Ellison R K, Malnati E, Depaola A, Bowers J, Rodrick G E
Department of Food Science and Human Nutrition, University of Florida, Gainesville 32611, USA.
J Food Prot. 2001 May;64(5):682-6. doi: 10.4315/0362-028x-64.5.682.
Vibrio parahaemolyticus is a naturally occurring estuarine bacterium that is often associated with gastroenteritis in humans following consumption of raw molluscan shellfish. A number of studies have investigated the environmental distribution of V. parahaemolyticus, but little is known about the levels of this organism during distribution of oysters or at the point of consumption. Duplicate samples of shellstock oysters were collected monthly (September 1997 to May 1998) from the same four restaurants and three wholesale seafood markets in the Gainesville, Fla. area and analyzed for total V. parahaemolyticus densities using two methods: a standard MPN method (BAM-MPN) and a new direct plating procedure (direct-VPAP). Both methods employed an alkaline phosphatase-labeled DNA probe (VPAP) targeting the species-specific thermolabile hemolysin (tlh) gene to confirm suspect colonies as V. parahaemolyticus. The highest monthly geometric mean V. parahaemolyticus density was observed in October of 1997 (approximately 3,000/g) with similarly high values during September and November of 1997. From December 1997 to May 1998 mean densities were generally less than 100/g, falling to approximately 10/g in February and March. A strong correlation (r = 0.78) between the direct-VPAP and BAM-MPN methods for determining V. parahaemolyticus densities in market-level oysters was observed. The direct-VPAP method was more rapid and precise while the BAM-MPN was more sensitive and may better recover stressed cells. The utilization of the VPAP probe for identification of V. parahaemolyticus sharply reduced the labor for either method compared to biochemical identification techniques used in earlier V. parahaemolyticus surveys.
副溶血性弧菌是一种天然存在的河口细菌，人类食用生的软体贝类后常引发肠胃炎。许多研究调查了副溶血性弧菌的环境分布，但对于该菌在牡蛎销售过程中或消费点的含量却知之甚少。1997年9月至1998年5月，每月从佛罗里达州盖恩斯维尔地区的四家相同餐馆和三个海鲜批发市场采集牡蛎样本，并采用两种方法分析副溶血性弧菌的总密度：标准MPN法（BAM-MPN）和新的直接平板接种法（direct-VPAP）。两种方法均使用碱性磷酸酶标记的DNA探针（VPAP）靶向物种特异性不耐热溶血素（tlh）基因，以确认可疑菌落为副溶血性弧菌。1997年10月观察到副溶血性弧菌的最高月几何平均密度（约3000/g），1997年9月和11月也有类似的高值。1997年12月至1998年5月，平均密度一般低于100/g，2月和3月降至约10/g。观察到direct-VPAP法和BAM-MPN法在测定市场级牡蛎中副溶血性弧菌密度方面具有很强的相关性（r = 0.78）。direct-VPAP法更快速、精确，而BAM-MPN法更灵敏，可能能更好地回收受胁迫的细胞。与早期副溶血性弧菌调查中使用的生化鉴定技术相比，利用VPAP探针鉴定副溶血性弧菌大幅减少了两种方法的工作量。
