Molecular Characterization of -Carrying in Henan Province of China.

Carbapenem-resistant (CRE) pose a serious threat to clinical management and public health. We investigated the molecular characteristics of 12 IMP-4 metallo-β-lactamase-producing strains, namely, 5 , 3 , 2 , and 2 . These strains were collected from a tertiary teaching hospital in Zhengzhou from 2013 to 2015. The minimum inhibitory concentration (MIC) results showed that each -positive isolate was multidrug-resistant (MDR) but susceptible to colistin. All of the belonged to ST167, two isolates belonged to ST396, and diverse ST types were identified in and . S1-PFGE, Southern blotting, and PCR-based replicon typing assays showed that the -carrying plasmids ranged from ∼52 to ∼360 kb and belonged to FII, FIB, HI2/HI2A, and N types. N plasmids were the predominant type (8/12, 66.7%). Plasmid stability testing indicated that the -carrying N-type plasmid is more stable than the other types of plasmids. Conjugative assays revealed that three of the -carrying N plasmids were transferrable. Complete sequence analysis of a representative N type (pIMP-ECL14-57) revealed that it was nearly identical to pIMP-FJ1503 (KU051710) (99% nucleotide identity and query coverage), an N-type -carrying epidemic plasmid in a strain. PCR mapping indicated that a transposon-like structure [IS IS] was highly conserved in all of the N plasmids. IS involved recombination events that resulted in variable structures of this transposon-like module in FII and FIB plasmids. The gene was captured by a -type integron In1589 on HI2/HI2A plasmid pIMP-ECL-13-46.