Ribotyping as an identification tool for Clostridium botulinum strains causing human botulism.
Ribotyping was used for characterisation of 68 Clostridium botulinum strains and five related Clostridium species to determine the applicability of this method for identification of species causing human botulism. Thirteen restriction enzymes were initially tested for suitability for ribotyping of C. botulinum, of which EcoRI and HindIII were selected. Both enzymes clearly differentiated between proteolytic (group I) and a nonproteolytic (group II) strains of C. botulinum, and can be recommended for Group/species identification. Using a commercial software package (GelCompar), a numerical analysis of the discriminatory abilities of EcoRI and HindIII ribotyping within and between the two C. botulinum groups was performed. EcoRI had the higher discriminatory index (0.982), but the ribopatterns generated with group II strains were partly muddled and difficult to interpret. All HindIII ribopatterns were easy to analyse and the discriminatory index for all strains was almost equally high (0.954), whereas this enzyme did not discriminate well between group I isolates. The Clostridium strains diverged at 35+/-13% (mean+/-standard deviation) Dice similarity in dendrograms based on cluster analysis of the ribotyping results. These findings are in good agreement with taxonomical ribotyping studies with other bacterial genera, indicating that ribotyping is a highly suitable method for C. botulinum species identification.
Hielm
S
S
Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, Helsinki University, Finland. sebastian.hielm@helsinki.fi
Björkroth
J
J
Hyytiä
E
E
Korkeala
H
H
D015139:Blotting, Southern; D001905:Botulinum Toxins / Q000032:analysis; D001906:Botulism / Q000382:microbiology* / Q000517:prevention & control; D003014:Clostridium botulinum / Q000145:classification* / Q000235:genetics; D003016:Clostridium perfringens / Q000145:classification / Q000235:genetics; D016000:Cluster Analysis; D015246:Deoxyribonuclease EcoRI / Q000737:chemistry; D015247:Deoxyribonuclease HindIII / Q000737:chemistry; D004587:Electrophoresis, Agar Gel; D006801:Humans; D009693:Nucleic Acid Hybridization; D009716:Numerical Analysis, Computer-Assisted; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012329:RNA, Bacterial / Q000737:chemistry*; D012335:RNA, Ribosomal / Q000737:chemistry*
D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D015246:Deoxyribonuclease EcoRI; D015247:Deoxyribonuclease HindIII; D001905:Botulinum Toxins