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Host population structure and treatment frequency maintain balancing selection on drug resistance.

ABSTRACT: It is a truism that antimicrobial drugs select for resistance, but explaining pathogen- and population-specific variation in patterns of resistance remains an open problem. Like other common commensals, Streptococcus pneumoniae has demonstrated persistent coexistence of drug-sensitive and drug-resistant strains. Theoretically, this outcome is unlikely. We modelled the dynamics of competing strains of S. pneumoniae to investigate the impact of transmission dynamics and treatment-induced selective pressures on the probability of stable coexistence. We find that the outcome of competition is extremely sensitive to structure in the host population, although coexistence can arise from age-assortative transmission models with age-varying rates of antibiotic use. Moreover, we find that the selective pressure from antibiotics arises not so much from the rate of antibiotic use per se but from the frequency of treatment: frequent antibiotic therapy disproportionately impacts the fitness of sensitive strains. This same phenomenon explains why serotypes with longer durations of carriage tend to be more resistant. These dynamics may apply to other potentially pathogenic, microbial commensals and highlight how population structure, which is often omitted from models, can have a large impact.

SUBMITTER: Cobey S

PROVIDER: S-EPMC5582124 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature

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Host population structure and treatment frequency maintain balancing selection on drug resistance.

Cobey Sarah S Baskerville Edward B EB Colijn Caroline C Hanage William W Fraser Christophe C Lipsitch Marc M

Journal of the Royal Society, Interface 20170801 133

It is a truism that antimicrobial drugs select for resistance, but explaining pathogen- and population-specific variation in patterns of resistance remains an open problem. Like other common commensals, <i>Streptococcus pneumoniae</i> has demonstrated persistent coexistence of drug-sensitive and drug-resistant strains. Theoretically, this outcome is unlikely. We modelled the dynamics of competing strains of <i>S. pneumoniae</i> to investigate the impact of transmission dynamics and treatment-ind ...[more]

PMID: 28835542

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Host population structure and treatment frequency maintain balancing selection on drug resistance.

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Host population structure and treatment frequency maintain balancing selection on drug resistance.

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