title: Use of gas-liquid chromatography as a screening test for toxigenic Clostridium difficile in diarrhoeal stools.
abstract: In order to determine if gas-liquid chromatography (GLC) on concentrated stool extracts could be substituted to cell culture assay for cytotoxicity, we prospectively studied 154 diarrhoeal stools submitted for detection of Clostridium difficile toxin. Isocaproic-positive samples were cultured on egg yolk agar supplemented with cycloserine, cefoxitin and fructose for isolation of C difficile, and on egg yolk agar plus kanamycin for isolation of other clostridium species. Of the 154 samples, 129 were GLC-negative (height of the isocaproic peak less than 1.2 cm) and were toxin-negative. Twenty-five stools yielded isocaproic acid; C difficile isolated from 13 of them, six of which were also toxin-positive. Four other isocaproic-positive samples yielded C bifermentans and C sordellii; all were toxin-negative. These results indicate that a negative GLC is an excellent screening test for excluding C difficile infection; positive results must be checked by toxin testing and culture since they are not necessarily associated with the presence of C difficile or its toxin.
mesh_terms: D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000032:analysis*; D002208:Caproates / Q000032:analysis; D002849:Chromatography, Gas; D003013:Clostridium / Q000302:isolation & purification / Q000378:metabolism; D003015:Clostridium Infections / Q000175:diagnosis*; D003603:Cytotoxins / Q000032:analysis*; D003967:Diarrhea / Q000382:microbiology; D005243:Feces / Q000032:analysis* / Q000382:microbiology; D006801:Humans
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D002208:Caproates; D003603:Cytotoxins; C031815:toxB protein, Clostridium difficile; C034527:isocaproic acid