title: Identification of novel Clostridium perfringens type E strains that carry an iota toxin plasmid with a functional enterotoxin gene.
abstract: Clostridium perfringens enterotoxin (CPE) is a major virulence factor for human gastrointestinal diseases, such as food poisoning and antibiotic associated diarrhea. The CPE-encoding gene (cpe) can be chromosomal or plasmid-borne. Recent development of conventional PCR cpe-genotyping assays makes it possible to identify cpe location (chromosomal or plasmid) in type A isolates. Initial studies for developing cpe genotyping assays indicated that all cpe-positive strains isolated from sickened patients were typable by cpe-genotypes, but surveys of C. perfringens environmental strains or strains from feces of healthy people suggested that this assay might not be useful for some cpe-carrying type A isolates. In the current study, a pulsed-field gel electrophoresis Southern blot assay showed that four cpe-genotype untypable isolates carried their cpe gene on a plasmid of ∼65 kb. Complete sequence analysis of the ∼65 kb variant cpe-carrying plasmid revealed no intact IS elements and a disrupted cytosine methyltransferase (dcm) gene. More importantly, this plasmid contains a conjugative transfer region, a variant cpe gene and variant iota toxin genes. The toxin genes encoded by this plasmid are expressed based upon the results of RT-PCR assays. The ∼65 kb plasmid is closely related to the pCPF4969 cpe plasmid of type A isolates. MLST analyses indicated these isolates belong to a unique cluster of C. perfringens. Overall, these isolates carrying a variant functional cpe gene and iota toxin genes represent unique type E strains.
authors.affiliation: Department of Microbiology, Wakayama Medical University School of Medicine, Wakayama, Japan. kazuaki@wakayama-med.ac.jp
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Natsuko
authors.initials: N
authors.lastname: Yumine
authors.forename: Kanako
authors.initials: K
authors.lastname: Mimura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nagahama
authors.forename: Jihong
authors.initials: J
authors.lastname: Li
authors.forename: Bruce A
authors.initials: BA
authors.lastname: McClane
authors.forename: Shigeru
authors.initials: S
authors.lastname: Akimoto
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D003016:Clostridium perfringens / Q000235:genetics*; D004768:Enterotoxins / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; C035598:enterotoxin, Clostridium; C050737:iota toxin, Clostridium perfringens; D036002:ADP Ribose Transferases