Publications

TitleAbstractYear
Filter
PMID
Filter
phage typing of campylobacter jejuni and campylobacter coli and its use as an adjunct to serotyping.campylobacter is the most commonly reported cause of gastro-intestinal infection in england and wales, with over 50,000 reported cases in 1997. the majority of human campylobacter isolates in england and wales are c. jejuni (c. 90%) with most of the remainder being c. coli. we describe the use of phage typing as an extension to serotyping for more detailed characterization within these two species. the scheme was piloted during a study of 2407 c. jejuni and 182 c. coli strains isolated in wales ...199910487641
ciprofloxacin resistance in campylobacter jejuni isolates: detection of gyra resistance mutations by mismatch amplification mutation assay pcr and dna sequence analysis.the gyra quinolone resistance determining region was sequenced from 13 ciprofloxacin-resistant and 20 ciprofloxacin-susceptible campylobacter jejuni isolates. all isolates resistant to ciprofloxacin had thr-86-to-ile mutations, a mutation frequently associated with the acquisition of resistance to fluoroquinolones. a mismatch amplification mutation assay (mama) pcr protocol was developed that detects this gyra mutation in quinolone-resistant isolates. the mama pcr provides a means for routine de ...199910488192
specific pcr identification and differentiation of the thermophilic campylobacters, campylobacter jejuni, c. coli, c. lari, and c. upsaliensis.a sensitive pcr assay that detects the thermophilic campylobacters c. jejuni, c. coli, c. lari, and c. upsaliensis is reported. furthermore, by digestion of the pcr products with two restriction enzymes, species differentiation was demonstrated. thus, the present method has the potential to be used for both detection and identification of thermophilic campylobacter species.199910488210
the absence of cecal colonization of chicks by a mutant of campylobacter jejuni not expressing bacterial fibronectin-binding protein.campylobacter jejuni is a common cause of human gastrointestinal illness throughout the world. infections with c. jejuni and campylobacter coli are frequently acquired by eating undercooked chicken. the ability of c. jejuni to become established in the gastrointestinal tract of chickens is believed to involve binding of the bacterium to the gastrointestinal surface. a 37-kd outer membrane protein, termed cadf, has been described that facilitates the binding of campylobacter to fibronectin. this ...199910494431
phase variation in helicobacter pylori lipopolysaccharide due to changes in the lengths of poly(c) tracts in alpha3-fucosyltransferase genes.the lipopolysaccharide (lps) of helicobacter pylori expresses the lewis x (lex) and/or ley antigen. we have shown previously that h. pylori lps displays phase variation whereby an lex-positive strain yields variants with different lps serotypes, for example, lex plus ley or nonfucosylated polylactosamine. h. pylori has two alpha3-fucosyltransferase genes that both contain poly(c) tracts. we now demonstrate that these tracts can shorten or lengthen randomly, which results in reversible frameshift ...199910496917
viability and dna maintenance in nonculturable spiral campylobacter jejuni cells after long-term exposure to low temperatures.survival of campylobacter jejuni at 4 and 20 degrees c was investigated by using cellular integrity, respiratory activity, two-dimensional (2d) protein profile, and intact dna content as indicators of potential viability of nonculturable cells. intact dna content after 116 days, along with cellular integrity and respiring cells, was detected for up to 7 months at 4 degrees c by pulsed-field gel electrophoresis. most changes in 2d protein profiles involved up- or down-regulation.199910508106
campylobacter jejuni contains two fur homologs: characterization of iron-responsive regulation of peroxide stress defense genes by the perr repressor.expression of the peroxide stress genes alkyl hydroperoxide reductase (ahpc) and catalase (kata) of the microaerophile campylobacter jejuni is repressed by iron. whereas iron repression in gram-negative bacteria is usually carried out by the fur protein, previous work showed that this is not the case in c. jejuni, as these genes are still iron repressed in a c. jejuni fur mutant. an open reading frame encoding a fur homolog (designated perr for "peroxide stress regulator") was identified in the ...199910515927
routine identification of campylobacter jejuni and campylobacter coli from human stool samples.correct identification of campylobacter jejuni and campylobacter coli isolates to the species or subspecies level is a cumbersome but nevertheless important task for a routine diagnostic laboratory. the widely used biochemical tests might be often misleading while more sophisticated phenotypic or genotypic methods are not generally available. this investigation was performed to assess the performance of common biochemical identification in comparison with species-specific pcr and gas liquid chro ...199910518720
evaluation of a truncated recombinant flagellin subunit vaccine against campylobacter jejuni.a recombinant protein comprising the maltose-binding protein (mbp) of escherichia coli fused to amino acids 5 to 337 of the flaa flagellin of campylobacter coli vc167 was evaluated for immunogenicity and protective efficacy against challenge by a heterologous strain of campylobacter, campylobacter jejuni 81-176, in two murine models. the sequence of the flaa gene of strain 81-176 revealed a predicted protein which was 98.1% similar to that of vc167 flaa over the region expressed in the fusion pr ...199910531231
molecular characterization of the locus encoding biosynthesis of the lipopolysaccharide o antigen of escherichia coli serotype o113.shiga toxigenic escherichia coli (stec) strains are a diverse group of organisms capable of causing severe gastrointestinal disease in humans. within the stec family, eae-positive stec strains, particularly those belonging to serogroups o157 and o111, appear to have greater virulence for humans. however, in spite of being eae negative, stec strains belonging to serogroup o113 have frequently been associated with cases of severe stec disease, including hemolytic-uremic syndrome (hus). western blo ...199910531250
recovery in embryonated eggs of viable but nonculturable campylobacter jejuni cells and maintenance of ability to adhere to hela cells after resuscitation.the existence of a viable but nonculturable (vbnc) state has been described for campylobacter jejuni as it had been for a number pathogenic bacteria. three c. jejuni human isolates were suspended in surface water and subsequently entered the vbnc state. after starvation for 30 days, vbnc cells were inoculated in the yolk sacs of embryonated eggs. culturable cells were detected in a large proportion of the embryonated eggs inoculated with vbnc c. jejuni cells. recovered cells kept their adhesion ...199910543837
large-scale survey of campylobacter species in human gastroenteritis by pcr and pcr-enzyme-linked immunosorbent assay.a pcr-based study of the incidence of enteropathogenic campylobacter infection in humans was done on the basis of a detection and identification algorithm consisting of screening pcrs and species identification by pcr-enzyme-linked immunosorbent assay. this was applied to dna extracted from 3,738 fecal samples from patients with sporadic cases of acute gastroenteritis, submitted by seven regional public health laboratories in england and wales over a 2-year period. the sending laboratories had c ...199910565897
