Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Department of Microbiology, Fujita Health University, Toyoake, Aichi, Japan.
J Antimicrob Chemother. 2018 Feb 1;73(2):373-376. doi: 10.1093/jac/dkx389.
fosA3 is the most commonly reported plasmid-mediated fosfomycin resistance gene among Enterobacteriaceae.
To identify the origin of fosA3.
The chromosome of Kluyvera georgiana clinical strain YDC799 was fully sequenced with single-molecule real-time sequencing. Comparative genetic analysis was performed for K. georgiana YDC799, K. georgiana type strain ATCC 51603 and representative fosA3-carrying plasmids. fosA genes were cloned in Escherichia coli to confirm function.
K. georgiana YDC799 harboured fosA (designated fosAKG) and blaCTX-M-8 on the chromosome. The genetic environments surrounding fosA3 and bounded by IS26 were nearly identical with the corresponding regions of K. georgiana YDC799 and ATCC 51603. The amino acid sequence of FosAKG from YDC799 and K. georgiana ATCC 51603 shared 99% and 94% identity with FosA3, respectively. Cloned FosAKG conferred fosfomycin resistance with an MIC of >1024 mg/L for E. coli.
The plasmid-mediated fosA3 gene was likely mobilized from the chromosome of K. georgiana by an IS26-mediated event.
fosA3 是肠杆菌科中报告最多的质粒介导的磷霉素耐药基因。
鉴定 fosA3 的起源。
采用单分子实时测序技术对产酸克雷伯菌临床株 YDC799 的染色体进行全序列测序。对产酸克雷伯菌 YDC799、产酸克雷伯菌标准株 ATCC 51603 和具有代表性的 fosA3 质粒进行比较遗传分析。将 fosA 基因克隆到大肠杆菌中以确认功能。
产酸克雷伯菌 YDC799 染色体上携带 fosA（命名为 fosAKG）和 blaCTX-M-8。fosA3 及其周围的 IS26 被包围的遗传环境与产酸克雷伯菌 YDC799 和 ATCC 51603 的相应区域几乎相同。YDC799 和 ATCC 51603 产酸克雷伯菌 FosAKG 的氨基酸序列与 FosA3 分别具有 99%和 94%的同源性。克隆的 FosAKG 使大肠杆菌对磷霉素的 MIC 大于 1024mg/L 而具有抗药性。
fosA3 基因可能是通过 IS26 介导的事件从产酸克雷伯菌染色体上转移而来的。
