TitleAbstractYear(sorted ascending)
comparison of basal broth media for the optimal laboratory recovery of campylobacter jejuni and campylobacter coli.campylobacter species are the most common known bacterial cause of acute diarrhoeal disease and incidences are increasing yearly in ireland. concern is expressed that this increase may be due to poor laboratory techniques in recognising these organisms as they are fastidious and technically demanding to culture.200011272874
agglutination of helicobacter pylori coccoids by lectins.aim:to study the agglutination pattern of helicobacter pylori coccoid andspiral forms.methods:assays of agglutination and agglu-tination inhibition were applied using fifteen commercial lectins.results:strong agglutination was observed with mannose specific concanavalin a(con a), fucose specific tetragonolobus purpureas(lotus a) and n-acetyl glucosamine-specific triticum vulgaris (wga) lectins. mannose and fucose specific lectins were reactive with all strains of h. pylori coccoids as compared t ...200011819557
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
thermophilic campylobacter spp. in danish broiler production: a cross-sectional survey and a retrospective analysis of risk factors for occurrence in broiler order to elucidate the rate of thermophilic campylobacter spp. carriage in danish broiler production and to identify risk factors for occurrence of campylobacter in broiler flocks, a total of 88 randomly selected broiler flocks were tested for campylobacter infection, and a subsequent study of risk factors based on a questionnaire was conducted. the sample material comprised cloacal swabs from live birds before slaughter, and neck skin samples from carcasses at the end of the processing line. ...200019184798
multiplex pcr: optimization and application in diagnostic virology.pcr has revolutionized the field of infectious disease diagnosis. to overcome the inherent disadvantage of cost and to improve the diagnostic capacity of the test, multiplex pcr, a variant of the test in which more than one target sequence is amplified using more than one pair of primers, has been developed. multiplex pcrs to detect viral, bacterial, and/or other infectious agents in one reaction tube have been described. early studies highlighted the obstacles that can jeopardize the production ...200011023957
macrolide resistance conferred by base substitutions in 23s rrna. 200111120937
thermophilic campylobacters in surface water: a potential risk of campylobacteriosis.campylobacteriosis caused by campylobacter jejuni, campylobacter coli and campylobacter lari is one of the most frequently occurring acute gastroenteritis diseases in humans. an important risk factor is untreated drinking water. thermotolerant campylobacters were isolated from bø river water using 100-ml filtrate samples. campylobacters were isolated from 32 of 60 samples (53.3%). of the 75 strains isolated, 47 (62.7%) were detected using the enrichment procedure and 28 (37.2%) by direct plating ...200111798419
prevalence of salmonella, campylobacter and vtec on pig farms.four different pig farms were sampled for the prevalence of salmonella, campylobacter and verotoxigenic e. coli (vtec). pigs of different age groups and pigs of the same age were tested by taking rectal swabs. the farm environment was tested by examining overshoes, and the feed and drinking water in the pens. from a total of 215 rectal samples of individual pigs, 15 rectal samples taken from animals at the same farm were positive for salmonella. the salmonella status of the pigs at this farm dif ...200115954621
allelic diversity and recombination in campylobacter jejuni.the allelic diversity and population structure of campylobacter jejuni were studied by multilocus nucleotide sequence analysis. sequences from seven housekeeping genes were obtained from 32 c. jejuni isolates isolated from enteritis patients in germany, hungary, thailand, and the united states. also included was strain nctc 11168, the complete genomic sequence of which has recently been published. for all loci analyzed, multiple strains carried identical alleles. the frequency of synonymous and ...200111274115
use of pulsed-field gel electrophoresis and flagellin gene typing in identifying clonal groups of campylobacter jejuni and campylobacter coli in farm and clinical environments.although campylobacters have been isolated from a wide range of animal hosts, the association between campylobacters isolated from humans and animals in the farm environment is unclear. we used flagellin gene typing and pulsed-field gel electrophoresis (pfge) to investigate the genetic diversity among isolates from animals (cattle, sheep, and turkey) in farm environments and sporadic cases of campylobacteriosis in the same geographical area. forty-eight combined fla types were seen among the 315 ...200111282587
genomic relatedness within five common finnish campylobacter jejuni pulsed-field gel electrophoresis genotypes studied by amplified fragment length polymorphism analysis, ribotyping, and serotyping.thirty-five finnish campylobacter jejuni strains with five smai/sacii pulsed-field gel electrophoresis (pfge) genotypes selected among human and chicken isolates from 1997 and 1998 were used for comparison of their pfge patterns, amplified fragment length polymorphism (aflp) patterns, haeiii ribotypes, and heat-stable (hs) serotypes. the discriminatory power of pfge, aflp, and ribotyping with haeiii were shown to be at the same level for this selected set of strains, and these methods assigned t ...200111282608
genotypic analysis of escherichia coli strains from poultry carcasses and their susceptibilities to antimicrobial agents.plasmid profiling and amplified fragment length polymorphism (aflp) analysis were used to genotype 50 escherichia coli strains from poultry carcasses. thirty different plasmid profiles were evident, and clustering of the aflp data showed that they were a distinctly heterogeneous group of strains. susceptibility testing against five antimicrobial agents used in the south african poultry industry showed all strains to be susceptible to danofloxacin and colistin, while the majority (96%) were resis ...200111282652
