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detection of lawsonia intracellularis, serpulina hyodysenteriae, weakly beta-haemolytic intestinal spirochaetes, salmonella enterica, and haemolytic escherichia coli from swine herds with and without diarrhoea among growing pigs.a polymerase chain reaction (pcr) was optimized to detect lawsonia intracellularis in faeces from naturally infected pigs. by combining a boiling procedure to extract dna and a nested pcr procedure, a detection limit at 2 x 10(2) bacterial cells per gram of faeces was achieved. the optimized pcr was used together with conventional culture techniques to detect serpulina hyodysenteriae, weakly beta-haemolytic intestinal spirochaetes (wbhis), salmonella enterica, and haemolytic escherichia coli, in ...19989659692
interpretations of antibody responses to salmonella enterica serotype enteritidis gm flagellin in poultry flocks are enhanced by a kinetics-based enzyme-linked immunosorbent assay.many regulatory and diagnostic programs for the detection of salmonella enterica serotype enteritidis infection in commercial poultry flocks have relied on rapid pullorum agglutination tests to screen birds because of the shared antigens of s. enterica enteritidis and s. enterica pullorum and gallinarum; however, the use of the enzyme-linked immunosorbent assay (elisa) format affords better analytical sensitivity than crude agglutination tests. in this study, we adapted our earlier conventional ...19989665965
characterization of a neutralizing monoclonal antibody directed at the lipopolysaccharide of chlamydia pneumoniae.identification of protective epitopes is one of the first steps in the development of a subunit vaccine. one approach to accomplishing this is to identify structures or epitopes by using monoclonal antibodies (mab) that can attenuate infectivity in vitro and in vivo. to date attempts to use this approach with chlamydia pneumoniae have failed. this report is the first description of a mab directed to the lipopolysaccharide (lps) of chlamydia that neutralizes both in vitro and in vivo the infectiv ...19989673271
enteric bacterial pathogens, villus atrophy and microbial growth.the effects of three bacterial pathogens on the villus architecture of small intestines and the role that bacterial virulence factors play in pathogenesis are described. bacterial pathogens cause a spectrum of effects ranging from severe tissue damage to a lack of perceptible damage. enterotoxigenic escherichia coli, which cause acute and severe diarrhea, does so by producing potent toxins, but these toxins act by altering the biological activity in epithelial cells. however, the cells are not d ...19989689730
experimental and natural infection of early weaned pigs with salmonella choleraesuis.a model for experimental and natural infection of early weaned pigs with salmonella choleraesuis, the aetiologic agent of swine paratyphoid, has been developed. an oral dose of 10(8) colony forming units (cfu) of s choleraesuis caused 100 per cent infection of 10 pigs inoculated, as indicated by recovery of the challenge organism from ileocolic lymph nodes collected at necropsy seven days post challenge. seven of the pigs were observed shedding s choleraesuis at least once post s choleraesuis ch ...19989690614
[the roles of heat shock proteins in host defense against bacterial infection].heat shock proteins (hsp) are widely distributed in nature, and are highly conserved proteins among prokaryotes and eukaryotes. these proteins are known to be involved in cytoprotection against various stress conditions including bacterial infection, and immune responses to various pathogens such as bacteria. in this study, we showed that hsp70 protected macrophages infected with salmonella choleraesuis against tnf-alpha-induced cell death. furthermore, hsp70-reactive cd4+ t cells appeared durin ...19989691765
a community-based outbreak of salmonella enterica serotype typhimurium associated with salami consumption in northern italy.an outbreak of salmonella enterica serotype typhimurium belonging to phage type (pt) 193 occurred in autumn 1995 and involved 83 individuals in a large area of northern italy (lombardy region). epidemiological and microbiological investigations of strains isolated from clinical and food specimens revealed that the vehicle was a batch of salami, produced on 4 september 1995 by a local firm. the outbreak was contained when the batch was withdrawn from sale. insufficient ripening of the salami had ...19989692597
is200 fingerprint of salmonella enterica serotype typhimurium human strains isolated in sardinia.a collection of salmonella enterica serotype typhimurium human strains isolated in northern sardinia (italy) was examined for the insertion sequence is200, phage type, antibiotic profile, ribotyping polymorphisms and plasmid profile. all clinical isolates studied contained from 4 to 10 copies of the is200 element. is200 permitted to discriminate typhimurium strains and to identify five is200 types, some of them circulating in sardinia at least since 1900. strains belonging to phage dt104 predomi ...19989692598
epidemiological analysis of salmonella enterica enteritidis isolates in japan by phage-typing and pulsed-field gel electrophoresis.salmonella enterica serotype enteritidis isolates of phage types (pts) pt1, pt4, pt13a and pt22 derived from sporadic cases and outbreaks of food poisoning in japan during 1994 and 1995 were analysed by pulsed-field gel electrophoresis (pfge). while pt1 strains from 5 different outbreaks showed 14 pfge patterns, 5 pfge patterns were observed among pt4 isolates from 5 different outbreaks and 6 independent isolates from imported chicken. interestingly, 8 out of 9 pt4 strains associated with foreig ...19989692599
antibiotic resistance amongst salmonella enterica species isolated in the republic of ireland. 19989700542
expression of the o antigen gene cluster is regulated by rfah through the jumpstart sequence.o antigen genes are clustered, with a jumpstart sequence located upstream. jumpstart is a 39-bp sequence, present upstream of many polysaccharide gene clusters and also upstream of haemolysin and f factor gene clusters. rfah is known to regulate the expression of e. coli group ii capsule, haemolysin, f factor and the outer core of lipopolysaccharide all of which have the jumpstart sequence, and has been shown to function as a transcriptional antiterminator in some cases. using lacz fusions to ge ...19989711858
low endotoxic potential of legionella pneumophila lipopolysaccharide due to failure of interaction with the monocyte lipopolysaccharide receptor cd14.legionella pneumophila, a gram-negative bacterium causing legionnaires' disease and pontiac fever, was shown to be highly reactive in in vitro gelation of limulus lysate but not able to induce fever and the local shwartzman reaction in rabbits and mice. we analyzed the capacity of purified l. pneumophila lipopolysaccharide (lps-lp) to induce activation of the human monocytic cell line mono mac 6, as revealed by secretion of proinflammatory cytokines and desensitization to subsequent lps stimulat ...19989712761
