NetF-producing Clostridium perfringens: Clonality and plasmid pathogenicity loci analysis.

Area of Science:

• Veterinary Microbiology
• Bacterial Pathogenesis
• Genomics

Background:

• Clostridium perfringens NetF toxin is a key virulence factor in foal necrotizing enteritis and canine acute hemorrhagic diarrhea.
• NetF is encoded on a pathogenicity locus within a conjugative plasmid, often alongside other toxins like NetE, CPE, and CPB2.

Purpose of the Study:

• To investigate if all NetF-producing Clostridium perfringens strains share a common plasmid profile.
• To determine the conservation of NetF and CPE pathogenicity loci across these strains.
• To evaluate clonal relationships among NetF-producing strains.

Main Methods:

• Whole-genome sequencing of 15 equine and 15 canine NetF-positive C. perfringens isolates using Illumina Hiseq2000.
• Core genome multilocus sequence typing (cgMLST) to assess clonal relationships.

Main Results:

• All NetF-producing strains exhibited a common plasmid profile.
• Pathogenicity loci for NetF and CPE were conserved across all sequenced strains.
• cgMLST revealed two distinct clonal complexes; one lacked the pNetG plasmid, and minor plasmid differences were noted between complexes.

Conclusions:

• NetF-producing Clostridium perfringens strains maintain a conserved plasmid profile and pathogenicity loci.
• Distinct clonal complexes exist within NetF-producing strains, influencing plasmid carriage (e.g., pNetG).
• Understanding these genetic elements is vital for controlling diseases caused by these pathogens.