江西省首起中式凉拌菜引起一例孕妇李斯特菌病的溯源研究

Tracing the source of the first listeriosis case in a pregnant woman caused by Chinese cold dishes in Jiangxi Province

目的对江西省首起中式凉拌菜引起一例孕妇李斯特菌病进行溯源分析。方法采用描述性研究方法对李斯特菌病患者开展流行病学调查,采用临床检测方法和国家标准GB 4789.30—2016方法对血液、食品样品中的单核细胞增生性李斯特菌进行分离,并用生化、质谱方法对分离的菌株进行鉴定,菌株的分型和溯源分析使用脉冲场凝胶电泳、全基因组测序方法。结果流调结果显示,患者症状以发热为主,新生儿无感染,有每周进食一次中式凉拌菜的习惯。患者血培养鉴定结果为单核细胞增生性李斯特菌,现场对患者家进行的环境样本采样未检出单核细胞增生性李斯特菌,采集患者常去的熟食店销售的2份凉拌菜检出了该细菌。PFGE电泳分型显示患者分离株与食品分离株分型结果一致,全基因组测序结果菌株均为ST1型。结论中式凉拌菜存在引起孕妇李斯特菌病的风险,应加强监测,有关部门应加强对相关餐饮店的监管。

Objective This study aimed to trace the source of a listeriosis case in a pregnant woman linked to the consumption of Chinese cold dishes in Jiangxi Province.Methods A descriptive epidemiological investigation was conducted to gather patient information.Listeria monocytogenes strains from both food and blood samples were isolated using the national standard GB 4789.30—2016 methods and clinical test methods.The isolated strains were identified using biochemical and mass spectrometry methods.Subtyping and source tracing of the strains were performed using pulsed field gel electrophoresis and whole genome sequencing.Results The patient exhibited fever as the primary symptom of L.monocytogenes infection,while the fetus was not affected.The patient reported a weekly habit of consuming Chinese cold dishes.Blood culture from the patient yielded a strain of L.monocytogenes,whereas no L.monocytogenes strains were found in field samples collected from the patient’s home.However,the bacteria were detected and isolated from two Chinese cold dishes purchased from restaurants frequented by the patient.Pulsed-field gel electrophoresis typing confirmed complete consistency between the patient-isolated strains and those isolated from the food.Whole genome sequencing revealed that the strains belonged to the ST1 type.Conclusion The risk of listeriosis in pregnant women associated with Chinese cold dishes persists.Enhanced monitoring measures are warranted,and relevant authorities should intensify their supervision of associated restaurants.