rapid identification of campylobacter, arcobacter, and helicobacter isolates by pcr-restriction fragment length polymorphism analysis of the 16s rrna gene.a rapid two-step identification scheme based on pcr-restriction fragment length polymorphism (pcr-rflp) analysis of the 16s rrna gene was developed in order to differentiate isolates belonging to the campylobacter, arcobacter, and helicobacter genera. for 158 isolates (26 reference cultures and 132 clinical isolates), specific rflp patterns were obtained and species were successfully identified by this assay.199910565952
helicobacter pylori and neutrophils: sialic acid-dependent binding to various isolated glycoconjugates.helicobacter pylori has been shown to agglutinate erythrocytes in a sialic acid-dependent manner. however, very few studies have examined relevant target cells in the human stomach. neutrophils are required for the onset of gastritis, and the inflammatory reaction may be induced on contact between bacteria and neutrophils. in the present work, glycolipids and glycoproteins were isolated from neutrophils and were studied for binding by overlay with radiolabeled bacteria on thin-layer chromatogram ...199910569742
localized reversible frameshift mutation in the flha gene confers phase variability to flagellin gene expression in campylobacter coli.phase variation of flagellin gene expression in campylobacter coli ua585 was correlated with high-frequency, reversible insertion and deletion frameshift mutations in a short homopolymeric tract of thymine residues located in the n-terminal coding region of the flha gene. mutation-based phase variation in flha may generate functional diversity in the host and environment.200010613882
genotyping of campylobacter spp. 200010618195
isolation and characterization of campylobacter jejuni subsp. jejuni from macaroni penguins (eudyptes chrysolophus) in the subantarctic region.on bird island, south georgia, albatrosses (n = 140), penguins (n = 100), and fur seals (n = 206) were sampled for campylobacter jejuni. c. jejuni subsp. jejuni was recovered from three macaroni penguins (eudyptes chrysolophus). these isolates, the first reported for the subantarctic region, showed low genetic diversity and high similarity to northern hemisphere c. jejuni isolates, possibly suggesting recent introduction to the area.200010618265
prevalence of campylobacter, arcobacter, helicobacter, and sutterella spp. in human fecal samples as estimated by a reevaluation of isolation methods for campylobacters.the aims of this study were to investigate the prevalence of campylobacteria including campylobacter jejuni subsp. jejuni (c. jejuni) and campylobacter coli in human clinical samples and in samples from healthy individuals and to reevaluate the efficacies of conventional selective methods for isolation of campylobacter spp. two charcoal-based selective media, modified charcoal cefoperazone deoxycholate agar (mccda) and cefoperazone-amphotericin-teicoplanin (cat) agar, were compared with skirrow' ...200010618103
a multifunctional atp-binding cassette transporter system from vibrio cholerae transports vibriobactin and enterobactin.vibrio cholerae uses the catechol siderophore vibriobactin for iron transport under iron-limiting conditions. we have identified genes for vibriobactin transport and mapped them within the vibriobactin biosynthetic gene cluster. within this genetic region we have identified four genes, viup, viud, viug and viuc, whose protein products have homology to the periplasmic binding protein, the two integral cytoplasmic membrane proteins, and the atpase component, respectively, of other iron transport s ...199910601218
virulent strains of helicobacter pylori demonstrate delayed phagocytosis and stimulate homotypic phagosome fusion in macrophages.helicobacter pylori colonizes the gastric epithelium of approximately 50% of the world's population and plays a causative role in the development of gastric and duodenal ulcers. h. pylori is phagocytosed by mononuclear phagocytes, but the internalized bacteria are not killed and the reasons for this host defense defect are unclear. we now show using immunofluorescence and electron microscopy that h. pylori employs an unusual mechanism to avoid phagocytic killing: delayed entry followed by homoty ...200010620610
cytolethal distending toxin sequence and activity in the enterohepatic pathogen helicobacter hepaticus.little is known about the molecular pathogenesis of hepatitis and enterocolitis caused by enterohepatic helicobacter species. sonicates of the murine pathogen helicobacter hepaticus were found to cause progressive cell distension, accumulation of filamentous actin, and g(2)/m cell cycle arrest in hela cell monolayers. the genes encoding this cytotoxic activity were cloned from h. hepaticus. three open reading frames with closest homology to cdta, cdtb, and cdtc from campylobacter jejuni were ide ...200010603386
drug resistance in campylobacter jejuni, c coli, and c lari isolated from humans in north west england and wales, 1997.to test the sensitivity of strains of campylobacter species isolated from humans in england and wales against a range of antimicrobial agents for the purpose of monitoring therapeutic efficacy and as an epidemiological marker.199910690169
antibiotic resistance in campylobacter strains isolated from animals, foods, and humans in spain in 1997-1998.colonization by campylobacter strains was investigated in human, broiler, and pig fecal samples from 1997-1998, as well as in foods of animal origin, and antibiotic susceptibility testing was carried out for these strains. campylobacter strains were isolated in the foods of animal origin (55 of 101 samples; 54.4%), intestinal samples from broilers (85 of 105; 81%), and pigs (40 of 45; 88.9%). a total of 641 campylobacter strains were isolated from 8,636 human fecal samples of clinical origin (7. ...200010639348
improved repetitive-element pcr fingerprinting of salmonella enterica with the use of extremely elevated annealing temperatures.modified thermal cycling conditions were explored in an effort to improve the reproducibility and resolving power of repetitive-element pcr (rep-pcr) fingerprinting. assay performance was rigorously evaluated under standard and modified cycling conditions, using as a test set 12 strains putatively representing 12 serovars of salmonella enterica. for all three fingerprint types (eric2, boxa1r, and composite fingerprints), the use of extremely elevated annealing temperatures plus an initial "touch ...200010702502
serum amyloid p component bound to gram-negative bacteria prevents lipopolysaccharide-mediated classical pathway complement activation.although serum amyloid p component (sap) is known to bind many ligands, its biological function is not yet clear. recently, it was demonstrated that sap binds to lipopolysaccharide (lps). in the present study, sap was shown to bind to gram-negative bacteria expressing short types of lps or lipo-oligosaccharide (los), such as salmonella enterica serovar copenhagen re and escherichia coli j5, and also to clinical isolates of haemophilus influenzae. it was hypothesized that sap binds to the bacteri ...200010722560
