J Bacteriol, 2002 Jun, 184(12), 3151 - 8 Regulation of Salmonella enterica serovar Typhimurium mntH transcription by H(2)O(2), Fe(2+), and Mn(2+); Kehres DG et al.; MntH, a bacterial homolog of mammalian natural resistance associated macrophage protein 1 (Nramp1), is a primary transporter for Mn(2+) influx in Salmonella enterica serovar Typhimurium and Escherichia coli . S . enterica serovar Typhimurium MntH contributes to H(2)O(2) resistance and is important for full virulence . Consistent with its phenotype and function, mntH is regulated at the transcriptional level by both H(2)O(2) and substrate cation . We have now identified three trans-acting regulatory factors and the three corresponding cis-acting mntH promoter motifs that mediate this regulation . In the presence of hydrogen peroxide, mntH is activated by OxyR, acting through an OxyR-binding motif centered just upstream of the likely -35 RNA polymerase-binding site . In the presence of Fe(2+), mntH is repressed primarily by Fur, acting through a Fur-binding motif overlapping the -35 region . In the presence of Mn(2+), mntH is repressed primarily by the Salmonella equivalent of E . coli b0817, a distant homolog of the Bacillus subtilis manganese transport repressor, MntR, acting through an inverted-repeat motif located between the likely -10 polymerase binding site and the ribosome binding site . E . coli b0817 was recently shown to bind the identical inverted-repeat motif in the E . coli mntH promoter and hence has been renamed MntR (S . I . Patzer and K . Hantke, J . Bacteriol . 183:4806-4813, 2001) . Using Deltafur, DeltamntR, and Deltafur DeltamntR mutant strains as well as mutations in the Fur- and MntR-binding motif elements, we found that Fe(2+) can also mediate repression through the Mn(2+) repressor MntR. Res Vet Sci, 2002 Apr, 72(2), 87 - 93 The multiple antibiotic resistance (mar) locus and its significance; Randall LP et al.; Chromosomally encoded systems involved in low level resistance of bacteria to different classes of antibiotics (mainly beta-lactams, chloramphenicol, quinolones and tetracycline), disinfectants and in resistance to organic solvents have been the focus of considerable interest in recent years . The multiple antibiotic resistance (mar) locus of Escherichia coli and Salmonella is perhaps the best described system involved in this type of resistance which is induced by MarA, the activator protein encoded by the marRAB locus . The mar -locus is reported to mediate resistance primarily by up-regulating efflux of some antibiotics, disinfectants and organic solvents via the AcrAB-TolC efflux pump and down regulating influx through Outer Membrane Protein F (OmpF) . Whilst the level of antibiotic resistance conferred by marRAB is only low level, there are increasing data to suggest that marRAB and related systems are important in clinical antibiotic resistance, possibly as a 'stepping stone' to higher levels of resistance . Other related systems include up-regulation of RobA, SoxS and AcrAB which give rise to a similar resistance phenotype to that conferred by up-regulation of MarA . The aim of this paper is to review the function and significance of the mar -locus and related systems with a particular focus on its implications in veterinary medicine . FEMS Microbiol Lett, 2002 Apr 23, 210(1), 99 - 103 The sctR of Salmonella enterica serova Typhimurium encoding a homologue of MerR protein is involved in the copper-responsive regulation of cuiD; Kim JS et al.; We have identified the cuiD gene in Salmonella enterica serova Typhimurium that codes for a putative multicopper oxidase . Expression of cuiD is induced by copper ion and its promoter/operator has sequence similarity to the promoters controlled by the transcriptional regulators of the MerR family . We also identified and isolated a gene from S . enterica serova Typhimurium that encodes a 138-amino acid residue protein, sctR, a new member of the MerR family of transcriptional regulators . Transposon-insertional disruption of sctR shows sensitivity to copper ion and no response of cuiD expression . Copper-responsive induction and copper tolerance were restored by providing sctR in trans, suggesting that SctR plays an important role in intracellular copper detoxification. Risk Anal, 2002 Apr, 22(2), 203 - 18 An overview of the Salmonella enteritidis risk assessment for shell eggs and egg products; Hope BK et al.; This article summarizes a quantitative microbial risk assessment designed to characterize the public health impact of consumption of shell eggs and egg products contaminated with Salmonella Enteritidis (SE) . This risk assessment's objectives were to: (1) establish the baseline risk of foodborne illness from SE, (2) identify and evaluate potential risk mitigation strategies, and (3) identify data gaps related to future research efforts . The risk assessment model has five modules . The Egg Production module estimates the number of eggs produced that are SE-contaminated . Shell Egg Processing, Egg Products Processing, and Preparation & Consumption modules estimate the increase or decrease in the numbers of SE organisms in eggs or egg products as they pass through storage, transportation, processing, and preparation . A Public Health Outcomes module then calculates the incidence of illnesses and four clinical outcomes, as well as the cases of reactive arthritis associated with SE infection following consumption . The baseline model estimates an average production of 2.3 million SE-contaminated shell eggs/year of the estimated 69 billion produced annually and predicts an average of 661,633, human illnesses per year from consumption of these eggs . The model estimates approximately 94% of these cases recover without medical care, 5% visit a physician, an additional 0.5% are hospitalized, and 0.05% result in death . The contribution of SE from commercially pasteurized egg products was estimated to be negligible . Five mitigation scenarios were selected for comparison of their individual and combined effects on the number of human illnesses . Results suggest that mitigation in only one segment of the farm-to-table continuum will be less effective than several applied in different segments . Key data gaps and areas for future research include the epidemiology of SE on farms, the bacteriology of SE in eggs, human behavior in food handling and preparation, and human responses to SE exposure. J Trop Pediatr, 2002 Apr, 48(2), 102 - 8 Complications of bacteriologically confirmed typhoid fever in children; Malik AS; To find the incidence, markers and nature of complications of typhoid fever, we studied 102 children with cultures positive for Salmonella typhi in a cross-sectional study, prospectively, over a period of almost 5 years . All isolates were sensitive to commonly used antibiotics . One third of these children developed complications which included: anicteric hepatitis, bone marrow suppression, paralytic ileus, myocarditis, psychosis, cholecystitis, osteomyelitis, peritonitis, pneumonia, haemolysis, and syndrome of inappropriate release of antidiuretic hormone (SIADH) . Twelve children developed multiple complications . If hepatitis is excluded from the complications, the rate of complications in bacteriologically confirmed cases of typhoid fever drops to 11 per cent . These complications were not related to: the age or sex of patients, duration of illness before admission, use of antibiotics before admission, nutritional status, level of 'O' or 'H' titre, presence of IgM or IgG antibodies, or treatment with chloramphenicol or ampicillin . Children with splenomegaly, thrombocytopenia or leukopenia were more likely to develop complications. Antimicrob Agents Chemother, 2002 Jun, 46(6), 1971 - 3 Reducing mortality in Salmonella enterica serovar Typhimurium-infected mice with a tripeptidic serum fraction; Parker TA et al.; Salmonellosis-induced mortality in female Swiss Webster mice decreased significantly when tripeptidic immunostimulant (TPI) was administered prophylactically . Prophylactic benefits developed in a dose-dependent manner wherein 15 mg of TPI given 1 day before challenge reduced mortality by 70%. Antimicrob Agents Chemother, 2002 Jun, 46(6), 1714 - 22 Characterization of variant Salmonella genomic island 1 multidrug resistance regions from serovars Typhimurium DT104 and Agona; Boyd D et al.; Strains of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (DT104) and S . enterica serovar Agona (Agona) have been found to harbor Salmonella genomic island 1 (SGI1), a 43-kb genomic region that contains many of the drug resistance genes . Such strains are resistant to ampicillin (pse-1), chloramphenicol/florfenicol (floR), streptomycin/spectinomycin (aadA2), sulfonamides (sul1), and tetracycline {tet(G)} (commonly called the ACSSuT phenotype) . All five resistance genes are found in a 13-kb multidrug resistance (MDR) region consisting of an unusual class I integron structure related to In4 . We examined DT104 and Agona strains that exhibited other resistance phenotypes to determine if the resistance genes were associated with variant SGI1 MDR regions . All strains were found to harbor variant SGI1-like elements by using a combination of Southern hybridization, PCR mapping, and sequencing . Variant SGI1-like elements were found with MDR regions consisting of (i) an integron consisting of the SGI1 MDR region with the addition of a region containing a putative transposase gene (orf513) and dfrA10 located between duplicated qacEDelta1/sulI genes (SGI1-A; ACSSuTTm); (ii) an integron with either an aadA2 (SSu) or a pse-1 (ASu) cassette (SGI1-C and SGI1-B, respectively); (iii) an integron consisting of the SGI1-C MDR region plus an orf513/dfrA10 region as in SGI1-A (SGI1-D; ASSuTm; ampicillin resistance due to a TEM beta-lactamase); and (iv) an integron related to that in SGI1 but which contains a 10-kb inversion between two copies of IS6100, one which is inserted in floR (SGI1-E; ASSuT) . We hypothesize that the MDR of SGI1 is subject to recombinational events that lead to the various resistance phenotypes in the Salmonella strains in which it is found. Mol Cells, 2002 Apr 30, 13(2), 281 - 7 Fingerprinting of diverse genomes using PCR with universal rice primers generated from repetitive sequence of Korean weedy rice; Kang HW et al.; Twenty primers of 20 mer referred to universal rice primer (URP) were developed from a repetitive sequence of rice genome . URP-PCR protocol employed stringent PCR with high annealing temperature throughout the thermo-cycling reaction, giving high reproducibility . Under the PCR condition, each single URP primer produced characteristic fingerprints from diverse genomes containing 14 plants, 7 animals and 6 microbes, indicating its universal applicability . The generality of URP-PCR was demonstrated by applying it to 15 cultivars from five rice species, 23 isolates in four Alternaria species producing host-specific toxins on different host plants and 12 bacterial strains including Escherichia coli, Salmonella spp., and Blucella abortus . PCR approach using URP primers will be useful for studying DNA diversity of most eukaryotic or prokaryotic genomes, especially at inter- and intraspecies levels. Am J Med Sci, 2002 May, 323(5), 266 - 8 Salmonella meningitis in adults infected with HIV: case report and review of the literature; Leonard MK et al.; We report a case of Salmonella infantis meningitis in a patient infected with HIV who was successfully treated with 4 weeks of therapy and has had no relapses after 12 months of follow-up . Only 10 episodes of Salmonella species meningitis in patients infected with HIV are reported in the literature. J Med Microbiol, 2002 Jun, 51(6), 503 - 9 Factors affecting haemolysin production and congo red binding in Salmonella enterica serovar Typhimurium DT 98; Tiwari RP et al.; Differences in haemolysin expression were observed in a strain of Salmonella enterica serovar Typhimurium definitive phage type (DT) 98 cultured under various conditions . Haemolysin expression was optimal in cultures grown micro-aerobically . The zones of haemolysis were wider after longer periods of incubation . Haemolysin production varied after growth in the following media (greatest to least): brain heart infusion (BHI) broth > nutrient broth (NB)>trypticase soy broth (TSB)> M-9 glucose medium . Haemolysin production correlated directly with Congo red binding in nutrient broth . On Congo red blood agar, colonies were smaller, with dark centres and wider zones of haemolysis . Culture-cell-free haemolysin activity was higher, but cell-bound haemolysin activity was very low in growth medium supplemented with Congo red . Boiled tea extract at 25% v/v (of 25% w/v tea infusion) in PBS and nutrient broth was bactericidal to S . Typhimurium DT 98 . The addition of boiled tea extract to growth medium inhibited haemolysin production by S . Typhimurium DT 98 at higher concentrations (6-12.5% v/v) but stimulated haemolysin production at lower concentrations (1.5-3% v/v) . The pre-treatment of bacterial cell suspensions with lower concentrations of tea extract (1.5-3% v/v) also altered the Congo red binding, which showed an inverse correlation in nutrient broth. Infection, 2002 Apr, 30(2), 104 - 8 Salmonella meningitis: report of three cases in adults and literature review; Karim M et al.; Salmonella meningitis is an unusual complication of Salmonella sepsis and occurs almost exclusively in infants and young children . One case of Salmonella meningitis and two cases of cerebrospinal fluid (CSF) pleocytosis in adult patients with Salmonella bacteremia were studied and the literature