Vet Microbiol, 2002 Oct 2, 89(1), 53 - 60 The prevalence and PCR detection of Salmonella contamination in raw poultry; Whyte P et al.; Contaminated poultry meat has been identified as one of the principal foodborne sources of Salmonella . The development of rapid detection assays for Salmonella would enable official agencies and food industries to identify contaminated foodstuffs in a more timely manner . In addition, these diagnostic tools could allow more 'real time' decisions to be made regarding end product acceptability . In this study, a survey was carried out to determine the prevalence of Salmonella in raw broiler carcasses . A total of 198 neck skin samples were obtained from within 40 flocks at a commercial broiler slaughtering facility . The presence of Salmonella was assessed by traditional culture methods and by a Salmonella-specific polymerase chain reaction (PCR) test . Salmonella was recovered from 32 (16%) of all samples using traditional culture methods . In contrast, the PCR assay proved to be more sensitive and detected Salmonella DNA in 38 (19%) of the samples tested . The pathogen was detected in 45 (23%) of the 198 samples when culture and PCR results were combined . The sensitivity of the PCR test was also greater than culture when detecting Salmonella from within flocks (53% of flocks by PCR, 30% of flocks by culture) . The combination of both tests revealed that 55% of the flocks were contaminated with Salmonella . The PCR assay proved to be a highly specific and sensitive method for detecting Salmonella and the incorporation of a routine PCR test in conjunction with standard culture could be effective in providing a more accurate profile of the prevalence of this pathogen in broiler carcasses. Harefuah, 2002 Aug, 141(8), 685 - 8, 763 {Salmonella virchow sacroiliitis and bacteremia in a child}; Genizi J et al.; A 2.5 years old girl was admitted because of high fever and limping that appeared two days after she had trauma to her right leg . Bone scan demonstrated increased uptake in the right sacroiliac joint, and CT demonstrated right sacroiliitis . Salmonella vircow was isolated from the blood culture . The patient recovered after a five weeks course of intravenous antibiotics . Salmonella sacroiliitis in children is rare, and only seven cases have been reported in the English literature in the last 40 years . We reviewed the literature dealing with pathophysiology diagnosis therapy and outcome of this infection. Environ Microbiol, 2002 Sep, 4(9), 538 - 45 Mitigation of avian reproductive tract function by Salmonella enteritidis producing high-molecular-mass lipopolysaccharide; Parker CT et al.; Hens were infected with a wild-type Salmonella enteritidis and its wzz mutant, which lacked the ability to make high-molecular-mass lipopolysaccharide (LPS), in six experiments paired by dosage and route of exposure . Involution of the reproductive tract occurred in 86% of hens that were injected subcutaneously with 108 cfu of the wild-type strain, but none did so when injected with the wzz mutant . In spite of the lack of a specific effect on the reproductive tract, infection of hens with the mutant produced more contaminated eggs and heterophilic granulomas in developing ova (yolks) than wild type; thus, overall, the mutant appeared to be more virulent except after intravenous injection . The mutant also decreased shell quality more often than wild type, regardless of dosage or route of infection . These results suggest that egg-contaminating Salmonella enteritidis that produces high-molecular-mass LPS mitigates signs of illness in poultry by altering the response of the avian reproductive tract to infection, but without altering the incidence of egg contamination following bacteraemia . Further research is warranted to determine whether analyses of shell quality might aid in identification of flocks at risk of producing contaminated eggs. Plasmid, 2002 Jul, 48(1), 59 - 63 Sequence analysis and characterization of plasmid pSFD10 from Salmonella choleraesuis; Liu M et al.; The nucleotide sequence of a small plasmid, designated pSFD10, is isolated from the vaccine strain Salmonella choleraesuis C500 in China, has been determined . This plasmid is 4091 bp long with a total G+C content of 51.4%, which is in the range of Salmonella genomic DNA . Analysis of the complete nucleotide sequence reveals that pSFD10 has a high degree of similarity to ColE1-type plasmid, having the possible cer and rom genes, and a putative mobilization origin of ColE1-type . Plasmid pSFD10 possesses six main open reading frames (ORFs), five of which have a very high degree of amino acid identity to ColE1-type plasmid gene products involved in mobilization and copy number control . The other ORF (ORF6) encodes a putative protein, which has 49% homology to the invasion plasmid antigen J protein (IpaJ) secreted by the type III secretion apparatus of Shigella flexneri . In addition, pSFD10 belongs to a different incompatibility group than ColE1-type and pMB1-type to which it is related . Plasmid pSFD10 can be mobilized by the plasmid RP4 in E . coli. Rev Inst Med Trop Sao Paulo, 2002 Jul-Aug, 44(4), 235 - 7 Isolation of Salmonella enterica and serologic reactivity to Leptospira interrogans in opossums (Didelphis virginiana) from Yucatán, México; Ruiz-Pina HA et al.; The presence of Salmonella enterica and serologic evidence of infection by Leptospira interrogans, were detected in the opossum Didelphis virginiana in a semi-urban locality of the Yucatan State, Mexico . Ninety-one opossums were captured during the period April 1996 and May 1998 . From a total of 17 feces samples, four Salmonella enterica subsp . enterica serotypes (Sandiego, Newport, Anatum, and Minnesota), and one Salmonella enterica subsp . arizonae serovar O44:Z4,Z23:- were isolated . Some opossums presented mixed infections . From 81 sera samples, four (4.9%) were positive to antibodies to Leptospira serovars pomona and wolfii . Both animals infected with Salmonella enterica and those serologically positive to Leptospira interrogans were captured in peridomestic habitat . Opossums infected with Salmonella enterica, were captured in dry season, and those seropositive to Leptospira interrogans during the rainy season . The implications of infection and reactivity of these zoonotic pathogens in D . virginiana in the Yucatan state are briefly discussed. J Pediatr, 2002 Sep, 141(3), 381 - 7 Infection due to extended-spectrum beta-lactamase-producing Salmonella enterica subsp . enterica serotype infantis in a neonatal unit; Pessoa-Silva CL et al.; OBJECTIVE: To describe the investigation and control of an outbreak of extended-spectrum beta-lactamase producing Salmonella enterica subsp . enterica serotype Infantis in a neonatal unit in Brazil . METHODS: A case-control study for risk factors for Salmonella Infantis systemic infection, environmental cultures, and evaluation of staffing and overcrowding and an assessment of infection control practices were performed . RESULTS: During July 1998 to June 1999, 140 Salmonella Infantis culture-positive patients were identified in the neonatal unit . Presence of a peripheral intravascular catheter was identified as an independent risk factor (odds ratio = 4.98; 95% CI = 1.59-19.31; P =.01) and each 250-g increase in birth weight as a protective factor (odds ratio = 0.76; 95% CI = 0.57-0.95; P =.03) . Hospital stay was significantly longer and costs higher in case patients than in control patients . Salmonella Infantis was isolated from multiple environmental sources . Neonatal unit personnel were observed to make several breaks in infection control practices . The unit was understaffed and overcrowded . Prompt case identification, cohorting of patients, enhanced staff hand hygiene, and environmental cleaning terminated the outbreak . CONCLUSIONS: Inadequate infection control practices, nursery overcrowding, and understaffing can have an adverse effect on patient morbidity, mortality rates, and hospital cost. J Bacteriol, 2002 Oct, 184(19), 5468 - 78 Mutational analysis of the Escherichia coli PhoQ sensor kinase: differences with the Salmonella enterica serovar Typhimurium PhoQ protein and in the mechanism of Mg2+ and Ca2+ sensing; Regelmann AG et al.; The PhoP-PhoQ two-component system plays a role in Mg2+ homeostasis and/or the virulence properties of a number of bacterial species . A Salmonella enterica serovar Typhimurium PhoQ sensor kinase mutant, in which the threonine at residue 48 in the periplasmic sensor domain is changed to an isoleucine, was shown previously to result in elevated expression of PhoP-activated genes and to affect mouse virulence, epithelial cell invasion, and sensitivity to macrophage killing . We characterized a complete set of proteins having amino acid substitutions at position 48 in the closely related Escherichia coli PhoQ protein . Numerous mutant proteins having amino acid substitutions with side chains of various sizes and characters displayed signaling phenotypes similar to that of the wild-type protein, indicating that interactions mediated by the wild-type threonine side chain are not required for normal protein function . Changes to amino acids with aromatic side chains had little impact on signaling in response to extracellular Mg2+ but resulted in reduced sensitivity to extracellular Ca2+, suggesting that the mechanisms of signal transduction in response to these two divalent cations are different . Surprisingly, the Ile48 protein displayed a defective phenotype rather than the hyperactive phenotype seen with the S . enterica serovar Typhimurium protein . We also describe a mutant PhoQ protein lacking the extracellular sensor domain with a defect in the ability to activate PhoP . The defect does not appear to be due to reduced autokinase activity but rather appears to be due to an effect on the stability of the aspartyl-phosphate bond of phospho-PhoP. J Bacteriol, 2002 Oct, 184(19), 5307 - 16 Adaptation of sucrose metabolism in the Escherichia coli wild-type strain EC3132; Jahreis K et al.; Although Escherichia coli strain EC3132 possesses a chromosomally encoded sucrose metabolic pathway, its growth on low sucrose concentrations (5 mM) is unusually slow, with a doubling time of 20 h . In this report we describe the subcloning and further characterization of the corresponding csc genes and adjacent genes . The csc regulon comprises three genes for a sucrose permease, a fructokinase, and a sucrose hydrolase (genes cscB, cscK, and cscA, respectively) . The genes are arranged in two operons and are negatively controlled at the transcriptional level by the repressor CscR . Furthermore, csc gene expression was found to be cyclic AMP-CrpA dependent . A comparison of the genomic sequences of the E . coli strains EC3132, K-12, and O157:H7 in addition to Salmonella enterica serovar Typhimurium LT2 revealed that the csc genes are located in a hot spot region for chromosomal rearrangements in enteric bacteria . The comparison further indicated that the csc genes might have been transferred relatively recently to the E . coli wild-type EC3132 at around the time when the different strains of the enteric bacteria diverged . We found evidence that a mobile genetic element, which used the gene argW for site-specific integration into the chromosome, was probably involved in this horizontal gene transfer and that the csc genes are still in the process of optimal adaptation to the new host . Selection for such adaptational mutants growing faster on low sucrose concentrations gave three different classes of mutants . One class comprised cscR(Con) mutations that expressed all csc genes constitutively . The second class constituted a cscKo operator mutation, which became inducible for csc gene expression at low sucrose concentrations . The third class was found to be a mutation in the sucrose permease that caused an increase in transport activity. J Bacteriol, 2002 Oct, 184(19), 5234 - 9 Identification of GtgE, a novel virulence factor encoded on the Gifsy-2 bacteriophage of Salmonella enterica serovar Typhimurium; Ho TD et al.; The Gifsy-2 temperate bacteriophage of Salmonella enterica serovar Typhimurium contributes significantly to the pathogenicity of strains that carry it as a prophage . Previous studies have shown that Gifsy-2 encodes SodCI, a periplasmic Cu/Zn superoxide dismutase, and at least one additional virulence factor . Gifsy-2 encodes a Salmonella pathogenicity island 2 type III secreted effector protein . Sequence analysis of the Gifsy-2 genome also identifies several open reading frames with homology to those of known virulence genes . However, we found that null mutations in these genes did not individually have a significant effect on the ability of S . enterica serovar Typhimurium to establish a systemic infection in mice . Using deletion analysis, we have identified a gene, gtgE, which is necessary for the full virulence of S . enterica serovar Typhimurium Gifsy-2 lysogens . Together, GtgE and SodCI account for the contribution of Gifsy-2 to S . enterica serovar Typhimurium virulence in the murine model. J Bacteriol, 2002 Oct, 184(19), 5214 - 22 Role of OxyR as a peroxide-sensing positive regulator in Streptomyces coelicolor A3(2); Hahn JS et al.; Genes encoding a homolog of Escherichia coli OxyR (oxyR) and an alkyl hydroperoxide reductase system (ahpC and ahpD) have been isolated from Streptomyces coelicolor A3(2) . The ahpC and ahpD genes constitute an operon transcribed divergently from the oxyR gene . Expression of both ahpCD and oxyR genes was maximal at early