SEP 16, 2015

Bacteriophage Used to Kill MRSA

WRITTEN BY: Kara Marker
Methicillin-Resistant Staphylococcus Aureus (MRSA) is a dangerous bacterium that has become increasingly resistant to multiple antibiotics over time (hence its name). MRSA infections are currently treated with vancomycin, but the vicious bacteria are even becoming resistant to that antibiotic as well. Fortunately, assistant professor of microbiology and molecular biology, Dr. Bradford Berges, and his team from Brigham Young University may have discovered and designed a secret weapon against MRSA: bacteriophage.

Bacteriophage are viruses specifically evolved to infect bacteria. They are target-specific, so they can easily be designed to attack a particular strain of bacteria - in this case, MRSA. Easy development is a huge advantage to utilizing bacteriophage, considering that making new antibiotics can take years. Bacteriophage are also more helpful than antibiotics in some cases since one dose can go deeper into an infected area than can one dose of antibiotic. Bacteriophage are not flushed out of the body by the immune system in the same way that antibiotics are. Also, bacteriophage won't disturb the good bacteria, like the gut flora that aids in digestion. Lastly, resistance is a huge issue to consider, especially when antibiotic resistance is what led MRSA to be so dangerous. Fortunately, "when resisting bacteria evolve, the assigned phages also evolve, so when super bacterium appears, an equivalent super phage fights it" (Phage.org). 


Dr. Berges and his team tested phage ability to target and kill MRSA on both hard and soft surfaces. They saw 99% kill success in both cases. Berges has also developed "6 unique phage types" that can be used in killing MRSA, a promising statistic considering the future of these studies as potential therapeutic options for MRSA patients. 

According to the Centers for Disease Control and Prevention, MRSA is less life-threatening in "community" infections and are usually seen in skin infections, which are still very infectious. MRSA is more dangerous in the hospital environment, which is brimming with immunocompromised patients (old people, surgery patients). In this case, a MRSA infection could cause sepsis, pneumonia, and even death. Although MRSA can be treated with vancomycin most of the time, this antibiotic has a high minimum inhibitory concentration, meaning it takes a large does to have an impact against the infection. Vancomycin also has less specific targets than other antibiotics (like methicillin), so some host cells are killed along with bacterial cells. Vancomycin treatment is not pleasant for the patient.


As Dr. Berges continues his studies on bacteriophage and their potential action against MRSA, hopefully promising results from more clinical trials will reveal this method as a real potential as a therapeutic option. In addition to killing MRSA themselves, bacteriophage could also target bacterial genes causing resistance. Eliminating these genes could allow antibiotics to continue doing their job, virtually undoing the effect of antibiotic resistance bacterial mutations. 

Watch the video below to learn more about how MRSA spreads and how infections can be prevented. 


Source: Science Daily and Brigham Young University