Antimicrob Agents Chemother, 2001 Oct, 45(10), 2716 - 22 Evidence for transfer of CMY-2 AmpC beta-lactamase plasmids between Escherichia coli and Salmonella isolates from food animals and humans; Winokur PL et al.; Escherichia coli is an important pathogen that shows increasing antimicrobial resistance in isolates from both animals and humans . Our laboratory recently described Salmonella isolates from food animals and humans that expressed an identical plasmid-mediated, AmpC-like beta-lactamase, CMY-2 . In the present study, 59 of 377 E . coli isolates from cattle and swine (15.6%) and 6 of 1,017 (0.6%) isolates of human E . coli from the same geographic region were resistant to both cephamycins and extended-spectrum cephalosporins . An ampC gene could be amplified with CMY-2 primers in 94.8% of animal and 33% of human isolates . Molecular epidemiological studies of chromosomal DNA revealed little clonal relatedness among the animal and human E . coli isolates harboring the CMY-2 gene . The ampC genes from 10 animal and human E . coli isolates were sequenced, and all carried an identical CMY-2 gene . Additionally, all were able to transfer a plasmid containing the CMY-2 gene to a laboratory strain of E . coli . CMY-2 plasmids demonstrated two different plasmid patterns that each showed strong similarities to previously described Salmonella CMY-2 plasmids . Additionally, Southern blot analyses using a CMY-2 probe demonstrated conserved fragments among many of the CMY-2 plasmids identified in Salmonella and E . coli isolates from food animals and humans . These data demonstrate that common plasmids have been transferred between animal-associated Salmonella and E . coli, and identical CMY-2 genes carried by similar plasmids have been identified in humans, suggesting that the CMY-2 plasmid has undergone transfer between different bacterial species and may have been transmitted between food animals and humans. Vet Microbiol, 2001 Nov 8, 83(2), 177 - 83 Chromosomal integration and expression of the Escherichia coli K88 gene cluster in Salmonella enterica ser . Choleraesuis strain 54 (SC54); Lee E et al.; Attempts to develop live vaccines to protect against enterotoxigenic Escherichia coli (ETEC) infection by induction of both cell-mediated and mucosal immunity, and serum antibody responses have included use of recombinant Salmonella strains that produce K88 fimbrial antigens (Hone et al., 1988; Attridge et al., 1988; Morona et al., 1994) . However, none of the recombinant Salmonella vectors has been licensed by the United States Department of Agriculture (USDA) for use as a live vaccine in pigs in the United States . A variant of Salmonella enterica ser . Choleraesuis strain 54 (SC54) is currently used as a safe and effective intranasal attenuated live vaccine in pigs . In order to expand the efficacy of this live vaccine strain, we sought to modify strain SC54 to express the K88 antigens of ETEC . To accomplish this, a plasmid-based system was used to integrate the K88 gene cluster into the chromosome of strain SC54 by site-specific recombination . The K88 antigens were expressed by strain SC54, and the gene cluster was stably maintained in the host. FEMS Microbiol Lett, 2001 Sep 11, 203(1), 63 - 8 The Escherichia coli orthologue of the Salmonella ushB gene (ushB(c)) produces neither UDP-sugar hydrolase activity nor detectable protein, but has an identical sequence to that of Escherichia coli cdh; Schroder W et al.; Salmonella ushB, which encodes a membrane-bound UDP-sugar hydrolase, has an Escherichia coli orthologue (ushB(c)) which does not detectably produce this activity . In this report, we show that ushB(c) does not produce any detectable protein either, despite being transcribed normally . Remarkably, ushB(c) is shown to have 100% sequence identity with E . coli cdh, previously characterised as encoding an active CDP-diglyceride hydrolase, an apparent contradiction with implications regarding enzyme evolution . We suggest that a useful gene designation is cdh (ushB(c)) rather than either ushB(c) or cdh, alone. J Appl Microbiol, 2001 Sep, 91(3), 442 - 52 A rat model for dose-response relationships of Salmonella Enteritidis infection; Havelaar AH et al.; AIMS: To develop an animal model to study dose-response relationships of enteropathogenic bacteria . METHODS AND RESULTS: Adult, male Wistar Unilever rats were exposed orally to different doses of Salmonella enterica serovar Enteritidis after overnight starvation and neutralization of gastric acid by sodium bicarbonate . The spleen was the most sensitive and reproducible organ for detection of dose-dependent systemic infection . Illness was only observed in animals exposed to doses of 10(8) cfu or more . At lower doses, histopathological changes in the gastro-intestinal tract were observed, but these were not accompanied by illness . Marked changes in numbers and types of white blood cells, as well as delayed-type hyperresponsiveness, indicated a strong, dose-dependent cellular immune response to Salm . Enteritidis . CONCLUSION: The rat model is a sensitive and reproducible tool for studying the effects of oral exposure to Salm . Enteritidis over a wide dose range . SIGNIFICANCE AND IMPACT OF THE STUDY: The rat model allows controlled quantification of different factors related to the host, pathogen and food matrix on initial stages of infection by food-borne bacterial pathogens. Przegl Epidemiol, 2001, 55(1-2), 93 - 102 {Foodborne infections and poisonings in Poland in 1999}; Przybylska A; The total number of 27,103 cases of bacterial foodborne infections and intoxications were registered in 1999 . The incidence was 70.1/100,000 . 6,269 cases were registered in 336 outbreaks of collective illnesses (4 people and more) . S . Enteritidis was found in 97.1% of cases in outbreaks caused by Salmonella spp . The main vehicle of foodborne infections and intoxications in outbreaks was food prepared from eggs (52.5% cases in outbreaks) . Private homes prevailed (58.3% of outbreaks) among the places of the ready made food production . Five epidemics with more than 100 cases each were registered in 1999. Mol Microbiol, 2001 Sep, 41(5), 1211 - 22 Identification of Salmonella typhi genes expressed within macrophages by selective capture of transcribed sequences (SCOTS); Daigle F et al.; Salmonella enterica serovar Typhi (S . typhi) is a human-restricted pathogen which causes typhoid fever . Relatively little is known about S . typhi host interaction as animal models of this disease are severely limited by the lack of virulence of S . typhi in other hosts . The virulence of other Salmonella serovars in animal models is dependent on the abilities of these bacteria to survive within host macrophages . We have used selective capture of transcribed sequences (SCOTS) to identify S . typhi genes expressed during growth in human macrophages . This positive cDNA selection technique identified 28 distinct clones representing previously identified as well as novel, uncharacterized and hypothetical gene sequences that are expressed intracellularly . Transcripts for the Vi capsular antigen and genes whose products are involved in stress responses and nutrient acquisition were obtained from intracellular bacteria using SCOTS . Most of these clones are present in the S . typhimurium genome and are also expressed in murine macrophages . Nineteen of these gene sequences were disrupted insertionally in S . typhi, and most of the resulting mutants exhibited a lower level of survival within macrophages compared with the wild-type parent strain . Mutant strains, transformed with a copy of a wild-type gene, exhibited a macrophage survival level similar to that of the parental strain. J Mol Biol, 2001 Sep 14, 312(2), 359 - 69 The role in flagellar rod assembly of the N-terminal domain of Salmonella FlgJ, a flagellum-specific muramidase; Hirano T et al.; The C-terminal half of the Salmonella flagellar protein FlgJ has peptidoglycan hydrolyzing activity and it has been suggested that it is a flagellum-specific muramidase which locally digests the peptidoglycan layer to permit assembly of the rod structure to proceed through the periplasmic space . It was also suggested that FlgJ might be involved in rod formation itself, although there was no direct evidence for this . We purified basal body structures from SJW1437(flgJ) transformed with plasmids encoding various mutant FlgJ proteins and found that these basal bodies possessed the periplasmic P ring but lacked the outer membrane L ring; they also lacked a hook at their distal end . All of these mutant FlgJ proteins had an altered or missing C-terminal domain but had at least the first 151 amino acid residues of the N-terminal domain . Immunoblotting analysis of fractionated cell extracts revealed that a rod/hook export class protein, FlgD, was exported to the periplasm but not to the culture supernatant in these mutants . FlgJ was shown to physically interact with several proteins, and especially FliE and FlgB, which are believed to reside at the cell-proximal end of the rod . On the basis of these results, we conclude that the N-terminal 151 amino acid residues of FlgJ are directly involved in rod formation and that the muramidase activity of FlgJ, though needed for formation of the L ring and subsequent events such as hook formation, is not essential for rod or P ring formation . In contrast, muramidase activity alone does not support rod assembly . Infect Immun, 2001 Oct, 69(10), 6523 - 6 New Zealand white rabbit as a nonsurgical experimental model for Salmonella enterica gastroenteritis; Hanes DE et al.; Rabbits orally challenged with Salmonella enterica developed a dose-dependent diarrheal disease comparable to human salmonellosis . Viable Salmonella organisms recovered from the intestine and deep tissues indicate local and systemic infections . Therefore, results show that the rabbit can be used as a model for diarrheal disease and sequelae associated with salmonellosis. Infect Immun, 2001 Oct, 69(10), 6463 - 74 Salmonella enterica serovar Typhimurium response involved in attenuation of pathogen intracellular proliferation; Cano DA et al.; Salmonella enterica serovar Typhimurium proliferates within cultured epithelial and macrophage cells . Intracellular bacterial proliferation is, however, restricted within normal fibroblast cells . To characterize this phenomenon in detail, we investigated the possibility that the pathogen itself might contribute to attenuating the intracellular growth rate . S . enterica serovar Typhimurium mutants were selected in normal rat kidney fibroblasts displaying an increased intracellular proliferation rate . These mutants harbored loss-of-function mutations in the virulence-related regulatory genes phoQ, rpoS, slyA, and spvR . Lack of a functional PhoP-PhoQ system caused the most dramatic change in the intracellular growth rate . phoP- and phoQ-null mutants exhibited an intracellular growth rate 20- to 30-fold higher than that of the wild-type strain . This result showed that the PhoP-PhoQ system exerts a master regulatory function for preventing bacterial overgrowth within fibroblasts . In addition, an overgrowing clone was isolated harboring a mutation in a previously unknown serovar Typhimurium open reading frame, named igaA for intracellular growth attenuator . Mutations in other serovar Typhimurium virulence genes, such as ompR, dam, crp, cya, mviA, spiR (ssrA), spiA, and rpoE, did not result in pathogen intracellular overgrowth . Nonetheless, lack of either SpiA or the alternate sigma factor RpoE led to a substantial decrease in intracellular bacterial viability . These results prove for the first time that specific serovar Typhimurium virulence regulators are involved in a response designed to attenuate the intracellular growth rate within a nonphagocytic host cell . This growth-attenuating response is accompanied by functions that ensure the viability of intracellular bacteria. Infect Immun, 2001 Oct, 69(10), 6391 - 400 Macrophage nitric oxide synthase associates with cortical actin but is not recruited to phagosomes; Webb JL et al.; Nitric oxide (NO) produced from inducible NO synthase (iNOS) is an important component of host defense against intracellular pathogens . To understand how phagocytes deliver NO to ingested microorganisms while avoiding cytotoxicity, we set out to study the subcellular localization of iNOS within macrophages following phagocytosis . Confocal microscopy of immunostained cells showed that iNOS was located not only diffusely within cytoplasm but also in vesicles, as well as immediately adjacent to the peripheral cell membrane . This peripheral iNOS colocalized with the cortical actin cytoskeleton and was removed by the actin-depolymerizing drug cytochalasin B . Biochemical fractionation of RAW 264 macrophages showed that 32.75% (+/-5.11%; n = 3) of iNOS was present in a particulate fraction, which cosedimented with low-density cellular vesicles . Following phagocytosis of latex beads, zymosan, immunoglobulin G-coated beads, or complement-coated zymosan, submembranous cortical iNOS was not recruited to phagosomes, nor was there any relocalization of intracellular iNOS . Similarly, following phagocytosis of Salmonella enterica serovar Typhimurium there was no recruitment of iNOS to the Salmonella vacuole at any stage after internalization . NO mediated significant killing of intracellular S . enterica serovar Typhimurium in RAW macrophages treated with lipopolysaccharide and gamma interferon; this was evident 4 h after infection . Although not recruited to phagosomes, iNOS association with the submembranous cortical actin cytoskeleton is ideally suited to deliver NO to microbes in contact with