DETECTION OF HEMOLYTIC-ACTIVITY OF CAMPYLOBACTERS BY AGAROSE HEMOLYSIS AND MICROPLATE ASSAY

There are several methods for the detection of haemolytic activity in campylobacters. However, we found the haemolytic effect of campylobact ers on conventional blood agar plates to be variable, inconsistent and difficult to interpret. Blood agarose plates showed campylobacter hae molytic activity more clearly. The incubation conditions (temperature and gaseous) appear to be important for the expression of this activit y. Ninety four percent of the Campylobacter isolates examined were fou nd to be haemolytic by the microplate assay with minimal haemolytic un its that ranged from 1 to 64. Haemolytic activity was detected only fr om live bacterial cultures and not from any of the 50 bacterial cultur e supernates, which suggests that campylobacters may possess a cell-as sociated haemolysin. The identification of such haemolytic activity in a large number of campylobacters (94%) suggests its potential role as a virulence factor in campylobacter gastroenteritis.