Bacterial viruses, also known as phages, are the most abundant biological entities on Earth and one of the keys of the control of bacterial populations. In the last decades, the relevance of phages has been increasing because of new insights about the presence of phages in many bacterial genomes, the role of phages in horizontal gene transfer, the phage-bacterium interactions as well as about defense mechanisms of bacteria against phage infection. New biotechnological applications of phages have also been proposed. The most remarkable is the use of phages as antimicrobials. Resistance of bacteria to antibiotics is continually increasing and it severely undermines the ability to control infectious diseases, being currently one of the most challenging problems in public health care. Governments counsel better control of antibiotic usage in both humans and livestock, while researchers look ahead for new generations of antibiotics that can stave off new pathogens. However, a search for alternative methods to be used as antimicrobials would be advisable. Starting 90 years ago in the former Soviet Union, therapeutics based on phages, as natural viruses that can specifically infect and kill bacteria, is now reconsidered as a possible alternative therapy. A main advantage of the use of phages as antimicrobials is that phages target specific bacterial strains, thus sparing patients from the side effects caused by destroying natural flora. For each type of bacteria known in nature, there is at least one complementary phage that specifically infects a single bacterial species. Therefore, the use of phages is possible in all bacterial infections. Another positive aspect of phages is their capacity for exponential growth. Essentially, phages closely follow the course of bacterial growth and presence, multiplying alongside bacteria, and disappearing once the bacteria is no longer present. Even though bacterial resistance is a concern, unlike antibiotics, phages can mutate in step with evolving bacteria. Finally, there is not known allergic reaction to phages, so phages are considered safe for therapeutic use. Application of phages as antimicrobial agents has been suggested in human medicine as well as dentistry, veterinary science, and agriculture. They have also been proposed to control food-borne pathogens in fresh products and during the food production chain, since phages can be applied without compromising the food's properties and shelf-life. There are still disadvantages to be considered. Because of the high specificity of phages, the disease-causing bacterium has to be identified before the administration of phages, and the appearance of resistant strains is still a problem that must be solved, probably by combining different phages. The phages selected must be only lytic, without possibilities to lysogenize and cause an uncontrolled lateral gene transfer. This implies knowing the genetic features of the phages before their application. Phages are ineffective if they cannot reach some hidden parts of a body or the interior of human cells. These facts together with the reluctant attitude of the scientific and medical community must be solved to benefit from this antimicrobial aid that could be a useful complement to antibiotics to fight bacteria.
|Title of host publication||Bacterial Infections|
|Subtitle of host publication||Characteristics, Types and Treatment|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||20|
|State||Published - Feb 1 2012|
- Escherichia coli
- Phage therapy