AUTHOR=Ge Haoyu , Qiao Jie , Xu Hao , Liu Ruishan , Chen Ruyan , Li Chenyu , Hu Xinjun , Zhou Jiawei , Guo Xiaobing , Zheng Beiwen 

TITLE=First report of Klebsiella pneumoniae co-producing OXA-181, CTX-M-55, and MCR-8 isolated from the patient with bacteremia

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1020500

DOI=10.3389/fmicb.2022.1020500

ISSN=1664-302X

ABSTRACT=<p>The worldwide spread of carbapenem-resistant Enterobacteriaceae (CRE) has led to a major challenge to human health. In this case, colistin is often used to treat the infection caused by CRE. However, the coexistence of genes conferring resistance to carbapenem and colistin is of great concern. In this work, we reported the coexistence of <italic>bla</italic><sub>OXA-181</sub>, <italic>bla</italic><sub>CTX-M-55</sub>, and <italic>mcr-8</italic> in an ST273 <italic>Klebsiella pneumoniae</italic> isolate for the first time. The species identification was performed using MALDI-TOF MS, and the presence of various antimicrobial resistance genes (ARGs) and virulence genes were detected by PCR and whole-genome sequencing. Antimicrobial susceptibility testing showed that <italic>K. pneumoniae</italic> 5589 was resistant to aztreonam, imipenem, meropenem, ceftriaxone, cefotaxime, ceftazidime, levofloxacin, ciprofloxacin, gentamicin, piperacillin-tazobactam, cefepime, and polymyxin B, but sensitive to amikacin. S1-pulsed-field gel electrophoresis (PFGE) and Southern blotting revealed the <italic>mcr-8</italic> gene was carried on a ~ 138 kb plasmid with a conserved structure (IS<italic>903B</italic>-<italic>ymoA</italic>-<italic>inhA</italic>-<italic>mcr-8</italic>-<italic>copR</italic>-<italic>baeS</italic>-<italic>dgkA</italic>-<italic>ampC</italic>). In addition, <italic>bla</italic><sub>OXA-181</sub> was found on another ~51 kb plasmid with a composite transposon flanked by insertion sequence IS<italic>26</italic>. The <italic>in vitro</italic> conjugation experiments and plasmid sequence probe indicated that the plasmid p5589-OXA-181 and the p5589-mcr-8 were conjugative, which may contribute to the propagation of ARGs. Relevant detection and investigation measures should be taken to control the prevalence of pathogens coharboring <italic>bla</italic><sub>OXA-181</sub>, <italic>bla</italic><sub>CTX-M-55</sub> and <italic>mcr-8</italic>.</p>