Fecal PCR testing for detection of Clostridium perfringens and Clostridioides difficile toxin genes and other pathogens in foals with diarrhea: 28 cases.

Clostridium perfringens and Clostridioides difficile cause significant morbidity and mortality in foals. Antemortem diagnosis of C. perfringens infection has been complicated by a paucity of tests available for toxin detection. Fecal PCR panels have assays for a variety of C. perfringens toxin gene sequences as well as for several other foal gastrointestinal pathogens. We evaluated results of a comprehensive fecal diarrhea PCR panel in 28 foals that had been presented to a referral hospital because of diarrhea. Sixteen (57%) foals were positive for C. perfringens and/or C. difficile toxin gene sequences on fecal PCR, including 3 foals positive for NetF toxin. These foals were younger (p = 0.0029) and had higher hematocrits (p = 0.0087), hemoglobin (p = 0.0067), and red blood cell concentrations (p = 0.028) than foals with diarrhea that tested negative for clostridial toxins. The foals had lower total protein concentrations (p = 0.045) and were more likely to have band neutrophils on a CBC (p = 0.013; OR: 16.2). All 3 foals with NetF toxin gene sequences detected in feces survived to discharge, indicating that diarrhea caused by NetF toxigenic C. perfringens isolates is not uniformly fatal.