Reduced ceftazidime and ertapenem susceptibility due to production of OXA-2 in Klebsiella pneumoniae ST258

Alina Iovleva, Roberta T. Mettus, Christi L. McElheny, Mustapha M. Mustapha, Daria Van Tyne, Ryan K. Shields, A. William Pasculle, Vaughn S. Cooper, Yohei Doi

研究成果: Article査読

3 被引用数 (Scopus)

抄録

BACKGROUND: OXA-2 is a class D β-lactamase that confers resistance to penicillins, as well as narrow-spectrum cephalosporins. OXA-2 was recently reported to also possess carbapenem-hydrolysing activity. Here, we describe a KPC-2-encoding Klebsiella pneumoniae isolate that demonstrated reduced susceptibility to ceftazidime and ertapenem due to production of OXA-2. OBJECTIVES: To elucidate the role of OXA-2 production in reduced ceftazidime and ertapenem susceptibility in a K. pneumoniae ST258 clinical isolate. METHODS: MICs were determined by the agar dilution method. WGS was conducted to identify and compare resistance genes between isolates. Expression of KPC-2 was quantified by quantitative RT-PCR and immunoblotting. OXA-2 was expressed in Escherichia coli TOP10, as well as in K. pneumoniae ATCC 13883, to define the relative contribution of OXA-2 in β-lactam resistance. Kinetic studies were conducted using purified OXA-2 enzyme. RESULTS: K. pneumoniae 1761 belonged to ST258 and carried both blaKPC-2 and blaOXA-2. However, expression of blaKPC-2 was substantially reduced due to an IS1294 insertion in the promoter region. K. pneumoniae 1761, K. pneumoniae ATCC 13883 and E. coli TOP10 carrying blaOXA-2-harbouring plasmids showed reduced susceptibility to ertapenem and ceftazidime, but meropenem, imipenem and cefepime were unaffected. blaOXA-2 was carried on a 2910 bp partial class 1 integron containing aacA4-blaOXA-2-qacEΔ1-sul1 on an IncA/C2 plasmid, which was not present in the earlier ST258 isolates possessing blaKPC-2 with intact promoters. Hydrolysis of ertapenem by OXA-2 was confirmed using purified enzyme. CONCLUSIONS: Production of OXA-2 was associated with reduced ceftazidime and ertapenem susceptibility in a K. pneumoniae ST258 isolate.

本文言語English
ページ(範囲)2203-2208
ページ数6
ジャーナルThe Journal of antimicrobial chemotherapy
74
8
DOI
出版ステータスPublished - 01-08-2019

All Science Journal Classification (ASJC) codes

  • 薬理学
  • 微生物学(医療)
  • 感染症
  • 薬理学(医学)

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