flagellin gene polymorphism analysis of campylobacter compared with antigen serotyping.flagellin gene sequence polymorphisms were used to discriminate amongst 53 strains of campylobacter jejuni and c. coli. the campylobacter strains were made up of forty-three strains of campylobacter jejuni and 10 strains of campylobacter coli. the results were analysed in relation to penner serotyping. twenty dna pcr-rflp patterns (genotypes) were identified by analysis of dde i fragment length polymorphisms in flagellin gene (fla a and fla b) polymerase chain reaction (pcr) products. flagellin ...199910627993
chronic atrophic gastritis in scid mice experimentally infected with campylobacter fetus.campylobacter fetus is a cause of enteritis and invasive extraintestinal disease in humans. in order to develop an animal model of c. fetus infection, outbred icr scid mice were orally challenged with a clinical isolate of c. fetus. the stomachs of scid mice were heavily colonized with c. fetus, and colonization was associated with the development of chronic atrophic gastritis. this lesion was characterized by an inflammatory infiltrate of granulocytes and macrophages that over time resulted in ...200010722608
lipopolysaccharides of a campylobacter coli isolate from a patient with guillain-barré syndrome display ganglioside mimicry.campylobacter coli was isolated from a patient with severe, axonal type guillain-barré syndrome (gbs). the patient's serum was tested by elisa for glycolipid antibodies and showed a high titer of igg antibodies to asialo-gm1 (ga1) and gd3. campylobacter coli lipopolysaccharide (lps) was extracted and analyzed by elisa, immunoblot binding and blocking studies, and found to avidly bind cholera toxin and peanut agglutinin. the lps from the patient's isolate also induced anti-ga1 antibodies in a rat ...200010734265
detection and differentiation of campylobacter jejuni and campylobacter coli in broiler chicken samples using a pcr/dna probe membrane based colorimetric detection assay.campylobacter enteritis in humans has been linked to consumption of poultry meat. surveys show that 30-100% of poultry harbour campylobacter as normal flora of the digestive tract which indicates a need to identify prevalent organism types in flocks and trace their epidemiology. in this study we describe a campylobacter genus specific polymerase chain reaction (pcr) assay, amplifying the 16 s-23 s rrna intergenic spacer region with an internal campylobacter genus specific dna probe and species s ...200010725058
molecular characterization of two-component systems of helicobacter pylori.two-component systems are frequently involved in the adaptation of bacteria to changing environmental conditions at the level of transcriptional regulation. here we report the characterization of members of the two-component systems of the gastric pathogen helicobacter pylori deduced from the genome sequence of strain 26695. we demonstrate that the response regulators hp166, hp1043, and hp1021 have essential functions, as disruption of the corresponding genes is lethal for the bacteria, irrespec ...200010735847
restriction fragment length polymorphism analysis using random chromosomal gene probes for epidemiological analysis of campylobacter jejuni infections.we have evaluated the ability of a new genotyping method for campylobacter jejuni based on restriction fragment length polymorphisms using random chromosomal gene probes. dnas from c. jejuni strains digested with each of three restriction enzymes, hhai, haeiii, and hpaii, were analyzed by southern hybridization using each of two unrelated cosmid clones, p14 and p15 (respectively containing 30- and 35-kb genomic dna fragments of c. jejuni strain oh4384). the method reported provides a stable and ...200010747164
identification of campylobacter jejuni, c. coli, c. lari, c. upsaliensis, arcobacter butzleri, and a. butzleri-like species based on the glya gene.currently, the detection and identification of campylobacter and arcobacter species remains arduous, largely due to cross-species phenotypic similarities and a relatively narrow spectrum of biochemical reactivity. we have developed a pcr-hybridization strategy, wherein degenerate primers are used to amplify glya fragments from samples, which are then subjected to species-specific oligodeoxyribonucleotide probe hybridizations, to identify and distinguish between campylobacter jejuni, c. coli, c. ...200010747131
a field-suitable, semisolid aerobic enrichment medium for isolation of campylobacter jejuni in small numbers.the objective of this study was to produce an economical, easy to prepare, field-suitable enrichment medium for detection of campylobacter jejuni in small numbers. a semisolid aerobic enrichment medium was developed. rates of recovery from inoculated medium, sterile swabs, and mixed cultures of c. jejuni and coliform bacteria were tested.200010747165
antibiotic resistance trends in enteropathogenic bacteria isolated in 1985-1987 and 1995-1998 in barcelona.trends in resistance to antimicrobial agents used for therapy have been evaluated with 3,797 enteropathogenic bacteria, campylobacter, salmonella, shigella, and yersinia, between 1985-1987 and 1995-1998. the greater increase in the rate of resistance was observed in campylobacter jejuni for quinolones (from 1 to 82%) and tetracycline (from 23 to 72%) and in gastroenteric salmonellae for ampicillin (from 8 to 44%), chloramphenicol (from 1.7 to 26%), and trimethoprim-sulfamethoxazole and nalidixic ...200010770742
immobilization with metal hydroxides as a means to concentrate food-borne bacteria for detection by cultural and molecular methods.the application of nucleic acid amplification methods to the detection of food-borne pathogens could be facilitated by concentrating the organisms from the food matrix before detection. this study evaluated the utility of metal hydroxide immobilization for the concentration of bacterial cells from dairy foods prior to detection by cultural and molecular methods. using reconstituted nonfat dry milk (nfdm) as a model, two food-borne pathogens (listeria monocytogenes and salmonella enterica serovar ...200010788338
rapid and specific enzyme immunoassay on hydrophobic grid membrane filter for detection and enumeration of thermophilic campylobacter spp. from milk and chicken rinses.six commercially available anti-campylobacter antibodies were examined for their applicability in an enzyme immunoassay on hydrophobic grid membrane filters, both for the detection and enumeration of campylobacter spp. when a panel of nine campylobacter (seven campylobacter jejuni and two campylobacter coli) and eight non-campylobacter strains were used in a dot-blot format enzyme immunoassay to test the specificity of these antibodies, only one polyclonal antibody (biodesign) detected all campy ...200010772214
fecal shedding of campylobacter and arcobacter spp. in dairy cattle.campylobacter jejuni, campylobacter coli, and arcobacter spp. were detected in feces of healthy dairy cows by highly specific multiplex-pcr assays. for c. jejuni, at this one-time sampling, cows from 80.6% of farm operations (n = 31) and 37.7% of individual dairy cattle fecal samples (n = 2,085) were positive. farm management factors were correlated with prevalence in herds in which >25% of cows were positive for c. jejuni. statistical significance was set at a p of 0.20. using these criteria, a ...200010788372
