A new clinical study confirmed the safety and tolerability of using bacteria-specific viruses known as bacteriophages to eliminate disease-causing bacteria in the gut.

Antibiotics’ days might be numbered as viruses that kill harmful gut bacteria could represent a real alternative to the conventional treatment. The new treatment could be used in place of antibiotics to rid the gut of harmful bacteria and promote the growth of beneficial bacteria that are known to enhance gastrointestinal health, immune function and anti-inflammatory processes.

"People taking antibiotics can develop resistance and experience gastrointestinal distress since antibiotics kill both bad and good bacteria in the gut," said study co-investigator Taylor C. Wallace from the George Mason University. "Using viruses that infect only specific types of bacteria spares the many good bacteria in the gut, which are linked to numerous long-term beneficial health outcomes. We have shown for the first time that bacteriophage treatment has no apparent side effects, at least with short-term use."

The results from the Bacteriophage for Gastrointestinal Health (PHAGE) Study, the first clinical study in the Western hemisphere to provide patients with bacteriophages, were presented at the American Society for Nutrition annual meeting, Nutrition 2018, held in Boston.

The research included 31 people who reported significant gastrointestinal distress at the beginning of the study, but who were not diagnosed with any specific gastrointestinal disorder. Study participants were assigned to either a placebo or treatment group for the first four weeks of the study, followed by a two-week washout period and an additional four weeks on the opposite treatment. The treatment group received four bacteriophage strains that specifically eliminate E. coli, a pathogen that can contribute to gastrointestinal irregularities and stomach upset.

The researchers reported that the study participants tolerated the bacteriophage treatment extremely well, with no adverse events reported during the four weeks of treatment. During the bacteriophage treatment, they observed significant decreases in interleukin 4, an inflammatory marker often associated with allergic response. There were also changes in differential abundance of several other gut bacterial species, including reductions in Clostridium perfringens and increases in several health-promoting bacterial species. Within a small subset of individuals with two or more risk factors for metabolic syndrome, there was also an increase in beneficial Bifidobacterium spp.

The team said that bacteriophages might also be useful for eliminating nutritional deficiencies due to chronic diarrhea in developing countries and are seeking larger-scale support to test which strains might be best for this application. Chronic diarrhea and associated malnutrition are the second most common causes of childhood death worldwide.