Bacteriophages

Phage therapy utilizes the ability of the phage to lyse the host cell. Bacteriophages attack targeted bacterium and then, after they reproduce within it, the bacteriophages release and the bacterium dies off. The released bacteriophages are attacking neighbouring bacteria, until the eradication of the whole bacterial populations. Bacteriophage perishes following the disappearance of all bacteria.

Phages are very specific, which is a major advantage over antibiotics, which counteract also the natural bacterial flora. High specificity is also the reason why the phage preparation cannot be used for any bacterial disease. The etiologic agens of bacterial infection must be known, so that it can be applied to a specific bacteriophage. It is therefore preferred to use polyvalent phage with a broader host range.

Another advantage is that the phages replicate at the site of infection, therefore upon administration of a small quantity of the phage, these particles reproduce only in a microorganism at the site of infection, in contrast to antibiotics.

There have not been described any adverse effects caused directly by phages, whereas in antibiotics the adverse effects occur relatively frequently.

The resistance to bacteriophage has not been described, and if it was discovered, the new phage strains can be isolated and therefore can overcome this resistance.

The characteristics of bacteriophages

• Highly specific particles of microorganism invading bacteria
• Replicate in the site of the infection - elimination of the originator.
• Act lytically against targeted bacteria.
• Normalize blood levels of TNFα and INF-6
• The physiological effect in the body
• Reduce antibiotic resistance
• In contrast to antibiotics, with the exception of the phage of E. coli, phages do not disrupt the intestinal flora and hence the largest natural barrier of an organism against the attack by pathogens.
• The body normally comes into contact with phages (with phages from the environment, from bacteria of the gut flora - they were also found in the saliva, urine, ...) and are gradually removed from the body the same way as other foreign proteins or metabolites.

History

In 1896, British bacteriologist Ernest Hankin observed a great antimicrobial activity in Vibrio cholerae. He did not know that they are bacteriophages and considered them as unidentifiable substance that passed through the filters and was thermolabile.

Similar phenomenon was observed two years later in Bacillus subtilis in Russia. About 20 years later, the British bacteriologist Frederik Twort hypothesized that Hankin's observations could be explained by the activity of phages.

Bacteriophages were discovered independently by Felix d'Herellem in the Institute Pasteur in Paris. The name was proposed by d'Herell, and it is based on the words "Bacteria" and "phagein" (gr.).

In any environment with bacteria's occurrence, the bacteriophages are also present, which are their natural enemies. They occur in different environments, seawater, sediments, soil, waste water, but also in the digestive tract of an animal. Total population of bacteriophages is estimated at 1,031, and are therefore the most abundant biological objects in the biosphere.