Emergence of a novel hybrid plasmid carrying bla NDM-5 in a Klebsiella pneumoniae isolate producing KPC-2

<title>Abstract</title> <p> Acquisition of plasmid-borne <italic>bla</italic> _NDM gene in KPC-2 producing <italic>Klebsiella pneumoniae</italic> ( <italic>K. pneumoniae</italic> ) largely threatening clinical effectiveness of ceftazidime-avibactam, an effective regiment for treating infections caused by serine carbapenemase producing pathogens. This study reports an extensively drug-resistant (XDR) <italic>K. pneumoniae</italic> clinical strain namely KP234 co-harboring carbapenemase genes <italic>bla</italic> _NDM−5 and <italic>bla</italic> _KPC−2 . The phenotype and genotype of <italic>K. pneumoniae</italic> KP234 were investigated by antimicrobial susceptibility testing, phenotypic detection for carbapenemase gene, PCR, conjugation assay, and whole genome sequencing (WGS). Bioinformatics analysis were used to uncover the genetic structures of its plasmid p234-NDM-5 and p234-KPC-2. KP234 displayed an XDR phenotype that only susceptible to colistin. WGS analysis identified five plasmids including plasmid p234-NDM-5 harboring <italic>bla</italic> _NDM−5 and plasmid p234-KPC-2 harboring <italic>bla</italic> _KPC−2 in KP234. Comparative genetic analysis revealed p234-NDM-5, a hybrid IncFIA/FIB/FIC plasmid, probably originated from an <italic>bla</italic> _NDM−5 -bearing plasmid pNDM4 (CP083878) in <italic>Escherichia coli</italic> . Further detailed sequence analysis showed p234-NDM-5 might be generated as a result of an ~ 37 kb p16HN-263 (CP045264) derived fragment integrated into a transposase encoding gene between the gene encoding recombinase family protein and <italic>pemk</italic> gene on plasmid pNDM4. Additionally, this 37 kb insertion segment present in p234-NDM-5 undergone rearrangement events compare with its corresponding region on plasmid p16HN-263, indicating further evolution of such <italic>bla</italic> _NDM -bearing plasmids in KPC-2 producing <italic>K. pneumonia</italic> . Our findings highlight further dissemination of the <italic>bla</italic> _NDM−5 and <italic>bla</italic> _KPC−2 into a clinical isolate of KP234 and convergence with multiple resistance genes, which increases the risk of the emergence of XDR strains and threatens the treatment of <italic>Enterobacterales</italic> bacterial infections. </p>