Global distribution and genetic characterization of bla_OXA-positive plasmids in Escherichia coli

In recent years, the emergence of bla_OXA-encoding Escherichia coli (E. coli) poses a significant threat to human health. Here, we systematically analyzed the global geographic distribution and genetic characteristics of 328 bla_OXA-positive E. coli plasmids based on NCBI database. Twelve bla_OXA variants have been discovered, with bla_OXA−1 (57.93%) being the most common, followed by bla_OXA−10 (11.28%) and bla_OXA−48 (10.67%). Our results suggested that bla_OXA-positive E. coli plasmids were widespread in 40 countries, mainly in China, the United States, and Spain. MLST analysis showed that ST2, ST43, and ST471 were the top three host STs for bla_OXA-positive plasmids, deserving continuing attention in future surveillance program. Network analysis revealed a correlation between different bla_OXA variants and specific antibiotic resistance genes, such as bla_OXA−1 and aac (6’)-Ib-cr (95.79%), bla_OXA−181 and qnrS1 (87.88%). The frequent detection of aminoglycosides-, carbapenems- and even colistin-related resistance genes in bla_OXA-positive plasmids highlights their multidrug-resistant potential. Additionally, bla_OXA-positive plasmids were further divided into eight clades, clade I-VIII. Each clade displayed specificity in replicon types and conjugative transfer elements. Different bla_OXA variants were associated with specific plasmid lineages, such as bla_OXA−1 and IncFII plasmids in clade II, and bla_OXA−48 and IncL plasmids in clade I. Overall, our findings provide a comprehensive insight into bla_OXA-positive plasmids in E. coli, highlighting the role of plasmids in bla_OXA dissemination in E. coli.