Ecological mechanism to restrict the main prevalence area of Vibrio parahaemolyticus to estuaries

在很多个案中，怀疑引致肠胃炎的海产并没有发现副溶血性弧菌。该批怀疑受污染的海产可能除受产TDH菌株污染外，亦受蛭弧菌污染。我在青森的Kanita河口、三重的Miwatari河口和高知的Urado河口的3个河口以及三重的Matsugasaki港口、高知的Murotsu港口和冲绳的Toguchi港口的3个渔港检测到蛭弧菌。使用真细菌的16 S核糖体RNA基因的引物8-27和1492 R，从从Kanita河分离的菌株Ao 1获得PCR产物（约1，500 bp）。PCR扩增产物1059 bp的碱基序列与蛭弧菌16 SrRNA基因同源性为92%，推测Ao 1菌株为蛭弧菌属（Bdellovibrio sp.）。在户口港，2001年9月至2002年9月间歇性检测到蛭弧菌，浓度为10^2至10^4/l，但2002年10月至2003年2月未检测到。当副溶血性弧菌水平低时，蛭弧菌水平高。在松崎港，自2001年11月以来，间歇性地检测到蛭弧菌，水平为10^4/l，但蛭弧菌水平与副溶血性弧菌水平之间的关系尚不清楚。在室津港，从2001年9月至2003年1月，蛭弧菌的水平连续检测到10^3至10^5/l，尽管蛭弧菌水平与副溶血性弧菌水平之间的关系尚不清楚。由于室津港附近没有副溶血性弧菌高浓度生存的河口，蛭弧菌可能在副溶血性弧菌以外的海洋弧菌中生长。

There are many cases that TDH-producing stains of Vibrio parahaemolyticus are not detected from seafood suspected to the cause of gastroenteritis. The suspected seafood might be contaminated with bdellovibrios in addition to TDH-producing strains. I detected bdellovibrios from water at 3 estuaries; Kanita estuary in Aomori, Miwatari estuary in Mie and Urado estuary in Kochi, and 3 fishing ports; Matsugasaki port in Mie, Murotsu port in Kochi and Toguchi port in Okinawa. PCR product (about 1,500 bp) was obtained from strain Ao1 isolated from Kanita river using primers 8-27 and 1492R of 16S ribosomal RNA gene of eubacteria. Base sequence of 1059 bp of the PCR product showed 92% homologous with 16S ribosomal RNA gene of Bdellovibrio sp. So strain Ao1 was suspected to be Bdellovibrio sp.Seasonal variations of bdellovibrios and V. parahaemolyticus have been examined in water at Toguchi, Murotsu and Matsugasaki ports. At Toguchi port, bdellovibrios were detected intermittently at a level of 10^2 to 10^4/l from September 2001 to September 2002 but not detected from October 2002 to February 2003. Levels of bdellovibrios were high when levels of V. parahaemolyticus were low. At Matsugasaki port, bdellovibrios were detected intermittently at a level of 10^4/l since November 2001 though the relationship between the level of bdellovibrios and that of V. parahaemolyticus was not clear. At Murotsu port, bdellovibrios were detected at a level of 10^3 to 10^5/l continuously from September 2001 to January 2003 though the relationship between the level of bdellovibrios and that of V. parahaemolyticus was not clear. As there is no estuary for V. parahaemolyticus can survive at high levels near Murotsu port, bdellovibrios might grow in marine vibrios other than V. parahaemolyticus there.