, NaL-KS, and nisin-NaL-KS all resulted in reductions of approximately 3 log CFU/cm2 at day 0 for whole melons . When tested alone, all compounds, along with water washes, were ineffective . After 3 and 7 days of storage, the five combination washing treatments were less effective, resulting in reductions of approximately 2 log CFU/cm2 . None of the combination treatments completely eliminated transfer of pathogen survivors to fresh-cut pieces . The combination treatments nisin-NaL, nisin-KS, NaL-KS, and nisin-NaL-KS, but not nisin-EDTA, gave significant (P < 0.05) reductions of Salmonella directly inoculated onto fresh-cut pieces . Washing with nisin-NaL-KS was significantly (P < 0.05) more effective than the other three combination treatments, resulting in a reduction of 1.4 CFU/g . Inhibition by the four effective treatments carried over from day 0 through day 7 of storage, with no increase in the population of Salmonella on the stored fresh-cut pieces . Sensory evaluations indicated that treatment of fresh-cut pieces with nisin-NaL and NaL-KS, but not nisin-KS or nisin-NaL-KS, were acceptable in terms of appearance, odor, and overall acceptability . After the required regulatory approval, treatment of whole cantaloupe with nisin in combination with EDTA, NaL, KS, or NaL and KS and of fresh-cut pieces with nisin-NaL or NaL-KS could help ensure the microbiological safety of fresh-cut cantaloupe.

Commun Dis Intell, 2003, 27(4), 508 - 12
Outbreak of Salmonella Potsdam associated with salad dressing at a restaurant; Unicomb L et al.; Between 27 January and 7 February 2002, 12 cases of Salmonella Potsdam infection were notified to NSW Health of which nine were residents of the Hunter Health Area . Interviews with two cases notified by two local doctors initiated the investigation and revealed exposure to foods from the same restaurant (restaurant A) . All New South Wales S . Potsdam cases, those accompanying cases to restaurant A and people from restaurant A booking lists were interviewed . Of the 34 people interviewed, 17 met the case definition . The epidemiological investigation did not detect a food source of S . Potsdam infection, however, shell egg-based Caesar salad dressing and mayonnaise, and a swab of a cap from a mayonnaise bottle collected at restaurant A tested positive for S . Potsdam . Environmental and laying hen feed samples from the egg supplier to restaurant A and meat meal, (the major component of laying hen feed) tested positive for various Salmonella serotypes . The investigation identified problems of inadequate cleaning, time-temperature abuse, and ignorance of the hazardous nature of raw shell eggs at the restaurant level, poor sanitation and a lack of hygiene inspections at the egg production level, and problems with cleaning, storage and lack of bacterial monitoring of final product at the animal rendering plant . Investigation of 12 notified cases of Salmonella resulted in public health interventions, which likely prevented further cases of foodborne disease due to Salmonella and other pathogens in the Hunter Health Area and elsewhere in New South Wales.

Jpn J Infect Dis, 2004 Oct, 57(5), 216 - 9
Cryptosporidium Spp., a frequent cause of diarrhea among children at the Korle-Bu Teaching Hospital, Accra, Ghana; Adjei AA et al.; This report presents the results of a study conducted at the Child Health Department, Korle-Bu Teaching Hospital, Accra, Ghana, between the months of October 2001 and June 2002 . Stool samples from 227 children with diarrhea and 77 children without diarrhea, aged less than 5 years, were tested for Cryptosporidium spp . Prevalence rates were 27.8 and 15.6% in children with and without diarrhea, respectively . Cryptosporidium infection was found to be high in children between the ages of 6 and 24 months . Cryptosporidium spp . was more common in malnourished children, but was not isolated in children under 6 months of age who were exclusively breastfed . Neither the presence of domestic animals, abdominal pain, blood in stool, nausea, vomiting, nor the consumption of untreated water was associated with Cryptosporidium spp . infection . Shigella, Salmonella, and yeast-like organisms were the most frequently identified enteropathogenic bacteria . In summary, this study demonstrates the prevalence of Cryptosporidium spp . among Ghanaian children.

Jpn J Infect Dis, 2004 Oct, 57(5), 210 - 1
Long-term post-Salmonella reactive arthritis due to Salmonella Blockley; Wilson IG et al.; We describe the case of a patient who became ill with Salmonella Blockley food poisoning while working in Cyprus in August 1994 . As his diarrhoea resolved he began to suffer from lower limb joint pains which were diagnosed as acute salmonella reactive arthritis . His condition deteriorated, then improved somewhat over a period of 2 years, but he continued to suffer symptoms over 5 years after infection . This case predates other reported cases of S . Blockley infection in Cyprus by 4 years . S . Blockley is associated with chickens, and the chicken meal is the probable source of his infection . This case is of interest since it demonstrates the emergence of the serovar outside South East Asia where it is common, and shows that information on the incidence and duration of reactive arthritis caused by serovars other than S . Enteritidis and S . Typhimurium is limited.

Euro Surveill . 2004 Oct 01;9(10) {Epub ahead of print}
Occurrence of Salmonella Enteritidis phage type 29 in Austria : an opportunity to assess the relevance of chicken meat as source of human salmonella infections; Berghold C et al.; Assuming that the various phage types of Salmonella Enteritidis (S . Enteritidis) are largely equally virulent, the importance of certain foods as sources of infection for human salmonellosis can be deduced from differences in the distribution of phage types in human and non-human samples . In 2002, S . Enteritidis phage type 29 (PT29) was first isolated from non-human test samples in Austria . S . Enteritidis PT29 accounted for 44 (27.7%) of 159 S . Enteritidis strains, derived from veterinary samples of chicken (e.g . meat, giblets) or chicken habitations (e.g . swabs from the coop and excrement) . At the food retail level (chicken meat, chicken liver), five (13.1%) of 38 S . Enteritidis isolates were PT29 . The proportion of S . Enteritidis PT29 in human samples was much lower . Only 0.4% (30 human primary isolates) of all S . Enteritidis isolates in the year 2002, and 0.33% (23 human primary isolates) of all human S . Enteritidis strains in 2003 were PT29 . In our opinion, the discrepancy between the high prevalence of S . Enteritidis PT29 in broilers and chicken meat and the low number of PT29 cases in humans indicates that chicken meat of Austrian origin is currently only a minor source of human S . Enteritidis infections.

Mutat Res, 2004 Dec 12, 564(2), 179 - 93
In vitro potential genotoxic effects of surface drinking water treated with chlorine and alternative disinfectants; Guzzella L et al.; A battery of in vitro short-term tests revealing different genetic end-points was set up in order to study surface-water genotoxicity after disinfection with different biocides: sodium hypochlorite (NaClO), chlorine dioxide (ClO(2)) and peracetic acid (PAA) . The surface water both before and after disinfection was concentrated by adsorption on C(18) silica cartridges and the concentrates containing non-volatile organics were divided into different portions for chemical analyses and biological assays . The following in vitro tests were conducted on the water concentrates dissolved in DMSO: the Salmonella mutagenicity assay with S . typhimurium strains TA98 and TA100; the SOS Chromotest with Escherichia coli, the Microtox and Mutatox assays with Vibrio fischeri; and gene conversion, point mutation and mitochondrial DNA mutability assays with D7 diploid Saccharomices cerevisiae strain . The results show that the SOS Chromotest and the yeast assays are highly sensitive in detecting genotoxicity . The surface-water extracts were very often toxic to most of the test organisms considered, partially masking their potential mutagenic activity . Therefore, the assays with E . coli and with S . cerevisiae are more likely to show a mutagenic effect because these organisms are generally less sensitive to most toxic compounds . Among the tested disinfectants, NaClO and ClO(2) increased water genotoxicity, whereas PAA was able to slightly reduce raw water activity . However, because the organic compounds in the lake water varied with the season of the year, the disinfection processes, at times, both increased and decreased the raw water activity.

