Recent evidence suggests that the gut microbiome may be altered by the intake of artificial sweeteners. The goal of this study was to examine the effects of sucralose, an artificial sweetener, on two gut bacteria; Enterobacter aerogenes and Escherichia coli. Strains of each bacterium were established by long term culturing in three different concentrations of sucralose in addition to maintaining a control wild-type strain cultured for the same amount of time in the absence of sucralose. The growth rate of each strain was determined in the presence and absence of 150mM sucralose and compared to the control strain. The growth of the control E. coli strain was completely inhibited in the presence of sucralose, while E. coli cells chronically adapted to 150mM sucralose showed a lack of growth inhibition. The growth of the control E. aerogenes strain was also inhibited in the presence of sucralose, but to a lesser degree than observed for E.coli. In addition to examining the growth of these two strains in isolation, E. coli and E. aerogenes were studied in co-culture. In the presence of any concentration of sucralose tested, E. aerogenes was able to rapidly and completely out-compete E. coli, while similar major shifts in the co-culture composition were not observed in the absence of sucralose. These findings suggest that observed alterations to the gut microbiome composition in response to sucralose exposure may be due to the way this compound differentially inhibits various species of bacteria.
Importance
Recent evidence has shown that artificial sweeteners, including the artificial sweetener sucralose, can alter the gut microbiome composition, potentially leading to negative health effects for individuals consuming large quantities of this compound. However, the specific effects of sucralose on individual strains of gut bacteria have not been extensively studied. The results presented here show that sucralose differentially inhibits the two gut bacteria E. coli and E. aerogenes, allowing E. aerogenes to overtake a co-culture of the two bacteria. In addition, it is shown that both E. coli and E. aerogenes can adapt to the presence of inhibitory concentrations of sucralose. The results here suggest that increased consumption of artificial sweeteners may alter the gut microbiome by selectively inhibiting certain species of gut bacteria.
(This is an online early publication. Submitted: 10 Oct 2017. Accepted: 11 Dec 2017. A formatted version of this paper will be posted June 2018.)
