Plasmidome analyses of Klebsiella pneumoniae coproducing blaKPC-2 and blaNDM-1 in Southern Brazil: Characterization of Mobile Genetic Elements.

Abstract

Objectives: Infections due to carbapenemase-producing Enterobacterales harboring more than one carbapenemase-encoding gene spreads mainly by plasmid and transposon mobilization.

Objectives: Analyze the mobile genetic elements carrying bla_KPC and bla_NDM of K. pneumoniae carbapenemase co-producers (KpKN).

Methods: K. pneumoniae isolates with reduced susceptibility to carbapenems were obtained from 2016 to 2023. To evaluate the genetic environment of KpKN, 22 isolates were selected for antimicrobial susceptibility testing and whole-genome sequencing (WGS).

Results: The bla_KPC-2 gene was carried mainly by IncN/IncFIB, a novel co-integrated plasmid in the Tn4401b transposon. The bla_NDM-1 was disseminated in the only two KpKN isolates recovered before 2020 by IncHI1B/IncFIB plasmid type, in the Tn3000 transposon. Noteworthy, isolates obtained since 2020 showed the bla_NDM-1 gene carried by IncA/C in an IS26-flanked pseudo-composite transposon containing ISCR1, which also had genes that confer resistance to sulfonamides, aminoglycosides, macrolides, quinolones, amphenicols, tetracyclines, rifampicin, sulfonamide, and trimethoprim. The isolates belong mainly to ST11 and ST16.

Conclusions: The plasmid and transposon changes during the different periods could be related to higher dissemination of the bla_NDM-1 and the large number of resistance genes present in the IS26-flanked transposon may have increased the co-selection of this plasmid through the wide use of antimicrobials during the pandemic.