House flies are cosmopolitan insects with worldwide distribution among both urban and agricultural settings. House flies also are demonstrated reservoirs and transmitters of both pathogenic and nonpathogenic microbes. Surveys of house flies by our group have shown that fly sex, environmental niche and time influence bacterial carriage in terms of bacterial abundance and community composition. Bacteria from flies captured at agricultural sites such as cattle production facilities (e.g. dairies and feedlots) have shown widespread antimicrobial resistance and in most cases multi-drug resistance, both to human and veterinary antimicrobials. Flies therefore not only pose a risk as environmental sources of bacteria, but also can be used for xenosurveillance to assess the incidence and prevalence of bacteria that are of human and animal health concern.
