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| J Agric Food Chem, 2003 Aug 13, 51(17), 5154 - 61 Preparation of antimicrobial reduced lysozyme compatible in food applications; Touch V et al.; The structural and antimicrobial functions of lysozyme reduced with food-compatible reducing agents-cysteine (Cys) and glutathione (GSH)-were investigated . The disulfide bonds were partially reduced by thiol-disulfide exchange reactions under heat-induced denaturing conditions from 55 to 90 degrees C . The results showed that treatment of lysozyme with Cys and GSH resulted in the introduction of new half-cystine residues (2-3 residues/mol of protein) . The released SH groups, in turn, rendered the lysozyme molecule more flexible, being accompanied by a dramatic increase in the surface hydrophobicity and exposure of tryptophan residues . As a consequence, the resulting reduced lysozymes were more capable of binding to lipopolysaccharides (LPS) and permeabilizing the bacterial outer membrane, as evidenced by the liposome leakage experiment, than were native or heated lysozyme . Both reduced lysozymes displayed significantly higher antimicrobial activity than native or heated lysozyme against Salmonella enteritidis (SE) in sodium phosphate buffer (10 mM, pH 7.2) at 30 degrees C for 1 h . Their minimal inhibitory concentrations (MICs) against the tested bacteria were about 150- and 25-fold lower than their respective MICs of native or heated lysozyme . The results suggest that partially reduced lysozyme could be used as a potential antimicrobial agent for prevention of SE attack. Appl Environ Microbiol, 2003 Aug, 69(8), 4556 - 60 Survival of Salmonella enterica in freshwater and sediments and transmission by the aquatic midge Chironomus tentans (Chironomidae: Diptera); Moore BC et al.; Survival of a nalidixic acid-resistant strain of Salmonella enterica serovar Typhimurium mr-DT-104 in water and sediments was tested using artificially contaminated aquaria . Water samples remained culture positive for salmonella for up to 54 days . Sediment samples were culture positive up to 119 days . In addition, potential mechanisms for spreading salmonella in the environments by chironomid larvae and adults were tested . We evaluated the acquisition of mr-DT-104 by chironomids from contaminated aquatic sediments and subsequent spread to uncontaminated sediments . Larval chironomids raised in contaminated sediments became culture positive, and the bacteria were carried over to adults after emergence . Contamination of clean sediments by chironomid larvae was not demonstrated . These findings clearly suggest that mr-DT-104 serovar organisms can survive in aquatic sediments for at least several months . Uptake of salmonellae by chironomid larvae and adults suggests that they are possible vectors of mr-DT-104 in both aquatic and terrestrial environments, although the role of larval defecation in movement of bacteria to new sediments was not demonstrated. Appl Environ Microbiol, 2003 Aug, 69(8), 4352 - 8 Characterization of the RpoS status of clinical isolates of Salmonella enterica; Robbe-Saule V et al.; The stationary-phase-inducible sigma factor, sigma(S) (RpoS), is the master regulator of the general stress response in Salmonella and is required for virulence in mice . rpoS mutants can frequently be isolated from highly passaged laboratory strains of Salmonella: We examined the rpoS status of 116 human clinical isolates of Salmonella, including 41 Salmonella enterica serotype Typhi strains isolated from blood, 38 S . enterica serotype Typhimurium strains isolated from blood, and 37 Salmonella serotype Typhimurium strains isolated from feces . We examined the abilities of these strains to produce the sigma(S) protein, to express RpoS-dependent catalase activity, and to resist to oxidative stress in the stationary phase of growth . We also carried out complementation experiments with a cloned wild-type rpoS gene . Our results showed that 15 of the 41 Salmonella serotype Typhi isolates were defective in RpoS . We sequenced the rpoS allele of 12 strains . This led to identification of small insertions, deletions, and point mutations resulting in premature stop codons or affecting regions 1 and 2 of sigma(S), showing that the rpoS mutations are not clonal . Thus, mutant rpoS alleles can be found in freshly isolated clinical strains of Salmonella serotype Typhi, and they may affect virulence properties . Interestingly however, no rpoS mutants were found among the 75 Salmonella serotype Typhimurium isolates . Strains that differed in catalase activity and resistance to hydrogen peroxide were found, but the differences were not linked to the rpoS status . This suggests that Salmonella serotype Typhimurium rpoS mutants are counterselected because rpoS plays a role in the pathogenesis of Salmonella serotype Typhimurium in humans or in the transmission cycle of the disease. Chem Biol Interact, 2003 Jul 25, 146(1), 19 - 25 Structural activity relationship between Salmonella-mutagenicity and nitro-orientation of nitroazaphenanthrenes; Tokiwa H et al.; Nitroazaphenanthrenes (NAphs) and their N-oxides (NAphOs) were synthesized as derivatives with nitrogen atoms in the 1, 4, and 9 positions of phenanthrene rings, and as nitrated derivatives substituted at the 1, 2, 3, 4, 5, 6, 7, and 8 positions of phenanthrene rings . To determine the structure activity relationship of these derivatives, all 19 isomers were bioassayed with Salmonella tester strains . NAphs substituted at the 4, 6, 7 and 8 positions were mutagenic for TA98, and 1-, 2-, and 3-N-9-AphOs, 6-N-1-AphO and 6-N-4-AphO were mutagenic for TA98 and TA100 without the S9 mix, while 5-N-1-AphO and 5-N-9-AphO were non- or weakly mutagenic . Nitrated derivatives, 6-N-4-Aph, 6-N-9-Aph, 6-N-1-AphO, and 6-N-4-AphO, were powerful mutagens for TA98 and TA100 . Mutagenicity was enhanced by mutant strains producing nitroreductase, such as YG1021 and 1026, and by those producing O-acetyltransferase, such as YG1024 and 1029 . Nitro derivatives substituted at positions 4 and 5 in the phenanthrene rings were perpendicular, while those at positions 2, 3, 6 and 7 were coplanar to the phenanthrene rings . NAphs substituted at the 1 and 8 positions were noncoplanar due to steric hindrance of the aromatic proton at the peri position . On the other hand, 1,5- and 1,8-dinitro-4-azaphenanthrenes showed high mutagenicity for strains TA98 and TA100 in the absence of the S9 mix, and were strongly enhanced by nitroreductase and O-acetyltransferase, over-producing mutants . Therefore, it was found that the mutagenic potency of NAphs and NAphOs was closely associated with the chemical properties and orientation of nitro substitution of aromatic rings. Expert Rev Vaccines, 2003 Feb, 2(1), 31 - 43 Advances in the development of bacterial vector technology; Kochi SK et al.; The demand for new and improved vaccines against human diseases has continued unabated over the past century . While the need continues for traditional vaccines in areas such as infectious diseases, there is an increasing demand for new therapies in nontraditional areas, such as cancer treatment, bioterrorism and food safety . Prompted by these changes, there has been a renewed interest in the application and development of live, attenuated bacteria expressing foreign antigens as vaccines . The application of bacterial vector vaccines to human maladies has been studied most extensively in attenuted strains of Salmonella . Live, attenuated strains of Shigella, Listeria monocytogenes, Mycobacterium bovis-BCG and Vibrio cholerae provide unique alternatives in terms of antigen delivery and immune presentation, however and also show promise as potentially useful bacterial vectors. Prev Vet Med, 2003 Aug 8, 60(2), 155 - 65 Single versus double testing of meat-juice samples for Salmonella antibodies, in the Danish pig-herd surveillance programme; Ekeroth L et al.; In Denmark, a national serological surveillance-and-control programme for Salmonella in pigs has been in operation since 1995 . The programme is based on the Danish mix-ELISA and uses double testing (two ELISA-wells used per sample) of meat-juice samples taken in relation to slaughter . All herds are classified monthly into one of the three levels; the classification is based on the percentage of positive serological results in the previous 3 months . In connection with evaluation of the programme in 2001, we investigated whether single testing (testing in one well only) could be expected to be sufficiently precise compared to double testing . Data from the year 2000 were used, and mathematical modelling . Single testing was simulated by randomised selection of one of the two results in the double testing . A slight increase in the prevalence of Salmonella-positive samples (1.02-1.09 times more through the four quarters of the year 2000) was found in the simulated single testing, as compared to the double testing . Around 0.5% of the herds would be allocated to another herd level in single testing-almost equal numbers one level up and one level down . No herd being seronegative in double testing would be allocated to levels 2 or 3 (herds with >40 or >70%, respectively, serological reactors) in single testing . The prevalence of "false-positive" diagnoses (positive in single testing and negative in double testing) and inversely defined "false-negative" diagnoses varied from 4.2 to 8.7% and from 3.2 to 4.5%, respectively, through the four quarters of the year 2000 . The probability of allocating a herd to a wrong level due to sampling error was on the average 6.2 (varying from 1.66 to over 100) times higher than the probability of allocating a herd to a wrong level due to the test inaccuracy introduced by going from double to single testing . This is, however, an average; a herd with a true prevalence close to one of the level border cut-offs (40 and 70% weighted seroprevalence, respectively) would have a higher risk of being allocated to a wrong level than a herd with a true prevalence far from the level border cut-offs . The results are based on the current Danish sample sizes in the surveillance scheme, which implies that 60, 75 or 100 samples are taken annually in a herd, depending on its size . Other sample sizes would produce other results. Ann Univ Mariae Curie Sklodowska {Med}, 2002, 57(2), 15 - 20 Foodborne infections and intoxications in the Lublin voivodeship in the years 1980-2000 in comparison with their prevalence in the Polish population; Kalinowski P; The aim of the paper is presentation of foodborne infections and intoxications registered in the Lublin voivodeship in comparison with their nationwide prevalence in the whole country in the years 1980-2000 . The analysed material comprised incidence rates of foodborne infections and intoxications, of which those caused by Salmonellas of animal source, registered in Poland and in the Lublin voivodeship in the studied years . In the analysed period in the Lublin voivodeship and throughout Poland there occurred a huge increase in incidence of foodborne infections and intoxications . The epidemics caused by Salmonella strains to the greatest extent influenced the increase in total number of cases of the disease, caused by deterioration in sanitary situation of the country, hygiene of the society and decline in quality of food of animal origin . The epidemiological situation of the disease in the Lublin voievodship is worse than nationwide average. Ann Univ Mariae Curie Sklodowska {Med}, 2002, 57(2), 9 - 14 Prevalence of infections of the Salmonella strains in the Lublin voivodeship and in Poland in the years 1980-2000; Kalinowski P; The aim of the paper is presentation of the prevalence of infections of the Salmonella strains in the Lublin voivodeship in the years 1980-2000 in comparison with their nationwide prevalence in the same period . The analysed material comprised epidemiological data concerning the incidence rates of salmonelloses registered in Poland in the studied period . Since the beginning of the 1980s there was observed a constantly increasing trend in incidence rates of salmonelloses . After 1988 throughout Poland and after 1990 in the Lublin voivodeship there was noted gradual decline in incidence of infections caused by Salmonellas . Administrative decisions and recent improvements in sanitary situation in our country caused appearance of that favourable, decreasing trend of incidence rates of salmonelloses . The statistics concerning extraintestinal infections with Salmonellas are still unreliable, especially in the Lublin voivodeship. Mol Genet Genomics, 2003 Oct, 270(1), 56 - 65 Epub 2003 Jul 30. The gyr genes of Salmonella enterica serovar Typhimurium are repressed by the factor for inversion stimulation, Fis; Keane OM et al.; The DNA sequence of the gyr genes from Salmonella enterica serovar Typhimurium revealed strong similarity between gyrB and its counterpart in Escherichia coli . However, the gyrA gene showed similarity to the E . coli homologue only downstream from the Pribnow box of the promoter, with the sequence upstream diverging markedly . Since this region encompasses the binding sites for the Fis DNA binding protein in E . coli, we investigated the possibility that the gyrA genes in the two species might differ in their responses to this regulatory protein . Fis was found to act as a transcriptional repressor of both gyr genes in S . enterica . In electrophoretic mobility shift assays, Fis was found to bind to both the gyrA and gyrB promoters of S . enterica, despite the strong divergence from the E . coli sequence on the part of the former . The binding sites were mapped by DNase I protection assays, and the results are consistent with conservation of the mechanism of Fis-mediated repression between the two bacterial species. Can J Microbiol, 2003 May, 49(5), 326 - 35 Prevalence of Escherichia coli O157:H7 and Salmonella spp . in surface waters of southern Alberta and its relation to manure sources; Johnson JY et al.; The Oldman River watershed in southern Alberta, Canada, is an extensively irrigated region in which intensive agricultural practices have flourished . Concern over water quality in the basin has been expressed because of high levels of enteric disease indigenous to the region . To address these concerns, we conducted a 2-year study to estimate the prevalence of Escherichia coli O157:H7 and Salmonella spp . in surface water within the basin . This study is the first of its kind to identify E . coli O157:H7 repeatedly in surface water collected from a Canadian watershed . Prevalence of E . coli O157:H7 and Salmonella spp . in water samples was 0.9% (n = 1,483) and 6.2% (n = 1,429), respectively . While data examined at a regional level show a relationship between high livestock density and high pathogen levels in southern Alberta, statistical analysis of point source data indicates that predicted manure output from bovine, swine, and poultry feeding operations was not directly associated with either Salmonella spp . or E . coli O157:H7 prevalence . However, geography and weather variables, which are likely to influence bacterial runoff, were not considered in this model . We also postulate that variations in time, amount, and frequency of manure application onto agricultural lands may have influenced levels of surface-water contamination with these bacterial pathogens. J Bacteriol, 2003 Aug, 185(16), 4973 - 82 Genomic profiling of iron-responsive genes in Salmonella enterica serovar typhimurium by high-throughput screening of a random promoter library; Bjarnason J et al.; The importance of iron to bacteria is shown by the presence of numerous iron-scavenging and transport systems and by many genes whose expression is tightly regulated by iron availability . We have taken a global approach to gene expression analysis of Salmonella enterica serovar Typhimurium in response to iron by combining efficient, high-throughput methods with sensitive, luminescent reporting of gene expression using a random promoter library . Real-time expression profiles of the library were generated under low- and high-iron conditions to identify iron-regulated promoters, including a number of previously identified genes . Our results indicate that approximately 7% of the genome may be regulated directly or indirectly by iron . Further analysis of these clones using a Fur titration assay revealed three separate classes of genes; two of these classes consist of Fur-regulated genes . A third class was Fur independent and included both negatively and positively iron-responsive genes . These may reflect new iron-dependent regulons . Iron-responsive genes included iron transporters, iron storage and mobility proteins, iron-containing proteins (redox proteins, oxidoreductases, and cytochromes), transcriptional regulators, and the energy transducer tonB . By identifying a wide variety of iron-responsive genes, we extend our understanding of the global effect of iron availability on gene expression in the bacterial cell. J Bacteriol, 2003 Aug, 185(16), 4837 - 43 Residues C123 and D58 of the 2-methylisocitrate lyase (PrpB) enzyme of Salmonella enterica are essential for catalysis; Grimek TL et al.; The prpB gene of Salmonella enterica serovar Typhimurium LT2 encodes a protein with 2-methylisocitrate (2-MIC) lyase activity, which cleaves 2-MIC into pyruvate and succinate during the conversion of propionate to pyruvate via the 2-methylcitric acid cycle . This paper reports the isolation and kinetic characterization of wild-type and five mutant PrpB proteins . Wild-type PrpB protein had a molecular mass of approximately 32 kDa per subunit, and the biologically active enzyme was comprised of four subunits . Optimal 2-MIC lyase activity was measured at pH 7.5 and 50 degrees C, and the reaction required Mg(2+) ions; equimolar concentrations of Mn(2+) ions were a poor substitute for Mg(2+) (28% specific activity) . Dithiothreitol (DTT) or reduced glutathione (GSH) was required for optimal activity; the role of DTT or GSH was apparently not to reduce disulfide bonds, since the disulfide-specific reducing agent Tris(2-carboxyethyl)phosphine hydrochloride failed to substitute for DTT or GSH . The K(m) of PrpB for 2-MIC was measured at 19 micro M, with a k(cat) of 105 s(-1) . Mutations in the prpB gene were introduced by site-directed mutagenesis based on the active-site residues deemed important for catalysis in the closely related phosphoenolpyruvate mutase and isocitrate lyase enzymes . Residues D58, K121, C123, and H125 of PrpB were changed to alanine, and residue R122 was changed to lysine . Nondenaturing polyacrylamide gel electrophoresis indicated that all mutant PrpB proteins retained the same oligomeric state of the wild-type enzyme, which is known to form tetramers . The PrpB(K121A), PrpB(H125A), and PrpB(R122K) mutant proteins formed enzymes that had 1,050-, 750-, and 2-fold decreases in k(cat) for 2-MIC lyase activity, respectively . The PrpB(D58A) and PrpB(C123A) proteins formed tetramers that displayed no detectable 2-MIC lyase activity indicating that both of these residues are essential for catalysis . Based on the proposed mechanism of the closely related isocitrate lyases, PrpB residue C123 is proposed to serve as the active site base, and residue D58 is critical for the coordination of a required Mg(2+) ion. J Bacteriol, 2003 Aug, 185(16), 4748 - 54 DapE can function as an aspartyl peptidase in the presence of Mn2+; Broder DH et al.; Extracts of a multiply peptidase-deficient (pepNABDPQTE iadA iaaA) Salmonella enterica serovar Typhimurium strain contain an aspartyl dipeptidase activity that is dependent on Mn(2+) . Purification of this activity followed by N-terminal sequencing of the protein suggested that the Mn(2+)-dependent peptidase is DapE (N-succinyl-L,L-diaminopimelate desuccinylase) . A dapE chromosomal disruption was constructed and transduced into a multiply peptidase-deficient (MPD) strain . Crude extracts of this strain showed no aspartyl peptidase activity, and the strain failed to utilize Asp-Leu as a leucine source . The dapE gene was cloned into expression vectors in order to overproduce either the native protein (DapE) or a hexahistidine fusion protein (DapE-His(6)) . Extracts of a strain carrying the plasmid overexpresssing native DapE in the MPD dapE background showed a 3,200-fold elevation of Mn(2+)-dependent aspartyl peptidase activity relative to the MPD dapE(+) strain . In addition, purified DapE-His(6) exhibited Mn(2+)-dependent peptidase activity toward aspartyl dipeptides . Growth of the MPD strain carrying a single genomic copy of dapE on Asp-Leu as a Leu source was slow but detectable . Overproduction of DapE in the MPD dapE strain allowed growth on Asp-Leu at a much faster rate . DapE was found to be specific for N-terminal aspartyl dipeptides: no N-terminal Glu, Met, or Leu peptides were hydrolyzed, nor were any peptides containing more than two amino acids . DapE is known to bind two divalent cations: one with high affinity and the other with lower affinity . Our data indicate that the form of DapE active as a peptidase contains Zn(2+) in the high-affinity site and Mn(2+) in the low-affinity site. Eur J Cardiothorac Surg, 2003 Aug, 24(2), 320 - 2 Successful treatment of Salmonella mycotic aneurysm of the descending thoracic aorta; Lin CY et al.; Salmonella mycotic aneurysms of the descending thoracic aorta are exceedingly rare . There are few case reports and even fewer reports of long term survival . The case of a 68-year-old female presenting with a mycotic aneurysm of the descending thoracic aorta caused by Salmonella species is described, which involved successful surgical intervention. Berl Munch Tierarztl Wochenschr, 2003 Jul-Aug, 116(7-8), 293 - 8 {Intracellular survival of Salmonella strains in Caco-2 cells}; Dinjus U et al.; In the in vitro model using Caco-2 cells at different stages of differentiation the invasion and intracellular survival of virulent (predominant infection strains) and less virulent (predominant attenuated mutant strains) Salmonella strains were studied . The statistical evaluation of experimental data has shown that the logarithmized colony forming unit after 18 hours of incubation in differentiated cells (14 days old) is a suitable parameter for the determination of intracellular survival . Using this parameter a relationship between intracellular survival and Salmonella virulence (LD50 mouse) was demonstrated and quantified . The model presented could be suitable for the replacement of animal experiments after further investigations. Berl Munch Tierarztl Wochenschr, 2003 Jul-Aug, 116(7-8), 281 - 7 {Usefulness of serological examinations in the analysis of Salmonella infections in pig herds}; Steinbach G et al.; The development of the antibody concentration against lipopolysaccharide (LPS) of S . Typhimurium und S . Choleraesuis in rearing pigs during the fattening period and in breeding sows of the corresponding age was recorded . The studies revealed the following results . Antibodies of isotypes IgG1 and IgG2 revealed a more pronounced specificity against the according Salmonella serovar than IgM antibodies . The calculated "antibody percent value" based on the total amount of Salmonella antibodies is mainly determined by the IgM antibodies in sera and meat juice, respectively . In fattening pigs a significant increase of antibodies against IgM and total Ig was observed between week 3 and 10 after beginning of the rearing period . In breeding pigs this increase was detectable already earlier . In only 3 out of 10 groups an increase of IgG1 and IgG2 was also seen . The detected significant increase of total Ig and IgM in the other groups might be the result of a less intensive exposure to salmonellas or it might be due to an increase of unspecific antibodies induced by other antigens . Serological investigations represent a valuable tool to record the intensity and development in time of the Salmonella exposure in pigs farms . Examination of total Ig is an appropriate method to detect pig herds with a high level of Salmonella exposure, for detailed epidemiological studies in pig farms the examination of antibody isotypes will give more comprehensive information. FEMS Microbiol Lett, 2003 Jul 29, 224(2), 291 - 7 msDNA-St85, a multicopy single-stranded DNA isolated from Salmonella enterica serovar Typhimurium LT2 with the genomic analysis of its retron; Ahmed AM et al.; Bacterial reverse transcriptase is responsible for the production of a small satellite DNA-RNA complex called multicopy single-stranded DNA (msDNA) that has been found in a wide variety of Gram-negative bacteria . Here we describe the isolation and characterization of a novel msDNA, msDNA-St85, from Salmonella enterica serovar Typhimurium LT2 . We determined the nucleotide sequence of msDNA-St85 and the location of retron-St85 on the chromosome that is responsible for msDNA-St85 production by analyzing the complete genomic sequence of S . typhimurium LT2 . It was found that the G+C content and the codon usage of retron-St85 were significantly different from those of the S . typhimurium genome, indicating that retron-St85 was probably acquired recently in this bacterium . This is the first report for identification of an msDNA in the genus Salmonella with the complete description and analysis of its retron. FEMS Microbiol Lett, 2003 Jul 29, 224(2), 239 - 46 Identification of the CysB-regulated gene, hslJ, related to the Escherichia coli novobiocin resistance phenotype; Lilic M et al.; The cysB gene product is a LysR-type regulatory protein required for expression of the cys regulon . cysB mutants of Escherichia coli and Salmonella, along with being auxotrophs for the cysteine, exhibit increased resistance to the antibiotics novobiocin (Nov) and mecillinam . In this work, by using lambdaplacMu9 insertions creating random lacZ fusions, we identify a gene, hslJ, whose expression appeared to be increased in cysB mutants and needed for Nov resistance . Measurements of the HSLJ::lacZ gene fusion expression demonstrated that the hslJ gene is negatively regulated by CysB . In addition we observe the negative autogenous control of HslJ . When the control imposed by CysB is lifted in the cysB mutant, the elevation of Nov resistance can be achieved only in the presence of wild-type hslJ allele . A double cysB hslJ mutant restores the sensitivity to Nov . Overexpression of the wild-type HslJ protein either in a cysB(+) or a cysB(-) background increases the level of Nov resistance indicating that hslJ product is indeed involved in accomplishing this phenotype . The HSLJ::OmegaKan allele encodes the C-terminaly truncated mutant protein HslJ Q121Ter which is not functional in achieving the Nov resistance but when overexpressed induces the psp operon . Finally, we found that inactivation of hslJ does not affect the increased resistance to mecillinam in cysB mutants. Emerg Infect Dis, 2003 Jul, 9(7), 774 - 80 Salmonella control programs in Denmark; Wegener HC et al.; We describe Salmonella control programs of broiler chickens, layer hens, and pigs in Denmark . Major reductions in the incidence of foodborne human salmonellosis have occurred by integrated control of farms and food processing plants . Disease control has been achieved by monitoring the herds and flocks, eliminating infected animals, and diversifying animals (animals and products are processed differently depending on Salmonella status) and animal food products according to the determined risk . In 2001, the Danish society saved U.S.$25.5 million by controlling Salmonella . The total annual Salmonella control costs in year 2001 were U.S.$14.1 million (U.S.$0.075/kg of pork and U.S.$0.02/kg of broiler or egg) . These costs are paid almost exclusively by the industry . The control principles described are applicable to most industrialized countries with modern intensive farming systems. Can J Vet Res, 2003 Jul, 67(3), 219 - 24 Comparison of bacterial enriched-broth culture, enzyme linked immunosorbent assay, and broth culture-polymerase chain reaction techniques for identifying asymptomatic infections with Salmonella in swine; Sibley J et al.; A polymerase chain reaction (PCR) assay was combined with a broth-culture enrichment system to detect Salmonella shed in feces from subclinically infected swine . The effectiveness of the broth culture-polymerase chain reaction (BC-PCR) assay to identify pigs shedding Salmonella in feces was compared with a microbiological culture and a commercial enzyme linked immunosorbent assay (ELISA) kit to detect Salmonella-specific serum antibody . A total of 67 pigs were tested by each of the 3 methodologies . Forty-one pigs tested positive for Salmonella by BC-PCR and ELISA identified 6 positives and 23 suspicious samples . It was shown that the BC-PCR assay is a rapid diagnostic tool for detecting of Salmonella shed by asymptomatic swine compared with current diagnostic technologies. Scand J Gastroenterol, 2003 Jul, 38(7), 719 - 26 Luminal salmonella endotoxin affects epithelial and mast cell function in the proximal colon of pigs; Aschenbach JR et al.; BACKGROUND: Salmonellosis and systemic endotoxaemia affect intestinal function . However, little is known about the functional importance of luminal Salmonella (S.) endotoxin during intestinal infection . METHODS: Pigs were either given or not given lipopolysaccharide (LPS, 30 mg day(-1)) of S . Typhimurium DT-104 orally for 14 days . Blood samples were taken weekly . After slaughter (day 14), epithelia of the proximal colon were investigated in Ussing chambers . Bacterial translocations to lung, liver, spleen and several lymph nodes were determined by culture . RESULTS: Endotoxin feeding increased plasma C-reactive protein (CRP) and histamine levels without evoking clinical signs . Postmortem, proximal colonic epithelia of LPS-treated animals showed both a decreased histamine release after mast cell stimulation with A23187 and a smaller increase in short-circuit current after A23187 application . Addition of the nitric oxide donor, sodium nitroprusside (SNP), also elicited lower increases in short-circuit current in the proximal colon of endotoxin-treated pigs . Endotoxin pre-feeding decreased colonic ion conductance, although mannitol and histamine fluxes were high in some epithelia of this group . Luminal Salmonella endotoxin increased bacterial translocation to proximal jejunal lymph nodes . LPS applied to colonic epithelia in vitro had no electrophysiological effects . CONCLUSIONS: Luminal endotoxin elicits an acute phase response and affects intestinal electrolyte transport and mast cell function . Furthermore, LPS induces epithelial spots of increased mannitol permeability that could be identical to spots of enhanced bacterial translocation. Biotechnol Bioeng, 2003 Sep 20, 83(6), 721 - 8 Detection and identification of Escherichia coli, Shigella, and Salmonella by microarrays using the gyrB gene; Kakinuma K et al.; Commonly, 16S ribosome RNA (16S rRNA) sequence analysis has been used for identifying enteric bacteria . However, it may not always be applicable for distinguishing closely related bacteria . Therefore, we selected gyrB genes that encode the subunit B protein of DNA gyrase (a topoisomerase type II protein) as target genes . The molecular evolution rate of gyrB genes is higher than that of 16S rRNA, and gyrB genes are distributed universally among bacterial species . Microarray technology includes the methods of arraying cDNA or oligonucleotides on substrates such as glass slides while acquiring a lot of information simultaneously . Thus, it is possible to identify the enteric bacteria easily using microarray technology . We devised a simple method of rapidly identifying bacterial species through the combined use of gyrB genes and microarrays . Closely related bacteria were not identified at the species level using 16S rRNA sequence analysis, whereas they were identified at the species level based on the reaction patterns of oligonucleotides on our microarrays using gyrB genes . Nucleic Acids Res, 2003 Aug 1, 31(15), 4517 - 22 Transcription increases multiple spontaneous point mutations in Salmonella enterica; Hudson RE et al.; The spontaneous rate of G.C-->A.T mutations and a hotspot T.A-->G.C transversion are known to increase with the frequency of transcription-increases that have been ascribed primarily to processes that affect only these specific mutations . To investigate how transcription induces other spontaneous point mutations, we tested for its effects in repair-proficient Salmonella enterica using reversion assays of chromosomally inserted alleles . Our results indicate that transcription increases rates of all tested point mutations in the induced gene: induction significantly increased the individual rates of an A.T-->T.A transversion, an A.T-->G.C transition and the pooled rates of the three other point mutations assayed . Although the S.enterica genome is thought to have a mutational bias towards G.C base pairs, transitions creating A.T pairs were approximately 10 times more frequent than the reverse mutation, resulting in an overall mutation pressure to lower G+C contents . Transitions occurred at roughly twice the rate of transversions, similar to results from sequence comparisons; however, several individual transversions are more frequent than the least common transition. Avian Dis, 2003 Apr-Jun, 47(2), 387 - 95 A restriction fragment length polymorphism-based polymerase chain reaction as an alternative to serotyping for identifying Salmonella serotypes; Hong Y et al.; The phase 1 (fliC) and phase 2 (fljB) Salmonella flagella genes were analyzed by restriction fragment length polymorphism (RFLP)-polymerase chain reaction (PCR) to aid in the identification of different Salmonella serotypes . Twenty-four phase 1 flagellin and eight phase 2 flagellin genes could be differentiated among each other with restriction endonucleases Sau3A and HhaI in RFLP-PCR analysis . These flagellin genes comprise the major antigenic formulas for 52 serotypes of Salmonella sp., which include the common serotypes found in poultry and other important food animal species . With the knowledge of the O antigen composition determined from conventional O serotyping, 90% of the Salmonella serotypes could be identified by this double restriction enzyme RFLP analysis of fliC and fljB genes . This RFLP-PCR flagellar typing scheme was successfully applied to the identification of serotype for 112 Salmonella isolates obtained from poultry environment . There was a significant correlation between RFLP-PCR and conventional serotyping (chi-square, P < 0.001) . Overall, PCR-RFLP proved to be a fast, accurate, and economical alternative approach to serotyping Salmonella sp. Avian Dis, 2003 Apr-Jun, 47(2), 380 - 6 Rapid detection of Salmonella from poultry by real-time polymerase chain reaction with fluorescent hybridization probes; Eyigor A et al.; Detection of Salmonella by bacteriologic methods is known to be time consuming . Therefore, we have developed a real-time probe-specific polymerase chain reaction (PCR) to rapidly detect Salmonella invA gene-based PCR products from chicken feces and carcasses by a fluorescence resonance energy transfer assay . The sensitivity and the specificity of this system were determined as 3 colony-forming units ml(-1) and 100%, respectively . Overnight tetrathionate broth enrichment cultures of chicken feces and carcass samples were used in template preparation for PCR . Also, a standard bacteriology was performed (National Poultry Improvement Plan-U.S . Department of Agriculture, Bacteriological Analytical Manual-Food and Drug Administration Center for Food Safety and Applied Nutrition) for confirmation . Seventy-two cloacal swab, 147 intestine, and 50 carcass (neck) samples were examined . Thirteen (8.8%) and 25 (17%) of the intestinal samples were found to harbor Salmonella by bacteriology and PCR, respectively . Forty-five of 50 (90%) carcass samples were Salmonella positive by both methods . Salmonella was not detected from cloacal swab samples . Results indicate that this assay has the potential for use in routine monitoring and detection of Salmonella in infected flocks and carcasses. Anim Biotechnol, 2003 May, 14(1), 61 - 76 Candidate gene approach: potentional association of caspase-1, inhibitor of apoptosis protein-1, and prosaposin gene polymorphisms with response to Salmonella enteritidis challenge or vaccination in young chicks; Liu W et al.; Salmonella enteritidis (SE) contamination of poultry products is a major cause of foodborne disease worldwide . Caspase-1 and inhibitor of apoptosis protein-1 (IAP-1) were selected as candidate genes for chicken response to SE because their proteins play critical roles in the apoptotic pathway when intracellular bacteria interact with host cells . Prosaposin (PSAP) was selected as a positional candidate gene based on a previous quantitative trait loci (QTL) linkage study using the same population . The F1 offspring of outbred sires crossed with three diverse, highly inbred dam lines (two major histocompatibility complex-congenic Leghorn lines named G-B1 and G-B2, and one Fayoumi line) were used to define the phenotypes . The F1 birds were involved in either pathogenic SE challenge, in which spleen and cecum content bacterial load were quantified, or SE vaccination, in which plasma antibody level to SE vaccine was evaluated . A polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) assay was developed to identify single-nucleotide polymorphism (SNP) in the three genes . The F1 offspring of heterozygous sires for each gene were genotyped . The sire caspase-1 gene was significantly associated with cecum content bacterial load (P = 0.04) in the three combined dam line crosses, and with spleen bacterial load in the G-B1 cross (P=0.02) . The sire caspase-1 gene was also significantly associated with antibody level to SE vaccine (P=0.03) in F1 males in the three combined dam line crosses . The sire IAP-1 gene was significantly associated with spleen bacterial load (P=0.04) in the three combined dam-line crosses, and interacted with dam-line genetics (P = 0.01) for cecum content bacterial load . The sire PSAP gene significantly interacted with sex for spleen bacterial load (P = 0.004) . This study is the first to demonstrate the association of SNPs for caspase-1, IAP-1, and PSAP genes with SE vaccine and with pathogen challenge response in chickens. Zh Mikrobiol Epidemiol Immunobiol, 2003 May-Jun, (3), 79 - 80 {Detection of lymphocytes binding erythrocytes conjugated with Salmonella antigens}; Denisova TG et al.; Immune reagents for the detection of specific antigen-binding lymphocytes (ABL) with respect to different Salmonells antigens were developed . Rabbits were immunized with killed S . typhi and other salmonellae containing cross-reacting antigens, and the dynamics of the formation of ASL of each specificity was studied . Differences in the time of the appearance of ASL with receptors to thymus-independent (09, 12 or Vi) and thymus-dependent (Hd) antigens were studied . The relative content of ASL, determined with the use of immune reagents prepared from S . typhi antigens, was higher, on the whole, in rabbits immunized with S . typhi than in rabbits immunized with salmonellae containing one of cross-reacting antigens (S . enteritidis--09, 12; S . paratyphi C--Vi; S . virginia--Hd). Mem Inst Oswaldo Cruz, 2003 Apr, 98(3), 419 - 23 Epub 2003 Jul 18. The effect of nitric oxide combined with fluoroquinolones against Salmonella enterica serovar Typhimurium in vitro; Coban AY et al.; Two regulons, soxRS and marRAB, are associated with resistance to quinolones or multiple antibiotic in Salmonella enterica serovar Typhimurium . These regulons are activated by nitric oxide and redox-cycling drugs, such as paraquat and cause on activation of the acrAB-encoded efflux pump . In this study, we investigated the effect of nitric oxide (NO) alone and in combination with ofloxacin, ciprofloxacin, and pefloxacin against S . typhimurium clinical isolates and mutant strains in vitro . We did not observe synergistic effect against clinical isolates and SH5014 (parent strain of acr mutant), while we found synergistic effect against PP120 (soxRS mutant) and SH7616 (an acr mutant) S . typhimurium for all quinolones . Our results suggest that the efficiencies of some antibiotics, including ofloxacin, ciprofloxacin, and pefloxacin are decreased via activation of soxRS and marRAB regulons by NO in S . enterica serovar Typhimurium . Further studies are warranted to establish the interaction of NO with the genes of Salmonella and, with multiple antibiotic resistance. Folia Microbiol (Praha), 2003, 48(3), 339 - 45 Is Pseudobutyrivibrio xylanivorans strain Mz5T suitable as a probiotic? An in vitro study; Cepeljnik T et al.; Rumen bacterium Pseudobutyrivibrio xylanivorans strain Mz5T possessed a potent xylanolytic enzyme system consisting of at least 7 different xylan hydrolases with molar mass 27-145 kDa . Three of them were successfully isolated in active native form . This strain produced butyrate and lactate on different saccharides . cis-9, trans-11-Conjugated linoleic acid was also detected in the culture medium . Bacteriocin-like inhibitory substances of Mz5T were active against some strains of rumen bacteria and against selected Salmonella and E . coli isolates from poultry meat . The strain Mz5T retained viability and xylanolytic activity also under not fully anaerobic conditions; its cells attached to the Caco-2 cells so that its successful association with gut epithelial cells may be expected . These in vitro results confirmed several probiotic traits of the isolate Mz5T and justified further in vivo experiments to test its ability to improve animal health and performance. Arkh Patol, 2003 May-Jun, 65(3), 36 - 8 {Proliferative processes in the epithelium of colon mucosa in patients with Salmonella infection during first 24 hours after the onset of the disease}; Mokretsova EV et al.; DNA synthesis in the epithelium of a distal portion of human colon was studied by radioautography with 3H-thymidine in patients during the first 24 hours of gastrointestinal salmonellosis . All 13 patients aged 18-50 years were admitted to hospital during 9-20 hours after the disease onset . Nobody had a background of gastrointestinal pathology . The control group consisted of samples from sigmoid colon epithelium of 30 healthy individuals . The labelled nuclei index (LNI) was 5.16 +/- 0.27%, the intensity of labelling (IL) was 13.65x +/- 0.82 . Endoscopic and pathomorphological studies of colonic mucosa in salmonellosis by the end of the first 24 hours of the disease showed superficial inflammation . Increased LNI (11.48 +/- 1.07%, p < 0.05) characterized activation of proliferation and increased IL (22.24 +/- 2.1, p < 0.05) showed intensification of DNA synthesis . Additionally, in one third of cases enlargement of proliferation compartment up to 2/3 crypt was noticed . It is unlikely that in this situation immune mechanisms play the key role, it seems that a direct stimulation of proliferative processes by a bacterial agent takes place. Neuroradiology, 2003 Aug, 45(8), 541 - 5 Epub 2003 Jul 16. Extracranial internal carotid artery Salmonella mycotic aneurysm complicated by occlusion of the internal carotid artery: depiction by color Doppler sonography, CT and DSA; Sidiropoulou MS et al.; Mycotic aneurysms of the extracranial carotid artery are rare . Seventy-four cases have been described in the medical literature and only eight secondary to Salmonella infection . To our knowledge, color Doppler sonography, computed tomography (CT), and digital subtraction angiography (DSA) findings relating to the diagnosis and follow-up of extracranial internal carotid artery mycotic aneurysm complicated by occlusion have not previously been described in the literature . We present a report of color Doppler sonography, CT, and DSA findings of a mycotic aneurysm of the right extracranial internal carotid artery due to Salmonella associated with occlusion of the internal carotid artery, promptly diagnosed and followed up using these imaging modalities. Ann Hematol, 2003 Oct, 82(10), 646 - 8 Epub 2003 Jul 22. Suppurative salmonella thyroiditis in a patient with chronic lymphocytic leukemia; Dai MS et al.; We describe an 82-year-old man with undiagnosed chronic lymphocytic leukemia (CLL) who presented with acute swelling of the thyroid goiter . Subsequent thyroid aspirate and blood culture yielded group B Salmonella thyroid abscess with septicemia . Infectious complications are the major cause of morbidity and mortality in patients with CLL since most of them can be timely detected and few can arise from innocent-looking lesions. Int J Food Microbiol, 2003 Aug 25, 85(3), 237 - 48 Invasion of Salmonella enteritidis in avian intestinal epithelial cells in vitro is influenced by short-chain fatty acids; Van Immerseel F et al.; Fermentation reactions in the caeca of chickens, the predominant place for Salmonella colonization, result in high concentrations of short-chain fatty acids (SCFA) . Thus Salmonella bacteria are in close contact with SCFA during their life cycle . A study was carried out to analyse the effects of SCFA on invasion of Salmonella enteritidis in an avian intestinal epithelial cell line . Preincubation of S . enteritidis for 4 h in growth media supplemented with various