Antifungal effects of Lactobacillus rhamnosus to Candida tropicalis: An in vitro study

Candida is known to cause various diseases due to its ability to colonize mucosal surfaces and other sites of the body. Lactobacillus rhamnosus, on the other hand, creates an antagonistic pattern to reduce inflammation against fungal organisms by inducing metabolic changes in the fungus. Through this, the study aimed to investigate and understand the inhibitory effects of Lactobacillus rhamnosus to Candida tropicalis and ultimately correlate its effect in comparison to nystatin. Pure cultures of L. rhamnosus and C. tropicalis were used in the experimentation.  In the study, it was shown that both species exhibit co-aggregation, thus had potential in competitive exclusion. To explore the inhibitory effect of L. rhamnosus, agar well diffusion assay was utilized to visualize inhibition zones of each concentration: 10³, 10⁵, 10⁷, and 10⁹. In the results of this assay, L. rhamnosus has shown inhibitory effects most optimally in 10⁹ CFU/mL concentration. In comparison to nystatin, 10⁷ and 10⁹ CFU/mL had shown same/greater inhibition zones. Furthermore, this test exemplified that higher concentrations tend to have greater inhibition zones. To further examine the effect, agar overlay interference test was utilized. This was to show bacterial growth inhibition. In the results of this test, it was shown that all concentrations except 10³ CFU/mL had shown inhibition in terms colony size. In brief, Lactobacillus rhamnosus exhibited antifungal activity against Candida tropicalis and has statistically exemplified the same inhibitory effect to nystatin. Moreover, the results reconfirms that the inhibitory effect of L. rhamnosus is dependent on its concentration.

published by the  International Journal of Biosciences | IJB