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Updated: Sep 22, 2025
Replication of the Ordered, Nonredundant Library of Pseudomonas aeruginosa strain PA14 Transposon Insertion Mutants
Published on: May 4, 2018
Polymicrobial infections can select against Pseudomonas aeruginosa mutators because of quorum-sensing trade-offs
Adela M Luján1,2,3,4, Steve Paterson5, Elze Hesse6
1ESI and CEC, Biosciences, University of Exeter, Penryn, UK. adem.lujan@gmail.com.
Abstract:
Bacteria with increased mutation rates (mutators) are common in chronic infections and are associated with poorer clinical outcomes, especially in the case of Pseudomonas aeruginosa infecting cystic fibrosis (CF) patients. There is, however, considerable between-patient variation in both P. aeruginosa mutator frequency and the composition of co-infecting pathogen communities. We investigated whether community context might affect selection of mutators. Using an in vitro CF model community, we show that P. aeruginosa mutators were favoured in the absence of other species but not in their presence. This was because there were trade-offs between adaptation to the biotic and abiotic environments (for example, loss of quorum sensing and associated toxin production was beneficial in the latter but not the former in our in vitro model community) limiting the evolvability advantage of an elevated mutation rate. Consistent with a role of co-infecting pathogens selecting against P. aeruginosa mutators in vivo, we show that the mutation frequency of P. aeruginosa population was negatively correlated with the frequency and diversity of co-infecting bacteria in CF infections. Our results suggest that co-infecting taxa can select against P. aeruginosa mutators, which may have potentially beneficial clinical consequences.
Insights
Bacterial mutators, common in chronic infections like cystic fibrosis (CF), are suppressed by co-infecting microbes. This suggests that diverse microbial communities may offer clinical benefits by limiting the spread of high-mutation-rate pathogens.
Area of Science:
- Microbiology
- Evolutionary Biology
- Infectious Diseases
Background:
- Bacteria with elevated mutation rates, known as mutators, are prevalent in chronic infections and linked to worse clinical outcomes.
- Pseudomonas aeruginosa mutators are frequently found in cystic fibrosis (CF) patients, but their prevalence varies significantly between patients and with co-infecting microbial communities.
Purpose of the Study:
- To investigate the impact of microbial community context on the selection and prevalence of Pseudomonas aeruginosa mutators.
- To determine if the presence of other species influences the evolutionary advantage of increased mutation rates in P. aeruginosa.
Main Methods:
- Utilized an in vitro cystic fibrosis (CF) model community to assess the selection of P. aeruginosa mutators under different conditions.
- Analyzed clinical data from CF infections to correlate P. aeruginosa mutation frequency with the frequency and diversity of co-infecting bacteria.
Main Results:
- P. aeruginosa mutators were favored in isolation but not when other species were present in the in vitro CF model.
- Trade-offs between adaptation to biotic and abiotic environments limited the evolvability advantage of mutators in a community setting.
- In clinical CF infections, P. aeruginosa mutation frequency showed a negative correlation with the frequency and diversity of co-infecting bacteria.
Conclusions:
- Co-infecting microbial taxa can exert selective pressure against P. aeruginosa mutators.
- The presence of diverse co-infecting bacteria may have beneficial clinical consequences by suppressing mutator strains.
- Community context plays a crucial role in the evolution and prevalence of bacterial mutators in chronic infections.
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