Plain language summary
The importance of the gut microbiota is well recognised. Bacteriophages (viruses targeting bacteria) are highly specific to their target bacteria and are being explored as a means to influence the composition of the gut microflora. This study examined whether and how daily consumption of supplemental Escherichia coli-targeting phages influence the gut microbiota of healthy adults with self-reported gastrointestinal distress. 43 participants were enrolled into this randomised, double-blind, placebo-controlled crossover intervention trial, of which 32 completed both arms (supplement with a mix of 4 bacteriophages specific for E. coli and placebo). Stool and blood samples were tested for microbiota composition, inflammatory markers and plasma lipids. 21 participants had detectable E. coli in their stools at baseline. More subjects had a reduction in E. coli levels with the phage mix than with placebo, although there was considerable variation between individuals. Whilst no changes in microbiota richness and diversity were observed, there was an increase in butyrate producing bacteria and a decrease in potentially pro-inflammatory bacteria. The authors conclude that bacteriophages may have the potential to lead to beneficial changes in the gut microbial composition without causing “global” disruption of the microbiome, as seen after antibiotics.
Abstract
The gut microbiota is increasingly recognized as an important modulator of human health. As such, there is a growing need to identify effective means of selectively modifying gut microbial communities. Bacteriophages, which were briefly utilized as clinical antimicrobials in the early 20th century, present an opportunity to selectively reduce populations of undesirable microorganisms. However, whether intentional consumption of specific bacteriophages affects overall gut ecology is not yet known. Using a commercial cocktail of Escherichia coli-targeting bacteriophages, we examined their effects on gut microbiota and markers of intestinal and systemic inflammation in a healthy human population. In a double-blinded, placebo-controlled crossover trial, normal to overweight adults consumed bacteriophages for 28 days. Stool and blood samples were collected and used to examine inflammatory markers, lipid metabolism, and gut microbiota. Reductions in fecal E. coli loads were observed with phage consumption. However, there were no significant changes to alpha and beta diversity parameters, suggesting that consumed phages did not globally disrupt the microbiota. However, specific populations were altered in response to treatment, including increases in members of the butyrate-producing genera Eubacterium and a decreased proportion of taxa most closely related to Clostridium perfringens. Short-chain fatty acid production, inflammatory markers, and lipid metabolism were largely unaltered, but there was a small but significant decrease in circulating interleukin-4 (Il-4). Together, these data demonstrate the potential of bacteriophages to selectively reduce target organisms without global disruption of the gut community.
Methodological quality
Jadad score
:
3
Allocation concealment
:
Yes
