AUTHOR=Liu Lu , Feng Yu , Hu Yiyi , Kang Mei , Xie Yi , Zong Zhiyong 

TITLE=Klebsiella grimontii, a New Species Acquired Carbapenem Resistance

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02170

DOI=10.3389/fmicb.2018.02170

ISSN=1664-302X

ABSTRACT=<p><italic>Klebsiella grimontii</italic> is a newly identified species closely related to <italic>Klebsiella oxytoca</italic>, but carbapenem resistance was not identified in the species before. We found a carbapenem-resistant <italic>K. oxytoca</italic>-like clinical strain, WCHKG020121. The strain was subjected to whole genome sequencing using Illumina HiSeq X10. The precise species identification was established based on average nucleotide identity (ANI) and <italic>in silico</italic> DNA–DNA hybridization (isDDH) between strain WCHKG020121 and type strains of <italic>Klebsiella</italic> species. Antimicrobial resistance genes were identified from the genome sequence. The sequence of the <italic>bla</italic><sub>KPC-2</sub>-carrying plasmid was completed using PCR and Sanger sequencing. Conjugation experiments were performed to obtain the plasmid carrying <italic>bla</italic><sub>KPC-2</sub>. All <italic>K. grimontii</italic> genomes were retrieved from GenBank and were analyzed for antimicrobial resistance genes. Strain WCHKG020121 was resistant to imipenem and meropenem (MIC for both, 32 μg/ml) but was susceptible to colistin (1 μg/ml). Strain WCHKG020121 was initially identified as <italic>K. oxytoca</italic> using Vitek II but it actually belongs to <italic>K. grimontii</italic> as it had a 98.81% ANI and 83.4% isDDH value with <italic>K. grimontii</italic> type strain. Strain WCHKG020121 had <italic>bla</italic><sub>KPC-2</sub>; by contrast, none of other <italic>K. grimontii</italic> genomes carry any known carbapenemase genes. <italic>bla</italic><sub>KPC-2</sub> was carried by a 95,734-bp plasmid, designated pKPC2_020121, which contained two different FII(Y) replicons. pKPC2_020121 was closest (93% coverage, 99% identity) to <italic>bla</italic><sub>KPC-2</sub>-carrying plasmids from <italic>Enterobacter hormaechei</italic> recovered in 2014 at the same hospital. pKPC2_020121 was not self-transmissible, which could be explained by the absence of a conjugation essential gene, <italic>traY</italic>. In conclusion, we reported the first <italic>K. grimontii</italic> strain that produced the KPC carbapenemase. Carbapenem resistant <italic>K. grimontii</italic> may represent a new threat.</p>