Detecting C. difficile and C. perfringens toxins in foals

Abstract

REASONS FOR PERFORMING THE STUDY: Toxin detection and screening could contribute to knowledge of the transmission patterns, risk factors and epidemiology of Clostridium difficile and Clostridium perfringens. OBJECTIVE: To isolate C. difficile and C. perfringens and to detect A/B toxins in faecal samples from diarrhoeic and nondiarrhoeic foals. STUDY DESIGN: Cross-sectional observational study. METHODS: A total of 153 samples from foals were collected: 139 samples from farms and 14 samples from diarrhoeic foals admitted to a veterinary hospital. The A/B toxins were detected by cytotoxicity assay. All suspected colonies of C. perfringens were subjected to polymerase chain reaction for detection of the major toxin genes (α, β, ε and ι) and for detection of β2-, NetB- and enterotoxin-encoding genes. Furthermore, C. difficile and C. perfringens isolates were evaluated for in vitro antimicrobial susceptibility. RESULTS: Seven of 153 (4.6%) samples, all from diarrhoeic foals, were positive for C. difficile A/B toxin. Of these, 5 of 14 (35.7%) were from hospitalised foals, and only 2 of 63 (3.2%) diarrhoeic foal samples were from farms (P = 0.002). Clostridium perfringens was isolated from 31 (20.3%) foals, of which 21 of 76 (27.6%) were diarrhoeic and 10 of 76 (13.2%) were nondiarrhoeic, demonstrating a difference between these 2 groups (P = 0.045). Only 4 strains were positive for the β2-encoding gene (cpb2). All C. difficile and C. perfringens isolates were susceptible to metronidazole and vancomycin. CONCLUSIONS: The present report highlights the need for laboratory diagnostics to differentiate C. difficile-associated infection in foals from other causes of diarrhoea to facilitate adequate antimicrobial therapy. POTENTIAL RELEVANCE: More studies are needed to clarify the role of C. perfringens as a primary agent of diarrhoea in foals.