Detection of methicillin-resistant Staphylococcus aureus in nosocomial infections in Gaza Strip

Methicillin-resistant Staphylococcus aureus (MRSA) is considered to be one of the most important causative agents of nosocomial infections. The present study therefore aimed broadly at obtaining a snapshot of MRSA prevalence in Gaza Strip, as well as to examine the antibiotic resistance profile of such isolates. A total of 150 clinical isolates of S. aureus were identified from patients. Disk diffusion tests and a polymerase chain reaction (PCR) assay, based on detection of the mecA gene, were performed on each the isolates in order to identify MRSA strains. The PCR assay was considered as the "gold standard" and the disk diffusion tests were interpreted by comparison to this standard. The prevalence of methicillin resistance among S. aureus isolates was 22% (33 isolates). There were great variations between the antibiograms of methicillin-resistant and -sensitive S. aureus isolates. These variations were most evident for the beta-lactam antibiotics, although antibiotics other than beta-lactams also showed variations among the two types of S. aureus. The results showed that the conventional disk diffusion test using methicillin disks is highly reliable for detection of MRSA in hospital laboratories and that it can reach the specificity of the PCR assay.