the cell surface and may contribute to early killing of ingested Salmonella. Carbohydr Res, 2001 Sep 21, 335(1), 23 - 32 (Chemo)enzymatic synthesis of dTDP-activated 2,6-dideoxysugars as building blocks of polyketide antibiotics; Amann S et al.; The flexible substrate spectrum of the recombinant enzymes from the biosynthetic pathway of dTDP-beta-L-rhamnose in Salmonella enterica, serovar typhimurium (LT2), was exploited for the chemoenzymatic synthesis of deoxythymidine diphosphate- (dTDP-) activated 2,6-dideoxyhexoses . The enzymatic synthesis strategy yielded dTDP-2-deoxy-alpha-D-glucose and dTDP-2,6-dideoxy-4-keto-alpha-D-glucose (13) in a 40-60 mg scale . The nucleotide deoxysugar 13 was further used for the enzymatic synthesis of dTDP-2,6-dideoxy-beta-L-arabino-hexose (dTDP-beta-L-olivose) (15) in a 30-mg scale . The chemical reduction of 13 gave dTDP-2,6-dideoxy-alpha-D-arabino-hexose (dTDP-alpha-D-olivose) (1) as the main isomer after product isolation in a 10-mg scale . With 13 as an important key intermediate, the in vitro characterization of enzymes involved in the biosynthesis of dTDP-activated 2,6-dideoxy-, 2,3,6-trideoxy-D- and L-hexoses can now be addressed . Most importantly, compounds 1 and 15 are donor substrates for the in vitro characterization of glycosyltransferases involved in the biosynthesis of polyketides and other antibiotic/antitumor drugs . Their synthetic access may contribute to the evaluation of the glycosylation potential of bacterial glycosyltransferases to generate hybrid antibiotics. Environ Microbiol, 2001 Jul, 3(7), 421 - 30 The chicken, the egg and Salmonella enteritidis; Guard-Petter J; Salmonella enterica serovar Enteritidis is the cause of the food-borne salmonellosis pandemic in humans, in part because it has the unique ability to contaminate eggs without causing discernible illness in the birds infected . The infection route to humans involves colonization, survival and multiplication of the pathogen in the hen house environment, the bird and, finally, the egg . This review highlights the stages of transmission and discusses evidence that altered bacterial growth patterns and specific cell surface characteristics contribute to the adaptation of S . enteritidis to these diverse environments. Food Addit Contam, 2001 Sep, 18(9), 797 - 809 Anti-mutagenic compounds from corn; Burgos-Hernandez A et al.; In previous studies with aflatoxin-contaminated corn an uncharacteristic response for AFB1 in the Salmonella/microsomal mutagenicity assay (Ames test) was observed and the presence of anti-aflatoxin factors in the corn was suggested . In the current study, corn was extracted and fractionated using thin layer chromatography (TLC) using different developing solvent systems and the Ames test was used to monitor for anti-mutagenic activity in the corn fractions . Both Salmonella tester strains TA98 and TA100 with metabolic activation (S9) were used . Several corn fractions, at different stages in the isolation and purification process, showed anti-mutagenic dose-responses when exposed to pure AFB1 . Corti extracts were non-toxic to the tester strains and TLC fractions that showed the best anti-mutagenic dose-responses were selected for further partial characterization analyses. Mutat Res, 2001 Sep 20, 496(1-2), 5 - 13 Antimutagenic effects of the mushroom Agaricus blazei Murrill extracts on V79 cells; Menoli RC et al.; Agaricus blazei Murrill, a native mushroom in Brazil, has been widely consumed in different parts of the world due to its medicinal power . Its anticarcinogenic activity has been shown in experimental animals, and antimutagenic activity has been demonstrated only in Salmonella . In this work, the mutagenic and antimutagenic activities of mushroom teas of strains AB96/07, AB96/09 and AB97/11 were evaluated in Chinese hamster V79 cells, using the comet assay and the micronucleus test . The cells were treated with three different concentrations (0.05, 0.1 and 0.15) of teas prepared from a 2.5% aqueous solution, under three different temperatures: (1) room (20-25 degrees C); (2) ice-cold (2-8 degrees C); and (3) warm (60 degrees C) . The teas were applied in co-, pre- and post-treatments in combination with the mutagen methyl methanesulfonate (MMS; 1.6x10(-4) and 4x10(-4)M) . The duration of the treatment was 1h in the comet assay and 2h in the micronucleus test . The results showed that the mushroom was not mutagenic itself . Nevertheless, the mushroom is an efficient antimutagen against the induction of micronuclei by MMS in all concentrations and preparations tested . The observed reductions in the frequencies of micronuclei ranged from 61.5 (room temperature 0.1% tea in post-treatment) to 110.3% (co-treatment with warm and ice-cold 0.15% tea) . In the comet assay, the antimutagenic activity was detected only when the cells were pre-treated with the following teas: warm 0.1 and 0.15%, room temperature 0.05% and ice-cold 0.1% . The results indicate that the mushroom A . blazei extracts are antimutagenic when tested in V79 cells. FEMS Immunol Med Microbiol, 2001 Aug, 31(2), 93 - 6 Modulation of human humoral immune response through orally administered bovine colostrum; He F et al.; Eighteen healthy volunteers were randomized into two treatment groups and consumed liquid prepackaged bovine colostrum whey and placebo for 7 days . On days 1, 3 and 5, an attenuated Salmonella typhi Ty21a oral vaccine was given to all subjects to mimic an enteropathogenic infection . The circulating antibody secreting cells and the expression of phagocytosis receptors of the subjects before and after oral immunization were measured with the ELISPOT assay and flow cytometry . All subjects responded well to the vaccine . No significant differences were observed in ELISPOT values for IgA, IgG, IgM, Fcgamma and CR receptor expression on neutrophils and monocytes between the two groups . There was a trend towards greater increase in specific IgA among the subjects receiving their vaccine with bovine colostrum . These results suggest that bovine colostrum may possess some potential to enhance human special immune responses. Microbios, 2001, 106 Suppl 1, 31 - 9 Inhibition by the essential oils of peppermint and spearmint of the growth of pathogenic bacteria; Imai H et al.; The effects of the, essential oils of peppermint (Mentha piperita L.), spearmint Mentha spicata L.) and Japanese mint (Mentha, arvensis L.), of four major constituents of the esssential oil of peppermint, and of three major constituents of the essential oil of spearmint, on the proliferation of Helicobacter pylori, Salmonella enteritidis, Escherichia coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin sensitive Staphylococccus aureus (MSSA) were examined . The essential oils and the various constituents inhibited the proliferation of each strain in liquid culture in a dose-dependent manner . In addition, they exhibited bactericidal activity in phosphate-buffered saline . The antibacterial activities varied among the bacterial species tested but were almost the same against antibiotic-resistant and antibiotic-sensitive strains of Helicobacter pylori and S . aureus . Thus, the essential oils and their constituents may be useful as potential antibacterial agents for inhibition of the growth of pathogens. J Med Microbiol, 2001 Sep, 50(9), 780 - 6 Distribution and structural variation of the she pathogenicity island in enteric bacterial pathogens; Al-Hasani K et al.; Shigella flexneri serotype 2a carries a chromosomal pathogenicity island (PAI), termed the she PAI, that has been implicated in the pathogenesis of diarrhoeal disease . The complete nucleotide sequence and genetic organisation of the she PAI of S . flexneri 2a strain YSH6000T was determined recently . In the current study the distribution and structure of the she PAI was investigated by PCR and Southern analysis in 65 isolates of enteric pathogens including Shigella spp., enterohaemorrhagic Escherichia coli (EHEC), enteropathogenic E . coli (EPEC), enteroinvasive E . coli (EIEC), Yersinia enterocolitica and Salmonella enterica serovar Typhimurium . The study showed that the she PAI has undergone a variety of structural changes, defined by the presence or absence of specific marker genes in the PAI . The she PAI or structural variants of this element were found in all species of Shigella as well as in EIEC, EHEC and EPEC . No evidence of the PAI was found in Y . enterocolitica or Sal . Typhimurium . The structural form of the she PAI that exists in strain YSH6000T was present in all strains of S . flexneri serotype 2a and in some strains of S . flexneri serotypes 2b and 3c . Variants of the PAI that were missing one or more marker regions were found in all species of Shigella and in pathogenic strains of E . coli . In all strains, the PAIs have inserted into either pheV or a phe tRNA gene in another location on the chromosome . It was concluded that the she PAI is one of several closely related genetic elements that have disseminated throughout Shigella and pathogenic strains of E . coli and diverged into distinct stuctural forms. J Med Microbiol, 2001 Sep, 50(9), 770 - 9 Role of the mar locus in virulence of Salmonella enterica serovar Typhimurium DT104 in chickens; Randall LP et al.; The virulence of a Salmonella enterica serovar Typhimurium DT014 strain in which marA was insertionally inactivated was compared to its isogenic parent in vitro and in vivo . In vitro, the numbers of the marA mutant phagocytosed by porcine lung macrophages were significantly increased, while survival at 24 h inside macrophages and adherence to human gut cells were significantly reduced in comparison with the parent strain . In vivo, the marA inactivated strain, in competition with its parent strain, persisted for a shorter period in chickens, was present in the caeca at significantly lower levels and invaded the deeper organs to a significantly lesser extent . Therapeutic antibiotic treatment of one group of chickens with oxytetracycline favoured the persistence of both the parent strain and, to a lesser extent, the marA inactivated strain; but interestingly, increased tetracycline resistance of Salmonella isolates after treatment of birds with antibiotic was seen only for the parent strain . Further work is needed to elucidate how mar is involved in virulence and if its inactivation can minimise the ability of bacteria to become antibiotic-resistant in vivo. J Med Microbiol, 2001 Sep, 50(9), 759 - 69 An in-vitro model for studying the interaction of Escherichia coli O157:H7 and other enteropathogens with bovine primary cell cultures; Dibb-Fuller MP et al.; Sections of kidney, trachea, ileum, colon, rectum and rumen were removed at post mortem from a neonatal calf and, with the exception of the rumen, primary cell lines were established for each of the cell types . The adherence of enterohaemorrhagic Escherichia coli (EHEC) serotype O157:H7, enteropathogenic E . coli (EPEC) serotype O111, E . coli K12 (a laboratory adapted non-pathogenic strain) and Salmonella enterica serotype Typhimurium was assayed on each cell type . For all adherence assays on all cell lines, EHEC O157:H7 adhered to a significantly greater extent than the other bacteria . S . Typhimurium and EPEC O111 adhered to a similar extent to one another, whereas E . coli K12 was significantly less adherent by 100-fold . In all cell types, >10% of adherent S . Typhimurium bacteria invaded, whereas c . 0.01-0.1% of adherent EHEC O157:H7 and EPEC O111 bacteria invaded, although they are regarded as non-invasive . EHEC O157 generated actin re-arrangements in all cell types as demonstrated by fluorescent actin staining (FAS) under densely packed bacterial micro-colonies . EPEC O111 readily generated the localised adherent phenotype on bovine cells but generated only densely packed micro-colonies on HEp-2 cells . The intensity of actin re-arrangements induced in bovine cells by EPEC O111 was less than that induced by EHEC O157:H7 . The intimate attachment on all cell types by both EHEC O157:H7 and EPEC O111 was clearly demonstrated by scanning electron microscopy. Crit Care Med, 2001 Sep, 29(9), 1756 - 60 Hemodynamic effects of terlipressin (a synthetic analog of vasopressin) in healthy and endotoxemic sheep; Scharte M et al.; OBJECTIVE: Hypotension, vasodilation, and vasoplegia are characteristic signs of septic shock . The vasoconstrictive response to catecholamines typically is reduced . A decreased vasopressive effect of catecholamines can be observed in the late phase of hemorrhagic shock . Interestingly, an unaltered vasopressive response to vasopressin can be demonstrated in hemorrhagic shock . In this study, we investigated the vasoconstrictive response to an agonist of the vasopressin receptor, terlipressin, in healthy sheep as well as in ovine hyperdynamic endotoxemia . DESIGN: Prospective controlled trial . SETTING: University research laboratory . SUBJECTS: Six female adult sheep . INTERVENTIONS: Healthy sheep, instrumented for chronic study, received terlipressin (15 microg/kg) as a bolus; 30 mins later, norepinephrine was continuously given for 30 mins . Three hours later, a continuous infusion of endotoxin (Salmonella typhosa, 10 ng x kg(-1) x min(-1)) was started in the same sheep and given for the next 23 hrs . After 20 hrs of endotoxemia, terlipressin and norepinephrine were given as described previously . MEASUREMENTS AND MAIN RESULTS: Hemodynamic parameters were measured before and 30 mins after application of terlipressin and after 30 mins of continuous infusion of norepinephrine . Terlipressin significantly increased systemic vascular resistance index in healthy and endotoxemic sheep (p <.05) . The increase was higher in