Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy.
Arch Microbiol. 2013 Feb;195(2):89-96. doi: 10.1007/s00203-012-0851-9. Epub 2012 Nov 8.
Three Legionella pneumophila strains isolated from municipal hot tap water during a multicentric Italian survey and belonging to serogroups 1, 6, 9 and the reference strain Philadelphia-1 were studied to determine the intracellular replication capability and the cytopathogenicity in human monocyte cell line U937 and in an Acanthamoeba polyphaga strain. Our results show that both serogroups 1 and Philadelphia-1 were able to multiply into macrophages inducing cytopathogenicity, while serogroup 6 and ever more serogroup 9 were less efficient in leading to death of the infected macrophages. Both serogroups 1 and 6 displayed a quite good capability of intracellular replication in A. polyphaga, although serogroup 1 was less cytopathogenic than serogroup 6. Serogroup 9, like Philadelphia-1 strain, showed a reduced efficiency of infection and replication and a low cytopathogenicity towards the protozoan. Our study suggests that bacterial pathogenesis is linked to the difference in the virulence expression of L. pneumophila serogroups in both hosts, as demonstrated by the fact that only L. pneumophila serogroup 1 shows the contextual expression of the two virulence traits. Serogroup 6 proves to be a good candidate as pathogen since it shows a good capacity for intracellular replication in protozoan.
对从意大利一个多中心调查中的市政热水龙头中分离出的 3 株嗜肺军团菌菌株（血清群 1、6、9 和参考株 Philadelphia-1）进行了研究，以确定它们在人单核细胞系 U937 和粘质沙雷氏菌中的细胞内复制能力和细胞病变能力。我们的结果表明，血清群 1 和 Philadelphia-1 均能在巨噬细胞中增殖并诱导细胞病变，但血清群 6 和血清群 9 导致感染巨噬细胞死亡的效率较低。血清群 1 和 6 在粘质沙雷氏菌中均具有相当好的细胞内复制能力，尽管血清群 1 的细胞病变能力不如血清群 6。血清群 9 与 Philadelphia-1 株一样，对原生动物的感染和复制效率降低，细胞病变能力较低。我们的研究表明，细菌发病机制与嗜肺军团菌血清群在两种宿主中的毒力表达差异有关，这一事实表明，只有嗜肺军团菌血清群 1 表现出两种毒力特征的语境表达。血清群 6 被证明是一种很好的病原体候选物，因为它在原生动物中具有良好的细胞内复制能力。
