Rapid identification of virulence genes in enterotoxigenic <i>Escherichia coli</i> isolates associated with diarrhoea in Queensland piggeries

T, Do; Stephens, C.P.; Townsend, K. M.; Wu, Xin; Chapman, Toni A.; Chin, James; McCormick, Benjamin; Bara, Mamta; Trott, DJ

doi:10.1111/j.1751-0813.2005.tb12745.x

Cited by 26 publications

(18 citation statements)

References 35 publications

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“…In the present study, PFGE analysis demonstrated that the DNA fingerprint of O149 isolates differed markedly from other ETEC and non-ETEC isolates, indicating that possession of the unique O149 VG profile is linked with genotype. Interestingly, the PFGE analysis showed that isolates from different geographical origins were highly clonal, and the O149 strains from Vietnam were more related to a group of Qld isolates than NSW isolates, confirming that there has been relatively little movement of E. coli populations in pigs between Qld and NSW (13). This also suggests that the Vietnamese strains probably originated from stock imported from Queensland, most probably during agricultural development programs sponsored by the Australian government (D. Trott, University of Queensland, Australia, personal communication).…”

Section: Discussionmentioning

confidence: 88%

“…The PWD isolates were obtained from diagnostic submissions (fecal swabs or intestinal contents) from animals of different geographic origins. Diagnostic criteria for designation of an isolate as a PWD strain have been given previously (13). Seventeen isolates were from southern New South Wales (NSW), Australia, 23 from Queensland (Qld), Australia, and 7 from Vietnam.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Comparative Analysis of Virulence Genes, Genetic Diversity, and Phylogeny of Commensal and Enterotoxigenic Escherichia coli Isolates from Weaned Pigs

Chapman

Trott

et al. 2007

Appl Environ Microbiol

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If the acquisition of virulence genes (VGs) for pathogenicity were not solely acquired through horizontal gene transfers of pathogenicity islands, transposons, and phages, then clonal clusters of enterotoxigenic Escherichia coli (ETEC) would contain few or even none of the VGs found in strains responsible for extraintestinal infections. To evaluate this possibility, 47 postweaning diarrhea (PWD) ETEC strains from different geographical origins and 158 commensal E. coli isolates from the gastrointestinal tracts of eight group-housed healthy pigs were screened for 36 extraintestinal and 18 enteric VGs using multiplex PCR assays. Of 36 extraintestinal VGs, only 8 were detected (fimH, traT, fyuA, hlyA, kpsMtII, k5, iha, and ompT) in the ETEC collection. Among these, hlyA (␣-hemolysin) and iha (nonhemagglutinating adhesin) occurred significantly more frequently among the ETEC isolates than in the commensal isolates. Clustering analysis based on the VG profiles separated commensal and ETEC isolates and even differentiated serogroup O141 from O149. On the other hand, pulsed-field gel electrophoresis (PFGE) successfully clustered ETEC isolates according to both serotype and geographical origin. In contrast, the commensal isolates were heterogeneous with respect to both serotype and DNA fingerprint. This study has validated the use of VG profiling to examine pathogenic relationships between porcine ETEC isolates. The clonal relationships of these isolates can be further clarified by PFGE fingerprinting. The presence of extraintestinal VGs in porcine ETEC confirmed the hypothesis that individual virulence gene acquisitions can occur concurrently against a background of horizontal gene transfers of pathogenicity islands. Over time, this could enable specific clonotypes to respond to host selection pressure and to evolve into new strains with increased virulence.Enterotoxigenic Escherichia coli (ETEC) is the major cause of postweaning diarrhea (PWD) in weaned pigs. ETEC strains colonize the small intestine with the aid of adhesion factors (e.g., F4 or F18 fimbriae). Once attached, the release of either heat-labile or heat-stable (STa or STb) enterotoxins induces diarrhea by affecting the electrolyte balance of the small intestine. The presence of virulence genes (VGs) encoding these determinants is a key requirement for pathogenicity in ETEC and is generally used to distinguish these pathogens from the nonpathogenic or commensal E. coli normally carried in the intestine (37).Characterization of isolates from outbreaks of PWD has shown that ETEC strains lacking recognized fimbriae, such as F4 and F18, are becoming more common (19,26,44). This may be related to the widespread use of vaccines incorporating fimbriated strains, providing selection pressure for the acquisition and carriage of novel, unrecognized VGs. For example, Noamani et al. (37) found that most of the PWD isolates recovered in the period 1998 to 2001 in Ontario, Canada, were associated with a new type of O149 ETEC, which possessed VGs for STa and an enteroag...

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Section: Discussionmentioning

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Comparative Analysis of Virulence Genes, Genetic Diversity, and Phylogeny of Commensal and Enterotoxigenic Escherichia coli Isolates from Weaned Pigs

Chapman

Trott

et al. 2007

Appl Environ Microbiol

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“…coli isolate from each sample was tested for the presence of virulence genes (F4, F5, F6, F18 and F41) and enterotoxin genes (STa ( estA ), STb ( estB ), Stx2e ( stx2e ) and LT ( elt )) by multiplex polymerase chain reaction (PCR) [13–15]. DNA from pure cultures of the isolates was amplified by a multiplex PCR kit protocol (QIAGEN) with slight modifications (Table 1).…”

