Effects of probiotic bacteria on Candida presence and IgA anti-Candida in the oral cavity of elderly

Abstract

Imbalance in the resident microbiota may promote the growth of opportunistic microorganisms, such as yeasts of Candida genus and the development of diseases, especially in aged people. This study evaluated whether the consumption of the probiotic Yakult LB® (Lactobacillus casei and Bifidobacterium breve) was able to influence on the specific immunological response against Candida and on the presence of these yeasts in the oral cavity of 42 healthy aged individuals. Saliva samples were collected before and after the probiotic use for 30 days, 3 times a week. The samples were plated in Dextrose Saboraud Agar with chloramphenicol, the colony-forming units (CFU/mL) were counted and the Candida species were identified. Anti-Candida IgA analysis was conducted using the ELISA technique. ANOVA and Student's t-test were used for normally distributed data and the Wilcoxon test was used for data with non-normal distribution (α=0.05). The results showed a statistically significant reduction (p<0.05) in Candida prevalence (from 92.9% to 85.7%), in CFU/mL counts of Candida and in the number of non-albicans species after consumption of the probiotic. Immunological analysis demonstrated a significant increase (p<0.05) in anti-Candida IgA levels. In conclusion, probiotic bacteria reduced Candida numbers in the oral cavity of the elderly and increased specific secretory immune response against these yeasts, suggesting its possible use in controlling oral candidosis.

Desequilíbrios na microbiota residente podem promover o crescimento de microrganismos oportunistas, como as leveduras do gênero Candida, e o desenvolvimento de doenças, especialmente na população idosa. Este estudo investigou se o consumo do probiótico Yakult LB® (Lactobacillus casei e Bifidobacterium breve) era capaz de influenciar na resposta imune secretória anti-Candida e na presença destes microrganismos na cavidade bucal de 42 idosas saudáveis. Amostras de saliva foram coletadas antes e depois do consumo do probiótico por 30 dias, 3 vezes por semana. As amostras foram semeadas em Agar Saboraud Dextrose com cloranfenicol, as unidades formadoras de colônias (UFC/mL) foram contadas e as espécies de Candida foram identificadas. A análise de IgA anti-Candida foi realizada pela técnica ELISA. Os resultados demonstraram redução na prevalência de Candida (de 92,9% para 85,7%), na contagem de UFC/mL (p≤0,05) e no número de espécies não-albicans, depois do consumo do probiótico. As análises imunológicas mostraram um aumento significativo dos níveis de IgA anti-Candida (p≤0,05). Concluindo, as bactérias probióticas reduziram significantemente a quantidade de Candida na cavidade bucal dos idosos e aumentaram a resposta imune secretória específica para esta levedura, sugerindo a possibilidade de sua utilização no controle da candidose bucal.