RESUMEN
Coliform bacteria were isolated by either aerobic or anaerobic culture techniques from aspirates of the proximal small intestine of 4 of 5 Haitians with tropical sprue, but not from any of 10 well nourished Haitians who had milder gastrointestinal complaints and abnormalities. Klebsiella (Klebsiella pneumoniae and Klebsiella ozaenae) was cultured from the jejunal aspirates of 2 sprue patients and Escherichiae coli from the other 2. Fifteen colonies of coliform bacteria cultured from each aspirate were specifically identified by their biotype. In three instances, every colony in each aspirate was the same; In three instances, every colony in each aspirate was the same; in the fourth aspirate, two biotypes of E. coli were present, one of which grew under both aerobic and anaerobic culture conditions and another which grew only under anaerobic conditions on initial isolation. A randomly selected strain of each of the five coliform biotypes isolated was examined for enterotoxigenicity by determining the effect of variously prepared cell-free preparations on water transport in the rat jejunum using standard marker perfusion techniques. Every strain tested was toxigenic; one produced only a heat-stable toxin, one produced a heat-labile toxin only, and three elaborated both forms of enterotoxin. These observations indicate that most Haitians with tropical sprue have colonization of the proximal small intestine by a specific strain of enterotoxigenic coliform bacteria, but such is not the case among Haitians who have milder intestinal abnormalities.