Role of Clinical Microbiologists in Antimicrobial Stewardship Programs in Tertiary Hospitals in Enugu State

Antimicrobial stewardship programs (ASPs) are evidence-based interventions designed to optimize antibiotic use, reduce resistance selection pressure, and improve patient outcomes. Clinical microbiologists are recognized as essential members of ASP teams, yet their role in Nigerian tertiary hospitals is poorly characterized. This study investigated the involvement and perceived impact of clinical microbiologists in ASPs operating across three tertiary hospitals in Enugu State, South East Nigeria. A mixed-methods design incorporating structured questionnaires, key informant interviews, and retrospective review of ASP intervention records was employed. Quantitative data on antibiotic consumption trends, blood culture positivity rates, and resistance rate changes before and after ASP implementation were extracted from medical records. Results indicated that only one of three hospitals had a formally structured ASP. In that hospital, introduction of microbiologist-led weekly antibiogram reviews and prospective audit with feedback reduced broad-spectrum antibiotic consumption by 24 percent over 18 months. Clinical microbiologists in the other two hospitals reported advisory roles without dedicated ASP structures. Barriers to microbiologist participation included heavy diagnostic workloads, limited staffing, and insufficient institutional recognition of ASP roles. These findings confirm the underutilization of clinical microbiology expertise in hospital antibiotic governance in South East Nigeria and call for institutionalization of microbiologist-led ASP structures across tertiary healthcare facilities. Keywords: antimicrobial stewardship, clinical microbiology, antibiotic consumption, tertiary hospital, Enugu.