was reviewed . On a retrospective review of the charts of 100 sequential patients with Salmonella typhi and S . paratyphi-positive blood cultures, we found one patient with fulminant Salmonella meningitis and two others with CSF pleocytosis . All three patients survived . The patient with Salmonella meningitis had significant residual neurologic sequela . Salmonella encephalopathy occurred in six other patients who presented with headache and were confused or drowsy . Cases of meningitis in adults do occur and are associated with a high morbidity and mortality . Newer cephalosporn antibiotics may be the therapy of choice in these infections. Eur J Cell Biol, 2002 Apr, 81(4), 203 - 12 Establishment and characterization of partially differentiated chicken enterocyte cell clones; Velge P et al.; Three enterocyte cell clones were established in vitro from the intestine of a PA12 hen embryo . These cells exhibited epithelioid morphology and grew as monolayers . The cells were continuously propagated in culture up to 250 passages . Gradual increase in growth rate with time and in anchorage-independent growth in both agar and agarose showed that the three cell clones spontaneously transformed in vitro . The clones were heteroploid with one marker chromosome . Interestingly, they had features of partly differentiated enterocytes, especially microvilli, junctions connecting adjacent cells (tight junctions, desmosomes, hemidesmosomes, gap junctions), villin and cytokeratins . In addition, cells expressed brush border enzyme activity and transepithelial resistance . The fact that the levels of dipeptidyl peptidase IV (DPP-IV) and alkaline phosphatase activities fluctuated according to culture time and that MHC class II was induced by activation of cells with interferon suggested that the state of differentiation of the 3 cell clones could be modified in vitro . These clones are the first established avian enterocyte cell clones to be described . Because each cell clone exhibited differences in the level of differentiation and sensitivity to Salmonella infection, their use will allow comparative investigations concerning markers of differentiation of avian enterocytes and infection by host-adapted bacteria and parasites. Risk Anal, 2002 Feb, 22(1), 47 - 58 A probabilistic transmission model of Salmonella in the primary broiler production chain; Ranta J et al.; Annual data from the Finnish National Salmonella Control Programme were used to build up a probabilistic transmission model of salmonella in the primary broiler production chain . The data set consisted of information on grandparent, parent, and broiler flock populations . A probabilistic model was developed to describe the unknown true prevalences, vertical and horizontal transmissions, as well as the dynamical model of infections . By combining these with the observed data, the posterior probability distributions of the unknown parameters and variables could be derived . Predictive distributions were derived for the true number of infected broiler flocks under the adopted intervention scheme and these were compared with the predictions under no intervention . With the model, the effect of the intervention used in the programme, i.e., eliminating salmonella positive breeding flocks, could be quantitatively assessed . The 95% probability interval of the posterior predictive distribution for (broiler) flock prevalence under current (1999) situation was {1.3%-17.4%} (no intervention), and {0.9%-5.8%} (with intervention) . In the scenario of one infected grandparent flock, these were {2.8%-43.1%} and {1.0%-5.9%}, respectively . Computations were performed using WinBUGS and Matlab softwares. J Vet Med B Infect Dis Vet Public Health, 2002 Apr, 49(3), 160 - 2 Bacterial resistance to quinolone antibiotics in Poland; Rolinski Z et al.; The resistance of 167 pathogenic bacteria of animal origin to quinolones was determined by the disc diffusion method, and by the minimum inhibitory concentration (MIC) test . The highest resistance of Escherichia coli was found to be against nalidixic acid (NA), 49.1% and flumequine (FLU), 38.2% . The sensitivity of the strains were: ciprofloxacin (CIP; 81.8%); enrofloxacin (ENR; 81.8%); norfloxacin (NOR; 80.0%); and pefloxacin (PE; 76.4%) . Salmonella spp . showed 100% sensitivity to CIP, ENR, NOR and PE . A high resistance percentage in the cases of: FLU (86.7%); PE (50.0%); and CIP (26.65%) distinguished the Streptococcus spp . The highest percentage sensitivity of Staphylococci was found with three fluoroquinolones: CIP, ENR and NOR, 94.3% each (66 strains) . The studies did not indicate that a total cross-resistance might occur between the examined quinolones. Zhonghua Liu Xing Bing Xue Za Zhi, 2002 Feb, 23(1), 50 - 3 {Diversity of 16s rDNA ribotypes of the Salmonella typhi strains isolated in Guizhou province}; Tian K et al.; OBJECTIVE: To analyses the genetic diversity and relationship of Salmonella typhi strains isolated from different years and districts in Guizhou province . METHODS: Ribotyping with 16s rDNA probe was used to describe the diversity of the 209 strains which were isolated in 26 counties of Guizhou province, from 1959 to 1999 . The antibiotics resistance was also studied . RESULTS: Twenty-six ribotypes were found in all 209 strains, with two dominant types . The strains isolated from local typhoid epidemics belonged to the unique Ribotypes . The major ribotypes of the resistant strains were RT7 and RT1 . CONCLUSION: The Salmonella typhi isolates from Guizhou diverged obviously . The abundant clones and multi-resistance of the strains might serve the major reasons of the high morbidity of typhoid in Guizhou. Zhonghua Zhong Liu Za Zhi, 2002 Mar, 24(2), 137 - 40 {Anti-mutagenicity activity of dehydroepiandrosterone}; Yang S et al.; OBJECTIVE: The chemopreventive activity and mechanism of dehydroepiandrosterone (DHEA) were studied . METHODS: Model of 7, 12-dimethylbenz (alpha) anthracene (DMBA) induced breast carcinoma in Sprague-Dawley rats, uitra-violet (UV)-induced DNA damage and Salmonella mutation assay were used . RESULTS: In DMBA-induced rat mammary tumor model, the rats were orally given daily DHEA for 2 weeks before DMBA and continued for 10 weeks after DMBA administration . The results showed significant inhibition of tumor development by DHEA . The incidence of mammary carcinoma also decreased significantly on daily dose of oral 25 mg/kg DHEA with the mean tumor volume per rat also remarkably reduced by 92% . Moreover, 25 mg/kg DHEA treatment could significantly increase the carcinoma latency for about 3.5 weeks as compared with the control . Using polymerase chain reaction (PCR) assay, in vitro 10(-9) mol/L DHEA showed significant inhibitory effect on UV-induced DNA damage by 90% . In Ames test, DHEA was found to decrease DMBA and benzo (alpha) pyrene-induced TA98 and TA100 His(+) revertants markedly and the number of Salmonella clones were significantly reduced by 53.2% and 73.0% on dose of 5 microgram DHEA/plate . It was also shown that in vitro 10(-7) mol/L DHEA could also effectively inhibit the G-6-PDH activity, which might play an important role in its chemoprophylaxis activities . CONCLUSION: The results strongly prove that DHEA is a potent cancer chemoprophylaxis agent, which exhibits inhibitory potential on mutation and chemical carcinogen in vivo and in vitro. Shi Yan Sheng Wu Xue Bao, 1998 Mar, 31(1), 49 - 60 A potential approach to antifertility vaccine by expression of sperm membrane peptide in Salmonella; Gao AW et al.; A synthetic oligonucleotide, HSD-2a, encoding a peptide segment of the extracellular domain of a human sperm membrane protein, YWK-II, was inserted by blunt-end ligation at the EcoRV site in the hypervariable, antigenically determinant region IV of Salmonella flagellin gene fliC (d) . The recombinant plasmid (pLS408-H1) was transferred into the nonpathogenic aroA live vaccine Salmonella dublin strain SL5928, which is flagellin-negative . Location of the HSD-2a protein on the surface of the flagella was demonstrated by ELISA and by immunogold-labeling electron microscopy using mouse anti-YWK-II antiserum . A 60 kD protein, corresponding to the chimeric flagellin, was isolated from the recombinant S . dublin and found to contain the expressed HSD-2a peptide determined by Western blot analysis using anti-YWK-II antiserum . The Salmonella strain carrying the recombinant plasmid-pLS408-H1 may thus be a potential source of antifertility vaccine. Rev Epidemiol Sante Publique, 2002 Apr, 50(2), 219 - 32 {The capture-recapture applied to epidemiology: principles, limits and application}; Gallay A et al.; By matching several sources of information coming from the same population, the capture-recapture method allows, if matches between sources can be identified, to estimate the number of cases not identified by any of the sources, the total number (N) of cases in the population and the sensitivity of each source . Used first in zoology and demography, this technique has been increasingly applied to epidemiology in the last two decades . However, six conditions need to be satisfied: all cases identified by each source are true cases; occurred during the time and the geographical area studied; the study population is closed; all matches are true matches; sources are independent and there is no heterogeneous catchability within sources . It is possible to assess and take into account dependence between sources when 3 or more sources are used, in particular by log linear modelling . However interactions of maximal order cannot be adjusted for . In case of a biased estimation because of the non respect of the conditions, it is recommended to apply a method of correction . The complete application of the methods is illustrated in the study of estimating the number of Salmonella infectious foodborne outbreak . As capture-recapture studies often use data collected for other purposes, this technique should be regarded as exploratory or be used to validate an estimate of a number of cases obtained by another method . It should not replace population sampling methods only because of its low cost . Otherwise it is a very informative approach to evaluate the sensitivity and representativeness of surveillance systems and registries. J Biol Chem, 2002 Jul 26, 277(30), 26893 - 903 Epub 2002 May 13. Molecular basis defining human Chlamydia trachomatis tissue tropism . A possible role for tryptophan synthase; Fehlner-Gardiner C et al.; Here we report the cloning and sequencing of a region of the chlamydiae chromosome termed the "plasticity zone" from all the human serovars of C . trachomatis containing the tryptophan biosynthesis genes . Our results show that this region contains orthologues of the tryptophan repressor as well as the alpha and beta subunits of tryptophan synthase . Results from reverse transcription-PCR and Western blot analyses indicate that the trpBA genes are transcribed, and protein products are expressed . The TrpB sequences from all serovars are highly conserved . In comparison with other tryptophan synthase beta subunits, the chlamydial TrpB subunit retains all conserved amino acid residues required for beta reaction activity . In contrast, the chlamydial TrpA sequences display numerous mutations, which distinguish them from TrpA sequences of all other prokaryotes . All ocular serovars contain a deletion mutation resulting in a truncated TrpA protein, which lacks alpha reaction activity . The TrpA protein from the genital serovars retains conserved amino acids required for catalysis but has mutated several active site residues involved in substrate binding . Complementation analysis in Escherichia coli strains, with defined mutations in tryptophan biosynthesis, and in vitro enzyme activity data, with cloned TrpB and TrpA proteins, indicate these mutations result in a TrpA protein that is unable to utilize indole glycerol 3-phosphate as substrate . In contrast, the chlamydial TrpB protein can carry out the beta reaction, which catalyzes the formation of tryptophan from indole and serine . The activity of the chlamydial Trp B protein differs from that of the well characterized E . coli and Salmonella TrpBs in displaying an absolute requirement for full-length TrpA . Taken together our data indicate that genital, but not ocular, serovars are capable of utilizing exogenous indole for the biosynthesis of tryptophan. Infect Immun, 2002 Jun, 70(6), 3290 - 4 Characterization of the spv locus in Salmonella enterica serovar Arizona; Libby SJ et al.; Salmonella enterica serovar Arizona (S . enterica subspecies IIIa) is a common Salmonella isolate from reptiles and can cause serious systemic disease in humans . The spv virulence locus, found on large plasmids in Salmonella subspecies I serovars associated with severe infections, was confirmed to be located on the chromosome of serovar Arizona . Sequence analysis revealed that the serovar Arizona spv locus contains homologues of spvRABC but lacks the spvD gene and contains a frameshift in spvA, resulting in a different C terminus . The SpvR protein functions as a transcriptional activator for the spvA promoter, and SpvB and SpvC are highly conserved . The analysis supports the proposal that the chromosomal spv sequence more closely corresponds to the ancestral locus acquired during evolution of S . enterica, with plasmid acquisition of spv genes in the subspecies I strains involving addition of spvD and polymorphisms in spvA. Infect Immun, 2002 Jun, 70(6), 3264 - 70 Disruption of the Salmonella-containing vacuole leads to increased replication of Salmonella enterica serovar typhimurium