Diarrea asociada a Clostridium difficile: Evaluación de varios métodos de diagnóstico

Abstract

Clostridium difficile is the principal pathogen related to antibiotic associated diarrhea and/or pseudomembranous colitis in hospitalized patients. The diagnosis is based on the clinical suspicion and the presense of a positive laboratory test for the detection of toxin of C. difficile, but the confirmation is based on the cytotoxicity test. Recently vartious immunoassays have been introduced that allow a rapid diagnosis of this disease, but they have different sensibility and specificity and that is why the need to be evaluated with respect to the reference method. The objective of this study was to evaluate correlation between 5 immunoassays and this confirmatory cytotoxicicty method. The stool samples of 60 patients with clinical suspicion of C. difficile associated diarrhea were studied by 4 immunoasssays: 3 ELISA (Tox A Meridian TM, Tox A Becton Dickinson TM and ToxA+B Tech Lab TM) and one immunochromatographic card type: Immunocard Tox A Meridian TM. Forty-six out of sixty samples were tested by a recently introduced card: C. difficile Tox A Oxoid TM. The cytotoxicity assay was considered the confirmatory test. The sensitivity and specificity observed for Tox A Meridian TM was 95.7% and 78,8% respectively, for Tox A Becton Dickinson TM it was 100% and 94.4% for Tox A+B Tech Lab TM it was 91.3% and 86.5%, for Immunocard Tox A Meridian TM it was 87% and 94.6% and for C. difficile Tox A Oxoid TM it was 94.7% and 96.3%. According to the results we found, the most recommended tests are Tox A Becton Dickinson TM and C. difficile Tox A Oxoid TM. Which of these to choose depends on the equipment of the laboratory and necessity of a rapid result.