Antibacterial action of bile acids against Helicobacter pylori and changes in its ultrastructural morphology: effect of unconjugated dihydroxy bile acid.
Level 5 - mechanism / opinion, no new human data
In vitro microbiological bench study without human participants.
PubMed 10535483 · doi:10.1007/s005350050374
What was done
The authors evaluated the in vitro antibacterial activity of various unconjugated and conjugated bile acids against laboratory standard strains and clinical isolates of Helicobacter pylori. Minimum inhibitory concentrations (MICs) were measured at 72 hours. Scanning electron microscopy was used to examine ultrastructural morphological changes in H. pylori after 24 hours of exposure to deoxycholic acid and ursodeoxycholic acid at MIC levels.
What was found
Only unconjugated dihydroxy bile acids demonstrated antibacterial activity. The 72-hour MIC was 200–400 µg/ml for deoxycholic acid, similar for chenodeoxycholic acid, and 400–800 µg/ml for ursodeoxycholic acid. Scanning electron microscopy showed H. pylori transitioned from a rodlike shape to a spherical form with surface blebs, progressing to an irregularly condensed mass, a pattern distinct from the spherical morphology induced by amoxicillin.
Why it matters
The findings characterize the specific in vitro inhibitory concentrations and distinct ultrastructural damage inflicted by unconjugated dihydroxy bile acids on H. pylori, providing mechanistic insight into bile-mediated bacterial inhibition.
Limits
This is strictly an in vitro bench investigation with no in vivo or clinical testing. The abstract does not specify the exact sample size or number of strains tested. Potential mucosal toxicity and physiological relevance in the human stomach were not evaluated.
Cited by
- partial TUDCA is an antibacterial bile salt.