Microbes start and win
Scientist: "complete rejection of antibiotics will not destroy super-bacteria"
Mikhail Gelfand, Deputy director of the Institute of Information Transmission Problems of the Russian Academy of Sciences and a professor at Skoltech, spoke about why humanity is losing the "arms race" with bacteria, how it is possible to grow a super microbe in just 11 days and why a complete rejection of antibiotics for a while will not destroy all "super-bacteria".
Last weekend, the country's leading scientists and science popularizers took part in the "All–Russian Laboratory" - an action to popularize science, in which everyone could take part. People who became "laboratory assistants" in such a laboratory could test their knowledge and listen to lectures by "zavlabs" about various topical problems of science.
The head of such a laboratory at the Institute of Information Transmission Problems of the Russian Academy of Sciences in Moscow was Mikhail Gelfand, a well–known Russian biologist who studies the problems of evolution. In his lecture, he told the audience about why antibiotics quickly become ineffective, and explained why the resistance of bacteria to them is not a new thing for the microbes themselves.
Chemical warfare
"One of the main problems of medicine is that bacteria quickly develop resistance to each new antibiotic. As a rule, bacteria adapt to a new type of antibiotics in 5-10 years, and after the appearance of the first microbes of this kind, natural selection is activated, and carriers of such skills quickly replace wild types of microbes," says Gelfand.
An example of this, as the scientist notes, is the history of tuberculosis in Russia – today, almost half of the strains of tuberculosis bacillus are resistant to the action of isoniazid and other popular tuberculosis treatments, and 16% of them are not affected by any of the existing antibiotics.
"We are actually returning to the situation of the late 19th century, when the heroes of the Remark, Anton Pavlovich Chekhov and other writers were treated for consumption with mountain air, koumiss and other similar things, since there was actually nothing to treat the disease," the scientist continues.
The appearance of such microbes has an extremely negative impact on the pharmaceutical industry. Drug developers, according to Gelfand, simply stop creating new antibiotics, as it becomes too expensive and useless – why spend billions on its creation if bacteria adapt to it in a few years? No new class of antibiotics has been discovered since 1987.
Bacterial "rock-paper-scissors"
"How did this situation arise and how can we deal with it? In fact, antibiotic resistance has always existed. Ian Fleming did not invent, but discovered penicillin, a substance that the fungus Penicillium secretes to fight competitors, including bacteria. And this chemical war between microbes was going on all the time," Gelfand explains the essence of the problem.
The means of attack and defense that bacteria have developed over millions of years of this "chemical war" are the reason why pathogenic microbes have developed resistance to drugs so quickly.
"As you know, the most acute struggle for existence is among their own kind, as they are fighting for the same resource. It is not the hare that runs faster than the wolf that survives, but the one that runs faster than another hare. In other words, the war is not between predators and victims, but between victims in order not to get caught by the predator first," the scientist continues.
In general, the struggle between different microbes can be imagined as a game of "rock-paper-scissors" – bacteria capable of synthesizing antibiotics kill rapidly multiplying microbes that do not have protection from them, but lose to those strains that this antibiotic does not work. And vice versa – antibiotic-resistant bacteria lose competition to their "wild" relatives, who are able to multiply faster.
Accordingly, if there were no antibiotics, then bacteria resistant to them would not exist, or would be quickly displaced by other strains. Similarly, bacteria quickly develop resistance to new antibiotics thanks to mutations, "Grandfather Darwin and the laws of evolution."
"A curious experiment was recently conducted at Harvard, during which an ordinary E. coli learned to tolerate a thousand-fold dose of an antibiotic. By allowing the bacteria to gradually adapt to tenfold increases in its concentration, in just 11 days, Harvard scientists have turned out a real "super beast" capable of living in such conditions," says Gelfand.
Supermicrobial Factories
This, as the scientist explains, is the reason why doctors today force patients to drink a full course of antibiotics, even if all the symptoms of the disease have disappeared. Insufficiently prolonged treatment will only contribute to the "cultivation" of microbes resistant to the action of drugs inside the patient's body, from where they can spread further.
