Question

In hospitals where many tuberculosis patients are treated the population of the tuberculosis mycobacteria may be constituted of multiresistant (to antibiotics) strains. How does the synthetic theory of evolution explain this fact?

Answer 1

The appearance of multiresistant strains of pathogenic parasites in hospitals, for example, of multiresistant tuberculosis bacteria, can be explained by the synthetic theory of evolution.

As in any environment, TB bacteria in hospitals undergo changes in their genetic material. In the hospital environment however they suffer continuous exposition to antibiotics. Many of them die by the antibiotic action but carriers of mutations that provide resistance to those antibiotics proliferate freely. These resistant microorganisms when submitted to other antibiotics again undergo natural selection and those which became resistant to these other drugs are preserved and proliferate. Thus strains of multiresistant (nontreatable) mutant bacteria emerge in hospitals.

The use of antibiotics is a factor that promotes natural selection and the emergence of multiresistant bacteria. This is the reason why hospitals often have committees that control the use of antibiotics.

Answer 2

The multi resistance to antibiotics conquered by the mycobacteria can be well explained by the synthetic theory of evolution. According to this theory the bacteria undergo certain genetic changes through acquiring mutations over generations to conquer the drug resistance. The genetic drift that is alteration in the structure of the gene causes drug resistance in the same gene that was earlier susceptible to the antibiotic. By acquiring the mutation in the gene and under going confirmational changes in the gene product through the course of evolution the organisms gain multiple resistance to antibiotics.