AUTHOR=Chen Qianqian , Zhou Wangxiao , Qian Changrui , Shen Kai , Zhu Xinyi , Zhou Danying , Sun Zhewei , Lu Wei , Liu Hongmao , Li Kewei , Xu Teng , Bao Qiyu , Lu Junwan 

TITLE=OXA-830, a Novel Chromosomally Encoded Extended-Spectrum Class D β-Lactamase in Aeromonas simiae

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.02732

DOI=10.3389/fmicb.2019.02732

ISSN=1664-302X

ABSTRACT=<p>The diversity of class D β-lactamases mediating resistance to β-lactams has been increasingly reported recently. In this study, a novel class D oxacillinase named OXA-830 was identified in a fully sequenced <italic>Aeromonas simiae</italic> strain, which was isolated from sewage discharged from a farm in southern China. OXA-830 shares the highest amino acid identity of 79.3% with an OXA-12-like variant named OXA-725. When expressed in <italic>E. coli</italic> DH5α, OXA-830 conferred resistance to penicillins and selected β-lactamase inhibitors but not to cephalosporins and carbapenems. Kinetic analysis of OXA-830 revealed a broad substrate profile including penicillins, cefazolin, cefoxitin, and ceftazidime but not carbapenems. The hydrolytic activity was significantly inhibited by sulbactam, followed by tazobactam, but was less effectively inhibited by clavulanic acid. The <italic>bla</italic><sub>OXA–</sub><sub>830</sub> gene was located on the <italic>A. simiae</italic> A6 chromosome and the <italic>bla</italic><sub>OXA–</sub><sub>830</sub>-related region was bracketed by a pair of perfect inverted repeats.</p>