Identification of Bacteria Contaminating Musca domestica (Diptera: Muscidae) Collected from Animal Husbandries

Background: House flies (Musca domestica L.) may mechanically transmit many microorganisms to humans. Objectives: To identify bacteria contaminating Musca domestica (Diptera: Muscidae) collected from animal husbandries in province of Qom, Iran in the year of 2019. Methods: In the cross-sectional study, house flies were captured by plastic water bottle fly traps and insect nets from four districts of the Qom Province and were immediately transferred to the Department of Medical Entomology, School of Public Health in sterile glass containers, individually. The bacterial isolation of the surface and gut contents of the flies were separately performed by biochemical methods. To confirm Salmonella spp. and Shigella spp., antigen-antibody agglutination reactions were carried out by specific antisera. Results: A total of 23 bacterial species were identified from 160 house fly external surfaces and/or digestive tract were isolated. The most frequently isolated bacteria from the external body and the digestive tract of 160 flies were E. coli (73.8%) and P. aeruginosa (100%), respectively. The most frequently isolated bacteria were P. aeruginosa, Salmonella serogroup D, S. dysenteriae, E. coli, C. freundii, S. aureus, and S. epidermidis. Conclusions: House flies are important in the mechanical transmission of a different range of the pathogens. In addition, because of the geographical features of Qom and isolated pathogens, it seems that the possibility of mechanical disease transmission by the flies can be increased.