Bovine Campylobacter jejuni strains differ from human and chicken strains in an analysis of certain molecular genetic markers.
ABSTRACT: The association of four new genetic markers with a chicken, bovine, or human host was studied among 645 Campylobacter jejuni isolates. The gamma-glutamate transpeptidase gene and dmsA were common in human and chicken isolates but uncommon among bovine isolates. In the t test, bovine isolates differed significantly (P < 0.05) from human and chicken isolates.
Project description:In this study, we describe the association of three Campylobacter jejuni metabolism-related traits, ?-glutamyl-transpeptidase (GGT), fucose permease (fucP), and secreted L-asparaginase [ansB(s)], with multilocus sequence types (STs). A total of 710 C. jejuni isolates with known STs were selected and originated from humans, poultry, bovines, and the environment. Among these isolates, we found 31.1% to produce GGT and 49.3% and 30.3% to be positive for ansB(s) and fucP, respectively. The combination of GGT production, the presence of ansB(s), and the absence of fucP was associated with ST-22, ST-586, and the ST-45 and ST-283 clonal complexes (CCs), which were the main STs and CCs found among the human and chicken isolates. The ST-21 CC was associated with the presence of fucP and was the major CC among the bovine isolates. Although the ST-61 CC was the second major CC among the bovine isolates, these isolates did not have any of the markers studied, making the role of fucP in bovine gut colonization questionable. The ST-45 CC was subdivided into three groups that were attributed solely to ST-45. One group showed a marker combination described previously, another group was found to be positive for ansB(s) only, and the third group did not have any of the markers studied. These results suggest that the host association of these markers seems to be indirect and may arise as a consequence of host-ST and -CC associations. Thus, a representative collection of STs should be tested to draw sensible conclusions in similar studies.
Project description:In this study, multilocus sequence typing (MLST) was combined with the genetic detection of six genetic markers, ansB, dmsA, ggt, cj1585c, cjj81176-1367/71 (cj1365c), and the two-gene marker tlp7 (cj0951c plus cj0952c), to assess if their presence correlated with different C. jejuni clonal groups. Using a collection of 266 C. jejuni isolates from (in decreasing order of sample size) humans, chickens, cattle, and turkeys, it was further investigated whether the resulting genotypes correlated with the isolation source. We found combinations of the six marker genes to be mutually exclusive, and their patterns of presence or absence correlated to some degree with animal source. Together with MLST results, the obtained genotypes could be segregated into six groups. An association was identified for ansB, dmsA, and ggt with the MLST-clonal complexes (MLST-CC) 22, 42, 45, and 283, which formed the most prominent group, in which chickens were the most prevalent animal source. Two other groups, characterized by the presence of cj1585c, cjj81176-1367/71, and the two-gene marker tlp7, associated with either MLST-CC 21 or 61, were overrepresented in isolates of bovine origin. Mutually exclusive marker gene combinations were observed for ansB, dmsA, and ggt, typically found in CC 45 and the related CC 22, 42, and 283, whereas the other three marker genes were found mostly in CC 21, 48, and 206. The presence of the two-gene marker tlp7, which is typical for MLST 21 and 53 as well as for MLST-CC 61, strongly correlates with a bovine host; this is interpreted as an example of host adaptation. In cases of C. jejuni outbreaks, these genetic markers could be helpful for more effective source tracking.
Project description:Here, we report the draft genome sequences of robust (A74/C_24-3) and poor (A74/O_2-2) chicken-colonizing Campylobacter jejuni isolates. Whole-genome sequence analyses of these isolates will be helpful in facilitating further studies to identify genetic factors used in chicken colonization.
Project description:Pulsed-field gel electrophoresis fingerprints of 98 Campylobacter jejuni isolates from patients (85) and chicken carcasses (13) in Hong Kong in 2002 demonstrated high genetic diversity. The prevalence of quinolone resistance among the isolates was 85.9%, and replacement of the threonine-86 residue in the gyrase subunit A was the major resistance mechanism.
