I did find a study, using mice, that said:
the artificial sweetener saccharin could alter gut microbiota and induce glucose intolerance, raising questions about the contribution of artificial sweeteners to the global epidemic of obesity and diabetes.
It also gave reference to another study:
A previous study found that consumption of Splenda, a nonnutritive sweetener containing 1% sucralose, impaired the growth of gut bacteria in rats [18].
Aspartame and sucralose are sold under the brand name Splenda.
But I will also re-emphasize that they are comparing rodents to humans, for what itās worth.