in the cytosol of epithelial cells; Brumell JH et al.; Salmonella enterica serovar Typhimurium is a facultative intracellular pathogen that inhabits a vacuolar compartment, called the Salmonella-containing vacuole (SCV), in infected host cells . Maintenance of the SCV is accomplished by SifA, and mutants of this Salmonella pathogenicity island 2 type III effector replicate more efficiently in epithelial cells . Here we demonstrate that enhanced replication of sifA mutants occurs in the cytosol of these cells . Increased replication of wild-type bacteria was also observed in cells treated with wortmannin or expressing Rab5 Q79L or Rab7 N125I, all of which caused a loss of SCV integrity . Our findings demonstrate the requirement of the host cell endosomal system for maintenance of the SCV and that loss of this compartment allows increased replication of serovar Typhimurium in the cytosol of epithelial cells. Infect Immun, 2002 Jun, 70(6), 3130 - 42 Role of nitric oxide in host defense in murine salmonellosis as a function of its antibacterial and antiapoptotic activities; Alam MS et al.; Host defense functions of nitric oxide (NO) are known for many bacterial infections . In this study, we investigated the antimicrobial effect of NO in murine salmonellosis by using inducible NO synthase (iNOS)-deficient mice infected with an avirulent or virulent Salmonella enterica serovar Typhimurium strain . All iNOS-deficient mice died of severe septicemia within 6 days after intraperitoneal injection with an avirulent strain (LT2) to which wild-type mice were highly resistant; 50% lethal doses (LD(50)s) of the LT2 strain for iNOS-deficient and wild-type mice were 30 CFU and 7 x 10(4) CFU, respectively . Lack of NO production in iNOS-deficient mice was verified directly by electron spin resonance spectroscopy . Bacterial yields in liver and blood were much higher in iNOS-deficient mice than in wild-type mice throughout the course of infection . Very small amounts of a virulent strain of serovar Typhimurium (a clinical isolate, strain Gifu 12142; LD(50), 50 CFU) given orally caused severe septicemia in iNOS-deficient animals; wild-type mice tolerated higher doses (LD(50), 6 x 10(2) CFU) . Histopathology of livers from infected iNOS-deficient mice revealed extensive damage, such as diffuse hepatocellular apoptosis and increased neutrophil infiltration, but livers from infected wild-type mice showed a limited number of microabscesses, consisting of polymorphonuclear cells and macrophages and low levels of apoptotic change . The LT2 strain was much more susceptible to the bactericidal effect of peroxynitrite than the Gifu strain, suggesting that peroxynitrite resistance may contribute to Salmonella pathogenicity . These results indicate that NO has significant host defense functions in Salmonella infections not only because of its direct antimicrobial effect but also via cytoprotective actions for infected host cells, possibly through its antiapoptotic effect. J Appl Microbiol, 2002, 92(6), 1167 - 71 Genetic diversity of Salmonella enterica serovar Paratyphi A from different geographical regions in Asia; Goh YL et al.; AIMS: Subtyping of Salmonella Paratyphi A isolates from India, Pakistan, Indonesia and Malaysia was carried out by pulsed-field gel electrophoresis (PFGE) to assess the extent of genetic diversity of these isolates from different endemic countries . METHODS AND RESULTS: A total of 39 human isolates of Salmonella Paratyphi A from Pakistan, India, Indonesia and Malaysia were studied using PFGE analysis following digestion of chromosomal DNA with XbaI . Seven isolates from Pakistan were resistant to ampicillin, tetracycline and cotrimoxazole . It was noted that Salmonella Paratyphi A isolates obtained from outbreaks in India had limited genetic diversity and probably belonged to closely related clones . Significant genetic homogeneity was observed among antimicrobial-resistant isolates from Pakistan and antimicrobial-sensitive isolates from Pakistan and Indonesia, respectively . CONCLUSIONS: PFGE was a useful subtyping technique to differentiate Salmonella Paratyphi A from different endemic countries . However, it fails to differentiate the antimicrobial-resistant and -sensitive strains . SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of the present study verify the usefulness of PFGE in characterizing and comparing strains of Salmonella Paratyphi A . Our study suggests that a limited number of clones are responsible for paratyphoid fever in these countries. Mol Microbiol, 2002 May, 44(4), 1017 - 32 The effect of genomic position on reversion of a lac frameshift mutation (lacIZ33) during non-lethal selection (adaptive mutation); Slechta ES et al.; In a system described by Cairns and Foster, starvation of a particular leaky lac mutant (lacIZ33) in the presence of lactose appears to direct mutation in non-growing cells to sites that allow growth (adaptive mutation) . This behaviour requires that the lac operon be located on an F' plasmid . This position effect was investigated by placing the mutant lac operon at many sites in the genome of Salmonella enterica (Typhimurium; LT2) and testing reversion behaviour . Genomic position did not affect reversion during non-selective growth . When lac was at any of 550 chromosomal sites, starvation caused little or no enhancement of reversion . In the 28 strains with the lac on Salmonella's conjugative plasmid (pSLT), selection enhanced reversion strongly, just as seen for strains with lac on an F' plasmid . In 46 strains, the lac operon was inserted within a small chromosomal duplication, and selection stimulated RecA-dependent partial reversion by simple amplification (about 8x) of the mutant lac region . The position of lac on a conjugative plasmid is important to reversion because it allows more frequent gene duplication and amplification . These events are central to growth and reversion under selection because they increase the number of replicating lac alleles within each developing revertant clone. Clin Microbiol Infect, 2002 Mar, 8(3), 154 - 61 Combination of pulsed-field gel electrophoresis (PFGE) and single-enzyme amplified fragment length polymorphism (SAFLP) for differentiation of multiresistant Salmonella enterica serotype typhimurium; Sood S et al.; OBJECTIVE: To assess the combined application of plasmid profile typing, pulsed-field gel electrophoresis (PFGE) and PCR-based single-enzyme amplified fragment length polymorphism (SAFLP) for the differentiation of 18 multiresistant (MR) and one drug-sensitive strain of Salmonella enterica serotype typhimurium from humans and food animals . METHODS: Strains were phage typed and tested for resistance to a panel of antimicrobial agents . Strains were also tested for the ability to transfer resistance either directly or by mobilization to standard strains of Escherichia coli K12 . Plasmid DNA was extracted from both drug-resistant donor strains and from drug-resistant exconjugants . Total genomic DNA was characterized by PFGE following digestion with the restriction endonuclease XbaI . The resultant patterns were categorized and analyzed by dendrogram analysis using the Dice coefficient and by data clustering using unweighted pair-group arithmetic averaging (UPGMA) . Isolates were also characterized and categorized by SAFLP . The levels of discrimination achieved by each method were assessed individually and in combination . RESULTS: Plasmid DNA was detected in all of the 18 MR isolates but, not in the drug-sensitive isolate . Using PFGE, 19 different profiles were identified, falling into eight major categories . However, by SAFLP, only eight profiles were observed . Subsequent investigations have demonstrated epidemiologic relationships within at least one of these SAFLP profile groupings . CONCLUSIONS: These studies have demonstrated that PFGE and SAFLP can be used independently for the differentiation of MR S . Typhimurium from humans and food animals . However, when used in combination, SAFLP can provide a format for broad epidemiologic groupings . These groupings can be further subdivided by PFGE to provide detailed information on putative strain relationships at the genotypic level. Mol Immunol, 2002 May, 38(12-13), 931 - 40 Cytokine expression by attenuated intracellular bacteria regulates the immune response to infection: the Salmonella model; al-Ramadi BK et al.; Attenuated Salmonella strains have shown excellent efficacy as mucosal vaccine delivery systems . In the present report, several recombinant strains of Salmonella enterica serovar Typhimurium, engineered to express defined murine cytokines, were used to study their potential immunoregulatory capacity in the mouse model of typhoid fever . Specifically, recombinant strains expressing IL-2 (known as GIDIL2) or TNF-alpha (GIDTNF) were compared with the parental, non-cytokine-secreting, strain (BRD509) for their ability to induce a variety of immune responses in susceptible BALB/c mice . Our findings indicate that bacterially-expressed cytokines are functional in vivo and do induce a unique pattern of responses, quite distinct from that induced by BRD509 organisms . Both the type and magnitude of specific immune parameters were affected . These included the capacity to induce an inflammatory response resulting in a state of profound splenomegaly and hepatomegaly, activation of individual immune cells (particularly macrophages and other myeloid lineage cells), and the induction of nitric oxide (NO) secretion . Furthermore, a structural analysis using light as well as electron microscopy was undertaken to examine the host cellular response to infection with the different bacterial strains . The results indicate that cytokine expression by the invading pathogen can dramatically influence host immunity from a very early stage following infection . These findings may well have important consequences for the potential utilization of bacterial vector-encoded cytokines in immunoregulation in different disease settings. Vaccine, 2002 May 22, 20(17-18), 2249 - 53 Evaluation of 12 stabilizers in a developed attenuated Salmonella Enteritidis vaccine; Barbour EK et al.; The development of a stable live attenuated Salmonella Enteritidis (SE) vaccine, resisting heat stress during transportation and storage in unequipped tropical and subtropical zones of the world, is highly recommended . Twelve stabilizers were individually supplemented into a 9 ml volume of sterile distilled water resulting in concentrations of 1, 2, 3, 4 and 5% . A volume of 1 ml of attenuated live SE vaccine is added over the 9 ml of each concentration of the stabilizers . The differently stabilized SE vaccines were stressed at 55 degrees C for 48 h . The lowest percent reductions in SE cell viability by specified level of each stabilizer in ascending order were: 22.3% by 2% skim milk, 55.1% by 5% bovine serum albumin (BSA), 59.2% by 4% sorbitol, 74.4% by 3% maltose, 75% by 2% honey, 91.3% by 3% histidine, 96.9% by 1% heparin, 97.5% by 4% dextrose, 97.9% by 5% lactose, 99.4% by 5% sucrose, 99.5% by 2% gelatin, and 100% by 1-5% glycerol . In narrowing the concentration levels of skim milk to include 1.00, 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, 2.75, and 3.00%, the 2.50% was the optimum level resulting in minimal percent reduction in SE cell viability of 18.9% after exposure to the defined heat stress. Biol Trace Elem Res, 2002 May, 86(2), 177 - 91 Antimutagenic activity of selenium-enriched green tea toward the heterocyclic amine 2-amino-3-methylimidazo{4,5-f}quinoline; Amantana A et al.; Both selenium and green tea have been reported to exhibit antigenotoxic and cancer chemopreventive properties . We compared the antimutagenic activities of regular green tea and selenium-enriched green tea obtained from Hubei Province, China, toward the heterocyclic amine, 2-amino-3-methylimidazo{4,5-f}quinoline (IQ) in the Salmonella assay . Selenium-enriched green tea obtained by foliar application of selenite exhibited concentration-dependent inhibition of IQ-induced mutagenesis in the presence of rat liver S9 and was significantly more effective than regular green tea tested under the same conditions . Analytical studies revealed no major differences in the polyphenol or caffeine content between regular green tea and selenium-enriched green tea, but the latter tea contained approximately 60-fold higher concentrations of selenium compared with regular green tea . The only soluble form of selenium was identified as selenite . The antimutagenic effects of certain individual tea constituents, such as epicatechin gallate and catechin, were enhanced by the addition of selenite to the Salmonella assay . Sodium selenite, sodium selenate, seleno-DL-cysteine, seleno-L-methionine, and L-Se-methylselenocysteine were not antimutagenic toward IQ when tested alone, but augmented significantly the inhibitory potency of green tea . The results suggested an enhancing ("coantimutagenic") effect of selenium in combination with green tea in vitro, but in vivo studies are needed to assess whether there is a synergistic effect of tea and selenium to protect against heterocyclic amine-induced mutagenesis and carcinogenesis. Microbiol Immunol, 2002, 46(3), 177 - 80 Detection of herpesvirus DNA in the serum of immunocompetent children; Hara S et al.; The DNA of herpesviruses such as Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus-6 (HHV6), and human herpesvirus-7 (HHV7) has been detected in the serum of patients with primary infection or with immunosuppression . However, it is unknown how frequently herpesvirus DNA can be detected in the serum of