Thanks to this, more and more resistant types of microbes can evolve in hospitals, the driving factor for the development of which will be antibiotics that their patients take in insufficiently high doses. It's even worse when antibiotics are added to soap and various cosmetic products.
"And the worst thing is the use of antibiotics in animal husbandry and poultry farming. Until recently, cattle and poultry were fed small doses of antibiotics, and indeed, they grew a little better. But poultry farms and large farms are the place where soil bacteria meet with our pathogens," the biologist continues.
As Gelfand notes, pathogenic microbes, as a rule, live inside the human body or other animals and rarely encounter antibiotics. Their "cousins" from the soil, on the contrary, constantly fight with each other with the help of "chemical weapons" and have genes of resistance to their action. And their simultaneous exposure to an environment rich in antibiotics leads to predictable consequences.
"For example, enterococci resistant to the action of vancomycin are almost certainly a "product" of animal husbandry. Fortunately, triclosan soap was banned last year as antibiotics in animal husbandry in the United States from the first of January this year. In fact, there was a terrible situation in the USA – 80% of antibiotics were used to treat livestock, and most of them were used in real medicine. All this was a colossal waste of intellectual potential," concludes Gelfand.
– Mikhail Sergeyevich, is it possible to predict in which direction the evolution of bacteria will go, and to create antibiotics "in reserve"?
– In the most general form, such studies can be carried out, but if you study each specific case, then probably not. At one time, there was a theory that antibiotics should be of a narrow spectrum in order to slow down the pace of adaptation of bacteria to them, since the "antidote" will look for one, not several microbes.
Pharmaceutical companies did not go for this for two reasons – there are sharp requirements for the quality of diagnostics, which was difficult to do until recently. In addition, the development costs will be the same as for broad-spectrum antibiotics, and the market will be very small. Therefore, no one really tried to go this way, neither private owners nor the state. The state could help here by setting rules for the use of antibiotics, which in principle is already being done.
– If the fight between antibiotics and bacteria continues, what will win – will the "superbugs" survive or will they be destroyed by the "cargo" of their devices to fight drugs?
– I think that bacteria will win in any case simply due to the fact that there are a lot of them and they are very diverse. There are examples of when humanity has defeated diseases, but in all these cases it was not drugs that defeated them, but vaccines. Vaccines work well against viruses, which are relatively simple, and against bacteria, to put it mildly, they are not insanely effective. They reduce the likelihood of getting sick, facilitate the course of the disease, but do not guarantee protection.
In addition, many viruses work against specific animal species, and bacteria can live in different representatives of the living world. Therefore, I think that bacteria will always be with us. Even if you create a super-antibiotic that kills absolutely all microbes, it will kill not only pathogens, but intestinal flora, without which we cannot live.
– Won't this situation make people more inclined to believe in homeopathy and other "alternative" methods of treatment?
– Those people who believe in homeopathy, as a rule, do not worry about how quickly antibiotics lose their effectiveness. Homeopaths themselves behave cautiously and stipulate that they do not treat serious infectious diseases. Then, of course, there may be a situation where no medications will help, and some people may begin to believe in miracles and similar drugs.
– Back in the days of the Soviet Union, our scientists considered bacteriophage viruses as a possible replacement for antibiotics, will they be able to replace them?
– Bacteriophages and microbes live with each other much longer than we do, and none of them has won yet. The first adapted to attack bacteria, and microbes – to defend themselves from them. In essence, it will be the same as with antibiotics. Highly specific bacteriophages will allow treating specific diseases, and universal viruses will quickly lose their resistance and will be dangerous for the intestinal microflora. There are doubts that such therapy will work especially effectively.
– Is it possible to temporarily abandon antibiotics, restore populations of wild types of microbes and "reset" the current situation?
– There is no feeling that they recover when they refuse antibiotics. It looks like this road is one-way. At first, yes, the viability of microbes deteriorates, but over time additional mutations appear that compensate for some of the losses. The bacterium does not return to its original state, but becomes more adapted while maintaining resistance to the antibiotic. It seems to me that this process works faster than returning to wild types of microbes, and this is one of the possible explanations for what we are facing now.
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26.04.2017