computer-assisted analysis and epidemiological value of genotyping methods for campylobacter jejuni and campylobacter coli.for epidemiological tracing of the thermotolerant campylobacter species c. jejuni and c. coli, reliable and highly discriminatory typing techniques are necessary. in this study the genotyping techniques of flagellin typing (flaa typing), pulsed-field gel electrophoresis (pfge), automated ribotyping, and amplified fragment length polymorphism (aflp) fingerprinting were compared. the following aspects were compared: computer-assisted analysis, discriminatory power, and use for epidemiological typi ...200010790125
helicobacter mesocricetorum sp. nov., a novel helicobacter isolated from the feces of syrian hamsters.a spiral-shaped bacterium with bipolar, single, nonsheathed flagella was isolated from the feces of syrian hamsters. the bacterium grew as a thin spreading film at 37 degrees c under microaerobic conditions, did not hydrolyze urea, was positive for catalase and alkaline phosphatase, reduced nitrate to nitrite, did not hydrolyze hippurate, and was sensitive to nalidixic acid but resistant to cephalothin. sequence analysis of the 16s rrna gene and biochemical and phenotypic criteria indicate that ...200010790105
intercellular communication in helicobacter pylori: luxs is essential for the production of an extracellular signaling molecule.individual bacteria of numerous species can communicate and coordinate their actions via the production, release, and detection of extracellular signaling molecules. in this study, we used the vibrio harveyi luminescence bioassay to determine whether helicobacter pylori produces such a factor. cell-free conditioned media from h. pylori strains 60190 and 26695 each induced >100-fold-greater luminescence in v. harveyi than did sterile culture medium. the h. pylori signaling molecule had a molecula ...200010816463
the gale gene of campylobacter jejuni is involved in lipopolysaccharide synthesis and virulence.lipopolysaccharide (lps) is one of the main virulence factors of gram-negative bacteria. the lps from campylobacter spp. has endotoxic properties and has been shown to play a role in adhesion. we previously cloned a gene cluster (wla) which is involved in the synthesis of the campylobacter jejuni 81116 lps molecule. sequence alignment of the first gene in this cluster indicated similarity with gale genes. these genes encode a udp-glucose 4-epimerase, which catalyzes the interconversion of udp-ga ...200010768949
molecular characterization of campylobacter jejuni from patients with guillain-barré and miller fisher syndromes.campylobacter jejuni has been identified as the predominant cause of antecedent infection in guillain-barré syndrome (gbs) and miller fisher syndrome (mfs). the risk of developing gbs or mfs may be higher after infection with specific c. jejuni types. to investigate the putative clonality, 18 gbs- or mfs-related c. jejuni strains from the netherlands and belgium and 17 control strains were analyzed by serotyping (penner and lior), restriction fragment length polymorphism analysis of pcr products ...200010834992
[campylobacter coli-related meningitis in an adult male]. 200010846879
roles of fe superoxide dismutase and catalase in resistance of campylobacter coli to freeze-thaw stress.we demonstrated that oxidative stress plays a role in freeze-thaw-induced killing of campylobacter coli following analysis of mutants deficient in key antioxidant functions. superoxide anions, but not h(2)o(2), were formed during the freeze-thaw process. however, a failure to detoxify superoxide anions may lead to spontaneous disproportionation of the radicals to h(2)o(2).200010877815
helicobacter canadensis sp. nov. isolated from humans with diarrhea as an example of an emerging pathogen.we recently analyzed 11 helicobacter isolates cultured from diarrhea patients in canada. these isolates had been characterized biochemically by restriction fragment length polymorphism (rflp; alui, hhai) analysis and by fatty-acid analysis as helicobacter pullorum. however, four of the isolates differed biochemically from h. pullorum by their inability to hydrolyze indoxyl acetate and their resistance to nalidixic acid. using complete 16s rrna analysis, we determined that these four strains clus ...200010878041
slaughter pigs are commonly infected by closely related but distinct gastric ulcerative lesion-inducing gastrospirilla.an association between (unculturable) gastrospirillum-like organisms (glo) and ulcerative lesions in the pars oesophagea in stomachs of swine has been claimed. in dogs glo detected by microscopy may represent several helicobacter species or subspecies. therefore we investigated which helicobacter spp. are present in stomachs of swine and their possible association with ulcerative lesions of the pars oesophagea. the presence of helicobacter spp. in the antrum and pars oesophagea in 122 stomachs o ...200010878060
antibody to heat shock protein can be used for early serological monitoring of helicobacter pylori eradication treatment.infection with helicobacter pylori induces humoral immune responses against various antigens of the bacterium. heat shock proteins (hsps) are immunodominant antigens in various diseases including h. pylori infection. in the present study, we measured the anti-hsp antibody titers in 42 patients with h. pylori-infected peptic ulcers during a bacterial eradication study. the patients were treated with a proton pump inhibitor and antimicrobial agents to eradicate the organism. their sera were obtain ...200010882654
involvement of a plasmid in virulence of campylobacter jejuni 81-176.campylobacter jejuni strain 81-176 contains two, previously undescribed plasmids, each of which is approximately 35 kb in size. although one of the plasmids, termed ptet, carries a teto gene, conjugative transfer of tetracycline resistance to another strain of c. jejuni could not be demonstrated. partial sequence analysis of the second plasmid, pvir, revealed the presence of four open reading frames which encode proteins with significant sequence similarity to helicobacter pylori proteins, inclu ...200010899834
amplified fragment length polymorphism analysis of campylobacter jejuni strains isolated from chickens and from patients with gastroenteritis or guillain-barré or miller fisher syndrome.the high-resolution genotyping method of amplified fragment length polymorphism (aflp) analysis was used to study the genetic relationships between campylobacter jejuni strains infecting chickens (n = 54) and those causing gastroenteritis in humans (n = 53). in addition, c. jejuni strains associated with the development of guillain-barré syndrome (gbs) (n = 14) and miller fisher syndrome (mfs) (n = 4), two related acute paralytic syndromes in human, were included. strains were isolated between 1 ...200010966409
application of the 5'-nuclease pcr assay in evaluation and development of methods for quantitative detection of campylobacter jejuni.campylobacter jejuni is recognized as a leading human food-borne pathogen. traditional diagnostic testing for c. jejuni is not reliable due to special growth requirements and the possibility that this bacterium can enter a viable but nonculturable state. nucleic acid-based tests have emerged as a useful alternative to traditional enrichment testing. in this article, we present a 5'-nuclease pcr assay for quantitative detection of c. jejuni and describe its evaluation. a probe including positions ...200010966425