concentrations of propionate or butyrate resulted in decreased invasion compared to bacteria, preincubated in nonsupplemented media, and to bacteria, preincubated in media supplemented with formate or acetate . Incubation of the S . enteritidis bacteria in media supplemented with mixtures of SCFA mimicking the in vivo caecal concentrations resulted in increased invasion compared with butyrate-exposed bacteria, but equal invasion compared with nonexposed bacteria . Increasing the butyrate concentration in these mixtures did not modify invasion compared with the original mixtures. Am J Pathol, 2003 Aug, 163(2), 711 - 21 An angiogenic switch in macrophages involving synergy between Toll-like receptors 2, 4, 7, and 9 and adenosine A(2A) receptors; Pinhal-Enfield G et al.; Adenosine A(2A) receptor (A(2A)R) agonists synergize with Escherichia coli (E . coli) LPS {toll-like receptor (TLR)4 agonist} to up-regulate vascular endothelial growth factor (VEGF) expression in murine macrophages . Here, we demonstrate that TLR2, TLR7, and TLR9, but not TLR3 and TLR5 agonists, also synergize with A(2A)R agonists and adenosine to up-regulate VEGF, while simultaneously strongly down-regulating TNFalpha expression . In the absence of adenosine or A(2A)R agonists, Porphyromonas gingivalis (P . gingivalis) LPS and PAM(3)CAG (TLR2 agonists), resiquimod (R848) (TLR7 agonist), and non-methylated CpG DNA (TLR9 agonist) strongly up-regulate TNFalpha expression, with no effect on VEGF . In the presence of adenosine or A(2A)R agonists, but not A(1)R agonists, TLR2, 4, 7, and 9 agonists strongly up-regulate VEGF expression, while simultaneously down-regulating TNFalpha . C57BL/10ScN (TLR4 deletion mutant) macrophages produce TNFalpha in response to TLR2, 3, 7, and 9 agonists, but not the TLR4 agonist E . coli LPS . With adenosine or A(2A)R agonists, TLR2, 7, and 9, but not TLR4 agonists, also synergistically up-regulate VEGF, while down-regulating TNFalpha expression . Polyinosinic-polycytidilic acid (poly(I:C)) (TLR3 agonist) stimulates TNFalpha expression in macrophages from both C57BL/10ScSn and C57BL/10ScN mice, but has little effect on VEGF expression in the presence of adenosine or A(2A)R agonists . R-flagellins from Serratia marcescens (S . marcescens) and Salmonella muenchen (S . muenchen) do not stimulate TNFalpha expression in either C57BL/10ScSn or C57BL10/ScN mice, and have no effect on VEGF production in the presence of adenosine or A(2A)R agonists . While adenosine and A(2A)R agonists strongly down-regulate TNFalpha protein expression induced by TLR2, 3, 4, 7, and 9 agonists, TNFalpha mRNA and NF-kappaB activation are not reduced . We propose a novel signaling pathway in murine macrophages involving synergy between TLRs 2, 4, 7, and 9 and A(2A)Rs, that up-regulates VEGF and down-regulates TNFalpha expression, thus acting as an angiogenic switch . This angiogenic switch may play an important role in ischemia when TLR agonists are present, providing an interface between innate immunity and wound healing. Infect Immun, 2003 Aug, 71(8), 4795 - 803 Secreted effector proteins of Salmonella enterica serotype typhimurium elicit host-specific chemokine profiles in animal models of typhoid fever and enterocolitis; Zhang S et al.; Infection of bovine ligated loops with the Salmonella enterica serotype Typhimurium wild type but not a sipA sopABDE2 mutant resulted in fluid accumulation, polymorphonuclear cell infiltration, and expression of CXC chemokines, particularly GRO alpha . None of these sipA sopABDE2-dependent responses was observed in murine-ligated loops . The majority of GRO alpha transcripts localized to bovine intestinal epithelium . Thus, different disease outcomes between mice (i.e., no diarrhea) and calves (i.e., diarrhea) may be due to differences in sipA sopABDE2-dependent CXC chemokine gene expression in epithelial cells. Infect Immun, 2003 Aug, 71(8), 4733 - 41 Induction of antimicrobial pathways during early-phase immune response to Salmonella spp . in murine macrophages: gamma interferon (IFN-gamma) and upregulation of IFN-gamma receptor alpha expression are required for NADPH phagocytic oxidase gp91-stimulated oxidative burst and control of virulent Salmonella spp; Foster N et al.; The effect of gamma interferon (IFN-gamma) on elevation of reactive oxygen species and the viability of virulent wild-type and avirulent mutants of Salmonella enterica serovar Typhimurium and S . enterica serovar Infantis was studied in a murine macrophage cell line (J774.2 cells) . S . enterica serovar Typhimurium 14028 phoP and a rough lipopolysaccharide mutant of S . enterica serovar Infantis 1326/28 (phi(r)) (avirulent mutants) induced NADPH phagocytic oxidase gp91 (gp91(phox)) activity and a significant (P < 0.05) elevation of reactive oxygen species within 12 h without coculture with IFN-gamma . This coincided with reduced survival of S . enterica serovar Typhimurium14028 phoP or stasis of S . enterica serovar Infantis phi(r) . Fluorometric studies indicated that expression of IFN-gamma on infected J774.2 cells was not significantly (P > 0.05) elevated . However, studies with the virulent S . enterica serovar Typhimurium strains showed that a comparable level of control of bacterial numbers could only be achieved by coculture with IFN-gamma . This coincided with significant upregulation of IFN-gamma receptor alpha expression on the surface of J774.2 cells and was completely abolished by N-acetyl-L-cysteine captopril (an inhibitor of reactive oxygen species) . Delay in reactive oxygen species induction due to a requirement for IFN-gamma and upregulation of IFN-gamma receptor alpha in macrophages infected with virulent salmonellae may result in greater dissemination of virulent salmonellae in host tissue. Infect Immun, 2003 Aug, 71(8), 4664 - 73 Construction, characterization, and immunogenicity of an attenuated Salmonella enterica serovar typhimurium pgtE vaccine expressing fimbriae with integrated viral epitopes from the spiC promoter; Chen H et al.; Transmissible gastroenteritis virus (TGEV) is a porcine coronavirus that causes diarrhea, leading to near 100% mortality in neonatal piglets with corresponding devastating economic consequences . For the protection of neonatal and older animals, oral live vaccines present the attractive property of inducing desired mucosal immune responses, including colostral antibodies in sows--an effective means to passively protect suckling piglets . Newly attenuated Salmonella vaccine constructs expressing TGEV S protein epitopes were studied and evaluated for improved humoral immune response to TGEV . The macrophage-inducible Salmonella ssaH and spiC/ssaB promoters were compared for their ability to express the TGEV C and A epitopes in the context of the heterologous 987P fimbriae on Salmonella vaccines . Compared to the ssaH promoter, the Salmonella cya crp vector elicited significantly higher levels of mucosal and systemic antibodies in orally immunized mice when the chimeric fimbriae were expressed from the spiC promoter . The Salmonella spiC promoter construct induced the highest level of chimeric fimbriae after being taken up by the J774A.1 macrophagelike cells . The Salmonella cya crp vaccine vector was shown to incorporate into 987P partially degraded chimeric subunits lacking the TGEV epitopes . In contrast, its isogenic pgtE mutant produced fimbriae consisting exclusively of intact chimeric subunits . Mice immunized orally with the Salmonella pgtE vaccine expressing chimeric fimbriae from the spiC promoter elicited significantly higher systemic and mucosal antibody titers against the TGEV epitopes compared to the parental vaccine . This study indicates that the Salmonella cya crp pgtE vector and the spiC promoter can be used successfully to improve immune responses toward heterologous antigens. Infect Immun, 2003 Aug, 71(8), 4382 - 8 Human alveolar macrophages infected by virulent bacteria expressing SipB are a major source of active interleukin-18; Obregon C et al.; Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form . Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death . Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens . Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes . Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model . Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated . In contrast, the sipB mutant did not induce such cell death or the release of active IL-18 . The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain . However, the type of Salmonella infection did not differentially regulate IL-18 gene expression . We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM. Poult Sci, 2003 Jul, 82(7), 1170 - 3 Invasion of Salmonella enteritidis in the tissues of reproductive organs in laying Japanese quail: an immunocytochemical study; Takata T et al.; The aim of this study was to determine whether Salmonella enteritidis (SE) inoculated into the peritoneal cavity would colonize tissues of reproductive organs in Japanese quail hens . Quail hens regularly laying were intraperitoneally inoculated with 5 x 10(7) or 5 x 10(8) SE cells, and the ovary, oviduct, kidney, spleen, liver, and large intestine were excised 24 or 48 h after the treatment . Paraffin sections of these organs were immunostained for SE . Invasion of SE was found in the tissues of the ovarian stroma, the follicular wall including superficial and theca layers, and occasionally in the granulosa layer and yolk . The SE immunoreaction product frequently was found in the fibroblast-like and macrophage-like cells in the stroma and surface layer of follicles . The SE immunoreaction products were identified on the mucosal surface, in the mucosal epithelium, and in the stromal tissues in all segments of the oviduct . Many of the bacteria were contained in the cytoplasm of mucosal epithelial cells and stromal cells in those tissues . The SE immunoreactions were also found in the tissues of kidney, spleen, and liver and in the large intestine . These results suggest that SE organisms introduced into the peritoneal cavity can invade and colonize the tissues of ovary and oviduct and may be responsible in the production of contaminated eggs. Vet Res Commun, 2003 May, 27(4), 257 - 73 Evaluation of treatment and prophylaxis with nitrofurans and comparison with alternative antimicrobial agents in experimental Salmonella enterica Serovar enteritidis infection in chicks; Chadfield MS et al.; The ability of the nitrofuran antimicrobial agents furazolidone and furaltadone to prevent, reduce or eliminate Salmonella enterica serovar enteritidis PT4 infection in artificially challenged day-old chicks was evaluated . Treating the birds with the nitrofurans failed to eliminate established infections with either furazolidone-resistant (FzR) or furazolidone-sensitive (FzS) strains . Simultaneous administration of the nitrofurans to day-old chicks challenged with FzS failed to prevent infection but reduced colonization significantly (p<0.05) compared to unmedicated controls . No reduction of colonization occurred with FzR . Challenging birds with FzS and simultaneous dosing with nitrofurans for 1 week, followed by a second week of continued treatment, resulted in an increase in the level of colonization in the second week rather than a decrease . Dosing with the nitrofurans (200 ppm) for 1 week prior to challenge with FzS and continued medication for a further week prevented colonization of the caecum, liver and spleen . However, cessation of dosing at the time of challenge with salmonella resulted in colonization . Chloramphenicol and tetracycline at concentrations of 200 ppm were both independently capable of preventing colonization by salmonella . Sulphadiazine initially reduced colonization but failed to eliminate the infection . Only when furazolidone was combined with chloramphenicol or when sulphadiazine was combined with trimethoprim, and the combined drugs were administered concurrently with the challenge, was colonization prevented. J Basic Microbiol, 2003, 43(4), 328 - 36 Multiplex PCR for the direct detection of Salmonella enterica from chicken, lamb and beef food products; Malkawi HI et al.; Three sets of known Salmonella enterica-specific primers were used collectively, for the first time, to evaluate the use of multiplex polymerase chain reaction (m-PCR) as a diagnostic tool to detect Salmonella enterica in naturally contaminated meat and poultry products . For this purpose a total of 300 samples representing the most frequently used fresh and frozen meat (beef and lamb) and poultry (chicken) products (whole, cut, ground, and processed) were collected from eight locations within Irbid city (Jordan) . After an enrichment step, DNA was extracted directly from each food sample and amplified using six Salmonella enterica specific primers . Samples were also analyzed using conventional microbiological methods for the confirmation of Salmonella enterica presence . Out of 300 samples, 93 samples were positive by m-PCR . On the other hand, 67 samples were positive by conventional microbiological methods and only 26 samples were positive by m-PCR alone.The primer pairs, used here, proved to be highly specific for Salmonella enterica . Using m-PCR, Salmonella enterica detection could be achieved easily and the results had been confirmed effortlessly within a short period of time (24-36 hours) compared to 3-8 days for the conventional microbiological methods . Our findings emphasize the value of using a combination of specific primer pairs instead of a single primer pair in the detection process to minimize any chance for any inherent experimental or natural error. J Food Prot, 2003 Jul, 66(7), 1253 - 9 Industry practices and compliance with U.S . Food and Drug Administration guidelines among California sprout firms; Thomas JL et al.; Since 1995, raw vegetable sprouts have been implicated as the vehicle of infection in 15 foodborne outbreaks involving Salmonella and 2 foodborne outbreaks involving Escherichia coli O157:H7 . To reduce the numbers of sprout-related outbreaks, the U.S . Food and Drug Administration (FDA) published Guidance for Industry: Reducing Microbial Food Safety Hazards for Sprouting Seeds in 1999 . Between October 2000 and April 2001, 61.5% (16 of 26) of the known commercial sprout firms in California were enrolled in a survey to evaluate the industry practices of California sprouting operations and to determine compliance with FDA guidelines . A standardized questionnaire was used to collect data on firm demographics and seed disinfection practices . Additionally, free chlorine levels in seed disinfection solutions were measured, and 48-h spent irrigation water samples were collected from each firm . The irrigation water was screened for Salmonella and E . coli O157:H7 with FDA-recommended test kits . Free chlorine levels in the treatment solutions ranged from 50 to 35,000 mg/liter (ppm), with a median of 14,000 mg/liter (ppm) . Free chlorine levels were higher for firms producing alfalfa sprouts than for those producing only mung bean or soybean sprouts (P=0.03) . Levels of free chlorine tended to be higher for firms using a calcium hypochlorite treatment solution than for firms using a sodium hypochlorite treatment solution (P=0.067) . All 32 irrigation water samples screened for Salmonella tested negative . Of the irrigation water samples tested for E . coil O157:H7, 75% (24 of 32) tested negative, and 25% (8 of 32) tested presumptive positive . The eight presumptive positive samples were found to be negative after further testing . These results indicate that producers of alfalfa sprouts are generally achieving the FDA-recommended calcium hypochlorite level of 20,000 mg/liter (ppm), whereas mung bean sprout producers are not. J Food Prot, 2003 Jul, 66(7), 1158 - 65 Reduction of Escherichia coli O157:H7 and Salmonella on laboratory-inoculated alfalfa seed with commercial citrus-related products; Fett WF et al.; Alfalfa sprouts contaminated with the bacterial pathogens Escherichia coli O157:H7 and Salmonella have been the source of numerous outbreaks of foodborne illness in the United States and in other countries . The seed used for sprouting appears to be the primary source of these pathogens . The aim of this study was to determine whether the efficacy of commercial citrus-related products for sanitizing sprouting seed is similar to that of high levels of chlorine . Five products (Citrex, Pangermex, Citricidal, Citrobio, and Environne) were tested at concentrations of up to 20,000 ppm in sterile tap water and compared with buffered chlorine (at 16,000 ppm) . Alfalfa seeds were inoculated with four-strain cocktails of Salmonella and E . coli O157:H7 to give final initial concentrations of ca . 9.0 and 7.0 CFU/g, respectively . Treatments (10 min) with Citrex, Pangermex, and Citricidal at 20,000 ppm and chlorine at 16,000 ppm produced similar log reductions for alfalfa seed inoculated with four-strain cocktails of E . coli O157:H7 and Salmonella (3.42 to 3.46 log CFU/g and 3.56 to 3.74 log CFU/g, respectively), and all four treatments were significantly (P<0.05) more effective than the control treatment (a buffer wash) . Citrobio at 20,000 ppm was as effective as the other three products and chlorine against Salmonella but not against E . coli O157:H7 . Environne was not more effective (producing reductions of 2.2 to 2.9 log CFU/g) than the control treatment (which produced reductions of 2.1 to 2.3 log CFU/g) against either pathogen . None of the treatments reduced seed germination . In vitro assays, as well as transmission electron microscopy, confirmed the antibacterial nature of the products that were effective against the two pathogens and indicated that they were bactericidal . When used at 20,000 ppm, the effective citrus-related products may be viable alternatives to chlorine for the sanitization of sprouting seed pending regulatory approval. J Food Prot, 2003 Jul, 66(7), 1154 - 7 Prevalence and antibiotic susceptibility of Salmonella isolated from foods in Korea from 1993 to 2001; Chung YH et al.; This study determined the prevalence of Salmonella in foods widely consumed in Korea from 1993 to 2001, along with antimicrobial susceptibility profiles of Salmonella isolates from these foods for 11 antibiotics . Overall, 41 Salmonella isolates, representing 15 serotypes, were obtained from 2.2% (29 of 1,334) of the samples examined, and most of the Salmonella isolates were recovered from broiler carcasses . The most common serotypes were Salmonella Enteritidis (29.3%), Salmonella Virginia (14.6%), and Salmonella Haart (12.2%) . All isolates were screened for antibiotic resistance; 14.6% of the isolates were susceptible to all of the antibiotics, 4.9% were resistant to one antimicrobial agent, 14.6% were resistant to two antimicrobial agents, 22.0% were resistant to three antimicrobial agents, 39.0% were resistant to four antimicrobial agents, and 4.9% were resistant to five antimicrobial agents . Most of the isolates showed resistance or intermediate resistance to streptomycin, ampicillin, carbenicillin, and/or tetracycline. J Food Prot, 2003 Jul, 66(7), 1139 - 45 Evaluation of the safety assurance level for Salmonella spp . throughout the food production chain in Switzerland; Sauli I et al.; In Switzerland . the safeguarding of food is the responsibility of industry, organizations, and governmental authorities . The dispersion of the tasks and the diversity of implemented safety measures among involved stakeholders do not allow a general overview of the national safety assurance level provided . A comprehensive evaluation of the level of safety assurance provided for foodborne pathogens such as Salmonella spp . is therefore lacking, and the prevalence of Salmonella spp . at various points in the food production chain is not known . The objectives of this study were to (i) collect data on safety measures implemented throughout the food production chain in Switzerland regarding Salmonella spp.; (ii) evaluate the safety assurance level for Salmonella spp . at each step of the production chain for chicken meat, pork, beef, and milk and dairy products (bovine origin); and (iii) gather data on the prevalence of the pathogen at each step . Data on implemented safety assurance measures for Salmonella spp . were gathered from the various stakeholders in the food production chain . The data were analyzed by a semiquantitative method that considered the quality and relevance of the implemented safety measures for Salmonella spp . The safety assurance level for Salmonella spp . was evaluated from "no safety assurance" to "very good safety assurance." Available results of testing for Salmonella spp . from 1998 to 2000 were used for calculating the prevalence of the pathogen throughout the food production chain . The results showed a varying safety assurance level for Salmonella spp . throughout the food production chain . Strengths (e.g., feed production for chickens) and weaknesses (e.g., pork production) were observed . These results serve as a basis for a rational optimization of the system. J Food Prot, 2003 Jul, 66(7), 1115 - 25 Tolerance to stress and ability of acid-adapted and non-acid-adapted Salmonella enterica serovar Typhimurium DT104 to invade and survive in mammalian cells in vitro; Fratamico PM; The ability of acid-adapted (AA) and non-acid-adapted (NA) Salmonella enterica serovar Typhimurium definitive type 104 (DT104) strains to invade and multiply in mammalian cells in vitro and to survive stress conditions was examined . DT104 and non-DT104 strains were grown in tryptic soy broth without glucose (NA) or in tryptic soy broth containing 1% glucose (AA) for 18 h at 37 degrees C . The invasiveness of DT104 strains in J774A.1 macrophage and Int407 intestinal cell lines was not more extensive than that of non-DT104 strains . In most cases, AA bacteria were less invasive than NA bacteria in both cell lines . Confocal microscopy showed that both DT104 and non-DT104 strains replicated in the two cell lines . In related studies, the survival levels of three strains of AA and NA DT104 and a non-DT104 (LT2) strain in 150 and 15 mM H2O2, 170 and 43 mM acetic acid, 2.6 M NaCl, 2.6 M NaCl containing 170 mM acetic acid, synthetic gastric fluid (SGF) at pH 2 and pH 3, and apple cider were compared . For all four strains, acid adaptation did not result in increased survival in apple cider . After 15 days of storage at 4 degrees C, reductions ranged from 1.96 to 4.1 log10 CFU/ml for AA bacteria and from 0.48 to 1.34 log10 CFU/ml for NA bacteria from a starting level of ca . 7.00 log10 CFU/ml of cider . Neither AA nor NA DT104 strains were more resistant to NaCl, acetic acid, H2O2, or SGF solutions than non-DT104 strain LT2 . The level of AA bacteria was not appreciably reduced after exposure to SGF; however, the level of NA bacteria decreased to nondetectable levels in SGF at pH 2 within 3 h of exposure . These results indicate that the DT104 strains examined were not more invasive, nor did they display increased survival in mammalian cells or increased resistance to food environment stresses compared with non-DT104 strains . However, acid adaptation resulted in increased resistance to a low-pH gastric environment for all strains tested . These data indicate that DT104 strains are likely not more virulent or resistant to stresses relevant to foods than are non-DT104 Salmonella and that procedures used to inactivate or inhibit the growth of Salmonella in foods are likely adequate for DT104 strains. Verh K Acad Geneeskd Belg, 2003, 65(3), 189 - 202 {Fertility and sterility in domestic animals}; de Kruif A; For most of the domestic animals the fertility rate is generally very good . If a uniparous female animal is served during the oestrus period by a male with good sperm quality, the pregnancy rate is 60 to 70% . Among the animals that deliver more than one offspring, in many cases the pregnancy rate even reaches more than 90% . Nevertheless, veterinarians are very frequently consulted for fertility problems in individual animals or in cattle or swine herds . The main causes of subfertility are: Insufficient sperm quality An inseminator with insufficient professional knowledge . The majority of the cows, horses and pigs are inseminated artificially (AI) . The insemination is not always carried out by experts . Not the right time for insemination . It especially occurs in animals with weak oestrus symptoms . Venereal infections . In earlier days these infections would occur very often . Due to the application of AI, most of these infections have been eradicated . The malfunctioning of the female genital system, which can be caused by various factors, such as cystic ovarian follicles, endometritis and anatomic abnormalities . The research on reproduction which has been going on during the past ten years in the department of Obstetrics, Reproduction and Herd Health, has been mainly concerned with: Embryo transplantation, in vitro fertilisation and ovum pick up The evaluation of sperm quality Improved freezing methods for both sperm and embryo's The development of new insemination techniques The composition of a new diluent for fresh sperm Cystic ovarian follicles in cows Subfertility in different species of animals Next to the above mentioned study fields, the department is also involved in the research into swine fever, respiratory diseases in pigs, antibiotic resistance in pigs and cattle, mastitis and metabolic problems in cattle and salmonella infections in pigs. Eur J Biochem, 2003 Aug, 270(15), 3271 - 9 Physicochemical characterization and biological activity of a glycoglycerolipid from Mycoplasma fermentans; Brandenburg K et al.; We report a comprehensive physicochemical characterization of a glycoglycerolipid from Mycoplasma fermentans, MfGl-II, in relation to its bioactivity and compared this with the respective behaviors of phosphatidylcholine (PC) and a bacterial glycolipid, lipopolysaccharide (LPS) from deep rough mutant Salmonella minnesota strain R595 . The beta left arrow over right arrow alpha gel-to-liquid crystalline phase transition behavior of the hydrocarbon chains with Tc = 30 degrees C for MfGl-II as well as for LPS exhibits high similarity between the two glycolipids . A lipopolysaccharide-binding protein (LBP)-mediated incorporation into negatively charged liposomes is observed for both glycolipids . The determination of the supramolecular aggregate structure confirms the existence of a mixed unilamellar/cubic structure for MfGl-II, similar to that observed for the lipid A moiety of LPS . The biological data clearly show that MfGl-II is able to induce cytokines such as tumor necrosis factor-alpha (TNF-alpha) in human mononuclear cells, although to a significantly lower degree than LPS . In contrast, in the Limulus amebocyte lysate test, MfGl-II is completely inactive, and in the CHO reporter cell line it does not indicate any reactivity with the Toll-like receptors TLR-2 and -4, in contrast to control lipopeptides and LPS . These data confirm the applicability of our conformational concept of endotoxicity to nonlipid A structures: an amphiphilic molecule with a nonlamellar cubic aggregate structure corresponding to a conical conformation of the single molecules and a sufficiently high negative charge density in the backbone. Int J Med Microbiol, 2003 Jun, 293(2-3), 219 - 23 Molecular epidemiology of ampicillin-resistant clinical isolates of Salmonella enterica serovar Typhimurium; Biendo M et al.; Thirty-nine multiresistant Salmonella enterica serovar Typhimurium (S . Typhimurium) isolates were obtained from 33 children and 6 adults hospitalized from 1996 to 1999 in the University Hospital of Amiens (France) . S . Typhimurium was cultured from stools (n=36), blood samples (n=2) and peritoneal fluid (n=1) . These isolates were characterized by biotyping, antibiotic susceptibility test, RAPD-PCR, and PFGE typing . Emergence of pentaresistant S . Typhimurium isolates (phenotype ACSSuTe) was observed, and five of them were resistant to nalidixic acid and of intermediate susceptibility to pefloxacin . Genotypic analysis of both RAPD and PFGE results showed that there were 7 different patterns . Thirty-three isolates gave an identical pattern (AI) and were considered as epidemic isolates; the six remaining patterns (each containing one isolate) corresponded to sporadic cases . Antibiotic susceptibility patterns, RAPD and PFGE patterns subdivided the 39 isolates into 9 clonally related groups . One of them (pattern AI and R-pattern a) was implicated in 74% of the cases. J Bacteriol, 2003 Aug, 185(15), 4508 - 18 Lateral flagellar gene system of Vibrio parahaemolyticus; Stewart BJ et al.; Vibrio parahaemolyticus possesses dual flagellar systems adapted for movement under different circumstances . A single polar flagellum propels the bacterium in liquid (i.e., swimming) with a motor that is powered by the sodium motive force . Multiple proton-driven lateral flagella enable translocation over surfaces (i.e., swarming) . The polar flagellum is produced continuously, while production of lateral flagella is induced when the organism is grown on surfaces . This work describes the isolation of mutants with insertions in the structural and regulatory laf genes . A Tn5-based lux transcriptional reporter transposon was constructed and used for mutagenesis and subsequent transcriptional analysis of the laf regulon . Twenty-nine independent insertions were distributed within 16 laf genes . DNA sequence analysis identified 38 laf genes in two loci . Among the mutants isolated, 11 contained surface-induced lux fusions . A hierarchy of laf gene expression was established following characterization of the laf::lux transcriptional fusion strains and by mutational and primer extension analyses of the laf regulon . The laf system is like many enteric systems in that it is a proton-driven, peritrichous flagellar system; however, laf regulation was different from the Salmonella-Escherichia coli paradigm . There is no apparent flhDC counterpart that encodes master regulators known to control flagellar biosynthesis and swarming in many enteric bacteria . A potential sigma(54)-dependent regulator, LafK, was demonstrated to control expression of early genes, and a lateral-specific sigma(28) factor controls late flagellar gene expression . Another notable feature was the discovery of a gene encoding a MotY-like product, which previously had been associated only with the architecture of sodium-type polar flagellar motors. Chemosphere, 2003 Sep, 52(9), 1641 - 6 The mutagenic potentials of tap water samples in Shanghai; Shen L et al.; The tap water samples were collected from the users' ends in several areas of Shanghai, which is located in Taihu Lake basin, Eastern China . Source water samples were also collected from two municipal source water facilities at the same time . Samples were assayed by three different short-term mutagenicity test systems: Salmonella/microsome assay (Ames test), the Arabinose resistance test (Ara test) and the SOS/umu test . The data showed that two source water samples did not display direct mutagenic potentials . Two tap water samples from city north, which were directly from Yangtze River, were also not mutagenic . Water samples from city south and middle which used source water originating from Taihu Lake were proved to be contaminated with mutagenic potentials by three different assay techniques . The boiled water displayed an even stronger mutagenic potential compared to its original tap water . The molecular mechanism of mutagenicity was associated with a reading frame-shifting potential . GC-MS analysis of tap water extracts from city middle and corresponding source water was compared . Qualitatively similar spectra were observed except for the peaks of three chlorinated aromatic hydrocarbon compounds, which existed only in the tap water . Since the water source has been polluted, raw water was heavily chlorinated in order to sterilize . More toxic compounds, including mutagens, might form during the multi-chlorination . Caution about the possibility of elevated cancer risks in the population that consumes heavily chlorinated water should be kept in mind . A cohort study in the residents of Shanghai is required. Indian J Med Res, 2003 Jan, 117, 10 - 2 An unusually high occurrence of Salmonella enterica serotype paratyphi A in patients with enteric fever; Tankhiwale SS et al.; BACKGROUND & OBJECTIVES: Salmonella enterica serotype Paratyphi A has been reported less frequently as a causative agent of enteric fever . Reports on the antimicrobial susceptibility of this pathogen are few and varied . An unusually high occurrence of S . Paratyphi A was noted in a tertiary care hospital at Nagpur, Maharashtra during April 2001-September 2002 . An effort was made to study the antimicrobial susceptibility pattern and phage types of the isolates . METHODS: Blood cultures of patients suspected to have enteric fever admitted to the Indira Gandhi Medical College and Hospital, Nagpur were processed by conventional methods . Antimicrobial susceptibility was tested by Kirby-Bauer disc diffusion method and the minimum inhibitory concentration (MIC) to chloramphenicol was determined . RESULTS: Eighteen (46.15%) of 39 Salmonella isolates were S . Paratyphi A and all were sensitive to ciprofloxacin and cephotaxime . Twelve (66.67%) strains were sensitive to ampicillin and 13 (72.22 %) to chloramphenicol . Two strains (11.11%) were resistant to three drugs (ampicillin, chloramphenicol and cotrimoxazole) simultaneously . The prevalent phage type in the local population was phage type I . INTERPRETATION & CONCLUSION: The high occurrence of S . Paratyphi A found in the present study indicated the emergence of this rare pathogen of enteric fever in the local population . Though some degree of resistance was encountered with ampicillin and chloramphenicol, all the isolates were sensitive to ciprofloxacin, currently a drug of choice for enteric fever . Multidrug resistance was rare. Curr Gastroenterol Rep, 2003 Aug, 5(4), 279 - 86 Current trends in typhoid Fever; Crum NF; Typhoid fever, a systemic infection caused by Salmonella enterica serotype typhi, remains an important worldwide cause of morbidity and mortality . Endemic cases in the United States are unusual, with most following foreign travel to the Indian subcontinent, Africa, Asia, or Latin America . The classic findings of typhoid fever include rose spots, relative bradycardia, and stepwise fevers, but unfortunately these signs are frequently absent . Gastrointestinal manifestations may include diffuse abdominal pain, bleeding, perforation, cholecystitis, and cholangitis . The diagnosis should be suspected after collection of the appropriate clinical and travel history with confirmation by blood or bone marrow culture . Novel methods are in development to establish the diagnosis when cultures are negative or unavailable . Multidrug resistance has increased worldwide, and decisions on antimicrobial therapy must take such resistance into account . The empiric treatment of choice is a fluoroquinolone drug; ceftriaxone and azithromycin are alternatives . Preventive strategies include good sanitation and food handling practices along with vaccination of selected groups. Mol Microbiol, 2003 Aug, 49(3), 685 - 704 Salmonella type III effectors PipB and PipB2 are targeted to detergent-resistant microdomains on internal host cell membranes; Knodler LA et al.; The intracellular pathogen, Salmonella enterica, translocates type III effectors across its vacuolar membrane into host cells . Herein we describe a new Salmonella effector, PipB2, which has sequence similarity to another type III effector, PipB . In phagocytic cells, PipB2 localizes to the Salmonella-containing vacuole (SCV) and tubular extensions from the SCV, Salmonella-induced filaments (Sifs) . We used the specific targeting of PipB2 in macrophages to characterize Sifs in phagocytic cells for the first time . In epithelial cells, PipB2 has a unique localization pattern, localizing to SCVs and Sifs and additionally to vesicles at the periphery of infected cells . We further show that the N-terminal 225-amino-acid residues of PipB2 are sufficient for type III translocation and association with SCVs and Sifs, but not peripheral vesicles . Subcellular fractionation demonstrated that both PipB and PipB2 associate with host cell membranes and resist extraction by high salt, high pH and to a significant extent, non-ionic detergent . Furthermore, PipB and PipB2 are enriched in detergent-resistant microdomains (DRMs), also known as lipid rafts, present on membranes of SCVs and Sifs . The enrichment of Salmonella effectors in DRMs on these intracellular membranes probably permits specific interactions with host cell molecules that are concentrated in these signalling platforms. Cell Microbiol, 2003 Aug, 5(8), 501 - 11 Functions and effectors of the Salmonella pathogenicity island 2 type III secretion system; Waterman SR et al.; Salmonella enterica uses two functionally distinct type III secretion systems encoded on the pathogenicity islands SPI-1 and SPI-2 to transfer effector proteins into host cells . A major function of the SPI-1 secretion system is to enable bacterial invasion of epithelial cells and the principal role of SPI-2 is to facilitate the replication of intracellular bacteria within membrane-bound Salmonella-containing vacuoles (SCVs) . Studies of mutant bacteria defective for SPI-2-dependent secretion have revealed a variety of functions that can be attributed to this secretion system . These include an inhibition of various aspects of endocytic trafficking, an avoidance of NADPH oxidase-dependent killing, the induction of a delayed apoptosis-like host cell death, the control of SCV membrane dynamics, the assembly of a meshwork of F-actin around the SCV, an accumulation of cholesterol around the SCV and interference with the localization of inducible nitric oxide synthase to the SCV . Several effector proteins that are translocated across the vacuolar membrane in a SPI-2-dependent manner have now been identified . These are encoded both within and outside SPI-2 . The characteristics of these effectors, and their relationship to the physiological functions listed above, are the subject of this review . The emerging picture is of a multifunctional system, whose activities are explained in part by effectors that control interactions between the SCV and intracellular membrane compartments. Microb Pathog, 2003 Jul, 35(1), 43 - 8 Intracellular expression of the Salmonella plasmid virulence protein, SpvB, causes apoptotic cell death in eukaryotic cells; Kurita A et al.; The spv genes carried on the Salmonella virulence plasmid are commonly associated with severe systemic infection in experimental animals . The SpvB virulence-associated protein has been shown to ADP-ribosylate actin, and this enzymatic activity is essential for virulence in mice . Here, we present evidence that intracellular expression of SpvB protein induces not only disruption of actin filaments but also apoptotic cell death in eukaryotic cells. J Interferon Cytokine Res, 2003 Jun, 23(6), 319 - 27 Differential regulation of cytokine gene expression by avian heterophils during receptor-mediated phagocytosis of opsonized and nonopsonized Salmonella enteritidis; Kogut MH et al.; Internalization of pathogens by phagocytic cells triggers the innate immune response, which in turn regulates the acquired response . Phagocytes express a variety of receptors that are involved in recognition of pathogens, including (1) pattern recognition receptors (PRR), which recognize conserved motifs, (2) complement receptors (CR), which recognize complement-opsonized pathogens, and (3) Fc receptors (FcR), which recognize antibody-opsonized pathogens . Recognition of microbes is accompanied by the induction of multiple cell processes, including the production of proinflammatory and anti-inflammatory cytokines and chemokines . The objective of the present experiments was to use probes to known avian proinflammatory and anti-inflammatory cytokines and TaqMan technology to ascertain levels of cytokine gene expression in avian heterophils following receptor-mediated phagocytosis of either nonopsonized Salmonella enteritidis (SE), serum-opsonized SE, or IgG-opsonized SE . Expression of interleukin-6 (IL-6) and IL-8, considered in mammals as a proinflammatory chemokine, were upregulated following exposure to the nonopsonized or the opsonized SE . However, mRNA expression for IL-18 and interferon-gamma (IFN-gamma) was downregulated, and the expression of mRNA for the anti-inflammatory cytokine transforming growth factor-beta4 (TGF-beta 4) was upregulated . Interestingly, IL-1beta mRNA expression was significantly upregulated in heterophils that phagocytized either the nonopsonized SE via PRRs or IgG-opsonized SE via FcRs, whereas serum-opsonized SE phagocytized by CRs induced a downregulation of IL-1beta mRNA . These results suggest that signaling interactions initiated by receptor recognition of the microbe surface differentially regulate the induction of inflammatory cytokines in avian heterophils. J Virol, 2003 Aug, 77(15), 8249 - 55 Vaccination of mice with bacteria carrying a cloned herpesvirus genome reconstituted in vivo; Cicin-Sain L et al.; Bacterial delivery systems are gaining increasing interest as potential vaccination vectors to deliver either proteins or nucleic acids for gene expression in the recipient . Bacterial delivery systems for gene expression in vivo usually contain small multicopy plasmids . We have shown before that bacteria containing a herpesvirus bacterial artificial chromosome (BAC) can reconstitute the virus replication cycle after cocultivation with fibroblasts in vitro . In this study we addressed the question of whether bacteria containing a single plasmid with a complete viral genome can also reconstitute the viral replication process in vivo . We used a natural mouse pathogen, the murine cytomegalovirus (MCMV), whose genome has previously been cloned as a BAC in Escherichia coli . In this study, we tested a new application for BAC-cloned herpesvirus genomes . We show that the MCMV BAC can be stably maintained in certain strains of Salmonella enterica serovar Typhimurium as well and that both serovar Typhimurium and E . coli harboring the single-copy MCMV BAC can reconstitute a virus infection upon injection into mice . By this procedure, a productive virus infection is regenerated only in immunocompromised mice . Virus reconstitution in vivo causes elevated titers of specific anti-MCMV antibodies, protection against lethal MCMV challenge, and strong expression of additional genes introduced into the viral genome . Thus, the reconstitution of infectious virus from live attenuated bacteria presents a novel concept for multivalent virus vaccines launched from bacterial vectors. Arch Toxicol, 2003 Aug, 77(8), 477 - 84 Epub 2003 Jul 11. Effect of chrysin, a flavonoid compound, on the mutagenic activity of 2-amino-1-methyl-6-phenylimidazo{4,5- b}pyridine (PhIP) and benzo(a)pyrene (B(a)P) in bacterial and human hepatoma (HepG2) cells; Uhl M et al.; The aim of the present study was to investigate the antimutagenic effects of chrysin (CR), a flavonoid compound contained in many fruits, vegetables and honey . Earlier investigations with bacterial indicators showed that CR is one of the most potent antimutagens among the flavonoids . In the present study, we tested the compound in the Salmonella strains TA98 and TA100 in combination with benzo(a)pyrene (B(a)P) and 2-amino-1-methyl-6-phenylimidazo{4,5- b}pyridine (PhIP) and found pronounced protective activity over a concentration range between 10 and 100 microg/ml . The compound itself was devoid of mutagenic activity at all concentrations tested . In the micronucleus (MN) assay with human-derived HepG2 cells, a different pattern of activity was seen . CR itself caused significant induction of MN at dose levels > or =15 microg/ml; in combination experiments with B(a)P and PhIP, U-shaped dose-response curves were obtained and protection was found only in a narrow dose range (5 - 10 microg/ml) . Our findings indicate that the molecular mechanisms that account for the antimutagenic effects of CR in bacterial cells are different from those responsible for the effects in HepG2 cells . Earlier reports indicate that the antimutagenic effects of CR towards B(a)P and heterocyclic amines in bacterial indicators is due to inhibition of the activity of CYP1A . In contrast to this, we found a significant induction of CYP1A1 activity in HepG2 cells by CR . It can also be excluded that induction of GST, which is involved in the detoxification of polycyclic aromatic hydrocarbons accounts for the protective effects of CR against B(a)P since this enzyme was not significantly induced in the HepG2 cells . In the case of PhIP, induction of UDGPT and/or inhibition of sulfotransferase seen in human derived HepG2 cells after exposure to CR might play a role in the antimutagenic effects . In conclusion, our findings show that data from antimutagenicity studies with bacterial indicators cannot be extrapolated to HepG2 cells, and that CR causes genotoxic effects at higher dose levels in the latter cells . The implications of these observations for human chemoprevention strategies are discussed. Am J Reprod Immunol, 2003 May, 49(5), 297 - 307 MD-1 is a critical part of the mechanism causing Th1-cytokine-triggered murine fetal loss syndrome; Clark DA et al.; PROBLEM: Fetal loss syndrome (abortion/resorption) occurring on or after gestation day (gd) 9.5 in CBA/JxDBA/2 matings is dependent upon presence of TNF-alpha + IFN-gamma, which act by increasing expression of fg12 prothrombinase at the feto-maternal interface . The magnitude by which the abortion rate can be boosted by an injection of these cytokines on gd 7.5 depends on endogenous rate of loss, and appears to depend on microbial flora . Is cytokine-triggered abortion dependent upon a third signaling pathway that senses 'danger'? METHODS: Female CBA/J were mated to DBA/2 males and, C57B1/6 and C57B1/6 TNFalphaR1-/-Mak were mated to C57B1/6 control or TNFalphaR1-/-Mak males . LPS from Escherichia coli and Salmonella enteritidis, or the combination of TNF-alpha + IFN-gamma, was injected to stimulate abortions . The effect of anti-MD-1, which interferes with expression of CD14 and, hence, with signaling by LPS via the CD14-tlr4 complex, on TNF-alpha + IFN-gamma was tested . The presence of MD-1 in the uterus was evaluated by in situ hybridization, and effect of lipopolysaccharide (LPS) on mice lacking TNF-alphaR1 was tested . RESULTS: Anti-MD-1 completely abrogated TNF-alpha + IFN-gamma-induced abortions . MD-1 was expressed on trophoblast and in deciduas on gd 8.5 but LPS could not abort mice that lacked the type 1 receptor for TNF-alpha . Pregnant CBA/J females had classical resorptions (abortions) countable on gd 13.5-14.5 in response to LPS from E . coli or S . enteritidis, but C57B1/6 strain mice resorbed only in response to the latter, and E . coli LPS appeared to induce 'occult' losses . 