title: Clostridium botulinum strains producing BoNT/F4 or BoNT/F5.
abstract: Botulinum neurotoxin type F (BoNT/F) may be produced by Clostridium botulinum alone or in combination with another toxin type such as BoNT/A or BoNT/B. Type F neurotoxin gene sequences have been further classified into seven toxin subtypes. Recently, the genome sequence of one strain of C. botulinum (Af84) was shown to contain three neurotoxin genes (bont/F4, bont/F5, and bont/A2). In this study, eight strains containing bont/F4 and seven strains containing bont/F5 were examined. Culture supernatants produced by these strains were incubated with BoNT/F-specific peptide substrates. Cleavage products of these peptides were subjected to mass spectral analysis, allowing detection of the BoNT/F subtypes present in the culture supernatants. PCR analysis demonstrated that a plasmid-specific marker (PL-6) was observed only among strains containing bont/F5. Among these strains, Southern hybridization revealed the presence of an approximately 242-kb plasmid harboring bont/F5. Genome sequencing of four of these strains revealed that the genomic backgrounds of strains harboring either bont/F4 or bont/F5 are diverse. None of the strains analyzed in this study were shown to produce BoNT/F4 and BoNT/F5 simultaneously, suggesting that strain Af84 is unusual. Finally, these data support a role for the mobility of a bont/F5-carrying plasmid among strains of diverse genomic backgrounds.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Raphael
authors.forename: Marite
authors.initials: M
authors.lastname: Bradshaw
authors.forename: Suzanne R
authors.initials: SR
authors.lastname: Kalb
authors.forename: Lavin A
authors.initials: LA
authors.lastname: Joseph
authors.forename: Carolina
authors.initials: C
authors.lastname: Lúquez
authors.forename: John R
authors.initials: JR
authors.lastname: Barr
authors.forename: Eric A
authors.initials: EA
authors.lastname: Johnson
authors.forename: Susan E
authors.initials: SE
authors.lastname: Maslanka
mesh_terms: D001905:Botulinum Toxins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D003014:Clostridium botulinum / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics / Q000378:metabolism
chemical_list: D001905:Botulinum Toxins; C096321:botulinum toxin type F