Section: Methodsmentioning

confidence: 99%

Pre- and post-weaning scours in southeastern Australia: A survey of 22 commercial pig herds and characterisation of Escherichia coli isolates

et al. 2017

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Diarrhoeal diseases in piglets caused by Escherichia coli are responsible for substantial losses each year in the Australian pig industry. A cross-sectional survey was conducted (September 2013–May 2014) across 22 commercial pig herds located in southeastern Australia: NSW (n = 9); VIC (n = 10); and SA (n = 3), to estimate the prevalence of E. coli associated diarrhoea in pre- and post-weaned piglets and to identify key risk factors associated with E. coli disease. A questionnaire on management and husbandry practices was included. Faecal samples (n = 50 from each herd) were tested for the presence of β-haemolytic E. coli. Species level identification was confirmed by matrix-assisted laser desorption / ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). ETEC virulence and enterotoxin genes (F4, F5, F6, F18, F41, STa, STb and LT) were screened for by multiplex PCR. This study assessed 60 potential risk factors for E. coli disease in post-weaned piglets, with 2 key factors–recent disease events and the presence of bedding, statistically associated with the presence of post-weaning scours. The prevalence of diarrhea in pre-weaned pens was 17% (16/93), compared with 24% (24/102) in post-weaned pens. The most prevalent β-haemolytic ETEC genes were F18 (32%) and STb (32%) but isolates were more likely to contain F4:STb (11 of 22 herds, 23%), than F18:STb (5 of 22 herds, 6%). These findings indicate that recent disease events that have occurred within the last 12 months, and by the use of bedding or not maintaining fresh bedding can have significant impacts on piglet diarrhoea.

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“…This adhesive property was recorded only with cultures incubated at 37uC, and it was not inhibited by the presence of 1.5% Dmannose. Previously, most authors used the MRHA test as an indicator for the presumptive identification of known colonization factors, such as F4, F5, F41, 8,12,23,24 and, with some exceptions, F6 antigens. 3,22 Several reports have shown that ETEC as well as non-ETEC strains isolated from pigs can possess mannose-resistant hemagglutinating activity to different RBCs (guinea pig, horse, chicken, and pig), even without confirmation that they possessed recognized colonization factors by serologic agglutination with specific antisera.…”

Section: Discussionmentioning

confidence: 99%

“…The pathotypes of the F-strains (NVP608, NVP613, NVP1268, NVP1390, NVP1452) together with fimbriated strains (NVP1402, NVP1271, NVP2081, NVP1372) were confirmed by agglutination with F4, F5, F6, and F41 antisera and by polymerase chain reaction (PCR; with primers specific for F4, F5, F6, F41, F18, STa, STb, and LT). 11,12 The reference E. coli strains FV847a (F4-positive), 1547 (F5-positive), 1500 (F6-positive), and 1520 (F41-positive) were used as positive controls, and strain C600 (E. coli K12) was used as a fimbria-negative control in the in vitro assays.…”

Section: Bacterial Strainsmentioning

confidence: 99%

Pathogenicity of Vietnamese Enterotoxigenic Escherichia coli Strains in Colostrum-deprived One-day-old Piglets

Wilkie

Driesen³

et al. 2006

Vet Pathol

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Abstract. Preweaning colibacillosis is a major cause of economic loss to the swine industry in Vietnam. The aim of this study was to examine the enteropathogenicity of representative enterotoxigenic Escherichia coli (ETEC) strains obtained during an earlier epidemiologic survey conducted in five provinces in North Vietnam. This included isolates belonging to serotype O8 that produced heat-stable and heat-labile enterotoxins but did not produce any of the recognized fimbriae (F4, F5, F6, F41, F18). In vitro hemagglutination (unique mannose-resistant hemagglutination activity with guinea pig, sheep, human, and chicken red blood cells at 37uC, but not at 18uC) and enterocyte brush border attachment assays suggested that the F-ETEC strains produced an unidentified colonization factor that promoted adherence to the intestinal epithelium. Colostrum-deprived 1-day-old piglets challenged with an Fstrain (1-2 3 10 9 bacteria) developed acute watery diarrhea within 4 hours of inoculation and suffered up to 20% weight loss, with comparable severity to piglets challenged with conventional F4 and F5 strains. At necropsy, viable counts and histopathologic examination of intestinal sections demonstrated colonization of the duodenum, jejunum, and ileum by F4-positive strains. In comparison, the F-and F5-positive strains attached exclusively to the ileum. Transmission electron micrographs of negatively stained F-cells grown at 37uC demonstrated the presence of fimbriae. These results confirm the presence of a potentially new pathogenic ETEC fimbrial type in piggeries in Vietnam, with a unique hemagglutination property and attachment characteristics similar to ETEC bearing F5 fimbriae.

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Rapid identification of virulence genes in enterotoxigenic Escherichia coli isolates associated with diarrhoea in Queensland piggeries

Cited by 26 publications

References 35 publications

Comparative Analysis of Virulence Genes, Genetic Diversity, and Phylogeny of Commensal and Enterotoxigenic Escherichia coli Isolates from Weaned Pigs

Comparative Analysis of Virulence Genes, Genetic Diversity, and Phylogeny of Commensal and Enterotoxigenic Escherichia coli Isolates from Weaned Pigs

Pre- and post-weaning scours in southeastern Australia: A survey of 22 commercial pig herds and characterisation of Escherichia coli isolates

Pathogenicity of Vietnamese Enterotoxigenic Escherichia coli Strains in Colostrum-deprived One-day-old Piglets

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