The prevalence of Staphylococcus aureus colonization among Healthcare Workers at a Specialist Hospital in Saudi Arabia
Dr. Shamweel Ahmad Assistant Professor of Medical Microbiology and Consultant Microbiologist, Dept. of Clinical Laboratory Sciences, College of Medical Sciences in Al-Kharj, Al-Kharj University, Kingdom of Saudi Arabia
Objectives: The aim of this study was to determine the prevalence of the nasal carriage of Staphylococcus aureus among healthcare workers (HCWs) at a Specialist Hospital and to detect the antibiotic susceptibility of S. aureus.
Material and Methods: This cross-sectional study was conducted from January to April, 2007. Nasal swabs were taken from 352 randomly selected HCWs. The isolates were identified as S. aureus based on morphology, Gram stain, catalase test, coagulase test, and mannitol salt agar fermentation. The sensitivity of the isolates was carried out by the modified Kirby Bauer method.
Results: A total of 352 subjects comprising medical doctors, nurses, cleaners and the administrative staff of a Specialist Hospital, who worked in or frequently visited the nursery, maternity, paediatric, medical, surgery and intensive care wards during January to April 2007 were tested for the carriage of Staphylococci. 204 of them (58.0%) were males and 148(42%) were females. 313 (89%) subjects were doctors, nurses and cleaners and 39 (11%) were administrative personnel. Of the total 352 samples, S. aureus was isolated from 112 (31.8%) specimens. Of these 112 S. aureus isolates, 103 (92%) were found to be methicillin sensitive S. aureus (MSSA) and 9 (8%) were found to be methicillin resistant S. aureus (MRSA).The rate of S. aureus in males and females were 23.0% and 46.0%, respectively. The rate of S. aureus in the medical staff, nurses, cleaners and administrative personnel were 35.5% and 2.6%, respectively. The prevalence of the carriage was higher (30.1-33.4%) in young persons, i.e. less than 35 years than (6.8-15.7%) those aged 35-55 years or above. Most of the MSSA strains were susceptible to tested agents except penicillin, ampicillin, gentamicin and erythromycin. A majority of the MRSA isolates showed multiple drug resistance. All MSSA and MRSA isolates were fully sensitive to Vancomycin.
Conclusion: A high rate of the carriage of S.aureus in this hospital, with a large proportion of strains being resistant to penicillin and the isolation of MRSA strains from these carriers calls for periodic surveillance of nosocomial infections due to S.aureus and other important bacterial pathogens.