Environmental ESKAPE Organisms and Other Environmental Equine-Specific Indicator Pathogens—Are They Relevant in Equine Nosocomial Wound Infections?

Background: Multidrug-resistant organisms increasingly challenge infection prevention and control (IPC) in equine referral hospitals. Objectives: Assessment of selected environmental indicator pathogens in an equine teaching hospital and evaluation of their relevance for nosocomial wound infections. Study design: Observational study with repeated environmental sampling and retrospective evaluation of wound culture submissions. Methods: During three sampling periods (SPs), surface samples were collected across functional areas before and after routine cleaning/disinfection. Revision of the cleaning/disinfection protocols and environmental support staff feedback and training was performed between SP 1 and 2. Indicator pathogens were defined as an equine-adapted ESKAPEE-derived panel. Samples from surgical wounds were considered nosocomial if infection developed ≥3 days after hospitalisation. Results: Indicator pathogens were detected in all SPs, with the greatest frequency and diversity in SP 1. SP 1 yielded indicator pathogens in 25.7% of the 152 samples. After IPC optimisation, detection decreased in SP 2 to 11.2% of the 152 samples. In SP 3 with fewer samples (n = 42) sporadic recovery (7.1%) was observed. Contamination involved in particular high-touch surfaces and floors, and several pathogens persisted after cleaning/disinfection. Of 125 wounds, 38 met the criteria for nosocomial infection. Isolated from both, the environment and infected wounds were Streptococcus equi ssp. zooepidemicus, Staphylococcus aureus, Escherichia coli, and Enterobacter cloacae. Molecular typing was unavailable. Conclusions: Environmental equine-relevant indicator pathogens were detected across clinical areas. Some persisted after routine cleaning and/or were detected in nosocomial wound infections. Revision of cleaning/disinfection protocols with staff training was temporarily associated with reduced environmental contamination.