Apparent Loss of Vibrio vulnificus from North Carolina Oysters Coincides with a Drought-Induced Increase in Salinity
Apparent Loss of Vibrio vulnificus from North Carolina Oysters Coincides with a Drought-Induced Increase in Salinity
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DOI：
10.1128/aem.07855-11
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发表时间：
2012-06-01
影响因子：
4.4
通讯作者：
Oliver, James D.
中科院分区：
文献类型：
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作者：
Froelich, Brett A.;Williams, Tiffany C.;Oliver, James D.
尽管从 2007 年开始，多年来从河口水域成功分离出创伤弧菌，但从北卡罗来纳州河口水或牡蛎样本中培养创伤弧菌却极其困难。在采用基于培养的方法以及 PCR 和定量 PCR 检测创伤弧菌后，结果总是阴性，我们得出的结论是，这种病原体在北卡罗来纳州河口生态系统中几乎检测不到。我们通过在北卡罗来纳州牡蛎中接种创伤弧菌并进行与之前在纯牡蛎上进行的相同测试来确保技术的可靠性。使用这两类方法很容易在带籽牡蛎中检测到创伤弧菌。此外，牡蛎是从墨西哥湾获得的，并且很容易分离出创伤弧菌，这证实了该方法是合理的，但北卡罗来纳州的牡蛎和水域缺乏数十年来研究的创伤弧菌种群。引人注目的是，可检测到的创伤弧菌的明显消失恰逢北卡罗来纳州历史上最严重的干旱。干旱一直持续到 2009 年底，在此期间观察到水体盐度升高，而创伤弧菌几乎不存在。 2010年干旱减弱后盐度恢复正常，我们再次能够从水体中常规分离出创伤弧菌，尽管我们仍然无法从牡蛎中培养它。我们认为，在干旱期间，牡蛎被一种更耐盐的细菌定殖，这种细菌取代了创伤弧菌，并可能阻止了重新定殖。
Despite years of successful isolation of Vibrio vulnificus from estuarine waters, beginning in 2007, it was extremely difficult to culture V. vulnificus from either North Carolina estuarine water or oyster samples. After employing culture-based methods as well as PCR and quantitative PCR for the detection of V. vulnificus, always with negative results, we concluded that this pathogen had become nearly undetectable in the North Carolina estuarine ecosystem. We ensured that the techniques were sound by seeding North Carolina oysters with V. vulnificus and performing the same tests as those previously conducted on unadulterated oysters. V. vulnificus was readily detected in the seeded oysters using both classes of methods. Furthermore, oysters were obtained from the Gulf of Mexico, and V. vulnificus was easily isolated, confirming that the methodology was sound but that the oysters and waters of North Carolina were lacking the V. vulnificus population studied for decades. Strikingly, the apparent loss of detectable V. vulnificus coincided with the most severe drought in the history of North Carolina. The drought continued until the end of 2009, with an elevated water column salinity being observed throughout this period and with V. vulnificus being nearly nonexistent. When salinities returned to normal after the drought abated in 2010, we were again able to routinely isolate V. vulnificus from the water column, although we were still unable to culture it from oysters. We suggest that the oysters were colonized with a more salt-tolerant bacterium during the drought, which displaced V. vulnificus and may be preventing recolonization.