EVALUATION OF GAS-LIQUID-CHROMATOGRAPHY (GLC) FOR RAPID DETECTION OF CLOSTRIDIUM-DIFFICILE IN FECAL SPECIMENS

Clostridium difficile intestinal infection is a major nosocomial hazar d in patients receiving antimicrobial therapy. Rationale for rapid dia gnosis include lifesaving antimicrobial therapy in patients with sever e colitis and early isolation measures for transmission control. We ha ve therefore analysed the sensitivity, specificity and predictive valu e of GLC identification of isocaproic acid in diarrheic stools from ad ult hospitalized patients in comparison with selective fecal culture o n Cycloserine Cefoxitin Fructose Agar. During the study period, the pr evalence of positive culture for C. difficile was 38/595 fecal specime ns (6.4%). Compared with culture, GLC had a sensitivity of 24/38 (63%) and a specificity of 524/557 (94%). The predictive value of a positiv e GLC was 24/57 (42%) and of a negative GLC was 524/538 (97%). Measure ment of the isocaproic acid peak height did not allow determination of a curt-off value improving the test accuracy. The sensitivity of dete ction of isocaproic acid in stools by GLC is too low to be used as scr eening test for C. difficile infection. However, in a low prevalence p opulation, a positive GLC test increased the pre-test probability of i nfection sevenfold.