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What is Bacteriophage? How many types are there?
Bacteriophage or phage is a virus. This virus infects a bacterium and replicates within it. Bacteriophages, discovered by Frederick Twort, are one of the most diverse organisms to be present in the biosphere.
There is a difference between a virus and a bacterium. Both are microorganisms, but a virus requires a host for replication and its survival. Bacteria have these viruses within them. Phages are composed of proteins.
Their structures may be simple or elaborate. Bacteriophages have many properties like antibacterial properties due to which is finds applications in a wide number of cases.
Bacteriophages occur in the biosphere with different lifestyles, virions, and genomes. The virus in one bacterium differs from another. But there are three most important families of viruses. They are:
Myovirus: These viruses have long tails and its name “Myo” means muscles.
Siphovirus: These double stranded DNAA viruses to have long and contractile tails. They may or may not be flexible. Its shape is like a harpoon, with the aid of which it enters the bacterial cell.
Podovirus: Podoviruses have small tails and its name “Podo” means foot. These viruses use enzymes to help them degrade the walls of the bacterial cells. That way they get inside the bacteria.
What are antibiotics?
Antibiotics are a kind of antimicrobial drug which is used to treat bacterial infection. It Is also used to prevent that infection from occurring. These microorganisms either stop the bacterial growth or kill them.
But some antibiotics are ineffective against certain viruses like influenza. Penicillin was the first compound that was discovered that has antibiotic properties. It was discovered by Alexander Fleming in the year 1928.
How can bacteriophages act as an alternative to antibiotics?
Bacteriophages have many advantages. They can penetrate biofilm, unlike antibiotics, which sometimes don’t work on biofilms. This is because they cannot pass through the polysaccharide layer in the bacterial wall. But, phages have enzymes which they release and that get them through the walls. Phage therapy is the use of bacteriophages that help in the treatment of bacterial infections.
Since bacteriophages are more specific than antibiotics, they are more successful than antibiotics. They are used to treat pathogenic bacterial infections that cannot be treated by conventional antibiotics. There are many benefits of phage therapy.
One might question of resistance that the bacteria might develop due to the treatment by bacteriophage. The resistance developed against antibiotics is easier to overcome than the resistance needed to overcome antibiotics. Antibiotic resistance has occurred in cases of tuberculosis, pneumonia and dysentery.
Some research and evidence show that bacteriophages can travel to very specific sites. It can travel to the brain by crossing the blood-brain barrier as well. It has the capability to multiply when there is an appropriate bacterial host present.
It combats infections like meningitis. In the last 30 years, there has not been any new discovery of classes of antibiotics. Since phages are specific to the bacteria, before treating patients with it, a swab from the patient is taken and it is cultured before the treatment.
For treatment, phages are applied orally or topically on wounds. Injection is not usually used. It is safe for humans to use phages directly.
A deeper insight
A disadvantage of antibiotic is that its range of killing bacteria is wide so it kills the useful bacteria as well as the harmful ones.
But bacteriophage has very specific targets, so it kills only a few strains of bacteria. Therefore, antibiotics can be harmful in a way. Bacteriophages are harmless and they are useful for bacterial infection treatments.
A simple method of bacteriophage treatment is the collection of local samples of water that are high in its bacterial content and bacteriophage content.
The water sources can be water outlets, sewages, and other such effluent outlets. Another source of bacteriophage can be corpses. Then they can be applied to specific bacteria and tested.
Phage therapy has been used to treat many diseases like laryngitis, infection of the skin, dysentery, periodontitis, sinusitis, urinary tract infections, conjunctivitis, boils, burns and various other bacterial infections. They are also used to treat ulcers and infected surgical areas.
Apart from the treatment of burns and infected wounds, bacteriophages can also be used to combat nosocomial infections. The Institute of Bacteriophage, Microbiology, and Virology in Tbilisi has done that.
Since bacteriophages are self-replicating and self-implicating, they are found in abundance. It is known that about half of the world’s antibiotics are used for animals more than human medicines. Antibiotics are also used in industrial husbandries and they are sold as growth promoters.
Applications of phage therapy
The applications of phages are not limited only to the medical world and in the treatment of bacterial infection and wounds. But they can also be used as medicines for animals.
They can be used in agriculture to prevent bacterial infections like a canker. This is a step forward taken because replacing antibiotics with bacteriophages may be a great solution to developing a sustainable agriculture.
Phage therapy is an interesting field in the medical field in developing countries. According to World Health Organization, parasitic diseases and infections are responsible for the death of twenty million people every year in the developing countries.
Nearly 8 million children die of acute respiratory diseases due to bacteria like Streptococcus pneumonia. In Africa dysentery was caused by Shigella dysentery. Advanced antibiotics are not always available as they are limited.
Also, their costs are high and not everyone can afford them, especially in the developing countries. Here comes in phage therapy, which has abundant sources, it is safe to use as phages do not kill the useful bacteria as antibiotics do.
Phages have many benefits as compared to antibiotics. Phages have specific targets, so they target the bacteria that have to be killed or its growth has to be prevented. Thus, bacteriophages find more application than antibiotics and they are becoming an alternative to antibiotics.
Phage therapy is finding its applications more and more every day in the medical and agricultural field. It can be used to treat many diseases and in a more efficient way.