Environ Sci Technol, 2004 Oct 1, 38(19), 5127 - 33
Toxicity characterization of complex mixtures using biological and chemical analysis in preparation for assessment of mixture similarity; Cizmas L et al.; In the United States, several proposed approaches for using bioassays for the risk assessment of complex hazardous mixtures require that selected mixtures be "sufficiently similar" to each other . The goal of this research was to evaluate the utility of a protocol using in vitro bioassays and chemical analysis as a basis for assessing mixture similarity . Two wood preserving wastes (WPWs) containing polycyclic aromatic hydrocarbons and pentachlorophenol were extracted and fractionated to generate potentially similar mixtures . Chemical analysis was conducted using gas chromatography/mass spectrometry . Genotoxicity was evaluated using the Salmonella/microsome and Escherichia coli prophage induction assays . The crude extract of one WPW was also tested in the chick embryotoxicity screening test (CHEST) assay . The CHEST assay provided the most sensitive measurement of toxicity . Overall, the biological potency of the samples was not well correlated with predicted potency based on chemical analysis . Although several mixtures appeared similar based on chemical analysis, the magnitude of the response in bioassays was often dissimilar . Fractionation was required to detect the genotoxicity of mixture components in vitro . The results confirm the need for an integrated protocol, combining chemical analysis, fractionation, and biological testing to characterize the risk associated with complex mixtures.

Antimicrob Agents Chemother, 2004 Nov, 48(11), 4263 - 70
Infections with nontyphoidal Salmonella species producing TEM-63 or a novel TEM enzyme, TEM-131, in South Africa; Kruger T et al.; Salmonella spp . producing extended-spectrum beta-lactamases (ESBLs) have been reported in many countries, but there is no information on their prevalence in Africa . ESBL-producing Salmonella enterica serotype Isangi and S . enterica serotype Typhimurium strains have been noted in South Africa since 2001 . A total of 160 consecutive isolates of Salmonella spp . were collected from 13 hospitals located in different cities in South Africa over a 5-month period from December 2002 to April 2003 . All strains were screened for production of ESBLs by the double disk diffusion test and for AmpC production by assessing resistance to cefoxitin . bla(SHV), bla(TEM), bla(CTX-M), and bla(CMY-2) were sought from all ESBL-positive and cefoxitin-resistant isolates . A total of 15.6% (25 of 160) isolates produced SHV or TEM ESBLs, and 1.9% (3 of 160) produced CMY-2 . Nine S . enterica serotype Typhimurium, eight S . enterica serotype Isangi, and three S . enterica serotype Muenchen strains produced either TEM-63 or a derivative of TEM-63 designated TEM-131 . Both TEM-63 and TEM-131 have an isoelectric point of 5.6, and their sequences have the following amino acid substitutions compared to the TEM-1 sequence: Leu21Phe, Glu104Lys, Arg164Ser, and Met182Thr . Additionally, TEM-131 has an Ala237Thr substitution . ESBL-producing Salmonella spp . have become a significant public health problem in South Africa with particular implications for the treatment of serious nontyphoidal Salmonella infections in children, for whom extended-spectrum cephalosporins were the preferred treatment.

Antimicrob Agents Chemother, 2004 Nov, 48(11), 4130 - 5
Emergence of multidrug-resistant Salmonella enterica serovar typhi in Korea; Lee K et al.; A chloramphenicol-resistant strain of Salmonella enterica serovar Typhi was first noted in Korea in 1992, when a resistant isolate was detected in a returned traveler . Continued isolation of multidrug-resistant (MDR) strains thereafter in other settings prompted a retrospective analysis of laboratory records and phenotypic and genotypic analyses of 12 chloramphenicol-resistant isolates . Among these, one isolate was resistant only to chloramphenicol, and the other isolates were also resistant to ampicillin and co-trimoxazole . MDR was transferred by conjugation from 9 of the 11 isolates . PCR showed that all isolates had an incompatible group HI1 plasmid, and oriT was detected in 10 isolates, which included strains with an unsuccessful transfer of resistance . All of the ampicillin-resistant isolates had a beta-lactamase band of pI 5.4 and bla(TEM) alleles . A PCR amplicon from an isolate showed that the sequences were identical to those of bla(TEM-1), suggesting that all isolates had a TEM-1 beta-lactamase . All isolates had class 1 integrons: 10 isolates had integrons of ca . 1.2 kb with dhfr7 gene cassettes, and 1 isolate had an integron of ca . 2.3 kb with aacA4 and bla(OXA-1)-like gene cassettes . The pulsed-field gel electrophoresis patterns of 7 of 11 MDR isolates were identical and indistinguishable from those reported for isolates in India and Indonesia . In conclusion, some of the MDR strains in Korea are related to those in other Asian countries . Susceptibility testing became necessary for selection of antimicrobial agents for the optimal treatment of patients with the emergence of MDR Salmonella serovar Typhi in Korea.

Emerg Infect Dis, 2004 Oct, 10(10), 1782 - 9
Egg quality assurance programs and egg-associated Salmonella enteritidis infections, United States; Mumma GA et al.; A Salmonella enterica serovar Enteritidis epidemic in the United States began in 1978, spread to much of the country in the following decade, and began declining in 1996 . We examined correlations between annual changes in S . Enteritidis incidence in humans and introductions of egg quality assurance programs (EQAPs) in some states to reduce S . Enteritidis contamination of eggs . Before EQAPs, 62% of the changes in S . Enteritidis incidence were higher than the baseline for each state . After EQAPs, 73%-84% of the changes were below the baseline . Regression analysis showed that a 1% increase in the number of eggs produced under an EQAP was associated with a 0.14% decrease in S . Enteritidis incidence (p < 0.05) . These data indicate that EQAPs probably played a major role in reducing S . Enteritidis illness in these states.