successful treatment of murine listeriosis and salmonellosis with levofloxacin.levofloxacin (l-ofloxacin) is a fluoroquinolone derivative. it is the active substance contained in ofloxacin with a broad spectrum of antibacterial activity against both gram-negative and gram-positive bacteria. in this work we examined the activity of levofloxacin against the facultative intracellular bacteria listeria monocytogenes and salmonella typhimurium in vitro, in tissue culture and in animal models of infection. the minimum inhibitory concentrations (mics) mic90 for salmonella enteric ...19989720471
characterisation of recently emerged multiple antibiotic-resistant salmonella enterica serovar typhimurium dt104 and other multiresistant phage types from danish pig herds.a total of 670 isolates of salmonella enterica were isolated from danish pig herds, phage typed and tested for susceptibility to amoxycillin + clavulanate, ampicillin, colistin, enrofloxacin, gentamicin, neomycin, spectinomycin, streptomycin, tetracyclines, and trimethoprim + sulphadiazine. s enterica serovar typhimurium (s typhimurium) isolates resistant to ampicillin, streptomycin and tetracycline and three isolates of s typhimurium dt104, two from 1994 and one from 1995, were further tested f ...19989725173
phylogenetic relationships of salmonella based on rrna sequences.to establish the phylogenetic relationships between the subspecies of salmonella enterica (official name salmonella choleraesuis), salmonella bongori and related members of enterobacteriaceae, sequence comparison of rrna was performed by maximum-likelihood analysis. the two salmonella species were separated by 16s rrna analysis and found to be closely related to the escherichia coli and shigella complex by both 16s and 23s rrna analyses. the diphasic serotypes s. enterica subspp. i and vi were s ...19989731304
multiple antibiotic resistance in salmonella enterica serotype enteritidis. 19989734924
restriction fragment length polymorphism analysis of some flagellin genes of salmonella enterica.salmonellae often have the ability to express two different flagellar antigen specificities (phase 1 and phase 2). at the cell level, only one flagellar phase is expressed at a time. two genes, flic, encoding phase-1 flagellin, and fljb, encoding phase-2 flagellin, are alternatively expressed. flagellin genes from 264 serovars of salmonella enterica were amplified by two phase-specific pcr systems. amplification products were subjected to restriction fragment length polymorphism (rflp) analysis ...19989738029
[agglutination of hen egg-yolk immunoglobulins (igy) against salmonella enterica, serovar enteritidis].two groups of 6 laying hens were used to produce igy. in the vaccinated group (v), hens were injected by intramuscular route with two doses of a salmonella enterica serovar enteritidis bacterin at 20-day interval. in the control group (t) hens remained unvaccinated. four igy extractions were performed on the egg production of both groups. the first two extractions were carried out using the yolks obtained from the eggs produced during the 4th and 5th post-vaccination week (extracts 1v and 1t) an ...19989744035
a south australian salmonella mbandaka outbreak investigation using a database to select controls.between april and june 1996, 15 persons with salmonella enterica serovar mbandaka infection were reported in south australia (population 1.6 million) compared with 12 over the previous five years. to identify a possible source for the infections a case control study was conducted.19989744205
resistance to antimicrobial agents used for animal therapy in pathogenic-, zoonotic- and indicator bacteria isolated from different food animals in denmark: a baseline study for the danish integrated antimicrobial resistance monitoring programme (danmap).this study describes the establishment and first results of a continuous surveillance system of antimicrobial resistance among bacteria isolated from pigs, cattle and broilers in denmark. the three categories of bacteria tested were: 1) indicator bacteria (escherichia coli, enterococcus faecalis, enterococcus faecium), 2) zoonotic bacteria (campylobacter coli/jejuni, salmonella enterica, yersinia enterocolitica), and 3) animal pathogens (e. coli, staphylococcus aureus, coagulase-negative staphyl ...19989744762
prevalence of the "high-pathogenicity island" of yersinia species among escherichia coli strains that are pathogenic to humans.the fyua-irp gene cluster contributes to the virulence of highly pathogenic yersinia (yersinia pestis, yersinia pseudotuberculosis, and yersinia enterocolitica 1b). the cluster encodes an iron uptake system mediated by the siderophore yersiniabactin and reveals features of a pathogenicity island. two evolutionary lineages of this "high pathogenicity island" (hpi) can be distinguished on the basis of dna sequence comparison: a y. pestis group and a y. enterocolitica group. in this study we demons ...19989453599
comparison of the abilities of different attenuated salmonella typhimurium strains to elicit humoral immune responses against a heterologous antigen.we compared the abilities of different salmonella enterica var. typhimurium (s. typhimurium) strains harboring mutations in the genes aroa, aroad, pura, ompr, htra, and cya crp to present the heterologous antigen, c fragment of tetanus toxin, to the mouse immune system. plasmid ptettac4, encoding c fragment, was transferred into the various s. typhimurium mutants, and the levels of antigen expression were found to be equivalent. after primary oral immunization of balb/c mice, all attenuated stra ...19989453634
identification of a novel core type in salmonella lipopolysaccharide. complete structural analysis of the core region of the lipopolysaccharide from salmonella enterica sv. arizonae o62.for the first time, the complete structure of a lipopolysaccharide (lps) core region from salmonella enterica has been identified that is different from the ra core type generally thought to be present in all salmonella lps. the lpss from two rough mutants and the smooth form of s. enterica sv. arizonae iiia o62, which all failed to react with an ra core type-specific monoclonal antibody and were resistant to phage fo1, were analyzed after chemical modification using monosaccharide analysis, mas ...19989461562
levels of expression and immunogenicity of attenuated salmonella enterica serovar typhimurium strains expressing escherichia coli mutant heat-labile enterotoxin.the effects of heterologous gene dosage as well as salmonella typhimurium strain variability on immune response toward both the heterologous antigen, the nontoxic mutant of the escherichia coli heat-labile enterotoxin ltk63, and the carrier salmonella strain have been analyzed. effects of a single integration into the host dna and different-copy-number episomal vectors were compared in s. typhimurium delta cya delta crp delta asd strains of two different serotypes, uk-1 and sr-11. expression of ...19989423862
a periplasmic d-alanyl-d-alanine dipeptidase in the gram-negative bacterium salmonella enterica.the vanx protein is a d-alanyl-d-alanine (d-ala-d-ala) dipeptidase essential for resistance to the glycopeptide antibiotic vancomycin. while this enzymatic activity has been typically associated with vancomycin- and teicoplainin-resistant enterococci, we now report the identification of a d-ala-d-ala dipeptidase in the gram-negative species salmonella enterica. the salmonella enzyme is only 36% identical to vanx but exhibits a similar substrate specificity: it hydrolyzes d-ala-d-ala, dl-ala-dl-p ...199910094694
