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Abstract：
Listeria monocytogenes is a ubiquitous bacterial pathogen that threatens the food chain and human health. In this study, whole-genome sequencing (WGS) was used for the genomic characterization of L. monocytogenes (n = 24) from beef and beef-based products. Multilocus Sequence Type (MLST) analysis revealed that ST204 of CC204 was the most common sequence type (ST). Other sequence types detected included ST1 and ST876 of CC1, ST5 of CC5, ST9 of CC9, ST88 of CC88, ST2 and ST1430 of CC2, and ST321 of CC321. Genes encoding for virulence factors included complete LIPI-1 (pfrA-hly-plcA-plcB-mpl-actA) from 54% (13/24) of the isolates of ST204, ST321, ST1430, and ST9 and internalin genes inlABC that were present in all the STs. All the L. monocytogenes STs carried four intrinsic/natural resistance genes, fosX, lin, norB, and mprF, conferring resistance to fosfomycin, lincosamide, quinolones, and cationic peptides, respectively. Plasmids pLGUG1 and J1776 were the most detected (54% each), followed by pLI100 (13%) and pLM5578 (7%). The prophage profile, vB_LmoS_188, was overrepresented amongst the isolates, followed by LP_101, LmoS_293_028989, LP_030_2_021539, A006, and LP_HM00113468. Listeria genomic island 2 (LGI-2) was found to be present in all the isolates, while Listeria genomic island 3 (LGI-3) was present in a subset of isolates (25%). The type VII secretion system was found in 42% of the isolates, and sortase A was present in all L. monocytogenes genomes. Mobile genetic elements and genomic islands did not harbor any virulence, resistance, or environmental adaptation genes that may benefit L. monocytogenes. All the STs did not carry genes that confer resistance to first-line antibiotics used for the treatment of listeriosis. The characterization of L. monocytogenes in our study highlighted the environmental resistance and virulence potential of L. monocytogenes and the risk posed to the public, as this bacterium is frequently found in food and food processing environments.
摘要：
单核细胞增生李斯特菌是一种普遍存在的细菌病原体，威胁着食物链和人类健康。在这项研究中,使用全基因组测序(WGS)对来自牛肉和牛肉产品的单核细胞增生李斯特菌(n=24)进行基因组鉴定.多位点序列类型(MLST)分析显示CC204的ST204是最常见的序列类型(ST)。检测到的其它序列类型包括CC1的ST1和ST876、CC5的ST5、CC9的ST9、CC88的ST88、CC2的ST2和ST1430以及CC321的ST321。编码毒力因子的基因包括来自54％（13/24）的ST204，ST321，ST1430和ST9的分离株中的完整LIPI-1（pfrA-hly-plcA-plcB-mpl-actA）以及存在于所有STs中的inlABC基因。所有的单核细胞增生李斯特菌都携带四个内在/天然抗性基因，FosX,林，norB,和mprF,赋予对磷霉素的抗性，lincosamide,喹诺酮类药物,和阳离子肽，分别。质粒pLGUG1和J1776检测最多(各54%)，其次是pLI100（13%）和pLM5578（7%）。预言简介，vB_LmoS_188在分离株中的比例过高，其次是LP_101、LmoS_293_028989、LP_030_2_021539、A006和LP_HM00113468。发现李斯特菌基因组岛2（LGI-2）存在于所有分离物中，而李斯特菌基因组岛3（LGI-3）存在于分离株的子集中（25％）。在42%的分离株中发现了VII型分泌系统，分选酶A存在于所有单核细胞增生李斯特菌基因组中。可移动的遗传元件和基因组岛没有任何毒力，阻力,或可能有益于单核细胞增生李斯特菌的环境适应基因。所有ST均未携带对用于治疗李斯特菌病的一线抗生素具有抗性的基因。在我们的研究中，单核细胞增生李斯特菌的特征强调了单核细胞增生李斯特菌的环境抗性和毒力潜力以及对公众构成的风险，因为这种细菌经常在食品和食品加工环境中发现。
