Greub Gilbert, Raoult Didier
Unité des Rickettsies, Faculté de Médecine, Université de la Méditerranée, Marseille, France.
Clin Microbiol Rev. 2004 Apr;17(2):413-33. doi: 10.1128/CMR.17.2.413-433.2004.
Free-living amoebae feed on bacteria, fungi, and algae. However, some microorganisms have evolved to become resistant to these protists. These amoeba-resistant microorganisms include established pathogens, such as Cryptococcus neoformans, Legionella spp., Chlamydophila pneumoniae, Mycobacterium avium, Listeria monocytogenes, Pseudomonas aeruginosa, and Francisella tularensis, and emerging pathogens, such as Bosea spp., Simkania negevensis, Parachlamydia acanthamoebae, and Legionella-like amoebal pathogens. Some of these amoeba-resistant bacteria (ARB) are lytic for their amoebal host, while others are considered endosymbionts, since a stable host-parasite ratio is maintained. Free-living amoebae represent an important reservoir of ARB and may, while encysted, protect the internalized bacteria from chlorine and other biocides. Free-living amoebae may act as a Trojan horse, bringing hidden ARB within the human "Troy," and may produce vesicles filled with ARB, increasing their transmission potential. Free-living amoebae may also play a role in the selection of virulence traits and in adaptation to survival in macrophages. Thus, intra-amoebal growth was found to enhance virulence, and similar mechanisms seem to be implicated in the survival of ARB in response to both amoebae and macrophages. Moreover, free-living amoebae represent a useful tool for the culture of some intracellular bacteria and new bacterial species that might be potential emerging pathogens.
自由生活的变形虫以细菌、真菌和藻类为食。然而，一些微生物已经进化出对这些原生生物的抗性。这些抗变形虫的微生物包括已确定的病原体，如新型隐球菌、军团菌属、肺炎衣原体、鸟分枝杆菌、单核细胞增生李斯特菌、铜绿假单胞菌和土拉弗朗西斯菌，以及新出现的病原体，如博斯氏菌属、内格夫希曼菌、棘阿米巴副衣原体和军团菌样阿米巴病原体。其中一些抗变形虫细菌（ARB）对其变形虫宿主具有溶解性，而其他一些则被认为是内共生体，因为它们维持着稳定的宿主-寄生虫比例。自由生活的变形虫是ARB的重要储存库，并且在形成包囊时可能会保护内化的细菌免受氯和其他杀菌剂的影响。自由生活的变形虫可能充当特洛伊木马，将隐藏的ARB带入人类的“特洛伊”，并且可能产生充满ARB的囊泡，增加它们的传播潜力。自由生活的变形虫也可能在毒力性状的选择以及适应在巨噬细胞中生存方面发挥作用。因此，发现变形虫内生长会增强毒力，并且类似的机制似乎与ARB在应对变形虫和巨噬细胞时的存活有关。此外，自由生活的变形虫是培养一些细胞内细菌和可能是潜在新出现病原体的新细菌物种的有用工具。
