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In Europe and the United States, the genotypes of Clostridium difficile isolates that cause disease in humans and production animals overlap, particularly PCR ribotype 078, which predominates in pigs worldwide. C. difficile in piglets in Australia has not been systematically investigated, despite reports of idiopathic enteritis nationwide. It is likely that that C. difficile strains in piglets in Australia are different from those found in the rest of the world because of Australia’s geographic isolation, strict quarantine laws regarding importation of livestock, and low human population and pig density.
We studied C. difficile prevalence in scouring neonatal piglets and evaluated a novel strain of C. difficile isolated from these piglets by using multiple identification methods.
Rectal swab specimens were collected during July–November 2009 from 185 neonatal piglets on 3 farms that were experiencing scouring problems. The farms were located at 2 geographic locations in Western Australia (20 km apart) and were owned by a commercial farrow-to-finish operation. At the time of the study, 50%–80% of litters were scouring, with death rates of 11%–14%. The sick piglets had early-onset, nonhemorrhagic, yellow, pasty-to-watery diarrhea; disease course without treatment was ill-thrift, anorexia, dehydration, and death. Healthy piglets were treated prophylactically at 1–3 days of age with amoxicillin or penicillin.
Of the 185 piglets tested, C. difficile was isolated from 114 (62%): 70 (53%) of 131 piglets from the herds with severe scouring, 33 (77%) of 43 piglets from the herd with variable scouring, and 11 (100%) of 11 asymptomatic piglets. Isolates were clonal; all were novel PCR ribotype 237 and had a toxin profile of tcdA–tcdB+cdtA+cdtB+.
Our results show that a toxigenic C. difficile strain circulating in piglets in Australia is of a different ribotype, 237, than that commonly found in other parts of the world. The strain we found contained a unique PaLoc and produced more weight loss in mice than did the more common ribotype 078 animal strain. Identifying this strain is the first step in detecting and responding to this emerging disease in piglets in Australia. Future studies in swine will focus on nationwide prevalence, laboratory detection, and epidemiologic investigation to understand the transmission cycle in pigs and any relationship between animal and human disease.
Michele M. Squire, Glen P. Carter, Kate E. Mackin, Anjana Chakravorty, Torbjörn Norén, Briony Elliott, Dena Lyras, and Thomas V. Riley. Novel Molecular Type of Clostridium difficile in Neonatal Pigs, Western Australia. Emerging Infectious Diseases. 2013. Volume 19, Number 5—May 2013