exponential phase and decreased rapidly as cells entered mid-exponential phase . Overproduction of OxyR in Streptomyces lividans conferred resistance against cumene hydroperoxide and H2O2 . The oxyR mutant produced fewer ahpCD and oxyR transcripts than the wild type, suggesting that OxyR acts as a positive regulator for their expression . Both oxyR and ahpCD transcripts increased more than fivefold within 10 min of H2O2 treatment and decreased to the normal level in 50 min, with kinetics similar to those of the CatR-mediated induction of the catalase A gene (catA) by H2O2 . The oxyR mutant failed to induce oxyR and ahpCD genes in response to H2O2, indicating that OxyR is the modulator for the H2O2-dependent induction of these genes . Purified OxyR protein bound specifically to the intergenic region between ahpC and oxyR, suggesting its direct role in regulating these genes . These results demonstrate that in S . coelicolor OxyR mediates H2O2 induction of its own gene and genes for alkyl hydroperoxide reductase system, but not the catalase gene (catA), unlike in Escherichia coli and Salmonella enterica serovar Typhimurium. J Mol Biol, 2002 Sep 13, 322(2), 281 - 90 Structural properties of FliH, an ATPase regulatory component of the Salmonella type III flagellar export apparatus; Minamino T et al.; FliH is a regulatory component for FliI, the ATPase that is responsible for driving flagellar protein export in Salmonella . FliH consists of 235 amino acid residues, has a quite elongated shape, exists as a homodimer and together with FliI forms a heterotrimer . Here, we have investigated the structural properties of the FliH homodimer in further detail . Like intact His-tagged FliH homodimer, fragment His-FliH(N2) (consisting of the first 102 amino acid residues of FliH), exhibited anomalous elution behavior in gel filtration chromatography; the same was true of His-FliH(C1) (consisting of amino acid residues 119-235), but to a much lesser degree . Thus the elongated shape of FliH appears to derive primarily from its N-terminal region . A deletion version of N-His-FliH, lacking amino acid residues 101-140, does not dimerize and so we were able to establish the gel filtration properties of an almost full-size monomeric form; it also exhibited anomalous elution behavior . We performed trypsin proteolysis of the FliH homodimer and subjected the cleavage products to gel filtration chromatography . FliH was degraded by trypsin and a contaminating protease into two stable fragments: FliH(Prt1) (missing both the first ten and the last 12 amino acid residues), and FliH(Prt2) (missing both the first ten and the last 63 amino acid residues); however, substantial amounts remained undigested even after 24 hours . Under native conditions, both FliH(Prt1) and FliH(Prt2) co-eluted with undigested His-FliH from the gel filtration column, indicating that the fragments exist as a hybrid dimer with intact FliH . These results suggest that the two subunits within the dimer differ in their proteolytic susceptibility . No heterotrimer was observed by gel filtration chromatography when His-FliI was mixed with either His-FliH/FliH(Prt1) or His-FliH/FliH(Prt2) hybrid dimers . A hybrid dimer of FliH and His-FliHDelta1 (lacking the first ten amino acid residues) retained the ability to form a complex with His-FliI . In contrast, hybrid dimers consisting of FliH and either His-FliH(W223ochre) or His-FliH(V172ochre) failed to complex to His-FliI, demonstrating that the C-terminal region of both FliH monomers within the FliH dimer are required for heterotrimer formation. Trends Microbiol, 2002 Sep, 10(9), 391 - 2 Salmonella selectively stops traffic; Fang F et al.; The intracellular pathogen Salmonella replicates in infected host cells within a specialized vacuole referred to as the Salmonella-containing vacuole (SCV) . Effector molecules encoded by the Salmonella pathogenicity island 2 (SPI-2) type III secretion system (TTSS) are essential for Salmonella to survive in the intracellular environment . It was previously shown that SPI-2 allows Salmonella to inhibit the recruitment of NADPH phagocyte oxidase-containing vesicles to SCVs . New research has now revealed that SPI-2 effectors also interfere with the colocalization of inducible nitric oxide synthase (iNOS) to SCVs, thus protecting the pathogen from the antimicrobial actions of reactive nitrogen species. Salud Publica Mex, 2002 Jul-Aug, 44(4), 297 - 302 {Outbreak caused by Escherichia coli in Chalco, Mexico}; Cortes-Ortiz IA et al.; OBJECTIVE: To identify the etiologic agent responsible for a disease outbreak following an overflow of sewage water in Valle de Chalco, Mexico . MATERIAL AND METHODS: A retrospective cross-sectional study was carried out . Rectal samples were collected from the population of Chalco valley, who suffered from diarrhea and vomiting during a natural disaster that took place on May 31, 2000 . The Instituto de Diagnostico y Referencia Epidemiologicos (Epidemic Reference and Diagnosis Institute, InDRE, Ministry of Health), received 1521 rectal swab samples from diarrhea cases, to test for E . coli strains . Statistical analysis was performed to find a difference of proportions between cases and non-cases (chi-squared test) . ETEC, EIEC, EPEC and EHEC pathogenic E . coli groups were hybridized by colony blot . RESULTS: Strains isolated were ETEC (62.2%), EIEC (0.84%), EPEC (0.84%), and EHEC non-O157:H7 (0.08%); there was no hybridization in 36.02% of E . coli strains . Other isolated microorganisms were Salmonella spp (0.45%) and Shigella spp (0.06%) . CONCLUSIONS: Enterotoxigenic E . coli was the most likely etiologic agent . Sanitary control strategies should be targeted to preventing outbreaks caused by this pathogenic agent . The English version of this paper is available at: http://www.insp.mx/salud/index.html. J Egypt Soc Parasitol, 2002 Aug, 32(2), 355 - 60 Delayed Salmonella bacteriuria in a patient infected with Schistosoma haematobium; Bouree P et al.; The authors report a case of Schistosoma haematobium infection with delayed occurrence of Salmonella bacteriuria following treatment of schistosomiasis . Standard models of interaction between these two pathogens may not be fully satisfactory in such a case of co-infection . The role played by a decreased host immune response following schistosomiasis may thus be highlighted to explain a delayed or prolonged infection with Salmonella. Microbiology, 2002 Sep, 148(Pt 9), 2727 - 33 ClpP is involved in the stress response and degradation of misfolded proteins in Salmonella enterica serovar Typhimurium; Thomsen LE et al.; Components of the ATP-dependent Clp protease complex are found in a wide range of prokaryotic cells and they are often expressed as part of the cellular stress response . To investigate the physiological role of the proteolytic subunit, ClpP, in Salmonella enterica serovar Typhimurium (S . typhimurium) an in-frame deletion of the clpP gene was constructed . Growth experiments revealed that clpP is important for the ability of S . typhimurium to grow under various stressful conditions, such as low pH, elevated temperature and high salt concentrations . Since the stationary-phase sigma factor, RpoS, is a target of the Clp proteolytic complex, the effect of the clpP deletion in the absence of RpoS was examined; it was observed that growth of the S . typhimurium clpP mutant is affected in both an RpoS-dependent and an RpoS-independent manner . Analysis of the degradation of abnormal puromycyl-containing polypeptides showed that ClpP participates in the proteolysis of such proteins in S . typhimurium . These findings prompted an investigation of the growth of an Escherichia coli clpP mutant under various stress conditions . The growth of this E . coli mutant was affected by heat, salt and low pH, although not to the same extent as observed for the S . typhimurium clpP mutant . The results of this study indicate that the S . typhimurium clpP mutant is generally more sensitive to environmental stress than the E . coli clpP mutant and it is proposed that this is due to a reduced ability to degrade misfolded proteins generated under these conditions. Microbiology, 2002 Sep, 148(Pt 9), 2717 - 26 Active but nonculturable cells of Salmonella enterica serovar Typhimurium do not infect or colonize mice; Smith RJ et al.; The possibility that nonculturable cells of a normally culturable bacterial pathogen may constitute a source or reservoir for infective disease was investigated . In multiple experiments and with careful attention to the statistical limitations of the assays used, Salmonella enterica serovar Typhimurium cells rendered nonculturable by carbon and nitrogen stress in the presence of chloramphenicol were administered orally and intraperitoneally to over 300 female BALB/c mice . Neither infection nor colonization was detected in these studies, even when active but nonculturable (ABNC) cells, as defined by the Kogure cell elongation assay, were present in the inoculum . Doses of ABNC cells exceeding the oral and intraperitoneal LD(50) values by 3.5 and 2 orders of magnitude, respectively, were administered . It was concluded that ABNC cells of the salmonella strains used could not be considered potentially infective and that their detection in samples from material being evaluated as a potential source or reservoir of infection by the Kogure test does not specifically represent an infective hazard. Microbiology, 2002 Sep, 148(Pt 9), 2705 - 15 Growth and killing of a Salmonella enterica serovar Typhimurium sifA mutant strain in the cytosol of different host cell lines; Beuzon CR et al.; Intracellular pathogens have developed different mechanisms which enable their survival and replication within the host cells . Some survive and replicate within a membrane-bound vacuole modified by the bacteria to support microbial growth (e.g . Salmonella enterica serovar Typhimurium), whereas others escape from the vacuole into the host cell cytosol, where they proliferate (e.g . Listeria monocytogenes) . In this study a Salmonella strain carrying a mutation in sifA which is released from the vacuole was used to analyse Salmonella survival and replication within the cytosol of several cell lines . It was found that Salmonella replicates within the cytosol of epithelial cells at a higher rate than that achieved when replicating within the vacuole, but is defective for replication in the cytosol of fibroblasts or macrophages . Using an aroC purD double mutant strain which does not replicate within host cells, it was shown that Salmonella encounters a killing activity within the cytosol of macrophages . Furthermore, in vitro experiments using cytosol extracted from either infected or uninfected macrophages suggested that this activity is activated upon Salmonella infection. Vaccine, 2002 Sep 10, 20(27-28), 3239 - 43 The effect of recombinant plasmids on in vivo colonisation of Salmonella enterica serovar Typhimurium strains is not reflected by in vitro cellular invasion assays; Garmory HS et al.; Attenuated strains of Salmonella enterica serovar Typhimurium are used as carriers of heterologous antigens as candidate oral vaccines and, more recently, as carriers of DNA vaccines . In this study, recombinant Salmonella strains that were altered in their ability to colonise murine tissues in vivo when compared to parent strains were not, however, equally altered in their ability to invade murine cells in vitro . These results suggest that in vitro invasion studies may not be a representative model for colonisation of tissues in vivo, and that in vitro studies should ideally be used in conjunction with in vivo studies for the assessment of potential Salmonella vaccines. Ren Fail, 2002 Jul, 24(4), 535 - 8 Diarrhea associated acute renal failure in a patient with Salmonella enteritidis sepsis; Lin WR et al.; Salmonella enteritidis infection occurs primarily in animals and often results in self-limited gastroenteritis in accidental cross contamination in human . However, the acute renal failure could be a rare but serious complication of the S . enteritidis infection . We report one case of acute renal failure from severe dehydration caused by S . enteritidis food poisoning . The acute renal failure completely recovered after hydration and antibiotic treatment. Epidemiol Infect, 2002 Aug, 129(1), 35 - 9 An outbreak of Salmonella enteritidis phage type 34a infection in primary school children: the use of visual aids and food preferences to overcome recall bias in a case control study; Linnane E et al.; Outbreaks of infectious intestinal disease are common in schools . Case control studies are useful in the investigation of infectious disease outbreaks but the time interval between illness and investigation can lead to recall bias, particularly in young children . We describe an outbreak of Salmonella enteritidis phage type 34a infection involving 54 clinical cases in two adjacent schools, and a novel approach to overcome recall bias . The likely dates of infection were identified from the epidemic curve . We created a visual display of the menu from those days and asked 9 cases and 18 matched controls to identify their food preferences from this display . Preference for chocolate mouse was significantly associated with illness (P = 0.006) . The results of the case control study agreed with the findings of the environmental investigation . We believe our approach could be used in other circumstances, where subjects are young children or recall bias is a concern. Epidemiol Infect, 2002 Aug, 129(1), 29 - 34 Decline in