molecular characterization of invasive and noninvasive campylobacter jejuni and campylobacter coli isolates.campylobacter jejuni is one of the most common causes of bacterial diarrhea worldwide and is the primary bacterial cause of food-borne illness. adherence to and invasion of epithelial cells are the most important pathogenic mechanisms of campylobacter diarrhea. molecular characterization of invasive and noninvasive campylobacter isolates from children with diarrhea and symptom-free children was performed by random amplified polymorphic dna techniques (rapd). a distinct rapd profile with a dna ba ...200111283056
development of an immunoassay for rapid detection of ganglioside gm(1) mimicry in campylobacter jejuni strains.mimicry of peripheral nerve gangliosides by campylobacter jejuni lipopolysaccharides (lpss) has been proposed to induce cross-reacting antiganglioside antibodies in guillain-barré syndrome (gbs). because current methods for lps characterization are labor-intensive and inhibit the screening of large numbers of strains, a rapid gm(1) epitope screening assay was developed. biomass from two agar plates of confluent growth yielded sufficient lps using a novel phenol-water and ether extraction procedu ...200111283076
specific detection and prevalence of helicobacter heilmannii-like organisms in the human gastric mucosa by fluorescent in situ hybridization and partial 16s ribosomal dna sequencing.gastric infection with helicobacter heilmannii (previously known as gastrospirillum hominis) is invariably linked with the presence of chronic gastritis and the risk of developing low-grade mucosa-associated lymphoid tissue lymphoma in humans. in contrast to helicobacter pylori, various h. heilmannii species colonize the stomachs of domestic animals, which might be a reservoir for transmission to humans (zoonosis). to identify the number and prevalence of different h. heilmanni types in humans, ...200111283079
streptococcus salivarius fimbriae are composed of a glycoprotein containing a repeated motif assembled into a filamentous nondissociable structure.streptococcus salivarius, a gram-positive bacterium found in the human oral cavity, expresses flexible peritrichous fimbriae. in this paper, we report purification and partial characterization of s. salivarius fimbriae. fimbriae were extracted by shearing the cell surface of hyperfimbriated mutant a37 (a spontaneous mutant of s. salivarius atcc 25975) with glass beads. preliminary experiments showed that s. salivarius fimbriae did not dissociate when they were incubated at 100 degrees c in the p ...200111292790
identification of thermophilic campylobacter spp. by phenotypic and molecular methods.the differences between phenotyping and genotyping (polymerase chain reaction- restriction fragment length polymorphism) of campylobacter jejuni, campylobacter coli, campylobacter lari and campylobacter upsaliensis were assessed.200111298244
bacteriophage-bacteriophage interactions in the evolution of pathogenic bacteria.many bacteriophages carry virulence genes encoding proteins that play a major role in bacterial pathogenesis. recently, investigators have identified bacteriophage-bacteriophage interactions in the bacterial host cell that also contribute significantly to the virulence of bacterial pathogens. the relationships between the bacteriophages pertain to one bacteriophage providing a helper function for another, unrelated bacteriophage in the host cell. accordingly, these interactions can involve the m ...200111303502
survival of campylobacter jejuni during stationary phase: evidence for the absence of a phenotypic stationary-phase response.when campylobacter jejuni nctc 11351 was grown microaerobically in rich medium at 39 degrees c, entry into stationary phase was followed by a rapid decline in viable numbers to leave a residual population of 1% of the maximum number or less. loss of viability was preceded by sublethal injury, which was seen as a loss of the ability to grow on media containing 0.1% sodium deoxycholate or 1% sodium chloride. resistance of cells to mild heat stress (50 degrees c) or aeration was greatest in exponen ...200111319108
study of the infectivity of saline-stored campylobacter jejuni for day-old chicks.the culturability of three campylobacter jejuni strains and their infectivity for day-old chicks were assessed following storage of the strains in saline. the potential for colonization of chicks was weakened during the storage period and terminated 3 to 4 weeks before the strains became nonculturable. the results from this study suggest that the role of starved and aged but still culturable campylobacters may be diminutive, but even more, that the role of viable but nonculturable stages in camp ...200111319130
recommendations of the subcommittee on the taxonomy of campylobacter and related bacteria.the icsb subcommittee on the taxonomy of campylobacter and related bacteria has discussed several contemporaneous issues and makes the following recommendations. (i) the reported synonymy between campylobacter coli and campylobacter hyoilei was based on valid taxonomic arguments. the subcommittee therefore discourages the use of the name c. hyoilei. (ii) the revised infrasubspecific nomenclature of campylobacter sputorum is endorsed. c sputorum is subdivided into c. sputorum biovar sputorum (cha ...200111321120
rapid pulsed-field gel electrophoresis protocol for subtyping of campylobacter jejuni.we developed a rapid pulsed-field gel electrophoresis (pfge) protocol for subtyping campylobacter isolates based on the standardized protocols used by pulsenet laboratories for the subtyping of other food-borne bacterial pathogens. various combinations of buffers, reagents, reaction conditions (e.g., cell suspension concentration, lysis time, lysis temperature, and restriction enzyme concentration), and electrophoretic parameters were evaluated in an effort to devise a protocol that is simple, r ...200111326009
comparison of two methods for serotyping campylobacter spp.two serotyping schemes (penner and laboratory of enteric pathogens [lep]) based on soluble heat-stable antigens were used to analyze 3,788 campylobacter sp. isolates. a significant percentage (36.6%) was untypeable using lep serotyping; greater cross-reaction was also observed. the relative discrimination capabilities of the techniques were similar. penner serotyping fulfils more of the requisite criteria for typing methods.200111326013
