Bacterial Contamination and Antimicrobial Susceptibility Patterns of Isolates from Door Handles at a Public University Campus in Uganda: A Cross-Sectional Study

Abstract Door handles are among the most frequently touched surfaces in institutional settings and can act as fomites for the transmission of pathogenic and antimicrobial-resistant bacteria, yet contamination on university campuses in low-resource settings remains poorly characterised. We conducted a laboratory-based cross-sectional study to determine the prevalence, bacteriology and antimicrobial susceptibility profile of contaminants on door handles at Mbarara University of Science and Technology (MUST) City Campus, Uganda. Using stratified random sampling across hostels, lecture rooms, toilets, laboratories and offices, 100 door handles were swabbed in the evening using a standardised technique and processed within 24 hours. Isolates were cultured on blood and MacConkey agar, identified by colony morphology, Gram stain and standard biochemical tests, and tested for antimicrobial susceptibility by the Kirby-Bauer disc diffusion method per CLSI guidelines. Of the 100 door handles sampled, 53 (53.0%) yielded bacterial growth, producing 59 isolates across five species, including three cases of polymicrobial contamination. Contamination was highest on toilet handles (68.2%) and lowest on laboratory handles (20.0%). Gram-positive cocci predominated (89.8%), led by Staphylococcus hyicus (47.5%) and Staphylococcus aureus (40.7%); Klebsiella pneumoniae (8.5%), Hafnia sp . (1.7%) and Staphylococcus saprophyticus (1.7%) were also recovered. Antimicrobial susceptibility testing revealed high resistance to azithromycin (61.0%), tetracycline (44.1%) and penicillin (40.7%), while gentamicin (8.5% resistance) and chloramphenicol (20.3% resistance) retained the greatest activity. Cefixime and ceftriaxone resistance among Gram-negative isolates (tested only on n=6) suggested possible extended-spectrum beta-lactamase production. These findings demonstrate that door handles in a university setting, including non-clinical, community environments, harbour a substantial burden of bacterial contamination and antimicrobial resistance, with implications for infection prevention policy in academic institutions in low- and middle-income countries. Routine surface disinfection, reinforced hand hygiene, and prudent antimicrobial use are recommended, alongside further studies incorporating molecular confirmation and minimum inhibitory concentration testing.