Comparative Evaluation of Methicillin-resistant Staphylococcus aureus (MRSA) Isolates from Hospital and Community Settings in Nigeria

The ability of Staphylococcus aureus to resist cefoxitin amongst other antibiotics has made it a significant public health problem in hospital and community settings. In this study, the occurrence of cefoxitin (methicillin) resistant S. aureus (MRSA) in the University of Calabar Medical Center and community was evaluated after obtaining informed consent and ethical approval. A total of 150 clinical samples collected from participants seen at the Medical Center and community settings were analyzed. Isolates were identified and characterized following standard microbiological procedures while antimicrobial sensitivity was carried out using the disc diffusion method. A total of 42 S. aureus strains were isolated, out of which 27(64.3%) were from the Medical Center and 15(35.7%) were from the community samples. Antimicrobial susceptibility testing of test isolates showed high resistance to the test antibiotics with cefoxitin being the highest (60%). Out of the 60% MRSA recovered, 74.1% (20/27) were from University of Calabar Medical Center while 33.3% (5/15) were from the Community. In addition, MRSA isolates from both locations also showed resistance to other antibiotics including amoxicillin, ampicillin+cloxacillin, levofloxacin, norfloxacin and erythromycin. This study revealed a high occurrence of Hospital-setting methicillin-resistant S. aureus (HA-MRSA) strains compared to Community-setting methicillin-resistant S. aureus (CA-MRSA) strains. This study further revealed that MRSA were multi-drug resistant. Thus, good infection control practices including identifying and treating MRSA carriers, moderate use of antibiotics and hand washing could reduce the burden associated with MRSA-related infections. To further establish and characterize multidrug resistant S. aureus strains, genotypic studies may be employed.