Background: Clostridium difficile infection (CDI) is a leading cause of healthcare-related infections in humans, and an emerging pathogen in livestock. CDI outbreaks have been reported in piggeries outside Australia.
Aim: To characterise an outbreak of CDI occurring in a piggery in Victoria.
Methods: Thirty rectal swabs and 12 samples of colon contents were obtained from diarrhoeic litters, the latter during necropsy. Selective toxigenic culture and standard molecular methods (PCR ribotyping) were used to detect and characterise C. difficile isolates. To determine the association between infection and diarrhoea, necropsy and histopathology were performed on a subset of infected piglets. Ten isolates were tested for metronidazole and moxifloxacin susceptibility using E-strips.
Results: The prevalence of C. difficile in samples was 64% (27/42). An unusual PCR ribotype (RT) QX 450 (A+B+CDT+) (100%, 27/27) was the only one found in the piggery. All necropsied piglets had oedematous spiral colon, mild to severe mesocolonic oedema with neutrophilia. On histopathology, severe colonic erosions with large numbers of bacilli adherent to the mucosal surface were common in infected piglets. All 10 isolates were susceptible to metronidazole (MIC range 0.016-0.047ug/mL) and moxifloxacin (MIC 0.75ug/mL).
Conclusions: In this study, there was a clonal clustering of an unusual RT QX 450, which is often characteristic of a common source CDI outbreak. These findings are typical of CDI outbreaks in piglets worldwide. The outbreak was contained after using sodium hypochlorite disinfectant for cleaning in pig sheds. A need exists for early detection and control of this pathogen in piggeries.