epidemic of multidrug resistant Salmonella typhi is not associated with increased incidence of antibiotic-susceptible strain in Bangladesh; Rahman M et al.; Since 1987, multidrug resistant (MDR) strains of Salmonella Typhi, resistant simultaneously to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole, have caused epidemics of severe typhoid fever in Asia and Africa . A retrospective analysis of blood culture results (1989-96) in a Diarrhoea Treatment Centre in Dhaka, Bangladesh detected MDR strains in 0.3% (8 of 2793) of samples in 1990 . The isolation rate peaked to 3.2% (240 of 7501) in 1994 (P < 0.01) and decreased to 1.8% (165 of 9348) in 1995 and further to 1.0% (82 of 8587) in 1996 (P < 0.01 compared to 1994) indicating the emergence and decline of MDR typhoid epidemic . Ten of 15 MDR strains tested had a 176 kb conjugative R plasmid that mediates resistance to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole to Escherichia coli K12 . Unlike MDR strains, the isolation rate (approximately 3.3%) of susceptible S . Typhi remained remarkably unchanged during the study . The significant decrease in isolation of MDR strains suggests that cheaper and effective first-line antibiotics may re-emerge as drugs of choice for the treatment of typhoid fever in Bangladesh. Epidemiol Infect, 2002 Aug, 129(1), 19 - 27 Human salmonellosis associated with young poultry from a contaminated hatchery in Michigan and the resulting public health interventions, 1999 and 2000; Wilkins MJ et al.; Although approximately 95% of disease caused by nontyphoidal salmonella is transmitted by foodborne vehicles, four documented salmonella outbreaks in the 1990s have been traced to contact with young poultry . No environmental studies of source hatcheries were completed . This case-control study was performed by comparing culture-confirmed Salmonella Infantis in Michigan residents, identified between May and July 1999, with two age- and neighbourhood-matched controls . Eighty environmental and bird tissue samples were collected from an implicated hatchery; all salmonella isolates underwent pulsed-field gel electrophoresis (PFGE) analysis . The study included 19 case-patients sharing the same PFGE subtype and 37 matched controls . Within 5 days before illness onset, 74% of case-patients resided in households raising young poultry compared with 16% of controls (matched OR 19.5; 95% CI 2.9, 378.1) . Eight hatchery samples yielded Salmonella Infantis with PFGE subtypes matching the patients' isolates . This investigation identified birds from a single hatchery as the source of human illness and confirmed the link by matching PFGE patterns from humans, birds and the hatchery environment . Subsequent public health interventions reduced, but did not eliminate, transmission of poultry-associated salmonellosis . Five additional PFGE-linked cases were identified in Spring 2000, necessitating quarantine of the hatchery for depopulation, cleaning and disinfection. Epidemiol Infect, 2002 Aug, 129(1), 155 - 61 Drug resistances in salmonella isolates from animal foods, italy 1998-2000; Mammina C et al.; We investigated the distribution of serotypes and patterns of drug resistance of 206 strains of salmonella isolated in southern Italy in the years 1998-2000 from raw food of animal origin, faeces of food animals and animal feed . To improve knowledge of mobile genetic elements carrying the resistance genes, some molecular features were also investigated within isolates resistant to three or more antibiotics . A high proportion of isolates, 52.2% and 37.7%, respectively, belonging to both Typhimurium and other serotypes of animal origin, proved to be multidrug resistant . The DT104 complex specific multidrug pattern of resistance was quite infrequent among isolates other than Typhimurium, but resistances to nalidixic acid and kanamycin were more frequent within these last ones (36.9% vs . 11.4% and 56.5% vs . 2.2%, respectively) . Class I integrons were detected in isolates of Typhimurium and seven different serotypes . The relevance of food animal environment as a drug resistance reservoir and animal food as a potential resistance gene vehicle between the farm and human ecological niches is confirmed by our findings. Epidemiol Infect, 2002 Aug, 129(1), 1 - 8 Salmonella surveillance: a global survey of public health serotyping; Herikstad H et al.; To better understand the global epidemiology of salmonellosis and the national surveillance programmes used for salmonella infections in humans, we conducted a global survey of the 191 WHO Member States . We gathered information on the total number of salmonella isolates serotyped, and the 15 most commonly isolated serotypes from humans in 1990 and 1995 . Of the 104 countries that responded, 76 (73.1%) conducted public health surveillance for salmonella and 69 of these (90.8%) conducted serotyping as part of the surveillance . Fifty-nine countries (56.7% of those responding) provided information about the most commonly isolated serotypes in 1995 . Three serotypes, Enteritidis, Typhimurium and Typhi accounted for 76.1% of all isolates reported in 1995 . One of these three was the most common serotype identified in 93.2% of countries reporting data for that year . In 1995, Enteritidis was the most frequently isolated serotype in 35 countries, followed by Typhi (12 countries) and Typhimurium (8 countries) . The global pandemic of Salmonella Enteritidis continued to expand . The mean national proportion of all salmonella isolates that were Enteritidis increased globally from 25.6% in 1990 to 36.3% in 1995 . Serotyping is a frequently used component of a public health response to the global challenge of salmonellosis . Support for serotyping as part of national salmonella surveillance, and for rapid international communication of the results via a new WHO electronic website will help target future prevention strategies. Poult Sci, 2002 Aug, 81(8), 1128 - 31 Detection of experimental Salmonella enteritidis and S . typhimurium infections in laying hens by fluorescence polarization assay for egg yolk antibodies; Gast RK et al.; Identifying infected laying flocks is a critical component in efforts to prevent eggborne transmission of Salmonella enteritidis to humans . In the present study, egg yolk samples from experimentally infected chickens were tested for specific antibodies with a very rapid fluorescence polarization assay using tracers prepared from the O-polysaccharides of S . enteritidis and S . typhimurium and a conventional ELISA using an S . enteritidis flagellin antigen . In two trials, groups of specific-pathogen-free laying hens were infected orally with 106 or 10(8) cfu of S . enteritidis (phage type 13a) or with 10(8) cfu of S . typhimurium . Eggs were collected during five weekly postinoculation intervals . Both fluorescence polarization and ELISA detected the majority of hens infected with S . enteritidis at either dose level, although they also frequently cross-reacted with samples from hens infected with S . typhimurium . Fluorescence polarization with an S . typhimurium tracer was likewise able to consistently detect S . typhimurium infection but also tended to cross-react with samples from hens infected with S . enteritidis . Fluorescence polarization appears to offer a simple and rapid alternative to conventional serological methodology, although concerns about specificity may limit the usefulness of antibody testing data. Environ Mol Mutagen, 2002, 40(1), 1 - 17 Genotoxicity of naturally occurring indole compounds: correlation between covalent DNA binding and other genotoxicity tests; Reddy MV et al.; 3-Methylindole (3MI), melatonin (Mel), serotonin (Ser), and tryptamine (Tryp) were evaluated in vitro for their potential to induce DNA adducts, DNA strand breaks, chromosomal aberrations (Abs), inhibition of DNA synthesis, and mutations . All compounds produced DNA adducts in calf thymus DNA in the presence of rat liver S9 . In cultured rat hepatocytes, all produced DNA adducts but none induced DNA strand breaks . In Chinese hamster ovary cells, 3MI and Mel produced DNA adducts, Abs, and inhibition of DNA synthesis with and without S9, except that Mel without S9 did not form adducts . Ser formed DNA adducts, was an equivocal Abs inducer, and suppressed DNA synthesis . Tryp induced neither adducts nor Abs, but did suppress DNA synthesis with S9 . Ser and Tryp were less cytotoxic than 3MI and Mel . Mel, Ser, and Tryp failed to induce mutations in Salmonella and E . coli strains with or without S9 . 3MI and Mel produced DNA adducts but not mutations in Salmonella TA100 with S9 . 3MI and its metabolite indole 3-carbinol also did not induce mutations in a shuttle vector system in human cells . The lack of correlation between DNA adducts and other genotoxicity endpoints for these indole compounds may be due to the higher sensitivity of the (32)P-postlabeling adduct assay or it may indicate that the indole-DNA adducts per se are not mutagenic and are not able to induce strand breaks or alkali-labile lesions . The indole-induced Abs may result from cytotoxicity and suppression of DNA synthesis with minimal if any contribution from DNA adducts . Toxic Rep Ser, 1992 Mar, 10, 1 - B7 NTP technical report on the toxicity studies of Ethylbenzene (Cas No . 100-41-4) in F344/N Rats and B6C3F1 Mice (Inhalation Studies); Chan P; Ethylbenzene is commonly used as a solvent and chemical intermediate and as an additive in some motor fuel formulations . Inhalation toxicology studies of ethylbenzene (99% pure) were conducted by exposing groups of F344/N rats and B6C3F1 mice of each sex to ethylbenzene vapor at chamber concentrations of 0, 100, 250, 500, 750, or 1000 ppm, 6 hours per day, 5 days per week for 13 weeks . No rats or mice died during the 13-week exposure . Body weight gains were slightly lower in the high dose groups of male and female rats, but the differences were not statistically significant . Absolute and relative kidney, liver, and lung weights were increased in the exposed rats, while weight increases occurred only in the livers of exposed mice . Chemically related histopathologic changes were not observed in any tissues of rats or mice . No changes were observed in the evaluation of sperm or vaginal cytology in rats or mice . Ethylbenzene was not mutagenic in Salmonella and did not induce chromosomal aberrations or sister chromatid exchanges in Chinese hamster ovary (CHO) cells in vitro, though it did induce trifluorothymidine resistance in mouse lymphoma cells at the highest concentration tested . Micronuclei assays in peripheral blood of mice were negative . Thus, there appears to be only minimal evidence of toxicity in F344/N rats and B6C3F1 mice exposed to ethylbenzene by inhalation at concentrations as high as to 1000 ppm for 13 weeks . Synonyms: EB, ethyl benzene, ethylbenzol, phenylethane . (NOTE: These studies were supported in part by funds from the Comprehensive Environmental Response, Compensation, and Liability Act trust fund (Superfund) by an interagency agreement with the Agency for Toxic Substances and Disease Registry, U.S . Public Health Service.) Nat Genet, 2002 Sep, 32(1), 97 - 105 Genetics, cytokines and human infectious disease: lessons from weakly pathogenic mycobacteria and salmonellae; Ottenhoff TH et al.; Host genetic factors are important in determining the outcome of infections caused by intracellular pathogens, including mycobacteria and salmonellae, but until now have been poorly characterized . Recently, some individuals with severe infections due to otherwise weakly pathogenic mycobacteria (non-tuberculous mycobacteria or Mycobacterium bovis bacille Calmette-Guerin) or Salmonella species have been shown to be unable to produce or respond to interferon-gamma . This inability results from mutations in any of five genes encoding essential proteins of the type 1 cytokine cascade: interleukin-12p40, interleukin-12R beta 1, interferon-gamma R1, interferon-gamma R2 or STAT1 . Ten syndromes have thus far been identified . Recent insights in genetically controlled host defense and susceptibility to mycobacterial disease are discussed. J Clin Microbiol, 2002 Sep, 40(9), 3530 - 1 A pilot with pain in his leg: thigh abscess caused by Salmonella enterica serotype Brandenburg; Bjorkman P et al.; Salmonella enterica serotype Brandenburg is one of the more uncommon serotypes isolated from patients with gastroenteritis . Few cases of extraintestinal infections with serotype Brandenburg have been documented . The first case of a serotype Brandenburg-dependent thigh abscess originating from an atherosclerotic pseudoaneurysm of the femoral artery is reported. J Clin Microbiol, 2002 Sep, 40(9), 3502 - 5 Persistent endemicity of Salmonella bongori 48:z(35):--in Southern Italy: molecular characterization of human, animal, and environmental isolates; Giammanco GM et al.; From 1984 to 1999, we collected 31 isolates of the rare serovar Salmonella bongori 48:z(35):- in southern Italy . Twenty-four of the isolates were from cases of acute enteritis in humans . Pulsed-field gel electrophoresis analysis showed that all but one of our isolates were at least 80% similar . Our findings suggest that genetically related S . bongori 48:z(35):- strains are endemically circulating in southern Italy. J Clin Microbiol, 2002 Sep, 40(9), 3497 - 8 Technical improvement to prevent DNA degradation of enteric pathogens in pulsed-field gel electrophoresis; Koort JM et al.; This study used a modified pulsed-field gel electrophoresis (PFGE) method with HEPES as a running buffer to prevent