Active surveillance in an equine intensive care unit identifies clusters of ESKAPEE pathogens in the veterinary hospital environment

Healthcare-associated infections (HAIs) associated with ESKAPEE pathogens are an emerging concern in equine hospitals, especially in the intensive care unit (ICU). To gain insight into the occurrence of HAIs and to identify potential reservoirs and transmission routes of ESKAPEE pathogens in an equine ICU, a pilot study of two periods (December 2022-January 2023 and April-June 2023) was performed, where patient and environmental samples were obtained upon ICU admission and discharge. A sampling and laboratory protocol for the detection and identification of different ESKAPEE pathogens and Salmonella spp. was developed. Samples consisted of patient samples and patient-bound environmental samples, including nose and environmental swabs, feces, twitch ropes and catheter tips. Non-patient bound samples were collected from high-contact surfaces for staff members. In total, 271 patient-bound samples (n = 122 in sampling period 1 and n = 149 in sampling period 2) from 30 patients and 28 non-patient bound environmental samples were collected resulting in the isolation of 207 ESKAPEE isolates. A selection of isolates (n = 115) was sequenced to identify clusters and antimicrobial resistance genes. ESKAPEE pathogens were present in 90 % of the horses hospitalized at the ICU or their immediate environment. Different genetic clusters of MRSA, A. baumannii and E. cloacae isolates were identified over time suggesting transmission and persistence within the ICU. During both sampling periods no HAIs were observed, but the abundance of these pathogens might pose a risk for HAIs. This study shows the importance for every (veterinary) hospital to implement surveillance and to further optimize hygiene protocols.