The Effect Of Cell-Free Fluids Prepared From Cultures Of Human And Animal Enteropathogenic Strains Of Escherichia Coli On Ligated Intestinal Segments Of Rabbits And Pigs

The relatively labile (LT) form of the enterotoxin produced by pig-entero-pathogenic strains of Escherichia coli strongly dilated ligated segments of rabbit intestine; the more stable (ST) form had a weaker effect. Dilatation was also produced by LT-type preparations of some non-enteropathogenic pig strains.

Similar preparations of cultures of bovine and ovine enteropathogenic strains failed to dilate rabbit and pig intestine; those of the human strains tested also failed to dilate pig intestine.

LT-type preparations of many of the human enteropathogenic strains dilated rabbit intestine; so did a smaller proportion of the non-enteropathogenic human strains tested. The dilating ability of these preparations was destroyed, or markedly reduced, by exposure to heat at 65°C for 15 min. The activity was also neutralised by antiserum in a serotype-specific or strainspecific manner.