electrophoresis-related DNA degradation of nine Salmonella enterica subsp . enterica serovar Ohio, seven Salmonella serovar Newport, and two enterohemorrhagic Escherichia coli (non-O157) strains . All strains yielded identifiable bands with this method in contrast to a commonly applied PFGE method using Tris buffer. J Clin Microbiol, 2002 Sep, 40(9), 3406 - 15 Fluorescent amplified fragment length polymorphism analysis of Salmonella enterica serovar typhimurium reveals phage-type- specific markers and potential for microarray typing; Hu H et al.; Fluorescent amplified fragment length polymorphism (AFLP) was applied to 46 Salmonella enterica serovar Typhimurium isolates of Australian origin comprising nine phage types, by using the restriction enzymes MseI and EcoRI and all 16 possible MseI +1-EcoRI +1 primer pair combinations . AFLP in the present study showed a very good discrimination power with a Simpson index of diversity of 0.98, and 35 different AFLP patterns were observed in the 46 isolates . AFLP grouped most serovar Typhimurium isolates by phage type and enabled differentiation of phage types . Furthermore, 84 phage-type-specific polymorphic AFLP fragments, for which presence or absence correlated with phage type (including 25 with one exception to phage type specificity) were observed in the 46 strains studied . Eighteen phage-type-specific AFLP fragments were cloned and sequenced . Fifteen are of known genes or have a homologue in the databases . Three sequences are plasmid related, eight are phage related, and four relate to chromosomal genes . Twelve of the 18 fragments are polymorphic because the DNA is present or absent as indicated by Southern hybridization, and we see good potential to use sequences of these fragments as the basis for multiplex PCR and development of a microarray-based molecular phage-typing method for serovar Typhimurium. J Clin Microbiol, 2002 Sep, 40(9), 3184 - 91 Molecular characterization of multiresistant d-tartrate-positive Salmonella enterica serovar paratyphi B isolates; Miko A et al.; Since 1996, the National Salmonella Reference Laboratory of Germany has received an increasing number of Salmonella enterica subsp . enterica serovar Paratyphi B isolates . Nearly all of these belonged to the dextrorotatory tartrate-positive variant (S . enterica subsp . enterica serovar Paratyphi B dT(+)), formerly called S . enterica subsp . enterica serovar Java . A total of 55 selected contemporary and older S . enterica subsp . enterica serovar Paratyphi B dT(+) isolates were analyzed by plasmid profiling, antimicrobial resistance testing, pulsed-field gel electrophoresis, IS200 profiling, and PCR-based detection of integrons . The results showed a high genetic heterogeneity among 10 old strains obtained from 1960 to 1993 . In the following years, however, new distinct multiresistant S . enterica subsp . enterica serovar Paratyphi B dT(+) clones emerged, and one clonal lineage successfully displaced the older ones . Since 1994, 88% of the isolates investigated were multiple drug resistant . Today, a particular clone predominates in some German poultry production lines, poultry products, and various other sources . It was also detected in contemporary isolates from two neighboring countries as well. J Clin Microbiol, 2002 Sep, 40(9), 3121 - 6 Emergence of Klebsiella pneumoniae isolates producing inducible DHA-1 beta-lactamase in a university hospital in Taiwan; Yan JJ et al.; Ten nonrepetitive clinical isolates of Klebsiella pneumoniae exhibiting an unusual inducible beta-lactam resistance phenotype were identified between January 1999 and September 2001 in a university hospital in Taiwan . In the presence of 2 micro g of clavulanic acid, the isolates showed a one to four twofold concentration increase in the MICs of ceftazidime, cefotaxime, and aztreonam but remained susceptible to cefepime (MICs, </=0.5 micro g/ml) and imipenem (MICs, </=0.5 micro g/ml) . PCR, sequence analysis, and isoelectric focusing revealed production by these isolates of TEM-1, SHV-11, and DHA-1, a plasmid-encoded inducible AmpC beta-lactamase originally found in a Salmonella enterica serovar Enteritidis strain . Transfer of the resistance by conjugation experiments was not successful, but Southern hybridization showed that bla(DHA-1) was located on 70-kb plasmids, suggesting that the bla(DHA-1)-containing plasmids in the K . pneumoniae isolates were non-self-transmissible . Five isolates were recovered from patients in two surgery wards and two intensive care units . Acquisition of the DHA-1 producers could be traced back to previous hospitalizations 1 to 5 months earlier for the other five patients . Six and seven patterns among the isolates were demonstrated by plasmid analysis and ribotyping, respectively, indicating that the spread of the DHA-1 producers was due to both horizontal transfer of bla(DHA-1) and dissemination of endemic clones. Fish Shellfish Immunol, 2002 Jul, 13(1), 27 - 45 Different bacterial lipopolysaccharides as toxicants and stressors in the shrimp Palaemon elegans; Lorenzon S et al.; This study compares the in vivo haemocytic response of shrimp, Palaemon elegans (Rathke) to different types of LPS injection . In particular it investigates to what degree and speed the haemocytopenia varies between LPSs from different sources . It further compares the tolerated doses of different LPSs in these animals and finds substantial differences in the various toxicity types . The work then relates this to blood glucose levels and stress-linked variations in glycaemic status . The order of LPS decreasing toxicity determined by LD50 at 96 h was: Salmonella enteritidis, Serratia marcescens, Pseudomonas aeruginosa 10, Escherichia coli K-235 and E . coli 0111:B4 . Eyestalkless animals were more sensitive to LPS . The effects of injected LPS on circulating total blood cell count (THC) was tested . The results show that LPS caused a decrease in THC 8 h after injection and then the THC returned to the initial level and this effect depended on the LPS tested . E . coli K-235 was the most effective in causing haemocytopenia followed by E . coli 0111:B4, S . enteritidis, S . marcescens, and P . aeruginosa 10 . Moreover, LPS-induced increases in the blood glucose level and the time and dose related curves of response obtained depended on the type of LPS tested . E . coli K-235 LPS was again the most effective in elevating blood glucose followed by E . coli 0111:B4, S . marcescens, S . enteritidis and then P . aeruginosa 10 . No significant hyperglycaemia was induced in eyestalkless animals . An inverse order relationship between toxicity (LD50) and stress responses (hyperglycaemia and THC decrease) may suggest a defensive and adaptive role of the latter in occasional septicaemia. J Dairy Sci, 2002 Jul, 85(7), 1829 - 38 Relationship between content of crude protein in rations for dairy cows and milk yield, concentration of urea in milk and ammonia emissions; Frank B et al.; During recent decades, efforts have been made in several countries to diminish the negative environmental influence of dairy production . The main focus has been on nitrogen and phosphorus . Modern dairy production in Western Europe is often based on imported feed-stuffs, mostly protein-rich feeds . In Sweden at least, it is wished that the use of imported feedstuffs in animal production will decrease due to the risk of contamination with Salmonella and the ban of using GMO crops in Swedish dairy production . An experiment was carried out to investigate whether a lower content of crude protein in the diet would decrease the ammonia release from cow manure and whether a well-balanced diet using only feedstuffs of Swedish origin would maintain milk production . Five treatments were arranged in a Latin square design . Two different protein supplements made of ingredients of Swedish origin were each fed at two protein levels, and a fifth imported commercial protein mix was fed at the higher level . The treatments with low protein levels (13.1 to 13.5%) had a significantly lower milk yield, kilograms of ECM, but, on the other hand the net profit, milk income minus feed cost was nearly the same in all treatments except diet C, which had lower feed cost but also lower net profit due to lower milk yield . The content of urea in milk was higher with diets high in crude protein (17%) content . A decreased protein level in the diets did not influence the content of casein or whey protein, but the commercial concentrate showed a tendency to give lower values than the Swedish mixtures . The low protein diets gave significantly lower ammonia release from manure compared with the high protein diets . There were no production differences between the diets of Swedish feeds compared with the imported control . The readily fermentable beet pulp should have helped cows use the higher N diet more efficiently and increased the response . This gives the rumen microbes a possibility to match the inflow of protein with carbohydrates . Income over feed costs shows that it is possible to compile diets using products of Swedish origin and still be competitive . On the other hand, this structure may change quickly due to altered world market prices. Cent Afr J Med, 2001 Jun, 47(6), 155 - 8 Anti-Salmonella activity of medicinal plants from Cameroon; Nkuo-Akenji T et al.; OBJECTIVES: To evaluate the effects of herbal extracts derived from plants commonly prescribed by traditional practitioners for the treatment of typhoid fever . DESIGN: A cross sectional study . SETTING: Departments of Life Sciences and Chemistry, University of Buea, Cameroon . SUBJECTS: Methanol extracts of plant parts commonly used in Cameroon for the treatment of typhoid fever . MAIN OUTCOME MEASURES: Antimicrobial activity was tested using the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) assays . RESULTS: Methanol extracts of plant parts commonly used in Cameroon for the treatment of typhoid fever were tested for antibacterial activity against Salmonella typhi, S . paratyphi and S . typhimurium . The formulations used were: 1) Formulation A comprising Cymbogogon citratus leaves, Carica papaya leaves, and Zea mays silk . 2) Formulation B comprising C . papaya roots, Mangifera indica leaves, Citrus limon fruit and C . citratus leaves . 3) C . papaya leaves . 4) Emilia coccinea whole plant . 5) Comelina bengalensis leaves . 6) Telfaria occidentalis leaves . 7) Gossypium arboreum whole plant . Antimicrobial activity was tested using the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) assays . Generally, Formulation A elicited inhibitory activity at a lower range of 0.02 to 0.06 mg/ml . Similarly, Formulation B elicited bacterial activity at the lowest range of 0.06 to 0.25 mg/ml . C . bengalensis leaves on the other hand, showed the lowest activity with a concentration range of 0.132 to 2.0 mg/ml and 1 to 4 mg/ml in MIC and MBC assays respectively . S . paratyphi was most sensitive to the formulations (concentration range of 0.02 to 1 mg/ml in both MIC and MBC assays) while S . typhimurium was the least sensitive and concentrations of up to 4 mg/ml were required to be bactericidal . CONCLUSION: It is concluded that plant extracts with low MIC and MBC values (1 mg/ml and lower) may contain compounds with therapeutic activity. Clin Microbiol Infect, 2002 Jul, 8(7), 427 - 30 Salmonella prosthetic joint septic arthritis; Day LJ et al.; We describe a case of Salmonella enteritidis infection of a prosthetic knee joint that was cured with ceftriaxone therapy for 6 weeks and replacement of the tibial component of the prosthesis . Eleven other cases of salmonella prosthetic joint infection have been reported in the English-language literature . Five infections occurred within 20 days of prosthesis placement, and seven occurred several months to years later; ten of 12 infections involved hip prostheses . Nine of 12 patients who had prosthesis removal were cured of the infection . Two of the three patients with retention of the prosthesis required long-term suppressive antibiotic therapy. East Mediterr Health J, 2000 Sep-Nov, 6(5-6), 1107 - 13 Antibiotic resistance of Moroccan strains of Salmonella enteritidis isolated between 1996 and 1997; Rouahi N et al.; Antimicrobial resistance is a worldwide problem . The antibiotic resistance of Moroccan strains of Salmonella enteritidis was investigated from 1996 to 1997 . A total of 51 strains were collected within this period, 31 derived from human sources and 20 from food . Of the 31 human strains, 10 were resistant to antibiotics; 4 were resistant to two or more antibiotics . Of the 20 food strains, 11 were resistant to antibiotics; 6 were resistant to two or more antibiotics . The results are similar to those obtained from strains isolated from other Mediterranean countries. J Biol Chem, 2002 Nov 1, 277(44), 42151 - 6 Epub 2002 Aug 23. Allosteric enhancement of adaptational demethylation by a carboxyl-terminal sequence on chemoreceptors; Barnakov AN et al.; Sensory adaptation in bacterial chemotaxis is mediated by covalent modification of chemoreceptors . Specific glutamyl residues are methylated and demethylated in reactions catalyzed by methyltransferase CheR and methylesterase CheB . In Escherichia coli and Salmonella enterica serovar typhimurium, efficient adaptational modification by either enzyme is dependent on a conserved pentapeptide sequence at the chemoreceptor carboxyl terminus, a position distant from the sites of modification . For CheR-catalyzed methylation, previous work demonstrated that this sequence acts as a high affinity docking site, enhancing methylation by increasing enzyme concentration near methyl-accepting glutamates . We investigated pentapeptide-mediated enhancement of CheB-catalyzed demethylation and found it occurred by a distinctly different mechanism . Assays of binding between CheB and the pentapeptide sequence showed that it was too weak to have a significant effect on local enzyme concentration . Kinetic analyses revealed that interaction of the sequence and the methylesterase enhanced the rate constant of demethylation not the Michaelis constant . This allosteric activation occurred if the sequence was attached to chemoreceptor, but hardly at all if it was present as an isolated peptide . In addition, free peptide inhibited demethylation of the native receptor carrying the pentapeptide sequence at its carboxyl terminus . These observations imply that the allosteric change is transmitted through the protein substrate, not the enzyme. J Bacteriol, 2002 Sep, 184(18), 4971 - 80 SpiC is required for translocation of Salmonella pathogenicity island 2 effectors and secretion of translocon proteins SseB and SseC; Freeman JA et al.; The Salmonella pathogenicity island 2 (SPI2) type III secretion system (TTSS) promotes Salmonella enterica serovar Typhimurium virulence for mice and increased survival and replication within eukaryotic cells . After phagocytosis, Salmonella serovar Typhimurium assembles the SPI2 TTSS to translocate over a dozen effector proteins across the phagosome membrane . SpiC has been previously shown to be a translocated effector with a large contribution to virulence (K . Uchiya, M . A . Barbieri, K . Funato, A . H . Shah, P . D . Stahl, and E . A . Groisman, EMBO J . 