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Abstract
Background: Hospital fomites act as reservoirs for pathogenic microorganisms and contribute substantially to the transmission of healthcare-associated infections (HAIs). Staphylococcus aureus, including methicillin-resistant strains (MRSA), is among the most clinically significant organisms recovered from such surfaces because of its capacity for biofilm formation and antimicrobial resistance. This study determined the prevalence, biofilm-forming potential, and antimicrobial resistance profile of S. aureus isolated from high-touch fomites at a tertiary care hospital in Islamabad, Pakistan.
Methods: A hospital-based, descriptive cross-sectional study was conducted at the Federal General Hospital, Islamabad. A total of 120 swab samples were collected by convenience sampling from high-touch surfaces and equipment across the Emergency, Medical, Gynecology/Labor, Pediatrics and Operation Theatre/Intensive Care Unit departments. Isolates were cultured on blood agar and identified as S. aureus by Gram staining, catalase and coagulase reactions, mannitol fermentation on Mannitol Salt Agar, and DNase activity. Biofilm formation was assessed qualitatively by the tube adherence method, and antimicrobial susceptibility was determined by the Kirby–Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) criteria.
Results: S. aureus recovered from 69 of 120 samples (57.5%), of which (32.0%) were cefoxitin-resistant and therefore classified as MRSA. Contamination was highest in the Medical and Emergency departments and on mobile phones, side tables, oxygen masks/nebulizers, door handles, and the hands of medical personnel. Resistance was most frequent to ciprofloxacin (54%), followed by trimethoprim sulfamethoxazole (41%) and clindamycin (37%). No phenotypic resistance to vancomycin was detected by disk diffusion, although MIC-based confirmation was not performed and cannot therefore exclude vancomycin-intermediate or heteroresistant isolates. Most isolates were moderate (38.7%) or strong ( 28%) biofilm producers, and only (4.7%) were biofilm negative.
Conclusion: Hospital fomites at this facility harbor a high burden of biofilm-forming, multidrug-resistant S. aureus, including MRSA. These findings support the need for targeted environmental surveillance, expanded disinfection protocols for frequently handled items such as mobile phones and respiratory equipment, and reinforced antimicrobial stewardship to limit the risk of nosocomial transmission.