'Occult' loss did not require TNF-alphaR1 . CONCLUSIONS: TNF-alpha + IFN-gamma could not induce murine abortions without co-presence of a 'danger' signal such as LPS acting via CD14 on toll receptors, and LPS could not act without co-signaling by TNF-alpha . Classical resorptions/abortions and 'occult' losses have a different mechanism in these models as reflected in type of endotoxin and requirement for TNF-alphaR1 signaling. Ugeskr Laeger, 2003 Jun 16, 165(25), 2577 - 8 {Salmonella infection complicated with acute renal failure}; Thogersen T et al.; Acute renal failure is a known complication to Salmonella gastroenteritis, and patients with chronic renal failure or impaired host defence are at increased risk . In the two presented cases there had been a few days of gastroenteritis before the hospitalisation, but the only symptoms at the admission were fatigue and dyspnoea . In both cases severe uraemia had developed and the patients and their physicians did not expect the episode of gastroenteritis to be the only etiology of acute renal failure . Both patients had normal renal histology and Salmonella was grown in their faeces . Subsequently, their renal function was normalised . In these patients dialysis and renal biopsies would have been unnecessary if the ability of even a moderate Salmonella infection to cause acute renal failure in a healthy subject had been realised and prompt rehydration had been initiated. J Infect Dis, 2003 Jul 15, 188(2), 202 - 8 Epub 2003 Jun 20. Epidemiology of bloodstream infections in a bacille Calmette-Guérin-vaccinated pediatric population in Malawi; Archibald LK et al.; The risk of Mycobacterium bovis bloodstream infection (BSI) in bacille Calmette-Guerin (BCG)-vaccinated children with human immunodeficiency virus (HIV) infection remains uncharacterized . We studied pediatric inpatients during the 1998 dry season in Malawi . After a detailed clinical evaluation, blood was drawn for culture and HIV testing . Of 229 children, 128 (56%) were male, 35 (15.3%) had BSI, and 30% of children aged >1.5 years (median, 2.7 years; range, 1 month-13 years) had HIV infection . The predominant pathogen was non-typhi Salmonella; neither Mycobacterium tuberculosis nor M . bovis was isolated . A diagnosis of malnutrition or sepsis was predictive of BSI; malnutrition alone correlated with both death and BSI . The bloodstream dissemination of M . tuberculosis and M . bovis BCG is uncommon in HIV-infected children vaccinated with BCG . Correlates such as malnutrition or sepsis can provide algorithms for identifying children who need observation or empirical antimicrobial therapy for BSI in the absence of appropriate laboratory testing. Clin Diagn Lab Immunol, 2003 Jul, 10(4), 670 - 9 Immune responses against Salmonella enterica serovar enteritidis infection in virally immunosuppressed chickens; Sheela RR et al.; To understand the role of immune mechanisms in protecting chickens from Salmonella infections, we examined the immune responses of Salmonella enterica serovar Enteritidis-infected chickens and the effect of chicken anemia virus (CAV), a T-cell-targeted virus, on S . enterica serovar Enteritidis-induced immune responses . One-day-old chicks were orally inoculated with S . enterica serovar Enteritidis with or without intramuscular injection of CAV . The bacterial infection, pathology, and immune responses of chickens were evaluated at 14, 28, and 56 days postinoculation . The infection increased the levels of S . enterica serovar Enteritidis-specific mucosal immunoglobulin A (IgA), the number of gut-associated T cells, and the titer of serum IgG specific for S . enterica serovar Enteritidis surface antigens . CAV infection depressed these immune responses, especially the mucosal immune responses, but did not increase the number of S . enterica serovar Enteritidis-infected cells in the intestine . The severity of pathological lesions appeared to be reciprocal to the level of immune responses, but the S . enterica serovar Enteritidis infection persisted . These results suggest that oral infection of S . enterica serovar Enteritidis in chickens induces both mucosal and systemic immune responses, which have a limited effect on the S . enterica serovar Enteritidis infection under conditions designed to mimic the field situation. Clin Diagn Lab Immunol, 2003 Jul, 10(4), 546 - 51 Adrenomedullin expression by gastric epithelial cells in response to infection; Allaker RP et al.; Many surface epithelial cells express adrenomedullin, a multifunctional peptide found in a wide number of body and cell systems . Recently, we and others have proposed that adrenomedullin has an important novel role in host defense . This peptide has many properties in common with other cationic antimicrobial peptides, including the human beta-defensins . Upon exposure of human gastric epithelial cells to viable cells of invasive or noninvasive strains of Helicobacter pylori, Escherichia coli, Salmonella enterica, or Streptococcus bovis, a significant increase in adrenomedullin secretion from these cells was demonstrated . Adrenomedullin gene expression was also increased in response to these microorganisms . Similar observations were noted when these cells were incubated with proinflammatory cytokines such as interleukin 1 alpha (IL-1 alpha), IL-6, tumor necrosis factor alpha and lipopolysaccharide . In cultured cells and an animal infection model, increased adrenomedullin peptide and gene expression was demonstrated when exposed to E . coli or Mycobacterium paratuberculosis, respectively . The data suggest there is a strong association between epithelial infection, inflammation, and adrenomedullin expression, which may have clinical relevance . The regulation of adrenomedullin expression may have therapeutic applications, such as improving or enhancing mucosal immunity. J Toxicol Environ Health A, 2003 Jul 25, 66(14), 1351 - 70 A comparison of two methods for fractionating complex mixtures in preparation for toxicity analysis; Cizmas L et al.; Chemical fractionation is a widely used tool for the chemical and toxicological characterization of complex mixtures . The objective of this research was to compare two frequently employed methods for fractionating a wood preserving waste (WPW) containing polycyclic aromatic hydrocarbons (PAHs) and pentachlorophenol (PCP) . The first method involved fractionation of the WPW into acid, base, and neutral fractions using a liquid-liquid acid/base/neutral (A/B/N) technique . The second method utilized alumina column chromatography to produce two fractions, A1 and A2 . Gas chromatography and mass spectrometry were used to quantify the chemical components in all fractions . The alumina method recovered 473,338 mg of total PAHs (tPAHs) per kilogram crude, while the A/B/N method yielded only 193,379 mg tPAHs/kg crude . In contrast, the A/B/N method recovered 13.7 mg PCP/kg crude while the alumina method yielded only 0.5 mg PCP/kg crude . Three bioassays were used to determine the toxicity of the crude extract and fractions . The neutral and A1 fractions contained the highest levels of tPAHs and benzo{a}pyrene (BaP) but failed to induce a positive response in the Salmonella/microsome assay with concentrations containing as much as 1800 and 2500 ng BaP/plate, respectively . In the Escherichia coli prophage induction assay, the acid fraction, which contained 472 mg PCP/kg fraction, induced a positive response, as did the base fraction, which did not contain detectable PCP . Significant reduction of gap junctional intercellular communication in hepatic cells occurred with the crude extract and acid, base, and neutral fractions . Overall, the results of these bioassays suggest that PCP genotoxicity was expressed in the acid fraction, whereas the cumulative genotoxicity of genotoxic PAHs appeared to be masked in the isolates from either fractionation method . The optimal fractionation method for a mixture of chlorophenols and PAHs may involve a refined hybrid method. Avian Pathol, 2003 Jun, 32(3), 225 - 37 Investigation of the distribution and control of Salmonella enterica serovar Enteritidis PT6 in layer breeding and egg production; Davies R et al.; Investigations were carried out in a layer breeder hatchery, a layer parent rearing farm, a layer parent farm and in a commercial pullet rearing and cage layer farm where Salmonella enterica serovar Enteritidis (S . Enteritidis) PT6 had become established . PT6 was initially found in focal points in the hatchery, such as hatcher ventilation ducting, tray wash areas and waste areas, but improved disinfection was followed by a rapid disappearance of contamination . Several different phage types of S . Enteritidis were found in the hatchery but most of these proved to be genotypically identical with PT6 . Investigations of contaminated layer breeder and rearing sites showed that the terminal disinfection programmes in place were effective in that no carry-over of infection occurred and the organism was rapidly eliminated from the organization . Infection with PT6 originating from chicks was investigated on a commercial pullet rearing farm . After several rounds of treatment with a fluoroquinolone antibiotic and competitive exclusion, no Salmonella was found in faeces or cloacal swabs but was present in dust in one of six houses . Sampling carried out after cleaning and disinfection confirmed clearance of the organism from the site, but infection did become established in a commercial laying house receiving the birds. J Infect, 2003 Jul, 47(1), 33 - 9 Comparison of phenotypic and genotypic characteristics of Salmonella bredeney associated with a poultry-related outbreak of gastroenteritis in Northern Ireland; Moore JE et al.; OBJECTIVES . To employ a combination of phenotypic and genotypic subspecies typing methods to aid in an epidemiological investigation of an outbreak of Salmonella bredeney involving ten persons . METHODS . Isolates were characterised by employing antibiogram typing, in addition to two genotyping techniques, including pulsed field gel electrophoresis (PFGE), random amplification of polymorphic DNA (RAPD) with two oligonucleotide primers . RESULTS . An outbreak of gastroenteritis associated with S . bredeney (serovar O:4 H:Lv 1,7) occurred in Belfast, Northern Ireland in November 1997 . In total, ten cases were confirmed, of which eight had consumed chicken cooked at local butchers and retailed through one of two local bakeries . One of the remaining cases was secondarily infected within her home and the final case had eaten a product other than cooked chicken from one of the bakeries . Food preparation practices were inadequate in one of the bakeries in question and record keeping and possibly cooking procedures were inadequate in the butchers . S . bredeney was isolated from an uncooked chicken supplied to the butchers confirming that improperly cooked chicken was most likely the source of the outbreak . All outbreak clinical isolates were indistinguishable from each other and were similar to the isolate obtained from the uncooked poultry demonstrating that these DNA-based methods were valuable in the molecular characterization of S . bredeney . CONCLUSIONS . This report emphasises the importance and maintenance of an effective hazard analysis critical control point (HACCP) approach to the processing and retailing of foodstuffs containing chicken in order to help eliminate hazards to public health. Toxicol In Vitro, 2003 Aug, 17(4), 403 - 12 Mutagenicity of bitumen and asphalt fumes; Heikkila PR et al.; The mutagenicity of asphalt fumes was tested with the Salmonella bioassays . The aim was to investigate if recycled additives modify the genotoxicity of emissions . Recycling of old asphalt is increasing, and we studied also the mutagenicity of emissions sampled during the re-use of asphalt . The composition of vapours and fumes were analysed by gas chromatography and by liquid chromatography . Bitumens containing coal fly ash (CFA) or waste plastics were heated to the paving temperatures in the laboratory . In the field, bitumen fumes were collected during paving of stone mastic asphalts (lime or CFA as a filler), remixing of stone mastic asphalt (lime or CFA as a filler), and of asphalt concrete . All the lab-generated vapour fractions were non-mutagenic . The particulate fractions were mutagenic with TA98 in the presence of the S9 activation . In addition, the lab-fumes from bitumen containing waste plastics were positive with both strains without S9 . Only particulate fractions sampled in the field were tested . They were mutagenic with and without metabolic activation with both strains . The mutagenic potency of the field samples was higher than that of the lab-generated fumes without S9, and the remixing fumes were more mutagenic than the normal paving and lab-generated fumes with S9 . The use of inorganic additive, CFA, did not change the mutagenicity of the fumes, whereas the organic additive, waste plastics, increased the mutagenicity of the laboratory emissions significantly. Toxicol Lett, 2003 Aug 28, 143(3), 291 - 9 Inhibition of aflatoxin B1 mutagenicity by cyclopiazonic acid in the presence of human liver preparations; Sabater Vilar M et al.; Co-occurrence of cyclopiazonic acid (CPA) and aflatoxin B(1) (AFB(1)) has been reported in different food commodities . Recently, we have shown that CPA reduces AFB(1) mutagenicity in the standard Salmonella-Microsome-Assay using rat S9-mix for metabolic activation (Environ . Toxicol . Pharmacol . 11 (2002) 207) . When using S9-mix prepared from individual liver fractions of human patients, CPA was found to be non-mutagenic, but exerted a significant reduction of the mutagenicity of AFB(1) . Moreover, CPA was shown to inhibit testosterone hydroxylation, but not methoxyresorufin dealkylation (MROD), in human S9 . Thus, the reduction of the AFB(1) mutagenicity by CPA may be attributed to the inhibitory effect of CPA on cytochrome P450 (CYP450) 3A4 activity . These findings might be of relevance to the epidemiology of food-borne mycotoxicosis as similar molar ratios to those investigated here have been reported in food commodities. MMWR Morb Mortal Wkly Rep, 2003 Jul 4, 52(26), 613 - 5 Multistate outbreak of Salmonella serotype typhimurium infections associated with drinking unpasteurized milk--Illinois, Indiana, Ohio, and Tennessee, 2002-2003; Effects of carrageenans on the binding et al.; Division of Microbiology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, JapanThe effects of carrageenans (CGNs) on the host defense mechanisms of macrophages against Salmonella infection were examined in vitro by using macrophage-like J774.1 cells . Iota-CGN reduced the Salmonella-binding and phagocytotic activities of J774.1 cells, but it increased the killing activity of the cells . Kappa-CGN increased the binding activity, but reduced the killing ability . CGNs would affect the host defense mechanisms by modulating the macrophage functions. J Clin Microbiol, 2003 Jul, 41(7), 3229 - 32 Comparison of Salmonella chromogenic medium with DCLS agar for isolation of Salmonella species from stool specimens; Cassar R et al.; Salmonella chromogenic medium (SCM; Oxoid, Basingstoke, United Kingdom), a new selective chromogenic medium, was compared to DCLS agar (Oxoid) for the detection and presumptive identification of Salmonella species from stool samples . This medium contains two chromogenic substrates, Magenta-cap (5-bromo-6-chloro-3-indolylcaprylate), which is hydrolyzed by Salmonella species to give magenta colonies, and X-Gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside), which is incorporated to visualize beta-D-galactosidase-producing organisms as blue colonies . Thus, non-Salmonella organisms appear blue or are not stained by any of the chromogens of the medium . A total of 500 stool samples were investigated by plating them directly and after selenite enrichment on DCLS agar and SCM . A total of 44 Salmonella-positive stool samples were detected . The sensitivities for direct plating and after enrichment were 22.7 and 81.8%, respectively, for DCLS agar, and for SCM these values were 34.1 and 100%, respectively . The specificities for direct plating and after enrichment were 82.5 and 72.8%, respectively, for DCLS agar and 98.5 and 95.8%, respectively, for SCM . According to these results, the sensitivities of SCM and DCLS agar were comparable on primary plating . However, the sensitivity of SCM was significantly higher after enrichment . In addition, the specificity of SCM was also significantly higher than that of DCLS agar both before and after enrichment . On the basis of these results, SCM can be recommended for the isolation of Salmonella species from stool samples in preference to DCLS agar. J Microbiol Methods, 2003 Sep, 54(3), 381 - 90 A rapid and direct real time PCR-based method for identification of Salmonella spp; Rodriguez-Lazaro D et al.; The aim of this work was the validation of a rapid, real-time PCR assay based on TaqMan technology for the unequivocal identification of Salmonella spp . to be used directly on an agar-grown colony . A real-time PCR system targeting at the Salmonella spp . invA gene was optimized and validated through a four times repeated blind experiment performed in two different laboratories including 50 Salmonella spp . with representative strains from each of the 5 different Salmonella subgenera and 30 non-Salmonella strains . Both parameters DeltaR(n) (fluorescence intensity of template through a normalized reporter value) and C(T) (cycle at which the fluorescence intensity achieved a pre-established threshold) were analyzed . Overall mean DeltaR(n) and C(T) values for Salmonella strains (2.14+/-0.87 and 15.30+/-0.90, respectively) were statistically different from values for non-Salmonella strains, allowing the establishment of cut-off DeltaR(n) and C(T) values based on 95% confidence intervals that allowed the correct identification of all strains tested in each independent experiment . The accuracy of this assay in terms of inclusivity and exclusivity was 100% . Moreover, the PCR system proved to be especially convenient because the pre-mix containing all PCR reagents except for the bacterial cells could be kept at -20 degrees C for at least 1 month before its use . The optimized TaqMan real-time PCR assay is a useful, simple and rapid method for routine identification of Salmonella spp., irrespective of the particular subgenus. Appl Environ Microbiol, 2003 Jul, 69(7), 4312 - 5 Nontyphoidal salmonellae in United Kingdom badgers: prevalence and spatial distribution; Wilson JS et al.; Eighteen (72%) of 25 badger social groups were found to excrete Salmonella enterica serovar Ried, S . enterica serovar Binza, S . enterica serovar Agama, or S . enterica serovar Lomita . Each serovar was susceptible to a panel of antimicrobials . Based on results of pulsed-field gel electrophoresis, the S . enterica serovar Agama and S . enterica serovar Binza isolates were very similar, but two clones each of S . enterica serovar Lomita and S . enterica serovar Ried were found . Badgers excreting S . enterica serovar Agama were spatially clustered. Appl Environ Microbiol, 2003 Jul, 69(7), 4123 - 8 Thermal inactivation of susceptible and multiantimicrobial-resistant salmonella strains grown in the absence or presence of glucose; Bacon RT et al.; The heat resistance of susceptible and multiantimicrobial-resistant Salmonella strains grown to stationary phase in glucose-free tryptic soy broth supplemented with 0.6% yeast extract (TSBYE-G; nonadapted), in regular (0.25% glucose) TSBYE, or in TSBYE-G with 1.00% added glucose (TSBYE+G; acid adapted) was determined at 55, 57, 59, and 61 degrees C . Cultures were heated in sterile 0.1% buffered peptone water (50 microl) in heat-sealed capillary tubes immersed in a thermostatically controlled circulating-water bath . Decimal reduction times (D values) were calculated from survival curves having r(2) values of >0.90 as a means of comparing thermal tolerance among variables . D(59 degrees C) values increased (P < 0.05) from 0.50 to 0.58 to 0.66 min for TSBYE-G, TSBYE, and TSBYE+G cultures, respectively . D(61 degrees C) values of antimicrobial-susceptible Salmonella strains increased (P < 0.05) from 0.14 to 0.19 as the glucose concentration increased from 0.00 to 1.00%, respectively, while D(61 degrees C) values of multiantimicrobial-resistant Salmonella strains did not differ (P > 0.05) between TSBYE-G and TSBYE+G cultures . When averaged across glucose levels and temperatures, there were no differences (P > 0.05) between the D values of susceptible and multiantimicrobial-resistant inocula . Collectively, D values ranged from 4.23 to 5.39, 1.47 to 1.81, 0.50 to 0.66, and 0.16 to 0.20 min for Salmonella strains inactivated at 55, 57, 59, and 61 degrees C, respectively . z(D) values were 1.20, 1.48, and 1.49 degrees C for Salmonella strains grown in TSBYE+G, TSBYE, and TSBYE-G, respectively, while the corresponding activation energies of inactivation were 497, 493, and 494 kJ/mol . Study results suggested a cross-protective effect of acid adaptation on thermal inactivation but no association between antimicrobial susceptibility and the ability of salmonellae to survive heat stress. Appl Environ Microbiol, 2003 Jul, 69(7), 4103 - 10 Ingestion of Salmonella enterica serotype Poona by a free-living mematode, Caenorhabditis elegans, and protection against inactivation by produce sanitizers; Caldwell KN et al.; Free-living nematodes are known to ingest food-borne pathogens and may serve as vectors to contaminate preharvest fruits and vegetables . Caenorhabditis elegans was selected as a model to study the effectiveness of sanitizers in killing Salmonella enterica serotype Poona ingested by free-living nematodes . Aqueous suspensions of adult worms that had fed on S . enterica serotype Poona were treated with produce sanitizers . Treatment with 20 microg of free chlorine/ml significantly (alpha = 0.05) reduced the population of S . enterica serotype Poona compared to results for treating worms with water (control) . However, there was no significant difference in the number of S . enterica serotype Poona cells surviving treatments with 20 to 500 microg of chlorine/ml, suggesting that reductions caused by treatment with 20 microg of chlorine/ml resulted from inactivation of S . enterica serotype Poona on the surface of C . elegans but not cells protected by the worm cuticle after ingestion . Treatment with Sanova (850 or 1,200 microg/ml), an acidified sodium chlorite sanitizer, caused reductions of 5.74 and 6.34 log(10) CFU/worm, respectively, compared to reductions from treating worms with water . Treatment with 20 or 40 microg of Tsunami 200/ml, a peroxyacetic acid-based sanitizer, resulted in reductions of 4.83 and 5.34 log(10) CFU/worm, respectively, compared to numbers detected on or in worms treated with water . Among the organic acids evaluated at a concentration of 2%, acetic acid was the least effective in killing S . enterica serotype Poona and lactic acid was the most effective . Treatment with up to 500 microg of chlorine/ml, 1% hydrogen peroxide, 2,550 microg of Sanova/ml, 40 microg of Tsunami 200/ml, or 2% acetic, citric, or lactic acid had no effect on the viability or reproductive behavior of C . elegans . Treatments were also applied to cantaloupe rind and lettuce inoculated with S . enterica serotype Poona or C . elegans that had ingested S . enterica serotype Poona . Protection of ingested S . enterica serotype Poona against sanitizers applied to cantaloupe was not evident; however, ingestion afforded protection of the pathogen on lettuce . These results indicate that S . enterica serotype Poona ingested by C . elegans may be protected against treatment with chlorine and other sanitizers, although the basis for this protection remains unclear. Appl Environ Microbiol, 2003 Jul, 69(7), 4098 - 102 Optimization of a reusable hollow-fiber ultrafilter for simultaneous concentration of enteric bacteria, protozoa, and viruses from water; Morales-Morales HA et al.; The detection and identification of pathogens from water samples remain challenging due to variations in recovery rates and the cost of procedures . Ultrafiltration offers the possibility to concentrate viral, bacterial, and protozoan organisms in a single process by using size-exclusion-based filtration . In this study, two hollow-fiber ultrafilters with 50,000-molecular-weight cutoffs were evaluated to concentrate microorganisms from 2- and 10-liter water samples . When known quantities (10(5) to 10(6) CFU/liter) of two species of enteric bacteria were introduced and concentrated from 2 liters of sterile water, the addition of 0.1% Tween 80 increased Escherichia coli strain K-12 recoveries from 70 to 84% and Salmonella enterica serovar Enteritidis recoveries from 36 to 72% . An E . coli antibiotic-resistant strain, XL1-Blue, was recovered at a level (87%) similar to that for strain K-12 (96%) from 10 liters of sterile water . When E . coli XL1-Blue was introduced into 10 liters of nonsterile Rio Grande water with higher turbidity levels (23 to 29 nephelometric turbidity units) at two inoculum levels (9 x 10(5) and 2.4 x 10(3) per liter), the recovery efficiencies were 89 and 92%, respectively . The simultaneous addition of E . coli XL1-Blue (9 x 10(5) CFU/liter), Cryptosporidium parvum oocysts (10 oocysts/liter), phage T1 (10(5) PFU/liter), and phage PP7 (10(5) PFU/liter) to 10 liters of Rio Grande surface water resulted in mean recoveries of 96, 54, 59, and 46%, respectively . Using a variety of surface waters from around the United States, we obtained recovery efficiencies for bacteria and viruses that were similar to those observed with the Rio Grande samples, but recovery of Cryptosporidium oocysts was decreased, averaging 32% (the site of collection of these samples had previously been identified as problematic for oocyst recovery) . Results indicate that the use of ultrafiltration for simultaneous recovery of bacterial, viral, and protozoan pathogens from variable surface waters is ready for field deployment. Appl Environ Microbiol, 2003 Jul, 69(7), 3945 - 51 Salmonella enterica serovar Typhimurium and Listeria monocytogenes acid tolerance response induced by organic acids at 20 degrees C: optimization and modeling; Greenacre EJ et al.; An acid tolerance response (ATR) has been demonstrated in Listeria monocytogenes and Salmonella enterica serovar Typhimurium in response to low pH poised (i.e., adapted) with acetic or lactic acids at 20 degrees C and modeled by using dynamic differential equations . The ATR was not immediate or prolonged, and optimization occurred after exposure of L . monocytogenes for 3 h at pH 5.5 poised with acetic acid and for 2 h at pH 5.5 poised with lactic acid and after exposure of S . enterica serovar Typhimurium for 2 h at pH 5.5 poised with acetic acid and for 3 h at pH 5.5 poised with lactic acid . An objective mechanistic analysis of the acid inactivation data yielded estimates of the duration of the shoulder (t(s)), the log-linear decline (k(max)), and the magnitude of a critical component (C) . The magnitude of k(max) gave the best agreement with estimates of conditions for optimum ATR induction made from the raw data. Acta Paediatr, 2003 May, 92(5), 537 - 40 Short-term ceftriaxone therapy for treatment of severe non-typhoidal Salmonella enterocolitis; Lin TY et al.; AIM: To evaluate the clinical efficacy of a short-course ceftriaxone therapy in the treatment of paediatric patients with severe non-typhoidal Salmonella enterocolitis . METHODS: During a 1 y period, all paediatric patients who were suspected having Salmonella enterocolitis by the presentation of bloody and/or mucoid diarrhoea with or without fever were eligible for the study . Patients with either negative stool cultures or bacteraemia were excluded . Severe enterocolitis was defined as a bloody and/or mucoid diarrhoea associated with high fever persisting for longer than 48 h and signs of moderate or severe dehydration . The patients with severe enterocolitis were assigned to treatment with ceftriaxone (50 mg kg(-1) d(-1)) for 3-5 d, while the rest were given supportive treatment only . Before treatment all study patients received blood testing for white blood cell (WBC) count, C-reactive protein (CRP) level and blood culture . The duration of the fevers was recorded . Patients were followed up after clinical recovery for the possibility of relapse . RESULTS: Seventy-three patients with culture-confirmed Salmonella enterocolitis without bacteraemia were analysed . The duration of fever was longer in severe cases who were treated with ceftriaxone than those who were not . However, rapid defervescene was found after short-course ceftriaxone therapy in those patients with severe enterocolitis . CRP was significantly higher in severe cases . There was no significant difference in the WBC count between the two groups of patients . No relapse was found in these patients . CONCLUSION: High CRP, prolonged high fever and signs of moderate or severe dehydration appear appropriate to define severe cases of Salmonella enterocolitis . Short-course ceftriaxone therapy is clinically beneficial to these patients . Neither clinical nor microbiological relapse was seen after therapy. Mikrobiyol Bul, 2003 Jan, 37(1), 41 - 7 {Typhoid fever epidemic in Ahmetli village, Diyarbakir-Ergani}; Ceylan A et al.; Salmonella typhi leads to typhoid fever outbreaks due to the contamination of drinking water . In this study, a typhoid fever outbreak due to drinking water contamination in Ahmetli village, Ergani-Diyarbakir, in the period of December 25, 2001-January 4, 2002 was evaluated . A total of 181 suspicious cases were admitted to different health care centers during the outbreak and 71 (39.2%) of them were hospitalized . Gruber-Widal test could be performed for only 8 hospitalized patients, and were found positive in 6 of them . S . typhi was isolated from 3 of the 26 blood cultures and two of the 73 stool cultures of the patients . All village inhabitants were visited and suspicious cases were screened for salmonellosis . It was shown that the village-drinking water was contaminated with sewage . No S . typhi was isolated from the drinking water since it was previously disinfected . Maintenance of drinking water supply system, individual chloride usage and education were recommended, as safety cushions. Mikrobiyol Bul, 2003 Jan, 37(1), 27 - 33 {In vitro susceptibility of Salmonella enterica serovar Typhimurium to reactive oxygen and nitrogen products}; Coban AY et al.; The aim of this study was to investigate the in-vitro susceptibility of Salmonella enterica serovar Typhimurium against reactive oxygen and nitrogen intermediates, on five different strains . SH5014 as a parental strain, PP120 as a soxRS mutant, SH7616 as a acrAB efflux pump mutant, SZH KUEN 557 as a standard strain and a clinical isolate, were included to the study . Hydrogen peroxide (at 0.125, 0.25, 0.5 mM concentrations) as reactive oxygen intermediate (ROI) and DETA-NO (at 1, 2, 4 mg/ml concentrations) as nitric oxide donor, in addition with acidified sodium nitrite (at 25, 50, 100 mM concentrations) as reactive nitrogen intermediate (RNI) were used . As a result, susceptibility of PP120 to RNI and ROI was found similar with SZH KUEN 557 and the clinical isolate, while SH7616 and SH5014 were found more susceptible than the others . These data indicated that further studies were necessary on the genetic regulatory systems in Salmonella which control the resistance against RNI and ROI-dependent antimicrobial systems. J Bacteriol, 2003 Jul, 185(14), 4243 - 7 Structural study of binding of flagellin by Toll-like receptor 5; Jacchieri SG et al.; In order to predict the binding regions within the complex formed by Toll-like receptor 5 (TLR-5) and flagellin, a complementary hydropathy between the two proteins was sought . A region common to the flagellins of Salmonella enterica serovar Typhimurium, Pseudomonas aeruginosa, and Listeria monocytogenes was shown to be hydropathically complementary to the 552-to-561 fragment of TLR-5, whose sequence is EILDISRNQL . The hydrophobicity profile of this region is shared with flagellins of 377 bacterial species out of a total of 723 publicly available sequences . A conformational analysis of the predicted binding site of TLR-5, whose structure is still unknown, was carried out with a methodology already applied to similar problems . To sample the conformations available to the peptide chain, a plot of the number of conformations per unit energy interval (density of states) versus energy was built . Following a theoretical argument, conformations belonging to maxima in this plot were selected . The most stable structure obtained in this search, an alpha-helical conformation, was shown to form the electrostatic interactions Glu552-Gln89, Asp555-Arg92, and Arg558-Glu93 with the predicted binding site of the flagellin of S . enterica serovar Typhimurium, formed by the 88-to-97 chain fragment (LQRVRELAVQ), which is likewise alpha helical. Mutat Res, 2003 Jul 8, 538(1-2), 145 - 54 Genotoxic hazards of long-term application of wastewater on agricultural soil; Aleem A et al.; In the city of Aligarh (India), wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the agricultural crops . This practice has been polluting the soil, and the pollutants could possibly reach the food chain . For the above reason, soil irrigated with wastewater was sampled and monitored for the presence of genotoxic agents using three biological assays namely Ames Salmonella/mammalian microsome test, survival of SOS defective E . coli K-12 mutants and bacteriophage lambda systems . Extracts from soils were prepared using different organic solvents, i.e . methanol, acetonitrile and acetone . TA98 was found to be most sensitive strain to all the soil extracts . A significant decline in the survival of DNA repair defective E . coli K-12 mutants as compared to their isogenic wild-type counterparts were observed when treated with soil extracts . PolA was found to be the most sensitive strain . A remarkable decline in the plaque forming units was also observed when tested with the soil extracts . Extracts of soil that has been irrigated with ground water were also tested by the above three biological assays to compare the results. Mutat Res, 2003 Jul 8, 538(1-2), 121 - 31 Mutagenic activity and quantification of nitroarenes in surface soil in the Kinki region of Japan; Watanabe T et al.; To clarify the mutagenic potential of surface soil in the Kinki region of Japan, particularly in Osaka and neighboring cities, 62 surface soil samples were collected and their organic extracts were examined by the Ames/Salmonella assay . All of the samples were mutagenic toward TA98 in both the presence and absence of a mammalian metabolic activation system (S9 mix) . While all of the samples showed mutagenicity toward TA100 with S9 mix, only 45/62 (73%) were mutagenic without S9 mix . Fifty (81%) of the samples showed higher activity toward TA98 than TA100 . The mean values of the mutagenicities of soil samples collected in Osaka prefecture (n=35) toward TA98 with and without S9 mix were 2315 and 1630 revertants per gram of soil, respectively, and these were 2.9 and 2.6 times as high as the values for samples from other prefectures (n=27), respectively . Three dinitropyrene (DNP) isomers, i.e . 1,3-, 1,6- and 1,8-DNP, and 3-nitrobenzanthrone (NBA) in the surface soil samples were quantified by fluorometric detection of the corresponding amino compounds, i.e . diaminopyrene isomers and 3-aminobenzanthrone, using high-performance liquid chromatography (HPLC) . The three DNP isomers were detected in all of the soil samples (n=26) that were mainly collected in Osaka prefecture, and the amounts of 1,3-, 1,6- and 1,8-DNP were 6-1526, 11-1772 and 10-2092pg/g of soil, respectively . The contribution ratios of 1,3-, 1,6- and 1,8-DNP to the mutagenicity of soil extracts toward TA98 without S9 mix were 0.2-12, 0.3-12 and 0.5-27%, respectively . The amount of 3-NBA in soil samples (n=8) was 144-1158pg/g of soil, and the contribution ratio of 3-NBA to the mutagenicity of soil extracts was 2-38% . These results suggest that the surface soils in the Kinki region were highly polluted with mutagens and the pollution levels in Osaka prefecture were higher than those in other areas . DNP isomers and 3-NBA may be major mutagens that contaminate surface soil in this region. Trop Gastroenterol, 2002 Oct-Dec, 23(4), 181 - 2 Hepatic abscess complicating paratyphoid infection; Rajagopal A et al.; Salmonellosis is ubiquitous and is a world-wide public health concern . Liver abscesses are occasionally reported in Salmonella typhi infections, they are a very rare complication of Salmonella paratyphi infections . A 28 year old male patient without any prior medical history presented with fever, abdominal pain and a tender hepatomegaly . The imaging studies revealed multiple liver abscesses and an ultrasound (US) guided aspiration of the abscess yielded heavy growth of Salmonella paratyphi A . He was treated successfully by percutaneous drainage of the abscesses and appropriate antibiotics. FEMS Immunol Med Microbiol, 2003 Jul 15, 37(2-3), 105 - 9 T cell receptor-transgenic mouse models for studying cellular immune responses to Salmonella in vivo; Bumann D; Cellular immune responses are crucial both for protective immunity against salmonellosis, and for the immunogenicity of oral vaccines based on avirulent live Salmonella as antigen carriers . The crucial early steps of T cell induction are difficult to investigate in conventional animals, but recently developed T cell receptor (TCR)-transgenic models allow visualization of antigen-specific T cells in vivo while they become induced . In this review, the results obtained with four different TCR-transgenic Salmonella infection models are described, and advantages and potential limits of each of the different models are compared. FEMS Immunol Med Microbiol, 2003 Jul 15, 37(2-3), 87 - 98 Secretory delivery of recombinant proteins in attenuated Salmonella strains: potential and limitations of Type I protein transporters; Hahn HP et al.; Live attenuated Salmonella strains have been extensively explored as oral delivery systems for recombinant vaccine antigens and effector proteins with immunoadjuvant and immunomodulatory potential . The feasibility of this approach was demonstrated in human vaccination trials for various antigens . However, immunization efficiencies with live vaccines are generally significantly lower compared to those monitored in parenteral immunizations with the same vaccine antigen . This is, at least partly, due to the lack of secretory expression systems, enabling large-scale extracellular delivery of vaccine and effector proteins by these strains . Because of their low complexity and the terminal location of the secretion signal in the secreted protein, Type I (ATP-binding cassette) secretion systems appear to be particularly suited for development of such recombinant extracellular expression systems . So far, the Escherichia coli hemolysin system is the only Type I secretion system, which has been adapted to recombinant protein secretion in Salmonella . However, this system has a number of disadvantages, including low secretion capacity, complex genetic regulation, and structural restriction to the secreted protein, which eventually hinder high-level in vivo delivery of recombinant vaccines and effector proteins . Thus, the development of more efficient recombinant protein secretion systems, based on Type I exporters can help to improve efficacies of live recombinant Salmonella vaccines . Type I secretion systems, mediating secretion of bacterial surface layer proteins, such as RsaA in Caulobacter crescentus, are discussed as promising candidates for improved secretory delivery systems. Jpn J Thorac Cardiovasc Surg, 2003 Jun, 51(6), 253 - 5 Mycotic aneurysm of the aortic arch due to Salmonella; Nakamura Y et al.; We report the successful treatment of a 79-year-old man with an extremely rare mycotic aneurysm of the aortic arch due to Salmonella . The patient presented with persistent fever, hoarseness, and hemosputum . Computed tomography showed a large saccular aneurysm with a hazy aortic wall in the aortic arch . We conducted emergency total arch replacement, debriding surrounding infectious tissue . Cultures from the aneurysm grew Salmonella enteritidis . Infection recurred 1 week postoperatively, requiring open irrigation and omentum transposition . These surgical procedures, along with appropriate antibiotics, brought infection under control. Clin Infect Dis, 2003 Jul 1, 37(1), 141 - 4 Epub 2003 Jun 24. Sexual transmission of typhoid fever: a multistate outbreak among men who have sex with men; Reller ME et al.; In August 2000, the Ohio Department of Health reported a cluster of men with typhoid fever who denied having traveled abroad . To determine the cause and the extent of the outbreak, an epidemiological investigation was initiated in which 7 persons in Ohio, Kentucky, and Indiana with culture-confirmed Salmonella enterica serotype Typhi infection and 2 persons with probable typhoid fever were evaluated; all were men, and all but one reported having had sex with 1 asymptomatic male S . Typhi carrier . We document sexual transmission of typhoid fever, which may be acquired by means of oral and anal sex, as well as via food and drink. Clin Infect Dis, 2003 Jul 1, 37(1), 137 - 40 Epub 2003 Jun 24. Interleukin-12 receptor beta1 deficiency presenting as recurrent Salmonella infection; Staretz-Haham O et al.; We describe a child with interleukin-12 receptor beta1 (IL-12Rbeta1) deficiency caused by a homozygous IL12RB1 large deletion who presented at the age of 1 year with recurrent, often asymptomatic episodes of bacteremia caused by group D Salmonella species . No mycobacterial disease or other unusual infection was present . The episodes of salmonellosis were caused by an identical serovar during a period of 18 months . This is the first case of inherited IL-12Rbeta1 deficiency diagnosed after isolated, recurrent salmonellosis. Clin Infect Dis, 2003 Jul 1, 37(1), 75 - 81 Epub 2003 Jun 20. Reevaluating fluoroquinolone breakpoints for Salmonella enterica serotype Typhi and for non-Typhi salmonellae; Crump JA et al.; Salmonella enterica infections cause considerable morbidity and mortality worldwide . Antimicrobial therapy may be life-saving for patients with extraintestinal infections with S . enterica serotype Typhi or non-Typhi salmonellae . Because antimicrobial resistance to several classes of traditional first-line drugs has emerged in the past several decades, the quinolone antimicrobial agents, particularly the fluoroquinolones, have become the drugs of choice . Recently, resistance to nalidixic acid has emerged among both Typhi and non-Typhi Salmonella serotypes . Such Salmonella isolates typically also have decreased susceptibility to fluoroquinolones, although minimum inhibitory concentrations of the fluoroquinolones usually are within the susceptible range of the interpretive criteria of the NCCLS . A growing body of clinical and microbiological evidence indicates that such nalidixic acid-resistant S . enterica infections also exhibit a decreased clinical response to fluoroquinolones . In this article, we recommend that laboratories test extraintestinal Salmonella isolates for nalidixic acid resistance, we recommend that short-course fluoroquinolone therapy be avoided for infection with nalidixic acid-resistant extraintestinal salmonellae, and we summarize existing data and data needs that would contribute to reevaluation of the