Nasal Carriage of Methicillin-resistant Staphylococcus aureus in Healthcare Workers

Abstract

Objectives : Methicillin-resistant Staphylococcus aureus (MRSA) colonization is considered to be a significant risk factor for MRSA infections in patients. The anterior nares is the most frequent carriage site for S. aureus. This study was undertaken to ascertain a point prevalence of MRSA colonization among healthcare workers working in intensive care units (ICUs) of a tertiary teaching hospital. Materials and Methods : A total of 270 ICU staffs (145 doctors and 125 nurses) working in 6 different ICUs were included, and swabs of the anterior nares were taken from the staffs for culture. Mannitol-salt agar, catalase and coagulase tests were used to identify S. aureus and cefoxitin disk was used to detect methicillin resistance. All procedures were followed as directed in CLSI guidelines. Results : The colonization of S. aureus was found in 58 of 270 staffs (21.5%). Thirteen of 58 isolates of S. aureus were methicillin resistant, so the prevalence of MRSA carriage among ICU healthcare workers was 4.8%: 2.1% (3/145) for doctors and 8% (10/125) for nurses. The highest rate of nasal carriage of MRSA was seen in cardiovascular care unit whereas chest surgery ICU had no prevalence of MRSA at all. Discussion : The annual prevalence of MRSA infection was about 78% in ICU of our hospital, but the nasal carriage of MRSA among healthcare workers in ICU was 4.8%. The prevalence of MRSA colonization was rather higher in nurses than doctors which could be due to the frequent contact and close relation with the patients. Therefore, more attention and annual follow-up surveillance together with molecular studies will be needed to have infection-control, to minimize MRSA prevalence and to clarify the endemic clonality if an outbreak of MRSA infection occurs within the hospital.