immunocompetent children, or whether the detection of herpesvirus DNA indicates an active infection or virus-related diseases . Using a real-time polymerase chain reaction assay, attempts were made to detect herpesvirus DNA in the serum of 176 ambulatory children who visited a hospital for various reasons . EBV was detected in 4 (2.2%), HHV6 in 4 (2.2%), and HHV7 in 2 (1.1%) of 176 children, but CMV was not detected . Of the 10 positive patients, only 4 were considered, by virtue of clinical and serological characteristics, to have primary infections . The other 4 positive patients had other infections, such as mycoplasma and salmonella . Although herpesvirus DNA could be detected in the serum of immunocompetent children, there was not always a relationship between clinical manifestations and the detection of virus DNA . When herpesvirus DNA is detected in the serum, a careful interpretation is necessary to diagnose a primary infection or a virus-associated disease. Int J Med Microbiol, 2002 Mar, 291(8), 645 - 8 Modified pulsed-field gel electrophoresis method for DNA degradation-sensitive Salmonella enterica and Escherichia coli strains; Liesegang A et al.; A number of S . enterica and E . coli strains appeared sensitive to a rapid DNA degradation during the course of PFGE pattern analysis . This kind of DNA degradation could not be stopped by intensive treatment with proteinase K, formalin treatment, or other modifications of the protocol for the isolation of intact chromosomal DNA . However, the application of 100 microM thiourea into the running buffer gave rise to clear-cut PFGE patterns and in turn to an overall typeability. Int J Med Microbiol, 2002 Mar, 291(8), 633 - 44 Temperate phages in Salmonella enterica serovar Typhimurium: implications for epidemiology; Mmolawa PT et al.; Salmonella enterica serovar Typhimurium is the most common Salmonella serovar isolated from humans in Australia . The most common definitive phage types (DT) include 9, 64 and 135 . Induction of lysogenic phages from DT 64 with mitomycin C followed by cesium chloride gradient purification, resulted in separation of two populations of phage particles . DNA extracted from these particles that was digested with SmaI showed two distinct patterns of banding . Transmission electron microscopy showed that both phage particles belong to the podovirus family of the C1 morphotype . One of the phages, ST64T is capable of mediating both generalized transduction and bacteriophage type conversion . Crude phage lysate induced from S . Typhimurium DT 64 was capable of phage type conversion . S . Typhimurium DT 9 was converted to DT 64 and DT 135 was converted to DT 16 . S . Typhimurium DT 41 was also converted to DT 29 . Amplified-fragment length polymorphism revealed differences between the original isolates and the convertants . Phage type conversion raises the question of the stability of the bacterial phage types in natural settings and the possibility of its occurrence during an outbreak scenario. Int J Med Microbiol, 2002 Mar, 291(8), 593 - 603 Delivery of dangerous goods: type III secretion in enteric pathogens; Zaharik ML et al.; Type III secretion systems (TTSSs) of Gram-negative pathogens are molecular syringes that inject bacterial virulence factors directly into host cells . These virulence factors manipulate host cell pathways to aid bacterial survival within the host . Four important enteric pathogens use TTSSs to colonize and persist within the intestinal environment . The following is a brief review of the way in which TTSSs and their effectors contribute to the pathogenic nature of the prototypic diarrheal pathogens Salmonella, Shigella, Yersinia and enteropathogenic Escherichia coli (EPEC). Vet Immunol Immunopathol, 2002 Jul, 86(3-4), 251 - 4 Development of a baculovirus expression system for soluble porcine tumor necrosis factor receptor type I and soluble porcine tumor necrosis factor receptor type I-IgG fusion protein; Mwangi SM et al.; Tumor necrosis factor-alpha (TNF-alpha) is a key mediator of inflammatory responses and gram-negative bacterial sepsis, but the role that it plays during Salmonella enterica species bacterial infections in swine has not yet been elucidated . To facilitate studies on the role of TNF-alpha on the pathology associated with Salmonella infections in pigs, recombinant soluble porcine TNF receptor type I (rspTNF-RI) and soluble TNF receptor type I fused to the Fc region of porcine IgG1 (rspTNF-RI-IgG) were expressed in insect cells using a baculovirus expression system . The proteins were secreted into the cell culture media and purified by anti-soluble porcine TNF-RI antibody and protein G affinity chromatography, respectively . The yield of protein using this method was approximately 1.5mg rspTNF-RI and 4mg rspTNF-RI-IgG/L of cell culture medium . In in vitro assays, rspTNF-RI-IgG was approximately 10-fold (0.97 vs . 10.00pmol/ml) more effective than rspTNF-RI at completely inhibiting the cytotoxic activity of 500U of recombinant porcine TNF-alpha on 3 x 10(4) WEHI 164 murine fibrosarcoma, clone 13, cells . Compared to previously described methods, this method yields significantly more biologically active rspTNF-RI. FEMS Microbiol Rev, 2002 Mar, 26(1), 3 - 16 Fluoroquinolone resistance in Salmonella serovars isolated from humans and food animals; Piddock LJ; Quinolone-resistant Salmonella enterica usually contain a mutation in gyrA within the region encoding the quinolone resistance determining region of the A subunit of DNA gyrase . These mutations confer substitutions analogous to Escherichia coli Ser83-->Phe and Asp87-->Gly or Tyr, or a novel mutation resulting in Ala119-->Glu or Val . Mutations in gyrB are rare, and no mutations in parC or parE have been described . Quinolone-resistant Salmonella can also be cross-resistant to other agents including chloramphenicol and tetracycline . Increased efflux has been demonstrated and for some strains this has been associated with increased expression of acrB . Mutation in soxR has also been shown for one isolate . Detection of low level resistance (minimum inhibitory concentrations <0.5 microg ml(-1)) to fluoroquinolones is proving an increasing problem in the treatment of invasive Salmonella infections. Enferm Infecc Microbiol Clin, 2002 May, 20(5), 208 - 11 {Salmonella spp . serotypes isolated at the Hospital Universitario Reina Sofía in Córdoba during an 8-year period, 1993-2000}; Rodriguez Fde C et al.; BACKGROUND: As a producer of gastro-enteritis and other symptoms, Salmonella spp . Remains an important problem for world public health . Epidemiological knowledge at both general and local level by means of serotypification is considered one of the fundamental aspects for its control . MATERIAL AND METHOD: We studied 15.181 stool samples, and the others specimens . Isolation using the usual routine media, agar MacConkey, Salmonella-Shigella, selenito F . Identification using the automated Microscan and wider I method, serotypification with multi-purpose and monospecific serums (Difco), and confirmation of Salmonella and Shigella by the National Reference Laboratory, from the LNRSSE . RESULTS: Although 96.6% of Salmonella spp . Is detected in cultures of faeces and blood, it is also noted in LCR, sputum, rectal biopsy and vaginal secretions among other sites . In total of 1290 patients, 37 different serotypes were isolated, the most frequent of which were Enteritidis and Typhimurium . The presence of Virchow, isolated in both faeces and LCR, was notable in the years 94-99, as was as the presence of less typical serotypes, such as Blockley, London, Give and Mikawasima, among others. J Bacteriol, 2002 Jun, 184(11), 2940 - 50 ArgR-independent induction and ArgR-dependent superinduction of the astCADBE operon in Escherichia coli; Kiupakis AK et al.; For Escherichia coli, growth in the absence of ammonia is termed nitrogen limited and results in the induction of genes that assimilate other nitrogen sources, a response mediated by sigma(54) and nitrogen regulator I (NR(I), also called NtrC) . The astCADBE operon, which is required for growth with arginine as the sole nitrogen source, is moderately expressed during general nitrogen limitation and maximally expressed in the presence of arginine . The operon is also induced in stationary phase . Primer extension analysis of E . coli revealed the presence of a sigma(54)-dependent promoter utilized in exponential phase during nitrogen limitation and a sigma(S)-dependent promoter active during stationary phase . We used an ast-lacZ fusion to show that arginine stimulates expression, that ArgR, the arginine repressor, enhances expression from both promoters but is not essential, and that transcription by the two forms of the RNA polymerase is competitive and mutually exclusive . We demonstrated the binding of RNA polymerase holoenzymes, NR(I), and ArgR to the promoter region in vitro . We also reconstituted transcription from both promoters with purified components, which confirmed the accessory role of ArgR for the sigma(54)-dependent promoter . Thus, the ast operon exhibits nitrogen source-specific induction that is unique for an NR(I)-dependent gene . The transcriptional regulation of the ast operon in E . coli differs from that in Salmonella enterica serovar Typhimurium, in which ArgR is required for ast operon expression. J Bacteriol, 2002 Jun, 184(11), 2857 - 62 Nucleotide and amino acid sequences of oriT-traM-traJ-traY-traA-traL regions and mobilization of virulence plasmids of Salmonella enterica serovars enteritidis, gallinarum-pullorum, and typhimurium; Chu C et al.; The virulence plasmid of Salmonella enterica serovar Gallinarum-Pullorum (pSPV) but not those of Salmonella enterica serovars Enteritidis (pSEV) and Typhimurium (pSTV) can be readily mobilized by an F or F-like conjugative plasmid . To investigate the reason for the difference, the oriT-traM-traJ-traY-traA-traL regions of the three salmonella virulence plasmids (pSVs) were cloned and their nucleotide and deduced amino acid sequences were examined . The cloned fragments were generally mobilized more readily than the corresponding full-length pSVs, but the recombinant plasmid containing the oriT of pSPV was, as expected, more readily mobilized, with up to 100-fold higher frequency than the recombinant plasmids containing the oriT of the other two pSVs . The nucleotide sequences of the oriT-traM-traJ-traY-traA-traL region of pSEV and pSTV were almost identical (only 4 bp differences), but differed from that of pSPV . Major nucleotide sequence variations were found in traJ, traY, and the Tra protein binding sites sby and sbm . sby of pSPV showed higher similarity than that of pSEV or pSTV to that of the F plasmid . The reverse was true for sbm: similarity was higher with pSEV and pSTV than with pSPV . In the deduced amino acid sequences of the five Tra proteins, major differences were found in TraY: pSEV's TraY was 75 amino acids, pSTV's was 106 amino acids, and pSPV's was 133 amino acids; and there were duplicate consensus betaalphaalpha fragments in the TraY of pSPV and F plasmid, whereas there was only a single betaalphaalpha fragment in that of pSEV and pSTV. Br Poult Sci, 2002 Mar, 43(1), 47 - 53 Influence of dietary conjugated linoleic acid isomers on early inflammatory responses in male broiler chickens; Takahashi K et al.; 1 . The influence of dietary conjugated linoleic acid isomer (CLA, 0 and 10 g/kg) on the metabolic and physiological responses to immune stimulation induced by a single injection of Salmonella enteritidis lipopolysaccharide (LPS) or repeated injections of LPS and Sephadex G-50 was determined in male broiler chicks . 2 . In experiment 1, 10-d-old chicks were fed on experimental diets for 14 d and half of the birds fed on each diet were injected intraperitoneally with LPS (1.5 mg/kg body weight) . In experiment 2,7-d-old chicks were fed on experimental diets for 18 d . Immune stimulation was started at 19 d old and continued for 5 d . Half of the birds fed on each diet were injected intraperitoneally with 0.25 mg/kg body weight of LPS at 19, 21 and 23 d of age, and with 250 mg/kg body weight of Sephadex at 20 and 22 d of age to stimulate the immune system . 3 . In experiment 1, giving CLA prevented an increase in blood heterophil to lymphocyte ratio 7 h after a single injection of LPS, and increases in plasma ceruloplasmin and alpha 1 acid glycoprotein (AGP) 24 h after the injection, but not 7 h after the injection . CLA also prevented a decrease in food intake for 24 h after LPS injection . 4 . In experiment 2, the CLA diet partially prevented reductions in body weight gain and weight gain to feed intake ratio caused by repeated injections of LPS and Sephadex . Feeding CLA prevented increases in plasma ceruloplasmin and AGP at 24 d of age caused by repeated injections of LPS and Sephadex, but not at 20 d of age . 5 . These results suggest that feeding CLA alleviates some undesirable metabolic and physiological changes induced by immunological stimulation in male broiler chicks. Br Poult Sci, 2002 Mar, 43(1), 38 - 46 Use of molecular fingerprinting to assist the understanding of the epidemiology of Salmonella contamination within broiler production; Liebana E et al.; 1 . We analysed Salmonella isolates by conventional sero- and phage-typing, as well as by molecular techniques within the broiler production chain in two integrated companies . The most prevalent serovars were selected for genetic fingerprinting . 2 . Isolates were first screened by plasmid profiling; subsequently, the most common plasmid types within the prevalent zoonotic serovars (enteritidis and typhimurium) and S . agama were further characterised by PstI-SphI ribotyping, and XbaI pulsed field gel electrophoresis (PFGE) . 