Planta Med, 2004 Sep, 70(9), 841 - 6
Phenolic compounds from Baseonema acuminatum leaves: isolation and antimicrobial activity; De Leo M et al.; Three new phenolic compounds, 1-galloyl-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside (1), 2-methoxy-5-(1 '2 3'-trihydroxypropyl)-phenyl- 1-0-(6"-galloyl)-beta-D-glucopyranoside (2),and 2-methoxy-5-hydroxymethyl-phenyl-1-O-(6"-galloyl)-beta-D-glucopyranoside (3), together with the known compounds benzyl 6'-O-galloyl-beta-D-glucopyranoside (4), 1,6-di-O-galloyl-beta-D-glucopyranose (5), myrciaphenone B (6), kaempferol 3-0-(6"-galloyl)-beta-D-glucopyranoside (7), quercetin 3-0-(6"-galloyl)-beta-D-glucopyranoside (8), vomifoliol 9-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside, 2,3-dihydrobenzofuran-2-(4'-hydroxy-3'-methoxyphenyl)-3-alpha-L-rhamnopyranosyloxymethyl-7-methoxy-5-propanol, and benzyl-O-alpha-L-rhamnopyranosyl-(1-->6)-Beta-D-glucopyranoside were isolated from the leaves of Baseonema acuminatum P . Choux (Asclepiadaceae) . Their structures were determined by 1D- and 2D-NMR spectroscopy and by ESI-MS analysis . The antimicrobial activity of all compounds was evaluated in vitro against bacteria (Staphylococcus aureus two strains, Bacillus cereus, Bacillus subtilis, Escherichia coli, Salmonella thyphimurium) and three strains of Candida albicans . The new compounds 2 and 3, together with the known compound 4, showed antifungal activity against two clinically isolated Candida albicans strains and against C . albicans ATCC 2091; MIC values were in the range of 25-100 microg/mL . Compound 5 was active against the two clinically isolated strains of C . albicans with MICs of 12.5 microg/mL and 25 microg/mL . Compounds 1, 6, 7, and 8 inhibited only one strain of C albicans at the maximum concentration used . None of the phenolic compounds tested was active against the bacteria studied.

Mol Genet Genomics . 2004 Oct 16; {Epub ahead of print}
Virulence regulators RfaH and YaeQ do not operate in the same pathway; Vicari D et al.; The expression of virulence factors such as hemolysin and lipopolysaccharides in Proteobacteria is regulated by the transcription elongation factor RfaH . RfaH reduces pausing and termination at intergenic sites, and thus allows RNA polymerase to conclude transcription of the distal genes in long virulence operons . The yaeQ gene of Salmonella enterica sv . Typhimurium has been identified as a high-copy-number suppressor of the hemolytic defect in an rfaH deletion strain, leading to speculation regarding a direct role of YaeQ in the transcriptional control of bacterial virulence . In order to evaluate this hypothesis, yaeQ genes from Escherichia coli and S . enterica sv . Typhimurium were cloned and expressed . Their products, purified YaeQ proteins, displayed no antitermination effects in in-vitro transcription assays over a wide range of concentrations, neither by themselves nor in competition with RfaH . When overexpressed in vivo , plasmid-borne E . coli and S . enterica sv . Typhimurium yaeQ genes also failed to restore hemolytic activity in an rfaH deletion strain under conditions in which episomal E . coli rfaH and its orthologs exhibited full complementation of the genomic rfaH deletion . Taken together, our findings do not support the hypothesis of YaeQ involvement in RfaH-dependent regulation of virulence, even in stoichiometric excess in vitro or upon overexpression in vivo.

Infect Immun, 2004 Nov, 72(11), 6546 - 53
Enhanced immunogenicity in the murine airway mucosa with an attenuated Salmonella live vaccine expressing OprF-OprI from Pseudomonas aeruginosa; Arnold H et al.; We constructed an oral live vaccine based on the attenuated aroA mutant Salmonella enterica serovar Typhimurium strain SL3261 expressing outer membrane proteins F and I (OprF-OprI) from Pseudomonas aeruginosa and investigated it in a mouse model . Strains with in vivo inducible protein expression with the PpacC promoter showed good infection rates and immunogenicity but failed to engender detectable antibodies in the lung . However, a systemic booster vaccination following an oral primary immunization yielded high immunoglobulin A (IgA) and IgG antibody levels in both upper and lower airways superior to conventional systemic or mucosal booster vaccination alone . In addition, the proportion of IgG1 and IgG2a antibodies suggested that the systemic booster does not alter the more TH1-like type of response induced by the oral Salmonella primary vaccination . We conclude that an oral primary systemic booster vaccination strategy with an appropriate mucosal vector may be advantageous in diseases with the risk of P . aeruginosa airway infection, such as cystic fibrosis.

Infect Immun, 2004 Nov, 72(11), 6390 - 400
In vivo compartmentalization of functionally distinct, rapidly responsive antigen-specific T-cell populations in DNA-immunized or Salmonella enterica serovar Typhimurium-infected mice; Kirby AC et al.; The location and functional properties of antigen-specific memory T-cell populations in lymphoid and nonlymphoid compartments following DNA immunization or infection with Salmonella were investigated . Epitope-specific CD8+ -T-cell expansion and retention during the memory phase were analyzed for DNA-immunized mice by use of a 5-h peptide restimulation assay . These data revealed that epitope-specific gamma interferon (IFN-gamma)-positive CD8+ T cells occur at higher frequencies in the spleen, liver, and blood than in draining or peripheral lymph nodes during the expansion phase . Moreover, this distribution is maintained into long-term memory . The location and function of both CD4+ and CD8+ Salmonella-specific memory T cells in mice who were given a single dose of Salmonella enterica serovar Typhimurium was also quantitated by an ex vivo restimulation with bacterial lysate to detect the total Salmonella-specific memory pool . Mice immunized up to 6 months previously with S . enterica serovar Typhimurium had bacterium-specific CD4+ T cells that were capable of producing IFN-gamma or tumor necrosis factor alpha (TNF-alpha) at each site analyzed . Similar findings were observed for CD8+ T cells that were capable of producing IFN-gamma, while a much lower frequency and more restricted distribution were associated with TNF-alpha-producing CD8+ T cells . This study is the first to assess the frequencies, locations, and functions of both CD4+ and CD8+ memory T-cell populations in the same Salmonella-infected individuals and demonstrates the organ-specific functional compartmentalization of memory T cells after Salmonella infection.

Infect Immun, 2004 Nov, 72(11), 6294 - 9
Respiratory hydrogen use by Salmonella enterica serovar Typhimurium is essential for virulence; Maier RJ et al.; Based on available annotated gene sequence information, the enteric pathogen salmonella, like other enteric bacteria, contains three putative membrane-associated H2-using hydrogenase enzymes . These enzymes split molecular H2, releasing low-potential electrons that are used to reduce quinone or heme-containing components of the respiratory chain . Here we show that each of the three distinct membrane-associated hydrogenases of Salmonella enterica serovar Typhimurium is coupled to a respiratory pathway that uses oxygen as the terminal electron acceptor . Cells grown in a blood-based medium expressed four times the amount of hydrogenase (H2 oxidation) activity that cells grown on Luria Bertani medium did . Cells suspended in phosphate-buffered saline consumed 2 mol of H2 per mol of O2 used in the H2-O2 respiratory pathway, and the activity was inhibited by the respiration inhibitor cyanide . Molecular hydrogen levels averaging over 40 microM were measured in organs (i.e., livers and spleens) of live mice, and levels within the intestinal tract (the presumed origin of the gas) were four times greater than this . The half-saturation affinity of S . enterica serovar Typhimurium for H2 is only 2.1 microM, so it is expected that H2-utilizing hydrogenase enzymes are saturated with the reducing substrate in vivo . All three hydrogenase enzymes contribute to the virulence of the bacterium in a typhoid fever-mouse model, based on results from strains with mutations in each of the three hydrogenase genes . The introduced mutations are nonpolar, and growth of the mutant strains was like that of the parent strain . The combined removal of all three hydrogenases resulted in a strain that is avirulent and (in contrast to the parent strain) one that is unable to invade liver or spleen tissue . The introduction of one of the hydrogenase genes into the triple mutant strain on a low-copy-number plasmid resulted in a strain that was able to both oxidize H2 and cause morbidity in mice within 11 days of inoculation; therefore, the avirulent phenotype of the triple mutant is not due to an unknown spurious mutation . We conclude that H2 utilization in a respiratory fashion is required for energy production to permit salmonella growth and subsequent virulence during infection.

