Research progress in a novel mobile RND efflux pump TMexCD-TOprJ

Abstract:

Antibiotics are considered one of the cornerstones of modern medicine. However, the abuse of antimicrobial agents, including antibiotics, has accelerated the emergence of super bacteria that can resist multiple antimicrobial agents. Resistance genes are the key factors leading to bacterial resistance and can be horizontally transmitted by mobile genetic elements (MGEs), such as plasmids, transposons, and insertion sequences, posing a serious threat to public health. In recent years, facing the outbreak of carbapenem-resistant and polymyxin-resistant bacteria, tigecycline has been regarded as the “last line of defense” against multiple drug-resistant bacterial infections in humans. Recently, a novel mobile efflux pump gene cluster tmexCD-toprJ, mainly existing in plasmids, was found. This gene cluster encodes resistance-nodulation-cell division (RND) efflux pumps, which can expel a variety of antibiotics, including tigecycline, out of bacteria, greatly enhancing the resistance of bacteria. The tmexCD-toprJ gene cluster has been horizontally transferred to humans, animals, and the environment by mobile elements such as plasmids, posing a serious threat to public health. However, research on the specific structure and functional mechanism of TMexCD-TOprJ remains to be carried out. This article systematically summarizes the distribution characteristics, transmission mechanisms, and efflux pump structures of tmexCD-toprJ and proposes measures to block its spread from the concept of One Health, offering a scientific basis for slowing down the dissemination of tmexCD-toprJ.