Studies of stools from pseudomembranous colitis, rotaviral, and other diarrheal syndromes by frequency-pulsed electron capture gas-liquid chromatography.

Thirty-five patients with various diarrheal syndromes and 22 controls were studied. All stool samples were carefully cultured for Clostridium difficile, using selective isolation media. Cytotoxin assays with proper antitoxin neutralization were done in MRC-5 cells. The stool samples were extracted four times, three times at pH 2 and once at pH 10, using CHCl3 or ether. Derivatizations of extracts were done with trichloroethanol, heptafluorobutyric anhydride, and heptafluorobutyric anhydride-ethanol, and all derivatives were analyzed by frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC). A dedicated computer was used to assist in both qualitative and quantitative data analysis. Isocaproic acid (iC6) was always found in stool from which C. difficile was isolated and was absent in C. difficile-negative specimens. p-Cresol was found frequently in both persons with pseudomembranous colitis and controls. Tryptamine was found in stool containing C. bifermentans. The FPEC-GLC profiles of persons with acute diarrhea were very different from those of normal persons. Diarrhea associated with adenovirus and rotavirus, Klebsiella spp., and Escherichia spp. showed different FPEC-GLC patterns. Stools from well persons consistently contained full-scale peaks of pyruvic, acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids. In rotavirus stools isobutyric, isovaleric, and valeric acids were reduced in quantity from those found in control stools, whereas propionic and butyric acids were increased.