Research, Technology

What is phage therapy and can it replace antibiotics?

One of the most important steps in the developmentmodern medicine was the discovery of antibiotics. Many diseases that were previously considered fatal, from that moment began to be easily treatable. This allowed to increase the average life expectancy by 23 years. But, unfortunately, a little less than 100 years after the discovery of penicillin, humanity is in danger of returning to a time when antibiotics did not exist. The drugs themselves, of course, will not disappear anywhere, but they will be completely ineffective, as the bacteria become resistant to them. The solution could be a new class of antibiotics, but they haven't been around since the 1980s. According to some scientists, the only correct solution in this situation is the development of drugs that can replace antibiotics. In fact, such drugs exist and are even already used in medicine.

Bacteriophages are viruses that can infect bacteria

Content

  • 1 Why antibiotics become ineffective
  • 2 What is phage therapy
  • 3 Advantages and disadvantages of phage therapy
  • 4 Where scientists find bacteriophages
  • 5 Perspectives on phage therapy

Why antibiotics become ineffective

Antibiotics have become the cornerstone of modernmedicine. On the one hand, they allowed to solve many problems. However, along with them, pathogenic bacteria began to appear that are capable of evading antibiotics. This phenomenon is called antimicrobial resistance, or AMR.

The World Health Organization callsAMR is one of the most serious threats to human health. Scientists estimate that drug-resistant bacteria were responsible for more than a million deaths in 2019. That is, antibiotic resistance has become one of the main causes of death in the world.

Superbugs kill more people every year than AIDS and malaria

But ever-decreasing efficiencyantibiotics is not the only downside. Many studies show that they cause various health problems. In particular, because of them, people become allergic. Sometimes antibiotics even cause hallucinations or problems with thinking. To this should be added the destruction of the intestinal microflora and a number of other side effects.

Bacteria that are resistant to antibioticscalled superbugs. According to scientists, the coronavirus pandemic has provoked an even greater growth of such bacteria around the world. However, in fairness, it should be noted that superbugs existed on earth long before people began to use antibiotics in medicine, as we talked about earlier.

Phage therapy is effective even against those bacteria that cannot be destroyed by antibiotics.

What is phage therapy

Phage therapy is a method of treating bacterialinfections by viruses that infect bacteria and subsequently kill them. Such viruses are called bacteriophages. Phages infect bacteria by binding to one or more receptors on the cell surface. As a result, phage therapy is effective even in the treatment of infectious diseases against which antibiotics are powerless.

Despite the fact that phage therapy is stillnot studied, it has been used for a long time. A few years ago, we said that drugs are being created on the basis of bacteriophages. But in fact, phage therapy began to be used in medicine even earlier. For example, it became widespread in the USSR, where the study of bacteriophages began in the mid-1930s. It must be said that phage therapy is still used in the CIS countries, including Russia. Also recently, its clinical trials and even use in the US and Europe have been carried out.

Bacteriophages, unlike antibiotics, do not affect the intestinal microflora

Advantages and disadvantages of phage therapy

Phage opening is relatively fast andan inexpensive way to create drugs against infections. As experts say, unlike traditional pharmaceutical research, phage therapy, for its development, requires only basic laboratory equipment and skills. To create a new antibiotic, according to experts, it will take 10 to 15 years and at least a billion US dollars.

In fact, in order to create a drug against those orother bacteria, you just need to find a phage that can infect them. The fact is that bacteriophages are very “narrowly targeted”. On the one hand, this is their advantage. They are not capable of harming beneficial bacteria, unlike antibiotics. But, on the other hand, a certain type of microphages will have to be used to treat each disease. Antibiotics, on the other hand, are known to have a broader spectrum of action.

However, due to low cost and simplicitypreparations based on microphages, drugs may become more accessible. In particular, the developing countries of Africa, which at present often do not have access to even the simplest antibiotics, can be fully provided with drugs against bacteria.

Bacteriophages live where bacteria exist, such as in sewage

Where do scientists find bacteriophages?

The most interesting feature of bacteriophagesis that they live in the same place as the bacteria themselves, which is logical, since bacteriophages need bacteria to reproduce. For example, researchers at the Kenya Medical Research Institute have found phages capable of killing drug-resistant bacteria, Klebsiella pneumonia and Pseudomonas aeruginosa, in municipal sewage. That is, in the same place where these bacteria themselves live. The team has now identified more than 150 phages to fight various drug-resistant bacteria.

Another team of scientists from the InternationalAnimal Research Institute, also based in Kenya, has developed a phage-based technology that prevents Salmonella contamination of poultry. A team from the University of Pittsburgh was able to accumulate a bank of 10,000 bacteriophages against a wide variety of infections.

Researchers at the Kenya Medical Research Institute have already discovered more than 150 phages capable of destroying drug-resistant bacteria.

Moreover, bacteriophages are increasingly being usedfor the treatment of dangerous infections. For example, in the United States, some European countries, and Australia, phage therapy is used in emergency cases, when it is known that a person is likely to die due to drug-resistant bacteria. So a team from the University of Pittsburgh cured 40 patients with phage therapy in 2017 alone.

Perspectives of phage therapy

Although there are already successful examplestreatment of deadly diseases with phages, phage therapy is not fully understood. By their very nature, phages replicate inside bacterial cells and kill them. But it is not known how quickly this happens after the introduction of certain phages to the patient.

That is, different phages can behave differently.Therefore, it is difficult to calculate and track their dosage at different stages of the treatment of the disease. When taking antibiotics, doctors know the exact dose and time required for the drug to break down in the body. However, available data indicate that even high doses of phages are safe for humans. That is, theoretically, you can always take the maximum dose, since it will not get worse from this.

Scientists around the world need to constantly look for new phages

As mentioned above, bacteriophages are very"highly specialized". This means that you will have to constantly look for them. However, scientists are already working on studying the genome of phages. Perhaps in the future it will be possible to artificially create phages that can destroy a wider range of bacteria.

Researchers are also developing national andglobal phage banks that physicians and scientists can easily access. However, there is still no clear mechanism for the identification, procurement and mass production of phages for therapy. But most importantly, it is not yet known how long the phages will be effective, given that bacteria are able to develop resistance to them.

Bacteria quickly become resistant to phages

As scientists report, sometimes bacteria in one nightdevelop resistance to phages. Therefore, a mixture of four or five different phages is currently administered to patients to prevent resistance. But there is good news - as microphage-resistant bacteria appear, new bacteriophages appear that are able to infect and destroy them. This feature is described as a lock-and-key design.

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Given the low cost of finding new phages,scientists can constantly look for new species as bacteria develop resistance to them. Wastewater and other microbial environments are an endless source of new phages. Therefore, unlike antibiotics, nature itself will constantly create new bacteriophages capable of killing bacteria.