Human Gut Microbial Strains Reduce Inorganic Arsenic Concentrations in In Vitro Culture Models

In this study, individual gut bacterial species were tested to determine whether common strains in the human gut can alter arsenite [As(III)] concentrations under anaerobic conditions. Bacterial strains were cultured and exposed to As(III) and resulting concentrations were quantified using ICP-MS. Results revealed significant species-specific reductions in As(III) concentrations. While some bacterial strains exhibited limited effects, other strains including Phocaeicola massiliensis Parasutterella excrementihominis, Bacteroides ovatus, Parabacteroides merdae, and Acidaminococcus intestini, significantly reduced As(III) concentrations relative to controls. Notably, P. massiliensis demonstrated the strongest effect, reducing arsenic levels to approximately 37% of control values. These findings suggest that specific members of the gut microbiome may play a role in arsenic transformation or sequestration with potential implications for host exposure and toxicity. Further research is necessary to elucidate specific strain mechanisms in reducing As(III) concentrations as well as these strains’ potential as target microbiome-interventions. This study highlights the importance of specific microbial strains that can determine arsenic bioaccessibility within the gut environment, indicating potential gut microbiome therapeutics in mitigating arsenic toxicity.