Staphylococcus aureus And MRSA Carriage Among A Large Veterinary Academic Community: Are Veterinarians Bacteria Proof?

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is considered a serious threat that requires continuing public health monitoring and effective prevention activities. Occupational safety among high risk populations, specifically veterinary personnel, has been poorly researched and requires further understanding to improve safety and health protection in the workplace.

Methods: The objective of this study was to compare the prevalence and risk factors associated to S. aureus (SA)/MRSA carriage between hospital (HP) and non-hospital (NHP) personnel belonging to the same veterinary community. A large-scale cross-sectional study was performed at a comprehensive academic veterinary medical center and its associated college of veterinary medicine. Samples were collected concurrently from humans (hospital and college personnel), patients (canines) and the hospital environment. Antimicrobial susceptibility testing, SCCmec typing, PFGE typing, and molecular epidemiological analysis were used to characterize and analyze all SA/MRSA isolates.

Results: Overall, 25.7% (52/202) and 2.0% (4/202) of the community was nasally colonized with SA and MRSA respectively. When analyzed by HP and NHP, the former was 1.55 times (p-value >0.5) more likely to be colonized with MRSA than NHP. Among HP, residents and senior veterinary students were the most prevalent groups. Senior students were 3 times (p-value 0.03) more likely to carry SA than 3^rd year students. Lack of hand washing, glove use while handling patients, and covering visible hand lesions were identified as risk factors for SA carriage. In fact, even though 91% of HP self-reported washing their hands between patients, those that didn’t were 4.3 times (p-value 0.03) more likely to be colonized with SA. It was also observed that 10% of SA and 33% of MRSA strains found in the personnel were clonal or closely related to those detected in the hospital environment. Additionally, both community and hospital-acquired MRSA strains were observed circulating in this community.

Conclusion: These findings highlight the importance of personal hygiene and compliance with infectious controls measurements for the prevention of SA/MRSA colonization among personnel with high occupational exposure.