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Front. Microbiol. | doi: 10.3389/fmicb.2019.02678

Emergence of NDM-1-and CTX-M-3-producing Raoultella ornithinolytica in human gut microbiota

 Wang Shuang1, Xu L. Chen1,  Chi X. Hui2, Li Yan1, Kou Z. Qiang1, Hou P. Bin1, Xie H. Jie3*, Bi Z. Wang1* and  Zheng B. Wen4*
  • 1Shandong Center for Disease Control and Prevention, China
  • 2School of Public Health, Shandong University, China
  • 3Shandong Institutes for Food and Drug Control, China
  • 4State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, China

Raoultella ornithinolytica is an opportunistic pathogen of the Enterobacteriaceae family, and has been implicated in nosocomial infections in recent years. The aim of this study was to characterize a carbapenemase-producing R. ornithinolytica isolate and three extended-spectrum β-lactamase (ESBL)-producing R. ornithinolytica isolates from stool samples of adults in a rural area of Shandong Province, China. The species were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rDNA sequence analysis. Antimicrobial susceptibility test showed that all 4 isolates were multidrug-resistant (MDR). The whole genome sequence (WGS) of these isolates was determined using an Illumina HiSeq platform, which revealed MDR-related genes. The S1 nuclease-pulsed-field gel electrophoresis (S1-PFGE) was used to characterize the plasmids carried by the R. ornithinolytica isolates. The blaNDM-1 and blaCTX-M-3 genes were probed using Southern blotting, which confirmed the location of both genes on the same plasmid with molecular weight of 336.5-398.4 kb. The transferability of blaNDM-1 and blaCTX–M was also confirmed by conjugation assays. Finally, BLAST analysis of both genes showed that mobile genetic elements were associated with the spread of drug resistance genes. Taken together, we report the presence of conjugative blaNDM-1 and blaCTX-M plasmids in R. ornithinolytica isolates from healthy humans, which indicate the possibility of inter-species transfer of drug resistance genes. To the best of our knowledge, this is the first study to isolate and characterize carbapenemase-producing R. ornithinolytica and ESBL-producing R. ornithinolytica isolates from healthy human hosts.

Keywords: Raoultella ornithinolytica, carbapenemase, extended-spectrum β-lactamase, bla NDM-1, Bla CTX-M, Whole-genome sequencing

Received: 31 Jul 2019; Accepted: 05 Nov 2019.

Copyright: © 2019 Shuang, Chen, Hui, Yan, Qiang, Bin, Jie, Wang and Wen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Prof. Xie H. Jie, Shandong Institutes for Food and Drug Control, Jinan, 250101, Shandong Province, China,
Dr. Bi Z. Wang, Shandong Center for Disease Control and Prevention, Shandong, China,
Mx. Zheng B. Wen, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang Province, China,