Objectives: this study was undertaken to find out the role of stool culture and toxin A and B detection in the diagnosis of AAD due to Cl.difficile. We wanted to know which of these two methods could be the most optimal procedure in combination with toxin A detection test to provide the most accurate diagnosis among hosptalized patients. An evaluation of the riskfactors and current treatment at our hospital was also performed.
Methods: Over a period of 14 months, 767 liquid or semi-liquid faecal samples from hospitalized patients suspected for CDAD were collected. All samples were tested with Toxin A/B test by ELISA (Meridian Bioscience), and cultured on cycloserin cefoxitim fructose agar stored anerobically. Colonies were idientified by standard laboratory techniques, and further tested with toxin A/B test and toxin A test (Oxoid) to confirm their toxigenicity, and the presence of toxin A negative/toxin B positive strains.
Results: A total of 65 samples from 46 patients tested positive using the Toxin A/B test, and 26 were positive on culture. All 26 colonies were toxin-producing. Twentythree of the samples were positive on all 3 tests. Interestingly 13 (20%) samples were Toxin A/B positive and Toxin A negative, indicating the presence of toxin A-/B+ strains of Cl.diff. Three patients recieved no antibiotics but chemotherapy prior to infection.
Conclusion: Detection of Cl.diff. by culture did not prove to be a sensitive method in our study, obviously due to poor sending and storing techniques of samples, prior to application on agar. Toxin A/B test could be important in identifying toxin A-/B positive strains of Cl.diff. A relativly large proportion of patients recieved meropenem prior to infection, an antibiotic not widley used in CDAD, but increasingly administered at our hospital. Conservative and specific use of antibiotics in correct dosages should always be employed, and should decrease the incidence of AAD and thereby CDAD.