Enterotoxin plasmid from Clostridium perfringens is conjugative.

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Clostridium perfringens enterotoxin (CPE) is a key virulence factor in C. perfringens type A food poisoning and other gastrointestinal illnesses.
• The enterotoxin gene (cpe) is located on the chromosome in food-borne isolates but on a plasmid in non-food-borne and veterinary isolates.

Purpose of the Study:

• To determine if the cpe-carrying plasmid (pMRS4969) in C. perfringens is self-transmissible via conjugation.
• To investigate the mechanism and potential clinical implications of cpe plasmid transfer.

Main Methods:

• Conjugation experiments were performed using a C. perfringens strain with a modified cpe plasmid (pMRS4969) as a donor and cpe-negative strains as recipients.
• Transconjugants were analyzed using PCR, pulsed-field gel electrophoresis, and Southern hybridization.
• Plasmid similarity was assessed by hybridization with fragments of the C. perfringens tetracycline resistance plasmid pCW3.

Main Results:

• The entire pMRS4969 plasmid, containing the chloramphenicol resistance gene (catP) marker, was successfully transferred to recipient C. perfringens strains.
• Plasmid transfer occurred via conjugation, requiring cell-to-cell contact and being DNase resistant.
• Evidence suggests sequence similarity between the cpe plasmid pMRS4969 and the C. perfringens tetracycline resistance plasmid pCW3.

Conclusions:

• The cpe plasmid is conjugative, capable of transferring itself between C. perfringens strains.
• In vivo transfer of the cpe plasmid could lead to the emergence of pathogenic C. perfringens strains from commensal populations.
• Understanding plasmid transfer is crucial for controlling C. perfringens-associated gastrointestinal diseases.