Incidence of acquisition of methicillin-resistant Staphylococcus aureus, Clostridium difficile, and other health-care-associated pathogens by dogs that participate in animal-assisted interventions.

OBJECTIVE To determine whether dogs that visited human health-care facilities were at greater risk of acquiring certain health-care-associated pathogens, compared with dogs performing animal-assisted interventions in other settings, and to identify specific behaviors of dogs associated with an increased risk of acquiring these pathogens. DESIGN Prospective cohort and nested case-control studies. ANIMALS 96 dogs that visited human health-care facilities and 98 dogs involved in other animal-assisted interventions. PROCEDURES Fecal samples and nasal swab specimens were collected from dogs at the time of recruitment and every 2 months for 1 year and were tested for methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile, and other selected bacteria. Information was also obtained on facilities visited during animal-assisted interventions, dog diet, dog illnesses, and antimicrobial use within the home. At the end of the study, dog handlers were asked about the behavior of their dogs during visits to health-care facilities. RESULTS Rates of acquisition of MRSA and C difficile were 4.7 and 2.4 times as high, respectively, among dogs that visited human health-care facilities, compared with rates among dogs involved in other animal-assisted interventions. Among dogs that visited human health-care facilities, those that licked patients or accepted treats during visits were more likely to be positive for MRSA and C difficile than were dogs that did not lick patients or accept treats. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that dogs that visited human health-care facilities were at risk of acquiring MRSA and C difficile, particularly when they licked patients or accepted treats during visits.