phage type conversion in salmonella enterica serotype enteritidis caused by the introduction of a resistance plasmid of incompatibility group x (incx).the plasmid pog670, a 54 kb, conjugative plasmid that specifies resistance to ampicillin and kanamycin and belonging to the incompatibility group x (incx), was transferred into 10 isolates of salmonella enterica serotype enteritidis belonging to 10 different phage types (pt1, 2, 3, 4, 8, 9, 9b, 10, 11 and 13). acquisition of the plasmid by these strains did not result in the loss of any resident plasmids but resulted in phage type conversion in 8 of the 10 strains (pt1, 2, 4, 8, 9, 9b, 10 and 11 ...199910098781
molecular typing of salmonella serotype thompson strains isolated from human and animal sources.one-hundred-and-thirteen isolates of salmonella serotype thompson from diverse sources in seven countries were characterized by pvuii ribotyping and is200 fingerprinting. ten pvuii ribotypes were observed. the predominant pvuii ribotype 1 represented a major clone of world-wide distribution but was not found in australia; pvuii ribotypes 2 and 3 represented minor clones. hincii ribotyping discriminated subtypes within pvuii ribotype 1: hincii ribotype 1 was distributed widely but hincii ribotype ...199910098783
ferrioxamine-mediated iron(iii) utilization by salmonella enterica.utilization of ferrioxamines as sole sources of iron distinguishes salmonella enterica serotypes typhimurium and enteritidis from a number of related species, including escherichia coli. ferrioxamine supplements have therefore been used in preenrichment and selection media to increase the bacterial growth rate while selectivity is maintained. we characterized the determinants involved in utilization of ferrioxamines b, e, and g by s. enterica serotype typhimurium by performing siderophore cross- ...199910103258
accessory dna in the genomes of representatives of the escherichia coli reference collection.different strains of the escherichia coli reference collection (ecor) differ widely in chromosomal size. to analyze the nature of the differential gene pool carried by different strains, we have followed an approach in which random amplified polymorphic dna (rapd) was used to generate several pcr fragments. those present in some but not all the strains were screened by hybridization to assess their distribution throughout the ecor collection. thirteen fragments with various degrees of occurrence ...199910198021
detection of multidrug-resistant salmonella enterica serotype typhimurium dt104 based on a gene which confers cross-resistance to florfenicol and chloramphenicol.salmonella enterica serotype typhimurium (s. typhimurium) dt104 (dt104) first emerged as a major pathogen in europe and is characterized by its pentadrug-resistant pattern. it has also been associated with outbreaks in the united states. the organism typically carries resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline. the mechanism of chloramphenicol resistance in dt104 was determined by producing antibiotic-resistant escherichia coli host strain clones from ...199910203484
salmonella pullorum in the common pheasant (phasianus colchicus).in 1996, pullorum disease due to salmonella enterica serovar gallinarum biovar pullorum (salmonella pullorum) was diagnosed in pheasants on a gamebird rearing enterprise in south-west scotland. the gross pathology and bacteriological findings are described, as are the results of screening for s pullorum on the site in 1997. the causal organism was readily isolated from the lung, liver, yolk sac and heart blood on direct culture, but less readily from the digestive tract or by the use of selectiv ...199910204223
the medium-/long-chain fatty acyl-coa dehydrogenase (fadf) gene of salmonella typhimurium is a phase 1 starvation-stress response (ssr) locus.salmonella enterica serovar typhimurium (s. typhimurium) is an enteric pathogen that causes significant morbidity in humans and other mammals. during their life cycle, salmonellae must survive frequent exposures to a variety of environmental stresses, e.g. carbon-source (c) starvation. the starvation-stress response (ssr) of s. typhimurium encompasses the genetic and physiological realignments that occur when an essential nutrient becomes limiting for bacterial growth. the function of the ssr is ...199910206693
genetic and biochemical characterization of an operon involved in the biosynthesis of 3-deoxy-d-manno-octulosonic acid in pseudomonas aeruginosa.a pseudomonas aeruginosa serotype o5 (pao1) genomic dna fragment that was able to complement a temperature-sensitive mutation in the 3-deoxy-d-manno-octulosonic acid (kdo) 8-p synthase gene (kdsa) of salmonella enterica serovar typhimurium was cloned. nucleotide sequence analysis revealed the presence of a potential operon with the gene order pyrg, kdsa, eno. pyrg catalyzes the synthesis of the nucleotide cytidine triphosphate, while eno catalyzes the formation of phosphoenolpyruvate from phosph ...199910220877
integron- and carbenicillinase-mediated reduced susceptibility to amoxicillin-clavulanic acid in isolates of multidrug-resistant salmonella enterica serotype typhimurium dt104 from french patients.fifty-seven salmonella enterica serotype typhimurium (s. typhimurium) isolates were collected from human patients in two french hospitals, hôpital antoine béclère (clamart, france) and hôpital bicêtre (le kremlin-bicêtre, france), between 1996 and 1997. thirty of them (52 percent) were resistant to amino-, carbeni-, and ureidopenicillins, had reduced susceptibility to amoxicillin-clavulanic acid, were susceptible to cephalothin, and were resistant to sulfonamides, streptomycin, chloramphenicol, ...199910223920
clinical and veterinary isolates of salmonella enterica serovar enteritidis defective in lipopolysaccharide o-chain polymerization.twelve human and chicken isolates of salmonella enterica serovar enteritidis belonging to phage types 4, 8, 13a, and 23 were characterized for variability in lipopolysaccharide (lps) composition. isolates were differentiated into two groups, i.e., those that lacked immunoreactive o-chain, termed rough isolates, and those that had immunoreactive o-chain, termed smooth isolates. isolates within these groups could be further differentiated by lps compositional differences as detected by gel electro ...199910224019
comparative physical and genetic maps of the virulence plasmids of salmonella enterica serovars typhimurium, enteritidis, choleraesuis, and dublin.using fragment profiling, pcr, and southern hybridization, we found that salmonella enterica serovar choleraesuis harbored virulence plasmids of various sizes, whereas serovars typhimurium, enteritidis, and dublin carried a plasmid of a unique size. also, the virulence plasmid of typhimurium contained genes in the same order detected in the other three plasmids, all of which contained deletions.199910225928
cross-reactivity between six enterobacteriaceae complete lipopolysaccharide core chemotypes.to gain insight into the value of lipopolysaccharide (lps) core determinants for cross-protective immunisation the serological relationships between six complete (lps) core types from enterobacteriaceae were investigated. hyperimmune sera were raised in mice by repeated immunisation with heat-killed strains of salmonella choleraesuis (ra core type) or escherichia coli (core types r1, r2, r3, r4 and k12) and characterised for reactivity with complete and incomplete core chemotypes by elisa and im ...199910229540