endotoxemic compared with healthy animals (p <.05) . Only during endotoxemia, terlipressin increased pulmonary vascular resistance index . This was accompanied by a significant decrease in cardiac index, whereas mean pulmonary arterial pressure did not change after application of terlipressin . Additional treatment with norepinephrine did not further increase systemic vascular resistance index or pulmonary vascular resistance index . CONCLUSIONS: Terlipressin reversed the hemodynamic changes in ovine endotoxemia . However, its pulmonary vasopressive effect might limit its therapeutic use in septic shock. Jpn J Infect Dis, 2001 Jun, 54(3), 111 - 3 Molecular analysis of Salmonella Enteritidis isolates resistance to ampicillin and streptomycin from three outbreaks of food poisoning in Shiga prefecture; Matsune W et al.; In 1998 and 1999, there were three outbreaks caused by Salmonella Enteritidis in Shiga Prefecture . One outbreak was suspected to be a diffuse outbreak, caused by frozen cream puffs that had been sold in chain stores throughout Shiga Prefecture between the beginning of September and the beginning of October, 1998 . The other outbreaks occurred in May and in August, 1999 . All isolates of the three outbreaks showed an identical lysis pattern against the typing phage, though this pattern did not conform to the current scheme, so-called RDNC . In addition all isolates were resistant to ampicillin and streptomycin . However, the patterns of pulsed-field gel electrophoresis strongly indicated that the three outbreaks were actually independent. J Bacteriol, 2001 Oct, 183(19), 5733 - 42 SdiA of Salmonella enterica is a LuxR homolog that detects mixed microbial communities; Michael B et al.; Proteins of the LuxR family detect the presence of N-acylhomoserine lactones (AHLs) and regulate transcription accordingly . When AHLs are synthesized by the same species that detects them, the system allows a bacterium to measure the population density of its own species, a phenomenon known as quorum sensing . The sdiA genes of Escherichia coli and Salmonella enterica serovar Typhimurium are predicted to encode LuxR homologs . However, these species do not appear to synthesize AHLs or any other molecule detected by SdiA . It has previously been demonstrated that overexpression of sdiA results in the activation of the ftsQAZ locus in E . coli and four other loci in Salmonella serovar Typhimurium . Here we report that transcriptional fusions to these five loci fall into two classes . The first class requires overexpression of sdiA for activation . The second class responds to sdiA expressed from its natural position in the chromosome if the appropriate AHLs are added to the culture . The only member of the second class is a series of Prck-luxCDABE fusions in Salmonella serovar Typhimurium . SdiA responds with highest sensitivity to AHLs that have a keto modification at the third carbon and an acyl chain length of 6 or 8 (half-maximal response between 1 and 5 nM) . Growth of Salmonella in proximity to species known to synthesize these AHLs results in sdiA-dependent activation of the Prck-luxCDABE fusions . SdiA appears to be the first AHL receptor discovered that detects signals emanating exclusively from other species. J Bacteriol, 2001 Oct, 183(19), 5725 - 32 Complete nucleotide sequence of a 43-kilobase genomic island associated with the multidrug resistance region of Salmonella enterica serovar Typhimurium DT104 and its identification in phage type DT120 and serovar Agona; Boyd D et al.; This study describes the characterization of the recently described Salmonella genomic island 1 (SGI1) (D . A . Boyd, G . A . Peters, L.-K . Ng, and M . R . Mulvey, FEMS Microbiol . Lett . 189:285-291, 2000), which harbors the genes associated with the ACSSuT phenotype in a Canadian isolate of Salmonella enterica serovar Typhimurium DT104 . A 43-kb region has been completely sequenced and found to contain 44 predicted open reading frames (ORFs) which comprised approximately 87% of the total sequence . Fifteen ORFs did not show any significant homology to known gene sequences . A number of ORFs show significant homology to plasmid-related genes, suggesting, at least in part, a plasmid origin for the SGI1, although some with homology to phage-related genes were identified . The SGI1 was identified in a number of multidrug-resistant DT120 and S . enterica serovar Agona strains with similar antibiotic-resistant phenotypes . The G+C content suggests a potential mosaic structure for the SGI1 . Emergence of the SGI1 in serovar Agona strains is discussed. J Bacteriol, 2001 Oct, 183(19), 5580 - 8 Expression of cspH, encoding the cold shock protein in Salmonella enterica serovar Typhimurium UK-1; Kim BH et al.; Both Salmonella enterica serovar Typhimurium and Escherichia coli contain the cspH gene encoding CspH, one of the cold shock proteins (CSPs) . In this study, we investigated the expression of cspH in S . enterica serovar Typhimurium and found that it was induced in response to a temperature downshift during exponential phase . The cspH promoter was activated at 37 degrees C, and its mRNA was more stable than the other csp mRNAs at 37 degrees C . Moreover, lacZ expression of the translational cspH-lacZ fusion was induced at that temperature . Interestingly, the cspH mRNA had a much shorter 5'-untranslated region than those in the other cold-shock-inducible genes, and the promoter sequence, which was only 55 bp, was sufficient for cspH expression . The 14-base downstream box located 12 bases downstream of the initiation codon of cspH mRNA was essential for its cold shock activation. J Bacteriol, 2001 Oct, 183(19), 5554 - 61 Extragenic suppressors of growth defects in msbB Salmonella; Murray SR et al.; Lipid A, a potent endotoxin which can cause septic shock, anchors lipopolysaccharide (LPS) into the outer leaflet of the outer membrane of gram-negative bacteria . MsbB acylates (KDO)(2)-(lauroyl)-lipid IV-A with myristate during lipid A biosynthesis . Reports of knockouts of the msbB gene describe effects on virulence but describe no evidence of growth defects in Escherichia coli K-12 or Salmonella . Our data confirm the general lack of growth defects in msbB E . coli K-12 . In contrast, msbB Salmonella enterica serovar Typhimurium exhibits marked sensitivity to galactose-MacConkey and 6 mM EGTA media . At 37 degrees C in Luria-Bertani (LB) broth, msbB Salmonella cells elongate, form bulges, and grow slowly . msbB Salmonella grow well on LB-no salt (LB-0) agar; however, under specific shaking conditions in LB-0 broth, many msbB Salmonella cells lyse during exponential growth and a fraction of the cells form filaments . msbB Salmonella grow with a near-wild-type growth rate in MSB (LB-0 containing Mg(2+) and Ca(2+)) broth (23 to 42 degrees C) . Extragenic compensatory mutations, which partially suppress the growth defects, spontaneously occur at high frequency, and mutants can be isolated on media selective for faster growing derivatives . One of the suppressor mutations maps at 19.8 centisomes and is a recessive IS10 insertional mutation in somA, a gene of unknown function which corresponds to ybjX in E . coli . In addition, random Tn10 mutagenesis carried out in an unsuppressed msbB strain produced a set of Tn10 inserts, not in msbB or somA, that correlate with different suppressor phenotypes . Thus, insertional mutations, in somA and other genes, can suppress the msbB phenotype. Toxicology, 2001 Sep 25, 166(3), 161 - 70 Partial chemical/structural elucidation of anti-mutagenic compounds from corn; Burgos-Hernandez A et al.; In this study, corn fractions obtained from an isolation process of anti-mutagenic factors in our previous research work (Burgos-Hernandez et al., 2001), were subjected to several analyses for chemical/structural elucidation . The anti-mutagenic activity of these fractions was tested against aflatoxin B(1) (AFB(1)) and 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), a mutagen that does not require bioactivation . Two concentrations of this agent in the corn fractions were tested for anti-mutagenicity in the Salmonella/microsomal mutagenicity assay, using tester strain TA100 with no metabolic activation . Corn fractions tested showed evidence of anti-mutagenic activity by producing a dose-response type of relationship between a constant amount of MNNG and several concentrations of tested corn fraction . Five different varieties of yellow corn were tested in order to determine if the anti-mutagenic factors were intrinsic to corn . Variety of the corn did not show an effect on the reduction of the mutagenic potential of AFB(1) suggesting that anti-mutagenic compounds are intrinsic to corn . Four corn fractions, previously obtained after the isolation process were analyzed by MALDI-MS and GC-MS . MALDI-MS showed the presence of two groups of molecules or molecular fragments . The molecular mass of one group ranged from 250 to 370 m/z, the other ranged from 540 to 640 m/z . GC-MS identified linoleic acid as one of the compounds responsible for the anti-mutagenic activity present in corn. Adv Space Res, 1992, 12(2-3), 103 - 10 Mutagenic effects of heavy ions in bacteria; Krasavin EA et al.; The peculiarities and mechanisms of the mutagenic action of gamma-rays and heavy ions on bacterial cells have been investigated . Direct mutations in the lac-operon of E . coli in wild type cells and repair deficient strains have been detected . Furthermore, the induction of revertants in Salmonella tester strains was measured . It was found that the mutation rate was a linear-quadratic function of dose in the case of both gamma-rays and heavy ions with LET up to 200 keV/micrometer . The relative biological effectiveness (RBE) increased with LET up to 20 keV/micrometer . Low mutation rates were observed in repair deficient mutants with a block of SOS-induction . The induction of SOS-repair by ionizing radiation has been investigated by means of the "SOS-chromotest" and lambda-prophage induction . It was shown that the intensity of the SOS-induction in E . coli increased with increasing LET up to 40-60 keV/micrometer. Chemosphere, 2001 Sep, 44(8), 1723 - 36 Urban airborne particulate: genotoxicity evaluation of different size fractions by mutagenesis tests on microorganisms and comet assay; Buschini A et al.; The genotoxic effects of different size fractions of airborne particulate (Total, PM10 and PM25), extracted with acetone or toluene, were evaluated by: the Ames plate test (TA98 and TA100 strains, w/o S9), gene conversion and reversion (w/o endogenous metabolic activation) in the Saccharomyces cerevisiae D7 strain, and the comet assay on human leukocytes . The data on human leukocytes confirm the sensitivity of the comet assay and its applicability to assess genotoxicity in environmental samples . The PM2.5 fraction of airborne particulate generally shows the highest concentration of DNA-damaging compounds . Genotoxic response, in all the test systems applied, is highly dependent on extraction solvent used . Acetone seems to extract compounds with more similar genotoxic responses in the three test systems used than toluene extracts . Toluene appears to extract air pollutants genotoxic on yeast and leukocytes but is mainly cytotoxic on Salmonella. Nahrung, 2001 Aug, 45(4), 293 - 7 Acceleration of curing period of pastrami manufactured from buffalo meat: Chemical and microbiological properties; Ibrahim HM; Usually the curing period of meat used for pastrami manufacture is three weeks at room temperature . In the present work a trial aimed to accelerate the curing period of pastrami (dry cured meat) prepared from buffalo lean round muscles by heat treatment (approximately 71 degrees C--internal; for partial drying) was carried out to investigate the probable changes during processing and in quality parameters of the end product . Results showed that pH value and the residual NaNO2 content decreased, while lactic acid and conversion in meat pigment percentages were increased . The determined data indicated remarkable decrease of moisture content during aging and curing periods, while the NaCl content in the investigated product was noticeably increased . During pastrami processing soluble proteins were decreased; the sarcoplasmic protein fraction denatured more rapidly than myofibrillar protein . On the other hand, the non-protein nitrogen and the insoluble protein nitrogen were increased gradually during ageing and after the heat treatment step . Slight variations in their values were observed during ripening of pastrami (complete curing and drying in air at room temperature up to 6 days) . Heat treatment caused apparent decrease in Aerobic Plate Count (APC) . Salmonella and Coliform bacteria were not detected through meat curing and in the end product . The suggested heat-treated pastrami was of good quality and nearly similar to the traditional sample. J Infect, 2001 Feb, 42(2), 161 - 2 Unusual presentation of typhoid fever: cutaneous vasculitis, pancreatitis, and splenic abscess; Lambotte O et al.; We report a case of typhoid fever with an unusual presentation: prolonged fever with cutaneous vasculitis, pancreatitis, and splenic abscess . This is the first case of cutaneous leukocytoclastic vasculitis associated with Salmonella typhi . The diagnosis was made upon isolation of S . typhi in blood cultures, and after ruling out other causes of leukocytoclastic vasculitis . The outcome was favourable with antibiotics alone without surgery . J Infect, 2001 Feb, 42(2), 145 - 53 Molecular epidemiological analysis of Salmonella enterica serotype Derby infections in Hong Kong; Ling JM et al.; OBJECTIVES: We aimed to study the antimicrobial susceptibilities