The most common toxinotypes of the bacterium Clostridium perfringens in small ruminants and their resistance to antibiotics

Infection with the bacterium C. perfringens in sheep and goat herds leads to considerable losses. The most common diseases in small ruminants caused by this bacterium are pulpy kidney disease, enterotoxaemia, yellow lamb disease, and necrotic enteritis. C. perfringens is widely distributed in the environment and is part of the intestinal microbiota of humans and animals. When physiological conditions in the body change, it begins to produce toxins that lead to various pathological changes. Depending on the toxins it produces, it is classified into seven types (A–G), defined based on the presence of genes encoding the CPA toxin (all types), CPB toxin (type B and type C), ETX toxin (type B and D), ITX toxin (type E), CPE toxin (type F) and NetB toxin (type G). Strains A and D are most commonly associated with enterotoxaemia in small ruminants. According to the available literature, C. perfringens toxinotype A is most frequently isolated in small ruminant herds. In addition to toxin genes, antibiotic resistance genes also play an important role in bacterial survival. Of the genetic determinants of antimicrobial resistance discovered to date, most are associated with the following antimicrobial drugs: bacitracin (bcrR gene), tetracyclines (tet genes), macrolides (erm genes), lincosamides (erm and lnu genes), streptogramins (erm genes) and chloramphenicol (cat genes). Due to sudden death after the onset of symptoms and the economic unprofitability, very few results are available on antibiotic resistance of C. perfringens in small ruminants. Therefore, it has proven to be more economical and effective to work on prevention than on treatment. Since there is no vaccine against enterotoxaemia in Croatia, prevention of the disease is difficult.