revised salmonella nomenclature: designation of salmonella enterica (ex kauffmann and edwards 1952) le minor and popoff 1987 sp. nov., nom. rev. as the neotype species of the genus salmonella lignieres 1900 (approved lists 1980), rejection of the name salmonella choleraesuis (smith 1894) weldin 1927 (approved lists 1980), and conservation of the name salmonella typhi (schroeter 1886) warren and scott 1930 (approved lists 1980). request for an opinion.the request for an opinion by le minor and popoff 1987, proposing designation of 'salmonella enterica' (ex kauffman and edwards 1952) le minor and popoff 1987 as the type and only species of the genus salmonella lignieres 1900 (approved lists 1980), has not been positively decided upon by the judicial commission. however, many bacteriologists use the name 'salmonella enterica'. to avoid further confusion, it is requested to reject the name salmonella choleraesuis (smith 1894) weldin 1927 (approv ...199910319519
two arac/xyls family members can independently counteract the effect of repressing sequences upstream of the hila promoter.during infection of its hosts, salmonella enterica serovar typhimurium (s. typhimurium) enters the epithelial cells of the small intestine. this process requires a number of invasion genes encoded on salmonella pathogenicity island 1 (spi1), a 40 kb stretch of dna located near minute 63 of the s. typhimurium chromosome. expression of s. typhimurium spi1 invasion genes is activated by the transcription factor hila. hila is tightly regulated in response to many environmental conditions, including ...199910320584
typing of salmonella enterica serotype paratyphi c isolates from various countries by plasmid profiles and pulsed-field gel electrophoresis.pulsed-field gel electrophoresis (pfge) of 61 salmonella enterica serotype paratyphi c isolates from six countries gave five distinct clusters. twenty-four isolates from five countries were susceptible to 10 antimicrobials tested and gave similar restriction endonuclease digest patterns of the 38-mda plasmid. in contrast, plasmid and pfge profiles of 37 multidrug-resistant isolates from zaire were different from those from other countries.199910325380
risk factors for salmonella enterica subsp. enterica contamination in french broiler-chicken flocks at the end of the rearing period.broiler-chicken are often salmonella carriers. however, these bacteria are responsible for major food-borne human infection, in which poultry-meat products are frequently implicated. in order to prevent salmonella spread during the slaughtering process, control measures should be implemented at the farm level to reduce the prevalence before slaughtering. the objective of this study was to identify the risk factors for salmonella contamination in french commercial broiler flocks at the end of the ...199910327442
salmonella choleraesuis bacteremia in southern taiwan.within a 6-year period from january 1991 to december 1996, 19 patients with salmonella choleraesuis bacteremia were enrolled for clinical and microbiological analysis. young children, the elderly and patients with hematological malignancy (36.8%), liver cirrhosis (26.3%), systemic lupus erythematosus (10.5%), chronic renal impairment (10.5%), and peptic ulcer (10.5%) were at high risk of this infection. the ratio of male to female was 3:1. three cases (15.8%) were nosocomially acquired. fever (8 ...199910330799
genotypic characterization of human and environmental isolates of salmonella choleraesuis subspecies choleraesuis serovar infantis by pulsed-field gel electrophoresis.to determine the extent of genetic diversity of salmonella choleraesuis subspecies choleraesuis serovar infantis and whether environmental isolates were similar or identical to human isolates, a total of 110 isolates from humans, broiler samples, egg production facilities, riverwater, sewage, and chicken meat were analyzed epidemiologically by pulsed-field gel electrophoresis. while the isolates showed 35 distinct pulsed-field profiles, none had the genotype of the human isolates. one pulsed-fie ...199910338200
the roles of intrahepatic valpha14(+) nk1.1(+) t cells for liver injury induced by salmonella infection in mice.to investigate the roles of intrahepatic t cells in liver injury after salmonella infection, we examined serum alanine transaminase (alt), histopathology, and bacterial numbers in liver after infection with salmonella choleraesuis strain 31n-1 in mice genetically lacking tcralpha beta+, cd4(+), cd8(+), or nk1.1(+)t cells with c57bl/6 background. in control (+/+) mice, serum alt reached a peak level by day 7 after an intraperitoneal inoculation of 2 x 10(6) cfu salmonella choleraesuis 31n-1. in t ...199910347123
interaction of salmonella with host cells through the centisome 63 type iii secretion system.salmonella enterica engages host cells in a complex two-way biochemical interaction that results in a variety of responses from both the bacteria and the host cell. central to this interaction is the function of a type iii protein secretion system that delivers effector proteins into the host cell. during the past year we have seen major advances in our knowledge of both the bacterial determinants and the host-signal transduction pathways involved in these interactions. a coherent picture of the ...199910047557
enterobacteria in reactive arthritis: yersinia, shigella, and salmonella. 199910063518
evaluation of a multiplex pcr assay for simultaneous identification of salmonella sp., salmonella enteritidis and salmonella typhimurium from environmental swabs of poultry houses.a multiplex pcr-based assay (m-pcr) with three sets of primers was developed for the detection of all serotypes of salmonella enterica and the identification of salmonella enteritidis and salmonella typhimurium. this method was evaluated against a bacteriological method for the analysis of environmental swabs of poultry houses. samples were preenriched in phosphate-buffered peptone water for 24 h and subjected to three different protocols prior to pcr: (i) an immunomagnetic separation using dyna ...199910063640
impact of intracellular location of and antigen display by intracellular bacteria: implications for vaccine development.intracellular bacteria are primarily controlled by t-lymphocytes. the 'phagosomal' bacteria such as salmonella enterica and mycobacterium bovis bcg remain in the phagosome. these microbes primarily stimulate cd4 t-cells via antigen presentation through mhc class ii molecules. in contrast, listeria monocytogenes egresses from the phagosome into the cytoplasm by virtue of listeriolysin. this 'cytoplasmic' pathogen is controlled by cd8 t-cells through mhc class i antigen presentation. some bacteria ...199910065631
salmonella typhimurium encodes a putative iron transport system within the centisome 63 pathogenicity island.upon entry into the host, salmonella enterica strains are presumed to encounter an iron-restricted environment. consequently, these bacteria have evolved a variety of often-redundant high-affinity acquisition systems to obtain iron in this restricted environment. we have identified an iron transport system that is encoded within the centisome 63 pathogenicity island of salmonella typhimurium. the nucleotide composition of this locus is significantly different from that of the rest of this pathog ...199910085045