and molecular epidemiology of Salmonella enterica serotype Derby, a unique and common salmonella serotype in Hong Kong . METHODS: Salmonella Derby strains isolated from stools of patients in a large general hospital in Hong Kong from 1989 to 1994 and from food samples isolated in the Public Health Laboratory were randomly selected and investigated for the antimicrobial susceptibilities by determining the minimal inhibitory concentrations of 19 antimicrobial agents and their relatedness using plasmid analysis, ribotyping, pulsed-field gel electrophoresis (PFGE) and total DNA fingerprinting . RESULTS: About 50% of the 127 isolates studied were susceptible to all the 19 antibiotics tested, although resistance to tetracycline (49%) and sulfamethoxazole (38%) was high . Only 12% did not harbour any detectable plasmids, while the rest contained plasmids in 51 profiles . There were two predominant clones, one comprising of 35% of isolates that could not be pulsotyped because discrete bands were not discernible after PFGE and another comprising 34% of isolates that could be pulsotyped . The remaining 31% belonged to a variety of types . CONCLUSIONS: Approximately 70% of S . Derby belonging to two clones were endemic in the community, while the remaining isolates belonged to a variety of types which were probably a result of sporadic infection . The sources of human infections were foods, since most isolates from foods also belonged to the two endemic clones . Typing of S . Derby isolates from other sources such as animals or the environment would help elucidate how foods were contaminated . PFGE might not be universally applicable to all salmonella strains. Clin Infect Dis, 2001 Oct 1, 33(7), 1010 - 4 Epub 2001 Aug 22. Reactive arthritis and Reiter's syndrome following an outbreak of gastroenteritis caused by Salmonella enteritidis; Dworkin MS et al.; Reactive arthritis and Reiter's syndrome have been reported following gastroenteritis . Prevalence studies for these conditions are uncommon, and the prevalence of Reiter's syndrome after Salmonella enteritidis infection has not been previously reported . After a large outbreak of S . enteritidis gastroenteritis, a survey of persons exposed to the implicated food source was conducted, and those with reactive arthritis were evaluated for possible risk factors . Among 481 persons responding to the questionnaire, 217 cases of S . enteritidis gastroenteritis were identified (31 confirmed and 186 clinical cases; attack rate, 45%) . Twenty-nine percent of the cases had symptoms of reactive arthritis, 3% had symptoms of Reiter's syndrome, and 10% had reactive arthritis with oral ulcers . Markers for severe illness (diarrhea > or =7 days, emergency room visit or hospitalization, and antibiotic treatment) were statistically significant but colinear factors associated with reactive arthritis . Increased awareness of postdysenteric reactive arthritis and Reiter's syndrome is recommended. Appl Environ Microbiol, 2001 Sep, 67(9), 4128 - 36 Effect of challenge temperature and solute type on heat tolerance of Salmonella serovars at low water activity; Mattick KL et al.; Salmonella spp . are reported to have an increased heat tolerance at low water activity (a(w); measured by relative vapor pressure {rvp}), achieved either by drying or by incorporating solutes . Much of the published data, however, cover only a narrow treatment range and have been analyzed by assuming first-order death kinetics . In this study, the death of Salmonella enterica serovar Typhimurium DT104 when exposed to 54 combinations of temperature (55 to 80 degrees C) and a(w) (rvp 0.65 to 0.90, reduced using glucose-fructose) was investigated . The Weibull model (LogS = -bt(n)) was used to describe microbial inactivation, and surface response models were developed to predict death rates for serovar Typhimurium at all points within the design surface . The models were evaluated with data generated by using six different Salmonella strains in place of serovar Typhimurium DT104 strain 30, two different solutes in place of glucose-fructose to reduce a(w), or six low-a(w) foods artificially contaminated with Salmonella in place of the sugar broths . The data demonstrate that, at temperatures of > or =70 degrees C, Salmonella cells at low a(w) were more heat tolerant than those at a higher a(w) but below 65 degrees C the reverse was true . The same patterns were generated when sucrose (rvp 0.80 compared with 0.90) or NaCl (0.75 compared with 0.90) was used to reduce a(w), but the extent of the protection afforded varied with solute type . The predictions of thermal death rates in the low-a(w) foods were usually fail-safe, but the few exceptions highlight the importance of validating models with specific foods that may have additional factors affecting survival. Mutat Res, 2001 Oct 18, 497(1-2), 153 - 7 Mutagenicity of the malondialdehyde oligomerization products 2-(3'-oxo-1'-propenyl)-malondialdehyde and 2,4-dihydroxymethylene-3-(2,2-dimethoxyethyl)glutaraldehyde in Salmonella; Riggins JN et al.; Malondialdehyde (MDA), a byproduct of non-enzymatic lipid peroxidation and prostaglandin biosynthesis, has been shown to be a weak frameshift mutagen in Salmonella mutagenicity assays . Because it is a dialdehyde, MDA can undergo self condensation to form polymeric products . It is possible that these condensation products are highly mutagenic and have contributed to previously reported estimates of MDA mutagenicity . We synthesized two major MDA polymerization products, (1) 2-(3'-oxo-1'-propenyl)-malondialdehyde {(MDA)2} and (2) 2,4-dihydroxymethylene-3-(2,2-dimethoxyethyl)glutaraldehyde {(MDA)3Me2} and tested their mutagenicity in the Salmonella frameshift tester strains hisD3052 and TA94 (hisD3052/pKM101) . Analysis of the reversion rates revealed both (MDA)2 and (MDA)3Me2 to be weak mutagens, approximately equipotent to MDA . Although both (MDA)2 and (MDA)3Me2 are mutagenic, the fact that their formation is thermodynamically unfavorable under physiological conditions suggests they do not contribute significantly to the mutagenicity of MDA solutions. Mol Genet Genomics, 2001 Aug, 265(6), 941 - 53 Site-directed mutagenesis and phylogenetic comparisons of the Escherichia coli Tus protein: DNA-protein interactions alone can not account for Tus activity; Henderson TA et al.; The Tus protein of Escherichia coli is capable of arresting DNA replication in an orientation-dependent manner when bound to specific sequences in the bacterial chromosome called Ter sites . Arrest of DNA replication has been postulated to occur either by a barrier mechanism, where Tus acts as a physical block to replication fork progression, or through protein-protein interactions between Tus and some component of the replication fork . A previous mutational analysis of Tus suggested that the amino acids in the L1 loop might play a role in replication arrest . Site-directed mutagenesis of amino acids in the L1 loop and other amino acid residues on the "non-permissive" face of Tus was performed to identify residues that affected Tus function . One mutant, E47Q, gave results that are inconsistent with the barrier model, showing a greater affinity for the Ter site (with a t 1/2 of 348 min versus 150 min for wild-type Tus) but a reduced ability to arrest DNA replication in vivo . In addition to the site-directed mutagenesis studies, the tus genes of Salmonella, Klebsiella, and Yersinia were sequenced and the proteins expressed in E . coli to assess their ability to arrest DNA replication . The results presented here support a role for protein-protein interactions in Tus function, and suggest that residues E47 and E49 participate in replication fork arrest. J Trop Pediatr, 2001 Aug, 47(4), 250 - 1 Peripheral gangrene complicating Salmonella typhi septicaemia in a Gambian infant; Okoko BJ et al.; A 1-year-old malnourished boy, who presented with Salmonella typhi septicaemia with a 4-day history of febrile illness, dehydration and severe anaemia, developed bilateral dry gangrene of the hands and feet . Although he improved appreciably, he suffered auto-amputation of the distal phalanges of the left foot after 3 weeks of illness . A high index of suspicion and prompt treatment is highly critical in the treatment of septicaemia in young children. J Trop Pediatr, 2001 Aug, 47(4), 211 - 4 Serum C-reactive protein concentrations in Malaysian children with enteric fever; Choo KE et al.; To investigate the role of serum C-reactive protein (CRP) in the diagnosis of typhoid fever, we studied 227 febrile Malaysian children hospitalized during a 12-month period . The children were: culture-positive for Salmonella typhi (Group 1; n = 108); culture-negative but with typical clinical features of typhoid fever (Group 2; n = 60); or had non-typhoidal illness (Group 3; n = 59) . Group 1 children had the highest serum CRP concentrations (geometric mean {SD range}; 43 {12-150} mg/l vs . 26 {8-85} mg/l in Group 2 and 21 {4-110} mg/l in Group 3; p < 0.001) . In regression analysis, age, patient group and fever duration were independently associated with serum CRP (p < 0.05) but gender was not . In Group 1 patients, there was a significant positive association between serum CRP and Widal O and H agglutinin titres . In receiver-operator characteristic (ROC) analysis of serum CRP for Groups 1 and 2 combined, compared with Group 3, the area under the curve (AUC) was 0.65 . These data show that the serum CRP is highest in culture-positive children with enteric fever and reflects the immune response to the infection in this group . Nevertheless, serum CRP had relatively low sensitivity and specificity for confirmed or clinically diagnosed typhoid fever (68 and 58 per cent, respectively at 'cut-off' concentration 30.0 mg/l), and an AUC value only moderately above that associated with no predictive power (0.5) . Although of limited use as a primary diagnostic test, a raised serum CRP may still have a place as one of a range of features that facilitate assessment of a febrile child in a typhoid-endemic area. Eur J Epidemiol, 2001, 17(1), 31 - 40 Salmonella serotype Virchow causing salmonellosis in a Spanish region . Characterization and survey of clones by DNA fingerprinting, phage typing and antimicrobial resistance; Martin MC et al.; The diversity of Salmonella serotype Virchow organisms causing human salmonellosis in a Spanish region over 1990-1996 was studied by genetic and phenotypic procedures . Isolates showing identical DNA fingerprintings (ribotypes, RAPD-, REP- and ERIC-types) were clustered into the same lineage . Eight lineages were defined, of which only one caused diseases throughout the studied period . Eleven phage types (PTs) were represented, the most frequent being PTs 8, 19, 31, throughout the study period, and PT4a only during 1994 . Class I integrons with variable regions of 1000-, 1600-, and 2300-bp in size were respectively present in 24, 3 and 5 multiresistant isolates; 43.5% of isolates were susceptible to antimicrobials, the rest were grouped into 17 R-profiles, including from one up to eight resistances . Plasmids could be recovered from 71.5% of isolates and grouped into 25 plasmid profiles (with 1-7 plasmids each); a 3.6 kb cryptic-plasmid and a 60 kb virulence-plasmid were those most frequently found . Phage type, presence and size of integrons, and resistance profile were used to differentiate 39 clones . During the period studied 135 cases of Virchow salmonellosis were identified; 93 were apparently sporadic whereas the remainder were associated with four outbreaks . Infants under 1 year constituted the most frequent age group, with 30 gastroenteritis and two septicaemia episodes . In the four outbreaks, different clones falling into the prevalent lineage were implicated but each clone was involved in only one outbreak. J Mol Evol, 2001 Sep, 53(3), 244 - 50 Limitations of compositional approach to identifying horizontally transferred genes; Wang B; Genes with atypical G+C content and pattern of codon usage in a certain genome are possibly of exotic origin, and this idea has been applied to identify horizontal events . In this way, it was postulated that a total of 755 genes in the E . coli genome are relics of horizontal events after the divergence of E . coli from the Salmonella lineage 100 million years ago (Lawrence and Ochman, 1998) . In this paper we propose a new way to study sequence composition more thoroughly . We found that although the 755 genes differ in composition from other genes in the E . coli genome, the difference is minor . If we accepted that these genes are horizontally transferred, then (1) it would be more likely that they were transferred from genomes evolutionarily closely related to E . coli; but (2) the dating method used by Lawrence and Ochman (1997, 1998) largely underestimated the average age of introduced sequences in the E . coli genome, in particular, most of the 755 genes should be introduced into E . coli before, instead of after, the divergence of E . coli from the Salmonella lineage . Our study reveals that atypical G+C content and pattern of codon usage are not reliable indicators of horizontal gene transfer events. Gastroenterology, 2001 Sep, 121(3), 580 - 91 Probiotic bacteria enhance murine and human intestinal epithelial barrier function; Madsen K et al.; BACKGROUND & AIMS: The probiotic compound, VSL#3, is efficacious as maintenance therapy in pouchitis and ulcerative colitis . The aim of this study was to determine the efficacy of VSL#3 as a primary therapy in the treatment of colitis in the interleukin (IL)-10 gene-deficient mouse . Mechanisms of action of VSL#3 were investigated in T(84) monolayers . METHODS: IL-10 gene-deficient and