Artificial Sweetener Enhances the Spread of Antibiotic Resistance Genes During Anaerobic Digestion

Artificial sweeteners have been frequently detected inthe feedstocksof anaerobic digestion. As these sweeteners can lead to the shiftof anaerobic microbiota in the gut similar to that caused by antibiotics,we hypothesize that they may have an antibiotic-like impact on antibioticresistance genes (ARGs) in anaerobic digestion. However, current understandingon this topic is scarce. This investigation aimed to examine the potentialimpact of acesulfame, a typical artificial sweetener, on ARGs in anaerobicdigestion by using metagenomics sequencing and qPCR. It was foundthat acesulfame increased the number of detected ARG classes and theabundance of ARGs during anaerobic digestion. The abundance of typicalmobile genetic elements (MGEs) and the number of potential hosts ofARGs also increased under acesulfame exposure, suggesting the enhancedpotential of horizontal gene transfer of ARGs, which was further confirmedby the correlation analysis between absolute abundances of the targetedARGs and MGEs. The increased horizontal dissemination of ARGs maybe associated with the SOS response induced by the increased ROS production,and the increased cellular membrane permeability. These findings indicatethat artificial sweeteners may accelerate ARG spread through digestatedisposal, thus corresponding strategies should be considered to preventpotential risks in practice. Minimalresearch exists on response of ARGs to artificialsweeteners in anaerobic digestion system. This study reports a typicalartificial sweetener enriches ARGs during anaerobic digestion withimplications for controlling antibiotic resistance.