Genome Analysis of Listeria monocytogenes Sequence Type 8 Strains Persisting in Salmon and Poultry Processing Environments and Comparison with Related Strains.
Genome Analysis of Listeria monocytogenes Sequence Type 8 Strains Persisting in Salmon and Poultry Processing Environments and Comparison with Related Strains.
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DOI：
10.1371/journal.pone.0151117
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Heir E
中科院分区：
文献类型：
--
作者：
Fagerlund A;Langsrud S;Schirmer BC;Møretrø T;Heir E
单核细胞增生李斯特菌是导致李斯特菌病的重要食源性病原体，可在整个环境、许多食品和食品加工设施中发现。李斯特菌病的主要原因是食用了受到食品加工环境污染的食品。在食品加工设施中存在单核增生乳杆菌序列型（ST） 8亚型。在目前的研究中，对5株ST8菌株进行了全基因组测序，并与另外5个可用的ST8基因组进行了比较，从而可以比较来自鲑鱼、家禽和奶酪行业的菌株，以及人类临床分离株。单核苷酸多态性（snp）全基因组分析证实，1996年在丹麦一家鲑鱼加工厂和2001年和2011年在挪威一家鲑鱼加工厂检测到几乎相同的菌株。此外，我们表明单核增生乳杆菌ST8很可能由于加工设备的迁移而在两个家禽加工厂之间转移。SNP数据用于推断ST8菌株的系统发育，将它们分为两个主要遗传群。在各组内，质粒和噬菌体含量几乎完全保守，但在组间，这些序列表现出强烈的差异。ST8菌株的附属基因组包含可能参与使ST8菌株对传入的移动遗传元件具有弹性的遗传元件。其中包括两个限制性修饰位点，其中一个预计通过位点特异性结构域洗牌显示相变量识别序列特异性。分析表明，ST8菌株具有已知所有重要的单核细胞增生乳杆菌毒力因子，ST8菌株通常被认为是侵袭性李斯特菌病的病原体。因此，这种单核增生乳杆菌亚型在食品加工设施中的持续存在引起了对食品安全的重大关注。
Listeria monocytogenes is an important foodborne pathogen responsible for the disease listeriosis, and can be found throughout the environment, in many foods and in food processing facilities. The main cause of listeriosis is consumption of food contaminated from sources in food processing environments. Persistence in food processing facilities has previously been shown for the L. monocytogenes sequence type (ST) 8 subtype. In the current study, five ST8 strains were subjected to whole-genome sequencing and compared with five additionally available ST8 genomes, allowing comparison of strains from salmon, poultry and cheese industry, in addition to a human clinical isolate. Genome-wide analysis of single-nucleotide polymorphisms (SNPs) confirmed that almost identical strains were detected in a Danish salmon processing plant in 1996 and in a Norwegian salmon processing plant in 2001 and 2011. Furthermore, we show that L. monocytogenes ST8 was likely to have been transferred between two poultry processing plants as a result of relocation of processing equipment. The SNP data were used to infer the phylogeny of the ST8 strains, separating them into two main genetic groups. Within each group, the plasmid and prophage content was almost entirely conserved, but between groups, these sequences showed strong divergence. The accessory genome of the ST8 strains harbored genetic elements which could be involved in rendering the ST8 strains resilient to incoming mobile genetic elements. These included two restriction-modification loci, one of which was predicted to show phase variable recognition sequence specificity through site-specific domain shuffling. Analysis indicated that the ST8 strains harbor all important known L. monocytogenes virulence factors, and ST8 strains are commonly identified as the causative agents of invasive listeriosis. Therefore, the persistence of this L. monocytogenes subtype in food processing facilities poses a significant concern for food safety.