superoxide dismutase-deficient mutants of helicobacter pylori are hypersensitive to oxidative stress and defective in host colonization.superoxide dismutase (sod) is a nearly ubiquitous enzyme among organisms that are exposed to oxic environments. the single sod of helicobacter pylori, encoded by the sodb gene, has been suspected to be a virulence factor for this pathogenic microaerophile, but mutations in this gene have not been reported previously. we have isolated mutants with interruptions in the sodb gene and have characterized them with respect to their response to oxidative stress and ability to colonize the mouse stomach ...200111349073
changes in the carriage of campylobacter strains by poultry carcasses during processing in abattoirs.the recent development of simple, rapid genotyping techniques for campylobacter species has enabled investigation of the determinative epidemiology of these organisms in a variety of situations. in this study we have used the technique of fla typing (pcr-restriction fragment length polymorphism analysis of the flaa and flab genes) to identify the sources of strains contaminating the carcasses of five campylobacter-positive and two campylobacter-negative broiler flocks during abattoir processing. ...200111375174
evidence that certain clones of campylobacter jejuni persist during successive broiler flock rotations.through the national surveillance program for campylobacter spp., nine broiler chicken farms that were infected with campylobacter jejuni in at least five rotations in 1998 were identified. one additional farm, located at the island of bornholm where divided slaughter is used extensively, was also selected. twelve broiler houses located on 10 farms were included in the study. the c. jejuni isolates collected from the selected houses during the surveillance were typed using fla typing and macrore ...200111375189
etiology of children's diarrhea in montevideo, uruguay: associated pathogens and unusual isolates.we studied microorganisms associated with infant diarrhea in a group of 256 children admitted to a public pediatric hospital in montevideo, uruguay. diagnostic procedures were updated to optimize detection of potential pathogens, which were found in 63.8% of cases, and to be able to define their characteristics down to molecular or antigenic type. coinfection with two or more agents was detected in more than one-third of positive studies. escherichia coli enteric virotypes, especially enteropath ...200111376047
coinfection of enteric helicobacter spp. and campylobacter spp. in cats.during a 6-year period, 64 of 227 commercially reared cats had microaerobic bacteria isolated from their feces. all the isolates were initially identified as campylobacter-like organisms based on biochemical and phenotypic characteristics. dna extractions from 51 of these isolates were subjected to pcr using primers specific for helicobacter spp. and campylobacter spp. of the isolates, 92% (47 of 51 isolates) were positive for campylobacter spp., 41% (21 of 51 isolates) were positive for helicob ...200111376052
rapid identification of campylobacter spp. by melting peak analysis of biprobes in real-time pcr.we describe rapid pcr-biprobe identification of campylobacter spp. this is based on real-time pcr with product analysis in the same system. the assay identifies enteropathogenic campylobacters to the species level on the basis of their degree of hybridization to three 16s ribosomal dna (rdna) biprobes. first-round symmetric pcr is performed with genus-specific primers which selectively target and amplify a portion of the 16s rrna gene common to all campylobacter species. second-round asymmetric ...200111376061
comparative study using amplified fragment length polymorphism fingerprinting, pcr genotyping, and phenotyping to differentiate campylobacter fetus strains isolated from animals.a collection of campylobacter fetus strains, including both c. fetus subsp. fetus and c. fetus subsp. venerealis, were phenotypically identified to the subspecies level and genotypically typed by pcr and amplified fragment length polymorphism (aflp) analysis. phenotypic subspecies determination methods were unreliable. genotyping of the strains by pcr and aflp showed a clear discrimination between the two subspecies.200111376071
changes in campylobacter jejuni and campylobacter coli carriage rates in the zenica region [correction of zenica canton] of bosnia and herzegovina in the pre- and postwar periods. 200111388169
differential gene expression from two transcriptional units in the cag pathogenicity island of helicobacter pylori.infection with helicobacter pylori strains containing the cag pathogenicity island (cag pai) is strongly correlated with the development of severe gastric disease, including gastric and duodenal ulceration, mucosa-associated lymphoid tissue lymphoma, and gastric carcinoma. although in vitro studies have demonstrated that the expression of genes within the cag pai leads to the activation of a strong host inflammatory response, the functions of most cag gene products and how they work in concert t ...200111401955
cdta, cdtb, and cdtc form a tripartite complex that is required for cytolethal distending toxin activity.campylobacter jejuni encodes a cytolethal distending toxin (cdt) that causes cells to arrest in the g(2)/m transition phase of the cell cycle. highly related toxins are also produced by other important bacterial pathogens. cdt activity requires the function of three genes: cdta, cdtb, and cdtc. recent studies have established that cdtb is the active subunit of cdt, exerting its effect as a nuclease that damages the dna and triggers cell cycle arrest. microinjection of cdtb into target cells led ...200111401974
differentiation between campylobacter hyoilei and campylobater coli using genotypic and phenotypic analyses.genotypic and phenotypic methods were applied to investigate differences between the closely related species campylobacter hyoilei and campylobacter coli. a unique dna sequence from c. hyoilei was used to design a specific pcr assay that amplified a dna product of 383 bp for all c. hyoilei strains, but not other campylobacter species, including c. coli. the pcr assay could detect 100 fg pure c. hyoilei dna, 2 x 10(2) c.f.u. ml(-1) using cultured cells and 8.3 x 10(3) c.f.u. 0.1 g(-1) in faeces. ...200111411703
