Comparative assessment of virulence traits in Legionella spp.
Comparative assessment of virulence traits in Legionella spp.
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DOI：
10.1099/mic.0.25980-0
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发表时间：
2003-03-01
期刊：
影响因子：
2.8
通讯作者：
Abu-Kwaik, Y
中科院分区：
文献类型：
--
作者：
Alli, OAT;Zink, S;Abu-Kwaik, Y
嗜肺军团菌是一种兼性细胞内病原体，在美国和欧洲占大多数军团病病例，但其他军团菌属。已被证明会导致疾病。相比之下，长滩军团菌是澳大利亚退伍军人病的主要原因。由嗜肺军团菌引起的军团病的特点是肺泡腔吞噬细胞内的细胞内复制，而Dot/lcm IV型分泌系统对于细胞内复制至关重要。尽管据推测吞噬细胞内的细胞内复制是其他有毒力军团菌的标志，但军团菌的毒力特征。除嗜肺军团菌外，尚无明确定义。在这项研究中，27 种军团菌菌株。研究人员对属于从人类或环境中分离出来的 16 个物种的嗜肺军团菌表现出的五种毒力特征进行了检查：细胞致病性、巨噬细胞内的细胞内复制、诱导细胞凋亡/DNA 片段化、孔形成介导的宿主细胞细胞溶解以及 dot/icm 位点的存在。根据使用 U937 人源性巨噬细胞进行的细胞致病性测定，将菌株分为两大类（低细胞致病性组和高细胞致病性组）。在军团菌的低致细胞病变组和高致细胞病变组中评估了其他四种毒力性状。大多数嗜肺军团菌血清组 1 菌株在 72 小时后具有高度细胞致病性，表现出高水平的细胞内生长，诱导细胞凋亡/DNA 断裂，并表现出成孔活性。大多数其他物种是低致细胞病变组，不诱导细胞凋亡，也不表现出成孔活性。通过 DNA 杂交检查时，所有测试的军团菌物种均具有所有 dot/icm 基因座。未发现细胞致病性与其他四种致病性状之间存在相关性。
Legionella pneumophila is a facultative intracellular pathogen that accounts for the majority of cases of Legionnaires' disease in the USA and Europe, but other Legionella spp. have been shown to cause disease. In contrast, Legionella longbeachae is the leading cause of Legionnaires' disease in Australia. The hallmark of Legionnaires' disease caused by L. pneumophila is the intracellular replication within phagocytes in the alveolar spaces, and the Dot/lcm type IV secretion system is essential for intracellular replication. Although it has been presumed that intracellular replication within phagocytes is the hallmark of other virulent legionellae, the virulence traits of Legionella spp. apart from L. pneumophila are not well defined. In this study, 27 strains of Legionella spp. belonging to 16 species that have been isolated from humans or from the environment were examined for five virulence traits exhibited by L. pneumophila: cytopathogenicity, intracellular replication within macrophages, induction of apoptosis/DNA fragmentation, pore-formation-mediated cytolysis of the host cell, and the presence of the dot/icm loci. The strains were divided into two broad groups (low and high cytopathogenic groups) based on cytopathogenicity assays using U937 human-derived macrophages. The other four virulence traits were evaluated in the low and high cytopathogenic groups of Legionella species. Most L. pneumophila serogroup 1 strains were highly cytopathogenic after 72 h, manifested high levels of intracellular growth, induced apoptosis/DNA fragmentation, and exhibited pore-forming activity. The majority of the other species were the low cytopathogenic group that did not induce apoptosis, neither did they exhibit pore-forming activity. All the species of legionellae tested have all the dot/icm loci, when examined by DNA hybridization. No correlation was found between cytopathogenicity and the other four pathogenic traits.