Bioresour Technol, 2005 Mar, 96(5), 587 - 95
Isolation of Salmonella spp . from liquid and solid excreta prior to and following ensilage in ten swine farms located in central Mexico; Ramirez G et al.; A study was carried out to define selected bacteriological characteristics of residues from 10 swine farms, 5 with or without prior clinical enteric disease (PCED) and to determine the effect of ensilage on the bacteria present in the solid fraction . At each farm, samples were taken from the sedimentation basin (SB), the solid fraction (SF), and the liquid fraction (LF) . For each sample, CFU/g for enteric bacteria were quantified; Salmonella spp . were isolated and typified . Solid phase samples from each farm were used to prepare the ensilage, with a mixture of solids (80%), sorghum (12%) and molasses (8%) . The quantity of enteric bacteria was significantly greater in farms without PCED (P<0.05) . Salmonella enterica were isolated from 8/10 of the farms with and without PCED; in 8 from SB; in 6 from LF; and in 5 from SF . Enteric bacteria were not isolated from silage, therefore, ensilage may be an alternative treatment for excreta that allows the elimination of pathogens such as Salmonella spp.

Life Sci, 2004 Nov 19, 76(1), 85 - 101
Antigenotoxic properties of Cassia tea (Cassia tora L.): mechanism of action and the influence of roasting process; Wu CH et al.; Antigenotoxic properties and the possible mechanisms of water extracts from Cassia tora L . (WECT) treated with different degrees of roasting (unroasted and roasted at 150 and 250 degrees C) were evaluated by the Ames Salmonella/microsome test and the Comet assay . Results indicated that WECT, especially unroasted C . tora (WEUCT), markedly suppressed the mutagenicity of 2-amino-6-methyldipyrido(1,2-a:3':2'-d)imidazole (Glu-P-1) and 3-amino-1,4-dimethyl-5H-pyrido(4,3-b)indole (Trp-P-1) . In the Comet assay performed on human lymphocytes, WECT exhibited significant protective effect on Trp-P-1-mediated DNA damage followed the order of unroasted (55%) > roasted at 150 degrees C (42% ) > roasted at 250 degrees C (29%) . Pre-treatment of the lymphocytes with WEUCT resulted in 30% repression of DNA damage . However, no significant effect on excision-repair system was found during DNA damage expression time in post-treatment scheme (p>0.05) . WEUCT showed 84% scavenging effect on oxygen free radicals generated in the activation process of mutagen detected by electron paramagentic resonance system . Two possible mechanisms were considered: (1) neutralization the reactive intermediate of Trp-P-1; and (2) protecting cells directly as an antioxidant that scavenge the oxygen radicals from the activation process of mutagen . The individual anthraquinone content in extracts of C . tora was measured by HPLC . Three anthraquinones, chrysophanol, emodin and rhein, have been detected under experimental conditions . The anthraquinone content decreased with increased roasting temperature . Each of these anthraquinones demonstrated significant antigenotoxicity against Trp-P-1 in the Comet assay . In conclusion, our data suggest that the decrease in antigenotoxic potency of roasted C . tora was related to the reduction in their anthraquinones.

J Infect Dis, 2004 Nov 15, 190(10), 1755 - 7 Epub 2004 Oct 07.
Interleukin (IL)-12 and IL-23 are key cytokines for immunity against Salmonella in humans; MacLennan C et al.; Patients with inherited deficiency of the interleukin (IL)-12/IL-23-interferon (IFN)- gamma axis show increased susceptibility to invasive disease caused by the intramacrophage pathogens salmonellae and mycobacteria . We analyzed data on 154 patients with such deficiency . Significantly more patients with IL-12/IL-23-component deficiency had a history of salmonella disease than did those with IFN- gamma -component deficiency . Salmonella disease was typically severe, extraintestinal, and caused by nontyphoidal serovars . These findings strongly suggest that IL-12/IL-23 is a key cytokine for immunity against salmonella in humans and that IL-12/IL-23 mediates this protective effect partly through IFN- gamma -independent pathways . Investigation of the IL-12/IL-23-IFN- gamma axis should be considered in patients with invasive salmonella disease.

Cancer Gene Ther, 2005 Jan, 12(1), 101 - 8
Positron emission tomography (PET) imaging of tumor-localized Salmonella expressing HSV1-TK; Soghomonyan SA et al.; In order to noninvasively detect Salmonella delivery vectors within tumors, we used a genetically modified Salmonella, VNP20009, that expresses the herpes simplex thymidine kinase (HSV1-tk) reporter gene . VNP20009-TK were able to selectively localize within murine tumor models and to effectively sequester a radiolabeled nucleoside analogue, 2'-fluoro-1-beta-D-arabino-furanosyl-5-iodo-uracil (FIAU) . A quantitative relationship between the level of radioactivity accumulated and the number of bacteria in tumor and different tissues was demonstrated . The in vivo accumulation of {14C}FIAU measured in tissue sample homogenates and sections were related to Salmonella number and to immunohistochemical bacterial staining, respectively . Quantitative autoradiography (QAR) revealed the relative intensity of {14C}FIAU accumulation in a tumor cross-section, demonstrating that the peripheral region of the tumor was significantly less active than internal regions . {124I}FIAU positron emission tomography (PET) and subsequent tissue radioactivity and bacterial concentration measurements were compared . A log-log relationship was found, and the PET images could identify multiple tumor sites . The ability to noninvasively detect Salmonella vectors by PET imaging has the potential to be conducted in a clinical setting, and could aid in development of these vectors by demonstrating the efficiency and duration of targeting as well as indicating the locations of tumors.

Emerg Infect Dis, 2004 Sep, 10(9), 1674 - 6
Fluoroquinolone resistance in Salmonella enterica serotype Choleraesuis, Taiwan, 2000-2003; Chiu CH et al.; Salmonella enterica serotype Choleraesuis is a highly invasive pathogen that infects humans and causes systemic infections that require antimicrobial therapy . Surveillance in Taiwan showed that fluoroquinolone resistance in S . Choleraesuis markedly increased from 2000 to 2003, reaching approximately 70% in 2003.

Emerg Infect Dis, 2004 Sep, 10(9), 1665 - 7
Salmonella enterica serotype Uganda infection in New York City and Chicago; Jones RC et al.; Outbreaks associated with distinct strains of Salmonella enterica serotype Uganda, a rare serotype, occurred in New York City and Chicago during the summer of 2001 . Both outbreaks were linked to eating ready-to-eat pork products . This serotype may emerge as a more frequent cause of human infections.

Saudi Med J, 2004 Oct, 25(10), 1486 - 8
Salmonellosis and ulcerative colitis . A causal relationship or just a coincidence; Karaoglu AO et al.; Coincidence of salmonellosis and ulcerative colitis is a rare clinical problem . Salmonella infection was reported to complicate the ulcerative colitis, as either facilitating its occurrence or activation . In this article, we present a case with salmonellosis whose clinicopathological findings also suggested ulcerative colitis . The patient improved rapidly after taking additional mesalazine to norfloxacin treatment . We conclude that salmonella infection might have either been coincidentally present or might have triggered an early ulcerative colitis in this patient who did not have history of inflammatory bowel diseases . In case of persistent severe diarrhea despite appropriate treatment, the possibility of a coincident inflammatory bowel disease such as ulcerative colitis should always be considered, especially in endemic regions for salmonellosis.

