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;amp;#197; in length . This trimeric rod displays an exceedingly high intrinsic thermostability (Tm ~85&amp;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