The Clinical and Laboratory Impact of Upgrading Clostridioides (formerly Clostridium) difficile Infection Testing...

Clostridioides (formerly Clostridium) difficile infection (CDI) is linked to misuse of antimicrobials. The prevalence of disease varies with difficulties of establishing the diagnosis because of the lack of sensitivity and specificity of laboratory tests. The clinical impact of upgrading CDI testing from routine to molecular based-algorithm is still unclear. The aim of this study is to assess the impact of upgrading CDI testing from routine to molecular based-algorithm on the management of CDI and evaluate the role of antimicrobials on the course of CDI.

This is an observational case-study. A total of 564 patients were included from whom stool samples were tested by enzyme immunoassay (EIA) and Xpert for C. difficile. Data on the number and results of tests ordered, antimicrobial exposure, comorbidities, and treatment with metronidazole or vancomycin were collected. The main outcome measures were C. difficile tests (EIA and Xpert C. difficile Assay) and prevalence of CDI.

CDI was found in 9 and 10 cases out of 313 and 254 patients tested by the EIA and Xpert C. difficile assay, respectively, giving an overall incidence of 0.03 per 1,000 patient tested. Reduction was noted in the number of tests ordered per patient for presumptive CDI after shifting to the Xpert C. difficile assay which was not statistically significant (p-value 0.2). Also, there was less metronidazole and vancomycin therapy initiated for patients with a negative C. difficile test (p-value 0.2) observed with molecular testing.

Xpert C. difficile testing is a supportive tool for diagnosing CDI with rapid turnaround time that is helpful for patient management and initiating effective infection control measures. The clinical accuracy of the assay is still to be determined in the context of low carriage rate in the local patient population.