J Immunol, 2004 Nov 1, 173(9), 5852 - 62
Identification of a human HLA-E-restricted CD8+ T cell subset in volunteers immunized with Salmonella enterica serovar Typhi strain Ty21a typhoid vaccine; Salerno-Goncalves R et al.; Our previous studies in volunteers immunized with Salmonella enterica serovar Typhi (S . Typhi) have suggested an important role for CD8+ T cells in host defense . In this study we describe a novel subset of nonclassical human HLA-E-restricted S . Typhi-specific CD8+ T cells derived from PBMC of Ty21a typhoid vaccinees . CD3+CD8+CD4-CD56- T cells effectively killed S . Typhi-infected targets regardless of whether they share classical HLA class I molecules with them, by a FAS-independent, granule-dependent mechanism, as evidenced by induction of granzyme B release and the blocking effects of concanamycin and strontium ions . The expression of HLA-E Ags, but not CD1-a, -b, or -c, on the membrane of S . Typhi-infected targets rendered them susceptible to lysis . Moreover, anti-HLA-E Abs partially blocked these responses . We also demonstrated that presentation of S . Typhi Ags via HLA-E could stimulate IFN-gamma production . Increases in the net frequency of IFN-gamma spot-forming cells were observed in the presence of targets coated with peptides that contain S . Typhi GroEL HLA-E binding motifs . These results demonstrate that HLA-E binds nonamer peptides derived from bacterial proteins and trigger CD8+-mediated lysis and IFN-gamma production when exposed to infected targets, raising the possibility that this novel effector mechanism might contribute to host defense against intracellular bacterial infections.

Int J Med Microbiol, 2004 Sep, 294(2-3), 95 - 102
Evolution of pathogenicity islands of Salmonella enterica; Hensel M; Virulence genes located on pathogenicity islands play a crucial role in the pathogenesis of Salmonella enterica infections . Salmonella pathogenicity islands (SPI) contribute to host cell invasion and intracellular pathogenesis . At present, 12 SPI have been described . Although size, structure and function of these SPI, as well as the distribution in Salmonella subspecies and serovars can be markedly different, several common motifs are present among SPI . In this review, the characteristics of SPI are described with focus on the evolution of these genetic elements.

Acta Paediatr Taiwan, 2004 May-Jun, 45(3), 163 - 7
X-linked chronic granulomatous disease: report of one case; Weng JD et al.; Chronic granulomatous disease (CGD) is an inherited dysfunction of phagocytic cells secondary to a defect in the respiratory burst to kill catalase-positive microorganisms . This leads to recurrent life-threatening bacterial and fungal infections . We report a 1 year-10 month-old boy with X-linked CGD who was noted to have recurrent suppurative lymphadenitis since one and half month old . Failure to thrive, lymphadenitis and generalized skin lesions with multiple scar and dimples were found . Immunological data of patient, his mother and father were as follows: PMN phagocytosis (%): 98, 88, 92 (control, >80), PMN chemotaxis: 0.6, 1.0, 1.3 (control, >1.2), PMN bactericidal function test over a period of 2 hours (%): 28.1, 28.5, 84.8 (control, 82.1) . PMN chemiluminescence (delta mV): 0.612, 364.1, 1131 (control, 614.1), H202 production (ug/mL): 1.6, 7.2, 16.8 (control, 14.1), NBT test: negative, mixed, positive (control, positive) . His mother was a carrier . The patient expired with invasive salmonella infection before the availability of gamma-interferon prophylaxis.

J Reprod Med, 2004 Sep, 49(9), 762 - 4
Ovarian abscess from Salmonella: a case report; Chin HY et al.; BACKGROUND: An ovarian site of Salmonella bacteremia is rare . The contents of a teratoma may hide the organisms easily . Clinicians should be alert to this possibility when the patient had a teratoma with Salmonella infection . CASE: A 19-year-old woman presented with a missed menstrual period . An adnexal mass was found during a routine gynecologic examination . The patient had had gastroenteritis 2 months earlier but did not complain of a gastrointestinal problem at presentation . Exploratory laparotomy was performed for a suspected ovarian tumor . An infective teratoma was considered, but the infection source was unknown until the culture report showed a Salmonella infection . CONCLUSION: Salmonella infection is a self-limiting, febrile disease and is unlikely to involve organs other than the gut . A nontyphoid ovarian abscess became a rare late complication of acute gastroenteritis . Clinicians should pay special attention to the differential diagnosis of ovarian tumor in patients with a history of Salmonella infection, especially those with such ovarian lesions as endometrioma or teratoma and with recent abdominal pain, as noted in this case.

Acta Pol Pharm, 2004 Mar-Apr, 61(2), 123 - 5
Antimicrobial effect of Cu(II) complexes containing oxime ligands; Donde KJ et al.; The antibacterial, antifungal and antitubercular activity of Cu(II) complexes was studied . All the complexes have been screened against Staphylococcus aureus, Salmonella typhi, Candida albican, Aspergillus niger, Saccharomyces cerevisiae and H37Rv and found to be more toxic than the parent ligand . The activity increased in the order Cu(5-methyl-2,3-hexanedione dioxime)2 < Cu(5-methyl-3-oximino-hexan-2-o-ne-hydrazone)2 < Cu(5-methyl-3-oximino-hexan-2-one-phenylhydrazone)2.

Mol Microbiol, 2004 Nov, 54(3), 823 - 35
The response regulator SsrB activates transcription and binds to a region overlapping OmpR binding sites at Salmonella pathogenicity island 2; Feng X et al.; OmpR activates expression of the two-component regulatory system located on Salmonella pathogenicity island 2 (SPI-2) that controls the expression of a type III secretion system, as well as many other genes required for systemic infection in mice . Measurements of SsrA and SsrB protein levels under different growth conditions indicate that expression of these two components is uncoupled, i.e . SsrB is produced in the absence of ssrA and vice versa . This result was suggested from our previous studies, in which two promoters at ssrA/B were identified . The isolated C-terminus of SsrB binds to DNA and protects regions upstream of ssrA, ssrB and srfH from DNase I digestion . Furthermore, the C-terminus of SsrB alone is capable of activating transcription in the absence of the N-terminus . Results from beta-galactosidase assays indicate that the N-terminal phosphorylation domain inhibits the C-terminal effector domain . A previous study from our laboratory reported that ssrA-lacZ and ssrB-lacZ transcriptional fusions were substantially reduced in an ssrB null strain . Results from DNase I protection assays provide direct evidence that SsrB binds at ssrA and ssrB, although the binding sites lie within the transcribed regions . Additional regulators clearly affect gene expression at this important locus, and here we provide evidence that SlyA, a transcription factor that contributes to Salmonella virulence, also affects ssrA/B gene expression.