current NCCLS fluoroquinolone breakpoints for salmonellae. Proc Natl Acad Sci U S A, 2003 Jul 8, 100(14), 8496 - 501 Epub 2003 Jun 26. Inhibition of bacterial DNA replication by zinc mobilization during nitrosative stress; Schapiro JM et al.; Phagocytic cells inhibit the growth of intracellular pathogens by producing nitric oxide (NO) . NO causes cell filamentation, induction of the SOS response, and DNA replication arrest in the Gram-negative bacterium Salmonella enterica . NO also induces double-stranded chromosomal breaks in replication-arrested Salmonella lacking a functional RecBCD exonuclease . This DNA damage depends on actions of additional DNA repair proteins, the RecG helicase, and RuvC endonuclease . Introduction of a recG mutation restores both resistance to NO and the ability of an attenuated recBC mutant Salmonella strain to cause lethal infection in mice, demonstrating that bacterial DNA replication is inhibited during host-pathogen interactions . Inhibition of DNA replication during nitrosative stress is invariably accompanied by zinc mobilization, implicating DNA-binding zinc metalloproteins as critical targets of NO-related antimicrobial activity. FEMS Microbiol Lett, 2003 Jun 27, 223(2), 281 - 6 Retron reverse transcriptase rrtT is ubiquitous in strains of Salmonella enterica serovar Typhimurium; Matiasovicova J et al.; Bacterial retron reverse transcriptases are unusual enzymes which utilise the same RNA molecule as a template and also as a primer for initiation of the reverse transcription . Except for their relatively frequent presence in Myxococcus spp., they are considered as quite rare proteins . However, in this study we proved that retron reverse transcriptase is frequently found in certain serovars of Salmonella enterica . Using polymerase chain reaction (PCR), in strains of serovar Typhimurium, the rrtT (retron reverse transcriptase Typhimurium) gene was detected in 158 out of 175 tested field strains . On the other hand, in none of the 18 tested serovar Enteritidis strains the rrtT was detected in their genome . Detailed computer analysis allowed us to predict the sequence of msDNA and to propose that the final msDNA is free of any RNA . Furthermore, we predict that there are at least three different classes of retron reverse transcriptases. FEMS Microbiol Lett, 2003 Jun 27, 223(2), 259 - 65 Development of a novel method of lytic phage delivery by use of a bacteriophage P22 site-specific recombination system; Platt R et al.; Bacteriophage therapy represents a potential alternative to the use of antibiotics to control proliferation of pathogenic bacteria . As an alternative to the strategy where a limited number of doses of large numbers of lytic bacteriophages are administered, a novel method delivery system was developed so that phages are continually released into the culture . Specifically, a non-pathogenic Escherichia coli strain was constructed that was lysogenic for a lytic mutant of bacteriophage lambda . This lysogen was shown to be effective at decreasing the number of lambda-sensitive E . coli in vitro . Construction of this E . coli strain was accomplished by development of a plasmid-based system utilizing the site-specific recombination machinery of bacteriophage P22 to integrate DNA constructs into the host chromosome . This recombination system is useful for strain construction and other genetic manipulations in both E . coli and Salmonella enterica serovars. FEMS Microbiol Lett, 2003 Jun 27, 223(2), 231 - 8 Involvement of intestinal inducible nitric oxide synthase (iNOS) in the early stages of murine salmonellosis; Giacomodonato MN et al.; Local induction of inducible nitric oxide synthase (iNOS) and apoptosis was examined in the intestine of mice infected with virulent Salmonella enterica serovar Enteritidis 5694 (S . enteritidis) and its attenuated derivative mutant E/1/3 . Both, intestinal iNOS mRNA expression and iNOS activity showed a peak at 4 h only in animals receiving the virulent S . enteritidis . Aminoguanidine treatment abrogated intestinal epithelial damage produced by virulent S . enteritidis and diminished apoptosis at the tips of the villi . Unlike the virulent strain, mutant E/1/3 induced massive iNOS expression in Peyer's patches, these findings may be related to its protective capacity . Our results suggest that intestinal iNOS participates in the early response to intestinal infection and that the final effect depends on the nature of the insult. FEMS Microbiol Rev, 2003 Jun, 27(2-3), 263 - 90 Emerging themes in manganese transport, biochemistry and pathogenesis in bacteria; Kehres DG et al.; Though an essential trace element, manganese is generally accorded little importance in biology other than as a cofactor for some free radical detoxifying enzymes and in the photosynthetic photosystem II . Only a handful of other Mn2+-dependent enzymes are known . Recent data, primarily in bacteria, suggest that Mn2+-dependent processes may have significantly greater physiological importance . Two major classes of prokaryotic Mn2+ uptake systems have now been described, one homologous to eukaryotic Nramp transporters and one a member of the ABC-type ATPase superfamily . Each is highly selective for Mn2+ over Fe2+ or other transition metal divalent cations, and each can accumulate millimolar amounts of intracellular Mn2+ even when environmental Mn2+ is scarce . In Salmonella enterica serovar Typhimurium, simultaneous mutation of both types of transporter results in avirulence, implying that one or more Mn2+-dependent enzymes is essential for pathogenesis . This review summarizes current literature on Mn2+ transport, primarily in the Bacteria but with relevant comparisons to the Archaea and Eukaryota . Mn2+-dependent enzymes are then discussed along with some speculations as to their role(s) in cellular physiology, again primarily in Bacteria . It is of particular interest that most of the enzymes which interconvert phosphoglycerate, pyruvate, and oxaloacetate intermediates are either strictly Mn2+-dependent or highly stimulated by Mn2+ . This suggests that Mn2+ may play an important role in central carbon metabolism . Further studies will be required, however, to determine whether these or other actions of Mn2+ within the cell are the relevant factors in pathogenesis. Mol Microbiol, 2003 Jul, 49(2), 425 - 39 The purified Shigella IpaB and Salmonella SipB translocators share biochemical properties and membrane topology; Hume PJ et al.; An essential early event in Shigella and Salmonella pathogenesis is invasion of non-phagocytic intestinal epithelial cells . Pathogen entry is triggered by the delivery of multiple bacterial effector proteins into target mammalian cells . The Shigella invasion plasmid antigen B (IpaB), which inserts into the host plasma membrane, is required for effector delivery and invasion . To investigate the biochemical properties and membrane topology of IpaB, we purified the native full-length protein following expression in laboratory Escherichia coli . Purified IpaB assembled into trimers via an N-terminal domain predicted to form a trimeric coiled-coil, and is predominantly alpha-helical . Upon lipid interaction, two transmembrane domains (residues 313-333 and 399-419) penetrate the bilayer, allowing the intervening hydrophilic region (334-398) to cross the membrane . Purified IpaB integrated into model, erythrocyte and mammalian cell membranes without disrupting bilayer integrity, and induced liposome fusion in vitro . An IpaB-derived 162 residue alpha-helical polypeptide (IpaB(418-580)) is a potent inhibitor of IpaB-directed liposome fusion in vitro and blocked Shigella entry into cultured mammalian cells at 10(-8) M . It is also a heterologous inhibitor of Salmonella invasion protein B (SipB) activity and Salmonella entry . In contrast, IpaB(418-580) failed to prevent the contact-dependent haemolytic activity of Shigella . These findings question the proposed direct link between contact-dependent haemolysis and Shigella entry, and demonstrate that IpaB and SipB share biochemical properties and membrane topology, consistent with a conserved mode of action during cell entry. Br Poult Sci, 2003 May, 44(2), 192 - 202 Isolation and characterisation of Salmonella in a turkey production facility; Nayak R et al.; 1 . A comprehensive ecological survey was conducted from April 1997 to June 1999 on 4 turkey flocks (F1 to F4) to identify key pre-harvest sources/vectors of Salmonella colonisation . 2 . Turkey caecal and crop content, litter, drinker, air, feed, feeder and environmental swab samples were collected . Conventional microbiological and serological procedures were used to isolate, identify, and confirm the presence or absence of Salmonella . 3 . Salmonella was isolated from 13% of litter, 11% of turkey caeca, 10% of drinker, 5% of environmental swab, 3% of feed and 1% of feeder samples . Salmonella heidelberg (65%), S . senftenberg (19%), S . muenster (10%), S . anatum (3%), and S . worthington (3%) were identified . 4 . Identifying environmental sources associated with Salmonella colonisation and characterising serotypes would assist in designing pre-harvest controls for this poultry-borne pathogen . Integrators and poultry producers may be able to design hazard analysis and critical control point (HACCP) protocols to reduce the incidence of Salmonella arriving at the processing plant. Sci Total Environ, 2003 Jul 20, 311(1-3), 49 - 56 Occurrence of pathogens on vegetables harvested from soils irrigated with contaminated streams; Okafo CN et al.; The study assesses the contamination level, the seasonal distribution and the toxigenicity of pathogens isolated from irrigated vegetables and the water used for irrigation . A total of 196 samples of water used for irrigation and 326 irrigated vegetables were obtained from Kawo drain, Sabon Gari drain and River Galma and examined using standard procedures for coliform and viable counts and the presence of E . coli, Salmonella and Vibrio during the dry and wet seasons . Irrigation water from Kawo drain had significantly higher coliform counts by location and season than water from the other two locations . Although all the vegetables had coliform counts higher than the recommended standard (range 3.40-6.38 log(10) cfuml(-1)), amaranthus had significantly higher (P<0.05) counts than other vegetables during the dry season . Salmonella was significantly more likely to be detected during the dry season than during the wet (OR 4.91, 1.07<OR<31.16) . Of the 39 enteropathogenic E . coli isolated, 15 (38.5%) were toxigenic by ileal loop test . There is need to educate farmers on the risk involved in the use of waste contaminated water for irrigation . The need to wash and disinfect raw vegetables before consumption is stressed. Plasmid, 2003 Jul, 50(1), 12 - 27 Display and release of the Plasmodium falciparum circumsporozoite protein using the autotransporter MisL of Salmonella enterica; Ruiz-Olvera P et al.; The Salmonella enterica MisL (protein of membrane insertion and secretion) is an autotransporter with high homology to AIDA-I (adhesin involved in diffuse adherence) of enteropathogenic Escherichia coli . Considering that it has been reported that the MisL beta translocator domain is able to display heterologous passenger peptides to the bacterial surface, we developed a system to display proteins and release them to the external environment by means of proteolytic cleavage . Plasmids were constructed encoding 8 or 53 repeats of the NANP (Asp-Ala-Asp-Pro) tetrapeptide, which is the main B cell epitope of the Plasmodium falciparum circumsporozoitic protein (CSP), fused to the the MisL beta-domain and including the recognition cleavage sequence from the E . coli OmpT surface protease . E . coli XL-10Gold and BL21(DE3) (OmpT positive and negative, respectively) and Salmonella enterica serovar Typhimurium SL3261 (Aro A(-)) were transformed with the plasmids and, both expression and localization of the fusion proteins were assessed by Western blot, indirect immunofluorescence, and flow cytometry, using a monoclonal antibody against (NANP)(3) . Higher expression of the (NANP)(8) and (NANP)(53) fusion proteins was demonstrated on the bacterial surface of the OmpT negative E . coli strains and the (NANP)(53) in the culture supernatant of E . coli XL-10Gold indicating a protease mediated cleavage . The flow cytometry analysis suggested 71 and 98% cleavage efficiency for the (NANP)(8) and (NANP)(53), respectively, in E . coli XL-10Gold . Similar results were obtained in S . enterica serovar Typhimurium SL3261, suggesting the involvement of other proteases related to OmpT . These results demonstrate that MisL may be used for the autodisplay and release of passenger proteins in attenuated Salmonella or E . coli strains, which may have several applications in vaccine design. Epidemiol Infect, 2003 Jun, 130(3), 387 - 93 A national outbreak of infection with Salmonella enteritidis phage types 5c and 6a associated with Chinese food businesses in Scotland, summer 2000; Cowden J et al.; An outbreak of salmonellosis, involving cases of infection with Salmonella enteritidis phage types (PT) 5c and 6a, occurred across Scotland between May and August 2000 . In total, 70 outbreak cases were microbiologically confirmed . Preliminary investigation suggested that consumption of food, especially chicken dishes, from Chinese restaurants or take-aways (food businesses) was a risk factor for infection . A matched case-control study demonstrated a statistically significant association (OR 22.4, P=0.0024) between infection and consumption of food from Chinese food businesses . A cohort study of novel design suggested that chicken was an important vehicle of infection . However the result did not reach statistical significance (OR 1.7, P=0.3) . Extensive environmental investigation was unable to identify the source of the suspected contaminated chicken. Vet Pathol, 2003 Jul, 40(4), 371 - 5 Comparison of early ileal invasion by Salmonella enterica serovars Choleraesuis and Typhimurium; Meyerholz DK et al.; The mechanisms of Salmonella serovar-host specificity are not well defined . Pig ileal loops were used to compare phenotypic differences in early cellular invasion between non-host-adapted Salmonella serovar Typhimurium (SsT) and host-adapted Salmonella serovar Choleraesuis (SsC) . By 10 minutes postinoculation, both serovars invaded a small number of M cells, enterocytes, and goblet cells . Multiple SsC organisms (up to 6 per cell) simultaneously invaded M cells, whereas SsT often invaded as one to two organisms per M cell . Internalization of both serovars resulted in vacuoles containing a single bacterium . The follicle-associated epithelium (FAE) of SsC-inoculated loops responded with more filopodia and lamellipodia although exhibiting less cell swelling than SsT . Additionally, SsT showed an enhanced affinity for sites of cell extrusion compared with SsC at 60 minutes . These results suggest: 1) both SsC and SsT exhibit non-cell-specific invasion as early as 10 minutes postinoculation, 2) Salmonella serovars exhibit differences in early invasion of FAE and M cells, and 3) cells undergoing extrusion may provide a site for preferential adherence by SsT and SsC. J Biol Chem, 2003 Aug 29, 278(35), 32602 - 7 Epub 2003 Jun 24. Regulation of dinucleoside polyphosphate pools by the YgdP and ApaH hydrolases is essential for the ability of Salmonella enterica serovar typhimurium to invade cultured mammalian cells; Ismail TM et al.; The ygdP and apaH genes of Salmonella enterica serovar Typhimurium (S . Typhimurium) encode two unrelated dinucleoside polyphosphate (NpnN) hydrolases . For example, YgdP cleaves diadenosine tetraphosphate (Ap4A) producing AMP and ATP, while ApaH cleaves Ap4A producing 2ADP . Disruption of ygdP, apaH individually, and disruption of both genes together reduced intracellular invasion of human HEp-2 epithelial cells by S . Typhimurium by 9-, 250-, and 3000-fold, respectively . Adhesion of the mutants was also greatly reduced compared with the wild type . Invasive capacity of both single mutants was restored by transcomplementation with the ygdP gene, suggesting that loss of invasion was due to increased intracellular NpnN . The normal level of 3 microM adenylated NpnN (ApnN) was increased 1.5-, 3.5-, and 10-fold in the ygdP, apaH and double mutants, respectively . Expression of the putative ptsP virulence gene downstream of ygdP was not affected in the ygdP mutant . Analysis of 19 metabolic enzyme activities and the ability to use a range of carbohydrate carbon sources revealed a number of differences between the mutants and wild type . The increase in intracellular NpnN in the mutants appears to cause changes in gene expression that limit the ability of S . Typhimurium to adhere to and invade mammalian cells. Trends Microbiol, 2003 Jun, 11(6), 245 - 6; discussion 247-8 Molecular call-and-response: how Salmonella learns the gospel from its host; Dangl JL; Host-microbe interactions are often portrayed as a game of molecular hide-and-seek or tug-of-war where one partner seeks to establish an upper-hand over the other . Perhaps a more useful analogy is the traditional call-and-response preaching method used so effectively in churches of the southern USA to encourage participation by the assembled parishioners . The preacher calls out a line of a gospel or hymn and the congregation responds as one to the cue . A recent paper identifies Nramp as a potential molecular preacher, and Salmonella, and probably other pathogenic bacteria, are singing back full-throated. J Agric Food Chem, 2003 Jul 2, 51(14), 3958 - 65 In vitro antibacterial, antifungal, and antioxidant activities of the essential oil and methanol extracts of herbal parts and callus cultures of Satureja hortensis L; Gulluce M et al.; The present study was designated to evaluate the antimicrobial and antioxidant activities of the essential oil, obtained by using a Clevenger distillation apparatus, water soluble (polar) and water insoluble (nonpolar) subfractions of the methanol extracts from aerial parts of Satureja hortensis L . plants, and methanol extract from calli established from the seeds using Gamborg's B5 basal media supplemented with indole-3-butyric acid (1.0 ppm), 6-benzylaminopurine (N(6)-benzyladenine) (1.0 ppm), and sucrose (2.5%) . The antimicrobial test results showed that the essential oil of S . hortensis had great potential antimicrobial activities against all 23 bacteria and 15 fungi and yeast species tested . In contrast, the methanol extract from callus cultures and water soluble subfraction of the methanol extract did not show antimicrobial activities, but the nonpolar subfraction had antibacterial activity against only five out of 23 bacterial species, which were Bacillus subtilis, Enterococcus fecalis, Pseudomonas aeruginosa, Salmonella enteritidis, and Streptococcus pyogenes . Antioxidant studies suggested that the polar subfractions of the methanol extract of intact plant and methanol extract of callus cultures were able to reduce the stable free radical 2,2-diphenyl-1-picrylhydrazyl to the yellow-colored diphenylpicrylhydrazine . In this assay, the strongest effect was observed for the tissue culture extract, with an IC(50) value of 23.76 +/- 0.80 microgram/mL, which could be compared with the synthetic antioxidant agent butylated hydroxytoluene . On the other hand, linoleic acid oxidation was 95% inhibited in the presence of the essential oil while the inhibition was 90% with the chloroform subfraction of the intact plant . The chemical composition of a hydrodistilled essential oil of S . hortensis was analyzed by gas chromatography (GC)/flame ionization detection (FID) and a GC-mass spectrometry system . A total 22 constituents representing 99.9% of the essential oil were identified by GC-FID analaysis . Thymol (29.0%), carvacrol (26.5%), gamma-terpinene (22.6%), and p-cymene (9.3%) were the main components. Epidemiol Mikrobiol Imunol, 2003 Apr, 52(2), 66 - 71 {Multiresistant Salmonella enterica subspecies enterica serovar Typhimurium DT104 in the Czech republic 2000-2001}; Sramova H et al.; Salmonelloses belong to the most important alimentary diseases . From 1989 the main source of infection is S . Enteritidis (95% and more) . The ratio of S . Typhimurium in the etiology declined gradually since 1994 from 3% in 1993 to 1.9% in 2001 . The number of detected multiresistant strains STM DT104 is so far low in the Czech Republic . In 2000 laboratory tests confirmed 53 and in 2001 a total of 63 strains . Analysis of these strains revealed: 1 . the proportion of multiresistant strains STM DT104 of the total number of isolated STM strains increased from 7% in 2000 to 11.5% in 2001, 2 . the territory in the CR where these multiresistant strains were found expanded, 3 . the relationship of proportions of the most frequently detected STM phagotypes in the human population changes: in 2000 this ratio was balanced, in 2001 the ratio of phagotype DT104 is roughly three times higher than of DT 141, 4 . analysis of all STM strains from the environment and animals indicates that the frequency of STM DT104 is 73% . Almost 90% of these strains are multiresistant (resistant to one or several antimicrobial substances) . The highest number was found in calves, piglets but also in poultry . With regard to the results of the submitted work it is important to concentrate attention on detection and further laboratory examination of STM strains in the human and animal population. Med Arh, 2003, 57(2), 87 - 92 Acute infectious diarrhea in children; Ahmetagic S et al.; INTRODUCTION: Acute infectious diarrhea is a global health problem especially in infants and children, and is a leading cause of morbidity and mortality . The ethiology of acute infectious diarrhea and also biochemical, epidemiological and clinical characteristics of children dying with infectious diarrhea are investigated in this study . METHODS: 201 children, aged from 6 months to 14 years, with acute infectious diarrhea admitted to the Infectious Diseases Clinic in Tuzla in the period from 21st December 1999 to 21st December 2000 were included in the study . RESULTS: Enteropathogens were identified in stool samples in 103 (51.3%) of 201 examined children . Viruses were identified in 51 (25.4%) cases, bacteria in 44 (21.9%), fungi in 3 (1.5%), and parasites in 2 (1%) . Rotavirus, a frequent pathogen, was detected in 48 cases (23.9%), followed by Salmonella species in 20 (10%), EPEC in 10 (4.9%), and Shigella species in 9 (4.5%) cases . In this study the authors noticed that the highest morbidity was recorded in children in the first 2 years of life (70.5%), and among rural community (68.4%) . The detection of rotavirus decreased with increasing age of cases and peaked in winter and autumn . Blood in stool was most common in children with shigellosis (22.2%) . CONCLUSIONS: High percentage of infants and children dying with acute infectious diarrhea presents a serious socio-economic and medical problem in Tuzla region of Bosnia and Herzegovina . Rotavirus is the single most common pathogen in children with infectious diarrhea. Curr Opin Infect Dis, 2003 Jun, 16(3), 241 - 6 Calicivirus infections in children; Matson DO et al.; PURPOSE OF REVIEW: Caliciviruses are a major cause of human illness, and are listed as category B pathogens according to the National Institute of Allergy and Infectious Diseases classification of pathogens important for biodefense . Caliciviruses are commonly encountered in contaminated food and water, and a large variety has been implicated as sources of infection during outbreak investigations . RECENT FINDINGS: New names for two of the four genera of the Caliciviridae were approved in 2002 . They are Norovirus, for what were previously called Norwalk-like viruses or small, round-structured viruses, and Sapovirus, for what were previously called Sapporo-like viruses . Caliciviruses are highly diverse genetically and antigenically . This diversity complicates the design of diagnostic assays, yet can be used to discriminate contaminating and infecting strains during outbreak investigations . Of particular interest is the recent finding of naturally occurring recombinant Norovirus strains, all of which have been virulent and are widely dispersed and apparently ecologically indistinguishable from other calicivirus strains . This finding is considered in light of the evidence for recombination between caliciviruses and picornaviruses, and recombination as a more general phenomenon for virus evolution . SUMMARY: Continued investigations of calicivirus outbreaks are now focusing on the implicated sources of infection . While many foods and environmental waters have long been implicated as outbreak sources, the methods for detecting caliciviruses are being developed and refined . Recognition is now turning to unexpected sources of contamination, such as presumably clean foods and waters, including bottled water and minimally handled foods . Parallels between Norovirus and Salmonella ecology and epidemiology are noted, as a guide to understanding evolving new information about caliciviruses. Microb Drug Resist, 2003 Summer, 9(2), 183 - 9 A comparison of antimicrobial susceptibilities in nontyphoidal salmonellas from humans and food animals in England and Wales in 2000; Threlfall EJ et al.; A joint study by the Public Health Laboratory Service and the Veterinary Laboratories Agency of resistance to antimicrobials in isolates of Salmonella enterica serotypes Enteritidis, Typhimurium, Hadar, and Virchow from humans and food-producing animals in England and Wales in 2000 has demonstrated that resistance was most common in Typhimurium, particularly in strains of definitive phage type (DT) 104 . However resistance was also common in other phage types, particularly DTs 193 and 208 and phage type U302 . Multiresistant strains of DT208 appeared to be predominantly associated with pigs; for the other phage types, the human/food-producing animal relationships of drug-resistant isolates were more complex . For Enteritidis, Virchow, and Hadar, there were substantial differences in the resistance spectra of isolates from humans and food-producing animals, suggesting that food-producing animals bred in England and Wales may not be the primary sources of drug-resistant strains of these serotypes causing infections in humans . Further phenotypic and molecular comparison of drug-resistant isolates of these serotypes may be required to ascertain the sources of strains responsible for infections in humans. Pediatr Radiol, 2003 Jul, 33(7), 492 - 4 Epub 2003 Mar 01. Pyomyositis of the vastus medialis muscle associated with Salmonella enteritidis in a child; Minami K et al.; We describe a 23-month-old boy with pyomyositis of the vastus medialis muscle caused by Salmonella enteritidis . Such focal Salmonella infections are uncommon in soft tissue . It is noteworthy of this case that there were no antecedent signs of gastroenteritis and no underlying medical condition . MRI, in particular the fat-suppressed T2-weighted sequence, is helpful for establishing the diagnosis and differentiating pyomyositis from other pathological conditions. Infect Immun, 2003 Jul, 71(7), 4163 - 6 Helicobacter pylori preferentially induces interleukin 12 (IL-12) rather than IL-6 or IL-10 in human dendritic cells; Guiney DG et al.; Dendritic cells are potent antigen-presenting cells that are present in the gastrointestinal tract and are required for the induction of a Th1 T-cell acquired immune response . Since infection with the gastric pathogen Helicobacter pylori elicits a Th1 cell response, the interaction of these organisms with dendritic cells should reflect the Th1 bias . We incubated H . pylori with cultured human dendritic cells and measured the cytokine induction profile, comparing the response to that induced by Salmonella enterica serovar Typhimurium . We found that H . pylori induced little interleukin 6 (IL-6) and essentially no IL-10 in contrast to S . enterica . However, H . pylori induced levels of IL-12 that were 30% of those induced by S . enterica, indicating a Th1 response . An isogenic cagE mutant of H . pylori lost about 50% of its IL-12-inducing ability, suggesting a role for the cag type IV secretion system in the stimulation of dendritic cells. Infect Immun, 2003 Jul, 71(7), 4102 - 11 CD44-regulated intracellular proliferation of Listeria monocytogenes; Eriksson E et al.; CD44 has been implicated in immune and inflammatory processes . We have analyzed the role of CD44 in the outcome of Listeria monocytogenes infection in murine bone marrow-derived macrophages (BMM) . Surprisingly, a dramatically decreased intracellular survival of L . monocytogenes was observed in CD44(-/-) BMM . CD44(-/-) heart or lung fibroblast cultures also showed reduced bacterial levels . Moreover, livers from CD44(-/-)-infected mice showed diminished levels of L . monocytogenes . In contrast, intracellular growth of Salmonella enterica serovar Typhimurium was the same in CD44(-/-) and control BMM . The CD44-mediated increased bacterial proliferation was not linked to altered BMM differentiation or to secretion of soluble factors . CD44 did not mediate listerial uptake, and it played no role in bacterial escape from the primary phagosome or formation of actin tails . Furthermore, CD44-enhanced listerial proliferation occurred in the absence of intracellular bacterial spreading . Interestingly, coincubation of BMM with hyaluronidase or anti-CD44 antibodies that selectively inhibit hyaluronan binding increased intracellular listerial proliferation . Treatment of cells with hyaluronan, in contrast, diminished listerial growth and induced proinflammatory transcript levels . We suggest that L . monocytogenes takes advantage of the CD44-mediated signaling to proliferate intracellularly, although binding of CD44 to certain ligands will inhibit such response. Infect Immun, 2003 Jul, 71(7), 4052 - 8 A Salmonella enterica serovar typhimurium translocated leucine-rich repeat effector protein inhibits NF-kappa B-dependent gene expression; Haraga A et al.; Nontyphoidal salmonellae are enteric pathogens that cause acute gastroenteritis and colonize the intestinal tract for prolonged periods . In the intestinal epithelia, these bacteria induce secretion of proinflammatory cytokines, such as interleukin-8 (IL-8), which leads to a profound inflammatory response through recruitment of polymorphonuclear leukocytes . Production of IL-8 induced by Salmonella spp . is due to the activation of the transcription factors nuclear factor kappa B (NF-kappa B) and activator protein-1 (AP-1) . This work demonstrates that Salmonella enterica serovar Typhimurium can downmodulate IL-8 production after invasion of intestinal epithelial cells . The Salmonella translocated effector proteins SspH1 and SptP participate in this process . SspH1 is a member of the bacterial LPX repeat protein family that localizes to the mammalian nucleus and inhibits NF-kappa B-dependent gene expression . A Shigella flexneri translocated effector, IpaH9.8, which has a similar structure and subcellular localization in mammalian cells, also inhibits NF-kappaB-dependent gene expression . We propose that suppression of inflammatory responses by intracellular S . enterica serovar Typhimurium, and perhaps Shigella flexneri, contributes to bacterial colonization of host tissues and pathogenesis. Infect Immun, 2003 Jul, 71(7), 3927 - 36 Glutamine synthetase GlnA1 is essential for growth of Mycobacterium tuberculosis in human THP-1 macrophages and guinea pigs; Tullius MV et al.; To assess the role of glutamine synthetase (GS), an enzyme of central importance in nitrogen metabolism, in the pathogenicity of Mycobacterium tuberculosis, we constructed a glnA1 mutant via allelic exchange . The mutant had no detectable GS protein or GS activity and was auxotrophic for L-glutamine . In addition, the mutant was attenuated for intracellular growth in human THP-1 macrophages and avirulent in the highly susceptible guinea pig model of pulmonary tuberculosis . Based on growth rates of the mutant in the presence of various concentrations of L-glutamine, the effective concentration of L-glutamine in the M . tuberculosis phagosome of THP-1 cells was approximately 10% of the level assayed in the cytoplasm of these cells (4.5 mM), indicating that the M . tuberculosis phagosome is impermeable to even very small molecules in the macrophage cytoplasm . When complemented by the M . tuberculosis glnA1 gene, the mutant exhibited a wild-type phenotype in broth culture and in human macrophages, and it was virulent in guinea pigs . When complemented by the Salmonella enterica serovar Typhimurium glnA gene, the mutant had only 1% of the GS activity of the M . tuberculosis wild-type strain because of poor expression of the S . enterica serovar Typhimurium GS in the heterologous M . tuberculosis host . Nevertheless, the strain complemented with S . enterica serovar Typhimurium GS grew as well as the wild-type strain in broth culture and in human macrophages . This strain was virulent in guinea pigs, although somewhat less so than the wild-type . These studies demonstrate that glnA1 is essential for M . tuberculosis virulence. Infect Immun, 2003 Jul, 71(7), 3690 - 8 Selection of small-colony variants of Salmonella enterica serovar typhimurium in nonphagocytic eucaryotic cells; Cano DA et al.; Salmonella enterica strains are enteropathogenic bacteria that survive and proliferate within vacuolar compartments of epithelial and phagocytic cells . Recently, it has been reported that fibroblast cells are capable of restricting S . enterica serovar Typhimurium intracellular growth . Here, we show that prolonged residence of bacteria in the intracellular environment of fibroblasts results in the appearance of genetically stable small-colony variants (SCV) . A total of 103 SCV isolates, obtained from four independent infections, were subjected to phenotypic analysis . The following phenotypes were observed: (i) delta-aminolevulinic acid auxotrophy; (ii) requirement for acetate or succinate for growth in glucose minimal medium; (iii) auxotrophy for aromatic amino acids; and (iv) reduced growth rate under aerobic conditions not linked to nutrient auxotrophy . The exact mutations responsible for the SCV phenotype in three representative isolates were mapped in the lpd, hemL, and aroD genes, which code for dihydrolipoamide dehydrogenase, glutamate-1-semyaldehyde aminotransferase, and 3-dehydroquinate dehydratase, respectively . The lpd, hemL, and aroD mutants had intracellular persistence rates in fibroblasts that were 3 to 4 logs higher than that of the parental strain and decreased susceptibility to aminoglycoside antibiotics . All three of these SCV isolates were attenuated in the BALB/c murine typhoid model . Complementation with lpd(+), hem(+), and aroD(+) genes restored the levels of intracellular persistence and antibiotic susceptibility to levels of the wild-type strain . However, virulence was not exhibited by any of the complemented strains . Altogether, our data demonstrate that similar to what it has been reported for SCV isolates of other pathogens, S . enterica SCV display enhanced intracellular persistence in eucaryotic cells and are impaired in the ability to cause overt disease . In addition, they also suggest that S . enterica SCV may be favored in vivo. Dev Comp Immunol, 2003 Oct, 27(9), 823 - 34 CpG-induced immunomodulation and intracellular bacterial killing in a chicken macrophage cell line; Xie H et al.; The immunostimulatory properties of synthetic CpG oligodeoxynucleotides (ODNs) have been studied in various mammalian models including humans and mice . However, little was known about effects of CpG ODNs on immune responses of chickens, a common avian species with important economical value in the poultry industry . In the present study, two CpG ODNs, 2006 and 1826, which show immunomodulating properties for humans and mice were tested using a chicken macrophage cell line (HD11) . ODN 2006, which has been reported to be an optimal stimulatory sequence for humans, showed strong immunomodulatory effects on HD11 cells, whereas ODN 1826, a CpG sequence with optimal immunostimulatory effects on mice, had weak influences on HD11 cells . ODN 2006 also induced strong IL-6 and nitric oxide secretion by HD11 cells in both dose- and time-dependent manners . Intracellular killing of Salmonella enteritidis (SE) was also increased in ODN 2006-activated HD11 cells . Furthermore, HD11 cells had reduced proliferation and underwent apoptosis, which is contradictory to the effects of ODN 2006 on human and murine cells . N(G)-monomethyl L-arginine (L-NMMA), an iNOS inhibitor, inhibited apoptosis of HD11 cells induced by ODN 2006, suggesting that this effect was likely mediated through an iNOS-dependent pathway . These results indicate that the differences in the responses of chicken HD11 macrophage cells to CpG ODNs compared to those of mammalian macrophages are species-related, and the potential of CpG ODNs as immunomodulators in poultry needs to be further explored. J Hosp Infect, 2003 Jun, 54(2), 93 - 8 Detection of a nosocomial outbreak of salmonellosis may be delayed by application of a protocol for rejection of stool cultures; Bruins MJ et al.; In October 2001 an outbreak of Salmonella enterica serovar enteritidis phage-type 6 occurred in a hospital and a nursing home, both served by the same hospital kitchen . Five nursing home residents died during the outbreak . S . enteritidis was isolated from three of them . Of 231 stool samples from nursing home residents, hospital patients and employees, 82 were culture-positive . All symptomatic patients were treated with oral ciprofloxacin . Inspection of the kitchen showed that during preparation of the desserts implicated in causing the outbreak, temperatures were not measured and storage temperatures were too high . No left-over food samples were available for analysis . According to the 'four-day rule' in use in this hospital, the stool samples related to the first outbreak were not cultured for Salmonella spp., whereas culturing afterwards from both stored specimens and repeats, showed that some of these samples would have been positive for S . enteritidis . Thus without the application of stool culture rejection criteria the outbreak would have been detected one day earlier . With the four-day rule in effect, the outbreak might have been detected much later, if an unusually high number of nursing home residents with gastroenteritis had not been noticed by nursing home physicians . The rule was revised to prevent a possible delay in the future . As a result of this outbreak, the government has announced legislation forbidding the sale of Salmonella-contaminated eggs . An official ban on the use of raw eggs will be included in several hygiene codes. Poult Sci, 2003 Jun, 82(6), 1008 - 10 Molting and Salmonella enterica serovar enteritidis infection: the problem and some solutions; Holt PS; Induced molting is an important economic tool used by the egg industry to recycle an aging layer flock . It is estimated that approximately 70% of the flocks nationwide and almost 100% in California are molted annually . Considering that there are approximately 240 million hens in production in the U.S., a rough estimate of the numbers of hens molted every year would be between 144 and 168 million birds, a substantial number . There are many methods to induce molt, but feed removal until hens lose a specific weight is the most prevalent molt strategy in the U.S . However, experimental studies in our laboratory have shown that induced molting via feed removal depresses the immune system of hens and exacerbates a Salmonella enteritidis (SE) problem in a simulated flock situation . Molted hens excreted significantly higher SE numbers in the feces, had higher numbers of SE in internal organs, and exhibited more intestinal inflammation . Molted hens were 100- to 1,000-fold more susceptible to infection by SE and therefore more readily transmitted the organism to uninfected hens in neighboring cages . With the problems identified, solutions were sought, and several were successful in ameliorating the SE issue . Antibiotic therapy, vaccination, and use of low-energy, low-calcium diets to molt hens all dramatically decreased SE shedding during molt . All of the solutions provide the producer with many potential solutions to the SE food safety issue and still allow them to recycle their hens. Poult Sci, 2003 Jun, 82(6), 1003 - 7 The gastrointestinal tract ecology of Salmonella enteritidis colonization in molting hens; Ricke SC; There is an interaction between feed withdrawal induced-molting and foodborne Salmonella Enteritidis colonization and invasion in susceptible laying hens . Less is known about the ecology of the indigenous microflora and their response to feed removal, the response of S . Enteritidis to feed removal (virulence expression), and the interaction between the gastrointestinal tract microenvironment and S . Enteritidis . Because the crop is the first host environment encountered by S . Enteritidis after ingestion, it can influence the survival and virulence of S . Enteritidis . Feed withdrawal alters the microenvironment of the crop by causing alterations in the indigenous microbial population along with lactate and short-chain fatty acids (SCFA) concentrations and an increase in pH . This altered crop environment is accompanied by increased S . Enteritidis colonization of the crop and ceca along with invasion of the spleen and liver . The observation that crop composition influences the virulence of S . Enteritidis has important implications for understanding the gastrointestinal factors necessary for protection against S . Enteritidis infection . Consequently, an important aspect for minimizing S . Enteritidis colonization during molting is to maintain the crop microflora and their fermentative activities as similar as possible to that of crop microflora and fermentation activities of birds with fully active gastrointestinal microbial populations. Cell Microbiol, 2003 Jul, 5(7), 435 - 44 Characterization of mediators of microbial virulence and innate immunity using the Caenorhabditis elegans host-pathogen model; Alegado RA et al.; The soil-borne nematode, Caenorhabditis elegans, is emerging as a versatile model in which to study host-pathogen interactions . The worm model has shown to be particularly effective in elucidating both microbial and animal genes involved in toxin-mediated killing . In addition, recent work on worm infection by a variety of bacterial pathogens has shown that a number of virulence regulatory genes mediate worm susceptibility . Many of these regulatory genes, including the PhoP/Q two-component regulators in Salmonella and LasR in Pseudomonas aeruginosa, have also been implicated in mammalian models suggesting that findings in the worm model will be relevant to other systems . In keeping with this concept, experiments aimed at identifying host innate immunity genes have also implicated pathways that have been suggested to play a role in plants and animals, such as the p38 MAP kinase pathway . Despite rapid forward progress using this model, much work remains to be done including the design of more sensitive methods to find effector molecules and further characterization of the exact interaction between invading pathogens and C . elegans' cellular components. Trans Am Clin Climatol Assoc, 2003, 114, 191 - 201; discussion 201-2 The color of hamburger: slow steps toward the development of a science-based food safety system in the United States; Morris JG Jr; Concerns about food safety have played a key role in the emergence of the public health system in the United States . Unfortunately, the food safety regulatory system that was established in the early part of the 20th century in response to these concerns has not kept pace with our advancing scientific knowledge . In 1995, basic changes were made in the structure of the U.S . food safety regulatory structure, including implementation by USDA of the Pathogen Reduction: Hazard Analysis and Critical Control Point (HACCP) Systems; Final Rule for Meat and Poultry, from USDA's Food Safety and Inspection Service (FSIS); this was accompanied by creation of FoodNet, a sentinel surveillance system for active collection of foodborne disease surveillance data . The most recent FoodNet data show a 21% decline in the incidence of major bacterial foodborne diseases since implementation of the new regulations, a decrease paralleled by reductions in the frequency of contamination of meat and poultry with Salmonella . These data strongly support the public health importance of these regulatory changes . However, questions remain about the relative degree of responsibility of industry vs . the consumer in assuring safe food; the appropriateness of microbial standards for raw food products; and the directions that should be taken in the development of the "next generation" of food safety regulations. J Bacteriol, 2003 Jul, 185(13), 3983 - 8 The ATPase FliI can interact with the type III flagellar protein export apparatus in the absence of its regulator, FliH; Minamino T et al.; Salmonella FliI is the ATPase that drives flagellar protein export . It normally exists as a complex together with the regulatory protein FliH . A fliH null mutant was slightly motile, with