Point surveillance of Staphylococcus aureus carriage among medical staff in Infectious Diseases Hospital, Kuwait

Objective: To investigate the carriage of Staphylococcus aureus among doctors and nurses in Infectious Diseases Hospital, Kuwait, following the detection of 3 cases of methicillin-resistant S. aureus (MRSA). Materials and Methods: A total of 260 nasal and throat swabs were obtained from 19 doctors and 111 nurses and cultured for the carriage of S. aureus. Forty-three S. aureus were identified based on their growth characteristics on mannitol-salt agar, catalase and tube coagulase and DNA hydrolysis. The isolates were tested for susceptibility to antibacterial agents and typed by phage typing; plasmid analysis and pulsed-field electrophoresis were carried out to determine their relatedness. Results: Of the 19 doctors, 4 (21%) had nasal carriage while only 1 of them had a throat carriage. Sixteen (14.4%) nurses carried S. aureus in their noses and 20 (18%) in their throats. The combined nasal carriage rate for both doctors and nurses was 15.8%, and combined throat carriage was 16.6%. None of them carried MRSA. The isolates were resistant to penicillin G (90%), tetracycline (23.3%), erythromycin (9.3%) and cadmium (100%). Typing of the isolates showed a variety of phage types, plasmid and pulsed-field gel electrophoresis patterns. Discussion: None of the doctors or nurses carried MRSA. Typing of the methicillin-susceptible strains that they carried demonstrated that the S. aureus were different, indicating an absence of a dominant clone capable of spreading. It is important to maintain a low carriage of S. aureus among health-care workers. Copyright (C) 2003 S. Karger AG, Basel.