Molecular epidemiology and environmental persistence of methicillin-resistant coagulase-positive Staphylococci in a Veterinary Teaching Hospital in Thailand: Evidence for nosocomial transmission and One Health implications

Field: Veterinary (Health Sciences)

Background and Aim: Methicillin-resistant coagulase-positive Staphylococci (MRCoPS), including methicillin-resistant Staphylococcus pseudintermedius (MRSP), methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-resistant Staphylococcus coagulans (MRSC), are emerging zoonotic pathogens in veterinary hospitals, posing significant infection control challenges. This study aimed to investigate the molecular epidemiology, antimicrobial resistance profiles, and clonal dissemination of MRCoPS across environmental surfaces, veterinary personnel, and canine patients at the Veterinary Teaching Hospital, Chulalongkorn University (VTH-CU), Thailand. Materials and Methods: A cross-sectional study was conducted involving 216 environmental samples, 23 veterinary staff, and 14 canine patients. Isolates were identified using biochemical tests, polymerase chain reaction (PCR), and matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry. Methicillin resistance was confirmed by mecA gene detection. Antimicrobial susceptibility was evaluated through disk diffusion following Clinical and Laboratory Standards Institute guidelines. Molecular typing was performed using staphylococcal cassette mec (SCCmec) PCR and pulsed-field gel electrophoresis (PFGE). Multivariate logistic regression identified environmental predictors of MRCoPS contamination. Results: Among 88 coagulase-positive isolates, 62 (70.5%) were methicillin resistant, predominantly MRSP (91.9%), followed by MRSC (8.1%) and MRSA (1.6%). Floors represented the principal environmental reservoir, with significantly higher contamination odds than medical instruments (adjusted odds ratios [AOR] = 0.32; 95% confidence interval = 0.12–0.86; p = 0.024). The dermatological unit showed a six-fold higher risk of MRCoPS contamination than the medicine unit (AOR = 5.86; p = 0.027). All MRSC isolates carried SCCmec type V and displayed a consistent triple resistance pattern (gentamicin-clindamycin-erythromycin), while MRSP isolates exhibited diverse antibiograms and untypeable SCCmec elements. PFGE revealed clonal similarity (pattern A) between canine and environmental isolates, confirming the potential for nosocomial transmission. Conclusion: MRCoPS, particularly MRSP, were widely distributed and persistent in the VTH-CU environment, despite routine cleaning. The clonal overlap among environmental and canine isolates highlights potential cross-contamination within the hospital. Strengthened disinfection protocols, antimicrobial stewardship programs, and regular environmental surveillance are imperative to mitigate the spread of multidrug-resistant staphylococci. This study highlights the importance of integrating environmental, animal, and human infection control practices in veterinary facilities within the context of One Health. Keywords: coagulase-positive staphylococci, methicillin-resistant Staphylococcus pseudintermedius, nosocomial infection, One Health, staphylococcal cassette mec typing, veterinary hospital.