quantitative immunocapture pcr assay for detection of campylobacter jejuni in foods.the rapid detection of food-borne bacterial pathogens as part of a quality control program is necessary for the maintenance of a safe food supply. in this report, we present our findings for an immunocapture pcr method for the detection of campylobacter jejuni in foods. the method permits direct detection of the pathogen without an enrichment step and can be performed in approximately 8 h. assay results are quantitative, and one cell in a milliliter sample can be detected. application of the met ...200010966437
switching of flagellar motility in helicobacter pylori by reversible length variation of a short homopolymeric sequence repeat in flip, a gene encoding a basal body protein.the genome of helicobacter pylori contains numerous simple nucleotide repeats that have been proposed to have regulatory functions and to compensate for the conspicuous dearth of master regulatory pathways in this highly host-adapted bacterium. h. pylori strain 26695, whose genomic sequence was determined by the institute for genomic research (tigr), contains a repeat of nine cytidines in the flip flagellar basal body gene that splits the open reading frame in two parts. in this work, we demonst ...200010899861
rapid detection of campylobacter jejuni in stool specimens by an enzyme immunoassay and surveillance for campylobacter upsaliensis in the greater salt lake city area.the alexon-trend, inc. (ramsey, minn.), prospect campylobacter microplate assay was compared with culture on a campy-cva plate (remel, lenexa, kans.) and blood-free campylobacter agar with cefoperazone (20 microg/ml), amphotericin b (10 microg/ml), and teicoplanin (4 microg/ml) (cat medium; oxoid limited, hampshire, england) with 631 patient stool samples. the cat medium was used to isolate campylobacter upsaliensis. the enzyme immunoassay (eia) had a sensitivity and a specificity of 89 and 99%, ...200010921981
automated 5' nuclease pcr assay for identification of salmonella enterica.a simple and ready-to-go test based on a 5' nuclease (taqman) pcr technique was developed for identification of presumptive salmonella enterica isolates. the results were compared with those of conventional methods. the taqman assay was evaluated for its ability to accurately detect 210 s. enterica isolates, including 100 problematic "rough" isolates. an internal positive control was designed to use the same salmonella primers for amplification of a spiked nonrelevant template (116 bp) in the sa ...200010970396
development of a fluorogenic 5' nuclease pcr assay for detection of the ail gene of pathogenic yersinia enterocolitica.in this report we describe the development and evaluation of a fluorogenic pcr assay for the detection of pathogenic yersinia enterocolitica. the assay targets the chromosomally encoded attachment and invasion gene, ail. three primer-probe sets (tm1, tm2, and tm3) amplifying different, yet overlapping, regions of ail were examined for their specificity and sensitivity. all three primer-probe sets were able to detect between 0.25 and 0.5 pg of purified y. enterocolitica dna. tm1 identified all 26 ...200010966386
phenotypic and genotypic diversity of the flagellin gene (flic) among clostridium difficile isolates from different serogroups.phenotypic and genotypic diversity of the flagellin gene (flic) of clostridium difficile was studied in 47 isolates from various origins belonging to the serogroups a, b, c, d, f, g, h, i, k, x, and s3. electron microscopy revealed 17 nonflagellated strains and 30 flagellated strains. pcr and reverse transcription-pcr demonstrated that the flagellin gene was present in all strains and that the flic gene was expressed in both flagellated and nonflagellated strains. southern blotting showed the pr ...200010970353
comparative fingerprinting analysis of campylobacter jejuni subsp. jejuni strains by amplified-fragment length polymorphism genotyping.amplified-fragment length polymorphism (aflp) analysis with the endonucleases bglii and mfei was used to genotype 91 campylobacter jejuni subsp. jejuni strains from outbreaks and sporadic cases. aflp-generated fragments were labeled with fluorescent dye and separated by capillary electrophoresis. the software packages genescan and gelcompar ii were used to calculate aflp pattern similarities and to investigate phylogenetic relationships among the genotyped strains. the aflp method was compared w ...200010970387
characterization of gyra mutations associated with fluoroquinolone resistance in campylobacter coli by dna sequence analysis and mama pcr.increasing numbers of fluoroquinolone-resistant campylobacter coli isolates received at the minnesota state public health laboratory and at the centers for disease control and prevention have been a cause for concern. the gyra quinolone resistance-determining regions of several fluoroquinolone-resistant isolates were sequenced to examine the mechanism of resistance. ciprofloxacin-resistant c. coli isolates examined by dna sequencing had a thr-86 to ile (act-->att) gyra mutation, leading to resis ...200010981681
differentiation of clinical helicobacter pullorum isolates from related helicobacter and campylobacter species.helicobacter pullorum, first detected in the liver and intestinal contents of poultry, was defined as a new species in 1994. this organism has since been isolated from humans with gastroenteritis. phenotypic as well as genotypic methods have been used to identify h. pullorum associated with cases of human disease.200010971678
efficient isolation of campylobacteria from stools. 200010979752
sequence polymorphism, predicted secondary structures, and surface-exposed conformational epitopes of campylobacter major outer membrane protein.the major outer membrane protein (momp), a putative porin and a multifunction surface protein of campylobacter jejuni, may play an important role in the adaptation of the organism to various host environments. to begin to dissect the biological functions and antigenic features of this protein, the gene (designated cmp) encoding momp was identified and characterized from 22 strains of c. jejuni and one strain of c. coli. it was shown that the single-copy cmp locus encoded a protein with character ...200010992471
susceptibility to secondary bacterial infections in growing pigs as an early response in ochratoxicosis.mycotoxic nephropathy was induced in twelve 14 kg pigs fed a dietary component, moulded by aspergillus ochraceus and contributing ochratoxin a at 1 or 3 ppm for up to 3 weeks. concurrently, salmonellosis arose spontaneously in all six animals treated at 3 ppm and all died between days 15 and 17. two of the six pigs in the 1 ppm group died similarly but the rest, and all of six control animals, were unaffected. clinical biochemistry and histology revealed changes typical of renal ochratoxicosis i ...200010987179
