In silico characterization of bla OXA -carrying plasmids in Escherichia coli

To comprehensively understand the association between plasmids and bla OXA genes in Escherichia coli ( E. coli ), the variants of bla OXA , antimicrobial resistance genes (ARGs), host Sequence Types, conjugative transfer regions and geographic distribution of 328 bla OXA -positive plasmids in E. coli were investigated. The 328 plasmids were found to carry 341 bla OXA genes belonging to 12 types of bla OXA variants. bla OXA−1 (n = 190) and bla OXA−10 (n = 37) were the most prevalent bla OXA variants, followed by bla OXA−48 (n = 35) and bla OXA−181 (n = 33). The bla OXA−1 variant was mainly carried by the IncF plasmids, while the majority of bla OXA−10 was located on IncH plasmids in E. coli . The former was widely distributed worldwide, while the latter was mainly concentrated in Asia. In E. coli , the bla OXA−48 gene was mainly carried by IncL replicons, which was mainly isolated in Spain and Switzerland. Multi-locus sequence typing (MLST) analysis showed that ST2, ST43, and ST471 accounted for the majority of E coli carrying bla OXA -positive plasmids, which deserved long-term attention in monitoring system. ARGs analysis results showed that ARGs was highly diverse in E. coli plasmids carrying bla OXA , suggesting that the E. coli harboring bla OXA has been gradually developing into the super-bacteria. These findings demonstrate the importance of plasmids in OXA β-Lactamases transmission and propose the importance of monitoring these factors to better understand and control the occurrence of antibiotic resistance.