Lactobacillus rhamnosus strains of oral and vaginal origin show strong antifungal activity in vitro

Abstract

Background: Intake of probiotic bacteria may prevent oral Candida infection. Objective: To screen the antifungal activity of 14 Lactobacillus candidate strains of human origin, against six opportunistic C. albicans and non-albicans species. A second aim was to study the acid production of the four strains showing the strongest antifungal activity. Methods: We used an agar overlay growth inhibition assay to the assess the antifungal activity of the lactobacilli. The acid-producing capacity was measured with pH micro-sensors. Results: All 14 Lactobacillus candidates inhibited the growth of the Candida spp. The four best-performing strains were L. rhamnosus DSM 32992 (oral origin), L. rhamnosus DSM 32991 (oral), L. jensenii 22B42 (vaginal), and L. rhamnosus PB01 (vaginal). The difference between L. rhamnosus DSM 32992 and the other three strains was statistically significant (p < 0.001). The Candida spp. differed in susceptibility; C. parapsilosis was highly inhibited, while C. krusei was not or slightly inhibited. The oral L. rhamnosus DSM 32992 and DSM 32991 strains showed the lowest pH-values. Conclusion: Screening of probiotic lactobacilli showed significant strain-dependent variations in their antifungal capacity in a pH-dependent mode. Two strains of oral origin were most effective. A further characterization seems justified to elaborate on their probiotic properties.

Potential Anti-fungal Activity of Lactobacilli Probiotic Against Fluconazole Resistant Candida albicans Clinical Isolates

“…In our study, L. plantarum (DSM 20174) and L. Casei showed a weak and/or no anti-Candida activity against C. albicans isolates tested. However, other studies have been established the anti-Candida activity of both species 50,51 Our results can be explained by antimicrobial activity of lactobacilli is strain dependent 52 .…”

“…We choosed L. rhamnosus ATCC 7469 for subsequent experiment as it exhibited potent activity against majority of C. albicans isolates. Recent study by Rose Jørgensen et al reported that L. rhamnosus strains exhibited the best growth inhibition activity among tested strains against candida spp 52 .…”

Bacterial-fungal metabolic interactions within the microbiota and their potential relevance in human health and disease: a short review

“… 65 In studies, the best inhibitory effect of lactobacilli strains on Candida growth is associated with the highest organic acid production. 62 By acidifying the environment, lactic and acetic acids seem to be able to significantly prevent Candida spp . growth and therefore pathology onset.…”

“…suggested that a low pH prevents C. albicans from undergoing the yeast-hyphal transition, leading to energy consumption, growth inhibition and cell death. 62 When chronically exposed to acidic stress, C. albicans exhibits a transcriptional shift, notably in iron homeostasis-involved genes. Interestingly, Cottier et al .…”

Rastreio da atividade anti-candida por bactérias do ácido láctico em amostras de saliva de indivíduos saudáveis

“…Noutro estudo, dois isolados orais, L. rhamnosus DS32992 e DSM32991 foram os que mostraram ser os mais ativos contra células planctónicas de Candida spp. [5]. Conclusões: A microbiota oral parece ser uma fonte de bactérias do ácido láctico com atividade contra agentes causadores de candidíase oral.…”