Microbial interactions of necrophagous flies and their impact on bacterial transmission

Abstract

Flies are commonly found in environments that contain large quantities of microorganisms. However, they also frequently interact with humans, potentially initiating the transmission of diseases. In order to investigate the roles in which flies are involved in disease transmission, we used Illumina NGS MiSeq 16s targeted DNA sequencing and bioinformatic analysis to compare the microbiomes of flies and decomposing rat tissues over periods of time following exposure. Sequencing results were analyzed for presence of the 2017 World Health Organization (WHO) priority list antibiotic-resistant pathogens on Kraken database. Spread plate dilutions were also made to observe relationships between culturable bacteria on each of the samples. Sequence comparisons revealed variance in microbiomes between different time points, as well as between the flies and rat tissue. Higher varieties of bacteria were sequenced from the fly tissues than the rat tissues, while the rat tissue bacteria remained fairly constant in concentration ratios over time. Kraken database blast indicated the presence of at least 5 of the prioritized antibiotic-resistant pathogens on each of the samples. Spread plate dilutions showed larger amounts of cultured bacterial colonies on rat tissues than fly tissues, as well as an average decrease in bacterial concentrations over time. From this study, we concluded that the microbiomes of flies are significantly influenced by exposure to bacteria-rich food sources. We also saw evidence of antibiotic-resistant bacterial suppression on flies, though the means of suppression is still unclear.