Bacteriophage Therapy: The Enemy of My Enemy is My Friend
Since the original discovery of antibiotics, a medicine inhibiting the growth of or destroying microorganisms, many classes of antibiotics have been discovered and are widely used for treating infected patients, preventing wound infection, and expediting the growth of livestock. The use of antibiotics has saved innumerable lives. However, the emergence of antibiotic resistant bacteria is now a growing concern.
Abusive use of antibiotics for the last 20 years has given a selection pressure to pathogenic bacteria so only bacteria that have resistance or develop antibiotic resistance survive through the antibiotic treatment, and they expand their population at the infection site or growing niche. The abuse of antibiotics, such as taking antibiotics when you have a cold, which is not a bacterial infection, increases the chance of the development of antibiotic resistance in human patients. This drug resistance spreads through the food cycle and health care cycle all over the world.
Furthermore, bacteria can transfer the drug resistant genes to other pathogenic or non-pathogenic bacteria. For example, if one type of bacteria survives through antibiotic treatment in your stomach, all of your commensal bacteria are potentially able to get the drug resistant genes, which contributes to worldwide emergence of multidrug resistant bacteria, or so called super-bacteria. Patients infected with this drug resistant super-bacteria can’t be treated with common antibiotics. At least two million cases of infectious diseases are caused by antibiotic resistant bacteria and about twenty-three thousand people per year die from this infection.
Pathogens resistant to certain classes of antibiotics need to be treated with other classes of antibiotics. However, we are living a post-antibiotic era and the classes of antibiotics are limited. We have rarely discovered new classes of antibiotics since 1987. Although there has been much research to design synthetic antibiotics, it hasn’t been enough to catch up with the emergence of drug resistance.
One alternative therapeutic approach for drug resistant bacteria is to specifically target pathogens by utilizing their enemy – bacteriophage. The term bacteriophage is derived from “bacteria” and the ancient Greek, “to devour”. Bacteriophage is a small virus that only kills its target bacteria but does not affect other bacteria and eukaryotic cells like human cells.
Researchers have discovered over six thousand phages so far as they are the most abundant and ubiquitous organisms on earth.
Phage therapy is described as the therapeutic use of phages to treat pathogenic bacterial infection. This therapy has many benefits over antibiotic treatment, including being effective against multidrug resistant bacteria, targeting specific bacteria, being relatively low cost and harmless to humans.
This therapy also possesses a synergetic effect with antibiotics. Phage therapy not only eliminates multidrug resistant bacteria but also prevents the emergence of resistance because it specifically prevents the growth of target pathogens.
This method is still being tested for many bacterial infections but the advantage gained from using it is promising. In Georgia, about thirty thousand children were treated with oral phage prophylaxis to prevent bacterial dysentery. The children were followed for over 100 days and showed three to eight-fold decreases in the incidence of dysentery. Despite its outstanding benefits, phage therapy has not been approved in countries other than Georgia.
We need to rethink how we utilize antibiotics, which are a “limited resource”. They are a natural resource like a fuel. If we abuse antibiotics and use up the resource, we don’t have many alternatives. In terms of alternatives, phage therapy is a human friendly method to replace or supplement antibiotics. Some people have a misunderstanding that phage is a virus that can be harmful to humans, however, in actuality it only attacks bacteria. We need to build a new friendly relationship with bacteriophage, the enemy of our enemy.