overproduction of FliI resulting in substantial improvement of its motility . Mutations in the cytoplasmic domains of FlhA and FlhB, which are integral membrane components of the type III flagellar export apparatus, also resulted in substantially improved motility, even at normal FliI levels . Thus, FliH, though undoubtedly important, is not essential. Int J Food Microbiol, 2003 Aug 15, 85(1-2), 63 - 71 Application of a novel immunomagnetic separation-bacteriophage assay for the detection of Salmonella enteritidis and Escherichia coli O157:H7 in food; Favrin SJ et al.; Salmonella infection is the second most prevalent cause of foodborne illness in most developing countries . Meat, poultry, and dairy products are frequently implicated in outbreaks . The objective of this study was to apply a novel immunomagnetic separation (IMS)-bacteriophage assay to the detection of Salmonella enteritidis in artificially inoculated skimmed milk powder, chicken rinses, and ground beef . In all food types tested, the IMS-bacteriophage assay was able to detect an average of 3 CFU of S . enteritidis in 25 g or ml of food sample . Total assay time including pre-enrichment is about 20 h . The results indicate that the IMS-bacteriophage assay is a rapid and sensitive means of detecting S . enteritidis in these foods . The assay was successfully adapted to the detection of Escherichia coli O157:H7 and was able to detect E . coli in ground beef at the lowest inoculation level tested, 2 CFU/g . The assay was also adapted to the simultaneous detection of S . enteritidis and E . coli . The results indicate that the IMS-bacteriophage assay shows promise for the simultaneous detection of these pathogens, but further development work would be necessary to improve sensitivity and produce reliable results at low inoculation levels. Cent Afr J Med, 2001 Nov-Dec, 47(11-12), 254 - 7 Asymptomatic salmonellosis and drug susceptibility in the Buea District, Cameroon; Nkuo-Akenji TK et al.; OBJECTIVES: The objectives were to investigate the prevalence of asymptomatic Salmonella infections in Buea and determine the antibiotic susceptibility pattern of isolates cultured from carriers . DESIGN: This was a descriptive study . Subjects were randomly selected from the community . Stool samples or rectal swabs were collected after consent to participate in the study . These samples were cultured on standard media . Salmonella species isolated were tested for antibiotic sensitivity by the agar diffusion method . SETTING: The study was carried out in three localities of the Buea district of Cameroon namely Molyko, Great Soppo and Bolifamba . SUBJECTS: 156 participants aged three months to 47 years old who were not suffering from fever, gastroenteritis or other signs and symptoms were recruited . INTERVENTION: Carriers of Salmonella were referred to the medical doctor of the university of Buea Health Unit . MAIN OUTCOME MEASURES: Asymptomatic carriers could eventually form the basis of an effective epidemiological surveillance system in developing rational strategies to control Salmonella infections . RESULTS: Salmonella species were isolated in 62 (39.7%) subjects with the following distribution: eight (5.1%) S . typhi, 19 (12.2%) S . paratyphi and 35 (22.4%) S . typhimurium . No significant difference was observed between those who were infected with the different Salmonella species (p > 0.05) . The most effective antibiotic was ofloxacin while resistance to chloramphenicol was remarkable . S . typhimurium showed the highest resistance to all antibiotics tested . CONCLUSION: The population of Buea is at risk of acquiring Salmonella infections from asymptomatic individuals . An effective surveillance system to detect carriers and properly treat them is highly recommended. J Korean Med Sci, 2003 Jun, 18(3), 325 - 30 A virulent strain of Salmonella enterica serovar London isolated in infants with enteritis traced by active surveillance and molecular epidemiological study; Kim S et al.; A total of 74 isolates of Salmonella enterica serovar London were collected through the Laboratory-Based Diarrheal Diseases Surveillance in 2000-2001 . In order to characterize the isolates and investigate the source of the epidemic, we performed antimicrobial susceptibility tests and XbaI Pulsed-field gel electrophoresis (PFGE) of 44 Salmonella London isolates . Forty isolates were from feces of infants and four isolates were from adults aged 30, 52, 54, and 59 yr . Two subtypes were identified: a tetracycline-susceptible A 0 PFGE pattern and a tetracyclineresistant A 1 PFGE pattern . Interestingly, the isolates from all infants and one 30-yr-old adult were A 0 PFGE pattern and tetracycline-susceptible . Furthermore, the A 0 PFGE pattern strain was approximately 2 times more virulent than the A 1 PFGE pattern strain, according to the results of in vitro invasion assay using J774A.1 macrophage-like cells . These results indicate that the active surveillance with molecular epidemiological tools would be valuable for promptly finding new epidemic strains . Our results also suggested that the virulent Salmonella London strain might infect the infants through a common contaminated source. J Appl Microbiol, 2003, 95(1), 142 - 5 Reducing colonization of Salmonella Enteritidis in chicken by targeting outer membrane proteins; Khan MI et al.; AIMS: To evaluate the ability of Salmonella enterica ser . Enteritidis outer membrane proteins (OMPs) of 75.6 and 82.3 kDa to inhibit or reduce in vivo colonization of S . Enteritidis on intestinal mucosa in chickens . METHODS AND RESULTS: Nine-week-old specific-pathogen-free chickens were subcutaneously immunized with 75.6 or 82.3 kDa protein, and challenged with a virulent strain of S . Enteritidis . Chickens were killed, and portions of small intestine and caecum were removed at necropsy . The population of S . Enteritidis attached to chicken intestinal mucosa was determined . The population of S . Enteritidis recovered from the small intestine and caecum of chickens immunized with 75.6 or 82.3 kDa protein was significantly (P < 0.05) lower than that recovered from the control birds . CONCLUSIONS: Salmonella Enteritidis OMPs 75.6 kDa and 82.3 kDa were effective in reducing colonization of S . Enteritidis on intestinal mucosa in chickens . SIGNIFICANCE AND IMPACT OF THE STUDY: Salmonella Enteritidis OMPs 75.6 or 82.3 kDa could be used as potential vaccines to reduce S . Enteritidis colonization in chickens. Eur J Dermatol, 2003 May-Jun, 13(3), 297 - 8 Lipschütz genital ulceration: a rare manifestation of paratyphoid fever; Pelletier F et al.; In 1913, a distinctive clinical entity of acute genital ulcer occurring in an adolescent girl with a non-venereal infectious aetiology was described by Lipschutz . Since the initial description, several aetiologies have been discussed, and among them, paratyphoid fever is very uncommon . After her return from a trip, a 25-year-old girl developed high fever and diarrhoea . Examination of the vulva revealed a genital ulcer . The rest of the general examination was normal . Blood cultures identified Salmonella paratyphi A, and a diagnosis of Lipschutz's ulcer associated with paratyphoid fever was made . Bacteriaemia was then treated with antibiotics and the vulvar ulceration rapidly disappeared . Lipschutz described a distinctive clinical entity of acute genital ulcers occurring in adolescents . To our knowledge, we report herein the second case associated with proved paratyphoid fever . The authors thus recommend that typhoid or paratyphoid fever should be included in the differential diagnosis of genital ulcerations. Vaccine, 2003 Jul 4, 21(23), 3249 - 58 Salmonella DNA adenine methylase mutants elicit early and late onset protective immune responses in calves; Dueger EL et al.; Salmonellosis is an important disease of livestock and Salmonella contamination of livestock-derived food products and effluents pose a significant risk to human health . Salmonella vaccines currently available to prevent salmonellosis in cattle have limited efficacy . Here we evaluated a Salmonella enterica serovar Typhimurium vaccine strain lacking the DNA adenine methylase (Dam) for safety and efficacy in calves . Vaccination was safe in calves, and following challenge with virulent Typhimurium 4 weeks post-immunization, vaccinated animals exhibited significantly lower mortality, diarrhea, and rectal temperatures, as well as reduced colonization of gastrointestinal tract and visceral organs compared to non-vaccinated control animals . Additionally, early onset protection (competitive exclusion) in vaccinated neonatal calves was demonstrated by attenuated clinical disease (as measured by rectal temperatures and attitude scores) and reduced mortality when challenged with virulent Typhimurium 24h after immunization . Taken together, these data suggest that vaccination with Salmonella Dam mutant strains confer significant protection against Salmonella infections in cattle via both adaptive immunity and competitive exclusion mechanisms. J Food Prot, 2003 Jun, 66(6), 1071 - 3 Response of Salmonella and Escherichia coli O157:H7 to UV energy; Yaun BR et al.; To determine the efficacy of a UV light treatment at 253.7 nm (UVC light) on microbial growth, plates containing tryptic soy agar plus 50 ppm of nalidixic acid (TSAN) were inoculated with known concentrations of five-strain cocktails of Salmonella and Escherichia coli O157:H7 and subjected to different UVC treatments . The concentration of the cocktail inoculum was determined with TSAN prior to inoculation . Serial dilutions were carried out, and inoculation levels of 10(0) to 10(8) CFU/ ml were tested for each pathogen . Multiple replications of doses of UV light ranging from 1.5 to 30 mW/cm2 were applied to different cocktail concentrations, and doses of > 8.4 mW/cm2 resulted in a 5-log reduction of Escherichia coli O157:H7, while a 5-log reduction of Salmonella was observed with doses of > 14.5 mW/cm2 . Results for both organisms yielded sigmoidal inactivation curves . UVC light is effective in reducing microbial populations of pathogens on agar surfaces. J Food Prot, 2003 Jun, 66(6), 1025 - 9 Inactivation by ionizing radiation of Salmonella enteritidis, Salmonella infantis, and Vibrio parahaemolyticus in oysters (Crassostrea brasiliana); Jakabi M et al.; Irradiation is considered one of the most efficient technological processes for the reduction of microorganisms in food . It can be used to improve the safety of food products, and to extend their shelf lives . Oysters are considered one of the most important vehicles for pathogenic bacteria because of their feeding characteristics . The aim of this study was to evaluate the influence of a gamma radiation process on high levels of Salmonella Enteritidis, Salmonella Infantis, and Vibrio parahaemolyticus incorporated by oysters (Crassostrea brasiliana), as well as the effects of the process on the survival of the oysters and on their sensory attributes . The oysters were exposed to gamma radiation (60Co) in doses ranging from 0.5 to 3.0 kGy . A dose of 3.0 kGy was generally sufficient to reduce the level of Salmonella serotypes by 5 to 6 log10 units . A dose of 1.0 kGy was sufficient to produce a 6-log10 reduction in the level of V . parahaemolyticus . The highest irradiation dose did not kill the oysters or affect their sensory attributes . Hence, a dose of 3.0 kGy can be considered effective in inactivating Salmonella and V . parahaemolyticus in oysters without changing their odor, flavor, or appearance. J Food Prot, 2003 Jun, 66(6), 999 - 1006 Inhibition of Listeria monocytogenes in pH-adjusted pasteurized liquid whole egg; Schuman JD et al.; Although the transmission of L . monocytogenes to humans via pasteurized egg products has not been documented, L . monocytogenes and other Listeria species have been isolated from commercially broken raw liquid whole egg (LWE) in both the United States and Ireland . Recent Listeria thermal inactivation studies indicate that conventional minimal egg pasteurization processes would effect only a 2.1- to 2.7-order-of-magnitude inactivation of L . monocytogenes in LWE; thus, the margin of safety provided by conventional pasteurization processes is substantially smaller for L . monocytogenes than for Salmonella species (a 9-order-of-magnitude process) . The objective of this study was to evaluate the inhibitory effects of nisin on the survival and growth of L . monocytogenes in refrigerated and pH-adjusted (pH 6.6 versus pH 7.5) ultrapasteurized LWE and in a liquid model system . The addition of nisin (1,000 IU/ml) to pH-adjusted ultrapasteurized LWE reduced L . monocytogenes populations by 1.6 to > 3.3 log CFU/ml and delayed (pH 7.5) or prevented (pH 6.6) the growth of the pathogen for 8 to 12 weeks at 4 and 10 degrees C . Bioactive nisin was detected in LWE at both pH values for 12 weeks at 4 degrees C . In subsequent experiments, Listeria reductions of > 3.0 log CFU/ml were achieved within 24 h in both LWE and broth plus nisin (500 IU/ml) at pH 6.6 but not at pH 7.5, and antilisterial activity was enhanced when nisin was added as a solution rather than in dry form. Folia Microbiol (Praha), 2003, 48(2), 277 - 9 Spreading of Salmonella enteritidis in the cecum of chickens; Asheg AA et al.; Adhesion and colonization of high (2 x 10(8) CFU) and low doses (2 x 10(2) CFU) of Salmonella enteritidis (phage type 4) was determined in the ceca collected 6 h-4 weeks after inoculation (pi), of 1-d-old White Plymouth Rock orally-inoculated chickens . S . enteritidis was associated with the epithelial surface of the villi in the low-dose group 18 h-7 d pi, the penetration in the cecal lamina propria was observed on day 1 and 10 pi . In the high-dose group, adhesion and colonization was observed in all birds killed 6 h-14 d pi; penetration of the bacteria into the cecal lamina propria was seen 1-21 d pi . Large numbers of macrophage-like cells containing S . enteritidis were observed in the cecal lamina propria on days 3-21 pi . Colonization and migration by S . enteritidis in the intestinal tract of chickens was shown to be dose dependent. Folia Microbiol (Praha), 2003, 48(2), 257 - 60 Colicinogeny in local isolates of salmonellae and plasmid transfer studies; Elpek G et al.; Colicinogeny was determined in local isolates of S . typhimurium and S . enteritidis . Fourteen out of 35 S . typhimurium isolates of hospital origin were colicin producers whereas only one chicken isolate out of 82 S . enteritidis isolates of various origin (human, chicken or egg) produced colicin . A colicin producing, cephalothin (Cpt)- and piperacillin (Prl)-resistant local isolate of Salmonella havana (H32) harbored 4 plasmids of 54.0, 28.4, 2.7 and 1.9 kb . Upon curing its plasmids, the strain lost the ability to produce colicin and resistance to antibiotics and no longer expressed smooth lipopolysaccharide (LPS) . The outer membrane protein (OMP) of 34.6 kDa was also lost . Using nalidixic acid (Nal)-resistant mutant of the cured strain in conjugation experiments, 10 out of 27 transconjugants were found to be resistant to Nal and Prl, 10 were resistant to Nal and Cpt and 7 showed Nal, Prl and Cpt resistance . Cpt and Prl resistance were determined by 54.0 and 28.4 kb plasmids, respectively . There was no direct correlation between plasmid contents and colicinogeny, LPS and OMP profiles. Biotechnol Bioeng, 2003 Aug 20, 83(4), 465 - 73 Effect of heat on phycoerythrin fluorescence: Influence of thermal exposure on the fluorescence emission of R-phycoerythrin; Vaidya S et al.; The goal of this work was to measure and model the effect of thermal exposure on the fluorescence emission of R-phycoerythrin (R-PE) . The long-term objective of our work is to assess the feasibility of encapsulating R-PE for use as the critical component of a time-temperature integrator (TTI) for ascertaining the degree of inactivation of food pathogens such as Salmonella . In this article we present a study to measure and model the thermally induced fluorescence emission decay of R-PE in several isothermal experiments . We used the isothermal data to determine the kinetic parameters, based on a general n(th) order reaction, and evaluated the utility of the resulting model by using it to predict R-PE fluorescence emission decay for several nonisothermal experiments based on published USDA safe harbor guidelines for cooked beef products . The transient experiments were conducted over the same temperature range used in the isothermal study . Very good agreement was obtained between theory and experiment at temperatures of 62.8 degrees C and above, although the model slightly underpredicted the extent of fluorescence emission decay at 60 degrees C . Our results indicate that R-PE fluorescence emission decay kinetics is well behaved and that the protein is a strong candidate for use as a time-temperature integrator . FEMS Microbiol Lett, 2003 Jun 6, 223(1), 53 - 60 Tetratricopeptide-like repeats in type-III-secretion chaperones and regulators; Pallen MJ et al.; Efficient type-III secretion depends on cytosolic molecular chaperones, which bind specifically to the translocators and effectors . In the past there has been a tendency to shoe-horn all type-III-secretion chaperones into a single structural and functional class . However, we have shown that the LcrH/SycD-like chaperones consist of three central tetratricopeptide-like repeats that are predicted to fold into an all-alpha-helical array that is quite distinct from the known structure of the SycE class of chaperones . Furthermore, we predict that this array creates a peptide-binding groove that is utterly different from the helix-binding groove in SycE . We present a homology model of LcrH/SycD that is consistent with existing mutagenesis data . We also report the existence of tetratricopeptide-like repeats in regulators of type-III secretion, such as HilA from Salmonella enterica and HrpB from Ralstonia solanacearum . The discovery of tetratricopeptide-like repeats in type-III-secretion regulators and chaperones provides a new conceptual framework for structural and mutagenesis studies and signals a potential unification of prokaryotic and eukaryotic chaperone biology. FEMS Microbiol Lett, 2003 Jun 6, 223(1), 7 - 14 Identification, cloning and characterization of rfaE of Actinobacillus pleuropneumoniae serotype 1, a gene involved in lipopolysaccharide inner-core biosynthesis; Provost M et al.; Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia and its lipopolysaccharides (LPS) have been identified as important adhesins involved in adherence to host cells . To better understand the role of LPS core in the virulence of this organism, the aim of the present study was to identify and clone genes involved in LPS core biosynthesis by complementation with Salmonella enterica serovar Typhimurium mutants (rfaC, rfaD, rfaE and rfaF) . Complementation with an A . pleuropneumoniae 4074 genomic library was successful with Salmonella mutant SL1102 . This Salmonella deep-rough LPS mutant is defective for the rfaE gene, which is an ADP-heptose synthase . Novobiocin was used to select transformants that had the smooth-LPS type, since Salmonella strains with wild-type smooth-LPS are less permeable, therefore more resistant to hydrophobic antibiotics like novobiocin . We obtained a clone that was able to restore the wild-type smooth-LPS Salmonella phenotype after complementation . The wild-type phenotype was confirmed using phage (Felix-O, P22c.2 and Ffm) susceptibility and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) . One of the open reading frames contained in the 3.3-kb insert in the plasmid encoded a 475-amino-acid protein with 71% identity and 85% similarity to the RfaE protein of S . enterica . We then attempted to generate an A . pleuropneumoniae rfaE mutant by gene replacement . The rfaE gene seems essential in A . pleuropneumoniae viability as we were unable to isolate a heptose-less knockout mutant. Vaccine, 2003 Jun 20, 21(21-22), 3051 - 7 Oral immunisation with live aroA attenuated Salmonella enterica serovar Typhimurium expressing the Yersinia pestis V antigen protects mice against plague; Garmory HS et al.; Bubonic and pneumonic plague are caused by the bacterium Yersinia pestis . The V antigen of Y . pestis is a protective antigen against plague . In this study, an aroA attenuated strain of Salmonella enterica serovar Typhimurium (SL3261) has been used to deliver the Y . pestis V antigen as a candidate oral plague vaccine . SL3261 was transformed with the expression plasmid pTrc-LcrV, containing the lcrV gene encoding V antigen . Immunoblot analysis showed V antigen expression in SL3261 in vitro and intragastric immunisation of mice with the recombinant Salmonella resulted in the induction of V antigen-specific serum antibody responses and afforded protection against Y . pestis challenge . However, the antibody responses induced by the recombinant Salmonella did not correlate with the protection afforded, indicating that immune responses other than antibody may play a role in the protection afforded against plague by this candidate vaccine. Vaccine, 2003 Jun 20, 21(21-22), 2933 - 47 Long-term safety analysis of preventive HIV-1 vaccines evaluated in AIDS vaccine evaluation group NIAID-sponsored Phase I and II clinical trials; Gilbert PB et al.; This report evaluates long-term safety data from 3189 human immunodeficiency virus type 1 (HIV-1) uninfected, healthy volunteers who were enrolled into 51 National Institute of Allergy and Infectious Diseases (NIAID)-sponsored Phase I and II multicentred, randomized, double-blind trials of recombinant HIV-1 subunit vaccines (23 studies), synthetic peptide vaccines (7 studies), live vaccinia-vector recombinant envelope vaccines (7 studies), canarypox vector recombinant vaccines (13 studies), a DNA vaccine (1 study), and a Salmonella-vector vaccine (1 study) . During the 12,340 person-years of follow-up, participants were monitored for adverse events including immune dysfunction/autoimmunity, anaphylaxis, cancer, death, and vaccine allergy . The analysis provides evidence that a preparation of a C4-V3 polypeptide vaccine emulsified in incomplete Freund's caused serious toxicity, but otherwise no safety problems considered serious were identified for any of the vaccines and adjuvants studied . These data serve to solidify the growing safety base of current vaccine technologies utilized in candidate vaccines for HIV-1 infection. Vaccine, 2003 Jun 20, 21(21-22), 2758 - 60 Immunogenicity of a new Salmonella Typhi Vi polysaccharide vaccine--vax-TyVi--in Cuban school children and teenagers; Azze RF et al.; A randomized, controlled, double blind study was carried out in Cuban children and teenagers aged 9-13 years to evaluate the immunogenicity of vax-TyVi-Salmonella Typhi Vi polysaccharide vaccine-with respect control vaccines . Serum samples were taken before and 21 days after the immunization, and ELISA was used for the determination of antibodies to Vi polysaccharide . Subjects who received vax-TyVi and TYPHIM Vi (Pasteur-Merieux) showed seroconversion rates of 85.61 and 78.36%, respectively . The geometric mean titer (GMT) values for Vi antibodies induced after vaccination were 6.27 microg/ml (5.40-7.38 microg/ml) and 5.97 microg/ml (5.01-7.10 microg/ml), respectively . In contrast, subjects receiving the tetanus toxoid vaccine showed 0% seroconversion. Sci Total Environ, 2003 Jun 20, 309(1-3), 35 - 46 Assessment of occupational health hazards in scrap-tire shredding facilities; Chien YC et al.; Occupational hygiene conditions in scrap-tire shredding facilities were assessed to identify potential health risk factors for workers and provide a basis for developing future control measures . Specifically, noise, volatile organics and particulate levels were measured at two plants . Particulate/dust levels were measured via filter collection, and were analyzed gravimetrically . Sound pressure levels were measured and their spectral properties analyzed . Moreover, the major chemical species in the samples were identified using GC/MS . Finally, the mutagenic activity associated with the airborne particulates was assessed using a typical Ames test applied to Salmonella strains TA98 and TA100, with or without bio-activation . The noise levels were steady and high throughout the facilities, ranging from 85 to approximately 100 dBA . The octave band spectrum analysis reveals pattern similarity among the different areas . Levels of volatile organics were not significant, but a few mutagens/carcinogens, such as styrene, benzothiazole, phthalate ester and naphthalene were identified . Total particulate levels ranged from 0.43 to 6.54 mg/m(3), while respirable particulates were in the range 0.23-1.25 mg/m(3) . Ames testing revealed indirect mutagenicity on strain TA98, indicating possible effects of frame-shift type mutagens . Chemical analysis of airborne particulates confirmed the presence of amines, aniline, quinoline, amides and benzothiazole, which are potentially convertible to frame-shift type mutagenic nitrosoamines . Noise appears to be an occupational hazard for workers at scrap-tire shredding facilities, but the risk associated with the mutagenic/carcinogenic property of particulates requires further confirmation. Infect Genet Evol, 2002 Oct, 2(1), 39 - 45 Salmonella typhi, the causative agent of typhoid fever, is approximately 50,000 years old; Kidgell C et al.; A global collection of 26 isolates of Salmonella typhi was investigated by sequencing a total of 3336 bp in seven housekeeping genes . Only three polymorphic sites were found and the isolates fell into four sequence types . These results show that S . typhi is a recent clone whose last common ancestor existed so recently that multiple mutations have not yet accumulated . Based on molecular clock rates for the accumulation of synonymous polymorphisms, we estimate that the last common ancestor of S . typhi existed 15,000-150,000 years ago, during the human hunter-gatherer phase and prior to the development of agriculture and the domestication of animals. Infect Genet Evol, 2002 Dec, 2(2), 107 - 10 Detection of Salmonella typhi by polymerase chain reaction: implications in diagnosis of typhoid fever; Kumar A et al.; The present study was conducted to detect Salmonella typhi by polymerase chain reaction (PCR) in a clinical setting . A group of 40 clinically suspected cases of typhoid fever, lasting for about 3-11 days, with or without chills and rigors and hepatosplenomegaly were selected . Of these, 20 were culture positive and the remaining 20 were found to be negative by conventional blood culture technique . Primary PCR was followed by nested PCR using two sets of primers corresponding to flagellar gene of S . typhi strain . Two bands of about 458 and 343 bp were detected in 20 blood culture positive cases and 12 of the 20 culture negative ones . In the simulated group of samples, no amplification was detected . Our results suggest that PCR-based diagnosis is particularly useful for all clinically suspected cases of typhoid fever . The sensitivity of PCR and its potential use in routine diagnosis and epidemiological studies of typhoid fever can be exploited to complement studies by including bone marrow culture, faeces and bile samples. J Clin Microbiol, 2003 Jun, 41(6), 2395 - 400 Several Salmonella enterica subsp . enterica serotype 4,5,12:i:- phage types isolated from swine samples originate from serotype typhimurium DT U302; de la Torre E et al.; Pulsed-field gel electrophoresis, plasmid profiling, and phage typing were used to characterize and determine possible genetic relationships between 48 Salmonella enterica subsp . enterica isolates of pig origin collected in Catalonia, Spain, from 1998 to 2000 . The strains were grouped into 23 multidrug-resistant fljB-lacking S . enterica serovar 4,5,12:i:- isolates, 24 S . enterica serovar Typhimurium isolates, and 1 S . enterica serovar 4,5,12:-:- isolate . After combining the XbaI and BlnI macrorestriction profiles (XB profile), we observed 29 distinct subtypes which were grouped into seven main patterns . All 23 of the 4,5,12:i:- serovar strains and 10 serovar Typhimurium isolates were found to have pattern AR, and similarities of >78% were detected among the subtypes . Three of the serovar Typhimurium DT U302 strains (strains T3, T4, and T8) were included in the same 4,5,12:i:- serovar cluster and shared a plasmid profile (profile I) and a pattern of multidrug resistance (resistance to ampicillin, chloramphenicol, streptomycin, sulfonamide, tetracycline, gentamicin, and trimethoprim-sulfamethoxazole) commonly found in monophasic isolates . This led us to the conclusion that strains of the S . enterica 4,5,12:i:- serovar might have originated from an S . enterica serovar Typhimurium DT U302 strain. J Clin Microbiol, 2003 Jun, 41(6), 2341 - 7 Distribution of the secondary type III secretion system locus found in enterohemorrhagic Escherichia coli O157:H7 isolates among Shiga toxin-producing E . coli strains; Makino S et al.; The ability of the complete genome sequence of enterohemorrhagic Escherichia coli O157 led to the identification of a 17-kb chromosomal region which contained a type III secretion system gene cluster at min 64.5 . This locus contains open reading frames whose amino acid sequences show high degrees of similarity with those of proteins that make up the type III secretion apparatus, which is encoded by the inv-spa-prg locus on a Salmonella SPI-1 pathogenicity island . This locus was designated ETT2 (E . coli type III secretion 2) and consisted of the epr, epa, and eiv genes . ETT2 was found in enteropathogenic E . coli strains and also in some non-O157 Shiga toxin-producing E . coli (STEC) strains, but most of them contained a truncated portion of ETT2 . Most O157 isolates had a complete collection of toxin-encoding genes eae and hlyA and the ETT2 locus, while most O26 strains had toxin-encoding genes eae and hlyA genes but an incomplete ETT2 locus . Thus, an intact copy of ETT2 might mark a pathogenic distinction for particular STEC strains . Therefore, the presence of the ETT2 locus can be used for identification of truly pathogenic STEC strains and for molecular fingerprinting of the epidemic strains in humans and animals. Trop Med Int Health, 2003 Jun, 8(6), 575 - 8 Prevalence of typhoid fever in febrile patients with symptoms clinically compatible with typhoid fever in Cameroon; Nsutebu EF et al.; Typhoid fever is difficult to differentiate from other causes of infection such as malaria because their signs and symptoms often overlap . There has been an unprecedented increase in the number of typhoid fever cases diagnosed in Cameroon . Febrile patients are often treated for malaria and typhoid fever simultaneously . This cross-sectional study was carried out to determine the prevalence of typhoid fever in 200 consecutive patients with fever and symptoms clinically compatible with typhoid fever to verify recent estimates of a high prevalence of typhoid fever in Cameroon . Patients were enrolled in three of the 10 provinces of Cameroon . Blood culture, thick and thin blood smears and Widal tests using acute sera were performed in all cases; stool culture for 120 patients . Typhoid fever was confirmed in only 2.5% as evidenced either by culture (four cases) or high salmonella antibody titres (one case); malaria was diagnosed in 94 (47%) patients . Typhoid fever is not as endemic in Cameroon as recently feared. Ceska Slov Farm, 2003 May, 52(3), 141 - 7 {Effect of disinfectants on surface hydrophobicity and mobility in Salmonella enterica serovar Typhimurium DT104}; Majtanova L et al.; The paper evaluated antibacterial efficacy of 12 disinfectants on the basis of quaternary ammonium compounds (KAZ) on the isolates of Salmonella enterica serovar Typhimurium of the definitive phage type 104 (DT104) . One isolate--5551/99--represented the multiresistant phenotype, resistant to ampicillin (A), chloramphenicol (C), streptomycin (S), and tetracycline (T) . The second isolate--577/99--was sensitive to all antibiotics tested . The present study further examined the capability of sub-MIC concentrations of disinfectants to intervene into surface hydrophobicity and motility of the strains tested . The results showed that all disinfectants under study exhibited high antibacterial activity . It is of interest that the isolate resistant to antibiotics was more sensitive to disinfectants in comparison with the isolate resistant to antibiotics . The most effective substances against strain 5551/99 (R-type) were Sokrena, Triquart, Hexaquart plus, ID213, and Microbac forte, and those most effective against strain 577/99 (S-type) were Benzalkonium chloride and Hexaquart plus (MIC 0.09-0.19 microliter/ml) . Surface hydrophobicity of both tested strains after the action of sub-MIC (1/16, 1/8, 1/4 of MIC) of disinfectants was not influenced in a more marked way . In the case of strain 5551/99, the highest percentage of inhibition of adherence to xylene, to 69.5% versus the control, was produced by 1/4 of MIC of the substance Triquart and, in the whole concentration range, by the substance Microbac forte . After the action of most substances to strain 577/99, stimulation of adherence took place . Only substance ID213 induced inhibition of adherence in the whole concentration range . The salt-aggregative capabilities of both strains were not influenced in a more marked way . The only exceptions were the action of 1/4 of MIC of the substances Cetrimid, Sokrena, ID212, Forten, and 1/8 of MIC of Hexaquart S on strain 577/99, where a decrease in hydrophobicity was observed . A moderate inhibition of motility was found after the action of 1/4 of MIC of Benzalkonium chloride (to 87.5%) and A.D.L . 007 (to 85.2%) on strain 5551/99 . In the case of sensitive isolate 577/99, the most markedly manifested inhibition effect was that of Sokrena within the whole concentration range and that of 1/4 of MIC ID213 . The results can be used in the selection of a suitable disinfectant for decontamination of solid surfaces . The effect of substances under study on surface hydrophobicity and motility of the important, food-transferred pathogen in the sense of inhibition or stimulation points out to intervention into its pathogenic potential. Appl Environ Microbiol, 2003 Jun, 69(6), 3456 - 61 Evaluation of DNA extraction methods for use in combination with SYBR green I real-time PCR to detect Salmonella enterica serotype enteritidis in poultry; De Medici D et al.; The objective of this study was to develop a rapid, reproducible, and robust method for detecting Salmonella enterica serotype Enteritidis in poultry samples . First, for the extraction and purification of DNA from the preenrichment culture, four methods (boiling, alkaline lysis, Nucleospin, and Dynabeads DNA Direct System I) were compared . The most effective method was then combined with a real-time PCR method based on the double-stranded DNA binding dye SYBR Green I used with the ABI Prism 7700 system . The specificity of the reaction was determined by the melting temperature (T(m)) of the amplicon obtained . The experiments were conducted both on samples of chicken experimentally contaminated with serotype Enteritidis and on commercially available poultry samples, which were also used for comparisons with the standard cultural method (i.e., ISO 6579/2001) . The results of comparisons among the four DNA extraction methods showed significant differences except for the results from the boiling and Nucleospin methods (the two methods that produced the lowest threshold cycles) . Boiling was selected as the preferred extraction method because it is the simplest and most rapid . This method was then combined with SYBR Green I real-time PCR, using primers SEFA-1 and SEFA-2 . The specificity of the reaction was confirmed by the T(m), which was consistently specific for the amplicon obtained; the mean peak T(m) obtained with curves specific for serotype Enteritidis was 82.56 +/- 0.22 degrees C . The standard curve constructed using the mean threshold cycle and various concentrations of serotype Enteritidis (ranging from 10(3) to 10(8) CFU/ml) showed good linearity (R(2) = 0.9767) and a sensitivity limit of less than 10(3) CFU/ml . The results of this study demonstrate that the SYBR Green I real-time PCR constitutes an effective and easy-to-perform method for detecting serotype Enteritidis in poultry samples. Microbes Infect, 2003 Jun, 5(7), 561 - 70 SseA is required for translocation of Salmonella pathogenicity island-2 effectors into host cells; Coombes BK et al.; The Salmonella pathogenicity island-2 (SPI2) is a virulence locus on the bacterial chromosome required for intracellular proliferation and systemic infection in mice . Cell culture models and a murine model of systemic infection were used to address the role of an uncharacterized SPI2 open reading frame, designated as sseA, in Salmonella virulence . A Salmonella strain with an unmarked internal deletion of sseA displayed a phenotype that was similar to an SPI2-encoded type III secretion system apparatus mutant . Moreover, SseA was required for survival and replication within epithelial cells and macrophages . Murine infection studies confirmed that the DeltasseA strain was severely attenuated for virulence . Using immunofluorescence microscopy, the virulence defect in the DeltasseA strain was attributed to an inability to translocate SPI2 effector proteins into host cells . These data demonstrate that SseA is essential for SPI2-mediated translocation of effector proteins. Mol Microbiol, 2003 Jun, 48(5), 1357 - 76 The use of flow cytometry to detect expression of subunits encoded by 11 Salmonella enterica serotype Typhimurium fimbrial operons; Humphries AD et al.; The Salmonella enterica serotype Typhimurium (S . Typhimurium) genome contains 13 putative fimbrial operons termed agf (csg), fim, pef, lpf, bcf, saf, stb, stc, std, stf, sth, sti and stj . Evidence for in vitro expression of fimbrial proteins encoded by these operons is currently only available for agf, fim and pef . We raised antisera against putative major fimbrial subunits of S . Typhimurium, including AgfA, FimA, PefA, LpfA, BcfA, StbA, StcA, StdA, StfA, SthA and StiA . Elaboration of StcA on the bacterial surface could be detected by flow cytometry and immunoelectron microscopy after expression of the cloned stcABCD operon from a heterologous T7 promoter in Escherichia coli . To study the expression of fimbrial antigens in S . Typhimurium by flow cytometry, we constructed strains carrying deletions of agfAB, pefBACDI, lpfABCDE, bcfABCDEFG, stbABCD, stcABC, stdAB, stfACDEFG, sthABCDE or stiABCDE . Using these deletion mutants for gating, expression of fimbrial antigens was measured by flow cytometry in cultures grown in vitro or in samples recovered 8 h after infection of bovine ligated ileal loops with S . Typhimurium . FimA was the only fimbrial antigen expressed by S . Typhimurium after static growth in Luria-Bertani (LB) broth . Injection of static LB broth cultures of S . Typhimurium into bovine ligated ileal loops resulted in the expression of BcfA, FimA, LpfA, PefA, StbA, StcA, StdA, StfA and StiA . These data show that in vivo growth conditions drastically alter the repertoire of fimbrial antigens expressed in S . Typhimurium. Int J Immunopathol Pharmacol, 1999 May, 12(2), 89 - 96 Virulence factors of salmonella ser . enteritidis strains isolated in Italy from food-borne outbreaks; Zagaglia C et al.; Twelve Salmonella ser . Enteritidis strains phage type 4 isolated in Italy from different food-borne outbreaks were characterized for the expression of different virulence traits, for antibiotic resistance, and for plasmid DNA profile . All the twelve S . Enteritidis strains were able to invade and multiply within HeLa cell monolayers, even if at a lower efficiency if compared to an invasive Shigella flexneri strain . The strains were not hemolytic and produced only a moderate-level cytotoxic effect on HeLa cell monolayers . Moreover, all the strains examined produced mannose-sensitive hemagglutination with chicken erythrocytes but were not able to adhere to tissue culture cells . The strains did not produce the hydroxamate-type siderophore aerobactin or the specific ferric-aerobactin receptor . The S . Enteritidis strains were resistant only to spectinomycin, and eleven strains harbored a 38 MDa non-conjugative plasmid, while one strain harbored a 64 MDa conjugative plasmid which carried a colicinogenic activity-encoding locus . The uniformity of antibiotic resistance pattern, of the plasmid DNA content, and of the virulence factors produced indicated that the S . Enteritidis clinical isolates examined are clonally-related. Int J Food Microbiol, 2003 Jul 15, 84(1), 87 - 92 Antimicrobial-resistant Salmonella serovars isolated from imported foods; Zhao S et al.; A total of 187 Salmonella isolates representing 82 serotypes recovered from 4072 imported foods in the year 2000 by the U.S . Food and Drug Administration field laboratories were tested for their susceptibility to 17 antimicrobials of human and veterinary importance . Fifteen (8%) isolates were resistant to at least one antimicrobial, and five (2.7%) were resistant to three or more antimicrobials . Most of the isolates (n=9) exhibited resistance to tetracycline . Four isolates from catfish or tilapia from Taiwan or Thailand also demonstrated resistance to nalidixic acid . These nalidixic acid-resistant Salmonella isolates possessed a point mutation at the Ser83 or Asp87 position in DNA gryase, resulting in amino acid substitutions to phenylalanine, tyrosine, or asparagine . One Salmonella Derby isolated from frozen anchovies imported from Cambodia was resistant to six antimicrobials including ampicillin, amoxicillin/clavulanic acid, chloramphenicol, sulfamethoxazole, tetracycline, and trimethoprim/sulfamethoxazole . Of seven isolates displaying resistance to sulfonamides, only one S . Derby and one Salmonella Agona contained class 1 integrons that were further shown to possess the aadA and pse-1 genes conferring resistance to streptomycin and ampicillin, respectively . This study indicates that antimicrobial-resistant Salmonella are present in imported foods, primarily of seafood origin, and stresses the need for continued surveillance of foodborne zoonotic bacterial pathogens from imported foods entering the United States. Int J Food Microbiol, 2003 Jul 25, 84(2), 217 - 24 Simultaneous detection of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella strains by real-time PCR; Bhagwat AA; A protocol enabling simultaneous detection of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella strains was devised and evaluated using artificially contaminated fresh produce . Association of Official Analytical Chemists (AOAC)-approved polymerase chain reaction (PCR) detection methods for three human pathogens were modified to enable simultaneous and real-time detection with high throughput capability . The method includes a melting-curve analysis of PCR products, which serves as confirmatory test . The modified protocol successfully detected all three pathogens when fresh produce was washed with artificially contaminated water containing E . coli O157:H7 and S . typhimurium down to the predicted level of 1 to 10 cells/ml and L . monocytogenes at 1000 cells/ml . The ability to monitor several pathogens simultaneously will save time and increase our ability to assure food safety. Int Immunopharmacol, 2003 Jun, 3(6), 825 - 34 Defense mechanisms of IFN-gamma and LPS-primed murine microglia against Acanthamoeba castellanii infection; Benedetto N et al.; In the central nervous system (CNS), cytokine-primed microglia play a central role in host's defense against Acanthamoeba castellanii infection . In this study, the effect of recombinant interferon (rIFN)-gamma and Salmonella enterica serovar enteritidis lipopolysaccharide (LPS), both inflammatory stimuli, on A . castellanii infection in murine microglia was examined . Priming of microglia with rIFN-gamma and LPS synergistically triggered, in a dose-dependent manner, amebastatic activity in these cells . More than 52%, 88% or 95% of this function was then abrogated by anti-IL-1beta (but not anti-IL-1alpha), IL-6 or TNF-alpha neutralizing antibodies, suggesting that these endogenously produced cytokines may participate in the antimicrobial capacity . Consistent with these findings, the priming of microglia with rIFN-gamma and LPS elicited the release of proinflammatory interleukin (IL)-1alpha, IL-1beta, IL-6 and tumor necrosis factor (TNF)-alpha . Since L-canavanine affected amebastatic activity only during the priming process but not during the infection process, NO-dependent pathway appears to be not the sole antiparasitic mechanism involved in this function . These data suggest that rIFN-gamma and LPS, likely through a proinflammatory network, up-regulate the release of IL-beta, IL-6 and TNF-alpha, which could trigger antimicrobial activity against A . castellanii infection in the brain. Eur J Immunol, 2003 Jun, 33(6), 1461 - 4 The role of interleukin-12 in human infectious diseases: only a faint signature; Fieschi C et al.; IL-12 is the signature IFN-gamma-inducing cytokine and, as such, is thought to be crucial for protective immunity against intracellular microorganisms . This concept is supported by results from experimental infections of knockout