serotype and genotype diversity and hatchery transmission of campylobacter jejuni in commercial poultry flocks.we investigated the genotype and serotype diversity of campylobacter coli and c. jejuni in two parent flocks of adult hens and their offspring over two rotations in order to evaluate the role of hatchery mediated transmission and/or vertical transmission of campylobacters in broiler flocks. in total, 314 c. jejuni and 32 c. coli isolates from parent and broiler flocks and from the surroundings of broiler houses were typed by flagellin gene pcr/rflp (fla-typing), and selected isolates were also t ...200111423205
comparison of genotypes and serotypes of campylobacter jejuni isolated from danish wild mammals and birds and from broiler flocks and humans.the incidence of human infection with campylobacter jejuni is increasing in most developed countries and the reason for this is largely unknown. although poultry meat is considered to be a major source, it is evident that other reservoirs exist, possibly common to humans and poultry. environmental sources are believed to be important reservoirs of campylobacter infection in broiler chicken flocks. we investigated the potential importance of wildlife as a source of infection in commercial poultry ...200111425730
evaluation of methods for subtyping campylobacter jejuni during an outbreak involving a food october 1998, the centers for disease control and prevention (cdc) assisted in an investigation of an outbreak of campylobacteriosis at a school in salina, kansas. twenty-two isolates were submitted from the kansas state public health laboratory to cdc, 9 associated with the outbreak and 13 epidemiologically unrelated sporadic isolates. pulsed-field gel electrophoresis (pfge) using smai and sali was initially used to validate the epidemiologic data. we then tested the ability of other subtypi ...200111427543
helicobacter winghamensis sp. nov., a novel helicobacter sp. isolated from patients with gastroenteritis.from 1997 to 1999 seven isolates of campylobacter-like organisms from five patients that were exhibiting symptoms of gastroenteritis, including fever, stomach malaise, and diarrhea, were investigated. the organisms were isolated from stool samples and found to exhibit a diverse colony morphology; hence multiple isolates were submitted from one of the patients. all isolates were found to be identical. the organisms were catalase, urease, alkaline phosphatase, and nitrate negative but oxidase and ...200111427547
genomic heterogeneity and o-antigenic diversity of campylobacter upsaliensis and campylobacter helveticus strains isolated from dogs and cats in germany.a serotyping scheme based on heat-stable surface antigens was established for 101 campylobacter upsaliensis and 10 campylobacter helveticus strains isolated from 261 dogs and 46 cats of different ages originating from two geographically distinct regions in germany. the prevalence of c. upsaliensis varied between 27.8% in juvenile dogs (<12 months of age) and 55.4% in adult dogs (p < 0.05). of the cats, 19.6% harbored c. upsaliensis, whereas 21.7% carried c. helveticus. of the c. upsaliensis isol ...200111427567
development of a ceue-based multiplex polymerase chain reaction (pcr) assay for direct detection and differentiation of campylobacter jejuni and campylobacter coli in thailand.a novel ceue-based multiplex pcr system was developed as an efficient diagnostics test to detect and differentiate c. jejuni and c. coli. there is no cross reactivity between c. jejuni and c. coli. in addition, the assay does not produce a positive signal from other enteric bacteria including salmonella, shigella and escherichia coli strains. campylobacter detection sensitivity was determined to be equivalent to previously reported pcr for other enteric bacteria. we also noticed that silicon dio ...200111448558
identification of the carbohydrate moieties and glycosylation motifs in campylobacter jejuni flagellin.flagellins from three strains of campylobacter jejuni and one strain of campylobacter coli were shown to be extensively modified by glycosyl residues, imparting an approximate 6000-da shift from the molecular mass of the protein predicted from the dna sequence. tryptic peptides from c. jejuni 81-176 flagellin were subjected to capillary liquid chromatography-electrospray mass spectrometry with a high/low orifice stepping to identify peptide segments of aberrant masses together with their corresp ...200111461915
iron-dependent transcription of the frpb gene of helicobacter pylori is controlled by the fur repressor protein.we have overexpressed and purified the helicobacter pylori fur protein and analyzed its interaction with the intergenic regions of divergent genes involved in iron uptake (frpb and ceue) and oxygen radical detoxification (kata and tsaa). dnase i footprint analysis showed that fur binds specifically to a high-affinity site overlapping the p(frpb) promoter and to low-affinity sites located upstream from promoters within both the frpb-kata and ceue-tsaa intergenic regions. construction of an isogen ...200111466300
antimicrobial susceptibilities of campylobacter strains isolated from food animals in belgium.campylobacter spp. are a frequent cause of diarrhoea in man, originating mostly from poultry. it has been suggested that the veterinary use of antibiotics is largely responsible for resistance in human isolates, particularly to quinolones. during a 6 month period from june to december 1998, 677 campylobacter isolates were obtained from healthy poultry and pigs. samples were taken at belgian slaughterhouses. species identification was performed by biochemical tests, multiplex pcr and sds-page of ...200111481294
