AUTHOR=Li Xi , Wang Weizhong , Jin Xi , Zhang Xiaofan , Zou Xuehan , Ma Qiang , Hu Qingfeng , Huang Haijun , Tu Yuexing 

TITLE=Emergence of Plasmids Co-Harboring Carbapenem Resistance Genes and tmexCD2-toprJ2 in Sequence Type 11 Carbapenem Resistant Klebsiella pneumoniae Strains

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.902774

DOI=10.3389/fcimb.2022.902774

ISSN=2235-2988

ABSTRACT=<sec><title>Objectives</title><p>To characterize two plasmids co-harboring carbapenem resistance genes and <italic>tmexCD2-toprJ2</italic> in carbapenem-resistant <italic>Klebsiella pneumoniae</italic> (CRKP) strains.</p></sec><sec><title>Methods</title><p>Two clinical CRKP strains were isolated and characterized by antimicrobial susceptibility testing, conjugation assays, whole-genome sequencing, and bioinformatics analysis.</p></sec><sec><title>Results</title><p>The two CRKP strains NB4 and NB5 were both resistant to imipenem, meropenem and tigecycline. Whole-genome sequencing revealed that two CRKP strains belonged to the ST11 type and carried multiple resistance genes. The <italic>tmexCD2-toprJ2</italic> clusters in both strains were located on the IncFIB(Mar)-like/HI1B-like group of hybrid plasmids, which co-harbored the metallo-β-lactamase gene <italic>bla</italic><sub>NDM-1</sub>. In addition, the co-existence of <italic>bla</italic><sub>NDM-1</sub> and <italic>bla</italic><sub>KPC-2</sub> and the presence of <italic>tmexCD2-toprJ2</italic> in CRKP strain NB5 was observed.</p></sec><sec><title>Conclusions</title><p>In this study, <italic>tmexCD2-toprJ2</italic> gene clusters were identified in two NDM-1-producing CRKP ST11 strains. These gene clusters will likely spread into clinical high-risk CRKP clones and exacerbate the antimicrobial resistance crisis. In addition, we detected the co-occurrence of <italic>bla</italic><sub>NDM-1</sub>, <italic>bla</italic><sub>KPC-2</sub> and <italic>tmexCD2-toprJ2</italic> in a single strain, which will undoubtedly accelerate the formation of a “superdrug resistant” bacteria. Hence, effective control measures should be implemented to prevent the further dissemination of such organisms in clinical settings.</p></sec>