18:3924-3933, 1999) . This report demonstrates by competitive index that the virulence phenotype of a spiC mutant is equivalent to that of a secretion component mutant . In addition, translocation of SPI2 effector proteins was shown to require SpiC . Thus, the severe virulence phenotype resulting from deletion of spiC is likely due to the inability to translocate all SPI2 effectors . SpiC was also required to secrete translocon proteins SseB and SseC but not translocated effector SseJ, indicating that lack of assembly of the translocon explains the spiC mutant phenotype. J Cell Sci, 2002 Sep 15, 115(Pt 18), 3693 - 701 Diverting intracellular trafficking of Salmonella to the lysosome through activation of the late endocytic Rab7 by intracellular delivery of muramyl dipeptide; Mukherjee K et al.; Previously, we showed that live Salmonella-containing phagosomes (LSP) recruit early acting Rab5 and promote fusion with early endosomes, thus avoiding transport to the lysosomes . Therefore, live Salmonella survive in a specialized compartment . Here we show that scavenger-receptor-mediated intracellular delivery of muramyl dipeptide (MDP) to macrophages leads to efficient killing of Salmonella both in vitro and in vivo . To understand the intracellular trafficking modulation of Salmonella by delivery of MDP, we investigated the levels of endocytic Rab proteins, which are the major regulators of vesicular transport . Western blot analysis reveals reduced Rab5 and enhanced Rab7 content in the maleylated bovine serum albumin-MDP (MBSA-MDP)-treated cells . The reduced content of Rab5 in the treated cells and on phagosomes inhibits the fusion of Salmonella-containing phagosomes with early endosomes, and the enhanced Rab7 content in these cells facilitated targeting of LSP to lysosomes, which contain cathepsin D and vacuolar ATPase, for killing . In vitro reconstitution of lysosomal transport demonstrated that a reduced content of Rab5 and an enhanced level of Rab7 in MBSA-MDP-treated cells is primarily responsible for targeting Salmonella to lysosomes . Intracellular delivery of MDP thus offers a general strategy against macrophage-associated infections caused by intracellular pathogens that survive in the host cell by resisting transport to lysosomes. Infect Immun, 2002 Sep, 70(9), 5319 - 21 Identification of genes affecting Salmonella enterica serovar enteritidis infection of chicken macrophages; Zhao Y et al.; Screening of 7,680 Salmonella enterica serovar Enteritidis mutants for attenuation in a chicken macrophage infection model yielded a series of mutants including several with defects in previously unrecognized Salmonella virulence genes . One of the newly identified genes was the pbpA2 gene, belonging to the penicillin binding protein gene family. Infect Immun, 2002 Sep, 70(9), 5312 - 5 Salmonella enterica serovar Typhimurium periplasmic superoxide dismutases SodCI and SodCII are required for protection against the phagocyte oxidative burst; Sly LM et al.; Vitamin D(3) (1,25-dihydroxycholecalciferol) induced the phagocyte oxidative burst and intracellular killing of Salmonella enterica serovar Typhimurium in a phosphatidylinositol 3-kinase-dependent manner . The antimicrobial effect was more pronounced for Salmonella SodCI and SodCII mutants, confirming the role of the phagocyte oxidase in the vitamin D(3) effect . The results for an in vitro system with human THP-1 cells correlate with in vivo virulence data for mice and show that both the SodCI and SodCII enzymes are required to protect against the oxidative burst. Infect Immun, 2002 Sep, 70(9), 5202 - 7 Hydrogen peroxide-mediated killing of Caenorhabditis elegans by Streptococcus pyogenes; Jansen WT et al.; Caenorhabditis elegans is currently introduced as a new, facile, and cheap model organism to study the pathogenesis of gram-negative bacteria such as Pseudomonas aeruginosa and Salmonella enterica serovar Typhimurium . The mechanisms of killing involve either diffusible exotoxins or infection-like processes . Recently, it was shown that also some gram-positive bacteria kill C . elegans, although the precise mechanisms of killing remained open . We examined C . elegans as a pathogenesis model for the gram-positive bacterium Streptococcus pyogenes, a major human pathogen capable of causing a wide spectrum of diseases . We demonstrate that S . pyogenes kills C . elegans, both on solid and in liquid medium . Unlike P . aeruginosa and S . enterica serovar Typhimurium, the killing by S . pyogenes is solely mediated by hydrogen peroxide . Killing required live streptococci; the killing capacity depends on the amount of hydrogen peroxide produced, and killing can be inhibited by catalase . Major exotoxins of S . pyogenes are not involved in the killing process as confirmed by using specific toxin inhibitors and knockout mutants . Moreover, no accumulation of S . pyogenes in C . elegans is observed, which excludes the involvement of infection-like processes . Preliminary results show that S . pneumoniae can also kill C . elegans by hydrogen peroxide production . Hydrogen peroxide-mediated killing might represent a common mechanism by which gram-positive, catalase-negative pathogens kill C . elegans. Infect Immun, 2002 Sep, 70(9), 5096 - 106 Attenuated Salmonella enterica serovar Typhi expressing urease effectively immunizes mice against Helicobacter pylori challenge as part of a heterologous mucosal priming-parenteral boosting vaccination regimen; Londono-Arcila P et al.; Recombinant vaccine strains of Salmonella enterica serovar Typhi capable of expressing Helicobacter pylori urease were generated by transforming strains CVD908 and CVD908-htrA with a plasmid harboring the ureAB genes under the control of an in vivo-inducible promoter . The plasmid did not interfere with the ability of either strain to replicate and persist in human monocytic cells or with their transient colonization of mouse lungs . When administered to mice intranasally, both recombinant strains elicited antiurease immune responses skewed towards a Th1 phenotype . Vaccinated mice exhibited strong immunoglobulin G2a (IgG2a)-biased antiurease antibody responses as well as splenocyte populations capable of proliferation and gamma interferon (IFNgamma) secretion in response to urease stimulation . Boosting of mice with subcutaneous injection of urease plus alum enhanced immune responses and led them to a more balanced Th1/Th2 phenotype . Following parenteral boost, IgG1 and IgG2a antiurease antibody titers were raised significantly, and strong urease-specific splenocyte proliferative responses, accompanied by IFNgamma as well as interleukin-4 (IL-4), IL-5, and IL-10 secretion, were detected . Neither immunization with urease-expressing S . enterica serovar Typhi alone nor immunization with urease plus alum alone conferred protection against challenge with a mouse-adapted strain of H . pylori; however, a vaccination protocol combining both immunization regimens was protective . This is the first report of effective vaccination against H . pylori with a combined mucosal prime-parenteral boost regimen in which serovar Typhi vaccine strains are used as antigen carriers . The significance of these findings with regard to development of a human vaccine against H . pylori and modulation of immune responses by heterologous prime-boost immunization regimens is discussed. Infect Immun, 2002 Sep, 70(9), 5065 - 74 Cruzipain induces both mucosal and systemic protection against Trypanosoma cruzi in mice; Schnapp AR et al.; Cruzipain, the major cysteinyl proteinase of Trypanosoma cruzi, is expressed by all developmental forms and strains of the parasite and stimulates potent humoral and cellular immune responses during infection in both humans and mice . This information suggested that cruzipain could be used to develop an effective T . cruzi vaccine . To study whether cruzipain-specific T cells could inhibit T . cruzi intracellular replication, we generated cruzipain-reactive CD4(+) Th1 cell lines . These T cells produced large amounts of gamma interferon when cocultured with infected macrophages, resulting in NO production and decreased intracellular parasite replication . To study the protective effects in vivo of cruzipain-specific Th1 responses against systemic T . cruzi challenges, we immunized mice with recombinant cruzipain plus interleukin 12 (IL-12) and a neutralizing anti-IL-4 MAb . These immunized mice developed potent cruzipain-specific memory Th1 cell responses and were significantly protected against normally lethal systemic T . cruzi challenges . Although cruzipain-specific Th1 responses were associated with T . cruzi protective immunity in vitro and in vivo, adoptive transfer of cruzipain-specific Th1 cells alone did not protect BALB/c histocompatible mice, indicating that additional immune mechanisms are important for cruzipain-specific immunity . To study whether cruzipain could induce mucosal immune responses relevant for vaccine development, we prepared recombinant attenuated Salmonella enterica serovar Typhimurium vaccines expressing cruzipain . BALB/c mice immunized with salmonella expressing cruzipain were significantly protected against T . cruzi mucosal infection . Overall, these data indicate that cruzipain is an important T . cruzi vaccine candidate and that protective T . cruzi vaccines will need to induce more than CD4(+) Th1 cells alone. Antimicrob Agents Chemother, 2002 Sep, 46(9), 2977 - 81 Characterization of a self-transferable plasmid from Salmonella enterica serotype typhimurium clinical isolates carrying two integron-borne gene cassettes together with virulence and drug resistance genes; Guerra B et al.; An unusual self-transferable virulence-resistance plasmid (pUO-StVR2) was found in nine multidrug-resistant (ACSSuT phenotype) Salmonella enterica serotype Typhimurium clinical isolates that were assigned to four different phage types and a single and distinctive XbaI pulsed-field gel electrophoresis profile . pUO-StVR2 is an IncFII plasmid of about 140 kb in length carrying the spvA, spvB, and spvC (Salmonella plasmid virulence) and rck (resistance to complement killing) genes . It also carries the oxa1/aadA1a (ampicillin resistance and streptomycin-spectinomycin resistance) gene cassette configuration located within a class 1 integron with qacEDelta1/sul1 (ammonium antiseptics resistance and sulfadiazine resistance); the transposon genes merA, tnpA, and tnpR (mercury resistance, transposase, and resolvase of Tn21, respectively); and the catA1 (chloramphenicol resistance) and tet(B) (tetracycline resistance) genes . The insertion of resistance genes into a Salmonella virulence plasmid constitutes a new and interesting example of plasmid evolution and presents a serious public health problem. Antimicrob Agents Chemother, 2002 Sep, 46(9), 2821 - 8 Antibiotic resistance genes and Salmonella genomic island 1 in Salmonella enterica serovar Typhimurium isolated in Italy; Carattoli A et al.; Fifty-four epidemiologically unrelated multidrug-resistant Salmonella enterica serovar Typhimurium isolates, collected between 1992 and 2000 in Italy, were analyzed for the presence of integrons . Strains were also tested for Salmonella genomic island 1 (SGI1), carrying antibiotic resistance genes in DT104 strains . A complete SGI1 was found in the majority of the DT104 strains . Two DT104 strains, showing resistance to streptomycin-spectinomycin and sulfonamides, carried a partially deleted SGI1 lacking the flo(st), tetR, and tetA genes, conferring chloramphenicol-florfenicol and tetracycline resistance, and the integron harboring the pse-1 gene cassette, conferring ampicillin resistance . The presence of SGI1 was also observed in serovar Typhimurium strains belonging to other phage types, suggesting either the potential mobility of this genomic island or changes in the phage-related phenotype of DT104 strains. Psychoneuroendocrinology, 2002 Oct, 27(7), 791 - 804 Potentiation of tumor metastasis in adulthood by neonatal endotoxin exposure: sex differences; Hodgson DM et al.; Previous research in rodents has demonstrated that neonatal exposure to bacterial endotoxin alters the hypothalamic-pituitary-adrenal (HPA) axis resulting in hypersecretion of corticosterone in response to stress in adulthood . Given the known interactions between glucocorticoids and the immune system we tested the hypothesis that such alterations may impact on immune outcomes . Male and female Fischer 344 neonate rats were treated with endotoxin (0.05 mg/kg lipopolysaccaride from Salmonella enteritidis) or vehicle on days 1, 3, 5 and 7 postpartum . In adulthood, animals were subjected to chronic stress and the effect on resistance to tumor colonization (Exp . 