Prevalence and multidrug resistance of nosocomial pathogens in surgical wards of tertiary hospital: The case of Queen Elizabeth Central Hospital in Malawi

Hospital-acquired infections remain a significant threat to patient safety, particularly in low and middle-income countries where antimicrobial resistance and limited infection prevention infrastructure exacerbate transmission. This study investigated the prevalence of nosocomial pathogens and antimicrobial resistance patterns in surgical wards of a tertiary hospital in Malawi. A cross-sectional study was conducted between January and April 2025, involving 26 clinical and environmental samples. Standard microbiological culture, biochemical identification, and antimicrobial susceptibility testing using the Kirby–Bauer disk diffusion method were performed according to EUCAST guidelines. Multidrug resistance was defined as resistance to three or more antimicrobial classes. Bacterial growth was detected in both patient and environmental samples, with isolates including Staphylococcus aureus, Acinetobacter spp., Pseudomonas aeruginosa, Klebsiella spp., Enterobacter spp., Proteus spp. and Citrobacter spp. Environmental contamination of hospital surfaces suggested potential cross-transmission. Antimicrobial susceptibility testing demonstrated highest effectiveness for aminoglycosides, particularly gentamicin and amikacin, while cephalosporins showed moderate activity. Carbapenems exhibited reduced effectiveness, with mean inhibition zones below resistance thresholds, indicating emerging resistance. Multidrug resistance was predominantly observed among Gram-negative organisms, with 81.8% classified as multidrug resistant, whereas only 15% of isolates were fully susceptible. A significant association between bacterial species and antimicrobial susceptibility patterns was observed. The findings indicate a high burden of multidrug-resistant Gram-negative pathogens and highlight hospital surfaces as potential reservoirs of infection. Reduced effectiveness of carbapenems raises concern regarding last-line treatment options. Strengthening antimicrobial stewardship, routine surveillance, and infection prevention measures is essential to mitigate healthcare-associated infections in resource-limited hospital settings.