Antibiotic resistance plasmids and mobile genetic elements of Clostridium perfringens

Clostridium perfringens is an anaerobic bacterium that is a major human and animal pathogen. The key features of C. perfringens-mediated infections are that disease pathogenesis involves the production of protein toxins and that disease epidemiology generally involves the production of environmentally resistant endospores. Many of the toxins involved in these diseases are encoded on conjugative plasmids that are closely related to the paradigm tetracycline resistance plasmid pCW3. This plasmid encodes the Tet(P) tetracycline resistance determinant, and the tcp locus, which mediates conjugative transfer and is also present on the toxin plasmids. In addition to being directly responsible for the widely dispersed distribution of the Tet(P) determinant, which is not located on a transposable genetic element, this family of conjugative plasmids facilitates the spread of other mobile resistance elements. These elements include the chloramphenicol resistance integrative mobilisable elements typified by Tn4451, the bacitracin resistance integrative conjugative element typified by ICECp1, and the lincomycin resistance transferable insertion sequence typified by tISCpe8. Each of these elements are found on conjugative plasmids that are closely related to pCW3, providing evidence that this large plasmid family has a key role in the distribution of antibiotic resistance genes in C. perfringens.