Cook David W, Bowers John C, DePaola Angelo
Gulf Coast Seafood Laboratory, U.S. Food and Drug Administration, P.O. Box 158, One Iberville Drive, Dauphin Island, Alabama 36528-0158, USA.
J Food Prot. 2002 Dec;65(12):1873-80. doi: 10.4315/0362-028x-65.12.1873.
The densities of total and pathogenic Vibrio parahaemolyticus in 671 samples of molluscan shellfish harvested in 1999 and 2000 from 14 sites in seven Gulf and Atlantic coast states were determined at 2-week intervals over a period of 12 to 16 months in each state. Changes in V. parahaemolyticus densities in shellfish between harvest and sample analysis were minimized with time and temperature controls. Densities were measured by direct plating techniques, and gene probes were used for identification. Total and pathogenic V. parahaemolyticus organisms were identified with probes for the thermolabile direct hemolysin (tlh) gene and the thermostable direct hemolysin (tdh) gene, respectively. An enrichment procedure involving 25 g of shellfish was also used for the recovery of pathogenic V. parahaemolyticus. The densities of V. parahaemolyticus in shellfish from all harvest sites were positively correlated with water temperature. Shellfish from the Gulf Coast typically had higher densities of V. parahaemolyticus than did shellfish harvested from the North Atlantic or mid-Atlantic coast. Vibrio parahaemolyticus counts exceeded 1,000 CFU/g for only 5% of all samples. Pathogenic (tdh+) V. parahaemolyticus was detected in approximately 6% of all samples by both procedures, and 61.5% of populations in the positive samples from the direct plating procedure were at the lower limit of detection (10 CFU/g). The frequency of detection of pathogenic V. parahaemolyticus was significantly related to water temperature and to the density of total V. parahaemolyticus. The failure to detect pathogenic V. parahaemolyticus in shellfish more frequently was attributed to the low numbers and uneven distribution of the organism.
1999年和2000年从墨西哥湾和大西洋沿岸七个州的14个地点采集了671份软体贝类样本，每隔两周测定一次样本中副溶血性弧菌总数及致病性副溶血性弧菌的密度，每个州的测定时间为12至16个月。通过时间和温度控制，尽量减少贝类收获到样本分析期间副溶血性弧菌密度的变化。密度通过直接平板接种技术测定，并用基因探针进行鉴定。分别用针对不耐热直接溶血素（tlh）基因和耐热直接溶血素（tdh）基因的探针鉴定副溶血性弧菌总数及致病性副溶血性弧菌。还采用了一种涉及25克贝类的富集程序来回收致病性副溶血性弧菌。所有收获地点的贝类中副溶血性弧菌密度与水温呈正相关。墨西哥湾沿岸的贝类通常比从北大西洋或中大西洋沿岸收获的贝类含有更高密度的副溶血性弧菌。在所有样本中，只有5%的副溶血性弧菌计数超过1000 CFU/g。通过两种方法在大约6%的所有样本中检测到致病性（tdh+）副溶血性弧菌，直接平板接种程序阳性样本中61.5%的菌量处于检测下限（10 CFU/g）。致病性副溶血性弧菌的检测频率与水温以及副溶血性弧菌总数显著相关。在贝类中未能更频繁地检测到致病性副溶血性弧菌归因于该菌数量少且分布不均。
