Experimental Toxigenicity of NAG Vibrios

Some strains of NAG vibrios isolated from the stool of patients with diarrhoeal disease as well as from surface water caused an accumulation of fluid in the ligated rabbit gut loop. 5-fold concentrated sterile culture filtrates of some strains were found positive in this test as well. The volume of the accumulated fluid in gut loops injected with live cultures as well as with concentrated culture filtrates was apparently smaller than the volume accumulated after injection of non-concentrated V.cholerae culture filtrates. This points to the fact that the NAG vibrio strains belong to weaker producers of enterotoxin than the cholera vibrios. The culture filtrates of all investigated strains contained the skin toxin which was of increased vascular permeability in the skin of rabbits. Besides this, a hemorrhagic effect was found in the filtrates. The skin toxin of NAG vibrios appears to be more heat resistant than the toxin of cholera vibrios. The presence of the skin toxin in culture filtrates, however, does not correlate with the enteropathogenicity of NAG vibrio strains.