The occurrence, spatial and temporal distribution, and environmental routes of tetracycline resistance and integrase genes in Crassostrea virginica beds

► Bacterial communities of oyster beds and oysters carry multiply tetracycline resistance genes and integrons, which profiles vary both temporally and spatially between oysters and their environments. ► Oysters selectively accumulate bacterial hosts for particular tetracycline resistance genes and integrons in the mantle fluid. ► Rarely reported class 3 integrons dominate the integrons' profile in mantle fluid. ► The watershed is the main source of tetracycline resistance genes and integrons that most likely reached oyster beds with animal and municipal wastes as environmental carriers.