control mice received 2.8 x 10(8) colony-forming units per day of VSL#3 for 4 weeks . Colons were removed and analyzed for cytokine production, epithelial barrier function, and inflammation . VSL#3 or conditioned media was applied directly to T(84) monolayers . RESULTS: Treatment of IL-10 gene-deficient mice with VSL#3 resulted in normalization of colonic physiologic function and barrier integrity in conjunction with a reduction in mucosal secretion of tumor necrosis factor alpha and interferon gamma and an improvement in histologic disease . In vitro studies showed that epithelial barrier function and resistance to Salmonella invasion could be enhanced by exposure to a proteinaceous soluble factor secreted by the bacteria found in the VSL#3 compound . CONCLUSIONS: Oral administration of VSL#3 was effective as primary therapy in IL-10 gene-deficient mice, and had a direct effect on epithelial barrier function. Gastroenterology, 2001 Sep, 121(3), 554 - 60 Clinical studies in persistent diarrhea: dietary management with green banana or pectin in Bangladeshi children; Rabbani GH et al.; BACKGROUND & AIMS: Because of the beneficial intestinal effects of dietary fibers, we have evaluated the therapeutic effects of green banana or pectin in children with persistent diarrhea . METHODS: In a double-blind trial, 62 boys, age 5-12 months, were randomly given a rice-based diet containing either 250 g/L of cooked green banana (n = 22) or 4 g/kg pectin (n = 19) or the rice-diet alone (control, n = 21), providing 54 kcal/dL daily for 7 days . Stool weight and consistency, frequency of vomiting and purging, and duration of illness were measured . RESULTS: Most children (60%) had no pathogens isolated from stools, 17% had rotavirus, 5% Vibrio cholerae, 4% Salmonella group B, and 11% had enterotoxigenic Escherichia coli infections . By day 3 posttreatment, significantly (P < 0.001) more children recovered from diarrhea receiving pectin or banana than controls (59%, 55%, and 15%, respectively) . By day 4, these proportions correspondingly increased to 82%, 78%, and 23%, respectively, the study diet groups being significantly (P < 0.001) different than controls . Green banana and pectin significantly (P < 0.05) reduced amounts of stool, oral rehydration solution, intravenous fluid, and numbers of vomiting, and diarrheal duration . CONCLUSIONS: Green banana and pectin are useful in the dietary management of persistent diarrhea in hospitalized children and may also be useful to treat children at home. J Endotoxin Res, 2001, 7(1), 73 - 8 Regulated covalent modifications of lipid A; Raetz CR; Regulated covalent modifications of lipid A are implicated in virulence of pathogenic Gram-negative bacteria . The Salmonella PhoP/PhoQ-activated gene pagP is required for resistance to cationic antimicrobial peptides and for biosynthesis of hepta-acylated lipid A species containing palmitate . Interestingly, pagP encodes an unusual enzyme of lipid A biosynthesis localized in the outer membrane, whereas all previously characterized lipid A enzymes are cytoplasmic or associated with the inner membrane . PagP is not unique, however, as pagL encodes another outer membrane enzyme in Salmonella that deacylates the 3 position of lipid A.S . typhimurium also synthesizes S-2-hydroxymyristate modified lipid A in a PhoP/PhoQ-dependent manner . We postulated that 2-hydroxylation might be catalyzed by a novel dioxygenase . Using well-characterized dioxygenase sequences as probes, tBLASTn searches revealed unassigned open reading frame(s) with similarity to mammalian aspartyl beta-hydroxylases in bacteria known to make 2-hydroxyacylated lipid A . The S . typhimurium aspartyl beta-hydroxylase homologue (lpxO) was cloned and expressed in Escherichia coli K-12, which does not contain lpxO . Analysis of the resulting construct revealed that lpxO expression induces O(2)-dependent formation of 2-hydroxymyristate-modified lipid A in E . coli . LpxO may be an inner membrane enzyme that catalyzes Fe(2+)/ascorbate/alpha-ketoglutarate dependent hydroxylation of lipid A . We propose that 2-hydroxymyristate released from LPS inside infected animal cells might be converted to 2-hydroxymyristoyl coenzyme A, a potent inhibitor of protein N-myristoyl transferase. Vet Res Commun, 2001 Aug, 25(6), 437 - 47 Immunopotentiation of a developed Salmonella enterica serotype enteritidis vaccine by thymulin and zinc in meat chicken breeders; Barbour EK et al.; The humoral immunity, spleen and thymus weight indices, lymphocyte count in the thymus cortex, and granuloma diameter at vaccination sites were assessed in four differently immunopotentiated groups of meat chicken breeders . Breeders in the first two groups were given a killed Salmonella enterica serotype Enteritidis (SE) vaccine subcutaneously at 15 and 19 weeks of age . Breeders in the third and fourth groups were left unvaccinated . Breeders in the first group were further immunopotentiated with zinc and thymulin . Each bird in the first group was given the immunopotentiators intraperitoneally in a volume of 0.1 ml at intervals of 3 days for a period of 3 weeks, starting at 15 weeks of age . At each time, each bird in the first group received thymulin (10 ng) and ZnCl2 (1 micromol/L), using a carboxymethyl cellulose carrier, totalling 90 ng thymulin and 9 micromol of ZnCl2 per bird . Each bird in the first three groups was challenged orally with 6.7 x 10(6) cfu/ml of highly virulent SE organisms, at an age of 22 weeks . The first group, which had received zinc and thymulin, had the earliest and highest humoral immune response to SE (p<0.05) . This was observed at 2 and 4 weeks after the first vaccination . In addition, the first group had the highest mean thymus weight index, and the highest mean lymphocyte count in the thymus cortex . No significant difference was observed between the first two vaccinated groups in the mean granuloma diameter developed at the two vaccination sites 48 h after administration of the vaccine (p>0.05). Toxicology, 2001 Sep 14, 166(1-2), 71 - 8 Toxicological profile of pollutants in surface water from an area in Taihu Lake, Yangtze Delta; Shen JH et al.; The environment in urbanized areas is often contaminated with a complex mixture of toxic compounds originating from industries, agriculture and private households . Most of the contaminants end up in surface waters, such as lakes, rivers and finally the sea . Toxic contaminants may disturb the biological condition of aquatic ecosystems and be harmful for humans, if they are transported to human food or drinking water . A variety of biological tests have been introduced for monitoring the toxicological profile of aquatic ecosystems . In the present investigation, genotoxic, hormone disrupting and Ah-receptor activity was analyzed in water collected in January 1999 at Meiliang Bay, Taihu Lake, China, near to the city of Wuxi in the Shanghai area . Significant mutagenic activity could be detected in water extracts with the Salmonella/microsome assay and the arabinose resistance test . Frame shift mutations were the predominant mode of action . Ah-receptor active compounds were detected by using a luciferase reporter gene assay (CALUX-assay) . The estimated toxic equivalent factor-values ranged between 134 and 232 pg TCCD-equivalents per liter lake water . The estrogen-like potential of Taihu water was estimated with two luciferase reporter gene assays using transgenic human cell lines expressing estrogen receptor alpha . Estradiol equivalents obtained with water extracts were in the range of 2.2-12.1 ng/l . We also analyzed the concentrations of 17-beta-estradiol and ethinylestradiol in the extracts using a high-pressure liquid chromatography-method . The values obtained correlated with the biologically determined estradiol equivalents, indicating that the estrogenic activity is mainly due to natural and synthetic hormones rather than xenoestrogens. J Mol Biol, 2001 Aug 24, 311(4), 735 - 49 Structure and characterization of AgfB from Salmonella enteritidis thin aggregative fimbriae; White AP et al.; The agfBAC operon of Salmonella enteritidis encodes thin aggregative fimbriae, fibrous, polymeric structures primarily composed of AgfA fimbrins . Although uncharacterized, AgfB shows a 51 % overall amino acid sequence similarity to AgfA . Using AgfB epitope-specific antiserum, AgfB was detected as a minor component of whole, purified fimbriae . Like AgfA, AgfB was released from purified fimbriae by >70 % formic acid, whereupon both AgfA-AgfA and AgfA-AgfB dimers as well as monomers were detected . This suggested that AgfB may form specific, highly stable, structural associations with AgfA in native fimbrial filaments, associations that were weakened in structurally unstable fibers derived from AgfA chimeric fimbrial mutants . Detailed sequence comparisons between AgfA and AgfB showed that AgfB harbored a similar fivefold repeated sequence pattern (x(6)QxGx(2)NxAx(3)Q), and contained structural motifs similar to the parallel beta helix model proposed for AgfA . Molecular modeling of AgfB revealed a 3D structure remarkably similar to that of AgfA, the structures differing principally in the surface disposition of non-conserved, basic, acidic and non-polar residues . Thus AgfB is a fimbrin-like structural homologue of AgfA and an integral, minor component of native thin aggregative fimbrial fibers . AgfB from an agfA deletion strain was detected as a non-fimbrial, SDS-insoluble form in the supernatant and was purified . AgfA from an agfB deletion strain was found in both SDS-soluble and insoluble, non-fimbrial forms . No AgfA-AgfA dimers were detected in the absence of AgfB . Fimbriae formation by intercellular complementation between agfB and agfA deletion strains could not be shown under a variety of conditions, indicating that AgfA and AgfB are not freely diffusible in S . enteritidis . This has important implications on the current assembly hypothesis for thin aggregative fimbriae . Acta Microbiol Pol, 2001, 50(1), 27 - 35 Heat resistance and growth of Salmonella enteritidis, Listeria monocytogenes and Aeromonas hydrophila in whole liquid egg; Abdel Karem H et al.; Salmonella enteritidis ATCC,13067, Listeria monocytogenes ATCC,19116 and Aeromonas hydrophila ATCC,7965 strains were evaluated for growth and thermal resistance in liquid whole egg (LWE) . Each strain grew well in LWE at temperatures between 4 and 30 degrees C, except S . enteritidis which grew weakly at 4 and 10 degrees C . Maximum populations for each strain increased with increasing growth temperature . The thermal destruction of each strain was determined in six liquid products . The egg products used were LWE, LWE with 5, 10 and 15% NaCl and LWE with 5 and 10% sucrose . L . monocytogenes tended to be more heat resistant than S . enteritidis and A . hydrophila . The highest kill rates were noted in LWE, while survival was best in those products supplemented with NaCl . Radiation D10 values of strains in LWE were 0.18, 0.39 and 0.49 kGy for A . hydrophila, S . enteritidis and L . monocytogenes, respectively. Bioseparation, 2000, 9(6), 379 - 84 PCR identification of Salmonella cells in food and stool samples after immunomagnetic separation; Spanova A et al.; The purpose of the present study was to investigate the application of various sample preparation methods (cell washing before lysis, purification of DNA using phenol extraction method, immunomagnetic separation-IMS) for the final PCR identification of Salmonella cells . The presence of PCR inhibitors in processed food products (milk powder and dried eggs) can be the cause of false-negative results in PCR without IMS of target cells . It was also demonstrated that IMS-PCR was successfully used for identification and quick confirmation of untypical Salmonella strains isolated from human stool samples and rabbit meat . However, IMS cannot eliminate intracellular PCR inhibitors present in immunoseparated Salmonella cells . These inhibitors must be taken into consideration in evaluation of PCR procedure. Mutat Res, 2001 Jun 27, 493(1-2), 127 - 37 Induction of -2 frameshift mutations by 2-nitrofluorene, N-hydroxyacetylaminofluorene, and N-2-acetylaminofluorene in reversion assays in Escherichia coli strains differing in permeability and acetyltransferase activity; Hoffmann GR et al.; The mutagenicity of 2-nitrofluorene (NF), N-hydroxyacetylaminofluorene (N-OH-AAF), and N-2-acetylaminofluorene (AAF) was measured in strains of Escherichia coli that contain a lacZ allele that reverts by -2 frameshift mutations from CG(5) to CG(4) . Mutagenesis was compared in a strain having wild-type permeability and metabolism, a strain with increased permeability caused by a lipopolysaccharide-defective (LPS(d)) mutation, a strain with N- and O-acetyltransferase (NAT/OAT) activity conferred by the Salmonella nat gene on plasmid pYG219, and a strain carrying both an LPS(d) mutation and pYG219 . The LPS(d) mutation facilitated the measurement of mutagenicity but was not absolutely required, in that lower levels of mutagenicity were detected in LPS(+) strains . The NAT/OAT activity conferred by pYG219 strongly potentiated the mutagenicity of NF and N-OH-AAF . Surprisingly, AAF was mutagenic in the NAT/OAT LPS(d) strain without an exogenous P450 metabolic activation system . Its activity may be ascribable to the detection of a directly mutagenic impurity by the highly sensitive strain or to a low level of metabolic activation by the bacteria under the assay conditions . The findings add to the evidence that the lacZ allele derived from E . coli strain CC109 is an effective indicator of -2 frameshift mutagenesis and that strains expressing high levels of NAT/OAT activity are highly