Ushijima Blake, Videau Patrick, Burger Andrew H, Shore-Maggio Amanda, Runyon Christina M, Sudek Mareike, Aeby Greta S, Callahan Sean M
Department of Microbiology, University of Hawai'i, Honolulu, Hawai'i, USA.
Appl Environ Microbiol. 2014 Apr;80(7):2102-9. doi: 10.1128/AEM.03463-13. Epub 2014 Jan 24.
Identification of a pathogen is a critical first step in the epidemiology and subsequent management of a disease. A limited number of pathogens have been identified for diseases contributing to the global decline of coral populations. Here we describe Vibrio coralliilyticus strain OCN008, which induces acute Montipora white syndrome (aMWS), a tissue loss disease responsible for substantial mortality of the coral Montipora capitata in Kāne'ohe Bay, Hawai'i. OCN008 was grown in pure culture, recreated signs of disease in experimentally infected corals, and could be recovered after infection. In addition, strains similar to OCN008 were isolated from diseased coral from the field but not from healthy M. capitata. OCN008 repeatedly induced the loss of healthy M. capitata tissue from fragments under laboratory conditions with a minimum infectious dose of between 10(7) and 10(8) CFU/ml of water. In contrast, Porites compressa was not infected by OCN008, indicating the host specificity of the pathogen. A decrease in water temperature from 27 to 23°C affected the time to disease onset, but the risk of infection was not significantly reduced. Temperature-dependent bleaching, which has been observed with the V. coralliilyticus type strain BAA-450, was not observed during infection with OCN008. A comparison of the OCN008 genome to the genomes of pathogenic V. coralliilyticus strains BAA-450 and P1 revealed similar virulence-associated genes and quorum-sensing systems. Despite this genetic similarity, infections of M. capitata by OCN008 do not follow the paradigm for V. coralliilyticus infections established by the type strain.
鉴定病原体是疾病流行病学及后续管理的关键第一步。对于导致全球珊瑚种群数量下降的疾病，已鉴定出的病原体数量有限。在此，我们描述了溶珊瑚弧菌菌株OCN008，它会引发急性多孔鹿角珊瑚白综合征（aMWS），这是一种组织损失疾病，导致夏威夷卡内奥赫湾的头状多孔鹿角珊瑚大量死亡。OCN008在纯培养物中生长，在实验感染的珊瑚中重现了疾病症状，并且在感染后可以被分离出来。此外，从患病珊瑚中分离出了与OCN008相似的菌株，但从健康的头状多孔鹿角珊瑚中未分离出。在实验室条件下，OCN008能反复导致头状多孔鹿角珊瑚碎片上的健康组织损失，最低感染剂量为每毫升水10(7)至10(8) 个菌落形成单位（CFU）。相比之下，扁缩滨珊瑚未被OCN008感染，这表明该病原体具有宿主特异性。水温从27°C降至23°C会影响疾病发作时间，但感染风险并未显著降低。在OCN008感染期间未观察到溶珊瑚弧菌模式菌株BAA - 450所出现的温度依赖性白化现象。将OCN008的基因组与致病性溶珊瑚弧菌菌株BAA - 450和P1的基因组进行比较，发现了相似的毒力相关基因和群体感应系统。尽管存在这种基因相似性，但OCN008对头状多孔鹿角珊瑚的感染并不遵循模式菌株所确立的溶珊瑚弧菌感染模式。
