Ancient Bacteria-Killing Virus Holds Evolutionary Secret Against Antibiotic Resistance

The emergence of antibiotic-resistant bacteria is a common concern in hospitals worldwide, and is the evolutionary result of the selective pressures caused by our extensive use of antibiotics to fight bacterial infections.

Scientists are often fighting the losing battle against antibiotic-resistant bacteria, with every new antibiotic treatment outwitted by the bacteria’s uncanny ability to adapt to whatever adversity comes their way. Although bacteria’s evasive strategies may have outwitted scientists in the last century, their strategies still fall prey to the nature’s billion-year old bacteria-killing virus known as bacteriophages.

According to a recent PLOS One article, bacteriophages have long evolved a way to kill bacteria for good, specifically by targeting an essential and evolutionarily conserved component of any bacteria: the bacteria’s cell wall

Why is the bacteria cell wall so important? It turns out that all bacteria have a high salt/ion content relative to their environment, attracting the influx of water through their water channels, and causing the bacteria to swell up. Much like an inflated balloon, the unabated swelling can cause the bacteria to lyse (or blow up); a process that is physically hindered by the confines of the universal cell wall found in virtually any bacterial strains throughout evolution.

Consequently, bacteriophages have evolved to kill any bacteria by breaking down the cell wall, causing the bacteria to swell and lyse; releasing bacteriophage progeny in the process. Because the cell wall is so important for the survival of bacteria throughout evolution, it is no surprise that there are no bacterial strains in the last billion years that can resist the onslaught of bacteriophage infection.

Exploiting nature’s wisdom to undercut bacteria’s evasive strategies, Dr. Vincent A. Fischetti at Rockefeller University and colleagues developed a new drug that suppresses the building and maintenance of the bacteria cell wall. The drug, named Epimerox,works by suppressing a key enzyme crucial for the membrane building process known as 2-epimerase; an enzyme found in virtually all bacterial strains including the methicillin (antibiotic)-resistant S. aureus (MRSA) found commonly in hospitals. Fischetti further reported that Epimerox can effectively kill MRSA, as well as a number of bacterial strains, all without causing any detectable emergence of Epimerox-resistance.

The study suggests that Epimerox may be the first broad-acting antibiotic that can significantly reduce the probability for antibiotic-resistance.

The discovery of Epimerox is a breakthrough in microbial control, an elixir that can help undo the evolutionary damage done by our extensive use of antibiotics in the past. 

Schuch et al., Use of a Bacteriophage Lysin to Identify a Novel Target for Antimicrobial Development. PLOS ONE. April 2013. 10.1371/journal.pone.0060754