sensitive in monitoring the mutagenicity of nitroarenes and aromatic amides. Indian Heart J, 2001 May-Jun, 53(3), 350 - 1 Infective endocarditis due to an unusual serotype of Salmonella; Ghadage DP et al.; Salmonellae are a rare cause of infective endocarditis . We report a case in which Salmonella enterica serotype Worthington was isolated from a case of endocarditis . The isolate was resistant to ampicillin, gentamicin, amikacin and chloramphenicol and sensitive to ciprofloxacin and cefotaxime. Braz J Biol, 2001 May, 61(2), 329 - 32 Genotoxic evaluation of the effect of Thuya occidentalys tinctures; Valsa JO et al.; Three tinctures samples from extracts of the popular medicinal plant Thuya occidentalis were tested in vitro through two short term tests for measuring the activity of genotoxic chemicals . Using the Salmonella/mammalian-microsome (Mutatest) assay and the SOS-chromotest (induction of beta-galactosidase in Escherichia coli), none of the extract was effective in inducing mutagenesis or beta-galactosidase synthesis (as an indicator of general and early sign of DNA damage), even with metabolization. Trends Microbiol, 2001 Aug, 9(8), 372 - 6 Can a 'flawless' live vector vaccine strain be engineered? Galen JE, Levine MM. The efficiency of any live bacterial vector vaccine hinges on its ability to present sufficient foreign antigen to the human immune system to initiate the desired protective immune response(s) . However, synthesis of sufficient levels of heterologous antigen can result in an increase in metabolic burden with an accompanying decrease in the fitness of the live vector, which can ultimately lower desired immune responses to both live vector and heterologous antigen . Here, we explore the underlying mechanisms of metabolic load and propose ways of minimizing such burdens to enhance the fitness and immunogenicity of Salmonella-based live vector vaccines. Mol Cell Probes, 2001 Aug, 15(4), 209 - 15 Multiplex PCR for the detection of tetracycline resistant genes; Ng LK et al.; Specific primer pairs were selected for the PCR amplification of 14 tetracycline resistant genes commonly found in Gram positive and Gram negative organisms . Combinations of primer pairs were used in multiplex PCR reactions to detect specific groups of tet genes as follows; Group I tet (B), tet (C), tet (D); Group II tet (A), tet (E), tet (G); Group III tet (K), tet (L), tet (M), tet (O), tet (S); Group IV tetA (P), tet (Q), tet (X) . To test the multiplex PCR, Groups I and II were used on 25 clinical isolates of Salmonella enterica serovar Typhimurium DT104 . Group III primers were used to investigate 19 clinical isolates of methicillin-resistant Staphylococcus aureus . Multiplex PCR should result in significant savings in terms of labour and cost in analysis of a large number of strains when compared with using an individual PCR for targeting each gene . It may also be a useful method to differentiate the types of tetracycline resistance when used as an additional marker for the purpose of outbreak investigation and surveillance . Vet Q, 2001 Jul, 23(3), 121 - 5 Administration of acidified drinking water to finishing pigs in order to prevent Salmonella infections; van der Wolf PJ et al.; The aim of the study was to test whether acidified drinking water, with two millilitres of an acid mixture per litre, was able to reduce the number of Salmonella infections in finishing pig herds . In each compartment, half of the pens were supplied with acidified water and the other pens served as negative control . In three herds the required dose was not applied to the pigs as a result of various practical problems . In another herd, all pigs remained seronegative throughout the study . Analysis of the remaining three herds showed a large and significant treatment effect in one herd (P<0.001) . As a result of the small number of observations and the overall lower seroprevalence in the control groups, the other two herds only showed a statistical trend to a treatment effect (0.10<P<0.05) . The main practical problem was the clogging of drinking nipples as a result of fungal growth in the pipelines. J Food Prot, 2001 Aug, 64(8), 1240 - 3 Two processing methods for the isolation of Salmonella from naturally contaminated alfalfa seeds; Inami GB et al.; Two processing methods were examined for the recovery of Salmonella from naturally contaminated alfalfa seed . Seed samples, from each of three investigations, were processed by sprouting and shredding before preenrichment and culture . In lot A, Salmonella serotype Newport was isolated from 3 of 30 sample units with the sprouting method and 2 of 30 with the shredding method . In lot B, three serotypes in various combinations were isolated from 10 of 30 sample units with the sprouting method and 9 of 30 with the shredding method . In lot C, Salmonella group C1 was isolated from 27 of 30 sample units with the sprouting method and 24 of 30 with the shredding method . Additionally, serotype Newport was found in one lot C sample unit . Using shredded seed data, a most probable number (MPN) for Salmonella contamination per lot was calculated . Serotype Newport was estimated at 0.07 MPN/100 g in lot A; the concentration for three serotypes was estimated to be 0.36 MPN/100 g in lot B; Salmonella group C1 was estimated at 1.8 MPN/100 g in lot C . Our success in isolating Salmonella from alfalfa seeds was likely attributed to the volume of material tested and the quick acquisition of the seeds after the outbreak was identified . Shredding the seeds was easier and yielded definitive results more quickly than sprouting. J Food Prot, 2001 Aug, 64(8), 1194 - 8 Home-style beef jerky: effect of four preparation methods on consumer acceptability and pathogen inactivation; Harrison JA et al.; The safety of homemade jerky continues to be questioned . Producing a safe product that retains acceptable quality attributes is important . Lethality of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes as well as consumer acceptability and sensory attributes of jerky prepared by four methods were examined . Preparation methods were drying marinated strips at 60 degrees C (representing a traditional method), boiling strips in marinade or heating in an oven to 71 degrees C prior to drying, and heating strips in an oven after drying to 71 degrees C . A 60-member consumer panel rated overall acceptability . A 10-member descriptive panel evaluated quality attributes . Samples heated after drying and samples boiled in marinade prior to drying had slightly higher acceptability scores but were not statistically different from traditional samples . Although the four treatments were significantly different in color (P = 0.0001), saltiness (P = 0.0001), and texture (P = 0.0324), only texture appeared to influence overall consumer acceptability . Microbial challenge studies subjecting the pathogens to the four treatments showed a 5.8-, 3.9-, and 4.6-log reduction of E . coli O157:H7, L . monocytogenes, and Salmonella, respectively, even with traditional drying . Oven treatment of strips after drying was shown to have the potential to reduce pathogen populations further by approximately 2 logs . In conclusion, a safer, yet acceptable home-dried beef jerky product can be produced by oven-heating jerky strips after drying. J Food Prot, 2001 Aug, 64(8), 1188 - 93 Pathogen testing of ready-to-eat meat and poultry products collected at federally inspected establishments in the United States, 1990 to 1999; Levine P et al.; The Food Safety and Inspection Service (FSIS) conducted microbiological testing programs for ready-to-eat (RTE) meat and poultry products produced at approximately 1,800 federally inspected establishments . All samples were collected at production facilities and not at retail . We report results here for the years 1990 through 1999 . Prevalence data for Salmonella, Listeria monocytogenes, Escherichia coli O157:H7, or staphylococcal enterotoxins in nine different categories of RTE meat and poultry products are presented and discussed . The prevalence data have certain limitations that restrict statistical inferences, because these RTE product-testing programs are strictly regulatory in nature and not statistically designed . The cumulative 10-year Salmonella prevalences were as follows: jerky, 0.31%; cooked, uncured poultry products, 0.10%; large-diameter cooked sausages, 0.07%; small-diameter cooked sausages, 0.20%; cooked beef, roast beef, and cooked corned beef, 0.22%; salads, spreads, and pates, 0.05%; and sliced ham and luncheon meat, 0.22% . The cumulative 3-year Salmonella prevalence for dry and semidry fermented sausages was 1.43% . The cumulative 10-year L . monocytogenes prevalences were as follows: jerky, 0.52%; cooked, uncured poultry products, 2.12%; large-diameter cooked sausages, 1.31%; small-diameter cooked sausages, 3.56%; cooked beef, roast beef, and cooked corned beef, 3.09%; salads, spreads, and pates, 3.03%; and sliced ham and luncheon meat, 5.16% . The cumulative 3-year L . monocytogenes prevalence for dry and semidry fermented sausages was 3.25% . None of the RTE products tested for E . coli O157:H7 or staphylococcal enterotoxins was positive . Although FSIS and the industry have made progress in reducing pathogens in these products, additional efforts are ongoing to continually improve the safety of all RTE meat and poultry products manufactured in federally inspected establishments in the United States. J Food Prot, 2001 Aug, 64(8), 1134 - 7 Laying season and egg shell cracks on the growth of Salmonella enteritidis in the egg albumen during storage; Hara-Kudo Y et al.; We studied the effects of laying seasons and egg shell cracks on the ability of egg albumen to support the growth of Salmonella Enteritidis (SE) in eggs . Hens eggs used were those laid in February, June, and October in a farm in Japan and stored at 10, 20, and 30 degrees C, and at 30 degrees C after storage at 10 degrees C, immediately after receipt or after cracking the shell . At several-day intervals during storage, the egg contents were poured into a dish, SE was inoculated into albumen, and then the growth of SE during 3 days incubation at 18 degrees C was measured . The results demonstrated that storage temperature and laying season affected the growth of SE in the egg albumen . The proportion of eggs upon which albumen allowed the growth of SE was higher in the eggs stored at 30 degrees C than those stored at 10 degrees C . The growth of SE in eggs was lowest in the following order of laying: February, October, and June . SE grew preferably in albumen of cracked eggs than intact eggs. J Food Prot, 2001 Aug, 64(8), 1122 - 7 Effect of low-temperature, high-pressure treatment on the survival of Escherichia coli O157:H7 and Salmonella in unpasteurized fruit juices; Teo AY et al.; The destructive effect of high pressure (615 MPa) combined with low temperature (15 degrees C) on various strains of Escherichia coli O157:H7 and various serovars of Salmonella in grapefruit, orange, apple, and carrot juices was investigated . The three-strain cocktail of E . coli O157:H7 (SEA13B88, ATCC 43895, and 932) was found to be most sensitive in grapefruit juice (8.34-log reduction) and least in apple juice (0.41-log reductions) when pressurized at 615 MPa for 2 min at 15 degrees C . Correspondingly, no injured survivor was detected in grapefruit and carrot juices under similar treatment conditions . No Salmonella spp . were detected in a 2-min pressure treatment (615 MPa, 15 degrees C) of grapefruit and orange fruit juices . Except for Enteritidis, all four serovars tested in the present study have viability loss of between 3.92- and 5.07-log reductions when pressurized in apple juice at 615 MPa for 2 min at 15 degrees C . No injured cells were recovered from grapefruit and orange juices, whereas the same treatment demonstrated reduction in numbers of Salmonella serovars Agona and Muenchen in apple juices and to a lesser extent with Typhimurium, Agona, and Muenchen in carrot juice . The present study demonstrated that low-temperature, high-pressure treatment has the potential to inactivate E . coli O157:H7 strains and different Salmonella spp . in different fruit juices. J Food Prot, 2001 Aug, 64(8), 1116 - 21 Examination of bacteriophage as a biocontrol method for salmonella on fresh-cut fruit: a model study; Leverentz B et al.; The preparation and distribution of fresh-cut produce is a rapidly developing industry that provides the consumer with convenient and nutritious food . However, fresh-cut fruits and vegetables may represent an increased food safety concern because of the absence or damage of peel and rind, which normally help reduce colonization of uncut produce with pathogenic bacteria . In this study, we found that Salmonella Enteritidis populations can (i) survive on fresh-cut melons and apples stored at 5 degrees C, (ii) increase up to 2 log units on fresh-cut fruits stored at 10 degrees C, and (iii) increase up to 5 log units at 20 degrees C during a storage period of 168 h . In addition, we examined the effect of lytic, Salmonella-specific phages on reducing Salmonella numbers in experimentally contaminated fresh-cut melons and apples stored at various temperatures . We found that the phage mixture reduced Salmonella populations by approximately 3.5 logs on honeydew melon slices stored at 5 and 10 degrees C and by approximately 2.5 logs on slices stored at 20 degrees C, which is greater than the maximal amount achieved using chemical sanitizers . However, the phages did not significantly reduce Salmonella populations on the apple slices at any of the three temperatures . The titer of the phage preparation remained relatively stable on