a genomic island in pseudomonas aeruginosa carries the determinants of flagellin glycosylation.protein glycosylation has been long recognized as an important posttranslational modification process in eukaryotic cells. glycoproteins, predominantly secreted or surface localized, have also been identified in bacteria. we have identified a cluster of 14 genes, encoding the determinants of the flagellin glycosylation machinery in pseudomonas aeruginosa pak, which we called the flagellin glycosylation island. flagellin glycosylation can be detected only in bacteria expressing the a-type flagell ...200111481492
cytolethal distending toxin demonstrates genotoxic activity in a yeast model.cytolethal distending toxins (cdts) are multisubunit proteins produced by a variety of bacterial pathogens that cause enlargement, cell cycle arrest, and apoptosis in mammalian cells. while their function remains uncertain, recent studies suggest that they can act as intracellular dnases in mammalian cells. here we establish a novel yeast model for understanding cdt-associated disease. expression of the cdtb subunit in yeast causes a g2/m arrest, as seen in mammalian cells. cdtb toxicity is not ...200111500452
intracellular redox status and antibiotic resistance in enterogastric micro-aerophilic bacteria: evidence for the 'scavenging of oxygen' hypothesis.metronidazole and glutathione reduction activities were measured in situ in the micro-aerophilic bacteria campylobacter coli and helicobacter pylori employing 14n- and 1h-nuclear magnetic resonance spectroscopy. the properties of these enzyme activities were investigated in matched pairs of strains with sensitive and resistant phenotypes to the antimicrobial metronidazole. the results indicated that the ability of each type of strain to reduce metronidazole corresponded to its sensitive or resis ...200111523593
prevalence, antigenic specificity, and bactericidal activity of poultry anti-campylobacter maternal antibodies.poultry are considered the major reservoir for campylobacter jejuni, a leading bacterial cause of human food-borne diarrhea. to understand the ecology of c. jejuni and develop strategies to control c. jejuni infection in the animal reservoir, we initiated studies to examine the potential role of anti-campylobacter maternal antibodies in protecting young broiler chickens from infection by c. jejuni. using an enzyme-linked immunosorbent assay (elisa), the prevalence of anti-c. jejuni antibodies in ...200111525990
survival of clinical and poultry-derived isolates of campylobacter jejuni at a low temperature (4 degrees c).campylobacter jejuni is a leading cause of bacterial gastroenteritis in humans, and contamination of poultry has been implicated in illness. the bacteria are fastidious in terms of their temperature requirements, being unable to grow below ca. 31 degrees c, but have been found to be physiologically active at lower temperatures and to tolerate exposure to low temperatures in a strain-dependent manner. in this study, 19 field isolates of c. jejuni (10 of clinical and 9 of poultry origin) were stud ...200111526022
sequence typing confirms that campylobacter jejuni strains associated with guillain-barré and miller-fisher syndromes are of diverse genetic lineage, serotype, and flagella type.guillain-barré syndrome (gbs) and miller-fisher syndrome (mfs) are correlated with prior infection by campylobacter jejuni in up to 40% of cases. nucleotide sequence-based typing of 25 c. jejuni isolates associated with neuropathy permitted robust comparisons with equivalent data from approximately 800 c. jejuni isolates not associated with neuropathy. a total of 13 genetic lineages and 20 flaa short variable region nucleotide sequences were present among the 25 isolates. a minority of isolates ...200111526174
phenotyping of campylobacter jejuni and campylobacter coli by a quantitative antibiogram [mic] typing scheme using euclidean distances [qated].background: enteropathogenic campylobacter jejuni and c. coli are presently the most common cause of acute bacterial gastroenteritis in the developed world. an understanding of sources and means of transmission of campylobacter is an essential factor in order to reduce the incidence of campylobacter-related gastroenteritis in man. consequently a reproducible, sensitive and well-standardised typing scheme is critical in the successful discrimination of strains and in the subsequent investigations ...200111527505
structural investigations of the active-site mutant asn156ala of outer membrane phospholipase a: function of the asn-his interaction in the catalytic triad.outer membrane phospholipase a (ompla) from escherichia coli is an integral-membrane enzyme with a unique his-ser-asn catalytic triad. in serine proteases and serine esterases usually an asp occurs in the catalytic triad; its role has been the subject of much debate. here the role of the uncharged asparagine in the active site of ompla is investigated by structural characterization of the asn156ala mutant. asparagine 156 is not involved in maintaining the overall active-site configuration and do ...200111567087
taxonomy and identification of the burkholderia cepacia complex. 200111574551
molecular identification of campylobacter concisus.a 1.6-kb dna fragment isolated from a campylobacter concisus genomic library gave c. concisus-specific restriction fragment length patterns when it was used as a probe in hybridization studies. all of the strains tested, including type strains and clinical isolates, contained a 0.5-kb hindiii fragment that hybridized to the probe. dna sequencing of the 1.6-kb fragment identified three open reading frames (orfs). one of the orfs encodes the carboxy terminus of gyrb, and the translational products ...200111574591
differentiation of campylobacter species by aflp fingerprinting.the fluorescent amplified fragment length polymorphism (aflp) fingerprinting method was tested for its ability to identify and subtype the most important campylobacter species found in veterinary infections. sixty-nine reference strains and 19 clinical isolates of campylobacter jejuni subsp. jejuni, campylobacter jejuni subsp. doylei, campylobacter upsaliensis, campylobacter coli, campylobacter lari, campylobacter fetus subsp. fetus, c. fetus subsp. venerealis, campylobacter hyointestinalis subs ...200111577152
