Protective Activity of Probiotic Bacteria Against Candida albicans: An In Vitro Study

Background: Therapeutic applications of probiotics against human candida infections remain controversial. Candida species are the most common human fungal pathogens that cause both superficial and systemic infection. Given the low number of appropriate and effective antifungal drugs, the continuing increase in the incidence of Candida infections, and increased drug resistance, it is required to explore new and better factors targeting essential biological processes and pathogenic determinants of C. albicans. Objective: In this context, a laboratory study was conducted to investigate the effects of probiotic Lactobacillus acidophilus on the adherence of C. albicans to the human epithelial cell line known as human epithelial type 2 (HEp-2) cells and the potential protective effects of probiotic bacteria on the infected cells. Materials and Methods: To evaluate the effect of L. acidophilus on the adherence of C. albicans to HEp-2 cells, either yeast cells, probiotic bacteria, or both were added to each well of a 12-well plate, with a coverslip at the bottom, covered with a semiconfluent layer of HEp-2 cells. After 2 hours of incubation, the number of adhered pathogens was counted using light microscopy. In order to determine the effect of C. albicans on the viability of the HEp-2 cells, in the presence and absence of L. acidophilus, MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay was conducted. Results: The results revealed that either L. acidophilus strain La5 or C. albicans adhered to the (HEp-2) cells. In addition, cell association of C. albicans with Hep2 cells decreased by up to 80% when probiotic bacteria were added. The most interesting finding was that in the presence of L. acidophilus La-5, a significant decrease was observed in the adhesion of C. albicans to the cell line or cell mortality. Conclusion: According to the results of the study, the use of probiotics is a promising method to decrease the pathogenicity of opportunistic mycoses