According to this article (https://gut.bmj.com/content/64/10/1562), bacterial levels and microbiome community composition were restored 14 days after bowel cleansing for a colonoscopy. At this time, there is a lack of scientific evidence regarding the impact of colonics/enemas on the microbiome. Therefore, the most conservative approach is to wait 14 days after colonoscopy, colonic, or enema before collecting stool sample.
How long does it take for bacterial levels to be restored after a colonoscopy procedure, colonic, or enema?
Adair