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O'Mahony E.,University College Dublin | O'Mahony E.,Veterinary Food Safety Laboratory | Buckley J.F.,Veterinary Food Safety Laboratory | Bolton D.,Teagasc | And 2 more authors.

This study aimed to identify the sources and routes of transmission of Campylobacter in intensively reared poultry farms in the Republic of Ireland. Breeder flocks and their corresponding broilers housed in three growing facilities were screened for the presence of Campylobacter species from November 2006 through September 2007. All breeder flocks tested positive for Campylobacter species (with C. jejuni and C. coli being identified). Similarly, all broiler flocks also tested positive for Campylobacter by the end of the rearing period. Faecal and environmental samples were analyzed at regular intervals throughout the rearing period of each broiler flock. Campylobacter was not detected in the disinfected house, or in one-day old broiler chicks. Campylobacter jejuni was isolated from environmental samples including air, water puddles, adjacent broiler flocks and soil. A representative subset of isolates from each farm was selected for further characterization using flaA-SVR sub-typing and multi-locus sequence typing (MLST) to determine if same-species isolates from different sources were indistinguishable or not. Results obtained suggest that no evidence of vertical transmission existed and that adequate cleaning/disinfection of broiler houses contributed to the prevention of carryover and cross-contamination. Nonetheless, the environment appears to be a potential source of Campylobacter. The population structure of Campylobacter isolates from broiler farms in Southern Ireland was diverse and weakly clonal. © 2011 O'Mahony et al. Source

Drummond N.,University College Dublin | Murphy B.P.,Veterinary Food Safety Laboratory | Ringwood T.,National University of Ireland | Prentice M.B.,National University of Ireland | And 2 more authors.
Foodborne Pathogens and Disease

Yersinia enterocolitica is a zoonotic agent that causes gastrointestinal disease in humans, as well as reactive arthritis and erythema nodosum. Enteropathogenic Yersinia are the etiological agents for yersiniosis, which can be acquired through the consumption of contaminated foods. As porcine animals are the main carriers of Y. enterocolitica, food safety measures to minimize human infection are of increasing interest to the scientific and medical community. In this review, we examine why it is imperative that information on the reservoirs, prevalence, virulence, and ability of this pathogen to survive in different environments is further investigated to provide rational measures to prevent or decrease associated disease risks. © 2012, Mary Ann Liebert, Inc. Source

Lynch M.J.,Veterinary Food Safety Laboratory | Fox E.M.,Teagasc | O'Connor L.,Veterinary Food Safety Laboratory | Jordan K.,Teagasc | Murphy M.,Veterinary Food Safety Laboratory
Zoonoses and Public Health

Verocytotoxigenic Escherichia coli (VTEC) are highly significant zoonotic threats to public health, and have been the causative agent implicated in numerous high-profile outbreaks affecting large numbers of people. Serovar O157 is most frequently linked with human illness; however, other serovars, such as O26, O103, O111 and O145, have also been implicated. This study aimed to characterize the prevalence and virulence determinants of these five serovars in Irish dairy farm herds, and their milk. Using real-time PCR (RTi-PCR), bovine rectal faecal swabs and raw milk samples, along with milk filters, were screened for the presence of vt genes. Positive samples were then screened for the five serovars using sero-specific PCR. Serovar-positive samples were subjected to immunomagnetic separation, to isolate viable VTEC strains. These isolates were subsequently screened for four virulence factors: vt1, vt2, eaeA and hlyA. Three hundred and eighty six of the 600 rectal faecal swabs, 85 of the 117 milk-filters and 43 of the 120 bulk-tank milk samples, were positive for vt genes. From these 514 total vt-positive samples, 58 O26, 162 O103, 1 O111, 324 O145 and 26 O157 positives were detected by sero-specific RTi-PCR. Immunomagnetic separation yielded 12 O26, 26 O103, 0 O111, 19 O145 and 10 O157 isolates. Ten of these isolates contained at least one of the four virulence determinants screened for (i.e. vt1, vt2, eaeA and hlyA). Of these 10 isolates, pulsed-field gel electrophoresis showed that two of the O26 isolates from different farms were indistinguishable. Two O157 isolates were also indistinguishable. This study found serovars O103 and O145 to be the most prevalent in samples tested. Apart from the occurrence of VTEC in dairy herds, this study shows a high occurrence of vt genes in the environment, creating the possibility of horizontal gene transfer and emergence of new VTEC strains. © 2011 Blackwell Verlag GmbH. Source

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