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).


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.


CONCLUSIONS
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.
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Department of Microbiology, Infectious Diseases Hospital, Kuwait University, Safat, Kuwait.
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Grover
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D001434:Bacteriophage Typing; D002353:Carrier State / Q000175:diagnosis / Q000453:epidemiology*; D024881:Drug Resistance, Bacterial; D006801:Humans; D007730:Kuwait / Q000453:epidemiology; D008403:Mass Screening; D008505:Medical Staff, Hospital; D009296:Nasal Cavity / Q000382:microbiology; D009741:Nursing Staff, Hospital; D010614:Pharynx / Q000382:microbiology; D010957:Plasmids / Q000235:genetics; D013203:Staphylococcal Infections / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*