Epidemiology of Methicillin-resistant Staphylococcus aureus (MRSA) colonization in different health care associated workers

[[abstract]]Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a main cause of health care-associated disease burden. Health care workers (HCWs) have been identified as the source of MRSA in numerous outbreak investigations. Epidemiology of MRSA nasal colonization in a range of HCWs have been studied, and yet out-of-hospital health care providers have limited data. This study aims to characterize the risk factors and molecular epidemiologic characteristics of MRSA colonization in out-of-hospital health care providers and HCWs in a teritary hospital. Methods: This was a prospective study. Participants included out-of-hospital health providers such as Emergency Medical Technicians, paramedics, nurses working in the long term care facilities and in-hospital health care providers such as physicians and nurses. Swabs were obtained from nares and processed using standard laboratory techniques. Standard microbiologic methods were used to identify methicillin-susceptible S. aureus and MRSA. Molecular epidemiologic methods included pulsed-field gel electrophoresis, PCR detection of Panton-Valentine leukocidin, and SCCmec and multilocus sequence typing. Results: A total of 112 out-of-hospital health care providers and 137 in-hospital HCWs participated. The combined prevalence rate of MRSA was 7%. The majority of the MRSA colonization were in female (16/17, 94%) and in-hospital nurses (12/17, 71%). Five (29%) of the out-hospital providers had MRSA colonization. Nurses (OR: 9.33, 95% CI: 2.03–42.90) and clinical service year between 5 and 10 years (OR: 3.66, 95% CI: 1–13.67) had higher risk for MRSA colonization. Eight different strains of MRSA were identified by pulsed-field gel electrophoresis. The majority of the MRSA was SCCmec IV and V strains, three of which carried Panton-Valentine leukocidin. A unique ST typing 398 from a hospital nurse who ever traveled to Europe was identified in this study. Conclusion: The findings suggest that there is substantial colonization of MRSA among in-hospital and out-hospital health care providers. Implementations of infection control strategies should be applied high priority in those HCWs