Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shen Zhen Research Institute, Shenzhen, P. R. China.
Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.
J Antimicrob Chemother. 2021 Mar 12;76(4):950-956. doi: 10.1093/jac/dkaa545.
To investigate the prevalence and genetic contexts of the blaCTX-M-14 gene harboured by foodborne isolates of Vibrio spp. in China.
A total of 1856 Vibrio spp. isolates collected from raw meat and shrimp samples in Guangdong Province of China were screened for blaCTX-M-14 by PCR. The blaCTX-M-14-positive isolates were characterized by MIC, PFGE, MLST, conjugation, S1-PFGE and Southern blotting and WGS using Illumina and Nanopore platforms.
A total of 35 (1.9%) Vibrio isolates were positive for blaCTX-M-14, including 33 Vibrio parahaemolyticus strains and two Vibrio alginolyticus strains. MLST showed that most of the blaCTX-M-14-bearing isolates could be assigned into two major STs, with ST163 being more prevalent (n = 23), followed by ST180 (n = 6). Whole-genome analysis of these 35 isolates revealed that the blaCTX-M-14 gene was associated with ISEcp1 in the upstream region, of which 32 blaCTX-M-14 genes were located in the same loci of chromosome I, 1 blaCTX-M-14 gene was located in a novel chromosomal integrative conjugative element (ICE) belonging to the SXT/R391 family and 2 blaCTX-M-14 genes were located in the same type of plasmid, which belonged to the IncP-1 group. Conjugation experiments showed that only the plasmid-borne blaCTX-M-14 gene could be transferred to the recipient strain Escherichia coli J53.
The emergence of the novel ICE and IncP-1 plasmids has contributed to the variable genetic contexts of blaCTX-M-14 among strains of Vibrio spp. and facilitated the horizontal transfer of such genes between Vibrio spp. and other zoonotic pathogens, resulting in a rapid increase in the prevalence of blaCTX-M-14-bearing bacterial pathogens worldwide.
调查中国食源性副溶血性弧菌携带 blaCTX-M-14 基因的流行情况和遗传背景。
采用 PCR 方法对广东省采集的 1856 株副溶血性弧菌进行 blaCTX-M-14 检测。对 blaCTX-M-14 阳性菌进行 MIC、PFGE、MLST、接合、S1-PFGE 和 Southern 印迹分析及 Illumina 和 Nanopore 平台的 WGS。
共检出 35 株（1.9%）blaCTX-M-14 阳性副溶血性弧菌，包括 33 株副溶血性弧菌和 2 株 Alg 群副溶血性弧菌。MLST 分析显示，携带 blaCTX-M-14 基因的副溶血性弧菌分离株主要分为两个 ST 型，其中 ST163 更为常见（n=23），其次是 ST180（n=6）。对这 35 株菌进行全基因组分析发现，blaCTX-M-14 基因位于 ISEcp1 上游，其中 32 个 blaCTX-M-14 基因位于染色体 I 相同位置，1 个 blaCTX-M-14 基因位于 SXT/R391 家族的新型染色体整合性接合元件（ICE）中，2 个 blaCTX-M-14 基因位于相同类型的质粒上，属于 IncP-1 组。接合实验表明，只有质粒携带的 blaCTX-M-14 基因可转移至受体菌株大肠杆菌 J53。
新型 ICE 和 IncP-1 质粒的出现导致了 blaCTX-M-14 基因在副溶血性弧菌菌株间的遗传背景多样化，并促进了此类基因在副溶血性弧菌与其他人畜共患病病原体之间的水平转移，导致全球 blaCTX-M-14 携带细菌病原体的流行率迅速上升。
