Nasal carriage of methicillin resistant Staphylococcus aureus among health care workers at Al Shifa hospital in Gaza Strip

BACKGROUND: Nasal carriage of Staphylococcus aureus among hospital personnel is a common cause of hospital acquired infections. Emergence of drug resistant strains especially methicillin resistant S. aureus (MRSA) is a serious problem in hospital environment. Therefore, the aim of this study was to determine the nasal carriage rate of S. aureus and MRSA among Health Care Workers (HCWs) at Al Shifa Hospital, the major hospital in Gaza Strip. METHODS: A cross sectional study was conducted on 200 HCWs. Nasal swabs were collected during February — April 2015, and cultured on blood and mannitol salt agar. The isolates were identified as S. aureus based on morphology, coagulase test, DNase test and mannitol salt agar fermentation. Disk diffusion antibiotic susceptibility tests were performed according to the guidelines of the Clinical and Laboratory Standards Institute. MRSA were confirmed by detection of the mecA gene by PCR. RESULTS: Out of the 200 healthcare workers, 62 (31%) carried S. aureus, of which 51 (82.3%) were MRSA. Therefore, 25.5% of all HCWs were identified as MRSA carriers. MRSA carriage rate was highest among nurses (30.4%) whereas the carriage rate among doctors was (16%). The majority of MRSA carriers were workers of internal medicine department and surgical wards (41.3 and 35% respectively). Out of the 51 MRSA isolates identified by oxacillin disc resistance, 40 were confirmed by PCR targeting the mecA gene. Penicillin showed the highest rate of resistance among MRSA and MSSA isolates (100%). CONCLUSIONS: The high rate of nasal MRSA carriage among healthcare workers found in this study is alarming and highlights the need for adjusted infection control measures to prevent MRSA transmission from HCWs to the vulnerable patient.