1), natural killer (NK) cell activity (Exp . 2), and HPA reactivity (Exp . 3) was assessed . Neonatal endotoxin treatment was found to significantly impair NK cell activity and decrease resistance to tumor colonization in male but not female rats (P<0.05) . Neonatal endotoxin exposure did not affect corticosterone responses to chronic stress in male or female rats, but the corticosterone response to acute stress was potentiated by endotoxin exposure, most notably in females . In conclusion, neonatal endotoxin exposure was found to be associated with a sexually differentiated impairment in tumor colonization and NK activity and long-term alterations in corticosterone responses to stress . The effect on tumor colonization and NK activity was not, however, critically mediated by corticosterone levels . These findings suggest that neonatal bacterial infections may have long-term health implications, specifically in terms of resistance to cancer spread in adulthood . J Food Prot, 2002 Aug, 65(8), 1227 - 32 Application of nested polymerase chain reaction to detection of Salmonella in poultry environment; Liu T et al.; Isolation of Salmonella from environmental and processing-plant poultry samples requires the sampling of large numbers of areas within the poultry house or plant . Subsequently, the required number of samples necessitates a large volume of work for a microbiology laboratory, especially when the protocol requires the inclusion of a delayed secondary enrichment for the isolation of Salmonella . This study examined the use of the polymerase chain reaction (PCR) to identify those secondary enrichments containing Salmonella . The unique Salmonella virulence gene invA was chosen as the target for the development of a nested PCR because of its uniform distribution among Salmonella serotypes . The use of nested PCR primers increased the sensitivity of detection 100-fold, resulting in the detection of as few as four cells . There was a strong, statistically significant positive correlation between PCR and culture results as determined by chi-square (P < 0.001) and kappa (kappa = 0.915; excellent agreement) tests . Using PCR to screen primary enrichments for presumptive Salmonella contamination, we improved our efficiency at isolating Salmonella upon secondary enrichment by 20%, and no false negatives were observed . This method will not only validate the use of secondary enrichment procedures but also reduce costs and manpower required for the surveillance of Salmonella. J Food Prot, 2002 Aug, 65(8), 1215 - 20 Inactivation of Escherichia coli O157:H7, Salmonella enterica serotype enteritidis, and Listeria monocytogenes on lettuce by hydrogen peroxide and lactic acid and by hydrogen peroxide with mild heat; Lin CM et al.; Iceberg lettuce is a major component in vegetable salad and has been associated with many outbreaks of foodborne illnesses . In this study, several combinations of lactic acid and hydrogen peroxide were tested to obtain effective antibacterial activity without adverse effects on sensory characteristics . A five-strain mixture of Escherichia coli O157:H7, Salmonella enterica serotype Enteritidis, and Listeria monocytogenes was inoculated separately onto fresh-cut lettuce leaves, which were later treated with 1.5% lactic acid plus 1.5% hydrogen peroxide (H2O2) at 40 degrees C for 15 min, 1.5% lactic acid plus 2% H2O2 at 22 degrees C for 5 min, and 2% H2O2 at 50 degrees C for 60 or 90 s . Control lettuce leaves were treated with deionized water under the same conditions . A 4-log reduction was obtained for lettuce treated with the combinations of lactic acid and H2O2 for E . coli O157:H7 and Salmonella Enteritidis, and a 3-log reduction was obtained for L . monocytogenes . However, the sensory characteristics of lettuce were compromised by these treatments . The treatment of lettuce leaves with 2% H2O2 at 50 degrees C was effective not only in reducing pathogenic bacteria but also in maintaining good sensory quality for up to 15 days . A < or = 4-log reduction of E . coli O157:H7 and Salmonella Enteritidis was achieved with the 2% H2O2 treatment, whereas a 3-log reduction of L . monocytogenes was obtained . There was no significant difference (P > 0.05) between pathogen population reductions obtained with 2% H2O2 with 60- and 90-s exposure times . Hydrogen peroxide residue was undetectable (the minimum level of sensitivity was 2 ppm) on lettuce surfaces after the treated lettuce was rinsed with cold water and centrifuged with a salad spinner . Hence, the treatment of lettuce with 2% H2O2 at 50 degrees C for 60 s is effective in initially reducing substantial populations of foodborne pathogens and maintaining high product quality. Neurosurgery, 2002 Jul, 51(1), 234 - 7; discussion 237-8 Endovascularly treated cerebral aneurysm using Guglielmi detachable coils acting as a nidus for brain abscess formation secondary to Salmonella bacteremia: case report; Kirollos RW et al.; OBJECTIVE AND IMPORTANCE: Intracranial infections related to the various foreign materials used to secure intracranial aneurysms are extremely rare . The lack of neoendothelium formation across the necks of aneurysms, which is particularly prone to occur when the sac is incompletely packed by Guglielmi detachable coils (GDC), results in the absence of isolation of the coils from the circulation . Colonization of GDCs, which act as a foreign-body nidus after hematogenous spread from infections with bacteremia, may result in localized intracranial infection . CLINICAL PRESENTATION: A 55-year-old woman developed meningitis and a brain abscess surrounding a giant aneurysm that was treated endovascularly with GDC 3 1/2 years earlier . Four weeks before she sought care, she experienced an infective illness with proven Salmonella bacteremia . Salmonella group D was isolated from cerebrospinal fluid . INTERVENTION: The patient was treated successfully with long-term cephalosporin therapy . Follow-up imaging studies revealed regression of the abscess . CONCLUSION: This case suggests that the GDC acted as a colonized foreign body, resulting in the surrounding abscess formation after infection with Salmonella bacteremia . Alternatively, the reaction of the surrounding tissue to the GDC was the predisposing factor and acted as the nidus for the abscess formation. Mol Microbiol, 2002 Aug, 45(4), 1019 - 27 Conflicting needs for a Salmonella hypervirulence gene in host and non-host environments; Mouslim C et al.; The Gram-negative pathogen Salmonella enterica harbours a periplasmic D-Ala-D-Ala dipeptidase (termed PcgL), which confers the ability to grow on D-Ala-D-Ala as sole carbon source . We now demonstrate that inactivation of the pcgL gene renders Salmonella hypervirulent . This phenotype results from the accumulation of peptidoglycan-derived D-Ala-D-Ala in the pcgL mutant and not from an intrinsically faster growth rate . Synthetic D-Ala-D-Ala (but not L-Ala-L-Ala or D-Ala) increased the number of wild-type Salmonella in the liver and spleen of mice within 24 h of injection, suggesting that D-Ala-D-Ala interferes with some aspect of innate immunity . However, the pcgL mutant was unable to grow on D-Ala-D-Ala as sole carbon source and was defective for survival in nutrient-poor conditions . We identified clinical isolates lacking D-Ala-D-Ala dipeptidase activity and unable to grow on D-Ala-D-Ala because of inactivation of the pcgL gene . Our data suggest that genes (such as pcgL) that, when mutated make pathogens more virulent, may be retained because their contribution to pathogen fitness in non-host environments outweighs potential advantages of the hypervirulent vari-ant in the infected host. Mol Microbiol, 2002 Aug, 45(4), 967 - 82 Molecular dissection of Salmonella FliH, a regulator of the ATPase FliI and the type III flagellar protein export pathway; Gonzalez-Pedrajo B et al.; FliH is a soluble component of the flagellar export apparatus that binds to the ATPase FliI, and negatively regulates its activity . The 235-amino-acid FliH dimerizes and interacts with FliI to form a hetero-trimeric (FliH)2FliI complex . In the present work, the importance of different regions of FliH was examined . A set of 24 scanning deletions of 10 amino acids was constructed over the entire FliH sequence, along with several combined deletions of 40 amino acids and truncations of both N- and C-termini . The mutant proteins were examined with respect to (i) complementation; (ii) dominance and multicopy effects; (iii) interaction with wild-type FliH; (iv) interaction with FliI; (v) inhibition of the ATPase activity of FliI; and (vi) interaction with the putative general chaperone FliJ . Analysis of the deletion mutants revealed a clear functional demarcation between the FliH N- and C-terminal regions . The 10-amino-acid deletions throughout most of the N-terminal half of the sequence complemented and were not dominant, whereas those throughout most of the C-terminal half did not complement and were dominant . FliI binding was disrupted by C-terminal deletions from residue 101 onwards, indicating that the C-terminal domain of FliH is essential for interaction with FliI . FliH dimerization was abolished by deletion of residues 101-140 in the centre of the sequence, as were complementation, dominance and interaction with FliI and FliJ . The importance of this region was confirmed by the fact that fragment FliHC2 (residues 99-235) interacted with FliH and FliI, whereas fragment FliHC1 (residues 119-235) did not . FliHC2 formed a relatively unstable complex with FliI and showed biphasic regulation of ATPase activity, suggesting that the FliH N-terminus stabilizes the (FliH)2FliI complex . Several of the N-terminal deletions tested permitted close to normal ATPase activity of FliI . Deletion of the last five residues of FliH caused a fivefold activation of ATPase activity, suggesting that this region of FliH governs a switch between repression and activation of FliI . Deletion of the first 10 residues of FliH abolished complementation, severely reduced its interaction with FliJ and uncoupled its role as a FliI repressor from its other export functions . Based on these data, a model is presented for the domain construction and function of FliH in complex with FliI and FliJ. Vet Rec, 2002 Jul 27, 151(4), 110 - 6 Risk-based evaluation of postmortem inspection procedures for pigs in Australia; Hamilton DR et al.; The results of traditional (incision) and risk-based (visual) postmortem inspection procedures were compared on groups of approximately 30,000 pigs . The performance characteristics used as a basis for comparison included the non-detection rates of grossly detectable abnormalities, the microbiological contamination rates of carcases and boned product, the association of reactive lymph nodes with carcase condemnation and the achievement of 'finished product standards' for 'wholesomeness' . It was estimated that 6 per cent of all cases of abscessation and 28 per cent of all cases of arthritis were undetected by the traditional method, and the comparable figures for the risk-based procedure were 19 per cent and 39 per cent . However, when the rates of contamination of undetected abnormalities with foodborne hazards and other carcase contamination parameters were taken into account, it was concluded that both inspection systems were likely to result in a very similar level of consumer protection . Any increase in potential exposure to foodborne hazards in the abnormalities undetected by risk-based inspection would be insignificant in comparison with the potential exposure to foodborne hazards resulting from contaminated 'normal' lymph nodes and carcase surfaces . There were no statistically significant differences between the two procedures in the contamination rates of pre-chill carcases or boned retail products with Salmonella and Yersinia species. Curr Microbiol, 2002 Sep, 45(3), 226 - 9 In vitro inhibition of Salmonella enterica serovars choleraesuis and typhimurium, Escherichia coli F-18, and Escherichia coli O157:H7 by a porcine continuous-flow competitive exclusion culture; Harvey RB et al.; A competitive exclusion (CE) culture of porcine cecal bacteria was developed as a continuous-flow culture in chemostats, was designated RPCF, and was used as a model to determine its usefulness against in vitro colonization by Salmonella enterica serovars Typhimurium and Choleraesuis, Escherichia coli strain F-18, and E . coli serotype O157:H7 (933) . Chemostats with or without RPCF were inoculated with 10(6) colony-forming units (CFU)/ml of Typhimurium, Choleraesuis, F-18, or O157:H7 . Chemostats were sampled for salmonellae and E . coli at 15 min, 7 h, and every 24 h thereafter . In control chemostats without