Clostridium botulinum group I strain genotyping by 15-locus multilocus variable-number tandem-repeat analysis.
Clostridium botulinum is a taxonomic designation that encompasses a broad variety of spore-forming, Gram-positive bacteria producing the botulinum neurotoxin (BoNT). C. botulinum is the etiologic agent of botulism, a rare but severe neuroparalytic disease. Fine-resolution genetic characterization of C. botulinum isolates of any BoNT type is relevant for both epidemiological studies and forensic microbiology. A 10-locus multiple-locus variable-number tandem-repeat analysis (MLVA) was previously applied to isolates of C. botulinum type A. The present study includes five additional loci designed to better address proteolytic B and F serotypes. We investigated 79 C. botulinum group I strains isolated from human and food samples in several European countries, including types A (28), B (36), AB (4), and F (11) strains, and 5 nontoxic Clostridium sporogenes. Additional data were deduced from in silico analysis of 10 available fully sequenced genomes. This 15-locus MLVA (MLVA-15) scheme identified 86 distinct genotypes that clustered consistently with the results of amplified fragment length polymorphism (AFLP) and MLVA genotyping in previous reports. An MLVA-7 scheme, a subset of the MLVA-15, performed on a lab-on-a-chip device using a nonfluorescent subset of primers, is also proposed as a first-line assay. The phylogenetic grouping obtained with the MLVA-7 does not differ significantly from that generated by the MLVA-15. To our knowledge, this report is the first to analyze genetic variability among all of the C. botulinum group I serotypes by MLVA. Our data provide new insights into the genetic variability of group I C. botulinum isolates worldwide and demonstrate that this group is genetically highly diverse.
Histology and Molecular Biology Section, Army Medical & Veterinary Research Centre, Via Santo Stefano Rotondo 4, 00184 Rome, Italy.
Silvia
S
Fillo
Francesco
F
Giordani
Fabrizio
F
Anniballi
Olivier
O
Gorgé
Vincent
V
Ramisse
Gilles
G
Vergnaud
Julia M
JM
Riehm
Holger C
HC
Scholz
Wolf D
WD
Splettstoesser
Jasper
J
Kieboom
Jaran-Strand
JS
Olsen
Lucia
L
Fenicia
Florigio
F
Lista
D001906:Botulism / Q000382:microbiology; D003014:Clostridium botulinum / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D016000:Cluster Analysis; D005516:Food Microbiology; D005838:Genotype; D006801:Humans; D018598:Minisatellite Repeats; D017720:Molecular Epidemiology / Q000379:methods; D058889:Molecular Typing / Q000379:methods*; D057089:Pathology, Molecular / Q000379:methods; D010802:Phylogeny; D011110:Polymorphism, Genetic