What are bacteriophages used for in medicine? What are bacteriophages and what are they used for?

CM. ZAKHARENKO, Candidate of Medical Sciences, Associate Professor, Military medical Academy them. CM. Kirov, St. Petersburg

Bacteriophages are unique microorganisms, on the basis of which a special group of therapeutic and prophylactic preparations has been created in terms of their properties and characteristics. Their underlying actions are natural physiological mechanisms interactions between phages and bacteria make it possible to predict the infinite diversity of both bacteriophages themselves and possible ways their applications. As bacteriophage collections expand, new target pathogens will undoubtedly appear, and the range of diseases in which phages can be used both as monotherapy and as part of complex treatment regimens will expand.

Thus, the use of the polyvalent pyobacteriophage Sextaphage in the treatment of infected pancreatic necrosis (Perm State Medical Academy named after Academician E.A. Wagner) made it possible to quickly restore the main parameters of homeostasis and the functions of organs and systems in patients. There has also been a significant decrease in the number postoperative complications And deaths: in the group of patients treated with standard therapy, mortality was 100%, while in the troupe treated with BF - 16.6%.

Due to the harmlessness and reactogenicity of BP preparations, it is possible to use them in pediatric practice, including in newborns. The experience of the Nizhny Novgorod Regional Children's clinical hospital, where, during the period of complication of the epidemiological situation, along with the usual anti-epidemic measures, BP - Intesti-bacteriophage and BP Pseucfomonas aeruginosa were used. An 11-fold decrease in the incidence of nosocomial infection of Pseudomonas aeruginosa etiology showed high efficiency BF applications. BF preparations can be prescribed both for the treatment of dysbacteriosis and disorders digestive system and to prevent mucosal colonization gastrointestinal tract opportunistic bacteria. Multicomponent preparations of BF are ideal for immediate relief of the first signs of gastrointestinal upset.

To date, the company is planning whole line priority areas for the development and production of therapeutic and prophylactic bacteriophages, which correlate with the newly emerging global trends. New preparations are being created and introduced: BF against serrations and enterobacteria have been developed, work is underway to create a phage preparation against Helicobacter pylori.