RPCF, Typhimurium, Choleraesuis, F-18, and O157:H7 rapidly established colonization and had concentrations of 10(6) CFU/ml for 96-120 h post-inoculation . In the chemostats that contained RPCF, reductions (P < 0.05) of Choleraesuis, F-18, and O157:H7 were observed at 24 h post-inoculation . Typhimurium was decreased (P < 0.05) at 48 h post-inoculation, and by 120 h post-inoculation, all chemostats were negative for the four challenge microorganisms . These results demonstrate that RPCF cultures were able to inhibit the growth of Typhimurium, Choleraesuis, and E . coli strains F-18 and O157:H7 in vitro and suggest the potential for the use of CE in swine to prevent disease induced by these microorganisms. Proc Natl Acad Sci U S A, 2002 Aug 20, 99(17), 11260 - 4 Epub 2002 Aug 12. MHC heterozygosity confers a selective advantage against multiple-strain infections; Penn DJ et al.; Genetic heterozygosity is thought to enhance resistance of hosts to infectious diseases, but few tests of this idea exist . In particular, heterozygosity at the MHC, the highly polymorphic loci that control immunological recognition of pathogens, is suspected to confer a selective advantage by enhancing resistance to infectious diseases (the "heterozygote advantage" hypothesis) . To test this hypothesis, we released mice into large population enclosures and challenged them with multiple strains of Salmonella and one of Listeria . We found that during Salmonella infections with three avirulent strains, MHC heterozygotes had greater survival and weight than homozygotes (unlike sham controls), and they were more likely to clear chronic Salmonella infection than homozygotes . In laboratory experiments, we found that MHC heterozygosity enhanced the clearance of multiple-strain Salmonella infections . Yet, contrary to what is widely assumed, the benefits of heterozygosity were due to resistance being dominant rather than overdominant, i.e., heterozygotes were more resistant than the average of parental homozygotes, but they were not more resistant than both . The fact that MHC heterozygotes were more resistant to infection and had higher fitness than homozygotes provides a functional explanation for MHC-disassortative mating preferences. Food Chem Toxicol, 2002 Nov, 40(11), 1603 - 10 Genotoxicity of gardenia yellow and its components; Ozaki A et al.; Gardenia fruit (Gardenia jasminoides ELLIS) is widely used as a natural food colorant and as a traditional Chinese medicine for treatment of hepatic and inflammatory diseases . "Gardenia yellow" is a natural food colorant which is extracted by ethanol from gardenia fruit . The purpose of this study was to evaluate the genotoxicity of gardenia yellow . Genotoxicity of gardenia yellow and its components, crocetin, gentiobiose (a component of crocin), geniposide and genipin (formed by hydrolysis of geniposide), was studied by Ames test, rec-assay, and sister chromatid exchange (SCE) using V79 cells . Gardenia yellow and its components were found not to be mutagenic in the Salmonella reverse mutation assay . Gardenia yellow and genipin caused damage of DNA in rec-assay . Gardenia yellow induced a significant dose-dependent increase of SCE frequency (8.6 times at 1000 microg/ml as the value for the solvent control) . Only genipin induced SCEs significantly among the components of gardenia yellow . Moreover, genipin induced a significant increase of tetraploids at all doses tested (95% at 8 microg/ml) . Gardenia yellow preparation was analyzed by capillary electrophoresis (CE), and geniposide was detected . However, genipin was not observed . In conclusion, we have shown that genipin possesses genotoxicity . Furthermore, there were unidentified genotoxicants in gardenia yellow. Berl Munch Tierarztl Wochenschr, 2002 Jul-Aug, 115(7-8), 252 - 8 {Report on Salmonella isolates submitted to the German National Veterinary Salmonella Reference Laboratory in the year 1999}; Dorn C et al.; The National Salmonella Reference Laboratory (NRL-Salm) of the Federal Institute for Health Protection of Consumers and Veterinary Medicine receives putative Salmonella isolates originating from animals, food, feed and the environment for typing . This report summarises the results of the sero- and phagetyping studies . In livestock S . Typhimurium DT 104 with 24% and S . Enteritidis PT 4 with 9% of all isolations predominate like in the human isolates . These sero- and phagetypes are frequently isolated from food as well and consequently can reach the consumer via the food chain. AIDS, 2002 Aug 16, 16(12), 1633 - 41 Non-typhoidal salmonella bacteraemia among HIV-infected Malawian adults: high mortality and frequent recrudescence; Gordon MA et al.; OBJECTIVE: Non-typhoidal salmonella (NTS) bacteraemia is a common, recurrent illness in HIV-infected African adults . We aimed to describe the presentation and outcome of NTS bacteraemia, the pattern of recurrence, and to determine whether recurrence results from re-infection or recrudescence . DESIGN: One hundred consecutive adult inpatients with NTS bacteraemia in Blantyre, Malawi, were treated with chloramphenicol . Survivors were prospectively followed to detect bacteraemic recurrence . METHODS: Index and recurrent isolates were typed by antibiogram, pulsed-field gel electrophoresis and plasmid analysis to distinguish recrudescence from re-infection . RESULTS: Inpatient mortality was 47%, and 1-year mortality was 77% . A total of 77 out of 78 cases were HIV positive . Anaemia was associated with inpatient death, and several features of AIDS were associated with poor outpatient survival . Among survivors, 43% (19/44) had a first recurrence of NTS bacteraemia at 23-186 days . Among these, 26% (5/19) developed multiple recurrences up to 245 days . No recurrence was seen after 245 days, despite follow-up for up to 609 days (median 214) . Suppurative infections were not found at presentation, and were only seen twice at recurrence . Index and recurrent paired isolates were identical by phenotyping and genotyping, consistent with recrudescence, rather than re-infection . CONCLUSION: NTS bacteraemia has a high mortality (47%) and recurrence (43%) rate in HIV-infected African adults . Recurrence is caused by recrudescence rather than re-infection . As focal infections were rarely found, recrudescence may often be a consequence of intracellular tissue sequestration . There is an urgent need for improved primary treatment and secondary prophylaxis in Africa. Am J Vet Res, 2002 Aug, 63(8), 1145 - 50 Hematologic and serum biochemical changes in Salmonella ser Typhimurium-infected calves; Santos RL et al.; OBJECTIVE: To evaluate hematologic and serum biochemical changes in Salmonella ser Typhimurium-infected calves . ANIMALS: 16 male 3- to 4-week-old dairy calves . PROCEDURE: 13 calves were experimentally infected with S Typhimurium (strains IR715 and CS401, which are derivatives of ATCC 14028), and 3 calves were uninfected controls . Several hematologic and serum biochemical parameters were measured . RESULTS: Hematologic changes included increases in PCV, RBC count, and hemoglobin concentration, associated with a transitory leukopenia characterized by neutropenia and lymphopenia . Biochemical findings included hypoglycemia, increased BUN, creatinine, and fibrinogen concentrations, and decreased sodium, total CO2, calcium, total protein, and albumin concentrations . Increased total bilirubin concentration associated with decreased conjugated bilirubin concentration was also observed . No significant changes in aspartate aminotransferase, gamma-glutamyltranspeptidase, alkaline phosphatase, and creatinine kinase activities were detected . CONCLUSIONS AND CLINICAL RELEVANCE: Experimental salmonellosis of calves results in marked to severe dehydration, accompanied by metabolic acidosis, hypoglycemia, and an acute inflammatory response associated with increased fibrinogen concentrations and severe neutropenia immediately after inoculation. J Bacteriol, 2002 Sep, 184(17), 4699 - 708 Salmonella type III secretion-associated protein InvE controls translocation of effector proteins into host cells; Kubori T et al.; Salmonella enterica encodes a type III secretion system (TTSS) within a pathogenicity island located at centisome 63 (SPI-1), which is essential for its pathogenicity . This system mediates the transfer of a battery of bacterial proteins into the host cell with the capacity to modulate cellular functions . The transfer process is dependent on the function of protein translocases SipB, SipC, and SipD . We report here that Salmonella protein InvE, which is also encoded within SPI-1, is essential for the translocation of bacterial proteins into host cells . An S . enterica serovar Typhimurium mutant carrying a loss-of-function mutation in invE shows reduced secretion of SipB, SipC, and SipD while exhibiting increased secretion of other TTSS effector proteins . We also demonstrate that InvE interacts with a protein complex formed by SipB, SipC, and their cognate chaperone, SicA . We propose that InvE controls protein translocation by regulating the function of the Sip protein translocases. Commun Dis Public Health, 2002 Jun, 5(2), 101 - 5 General outbreaks of infectious intestinal disease linked with salad vegetables and fruit, England and Wales, 1992-2000; Long SM et al.; Between 1992 and 2000, 1,518 foodborne general outbreaks of infectious intestinal disease (IID) were reported to the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC), of which 83 (5.5%) were associated with the consumption of salad vegetables or fruit (SVF) . The pathogens most frequently reported were salmonellas (41.0%) and Norwalk-like virus (NLV) (15.7%) . In total 3,438 people were affected; 69 were admitted to hospital and one person died . Most outbreaks were linked to commercial catering premises (67.5%) . Three community outbreaks, of Salmonella enterica serovar Typhimurium Definitive Phage Type (DT) 104, S . Typhimurium DT 204b and Shigella sonnei infection, were found to be associated with lettuce contaminated at source, and these accounted for 501 (14.6%) cases . The latter two outbreaks were international, involving several European countries . This demonstrates how contamination of SVF during production/processing can result in major, geographically widespread, outbreaks of infection with serious public health consequences. J Mol Evol, 2002 Jul, 55(1), 37 - 51 Characterization of the ysa pathogenicity locus in the chromosome of Yersinia enterocolitica and phylogeny analysis of type III secretion systems; Foultier B et al.; Several Gram negative bacteria use a complex system called "type III secretion system" (TTSS) to engage their host . The archetype of TTSS is the plasmid-encoded "Yop virulon" shared by the three species of pathogenic Yersinia (Y . pestis, Y . pseudotuberculosis, and Y . enterocolitica) . A second TTSS, called Ysa (for Yersinia secretion apparatus) was recently described in Y . enterocolitica 8081, a strain from serotype O:8 . In this study, we describe the ysa locus from A127/90, another strain of serotype O:8, and we extend the sequence to several new genes encoding Ysp proteins which are the substrates of this secretion system, and a putative chaperone SycB . According to the deduced protein sequences, the ysa system from A127/90 is identical to that of 8081 . It is different from the chromosome-encoded TTSS of Y . pestis but is instead closely related to the Mxi-Spa TTSS of Shigella and to the SPI-1 encoded TTSS of Salmonella enterica . We further demonstrated that the ysa locus is only present in biotype IB strains of Y . enterocolitica . Including this new Ysa system, a phylogenetic analysis of the 26 known TTSSs was carried out, based on the sequence analysis of three conserved proteins . All the TTSSs fall into five different clusters . The phylogenetic tree of these TTSSs is completely different from the evolutionary tree based on 16S RNA, indicating that TTSSs have been distributed by horizontal transfer. Rev Gastroenterol Peru, 1996 Sep-Dec, 16(3), 214 - 21 {Enteropathogenic agents isolated in persistent diarrhoea}; Lopez Marin D et al.; Out of 45558 patients admited in our hospital, from January 1990 to December 1993, the clinical records of 4445 children with diarrhoea (4289 with acute diarrihoea and 156 with persistent diarrhoea) were reviewed . Those with positive bacteriological or parasitological results were taken as sample.Salmonella was the bacteria most frequently isolated in both groups of patients . ECEP and ECEH had a similar distribution while Shigella showed a higher frequency in cases of persistent diarrhoea, for a third pace of incidence.From the parasitological point of view, Cryptosporidium and Giardia had the same behavior. J Immunol, 2002 Aug 15, 169(4), 2196 - 203 Characterization of CD8(+) effector T cell responses in volunteers immunized with Salmonella enterica serovar Typhi strain Ty21a typhoid vaccine; Salerno-Goncalves R et al.; Salmonella enterica serovar Typhi (S . typhi) strain Ty21a remains the only licensed attenuated typhoid vaccine . Despite years of research, the identity of the protective immunological mechanisms elicited by immunization with the Ty21a typhoid vaccine remains elusive . The present study was designed to characterize effector T cell responses in volunteers immunized with S . typhi strain Ty21a typhoid vaccine . We determined whether immunization with Ty21a induced specific CTL able to lyse S . typhi-infected cells and secrete IFN-gamma, a key effector molecule against intracellular pathogens . We measured the functional activity