Prevalence of Escherichia coli O157:H7 From House Flies (Diptera: Muscidae) and Dairy Samples in North Central Florida

Efficient detection of enterohemorrhagic Escherichia coli O157:H7 is important to monitor the safety of food products obtained from cattle, and it has been primarily accomplished by analyzing manure samples by selective cultivation techniques, PCR, and ELISA. As each technique suffers from different biases, there may be value in using multiple methods and samples to increase detection efficiency. Difficulties associated with cattle manure sampling can be circumvented by isolation of E. coli O157:H7 from house flies, Musca domestica (L.), which present as an important vector for spreading diseases. Thus, isolation of pathogens directly from house flies provides information about the potential human health impact that house fly dispersal can have because of pathogen distribution. House flies can disperse from dairy farms, where E. coli O157:H7 endemically thrive in cattle, to restaurants where food is prepared and served. Here, we report that detecting E. coli O157:H7 in house flies was 2.7 times more frequent than in manure from nearby dairy farms. Flies appear to offer a promising alternative in efforts to detect E. coli O157:H7 in dairy farms, restaurants, processing plants, and other establishments.