Publicação
The role of fitness frequency-dependent in the evolution of antibiotic resistance
| Resumo: | Antibiotic resistance is, usually, associated with fitness costs for the bacteria. Therefore, it is expected that if one competes a resistant bacterial strain with an otherwise isogenic susceptible strain in an antibiotic free environment, resistant bacteria will be eliminated. Here, I report the occurrence of stabilizing frequency-dependent selection in 43% of a set of antibiotic resistant strains. Stabilizing frequency-dependent selection may promote the maintenance of a stable polymorphism between resistant and susceptible bacteria. If resistant bacteria are rare, their fitness is higher than that of the susceptible strain. If resistant bacteria are the majority in the competition assay, their fitness is smaller than that of the susceptible strain. This enables a stable coexistence between sensitive and resistant strains. Genetic and ecological causes of frequency-dependent selection were investigated. The demonstration of frequency-dependent selection involving drug resistance strains implies that antibiotic resistant bacteria will not be easily eliminated or reversed upon reduction of antibiotic use. This reveals a worrying scenario for the eradication of antibiotic resistance. |
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| Autores principais: | Alves, Diana Ribeiro, 1987- |
| Assunto: | Microbiologia Resistência aos antibióticos Escherichia coli Teses de mestrado - 2010 |
| Ano: | 2010 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Antibiotic resistance is, usually, associated with fitness costs for the bacteria. Therefore, it is expected that if one competes a resistant bacterial strain with an otherwise isogenic susceptible strain in an antibiotic free environment, resistant bacteria will be eliminated. Here, I report the occurrence of stabilizing frequency-dependent selection in 43% of a set of antibiotic resistant strains. Stabilizing frequency-dependent selection may promote the maintenance of a stable polymorphism between resistant and susceptible bacteria. If resistant bacteria are rare, their fitness is higher than that of the susceptible strain. If resistant bacteria are the majority in the competition assay, their fitness is smaller than that of the susceptible strain. This enables a stable coexistence between sensitive and resistant strains. Genetic and ecological causes of frequency-dependent selection were investigated. The demonstration of frequency-dependent selection involving drug resistance strains implies that antibiotic resistant bacteria will not be easily eliminated or reversed upon reduction of antibiotic use. This reveals a worrying scenario for the eradication of antibiotic resistance. |
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