Clostridioides (Clostridium) difficile colonises the gastrointestinal tract of humans and animals and it is the leading cause of infectious diarrhea in hospitalised humans. Despite significant research advances on C. difficile, most studies have focused on clinical and epidemiological aspects of infection with relatively less emphasis on exploring the ecology and evolution of C. difficile. To address this deficiency this project aims to gain some insights into the ecology of C. difficile in different endemic animal hosts.
A total of 324 faecal samples were collected from wild/captive reptiles (n=101), mammals (n=124) and birds (n=99) in Western Australia. C. difficile was isolated by anaerobic selective enrichment and culture. Statistical comparisons and ecological analysis were performed using R Studio. Isolates were characterised by PCR ribotyping and toxin gene profile. Overall prevalence was 36.11% (n=117/324) with a total of 23 different strains and four toxin gene profiles. Prevalence in reptiles and mammals was similar (55.4%, n=56/101 and 42.74%, n=53/124 (p-value = 0.137), respectively) but significantly lower in birds (8.08%, n=8/99, p<0.00001 for both reptiles and mammals). Logistic regression analysis revealed significant differences and associations with C. difficile presence and distribution between the three classes and their behaviours. Species richness and diversity (alpha diversity index) underscored a higher diversity in mammals and reptiles compared to birds. Beta diversity showed a marked ribotyping similarity across the three animal classes.
This report sought to address for the first time a lack of understanding in the ecology of C. difficile in Australian native animals, providing insights into the prevalence, molecular epidemiology and ecology of C. difficile in this unique environment.