Mutation: resistance of viruses and microbes

• April 26, 2024

In a world in which epidemics have crossed borders, one can think that the battle is lost. However, this situation becomes a new challenge for specialists. Antonio Lazcano, researcher of the Faculty of Sciences of the UNAM, He explained that when bacteria and viruses have a special resistance to antibiotics, we talk about a case of "microbial evolution".

To explain this phenomenon, the researcher uses the theory of the evolution of Charles Darwin which contains the basic concept of "natural selection".

"Let's suppose that I have a bacterium and I observe that it begins to divide by bipartition and multiply. It may be that one of the new bacteria has the ability to break down an antibiotic, but if it never comes into contact with the product, it does not constitute what we call a selection pressure. Maybe that bacteria disappears with time.

"On the other hand, if we expose said bacterium to the antibiotic, evidently that which is not resistant will perish, and what will happen is that the population that by causality is resistant will now have the ability to multiply without difficulty."

Then, he added, before a specific selection pressure, the populations will respond, they will evolve in a certain way. This process is called "natural selection".

For this to happen, hundreds of millions of years are not required, since pathogens are known to be capable of becoming resistant in a few months. Examples of this are influenza viruses and HIV / AIDS, he said.

"Everything that replicates in the biosphere depends on nucleic acids: DNA and RNA, two molecules that store genetic information. But an RNA molecule evolves, mutates, a million times faster than a DNA molecule. If we do not have an HIV vaccine yet, it is because RNA gives us the ability to change, to evolve with enormous speed. "

The specialist explained that of every 10 people who have just contracted HIV, about 10 percent is being infected by strains resistant to antiretrovirals, therapy that is used as a treatment.

"This means that I have AIDS viruses that are multiplying; I apply antiretrovirals and as the virus never stops evolving, new resistant strains appear. A new drug can be used, but the more antiretrovirals are applied, the more resistant strains will emerge, "he said.

However, to combat the biological diversity of HIV / AIDS, there is a solution and it is feasible. This consists of promoting the use of uncontaminated blood, sterile needles, the practice of condom use and safe sex. "These measures do not impose selection pressures on the virus that favor the formation of resistant strains."

The virus will never generate resistance to the condom, which is a physical barrier, nor to safe sex practices. So with the use of the condom, the individual is not only protecting himself, but at the same time, is preventing the appearance of new strains of the virus, he said.

Video Medicine: The Evolution of Bacteria on a “Mega-Plate” Petri Dish (Kishony Lab) (April 2024).