Open Access

Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii

  • Authors:
    • Shu‑Zhen Xiao
    • Hai‑Qing Chu
    • Li‑Zhong Han
    • Zhe‑Min Zhang
    • Bing Li
    • Lan Zhao
    • Liyun Xu
  • View Affiliations

  • Published online on: July 22, 2016     https://doi.org/10.3892/mmr.2016.5538
  • Pages: 2483-2488
  • Copyright: © Xiao et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

The aim of the study was to investigate the resistant mechanisms and homology of imipenem-resistant Acinetobacter baumannii (A. baumannii). A total of 46 non-duplicate imipenem‑resistant A. baumannii clinical isolates were collected from three tertiary hospitals between July, 2011 and June, 2012. The minimal inhibitory concentrations (MICs) of antimicrobial agents were determined using the agar dilution method. Phenylalanine‑arginine β-naphthylamide was used to detect the presence of the efflux pump-mediated resistant mechanism. Polymerase chain reaction was employed to amplify genes associated with drug resistance, including β‑lactamase genes, efflux pump genes and outer membrane protein gene CarO. A few amplicons were randomly selected and sequenced. Multilocus sequence analysis (MLST) was employed in typing A. baumanni. A. baumannii was resistant to imipenem, simultaneously showing resistance to several other antimicrobials. In addtition, 13 A. baumannii were found to mediate drug resistance through operation of the efflux pump. Of the various drug resistance genes tested, blaOXA‑51 was present in 46 isolates, blaOXA‑23 gene was present in 44 isolates and blaNDM gene was found in only one strain. Other drug resistant‑associated genes, including blaKPC, blaIMP, blaOXA-24, blaOXA‑58, blaSHV, blaGIM and blaVIM were not detected. Mutation of adeS and outer membrane protein gene CarO were found in a few of the imipenem‑resistant isolates. The MLST analysis revealed that all 46 clinical isolates were clustered into 11 genotypes and the most frequent genotype was ST208. In conclusion, β‑lactamase genes, genes involved in efflux pump and mutation of outer membrane protein encoding gene may be important in mediating imipenem resistance in A. baumannii. Of the 11 different genotypes, ST11 was shared by the majority of A. baumannii, which may be due to horizontal transfer of patients from hospitals.
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September-2016
Volume 14 Issue 3

Print ISSN: 1791-2997
Online ISSN:1791-3004

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Copy and paste a formatted citation
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Spandidos Publications style
Xiao SZ, Chu HQ, Han LZ, Zhang ZM, Li B, Zhao L and Xu L: Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii. Mol Med Rep 14: 2483-2488, 2016
APA
Xiao, S., Chu, H., Han, L., Zhang, Z., Li, B., Zhao, L., & Xu, L. (2016). Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii. Molecular Medicine Reports, 14, 2483-2488. https://doi.org/10.3892/mmr.2016.5538
MLA
Xiao, S., Chu, H., Han, L., Zhang, Z., Li, B., Zhao, L., Xu, L."Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii". Molecular Medicine Reports 14.3 (2016): 2483-2488.
Chicago
Xiao, S., Chu, H., Han, L., Zhang, Z., Li, B., Zhao, L., Xu, L."Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii". Molecular Medicine Reports 14, no. 3 (2016): 2483-2488. https://doi.org/10.3892/mmr.2016.5538