Antimicrobial Susceptibility Pattern of Staphylococcus aureus Isolated from Wound Infections in a Tertiary Hospital in Rivers State, South South Nigeria

Staphylococcus aureus is a leading cause of wound infections and has demonstrated increasing resistance to commonly used antimicrobial agents, including methicillin, posing significant therapeutic challenges. This study characterised the antimicrobial susceptibility pattern of S. aureus isolates from wound infections at the University of Port Harcourt Teaching Hospital, Rivers State, South South Nigeria. Wound swab samples were collected from 210 patients with infected wounds between January and September 2024. Bacterial isolation was performed using standard microbiological techniques on mannitol salt agar and blood agar, with identification confirmed through biochemical tests. Antimicrobial susceptibility testing was carried out using the Kirby-Bauer disc diffusion method, with interpretation based on the Clinical and Laboratory Standards Institute guidelines. Results identified S. aureus in 82 (39.0%) samples. Susceptibility testing revealed high resistance to penicillin (89.0%), ampicillin (85.4%), and tetracycline (73.2%). Methicillin-resistant S. aureus was detected in 35.4% of isolates. Sensitivity was highest for vancomycin (100%), linezolid (97.6%), and mupirocin (91.5%). Resistance patterns differed significantly between surgical and trauma wards. These findings call for strict antimicrobial stewardship programmes, routine susceptibility testing before prescribing, and enhanced infection control measures in clinical settings in Rivers State and similar tertiary institutions. Keywords: Staphylococcus aureus, antimicrobial susceptibility, wound infections, methicillin resistance, Rivers State