Studies have shown that ruminants constitute reservoirs of Listeria monocytogenes, but little is known about the epidemiology and genetic diversity of this pathogen within farms. Here we conducted a large-scale longitudinal study to monitor Listeria spp. in 19 dairy farms during three consecutive seasons (N = 3251 samples). L. innocua was the most prevalent species, followed by L. monocytogenes. Listeria monocytogenes was detected in 52.6% of farms and more frequently in cattle (4.1%) and sheep (4.5%) than in goat farms (0.2%). Lineage I accounted for 69% of L. monocytogenes isolates. Among animal samples, the most prevalent sublineages (SL) and clonal complexes (CC) were SL1/CC1, SL219/CC4, SL26/CC26 and SL87/CC87, whereas SL666/CC666 was most prevalent in environmental samples. Sixty-one different L. monocytogenes cgMLST types were found, 28% common to different animals and/or surfaces within the same farm and 21% previously reported elsewhere in the context of food and human surveillance. Listeria monocytogenes prevalence was not affected by farm hygiene but by season: higher prevalence was observed during winter in cattle, and during winter and spring in sheep farms. Cows in their second lactation had a higher probability of L. monocytogenes faecal shedding. This study highlights dairy farms as a reservoir for hypervirulent L. monocytogenes.

中文翻译：

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与反刍动物相关的单核细胞增生李斯特菌分离物优先属于与乳制品相关的高毒性克隆：在 19 个农场进行的纵向研究

研究表明，反刍动物是单核细胞增生李斯特菌的宿主，但对该病原体在农场内的流行病学和遗传多样性知之甚少。在这里，我们进行了大规模纵向研究以监测李斯特菌属。连续三个季节的 19 个奶牛场（N  = 3251 个样本）。大号_ innocua是最普遍的物种，其次是L。单核细胞增多症。在 52.6% 的农场中检测到单核细胞增生李斯特菌，在牛 (4.1%) 和绵羊 (4.5%) 中检测到的频率高于山羊农场 (0.2%)。Lineage I 占L的 69% 。单核细胞增多症隔离。在动物样本中，最普遍的亚谱系 (SL) 和克隆复合体 (CC) 是 SL1/CC1、SL219/CC4、SL26/CC26 和 SL87/CC87，而 SL666/CC666 在环境样本中最为普遍。六十一个不同的L。发现了单核细胞增多症 cgMLST 类型，28% 在同一农场内的不同动物和/或表面上共有，21% 以前在食品和人类监测的其他地方报道过。单核细胞增生李斯特菌的流行率不受农场卫生的影响，而是受季节影响：在冬季，牛的流行率较高，而在绵羊场的冬季和春季流行率较高。处于第二个泌乳期的奶牛出现L的概率更高。单核细胞增多症粪便脱落。这项研究强调奶牛场是高毒力L的储存库。单核细胞增多症。