A Pandrug-Resistant Providencia Carrying Two blaIMP Carbapenemase-Encoding Genes Including blaIMP-69, a New blaIMP Variant, on a Newly Identified Worldwide-Distributed IncC Plasmid

Imipenemase (IMP) is a metallo-beta-lactamase that confers resistance to almost all beta-lactams. Identification of IMP genes is essential for understanding and combatting antibiotic resistance. In this study, we report a pandrug-resistant Providencia strain from a human rectal swab. This strain carried 2 bla(IMP) carbapenemase genes, bla(IMP-69) and bla(IMP-4). IMP-69 is a novel IMP variant with an amino acid substitution at A21T compared with IMP-8. bla(IMP-69) was found in a bla(IMP-69)-aacA4 array of an integron on a 165-kilobase (kb) IncC self-transmissible plasmid, whereas bla(IMP-4) was located in a bla(IMP-4)-qacG-aacA4-catB3 array of an integron on a 19-kb nonselftransmissible plasmid. Such coexistence has the potential to allow the generation of new, hybrid bla(IMP) variants by homologous recombination. The bla(IMP-69)-carrying IncC plasmid belonged to the core-genome plasmid multilocus sequence typing (cgPMLST) 3.5 type. We found that cgPMLST 3.5 IncC plasmids have been circulating worldwide for decades and may represent a common vehicle mediating the spread of antimicrobial resistance.