Mol Microbiol, 2004 Nov, 54(3), 702 - 14
Metabolic differentiation in actively swarming Salmonella; Kim W et al.; Most current paradigms of microbial metabolism have been derived from studying cells grown under a variety of nutrient compositions in aqueous environments . With recent advances in genomics and experimental techniques, alternative forms of bacterial growth are increasingly being explored . When propagated on nutrient-rich semi-solid media, several species of bacteria undergo a morphological differentiation into swarmers that are capable of migrating on surfaces . Recent studies indicate that swarmer differentiation represents much more than a motility phenotype, as several clinically important attributes are also co-regulated . We demonstrate that migrating swarmer cells of Salmonella are metabolically differentiated compared to the vegetative swimmer cells grown in the same nutrient environment . Furthermore, once the cells have differentiated, the swarmers remain in this physiological state under conditions that do not promote the initial differentiation . The bacterium's capacity to override some of the classic paradigms of metabolic regulation established in aqueous environments represents a unique physiological response by the pathogen that may be advantageous in polymicrobial environments such as the host.

Mol Microbiol, 2004 Nov, 54(3), 604 - 19
SsaM and SpiC interact and regulate secretion of Salmonella Pathogenicity Island 2 type III secretion system effectors and translocators; Yu XJ et al.; The type III secretion system (TTSS) encoded by Salmonella Pathogenicity Island 2 (SPI-2) is required for systemic infection and intracellular replication of Salmonella enterica serovar Typhimurium . The SPI-2 TTSS is activated after internalization of bacteria by host cells, and translocates effector proteins into and across the vacuolar membrane, where they interfere with several host cell functions . Here, we investigated the function of SsaM, a small protein encoded within SPI-2 . An ssaM deletion mutant had virulence and intracellular replication defects comparable to those of a SPI-2 TTSS null mutant . Although the ssaM mutant was able to secrete the effector protein SseJ in vitro, it failed to translocate SseJ into host cells, and to secrete the translocon proteins SseB, SseC and SseD in vitro . This phenotype is similar to that of a strain carrying a mutation in the SPI-2 gene spiC, whose product is reported to be an effector involved in trafficking of the Salmonella vacuole in macrophages . Both ssaM and spiC mutants were found to oversecrete the SPI-2 effector proteins SseJ and PipB in vitro . Fractionation assays and immunofluorescence microscopy were used to investigate the localization of SsaM and SpiC in macrophages . No evidence for translocation of these proteins was obtained . The similar phenotypes of the ssaM and spiC mutants suggested that they might be involved in the same function . Pull-down and co-immune precipitation experiments showed that SpiC and SsaM interact within the bacterial cell . We propose that a complex involving SsaM and SpiC distinguishes between translocators and effector proteins, and controls their ordered secretion through the SPI-2 TTSS.

Afr J Med Med Sci, 2004 Mar, 33(1), 69 - 72
Changing patterns in sensitivity of causative organisms of septicaemia in children: the need for quinolones; Orogade AA et al.; A review of the pattern, and antibiotic sensitivities of blood culture isolates over a 3 year period in children presenting to the Paediatric Unit of Ahmadu Bello University Teaching Hospital, Kaduna is reported . Positive blood culture isolates were obtained in 26.9% of 1,982 children . The most prevalent isolates were Staphylococcus aureus (59.9%), Escherichia coli (16.9%) and Klebsiella (16.3%) . There was a striking paucity of isolation of Salmonella typhi (1.3%) and Streptococcus . Sensitivity to commonly used drugs like ampicillin/cloxacillin, genticin, ceftazidime and chloramphenicol was low (8.0-50.0%), with a corresponding delayed fever resolution and prolonged hospital stay . 31.0-83.3% of the isolates were highly sensitive to pefloxacin, norfloxacin and ofloxacin, which were not generally recommended for use in paediatric patients . In two patients with no response to commonly used antibiotics, use of quinolones lysed their fever within 48 hours . This change of antibiotic sensitivity patterns calls for a thorough investigation into the potential role of these quinolones in paediatric chemotherapeutics either singly or in appropriate combinations with existing antibiotics.

East Afr Med J, 2004 Jul, 81(7), 358 - 61
Salmonellae carrier status of food vendors in Kumasi, Ghana; Feglo PK et al.; OBJECTIVE: To determine the prevalence of chronic typhoidal salmonellae amongst food vendors in Kumasi Ghana . DESIGN: A prospective study . SETTING: Sitting and itinerant food vendors in Kumasi . METHODS: Screening of 258 (230 females of 28 males) healthy food vendors for Salmonella typhi, and S . paratyphi A, B, and C, using stool culture, the widal test, and standard microbiological identification methods . MAIN OUTCOME MEASURES: Prevalence of chronic typhoidal Salmonellae carriers among food vendors in Kumasi . RESULTS: Typhoidal Salmonellae were isolated from six people, giving a carriage rate of 2.3% . Three of the Salmonellae isolated were S . typhi, and they had significant Widal agglutinin titres of > or = 1/160 and > or = 1/320 for 0 and H antigens, respectively . The other three were non-typhoidal Salmonellae . The three had S . typhi and the other three had titres of 1/80 or less for both 0 and H antigens, respectively . We have discussed the implications of this high carriage rate, and we have suggested the inclusion of screening for Salmonellae of the regular health screening exercise undertaken by food handlers to detect and monitor chronic carriers in the food industry, to help control salmonella diseases in the community . CONCLUSION: From our study, food handlers consitute a significant risk in the spread of enteric fever in Kumasi . We therefore, suggest the inclusion of screening for Salmonellae in the regular obligatory six-monthly examination required of food handlers and to monitor those found to be infected.

Microbes Infect, 2004 Nov, 6(13), 1205 - 11
Re-structuring the host cell: up close with Salmonella's molecular machinery; Lilic M et al.; A common theme in bacterial disease is the manipulation of the eukaryotic cytoskeleton by pathogenic factors . Understanding how virulence factors operate to achieve these alterations is a growing and important research effort . This review focuses on several virulence factors from the pathogen Salmonella, and considers the contributions of structural biology to our appreciation of bacterial modulation of cytoskeletal dynamics.

Trends Microbiol, 2004 Nov, 12(11), 476 - 82
An analysis of type-III secretion gene clusters in Chromobacterium violaceum; Betts HJ et al.; Chromobacterium violaceum is an environmental Gram-negative bacterium that is common in soil and water in tropical and sub-tropical regions . It is also a model organism for studying quorum-sensing and is a rare but deadly human pathogen . Recent completion of the genome sequence of C . violaceum strain ATCC 12472 revealed the presence of genes associated with type-III secretion systems (TTSSs) . One of these systems resembles the Spi-1 system found in Salmonella enterica, whereas another is similar to the Spi-2 system from the same organism . Here, we present a detailed analysis and a fresh annotation of the two gene clusters . Moreover, we highlight the presence of several genes encoding putative type-III effector proteins that lead us to predict that this organism can manipulate vesicular trafficking, the actin cytoskeleton and apoptotic pathways within mammalian cells to its own advantage.