Only one manufacturer of these drugs is NPO Microgen, according to the report of the deputy head of the department of science and innovative development Alla Lobastova, produces more than 2 million packages annually. Unfortunately, the ideas of many doctors about bacteriophages are far from being objective. Not many people know that bacteriophages active against the same pathogen can belong to different families, have different life cycles, etc. For example, P. aeruginosa bacteriophages belong to the families Myoviridae, Podoviridae, Siphoviridae, life cycle or moderate. Different strains of the same pathogen may have different susceptibility to bacteriophages. Most experts know (heard, someone used) about the existence of liquid and tablet dosage form therapeutic and prophylactic preparations of bacteriophages. However, their range is much wider, which can be attributed to the unconditional advantages, especially in combination with a variety of routes of administration (oral administration, enemas, applications, irrigation of wounds and mucous membranes, introduction into wound cavities, etc.). TO obvious benefits bacteriophages traditionally include a specific effect on a rather limited population of bacteria, a limited existence (until the target population of microorganisms disappears), the absence of side effects such as toxic and allergic reactions, dysbiotic reactions, etc. These drugs can be used in a variety of ways. age groups and during pregnancy. Bacteriophages themselves are not significant allergens. Cases of intolerance to bacteriophage preparations are mostly associated with a reaction to the components growth medium. All major manufacturers of this group of drugs strive for the maximum quality of the components used, which reduces the likelihood of such reactions. In the context of growing antibiotic resistance, some authors suggest considering bacteriophages as the best alternative to antibiotics. Therapeutic and prophylactic preparations of bacteriophages are a cocktail of specially selected combinations (a complex of polyclonal highly virulent bacterial viruses, specially selected against the most common groups of pathogens of bacterial infections) based on the manufacturer's phage collections. Branches of FSUE "NPO Microgen" in Ufa, Perm and Nizhny Novgorod - modern centers production of such drugs. The possibility of creating therapeutic and prophylactic preparations of bacteriophages adapted to specific pathogenic microorganisms is another major advantage of this group of preparations. The growth of bacterial resistance to antimicrobial drugs and the frequent polyetiology of modern infectious diseases require combination antibiotic therapy (two, three, and sometimes more antimicrobials). For selection efficient scheme therapy with antibiotics, in addition to the actual sensitivity of the bacteria to the drug, it is necessary to take into account enough big number factors. Phage therapy also has certain advantages in this regard. On the one hand, the use of a combination of bacteriophages is not accompanied by their interaction with each other and does not lead to a change in the schemes of their application. Within the existing set of therapeutic bacteriophages, there are a number of well-proven combinations - bacteriophage coliproteus, pyobacteriophage polyvalent, intesti-bacteriophage. On the other hand, bacteria do not common mechanisms resistance to antibiotics and phages, therefore, they can be used both when the pathogen is resistant to one of the drugs, and in the combination of "antibiotic + bacteriophage". This combination is especially effective for destroying microbial biofilms. The experiment convincingly shows that combined application iron antagonists and bacteriophage can disrupt the formation of biofilms Klebsiella pneumoniae. At the same time, both a significant decrease in the number of microbial populations and a decrease in the number of "young" cells are noted. One more important feature action of bacteriophages is such a phenomenon as the induction of apoptosis. Some strains of E. coli have genes that cause cell death after the introduction of the T4 bacteriophage into it. Thus, in response to the expression of the late genes of the T4 phage, the lit gene (encodes a protease that destroys the EF-Tu elongation factor necessary for protein synthesis) blocks the synthesis of all cellular proteins. The prrC gene encodes a nuclease that cleaves lysine tRNA. The nuclease is activated by the product of the T4 phage stp gene. In T4 phage-infected cells, rex genes (belonging to the phage genome and expressed in lysogenic cells) cause the formation of ion channels, leading to the loss of vital ions by the cells and subsequently to death. The T4 phage itself can prevent cell death by closing the channels with its proteins, products of the rII genes. In the case of the formation of bacterial resistance to an antibiotic, one has to look for new options for modifying the active molecule or fundamentally new substances. Unfortunately for last years the pace of introduction of new antibiotics has slowed significantly. The situation with bacteriophages is fundamentally different. The collections of major manufacturers include dozens of ready-made bacteriophage strains and are constantly replenished with new active phages. Thanks to constant monitoring of the sensitivity of isolated pathogens to bacteriophages, manufacturers adjust the phage compositions supplied to the regions. Thanks to adapted bacteriophages, it is possible to eliminate outbreaks of nosocomial infections caused by antibiotic-resistant strains.

At oral intake bacteriophages quickly reach the foci of infection localization: when taken orally by patients with purulent-inflammatory diseases, after an hour, phages enter the bloodstream, after 1–1.5 hours they are detected from bronchopulmonary exudate and from the surface of burn wounds, after 2 hours - from urine, and also from the cerebrospinal fluid of patients with traumatic brain injury.

Thus, bacteriophages are unique microorganisms, on the basis of which a special group of therapeutic and prophylactic preparations has been created in terms of their properties and characteristics. The natural physiological mechanisms of interaction between phages and bacteria underlying their action make it possible to predict an infinite variety of both bacteriophages themselves and possible ways of using them. As bacteriophage collections expand, new target pathogens will undoubtedly appear, and the range of diseases in which phages can be used both as monotherapy and as part of complex treatment regimens will expand. A modern view of the future fate of phage therapy should be based both on the high specificity of their action and on the need to strictly observe all the rules of phage therapy. Contrasting bacteriophages with any means of etiotropic therapy is erroneous.

Gaining more and more fans among doctors, pushing antibiotics into the background. Once upon a time, the advent of antibiotics completely changed the way doctors think about treatment. Previously hopeless patients began to recover, treatment algorithms were extremely simplified, mortality fell sharply ... Miracles! Magic Medicines! But the enthusiastic attitude did not last long. Too many problems started to arise.

The enemy of my enemy is my friend

Now the "slippery" issues of antibiotic therapy are known to everyone. The action of antibiotics is accompanied by:

Destruction of the necessary, "useful", intestinal microflora and mucous membranes;

Active growth of new strains of bacteria resistant to them;

The occurrence of side effects due to the systemic action of drugs.