purification, crystallization and preliminary structural studies of dtdp-6-deoxy-d-xylo-4-hexulose 3,5-epimerase (rmlc), the third enzyme of the dtdp-l-rhamnose synthesis pathway, from salmonella enterica serovar typhimurium.l-rhamnose is an essential component of the cell wall of many pathogenic bacteria. its precusor, dtdp-l-rhamnose, is synthesized from alpha-d-glucose-1-phosphate and dttp via a pathway requiring four distinct enzymes: rmla, rmlb, rmlc and rmld. rmlc was overexpressed in escherichia coli. the recombinant protein was purified by a two-step protocol involving anion-exchange and hydrophobic chromatography. dynamic light-scattering experiments indicated that the recombinant protein is monodisperse. c ...199910089454
transduction of multiple drug resistance of salmonella enterica serovar typhimurium dt104.epidemic strain salmonella typhimurium dt104 is characterized by various multiresistance patterns. at least some of the resistance genes are organized as integrons. resistance genes of dt104 isolates can be efficiently transduced by p22-like phage es18 and by phage pdt17 which is released by all dt104 isolates so far analyzed. cotransduction tests demonstrate that the resistance genes, although not organized in a unique integron, are tightly clustered on the salmonella chromosome. the spread of ...19999919675
the spi-3 pathogenicity island of salmonella enterica.pathogenicity islands are chromosomal clusters of pathogen-specific virulence genes often found at trna loci. we have determined the molecular genetic structure of spi-3, a 17-kb pathogenicity island located at the selc trna locus of salmonella enterica serovar typhimurium. the g+c content of spi-3 (47.5%) differs from that of the salmonella genome (52%), consistent with the notion that these sequences have been horizontally acquired. spi-3 harbors 10 open reading frames organized in six transcr ...19999922266
complement activation by bacterial surface glycolipids: a study with planar bilayer membranes.planar asymmetric glycolipid/phospholipid bilayer membranes were used as a reconstitution model of the lipid matrix of the outer membrane of gram-negative bacteria to study complement (c) activation by various bacterial surface glycolipids with the aim of defining the c activation pathway. as glycolipids the lipopolysaccharides of salmonella enterica serovar minnesota r mutant strains r595 (re lps) and r4 (rd2 lps), pentaacyl lipid a from the lps of the escherichia coli re mutant f515, and glyco ...19999929374
the virulence plasmid of salmonella typhimurium is self-transmissible.most isolates of salmonella enterica serovar typhimurium contain a 90-kb virulence plasmid. this plasmid is reported to be mobilizable but nonconjugative. however, we have determined that the virulence plasmid of strains lt2, 14028, and sr-11 is indeed self-transmissible. the plasmid of strain sl1344 is not. optimal conjugation frequency requires filter matings on m9 minimal glucose plates with a recipient strain lacking the virulence plasmid. these conditions result in a frequency of 2.9 x 10(- ...19999973370
mhc class ii-dependent nk1.1+ gammadelta t cells are induced in mice by salmonella infection.we observed the emergence of a novel population of gammadelta t cells expressing nk1.1 ag in the peritoneal cavity of mice infected with salmonella choleraesuis. the nk1.1+gammadelta t cells accounted for approximately 20% of all gammadelta t cells emerging in the peritoneal cavity of c57bl/6 mice and expressed preferentially rearranged vgamma4-jgamma1 and vdelta6.3-ddelta1-ddelta2-jdelta1 genes with n diversity. the gammadelta t cells proliferated vigorously in response to pha-treated spleen ce ...19999973415
multinational outbreak of salmonella enterica serotype newport infections due to contaminated alfalfa sprouts.in december 1995, reported salmonella enterica serotype newport (sn) infections increased sharply in oregon and british columbia but not elsewhere in north america. similar unexplained increases had been noted in 6 other states in the fall of 1995.19999917119
increasing incidence and comparison of nalidixic acid-resistant salmonella enterica subsp. enterica serotype typhimurium isolates from humans and animals.we determined the resistance to quinolone of 309 salmonella enterica subsp. enterica serotype typhimurium strains isolated from humans and animals (cattle, pigs, or poultry) in 1995 or 1996. nalidixic acid resistance increased from 8.5% in 1995 to 18.6% in 1996. the highest resistance levels correlated with a mutation at ser-83 (or asp-82). all strains remained ciprofloxacin susceptible. human and animal isolates were compared by pulsed-field gel electrophoresis, and the banding patterns of the ...19999854111
interaction of nk lysin, a peptide produced by cytolytic lymphocytes, with endotoxin.nk lysin is a 9-kda polypeptide that was originally isolated from porcine intestinal tissue based on its antibacterial activity. it is produced by cytolytic lymphocytes and is cytolytic against a number of different types of tumor cells. here we report the binding of nk lysin to lipopolysaccharide (lps) and its anti-lps activity. nk lysin binds to matrix-coated lps from escherichia coli, pseudomonas aeruginosa, and different strains of salmonella enterica. lipid a and polymyxin b inhibited the b ...19999864216
[yet, the name salmonella choleraesuis does not be used]. 199910356955
molecular cloning of an immunogenic and acid-induced isocitrate dehydrogenase gene from coxiella burnetii.the coxiella burnetii icd gene encoding an immunogenic dimeric nadp(+)-dependent isocitrate dehydrogenase (idh) was cloned by screening a c. burnetii genomic library with a human positive serum and sequenced. the predicted gene product consists of 427 amino acids (m(r) = 46,600) and showed high identity to the idhs of escherichia coli (74%), salmonella enterica (73%) and idh-i of vibrio sp. (71%). the cloned gene complemented an icd-defective e. coli mutant producing a recombinant idh that had t ...199910361714
salmonella enteritidis phage types 1 and 4: pheno- and genotypic epidemiology of recent outbreaks in finland.in the 1990s, salmonella enterica subsp. enterica serovar enteritidis has caused 15 outbreaks in finland; 12 of them were caused by phage type 1 (pt1) and pt4. thus far, there has been no clear evidence as to the source of these salmonella enteritidis pt1 and pt4 strains, so it was necessary to try to characterize them further. salmonella enteritidis pt1 (n = 57) and pt4 (n = 43) isolates from different sources were analyzed by genomic pulsed-field gel electrophoresis (pfge), plasmid profiling, ...199910364582
high efficiency gene replacement in salmonella enteritidis: chimeric fimbrins containing a t-cell epitope from leishmania major.a simple, high frequency chromosomal gene replacement method of general utility was developed for salmonella enteritidis. this system uses an unstable, imperfectly segregating, temperature-sensitive replicon, phsg415, as a carrier of the recombinant gene of interest. it also allows for site-specific replacement of chromosomal genes without the need for antibiotic resistance markers in the recombinant genes or the use of specific bacterial strains. this strategy was used to replace the chromosoma ...199910367948
