Nosocomial infections and associated risk factors at two tertiary healthcare facilities in Lusaka and Copperbelt Provinces, Zambia

Background: Nosocomial infections are a serious public health problem affecting both developed and developing countries. They are caused mainly by multi-drug-resistant pathogens that limit treatment options, leading to high morbidity and mortality, longer hospital stays and increased costs of health care. This study aimed to evaluate nosocomial infections, risk factors and causative pathogens at two large teaching hospitals in Zambia. Material and methods: A yearlong hospital-based cross-sectional study was conducted from April 2020 to April 2021 at two large tertiary-level hospitals in Zambia. Hospitalised and out-patients with previous hospital contact were screened for nosocomial infections, followed by the collection of specimens (skin swabs, urine or sputum) for bacteriological culture and Polymerase Chain Reaction (PCR) amplification of 16S rRNA gene fragments. Nosocomial infections were defined according to the World Health Organization case definitions. Frequencies were estimated, and the association between the outcome variable (positive culture) and categorical predictor variables were analysed using the Chi-square test. Results: Eight hundred and forty-one clinical specimens (skin swabs, urine or sputum) were collected and analysed, 640 from the University Teaching Hospital in Lusaka and 201 from the Ndola Teaching Hospital in Ndola. Of these, 71.2% were from male, with only 28.8% from female patients. The median age was 50 years old. Catheter-associated urinary tract infections (57%) were the most common, followed by those from pressure sores (38.7%). The most frequently observed pathogens included Escherichia coli (17.8%), Pseudomonas aeruginosa (13.7%), Klebsiella pneumonia (5.6%) and Proteus vulgaris (5.5%). Conclusions: The hospital infection rate at the two urban tertiary hospitals was very high. Age over 65 years, male gender, presence of medical devices, presence of a wound, longer hospital stays, previous hospital contacts and low systolic blood pressure were associated with the risk of developing nosocomial infections. Despite improved infection control following the COVID-19 waves, nosocomial infections have remained a significant public health threat.