In this regard, the search for fundamentally different drugs for the treatment of bacterial infections has become relevant. And then bacteriophages came to the fore.

Bacteriophages are viruses that selectively infect bacterial cells. The virus attaches to the cell wall of the bacterium and injects its genetic material into the cell. As a result, the synthesis of new viruses begins, and then the lysis of the bacterial cell occurs and the release of 200-1000 new phages that infect other bacteria. When all the bacteria of the pathogenic strain are destroyed, the bacteriophages are eliminated from the body without a trace. Many bacteriophages are highly specific, and each strain of the virus infects only a certain type of bacteria, without affecting other microorganisms and body cells. This provides a significant reduction in the number of side effects.

Thus, to the undoubted advantages use of bacteriophages can be attributed:

High safety profile, allowing them to be used in patients of any age, from newborns to very old people;

Reducing the risk of developing resistant strains of bacteria;

The possibility of their combination with any other drugs, including antibiotics.

Perhaps the only thing that limits the use of bacteriophages is their selectivity, because of which, before treatment, it is necessary to clarify the nature of the pathogen and its sensitivity to various types bacteriophages. Such an analysis is by no means carried out everywhere and takes certain time, but the improvement of diagnostic systems allows us to hope that this problem can be resolved soon.

From theory to practice

Exist different types bacteriophages: monophages, aimed at the destruction of only one type of bacteria, and polyphages, acting on several species at once pathogenic bacteria. Since bacteriophages are extremely in demand in almost all areas of medicine, from surgery and gynecology to neonatology and ENT practice, the release of bacteriophages in various forms. They are used for oral administration reg os, in the form of enemas, applications, irrigations, for introduction into the cavity of wounds, vagina, uterus, nose, sinuses, as well as for introduction into drained cavities - abdominal, pleural, Bladder, renal pelvis. The duration of the course depends on the clinical indications and can be 7-20 days. Safe, efficient and reliable bacteriophages are exactly the weapon that is so necessary in the fight against pathogenic bacteria.

Not only medicine

Progress in molecular biology and biotechnology has made it possible to use bacteriophages not only for treatment, but also for other purposes. In the United States, for example, bacteriophages are used as a safe preservative for food products. Added to foods, bacteriophages prevent the growth of unwanted bacteria.

Interesting Facts

The discovery of bacteriophages occurred in 1894, when the British bacteriologist Ernest Hankin noticed that the Indian rivers Ganges and Jumna had a significant antibacterial activity, which completely disappears after boiling. He suggested that there is some substance in the water that kills bacteria. The name "bacteriophage" ("eater of bacteria"), these viruses received in 1917 from the French scientist Felix d'Herelle, who discovered "an invisible microbe that infects the dysentery bacillus." Clarification of the nature of this "invisibility" became possible only after the advent of electron microscopy.

Achievements modern medicine and pharmaceuticals are great, but pathogens are also constantly improving and adapting to the action of those drugs that were deadly for them a couple of years ago. Where antibiotics are powerless, bacteriophages will help fight pathogenic microorganisms.

What are bacteriophages

Literally translated from ancient Greek, bacteriophages are bacteria eaters. This biological term refers to viruses that selectively infect bacterial cells.

Bacteriophages are present wherever bacteria live, so their habitat can be air, water, soil, the human body, food, clothing.

Structural features of a bacteriophage: such a virus does not have cellular structure, there is only genetic material covered with a protein coat on top. Therefore, for reproduction, they have to look for suitable cellular microorganisms.

The phage begins its destructive activity for the bacterium by injecting its own genetic information into its body, and then proceeds to active reproduction. When a bacterial cell is destroyed, from 100 to 200 new bacteriophages emerge through its fragments, immediately starting to attack nearby bacteria.

Kinds

The most famous bacteriophages:

dysenteric;
staphylococcal;
streptococcal;
potassium;
pseudomonadic;
Pseudomonas aeruginosa.

Advantages

Some scientists argue that the use of drugs based on bacteriophages will soon compete with the use of antibiotics in the treatment of various diseases.