immunization of mice with live oral vaccine based on a salmonella enterica (sv typhimurium) aroa strain expressing the escherichia coli o111 o antigen.shiga toxin-producing escherichia coli strains of serogroup o111 are the most frequently isolated non-o157 strains causing outbreaks of gastroenteritis with haemolytic uraemic syndrome (hus). o antigen is a major antigen in gram-negative bacteria, and it has been shown that o111 is a protective antigen. attenuated salmonella enterica sv typhimurium aroa strain stm-1 was used as a live carrier to express the e. coli o111 o antigen. mice immunized intraperitoneally produced serum immunoglobulin g, ...199910371709
resistance of escherichia coli and salmonella against nisin and curvacin a.we have determined the effects of the following factors on the resistance of gram-negative bacteria against nisin and curvacin a: (i) chemotype of the lipopolysaccharide (lps), (ii) addition of agents permeabilizing the outer membrane, (iii) the fatty acid supply of the growth medium, and (iv) the adaptation to acid and salt stress. bacteriocin activity was determined against growing and resting cells as well as protoplasts. all smooth strains of escherichia coli and salmonella enterica serovar ...199910375133
resistance of salmonella and campylobacter species to antimicrobial agents. 199910385026
structural predictions of agfa, the insoluble fimbrial subunit of salmonella thin aggregative fimbriae.the unusually stable and multifunctional, thin aggregative fimbriae common to all salmonella spp. are principally polymers of the fimbrin subunit, agfa. agfa of salmonella enteritidis consists of two domains: a protease-sensitive, 22 amino acid residue n-terminal region and a protease-resistant, 109 residue c-terminal core. the unusual amino acid sequence of the agfa core region comprises two-, five- and tenfold internal sequence homology patterns reflected in five conserved, 18-residue tandem r ...199910395827
comparative study on the in vitro antibacterial activity of australian tea tree oil, cajuput oil, niaouli oil, manuka oil, kanuka oil, and eucalyptus oil.to compare the antibacterial activity of the australian tea tree oil (tto) with various other medicinally and commercially important essential myrtaceous oils (cajuput oil, niaouli oil, kanuka oil, manuka oil, and eucalyptus oil) the essential oils were first analysed by gc-ms and then tested against various bacteria using a broth microdilution method. the highest activity was obtained by tto, with mic values of 0.25% for enterobacter aerogenes, escherichia coli, klebsiella pneumoniae, proteus m ...199910399193
salmonella enterica serotype dublin infection: an emerging infectious disease for the northeastern united states.salmonella enterica subspecies enterica serotype dublin (s. enterica dublin) emerged for the first time in new york, pennsylvania, and ohio in 1988. since that time this host-adapted serotype has spread throughout the veal- and dairy beef-raising operations in the region; very few dairy farms have experienced clinical s. enterica dublin infections. this study details the epidemiology of the outbreaks in cattle. during the period 1988 through 1995, nine new york and four pennsylvania counties hav ...199910405378
molecular typing of multiple-antibiotic-resistant salmonella enterica serovar typhi from vietnam: application to acute and relapse cases of typhoid fever.the rate of multiple-antibiotic resistance is increasing among salmonella enterica serovar typhi strains in southeast asia. pulsed-field gel electrophoresis (pfge) and other typing methods were used to analyze drug-resistant and -susceptible organisms isolated from patients with typhoid fever in several districts in southern vietnam. multiple pfge and phage typing patterns were detected, although individual patients were infected with strains of a single type. the pfge patterns were stable when ...199910405386
a salmonella virulence protein that inhibits cellular trafficking.salmonella enterica requires a type iii secretion system, designated spi/ssa, to survive and proliferate within macrophages. the spi/ssa system is encoded within the spi-2 pathogenicity island and appears to function intracellularly. here, we establish that the spi-2-encoded spic protein is exported by the spi/ssa type iii secretion system into the host cell cytosol where it interferes with intracellular trafficking. in j774 macrophages, wild-type salmonella inhibited fusion of salmonella-contai ...199910406797
the selc-associated shi-2 pathogenicity island of shigella flexneri.pathogenicity islands are chromosomal gene clusters, often located adjacent to trna genes, that encode virulence factors present in pathogenic organisms but absent or sporadically found in related non-pathogenic species. the selc trna locus is the site of integration of different pathogenicity islands in uropathogenic escherichia coli, enterohaemorrhagic e. coli and salmonella enterica. we show here that the selc locus of shigella flexneri, the aetiological agent of bacterial dysentery, also con ...199910411725
antibody responses against flagellin in mice orally immunized with attenuated salmonella vaccine strains.salmonella fiagellin has been repeatedly used as a carrier for heterologous peptide epitopes either as a parenterally delivered purified antigen or as a parenterally/orally-administered, flagellated, live, attenuated vaccine. nonetheless, the ability to induce specific antibody responses against the flagellin moiety, fused or not with heterologous peptide, has not usually been reported in mice orally inoculated with a live, attenuated, flagellated salmonella strain. in this work we evaluated the ...199910415171
differential regulation of salmonella typhimurium type iii secreted proteins by pathogenicity island 1 (spi-1)-encoded transcriptional activators invf and hila.salmonella enterica encodes a type iii protein secretion system within a pathogenicity island (spi-1) that is located at centisome 63 of its chromosome. this system is required for the ability of these bacteria to stimulate cellular responses that are essential for their pathogenicity. expression of components and substrates of this system is subject to complex regulatory mechanisms. these mechanisms involve the function of hila and invf, two transcriptional regulatory proteins encoded within sp ...199910417179
multiple insertions of fimbrial operons correlate with the evolution of salmonella serovars responsible for human disease.on centisome 7, salmonella spp. contain a large region not present in the corresponding region of escherichia coli. this region is flanked by sequences with significant homology to the e. coli trna gene aspv and the hypothetical e. coli open reading frame yafv. the locus consists of a mosaic of differentially acquired inserts forming a dynamic cs7 region of horizontally transferred inserts. salmonella enterica subspecies i, responsible for most salmonella infections in warm-blooded animals, carr ...199910417651
