title: Laboratory diagnosis of Clostridium difficile-associated diarrhoea: a plea for culture.
abstract: A routine protocol for diagnosing Clostridium difficile-associated diarrhoea (CDAD) based on both faecal-cytotoxin detection and toxigenic culture was adopted by the microbiology laboratory of the St Luc-UCL University Hospital in Brussels in 1997. A toxigenic culture is a faecal culture followed, in the case of positivity, by a direct immunoassay on colonies to detect toxin A production. The results obtained over the past 7 years in the hospital are reviewed here. A total of 10,552 diarrhoeal stools from 7042 patients were analysed, of which 9494 were negative for all tests. A total of 1058 samples (10 %) from 794 patients were culture-positive, of which 460 (4.4 %) were positive for a faecal cytotoxin. The remaining 598 cultures were tested for toxin A on colonies; 355 of them were positive, which is 3.4 % of the total, and the remaining 243 (2.3 %) were negative. The positivity of the faecal-cytotoxin assay was statistically linked to the number of colonies observed on the culture plate. In conclusion, over a 7 year period, toxigenic culture allowed the diagnosis of 355 cases of CDAD that would have been missed by a protocol using a faecal-cytotoxin assay alone. In terms of both patient care, prevention of environmental contamination and prevention of risk of a hospital outbreak, it is proposed that these results justify the recommendation to perform both faecal-toxin assay and culture in routine medical practice.
authors.affiliation: Université Catholique de Louvain, Microbiology Unit, Avenue Hippocrate, 54.90, B-1200 Brussels, Belgium.
authors.forename: Michel
authors.initials: M
authors.lastname: Delmée
authors.affiliation: Université Catholique de Louvain, Microbiology Unit, Avenue Hippocrate, 54.90, B-1200 Brussels, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Van Broeck
authors.affiliation: Université Catholique de Louvain, Microbiology Unit, Avenue Hippocrate, 54.90, B-1200 Brussels, Belgium.
authors.forename: Anne
authors.initials: A
authors.lastname: Simon
authors.affiliation: Université Catholique de Louvain, Microbiology Unit, Avenue Hippocrate, 54.90, B-1200 Brussels, Belgium.
authors.forename: Michèle
authors.initials: M
authors.lastname: Janssens
authors.affiliation: Université Catholique de Louvain, Microbiology Unit, Avenue Hippocrate, 54.90, B-1200 Brussels, Belgium.
authors.forename: Véronique
authors.initials: V
authors.lastname: Avesani
mesh_terms: D001431:Bacteriological Techniques; D019411:Clinical Laboratory Techniques; D016360:Clostridioides difficile / Q000302:isolation & purification*; D003015:Clostridium Infections / Q000175:diagnosis*; D003967:Diarrhea / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D004761:Enterocolitis, Pseudomembranous / Q000175:diagnosis* / Q000276:immunology; D004768:Enterotoxins / Q000032:analysis* / Q000276:immunology; D005243:Feces / Q000382:microbiology*; D006801:Humans
chemical_list: D004768:Enterotoxins