AUTHOR=Huang Jiangqing , Zhang Shengcen , Zhao Zhichang , Chen Min , Cao Yingping , Li Bin 

TITLE=Acquisition of a Stable and Transferable blaNDM-5-Positive Plasmid With Low Fitness Cost Leading to Ceftazidime/Avibactam Resistance in KPC-2-Producing Klebsiella pneumoniae During Treatment

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.658070

DOI=10.3389/fcimb.2021.658070

ISSN=2235-2988

ABSTRACT=<p>The emergence and prevalence of carbapenem-resistant <italic>Enterobacteriaceae</italic> (CRE) have drawn worldwide attention. Ceftazidime/avibactam (CAZ/AVI) gives us a valuable alternative strategy to treat CRE infections. Unfortunately, CAZ/AVI resistance could occur during CAZ/AVI treatment. The CAZ/AVI-resistant Carbapenem-resistant <italic>Klebsiella pneumoniae</italic> (CR-KP) (KP137060) and earlier CAZ/AVI-susceptible isolate (KP135194) from the same hospitalized patient were collected at Fujian Medical University Union Hospital between October and November 2019. In this study, CAZ/AVI MICs of CAZ/AVI-susceptible and -resistant isolates (KP135194 and KP137060) were 4 mg/L and 128 mg/L, respectively; and the two isolates had the same antibiotic resistance pattern to other carbapenems. Two strains were then submitted for whole-genome sequencing and bioinformatic analysis. <italic>ompK36</italic> was not detected in two isolates. No mutation was observed in <italic>bla</italic><sub>KPC-2</sub>, <italic>ompK35</italic> and <italic>ompK37</italic> in this study and there was no significant difference of the expression in <italic>bla</italic><sub>KPC-2</sub>, <italic>ompK35</italic> and <italic>ompK37</italic> between the two isolates (<italic>p</italic>&gt;0.05). Two isolates were sequence type 11 and harbored <italic>bla</italic><sub>KPC-2</sub>, <italic>bla</italic><sub>SHV-182</sub> and <italic>bla</italic><sub>TEM-1B</sub>. Compared with KP135194, KP137060 harbored an additional <italic>bla</italic><sub>NDM-5</sub> positive plasmid. <italic>bla</italic><sub>NDM-5</sub> gene could be successfully transferred into <italic>E. coli</italic> J53 at a conjugation frequency of 1.14×10<sup>-4</sup>. Plasmid stability testing showed that <italic>bla</italic><sub>KPC-2</sub>- and <italic>bla</italic><sub>NDM-5</sub>-harboring plasmids were still stably maintained in the hosts. Growth assay and growth competition experiments showed there was no significant difference in fitness cost between two CR-KP isolates. Our study described the acquisition of a <italic>bla</italic><sub>NDM-5</sub>-harboring plasmid leading to resistance to ceftazidime/avibactam in KPC-2-producing <italic>Klebsiella pneumoniae</italic> during treatment. This phenomenon deserves further exploration.</p>