Bacteriophages or simply phages, are viruses that infect bacteria. Phage therapy , as the name suggests strives to utilize these phages as antimicrobials. Frederick Twort (1915) and Felix d'Herelle (1917) independently discovered the bacteriophages. Seeing the potential of phages to be used as a treatment tool against bacterial infections, Herelle started his experiments. He got his first success when he used phages to cure dysentry in 1919. Thereafter, different phage formulations against different diseases emerged in the market. But this hype was shortlived. With the advent of antibiotics, the phage cocktails were relegated to a backseat. Now, with the emergence of antibiotic resistant strains, phage therapy is again being looked into as a potential treatment tool against pathogenic bacteria.
Phages maybe effective against a single strain of bacteria or multiple strains. Hence, selection of the best possible match is essential. It has been found that phages generally attach themselves to those receptors on the bacterial surface which are responsible for the virulence of the bacteria. Hence, if the bacteria mutates itself so that the phage no longer attaches to it, there is an increased probability that the mutation would be in the receptors. However, even if the bacteria does acquire resistance to a phage, the phages themselves can mutate back effectively nullifying the acquired resistance of the bacteria. To prevent the rapid acquirement of resistance by the bacteria against phages, it has been proposed that a mixture of phages instead of one single type of phage be used.
The problem with phage therapy is that not much is known about the behavior of phages inside an eukaryotic organism. This requires a long and detailed experimentation. Although it is believed that the phages wouldnt directly affect the eukaryotic cells, there can be no surety of how they will behave with the beneficial bacterial flora already present within the human body. Another problem with phages is that they are rapidly eliminated from the body. So either longer circulating phage variants need to be selected or they must be shielded from the immune system of the body. Also, the bacterial flora of each individual may differ and thus it remains to be seen whether a standardized concoction of phages can be used for all people. Apart from this, there remain the usual problems of production and delivery of phages.
Phage therapy had been used extensively in some parts of the world like the former USSR. Pyophage and Intestinophage are two phage preparations widely available in the Republic of Georgia. Pyophage is a cocktail against pus producing bacteria while the other one is used against diarrhoea and gastrointestinal upsets.
References
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3586887/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3400130/
Phages maybe effective against a single strain of bacteria or multiple strains. Hence, selection of the best possible match is essential. It has been found that phages generally attach themselves to those receptors on the bacterial surface which are responsible for the virulence of the bacteria. Hence, if the bacteria mutates itself so that the phage no longer attaches to it, there is an increased probability that the mutation would be in the receptors. However, even if the bacteria does acquire resistance to a phage, the phages themselves can mutate back effectively nullifying the acquired resistance of the bacteria. To prevent the rapid acquirement of resistance by the bacteria against phages, it has been proposed that a mixture of phages instead of one single type of phage be used.
The problem with phage therapy is that not much is known about the behavior of phages inside an eukaryotic organism. This requires a long and detailed experimentation. Although it is believed that the phages wouldnt directly affect the eukaryotic cells, there can be no surety of how they will behave with the beneficial bacterial flora already present within the human body. Another problem with phages is that they are rapidly eliminated from the body. So either longer circulating phage variants need to be selected or they must be shielded from the immune system of the body. Also, the bacterial flora of each individual may differ and thus it remains to be seen whether a standardized concoction of phages can be used for all people. Apart from this, there remain the usual problems of production and delivery of phages.
Phage therapy had been used extensively in some parts of the world like the former USSR. Pyophage and Intestinophage are two phage preparations widely available in the Republic of Georgia. Pyophage is a cocktail against pus producing bacteria while the other one is used against diarrhoea and gastrointestinal upsets.
References
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3586887/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3400130/
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