Complete Sequence of pCY-CTX, a Plasmid Carrying a Phage-Like Region and an IS Ecp1 -Mediated Tn 2 Element from Enterobacter cloacae

A plasmid pCY-CTX carrying a phage-like backbone from an extensively drug-resistant Enterobacter cloacae strain Guangzhou-ECL001 (previously known as CY01) was identified in this study. By Illumina MiSeq 2 × 250-bp paired-end sequencing, de novo assembly, and PCR, full sequence of pCY-CTX was obtained. Plasmid pCY-CTX was a circular plasmid with a length of 116,700 bp, harboring 136 putative open reading frames with the average G + C content of 50.8%. The backbone of pCY-CTX showed high identity to previously reported phage-like plasmid pHCM2 and phage SSU5. In addition, pCY-CTX contained a distinctive IS Ecp1 -mediated Tn 2 region with two resistance genes bla TEM-1 and bla CTX-M-3 . Transposition unit “IS Ecp1- bla CTX-M-3 - orf477 ” was inserted into the Tn 2 structure, dividing Tn 2 into two parts. This represents the first identification of a plasmid carrying a phage-like backbone and a distinctive IS Ecp1 -mediated Tn 2 region within bla TEM-1 and bla CTX-M-3 in clinical E. cloacae . The finding of phage-like regions located in plasmids provides a new perspective in gene transfer associated with antimicrobial resistance.