Performance of Different Laboratory Methods for Detection of Clostridium difficile in Animal Samples

Clostridium difficile is a well-known enteric pathogen causing antibiotic-associated diarrhea and pseudomembranous colitis among humans. Lately, C. difficile has emerged to cause enteric problems in food producing animals, horses and household pets particularly young ones. This study was conducted to investigate the performance of different laboratory diagnostic methods for Clostridium difficile in veterinary field. For this purpose, ninety fecal samples collected from diarrheic sheep, goats and chickens, were examined for the detection of C. difficile using three laboratory methods: direct Polymerase chain reaction (PCR) on DNA extracted from fecal samples, conventional culture followed by molecular confirmation of isolates and glutamate dehydrogenase (GDH) ELISA on feces. The detection rates of C. difficile were 45.6%, 16.7% and 8.9% by direct PCR, conventional culture followed by molecular confirmation of isolates and GDH-ELISA, respectively. Direct PCR yielded the highest detection rate, however, false negative results were recorded in 3 samples being positive by culture method, whereas, all GDH-ELISA positive samples were also positive by the other techniques. In conclusion, Direct PCR on DNA extracted from fecal samples of animals showed the highest detection rate nevertheless false negative results cannot be ruled out.