Li W W, Guo Y C, Zhan L, Ma G Z, Yang Z S, Liu C W, Shen Z X, Wang D, Zhang X A, Song X H, Yu B, Jia H Y, Li X G, Zhang X L, Yang X R, Yang D J, Pei X Y
Department of Risk Surveillance, China National Center for Food Safety Risk Assessment, Beijing 100022, China.
Microbiology Laboratory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China.
Zhonghua Yu Fang Yi Xue Za Zhi. 2020 Feb 6;54(2):175-180. doi: 10.3760/cma.j.issn.0253-9624.2020.02.012.
To analyze the molecular characteristics of strains from ready-to eat food in China. A total of 239 strains isolated from ready-to-eat food in 2017, all strains underwent whole-genome sequencing (WGS) , and comparisons uncovered population structure derived from lineages, clonal complex, serogroups, antimicrobial susceptibility and virulence, which were inferred in silico from the WGS data. Core genome multilocus sequence typing was used to subtype isolates. All strains were categorized into three different lineages, lineage Ⅱ was the predominant types in food, and IIa was the main serogroups. CC8, CC101 and CC87 were the first three prevalent CCs among 23 detected CCs, accounting for 49.4%. Only 4.6% (11 isolates) of tested strains harbored antibiotic resistance genes, which were mostly trimethoprim genes (7 isolates, 2.9%). All strains were positive for LIPI-1, and only a part of strains harbored LIPI-3 and LIPI-4, accounting for 13.8% (33 isolates) and 14.2% (34 isolates), respectively. ST619 carried both LIPI-3 and LIPI-4. 51.5% (123 isolates) of strains carried SSI-1, and all CC121 strains harbored SSI-2. Different lineages, serogroups and CCs can be separated obviously through cgMLST analysis, and 24 sublineages were highly concordant with CCs. Ⅱa was the main serogroups in ready-to-eat food isolates in China; CC8, CC101 and CC87 were the prevalent CCs, and CC87 isolates was hypervirulent isolates, cgMLST method can be adopted for prospective foodborne disease surveillance and outbreaks detection.
分析中国即食食品中菌株的分子特征。2017年从即食食品中分离出239株菌株，所有菌株均进行了全基因组测序（WGS），通过比较揭示了源自谱系、克隆复合体、血清群、抗菌药物敏感性和毒力的群体结构，这些是根据WGS数据通过计算机推断得出的。采用核心基因组多位点序列分型对分离株进行亚型分析。所有菌株分为三个不同的谱系，谱系Ⅱ是食品中的主要类型，Ⅱa是主要血清群。CC8、CC101和CC87是23个检测到的CC中前三个流行的CC，占49.4%。仅4.6%（11株）的测试菌株携带抗生素抗性基因，主要是甲氧苄啶基因（7株，2.9%）。所有菌株的LIPI-1均为阳性，只有一部分菌株携带LIPI-3和LIPI-4，分别占13.8%（33株）和14.2%（34株）。ST619同时携带LIPI-3和LIPI-4。51.5%（123株）的菌株携带SSI-1，所有CC121菌株均携带SSI-2。通过cgMLST分析可以明显区分不同的谱系、血清群和CC，24个亚谱系与CC高度一致。Ⅱa是中国即食食品分离株中的主要血清群；CC8、CC101和CC87是流行的CC，CC87分离株是高毒力分离株，cgMLST方法可用于前瞻性食源性疾病监测和疫情检测。