mice lacking IL-12 or the IL-12 receptor . The description of human patients with inherited IL-12 or IL-12-receptor deficiency challenges this view . Indeed, in natural conditions of infection and immunity - the hallmark of the human model - IL-12 was found to be redundant in defense against intracellular microorganisms other than Mycobacteria and Salmonella . More surprisingly, IL-12 was recently found to be redundant even in defense against primary intection by Mycobacteria and Salmonella in many patients, and against secondary infection by Mycobacteria but not Salmonella in most patients. Cell Biol Toxicol, 2003 Apr, 19(2), 83 - 93 Influence of peracetic acid on adhesion/invasion of Salmonella enterica serotype typhimurium LT2; Jolivet-Gougeon A et al.; The influence of peracetic acid (PAA) disinfectant on Salmonella enterica serotype Typhimurium LT2 in sewage effluent was examined by studying its ability to adhere to and invade HeLa cells in vitro . Although the disinfectant produced a decrease of about 5 log units, the bacteria kept their adhesive and invasive abilities . Scanning microscopic observations of the PAA-treated bacteria revealed that PAA caused a loss of external microfilaments and an alteration of membrane structure . Nevertheless, electron-microscopic observations showed that PAA-treated bacteria were still able to adhere to and invade HeLa cells despite the fact that the bacteria seemed to have undergone some structural modifications . With confocal microscopy, the use of anti-actin antibody showed that the contact between the bacteria (with or without PAA treatment) and the HeLa cells activated actinopolymerization of the HeLa cell cytoskeleton. J Bacteriol, 2003 Jun, 185(12), 3624 - 35 Variation between pathogenic serovars within Salmonella pathogenicity islands; Amavisit P et al.; Although four of the five Salmonella pathogenicity islands (SPIs) have been characterized in detail for Salmonella enterica serovar Typhimurium, and the fifth has been characterized for Salmonella enterica serovar Dublin, there have been limited studies to examine them in detail in a range of pathogenic serovars of S . enterica . The aim of this study was to examine these regions, shown to be crucial in virulence, in pathogenic serovars to identify any major deletions or insertions that may explain variation in virulence and provide further understanding of the elements involved in the evolution of these regions . Multiple strains of each of the 13 serovars were compared by Southern blot hybridization using a series of probes that together encompassed the full length of all five SPIs . With the exception of serovar Typhimurium, all strains of the same serovar were identical in all five SPIs . Those serovars that differed from serovar Typhimurium in SPI-1 to SPI-4 and from serovar Dublin in SPI-5 were examined in more detail in the variant regions by PCR, and restriction endonuclease digestion and/or DNA sequencing . While most variation in hybridization patterns was attributable to loss or gain of single restriction endonuclease cleavage sites, three regions, in SPI-1, SPI-3, and SPI-5, had differences due to major insertions or deletions . In SPI-1 the avrA gene was replaced by a 200-base fragment in three serovars, as reported previously . In SPI-5, two serovars had acquired an insertion with similarity to the pagJ and pagK genes between pipC and pipD . In SPI-3 the genes sugR and rhuM were deleted in most serovars and in some were replaced by sequences that were very similar to either the Escherichia coli fimbrial operon, flanked by two distinct insertion sequence elements, or to the E . coli retron phage PhiR73 . The distribution of these differences suggests that there have been a number of relatively recent horizontal transfers of genes into S . enterica and that in some cases the same event has occurred in multiple lineages of S . enterica . Thus, it seems that insertion sequences and retron phages are likely to be involved in continuing evolution of the pathogenicity islands of pathogenic Salmonella serovars. J Bacteriol, 2003 Jun, 185(12), 3567 - 74 Flagellar phase variation in Salmonella enterica is mediated by a posttranscriptional control mechanism; Bonifield HR et al.; Salmonella enterica has two antigenically distinct flagellin genes, fliC and fljB, that are alternatively expressed . The fljA gene is cotranscribed with fljB and encodes a protein that has been characterized as a transcriptional repressor of the unlinked fliC gene when FljB is expressed . In this study we report genetic evidence that FljA prevents the production of FliC protein through an interaction with the 5'-untranslated region of the fliC mRNA transcript . Studies with operon and gene fusions, Western analyses, and T(2) RNase protection assays were performed for strains with the fljBA promoter locked in either the on or the off orientation . beta-Galactosidase assays of fliC transcriptional and translational fusions to the lac operon demonstrated that while FljA inhibits fliC transcription fivefold in the fljBA(ON) orientation, it has a 200-fold effect on both fliC transcription and translation, indicating that the FljA inhibitor might act at both the transcriptional and translational level . T(2) RNase protection assays also demonstrated a fivefold decrease in fliC transcript levels for cells locked in the fljBA(ON) orientation compared to those in the fljBA(OFF) orientation, and an eightfold decrease in FliC protein levels was observed by Western analysis . This reduction in FliC protein levels is greater than the decrease observed for the transcript . These results are consistent with a new model whereby FljA inhibits FliC expression by an attenuation or translational control mechanism. J Bacteriol, 2003 Jun, 185(12), 3508 - 14 PhoP-responsive expression of the Salmonella enterica serovar typhimurium slyA gene; Norte VA et al.; The SlyA protein of Salmonella enterica serovar Typhimurium is a member of the MarR family of transcription regulators and is required for virulence and survival in professional macrophages . Isolated SlyA protein was able to bind a specific DNA target without posttranslational modification . This suggested that SlyA might not be activated by directly sensing an external signal but rather that the intracellular concentration of SlyA is enhanced in appropriate environments through the action of other transcription factors . Analysis of slyA transcription reveals the presence of a promoter region located upstream of the previously recognized SlyA repressed promoter . The newly identified upstream promoter region did not respond to SlyA but was activated by Mg(II) starvation in a PhoP-dependent manner . We present here evidence for a direct link between two transcription factors (PhoP and SlyA) crucial for Salmonella virulence. Food Addit Contam, 2003 May, 20(5), 427 - 37 Differential modulation of enterocyte-like Caco-2 cells after exposure to short-chain fatty acids; Malago JJ et al.; The response of intestinal epithelial cells to short-chain fatty acids, which are increasingly used as food additives, was investigated . Human small intestinal epithelial cell model Caco-2 cells were exposed to formate, propionate and butyrate to assess their effect on cellular growth, metabolism, differentiation and protection against bacteria . The Caco-2 cells were entirely grown in the different short-chain fatty acids and respective growth patterns were determined . Differentiated cells were exposed to 0-20 mM short-chain fatty acids for 48 h and changes in DNA, RNA, (glyco)protein syntheses, sucrase isomaltase activity, transepithelial electrical resistance and protection against Salmonella enteritidis were measured . The short-chain fatty acids, altered linearly and differentially the growth pattern ranging from stimulation by formate to inhibition by butyrate . Formate inhibited cellular metabolism . Low concentrations of up to 5 mM propionate and 2 mM butyrate stimulated metabolism, while higher doses were inhibitory . Formate had no effect on sucrase isomaltase enzyme activity and transepithelial electrical resistance, whereas propionate and butyrate increased these markers of differentiation . Infection with S . enteritidis did not benefit from the short-chain fatty acid-induced transepithelial electrical resistance . It is concluded that formate, propionate and butyrate selectively and differentially modulate growth characteristics, cellular metabolism, sucrase isomaltase activity and transepithelial electrical resistance in a concentration- and carbon atom-related fashion . The short-chain fatty acid-induced transepithelial electrical resistance does not confer protection against S . enteritidis. Biochem Soc Trans, 2003 Jun, 31(Pt 3), 520 - 2 What can structure tell us about in vivo function? The case of aminoglycoside-resistance genes; Vetting M et al.; Resistance to antibiotics used in the treatment of bacterial infections is an expanding clinical problem . Aminoglycosides, one of the oldest classes of natural product antibiotics, exert their bactericidal effect as the result of inhibiting bacterial protein synthesis by binding to the acceptor site of the 30 S ribosomal subunit . The most common mechanism of clinical resistance to aminoglycosides results from the expression of enzymes that covalently modify the aminoglycoside . We will discuss the enzymology and structure of two representative chromosomally encoded aminoglycoside N-acetyltransferases, Mycobacterium tuberculosis AAC(2')-Ic and Salmonella enterica AAC(6')-Iy, and speculate about their possible physiological function and substrates. Crit Care Med, 2003 May, 31(5), 1502 - 8 Effects of titrated arginine vasopressin on hemodynamic variables and oxygen transport in healthy and endotoxemic sheep; Westphal M et al.; OBJECTIVE: To determine the effects of titrated arginine vasopressin (AVP) alone or in combination with norepinephrine (NE) on hemodynamics and oxygen transport in healthy and endotoxemic sheep . DESIGN: Prospective controlled trial . SETTING: University research laboratory . SUBJECTS: Six adult ewes . INTERVENTIONS: Healthy sheep received AVP as a titrated infusion, initiated with 0.6 units/hr and increased by 0.6 units/hr every 15 mins, either until mean arterial pressure was increased by 20 mm Hg vs . baseline or a maximum of 3.6 units/hr was administered . After 90 mins, AVP infusion was continued with the investigated dosage, and NE (0.2 microg x kg(-1) x min(-1)) was also infused for 90 mins . After a 24-hr period of recovery, endotoxemia was induced and maintained (Salmonella typhosa endotoxin, 10 ng x kg(-1) x min(-1)) in the same sheep for the next 19 hrs . After 16 hrs of endotoxemia, AVP and NE were administered as described previously . MEASUREMENTS AND MAIN RESULTS: Hemodynamics were obtained at baseline, every 15 mins during the titration period, and 60 and 90 mins after additional NE infusion . Variables of oxygen transport were calculated before and after the titration period . In healthy and endotoxemic sheep, AVP reduced heart rate and cardiac index (p <.001) and compromised oxygen delivery (p <.001) and oxygen consumption (healthy sheep, p =.003; endotoxemic sheep, p <.001) . Vasopressin infusion did not alter mean pulmonary arterial pressure but increased pulmonary vascular resistance index in both groups (p <.001) . Additional infusion of NE further augmented mean arterial pressure and increased cardiac index during endotoxemia (p <.001) . This was accompanied by an increase in oxygen delivery and consumption (p <.05 each) . CONCLUSIONS: During ovine endotoxemia, AVP decreased cardiac index, compromised oxygen delivery, and increased pulmonary vascular resistance index . These side effects may limit its use as a sole vasopressor during sepsis . Potentially, a simultaneous infusion of AVP and NE could represent a useful therapeutic option. Eur J Med Chem, 2003 May, 38(5), 533 - 6 Hypervalent iodine mediated synthesis of 1-aryl/hetryl-1,2,4-triazolo{4,3-a} pyridines and 1-aryl/hetryl 5-methyl-1,2,4-triazolo{4,3-a}quinolines as antibacterial agents; Sadana AK et al.; Oxidation of 2-pyridyl and 2-quinylhydrazones with iodobenzene diacetate (IBD) in dichloromethane yield 1-aryl/hetryl-1,2,4-trizolo-{4,3-a} pyridines (3a-f) and 1-aryl/hetryl-5-methyl-1,2,4-triazolo{4,3-a} quinolines (6a-f) . Seven compounds were tested in vitro for their antibacterial activity . 1-(5'-Nitro-2-furyl)-5-methyl-1,2,4-triazolo{4,3-a}quinoline (6e) was associated with substantially higher antibacterial activity than some commercial antibiotics against Salmonella typhi at MIC i.e . 10 microg mL(-1). Eur Respir J, 2003 May, 21(5), 749 - 52 Rigid bronchoscopy induces bacterial translocation: an experimental study in rats; Nayci A et al.; Bronchoscopy has the potential to propagate infections . Bacterial translocation was hypothesised to be the cause of infections observed following bronchoscopy and this study was designed to assess the risk of bacterial translocation following rigid bronchoscopy in rats . A total of 30 rats were evaluated . The study group (n=15) underwent rigid bronchoscopy . Arterial blood gas analysis was performed in all rats . Blood and tissue cultures from the ileum, caecum, mesenteric lymph nodes, liver, spleen, mediastinal lymph nodes and lung were obtained 24 h following bronchoscopy . Bacterial translocation to the mesenteric lymph nodes was found in seven of 15 rats (46.7%) that underwent bronchoscopy, compared with none of the controls . Of the seven positives, three rats (42.8%) also demonstrated other organ involvement, such as the liver and spleen . Escherichia coli, Salmonella typhymirium, S . enteritidis and Pseudomonas spp . were found as translocating bacteria . In the study group, pH and arterial oxygen tension were significantly lower and arterial carbon dioxide tension was higher, compared with controls . This study shows that rigid bronchoscopy may induce bacterial translocation in rats . Further investigations aimed at understanding the clinical consequences of this phenomenon are warranted. Bioresour Technol, 2003 Apr, 87(2), 161 - 6 A review of survival of pathogenic bacteria in organic waste used in biogas plants; Sahlstrom L; Anaerobic digestion is one way of handling biowaste and generating energy in the form of methane (biogas) . The digested residue may be used as fertiliser on agricultural land . Biowaste is known to contain pathogenic bacteria such as Salmonella and other microorganisms that may be a health risk for both people and animals . The biosecurity risk associated with using digested residue as fertiliser is hard to assess, but this risk cannot be neglected . It is of greatest importance that the treatment in the biogas plants (BGPs) minimise the survival of pathogens . Temperature is the most important factor when considering the reduction of pathogens in BGP, but there are also other factors involved . Different indicator bacteria are used to evaluate the hygienic treatment, but an indicator that is good enough to give an overall picture has not yet been found. Vaccine, 2003 Jun 1, 21 Suppl 2, S24 - 34 Anti-cytokine therapeutics and infections; Dinarello CA; In view of the increasing use of anti-cytokine-based therapies to treat autoimmune diseases, the role of specific cytokines in host defense against infection has become a highly relevant area of investigation . There are over 300,000 patients worldwide being treated with agents that specifically block the biological activities of interleukin-1 (IL-1) or tumor necrosis factor (TNF) for reducing the severity of autoimmune diseases such as rheumatoid arthritis, Crohn's disease or psoriasis . Those patients receiving anti-TNF-alpha or IL-1 blocking therapies are treated on a chronic basis . Studies suggest that other chronic inflammatory diseases will benefit from anti-cytokine therapies . However, there is a growing body of clinical evidence that neutralization of TNF-alpha is associated with an increased risk of opportunistic infections, including mycobacterial diseases . Blockade of IL-1 activity with the IL-1 receptor antagonist (IL-1Ra) appears, at present, to be relatively safe . However, because of physician under reporting (some estimates of reporting being less than 5% of these infections), the true incidence of infections, both serious and non-serious, will remain unknown . Does the increase in infections associated with anti-cytokine-based therapies come as a surprise? Of the two components of host defense, the innate and the acquired responses, which are affected by anti-cytokine therapies? From a wealth of rodent studies using live infection models, the following conclusions can be drawn: (1) neutralization or gene deletion for TNF-alpha is frequently associated with reduction of host defense in models of live Gram-positive or Gram-negative infections as well as infection by intracellular microbes such as Salmonella and Listeria; (2) absence of the IL-1 receptor can also result in decreased resistance to Listeria or Gram-positive bacteria and (3) TNF-alpha and IFN-gamma are required for defense against infection caused by Mycobacterium tuberculosis. Poult Sci, 2003 May, 82(5), 721 - 6 Effect of two candidate genes on the Salmonella carrier state in fowl; Beaumont C et al.; Selection for increased resistance to Salmonella carrier-state (defined as the persistency of the bacteria 4 wk after inoculation) could reduce the risk for the consumer of food toxi-infections . The effects of two genomic regions on chromosomes 7 and 17 harboring two genes, NRAMP1 (SLC11A1) and TLR4, known to be involved in the level of chicken infection 3 d after inoculation by Salmonella were thus tested on a total of 331 hens orally inoculated at the peak of lay with 10(9) bacteria . The animals and their parents were genotyped for a total of 10 microsatellite markers mapped on chromosomes 7 and 17 . Using maximum likelihood analysis and interval mapping, it was found that the SLC11A1 region was significantly involved in the control of the probability of spleen contamination 4 wk after inoculation . Single nucleotide polymorphisms (SNP) within the SLC11A1 and TLR4 gene were tested on those animals as well as on a second batch of 279 hens whose resistance was assessed in the same conditions . As the former was significantly associated with the risk of spleen contamination and the number of contaminated organs, SLC11A1 appears to be involved in the control of resistance to Salmonella carrier state . The involvement of the TLR4 gene was also highly suspected as a significant association between SNP within the gene, and the number of contaminated organs was detected. J Environ Health, 2003 May, 65(9), 9 - 14; quiz 27-8 Growth and survival of selected pathogens in margarine-style table spreads; Guentert AM et al.; Although margarine-style table spreads can have a pH above 4.6 and a water activity greater than 0.85, there is some question if such products can support the growth of pathogenic bacteria . The objective of this study was to evaluate the growth and survival of Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhi in 60-percent- and 70-percent-vegetable-oil, margarine-style, water-in-oil-emulsion table spreads stored at different temperatures . Samples of 25 grams of each table spread were inoculated with 1 x 10(3) cells of each bacterial mixture . The samples were stored at 5 degrees C, 7 degrees C, and 21 degrees C, and the microbial population in colony-forming units per gram (CFU/gram) was enumerated over time . In almost all storage conditions, bacterial levels were shown to decrease over time . Inactivation was observed in (listed from fastest to slowest, respectively) S . aureus, L . monocytogenes, E . coli O157:H7, and S . typhi . Growth was observed only for S . typhi in table spreads stored at 21 degrees C, but the rate of growth was extremely slow . Based on these findings, the table spreads evaluated in this study are not potentially hazardous foods, and cold temperature storage is not necessary from a food safety perspective. Infect Immun, 2003 Jun, 71(6), 3392 - 401 Contribution of proton-translocating proteins to the virulence of Salmonella enterica serovars Typhimurium, Gallinarum, and Dublin in chickens and mice; Turner AK et al.; We investigated the attenuating effects of a range of respiratory chain mutations in three Salmonella serovars which might be used in the development of live vaccines . We tested mutations in nuoG, cydA, cyoA, atpB, and atpH in three serovars of Salmonella enterica: Typhimurium, Dublin, and Gallinarum . All three serovars were assessed for attenuation in their relevant virulence assays of typhoid-like infections . Serovar Typhimurium was assessed in 1-day-old chickens and the mouse . Serovar Gallinarum 9 was assessed in 3-week-old chickens, and serovar Dublin was assessed in 6-week-old mice . Our data show variation in attenuation for the nuoG, cydA, and cyoA mutations within the different serovar-host combinations . However, mutations in atpB and atpH were highly attenuating for all three serovars in the various virulence assays . Further investigation of the mutations in the atp operon showed that the bacteria were less invasive in vivo, showing reduced in vitro survival within phagocytic cells and reduced acid tolerance . We present data showing that this reduced acid tolerance is due to an inability to adapt to conditions rather than a general sensitivity to reduced pH . The data support the targeting of respiratory components for the production of live vaccines and suggest that mutations in the atp operon provide suitable candidates for broad-spectrum attenuation of a range of Salmonella serovars. Infect Immun, 2003 Jun, 71(6), 3285 - 93 Characterization of an iroBCDEN gene cluster on a transmissible plasmid of uropathogenic Escherichia coli: evidence for horizontal transfer of a chromosomal virulence factor; Sorsa LJ et al.; The chromosomal iroBCDEN gene cluster first described for Salmonella enterica is involved in the uptake of catecholate-type siderophore compounds . An orthologous gene cluster has recently been detected in Escherichia coli strains which cause extraintestinal disease . This E . coli iroBCDEN gene cluster has an impact on virulence and has been reported to be located in a pathogenicity island on the chromosome . In this study we characterized an iro gene cluster of a uropathogenic E . coli isolate which is located on a transmissible plasmid related to the R64 plasmid of S . enterica . This cluster is highly homologous to the chromosomal iro cluster of E . coli . When introduced into an E . coli fepA cir fiu aroB mutant, IroN, but not IroBCDE, mediated the utilization of structurally related catecholate siderophores, including 2,3-dihydroxybenzoyl-L-serine, 2,3-dihydroxybenzoyl-D-ornithine, 2,3-dihydroxybenzoic acid, and enterochelin . This study supports the idea of an ongoing horizontal transfer of putative virulence factors and the mobilization of single virulence gene clusters, which lead to a modular assembly of virulence determinants such as pathogenicity islands. Antimicrob Agents Chemother, 2003 Jun, 47(6), 2006 - 8 Salmonella enterica serovar typhi strains isolated in Korea containing a multidrug resistance class 1 integron; Pai H et al.; Six strains of Salmonella enterica serovar Typhi which were resistant to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, streptomycin, tetracycline, and gentamicin were isolated in Korea . This multidrug resistance was transferred by a conjugative plasmid of about 50 kb . The plasmid harbored a class 1 integron, which included six resistance genes, aacA4b, catB8, aadA1, dfrA1, aac(6')-IIa, and the novel blaP2, in that order . All of the isolates showed the same-size plasmids and the same ribotyping patterns, which suggests a clonal spread of these multidrug-resistant isolates. Antimicrob Agents Chemother, 2003 Jun, 47(6), 2002 - 5 Evolution of antibiotic resistance in Salmonella enterica serovar typhimurium strains isolated in the Czech Republic between 1984 and 2002; Faldynova M et al.; In a collection of 66 Salmonella enterica serovar Typhimurium strains isolated between 1984 and 2002 in the Czech Republic, genes coding for antibiotic resistance were determined by using specific PCRs . We found that the pentadrug-resistant ACSSuT clone first appeared in the Czech Republic in 1990 . A new variant of the aadA gene designated aadA21 is described, the 5' end of which was identical to aadA2 and the 3' end of which was identical to aadA1. J Pediatr Hematol Oncol, 2003 May, 25(5), 390 - 5 Positive blood cultures in sickle cell disease: time to positivity and clinical outcome; Norris CF et al.; PURPOSE: To prospectively identify all cases of bacteremia in children with sickle cell disease (SCD), establish time to positivity for various microorganisms, correlate clinical findings with microbiology data, and determine the antibiotic resistance pattern of the pneumococcal isolates . METHODS: All positive blood cultures from children with SCD followed at the Children's Hospital of Philadelphia from January 1993 through May 2001 were included . Isolates were classified as pathogen or contaminant . Demographic and clinical information was abstracted from the medical records . Time to positivity and antibiotic resistance data were generated in the microbiology laboratory . RESULTS: One hundred forty-one positive blood culture bottles were obtained during distinct febrile episodes . Thirty-nine percent contained pathogens and 61% contained contaminants . The average time to positivity was 17.1 hours in the pathogen group and 29.5 hours in the contaminant group (P < 0.0001) . Streptococcus pneumoniae was the most common pathogen (42% of total), with a mean patient age of 3.5 years . Gram-negative rods were the second most common organism (28% of total), with a mean patient age of 8.1 years . Thirty-one percent of the pneumococcal isolates were resistant to penicillin . Thirty-five percent of the pneumococcal isolates grew from children with a focus of infection . Acute chest syndrome was noted in 26% of patients with a positive blood culture for S . pneumoniae . Sixty-seven percent of Salmonella isolates and 50% of Staphylococcus aureus isolates grew from patients who developed osteomyelitis . CONCLUSIONS: The average time to positivity for pathogens can be used in conjunction with other factors to determine the length of observation required for children with SCD who present with febrile illness . Chest radiographs should be obtained on children with SCD who are bacteremic with S . pneumoniae . Bone scans should be obtained on children with SCD who are bacteremic with Salmonella or S . aureus. FEMS Microbiol Lett, 2003 May 16, 222(1), 25 - 32 Null mutations in the essential gene yrfF (mucM) are not lethal in rcsB, yojN or rcsC strains of Salmonella enterica serovar Typhimurium; Costa CS et al.; Insertion of factor MudJ in the intergenic region between divergent genes yrfF and yrfE, at centisome 76 in the genome of Salmonella enterica serovar Typhimurium LT2, confers the characteristics recently described for mucM mutants, i.e . mucoidy and resistance to mecillinam . Cloning of the intergenic region plus either the yrfF or the yrfE gene in a multicopy plasmid showed that only the plasmid carrying the yrfF gene complemented mucM mutants, thus suggesting that mucM mutations are in fact yrfF mutations . A null yrfF mutation obtained by insertion of a kanamycin cassette into the yrfF open reading frame (yrfF28::Kan) produced abortive colonies when transduced to a wild-type strain but was normally accepted by rcsB, rcsC or yojN strains . Neither mutations preventing synthesis of the capsular exopolysaccharide colanic acid (cps, galE) nor rcsA mutations, which reduce expression of cps genes, conferred tolerance to the lethal yrfF28::Kan mutation . Spontaneous suppressor mutations arose very frequently in abortive yrfF28::Kan colonies, and all of them affected either rcsC, yojN, or rcsB genes . Thus, the lethal effect caused by inactivation of gene yrfF appears to be mediated by a function that is dependent on the rcsC-yojN-rcsB phosphorelay system but does not involve synthesis of colanic acid. Int Immunopharmacol, 2003 May, 3(5), 693 - 706 The use of selective pharmacological inhibitors to delineate signal transduction pathways activated during complement receptor-mediated degranulation in chicken heterophils; Kogut MH et al.; Complement receptors (CRs), along with Fc receptors, play a primary role in the removal of bacterial pathogens in poultry . The binding of serum-opsonized bacteria to CR results in the secretion of both toxic oxygen metabolites and antibacterial granules . We have previously shown that the stimulation of chicken heterophils with serum-opsonized Salmonella enteritidis induced tyrosine kinase-dependent phosphorylation regulated degranulation . In the present studies, we used selective pharmacological inhibitors to investigate the roles of protein tyrosine kinases, phospholipases C and D (PLC and PLD), phosphatidylinositol 3'-kinase (PI3-K), and the super family of mitogen-activated protein kinases (MAPKs) on CR-mediated heterophil degranulation . Inhibitors of receptor-linked tyrosine kinases (the tryphostins AG1478 and AG1296) had no attenuating effects on CR-mediated degranulation . However, PP2, a selective inhibitor of the src family of protein tyrosine kinases, and piceatannol, an inhibitor of Syk tyrosine kinases, both significantly attenuated the CR-mediated degranulation . Additionally, the specific inhibitors of PLC, U73122, and PI3-K, LY294002, significantly decreased CR-mediated heterophil degranulation . Two inhibitors of PLD-mediated signaling, 2,3-diphosphoglycerate (2,3-DPG) and 1-butanol, hindered degranulation . Addition of purified PLD restored control levels of degranulation in heterophils in which PLD was inhibited . Lastly, SP600125, a selective inhibitor of c-Jun N-terminal kinase (JNK), inhibited degranulation; whereas neither PD98059, the inhibitor of p38 MAPK, nor SB203580, the inhibitor of extracellular signal-regulated kinase, had any effect on CR-mediated heterophil degranulation . These studies demonstrate that CRs on chicken heterophils lack intrinsic tyrosine kinase activity, but that binding of serum-opsonized bacteria activates both proximal tyrosine kinases (src and Syk kinases), but differentially activates downstream tyrosine kinases (JNK, but not p38 nor ERK) . Activation of src and Syk kinases plays a significant role in signal transduction of heterophil degranulation probably by stimulating downstream phosphorylation of PLC, PLD, and PI3-K . PI3-K has also been recently shown to be an upstream mediator of JNK activation, suggesting that this enzyme can induce signaling as both a lipid kinase and protein kinase . Engaging CRs on chicken heterophils activates a proximal tyrosine kinase (src and Syk kinases)-->PLC (PLD)-->PI3-K-->JNK signal transduction pathway that induces degranulation. Adv Exp Med Biol, 2003, 529, 407 - 13 Yersinia outer protein E, YopE . A versatile type III effector molecule for cytosolic targeting of heterologous antigens by attenuated Salmonella; Russmann H; Many Gram-negative pathogens evade the host's immune response by utilizing a specialized protein secretion machinery, known as type III secretion system (TTSS) . Virulence factors such as the Yersinia outer protein E (YopE) are delivered directly into the cytosol of target cells in a TTSS-dependent fashion . This unique translocation mechanism can be used by attenuated Salmonella carrier vaccines for the delivery of heterologous antigens fused to YopE into the MHC class I-restricted antigen processing pathway . In orally immunized mice, this novel vaccination strategy results in the induction of pronounced peptide-specific cytotoxic CD8 T cell responses. RNA, 2003 Jun, 9(6), 760 - 8 Transfer RNA modifications that alter +1 frameshifting in general fail to affect -1 frameshifting; Urbonavicius J et al.; Using mutants (tgt, mnmA(asuE, trmU), mnmE(trmE), miaA, miaB, miaE, truA(hisT), truB) of either Escherichia coli or Salmonella enterica serovar Typhimurium and the trm5 mutant of Saccharomyces cerevisiae, we have analyzed the influence by the modified nucleosides Q34, mnm(5)s(2)U34, ms(2)io(6)A37, Psi39, Psi55, m(1)G37, and yW37 on -1 frameshifts errors at various heptameric sequences, at which at least one codon is decoded by tRNAs having these modified nucleosides . The frequency of -1 frameshifting was the same in congenic strains only differing in the allelic state of the various tRNA modification genes . In fact, in one case (deficiency of mnm(5)s(2)U34), we observed a reduced ability of the undermodified tRNA to make a -1 frameshift error . These results are in sharp contrast to earlier observations that tRNA modification prevents +1 frameshifting suggesting that the mechanisms by which -1 and +1 frameshift errors occur are different . Possible mechanisms explaining these results are discussed. Int J Med Microbiol, 2003 Apr, 293(1), 107 - 12 Bacterial type III translocation: a unique mechanism for cytosolic display of heterologous antigens by attenuated Salmonella; Russmann H; Upon infection, Gram-negative animal and plant pathogens evade the host immune response by utilizing a specialized protein secretion machinery, known as type III secretion system, for the export of bacterial virulence factors delivered directly into the cytosol of target cells . This unique translocation mechanism can be used for the delivery of large protein fragments derived from immunodominant viral and bacterial heterologous antigens into the MHC class I-restricted antigen-processing pathway by attenuated Salmonella carrier vaccines . In orally immunized mice, this novel vaccination strategy results in the induction of pronounced peptide-specific cytotoxic CD8 T cell responses. Rev Inst Med Trop Sao Paulo, 2003 Mar-Apr, 45(2), 115 - 7 Epub 2003 May 14. Liver abscess due to Salmonella enteritidis in a returned traveler with HIV infection: case report and review of the literature; Vidal JE et al.; Bacteremia due to non-typhi Salmonella is more frequent in patients infected with the human immunodeficiency virus (HIV) . However, focal complications have been rarely described . We report a case of liver abscess due to Salmonella enteritidis in an HIV-infected patient who recently returned to Sao Paulo, Brazil, from a trip in the Caribbean . A good clinical and radiological response was seen with both percutaneous catheter drainage and antibiotic treatment . To our knowledge, this is the first culture proven case of non-typhi Salmonellaliver abscess in an HIV-infected patient in Brazil. Rev Inst Med Trop Sao Paulo, 2003 Mar-Apr, 45(2), 59 - 63 Epub 2003 May 14. Phenotypic and molecular characterization of Salmonella Enteritidis strains isolated in São Paulo, Brazil; Fernandes SA et al.; In Sao Paulo State, Brazil, the epidemic increase in isolation of Salmonella Enteritidis has been observed since 1994 . A total of 105 S . Enteritidis strains (72 from human and 33 from non-human sources) isolated during the period 1975-1995, previously characterized by phage typing, was analyzed by antimicrobial susceptibility, plasmid profile, and ribotyping . Over 70% of the strains were susceptible to all antimicrobial agents tested, however, multiple resistance to antimicrobials was observed among the studied strains, mainly those from hospitalized patients . Phage type 8 (PT-8) was predominant among the strains isolated during the period of 1975-1992, but in the following years, PT-4 was the most frequent phage type identified . Seven different plasmid profiles were detected and 96% of the isolates harbored a plasmid of approximately 36 MDa . Ribotyping discriminated fourteen ribotypes (R1 to R14) among the strains examined . By analysis of dendrogram the strains were included in three groups with similarity level of 60% . The obtained results indicate that, a single ribotype (R11), determined for PT-4 strains isolated from 1993, characterizes the epidemic clone of S . Enteritidis in our region. J Bacteriol, 2003 Jun, 185(11), 3480 - 3 Synthesis and localization of the Salmonella SPI-1 type III secretion needle complex proteins PrgI and PrgJ; Sukhan A et al.; An essential component of type III secretion systems (TTSS) is a supramolecular structure termed the needle complex . In Salmonella enterica, at least four proteins make up this structure: InvG, PrgH, PrgK, and PrgI . Another protein, PrgJ, is thought to play a role in the assembly of this structure, but its function is poorly understood . We have analyzed the expression and localization of PrgJ and the needle protein PrgI in different S . enterica serovar Typhimurium mutant strains . We found that the levels of PrgI and PrgJ were significantly reduced in a TTSS-deficient invA mutant strain and that the decreased levels were due to protein instability . In addition, we found that PrgJ, although associated with the needle complex in wild-type S . enterica serovar Typhimurium, was absent from needle complexes obtained from an invJ mutant strain, which exhibits very long needle substructures . We suggest that PrgJ is involved in capping the needle substructure of the needle complex. J Bacteriol, 2003 Jun, 185(11), 3473 - 5 Genomic structure of the Salmonella enterica serovar Typhimurium DT 64 bacteriophage ST64T: evidence for modular genetic architecture; Mmolawa PT et al.; The complete sequence of the double-stranded DNA genome of a serotype-converting temperate bacteriophage, ST64T, was determined . The 40,679-bp genomic sequence of ST64T has an overall GC content of 47.5% and was reminiscent of a number of lambdoid phages, in particular, P22 . Inferred proteins of ST64T which exhibited a high degree of sequence similarity to P22 proteins (>90%) included the functional serotype conversion cassette, integrase, excisionase, Abc1, Abc2, early antitermination (gp24), NinD, NinH, NinZ, packaging (gp3 and gp2), head (with the exception of gp26, gp7, gp20, and gp16), and tail proteins . The putative immunity genes were highly related to those of Salmonella enterica serotype Typhimurium phage L, whereas the lysis genes were almost identical to those of S . enterica serovar Typhimurium PS3. Mol Microbiol, 2003 May, 48(4), 1131 - 43 Dual regulation by phospho-OmpR of ssrA/B gene expression in Salmonella pathogenicity island 2; Feng X et al.; Expression of genes located on Salmonella pathogenicity island 2 (SPI-2) is required for systemic infection in mice . This region encodes a type III secretion system, secreted effectors and the two-component regulatory system SsrA/B (also referred to as SpiR), as well as additional uncharacterized genes . In the present work, we demonstrate that phospho-OmpR (OmpR-P) functions as an activator at the spiC-ssrA/B locus . There are two promoters at spiR; one is upstream of ssrA and the other upstream of ssrB . Our results indicate that, in contrast to many two-component regulatory systems, regulation of the sensor kinase SsrA appears to be uncoupled and distinct from regulation of the response regulator SsrB . OmpR regulation of ssrA/B is one of only a few examples known in which a two-component response regulator directly regulates the expression of another two-component regulatory system. Mol Microbiol, 2003 May, 48(4), 1043 - 57 Substrate specificity of type III flagellar protein export in Salmonella is controlled by subdomain interactions in FlhB; Fraser GM et al.; FlhB, an integral membrane protein, gates the type III flagellar export pathway of Salmonella . It permits export of rod/hook-type proteins before hook completion, whereupon it switches specificity to recognize filament-type proteins . The cytoplasmic C-terminal domain of FlhB (FlhBC) is cleaved between Asn-269 and Pro-270, defining two subdomains: FlhBCN and FlhBCC . Here, we show that subdomain interactions and cleavage within FlhB are central to substrate-specificity switching . We found that deletions between residues 216 and 240 of FlhBCN permitted FlhB cleavage but abolished function, whereas a deletion spanning Asn-269 and Pro-270 abolished both . The mutation N269A prevented cleavage at the FlhBCN-FlhBCC boundary . Cells producing FlhB(N269A) exported the same amounts of hook-capping protein as cells producing wild-type FlhB . However, they exported no flagellin, even when the fliC gene was being expressed from a foreign promoter to circumvent regulation of expression by FlgM, which is itself a filament-type substrate . Electron microscopy revealed that these cells assembled polyhook structures lacking filaments . Thus, FlhB(N269A) is locked in a conformation specific for rod/hook-type substrates . With FlhB(P270A), cleavage was reduced but not abolished, and cells producing this protein were weakly motile, exported reduced amounts of flagellin and assembled polyhook filaments. J Appl Microbiol, 2003, 94(6), 1036 - 42 Decontamination of pork carcasses during scalding and the prevention of Salmonella cross-contamination; Bolton DJ et al.; AIMS: The objective of this study was to establish critical temperature limits to prevent cross-contamination of pork carcasses during scalding . METHODS AND RESULTS: Mixtures of antibiotic-resistant mutants of Salmonella species were heat treated at 50, 55 and 60 degrees C in samples of commercial scald tank water . Surviving cell numbers were estimated by plating treated suspensions on (i) . tryptone soya agar (TSA) and (ii) . on TSA, overlaid with brilliant green agar plus nalidixic acid and streptomycin sulphate and used to estimate D-values for the treated mixed cell suspensions . CONCLUSIONS: A time-temperature combination of 1.4 min at 60 degrees C is required to achieve a 1 log reduction in Salmonella in scald tank water . The predicted equivalent at 65 degrees C is 0.18 min . SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides data and a model to enable pork processors to identify and apply processing parameters to limit the risks of transfer of Salmonella between pig carcasses during commercial scalding operations. J Appl Microbiol, 2003, 94(6), 1024 - 9 Molecular fingerprinting evidence of the contribution of wildlife vectors in the maintenance of Salmonella Enteritidis infection in layer farms; Liebana E et al.; AIMS: To provide molecular fingerprinting evidence of the contribution of wildlife vectors in the on-farm epidemiology of Salmonella Enteritidis infections . METHODS AND RESULTS: Salmonella Enteritidis strains were isolated from wildlife and from farm environment samples collected in 10 egg layer farms . Isolates were typed using plasmid profiling, XbaI-pulsed field gel electrophoresis and PstI-SphI ribotyping . In all 10 farms we were able to identify the same S . Enteritidis clones in wildlife vectors and farm environment . On several occasions the same clones were found before and after cleansing and disinfecting the farm premises . Also in some instances the same clones were present in mice samples, egg contents and spent hens . CONCLUSIONS: Definitive molecular evidence for the involvement of several wildlife species (mice, rats, flies, litter beetles and foxes) in the maintenance of S . Enteritidis infection on farms has been presented . Failures in biosecurity seriously compromise the control of this pathogen on laying farms . SIGNIFICANCE AND IMPACT OF THE STUDY: This paper reports on the use of molecular tools for the study of the epidemiology of S . Enteritidis . It gives useful information to be considered in control programmes for this organism on poultry farms. Scand J Infect Dis, 2003, 35(3), 199 - 202 Repeated gallium-67 scan demonstrating an occult mycotic aneurysm of the aortic arch due to Salmonella; Kao PF et al.; A 71 y-old female with 40 degrees C fever and a change in consciousness during haemodialysis was referred for a gallium-67 scan, which revealed a horseshoe-like radioactive accumulation in the mediastinal region . Salmonella enteritidis was isolated from blood culture . Magnetic resonance imaging confirmed an aortic arch aneurysm . The patient died without surgery. Afr J Med Med Sci, 2002 Sep, 31(3), 229 - 33 CD4+ and CD8+ lymphocytes and clinical features of HIV seropositive Nigerians on presentation; Onyemelukwe GC et al.; Eighty of 200 HIV seropositive patients admitted in the medical wards of Ahmadu Bello University Teaching Hospital, Zaria from year 1995 to 1997 were studied on presentation and compared to 40 age and sex matched controls . The main clinical features observed included weight loss, pyrexia, diarrhoea, lymphadenopathy, anaemia and pruritic dermatosis . Sixty-two of the 80 patients (73.2%) presented at stages 3 and 4 of WHO Clinical and Laboratory staging . Thirty (30) percent of these patients died between a period of one to four months after presentation . The main diseases complicating HIV infection at presentation of the 80 patients were Mycobacterium tuberculosis infection (30%), acute bacterial infections (with Salmonella typhi, Streptococcus pneumoniae and Staphylococcus aureus) (24%), candidiasis (14%) and Kaposi sarcoma (2%) . Seropositivity for HIV types was found to be HIV-I alone in 43.5% of cases; HIV-II alone in 14% and both HIV-I and II in 42% of cases . Risk factors associated with HIV infection were multiple sexual partners (73%), sexually transmitted disease (70%), and unscreened blood transfusion (1%) . HIV positive patients had a mean CD4+ T-cells of 0.24 x 10(9) +/- 0.17 which was significantly lower than the mean of 0.6 +/- 0 . 