FREQUENCY AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF BACTERIA AND FUNGI ISOLATED FROM HOUSEHOLD REFRIGERATORS

Abstract

Refrigerators, though designed to preserve food, can harbor diverse microbial populations that contribute to food spoilage and pose health risks. This study aimed to monitor and identify pathogenic microorganisms present in household refrigerators and to evaluate their antimicrobial resistance profiles. A total of 100 swab samples were collected from three compartments (shelves, vegetable boxes, and egg trays) of domestic refrigerators in Faisalabad. Samples were cultured on selective and differential media and identified through colony morphology, Gram staining, and biochemical tests including catalase, oxidase, TSI, motility, and IMViC. Antimicrobial susceptibility was assessed using the Kirby-Bauer disk diffusion method following CLSI 2014 guidelines. The bacterial isolates included Bacillus spp. (17.3%), Staphylococcus aureus (8%), Micrococcus spp. (7.3%), Listeria spp. (3.3%), E. coli (14.7%), Klebsiella spp. (11.3%), Enterobacter spp. (10.6%), Pseudomonas aeruginosa (6%), Salmonella spp. (5.3%), Shigella spp. (5.3%), Citrobacter spp. (3.3%), Pantoea spp. (3.3%), Proteus vulgaris (2.7%), and Campylobacter spp. (1.3%). Fungal isolates included Penicillium spp. (45%), Aspergillus spp. (25%), Rhizopus spp. (20%), and Saccharomyces cerevisiae (10%). Alarmingly, gram-negative bacteria exhibited high resistance to ampicillin (93%), amoxicillin/clavulanic acid (72%), ceftazidime (69%), and cefepime (64%). Staphylococcus aureus was 92% resistant to both penicillin and amoxicillin/clavulanic acid. Amikacin and ciprofloxacin were the most effective antibiotics across all isolates. These findings emphasize the potential risk posed by household refrigerators as reservoirs of resistant pathogens, highlighting the need for better hygiene practices and public awareness.