3 . Salmonella binza, S . kedougou, and S . 4,12:d:- were endemic in the feed mills over long periods of time, and a variety of plasmid types for each of the serovars were found in the premises . 4 . A similar situation was found with S . binza and S . senftenberg within the hatchery in company B . The Salmonella serovars which were resident in those locations were also the ones most widely distributed throughout the broiler flocks . 5 . Plasmid profiling was useful to subdivide clusters of isolates within serovars, but for each serovar a high percentage (36 to 79%) of the isolates tested fall within a prevalent plasmid type . 6 . A more detailed genetic analysis of the isolates by a multiple typing approach allowed for further strain differentiation, and allowed some epidemiological conclusions to be drawn. Microb Drug Resist, 2002 Spring, 8(1), 1 - 8 Composite integron array generated by insertion of an ORF341-type integron within a Tn21-like element; Villa L et al.; Two class 1 integrons, In-t1 and In-t2, were previously identified in IncFI plasmids of Salmonella enterica serotype Typhimurium . Molecular analysis revealed a close physical link between the two integrons . In-t1 is preceded by the transposase genes of Tn21, whereas In-t2 is located downstream the 3'-conserved segment (3'-CS) of In-t1, in a head-to-tail configuration . In-t1 shows a peculiar sequence downstream the 3'-CS, containing an extended version of the open reading frame known as ORF341 (referred to as ORF341E) and a novel trimethoprim resistance gene, designated dfrA18 . Retrospective analysis provided evidence for In-t1 insertion within Tn1935, a Tn21-related transposon identified in IncFI plasmids circulating among epidemic clones of multidrug-resistant S . enterica during the 1970s . Structural comparison between Tn21 derivatives from recent and ancestor IncFI plasmids showed that In-t2 has been conserved by these replicons . In-t1 belongs to a novel family of class 1 integrons containing the ORF341E sequence, and appears to have been acquired by IncFI plasmids after the assembly of Tn1935 . In-t1 insertion occurred within the 5'-conserved segment (5'-CS) proximal region of the resident In-t2. Epidemiol Infect, 2002 Apr, 128(2), 333 - 6 IS200 fingerprinting of Salmonella enterica serotype Abortusovis strains isolated in Iran; Nikbakht GH et al.; Salmonella enterica serovar Abortusovis is one of the most common pathogens responsible for abortion in sheep . In Iran, the spread of Abortusovis is highly dependent on the nomadic life style . In this study we performed IS200 fingerprinting to identify the clonal lines circulating in Iran . All the isolates contained 4 or 5 copies of the transposon and could be classified in 4 genotypes . A single genotype was highly prevalent and very likely it has circulated in Iran since 1970 . All the isolates showed a high degree of relatedness. Epidemiol Infect, 2002 Apr, 128(2), 119 - 30 Phage typing and PFGE pattern analysis as tools for epidemiological surveillance of Salmonella enterica serovar Bovismorbificans infections; Liesegang A et al.; Some years ago, an increase in the number of sporadic cases and outbreaks of salmonellosis due to S . enterica serovar Bovismorbificans was observed in several European countries including Finland, Sweden, England/Wales, Austria, and Germany . In order to understand the recent spread of this serovar and to trace the route of infection back to its source, it was considered necessary to subtype S . Bovismorbificans isolates . Using phage typing (newly described here) and molecular fingerprinting (PFGE-pattern, plasmid profiles and ribotype) the isolates of European origin could be subtyped and compared to S . Bovismorbificans isolates that originated in overseas countries such as Australia, Thailand, India, etc . where this serovar was isolated more frequently . Significant clonal diversity was identified but some of the clonal types of S . Bovismorbificans dominated the epidemics and single cases in Europe as well as in overseas countries . The clonal identity among these isolates indicates an international distribution, new sources of infection, and highlights the urgent requirement for standardized laboratory based surveillance networks (e.g . Enter-Net) . Moreover, it is suggested that strains of S . Bovismorbificans will continue to be of concern in public health and that phage typing together with PFGE typing can be applied as reliable and rapid tools for their future monitoring. Chemosphere, 2002 Feb, 46(5), 757 - 77 The toxicology of the three commercial polybrominated diphenyl oxide (ether) flame retardants; Hardy ML; Three commercial polybrominated diphenyl oxide flame retardants (PBDPO, PBDE) are manufactured: decabromodiphenyl oxide (DBDPO), octabromodiphenyl oxide (OBDPO) and pentabromodiphenyl oxide (PeBDPO) . The composition, production volumes, uses and toxicology of the three products differ . In 1999, DBDPO accounted for approximately 82% of the global PBDPO usage . DBDPO has been extensively tested . DBDPO was not acutely toxic, was not irritating to the skin or eye, and did not induce skin sensitization . No evidence of genotoxic effects was detected in the Ames Salmonella, chromosome aberration, mouse lymphoma, or sister chromatid exchange tests . No cytogenic changes were observed in the bone marrow of rats (parents and offspring) undergoing a one-generation reproduction test . DBDPO did not adversely affect development or reproduction in rats . DBDPO's no-adverse-effect-level (NOAEL) in repeated dose studies was > or = 1000 mg/kg body weight . No, equivocal, or some evidence of carcinogenicity, dependent on genus and sex, was found in mice and rats at 2.5% and 5% of the diet administered for 2 years . DBPDO was poorly absorbed from the gastrointestinal tract (< 0.3-2% oral dose), had a short half-life (< 24 h) compared to PCB 153 (only 2% of an oral dose eliminated by rats in 21 days), and was rapidly eliminated via the feces (> 99% in 72 h) . In contrast, components of the PeBDPO product were well absorbed and slowly eliminated, OBDPO's effect level in a 90-day study was approximately 100 mg/kg, PeBDPO's no-effect-level (NOEL) in a 30-day study was 1 mg/kg, and OBDPO induced developmental toxicity in the rat . In aquatic species, neither DBDPO nor OBDPO were toxic to aquatic organisms or bioconcentrating . Components of the PeBDPO product bioconcentrated in fish but produced little evidence of adverse effects. Int J Food Microbiol, 2002 May 5, 75(1-2), 71 - 87 Sensitivity analysis of Salmonella enteritidis levels in contaminated shell eggs using a biphasic growth model; Latimer HK et al.; Salmonella enteritidis (SE) is a common foodbome pathogen, the transmission of which is primarily associated with the consumption of contaminated Grade A shell eggs . In order to estimate the level of SE present in raw shell eggs, it is necessary to consider the protective effects of the egg albumin, which effectively inhibits SE growth in a time- and temperature-dependent manner . In this study, a SE growth model was produced by combining two mathematical equations that described both the extended lag phase of SE growth (food component) and a SE growth model (pathogen component) . This biphasic growth model was then applied to various egg handling scenarios based on the farm-to-table continuum, including in-line and off-line processing facilities with consideration of key events in production, processing, transportation, and storage . Seasonal effects were also studied . Monte Carlo simulation was used to characterize variability in temperature and time parameter values influencing the level of SE to which individuals are exposed . The total level of SE consumed was estimated under best, most likely, and time-temperature abusive handling scenarios . The model estimated that, in most cases, there was no SE growth in contaminated eggs handled under most likely practices, because 10-70% of the yolk membrane remained intact . Under abusive handling scenarios, complete loss of yolk membrane integrity frequently occurred by the time eggs reach the distribution phase, followed by subsequent SE growth, which was often quite rapid . In general, the effect of season and processing method (in-line vs . off-line) was minimal . Further sensitivity analysis demonstrated that the initial SE contamination level significantly influenced the final exposure levels only under no-abuse or mildly abusive conditions . The results of our study suggest that, for maximum reduction of SE exposure level, cooling strategies should not only focus on the on-farm or processing phases, but should emphasize the importance of cooling strategies at the distribution and consumer phases of the farm-to-fork continuum. Dtsch Tierarztl Wochenschr, 2002 Apr, 109(4), 157 - 60 {The influence of viscosity on adhesion and invasion of Salmonella strains in an in vitro model}; Dinjus U et al.; The influence of viscosity on the adhesion and invasion behaviour of Salmonella strains of different origin was investigated using an in-vitro-model . These processes seem to be strain-dependent . Compared to the controls, the number of internalized Salmonella was elevated . This increase was a result of the greater number of Salmonella which adhered to Caco-2-cells and was detected only for strains from organs of calves having died from salmonellosis . The average motility of these strains was determined to be 1.6 +/- 0.5 mm/h . A possible association between adhesion ability and motility was discussed. Emerg Infect Dis, 2002 May, 8(5), 514 - 5 Increasing quinolone resistance in Salmonella enterica serotype Enteritidis; Molbak K et al.; Until recently, Salmonella enterica serotype Enteritidis has remained sensitive to most antibiotics . However, national surveillance data from Denmark show that quinolone resistance in S . Enteritidis has increased from 0.8% in 1995 to 8.5% in 2000 . These data support concerns that the current use of quinolone in food animals leads to increasing resistance in S . Enteritidis and that action should be taken to limit such use. Vet Rec, 2002 Apr 13, 150(15), 471 - 4 Serovars of Salmonella isolated from Danish turkeys between 1995 and 2000 and their antimicrobial resistance; Pedersen K et al.; The prevalence of Salmonella serovars and their antimicrobial resistance patterns were investigated among Danish turkeys between 1995 and 2000, by sampling the flocks approximately 14 days before they were slaughtered . Within the flocks, the prevalence of salmonella varied from 7.1 per cent to 25 per cent, and 24 different serovars were detected . The five most prevalent, which accounted for 58.5 per cent of the isolates were Salmonella Heidelberg (16.2 per cent of the isolates), Salmonella Agona (15.8 per cent), Salmonella Derby (12.4 per cent), Salmonella Muenster (7.3 per cent) and Salmonella Anatum (6.8 per cent) . In addition, a few rough isolates and isolates belonging to the antigenically incomplete formulae 6,7:-:- and 4,12:b:- were found . The level of antimicrobial resistance was low; the highest resistance was recorded to ampicillin (13.7 per cent) and streptomycin (9.0 per cent) followed by tetracycline (8.5 per cent), sulphonamides (7.7 per cent) and spectinomycin (4.7 per cent) . Resistance to quinolones was very low: four isolates were resistant to nalidixic acid, and only one was resistant to enrofloxacin . No resistance was recorded to colistin, apramycin, ceftiofur, florfenicol, or amoxycillin with clavulanic acid . Only 24 isolates were resistant to two or more compounds in various combinations of up to six compounds; one Salmonella Havana isolate was resistant to six compounds . Six isolates were serovar Typhimurium, but none of them belonged to phage type DT104. J AOAC Int, 2002 Mar-Apr, 85(2), 395 - 403 Comparison of assurance gold salmonella EIA, BAX for screening/Salmonella, and GENE-TRAK Salmonella DLP rapid assays for detection of Salmonella in alfalfa sprouts and sprout irrigation water; Stewart DS et al.; The Assurance Gold Salmonella EIA, BAX for Screening/Salmonella, and GENE-TRAK Salmonella DLP rapid assays were compared with official cultural methods described in the Bacteriological Analytical Manual (BAM) for analysis of alfalfa sprouts and sprout irrigation water for the presence of Salmonella . The lower limits of detection of 4 serovars of Salmonella cells (S . tennessee, S . muenchen, S . mbandanka, and S . cubana) in pure culture were determined as approximately log10 2, 5, and 6 for the BAX, GENE-TRAK, and Gold EIA, respectively . Despite its low detection limit, the BAX did not perform as well as the other assays in analyzing contaminated sprouts and sprout irrigation water . For 4 different lots of sprouts and sprout irrigation water samples inoculated with the 4 serovars at low {1-2 colony forming units (CFU/g)} and high (68-180 CFU/g) levels, the BAX detected Salmonella in 58/64 (90.6%) of the samples, compared with 64/64 (100%) by the GENE-TRAK, Gold EIA, and BAM methods . Assay performance was also compared for analysis of naturally contaminated sprouts and sprout irrigation water with 3 lots of alfalfa sprouted seeds associated with different salmonellosis outbreaks . Positive assay results for the naturally contaminated samples were Gold EIA 41, GENE-TRAK 36, BAM 33, and BAX 13. J AOAC Int, 2002 Mar-Apr, 85(2), 384 - 7 Enhanced recovery of Salmonella from apple cider and apple juice with universal preenrichment broth; Hammack TS et al.; A