Inhibitory effects of Lactobacillus casei Shirota against both Candida auris and Candida spp. isolates that cause vulvovaginal candidiasis and are resistant to antifungals

Aline Lorenzoni Paniágua; Amabel Fernandes Correia; Lívia Custódio Pereira; Bruna Maciel de Alencar; Fabiana Brandão Alves Silva; Rosane Mansan Almeida; Yanna Karla de Medeiros Nóbrega

doi:10.1186/s12906-021-03405-z

Inhibitory effects of Lactobacillus casei Shirota against both Candida auris and Candida spp. isolates that cause vulvovaginal candidiasis and are resistant to antifungals

BMC Complement Med Ther. 2021 Sep 23;21(1):237. doi: 10.1186/s12906-021-03405-z.

Authors

Aline Lorenzoni Paniágua¹, Amabel Fernandes Correia², Lívia Custódio Pereira³, Bruna Maciel de Alencar¹, Fabiana Brandão Alves Silva¹, Rosane Mansan Almeida⁴, Yanna Karla de Medeiros Nóbrega¹

Affiliations

¹ Clinical Microbiology and Immunology Laboratory, Department of Pharmacy, University of Brasilia, Campus Darcy Ribeiro, Brasilia, DF, 70910-900, Brazil.
² Central Public Health Laboratory of the District Federal (LACEN-DF), Medical Biology Management, Center of Parasitology and Mycology, Brasília, DF, Brazil.
³ Vulvar Pathology Clinic, Department of Gynecology, Brasilia University Hospital, University of Brasilia, Brasilia, DF, Brazil.
⁴ Clinical Microbiology and Immunology Laboratory, Department of Pharmacy, University of Brasilia, Campus Darcy Ribeiro, Brasilia, DF, 70910-900, Brazil. rmansan@gmail.com.

Abstract

Background: Vulvovaginal candidiasis (VVC), the second leading cause of genital infection in women of reproductive age, is caused by yeasts of the genus Candida. Treatment is usually empirical and performed with azoles, which have shown increasing ineffectiveness due to resistance from these species. This therapeutic challenge has led to the search for new treatment strategies. Lactobacillus spp. produce several components with microbicidal effects, such as lactic acid. These species are the main components of a healthy vaginal microbiota and have been used as probiotics. The aim of this work was to investigate the in vitro inhibitory effects of Lactobacillus casei Shirota on both the Candida spp. that cause VVC and on C. auris.

Methods: The microbicidal effects of L. casei Shirota on the main VVC-causing species, C. albicans, C. tropicalis, C. norvegensis and C. parapsilosis, in addition to C. auris were investigated by counting the Colony-forming Units (CFUs) after cocultivation. The antifungal activity of lactic acid against these Candida strains was assessed using the microtiter broth dilution method to determine the minimum inhibitory concentrations (MICs). The effects of L. casei Shirota on hyphal and early biofilm formation was measured by optical microscopy.

Results: L. casei Shirota showed inhibitory action against all tested Candida spp., ranging from 66.9 to 95.6% inhibition depending on the species. This inhibition is possibly related to the production of lactic acid, since lactic acid has shown microbicidal action against these same Candida spp. at a concentration of 5 mg/mL, which corresponds to half of the normal physiological concentration. In addition, L. casei Shirota was able to reduce the formation of C. albicans hyphae and early biofilms, showing strong anti-Candida effects.

Conclusions: These results suggest that L. casei Shirota has antifungal activity against the Candida species that cause VVC. L. casei also has microbicidal action against C. auris.

Keywords: Biofilm; C. auris; Candida spp.; Candidiasis; Lactobacillus casei Shiota; Microbicidal effect.

MeSH terms

Antifungal Agents / pharmacology*
Biofilms
Brazil
Candida / drug effects*
Candida albicans / drug effects
Candida auris / drug effects
Candidiasis, Vulvovaginal / drug therapy*
Female
Humans
Lactic Acid / pharmacology*
Lacticaseibacillus casei*

Substances

Antifungal Agents
Lactic Acid