Multilocus sequence typing analyses of Clostridium perfringens type A strains harboring tpeL and netB genes

Clostridium perfringens is an anaerobic bacterium ubiquitous in various environments, especially in soil and the gastrointestinal tract of healthy humans and animals. In this study, multilocus sequence typing protocol was used to investigate genotypic relationships among 40 C. perfringens strains isolated from humans and broiler chicken with necrotic enteritis [NE]. The results indicated a few clonal populations, mainly observed in human strains, with 32.5% of all strains associated with one of three clonal complexes and 30 sequences types. The CC-1 cluster showed an interesting and unexpected result because it contained seven strains [six from animals and one of human origin]. Detection assays for toxin genes tpeL and netB were also performed. The netB gene was only observed in 7.5% of the strains from healthy human. The toxin gene tpeL was detected in 22.5% of the C. perfringens strains isolated from three individuals and in six broilers with NE. Our study describes the role of some C. perfringens strains of human origin acting as reservoirs of virulence genes and sources of infection. In addition, the strains of human and animal origin were found to be genetically distinct but phylogenetically close, and the human strains showed more diversity than the animal strains.