melon slices, whereas on apple slices the titer decreased to nondetectable levels in 48 h at all temperatures tested . Inactivation of phages, possibly by the acidic pH of apple slices (pH 4.2 versus pH 5.8 for melon slices), may have contributed to their inability to reduce Salmonella contamination in the apple slices . Higher phage concentrations and/or the use of low-pH-tolerant phage mutants may be required to increase the efficacy of the phage treatment in reducing Salmonella contamination of fresh-cut produce with a low pH. J Food Prot, 2001 Aug, 64(8), 1103 - 9 Development of a proposed standard method for assessing the efficacy of fresh produce sanitizers; Beuchat LR et al.; A series of studies was done for the purpose of developing a proposed standard method to evaluate point-of-use home sanitizers for fresh produce . Preliminary experiments were done to determine the survival of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes after inoculation onto the surface of ripe tomatoes and drying for up to 24 h at 22 +/- 2 degrees C . Within 2 h, the initial population (6.88 log10 CFU/tomato) of E . coli O157:H7 was reduced by approximately 3 log10, while reductions in similar initial populations of Salmonella and L . monocytogenes were approximately 1 and 0.6 log10 CFU/tomato, respectively, after 40 min and 3 h . A pilot study evaluated treatment with 200 ppm free chlorine and a prototype Fit produce wash (Fit) for their efficacy in killing a five-serotype mixture of Salmonella or L . monocytogenes spot inoculated on tomatoes using the proposed inoculation and recovery procedures . Inoculated tomatoes were sprayed with chlorinated water, Fit, or sterile distilled water (control) and hand rubbed for 30 s . Each tomato was then placed in a plastic bag and rinsed with 200 ml of sterile water by vigorously agitating for 30 s to simulate a procedure consumers might use for sanitizing and rinsing produce in a home setting . Each tomato was transferred to a second bag, and 20 ml of sterile 0.1% peptone was added; tomatoes were rubbed by hand for 40 s . Populations of Salmonella or L . monocytogenes in the rinse water and the 0.1% peptone wash solution were determined . Treatment with 200 ppm chlorine and Fit resulted in > or = 3.07 and > 6.83 log10 reductions, respectively, in Salmonella . Treatment with 200 ppm chlorine and Fit reduced the number of L . monocytogenes by > or = 3.33 and > or = 4.96 log10 CFU/tomato, respectively . The proposed standard method for testing the efficacy of point-of-use produce sanitizers needs to be evaluated for reproducibility of results through a larger scale series of experiments. Fed Regist, 2000 Dec 5, 65(234), 76092 - 114 Food labeling, safe handling statements, labeling of shell eggs; refrigeration of shell eggs held for retail distribution . Food and Drug Administration, HHS . Final rule; Salmonella dublin in Danish dairy herds: frequency of change to positive serological status in bulk tank milk ELISA in relation to serostatus of neighbouring farms; Cattle Health Laboratory, Danish Dairy Board, Brorup, Denmark . awe@svs.dk Bulk tank milk from 1,429 herds were collected in 3 rounds from 19 different geographic areas . The milk samples were tested by use of indirect LPS-ELISA procedure to detect Salmonella dublin antibodies . From the obtained OD-values herd seroprevalence in the given area was determined and GR-scores calculated for each herd by addition of the number of positive sampling rounds by the 5 geographically closest neighbour herds . In the 19 different areas the calculated prevalence ranged from 0.01 to 0.41 . Totally 3,697 GR-scores were given . The mean GR-scores in the areas ranged from 0.0 to 6.5 . Higher GR-scores were found in herds changing to seropositive status compared with herds seronegative throughout the study period . The results indicate that the risk for a dairy herd to receive S . dublin infection increases with the disease status among the nearest neighbours and with the prevalence of seropositive herds in the geographic area. Antimicrob Agents Chemother, 2001 Sep, 45(9), 2450 - 4 Mechanism of therapeutic effectiveness of cefixime against typhoid fever; Matsumoto Y et al.; beta-Lactams have been considered ineffective against organisms growing inside mammalian cells because of their poor penetration into cells . However, cefixime has been shown to be clinically effective against typhoid fever . The probable mechanism of therapeutic effectiveness of cefixime against typhoid fever was investigated using Salmonella enterica serovar Typhimurium instead of S . enterica serovar Typhi both in a cellular and in a mouse infection model . Cefixime was able to inhibit the growth of serovar Typhimurium inhabiting monocyte-derived THP-1 cells . Elongation of serovar Typhimurium in THP-1 cells was observed microscopically . Apparent morphological changes of serovar Typhimurium in THP-1 cells were also observed by electron microscopy . The concentration of cefixime inside THP-1 cells was almost half (46 to 48%) of the concentration outside the cells when serovar Typhimurium coexisted in the solution . The length of time after oral dosing (8 mg/kg) that cefixime was present-calculated from levels in serum-at a concentration above the MIC at which 90% of the serovar Typhi organisms inside human cells were inhibited was presumed to be more than 12 h . Cefixime also showed excellent activity in the mouse systemic and oral infection models based on infections caused by serovar Typhimurium . It is concluded that a fair amount of cefixime can enter mammalian cells and inhibit the growth of bacteria inside cells when the bacteria are sensitive enough to cefixime, as are serovars Typhimurium and Typhi. Sao Paulo Med J, 2001 Jul 5, 119(4), 150 - 3 Primary aortoenteric fistula related to septic aortitis; Tozzi FL et al.; CONTEXT: Primary aortoenteric fistulas usually result from erosion of the bowel wall due to an associated abdominal aortic aneurysm . A few patients have been described with other etiologies such as pseudoaneurysm originating from septic aortitis caused by Salmonella . OBJECTIVE: To present a rare clinical case of pseudoaneurysm caused by septic aortitis that evolved into an aortoenteric fistula . CASE REPORT: A 65-year-old woman was admitted with Salmonella bacteremia that evolved to septic aortitis . An aortic pseudoaneurysm secondary to the aortitis had eroded the transition between duodenum and jejunum, and an aortoenteric fistula was formed . In the operating room, the affected aorta and intestinal area were excised and an intestine-to-intestine anastomosis was performed . The aorta was sutured and an axillofemoral bypass was carried out . In the intensive care unit, the patient had a cardiac arrest that evolved to death. Mem Inst Oswaldo Cruz, 2001 Jul, 96(5), 621 - 5 Enteropathogens associated with diarrheal disease in infants of poor urban areas of Porto Velho, Rondônia: a preliminary study; Orlandi PP et al.; One hundred and thirty cases of diarrhea and 43 age-matched controls, 0 to 5 years old, were studied in a pediatric outpatient unit from a poor peri urban area of Porto Velho, Rondonia . Eighty percent of diarrheal cases were observed in the groups under 2 years of age . Rotavirus (19.2%) was the most frequent enteropathogen associated with diarrhea, followed by Shigella flexneri (6.15%) and S . sonnei (1.5%) and Salmonella sp . (6.9%) . Four cases of E . coli enterotoxigenic infections (3.1%), E . coli enteropathogenic (EPEC)(2.3%) one case of E . coli enteroinvasive infection (0.8%) and one case of Yersinia enterocolitica (0.8%) were also identified . Mixed infections were frequent, associating rotavirus, EPEC and Salmonella sp . with Entamoeba histolytica and Giardia lamblia. J Biol Chem, 2001 Oct 12, 276(41), 38044 - 51 Epub 2001 Aug 10. MD-2 binds to bacterial lipopolysaccharide; Viriyakosol S et al.; The exact roles and abilities of the individual components of the lipopolysaccharide (LPS) receptor complex of proteins remain unclear . MD-2 is a molecule found in association with toll-like receptor 4 . We produced recombinant human MD-2 to explore its LPS binding ability and role in the LPS receptor complex . MD-2 binds to highly purified rough LPS derived from Salmonella minnesota and Escherichia coli in five different assays; one assay yielded an apparent KD of 65 nm . MD-2 binding to LPS did not require LPS-binding proteins LBP and CD14; in fact LBP competed with MD-2 for LPS . MD-2 enhanced the biological activity of LPS in toll-like receptor 4-transfected Chinese hamster ovary cells but inhibited LPS activation of U373 astrocytoma cells and of monocytes in human whole blood . These data indicate that MD-2 is a genuine LPS-binding protein and strongly suggest that MD-2 could play a role in regulation of cellular activation by LPS depending on its local availability. Infect Immun, 2001 Sep, 69(9), 5911 - 3 Brucella abortus HtrA functions as an authentic stress response protease but is not required for wild-type virulence in BALB/c mice; Phillips RW et al.; A second mutation has recently been identified in the previously described Brucella abortus htrA mutant PHE1 . As a result of this finding, a new B . abortus htrA mutant, designated RWP11, was constructed to evaluate the biological function of the Brucella HtrA protease . RWP11 is more sensitive to oxidative killing in vitro and less resistant to killing by cultured murine neutrophils and macrophages than the virulent parental strain 2308 but is not attenuated in BALB/c mice through 4 weeks postinfection . The in vitro phenotype of B . abortus RWP11 is consistent with the proposed function of bacterial HtrA proteases as components of a secondary line of defense against oxidative damage . The in vivo phenotype of this mutant, however, indicates that, unlike the corresponding Salmonella and Yersinia proteins, Brucella HtrA does not play a critical role in virulence in the mouse model. Infect Immun, 2001 Sep, 69(9), 5726 - 35 In vivo activation of dendritic cells and T cells during Salmonella enterica serovar Typhimurium infection; Yrlid U et al.; The present study was initiated to gain insight into the interaction between splenic dendritic cells (DC) and Salmonella enterica serovar Typhimurium in vivo . Splenic phagocytic cell populations associated with green fluorescent protein (GFP)-expressing bacteria and the bacterium-specific T-cell response were evaluated in mice given S . enterica serovar Typhimurium expressing GFP and ovalbumin . Flow cytometry analysis revealed that GFP-positive splenic DC (CD11c+ major histocompatibility complex class II-positive {MHC-II+} cells) were present following bacterial administration, and confocal microscopy showed that GFP-expressing bacteria were contained within CD11c+ MHC-II+ splenocytes . Furthermore, splenic DC and T cells were activated following Salmonella infection . This was shown by increased surface expression of CD86 and CD40 on CD11c+ MHC-II+ cells and increased CD44 and CD69 expression on CD4+ and CD8+ T cells . Salmonella-specific gamma interferon (IFN-gamma)-producing cells in both of these T-cell subsets, as well as cytolytic effector cells, were also generated in mice given live bacteria . The frequency of Salmonella-specific CD4+ T cells producing IFN-gamma was greater than that of specific CD8+ T cells producing IFN-gamma in the same infected animal . This supports the argument that the predominant source of IFN-gamma production by cells of the specific immune response is CD4+ T cells . Finally, DC that phagocytosed live or heat-killed Salmonella in vitro primed bacterium-specific IFN-gamma-producing CD4+ and CD8+ T cells as well as cytolytic effector cells following administration into naive mice . Together these data suggest that DC are involved in priming naive T cells to Salmonella in vivo. Infect Immun, 2001 Sep, 69(9), 5619 - 25 Absence of all components of the flagellar export and synthesis machinery differentially alters virulence of Salmonella enterica serovar Typhimurium in models of typhoid fever, survival in macrophages, tissue culture invasiveness, and calf enterocolitis; Schmitt CK et al.; In this study, we constructed an flhD (the master flagellar regulator gene) mutant of Salmonella enterica serovar Typhimurium and compared the virulence of the strain to that of the wild-type strain in a series of assays that included the mouse model of typhoid fever, the mouse macrophage survival assay, an intestinal epithelial cell adherence and invasion assay, and the calf model of enterocolitis . We found that the flhD mutant was more virulent than its parent in the mouse and displayed slightly faster net growth between 4 and 24 h of infection in mouse macrophages . Conversely, the flhD mutant exhibited diminished invasiveness for human and mouse intestinal epithelial cells, as well as a reduced capacity to induce fluid secretion and evoke a polymorphonuclear leukocyte response in the calf ligated-loop assay . These findings, taken with the results from virulence assessment assays done on an fljB fliC mutant of serovar Typhimurium that does not produce flagellin but does synthesize the flagellar secretory apparatus, indicate that neither the presence of flagella (as previously reported) nor the synthesis of the flagellar export machinery are necessary for pathogenicity of the organism in the mouse . Conversely, the presence of flagella is required for the full invasive potential of the bacterium in tissue culture and for the influx of polymorphonuclear leukocytes in the calf intestine, while the flagellar secretory components are also necessary for the induction of maximum fluid secretion in that enterocolitis model . A corollary to