Development of a Sensitive Serological Assay Based on Reversed Passive Hemagglutination for Detection of Enteropathogenic Toxin (Kanagawa Hemolysin) of Vibrio parahaemolyticus, and Re-evaluation of the Toxin Producibility of Isolates from Various Sources

Abstract

Based on reversed passive hemagglutination, a sensitive and specific serological assay was developed for detection of enteropathogenic toxin produced by Vibrio parahaemolyticus. It was so sensitive as to make the detection of 1ng/ml of the toxin practicable.
By using the assay, vibrios isolated from various sources were examined for toxin-produ-cibility. Kanagawa phenomenon-positive isolates of human origin produced more than 1μg/ml of the toxin. Most of the Kanagawa-negative and Kanagawa-questionable isolates from fecal specimens of gastroenteritis patients produced a smaller amount of the toxin. Those obtained from seafish, shellfish or their cooking utensils did not produce any detectable amount of the toxin. Based on these findings, the role of the toxin was discussed in causing diarrhea in the case of gastroenteritis due to Kanagawa-negative Vibrio parahaemolyticus.