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Clonal origin of the type 37 Streptococcus pneumoniae.
Microbial Drug Resistance (Larchmont, N.Y.)
|March 29, 2001
Summary
Type 37 Streptococcus pneumoniae strains frequently generated non-typable variants in lab cultures. Genetic analysis revealed inactivating mutations in the tts gene, suggesting a single clone spread globally.
Area of Science:
- Microbiology
- Genetics
- Epidemiology
Background:
- Streptococcus pneumoniae causes significant global disease burden.
- Type 37 strains possess a specific tts gene for capsular polysaccharide.
- Understanding strain evolution is crucial for public health.
Purpose of the Study:
- Investigate the genetic stability of type 37 Streptococcus pneumoniae.
- Identify mechanisms leading to non-typable variants.
- Determine the clonal origin and global spread of type 37 strains.
Main Methods:
- In vitro cultivation of type 37 S. pneumoniae isolates.
- Polymerase chain reaction (PCR) amplification and sequencing of the tts gene.
- Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST).
Main Results:
- Type 37 S. pneumoniae frequently produced non-typable variants during cultivation.
- Sequencing identified diverse inactivating mutations within the tts gene of mutants.
- PFGE and MLST indicated that all type 37 isolates belong to a single clonal complex.
Conclusions:
- The tts gene in type 37 S. pneumoniae is prone to inactivating mutations.
- Non-typable variants arise readily under laboratory conditions.
- Evidence strongly suggests a single, ancient clone of type 37 S. pneumoniae has disseminated worldwide.