this conclusion is that, as has previously been surmised but not demonstrated in a comparative investigation of the same mutant strains, the mouse systemic infection and macrophage assays measure aspects of virulence different from those of the tissue culture invasion assay, and the latter is more predictive of findings in the calf enterocolitis model. Infect Immun, 2001 Sep, 69(9), 5471 - 6 Salmonella enterica serovar Gallinarum requires the Salmonella pathogenicity island 2 type III secretion system but not the Salmonella pathogenicity island 1 type III secretion system for virulence in chickens; Jones MA et al.; Salmonella enterica serovar Gallinarum is a host-specific serotype that causes the severe systemic disease fowl typhoid in domestic poultry and a narrow range of other avian species but rarely causes disease in mammalian hosts . Specificity of the disease is primarily at the level of the reticuloendothelial system, but few virulence factors have been described other than the requirement for an 85-kb virulence plasmid . In this work, by making functional mutations in the type III secretion systems (TTSS) encoded by Salmonella pathogenicity island 1 (SPI-1) and SPI-2, we investigated the role of these pathogenicity islands in interactions between Salmonella serovar Gallinarum and avian cells in vitro and the role of these pathogenicity islands in virulence in chickens . The SPI-1 mutant showed decreased invasiveness into avian cells in vitro but was unaffected in its ability to persist within chicken macrophages . In contrast the SPI-2 mutant was fully invasive in nonphagocytic cells but failed to persist in macrophages . In chicken infections the SPI-2 mutant was attenuated while the SPI-1 mutant showed full virulence . In oral infections the SPI-2 mutant was not observed in the spleen or liver, and following intravenous inoculation it was cleared rapidly from these sites . SPI-2 function is required by Salmonella serovar Gallinarum for virulence, primarily through promoting survival within macrophages allowing multiplication within the reticuloendothelial system, but this does not preclude the involvement of SPI-2 in uptake from the gut to the spleen and liver . SPI-1 appears to have little effect on virulence and survival of Salmonella serovar Gallinarum in the host. Curr Opin Immunol, 2001 Aug, 13(4), 417 - 28 Immune responses to intracellular bacteria; Raupach B et al.; The multifaceted dialogue between intracellular bacteria and the mammalian host continues to be an exciting issue from both the scientific and public-health viewpoint . The recent year has witnessed some particularly impressive progress in knowledge about the two major culprits affecting the health of mankind, Mycobacterium tuberculosis and Salmonella typhi - the causative agents of tuberculosis and typhoid fever. Microbiol Immunol, 2001, 45(6), 425 - 32 Protective effect of OK-432 on mice against endotoxemia and infection with Pseudomonas aeruginosa and Salmonella enteritidis; Hashimoto M et al.; OK-432 has been used clinically as a biological response modifier for cancer therapy . We investigated here the protective effects of OK-432 against endotoxic shock and infectious death caused by Pseudomonas aeruginosa and Salmonella enteritidis in mice and proposed a possible mechanism . Pretreatment of OK-432 reduced the lethality of lipopolysaccharide (LPS)-induced endotoxic shock in D-(+)-galactosamine-sensitized C3H/HeN mice . OK-432 did not affect the TNFalpha production in blood, but it did decrease the susceptibility to TNFalpha . Furthermore, an acceleration of LPS clearance from blood was detected . The pretreatment of OK-432 also decreased the lethality of mice in bacterial infection caused by P . aeruginosa and S . enteritidis . The rapid decrease of the viable bacteria from the circulating blood and in spleen and liver in mice was observed in a manner similar to LPS clearance . These findings indicate that the protective effect of OK-432 against the endotoxemia and bacteremia may depend on an up-regulation of clearance of LPS and bacteria and the augmented resistance to TNFalpha. Microbiology, 2001 Aug, 147(Pt 8), 2203 - 14 The methylcitric acid pathway in Ralstonia eutropha: new genes identified involved in propionate metabolism; Bramer CO et al.; From Ralstonia eutropha HF39 null-allele mutants were created by Tn5 mutagenesis and by homologous recombination which were impaired in growth on propionic acid and levulinic acid . From the molecular, physiological and enzymic analysis of these mutants it was concluded that in this bacterium propionic acid is metabolized via the methylcitric acid pathway . The genes encoding enzymes of this pathway are organized in a cluster in the order prpR, prpB, prpC, acnM, ORF5 and prpD, with prpR transcribed divergently from the other genes . (i) prpC encodes a 2-methylcitric acid synthase (42720 Da) as shown by the measurement of the respective enzyme activity, complementation of a prpC mutant of Salmonella enterica serovar Typhimurium and high sequence similarity . (ii) For the translational product of acnM the function of a 2-methyl-cis-aconitic acid hydratase (94726 Da) is proposed . This protein and also the ORF5 translational product are essential for growth on propionic acid, as revealed by the propionic-acid-negative phenotype of Tn5-insertion mutants, and are required for the conversion of 2-methylcitric acid into 2-methylisocitric acid as shown by the accumulation of the latter, which could be purified as its calcium salt from the supernatants of these mutants . In contrast, inactivation of prpD did not block the ability of the cell to use propionic acid as carbon and energy source, as shown by the propionic acid phenotype of a null-allele mutant . It is therefore unlikely that prpD from R . eutropha encodes a 2-methyl-cis-aconitic acid dehydratase as proposed recently for the homologous prpD gene from S . enterica . (iii) The translational product of prpB encodes 2-methylisocitric acid lyase (32314 Da) as revealed by measurement of the respective enzyme activity and by demonstrating accumulation of methylisocitric acid in the supernatant of a prpB null-allele mutant . (iv) The expression of prpC and probably also of the other enzymes is regulated and is induced during cultivation on propionic acid or levulinic acid . The putative translational product of prpR (70895 Da) exhibited high similarities to PrpR of Escherichia coli and S . enterica, and might represent a transcriptional activator of the sigma-54 family involved in the regulation of the other prp genes . Since the prp locus of R . eutropha was very different from those of E . coli and S . enterica, an extensive comparison of prp loci available from databases and literature was done, revealing two different classes of prp loci. J Med Chem, 2001 Aug 16, 44(17), 2793 - 804 Toward the design of chemical libraries for mass screening biased against mutagenic compounds; Llorens O et al.; The ability to develop a chemical into a drug depends on multiple factors . Beyond potency and selectivity, ADME/PK and the toxicological profile of the compound play a significant role in its evaluation as a candidate for development . Those factors are being brought into bear earlier in the discovery process and even into the design of libraries for screening . The purpose of our study is the comparative analysis of simple physical characteristics of compounds that have been reported to be mutagens and nonmutagenic ones . The analysis of differences can lead to the development of knowledge-based biases in the libraries designed for massive screening . For each of four Salmonella strains, TA-98, TA-100, TA-1535, and TA-1537, an analysis of the statistical significance of the deviance of the averages for a number of global properties was carried out . The properties studied included parameters, such as topological indices, and bit strings representing the presence or absence of certain chemical moieties . The results suggest that mutagens display a larger number of hydrogen bond acceptor centers for most strains . Moreover, the use of bit strings points to the importance of certain molecular fragments, such a nitro groups, for the outcome of a mutagenicity study . Development of multivariate models based on global molecular properties or bit strings point to a small advantage of the latter for the prediction of mutagenicity . The benefits of the bit strings are in accord with the use of fragment-based approaches for the prediction of carcinogenicity and mutagenicity in methods described in the literature. Poult Sci, 2001 Aug, 80(8), 1105 - 8 Genetic line differences in survival and pathogen load in young layer chicks after Salmonella enterica serovar enteritidis exposure; Kaiser MG et al.; Early infection may result in long-term colonization of layers with Salmonella enterica sv . enteritidis (S . enteritidis, SE), resulting in shedding into table or hatching eggs . To evaluate genetic factors underlying early response to SE, genetic line differences in mortality and pathogen load at two sites (cecal lumen and spleen) were investigated . At day of hatch, chicks of four genetic lines were intra-esophageally inoculated with one of three doses of SE phage type 13a . There was a significant effect (P < 0.001) of genetic line on chick 6-d survival . The effect of genetic line was significant (P < 0.05) on survivors' SE burden in cecal content but not on SE burden per gram of spleen . The SE pathogen load of the spleen and the cecal content were not significantly correlated, indicating that independent host mechanisms are partly responsible for these two traits . Genetic line differences in chick survival and SE colonization of cecal content were demonstrated in young layer chicks. J Immunol, 2001 Aug 15, 167(4), 1882 - 5 Cutting edge: bacterial flagellin activates basolaterally expressed TLR5 to induce epithelial proinflammatory gene expression; Gewirtz AT et al.; Flagellin, the structural component of bacterial flagella, is secreted by pathogenic and commensal bacteria . Flagellin activates proinflammatory gene expression in intestinal epithelia . However, only flagellin that contacts basolateral epithelial surfaces is proinflammatory; apical flagellin has no effect . Pathogenic Salmonella, but not commensal Escherichia coli, translocate flagellin across epithelia, thus activating epithelial proinflammatory gene expression . Investigating how epithelia detect flagellin revealed that cell surface expression of Toll-like receptor 5 (TLR5) conferred NF-kappaB gene expression in response to flagellin . The response depended on both extracellular leucine-rich repeats and intracellular Toll/IL-1R homology region of TLR5 as well as the adaptor protein MyD88 . Furthermore, immunolocalization and cell surface-selective biotinylation revealed that TLR5 is expressed exclusively on the basolateral surface of intestinal epithelia, thus providing a molecular basis for the polarity of this innate immune response . Thus, detection of flagellin by basolateral TLR5 mediates epithelial-driven inflammatory responses to Salmonella. Microbes Infect, 2001 Jul, 3(9), 771 - 6 Inducible nitric oxide synthase and Salmonella infection; Cherayil BJ et al.; Salmonella infection is associated with the increased expression of inducible nitric oxide synthase in macrophages and other cells . This review summarizes current knowledge of the molecular mechanisms involved in the induction process, and discusses the functional significance of nitric oxide production in the context of host defense against Salmonella. Mol Microbiol, 2001 Jul, 41(2), 349 - 63 MlrA, a novel regulator of curli (AgF) and extracellular matrix synthesis by Escherichia coli and Salmonella enterica serovar Typhimurium; Brown PK et al.; Production of curli (AgF) adhesins by Escherichia coli and Salmonella enterica serovar Typhimurium (S . typhimurium) is associated with extracellular matrix production and is optimal at low temperature during stationary phase . Curli and extracellular matrix synthesis involves a complex regulatory network that is dependent on the CsgD (AgfD) regulator . We have identified a novel regulator, termed MlrA, that is required for curli production and extracellular matrix formation . Two cosmids from a genomic library of avian pathogenic E . coli chi7122 conferred mannose-resistant haemagglutination (HA) and curli production to E . coli HB101, which is unable to produce curli owing to a defective regulatory pathway . The rpoS gene, encoding a known positive regulator of curli synthesis, and the E . coli open reading frame (ORF) of unknown function, yehV, identified on each of these cosmids, respectively, conferred curli production and HA to E . coli HB101 . We have designated yehV as the mlrA gene for MerR-like regulator A because its product shares similarities with regulatory proteins of the MerR family . HA and curli production by strain chi7122 were abolished by disruption of rpoS, mlrA or csgA, the curli subunit gene . Both csgD and csgBA transcription, required for expression of curli, were inactive in an mlrA mutant grown under conditions that promote curli production . An mlrA homologue was identified in S . typhimurium . Analysis of mlrA-lac operon fusions demonstrated that mlrA was positively regulated by rpoS . mlrA mutants of wild-type S . typhimurium SL1344 or SR-11 no longer produced curli or rugose colony morphology, and exhibited enhanced aggregation and extracellular matrix formation when complemented with the mlrA gene from either S . typhimurium or E . coli present on a low-copy-number plasmid . However, inactivation of mlrA did not affect curli production and aggregative morphology in an