沿岸海水における腸炎ビブリオの季節的消長と細菌フローラ
1976 年 42 巻 9 号 p. 1041-1053
詳細
1976 年 42 巻 9 号 p. 1041-1053
During 1974 and 1975, the relationship between the seasonal occurence of Vibrio parahaemolyticus in coastal sea-water and its surrounding bacterial flora was investigated. High counts of V. parahaemolyticus in water samples, ranging from 10 to 104 per 100ml, were obtained in the summer months, while in winter, the organisms disappeared. The seasonal variation in bacterial plate counts of sea-waters determined by 7 day incubation at 25°C was quite random. Among the strains isolated at 25°C only two genera, Vibrio and Pseudomonas, dominated independent of seasonal variations in water temperature. However, the growth temperature ranges of these organisms correlated with the seasons in which they were isolated, most of the summer isolates being able to grow at 35°C, while winter isolates were not.
The plate count values obtained at difterent incubation temperatures, namely, 25, 37, 40, 42 and 44°C were compared with seasonal variations. A close correlation between the level of incidence of V. paraheamolyticus and the plate counts obtained with 42Cª incubation was found. Among the bacterial flora on the plate count media incubated at 42°C Vibrio and Pseudomonas constituted a relatively large percentage of the summer population, while gram positive rod bacteria predominated from October to December. Most of the Vibrtio strains isolated at 42°C were identified as V. alginolyticus. It was revealed that V. parahaemolyticus in coastal sea-water is accompanied by greater numbers of V. alginolyticus during the summer season.