plasmid-encoded tetracycline resistance in salmonella enterica subsp. enterica serovars choleraesuis and typhimurium: identification of complete and truncated tn1721 elements.during routine screening of salmonella enterica subsp., s. enterica isolates of animal origin for plasmid-encoded tetracycline resistance, two tetracycline resistance plasmids, the 50 kbp plasmid pgft3 of salmonella choleraesuis and the 9.5 kbp plasmid pgft4 of salmonella typhimurium var. copenhagen dt002, were detected. the respective tetracycline resistance genes (tet) were identified by hybridization and pcr analysis to belong to hybridization class a. conjugation experiments identified plasm ...199910418136
characterization of is1541-like elements in yersinia enterocolitica and yersinia pseudotuberculosis.we characterized yersinia enterocolitica and yersinia pseudotuberculosis insertion sequences related to insertion sequence 1541, recently identified in yersinia pestis. for each of the two species, two insertion sequence copies were cloned and sequenced. genetic elements from y. pseudotuberculosis were almost identical to insertion sequence 1541, whereas these from y. enterocolitica were less related. phylogenetic analysis of the putative transposases encoded by insertion sequences from the thre ...199910418150
salmonella level of danish swine herds based on serological examination of meat-juice samples and salmonella occurrence measured by bacteriological follow-up.analyses of data collected in the danish salmonella control program in swine herds were conducted to assess the association between bacteriological and serological findings (including the degree to which changing serological status over time modulated the relationship) and to assess the degree to which type of swine operation and age group affected the relationship between bacteriological and serological findings. although serological status was significantly associated with bacteriological prev ...199910423781
use of single-strand conformation polymorphism analysis to examine the variability of the rpos sequence in environmental isolates of salmonellae.the natural environment places its resident microflora under stress, which may often result in adaptation by the microflora in order to increase the probability of survival. one such mechanism that has been postulated involves rpos, which encodes a sigma factor that is known to enhance survival upon exposure to stress. the present work aimed to examine the genetic variability of rpos in a selection of salmonella enterica subspecies environmental isolates with an automated single-strand conformat ...199910427052
risk factors associated with salmonella enterica serovar typhimurium infection in danish broiler flocks.a retrospective longitudinal study was conducted to identify risk factors associated with salmonella enterica serovar typhimurium (s. typhimurium) infection in danish broiler flocks. the data included all broiler flocks slaughtered in 1995, and the epidemiological unit was the individual broiler flock. the s. typhimurium status was determined by microbiological examination of 60 fresh fecal samples. this procedure should detect an infected flock with a probability above 95%, if the prevalence is ...199910438128
antimicrobial activity of essential oils and other plant extracts.the antimicrobial activity of plant oils and extracts has been recognized for many years. however, few investigations have compared large numbers of oils and extracts using methods that are directly comparable. in the present study, 52 plant oils and extracts were investigated for activity against acinetobacter baumanii, aeromonas veronii biogroup sobria, candida albicans, enterococcus faecalis, escherichia col, klebsiella pneumoniae, pseudomonas aeruginosa, salmonella enterica subsp. enterica s ...199910438227
anti-immune trick unveiled in salmonella. 199910438287
regulatory role of peritoneal nk1.1+ alpha beta t cells in il-12 production during salmonella infection.nk1.1+ alpha beta t cells emerge in the peritoneal cavity after an i.p. infection with salmonella choleraesuis in mice. to elucidate the role of the nk1.1+ alpha beta t cells during murine salmonellosis, mice lacking nk1.1+ alpha beta t cells by disruption of tcr beta (tcr beta-/-), beta 2m (beta 2m-/-), or j alpha 281 (j alpha 281-/-) gene were i.p. inoculated with s. choleraesuis. the peritoneal exudate t cells in wild type (wt) mice on day 3 after infection produced il-4 upon tcr alpha beta s ...199910438944
the role of intrahepatic gammadelta-t cells for liver injury induced by salmonella infection in mouse.liver injury was induced after infection with salmonella choleraesuis 31n-1. in t-cell receptor-delta knockout mice, serum alanine transferase level was significantly decreased in comparison with normal control mice after salmonella infection. on the contrary, in vivo administration of anti-gammadelta t-cell receptor monoclonal antibody (uc7-13d5) to stimulate gammadelta-t cells in infected mice significantly increased serum alanine transferase level but decreased bacterial growth compared with ...199910449252
the role of flagella, but not fimbriae, in the adherence of salmonella enterica serotype enteritidis to chick gut explant.to gain an understanding of the role of fimbriae and flagella in the adherence and colonisation of salmonella enterica serotype enteritidis in chickens, an in-vitro gut adherence assay was developed and used to assess the adherence of a wild-type enteritidis strain and isogenic non-fimbriate and non-flagellate mutant strains. enteritidis strain s1400/94, a clinical isolate virulent in chickens, was shown to possess genes which encoded type 1, sef14, sef17, plasmid-encoded and long polar fimbriae ...199910451001
characterization of dtdp-4-dehydrorhamnose 3,5-epimerase and dtdp-4-dehydrorhamnose reductase, required for dtdp-l-rhamnose biosynthesis in salmonella enterica serovar typhimurium lt2.the thymidine diphosphate-l-rhamnose biosynthesis pathway is required for assembly of surface glycoconjugates in a growing list of bacterial pathogens, making this pathway a potential therapeutic target. however, the terminal reactions have not been characterized. to complete assignment of the reactions, the four enzymes (rmlabcd) that constitute the pathway in salmonella enterica serovar typhimurium lt2 were overexpressed. the purified rmlc and d enzymes together catalyze the terminal two steps ...199910455186
attenuation and immunogenicity of deltacya deltacrp derivatives of salmonella choleraesuis in pigs.six different isogenic deltacya deltacrp derivatives of a strain of salmonella choleraesuis var. kunzendorf-chi3246 virulent for pigs were constructed by transposon-mediated deletion mutagenesis. these strains were evaluated for virulence and ability to elicit a protective immune response in young weaned pigs after oral administration and were compared to a commercially available vaccine which lacks the 50-kb virulence plasmid (vpl(-)). these derivatives were deltacya deltacrp vpl(+), deltacya d ...199910456909
virulence of salmonella enterica serotype enteritidis aflagellate and afimbriate mutants in a day-old chick model.certain fimbriae and the flagellae of salmonella enterica serovar typhimurium have been shown to contribute to attachment and invasion of gut epithelium in the murine typhoid infection model and to contribute to pathogenesis in the chick. however, little is known of the role these organelles play in enteritidis poultry infections and, to study this, day-old chicks were dosed orally in separate experiments with defined multiply afimbriate and/or aflagellate mutant strains of enteritidis. the colo ...199910459641
