Comparative genomic analysis of plasmids harboring -like genes in .

The emergence and spread of carbapenem-resistant (CRKP) is a serious medical problem worldwide. Acquired OXA-48-like carbapenemases encoded by plasmids are important causes of carbapenem resistance in . To explore the links between plasmids and -like genes in , we systematically analyzed the variants of -like plasmid replicon types, phylogenetic patterns, geographic distribution, conjugative transfer regions, and the genetic environments surrounding -like of 191 -like-harboring plasmids, which were identified from 4451 plasmids of downloaded from GenBank. Our results showed that seven different variants of -like genes were identified from the 191 -like-harboring plasmids in , with , , and being highly prevalent. In , was mainly carried by the composite transposon Tn located on IncL/M-type conjugative plasmids, which were mainly geographically distributed in Switzerland, Germany, and China. In , the a gene was mainly carried by 6.1-kb ColKP3-type mobilizable plasmids, which were mainly isolated in India. In , was mainly carried by a group of 50-kb ColKP3-IncX3 hybrid conjugative plasmids and a group of small ColKP3-type mobilizable plasmids with lengths of 5.9-9.3 kb, the former was sporadically discovered in China, South Korea, India, and Czech Republic, while the latter was almost all isolated in India. In addition, five -harboring 65.9-kb IncL plasmids of isolated in Spain were found to have the genetic context of more complicated than that of -harboring IncL/M-type plasmids, with two copies of IS inserted both upstream and downstream of -. These findings enhance our understanding of the genetic diversity of -like-harboring plasmids in .