Burden, Epidemiology, and Risk Factors for Healthcare-Associated Infections in Intensive Care Units Across Nigerian Tertiary Hospitals

Healthcare-associated infections in intensive care units represent the most severe and costly patient safety challenge in Nigerian tertiary hospitals, yet their epidemiological burden, causative organisms, and independent risk factors have not been systematically characterised across the country's six geopolitical zones. This study investigates the burden, epidemiology, and risk factors for healthcare-associated infections in intensive care units at twelve federal tertiary hospitals, two per geopolitical zone, over a 24-month prospective surveillance period. A prospective cohort surveillance design is applied, enrolling all patients admitted to study intensive care units for 48 hours or more (projected n = 2,800). Healthcare-associated infection definitions follow the WHO Healthcare-Associated Infection Prevention and Control criteria. Clinical, microbiological, and exposure data are collected through standardised case report forms at admission, daily during stay, and at discharge or death. Microbiological isolates undergo antibiogram testing and whole-genome sequencing for resistance gene profiling in a subset of multi-drug resistant organisms. Multivariate Cox proportional hazards regression models, accounting for time-varying exposures, identify independent risk factors for healthcare-associated infection acquisition. Antimicrobial resistance burden is described using defined daily doses per 100 patient-days. The Process-Outcome Quality Model and Epidemiological Triad provide the analytical framework. Original contributions include the first national multi-centre intensive care unit healthcare-associated infection incidence estimate in Nigeria, a validated risk prediction score, and a genomically characterised antimicrobial resistance landscape with direct antibiotic stewardship implications. Keywords: healthcare-associated infections, intensive care units, antimicrobial resistance, epidemiology, Nigeria.