17 x 10(9)/L for controls (P < 0.05 students t-test) . Thirty (35%) of the patients had CD4+ counts of less than 0.2 x 10(9)/L (200 cells/microl) at presentation . The mean CD3+ lymphocytes count was 0.51 +/- 0.24 x 10(9)/L for patients and 1.04 +/- 0.71 x 10(9)/L for controls . The mean CD8+ lymphocyte count in patients was 0.29 +/- 0.19 x 10(9)/L and 0.44 x 10(9)/L for controls . Both CD3+ and CD8+ lymphocyte populations were statistically lower in patients than controls (P < 0.05). Rev Inst Med Trop Sao Paulo, 2003 Jan-Feb, 45(1), 1 - 4 Phage types of Salmonella enteritidis isolated from clinical and food samples, and from broiler carcasses in southern Brazil; dos Santos LR et al.; 272 isolates of Salmonella Enteritidis (111 isolated from frozen broiler chicken carcasses, 126 from human food and other biological materials involved in food poisoning outbreaks and 35 from different poultry materials) were selected for phage typing . From these, 111 were phage typed, 57.65% being classified as phage type 4, 32.43% as phage type 4a, 3.60% as phage type 6a and 0.90% as phage type 7, whereas 5.40% samples were not phage typeable . The predominance of phage type 4 is in agreement with the results published worldwide, and reinforces the need for studies related to the epidemiological meaning of these findings. Natl Toxicol Program Tech Rep Ser, 1988 Aug, 266, 1 - 166 NTP Toxicology and Carcinogenesis Studies of Monuron (CAS No . 150-68-5) in F344/N Rats and B6C3F1 Mice (Feed Studies); National Toxicology Program ; Carcinogenesis studies of monuron (greater than 99% pure), a substituted urea herbicide, were conducted by feeding diets containing 0, 750, or 1,500 ppm monuron to groups of 50 F344/N rats of each sex and 0, 5,000, or 10,000 ppm to groups of 50 B6C3F1 mice of each sex for 103 weeks . Survivors then were fed a control diet for 1 week, killed, and examined . Throughout most of the studies, mean body weights of dosed rats and mice of each sex were lower than those of the controls . Survival rates of low dose female rats and high dose male and female mice were increased relative to those of the controls . In 13-week toxicity studies, the lympho/hematopoietic system of rats and mice was the primary site affected . The lymphoid depletion found in these animals was not seen in rats or mice surviving to the end of the 104-week studies . Nonneoplastic changes associated with the long-term administration of monuron to rats included renal tubular cell cytomegaly, mainly involving the proximal convoluted tubules in male and female rats, and dose-related hepatic cytoplasmic changes in male rats . In the 104-week study, the kidneys and liver of male rats were the primary tissues affected . Long-term administration of monuron was associated with an increase in renal tubular cell adenomas (control, 0/50; low dose, 2/50; high dose, 7/50) and renal tubular cell adenocarcinomas (0/50; 1/50; 8/50) . Administration of monuron to male rats was associated with increased incidences of neoplastic nodules of the liver (1/50; 6/49; 7/50) and of neoplastic nodules or carcinomas (combined) of the liver (1/50; 6/49; 9/50) . Dosed male and female rats had decreased incidences of mononuclear cell leukemia; dosed male rats had lower incidences of pheochromocytomas of the adrenal glands and C-cell carcinomas of the thyroid gland; dosed female rats had reduced incidences of mammary gland fibroadenomas . In male mice, dose-related decreases occurred in the incidences of hepatocellular carcinomas (6/50; 5/49; 2/50) and hepatocellular adenomas or carcinomas (12/50; 8/49; 6/50); incidences of hepatocellular tumors in low dose female mice were reduced in dosed female mice (16/50; 8/50; 7/50) . Monuron was not mutagenic in Salmonella strains TA98, TA100, TA1535, or TA1537 in the presence or absence of Aroclor 1254-induced rat liver S9 . Monuron did induce chromosomal aberrations and sister chromatid exchanges in cultured Chinese hamster ovary cells . The data, documents and pathology materials from the 2-year studies of monuron have been audited . The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report . Under the conditions of these 2-year feed studies, there was clear evidence of carcinogenicity for male F344/N rats in that monuron caused increased incidences of tubular cell adenocarcinomas of the kidney, tubular cell adenomas of the kidney, and neoplastic nodules or carcinomas (combined) of the liver . Monuron induced cytomegaly of the renal tubular epithelial cells in both male and female F344/N rats . There was no evidence of carcinogenicity for female F344/N rats or for male or female B6C3F1 mice . Synonyms and Trade Names: N'-(4-chlorophenyl)-N,N-dimethylurea; 1,1-dimethyl-3-(p-chlorophenyl)urea; CMU; Karmex Monuron Herbicide; Telvar Infez Med, 1999, 7(4), 213 - 221 {Salmonella non-typhoid infection: new epidemiological findings}; Sagnelli E et al.; Food-borne infections are the most serious food safety problem in the world . In fact, they are responsible of millions of illnesses and thousand of deaths . Non-typhoid Salmonella infection is frequent world-wide and, although mild and self-limiting illness in normal subjects, it may cause a severe disease in patients with an immune-deficiency . Changes in the agents and in the vehicles of transmission and a higher number of patients with immune-depression have determined a world-spread of non-typhoid Salmonella infection in the last decades . The increased frequency of international travels and food commerce have been associated with outbreaks of unusual serotype of Salmonella . Moreover, drug-resistant Salmonella are emerged recently, as Ampicillin and Doxiciclin-resistant S . enteritidis or DT-104 multidrug-resistant S . typhimurium . The outbreak of Salmonella disease is also linked to diffusion of HIV infection and of other immunodeficiencies . The lack of controls in food industry, the frequent contamination of mass-distributed food products and the decreased opportunities to transmit for instruction on food safety, both in school and inside the family, are the causes of large-scale outbreaks J Med Microbiol, 2003 Jun, 52(Pt 6), 453 - 9 Development of acquired immunity to Salmonella; Mastroeni P et al.; Salmonella enterica serovar Typhi (S . typhi) causes human typhoid fever, a serious and widespread disease in developing countries . Other Salmonella serovars are associated with food-borne infections . The recent emergence of multi-drug-resistant Salmonella strains highlights the need for better preventive measures, including vaccination . The available vaccines against Salmonella infection do not confer optimal protection . The design of new Salmonella vaccines must be based on the identification of suitable virulence genes and on knowledge of the immunological mechanisms of resistance to the disease . Control and clearance of a vaccine strain rely on the phagocyte oxidative burst, reactive nitrogen intermediates, inflammatory cytokines and CD4(+) TCR-alphabeta(+) T cells and are controlled by genes including NRAMP1 and MHC class II . Vaccine-induced resistance to reinfection requires the presence of Th1-type immunological memory and anti-Salmonella antibodies . The interaction between T and B cells is essential for the development of resistance following vaccination . The identification of immunodeficiencies that render individuals more susceptible to salmonellosis must be taken into consideration when designing and testing live attenuated Salmonella vaccines . An ideal live Salmonella vaccine should therefore be safe, regardless of the immunological status of the vaccinee, but still immunogenic. J Food Prot, 2003 May, 66(5), 874 - 7 Impact of pH enhancement on populations of Salmonella, Listeria monocytogenes, and Escherichia coli O157:H7 in boneless lean beef trimmings; Niebuhr SE et al.; Boneless lean beef trimmings were inoculated with multiple strains of salmonellae, Listeria monocytogenes, and Escherichia coli O157:H7 at levels of ca . 6 log10 CFU/g . pH enhancement with ammonia gas was then used to increase the pH of the trimmings to ca . 9.6 . The product was then frozen, chipped, and compressed into blocks . pH enhancement reduced the populations of salmonellae, L . monocytogenes, and E . coli O157:H7 by approximately 4, 3, and 1 log10 cycles, respectively . After the product had been frozen and compressed into blocks, no salmonellae or E . coli O157:H7 were detectable by enumeration or after enrichment and isolation . The final populations of L . monocytogenes were reduced by ca . 3 log10 cycles relative to the initial populations . When uninoculated pH-enhanced lean boneless trimmings were blended with inoculated ground beef to a final concentration of 15% (wt/wt), pathogen populations in the ground beef were reduced by approximately 0.2 log10 cycles. J Food Prot, 2003 May, 66(5), 825 - 32 Effect of dry heating on the microbiological quality, functional properties, and natural bacteriostatic ability of egg white after reconstitution; Baron F et al.; Spray-dried egg white (powder) is widely used in the food industry because of its variety of functional properties and its practical advantages . Moreover, egg white powder is generally considered safe because it can withstand high temperatures that allow for the destruction of all pathogens, especially Salmonella . In France, two types of treatments are used to improve the functional properties (whipping and gelling) of dried egg white: standard storage at 67 degrees C for about 15 days and storage at 75 to 80 degrees C for 15 days . The objective of this study was to investigate the effects of two dry-heating treatments (storage at 67 and 75 degrees C for 15 days) on the subsequent ability of egg white to resist Salmonella growth after reconstitution . The impact on the endogenous microflora of the powder and on its functional properties was also considered . Both dry-heating treatments were efficient in destroying a large number of Salmonella . Dry heating at 75 degrees C affected the bacteriostatic ability of reconstituted egg white to a greater extent than did dry heating at 67 degrees C . This loss of bacteriostatic ability could be attributable to the thermal denaturation of ovotransferrin, resulting in a reduction in its activity as an iron chelator . However, dry heating at 75 degrees C resulted in improved functional properties . Ultimately, no complete compromise between better functional quality and the preservation of the bacteriostatic ability of egg white after reconstitution is possible . Our results underline the importance of the use of hygienic conditions with egg white powder, especially with powder subjected to high-temperature treatments. J Food Prot, 2003 May, 66(5), 787 - 92 rP33 activates bacterial killing by chicken peripheral blood heterophils; Crippen TL et al.; The protection of poultry from infection by Salmonella is of major concern with regard to human health because Salmonella is a common bacterial cause of foodborne diseases, and protection without the use of antibiotics is preferable in order to avoid possible complications involving antibiotic resistance . Salmonella immune lymphokine (SILK), produced by stimulated splenic T cells from Salmonella Enteritidis-immunized chickens, has been shown to confer protection against Salmonella infection on day-old chicks without the use of antibiotics . This protection results from the potentiation of an immune response following treatment with SILK . This study was undertaken to analyze a component of SILK, identified as P33, that is the product of the chicken mim-1 gene . A recombinant derivative expressing a domain of P33 (rP33) has been shown to be chemotactic for heterophils and is therefore instrumental in eliciting the immune response characteristic of SILK-induced protection against Salmonella infection in chicks . We report here that rP33 possesses the ability to activate antimicrobial responses from heterophils . The killing of Salmonella Enteritidis by heterophils was increased by in vitro treatment of the cells with rP33 . Treatment with rP33 also stimulated the degranulation of heterophils but did not induce an oxidative burst or upregulate phagocytosis . These results indicate that P33 is an active component of SILK, conferring protection against Salmonella Enteritidis by augmenting the antimicrobial activities of heterophils. J Food Prot, 2003 May, 66(5), 760 - 6 Irradiation D-values for Escherichia coli O157:H7 and Salmonella sp . on inoculated broccoli seeds and effects of irradiation on broccoli sprout keeping quality and seed viability; Rajkowski KT et al.; Like alfalfa sprouts, broccoli sprouts can be a vehicle for bacterial pathogens, which can cause illness when they are consumed . The gamma irradiation process was used to reduce numbers of bacterial pathogens on broccoli sprouts and seeds, and the effect of this process on the seeds was studied . The irradiation destruct values for Salmonella sp . and for strains of Escherichia coli O157:H7 inoculated on broccoli seeds were determined . Results obtained in this study indicate that a dose of 2 kGy reduced total background counts for broccoli sprouts from 10(6) to 10(7) CFU/g to 10(4) to 10(5) CFU/g and increased the shelf life of the sprouts by 10 days . Yield ratio (wt/wt), germination percentage, sprout length, and thickness were measured to determine the effects of various irradiation doses on the broccoli seeds . Results show a decreased germination percentage at a dose level of 4 kGy, whereas the yield ratio (wt/wt), sprout length, and thickness decreased at the 2-kGy dose level . The radiation doses required to inactivate Salmonella sp . and strains of E . coli O157:H7 were higher than previously reported values . D-values, dose required for a 1-log reduction, for the nonvegetable and vegetable Salmonella sp . isolates were 0.74 and 1.10 kGy, respectively . The values for the nonvegetable and vegetable isolated strains of Escherichia coli O157:H7 were 1.43 and 1.11 kGy, respectively . With the irradiation process, a dose of up to 2 kGy can extend the shelf life of broccoli sprouts . A dose of > 2 kGy would have an adverse effect on the broccoli seed and decrease the yield of broccoli sprouts. J Food Prot, 2003 May, 66(5), 741 - 7 Reducing Salmonella on apples with wash practices commonly used by consumers; Parnell TL et al.; The efficacy levels of practices used by consumers to wash smooth-surface fruits and vegetables were compared . Golden Delicious apples were spot inoculated near the blossom end with 50 microl of a cocktail of six serotypes of Salmonella enterica (with a total inoculum level of approximately 10(9) CFU per apple) . The inoculum was dried for 1.5 h, and apples were either treated immediately or held for 24 h prior to treatment . Treatments included wetting with approximately 5 ml of water, vinegar (5% acidity), or a 200-ppm chlorine solution, rubbing for 5 or 30 s, rinsing with 200 to 600 ml of 24 or 43 degrees C water, and drying with a sterile paper towel . Residual populations of Salmonella were determined by rubbing the treated apple for 30 s in 20 ml of Dey-Engley neutralizing broth and plating on tryptic soy agar and bismuth sulfite agar . Rubbing treatments carried out for 5 and 30 s both resulted in a significant reduction in Salmonella populations (1 log10 CFU per apple) relative to populations on samples held for 30 s . A 5-s rub followed by a 200-ml flowing-water rinse reduced populations by 3 log10 CFU per apple . No further decrease in population was obtained by rinsing with 400 or 600 ml of water . Increasing the rinse water temperature to 43 degrees C did not significantly improve microbial removal . Drying the apple with a sterile paper towel resulted in an additional decrease of approximately 0.4 log10 CFU per apple . A reduction of 3.2 log10 CFU was achieved with a combination of wetting with water, rubbing for 5 s, rinsing with 200 ml of water, and drying with a paper towel for apples inoculated just prior to or 24 h before treatment . Reductions obtained for apples treated with 5% vinegar and with a 200-ppm chlorine solution were significantly larger (2.1 to 3.2 log10 CFU per apple, respectively) than those achieved with water. J Food Prot, 2003 May, 66(5), 732 - 40 Comparative analysis of acid resistance between susceptible and multi-antimicrobial-resistant Salmonella strains cultured under stationary-phase acid tolerance-inducing and noninducing conditions; Bacon RT et al.; This study compared acid resistance levels among five antimicrobial-susceptible strains of Salmonella and five strains that were simultaneously resistant to a minimum of six antimicrobial agents . The induction of a stationary-phase acid tolerance response (ATR) was attempted by both transient low-pH acid shock and acid adaptation . For acid shock induction, strains were grown for 18 h in minimal E medium containing 0.4% glucose (EG medium) and exposed to sublethal acid stress (pH 4.3) for 2 h, and subsequently, both shocked and nonshocked cultures were acid challenged (pH 3.0) for 4 h . Acid adaptation was achieved by growing strains for 18 h in tryptic soy broth containing 1.0% glucose (TSB+G), while nonadapted cultures were grown for 18 h in glucose-free tryptic soy broth (TSB-G) . Acid-adapted and nonadapted inocula were acid challenged (pH 2.3) for 4 h . Initial (0 h) mean populations of nonchallenged Salmonella were 8.5 to 8.7, 8.4 to 8.8, and 8.2 to 8.3 log CFU/ml for strains grown in EG medium, TSB-G, and TSB+G, respectively . After 4 h of acid challenge, mean populations were 3.0 to 4.8 and 2.5 to 3.7 log CFU/ml for previously acid-shocked susceptible and resistant strains, respectively, while corresponding counts for nonshocked strains were 4.3 to 5.5 log CFU/ml and 3.9 to 4.9 log CFU/ml . Following 4 h of acid exposure, acid-adapted cultures of susceptible and resistant strains had mean populations of 6.1 to 6.4 log CFU/ml and 6.4 to 6.6 log CFU/ml, respectively, while corresponding counts for nonadapted cultures were 1.9 to 2.1 log CFU/ml and 1.8 to 2.0 log CFU/ml, respectively . A low-pH-inducible ATR was not achieved through transient acid shock, while an ATR was evident following acid adaptation, as adapted populations were 4.2 to 4.8 log units larger than nonadapted populations following acid exposure . Although some strain-dependent variations in acid resistance were observed, results from this study suggest no association between susceptibility to antimicrobial agents and the ability of the Salmonella strains evaluated to survive low-pH stress. Clin Exp Rheumatol, 2003 Mar-Apr, 21(2), 213 - 6 Prevalence of Sindbis-related (Pogosta) virus infections in patients with arthritis; Laine M et al.; OBJECTIVE: To determine the role of Pogosta virus as a triggering infection in non-specific arthritis . METHODS: Serum samples of 142 patients with acute arthritis were screened for the evidence of Pogosta virus infection . Serological tests for Chlamydia trachomatis, salmonella, parvovirus B19, and Borrelia burgdorferi were also carried out . As verified later, 78 of the patients had rheumatoid arthritis and 63 seronegative poly- or oligoarthritis, while one had systemic lupus erythematosus . RESULTS: In the early stage of the joint symptoms 4 patients with rheumatoid arthritis, 1 with seronegative polyarthritis and 1 with systemic lupus erythematosus had recent Pogosta virus infection . Four of them had probably had Pogosta disease at the time of the onset of arthritis . In 11 patients with a diagnosis of seronegative arthritis, serological evidence of preceding infection due to salmonella or Chlamydia trachomatis was found, strongly suggesting classical reactive arthritis in these cases . CONCLUSIONS: Our study suggests that also a Sindbis virus infection may be associated both to an acute joint inflammation as a part of Pogosta disease or chronic arthritis . At present, this possibility still needs further research. Avian Pathol, 2003 Feb, 32(1), 95 - 102 Functional comparison of heterophils isolated from commercial broiler chickens; Swaggerty CL et al.; Heterophils from two pure lines (A and B) of commercial broiler chickens were isolated on days 1, 4, and 7 post-hatch to evaluate their ability to (1) phagocytose Salmonella enteritidis (SE) (2) degranulate when exposed to immune-IgG opsonized SE, and (3) produce an oxidative burst . On days 1 and 4, heterophils from line A were functionally more efficient compared to heterophils from line B (p<0.05) . By 7 days post hatch, heterophil functions for both lines were comparable . To further study the inheritance of heterophil functional efficiency, F1 reciprocal crosses (line C=male Bxfemale A; line D=male Axfemale B) were evaluated for functional activity and compared with the immunologically efficient (A) and non-efficient (B) parent lines . Heterophils from line D had a more efficient heterophil function (p<0.05) when compared to heterophils from C . These results suggest that heterophil function and efficiency can be genetically transferred to progeny . Moreover they indicate that heterophil function is sex-associated and genetically controlled by the rooster since progeny of line A males maintained immunologically efficient characteristics whereas heterophils from the progeny of line B roosters remained immunologically inefficient . To our knowledge, this is the first report to describe a functional relationship between pure and F1 reciprocal crosses of broiler chickens with regard to heterophils and the innate immune response. Avian Pathol, 2003 Apr, 32(2), 193 - 203 Comparison of the immune responses against Salmonella enterica serovar Gallinarum infection between naked neck chickens and a commercial chicken line; Alvarez MT et al.; The immune responses of indigenous naked neck (NaNa and Nana) and normally feathered (nana) chickens against a Salmonella Gallinarum (SG) infection were evaluated and compared with those of a commercial line (B-380) . Groups of 28-day-old chickens (NaNa, Nana, nana, and B-380) were immunized orally and subcutaneously with 50 microg of SG antigens . Control non-immunized animals were inoculated with sterile saline solution . All chickens were challenged with 1 LD(50) of SG and mortality was recorded daily for 20 days . Antibodies to SG were measured in sera before immunization, before the challenge, 10 days after the challenge, and at sacrifice . Peripheral blood lymphocyte proliferation assays were performed using concanavalin A and SG antigens . Results showed that non-immunized Nana chickens exhibited the best natural resistance to Salmonella infection, since only 30% of them died . In contrast, all control B-380 chickens died by the 13th day . Immunization with SG induced immunity in chickens of all genotypes . Indigenous naked neck and normally feathered chickens showed a higher survival rate when compared with B-380 chickens . Immunized Nana chickens showed the highest antibody titres (P<0.05) as well as the highest thymidine incorporation in peripheral blood lymphocytes stimulated with con A or SG antigens (P<0.05) . The results show that Nana chickens are the most resistant to SG infection and the best responders to vaccination with SG antigens. J Agric Food Chem, 2003 May 21, 51(11), 3334 - 7 Protection against Trp-P-2 DNA adduct formation in C57bl6 mice by purpurin is accompanied by induction of cytochrome P450; Marczylo T et al.; Purpurin, an anthraquinone constituent from madder root, has previously been reported as antimutagenic in the Ames Salmonella bacterial mutagenicity assay and as antigenotoxic in Drosophila melanogaster, against a range of environmental carcinogens . Short-term dietary supplementation with purpurin inhibits the formation of hepatic DNA adducts in male C57bl6 mice after a single dose of the heterocyclic amine dietary carcinogen Trp-P-2 (30 mg/kg) . Inhibition of adduct formation was dose-dependent . No DNA adducts were observed in animals treated only with purpurin . The decrease in adduct formation was accompanied by significant, dose-dependent inductions of hepatic cytochrome P450-dependent dealkylations of methoxy- (CYP1A2), ethoxy- (CYP1A1), and pentoxy- (CYP2B) resorufins, total cytochrome P450, and NADPH cytochrome P450 reductase . It is hypothesized that purpurin exhibits chemopreventive potential by inhibiting the cytochrome P450-dependent metabolism of heterocyclic amines to their genotoxic N-hydroxylamines. Immunogenetics, 2003 Jun, 55(3), 133 - 40 Epub 2003 May 13. Chicken MHC class I and II gene effects on antibody response kinetics in adult chickens; Zhou H et al.; The major histocompatibility complex (MHC) plays an important role in regulation of the immune response . The MHC class I and II genes were selected as candidates to investigate associations with vaccine response to Salmonella enteritidis and kinetics of antibody response to sheep red blood cell (SRBC) and Brucella abortus . Primary antibody response after S . enteritidis vaccination at day 10, and antibody response to SRBC and killed B . abortus after immunization at 19 and 22 weeks were measured in an F2 population . The resource population was derived from males of two highly inbred MHC-congenic Fayoumi chicken lines (M5.1 and M15.2) mated with highly inbred G-B1 Leghorn line hens . Secondary phase parameters of minimum titers ( Y(min)), maximum titers ( Y(max)), and time needed to achieve Y(min) ( t(min)) and Y(max) ( t(max)) were estimated from post-secondary titers by using a non-linear regression model . Associations of single nucleotide polymorphisms (SNPs) in MHC class I and II genes with antibody response parameters were determined by a general linear model . Significant associations were found primarily in the M15.2 grandsire haplotype . There were significant associations between MHC class I alpha(1) and alpha(2) SNPs and antibody response to S . enteritidis, primary antibody response to B . abortus, Y(min) to SRBC, and Y(max) to both SRBC and B . abortus . There were significant effects of the MHC class II beta(1) domain SNP on S . enteritidis antibody and Y(max) to SRBC . The results suggest that the characterized SNPs might be used in future applications by marker-assisted selection to improve vaccine response and immunocompetence in chickens. Clin Diagn Lab Immunol, 2003 May, 10(3), 426 - 30 T- and B-cell immune responses of patients who had undergone colectomies to oral administration of Salmonella enterica serovar Typhi Ty21a vaccine; Kilhamn J et al.; The capacity of an oral live attenuated Salmonella enterica serovar Typhi Ty21a vaccine to induce immune responses in patients who had undergone colectomies because of ulcerative colitis was evaluated, and these responses were compared with those of healthy volunteers . Purified CD4(+) and CD8(+) T cells from peripheral blood were stimulated in vitro by using the heat-killed Ty21a vaccine strain, and the proliferation and gamma interferon (IFN-gamma) production were measured before and 7 or 8 days after vaccination . Salmonella-specific immunoglobulin A (IgA) and IgG antibody responses in serum along with IgA antibody responses in ileostomy fluids from the patients who had undergone colectomies were also evaluated . Three doses of vaccine given 2 days apart failed to induce proliferative T-cell responses in all the six patients who had undergone colectomies, and increases in IFN-gamma production were found only among the CD8(+) cells from three of the patients . In contrast, both proliferative responses and increased IFN-gamma production were observed among CD4(+) and CD8(+) T cells from 3 and 6 of 10 healthy volunteers, respectively . Salmonella-specific IgA and/or IgG antibody responses in serum were observed for five (56%) of nine patients who had undergone colectomies and in 15 (88%) of 17 healthy volunteers . In ileostomy fluids, significant anti-Salmonella IgA antibody titer increases were detected in six (67%) of nine patients who had undergone colectomies . The impaired T- and B-cell immune responses found after vaccination in the circulation of patients who have undergone colectomies may be explained by a diminished colonization of the Ty21a vaccine strain due to the lack of a terminal ileum and colon. Emerg Infect Dis, 2003 May, 9(5), 585 - 91 Variant Salmonella genomic island 1 antibiotic resistance gene cluster in Salmonella enterica serovar Albany; Doublet B et al.; Salmonella genomic island 1 (SGI1) contains an antibiotic resistance gene cluster and has been previously identified in multidrug-resistant Salmonella enterica serovars Typhimurium DT104, Agona, and Paratyphi B . We identified a variant SGI1 antibiotic-resistance gene cluster in a multidrug-resistant strain of S . enterica serovar Albany isolated from food fish from Thailand and imported to France . In this strain, the streptomycin resistance aadA2 gene cassette in one of the SGI1 integrons was replaced by a dfrA1 gene cassette, conferring resistance to trimethoprim and an open reading frame of unknown function . Thus, this serovar Albany strain represents the fourth S . enterica serovar in which SGI1 has been identified and the first SGI1 example where gene cassette replacement took place in one of its integron structures . The antibiotic resistance gene cluster of serovar Albany strain 7205.00 constitutes a new SGI1 variant; we propose a name of SGI1-F. Acta Vet Hung, 2003, 51(2), 137 - 51 Analysis of gene cassettes of streptomycin-spectinomycin resistance of Hungarian Salmonella enterica serotype Typhimurium strains; Nogrady N et al.; By PCR using the ant(3")-Ia primer pair the aadA gene was detected in 34 streptomycin- and spectinomycin-resistant Salmonella enterica serotype Typhimurium strains . Out of them 12 belonged to DT104 and 22 to non-DT104 phage type . Using different primer combinations it was demonstrated that this gene was integron-associated in all cases: in the DT104 strains it was generally contained by a 1 kb integron while in the majority of the non-DT104 strains by a 2.05 kb (less often by a 1.9 or 1 kb) integron . In the case of integrons carrying multiple cassettes the cassette containing the aadA gene was located closer to the 3' end of the integron . The aadA genes of DT104 and non-DT104 strains were different: in the former group the aadA2 gene, while in the latter group (constituted by strains of five different phages types as well as unclassifiable and untypable strains) the aadA1 gene could be identified . The RH50/RH51 primer pair described by Collis and Hall (1992) proved to be suitable for rapid discrimination between the aadA1 and aadA2 genes on the basis that the RH51 primer bound exclusively to the aadA2 gene. Acta Vet Hung, 2003, 51(2), 121 - 35 Integron content of Salmonella enterica serotype Typhimurium strains isolated in Hungary in the years 1997-1999; Gado I et al.; The integron content of 52 DT104/U302 phage type strains and 53 non-DT104/U302 strains of Salmonella enterica serotype Typhimurium (S . Typhimurium) was studied in PCR experiments using a 5'-CS/3'-CS primer pair (Levesque et al., 1995) . Forty-three out of 44 streptomycin- and/or ampicillin-resistant DT104 and related phage type strains were found to carry a 1 kb and/or 1.2 kb long integron . The other resistance markers did not affect the number and size of integrons; no integron-free multidrug-resistant (MDR) DT104 strains were found . The two large groups of DT104 strains (Felix-Callow's phage types 2 and 2c) proved to be identical in respect of integron patterns (IPs), supporting the views of those authors who consider DT104 a single clone . Strains of human and animal origin did not differ from each other in their IPs . Within the non-DT104 phage types, ampicillin- and/or streptomycin-resistant, integron-free MDR strains were also found . Based on amplicons varying between 290 and 3500 bp an IP system was suggested . The commonest amplicon sizes in non-DT104 strains were 1450 and 2050 bp . The IPs of DT104 strains and of non-DT104 strains containing an integron of 1 and 1.2 kb size were stable . In contrast, the IPs of other non-DT104 strains showed a varying degree of instability . Integron loss was frequently associated with spontaneous plasmid elimination and changes of R-type among the descendants of a given strain. Photochem Photobiol, 2003 Apr, 77(4), 356 - 61 Photomutagenic properties of terfenadine as revealed by a stepwise photostability, phototoxicity and photomutagenicity testing approach; Tarozzi A et al.; Administration of the second-generation antihistamine, terfenadine, is sometimes associated with photosensitivity and other skin reactions . To obtain information on its photoreactivity, we used a stepwise experimental approach involving tests for photostability, phototoxicity (PT) (mouse fibroblast cell line {3T3} neutral red uptake {NRU} test) and photomutagenicity (with standard Ames salmonella tester strains TA98, TA100 and TA102) . Terfenadine was not phototoxic to cultured mammalian cells under the conditions used (i.e . 5000/161 mJ cm(-2) UVA-UVB) . Natural sunlight and UV radiations caused considerable drug decomposition and formation of several photoproducts . Addition of the irradiated terfenadine solution (i.e . a mixture of photoproducts) to the tester did not significantly increase background mutation frequency . Irradiation of terfenadine coplated with the TA102 strain induced a clear-cut photomutagenic response, the magnitude of which was dependent upon the precursor compound concentration and the UV dose (212/7 to 339/11 mJ cm(-2) UVA-UVB) . These findings demonstrate that in vitro terfenadine is photomutagenic in absence of PT . Further in vitro and in vivo studies are therefore needed to provide an adequate safety assessment of the photochemical genotoxicity--carcinogenicity potential of terfenadine . In the meantime, patients should be advised to avoid excessive exposure to sunlight. Appl Environ Microbiol, 2003 May, 69(5), 2959 - 63 Antimicrobial effects of mustard flour and acetic acid against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica serovar Typhimurium; Rhee MS et al.; This study was designed to investigate the individual and combined effects of mustard flour and acetic acid in the inactivation of food-borne pathogenic bacteria stored at 5 and 22 degrees C . Samples were prepared to achieve various concentrations by the addition of acetic acid (0, 0.5, or 1%) along with mustard flour (0, 10, or 20%) and 2% sodium chloride (fixed amount) . Acid-adapted three-strain mixtures of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica serovar Typhimurium strains (10(6) to 10(7) CFU/ml) were inoculated separately into prepared mustard samples stored at 5 and 22 degrees C, and samples were assayed periodically . The order of bacterial resistance, assessed by the time required for the nominated populations to be reduced to undetectable levels against prepared mustards at 5 degrees C, was S . enterica serovar Typhimurium (1 day) < E . coli O157:H7 (3 days) < L . monocytogenes (9 days) . The food-borne pathogens tested were reduced much more rapidly at 22 degrees C than at 5 degrees C . There was no synergistic effect with regard to the killing of the pathogens tested with the addition of 0.5% acetic acid to the mustard flour (10 or 20%) . Mustard in combination with 0.5% acetic acid had less bactericidal activity against the pathogens tested than did mustard alone . The reduction of E . coli O157:H7 and L . monocytogenes among the combined treatments on the same storage day was generally differentiated as follows: control < mustard in combination with 0.5% acetic acid < mustard alone < mustard in combination with 1% acetic acid < acetic acid alone . Our study indicates that acidic products may limit microbial growth or survival and that the addition of small amounts of acetic acid (0.5%) to mustard can retard the reduction of E . coli O157:H7 and L . monocytogenes . These antagonistic effects may be changed if mustard is used alone or in combination with >1% acetic acid. Microb Pathog, 2003 May, 34(5), 227 - 38 Extracellular secretion of the virulence plasmid-encoded ADP-ribosyltransferase SpvB in Salmonella; Gotoh H et al.; Nontyphoid Salmonella enterica requires the plasmid-encoded spv genes to establish successful systemic infection in experimental animals . The SpvB virulence-associated protein has recently been shown to contain the ADP-ribosyltransferase domain . SpvB ADP-ribosilates actin and depolymerizes actin filaments when expressed in cultured epithelial cells . However, spontaneous secretion or release of SpvB has not been observed under in vitro growth conditions . In the present study we investigated the secretion of SpvB from Salmonella using in vitro and in vivo assay systems . We showed that SpvB is secreted into supernatant from Salmonella strains that contain the cloned spvB gene on a plasmid when they grew in intracellular salts medium (ISM), a minimal medium mimicing the intracellular iron concentrations of eukaryotic cells . A series of mutant SpvB proteins revealed that an N-terminal region of SpvB located at amino acids 1-229 was sufficient to promote secretion into extracellular milieu . Confocal immunofluorescence microscopy also demonstrated efficient localization of the N-terminal domain of SpvB(1-360) tagged with biotinylated peptide within infected host cell cytosol but not truncated SpvB(1-179) fusion protein . In addition, mutations that inactivate genes within Salmonella pathogenicity island 1 or Salmonella pathogenicity island 2 that encode type III secretion systems (TTSS) could secrete the SpvB protein into the culture medium . These results indicate that SpvB protein is transported from the bacteria and into the host cytoplasm independent of TTSS. J Microbiol Methods, 2003 Jul, 54(1), 137 - 40 Reliable determination of transposon insertion site in prokaryotes by direct sequencing; Qimron U et al.; We developed a method to identify the insertion sites of transposons in the chromosome of Salmonella using one step only . In this method, the Salmonella's genomic DNA is directly sequenced using a transposon internal primer . Reliable direct sequencing was achieved using high purity genomic DNA and an improved protocol for automated sequence machine . This note is intended to promote the use of direct sequencing, which we found to be reliable, efficient and inexpensive as compared to the other currently used methods. J Bacteriol, 2003 May, 185(10), 3111 - 7 Swarm-cell differentiation in Salmonella enterica serovar typhimurium results in elevated resistance to multiple antibiotics; Kim W et al.; Although a wealth of knowledge exists about the molecular and biochemical mechanisms governing the swimming motility of Salmonella enterica serovar Typhimurium, its surface swarming behavior has not been extensively characterized . When inoculated onto a semisolid agar medium supplemented with appropriate nutrients, serovar Typhimurium undergoes a morphological differentiation whereby single cells hyperflagellate and elongate into nonseptate, multinucleate swarm cells . Swarm migration is a collective behavior of groups of cells . We have isolated a MudJ insertion mutant of serovar Typhimurium 14028 that failed to swarm under any conditions . The site of the MudJ insertion was determined to be in the pmrK locus within the pmrHFIJKLM operon, which was previously demonstrated to confer resistance to cationic antimicrobial peptides . beta-Galactosidase assays, using the pmrK::lacZ transcriptional fusion, showed increased expression of the pmr operon in swarm cells compared to that in vegetative cells . In concurrence with the expression data, swarm cells exhibited greater tolerance to polymyxin . To compare the profiles of vegetative and swarm-cell resistance to other antibiotics, E-test strips representing a wide range of antibiotic classes were used . Swarm cells exhibited elevated resistance to a variety of antibiotics, including those that target the cell envelope, protein translation, DNA replication, and transcription . These observations, in addition to the dramatic morphological changes associated with the swarming phenotype, provide an intriguing model for examining global differences between the physiological states of vegetative and swarm cells of serovar Typhimurium. Chemosphere, 2003 Jul, 52(1), 277 - 81 Bactericidal effect of TiO2 photocatalyst on selected food-borne pathogenic bacteria; Kim B et al.; Titanium dioxide (TiO(2)) photocatalysts have attracted great attention as a material for photocatalytic sterilization in the food and environmental industry . This research aimed to design a new photobioreactor and its application to sterilize selected food borne pathogenic bacteria, Salmonella choleraesuis subsp., Vibrio parahaemolyticus, and Listeria monocytogenes . The photocatalytic reaction was carried out with various TiO(2) concentrations and Ultraviolet (UV) illumination time . A feasible synergistic effect was found that the bactericidal effect of TiO(2) on all bacterial suspension after UV light irradiation was much higher than that of without TiO(2) . As the concentration of TiO(2) increased to 1.0 mg/ml, bactericidal effect increased . However, the bactericidal effect was rapidly abbreviated at TiO(2) concentration higher than 1.25 mg/ml to all selected bacteria . UV illumination time affected drastically the viability of all bacteria with different death rate . Similar trends were obtained from S . choleraesuis subsp . and V . parahaemolyticus that their complete killing was achieved after 3 h of illumination . However, L . monocytogenes was more resistant and its death ratio was about 87% at that time. Epidemiol Infect, 2003 Apr, 130(2), 169 - 78 A national outbreak of multi-resistant Salmonella enterica serovar Typhimurium definitive phage type (DT) 104 associated with consumption of lettuce; Horby PW et al.; Between 1 August and 15 September 2000, 361 cases of Salmonella enterica serotype Typhimurium definitive phage type (DT) 104, resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, spectinomycin and tetracycline (R-type ACSSuSpT), were identified in England and Wales residents . Molecular typing of 258 isolates of S . Typhimurium DT104 R-type ACSSuSpT showed that, although isolates were indistinguishable by pulsed-field gel electrophoresis, 67% (174/258) were characterized by a particular plasmid profile . A statistically significant association between illness and consumption of lettuce away from home was demonstrated (OR = 7.28; 95% CI=2.25-23.57; P=0.0006) in an unmatched case-control study . Environmental investigations revealed that a number of food outlets implicated in the outbreak had common suppliers of salad vegetables . No implicated foods were available for microbiological testing . An environmental audit of three farms that might have supplied salad vegetables to the implicated outlets did not reveal any unsafe agricultural practices . The complexity of the food supply chain and the lack of identifying markers on salad stuffs made tracking salad vegetables back to their origin extremely difficult in most instances . This has implications for public health since food hazard warnings and product withdrawal are contingent on accurate identification of the suspect product. Yonsei Med J, 2003 Apr 30, 44(2), 198 - 202 A food-borne outbreak caused by Salmonella enteritidis; Tansel O et al.; This study was designed to define the epidemiology of a food-borne outbreak caused by Salmonella enteritidis that affected only one squadron of a military battalion located in the vicinity of the city of Edirne in Turkey . The outbreak was analyzed by a standard surveillance form of the Centers for Disease Control and Prevention . The relationship between the eaten foods and cases was analyzed by Fisher's exact chi-square test, and odds ratios were calculated by a case-control study . The outbreak affected 60 of 168 soldiers in the squadron, 16 of whom were hospitalized . S.enteritidis was cultured in stools from 13 of the hospitalized soldiers and from 3 soldiers who had prepared the food . All strains were completely susceptible to antibiotics; their plasmid profiles were also identical . The highest attack rate detected was 55.7% in an omelet eaten 24 hours before (p < 0.001) . Furthermore, it was the riskiest food according to the case-control study (OR=7.88; 95% CI=3.68-16.89) . The food samples were unobtainable because they had been discarded . All of the hospitalized cases recovered, and none of the control cultures of stools yielded the pathogen after three weeks . In conclusion, although our results didn't indicate the exact source of the outbreak microbiologically, the omelet was considered to be the source based on the epidemiological proofs. Intensive Care Med, 2003 Jun, 29(6), 989 - 94 Epub 2003 May 01. Nicotinamide increases systemic vascular resistance in ovine endotoxemia; Scharte M et al.; OBJECTIVE: The nuclear enzyme Poly(ADP-Ribose)-Polymerase (PARP) has been hypothesized as playing a major role in various forms of inflammation . PARP activation is induced by DNA strand breakage and can result in intracellular energy depletion and, ultimately, cell death . Further, it is thought to influence cardiovascular function and organ failure in endotoxemia . Here, we investigated the effect of the PARP inhibitor nicotinamide on cardiovascular and liver