of these CTL by a (51)Cr-release assay using 8-day restimulated PBMC from Ty21a vaccinees as effector cells and S . Typhi-infected autologous PHA-activated PBMC as target cells . Most vaccinees exhibited consistently increased CD8-mediated lysis of targets by postimmunization PBMC when compared with preimmunization levels . We also developed an IFN-gamma ELISPOT assay to quantify the frequency of IFN-gamma spot-forming cells (SFC) in PBMC from Ty21a vaccinees using an ex vivo system . Significant increases in the frequency of IFN-gamma SFC following immunization (mean +/- SD, 393 +/- 172; range 185-548 SFC/10(6) PBMC; p = 0.010), as compared with preimmunization levels, were observed . IFN-gamma was secreted predominantly by CD8(+) T cells . A strong correlation was recorded between the cytolytic activity of CTL lines and the frequency of IFN-gamma SFC (r(2) = 0.910, p < 0.001) . In conclusion, this work constitutes the first evidence that immunization of volunteers with Ty21a elicits specific CD8(+) CTL and provides an estimate of the frequency of CD8(+) IFN-gamma-secreting cells induced by vaccination. Am J Trop Med Hyg, 2002 Apr, 66(4), 416 - 21 Simple dipstick assay for the detection of Salmonella typhi-specific IgM antibodies and the evolution of the immune response in patients with typhoid fever; Hatta M et al.; Application of a dipstick assay for the detection of Salmonella typhi-specific IgM antibodies on samples collected from S . typhi or S . paratyphi culture-positive patients at the day of admission to the hospital revealed the presence of specific IgM antibodies in 43.5%, 92.9%, and 100% for samples collected 4-6 days, 6-9 days, and > 9 days after the onset of fever, respectively . The mean sensitivity for samples collected an average of 6.6 days after the onset of fever was 65.3% . Culture was positive in 65.9% of the cases with a final clinical diagnosis of typhoid fever . Testing of paired serum samples from culture negative patients with a final clinical diagnosis of typhoid fever resulted in staining of the dipstick in 4.3% of the samples collected at the day of admission to the hospital and in 76.6% of the samples collected one week later, thereby provided strong supporting evidence of typhoid fever by demonstrating seroconversion in a large proportion of the patients . The dipstick assay may thus also be useful for the serodiagnosis of culture-negative patients with clinical signs and symptoms consistent with typhoid fever . The advantages of the dipstick assay are that the result can be obtained on the same day allowing a prompt treatment, that only a small volume of serum is needed, and that no special laboratory equipment is needed to perform the assay . The stability of the reagents of the dipstick and the simplicity of the assay allows its use in places that lack laboratory facilities. Biosci Biotechnol Biochem, 2002 Jun, 66(6), 1400 - 2 Antimutagenic effect of amino acids on the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG); Roy MK et al.; The antimutagenic activity of protein-constituting amino acids except histidine on the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated in vitro using Salmonella typhinurium TA-100 as an indicator bacterium (Ames test), and concentrations (IC50) of amino acids that inhibit 50% of the mutagenecity were measured . Cysteine was found to be most active and glycine, tryptophan, lysine, and arginine were strong antimutagenic amino acids . Other amino acids showed moderate or weak antimutagenic activities, depending on the amino acids . The results indicate that amino acids play a substantial role in chemoprevention of N-nitroso amine-induced mutagenicity. Mutat Res, 2002 Aug 26, 519(1-2), 205 - 9 Mutagenicity of emissions from a natural gas fueled truck; Lapin CA et al.; Concern about the potential health risks of particulate exhaust emissions from diesel-fueled vehicles has led regulatory agencies to foster the use of natural gas fueled heavy duty vehicles . However, the potential health risks of particulate exhaust emissions from natural gas fueled vehicles have not been well-studied . The present study investigated the mutagenicity of particulate exhaust emissions from a natural gas fueled refuse truck currently in-service . Organic solvent extracts of exhaust particulate emissions from the natural gas fueled truck were positive in both Salmonella tester strains TA98 and TA100 in the presence and absence of S-9 . The maximum mutagenic responses ranged from 7-fold in the TA100 strain to 87-fold in the TA98 strain when compared to negative controls . Our results show that current in-service natural gas fueled heavy duty trucks have particulate exhaust emissions that possess mutagenic activity . This finding requires follow-up studies to develop a database on natural gas fueled vehicles for comparison with data on diesel-fueled vehicles to aid in making decisions on use of alternative fuels to reduce air pollution health risks. Mutat Res, 2002 Aug 26, 519(1-2), 67 - 74 Comparison of the Ames test and a newly developed assay for detection of mutagenic pollution of marine environments; Czyz A et al.; A new assay for detection of mutagenic pollution of marine environments, based on the use of a series of genetically modified Vibrio harveyi strains, was developed recently . Here, we compared this assay with a commonly used Ames test, employing mutants of Salmonella enterica serovar Typhimurium . We found that survival of S . enterica serovar Typhimurium in artificial marine water and in different samples of marine water is dramatically reduced relative to that of V . harveyi strains . This indicates that V . harveyi strains are significantly more useful in testing samples of marine water . Moreover, sensitivity of both assays was compared . We found that using the V . harveyi assay it is possible to detect significantly (from a few to several times) lower concentrations of typical chemical mutagens than employing the Ames test . Although the higher sensitivity of the V . harveyi test relative to the Ames assay may be of minor importance when testing mutagenicity of certain chemicals in their pure form under laboratory conditions, this feature is very important in testing samples of marine water . Therefore, we assume that the V . harveyi assay may be an adequate test for detection of mutagenic pollution of marine environments. Res Microbiol, 2002 Jun, 153(5), 281 - 7 Role of trehalose biosynthesis in environmental survival and virulence of Salmonella enterica serovar typhimurium; Howells AM et al.; The otsA and otsB genes, encoding trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase respectively, have been isolated from Salmonella enterica serovar typhimurium and nucleotide-sequenced . Induction of trehalose biosynthesis by exposure of bacteria to high osmotic strength resulted in the intracellular accumulation of trehalose . An otsA mutant of S . enterica serovar typhimurium was more susceptible to killing by heat, and grew poorly under conditions of high osmolarity . The wild-type and otsA mutant strains showed similar abilities to colonise spleen tissues after oral dosing of mice . These findings suggest that the otsBA gene products play a role in environmental survival, but not in virulence, of S . enterica serovar typhimurium. Int J Food Microbiol, 2002 Aug 25, 77(3), 223 - 31 Survival of Escherichia coli O157:H7 and Salmonella Muenchen on apples as affected by application of commercial fruit waxes; Kenney SJ et al.; Survival of Escherichia coli O157:H7, Salmonella Muenchen, and yeasts and molds on apples as affected by application of five commercial apple waxes was investigated . Red Delicious cv . apples at 21 degrees C were spot inoculated with E . coli O157:H7 and S . Muenchen and spray coated with waxes . Apples sprayed with water served as controls . Apples were dried at either 21 or 55 degrees C for 2 min before subjecting to microbiological analysis after storage for 0, 1, 3, 6, and 12 weeks at 2 or 21 degrees C . Drying temperature did not significantly influence populations of E . coli O157:H7 and S . Muenchen . Waxing reduced populations E . coli O157:H7 and S . Muenchen by up to 1.48 log10 cfu/apple . Compared to untreated apples, treatment of apples with water or waxes resulted in significant (P < or = 0.05) reductions in populations of E . coli O157:H7 and S . Muenchen during storage at 2 degrees C . Reductions on waxed apples stored at 21 degrees C were not as marked compared to reductions on waxed apples stored at 2 degrees C . With the exception of one wax, drying temperature did not significantly influence populations of yeasts and molds . Mold populations were less affected by wax applications than were yeasts, and were detected in higher numbers on apples treated with three of the five waxes compared to populations recovered from untreated control apples . None of the waxes evaluated can be relied upon to kill or remove E . coli O157:H7 and Salmonella on apples. Int J Food Microbiol, 2002 Aug 25, 77(3), 199 - 204 Bacteriological analysis of fresh produce in Norway; Johannessen GS et al.; A total of 890 samples of fresh produce obtained from Norwegian markets were examined in order to assess the bacteriological quality of the products and their potential public health risk . The samples comprised lettuce, pre-cut salads, growing herbs, parsley and dill, mushrooms and strawberries . The samples were analysed for the presence of thermotolerant coliform bacteria (TCB), Escherichia coli O157, Salmonella spp., Listeria monocytogenes, Staphylococcus spp., and Yersinia enterocolitica . Neither Salmonella spp . nor E . coli O157 were isolated . For all product groups included, TCB were isolated from a small proportion of samples . Three samples harboured L . monocytogenes; one of the isolates belonging to serogroup 1 (champignons) and two of the isolates belonging to serogroup 4 (Chinese leaves and strawberries) . Staphylococci were isolated from a relatively large proportion of the samples of strawberries and mushrooms . However, only four isolates were identified as S . aureus (non-toxinogenic) . By the use of PCR, the presence of Y . enterocolitica was indicated in a few of the samples of lettuce, whilst no positive samples were found using a culturing method . The study shows that the occurrence of pathogenic bacteria and TCB in the products analysed was quite low . Nevertheless, the results indicate that the type of products analysed may contain pathogenic bacteria and thereby represent a risk to the consumers in regard to food-borne diseases. Plasmid, 2002 May, 47(3), 159 - 71 Characterisation and distribution of a cryptic Salmonella typhi plasmid pHCM2; Kidgell C et al.; pHCM2 is a 106 kbp cryptic plasmid harboured by Salmonella typhi CT18, originally isolated from a typhoid patient in Vietnam . The genome of S . typhi CT18, including pHCM2, has recently been completely sequenced and annotated . Bioinformatic analysis revealed that 57% of the coding sequences (CDSs) encoded on pHCM2 display over 97% DNA sequence identity to the virulence-associated plasmid of Yersinia pestis, pFra . pHCM2 encodes no obvious virulence-associated determinants or antibiotic resistance genes but does encode a wide array of putative genes directly related to DNA metabolism and replication . PCR analysis of a series of S . typhi isolates from Vietnam detected pHCM2-related DNA sequences in some S . typhi isolated before, but not after, 1994 . Similar pHCM2-related sequences were also detected in S . typhi isolated from other regions of South East Asia and Pakistan but not elsewhere in the world. J Clin Microbiol, 2002 Aug, 40(8), 3050 - 2 Real-time PCR detection of salmonella in suspect foods from a gastroenteritis outbreak in kerr county, Texas; Daum LT et al.; In June 2001, an outbreak of acute gastroenteritis among 109 attendees of a church picnic in Kerr County, Texas, was reported . A 5'-nuclease PCR assay was used to screen for Salmonella in nine food items from the buffet line . Barbeque chicken B tested positive for Salmonella, and no amplification was detected in the remaining food items . These PCR findings were consistent with culture results and were confirmed by direct nucleotide sequencing . Salmonella enterica serotype Panama was cultured from both food and patient stool samples. J Clin Microbiol, 2002 Aug, 40(8), 2999 - 3003 Comparison of CHROMagar Salmonella medium and xylose-lysine-desoxycholate and Salmonella-Shigella agars for isolation of Salmonella strains from stool samples; Maddocks S et al.; The growth and appearance of 115 stock Salmonella isolates on a new formulation of CHROMagar Salmonella (CAS) medium were compared to those on xylose-lysine-desoxycholate agar (XLD), Salmonella-Shigella agar (SS), and Hektoen enteric agar (HEA) media . CAS medium was then compared prospectively to XLD and SS for the detection and presumptive identification of Salmonella strains in 500 consecutive clinical stool samples . All stock Salmonella isolates produced typical mauve colonies on CAS medium . Nine Salmonella strains were isolated from clinical specimens . The sensitivities for the detection of salmonellae after primary plating on CAS medium and the combination of XLD and SS after enrichment were 100% . The specificity for the detection of salmonellae after primary plating on CAS medium (83%) was significantly (P < 0.0001) higher than that after primary plating on the combination of SS and XLD media (55%) (a 28% difference in rates; 95% confidence interval, 23.0 to 34%) . Twenty-nine non-Salmonella org