Citation
High frequency of hypermutable Pseudomonas aeruginosa in cystic fibrosis lung infection
TL;DR
20-40% of P. aeruginosa strains in CF lungs are hypermutators
This landmark study demonstrated that 20-40% of Pseudomonas aeruginosa strains in cystic fibrosis lungs are hypermutators with defective DNA repair genes. It provides clinical evidence that high mutation rates are favored when organisms face constant selective pressure (antibiotics, immune attack).
The cystic fibrosis case study in the chapter draws directly on this research to illustrate the evolutionary arms race between pathogens and treatments, and why mutator phenotypes - though costly long-term - provide survival advantages in hostile environments.
Key Findings from Oliver et al. (2000)
- 20-40% of P. aeruginosa strains in CF lungs are hypermutators
- Hypermutators have defective mutS/mutL DNA repair genes
- Mutation rates are 100-1000x higher than normal strains
- Mutators dominate because antibiotic resistance provides immediate survival benefit
- Demonstrates mutator phenotype favored under constant selective pressure