Evaluation of an immunochromatographic test for the detection of glutamate dehydrogenase for the diagnosis of Clostridioides (Clostridium) difficile infection in dogs.

This study aimed to evaluate an immunochromatographic test used to detect glutamate dehydrogenase (GDH) for the diagnosis of Clostridium difficile infection (CDI) in dogs. Fecal samples of 119 diarrheic dogs were subjected to toxigenic culture as the "gold standard" method and to GDH detection (Ecodiagnostica, Brazil). Samples positive for toxigenic C. difficile strains and those positive in the GDH test were also subjected to A/B toxin detection using an enzyme immunoassay kit (C. difficile Tox A/B II, Techlab Inc., USA). Sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) were measured for GDH detection and compared with the toxigenic culture results. A total of 19 (15.9%) dogs were positive for toxigenic C. difficile. Of these, 10 (52.6%) dogs were positive for A/B toxins using the enzyme immunoassay kit and 18 (15.2%) were positive in the GDH test, leading to a sensitivity and NPV of 89.4% and 97.9%, respectively. Three animals, two of which were colonized with non-toxigenic strains, were positive for GDH, though not confirmed with CDI, resulting in a high specificity (97%) and PPV (85%). The results suggest that the lateral flow test for GDH detection could be a useful method for diagnosing CDI in dogs, similar to that previously described for humans and other animal species.