The problem of bacterial drug resistance has become a global problem. Acquisition of exogenous antimicrobial resistant genes through horizontal gene transfer is the main reason for the emergence and dissemination of antimicrobial resistant bacteria. Integrons are mobile gene element that can capture and express drug resistance genes through site-specific recombination which were first proposed in 1989 and play an important role in bacterial drug resistance. Integrons allow bacteria to quickly respond to changes in selective pressure by recombining resistance gene cassettes of varying sizes. In order to increase the selective advantage of bacteria, the expression of integrons and gene cassettes are strictly regulated to reduce the adaptive cost to host bacteria. This paper reviews the concept, structure, and function of integrons and the mechanism of the expression regulation of integron-cassette system.

Drug resistance; Integrons; Gene cassette; Expression regulation; Progress