Mol Cell Probes, 2004 Dec, 18(6), 409 - 20
Comparison of PCR-ELISA and LightCycler real-time PCR assays for detecting Salmonella spp . in milk and meat samples; Perelle S et al.; In a previous study, we reported the performance of a PCR assay amplifying 285-bp of the invA gene of Salmonella spp . through an international ring-trial involving four participating laboratories {Int . J . Food Microbiol . 89 (2003) 241} . Based on the validated set of primers and recent advancements in PCR technology, we have designed two specific PCR assays for detecting Salmonella spp . We have compared PCR-enzyme-linked immunosorbent assay (PCR-ELISA) and LightCycler real-time PCR assay (LC-PCR) with the standard ISO 6579 bacteriological reference method . The two PCR tests incorporated an internal amplification control (IAC) co-amplified with the invA gene of Salmonella to monitor potential PCR inhibitors and ensure successful amplification . The selectivity study involved 84 Salmonella and 44 non-Salmonella strains and the samples tested were represented by 60 artificially-contaminated samples of fish, minced beef and raw milk, and 92 naturally-contaminated milk and meat samples . When using either PCR-ELISA or LC-PCR assays, only Salmonella strains were detected . PCR-ELISA and LC-PCR assays gave with pure Salmonella cultures the same detection limit level of 10(3)CFU/ml, which corresponds respectively to 50 and 10 cells per PCR tube . Data on artificially contaminated samples indicated that both PCR methods were able to detect after enrichment less than five Salmonella cells in 25 g of food, giving 100% concordance with the ISO 6579 reference method . The results on naturally contaminated samples demonstrated that despite certain inhibition problems, LC-PCR and PCR-ELISA assays were highly specific and sensitive, and provide a powerful tool for detection of Salmonella in food samples.

J Microbiol Methods, 2004 Dec, 59(3), 337 - 49
Comparison of real-time PCR methods for detection of Salmonella enterica and Escherichia coli O157:H7, and introduction of a general internal amplification control; Klerks MM et al.; The objectives of this study were to compare different real-time PCR-based methods for detection of either Salmonella spp . or E . coli O157:H7 with respect to sensitivity, precision and accuracy . In addition, a general internal amplification control (IAC) is presented, allowing prevention of false negative results . The IAC allows insight in amplification efficiency and enables a more accurate quantification with the evaluated real-time PCR methods . Implementation of the IAC with the different PCR methods did not affect the precision of the methods, but the sensitivity was reduced 10-fold . Introduction of an IAC with the Salmonella enterica specific detection method showed a shift in Ct-value (increase of target Ct-value with 0.45+/-0.17 cycles), while with the method to detect E . coli O157:H7 no influence of IAC co-amplification was observed . The quantification threshold of the methods in which the IAC was included was determined at 1 pg of target DNA (equal to 200 CFU) per reaction . Qualitative detection was feasible down to 10 fg of target DNA per reaction using both methods in which the IAC was incorporated . The adjusted methods have the potential to provide fast and sensitive detection of Salmonella spp . or E . coli O157:H7, enabling accurate quantification and preventing false negative results by using the general IAC.

J Biol Chem, 2004 Dec 31, 279(53), 55707 - 14 Epub 2004 Oct 13.
Identification of a new member of the phage shock protein response in Escherichia coli, the phage shock protein G (PspG); Lloyd LJ et al.; The phage shock protein operon (pspABCDE) of Escherichia coli is strongly up-regulated in response to overexpression of the filamentous phage secretin protein IV (pIV) and by many other stress conditions including defects in protein export . PspA has an established role in maintenance of the proton-motive force of the cell under stress conditions . Here we present evidence for a new member of the phage shock response in E . coli . Using transcriptional profiling, we show that the synthesis of pIV in E . coli leads to a highly restricted response limited to the up-regulation of the psp operon genes and yjbO . The psp operon and yjbO are also up-regulated in response to pIV in Salmonella enterica serovar Typhimurium . yjbO is a highly conserved gene found exclusively in bacteria that contain a psp operon but is physically unlinked to the psp operon . yjbO encodes a putative inner membrane protein that is co-controlled with the psp operon genes and is predicted to be an effector of the psp response in E . coli . We present evidence that yjbO expression is driven by sigma(54)-RNA polymerase, activated by PspF and integration host factor, and negatively regulated by PspA . PspF specifically regulates only members of the PspF regulon: pspABCDE and yjbO . We found that increased expression of YjbO results in decreased motility of bacteria . Because yjbO is co-conserved and co-regulated with the psp operon and is a member of the phage shock protein F regulon, we propose that yjbO be renamed pspG.

Commun Dis Public Health, 2004 Sep, 7(3), 184 - 90
Microbiological quality of pre-cut fruit, sprouted seeds, and unpasteurised fruit and vegetable juices from retail and production premises in the UK, and the application of HAACP; Little CL et al.; A study of ready-to-eat pre-cut fruit, sprouted seeds, and unpasteurised fruit and vegetable juices from retail and production premises was undertaken in the UK to determine the microbiological quality of these products, and to verify the application of hazard analysis and critical control points (HACCP) procedures by food operators . Almost all (99%; 2,075/2,096) samples were of satisfactory/acceptable microbiological quality . Two (0.1%) samples (melon, beansprouts) were of unacceptable quality due to the presence of Listeria monocytogenes at 102 cfu/g or more while a further 19 (0.9%) were unsatisfactory due to Escherichia coli levels in the range of 102 to 106 cfu/g . Neither Salmonella spp . nor E . coli O157 were detected in samples examined . A hazard analysis system was in place in most (85%) premises visited, and in 80% it was documented . Most managers (83%) had received some form of food hygiene training . Minimally processed produce is exposed to a range of conditions during production and distribution, and this may increase the potential for microbial contamination, highlighting the need of applying good hygiene practices from farm to fork to prevent contamination and/or bacterial growth . Such products should be stored and displayed at or below 8 degrees C.

Kansenshogaku Zasshi, 2004 Aug, 78(8), 690 - 8
{Epidemiological analysis of Salmonella enteritidis isolates using pulsed-field gel electrophoresis and bacteriophage typing over the period of April 2000 to March 2003 in Gifu Prefecture}; Itagaki M et al.; We examined a total of 151 Salmonella enterica serovar Enteritidis strains isolated in Gifu Prefecture during the period from April 2000 to March 2003 by using bacteriophage typing and pulsed-field gel electrophoresis (PFGE) . Bacteriophage typing classified them into twelve phage types (PT) and RDNC (reacted but did not conform) . The predominant phage type was PT47 (34.4%) followed by PT1 (21.9%), PT4 (16.6%) and RDNC (11.3%) . XbaI- and BlnI-digested PFGE analyses identified 17 and 44 PFGE patterns, respectively, indicating that PFGE with BlnI had more discriminating power than that with XbaI . Combination of the phage types and PFGE types of BlnI could make 53 subtypes . Some isolates with the same phage type were subdivided into different PFGE types, but those with PT47 were not . PT47 isolates were derived from sporadic patients with gastroenteritis, food poisoning outbreaks and healthy carriers through the years . This suggests that PT47 is highly clonal and disseminates over our prefecture.

Phytother Res, 2004 Aug, 18(8), 670 - 3
Antimicrobial evaluation of some medicinal plants for their anti-enteric potential against multi-drug resistant Salmonella typhi; Rani P et al.; Screening was done of some plants of importance in the Ayurvedic system of traditional medicine used in India to treat enteric diseases . Fifty four plant extracts (methanol and aqueous) were assayed for their activity against multi-drug resistant Salmonella typhi . Strong antibacterial activity was shown by the methanol extracts of Aegle marmelos, Salmalia malabarica, Punica granatum, Myristica fragrans, Holarrhena antidysenterica, Terminalia arjuna and Triphal (mixture of Emblica of fi cinalis, Terminalia chebula and Terminalia belerica) . Moderate antimicrobial activity was shown by Picorhiza kurroa, Acacia catechu, Acacia nilotica, Cichorium intybus, Embelia ribes, Solanum nigrum, Carum copticum, Apium graveolens, Ocimum sanctum, Peucedanum graveolens and Butea monosperma.

