Zhou Y, He Y Y, Wang F W, He P, Hou S P, Tao X, Zhang X Q, Hu Y S, Wu X W
Microbiology Test Laboratory, Guangzhou Center for Disease Control and Prevention, Guangzhou 510440, China.
School of Medicine, Jinan University, Guangzhou 510440, China.
Zhonghua Yu Fang Yi Xue Za Zhi. 2022 Feb 6;56(2):178-184. doi: 10.3760/cma.j.cn112150-20210712-00670.
To analyze the enterotoxins, enterotoxin genes, drug resistance and molecular typing of 41 isolates from 2 food-borne illness outbreaks on 21 August and 27 September 2020 in Guangzhou. A total of 41 isolates from 2 outbreaks were analyzed by multilocus sequence typing (MLST) and typing. The enterotoxins typing and the enterotoxin genes of the isolates were analyzed by ELISA and PCR, respectively. The antimicrobial susceptibility of the isolates was performed by disc diffusion. 21 isolates were characterized using whole genome sequencing (WGS). Based on the whole genome single nucleotide polymorphism (SNP), the phylogenetic tree was constructed by Snippy. 41 isolates were divided into 2 types by MLST and typing: ST6-t701 and ST7-t091. 2 ST7-t091 isolates were identified as methicillin-resistant (MRSA). 25 ST7-t091 isolates and 14 ST6-t701 isolates were methicillin-sensitive (MSSA), and were resistant to 7 and 6 antibiotics, respectively. All isolates were positive for by PCR. WGS revealed all 21 isolates carried , , , , , , , , virulence genes. The results showed the isolates contained an immune evasion cluster type D which located in bacteriophage ϕSa3. The SNP phylogenetic tree showed 2 MRSA ST7-t091 were constituted a separate clade from the 12 MSSA ST7-t091 isolates and 7 ST6-t701 isolates showed high similarity to each other. Base on the results of phylogenetic analysis, the 2 food-borne illness outbreaks occurred on 21 August and 27 September 2020 are caused by the combination of the MRSA ST7-t091 strain and the MSSA ST7-t091 strain, and the MSSA ST6-t701 strain, respectively. All isolates have high level of antibiotic resistance and carry high virulent genes.
分析2020年8月21日和9月27日广州两起食源性疾病暴发中41株分离株的肠毒素、肠毒素基因、耐药性及分子分型。通过多位点序列分型(MLST)和分型对两起暴发中的41株分离株进行分析。分别采用酶联免疫吸附测定(ELISA)和聚合酶链反应(PCR)分析分离株的肠毒素分型和肠毒素基因。采用纸片扩散法检测分离株的抗菌药敏性。使用全基因组测序(WGS)对21株分离株进行特征分析。基于全基因组单核苷酸多态性(SNP),通过Snippy构建系统发育树。41株分离株通过MLST和分型分为2种类型:ST6-t701和ST7-t091。2株ST7-t091分离株被鉴定为耐甲氧西林金黄色葡萄球菌(MRSA)。25株ST7-t091分离株和14株ST6-t701分离株为甲氧西林敏感金黄色葡萄球菌(MSSA),分别对7种和6种抗生素耐药。所有分离株PCR检测均为阳性。WGS显示所有21株分离株均携带、、、、、、、、毒力基因。结果显示分离株含有位于噬菌体ϕSa3中的D型免疫逃避簇。SNP系统发育树显示2株MRSA ST7-t091与12株MSSA ST7-t091分离株构成一个独立分支,7株ST6-t701分离株彼此高度相似。基于系统发育分析结果,2020年8月21日和9月27日发生的两起食源性疾病暴发分别由MRSA ST7-t091菌株与MSSA ST7-t091菌株以及MSSA ST6-t701菌株组合引起。所有分离株均具有高水平的抗生素耐药性并携带高毒力基因。