Fecal Microbiota of Rhinoceros Unicornis as a Reservoir of Multi-Drug-Resistant Bacteria

The presence of Antimicrobial Resistance (AMR) bacteria in wildlife indicates the possible role of wild animals as efficient AMR reservoirs and dispersers of resistant bacteria to the human, livestock and natural environments. The presence of AMR bacteria not only has serious public health consequences, but also threatens native wildlife populations. In this study, we investigate the occurrence and antibiotic resistance patterns of fecal microbiota of Rhinoceros unicornis in Assam. Sixty two freshly voided dung samples of rhinoceros were collected from Kaziranga National Park of Assam in 2018. Fecal samples were tested for the presence of bacterial species and submitted to National Centre for Veterinary Type Cultures, National Research Centre on Equines, (NC-VTCC, NRCE) Hisar for identification. Antimicrobial Susceptibility Testing (AST) was determined using the disk diffusion method and antibiotic resistance patterns were assessed according to the Clinical and Laboratory Standards Institute (CLSI) recommendations. Overall, 24 isolates were identified that belonged to 19 different bacterial genera including Klebsiella spp., Achromobacter spp., Pseudomonas spp., Alishewanella spp., Wautersiella spp., Moraxella spp., Inquilinus spp., Weeksella spp., Oligella spp., Myroides spp., Paracoccus spp., Ochrobactrum spp., Psychrobacter spp., Pannonibacter spp., Shewanella spp., Sphingobacterium spp., Sphingomonas spp. (4% each), Escherichia coli (8%) and Acinetobacter spp. (21%). Of the 24 isolates found in rhinoceros fecal samples tested for antimicrobial susceptibility, 13 isolates showed resistant to three or more than three substance classes. Results indicate that overall, most of the bacterial species from R. unicornis were multi-drug-resistant, which may reflect not only several risk factors leading to the origin of AMR in wild animals but also wildlife as natural reservoir of resistant bacteria. Therefore, efforts must be initiated to monitor the occurrence of such AMR bacteria in wildlife and understand their potential effect on wildlife conservation and public health.