Environ Mol Mutagen, 2004, 44(4), 304 - 12
Cyclopenta{cd}fluoranthene and its precursors in combustion exhausts: a survey of their bacterial mutagenic activity; Otero-Lobato MJ et al.; Cyclopenta{cd}fluoranthene (1) and 3-ethynylfluoranthene (2) have both recently been identified in combustion exhausts . In this study, their mutagenic activities were compared to that of fluoranthene (3), one of the most abundant polycyclic aromatic hydrocarbons (PAHs) in combustion exhausts, in the Salmonella/microsome reversion assay (Ames assay) using S . typhimurium strain TA98 . The mutagenicity of 1 was modest in comparison to other active cyclopenta PAHs . Unexpectedly, 2 was mutagenic both with and without exogenous metabolic activation (rat liver S9) . Furthermore, cyclopenta{cd}fluoranthene-3,4-epoxide (6) was synthesized in order to evaluate its role as the ultimate mutagenic active form of 1 . The epoxide 6 was a direct-acting mutagen . In addition, a pyrolysate containing a mixture of 1 (85%), 2 (2%), and 3 (13%) obtained by flash vacuum thermolysis of 3-(1-chloroethenyl)fluoranthene (2a) at 1,050 degrees C was also mutagenic, but a significant mutagenic response was detected only in the presence of S9 activation . The results of this study indicate that 1 and 2 can contribute to the mutagenic activity of combustion exhausts.

J Infect, 2004 Nov, 49(4), 291 - 6
Genotypic diversity of Salmonella Enteritidis isolates from sporadic patients in limited area during one year; Seno M et al.; OBJECTIVES: Our aims were to investigate the genetic epidemiology of Salmonella enterica serovar Enteritidis (S . Enteritidis) isolates using computerized analysis of restriction enzyme cleavage patterns . METHODS: A total of 106 S . Enteritidis isolates which were collected in Hiroshima Prefecture, Japan in 2001 were tested by pulsed-field gel electrophoresis (PFGE) using BlnI and XbaI enzymes . PFGE profiles were analysed and compared by using Fingerprinting II software . RESULTS: BlnI PFGE analysis divided the isolates into 29 genotypes . At 90% similarity, BlnI cleavage grouped the isolates into 15 genotypes, while XbaI cleavage grouped them into only four . Two major clusters, each with a predominant genotype, were identified by BlnI cleavage at 42% similarity . In spite of the mixed circulation of the two predominant genotypes, one genotype for which a number of subtypes were detected was predominant during the first half of the year . In contrast, the other genotype, for which no variant subtypes were detected, followed during the latter half . The genotypes identified by computerized analysis matched well with those judged by visual inspection . CONCLUSIONS: The results confirmed the usefulness of PFGE performed with BlnI and of the Fingerprinting II software for the genotyping of S . Enteritidis . We think that the prevalent characteristics of the predominant genotypes detected here were related to the genetic variations of S . Enteritidis.

J Hosp Infect, 2004 Oct, 58(2), 122 - 7
A nosocomial outbreak of Salmonella enteritidis associated with lyophilized enteral nutrition; Matsuoka DM et al.; Outbreaks of Salmonella spp . gastro-enteritis in hospitals are of concern because of the increased susceptibility of patients and associated high morbidity . This study is a report of a nosocomial outbreak of Salmonella enteritidis associated with enteral nutrition . In December 1999, one sample of enteral feed tested positive for S . enteritidis . During the subsequent 6 weeks, eight cases of nosocomial salmonellosis occurred . Patients involved in the outbreak were aged 19-79 years (median = 36.5), and salmonella was isolated from the blood of two patients . All patients were receiving enteral nutrition at the time and all had diarrhoea . Three patients died . All 13 employees of the Nutrition Department were asymptomatic and their stool samples were negative . Environmental and water samples were also negative . The diet, however, contained lyophilized egg albumin . Molecular typing showed that the isolates of seven patients were indistinguishable from the one obtained from the enteral diet . It was thought that the nosocomial salmonellosis probably occurred due to the use of a commercial lyophilized diet . Another method of processing diets may be necessary to ensure patient safety.

Eur J Anaesthesiol, 2004 Aug, 21(8), 625 - 31
New approach to an ovine model of hypodynamic endotoxaemia; Westphal M et al.; BACKGROUND AND OBJECTIVE: Since the moribund hypodynamic phase of septic shock has primarily been studied in small animal models, the objective of this study was to investigate the usefulness of infusing Salmonella typhosa endotoxin at incrementing doses to establish an ovine model of hypodynamic endotoxaemia . METHODS: In a prospective laboratory experiment, eight adult ewes were instrumented for a chronic study . Following a baseline measurement in the healthy state, a continuous endotoxin infusion was started with 10 ng kg(-1) min(-1) and was doubled every hour seven times . Haemodynamics, key variables of oxygen transport, and arterial lactate concentrations were determined every hour . RESULTS: In a dose-dependent manner, endotoxin infusion caused pulmonary hypertension, decreased cardiac output and mean arterial pressure, increased heart rate, and to a certain extent, systemic vascular resistance index . Following 4h of endotoxaemia, the maximum decrease in cardiac output occurred (4.8+/-0.2 vs . 7.6+/-0.3 Lmin(-1); P < 0.001) . This was accompanied by tissue dysoxia, represented by decreases in oxygen delivery (797+/-20 vs . 1041+/-28 mLmin(-1)), oxygen consumption (277+/-14 vs . 396+/-15 mLmin(-1)) and oxygen extraction rate (0.35+/-0.01 vs . 0.38+/-0.01%; each P < 0.01), as well as an increase in arterial lactate concentration (1.7+/-0.1 vs . 0.7+/-0.1 mmolL(-1); P < 0.05) . CONCLUSIONS: This large animal model may be helpful to study the pathophysiology responsible for cardiovascular failure, and also new therapeutic approaches relevant to management of hypodynamic circulation in the common setting of progressed systemic inflammation.

Recenti Prog Med, 2004 Sep, 95(9), 414 - 7
{No floroquinolone resistance in non typhoidal salmonellas from hospitalized persons in an endemic area of Apulia, Italy}; Rollo MA et al.; Non typhi-salmonella is the most common cause of hospitalization or death associated with acute diarrhea . It is usually a self limiting disease and antibiotic therapy is not required, but in immunocompromised people it is essential . Increasing antimicrobial resistance in salmonella, in future, would limit the therapeutic options . During 2002, 198 persons were hospitalized for acute gastroenteritis . The 55% of cases were female, the age ranged between 4 and 94 years and the 25% of them were > 60 years old . The 58.5% of hospitalizations occurred between June and October . Non-typhi salmonella was isolated in the stool of 49 persons, with a rate of hospitalization of 24.7% respect to other causes of gastroenteritis . The incidence of resistance that was defined as resistance to one or more drugs was 14.3% . Only one non-typhi salmonella showed a multiple resistance (> four drugs) . Among all antibiotics tested, only the fluorquinolones showed a susceptibility in vitro in all strains . Non typhoidal Salmonellosis is a public healt problem in the world and it will be important to restrict the use of antibiotics in medicine and veterinary to reduce the spread of multiresistant strains.

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