discrimination between endemic and feedborne salmonella infantis infection in cattle by molecular typing.salmonella enterica serovar infantis is endemic in finnish cattle. feed contaminated with s. infantis was distributed to cattle farms in may 1995. following increased sampling, s. infantis was detected on 242 farms in 1995. molecular typing was used to differentiate the farms that were infected by the feed-related infantis from those infected by other endemic strains. twenty-three isolates from feed in 1995 and 413 from cattle (72 from 19924, 324 from 1995, 17 from 1996-7) were analysed. the fee ...199910459655
membrane vesicles derived from pseudomonas aeruginosa and shigella flexneri can be integrated into the surfaces of other gram-negative bacteria.incubation of intact salmonella typhi ty21a, salmonella enterica serovar typhimurium (salmonella typhimurium) aroa or escherichia coli dh5 alpha with membrane vesicles (mvs) derived from either shigella flexneri m90t or pseudomonas aeruginosa dsp89 resulted in a significant incorporation of vesicle antigens into the outer membrane of the bacteria; each recipient strain possessed a surface mosaic of new shigella and pseudomonas antigens intermixed with the native antigens of the salmonella or esc ...199910463171
incidence of quinolone resistance over the period 1986 to 1998 in veterinary salmonella isolates from germany.a total of 24,591 nonhuman salmonella strains isolated in germany between 1986 and 1998 were examined for their resistance to nalidixic acid by an agar diffusion method. the rate of resistance (inhibition zone, </=13 mm) ranged from 0.2% in 1986 to a peak of 14. 8% in 1990. between 1991 and 1998 the mics for nalidixic acid-resistant strains ranged from more than 256 microg/ml for nalidixic acid to between 0.25 and 128 microg/ml for enrofloxacin. in the early 1990s a particularly high incidence o ...199910471579
an increase in sporadic and outbreak-associated salmonella enteritidis infections in wisconsin: the role of eggs.in wisconsin, reported salmonella enterica serotype enteritidis (se) infections during 1997 more than doubled compared with the previous 9 years. a case-control study was conducted to determine risk factors for sporadic infections, and results of outbreak investigations were reviewed. eating raw eggs (matched odds ratio [mor]=14.5; 95% confidence interval [ci], 1.7-591.6), eating raw or undercooked eggs (mor=5.8; 95% ci, 1.3-28.0), eating any eggs (mor=4.2; 95% ci, 1.2-16.2), and dining at a res ...199910479150
molecular characterization of the pmra regulon.the two-component system pmra/pmrb of salmonella enterica controls expression of several loci including those mediating modifications in the lipopolysaccharide that result in polymyxin resistance. to gain insight in the regulation of polymyxin resistance, we mapped the transcription start sites of the pmra-regulated genes pmrc, pmrg, pbgpe, and ugd and identified a conserved sequence in the promoter region of the first three genes. his-tagged pmra protein could gel shift dna fragments containing ...199910480935
cost-effective methods for isolation of salmonella enterica in the clinical laboratory.data from 8,717 fecal specimens indicate that primary inoculation of xylose lysine deoxycholate (xld) agar may enhance the speed, but not the sensitivity, of isolation of salmonella enterica over that achieved with selenite enrichment only. plating of selenite broth onto both brilliant green and xld agar offers no advantage over plating onto xld alone.199910488209
emergence and spread of an atypical salmonella enterica subsp. enterica serotype 4,5,12:i:- strain in spain. 199910488227
pulsed field gel electrophoresis identifies an outbreak of salmonella enterica serotype montevideo infection associated with a supermarket hot food outlet.in february 1996 salmonella enterica serotype montevideo infection in a patient in the north tyneside area was attributed to consumption of cooked chicken bought from a supermarket hot food outlet. isolates from the patient, leftover food, and environmental samples were indistinguishable by pulsed field gel electrophoresis (pfge). pfge also demonstrated that an outbreak of infection with s. montevideo associated with the hot food outlet had occurred in late 1995 and early 1996. this study shows ...199910491878
endogenous il-15 might be responsible for early protection by natural killer cells against infection with an avirulent strain of salmonella choleraesuis in mice.interleukin (il)-15 is a novel cytokine with growth factor activity for t cells, b cells, and natural killer cells (nk cells). we investigated the role of il-15 in the host defense against infection with avirulent salmonella choleraesuis strain 31n-1 cured of 50-kb virulent plasmid. il-15 was abundantly expressed at transcription and protein levels in macrophages infected with s. choleraesuis 31n-1. the number of nk cells in the infected sites was increased during the course of infection coincid ...199910496307
use of in vivo-regulated promoters to deliver antigens from attenuated salmonella enterica var. typhimurium.this study describes the construction and analysis of three in vivo-inducible promoter expression plasmids, containing pnirb, ppagc, and pkatg, for the delivery of foreign antigens in the deltaaroad mutant of salmonella enterica var. typhimurium (hereafter referred to as s. typhimurium). the reporter genes encoding beta-galactosidase and firefly luciferase were used to assess the comparative levels of promoter activity in s. typhimurium in vitro in response to different induction stimuli and in ...199910496887
the propanediol utilization (pdu) operon of salmonella enterica serovar typhimurium lt2 includes genes necessary for formation of polyhedral organelles involved in coenzyme b(12)-dependent 1, 2-propanediol degradation.the propanediol utilization (pdu) operon of salmonella enterica serovar typhimurium lt2 contains genes needed for the coenzyme b(12)-dependent catabolism of 1,2-propanediol. here the completed dna sequence of the pdu operon is presented. analyses of previously unpublished pdu dna sequence substantiated previous studies indicating that the pdu operon was acquired by horizontal gene transfer and allowed the identification of 16 hypothetical genes. this brings the total number of genes in the pdu o ...199910498708
salmonella enterica serovar. typhimurium phage type dt104 and other multi-drug resistant strains in japan. 199910507998
the outer membrane of gram-negative bacteria inhibits antibacterial activity of brochocin-c.brochocin-c is a two-peptide bacteriocin produced by brochothrix campestris atcc 43754 that has a broad activity spectrum comparable to that of nisin. brochocin-c has an inhibitory effect on edta-treated gram-negative bacteria, salmonella enterica serovar typhimurium lipopolysaccharide mutants, and spheroplasts of typhimurium strains lt2 and sl3600. brochocin-c treatment of cells and spheroplasts of strains of lt2 and sl3600 resulted in hydrolysis of atp. the outer membrane of gram-negative bact ...199910508055
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