Impact of a Chlorhexidine Decolonization on the Nasal and Dermal Microbiome of Therapy Dogs Participating in Hospital Animal-Assisted Intervention Programs: A Pilot Study

Therapy animals in hospital animal-assisted intervention programs are an invaluable part of holistic patient care. However, therapy dogs may be exposed to hospital-associated pathogens through these activities. This pilot study sought to examine the effect of topical chlorhexidine application, used as an infection control measure, on the microbial composition of the skin and mucous membranes of therapy dogs. We found that the chlorhexidine decolonization intervention altered microbial alpha diversity and shifted microbial structures in these therapy dogs, and particularly influenced more phylogenetically rare taxa. Specifically, the intervention reduced the abundance of Staphylococcus pseudintermedius, the archetypal canine commensal and a frequent cause of opportunistic infections. However, it did not reduce levels of S. aureus, which is a common hospital-associated pathogen of people. These preliminary findings highlight the importance of considering holistic microbial communities when undertaking infection control strategies, and stress the need for further research to understand the unintended consequences of antiseptic use on therapy dogs.