title: Longitudinal prevalence, faecal shedding and molecular characterisation of Campylobacter spp. and Salmonella enterica in sheep.
abstract: Faecal excretion of Campylobacter spp. and Salmonella enterica in sheep in Australia was determined using a quantitative multiplex PCR (qPCR) targeting the Campylobacter spp. purine biosynthesis gene (PurA) and the S. enterica outer membrane protein (ompF). The mutiplex qPCR was specific and Campylobacter spp. and S. enterica were each detected with a sensitivity of 5 organisms/µL faecal DNA extract. This multiplex qPCR was used to determine the prevalence and concentration of Campylobacter spp. and S. enterica in 3412 faecal samples collected from 1189 lambs on eight farms across South Australia (n = 2 farms), New South Wales (n = 1), Victoria (n = 2) and Western Australia (n = 3) at three sampling periods (weaning, post-weaning and pre-slaughter). The overall prevalences of Campylobacter spp. and S. enterica were 13.3% and 5.0%, respectively, with the highest prevalence for Campylobacter spp. in South Australia and the highest prevalence for S. enterica in New South Wales. Campylobacter jejuni was the only Campylobacter sp. identified from a subset of 120 positive samples sequenced at the 16S locus. S. enterica serovar Typhimurium was the only serovar of S. enterica identified from a subset of 120 positive samples sequenced at the ompF locus. Across all states, Campylobacter spp. had the highest median bacterial concentration in faeces at weaning and post-weaning (medians of 3.4 × 10(6) and 1.1 × 10(5), respectively), whereas S. enterica had the highest median bacterial concentration at pre-slaughter (1.8 × 10(5)/g faeces).
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia.
authors.forename: Rongchang
authors.initials: R
authors.lastname: Yang
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia.
authors.forename: Caroline
authors.initials: C
authors.lastname: Jacobson
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia.
authors.forename: Graham
authors.initials: G
authors.lastname: Gardner
authors.affiliation: South Australian Research and Development Institute, 33 Flemington Street, Glenside, South Australia 5065, Australia.
authors.forename: Ian
authors.initials: I
authors.lastname: Carmichael
authors.affiliation: Faculty of Veterinary Science, University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia.
authors.forename: Angus J D
authors.initials: AJ
authors.lastname: Campbell
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia. Electronic address: Una.Ryan@murdoch.edu.au.
authors.forename: Una
authors.initials: U
authors.lastname: Ryan
mesh_terms: D000818:Animals; D001315:Australia / Q000453:epidemiology; D057138:Bacterial Shedding; D002167:Campylobacter / Q000302:isolation & purification*; D002169:Campylobacter Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D008137:Longitudinal Studies; D060885:Multiplex Polymerase Chain Reaction / Q000662:veterinary*; D015995:Prevalence; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology; D019779:Salmonella enterica / Q000302:isolation & purification*; D012621:Seasons; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000382:microbiology
keywords: Campylobacter spp; Quantitative PCR; Salmonella enterica; Sheep; ompF; purA