evaluation of a pcr primer based on the isocitrate dehydrogenase gene for detection of helicobacter pylori in feces.in order to improve detection and identification of helicobacter pylori in highly contaminated samples, we evaluated new specific primers based on the dna base sequence within the isocitrate dehydrogenase (icd) gene to amplify a 1,200-bp dna segment. the specificity of the icd primer was tested against dna derived from various bacteria, including 7 helicobacter species and a panel of 1 gram-variable, 2 gram-positive, and 16 gram-negative bacteria, as well as dna from houseflies and feces from h. ...200011015397
evaluation of the alexon-trend prospect campylobacter microplate assay.we evaluated stool specimens known to contain or be free of campylobacter by traditional culture, using the prospect campylobacter microplate assay (alexon-trend, ramsey, minn.). this rapid enzyme immunoassay for the detection of campylobacter-specific antigens demonstrated 96% sensitivity and 99% specificity and is an acceptable alternative method of campylobacter detection.200011015419
evaluation of phenotypic and genotypic methods for subtyping campylobacter jejuni isolates from humans, poultry, and cattle.six methods for subtyping of campylobacter jejuni were compared and evaluated with a collection of 90 isolates from poultry, cattle, and sporadic human clinical cases as well as from a waterborne outbreak. the applied methods were penner heat-stable serotyping; automated ribotyping (riboprinting); random amplified polymorphic dna typing (rapd); pulsed-field gel electrophoresis (pfge); restriction fragment length polymorphisms of the flagellin gene, flaa (fla-rflp); and denaturing gradient gel el ...200011015406
characterization and expression of hmur, a tonb-dependent hemoglobin receptor of porphyromonas gingivalis.the gram-negative pathogen porphyromonas gingivalis requires hemin for growth. hemoglobin bound to haptoglobin and hemin complexed to hemopexin can be used as heme sources, indicating that p. gingivalis must have a means to remove the hemin from these host iron-binding proteins. however, the specific mechanisms utilized by p. gingivalis for the extraction of heme from heme-binding proteins and for iron transport are poorly understood. in this study we have determined that a newly identified tonb ...200011004172
antibodies, directed towards campylobacter jejuni antigens, in sera from poultry abattoir workers.occupational exposure of susceptible humans to campylobacter jejuni appears to result in resistance to disease. this is believed to be due to acquired protective immunity. to support this hypothesis the levels of c. jejuni-specific igg and igm antibodies were determined in sera from poultry abattoir workers. such individuals are persistently exposed to c. jejuni, but apparently rarely acquire campylobacteriosis. sera from 43 short-term workers (employed < or = 1 month), 78 long-term workers and ...200011012618
detection and characterization of autoagglutination activity by campylobacter jejuni.in several gram-negative bacterial pathogens, autoagglutination (aag) activity is a marker for interaction with host cells and virulence. campylobacter jejuni strains also show aag, but this property varies considerably among strains. to examine the characteristics of c. jejuni aag, we developed a quantitative in vitro assay. for strain 81-176, which shows high aag, activity was optimal for cells grown for < or = 24 h, was independent of growth temperature, and was best measured for cells suspen ...200011035721
role of catalase in campylobacter jejuni intracellular survival.the ability of campylobacter jejuni to penetrate normally nonphagocytic host cells is believed to be a key virulence determinant. recently, kinetics of c. jejuni intracellular survival have been described and indicate that the bacterium can persist and multiply within epithelial cells and macrophages in vitro. studies conducted by pesci et al. indicate that superoxide dismutase contributes to intraepithelial cell survival, as isogenic sod mutants are 12-fold more sensitive to intracellular killi ...200011035743
a novel action of the proton pump inhibitor rabeprazole and its thioether derivative against the motility of helicobacter pylori.the motility of helicobacter pylori was maximum at 37 degrees c and at ph 6. a newly developed proton pump inhibitor, rabeprazole (rpz), and its thioether derivative (rpz-th) markedly inhibited the motility of h. pylori. the concentrations of the drug necessary to inhibit 50% of the motility were 0.25, 16, 16, and >64 microgram/ml for rpz-th, rpz, lansoprazole, and omeprazole, respectively. no such inhibitory effects were observed with h(2) blockers or anti-h. pylori agents. the motilities of ca ...200011036024
milkborne campylobacter infection in hungary.in april 1998, an annual 2-day animal farm sale was held in hódmezóvásárhely, where 500 to 600 visitors consumed unpasteurized milk. the first signs of disease began 2 days after the end of the sale. fifty-two people from a wide age range fell ill, primarily with inflammatory enteritis. these cases included 34 with campylobacter positivity: 30 with campylobacter jejuni and 4 with campylobacter coli. environmental samples (raw milk, udder swabs, and rectal swabs from 12 cows in the suspected herd ...200011041145
genetics of swarming motility in salmonella enterica serovar typhimurium: critical role for lipopolysaccharide.salmonella enterica serovar typhimurium can differentiate into hyperflagellated swarmer cells on agar of an appropriate consistency (0.5 to 0.8%), allowing efficient colonization of the growth surface. flagella are essential for this form of motility. in order to identify genes involved in swarming, we carried out extensive transposon mutagenesis of serovar typhimurium, screening for those that had functional flagella yet were unable to swarm. a majority of these mutants were defective in lipopo ...200011053374
characterization of a novel outer membrane hemin-binding protein of porphyromonas gingivalis.porphyromonas gingivalis is a gram-negative, anaerobic coccobacillus that has been implicated as a major etiological agent in the development of chronic periodontitis. in this paper, we report the characterization of a protein, ihtb (iron heme transport; formerly designated pga30), that is an outer membrane hemin-binding protein potentially involved in iron assimilation by p. gingivalis. ihtb was localized to the cell surface of p. gingivalis by western blot analysis of a sarkosyl-insoluble oute ...200011053391
genotyping of clinical and chicken isolates of campylobacter jejuni and campylobacter coli.genomic dna from 58 strains of campylobacter made up of 48 campylobacter jejuni and ten campylobacter coli were digested with sma i and analysed by pulsed-field gel electrophoresis (pfge). the cleavage of dna by sma i gave 22 distinct hybridization patterns. the two campylobacter species were subtyped by pfge. the average genomic size for c. jejuni by sma i digestion was 1.73 mb, while that of c. coli gave 1.7 mb. results from this study indicate that pfge analysis by sma i digested genomic dna ...200011077971
campylobacter jejuni cytolethal distending toxin mediates release of interleukin-8 from intestinal epithelial cells.live cells of campylobacter jejuni and campylobacter coli can induce release of interleukin-8 (il-8) from int407 cells. additionally, membrane fractions of c. jejuni 81-176, but not membrane fractions of c. coli strains, can also induce release of il-8. membrane preparations from 81-176 mutants defective in any of the three membrane-associated protein subunits of cytolethal distending toxin (cdt) were unable to induce il-8. the presence of the three cdt genes on a shuttle plasmid in trans restor ...200011083762
