Prevalence, Potential Virulence, and Genetic Diversity of Listeria monocytogenes Isolates From Edible Mushrooms in Chinese Markets.
Prevalence, Potential Virulence, and Genetic Diversity of Listeria monocytogenes Isolates From Edible Mushrooms in Chinese Markets.
复制标题
中国市场食用菌中单增李斯特菌的流行情况、潜在毒力和遗传多样性
DOI：
10.3389/fmicb.2018.01711
复制
发表时间：
2018
影响因子：
5.2
通讯作者：
Ding Y
中科院分区：
文献类型：
--
作者：
Chen M;Cheng J;Wu Q;Zhang J;Chen Y;Zeng H;Ye Q;Wu S;Cai S;Wang J;Ding Y
单核细胞增生李斯特菌是一种胞内食源性病原体，能够引起脑膜炎、脑膜脑炎和流产等脑膜炎。近年来，多个国家均有食用菌产品中出现单核细胞增生李斯特菌的报道。目前还没有L.中国蘑菇产品中的单核细胞增多症。因此，本研究的目的是调查的流行和污染水平的L。本研究旨在检测中国市场上食用菌中单核细胞增多症菌株的耐药性，并确定这些菌株的抗生素耐药性和序列类型，为风险评估提供数据。在665份食用菌样品中检出L. 57.44%（81/141）的阳性样品污染水平小于10 MPN/g。180株分离自阳性样本的菌株属于血清群I.1（1/2a-3a，n = 111），其次是血清群II.2（1/2b-3b-7，n = 66）和血清群III（4a-4c，n = 3）。药敏试验表明，95%以上的L。单核细胞增多症对青霉素、氨苄西林、苯唑西林和克林霉素耐药，而90%以上的单核细胞增多症对16种抗生素敏感，其耐药机制尚待阐明。根据多位点测序分型结果，180株分离株代表21株ST，其中1株为首次鉴定。有趣的是，ST 8和ST 87在食用菌产品中占主导地位，这表明特定的ST可能具有不同的生态位。潜在的毒力谱显示，大多数分离物含有全长inlA基因，在分离物2035- 1 LM（1380位，TGG→TGA）和3419- 1 LM（1474位，CAG→TAG）中发现了新的提前终止密码子。属于血清群II.2的5株分离株携带李斯特菌致病岛（LIPI）-3的llsX基因，存在于ST 224、ST 3和ST 619中; 53株（29.44%）携带来自LIPI-4的ptsA基因，存在于ST 3、ST 5、ST 87、ST 310、ST 1166和ST 619中。结果表明，食用菌可能是潜在的高毒力L.单核细胞增多症，这可能是消费者非常关注的公共卫生问题。根据我们的研究结果，探索新的方法来控制L。单核细胞增多症的污染是必要的，以确保食用菌产品的微生物安全性。
Listeria monocytogenes, an intracellular foodborne pathogen, is capable of causing listeriosis, such as meningitis, meningoencephalitis, and abortion. In recent years, the occurrence of Listeria monocytogenes in edible mushroom products has been reported in several countries. There are no guidelines for qualitative and quantitative detection of L. monocytogenes in mushroom products in China. Therefore, this study aimed to investigate the prevalence and contamination level of L. monocytogenes in edible mushrooms in Chinese markets and to determine the antibiotic resistance and sequence types (STs) of these isolates to provide data for risk assessments. Approximately 21.20% (141/665) of edible mushroom samples were positive for L. monocytogenes, while 57.44% (81/141) of positive samples contained contamination levels of less than 10 MPN/g. The 180 isolates derived from positive samples belonged to serogroup I.1 (1/2a-3a, n = 111), followed by serogroup II.2 (1/2b-3b-7, n = 66), and serogroup III (4a-4c, n = 3). Antibiotic susceptibility testing showed that over 95% of L. monocytogenes isolates were resistant to penicillin, ampicillin, oxacillin, and clindamycin, while over 90% were susceptible to 16 antibiotic agents, the mechanisms of resistance remain to be elucidated. According to multilocus sequencing typing, the 180 isolates represented 21 STs, one of which was identified for the first time. Interestingly, ST8 and ST87 were predominant in edible mushroom products, indicating that specific STs may have distinct ecological niches. Potential virulence profiles showed that most of the isolates contained full-length inlA genes, with novel premature stop codons found in isolate 2035-1LM (position 1380, TGG→TGA) and 3419-1LM (position 1474, CAG→TAG). Five isolates belonging to serogroup II.2 carried the llsX gene from Listeria pathogenicity island (LIPI)-3, present in ST224, ST3, and ST619; 53 (29.44%) harbored the ptsA gene from LIPI-4, presenting in ST3, ST5, ST87, ST310, ST1166, and ST619. Five potential hypervirulent isolates carrying all three of these virulence factors were identified, suggesting edible mushrooms may serve as possible transmission routes of potential hypervirulent L. monocytogenes, which may be of great public health concern to consumers. Based on our findings, the exploration of novel approaches to control L. monocytogenes contamination is necessary to ensure the microbiological safety of edible mushroom products.