Prevalence and Antibiotic Resistance Profiles of Hospital-acquired and Community-acquired Methicillin-resistant Staphylococcus aureus Isolates in Edo State, Nigeria
Otobo, Onyeka Queen *
Department of Microbiology, Faculty of Life Sciences, Ambrose Alli University, Ekpoma, Edo State, Nigeria.
Okompu, Oluwafunke Moyinjesu
Department of Family Medicine, Federal Medical Centre, Asaba, Delta State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an important antimicrobial-resistant pathogen in hospital and community settings.
Aims: To determine the prevalence of hospital-acquired MRSA (HA-MRSA) and community-acquired MRSA (CA-MRSA), compare their antibiotic susceptibility patterns, and determine their multiple antibiotic resistance (MAR) indices.
Study Design: A cross-sectional comparative study.
Place and Duration of Study: Irrua Specialist Teaching Hospital (ISTH), Irrua, and Ekpoma community, Edo State, Nigeria, from January to July 2023.
Methodology: A total of 620 samples were collected, including 310 nasal swab, wound swab, and fomite samples from doctors, nurses, patients, cleaners, and fomites in 14 departments of ISTH, as well as 310 nasal swabs from apparently healthy individuals in Ekpoma community. The samples were cultured on Mannitol Salt Agar and isolates presumptively identified as Staphylococcus aureus were tested on Oxacillin Resistant Screening Agar Base using 1 μg oxacillin discs for confirmation. Susceptibility testing was conducted using the Kirby–Bauer disc diffusion method for vancomycin, linezolid, cloxacillin, ciprofloxacin, gentamicin, tetracycline, and erythromycin.
Results: The overall MRSA prevalence was 22% (133/620), with HA-MRSA prevalence at 27% (82/310) and CA-MRSA prevalence at 17% (51/310). Fomites yielded the highest HA-MRSA proportion (32%), followed by cleaners (24%), nurses (19%), patients (13%), and doctors (12%). Markets (30%) and motor parks (27%) had the highest CA-MRSA prevalence. All isolates (100%) were sensitive to vancomycin and linezolid, while 96% of both groups were resistant to cloxacillin. HA-MRSA showed higher resistance to ciprofloxacin (41% vs 20%), gentamicin (45% vs 35%), and erythromycin (26% vs 6%) compared to CA-MRSA. MAR index ranged from 0.2–0.4 for HA-MRSA and 0.1–0.2 for CA-MRSA.
Conclusion: HA-MRSA isolates exhibited higher antibiotic resistance and MAR indices than CA-MRSA, indicating antibiotic overuse in hospital settings. Strengthened antibiotic stewardship and infection-control measures are advocated.
Keywords: Methicillin-resistant Staphylococcus aureus, hospital-acquired MRSA, community-acquired MRSA, antimicrobial resistance, nasal carriage, antibiotic susceptibility, antibiogram, multiple antibiotic resistance index