sialylation of lipooligosaccharide cores affects immunogenicity and serum resistance of campylobacter jejuni.three genes involved in biosynthesis of the lipooligosaccharide (los) core of campylobacter jejuni msc57360, the type strain of the hs:1 serotype, whose structure mimics gm(2) ganglioside, have been cloned and characterized. mutation of genes encoding proteins with homology to a sialyl transferase (cstii) and a putative n-acetylmannosamine synthetase (neuc1), part of the biosynthetic pathway of n-acetylneuraminic acid (neunac), have identical phenotypes. the los cores of these mutants display id ...200011083778
detection on surfaces and in caco-2 cells of campylobacter jejuni cells transformed with new gfp, yfp, and cfp marker plasmids.we have developed two sets of campylobacter shuttle vectors containing either the gfp (green fluorescent protein), yfp (yellow fluorescent protein), or cfp (cyan fluorescent protein) reporter gene. in one set, the reporter gene is fused to a consensus campylobacter promoter sequence (p(c)). the other set contains a puc18 multicloning site upstream of the reporter gene, allowing the construction of transcriptional fusions using known promoters or random genomic fragments. c. jejuni cells transfor ...200011097924
purification, characterization and sequence analysis of omp50,a new porin isolated from campylobacter jejuni.a novel pore-forming protein identified in campylobacter was purified by ion-exchange chromatography and named omp50 according to both its molecular mass and its outer membrane localization. we observed a pore-forming ability of omp50 after re-incorporation into artificial membranes. the protein induced cation-selective channels with major conductance values of 50-60 ps in 1 m nacl. n-terminal sequencing allowed us to identify the predicted coding sequence cj1170c from the campylobacter jejuni g ...200011104668
evaluation of a new commercial immunoassay for rapid detection of campylobacter jejuni in stool samples.in order to evaluate a new commercial enzyme immunoassay (prospect campylobacter microplate assay; alexon-trend, usa) for the detection of campylobacter jejuni and campylobacter coli in stool samples, 30 faecal specimens known to be culture-positive for campylobacter jejuni were tested with the new assay. the detection limit was approximately 3 x 10(6)/ml in faecal suspensions. the sensitivity relative to culture was 80% (24/30). all of the 24 positive samples, except for one, remained positive ...200011117647
role of flm locus in mesophilic aeromonas species adherence.the adherence mechanism of aeromonas caviae sch3n to hep-2 cells was initially investigated through four mini-tn5 mutants that showed a 10-fold decrease in adherence. these mutants lost motility, flagella, and their lipopolysaccharide (lps) o antigen (o-ag). three genes, flmb-neua-flmd, were found to be interrupted by the transposon insertions; additionally, two other genes, one lying upstream (flma) and one downstream (neub), were found to be clustered in the same operon. while the flma and flm ...200111119490
identification of ciprofloxacin-resistant campylobacter jejuni by use of a fluorogenic pcr assay.fluoroquinolones are one class of antimicrobial agents commonly used to treat severe campylobacter jejuni infection. c. jejuni strains resistant to high levels of the fluoroquinolone ciprofloxacin (mic >/=16 microg/ml) have been predominantly characterized with a c-->t transition in codon 86 of gyra. the gyra gene encodes one subunit of dna gyrase, which is a primary target for fluoroquinolone antibiotics. this study establishes a rapid pcr-based taqman method for identifying ciprofloxacin-resis ...200011060054
identification of taxonomic and epidemiological relationships among campylobacter species by numerical analysis of aflp profiles.amplified fragment length polymorphism (aflp)-based profiling was performed on 138 strains representing all named campylobacter species and subspecies. profiles of 15/16 species comprised 6 to greater than 100 fragments and were subjected to numerical analysis. the mean similarity of 48 duplicate, outbreak and/or 'identical' strain profiles exceeded 94%. species were clearly distinguished at the 17.90% similarity (s-) level in the dendrogram. subspecies of campylobacter jejuni and campylobacter ...200011094296
the effect of thermal stress on campylobacter coli.enteropathogenic campylobacter jejuni, camp. coli and camp. lari are currently the most common cause of acute infectious diarrhoeal illness in the uk. many domestic animals, including pigs, act as natural reservoirs for these organisms and infection may occur through the ingestion of contaminated foodstuffs. the safety of locally produced porcine liver was assessed in relation to the heat susceptibility of campylobacter spp. present in eviscerated product.200011119166
campylobacter contamination of raw meat and poultry at retail sale: identification of multiple types and comparison with isolates from human infection.campylobacter species are the major cause of acute bacterial enteritis reported in the united kingdom, nonetheless many aspects of campylobacteriosis epidemiology remain poorly understood. the aim of this study was to determine the prevalence of campylobacter jejuni and campylobacter coli in fresh bovine, ovine, and porcine liver and chicken portions from retail outlets and compare strain subtype distributions with those associated with cases of human campylobacteriosis occurring within the same ...200011131886
antimicrobial properties of garlic oil against human enteric bacteria: evaluation of methodologies and comparisons with garlic oil sulfides and garlic powder.the antimicrobial effects of aqueous garlic extracts are well established but those of garlic oil (go) are little known. methodologies for estimating the antimicrobial activity of go were assessed and go, go sulfide constituents, and garlic powder (gp) were compared in tests against human enteric bacteria. test methodologies were identified as capable of producing underestimates of go activity. antimicrobial activity was greater in media lacking tryptone or cysteine, suggesting that, as for alli ...200111133485
molecular ecology of tetracycline resistance: development and validation of primers for detection of tetracycline resistance genes encoding ribosomal protection proteins.phylogenetic analysis of tetracycline resistance genes encoding the ribosomal protection proteins (rpps) revealed the monophyletic origin of these genes. the most deeply branching class, exemplified by tet and otra, consisted of genes from the antibiotic-producing organisms streptomyces rimosus and streptomyces lividans. with a high degree of confidence, the corresponding genes of the other seven classes (tet m, tet s, tet o, tet w, tet q, tet t, and tetb p) formed phylogenetically distinct sepa ...200111133424
modeling of combined processing steps for reducing escherichia coli o157:h7 populations in apple cider.probabilistic models were used as a systematic approach to describe the response of escherichia coli o157:h7 populations to combinations of commonly used preservation methods in unpasteurized apple cider. using a complete factorial experimental design, the effect of ph (3. 1 to 4.3), storage temperature and time (5 to 35 degrees c for 0 to 6 h or 12 h), preservatives (0, 0.05, or 0.1% potassium sorbate or sodium benzoate), and freeze-thaw (f-t; -20 degrees c, 48 h and 4 degrees c, 4 h) treatment ...200111133437