comparison was made of the relative efficiencies of Universal Preenrichment (UP) broth and lactose broth for the recovery of a variety of Salmonella serovars from pasteurized and unpasteurized apple cider and pasteurized apple juice . Bulk portions of juice were contaminated with single Salmonella serovars at high and low levels of 0.4 and 0.04 CFU/mL, respectively . The juice was aged for a minimum of 5 days at 2-5 degrees C . On the day analysis was initiated, each of 20 test portions (25 mL) of the contaminated juice was preenriched in UP broth and in lactose broth . The Bacteriological Analytical Manual Salmonella culture method was followed thereafter . For pasteurized apple cider, UP broth recovered significantly (p < 0.05) more Salmonella-positive test portions than did lactose broth (112 and 75, respectively) . For unpasteurized apple cider, UP broth recovered significantly more Salmonella-positive test portions than did lactose broth (326 and 221, respectively) . For pasteurized apple juice, UP broth recovered more Salmonella-positive test portions than did lactose broth (93 and 81, respectively) . However, this difference was not statistically significant . These results indicate that UP broth should replace lactose broth for the analysis of pasteurized and unpasteurized apple cider and pasteurized apple juice. Eur J Biochem, 2002 Apr, 269(8), 2162 - 7 Bromoperoxidase activity of vanadate-substituted acid phosphatases from Shigella flexneri and Salmonella enterica ser . typhimurium; Tanaka N et al.; Vanadium haloperoxidases and the bacterial class A nonspecific acid phosphatases have a conserved active site . It is shown that vanadate-substituted recombinant acid phosphatase from Shigella flexneri (PhoN-Sf) and Salmonella enterica ser . typhimurium (PhoN-Se) in the presence of H2O2 are able to oxidize bromide to hypobromous acid . Vanadate is essential for this activity . The kinetic parameters for the artificial bromoperoxidases have been determined . The Km value for H2O2 is about the same as that for the vanadium bromoperoxidases from the seaweed Ascophyllum nodosum . However, the Km value for Br- is about 10-20 times higher, and the turnover values of about 3.4 min-1 and 33 min-1 for PhoN-Sf and PhoN-Se, respectively, are much slower, than those of the native bromoperoxidase . Thus, despite the striking similarity in the active-site structures of the vanadium haloperoxidases and the acid phosphatase, the turnover frequency is low, and clearly the active site of acid phosphatases is not optimized for haloperoxidase activity . Like the native vanadium bromoperoxidase, the vanadate-substituted PhoN-Sf and PhoN-Se catalyse the enantioselective sulfoxidation of thioanisole. Vaccine, 2002 May 6, 20(15), 1968 - 74 Development of an oral prime-boost strategy to elicit broadly neutralizing antibodies against HIV-1; Devico AL et al.; Given the increasing incidence of HIV-1 infection world-wide, an affordable, effective vaccine is probably the only way that this virus will be contained . Accordingly, our group is developing an oral prime-boost strategy with the primary goal of eliciting broadly neutralizing antibodies against HIV-1 to provide sterilizing immunity for this virus . Our secondary goal is to elicit broadly cross-reactive anti-viral CD8(+) T cells by this strategy to blunt any breakthrough infections that occur after vaccination of individuals who fail to develop sterilizing immunity . This article describes our progress in the use of the live attenuated intracellular bacteria, Salmonella and Shigella, as oral delivery vehicles for DNA vaccines and the development of conformationally constrained HIV-1 Env immunogens that elicit broadly neutralizing antibodies. Plasmid, 2002 Mar, 47(2), 108 - 19 Attenuated Salmonella enterica serovar typhi live vector with inducible chromosomal expression of the T7 RNA polymerase and its evaluation with reporter genes; Santiago-Machuca AE et al.; Attenuated Salmonella strains with defined gene deletions have been extensively evaluated as suitable live carriers of passenger antigens . A number of strategies for antigen delivery by these strains have been attempted, ranging from plasmid-based to chromosomal integration systems . We report here the chromosomal integration of the T7 RNA polymerase gene (T7pol) in the attenuated strain Salmonella enterica serovar Typhi (Salmonella typhi) CVD908 (aroC(-), aroD(-)) . The T7pol gene was amplified by PCR from Escherichia coli BL21(DE3) and cloned in the pNir3 plasmid under the control of the anaerobically inducible nirB promoter . Then it was subcloned in a pKTN701 derivative, suicide plasmid with the R6K ori, and flanked by the aroC gene . After evaluation of its functionality in E . coli SY327, the aroC-T7pol-aroC cassette was integrated into the aroC locus of S . typhi CVD908 by homologous recombination . The resulting strain, S . typhi CVD908-T7pol, was able to transcomplement two plasmids bearing the luc or the lacZ reporter genes controlled by the T7 promoter and produce luciferase and beta-galactosidase under anaerobic culture conditions . Therefore, an inducible system for recombinant antigen production in attenuated S . typhi was achieved . Int J Food Microbiol, 2002 Apr 5, 74(3), 229 - 38 Detection of bacteria using foreign DNA: the development of a bacteriophage reagent for Salmonella; Kuhn J et al.; A phage-based reagent was developed for the detection of Salmonella in food samples . The parental phage was Felix 01, which lyses practically all Salmonella . Using data obtained about the molecular biology of the phage, a recombinant phage that carried the bacterial genes specifying luciferase was produced . The method involved the isolation of amber nonsense mutations and subsequent crosses to render doubly mutant phage with a very low reversion rate on strains lacking an amber suppressor . A plasmid was constructed that contained a segment of Felix 01 DNA with two adjacent genes, one dispensable and the other essential, and their flanking sequences . Recombinant DNA technology was used to remove the two genes and the luxA and luxB genes for luciferase, and a gene specifying a tRNA that recognizes amber codons (supF=tyrT) was put in their stead . This region could be transferred into the genome of the phage by homologous recombination . The recombinant phage cannot grow because it lacks an essential gene . However, it can grow in a host that synthesizes the missing protein . This technique allows the construction of "locked" recombinant phages that carry foreign DNA but which cannot propagate themselves in nature. Int J Food Microbiol, 2002 Apr 5, 74(3), 217 - 27 A bacteriophage reagent for Salmonella: molecular studies on Felix 01; Kuhn J et al.; Felix 01 (F01) is a bacteriophage originally isolated by Felix and Callow which lyses almost all Salmonella strains and has been widely used as a diagnostic test for this genus . Molecular information about this phage is entirely lacking . In the present study, the DNA of the phage was found to be a double-stranded linear molecule of about 80 kb . 11.5 kb has been sequenced and in this region A + T content is 60% . There are relatively few restriction endonuclease cleavage sites in the native genome and clones show this is due to their absence rather than modification . A restriction map of the genome has been constructed . The ends of the molecule cannot be ligated although they contain 5' phosphates . At least 60% of the genome must encode proteins . In the sequenced portion, many open reading frames exist and these are tightly packed together . These have been examined for homology to published proteins but only 1 to 17 shows similarity to known proteins . F01 is therefore the prototype of a new phage family . On the basis of restriction sites, codon usage and the distribution of nonsense codons in the unused reading frames, a strong case can be made for natural selection that reacts to mRNA structure and function. Int J Food Microbiol, 2002 Apr 5, 74(3), 189 - 94 The importance of RpoS in the survival of bacteria through food processing; Dodd CE et al.; The resistance of bacteria to environmental stresses is recognised as an increasingly important area of microbiology . In particular, the alternative sigma factor RpoS has been shown to produce greater stress resistance in stationary phase cells of Salmonella and Escherichia coli compared with those in exponential phase . Our work has shown that RpoS can be induced in exponential phase in response to a number of inimical processes used in the food industry, including changes in water activity produced using a range of humectants and preservatives . The presence of high levels of competitor cells will also lead to early induction of RpoS in Salmonella by an as yet unknown mechanism . High levels of competitor cells also provide Salmonella with an increased resistance to heat and freeze-thaw injury; the mechanism for this, however, is rpoS independent and has lead to the theory of a holistic mechanism for sub-lethal injury in respiring bacteria--the bacterial suicide response . This hypothesis predicts that sub-lethal injury occurs through the production of free radical species and not by the action of the applied inimical process per se . The demonstration of the production of a free radical burst when cells are subjected to differing types of stresses has been shown by a number of methods. J Endotoxin Res, 2002, 8(1), 59 - 67 IL-1 regulates in vivo C-X-C chemokine induction and neutrophil sequestration following endotoxemia; Calkins CM et al.; The influx of neutrophils into tissues in response to inflammatory stimuli involves C-X-C chemokines . Interleukin-1 (IL-1) stimulates chemokine production in vitro, but its role in vivo on chemokine production is not as clearly understood . We hypothesized that IL-1 mediates in vivo tissue C-X-C chemokine production induced by systemic lipopolysaccharide (LPS) . IL-1 activity was blocked by IL-1 receptor antagonist (IL-1Ra) . Rats were injected with Salmonella typhi LPS (0.5 mg/kg) with and without prior administration of IL-1Ra . Cytokine-induced neutrophil chemoattractant-1 (CINC-1) and macrophage inflammatory protein-2 (MIP-2) protein and mRNA levels, tissue neutrophil accumulation, and indices of organ injury were measured . LPS administration resulted in increased plasma, lung, and liver IL-1beta that was decreased by Il-1Ra . LPS also induced an increase in plasma, lung, and liver CINC-1 and MIP-2 protein and mRNA . However, IL-1Ra had no effect on LPS-induced plasma or lung tissue CINC-1 levels . In contrast, IL-1Ra pretreatment did significantly decrease CINC-1 protein expression in the liver (45% decrease) and MIP-2 protein expression in plasma (100% decrease), lung (72% decrease) and liver (100% decrease) compared to LPS- treated controls . Steady-state mRNA levels by Northern blot analysis of both CINC-1 and MIP-2 in lung and liver were similar to the protein findings . Pretreatment with IL-1Ra also resulted in a 47% and 59% decrease in lung and liver neutrophil accumulation, respectively, following LPS . In addition, indices of both lung and liver injury were decreased in animals pretreated with IL-1Ra . In summary, LPS induces IL-1beta and MIP-2 expression in the lung and liver, both of which are IL-1 dependent . Although lung neutrophil accumulation in both lung and liver after LPS is also IL-1 mediated, lung CINC-1 levels were unaffected by IL-1Ra . These data suggest that IL-1 regulates tissue chemokine expression and neutrophil accumulation after LPS. J Clin Microbiol, 2002 May, 40(5), 1626 - 35 Multilocus sequence typing for characterization of clinical and environmental salmonella strains; Kotetishvili M et al.; Multilocus sequence typing (MLST) based on the 16S RNA, pduF, glnA, and manB genes was developed for Salmonella, and its discriminatory ability was compared to those of pulsed-field gel electrophoresis (PFGE) and serotyping . PFGE differentiated several strains undifferentiable by serotyping, and 78 distinct PFGE types were identified among 231 Salmonella isolates grouped into 22 serotypes and 12 strains of undetermined serotype . The strains of several PFGE types were further differentiated by MLST, which suggests that the discriminatory ability of MLST for the typing of Salmonella is better than that of serotyping and/or PFGE typing . manB-based sequence typing identified two distinct genetic clusters containing 32 of 54 (59%) clinical isolates whose manB gene sequences were analyzed . The G+C contents and Splitstree analysis of the manB, glnA, and pduF genes of Salmonella indicated that the genes differ in their evolutionary origins and that recombination played a significant role in their evolution. Med Trop (Mars), 2001, 61(6), 491 - 4 {Management of typhoid perforation of the small bowel: a case series in Western French Guiana}; Mallick S et al.; The purpose of this retrospective study of a five-year period in western French Guiana is to report our experience in the management of small bowel perforation due to Salmonella typhi and to underline the main diagnostic and therapeutic pitfalls . Even if clinical and laboratory findings were compatible, final diagnosis was reserved until confirmation by postoperative bacteriological findings . In patients without advanced peritonitis, excellent results can be achieved by excision of the edges of the lesion followed by direct suture in cases involving single perforations and by segmental resection followed by end-to-end anastomosis in cases involving multiple perforations . However these techniques cannot be extended to patients presenting