Elevator Pitch

• A 30-day self-experiment using 16S nanopore sequencing found no detectable L. reuteri colonization from BioGaia Prodentis, despite notable shifts in other oral bacteria.

Key Takeaways

• No L. reuteri was detected in any sample, suggesting no colonization, only transient presence, or levels below detection.
• The oral microbiome shifted substantially, most notably a large rise in S. salivarius (peaking one week after stopping the probiotic) alongside changes consistent with ecological interactions (e.g., Veillonella).
• Oral microbiome sequencing was convenient and informative (including checking for gum-disease–associated “red complex” bacteria, which were absent).

Most Memorable Quotes

• “There was no L. reuteri found in any of the samples.”
• “Even though the probiotic itself didn't show up, the oral microbiome did change quite a lot.”
• “The oral microbiome is dynamic, with huge swings in species abundance over a timeframe of just weeks”