“Survivability of probiotic CA15 strain with and without fluconazole co-administration and its effect on gut microbiota and metabolome through SHIME® model” is the title of the study that has been published recently which examines the behavior of the probiotic strain L. rhamnosus CA15 under simulated gastrointestinal conditions, including in the presence of the antifungal drug fluconazole.
Probiotic CA15: how does it behave in the gut and alongside drug treatments?
The study evaluated the ability of the probiotic L. rhamnosus CA15 to survive along the gastrointestinal tract and its impact on gut microbiota composition and the metabolome, using the dynamic in vitro SHIME® model, which simulates conditions in the human digestive system.
The researchers considered both fasted and fed conditions and also investigated co-administration of the antifungal fluconazole. The colonic phase was monitored for up to 24 hours, assessing the presence of the CA15 strain using a strain-specific RT-qPCR technique and, in parallel, analyzing microbiota (16S rRNA) and metabolome profiles.
Key findings
The results showed that:
- Fasting conditions did not impair the survival of the CA15 strain in the ileal phase.
- Co-administration of fluconazole did not reduce the viability of the probiotic.
However, fluconazole alone caused significant changes in the microbiota of the colonic fraction, including:
- a reduction in the Firmicutes
- an increase in the Proteobacteria
and a decrease in several genera, such as Dorea, Mitsuokella, Lactobacillus, Oscillospiraceae UCG-002, Bifidobacterium, as well as the Christensenellaceae_R-7_group and Eubacterium hallii.
When the CA15 strain was administered together with fluconazole in the colonic fraction, these antifungal-induced alterations were largely counteracted.
In addition, the presence of CA15 led to a significant increase in several beneficial metabolites, including volatile organic compounds and short- and branched-chain fatty acids, particularly heptanoic, acetic, propanoic, and isobutyric acids.
Conclusions
Overall, the L. rhamnosus CA15 strain showed:
- good survivability along the simulated gastrointestinal tract, under both fasted and fed conditions
- a positive modulatory effect on gut microbiota and the metabolome
- the ability to help counterbalance microbial imbalances induced by fluconazole treatment
The use of the dynamic SHIME® model made it possible to gain valuable insights into the delivery and performance of the CA15 probiotic strain in the gastrointestinal tract, supporting its potential as a functional probiotic.
Read the full article here: https://www.sciencedirect.com/science/article/pii/S0963996925020952