Department of Molecular Biology, Umeå University, S-901 87 Umeå, Sweden.
Environ Microbiol Rep. 2010 Feb;2(1):133-9. doi: 10.1111/j.1758-2229.2009.00120.x. Epub 2010 Jan 4.
Vibrio anguillarum causes a fatal haemorrhagic septicaemia in marine fish. During initial stages of infection, host surfaces are colonized; however, few virulence factors required for colonization of the host are identified. In this study, in vivo bioluminescent imaging was used to analyse directly the colonization of the whole rainbow trout animal by V. anguillarum. The wild type rapidly colonized both the skin and the intestines by 24 h; however, the bacterial numbers on the skin were significantly higher than in the intestines indicating that skin colonization may be important for disease to occur. Mutants defective for the anguibactin iron uptake system, exopolysaccharide transport, or Hfq, an RNA chaperone, were attenuated for virulence, did not colonize the skin, and penetrated skin mucus less efficiently than the wild type. These mutants, however, did colonize the intestines and were as resistant to 2% bile salts as is the wild type. Moreover, exopolysaccharide mutants were significantly more sensitive to lysozyme and antimicrobial peptides, while the Hfq and anguibactin mutants were sensitive to lysozyme compared with the wild type. Vibrio anguillarum encodes several mechanisms to protect against antimicrobial components of skin mucus enabling an amazingly abundant growth on the skin enhancing its disease opportunities.
鳗弧菌可引起海洋鱼类的致命性出血性败血症。在感染的初始阶段，宿主表面会被定植；然而，目前仅鉴定出了少量定植宿主所需的毒力因子。在本研究中，我们采用活体生物发光成像技术直接分析了鳗弧菌对整条彩虹鳟鱼的定植情况。野生型菌在 24 小时内迅速定植于鱼的皮肤和肠道；然而，皮肤表面的细菌数量明显高于肠道，这表明皮肤定植可能对疾病的发生很重要。铁摄取系统、胞外多糖转运或 RNA 伴侣 Hfq 缺陷的突变体毒力减弱，不能定植于皮肤，且穿透皮肤黏液的效率也低于野生型菌。然而，这些突变体可以定植于肠道，且对 2%胆汁盐的耐药性与野生型菌相当。此外，与野生型菌相比，胞外多糖突变体对溶菌酶和抗菌肽更为敏感，而 Hfq 和 anguibactin 突变体对溶菌酶敏感。鳗弧菌编码了几种机制来抵御皮肤黏液中的抗菌成分，使其能够在皮肤表面大量生长，从而增强其发病机会。
