title: Virulence Plasmids of Spore-Forming Bacteria.
abstract: Plasmid-encoded virulence factors are important in the pathogenesis of diseases caused by spore-forming bacteria. Unlike many other bacteria, the most common virulence factors encoded by plasmids in Clostridium and Bacillus species are protein toxins. Clostridium perfringens causes several histotoxic and enterotoxin diseases in both humans and animals and produces a broad range of toxins, including many pore-forming toxins such as C. perfringens enterotoxin, epsilon-toxin, beta-toxin, and NetB. Genetic studies have led to the determination of the role of these toxins in disease pathogenesis. The genes for these toxins are generally carried on large conjugative plasmids that have common core replication, maintenance, and conjugation regions. There is considerable functional information available about the unique tcp conjugation locus carried by these plasmids, but less is known about plasmid maintenance. The latter is intriguing because many C. perfringens isolates stably maintain up to four different, but closely related, toxin plasmids. Toxin genes may also be plasmid-encoded in the neurotoxic clostridia. The tetanus toxin gene is located on a plasmid in Clostridium tetani, but the botulinum toxin genes may be chromosomal, plasmid-determined, or located on bacteriophages in Clostridium botulinum. In Bacillus anthracis it is well established that virulence is plasmid determined, with anthrax toxin genes located on pXO1 and capsule genes on a separate plasmid, pXO2. Orthologs of these plasmids are also found in other members of the Bacillus cereus group such as B. cereus and Bacillus thuringiensis. In B. thuringiensis these plasmids may carry genes encoding one or more insecticidal toxins.
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Vicki
authors.initials: V
authors.lastname: Adams
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA.
authors.forename: Jihong
authors.initials: J
authors.lastname: Li
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Wisniewski
authors.affiliation: California Animal Health and Food Safety Laboratory, San Bernardino Branch, School of Veterinary Medicine, University of California-Davis, San Bernardino, CA.
authors.forename: Francisco A
authors.initials: FA
authors.lastname: Uzal
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Moore
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: McClane
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Julian I
authors.initials: JI
authors.lastname: Rood
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D004725:Endospore-Forming Bacteria / Q000235:genetics* / Q000472:pathogenicity; D010957:Plasmids; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D037521:Virulence Factors