bla CTX-M-98b , bla TEM-1, and rmtB genes, detected in Escherichia coli from a chicken isolate in China]]>

摘要

Abstract Recently, a novel variant of the CTX-M enzyme, CTX-M-98, was detected in Escherichia coli isolates from food animals. However, few plasmids carrying bla CTX-M-98 have been fully characterized. In this study, we sequenced the complete pHeBE7 plasmid, an 86,015-bp plasmid that contains the bla CTX-M-98b , bla TEM-1 , rmtB , and traT genes, using whole-genome sequencing. The backbone of pHeBE7 shows a high similarity ( 99%) to pMC-NDM, which carries the bla NDM-1 gene, however its mosaic regions remain relatively unique among sequenced plasmids. We discovered that a typical IS Ecp1 - bla CTX-M -IS 903 element in the mosaic region harbors the bla CTX-M-98b gene. Conjugation and growth competition assays indicate that pHeBE7 can be easily transmitted and that it confers a limited fitness cost to the recipient cell. The genetic characterization of pHeBE7 may improve our knowledge of how antibiotic resistance disseminates in enterobacteria. Highlights ? A plasmid pHeBE7 carried bla CTX-M-98b , bla TEM-1 , rmtB and traT gene, was completely sequenced. ? pHeBE7-like plasmids could spread between human and food animals of different geographic and isolated origins. ? Plasmid pHeBE7 could be transmitted effectively with low fitness cost. ]]>