Project description:BACKGROUND: Campylobacter jejuni and Campylobacter coli are human intestinal pathogens of global importance. Zoonotic transmission from livestock animals or animal-derived food is the likely cause for most of these infections. However, little is known about their general and host-specific mechanisms of colonization, or virulence and pathogenicity factors. In certain hosts, Campylobacter species colonize persistently and do not cause disease, while they cause acute intestinal disease in humans. RESULTS: Here, we investigate putative host-specificity using phenotypic characterization and genome-wide analysis of genetically closely related C. jejuni strains from different sources. A collection of 473 fresh Campylobacter isolates from Germany was assembled between 2006 and 2010 and characterized using MLST. A subset of closely related C. jejuni strains of the highly prevalent sequence type ST-21 was selected from different hosts and isolation sources. PCR typing of strain-variable genes provided evidence that some genes differed between these strains. Furthermore, phenotypic variation of these strains was tested using the following criteria: metabolic variation, protein expression patterns, and eukaryotic cell interaction. The results demonstrated remarkable phenotypic diversity within the ST-21 group, which however did not correlate with isolation source. Whole genome sequencing was performed for five ST-21 strains from chicken, human, bovine, and food sources, in order to gain insight into ST-21 genome diversity. The comparisons showed extensive genomic diversity, primarily due to recombination and gain of phage-related genes. By contrast, no genomic features associated with isolation source or host were identified. CONCLUSIONS: The genome information and phenotypic data obtained in vitro and in a chicken infection model provided little evidence of fixed adaptation to a specific host. Instead, the dominant C. jejuni ST-21 appeared to be characterized by phenotypic flexibility and high genetic microdiversity, revealing properties of a generalist. High genetic flexibility might allow generalist variants of C. jejuni to reversibly express diverse fitness factors in changing environments.
Project description:Complete genome sequences of Campylobacter coli strains WA333, YF2105, BG2108, MG1116, and BP3183 and Campylobacter jejuni strain IF1100 isolated from retail chicken liver showed the presence of 1,841,551-, 1,687,232-, 1,695,638-, 1,665,146-, 1,695,360-, and 1,744,171-bp circular chromosomes, respectively. These isolates also contained plasmids ranging in size from 5,209 to 55,122 bp.
Project description:Sequencing of the VP2 region was carried out to identify amino acid mismatches between vaccine strains and field isolates of infectious bursal disease virus (IBDV). Viruses were isolated in chicken embryo fibroblast (DF-1) cells using pooled samples of bursa collected from nine outbreaks, which affected 30,250 chickens in five localities, with an overall mortality of 47.87%. Virus strains were identified by comparing the deduced amino acid sequence between positions 232 and 446 of the immunodominant VP2 epitope. All of the pooled samples were positive for IBDV. RT-PCR yielded a 645-bp DNA fragment of the VP2 gene. Phylogenetic analysis of this fragment revealed clustering of these isolates with very virulent IBDV strains. The amino acid sequences of these isolates were identical to those of the European very virulent strains UK 661 and DV 86, except at position 222, but differed from the vaccine strains used in Ethiopia, suggesting the possible introduction of virulent virus strains to Ethiopia from Europe. Our study demonstrates the widespread presence of very virulent strains of IBDV on poultry farms in Ethiopia and demonstrates the need to evaluate the protective level of existing vaccines against circulating field viruses.
Project description:BACKGROUND: Waterborne Campylobacter jejuni outbreaks are common in the Nordic countries, and PFGE (pulsed field gel electrophoresis) remains the genotyping method of choice in outbreak investigations. However, PFGE cannot assess the clonal relationship between isolates, leading to difficulties in molecular epidemiological investigations. Here, we explored the applicability of whole genome sequencing to outbreak investigation by re-analysing three C. jejuni strains (one isolated from water and two from patients) from an earlier resolved Finnish waterborne outbreak from the year 2000. RESULTS: One of the patient strains had the same PFGE profile, as well as an identical overall gene synteny and three polymorphisms in comparison with the water strain. However, the other patient isolate, which showed only minor differences in the PFGE pattern relative to the water strain, harboured several polymorphisms as well as rearrangements in the integrated element CJIE2. We reconstructed the genealogy of these strains with ClonalFrame including in the analysis four C. jejuni isolated from chicken in 2012 having the same PFGE profile and sequence type as the outbreak strains. The three outbreak strains exhibited a paraphyletic relationship, implying that the drinking water from 2000 was probably contaminated with at least two different, but related, C. jejuni strains. CONCLUSIONS: Our results emphasize the capability of whole genome sequencing to unambiguously resolve the clonal relationship between isolates of C. jejuni in an outbreak situation and evaluate the diversity of the C. jejuni population.
