Hospital based incidence of clostridium difficile enterocolitis and cross reactivity of the latex agglutination test

In order to determine the prevalence and characteristics of antibiotic-associated Clostridium difficile enterocolitis, a total of 2476 specimens from 2356 patients were examined. Of these 224 [9.5%] were positive, 158 [70%] of them occurring in organ transplant, bone marrow transplant or neutropenic patients. Antibiotic-associated colitis due to enterotoxigenic C. difficile was diagnosed by use of cytotoxin assay [CTA]. During a previous study, CTA was compared with a commercial latex agglutination [LA] test and gave a high frequency of false positives. Sixteen of these 31 false positive specimens also had a bacterial pathogen or parasite present. Since a wide range of microbial pathogens/parasites are found in Saudi patients, we also tested stool supernatants from a further 107 patients harboring enteric microbial pathogens/parasites to determine the cross-reactivity of a rapid latex agglutination kit [LA] with these organisms. Only one specimen which grew Salmonella enteritidis gave a false-positive reaction. Since the reagents in the LA test also react with non-toxigenic strains of C. difficile and other anaerobes, the method could be used only as a rapid screening procedure and positive findings should be confirmed by a specific test. Running title: C. difficile toxin enterocolitis