multilocus sequence typing system for campylobacter jejuni.the gram-negative bacterium campylobacter jejuni has extensive reservoirs in livestock and the environment and is a frequent cause of gastroenteritis in humans. to date, the lack of (i) methods suitable for population genetic analysis and (ii) a universally accepted nomenclature has hindered studies of the epidemiology and population biology of this organism. here, a multilocus sequence typing (mlst) system for this organism is described, which exploits the genetic variation present in seven hou ...200111136741
detection and initial characterization of novel capsular polysaccharide among diverse campylobacter jejuni strains using alcian blue dye.we have recently demonstrated that most strains of campylobacter jejuni produce capsular polysaccharide (cps), which can be detected by immunoblotting with homologous penner antisera on polyvinylidene difluoride membranes (a. v. karlyshev, d. linton, n. a. gregson, a. j. lastovica, and b. w. wren, mol. microbiol. 35:529-541, 2000). in this report, we describe a universal and rapid staining procedure using alcian blue for c. jejuni cps, which does not rely on the availability of antisera and iden ...200111136784
rapid detection of enterohemorrhagic escherichia coli by real-time pcr with fluorescent hybridization probes.in this report, we present a pcr protocol for rapid identification of enterohemorrhagic escherichia coli on a lightcycler instrument. in a multiplex assay, the genes encoding shiga toxin 1 and shiga toxin 2 are detected in a single reaction capillary. a complete analysis of up to 32 samples takes about 45 min.200111136804
systematic identification of selective essential genes in helicobacter pylori by genome prioritization and allelic replacement mutagenesis.a comparative genomic approach was used to identify helicobacter pylori 26695 open reading frames (orfs) which are conserved in h. pylori j99 but highly diverged in other eubacteria. a survey of selected pathways of central intermediary metabolism was also carried out, and genes with a potentially selective role in h. pylori were identified. forty-five orfs identified in these two analyses were screened using a rapid vector-free allelic replacement mutagenesis technique, and 33 were shown to be ...200111157938
allelic variation within helicobacter pylori baba and babb.helicobacter pylori strains show both geographic and disease-associated allelic variation. we investigated the diversity present in two genes, baba and babb, which are members of a paralogous family of outer membrane proteins. eleven family members within a single h. pylori strain, predicted to encode proteins with substantial n- and c-terminal similarity to each other, were classified as baba paralogues. in their central regions, most are less than 54% related to one another. examining the baba ...200111160014
clonal relationships among shigella serotypes suggested by cryptic flagellin gene polymorphism.the presence of cryptic flic alleles in the genomes of 120 strains representative of the four shigella species was investigated. one fragment was obtained by pcr amplification of flic, with a size varying from 1.2 to 3.2 kbp, depending on the species or serotype. after digestion with endonuclease hhai, the number of fragments in patterns varied from three to nine, with sizes of between 115 and 1,020 bp. patterns sharing most of their bands were grouped to constitute an f type. a total of 17 diff ...200111158126
vacuolating cytotoxin of helicobacter pylori plays a role during colonization in a mouse model of infection.helicobacter pylori, the causative agent of gastritis and ulcer disease in humans, secretes a toxin called vaca (vacuolating cytotoxin) into culture supernatants. vaca was initially characterized and purified on the basis of its ability to induce the formation of intracellular vacuoles in tissue culture cells. h. pylori strains possessing different alleles of vaca differ in their ability to express active toxin. those strains expressing higher toxin levels are correlated with more severe gastric ...200111159961
competitive exclusion of heterologous campylobacter spp. in chicks.chicken and human isolates of campylobacter jejuni were used to provide oral challenge of day-old broiler chicks. the isolation ratio of the competing challenge strains was monitored and varied, depending upon the isolates used. a pcr-restriction fragment length polymorphism assay of the flagellin gene (flaa) was used to discriminate between the chick-colonizing isolates. our observations indicated that the selected c. jejuni colonizers dominated the niche provided by the chicken ceca. chicken i ...200111157253
detection of thermophilic campylobacter from sparrows by multiplex pcr: the role of sparrows as a source of contamination of broilers with campylobacter.the best combination of primers and the annealing temperature of multiplex pcr for campylobacter jejuni, campylobacter coli, and campylobacter lari were examined. the multiplex pcr was able to detect type strains of the three species. all results of identification of wild strains (30 strains of c. jejuni, 20 strains of c. coli, and 4 strains of c. lari) by the multiplex pcr coincided with those of the conventional biochemical identification tests, suggesting that the multiplex pcr can simultaneo ...200011193345
national surveillance of campylobacter in broilers at slaughter in denmark in 1998.a surveillance study for thermophilic campylobacter spp. in broiler flocks was carried out for the year 1998 in denmark. the study included examinations of 4286 broiler flocks comprising samples from 57,000 birds. overall, a flock prevalence of 46.0% was recorded. the species distribution was campylobacter jejuni 86%, campylobacter coli 11%, campylobacter lari 1%, other not further diagnosed species 2%. the prevalence was significantly higher in the period from june to october (3.2 < odds ratio ...200011195660
novel lysophospholipase a secreted by legionella pneumophila.we show that legionella pneumophila possesses lysophospholipase a activity, which releases fatty acids from lysophosphatidylcholine. the nh2-terminal sequence of the enzyme contained fgdsls, corresponding to a catalytic domain in a recently described group of lipolytic enzymes. culture supernatants of a l. pneumophila pild mutant lost the ability to cleave lysophosphatidylcholine.200111222614
macrolide resistance in campylobacter coli of animal origin in denmark. 200111221726
essential thioredoxin-dependent peroxiredoxin system from helicobacter pylori: genetic and kinetic characterization.helicobacter pylori, an oxygen-sensitive microaerophile, contains an alkyl hydroperoxide reductase homologue (ahpc, hp1563) that is more closely related to 2-cys peroxiredoxins of higher organisms than to most other eubacterial ahpc proteins. allelic replacement mutagenesis revealed ahpc to be essential, suggesting a critical role for ahpc in defending h. pylori against oxygen toxicity. characterization of the ahpc promoter region divulged two putative regulatory elements and identified the tran ...200111222594
Displaying items 501 - 600 of 2341