severe peritonitis who must be treated by bowel diversion. Folia Microbiol (Praha), 2002, 47(1), 43 - 50 Copper-resistant bacteria from industrial effluents and their role in remediation of heavy metals in wastewater; Shakoori AR et al.; Six copper-resistant bacterial strains were isolated from wastewater of tanneries of Kasur and Rohi Nala . Two strains tolerated copper at 380 mg/L, four up to 400 mg/L . Three strains were identified as members of the genus Salmonella; one strain was identified as Streptococcus pyrogenes, one as Vagococcus fluvialis and the last was identified as Escherichia coli . The pH and temperature optimum for two of them were 7.0 and 30 degrees C, respectively; four strains had corresponding optima at 7.5 and 37 degrees C, respectively . All bacterial isola-tes showed resistance against Ag+ (280-350 mg/L), Co2+ (200-420), CrVI (280-400), Cd2+ (250-350), Hg2+ (110-200), Mn2+ (300-380), Pb2+ (300-400), Sn2+ (480-520) and Zn2+ (300-450) . Large-sized plasmids (> 20 kb), were detected in all of the strains . After the isolates were cured of plasmids with ethidium bromide, the efficiency of curing was estimated in the range of 60-90% . Reference strain of E . coli was transformed with the plasmids of the bacterial isolates which grew in Luria-Bertani medium containing 100 mg/L Cu2+ . The capability to adsorb and afterwards accumulate Cu2+ inside their cells was assayed by atomic absorption spectrophotometer; all bacterial cells had the ability to adsorb 50-80% of the Cu2+ and accumulate 30-45% Cu2+ inside them after 1 d of incubation. Fitoterapia, 2002 Apr, 73(2), 160 - 4 Antimicrobial and phytochemical studies of Swertia corymbosa; Ramesh N et al.; The aqueous, methanol, chloroform and hexane extracts of Swertia corymbosa were tested (in vitro) for their antimicrobial efficiency . Maximum inhibitory activity was noticed against Staphylococcus aureus and Salmonella typhi. Arch Microbiol, 2002 May, 177(5), 410 - 9 Epub 2002 Mar 16. Two class II D-tagatose-bisphosphate aldolases from enteric bacteria; Brinkkotter A et al.; Escherichia coli, Salmonella enterica, Klebsiella pneumoniaeand Klebsiella oxytocawere found to contain two D-tagatose 1,6-bisphosphate (TagBP)-specific aldolases involved in catabolism of galactitol (genes gatY gatZ) and of N-acetyl-galactosamine and D-galactosamine (genes kbaY kbaZ,also called agaY agaZ) . The two aldolases were closely related (> or = 53.8% identical amino acids) and could substitute for each other in vivo . The catalytic subunits GatY or KbaY alone were sufficient to show aldolase activity . Although substantially shorter than other aldolases (285 amino acids, instead of 358 and 349 amino acids), these subunits contained most or all of the residues that have been identified as essential in substrate/product recognition and catalysis for class II aldolases . In contrast to these, both aldolases required subunits GatZ or KbaZ (420 amino acids) for full activity and for good in vivo and in vitro stability . The Z subunits alone did not show any aldolase activity . Close relatives of these new TagBP aldolases were found in several gram-negative and gram-positive bacteria, e.g., Streptomyces coelicolor. Acta Crystallogr D Biol Crystallogr, 2002 May, 58(Pt 5), 798 - 804 Epub 2002 Apr 26. Comparison of different crystal forms of 3-dehydroquinase from Salmonella typhi and its implication for the enzyme activity; Lee WH et al.; The type I 3-dehydroquinate dehydratase (DHQase) which catalyses the reversible dehydration of 3-dehydroquinic acid to 3-dehydroshikimic acid is involved in the shikimate pathway for the biosynthesis of aromatic compounds . The shikimate pathway is absent in mammals, which makes structural information about DHQase vital for the rational design of antimicrobial drugs and herbicides . The crystallographic structure of the type I DHQase from Salmonella typhi has now been determined for the native form at 1.78 A resolution (R = 19.9%; R(free) = 24.7%) . The structure of the modified enzyme to which the product has been covalently bound has also been determined but in a different crystal form (2.1 A resolution; R = 17.7%; R(free) = 24.5%) . An analysis of the three available crystal forms has provided information about the physiological dimer interface . The enzyme relies upon the closure of a lid-like loop to complete its active site . As the lid-loop tends to stay in the closed position, dimerization appears to play a role in biasing the arrangement of the loop towards its open position, thus facilitating substrate access. J Bacteriol, 2002 May, 184(10), 2833 - 6 Bacteriophage SP6 is closely related to phages K1-5, K5, and K1E but encodes a tail protein very similar to that of the distantly related P22; Scholl D et al.; The lytic salmonella phage SP6 encodes a tail protein with a high degree of sequence similarity to the tail protein of the biologically unrelated lysogenic salmonella phage P22 . The SP6 tail gene is flanked by an upstream region that contains a promoter and a downstream region that contains a putative Rho-independent transcription terminator, giving it a cassette or modular structure almost identical to the structure of the tail genes of coliphages K1E, K5, and K1-5 . It now appears that SP6, K1-5, K5, and K1E are very closely related but have different tail fiber proteins, giving them different host specificities. J Bacteriol, 2002 May, 184(10), 2827 - 32 Elevated levels of ketopantoate hydroxymethyltransferase (PanB) lead to a physiologically significant coenzyme A elevation in Salmonella enterica serovar Typhimurium; Rubio A et al.; Pantothenate is the product of the ATP-dependent condensation of pantoate and beta-alanine and is a direct precursor of coenzyme A . A connection exists between pantothenate biosynthesis and thiamine biosynthesis in Salmonella enterica serovar Typhimurium since derivatives of a purF mutant that can grow (on glucose medium) in the absence of thiamine excrete pantothenate . We show here that the causative mutation in three such mutants was the addition of a CG base pair upstream of the panB gene . This base addition brings the spacing between the -10 and -35 hexamers of the promoter to a consensus spacing of 17 bp and results in increased transcription of the pan operon . Furthermore, overexpression of PanB caused by this mutation, or by other means, was necessary and sufficient to increase pantothenate production and allow PurF-independent thiamine synthesis on glucose medium. J Bacteriol, 2002 May, 184(10), 2626 - 33 The evolving genome of Salmonella enterica serovar Pullorum; Liu GR et al.; Salmonella enterica serovar Pullorum is a fowl-adapted bacterial pathogen that causes dysentery (pullorum disease) . Host adaptation and special pathogenesis make S . enterica serovar Pullorum an exceptionally good system for studies of bacterial evolution and speciation, especially regarding pathogen-host interactions and the acquisition of pathogenicity . We constructed a genome map of S . enterica serovar Pullorum RKS5078, using I-CeuI, XbaI, AvrII, and SpeI and Tn10 insertions . Pulsed-field gel electrophoresis was employed to separate the large DNA fragments generated by the endonucleases . The genome is 4,930 kb, which is similar to most salmonellas . However, the genome of S . enterica serovar Pullorum RKS5078 is organized very differently from the majority of salmonellas, with three major inversions and one translocation . This extraordinary genome structure was seen in most S . enterica serovar Pullorum strains examined, with different structures in a minority of S . enterica serovar Pullorum strains . We describe the coexistence of different genome structures among the same bacteria as genomic plasticity . Through comparisons with S . enterica serovar Typhimurium, we resolved seven putative insertions and eight deletions ranging in size from 12 to 157 kb . The genomic plasticity seen among S . enterica serovar Pullorum strains supported our hypothesis about its association with bacterial evolution: a large genomic insertion (157 kb in this case) disrupted the genomic balance, and rebalancing by independent recombination events in individual lineages resulted in diverse genome structures . As far as the structural plasticity exists, the S . enterica serovar Pullorum genome will continue evolving to reach a further streamlined and balanced structure. Mol Microbiol, 2002 Apr, 44(2), 561 - 71 Mg2+ homeostasis and avoidance of metal toxicity; Chamnongpol S et al.; Because Mg2+ is required for a wide variety of cellular functions, its intracellular levels must be tightly regulated . In the Gram-negative bacterium Salmonella enterica, three transporters mediate Mg2+ uptake: the P-type ATPases MgtA and MgtB, whose expression is transcriptionally induced in low Mg2+ by the Mg2+-regulated PhoP/PhoQ two-component system; and CorA, whose transcription is regulated neither by the levels of Mg2+ nor by the PhoP/PhoQ system . We now report that mutants defective in phoP or in both mgtA and mgtB are hypersensitive to oxidative stress-dependent Fe (II)-mediated killing . These mutants display increased iron accumulation and heightened Ni2+ uptake . Inactivation of the corA gene restored Fe(II) resistance to the phoP mutant and eliminated uptake of Ni2+ . Neither corA transcription nor CorA protein levels were altered in the phoP mutant, suggesting that CorA alters its activity in response to the presence of PhoP-regulated determinants . Downregulation of CorA activity in low Mg2+ environments may enable Salmonella to avoid the uncontrolled influx of toxic metals. J Appl Microbiol, 2002, 92(5), 893 - 902 Washing and chilling as critical control points in pork slaughter hazard analysis and critical control point (HACCP) systems; Bolton DJ et al.; AIMS: The aim of this research was to examine the effects of preslaughter washing, pre-evisceration washing, final carcass washing and chilling on final carcass quality and to evaluate these operations as possible critical control points (CCPs) within a pork slaughter hazard analysis and critical control point (HACCP) system . METHODS AND RESULTS: This study estimated bacterial numbers (total viable counts) and the incidence of Salmonella at three surface locations (ham, belly and neck) on 60 animals/carcasses processed through a small commercial pork abattoir (80 pigs d(-1)) . Significant reductions (P < 0.05) in bacterial numbers were noted at some stages of the slaughter/dressing process, i.e . the process of hair removal (scalding-dehairing and singeing) resulted in an approx . 4.5 log10 cfu cm(-2) decrease in bacterial numbers . A significant increase (P < 0.05) in bacterial numbers was observed after pre-evisceration washing . Final washing increased the bacterial counts to between 3.6 and 3.8 log10 cfu cm(-2) while chilling effected a small but statistically significant (P < 0.05) increase to between 4.5 and 4.7 log10 cfu cm(-2) . The incidence of Salmonella on pigs at the farm was 27%, decreasing to 10% after preslaughter washing . However, stunning and bleeding effected a considerable increase in Salmonella contamination and the incidence after these operations was 50%, which was reduced to 0% during the scalding-dehairing process . CONCLUSIONS: Washing the live animals and subsequent carcasses with cold water is not an effective control measure but chilling may be used as a CCP . SIGNIFICANCE AND IMPACT OF THE STUDY: Recent changes in European Union legislation legally mandate HACCP in pork slaughter plants . This research will provide a sound scientific basis on which to develop and implement effective HACCP in pork abattoirs. J Infect, 2002 Jan, 44(1), 44 - 7 Chronic relapsing salmonella osteomyelitis in an immunocompetent patient: case report and literature review; Banky JP et al.; We present the first case of Salmonella virchow causing a relapsing bone infection at the same site 12 years apart in an otherwise healthy patient . Chronic relapsing osteomyelitis caused by a zoonotic salmonella may become increasingly important in view of the increased incidence of zoonotic salmonella infections . Based on this case, we recommend 3 months of therapy with a quinolone when treating a chronic relapsing zoonotic salmonella osteomyelitis . Nucleic Acids Res, 2002 May 1, 30(9), 1985 - 90 Insertions in the anticodon loop of tRNA1Gln(sufG) and tRNA(Lys) promote quadruplet decoding of CAAA; O'Connor M; Base insertion mutations in the anticodons of two different Escherichia coli tRNAs have been isolated that allow suppression of a series of +1 frameshift mutations . Insertion of a U between positions 34 and 35 of tRNAGln1 or addition of a G between positions 36 and 37 of tRNA(Lys) expand the anticodons of both tRNAs similarly to 3'-GUUU(-5') and allow decoding of complementary 5'-CAAA(-3') quadruplets . Analysis of the suppressed mRNA sequences suggests that suppression occurs by pairing of the expanded anticodons to all four bases of the complementary, quadruplet codon . The tRNA Gln mutants are identical to the sufG class of frameshift suppressors isolated both in Salmonella enterica serovar Typhimurium and E . coli by Kohno and Roth and previously thought to affect tRNA(Lys). Mutagenesis, 2002 May, 17(3), 257 - 60 Fumonisin B(1) is genotoxic in human derived hepatoma (HepG2) cells; Ehrlich V et al.; Fumonisin B(1) (FB(1)), a widespread Fusarium toxin which is frequently found in corn, causes liver tumors in laboratory rodents and is a suspected human carcinogen . The compound was tested in micronucleus (MN) and single cell gel electrophoresis (SCGE) assays in human derived hepatoma (HepG2) cells and caused