Phylogenetic analysis of Clostridium botulinum type A by multi-locus sequence typing
Mark J Jacobson1, Guangyun Lin1, Thomas S Whittam2
1Department of Bacteriology, Food Research Institute, University of Wisconsin-Madison, Madison, WI 53706, USA.
Microbiology (Reading, England)
|August 1, 2008
Summary
Multi-locus sequence typing (MLST) clarifies the evolutionary relationships within Clostridium botulinum type A. This method effectively distinguishes distinct lineages, revealing a complex phylogenetic structure for this bacterium.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genomics
Background:
- The genus Clostridium exhibits poorly understood phylogenetic and evolutionary relationships.
- Accurate and reproducible methods are needed to distinguish Clostridium lineages.
- Multi-locus sequence typing (MLST) is a proven technique for bacterial evolutionary and strain studies.
Purpose of the Study:
- To apply MLST for evaluating evolutionary lineages within Clostridium botulinum serotype A.
- To investigate the phylogenetic structure of C. botulinum type A, which has shown multiple subtypes.
Main Methods:
- Evaluated 14 housekeeping genes for amplification and sequencing in Clostridium botulinum type A.
- Selected seven optimal genes (mdh, aceK, rpoB, aroE, hsp60, oppB, recA) for MLST analysis.
- Analyzed 73 C. botulinum type A strains producing botulinum neurotoxin subtypes A1-A4.
Main Results:
- Identified 24 distinct sequence types among the 73 analyzed C. botulinum type A strains.
- Demonstrated that C. botulinum type A is not monophyletic but comprises distinct evolutionary lineages.
- Validated the utility of the selected seven-gene MLST scheme for phylogenetic resolution.
Conclusions:
- MLST is an effective and reproducible method for elucidating evolutionary lineages in Clostridium botulinum.
- The findings reveal a complex phylogenetic structure for C. botulinum type A.
- This MLST strategy is applicable for phylogenetic studies and typing of other Clostridium species and serotypes.
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