molecular detection of antimicrobial resistance.the determination of antimicrobial susceptibility of a clinical isolate, especially with increasing resistance, is often crucial for the optimal antimicrobial therapy of infected patients. nucleic acid-based assays for the detection of resistance may offer advantages over phenotypic assays. examples are the detection of the methicillin resistance-encoding meca gene in staphylococci, rifampin resistance in mycobacterium tuberculosis, and the spread of resistance determinants across the globe. how ...200111585788
whole genome comparison of campylobacter jejuni human isolates using a low-cost microarray reveals extensive genetic diversity.campylobacter jejuni is the leading cause of bacterial food-borne diarrhoeal disease throughout the world, and yet is still a poorly understood pathogen. whole genome microarray comparisons of 11 c. jejuni strains of diverse origin identified genes in up to 30 nctc 11168 loci ranging from 0.7 to 18.7 kb that are either absent or highly divergent in these isolates. many of these regions are associated with the biosynthesis of surface structures including flagella, lipo-oligosaccharide, and the ne ...200111591647
aminoglycoside-streptothricin resistance gene cluster aade-sat4-apha-3 disseminated among multiresistant isolates of enterococcus faecium.seventy-two enterococcus faecium isolates of different origins highly resistant to nourseothricin and streptomycin were studied. sequencing of a genomic fragment from two isolates identified a gene cluster, aade-sat4-apha-3, which has been isolated recently in staphylococci and campylobacter coli. patterns of digested pcr products of aade-sat4-apha-3 were identical for all isolates.200111600397
genome sequence-based fluorescent amplified fragment length polymorphism of campylobacter jejuni, its relationship to serotyping, and its implications for epidemiological analysis.the published genome sequence of campylobacter jejuni strain nctc 11168 was used to model an accurate and highly reproducible fluorescent amplified fragment length polymorphism (faflp) analysis. predicted and experimentally observed amplified fragments (afs) generated with the primer pair hindiii+a and hhai+a were compared. all but one of the 61 predicted afs were reproducibly detected, and no unpredicted fragments were amplified. this faflp analysis was used to genotype 74 c. jejuni strains bel ...200111682493
bacterial genetic fingerprint: a reliable factor in the study of the epidemiology of human campylobacter enteritis?the rate of human intestinal infections with more than a single campylobacter strain was determined and the genetic variabilities of campylobacter strains throughout an infection episode were investigated by means of pulsed-field gel electrophoresis (pfge) and enterobacterial repetitive intergenic consensus sequence pcr (eric-pcr). for 48 and 49 of 50 patients, all isolates from one sample showed identical patterns by pfge and eric-pcr, respectively. throughout an infection episode in 47 of 52 p ...200111682547
evaluation of a pcr/dna probe colorimetric membrane assay for identification of campylobacter spp. in human stool specimens.dna was extracted from 50 human stool specimens using the qiaamp dna stool minikit. pcr amplification was followed by post-pcr hybridization to dna probes specific for the campylobacter genus, campylobacter jejuni, and campylobacter coli in a colorimetric membrane assay. thirty-two of 38 culture-positive specimens were pcr/dna probe positive for c. jejuni. the assay is rapid and simple and can be applied to stool specimens for the detection of campylobacter.200111682549
phase variation in the helicobacter pylori phospholipase a gene and its role in acid adaptation.previously, we have shown that helicobacter pylori can spontaneously and reversibly change its membrane lipid composition, producing variants with low or high content of lysophospholipids. the "lyso" variant contains a high percentage of lysophospholipids, adheres better to epithelial cells, and releases more proteins such as urease and vaca, compared to the "normal" variant, which has a low content of lysophospholipids. prolonged growth of the normal variant at ph 3.5, but not under neutral con ...200111705905
identification, characterization, and variation in expression of two serologically distinct o-antigen epitopes in lipopolysaccharides of campylobacter fetus serotype a strains.monoclonal antibodies (mabs) to the lipopolysaccharide (lps) o-antigens of campylobacter fetus serotype a and b strains were produced. eight mabs specific for serotype a lps were characterized on immunoblots of c. fetus serotype a lps. two immunoblot patterns were observed and were used to divide the eight mabs into two groups. mabs m1177 and m1194 were selected as representative of the two groups and were used in an enzyme-linked immunosorbent assay (elisa) to examine the lps o-antigen epitopes ...200111705938
trichuris suis: detection of antibacterial activity in excretory-secretory products from adults.antibacterial activity was detected in excretory-secretory products (esp) of adult trichuris suis cultured in vitro in serum-free media. gram-negative bacteria (campylobacter jejuni, campylobacter coli, and escherichia coli) and gram-positive bacteria (staphylococcus aureus) were sensitive to esp. susceptibility was dependent on the concentration of esp but not on the inoculum size. preliminary assessment of the mode of action suggests a bacteriocidal mechanism. this antibacterial activity was h ...200111708831
efficient isolation of campylobacter upsaliensis from stools. 200111712518
prevalence of campylobacter spp., escherichia coli, and salmonella serovars in retail chicken, turkey, pork, and beef from the greater washington, d.c., area.a total of 825 samples of retail raw meats (chicken, turkey, pork, and beef) were examined for the presence of escherichia coli and salmonella serovars, and 719 of these samples were also tested for campylobacter spp. the samples were randomly obtained from 59 stores of four supermarket chains during 107 sampling visits in the greater washington, d.c., area from june 1999 to july 2000. the majority (70.7%) of chicken samples (n = 184) were contaminated with campylobacter, and a large percentage ...200111722889
