Even if you fight off a stomach bug, the period of 3-5 days with stomach pains, throwing up, and all sorts of nasty symptoms simply sucks. Infections are horrible to deal with, and with more dangerous antibiotic-resistant strains of bacteria increasing in prevalence, finding a treatment to reliably fight them off is becoming ever-more needed.
Heeding the call, researchers from Baylor College of Medicine, Texas, claim to have developed a phage therapy that can predict where a bacterial infection will occur and fight it off before it becomes a problem. The phage represents a viable option to fight off tough, resistant strains of bacteria in the gut while leaving "good" bacteria unharmed.
Their work was published in the journal mBIO.
“Phages are very specific in their ability to infect and destroy certain species or strains of bacteria and not others, such as good bacteria. In the U.S., phage therapy is increasingly becoming an available option to treat antibiotic-resistant bacterial infections, a serious health concern,” said first author of the study Dr Sabrina Green, director of research and development for TAIL?R labs at Baylor, in a statement.
Bacteriophages, also known as phages, are tiny virus particles that directly target and infect bacteria. After infection, they replicate within the bacterial cells and take over their host’s internal machinery, destroying them in the process. Every 48 hours, 50 percent of all the bacteria on the globe are destroyed by phages – the battle between bacteria and phages is endless.
However, phages may also be a promising alternative to traditional antibiotics. Despite being extremely aggressive towards bacteria, phages are harmless to humans, and so could be harnessed as a preventative antibacterial therapy. Certain bacteria, such as the E. coli strain ExPEC ST131, colonize the gut passively before moving on to other organs, where they subsequently cause serious damage. Preventing them from creating a reservoir in the gut would stop the infection, but the strain is resistant to most available antibiotics.
There is an issue though – a special factor within our intestines, called mucin, prevents phages from attacking bacteria. Sitting as a barrier between all the bacteria in the gut and the intestinal wall, researchers must find a way to avoid mucin for phage therapies to be viable.
In the study, the researchers present a novel phage that binds to the intestinal epithelial cells (the cells that make up the intestine wall) and localizes around specific bacterial cells, all whilst unfazed by mucin. By doing so, it effectively targets bacteria species that may be pathogenic, offering a potential defense against ExPEC ST131 and similar species. Unlike current antibiotics, the phage can do so without killing other gut bacteria, which are vital for maintaining gut health.
“We tested the effect of phage ES17 on its bacterial host ExPEC in a murine intestine, comparing it with phages known to be unable to infect their bacterial host in complex environments,” Green continued.
“We found that only ES17 had the unique ability to target and eliminate ExPEC bacteria in animal models.”
Phage work is in extremely preliminary trials, with most studies currently performed in mice, similar to this study. Trials for such therapies have picked up steam in recent years, with the first clinical trial of intravenous phage approved by the FDA in February 2019. Despite this, most phage therapies struggle to gain approval due to ethical concerns. It remains to be seen whether this will meet the same fate, but phages appear to be a promising avenue for future antibacterial research.