Methicillin‑Resistant Staphylococcus aureus in a Central Nigeria Tertiary Hospital

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of both health care- and community- associated infections worldwide and do present therapeutic challenges to beta-lactam antibiotics and other antibiotics due to the development of multidrug resistance. Aim: This study was carried out to determine the prevalence and antibiotic susceptibility profile of MRSA among patients at National Hospital Abuja with a view to providing information that will guide rational choice of antimicrobial agents in the empirical therapy of its infections. Materials and Methods: Between April 2014 and August 2015, clinical samples of patients submitted to Medical Microbiology laboratory of the hospital were processed and all Staphylococcus aureus isolates recovered, using standard laboratory methods. They were subjected to antibiotic susceptibility testing using the modified Kirby Bauer disc diffusion technique with zones of inhibition interpreted according to the Clinical and Laboratory Standard Institute (CLSI) guidelines. Methicillin resistance was determined using cefoxitin disc diffusion. Other clinical data of the patients were gathered along for analysis. Results: Of the 360 S. aureus isolates recovered, 97 (26.9%) were MRSA. All (100%) the MRSA isolates were susceptible to vancomycin, 88 (90.7%) to imipenem and 71 (73.2%) to clindamycin. All (100%) the MRSA isolates were resistant to penicillin, 85(88.0%) to tetracycline, 61 (62.9%) to ciprofloxacin, 58 (60.0%) to erythromycin and 52 (53.6%) to gentamycin. The MRSA strains showed higher resistance rate than MSSA strains to all tested antibiotics. Multidrug resistance was found in 68.0% of the MRSA strains. Conclusion: There was high prevalence of MRSA with high rates of resistance to commonly used anti-staphylococcal antimicrobials, and a significant proportion of these MRSA isolates were multi-drug resistant. Vancomycin is the best choice for empiric treatment of suspected MRSA infections. Routine screening of clinical S. aureus isolates for methicillin resistance, regular surveillance studies as well as institution of infection control measures and antibiotic stewardship programme are recommended.