Healthcare associated infections (HAI): Insights into epidemiology, microbiology, and diagnostics

Healthcare associated infections remain a major global health concern because they increase illness, mortality, hospital stay, and healthcare costs. This review provides an updated synthesis of recent evidence on the epidemiology, microbiology, diagnostics, and prevention of healthcare associated infections. These infections arise from patient susceptibility, invasive procedures, antibiotic overuse, contaminated equipment, and poor infection control practices. Device associated infections such as catheter associated urinary tract infection, central line associated bloodstream infection, ventilator associated pneumonia, and surgical site infection are common and often involve multidrug resistant pathogens. Biofilm formation on devices and hospital surfaces creates persistent reservoirs that promote resistance spread. Advances in automated culture systems, rapid molecular assays, metagenomics, and whole genome sequencing improve detection and surveillance. This article integrates evidence from 2020 to 2025 to provide a multidisciplinary framework for understanding and controlling HAIs.