Lactobacillus rhamnosus cell-free extract targets virulence and antifungal drug resistance in Candida albicans

Candidiasis caused by multidrug-resistant Candida species continues to be difficult to eradicate. The use of live probiotic bacteria has gained a lot of interest in the treatment of candidiasis; however, whole-cell probiotic use can often be associated with a high risk of sepsis. Strategies manipulating cell-free methods using probiotic strains could lead to the development of novel antifungal solutions. Therefore, we evaluated the effect of three probiotic cell-free extracts (CFEs) on the growth, virulence traits, and drug efflux pumps in C. albicans. On the basis of its minimum inhibitory concentration, Lactobacillus rhamnosus was selected and assessed against various virulence traits and drug resistance mechanisms. The results showed that L. rhamnosus CFE significantly inhibited hyphae formation and reduced secretion of proteinases and phospholipases. Moreover, L. rhamnosus inhibited the drug efflux proteins in resistant C. albicans strains thus reversing drug resistance. Gene expression data confirmed downregulation of genes associated with microbial virulence and drug resistance following treatment of C. albicans with L. rhamnosus CFE. Through gas chromatography - mass spectrometry chemical characterization, high contents of oleic acid (24.82%) and myristic acid (13.11%) were observed in this CFE. Collectively, our findings indicate that L. rhamnosus may potentially be used for therapeutic purposes to inhibit C. albicans infections.