The basis for this bold assumption is given by the following advantages of using phages:

lack of addiction and contraindications to the use of the drug;
no inhibitory effect on the immune system;
selective action (beneficial bacterial flora remains intact);
harmonious combination with other methods of treatment, including therapy with antibiotics (according to research results, phages even enhance their effect);
pronounced effect in the treatment of sluggish painful conditions caused by bacterial agents insensitive to antibiotics.

This allows the bacteriophage to be successfully used for children, the elderly, pregnant women, debilitated patients.

Indications

Indications for the inclusion of bacteriophages in the treatment regimen are the following infections:

surgical (abscess, felon, paraproctitis, osteomyelitis, boils, burns, phlegmon, carbuncles, purulent wounds);
urogenital (cystitis, pyelonephritis, colpitis, urethritis, endometritis, salpingo-oophoritis);
enteral (cholecystitis, gastroenterocolitis, intestinal dysbacteriosis);
blood poisoning;
diseases of ENT organs (tonsillitis, sinusitis, otitis media);
diseases respiratory tract and lungs (tracheitis, pleurisy, laryngitis, bronchitis, pneumonia).

Application methods

The method by which a bacteriophage should be applied directly depends on the nature and location of the focus of inflammation. IN different situations The following uses would be appropriate:

orally (the drug is taken by mouth);
rectally (enema bacteriophage);
locally (in the form of washing, lotions, irrigation, instillation, rinsing, the introduction of turundas soaked in the drug).

The bacteriophage works more effectively if the treatment combines different ways applications. There are certain clinical indications, according to which the bacteriophage is taken orally in tablets, and local action renders bacteriophage liquid in the form of a lotion.

Bacteriophage-based drugs are gaining popularity in the form of solutions, aerosols, tablets, suppositories and gels. Pharmacy forms drugs are supplied detailed instruction how to take bacteriophage.

Contraindications

Most people with a certain degree of mistrust consider the possibility of treatment with bacteriophages, although the effectiveness and, most importantly, the safety of such therapy has already been proven.

the only possible contraindication May be hypersensitivity to bacteriophages, although cases allergic reaction on bacteriophages are not typical.

Bacteriophage preparations

The pharmaceutical industry offers many drugs, the principle of action of which is based on the antimicrobial orientation of bacteriophages.

Intesti-bacteriophage (Intestifag)

Liquid immunobiological preparation antimicrobial focus. It inhibits the activity of microorganisms, disease-causing gastrointestinal tract ( bacillary dysentery, typhoid fever, enterocolitis, paratyphoid fever, dysbacteriosis, salmonellosis). It is used internally and as an enema. Contraindications: hypersensitivity to the drug. Side effects: in newborns in the first 2 days of admission, skin rashes and regurgitation are possible.
Pyobacteriophage polyvalent (Sextaphage)

It successfully copes with purulent-septic diseases of newborns and infants, purulent-inflammatory diseases of the upper respiratory tract, enteral infections. It is used to treat freshly infected wounds. There are no contraindications and side effects.
Bacteriophage of Klebsiella pneumonia (Klebsifag)

It affects bacteria that cause pneumonia, ozens, rhinoscleromas. It also helps with generalized septic conditions, for the prevention of contamination. nosocomial strains Klebsiell. There are no side effects. Contraindication: hypersensitivity to components.
Salmonella bacteriophage

Destroys cells of Salmonella and microorganisms similar to them in antigenic structure. Suitable for the treatment of salmonellosis in children and adults. There are no contraindications and side effects.
Pseudomonas aeruginosa bacteriophage (Pseudomonas aeruginosa)

Used for treatment of injury various bodies Pseudomonas aeruginosa. Side effects not identified. Contraindication - hypersensitivity to the drug.
Streptococcal bacteriophage (Streptophage)

It kills streptococcal bacteria, which makes preparations based on it indispensable in the treatment of tonsillitis, tonsillitis, sinusitis, panaritium, festering wounds and many other ailments. For the treatment of sinusitis, it is recommended to bury this bacteriophage in the nose. There are no side effects. Contraindication: hypersensitivity to the drug.
bacteriophage coli

