Maggots: an easily overlooked indicator insect of the distribution and receptor bacteria of ARGs

Antibiotic resistance genes (ARGs) are a new type of pollutant in the environment, and insects serve as the medium for their spread. Maggots, as an important organism in polluted environments, can come into contact with, acquire, and transfer ARGs; however, the patterns indicating the spread of ARGs remain unclear. Here, we showed that tet A, sul 2, amp , and km were widely distributed in maggots in chicken farm, pond, trash can, and hospital. Soil and food were important sources of ARGs in maggots. Sul 2 was found in the head, chest, and abdomen. Both maggots and adult houseflies have ARGs. Feeding experiments firstly showed that the conjugative transfer of ARGs mediated by plasmids occurred in maggots. Providencia rustigianii and Providencia alcalifaciens in Proteobacteria were the main receptor bacteria of ARGs in maggots. Maggots can serve as new indicators of ARG contamination, and it is of great significance for preventing and controlling the spread of ARGs.