a pronounced dose-dependent genotoxic effect at exposure concentrations > or = 25 microg/ml . In contrast, no induction of his(+) revertants was found in Salmonella microsome assays with strains TA98, TA100, TA102, TA1535 and TA1537 upon addition of HepG2-derived enzyme (S9) mix in liquid incubation assays with identical exposure concentrations . Taken together, our results indicate that FB(1) is clastogenic in human derived cells . This observation supports the assumption that this compound may act as a genotoxic carcinogen in humans. Emerg Infect Dis, 2002 Apr, 8(4), 440 - 3 Salmonella enterica serotype Enteritidis phage type 4b outbreak associated with bean sprouts; van Duynhoven YT et al.; In November 2000 in the Netherlands, an outbreak of Salmonella enterica serotype Enteritidis phage type 4b was investigated . Eating bean sprouts was the only exposure associated with S . Enteritidis pt 4b infection (matched odds ratio 13.0, 95% confidence interval 2.0-552.5) . Contaminated seeds were the most likely cause of contamination of the sprouts . The sprout grower applied a concentration of hypochlorite solution that was too low for seed disinfection. Emerg Infect Dis, 2002 Apr, 8(4), 434 - 6 Multiply resistant (MR) Salmonella enterica serotype Typhimurium DT 12 and DT 120: a case of MR DT 104 in disguise? Lawson AJ, Dassama MU, Ward LR, Threlfall EJ. Multiresistant Salmonella enterica serotype Typhimurium definitive phage type (DT) 12 and DT 120 are more closely related to DT 104 than to non-multiresistant strains of their respective phage types . Multiresistant DT 12 and DT 120 appear to have arisen due to changes in phage susceptibility of DT 104 rather than horizontal transfer of resistance genes. Emerg Infect Dis, 2002 Apr, 8(4), 430 - 3 Salmonella enterica serotype Typhimurium DT 104 antibiotic resistance genomic island I in serotype paratyphi B; Meunier D et al.; We have identified Salmonella genomic island I (SGI1) in an isolate of Salmonella enterica serotype Paratyphi B . This antibiotic-resistance gene cluster, which confers multidrug resistance, has been previously identified in S . enterica serotype Typhimurium phage types DT 104 and DT 120 and in S . enterica serotype Agona. Emerg Infect Dis, 2002 Apr, 8(4), 387 - 91 Salmonella enterica serotype Typhimurium DT104 isolated from humans, United States, 1985, 1990, and 1995; Ribot EM et al.; First isolated from an ill person in 1985, multidrug-resistant Salmonella enterica serotype Typhimurium DT104 emerged in the mid-1990s as a strain of Salmonella frequently isolated from humans in the United States . We compared the integron content, plasmid profile, and XbaI pulsed-field gel electrophoresis (PFGE) patterns of multidrug-resistant S . Typhimurium DT104 (MR-DT104) isolated from humans in the United States in 1985, 1990, and 1995 . All isolates contained a 60-mDa plasmid and had indistinguishable PFGE and integron profiles, supporting the idea of a clonal relationship between recent and historical isolates . The data suggest that the widespread emergence of MR-DT104 in humans and animals in the 1990s may have been due to the dissemination of a strain already present in the United States rather than the introduction of a new strain. Int J Environ Health Res, 2002 Mar, 12(1), 17 - 23 Health effect of human wastes use in agriculture in El Azzouzia (the wastewater spreading area of Marrakesh city, Morocco); Melloul A et al.; The use of wastewater and excreta in agriculture constitutes an important source of spread Salmonella strains and protozoan infections into the environment . This practice has been used in El Azzouzia (the wastewater-spreading area of Marrakesh city, Morocco) for several years . The available circumstantial evidence gained from epidemiological and microbiological investigations suggests that the use of untreated wastewater causes an excess of protozoan infections among children living in El Azzouzia (72%) compared with those from a control area (45%) . The pathogenic protozoan infections observed were giardiasis (39%) and amoebiasis (28%) . For Salmonella infection, 21.34% of the exposed children were infected, while this rate did not exceed 1.14% in the control group . The serogroups B and C were the most commonly isolated . The sewage farming children are therefore more exposed to detectable risk from pathogenic micro-organisms than the control children. Pulm Pharmacol Ther, 2002, 15(1), 7 - 15 Modulation of TNF and GM-CSF release from dispersed human nasal polyp cells and human whole blood by inhibitors of different PDE isoenzymes and glucocorticoids; Marx D et al.; The aim of this study was to investigate the role of the inhibitors of different PDE isoenzymes (PDE 1-5) on the production of two pro-inflammatory cytokines - tumor necrosis factor alpha (TNF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) . Two in vitro models were used to compare the antiinflammatory properties of PDE inhibitors with that of glucocorticoids . The effect on TNF release from diluted human blood following lipopolysaccharide (LPS from Salmonella abortus equi) stimulation as well as the GM-CSF and TNF release from human nasal polyp cells following allergic stimulation were investigated . Both models proofed to be well suited for the characterisation of the antiinflammatory properties of new chemical entities.In diluted human blood and dispersed human nasal polyp cells the induced TNF release was most potently suppressed by selective PDE4 inhibitors . Amrinone and milrinone, selective PDE3 inhibitors, suppressed TNF secretion to a lesser extent . The effects of theophylline (unspecific PDE inhibitor), vinpocetine (PDE1 inhibitor), EHNA (PDE2 inhibitor) and the PDE5 inhibitors zaprinast and E 4021 were weak . In human blood, the tested glucocorticoids beclomethasone, dexamethasone and fluticasone inhibited the LPS induced TNF release potently in a concentration dependent manner, whereas in dispersed human nasal polyp cells, the effect of the glucocorticoids on allergically induced TNF release, with the exception of dexamethasone, was much less pronounced . Glucocorticoids were the most potent inhibitors of GM-CSF release and the effect correlates well with the affinity to the glucocorticoid receptor . The selective PDE 4 inhibitors, and to a certain extent the PDE3 inhibitors amrinone and milrinone, reduced the GM-CSF release in a concentration dependent manner . In all investigations selective PDE4 inhibitors reduced TNF release to a much higher degree (4-10 fold) than GM-CSF release . Indian J Med Res, 2001 May, 113, 175 - 80 Changing pattern of biotypes, phage types & drug resistance of Salmonella typhi in Ludhiana during 1980-1999; Kumar R et al.; BACKGROUND & OBJECTIVES: Ludhiana, an industrial city of Punjab, has a large floating population where typhoid has become endemic . A retrospective study was carried out over a period of 20 years (1980-1999) at Ludhiana on the biotyping, phage typing and drug resistance pattern of Salmonella typhi . METHODS: Of a total of 1697 S . typhi isolates obtained, phage typing and biotyping were done of only 1243 isolates . Antimicrobial susceptibility pattern of these isolates was also studied . RESULTS: Of the 1243 S . typhi isolates, 963 (77.5%) and 280 (22.5%) were of biotype I and biotype II respectively . Twenty four different S . typhi phage types were prevalent in Ludhiana in the past two decades . Between 1980 and 1989, more prevalent phage types were phage type A (35%), O (17.6%) and E1 (15.1%) . During 1990-1999, there was a considerable increase in the incidence of phage type E1 (48.1%) . The cumulative analysis of past two decades revealed that the incidence of phage type E1 (38.8%) was most predominant . In the past one decade (1990-1999), 412 S . typhi isolates of 13 different phage types exhibited multidrug resistance (MDR) pattern ACCoT (resistant to ampicillin, chloramphenicol, co-trimoxazole and tetracycline) . High chloramphenicol resistance (74.7%) and MDR pattern ACCoT (68.2%) was shown by phage type E1 of S . typhi . INTERPRETATION & CONCLUSION: An association was observed between drug resistance and phage type pattern of S . typhi as 70 per cent isolates of S . typhi phage types E1 and O exhibited ACCoT multidrug resistant pattern . Reemergence of chloramphenicol susceptibility in the last decade emphasizes the need for regular antimicrobial surveillance to minimize the misuse of these drugs. Mol Microbiol, 2002 Apr, 44(1), 107 - 18 A two-component regulator induces the transmission phenotype of stationary-phase Legionella pneumophila; Hammer BK et al.; Pathogenic Legionella pneumophila evolved as a parasite of aquatic amoebae . To persist in the environment, the microbe must be proficient at both replication and transmission . In laboratory cultures, as nutrients become scarce a stringent response-like pathway coordinates exit from the exponential growth phase with induction of traits correlated with virulence, including motility . A screen for mutants that express the flagellin gene poorly identified five activators of virulence: LetA/LetS, a two-component regulator homologous to GacA/GacS of Pseudomonas and SirA/BarA of Salmonella; the stationary-phase sigma factor RpoS; the flagellar sigma factor FliA; and a new locus, letE . Unlike wild type, post-exponential-phase letA and letS mutants were not motile, cytotoxic, sodium sensitive or proficient at infecting macrophages . L . pneumophila also required fliA to become motile, cytotoxic and to infect macrophages efficiently and letE to express sodium sensitivity and maximal motility and cytotoxicity . When induced to express RelA, all of the strains exited the exponential phase, but only wild type converted to the fully virulent form . In contrast, intracellular replication was independent of letA, letS, letE or fliA . Together, the data indicate that, as the nutrient supply wanes, ppGpp triggers a regulatory cascade mediated by LetA/ LetS, RpoS, FliA and letE that coordinates differentiation of replicating L . pneumophila to a transmissible form. J Appl Microbiol, 2002, 92(4), 668 - 74 Combined effects of chemical, heat and ultrasound treatments to kill Salmonella and Escherichia coli O157:H7 on alfalfa seeds; Scouten AJ et al.; AIMS: To determine the effectiveness of combined treatments with chemicals, heat and ultrasound in killing or removing Salmonella and Escherichia coli O157:H7 on alfalfa seeds intended for sprout production . METHODS AND RESULTS: Alfalfa seeds inoculated with Salmonella or E . coli O157:H7 were treated with ultrasound (38.5-40.5 kHz) in solutions containing 1% Ca(OH)(2), 1% Tween 80, 1% Ca(OH)(2) plus 1% Tween 80, 160 microg ml(-1) Tsunami 200 and 0.5% Fit at 23 and 55 degrees C for 2 and 5 min . Highest reductions were in chemical solutions at 55 degrees C, but seed viability was also reduced compared with treatment at 23 degrees C . Inactivation of Salmonella and E . coli O157:H7 was generally enhanced by simultaneous treatments with ultrasound, chemicals and heat . CONCLUSIONS: Ultrasound treatment, in combination with chemicals and heat, had a modest enhancing effect on the effectiveness of chemicals in killing or removing pathogens on alfalfa seeds . Overall, treatment with 1% Ca(OH)(2) was most effective in killing Salmonella and E . coli O157:H7 . SIGNIFICANCE AND IMPACT OF THE STUDY: The use of 1% Ca(OH)(2) instead of 20,000 microg ml(-1) chlorine, which is currently recommended as a sanitizer for seeds intended for sprout production in the US, should be considered . Ultrasound treatment of alfalfa seeds containing Salmonella or E . coli O157:H7, in combination with chemical treatment, contributes to achieving greater reductions in populations of these pathogens, thereby reducing the risk of contamination and the presence of pathogens in sprouts produced from these seeds. Toxic Rep Ser, 1998 Mar, 43, 1 - F20 NTP Comparative Toxicity Studies of o-, m-, and p-Chloroanilines (CAS Nos . 95-51-2; 108-42-9; and 106-47-8) Administered by Gavage to F344/N Rats and B6C3F1 Mice; Extended-spectrum beta-lactamases: the European experience; Infectious Disease Division, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213-2582, USA . patersondl@hotmail.com Extended-spectrum beta-lactamases mediate resistance to cephalosporin antibiotics and were first discovered in Europe in the early 1980s . They have become a widespread problem, particularly in Klebsiella pneumoniae, but increasingly in non-typhoid Salmonella species . Traditionally, extended-spectrum beta-lactamases have been derivatives of TEM and SHV parent enzymes . The last year, however, has seen an explosion of developments in extended-spectrum beta-lactamases of non-TEM, non-SHV lineage in Europe . The CTX-M type extended-spectrum beta-lactamases have become particularly widespread . At the same time, European clinical microbiology laboratories have become more aware of the pressing need for detection methods given increasing awareness of the lack of reliability of cephalosporins in the treatment of extended-spectrum beta-lactamase producers. Curr Opin Infect Dis, 2001 Jun, 14(3), 265 - 71 The protective role of interleukin-18 in Salmonella infection; Pascual DW; Since its derivation, much has been learned about the proinflammatory inducing cytokine interleukin-18, and its role in resolving infectious diseases . Studies to date that examined interleukin-18 have shown that endogenously induced interleukin-18 plays an important protective role in some viral and bacterial infections . However, interleukin-18 has a limited role in protective immunity to Salmonella infections, and is secondary to