IS6 family insertion sequences promote optrA dissemination between plasmids varying in transfer abilities

AbstractPlasmids are the primary vectors for intercellular transfer of the oxazolidinone and phenicol cross-resistance geneoptrA, while insertion sequences (ISs) are mobile genetic elements that can mobilize plasmid-borneoptrA intracellularly. However, little is known about how the IS-mediated intracellular mobility facilitates the dissemination of theoptrA gene between plasmid categories that vary in transfer abilities, including non-mobilizable, mobilizable, and conjugative plasmids. Here, we performed a holistic genomic study of 52optrA-carrying plasmids obtained from searches guided by the Comprehensive Antibiotic Resistance Database. Among the 132 ISs identified within 10 kbp from theoptrA gene in the plasmids, IS6 family genes were the most prevalent (86/132). Homologous gene arrays containing IS6 family genes were shared between different plasmids, especially between mobilizable and conjugative plasmids. All these indicated the central role of IS6 family genes in disseminating plasmid-borneoptrA. Thirty-three of the 52 plasmids were harbored byEnterococcus faecalis found mainly in humans and animals. By Nanopore sequencing and inverse PCR, the potential of the enterococcaloptrA to be transmitted from a mobilizable plasmid to a conjugative plasmid mediated by IS6 family genes was further confirmed inEnterococcus faecalis strains recovered from the effluents of anaerobic digestion systems for treating chicken manure. Our findings highlight the increased intercellular tra...
Source: European Journal of Applied Physiology - Category: Physiology Source Type: research