detection of hepatitis a virus by the nucleic acid sequence-based amplification technique and comparison with reverse transcription-pcr.a nucleic acid sequence-based amplification (nasba) technique for the detection of hepatitis a virus (hav) in foods was developed and compared to the traditional reverse transcription (rt)-pcr technique. oligonucleotide primers targeting the vp1 and vp2 genes encoding the major hav capsid proteins were used for the amplification of viral rna in an isothermal process resulting in the accumulation of rna amplicons. amplicons were detected by hybridization with a digoxigenin-labeled oligonucleotide ...200111722911
development of a pcr elisa assay for the identification of campylobacter jejuni and campylobacter coli.a polymerase chain reaction (pcr) assay was developed based on a solution-hybridization colorimetric end-point detection format (pcr elisa) for the identification of campylobacter jejuni and campylobacter coli. pcr primers were designed to target a gene sequence with species-specific motifs. five biotin-labelled probes targeted to the species-specific motifs were investigated for the detection of digoxygenin-labelled pcr products from c. jejuni and c. coli using the pcr elisa format. two probes ...200111735301
an optimised recovery method for thermophilic campylobacter from liver.the past three decades have witnessed the rise of campylobacter enteritis in man from virtual obscurity to notoriety, with present isolation rates superseding those of other enteric pathogens such as salmonella spp. and shigella spp. in most developed countries. although campylobacters are not completely new to applied bacteriology, they have evaded traditional isolation techniques used for the isolation of pure cultures, apart from single isolations that were free from competing organisms. offa ...200111741507
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
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
evidence for a genetically stable strain of campylobacter jejuni.the genetic stability of selected epidemiologically linked strains of campylobacter jejuni during outbreak situations was investigated by using subtyping techniques. strains isolated from geographically related chicken flock outbreaks in 1998 and from a human outbreak in 1981 were investigated. there was little similarity in the strains obtained from the different chicken flock outbreaks; however, the strains from each of three chicken outbreaks, including strains isolated from various environme ...200111229909
antibody responses to campylobacter infections determined by an enzyme-linked immunosorbent assay: 2-year follow-up study of 210 enzyme-linked immunosorbent assay (elisa) was adapted to measure immunoglobulin g (igg), igm, and iga classes of human serum antibody to campylobacter jejuni and campylobacter coli. heat-stable antigen, a combination of c. jejuni serotype o:1,44 and o:53 in the ratio 1:1, was used as a coating antigen in the elisa test. a total of 631 sera from 210 patients with verified campylobacter enteritis were examined at various intervals after infection, and a control group of 164 sera were tested to ...200111238214
in vitro transposition system for efficient generation of random mutants of campylobacter jejuni.campylobacter jejuni is the most common cause of food-borne illnesses in the united states. despite the fact that the entire nucleotide sequence of its genome has recently become available, its mechanisms of pathogenicity are poorly understood. this is in part due to the lack of an efficient mutagenesis system. here we describe an in vitro transposon mutagenesis system based on the staphylococcus aureus transposable element tn552 that allows the efficient generation of insertion mutants of c. je ...200111244083
pcr-elisas for the detection of campylobacter jejuni and campylobacter coli in poultry samples.campylobacter species, primarily campylobacter jejuni and campylobacter coli, are regarded as a major cause of human gastrointestinal disease, commonly acquired by eating undercooked chicken. we describe a pcr-elisa for the detection of campylobacter species and the discrimination of c. jejuni and c. coli in poultry samples. the pcr assay targets the 16s/23s ribosomal rna intergenic spacer region of campylobacter species with dna oligonucleotide probes designed for the specific detection of c. j ...200111252796
helicobacter pylori resists phagocytosis by macrophages: quantitative assessment by confocal microscopy and fluorescence-activated cell sorting.helicobacter pylori infection of the stomach epithelium is characterized by an infiltration of polymorphonuclear and mononuclear cells. these immune cells contribute to mucosal damage which may eventually lead to gastritis, peptic ulcer, gastric cancer, and/or malt-associated gastric lymphoma. here we show that h. pylori inhibits its own uptake, as well as in trans the phagocytosis of neisseria gonorrhoeae, by human and murine macrophages. this antiphagocytic activity is dependent on the presenc ...200111254625
quinolone and macrolide resistance in campylobacter jejuni and c. coli: resistance mechanisms and trends in human isolates.the incidence of human campylobacter jejuni and c. coli infections has increased markedly in many parts of the world in the last decade as has the number of quinolone-resistant and, to a lesser extent, macrolide-resistant campylobacter strains causing infections. we review macrolide and quinolone resistance in campylobacter and track resistance trends in human clinical isolates in relation to use of these agents in food animals. susceptibility data suggest that erythromycin and other macrolides ...200111266291
extent of microbial contamination in united states pork retail determine the extent of microbiological contamination of u.s. pork, 384 samples of retail pork were collected from 24 stores in six cities, including (i) whole-muscle, store-packaged pork; (ii) fresh, store-packaged ground pork and/or pork sausage; (iii) prepackaged ground pork and/or pork sausage; and (iv) whole-muscle, enhanced (injected or marinated; 60% store-packaged, 40% prepackaged) pork. additional samples (n = 120) of freshly ground pork and/or pork sausage were collected from two ho ...200111271763
