MICROBIOLOGICAL EXAMINATION OF MUSCA DOMESTICA (HOUSEFLY) AS AN AGENT FOR THE SPREAD OF ANTIBIOTIC-RESISTANT BACTERIA IN CALABAR, CROSS RIVER STATE, NIGERIA

This study investigated the role of Musca domestica (houseflies) in the carriage and potential dissemination of antibiotic-resistant bacteria in Calabar, Cross River State, Nigeria. Fifty adult houseflies were collected by random sampling from homes, markets, schools and hospitals and examined using conventional microbiological methods. Bacterial isolates were identified by Gram staining and biochemical tests, and antimicrobial susceptibility was assessed using the disc diffusion method. Five bacterial groups were recovered: Staphylococcus aureus (14/50; 28%), Escherichia coli (12/50; 24%), Clostridium spp. (10/50; 20%), Salmonella spp. (8/50; 16%) and Shigella spp. (6/50; 12%). Markets yielded the highest number of isolates (17/50; 34%), followed by hospitals (15/50; 30%), homes (10/50; 20%) and schools (8/50; 16%). Gram-negative isolates accounted for 26/50 (52%) and Gram-positive isolates for 24/50 (48%). The susceptibility profile showed substantial resistance to several commonly used antibiotics, particularly Septrin, Sparfloxacin and Amoxicillin, with resistance also observed to other agents. These findings support the public-health importance of houseflies as mechanical carriers of potentially resistant bacteria and underscore the need for improved sanitation, fly control, antimicrobial stewardship and routine surveillance. Because the study was based on phenotypic testing and a small, geographically limited sample, molecular confirmation of resistance genes is recommended in future work.