Transcriptome and microbiome analyses of the mechanisms underlying antibiotic-mediated inhibition of larval development of the saprophagous insect Musca domestica (Diptera: Muscidae)

Abstract

Antibiotics are designed to treat bacterial infections in humans and animals; however, the overuse of various antibiotics and consequent contamination in the environment can have adverse effects on aquatic, soil, and saprophytic organisms. The house fly, an important decomposer in ecosystems, has been used for bioconversion of human and animal waste. Vermireactors have been used to remove antibiotics from waste for pollution control, but the effects of antibiotics on fly larvae are unclear. In the present work, we aimed to reveal the mechanism underlying the effects of antibiotics on larval growth in house flies at the transcriptome and microbiome levels and the relationships between genes and the microbiota. Observation of house flies after antibiotic exposure showed that gentamicin sulfate and levofloxacin hydrochloride inhibited larval development to a greater extent than amoxicillin. Transcriptome analysis revealed that biological pathways related to protein synthesis and the metabolism of fatty acids, pentose, and glucuronate were significantly enriched in flies exposed to gentamicin sulfate and levofloxacin hydrochloride. Crucial genes in these pathways were identified as candidates for future study. Microbiome analysis revealed three key bacteria that were closely correlated with gentamicin sulfate and levofloxacin hydrochloride exposure. The correlation network between the differentially expressed genes and bacteria identified an important microbic effector, Pseudomonas and its associated genes. This work will improve the knowledge about the mechanism underlying the effects of antibiotics on the larval development of house flies in the environment and provide guidance for improving the application of house fly bioconversion.