Tuesday, December 28, 2010

Phage Therapy

Bacteriophage therapy is a method of treating bacterial infections, and a newly developing alternative to antibiotics. In several European countries, phage are being used regularly for this purpose. They are used to treat tropical infections, such as nasal abscesses. At times, they have been proven effective at preventing the amputation of infected limbs in people who have an antibiotic resistant infection. Despite their obvious advantage over antibiotics, their use has been limited by the Food and Drug Administration. The topic continues to be controversial

Phage therapy has several benefits over other methods of treating bacterial infections:
  1. The observance of bacterial resistance to antibiotics is significantly higher to than resistance to phages. However, when mutant bacteria do gain immunity to phage particles, this can be overcome by treating the infection with a phage "cocktail", a careful mixture of different kinds of phages. The presence of a variety of phages (that target variety of surface receptors on bacterial cell walls) significantly reduces the survival chances of even mutant bacteria.
  2. Bacteriophage have a very narrow host range, meaning they will not infect bacteria they are not targeted to infect. This specificity is an advantage when it comes to treating bacterial infections inside organisms. For example, our bodies contains symbiotic bacteria that are necessary for our survival. Since antibiotics can destroy a wide range of bacterial species, they can cause various side effects that are virtual absent in when using phage therapy.
  3. Usage of phage therapy also eliminates other problems that come with the use of antibiotics, such as the misuse or overdose of medication. Since phage naturally multiply between lysis of bacterial cells, their repeated usage is usually unnecessary. In the case of antibiotics, repeated prescription is very important to continuously treat the infection, a characteristic that also significantly raise costs of treatment.
  4. While it is often quite expensive and time consuming to create new antibiotics, as well as study its potential side effects, it is relatively inexpensive and quick to develop a phage therapy for a certain bacterial infection. Being the most abundant and diverse organisms on the planet, it is possible to isolate a novel phage from any given environmental sample. However, it is important to know the exact species of bacteria being treated, because, as mentioned before, phages have a very specific host range.
Further reading:
http://www.popsci.com/scitech/article/2009-03/next-phage
http://www.pharmas.co.uk/blog/bacteriophage-treatments

Monday, December 27, 2010

Introduction to Phage

Mycobacteriophage are viruses that specifically infect mycobacteria, a genus of bacteria that includes pathogens known to cause serious diseases, such as tuberculosis. They do this by attaching to specific receptors on bacterial cell walls, and injecting their genetic material. Some of these phages can integrate their genomes into the host genome, while others cannot (mainly due to differences in genetic composition). Once the genome has been injected into the bacterial host, it takes control of the bacterial cell's machinery, including ribosomes and proteins, in order to produce new phage progeny. The accumulation of viral particles along with endotoxins results in the lysis, or bursting, of the host bacterium. These phage particles then find new hosts in their surroundings, and repeat this parasitic cycle.
Despite their simple appearance, bacteriophage are the most numerous and diverse entities on the planet. Since their identification and isolation in the early 1900s, these remarkable organism have contributed to our knowledge of mycobacterium and led towards the development of effective therapeutic tools for mycobacterial diseases. Their ability to infect and kill bacteria is being applied towards the development of inexpensive and rapid therapeutic and diagnostic tools, such as the diagnosis of pulmonary tuberculosis in humans, an infection caused by Mycobacterium tuberculosis.


Welcome!

Welcome to our blog: Discover Phage! This blog is dedicated to sharing our love for phage with you, the reader! Our previous semester at Virginia Commonwealth University involved isolating and purifying novel Mycobacteriophages from environmental soil samples. This coming semester, we will be annotating genomes of several phages from our class.

We will be posting weekly on various topics, such as phage therapy, research, phage genomics, and other phage-related things.

This is Raiha’s phage: http://phagesdb.org/phages/Orby/
This is Rachel’s phage: http://phagesdb.org/phages/Wally/
Check out all the VCU phages here: http://phagesdb.org/institutions/VACU/