[antagonistic activity of lactobacillus bacteria strains against anaerobic gastrointestinal tract pathogens (helicobacter pylori, campylobacter coli, campylobacter jejuni, clostridium difficile)].antagonistic activity of lactobacillus strains has been known for some time. this property is connected with production of many active substances by lactobacilli e.g., organic acids and bacteriocin-like substances which interfere with other indigenous microorganisms inhabiting the same ecological niche, including also anaerobic gastrointestinal tract pathogens. growing interest of clinical medicine in finding new approaches to treatment and prevention of common inflammatory infections of the dig ...200111757422
single or double mutational alterations of gyra associated with fluoroquinolone resistance in campylobacter jejuni and campylobacter coli.we looked for the presence of gyra mutations in seven fluoroquinolone-resistant french clinical isolates of campylobacter jejuni and campylobacter coli. three of the five isolates of c. jejuni and the two isolates of c. coli had high-level resistance to nalidixic acid (mics 128-256 microg/ml) and ciprofloxacin (mics 32 microg/ml). a gyra mutation was found in all these isolates leading to the following substitutions: thr86-ile in four cases and asp90-tyr for one c. coli strain. one isolate had h ...200111759087
isolation and polymerase chain reaction-based detection of campylobacter jejuni and campylobacter coli from poultry in the philippines.the polymerase chain reaction (pcr) and the conventional culture method of detecting thermophilic campylobacter species in duck and chicken samples from two locations in the province of laguna, philippines, were compared. three campylobacter jejuni and five c. coli strains were isolated from a total of 135 duck and chicken samples from both methods. the pcr technique, however, was found to be more sensitive, accurate and rapid than the conventional culture method. the specificity of two sets of ...200111759758
investigations of waterborne pathogens in eurasian beaver (castor fiber) from telemark county, southeast norway. 200111957376
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
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
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 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
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
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
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
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
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
comparison of rheumatological and gastrointestinal symptoms after infection with campylobacter jejuni/coli and enterotoxigenic escherichia estimate the incidence of postinfectious joint complaints after campylobacter jejuni/coli enteritis compared with enteritis caused by enterotoxigenic e coli (etec). to compare gastrointestinal symptoms, antibiotic treatment, and antibody levels among patients with and without joint symptoms.200211959770
molecular evolution of human immunodeficiency virus env in humans and monkeys: similar patterns occur during natural disease progression or rapid virus passage.neonatal rhesus macaque 95-3 was inoculated with nonpassaged simian-human immunodeficiency virus strain shiv-vpu(+), which encodes env of the laboratory-adapted human immunodeficiency virus (hiv) strain iiib and is considered nonpathogenic. cd4(+) t-cell counts dropped to <200 cells/microl within 4.6 years, and monkey 95-3 died with opportunistic infections 5.9 years postinoculation. transfer of blood from 95-3 to two naive adult macaques resulted in high peak viral loads and rapid, persistent t ...200211967343
development and application of a new scheme for typing campylobacter jejuni and campylobacter coli by pcr-based restriction fragment length polymorphism analysis.a molecular typing approach for campylobacter jejuni and campylobacter coli was developed with restriction fragment length polymorphism analysis of a 9.6-kb pcr-amplified portion of the lipopolysaccharide gene cluster. sixty-one penner serotype reference strains were analyzed with this new genotyping scheme, and 32 genogroups were found. eleven additional genogroups were obtained from 87 clinical c. jejuni strains tested. this molecular typing method shows a correlation with the penner heat-stab ...200211980961
detection of campylobacter jejuni and campylobacter coli in foods by enrichment culture and polymerase chain reaction enzyme-linked immunosorbent assay.a polymerase chain reaction (pcr) assay based on a solution hybridization format with colorimetric end-point detection (pcr elisa) was investigated for the specific detection of campylobacter jejuni and campylobacter coli in food samples following enrichment culture. one hundred fifteen samples of raw meat and offal (poultry, porcine, ovine, and bovine), raw shellfish, and artificially contaminated milk were enriched in blood-free campylobacter enrichment broth for 48 h. enrichment cultures were ...200212030285
comparison of 23s polymerase chain reaction-restriction fragment length polymorphism and amplified fragment length polymorphism techniques as typing systems for thermophilic this study, we evaluated the combination of polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) and amplified fragment length polymorphism (aflp) molecular typing techniques for the analysis of thermophilic campylobacter species isolated from clinical and poultry samples. 23s pcr-rflp analysis performed to fingerprint 69 strains exhibited an excellent level of typability. eleven different types were defined at 100% linkage level following numerical analysis of band p ...200212052557
cecal colonization of chicks by porcine strains of campylobacter coli.ten genotypically distinct strains of campylobacter coli were isolated from a swine production facility. these porcine isolates were then orally inoculated into day-of-hatch leghorn chicks and were excellent colonizers of the chick cecum. campylobacter coli recovered from inoculated chickens were genotypically identical to the challenge strain. the absence of host specificity suggests a possible movement of strains among swine, field animals and birds, and poultry houses.200212061661
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