Anticandidal Activities by Lactobacillus Species: An Update on Mechanisms of Action

Abstract

Lactobacilli are among the most studied bacteria in the microbiome of the orodigestive and genitourinary tracts. As probiotics, lactobacilli may provide various benefits to the host. These benefits include regulating the composition of the resident microbiota, preventing – or even potentially reverting- a dysbiotic state. Candida albicans is an opportunistic pathogen that can influence and be influenced by other members of the mucosal microbiota and, under immune-compromising conditions, can cause disease. Lactobacillus and Candida species can colonize the same mucosal sites; however, certain Lactobacillus species display antifungal activities that can contribute to low Candida burdens and prevent fungal infection. Lactobacilli can produce metabolites with direct anticandidal function or enhance the host defense mechanisms against fungi. Most of the Lactobacillus spp. anticandidal mechanisms of action remain underexplored. This work aims to comprehensively review and provide an update on the current knowledge regarding these anticandidal mechanisms.

Candida albicans and Enterococcus faecalis biofilm frenemies: When the relationship sours

“…In addition, many genes involved in arginine and lysin biosynthesis were induced in C. albicans under mild oxidative stress [ 7 , 30 , 62 ]. Considering that E. faecalis is a lactic acid bacteria [ 63 ], the similarities observed in C. albicans transcriptional response to E. faecalis , L. crispatus , and weak organic acids, and the fact that acidic environment favours yeast growth [ [64] , [65] , [66] ], then we hypothesized that C. albicans biofilm and hyphal morphogenesis inhibition observed in dual-species biofilms is pH dependant phenomenon.…”

Probiotics for Oral Candidiasis: Critical Appraisal of the Evidence and a Path Forward

“…Experimental work has provided evidence of several anti- Candida activities of Lactobacillus spp. that negatively affect C. albicans virulence characteristics including growth, yeast to hyphae transition, adhesion, and biofilm development [ 44 , 45 ]. Antifungal mechanisms include production of acids, hydrogen peroxide, bacteriocins, and biosurfactants, as well as competition for adhesion sites.…”

Insights From the Lactobacillus johnsonii Genome Suggest the Production of Metabolites With Antibiofilm Activity Against the Pathobiont Candida albicans

“…As the effectiveness of conventional antifungals is diminished, novel strategies are being developed, such as probiotic therapies ( Mundula et al, 2019 ). In this regard, several species from the Lactobacillus complex genus have been studied as probiotic therapies in gastrointestinal, vulvovaginal, and oral Candida infections in mouse models and human clinical trials ( Vazquez-Munoz and Dongari-Bagtzoglou, 2021 ). This is due to the fact that certain lactobacilli produce soluble metabolites—i.e., bacteriocins, weak organic acids (such as lactic and acetic acids), and biosurfactants with anticandidal properties ( Vazquez-Munoz and Dongari-Bagtzoglou, 2021 ).…”

“…In this regard, several species from the Lactobacillus complex genus have been studied as probiotic therapies in gastrointestinal, vulvovaginal, and oral Candida infections in mouse models and human clinical trials ( Vazquez-Munoz and Dongari-Bagtzoglou, 2021 ). This is due to the fact that certain lactobacilli produce soluble metabolites—i.e., bacteriocins, weak organic acids (such as lactic and acetic acids), and biosurfactants with anticandidal properties ( Vazquez-Munoz and Dongari-Bagtzoglou, 2021 ). Antifungal activities vary across Lactobacillus species and even among strains ( Strus et al, 2005 ; Jang et al, 2019 ); hence, the studies on relatively unexplored species, such as Lactobacillus johnsonii , and newly isolated strains within this species are novel and can unravel potentially significant probiotic properties.…”

“…Sucrose significantly enriched the L. johnsonii communities on the oral mucosa during infection with C. albicans and caused a reduction in fungal burdens ( Bertolini et al, 2021 ). Since other Lactobacillus species are antagonistic to Candida ( Vazquez-Munoz and Dongari-Bagtzoglou, 2021 ), we hypothesized that L. johnsonii might exert a growth inhibitory effect on C. albicans . Lactobacillus johnsonii are Gram-positive, facultatively anaerobic, non-motile bacteria that are part of the L. acidophilus group.…”