It has a specific antibacterial action directed exclusively against pathogenic strains coli. It is prescribed for lesions of the gastrointestinal tract, suppuration of wounds, neonatal sepsis, conjunctivitis, urogenital infections. Contraindication: hypersensitivity to the drug. No side effects have been identified.
Bacteriophage Klebsiella polyvalent

Effective in the treatment of peritonitis, pleurisy, purulent-inflammatory diseases in gynecology. It is also used in the treatment of stomatitis, periodontitis and inflammation of the sinuses. There are no side effects. Contraindication - hypersensitivity to the components of the drug.
Coliproteus bacteriophage

IN liquid form in demand for the prevention and treatment of colpitis, enterocolitis. In the form of tablets, it is more often used for advanced forms of pyelonephritis and cystitis, inflammatory processes in the pelvic organs. Contraindication: allergy to any of its components of the drug. There are no side effects.
Dysenteric bacteriophage

It is used for the treatment and prevention of dysentery. Side effects have not been identified. Contraindications: hypersensitivity to the components, and for the form of the drug in tablets - the patient's age is less than 1 year, the period of pregnancy and lactation.

Do not exaggerate the danger of the viruses that make up similar drugs and bacteriophage analogues. They are deadly only for bacteria, disease-causing. If the doctor considers it appropriate to include bacteriophages in the treatment regimen, you should trust and tune in to a speedy recovery.

The use of bacteriophages is carried out exclusively for the intended purpose and under the supervision of the attending physician.

bacteriophages in medical practice used in the diagnosis, treatment and prevention of infectious diseases.

A. In diagnostics, bacteriophage is used in the implementation of the cultural method of research to determine the type of isolated pure culture, as well as for its typing. The following method of using a bacteriophage to indicate the presence in the pathological material a certain kind bacteria without isolating it in pure culture is not widely used.

1. The phage titer increase reaction is based on the ability of a specific bacteriophage to replicate only in bacterial cells of its “own” species. It is carried out according to the following principle. A certain amount of a specific bacteriophage is added to the pathological material, it is incubated in a thermostat, and then the amount of phage is again determined. If it increased, it means that the bacteriophage "found" cells of its "own" species for replication, therefore, bacteria of the desired species are present in the pathological material.

2. In the process of identifying a pure culture, species and type bacteriophages are used.
A. Species bacteriophages are used for phage indication. Dedicated pure culture inoculate with a lawn on plate agar and drop a drop of the species bacteriophage onto it. If the culture belongs to the desired species, then there will be no growth at the place of application of the drop, otherwise, phage will be observed at the place of application of the drop. bacterial growth. Sometimes, after the bacteriophage has been applied, the agar plate petri dish is tilted, allowing the drop to flow down the rim of the dish (which is why this method is called "dribble drop").

b. Typical bacteriophages are used for phage typing. The principle of the method is as follows.
1. The strain to be typed is seeded with a lawn on plate agar.
2. Then, drops of typical bacteriophages are dropped onto the seeded surface (each in its own square, marked in advance, for example, with a glassgraph at the bottom of a Petri dish).
3. The inoculation dish is incubated in a thermostat.
4. Experience is taken into account by registering "sterile spots" or "plaques" - places of lack of growth at the site of application of a bacteriophage drop, to which it is sensitive this option bacteria.
5. Fagovar (phagotype) is designated by listing typical phages that lyse this variant.
B. The use of bacteriophages (usually species) for treatment is referred to as phage therapy. For the purpose of treatment, bacteriophages are applied topically (in the form of irrigation of the affected surface, injection into a local focus pathological process etc.), since their parenteral administration leads to the development of an immune response to a foreign phage protein. If a therapeutic bacteriophage is used orally (to treat intestinal infections), then it is best to use a tablet form of the drug, coated with an acid-resistant shell that dissolves in the alkaline environment of the intestine - bacteriophages are very sensitive to low pH and are quickly inactivated in the acidic environment of the stomach.
B. Phage prophylaxis - the use of a bacteriophage (also, as a rule, a species phage) to prevent the development bacterial infection. Currently used for emergency prevention typhoid fever and dysentery (under emergency prevention is understood as a set of measures to prevent the development of the disease after the act of infection has taken place, i.e. entry of the pathogen into the body of the patient).

