Molecular Detection of mecA gene among Methicillin Resistant Staphylococcus aureus Isolates from Clinical Samples in Sokoto, Nigeria

Abstract

Methicillin-resistant S. aureus (MRSA) infections have become a common problem in hospital and community-acquired infections. This study was aimed at detecting the presence of mecA gene among Methicillin Resistant Staphylococcus aureus Isolates from clinical samples obtained from 2 major hospitals in Sokoto, Northwestern Nigeria. A total of 95 non duplicate isolates were screened for confirmation using standard microbiological techniques. Antibiotic sensitivity testing was carried out by disc diffusion using Cefoxitin and resistant isolates were tested with different other antibiotics. All MRSA isolates were subjected to molecular analysis by detection of mecA gene based on PCR technique. Showed that, 42/95 (44.2%) were methicillin resistant. The most potent antibiotic was quinupristin/dalfopristin with 83.3% sensitivity followed by rifampicin with 81.0% and clindamycin with a 71.4%. The least activity was shown to be in fluoroquinolone antibiotic ciprofloxacin with 78.6% of the isolates demonstrating resistance followed by, tetracycline and gentamycin with 64.3%, 61.9% and 61.9% respectively. Most of the MRSA isolates were resistant to more than three antibiotics.PCR showed 36(85.7%) harbored the mecA gene. Although, polymerase chain reaction is the gold standard for determining Methicillin resistance through the detection of the mecA gene, the present study phenotypically established the presence of methicillin resistant S. aureus isolates that are mecA negative. Therefore, interpretation of MRSA detection strictly based on mecA detection should be done with care in the study area.