The effect of probiotic Lactobacillus rhamnosus GG on Candida albicans and Candida tropicalis biofilm formation: A preliminary study

Abstract

Lactobacillus rhamnosus are Gram-positive and lactic acid-producing bacteria. Meanwhile, Candida albicans and Candida tropicalis are opportunistic fungi that cause oral candidiasis. This study aimed to determine the effect of LGG on the biofilm formation of C. tropicalis and C. albicans with the hypothesis that LGG inhibits the biofilm of the yeasts. C. albicans ATCC MYA-4901 and C. tropicalis ATCC 13803 were standardised to 1x106 cells to form a mono-species biofilm. L. rhamnosus GG (LGG) was standardised to 1x107 cells, equivalent to absorbance 0.5 at OD620nm.  The microorganisms were cultivated in nutrient broth in a 96-well plate and incubated at 37°C for 24 h and 48 h. Co-culture biofilm was developed by combining Candida spp. with LGG in the same well at a similar concentration as the mono-culture.  Crystal violet assay was conducted to assess the biofilm biomass with absorbance measured at OD620nm wavelength. After 24 hours, polymicrobial biofilms of C. albicans with LGG decreased by 37.1 ± 9.2%. At 48 hours, it further decreased to 44.7 ± 5.9%. For C. tropicalis, co-culture biofilms with LGG decreased by 16.3 ± 5.9% and 35.7 ± 7.6% after 24 h and 48 h incubation, respectively. LGG significantly reduced C. albicans biofilm compared to C. tropicalis (P<0.05).  In conclusion, LGG has antibiofilm activity against C. albicans and C. tropicalis.  However, further study is needed to conclude the effect against other species strains.