function in healthy and chronically endotoxemic sheep . DESIGN: Prospective controlled trial . SETTING: University research laboratory . Subjects: 12 female adult sheep . INTERVENTIONS: Six healthy sheep, instrumented for chronic study, received nicotinamide intravenously as a bolus of 40 mg/kg followed by a continuous infusion of 10 mg.kg(-1).h(-1); six animals received the vehicle . One hour after bolus application, a continuous infusion of endotoxin ( Salmonella typhosa, 10 ng.kg(-1).min(-1)) was started . Hemodynamic parameters were determined before and during endotoxemia . MEASUREMENTS AND RESULTS: Treatment with nicotinamide resulted in a significantly higher systemic vascular resistance index and lower cardiac index in endotoxemic animals, but not in controls . It also attenuated endotoxin-induced increase in gamma-glutamyl transferase . CONCLUSIONS: The PARP inhibitor nicotinamide attenuates impairment of cardiovascular function during endotoxemia . In addition, PARP activation may be involved in endotoxin-induced liver injury. Infez Med, 1999, 7(1), 49 - 53 Salmonella typhi disease in HIV-infected patients: case reports and literature review; Manfredi R et al.; Two patients with AIDS and severe immunodeficiency developed typhoid fever . The diagnosis was confirmed by isolation of Salmonella typhi from blood cultures, while Widal's serum test isolates proved in vitro sensitive to all tested antimicrobial agents, and complete recovery was obtained with i.v . cotrimoxazole and piperacillin treatment . Unlike complications by non-tiphoid Salmonellae, S . typhi infection has been infrequently reported in the context of AIDS: to our knowledge, only five cases of typhoid fever have been described in HIV-infected living industrialized countries . Medical history and epidemiological information may play an important role in prompting the search for an S . typhi infection in patients coming from endemic regions, since most of the sign and symptoms of typhoid fever may mimic those of a sepsis . Or other AIDS-related complications Comp Biochem Physiol A Mol Integr Physiol, 2003 May, 135(1), 177 - 84 Inflammatory agonist stimulation and signal pathway of oxidative burst in neonatal chicken heterophils; He H et al.; Heterophils are the predominant polymorphonuclear leukocytes (PMNs) in poultry . The oxidative burst of activated heterophils, which generates reactive oxygen species (ROS), is one of the first line cellular defenses against invading microorganisms . In this report, the oxidative response of heterophils from neonatal chicks to in vitro stimulation by various inflammatory agonists was investigated using a fluorescence microplate assay . Both non-opsonized formalin-killed Salmonella enteritidis and Staphylococcus aureus were able to stimulate heterophil oxidative burst . The phorbol myristate acetate (PMA) was the most potent stimulant for the chicken heterophil oxidative response, whereas, the bacterial cell surface components lipopolysaccharide (LPS) and lipoteichoic acid (LTA) were less effective . Protein kinase C (PKC) is an essential signaling component regulating heterophil oxidative response to stimulation by PMA, LPS, LTA and S . enteritidis . However, inhibition of PKC did not affect the oxidative response to stimulation by S . aureus, suggesting differential signaling pathway responsible for the activation of oxidative burst by Gram-negative S . enteritidis and Gram-positive S . aureus . Inhibition of mitogen activated protein (MAP) kinase p38 and extracellular response kinase (ERK) by SB 203580 and PD 098059, respectively, did not inhibit activated oxidative burst. Wei Sheng Yan Jiu, 2000 Mar 30, 29(2), 120 - 2 {Effect of irradiation on the shelf-life of aquatic products}; Cui S et al.; The effect of irradiation at doses of 0-10 kGy on the shelf-life of aquatic products was determined . The results showed that irradiation could not prolong the shelf-life of aquatic products kept at 25 degrees C . While the aquatic products were kept at refrigerator (4 degrees C), the irradiation could prolong the shelf-life and effectively reduce the total aerobic plate count . Irradiation could effectively reduce the number of coliform to less than 300/kg and eliminate Shigella shigae, Salmonella and Vibrio parahaemolyticus inoculated on shrimp, needle fish and crucian . A dose of 2.5 kGy could delay the rising of total volatile basal nitrogen in samples. Microbiology, 2003 May, 149(Pt 5), 1103 - 11 SseA is a chaperone for the SseB and SseD translocon components of the Salmonella pathogenicity-island-2-encoded type III secretion system; Ruiz-Albert J et al.; The type III secretion system (TTSS) encoded by the Salmonella pathogenicity island 2 (SPI-2) is required for bacterial replication inside macrophages and for systemic infection in mice . Many TTSS secreted proteins, including effectors and components of the translocon, require chaperones which promote their stability, prevent their premature interactions or facilitate their secretion . In this study, the function of the first gene (sseA) of one of the SPI-2 operons (sseA-G) was investigated . This operon includes genes that encode translocon components (SseB, SseC and SseD), translocated proteins (SseF and SseG) and putative chaperones (SscA and SscB) . sseA encodes a 12.5 kDa protein with a C-terminal region with the potential to form a coiled-coil structure, but no sequence similarity to other proteins . Mutation of sseA results in severe virulence attenuation and an intracellular replication defect . It is shown here that SseA is not a secreted protein, but is required for SPI-2-dependent translocation of two effector proteins (SifA and PipB) . Furthermore, the translocon components SseB and SseD were not detected in an sseA mutant strain . By using a yeast two-hybrid assay and column binding experiments, it is demonstrated that SseA interacts directly with SseB and SseD . These results indicate that SseA is a chaperone for SseB and SseD . The inability of an sseA mutant to assemble the SPI-2 TTSS translocon accounts for its high level of virulence attenuation in vivo . To the authors' knowledge, this is the first chaperone described for the SPI-2 TTSS. J AOAC Int, 2003 Mar-Apr, 86(2), 275 - 95 Detection of Salmonella in fresh cheese, poultry products, and dried egg products by the ISO 6579 Salmonella culture procedure and the AOAC official method: collaborative study; Feldsine PT et al.; Three food types were analyzed for the presence of Salmonella by the AOAC culture method and by the International Organization for Standardization (ISO 6579:2002) culture method . Paired test portions of each food type were simultaneously analyzed by both methods . A total of 21 laboratories representing federal government agencies and private industry, in the United States and Europe, participated in this interlaboratory study . Foods were artificially contaminated with Salmonella and competing microflora if naturally contaminated sources were not available . No statistical differences (p < 0.05) were observed between the AOAC and ISO culture methods for fresh cheese and dried egg products . A statistically significant difference was observed for one of the 2 lots of poultry from the first trial . The poultry meat used in this run was radiation sterilized, artificially contaminated with Salmonella and competitive flora, and then lyophilized . A second trial was conducted with 2 separate lots of raw ground chicken that were naturally contaminated . The results from the second trial showed no statistical difference between the 2 culture methods . A third trial involving 4 laboratories was conducted on 2 separate lots of naturally contaminated raw poultry . Again, no statistically significant differences occurred . It is recommended that ISO 6579:2002 culture method for Salmonella be adopted Official First Action for the analysis of fresh cheese, fresh chilled and frozen poultry, and dried egg products. Immunol Invest, 2003 Feb, 32(1-2), 3 - 15 Poly(ethyleneimine)-immobilized-cloth enzyme immunoassay for the detection of Salmonella lipopolysaccharide; Matsumoto K et al.; Poly(ethyleneimine) (PEI) was immobilized on non-woven polyester cloth and examined for application on a simple, rapid and economical "cloth enzyme immunoassay (CEIA)" which was developed originally as polymyxin-CEIA for the detection of Salmonella lipopolysaccharide (LPS) . PEI-cloth regardless of the PEI molecular weight, but with the amine group contents of 0.1 to approximately 0.35 meq/g immobilized either in a physisorption-like or chemisorption-like manner, adsorbed LPS rapidly, preferentially and effectively . The captured LPS was then able to be detected qualitatively and quantitatively as an antigen by enzyme immunoassay . PEI-CEIA had a detection limit for Salmonella LPS of 10 ng/ml, which was equivalent to 1.6 x 10(5) cell/ml and was ten times more sensitive than polymyxin-CEIA . It was possible to detect Salmonella LPS in the presence of a 100-fold excess of E . coli LPS . PEI-CEIA was found to be more sensitive and much easier to carry out than polymyxin-CEIA but had the same advantages as polymyxin-CEIA. Phytother Res, 2003 Apr, 17(4), 325 - 9 Antibacterial, antiprotozoal and antioxidant activity of five plants used in Izabal for infectious diseases; Navarro MC et al.; Methanol and aqueous extracts from fi ve plant species, used in traditional medicine in Guatemala for the treatment of microbial infections, were tested in vitro for their ability to scavenge DPPH, OH(.) and O(2) (-) radicals and to inhibit lipoperoxidation (LPO) in order to establish a relationship between their antioxidant activities and their effects against infectious agents . Acalypha guatemalensis, Ocimum micranthum and Smilax spinosa possessed a significant activity against both the three free radicals assayed and LPO; Guazuma ulmifolia showed effects against DPPH and OH(.) . Piper auritum showed no activity . These extracts were also evaluated for antibacterial and antiprotozoal activities . A . guatemalensis showed activity against Pseudomonas aeruginosa; S . spinosa was active against Salmonella typhi, and A . guatemalensis, and S . spinosa against Trypanosoma cruzi or Leishmania spp . Pediatr Surg Int, 2003 Apr, 19(1-2), 65 - 7 Epub 2003 Jan 17. Acalculous cholecystitis in Nigerian children; Chirdan LB et al.; Sixteen children with acalculous cholecystitis (AC) were treated over a 9-year period (13 male and 3 female) . Their ages ranged from 8 to 18 years (median 11) . Eight (50%) presented with complications (perforation 4, gangrene 2, empyema 2); 13 (80%) presented with acute AC with a duration of symptoms of 2 weeks or less while 3 (20%) presented with chronic AC with symptoms present for more than 3 months . The diagnosis was made by ultrasound except in the patients with complications, who were diagnosed at laparotomy . Salmonella typhi was cultured in the bile and blood in 2 cases and the Widal titre was significantly elevated in 4 others . One child had chronic blockage of the cystic duct by a lymph node; in 9 there was no identifiable cause . Open cholecystectomy was successfully performed in 15 cases, while 1 child was managed non-operatively . The need for early diagnosis of cholecystitis in children is obvious if the potentially life-threatening complications of perforation and gangrene are to be avoided. J Agric Food Chem, 2003 May 7, 51(10), 2958 - 63 Application of hexanal, E-2-hexenal, and hexyl acetate to improve the safety of fresh-sliced apples; Lanciotti R et al.; The aims of this work were to evaluate the effects of different concentrations of hexanal, (E)-2-hexenal, hexyl acetate, and their mixtures on the fate of pathogenic species such as Escherichia coli, Salmonella enteritidis, and Listeria monocytogenes inoculated in model systems as well as the antimicrobial activity against the target species of the chosen molecules when added to the packaging atmosphere of inoculated fresh-sliced apples . The result obtained in this work pointed out the potential use of compounds such as hexanal, (E)-2-hexenal, and hexyl acetate for both the extension of shelf life and an improvement of hygienic safety of "minimally processed foods" . In fact, hexanal, (E)-2-hexenal, and hexyl acetate had a significant inhibitory effect against pathogen microorganisms frequently isolated from raw materials (E . coli, S . enteritidis, and L . monocytogenes) when inoculated in both model and real systems . In this last condition, these compounds, at the levels used (150, 150, and 20 ppm for hexanal, hexyl acetate, and (E)-2-hexenal, respectively), displayed a bactericide effect on L . monocytogenes and they exhibited significant extensions of lag phase of E . coli and S . enteritidis inoculated at levels of 10(4)-10(5) CFU/g. Prev Vet Med, 2003 May 30, 59(1-2), 27 - 42 A decision-support system for Salmonella in broiler-chicken flocks; Rose N et al.; We built a decision-support system to assess the risk of contamination of chicken-broiler flocks by Salmonella at the end of the rearing period . This system was developed from the survey data from 85 chicken-broiler flocks located in western France . First, we estimated the probability of contamination of the house by Salmonella before placement of day-old chicks via a cleansing inspection using a visual-inspection grid, a decontamination evaluation using count-plates, and risk factors for Salmonella persistence in the barn after cleansing and disinfection . Second, we estimated (using a logistic model) the probability of prevalent contamination of the flock by Salmonella at the end of the rearing period . Validation was carried out on 60 flocks selected from seven production companies in western France . The risk estimated by the model was compared to the Salmonella status of the flock (gold standard) assessed by samples taken from the environment of the broilers and analysed with classical bacteriological methods . The sensitivity was 97.8% and the specificity 64.3%. Int J Infect Dis, 2002 Sep, 6(3), 187 - 90 Risk factors for mortality caused by nontyphoidal Salmonella sp . in children; Rosanova MT et al.; OBJECTIVE: To identify the risk factors for mortality in extraintestinal nontyphoidal Salmonella (NTS) infections in infants and children . METHODS: We performed a retrospective analysis of 107 patients with at least one nonfecal culture for NTS seen from January 1988 to December 1995 . RESULTS: The median age was 12 (range 1-216) months . Malnutrition was found in 55 patients (51%), and 22 (20%) displayed severe features (weight loss >40%) . Seventy-two patients (67%) had previously been hospitalized, and 59 (55%) had received antibiotics during the month before admission . Fever (85%) and diarrhea (56%) were the most frequent clinical manifestations . Nineteen children (18%) had leukopenia . Forty-nine patients (46%) had only bacteremia, 33 (31%) bacteremia with focal infections, and 25 (23%) focal infections with negative blood cultures . Forty-seven strains (44%) were multiresistant, and 40 of them were nosocomially acquired . Eight patients (7%) had received inappropriate antibiotic treatment, and two of them died . Thirteen (12%) children died . Age, underlying disease, previous admission, previous antibiotic therapy, type of infection, susceptibility of the strains and inappropriate antibiotic treatment were not statistically significant risk factors for mortality . A logistic regression analysis selected the following variables as independently influencing outcome: malnutrition (P<0.01), leukopenia (P<0.002) and presence of diarrhea (P<0.02) . CONCLUSIONS: Children with extraintestinal infections by NTS with leukopenia, malnutrition and presence of diarrhea have a higher risk of death. Asian Pac J Cancer Prev, 2003 Jan-Mar, 4(1), 31 - 8 Mutagenicity of the drinking water supply in Bangkok; Kusamran WR et al.; Seventeen samples of tap water in Bangkok and 2 neighboring provinces were collected in winter and summer, concentrated and tested for mutagenic activity using the Ames Salmonella mutagenesis assay . Preliminary results demonstrated that concentrated tap water exhibited clear mutagenicity towards S . typhimurium TA100 and YG1029, but not towards TA98 and YG1024, in the absence of S9 mix, and the addition of S9 mix markedly decreased the mutagenicity to both tester strains . Amberlite( ) XAD-2 resin, but not blue rayon, was able to adsorb mutagens from water at pH 2 . Our data clearly demonstrated that all tap water samples prepared by chlorination of Chao Phraya River water were mutagenic to strain TA100 without S9 mix, inducing 3,351 + 741 and 2,216 + 770 revertants/l, in winter and summer, respectively . On the other hand, however, tap water samples prepared from ground water were not mutagenic . Furthermore, it was found that boiling for only 5 min and filtration through home purifying system containing activated charcoal and mixed resin units were very effective to abolish the mutagenicity of water . Storage of water also significantly decreased the mutagenicity, however, it took 2-3 weeks to totally abolish it . Additionally, we also found 1 out of 6 brands of commercially available bottled drinking water to be mutagenic, with about 26 % of the average mutagenicity of tap water . The results in the present study clearly demonstrated that chlorinated tap water in Bangkok and neighboring provinces contain direct-acting mutagens causing capable of causing base-pair substitution . Boiling and filtration of tap water through home purifying systems may be the most effective means to abolish the mutagenicity . Some brands of commercial bottled waters may also contain mutagens which may be derived from tap water. Chemotherapy, 2003 May, 49(1-2), 49 - 55 Intracellular activity of fosfomycin against two distinct enteropathogenic bacteria, Salmonella enterica and Listeria monocytogenes, alive inside host cells; Okada N et al.; We studied the effect of fosfomycin (FOM) on the intracellular growth of two different facultative intracellular bacteria, Salmonella enterica serovar Typhimurium and Listeria monocytogenes, in an enterocyte-like cell line, Caco-(2) . These bacteria replicate in different compartments within the host cells; Salmonella serovar Typhimurium grow inside phagosomes, whereas L . monocytogenes escape the phagosomal environment and multiply in the cytosol of the host cells . At concentrations equal to 0.25 of the MIC and 4 times the MIC, respectively, FOM effectively decreased the number of intracellular Salmonella serovar Typhimurium . Although FOM was ineffective at inhibiting the extracellular growth of L . monocytogenes in vitro, this antibiotic induced a marked reduction in intracellular L . monocytogenes, indicating that, comparatively, FOM may be more effectively taken up by L . monocytogenes in the intracellular environment . Cell Microbiol, 2003 May, 5(5), 299 - 313 Genetic control of susceptibility to bacterial infections in mouse models; Lam-Yuk-Tseung S et al.; Historically, the laboratory mouse (Mus musculus) has been the experimental model of choice to study pathophysiology of infection with bacterial pathogens, including natural and acquired host defence mechanisms . Inbred mouse strains differ significantly in their degree of susceptibility to infection with various human pathogens such as Mycobacterium, Salmonella, Legionella and many others . Segregation analyses and linkage studies have indicated that some of these differences are under simple genetic control whereas others behave as complex traits . Major advances in genome technologies have greatly facilitated positional cloning of single gene effects . Thus, a number of genes playing a key role in initial susceptibility, progression and outcome of infection have been uncovered and the functional characterization of the encoded proteins has provided new insight into the molecular basis of antimicrobial defences of polymorphonuclear leukocytes, macrophages, as well as T and B lymphocytes . The multigenic control of susceptibility to infection with certain human pathogens is beginning to be characterized by quantitative trait locus mapping in genome wide scans . This review summarizes recent progress on the mapping, cloning and characterization of genes and proteins that affect susceptibility to infection with major intracellular bacterial pathogens. Cell Microbiol, 2003 May, 5(5), 287 - 97 Role of lipid-mediated signal transduction in bacterial internalization; Brumell JH et al.; Receptor-mediated phagocytosis normally represents an important first line of immune defence . Invading microbes are internalized into phagosomes and are typically killed by exposure to a battery of microbicidal agents . To some intracellular pathogens, however, receptor-mediated phagocytosis represents an opportunity to access a protected niche within the host cell . Another type of intracellular pathogen, including Salmonella enterica serovar Typhimurium and Shigella flexneri, invade host cells in a more direct manner . These pathogens deliver effectors into the host cell via a type III secretion apparatus, initiating a ruffling response that leads to their uptake into intracellular vacuoles . Recent studies have demonstrated the importance of lipid signal transduction events in the uptake of pathogenic bacteria by both receptor-mediated phagocytosis and type III secretion-mediated invasion . In this review we highlight some of these discoveries, with a focus on phospholipid-dependent signalling events. Avian Dis, 2003 Jan-Mar, 47(1), 163 - 8 Low persistence of a large-plasmid-cured variant of Salmonella enteritidis in ceca of chicks; Virlogeux-Payant I et al.; In order to estimate the contribution of Salmonella in the persistence of this bacterium in chicks, we compared the persistence of a Salmonella enteritidis strain and its plasmid-cured variant in a chicken asymptomatic carrier state model . After oral inoculation, colonization with the plasmid-cured strain was significantly reduced (P < 0.001) in the ceca of chicks from the third week postinoculation and persisted for a shorter period than the wild-type strain . Moreover, numbers of S . enteriditis-infected livers were also significantly lower (P < 0.01) for the plasmid-cured strain compared with the wild-type strain from the third to the seventh week postinoculation . No difference in spleen colonization was observed . These results did not correlate with any in vitro difference in attachment, entry to, or intracellular multiplication of bacteria within intestinal or macrophage avian cell lines. Avian Dis, 2003 Jan-Mar, 47(1), 143 - 8 The role of disinfectant resistance of Salmonella enterica serotype enteritidis in recurring infections in Pennsylvania egg quality assurance program monitored flocks; Davison S et al.; The Pennsylvania egg quality assurance program (PEQAP) has made major gains in the reduction of Salmonella enterica serotype enteritidis (S . enteritidis) . However, S . enteritidis continues to be a major food safety concern for the commercial egg laying industry . Despite intensive control efforts through PEQAP, some commercial egg layer houses still remain positive for S . enteritidis . The primary objective of this study was to determine whether S . enteritidis isolates obtained from historically environmentally S . enteritidis-positive houses were resistant to commonly used disinfectants . Archived S . enteritidis isolates (environmental, rodent, or egg) were compared with recently obtained isolates from the environment, rodents, or eggs from the same S . enteritidis-positive house . In addition, the isolates were compared with archived isolates from those premises that appeared to have eliminated S . enteritidis from their layer facilities . The official methods of the use-dilution analysis of the Association of Official Analytical Chemists were used to evaluate each disinfectant product . Two phenolic, one quaternary ammonium, and one combination product containing quaternary ammonium and formaldehyde were evaluated, in addition to one sodium hypochlorite detergent . All products diluted according to the manufacturers' recommendations killed the S . enteritidis isolates in this test system . There was no difference in susceptibility or resistance to the disinfectants used between the isolates from those facilities that remained S . enteritidis-positive and those that appeared to have eliminated S . enteritidis from their facility. Avian Dis, 2003 Jan-Mar, 47(1), 134 - 42 Salmonella enterica serotype enteritidis in table egg layer house environments and in mice in U.S . layer houses and associated risk factors; Garber L et al.; Prevalence was estimated for Salmonella enterica serotype eneritidis (SE) in layer house environments (n = 200 layer houses) and house mice (n = 129 layer houses) in 15 states throughout the United States . Environmental swabs were collected from manure, egg belts, elevators, and walkways . Live-catch rodent traps were placed for 4-7 days . Swabs and house mice were submitted to the laboratory for bacterial culture . Overall, 7.1% of layer houses and 3.7% of mice were culture positive for SE . The highest prevalence was in the Great Lakes region of the United States, and no SE was recovered from houses or mice in the southeast region . Presence of SE in layer houses was associated with age/molting, floor reared pullets, and number of rodents trapped . Cleaning and disinfecting houses between flocks was associated with a reduced risk . The prevalence of SE in mice from environmentally positive houses was nearly four times that of mice from environmentally negative houses. Zh Mikrobiol Epidemiol Immunobiol, 2000 Jul-Aug, (4 Suppl), 7 - 11 {Mechanisms of activation of pathogenic bacteria in the host organism}; Romanova IuM et al.; A minireview of the data of literature on the interaction of bacteria with cytokins and the stimulation of the growth of pathogenic bacteria by some cytokins is presented . The addition of tumor necrosis factor-alpha into the culture medium has been shown to stimulate the growth of Salmonella virulent and avirulent strains 4-fold and 2-fold respectively . This cytokin has also been shown to produce a stimulating effect on the process of the in vitro and in vivo recultivation of noncultivating forms of virulent and avirulent strains. Proc Natl Acad Sci U S A, 2003 May 13, 100(10), 6127 - 32 Epub 2003 Apr 23. Iron chelators modulate the fusogenic properties of Salmonella-containing phagosomes; Jabado N et al.; In macrophages, the divalent cations transporter Nramp1 is recruited from the lysosomal compartment to the membrane of phagosomes formed in these cells . Nramp1 mutations cause susceptibility to infection with intracellular pathogens such as Salmonella and Mycobacterium . Intracellular survival of Salmonella involves segregation in an endomembrane compartment (Salmonella-containing vacuole, SCV) that remains negative for the mannose-6-phosphate receptor (M6PR) and that is inaccessible to the endocytic pathway . Expression of Nramp1 at the membrane of SCVs stimulates both acquisition of M6PR and accessibility to newly formed endosomes . The possible role of Nramp1-mediated iron transport on SCV maturation was investigated with membrane-permeant iron chelators . Pretreatment of primary macrophages from Nramp1 mutant mice or of RAW264.7 macrophages (from BALBc mice bearing an Nramp1(D169)-deficient allele) with either desferrioxamine or salicylaldehyde isocotinoyl hydrazone restored recruitment of M6PR and delivery of the fluid phase marker rhodamine dextran to SCVs to levels similar to those seen in macrophages expressing WT Nramp1 . The effect was specific and dose-dependent and could be abrogated by preincubation with excess iron . These data suggest that Nramp1-mediated deprivation of iron and possibly of other divalent metals in macrophages antagonizes the ability of Salmonella to alter phagosome maturation. J Vet Med B Infect Dis Vet Public Health, 2003 Feb, 50(1), 38 - 41 Investigations into possible alternative decontamination methods for Salmonella enteritidis on the surface of table eggs; Davies RH et al.; Investigations into various alternative techniques for decontamination of the surfaces of artificially contaminated shell eggs were carried out . Ionized air, exposure to ozone in a dry atmosphere and use of a commercial herbal antibacterial product were not effective . Application of ozone in a humid environment was only partially effective but a commercial ionized water anolyte was highly effective in eliminating Salmonella from egg surfaces. Poult Sci, 2003 Apr, 82(4), 687 - 90 Detection of Salmonella enteritidis in incubated pools of egg contents by fluorescence polarization and lateral flow immunodiffusion; Gast RK et al.; Efficient detection of Salmonella enteritidis inside eggs is critical for confirming that individual commercial laying flocks present a risk to public health . In most standard bacteriological culturing protocols, an initial incubation step is necessary to allow the typically very small population of S . enteritidis cells in pools of egg contents to multiply to more easily detectable levels . In the present study, two rapid methods were evaluated as alternatives to plating on selective media for detecting S . enteritidis in incubated egg pools . By using either fluorescence polarization or lateral flow immunodiffusion assays, S . enteritidis could be consistently detected in egg pools at 10(8) cfu/mL (and in most pools at 10(7) cfu/mL) . Although the rapid assays were significantly less sensitive than culturing, they both were consistently able to detect contamination when pools of 10 eggs were inoculated with approximately 10 cfu of S . enteritidis and incubated for 72 h at 25 degrees C. Antimicrob Agents Chemother, 2003 May, 47(5), 1727 - 31 Persistence of Salmonellae in blood and bone marrow: randomized controlled trial comparing ciprofloxacin and chloramphenicol treatments against enteric fever; Gasem MH et al.; We performed a randomized controlled trial involving 55 adult patients with enteric fever to compare ciprofloxacin and chloramphenicol . Blood and bone marrow cultures and cytokine profiles during therapy were done to compare the clinical and bacteriological efficacies of these drugs . All patients were randomly assigned to receive chloramphenicol (500 mg four times a day orally) for 14 days or ciprofloxacin (500 mg twice a day orally) for 7 days . In each treatment group, patients were subsequently randomized to have blood and bone marrow cultured after either 3 or 5 days of treatment . Twenty-seven patients received chloramphenicol, and 28 received ciprofloxacin . The two groups were similar in terms of baseline characteristics . No significant differences in clinical cure and time to defervescence were found . All strains isolated were susceptible to both antibiotics . Although ciprofloxacin was more effective in the elimination of Salmonella enterica serovars Typhi and Paratyphi A from bone marrow than chloramphenicol, there was still an impressive persistence of Salmonella in the bone marrow culture (67%) . In the ciprofloxacin-treated patients the suppressed cytokine production capacity showed a trend to normalize earlier than in patients treated with chloramphenicol. J Mol Biol, 2003 May 2, 328(3), 609 - 21 Crystal structure of 2-methylisocitrate lyase (PrpB) from Escherichia coli and modelling of its ligand bound active centre; Grimm C et al.; Following acetate, propionate is the second most abundant low molecular mass carbon compound found in soil . Many microorganisms, including most, if not all fungi, as well as several aerobic bacteria, such as Escherichia coli and Salmonella enterica oxidize propionate via the methylcitrate cycle . The enzyme 2-methylisocitrate lyase (PrpB) from Escherichia coli catalysing the last step of this cycle, the cleavage of 2-methylisocitrate to pyruvate and succinate, was crystallised and its structure determined to a resolution of 1.9A . The enzyme, which strictly depends on Mg(2+) for catalysis, belongs to the isocitrate lyase protein family . A common feature of members of this enzyme family is the movement of a so-called "active site loop" from an open into a closed conformation upon substrate binding thus shielding the reactants from the surrounding solvent . Since in the presented structure, PrpB contains, apart from a Mg(2+), no ligand, the active site loop is found in an open conformation . This conformation, however, differs significantly from the open conformation present in the so far known structures of ligand-free isocitrate lyases . A possible impact of this observation with respect to the different responses of isocitrate lyases and PrpB upon treatment with the common inhibitor 3-bromopyruvate is discussed . Based on the structure of ligand-bound isocitrate lyase from Mycobacterium tuberculosis a model of the substrate-bound PrpB enzyme in its closed conformation was created which provides hints towards the substrate specificity of this enzyme. Biosens Bioelectron, 2003 May, 18(5-6), 813 - 9 A conductometric biosensor for biosecurity; Muhammad-Tahir Z et al.; The paper describes the development of a conductometric biosensor for detecting foodborne pathogens . The biosensor consists of two components: an immunosensor that is based on electrochemical sandwich immunoassay, and a reader for signal measurement . The architecture of the immunosensor utilizes a lateral flow system that allows the liquid sample to move from one pad to another . The biosensor provides a specific, sensitive, low volume, and near real-time detection mechanism . Results are presented to highlight the performance of the biosensor for enterohemorrhagic Escherichia coli O157:H7 and Salmonella spp., which are of concern to biosecurity . The lower limit of detection is approximately 7.9 x 10(1) colony forming units per milliliter within a 10-min process . The ability to change the specificity of the antibodies will enable the biosensor to be used as a detection device for other types of foodborne pathogens. Res Microbiol, 2003 Apr, 154(3), 173 - 4 Supplement 2001 (no . 45) to the Kauffmann-White scheme; Popoff MY et al.; This supplement reports the characterization of 22 new Salmonella serovars recognized in 2001 by the WHO Collaborating Centre for Reference and Research on SALMONELLA: 14 were assigned to S . enterica subspecies enterica, 2 to subspecies salamae, 1 to subspecies arizonae, 4 to subspecies diarizonae and 1 to subspecies indica. Infect Immun, 2003 May, 71(5), 2885 - 91 Coordinate regulation of Salmonella enterica serovar Typhimurium invasion of epithelial cells by the Arp2/3 complex and Rho GTPases; Criss AK et al.; Salmonella enterica serovar Typhimurium can infect epithelial cells via the basolateral surface after breaching the intestinal epithelium, yet little is known about this process . Here, we show that actin polymerization driven by the Arp2/3 complex is critical to both basolateral and apical bacterial invasion of polarized MDCK cells . While there is also a dependence upon toxin B-sensitive Rho GTPases, none of the four GTPases known to be activated by S . enterica serovar Typhimurium SopE are individually required for basolateral internalization . These results underscore that the specific factors required for Salmonella invasion differ between membrane domains of polarized epithelia. Infect Immun, 2003 May, 71(5), 2839 - 58 Pretreatment of mice with streptomycin provides a Salmonella enterica serovar Typhimurium colitis model that allows analysis of both pathogen and host; Barthel M et al.; Salmonella enterica subspecies 1 serovar Typhimurium is a principal cause of human enterocolitis . For unknown reasons, in mice serovar Typhimurium does not provoke intestinal inflammation but rather targets the gut-associated lymphatic tissues and causes a systemic typhoid-like infection . The lack of a suitable murine model has limited the analysis of the pathogenetic mechanisms of intestinal salmonellosis . We describe here how streptomycin-pretreated mice provide a mouse model for serovar Typhimurium colitis . Serovar Typhimurium colitis in streptomycin-pretreated mice resembles many aspects of the human infection, including epithelial ulceration, edema, induction of intercellular adhesion molecule 1, and massive infiltration of PMN/CD18(+) cells . This pathology is strongly dependent on protein translocation via the serovar Typhimurium SPI1 type III secretion system . Using a lymphotoxin beta-receptor knockout mouse strain that lacks all lymph nodes and organized gut-associated lymphatic tissues, we demonstrate that Peyer's patches and mesenteric lymph nodes are dispensable for the initiation of murine serovar Typhimurium colitis . Our results demonstrate that streptomycin-pretreated mice offer a unique infection model that allows for the first time to use mutants of both the pathogen and the host to study the molecular mechanisms of enteric salmonellosis. J Biol Chem, 2003 Jun 27, 278(26), 23579 - 85 Epub 2003 Apr 17. The H box-harboring domain is key to the function of the Salmonella enterica PhoQ Mg2+-sensor in the recognition of its partner PhoP; Castelli ME et al.; In two-component signaling systems, the transduction strategy relies on a conserved His-Asp phosphoryl exchange between the sensor histidine kinase and its cognate response-regulator, and structural and functional consensus motifs are found when comparing either the diverse histidine kinases or response regulators present in a single cell . Therefore, the mechanism that guarantees the specific recognition between partners of an individual pair is essential to unequivocally generate the appropriate adaptive response . Based on sequence alignments with other histidine kinases, we dissected the Salmonella enterica Mg2+-sensor PhoQ in different subdomains and examined by in vivo and in vitro assays its interaction with the associated response regulator PhoP . This signal transduction system allows Salmonella to withstand environmental Mg2+ limitation by triggering gene expression that is vital throughout the infective cycle in the host . Using resonant mirror biosensor technology, we calculated the kinetic and equilibrium binding constants and determined that the His-phosphotransfer domain is essential for the PhoQ specific recognition and interaction with PhoP . Additionally, we show the role of this domain in the bimolecular transphosphorylation and provide evidence that this region undergoes dimerization. Emerg Infect Dis, 2003 Apr, 9(4), 496 - 9 Automated ribotyping and pulsed-field gel electrophoresis for rapid identification of multidrug-resistant Salmonella serotype newport; Fontana J et al.; In a series of 116 Salmonella enterica Newport isolates that included 64 multidrug-resistant (MDR) isolates, automated ribotyping and pulsed-field gel electrophoresis (PFGE) discriminated MDR S . Newport with a sensitivity of 100% and 98% and specificity of 76% and 89%, respectively . Clustering of PFGE patterns (but not ribotyping) linked human and bovine cases . Automated ribotyping rapidly identified the MDR strain, and PFGE detected associations that aided epidemiologic investigations. Emerg Infect Dis, 2003 Apr, 9(4), 493 - 5 First incursion of Salmonella enterica serotype typhimurium DT160 into New Zealand; Thornley CN et al.; An outbreak of human Salmonella enterica serotype Typhimurium DT160 infection in New Zealand was investigated from May to August 2001 . Handling of dead wild birds, contact with persons with diarrheal illness, and consumption of fast food were associated with infection . Contaminated roof-collected rainwater was also detected. Emerg Infect Dis, 2003 Apr, 9(4), 474 - 9 Alfalfa seed decontamination in a Salmonella outbreak; Gill CJ et al.; Based on in vitro data, the U.S . Food and Drug Administration recommends chemical disinfection of raw sprout seeds to reduce enteric pathogens contaminating the seed coats . However, little is known about the effectiveness of decontamination at preventing human disease . In 1999, an outbreak of Salmonella enterica serotype Mbandaka occurred in Oregon, Washington, Idaho, and California . Based on epidemiologic and pulsed-field gel electrophoresis evidence from 87 confirmed cases, the outbreak was linked to contaminated alfalfa seeds grown in California's Imperial Valley . Trace-back and trace-forward investigations identified a single lot of seeds used by five sprout growers during the outbreak period . Cases of salmonellosis were linked with two sprout growers who had not employed chemical disinfection; no cases were linked to three sprout growers who used disinfection . This natural experiment provides empiric evidence that chemical disinfection can reduce the human risk for disease posed by contaminated seed sprouts. J Bacteriol, 2003 May, 185(9), 2936 - 43 Species-wide variation in the Escherichia coli flagellin (H-antigen) gene; Wang L et al.; Escherichia coli is a clonal species . The best-understood components of its clonal variation are the flagellar (H) and polysaccharide (O) antigens, both well documented since the mid-1930s because of their use in serotyping . Flagellin is the protein subunit of the flagellum that carries H-antigen specificity . We show that 43 of the 54 H-antigen specificities of E . coli map to the flagellin gene at fliC and sequenced all 43 forms and confirmed specificity of each by cloning and expression . This is, to our knowledge, the first time that all known forms of such a highly polymorphic gene have been fully sequenced and characterized for any species . The established distinction between a highly variable central region and more conserved flanking regions is upheld . The sequences fall into two groups, one of which may be derived from the fliC gene of the E . coli/Salmonella enterica common ancestor, the other perhaps obtained by lateral transfer since species divergence . Comparison of sequences revealed that both horizontal DNA transfer and fixation of mutations under diversifying selection pressure contributed to polymorphism in this locus. J Bacteriol, 2003 May, 185(9), 2802 - 10 Propionyl coenzyme A is a common intermediate in the 1,2-propanediol and propionate catabolic pathways needed for expression of the prpBCDE operon during growth of Salmonella enterica on 1,2-propanediol; Palacios S et al.; The studies reported here identify propionyl coenzyme A (propionyl-CoA) as the common intermediate in the 1,2-propanediol and propionate catabolic pathways of Salmonella enterica serovar Typhimurium LT2 . Growth on 1,2-propanediol as a carbon and energy source led to the formation and excretion of propionate, whose activation to propionyl-CoA relied on the activities of the propionate kinase (PduW)/phosphotransacetylase (Pta) enzyme system and the CobB sirtuin-controlled acetyl-CoA and propionyl-CoA (Acs, PrpE) synthetases . The different affinities of these systems for propionate ensure sufficient synthesis of propionyl-CoA to support wild-type growth of S . enterica under low or high concentrations of propionate in the environment . These redundant systems of propionyl-CoA synthesis are needed because the prpE gene encoding the propionyl-CoA synthetase enzyme is part of the prpBCDE operon under the control of the PrpR regulatory protein, which needs 2-methylcitrate as a coactivator . Because the synthesis of 2-methylcitrate by PrpC (i.e., the 2-methylcitrate synthase enzyme) requires propionyl-CoA as a substrate, the level of propionyl-CoA needs to be raised by the Acs or PduW-Pta system before 2-methylcitrate can be synthesized and prpBCDE transcription can be activated. BMC Bioinformatics . 2003 Apr 03;4(1):12. Significance analysis of lexical bias in microarray data; Kim CC et al.; BACKGROUND: Genes that are determined to be significantly differentially regulated in microarray analyses often appear to have functional commonalities, such as being components of the same biochemical pathway . This results in certain words being under- or overrepresented in the list of genes . Distinguishing between biologically meaningful trends and artifacts of annotation and analysis procedures is of the utmost importance, as only true biological trends are of interest for further experimentation . A number of sophisticated methods for identification of significant lexical trends are currently available, but these methods are generally too cumbersome for practical use by most microarray users . RESULTS: We have developed a tool, LACK, for calculating the statistical significance of apparent lexical bias in microarray datasets . The frequency of a user-specified list of search terms in a list of genes which are differentially regulated is assessed for statistical significance by comparison to randomly generated datasets . The simplicity of the input files and user interface targets the average microarray user who wishes to have a statistical measure of apparent lexical trends in analyzed datasets without the need for bioinformatics skills . The software is available as Perl source or a Windows executable . CONCLUSION: We have used LACK in our laboratory to generate biological hypotheses based on our microarray data . We demonstrate the program's utility using an example in which we confirm significant upregulation of SPI-2 pathogenicity island of Salmonella enterica serovar Typhimurium by the cation chelator dipyridylPublication Types:
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