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IntroductionAntifungal agents are not always efficient in resolving vulvovaginal candidiasis (VVC), a common genital infection caused by the overgrowth of Candida spp., including Candida albicans, or in preventing recurrent infections. Although lactobacilli (which are dominant microorganisms constituting healthy human vaginal microbiota) are important barriers against VVC, the Lactobacillus metabolite concentration needed to suppress VVC is unknown.MethodsWe quantitatively evaluated Lactobacillus metabolite concentrations to determine their effect on Candida spp., including 27 vaginal strains of Lactobacillus crispatus, L. jensenii, L. gasseri, Lacticaseibacillus rhamnosus, and Limosilactobacillus vaginalis, with inhibitory abilities against biofilms of C. albicans clinical isolates.ResultsLactobacillus culture supernatants suppressed viable fungi by approximately 24%-92% relative to preformed C. albicans biofilms; however, their suppression differed among strains and not species. A moderate negative correlation was found between Lactobacillus lactate production and biofilm formation, but no correlation was observed between hydrogen peroxide production and biofilm formation. Both lactate and hydrogen peroxide were required to suppress C. albicans planktonic cell growth. Lactobacillus strains that significantly inhibited biofilm formation in culture supernatant also inhibited C. albicans adhesion to epithelial cells in an actual live bacterial adhesion competition test.Discussion Healthy human microflora and their metabolites may play important roles in the development of new antifungal agent against C. albicans-induced VVC.

A 79-year-old Japanese man who had undergone thoracic aortic replacement 10 years prior presented with a 3-day history of sore throat. He was initially diagnosed with pharyngitis; however, multiple emboli in the vessels of the left side of the body were recognized. He was diagnosed with thoracic aortic graft infection caused by Candida albicans, with multiple embolisms. Anti-fungal therapy was initiated, but surgical removal of the graft was not performed because of the high risk associated with the operation, and he eventually died. Inappropriate use of antibiotics might have led to a severe fungal infection. As such, the inappropriate use of antimicrobial agents should be avoided.

We developed a decision support system that helps doctors select appropriate first-line drugs. The system classifies patients' abilities to protect themselves from infectious diseases as a risk level for infection. In an evaluation of the prototype system, the risk level it determined correlated with the decisions of specialists. The system is very effective and convenient for doctors to use.