Toxigenic Profile ofClostridium perfringensStrains Isolated from Natural Ingredient Laboratory Animal Diets

Clostridium perfringens is an anaerobic, gram-positive, spore-forming bacterium that ubiquitously inhabits a wide variety of natural environments including the gastrointestinal tract of humans and animals. C. perfringens is an opportunistic enteropathogen capable of producing at least 20 different toxins in various combinations. Strains of C. perfringens are currently categorized into seven toxinotypes (A, B, C, D, E, F & G) based on the presence/absence of four major toxins (alpha, beta, epsilon & iota) and two minor toxins (enterotoxin & netB). Each toxinotype is associated with specific histotoxic and enteric diseases. The Quality Assurance Laboratory (QAL) at the National Institute of Environmental Health Sciences (NIEHS) screens incoming animal feeds for aerobic, enteric pathogens, such as Salmonella spp. and E. coli . Recently, QAL has incorporated anaerobic screening of incoming animal feeds. To date, the lab has isolated numerous Clostridiu m species, including C. perfringens , from 23 lots of natural-ingredient laboratory animal diets. Importance Published reports of Clostridium perfringens isolation from laboratory animal feeds could not be found in the literature. Therefore, we performed a toxin profile screening of our isolated strains of C. perfringens to determine which toxinotypes were present in our laboratory animal diets. As studies progress with immunocompromised strains, gnotobiotic models, and animals with perturbed gut flora, the presence of C. perfringens could potentially lead to infection, disease and mortality which would substantiate the need to properly eliminate the bacterium and its spores from diets given to high risk animal populations.