Abstract: This disclosure provides materials and methods for reducing production of virulence factors in C. perfringens and or other pathogenic clostridia with related Agr-like QS systems using compounds that interfere with the Agr-like quorum sensing (QS) system. For example, Agr-like QS system inhibitors based on peptidomimetic compounds of the Agr-like QS system signaling peptide (SP) or the SP receptor of C. perfringens, and methods of using the Agr-like QS system inhibitors to prevent, treat, or ameliorate a disease associated with C. perfringens infection are provided.

Abstract: Escherichia coli strains that produce recombinant Clostridium perfringens type A enterotoxin toxoids from a Clostridium perfringens type A enterotoxin gene fragment encoding the Clostridium perfringens type A enterotoxin binding domain subcloned into an expression vector for forming plasmids are disclosed. The Clostridium perfringens type A enterotoxin toxoids of this invention recognize, irreversibly bind to and saturate receptor sites on intestinal membranes and, thus effectively compete for these receptor sites with Clostridium perfringens type A enterotoxin. The toxoids of this invention may be used to treat the symptoms of Clostridium perfringens food poisoning in patients. Vaccines are also disclosed that may be used to prevent the symptoms of Clostridium perfringens food poisoning in patients. Processes for preparing the plasmids and toxoids of this invention and for using the toxoids and vaccines of this invention are also provided.