1. In medicine:

One area of application for bacteriophages is antibiotic therapy alternative to taking antibiotics. For example, bacteriophages are used: streptococcal, staphylococcal, klebsiella, polyvalent dysentery, pyobacteriophage, coli, proteus and coliproteus and others.

Bacteriophages are also used in genetic engineering as vectors that transfer DNA segments, it is also possible natural transmission genes between bacteria through some phages (transduction).

2. In biology

Bacteriophages M13, phage T4, T7 and phage l are used to study protein-protein, protein-peptide and DNA-protein interactions by phage display.

Since bacteriophage reproduction is possible only in living cells, bacteriophages can be used to determine the viability of bacteria. This direction has great prospects, since one of the main issues in various biotechnological processes is the determination of the viability of the cultures used.

ADVANTAGES OF BACTERIOPHAGES OVER ANTIBIOTICS:

highly efficient biological preparations antibacterial action for the prevention and treatment of acute intestinal infections and purulent-inflammatory diseases, the treatment of dysbacteriosis;
when applied do not violate normal biocenosis a person (unlike antibiotics, after which it is always necessary to treat dysbacteriosis - Author's note);
Indispensable in the resistance of pathogens to antibiotics;
Can be applied in complex therapy with others medicines;
necessary in the treatment of dysbacteriosis in combination with drugs that normalize the intestinal microflora;
Recommended for adults and children
· Manufactured using natural raw materials.

To the benefits bacteriophage preparations include a narrow specificity of action, which, unlike antibiotics, does not cause inhibition of normal microflora. Proven stimulant effect staphylococcal bacteriophage on bifidobacteria - essential component intestinal microbiocenosis. The use of bacteriophages for the treatment of infectious diseases stimulates the factors of specific and non-specific immunity, which is especially effective for the treatment of chronic inflammatory diseases against the background of immunosuppressive conditions, bacteriocarrier.

Both antibiotics and bacteriophages act directly on microbes, only antibiotics destroy not only pathogenic, but also normal microflora, breaking natural balance, while bacteriophages act only on pathogenic microorganisms. When a phage encounters a sensitive microbial cell, it penetrates inside it, switches its mechanism of action to reproduce its own kind, which, breaking the cell membrane, attack other microbes tenfold. Lysis becomes spontaneous, and the release of unwanted microbes occurs in a matter of hours. It should also be mentioned complex preparations, which are a set of phages to several pathogens at once: this is a pyobacteriophage for the treatment purulent-septic diseases and intestibacteriophage against intestinal infections.

The main manufacturers of bacteriophages in our country are NPO "Immunopreparat" (Ufa), an enterprise for the production of bacterial preparations ( Nizhny Novgorod), MP "Biofon" (Saratov), NPO "Biomed" (Perm).

Clinical practice has shown the effectiveness of the use of bacteriophages in infectious diseases of the gastrointestinal tract, as well as in inflammatory diseases sinuses, oral cavity, upper respiratory tract, genitourinary system, cholecystitis, etc., caused by bacteria sensitive to the phage. However, phages, these "natural orderlies", can be used not only for treatment, but also for the prevention of infectious diseases. They are non-toxic, have no contraindications for use, can be used in combination with any other medicines. They can be prescribed to pregnant women, nursing mothers and children of any age, including premature babies.

The main condition for their successful application is to test the isolated culture for sensitivity to the corresponding phage. Featured amazing pattern: unlike antibiotics, the sensitivity of clinical strains of microorganisms to bacteriophages is stable and tends to increase, which can be explained by enrichment medical preparations new races of phages.

Bacteriophage preparations are prescribed orally for diseases internal organs or locally, directly on the lesion. The action of the phage is manifested already 2-4 hours after its introduction (which is especially important in intensive care). Bacteriophages penetrate the blood, lymph and are excreted through the kidneys, sanitizing urinary tract. In the 1920s, phages were actively used in the treatment of various diseases.