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Publications (5)12.89 Total impact

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    ABSTRACT: To examine healthy slaughter-age cattle and sheep on-farm for the excretion of Salmonella serovars in faeces and to identify possible risk factors using a questionnaire. The study involved 215 herds and flocks in the four eastern states of Australia, 56 with prior history of salmonellosis. Production systems examined included pasture beef cattle, feedlot beef cattle, dairy cattle, prime lambs and mutton sheep and animals were all at slaughter age. From each herd or flock, 25 animals were sampled and the samples pooled for Salmonella culture. All Salmonella isolated were serotyped and any Salmonella Typhimurium isolates were phage typed. Questionnaires on each production system, prepared in Epi Info 6.04, were designed to identify risk factors associated with Salmonella spp excretion, with separate questionnaires designed for each production system. Salmonellae were identified in all production systems and were more commonly isolated from dairies and beef feedlots than other systems. Statistical analysis revealed that dairy cattle were significantly more likely to shed Salmonella in faeces than pasture beef cattle, mutton sheep and prime lambs (P<0.05). A wide diversity of Salmonella serovars, all of which have been isolated from humans in Australia, was identified in both cattle and sheep. Analysis of the questionnaires showed access to new arrivals was a significant risk factor for Salmonella excretion on dairy properties. For beef feedlots, the presence of large numbers of flies in the feedlot pens or around stored manure were significant risk factors for Salmonella excretion. Dairy cattle pose the highest risk of all the slaughter-age animals tested. Some of the identified risk factors can be overcome by improved management practices, especially in relation to hygiene.
    Australian Veterinary Journal 01/2008; 85(12):498-502. · 0.92 Impact Factor
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    ABSTRACT: Shiga toxin-producing Escherichia coli (STEC) strains possessing genes for enterohemolysin (ehxA) and/or intimin (eae), referred to here as complex STEC (cSTEC), are more commonly recovered from the feces of humans with hemolytic uremic syndrome and hemorrhagic colitis than STEC strains that do not possess these accessory virulence genes. Ruminants, particularly cattle and sheep, are recognized reservoirs of STEC populations that may contaminate foods destined for human consumption. We isolated cSTEC strains from the feces of longitudinally sampled pasture-fed sheep, lot-fed sheep maintained on diets comprising various combinations of silage and grain, and sheep simultaneously grazing pastures with cattle to explore the diversity of cSTEC serotypes capable of colonizing healthy sheep. A total of 67 cSTEC serotypes were isolated, of which 21 (31.3%), mainly isolated from lambs, have not been reported. Of the total isolations, 58 (86.6%) were different from cSTEC serotypes isolated from a recent study of longitudinally sampled healthy Australian cattle (M. Hornitzky, B. A. Vanselow, K. Walker, K. A. Bettelheim, B. Corney, P. Gill, G. Bailey, and S. P. Djordjevic, Appl. Environ. Microbiol. 68:6439-6445, 2002). Our data suggest that cSTEC serotypes O5:H(-), O75:H8, O91:H(-), O123:H(-), and O128:H2 are well adapted to colonizing the ovine gastrointestinal tract, since they were the most prevalent serotypes isolated from both pasture-fed and lot-fed sheep. Collectively, our data show that Australian sheep are colonized by diverse cSTEC serotypes that are rarely isolated from healthy Australian cattle.
    Applied and Environmental Microbiology 08/2004; 70(7):3910-7. · 3.95 Impact Factor
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    ABSTRACT: In a study of faeces from 475 slaughter-age cattle and sheep from 19 herds or flocks, Campylobacter species (C. jejuni and C. coli) were cultured from all production systems studied and from 73.7 per cent (14/19) of herds or flocks. Within individual properties there was a higher prevalence in cattle than in sheep, with Campylobacter being most commonly isolated from feedlot cattle. The median prevalences and ranges were: for dairy cattle, six per cent (0-24%), feedlot beef cattle, 58 per cent (12-92%) pasture beef cattle, two per cent (0-52%), mutton sheep, 0 per cent (0-4%) and prime lambs eight per cent. Listeria ivanovii was cultured from one dairy cow but Yersinia enterocolitica was not cultured from any animal. Campylobacter is the leading bacterial causative agent of acute diarrhoea in humans in many industrialised countries. While the role of cattle and sheep in producing human campylobacteriosis either directly or via contaminated food, remains to be epidemiologically clarified, this study suggests that the production system, particularly for cattle, may be an important consideration.
    Communicable diseases intelligence 02/2003; 27(2):249-57.
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    ABSTRACT: The virulence properties and serotypes of complex Shiga toxin-producing Escherichia coli (cSTEC) were determined in two studies of healthy cattle in eastern Australia. In the first, a snapshot study, 84 cSTEC isolates were recovered from 37 of 1,692 (2.2%) fecal samples collected from slaughter-age cattle from 72 commercial properties. The second, a longitudinal study of three feedlots and five pasture beef properties, resulted in the recovery of 118 cSTEC isolates from 104 animals. Of the 70 serotypes identified, 38 had not previously been reported.
    Applied and Environmental Microbiology 01/2003; 68(12):6439-45. · 3.95 Impact Factor
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    ABSTRACT: A group of 1,623 ovine fecal samples recovered from 65 geographically distinct mutton sheep and prime lamb properties across New South Wales, Australia, were screened for the presence of Shiga toxin-producing Escherichia coli (STEC) virulence factors (stx(1), stx(2), eaeA, and ehxA). A subset was cultured for STEC isolates containing associated virulence factors (eaeA and/or ehxA), which were isolated from 17 of 20 (85%) and 19 of 20 (95%) tested prime lamb and mutton sheep properties, respectively. STEC isolates containing stx(1), stx(2), and ehxA were most commonly isolated (19 of 40 flocks; 47.5%), and this profile was observed for 10 different serotypes. Among 90 STEC isolates studied, the most common serotypes were O91:H(-) (22 isolates [24.4%]), O5:H(-) (16 isolates [17.8%]), O128:H2 (11 isolates [12.2%]), O123:H(-) (8 isolates [8.9%]), and O85:H49 (5 isolates [5.6%]). Two isolates (2.2%) were typed as O157:H(-). A total of 78 of 90 STEC isolates (86.7%) expressed Shiga toxin in Vero cell culture and 75 of 84 ehxA-positive isolates (89.3%) expressed enterohemolysin on washed sheep blood agar. eaeA was observed in 11 of 90 (12.2%) ovine STEC isolates, including serotypes O5:H(-), O84:H(-), O85:H49, O123:H(-) O136:H40, and O157:H(-). Although only 2 of 90 isolates were typed as O157:H(-), the predominant serotypes recovered during this study have been recovered from human patients with clinical disease, albeit rarely.
    Journal of Clinical Microbiology 06/2001; 39(5):2017-21. · 4.07 Impact Factor