Project description:Campylobacter jejuni is one of the most common causes of human foodborne bacterial infections worldwide. The objective of this study was to assess the molecular diversity, using flaA sequencing, of 602 C. jejuni isolated from chicken food chain, i.e., chicken feces (n = 151), chicken carcasses (n = 150), chicken meat (n = 150), and from humans (n = 151) and to determine antimicrobial multiresistant profiles of the isolates as well as to analyze the relationship of the isolate genotypes with their antimicrobial resistance profiles and source of isolation. Multidrug resistant patterns were identified in 110 (18.3%) C. jejuni isolates recovered from all sources and most isolates were resistant to ciprofloxacin (CIP), nalidixic acid (NAL), streptomycin (STR), and tetracycline (TET) (92; 15.3%) or ciprofloxacin, streptomycin, and tetracycline (13; 2.2%). Only a few isolates were multiresistant to ciprofloxacin, nalidixic acid, tetracycline, and erythromycin (3; 0.5%) or ciprofloxacin, nalidixic acid, streptomycin, tetracycline, and erythromycin (2; 0.3%). A total of 79 flaA-SVR subtypes were identified, including 40 (50.6%) unique to the isolates' origins, with the most common sequence types 16, 54, 36, 34, and 287 which covered 56 (9.3%), 50 (8.3%), 48 (8.0%), 35 (5.8%), and 32 (5.3%) of C. jejuni isolates, respectively. It was found that 13 isolates had the novel flaA-SVR subtypes which were not present in the pubMLST database. These isolates were recovered from chicken feces (6 isolates), carcasses (2 isolates), meat (one isolate) and from humans (4 isolates). Multiresistant C. jejuni were classified into 26 different sequence subtypes. Among the most numerous multidrug resistant profile CIP+NAL+STR+TET 21 different flaA-SVR subtypes, with total of 92 isolates, were identified. Most of them were classified to 287 (18; 19.6% isolates), 100 (13; 14.1%), 34 (9; 9.8%), 208 (8; 8.7%), and 781 (8; 8.7%) molecular variants. Isolates resistant to CIP, STR and TET (13 isolates) were mainly from chicken feces (12 isolates) and classified into 5 flaA-SVR sequence types, with the most common 36 (8 isolates). The obtained results show a broad molecular diversity of multiresistant C. jejuni isolates and suggest chickens as a possible source of human Campylobacter infections in Poland.
Project description:Campylobacter jejuni colonization of chickens is presumably dependent upon multiple surface-exposed proteins termed adhesins. Putative C. jejuni adhesins include CadF, CapA, JlpA, major outer membrane protein, PEB1, Cj1279c, and Cj1349c. We examined the genetic relatedness of 97 C. jejuni isolates recovered from human, poultry, bovine, porcine, ovine, and canine sources by multilocus sequence typing (MLST) and examined their profile of putative adhesin-encoding genes by dot blot hybridization. To assess the individual contribution of each protein in bacterium-host cell adherence, the C. jejuni genes encoding the putative adhesins were disrupted by insertional mutagenesis. The phenotype of each mutant was judged by performing in vitro cell adherence assays with chicken LMH hepatocellular carcinoma epithelial cells and in vivo colonization assays with broiler chicks. MLST analysis indicated that the C. jejuni isolates utilized in this study were genetically diverse. Dot blot hybridization revealed that the C. jejuni genes encoding the putative adhesins, with the exception of capA, were conserved among the isolates. The C. jejuni CadF, CapA, Cj1279c, and Cj1349c proteins were found to play a significant role in the bacterium's in vitro adherence to chicken epithelial cells, while CadF, PEB1, and Cj1279c were determined to play a significant role in the bacterium's in vivo colonization of broiler chicks. Collectively, the data indicate that Cj1279c is a novel adhesin. Because Cj1279c harbors fibronectin type III domains, we designated the protein FlpA, for fibronectin-like protein A.