Resumo

GALAN, JUAN CARLOS; BAQUERO, MARÍA ROSARIO; MOROSINI, MARÍA ISABEL  e  BAQUERO, FERNANDO. High mutation rate bacteria: Risks of a high-speed life. Infect. [online]. 2006, vol.10, n.1, pp.22-29. ISSN 0123-9392.

The potential of producing genetic variability, either by mutation or by recombination, is the driving force of evolution in a living organism. Genetic variability is a quite regulated process in which bacteria tend to maintain a low mutation rate. However, a variable proportion of bacteria with a higher mutation rate than that of the modal is always present in any population. Moreover, a direct relationship exists between the proportion of mutator strains and environmental stress. In chronic infectious diseases, due to prolonged antibiotic regimens, nearly 50% of the population may be represented by mutating bacteria. Such a positive selection is due to the capacity of this type of strains to develop antibiotic resistance (100 fold higher than normal bacteria) This trait has been used as an accelerated evolution model to predict the ease of certain resistant variants to emerge as well as to infer which targets are more prone to be modified and the concomitant cost that such variability would imply to the organism. The Microbiology laboratory might then do an effort to detect mutating strains before the appearance of resistance mechanisms that may lead to therapeutic failures.

Palavras-chave : evolution; genetic recombination; mutagenesis; bacterial drug resistance.