BACKGROUND Listeria monocytogenes is the causative agent of listeriosis, a serious disease affecting both animals and humans. Here, multilocus sequence typing (MLST) was used to characterize the genetic diversity of Listeria monocytogenes strains isolated from the natural environment and animal clinical cases in Europe. The prevalence of clonal complexes (CCs) obtained was compared according to (i) the origin of isolation - clinical cases vs. natural environment - and (ii) the clinical form of animal listeriosis - rhombencephalitis vs. abortion. To this aim, two datasets were constructed. The clinical dataset consisted of 350 animal clinical isolates originating from France and Slovenia and supplemented with isolates from Switzerland and Great Britain. The natural environment dataset consisted of 253 isolates from the natural environment originating from Slovenia and supplemented with isolates from nine other European countries. RESULTS For the clinical cases, CC1, CC4-CC217 and CC412 were the most prevalent in rhombencephalitis and CC1, CC37 and CC4-CC217 in abortion. The hypervirulent CC1 and CC4-CC217 prevailed in both datasets. These results indicated that livestock is constantly exposed to hypervirulent CCs. CC1 was significantly associated with a clinical origin, whereas CC9, CC29 and CC14 were associated with the natural environment. CC1 was predominant among rhombencephalitis cases both in cattle and small ruminants, and its prevalence did not differ significantly between these two groups. A novel association of CC37 and CC6 with abortion cases was revealed. CONCLUSIONS Here, we show that CC1 and CC4-CC217 are prevalent in isolates of environmental and animal clinical origin, suggesting that ruminants are frequently exposed to hypervirulent CCs. The presence of CC4 in two mastitis cases calls for further attention due to direct threat to the consumer. We showed several associations between CCs and the origin of isolation or clinical form of listeriosis, e.g. CC37 and CC6 with abortion. This study improves our understanding of the population structure of L. monocytogenes isolates from the natural environment and animal clinical cases. Moreover, it provides a basis for future studies aiming to determine the underlying mechanisms of phenotypic traits of interest.

中文翻译：

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反刍动物流产和菱形脑炎李斯特菌菌株的遗传多样性与自然环境的比较。

背景技术单核细胞增生性李斯特菌是李斯特氏菌病的病原体，李斯特菌病是一种严重的疾病，同时影响动物和人类。在这里，多基因座序列分型（MLST）用于表征从自然环境和欧洲动物临床案例中分离出的单核细胞增生李斯特菌菌株的遗传多样性。根据（i）分离的起源-临床病例与自然环境-和（ii）动物李斯特菌病的临床形式-菱形脑炎与流产比较了获得的克隆复合物（CCs）的患病率。为此，构建了两个数据集。临床数据集包含来自法国和斯洛文尼亚的350种动物临床分离株，并补充了来自瑞士和英国的分离株。自然环境数据集由253种来自斯洛文尼亚的自然环境分离株组成，并补充了来自其他9个欧洲国家的分离株。结果对于临床病例，CC1，CC4-CC217和CC412在菱形脑炎中最普遍，而CC1，CC37和CC4-CC217在流产中最为普遍。高毒CC1和CC4-CC217在这两个数据集中均占主导地位。这些结果表明，牲畜不断暴露于高毒CC。CC1与临床起源显着相关，而CC9，CC29和CC14与自然环境相关。CC1在牛和小反刍动物的菱形脑炎病例中占主导地位，这两组的患病率无显着差异。揭示了CC37和CC6与流产病例的新型关联。结论在这里，我们显示CC1和CC4-CC217在环境和动物临床起源的分离株中普遍存在，这表明反刍动物经常暴露于高毒性CC中。由于对消费者的直接威胁，在两个乳腺炎病例中CC4的存在需要进一步关注。我们显示了CC与李斯特菌病分离或临床形式的起源之间的多种关联，例如流产的CC37和CC6。这项研究提高了我们对自然环境和动物临床病例中单核细胞增生李斯特氏菌的种群结构的了解。而且，它为将来的研究提供了基础，这些研究旨在确定感兴趣的表型性状的潜在机制。这表明反刍动物经常接触高毒CC。由于对消费者的直接威胁，在两个乳腺炎病例中CC4的存在需要进一步关注。我们显示了CC与李斯特菌病分离或临床形式的起源之间的多种关联，例如流产的CC37和CC6。这项研究提高了我们对自然环境和动物临床病例中单核细胞增生李斯特氏菌的种群结构的了解。而且，它为将来的研究提供了基础，这些研究旨在确定感兴趣的表型性状的潜在机制。这表明反刍动物经常接触高毒CC。由于对消费者的直接威胁，在两个乳腺炎病例中CC4的存在需要进一步关注。我们显示了CC与李斯特菌病分离或临床形式的起源之间的多种关联，例如流产的CC37和CC6。这项研究提高了我们对自然环境和动物临床病例中单核细胞增生李斯特氏菌的种群结构的了解。而且，它为将来的研究提供了基础，这些研究旨在确定感兴趣的表型性状的潜在机制。这项研究提高了我们对自然环境和动物临床病例中单核细胞增生李斯特氏菌的种群结构的了解。而且，它为将来的研究提供了基础，这些研究旨在确定感兴趣的表型性状的潜在机制。这项研究提高了我们对自然环境和动物临床病例中单核细胞增生李斯特氏菌的种群结构的了解。而且，它为将来的研究提供了基础，这些研究旨在确定感兴趣的表型性状的潜在机制。