Genomic features and fitness cost of co-existence of and plasmids in ICU-derived pan-drug resistant .

BACKGROUD

The emergence of carbapenem-resistant (CRPA) co-producing KPC-2 and VIM-2 has increased the healthcare threats.

RESULTS

In this study, a CRPA strain 18102011, was isolated from the bile of a burn patient in ICU of China. Its whole genome was sequenced via the PacBio platform. The molecular characteristics of the genome were analyzed to assess the genetic environment of the carbapenemase genes and . Antimicrobial susceptibility, plasmid stability, bacterial growth curves, and plasmid conjugation were measured. Strain 18102011 exhibited a resistant pattern to all 23 antibiotics tested, which could be defined as a pan-drug resistant strain. Two plasmids were identified in this strain: the Inc mega-plasmid pP2011-1 carrying and the IncP6 plasmid pP2011-2 carrying . was located in the region of In2057 (a novel class 1 integron) that was inserted into pP2011-1, and the expression of the gene was increased by the PcW promoter located at the 5'-CS. For the gene, the core module Tn-IS- -ΔIS served as the platform in pP2011-2, and the expression of the gene was achieved via the P1 promoter located downstream of IS. This expression pattern resulted in MICs of 4,096 μg/mL of imipenem for both strain 18102011 and its transconjugant D2011. Both plasmids were stable in strain 18102011 and could be co-transferred to other strains.

CONCLUSION

This study raised concerns regarding the high stability and non-inferior fitness of - -CRPA, shed light on its genomic characteristics, and underscored the importance of continued surveillance of CRPA.