Efficacy of vitamin B complex as an adjuvant therapy for the treatment of complicated vulvovaginal candidiasis: An in vivo and in vitro study

The dawn of repurposing vitamins as potential novel antimicrobial agents: A call for global emergency response amidst AMR crisis

Amidst, the global pandemic of antimicrobial resistance (AMR), the rate at which AMR increases overwhelms the increased efforts to discover new effective antimicrobials. There is a persistent need for alternative treatment modalities so as to keep up with the pace. AMR is the leading cause of death in the world and its health and economic consequences suggest the urgent need for sustainable interventions. Vitamins have consistently proven to have antimicrobial activity as well as slowing down the AMR rate by influencing the AMR genes even towards extensive multidrug resistant strains. Evidences suggest that the use of some vitamins on their own or in combination with existing antimicrobial agents could be a breakthrough towards combating AMR. This will widen the antimicrobial agents' options in the treatment arena, preserve the antimicrobial agents susceptible to develop resistant so that they can be used in severe infections only, reduce the tension and burden of the AMR crisis significantly and give enough room for development of new antimicrobial agents. Moreover, almost all viral, fungal, parasitic and bacterial resistant strains of concern as listed by World Health Organization have been found to be sensitive to several vitamins either synergistically with other antimicrobials or independently. Considering their widened spectrum of immunomodulatory and antimicrobial effect, some vitamins can further be repositioned as prophylactic antimicrobial agents in clinical situations like in presurgeries prophylaxis so as to avoid unnecessary use of antimicrobials especially antibiotics. Various relevant AMR stakeholders should invest in clinical trials and systematic reviews with available data to enable quick repositioning of some potential vitamins as antimicrobial agents as an emergency rapid response towards AMR Crisis. This includes the preparation of guidelines containing specificity of which vitamin to be used for treatment of which type of infection.

Riboflavin Targets the Cellular Metabolic and Ribosomal Pathways of Candida albicans In Vitro and Exhibits Efficacy against Oropharyngeal Candidiasis

Oropharyngeal candidiasis (OPC), which has a high incidence in immunocompromised and denture stomatitis patients, is commonly caused by Candida albicans infection and in some cases develops into disseminated candidiasis throughout the throat and esophagus, resulting in high mortality. New drugs are needed to combat OPC because of the limited treatment options currently available and increasing resistance to existing drugs. Here, we confirmed that riboflavin (RF), a cofactor of flavin adenine mononucleotide and flavin adenine dinucleotide, has broad-spectrum anti-Candida activity. The formation of C. albicans hyphae and biofilm was inhibited by RF. Mechanistically, RF disrupted membrane and cell wall integrity, as well as promoting reactive oxygen species and pyruvate accumulation. Furthermore, RF targeted multiple essential pathways via functional disruption of thiamine and RF metabolic pathways, central carbon metabolism, and ribosome metabolism. Similar to the results in vitro, the inhibitory effect of RF on C. albicans hyphae was confirmed in a mouse model of OPC. Moreover, after 5 consecutive days of intraperitoneal injection, RF exhibited therapeutic efficacy, as demonstrated by phenotype investigation, the fungal burden, and histopathological analysis. These findings revealed that RF exerts a multifaceted anti-Candida effect and has potential benefits in the treatment of OPC. IMPORTANCE Candida species are common pathogens in fungal infections, causing mucosal infection and invasive infection in immunodeficient patients. Given the limited classes of drugs and resistance to these drugs, new antifungal agents need to be developed. Drug repurposing is a potential method for antifungal drug development. This study demonstrated that riboflavin (RF) exhibited broad-spectrum anti-Candida activity. RF affected multiple targets involving the membrane and cell wall integrity, the accumulation of reactive oxygen species and pyruvate, and the altered metabolic pathways in C. albicans. Moreover, RF exhibited efficacy in the treatment of C. albicans in an oropharyngeal candidiasis mouse model. Taken together, the antifungal activity and the promising clinical application of RF were highlighted.

Plasma-based strategy for inhibiting Candida albicans growth and CaMCA1 gene expression in vitro and reducing fungal pathogenicity in a murine model of vulvovaginal candidiasis

Vulvovaginal candidiasis (VVC) is a common mucosal infection, mainly caused by Candida albicans. The use of common antifungal drugs in treatment of VVC is limited due to emergence of resistant fungal strains and severe side effects. Cold atmospheric plasma (CAP) as a novel therapeutic approach is proven to display strong antifungal activity against C. albicans. In the present study, the effects of CAP treatment on virulence and pathogenicity of C. albicans in a murine model was investigated. Candida albicans was treated with CAP at different time exposures. Fungal cell morphology and the expression profile of CaMCA1 gene in CAP-treated fungus was evaluated using electron microscopy and quantitative RT-PCR. Moreover, the mice model of VVC was developed using CAP-treated and non-treated C. albicans and characterized in terms of vaginal fungal burden, the rate of hyphae formation in the vaginal tissue and fluid and the inflammation degree of mice vaginal tissue. Significant reduction in CaMCA1 expression and remarkable mitochondrial degradation were observed in CAP-treated C. albicans cells. The lowest fungal burden, reduced hyphae formation, poor adherence of yeast cells to vaginal epithelium, and the low degree of inflammation were observed in mice infected with CAP-treated C. albicans. Suppression of CaMCA1 gene and mitochondrial degradation in CAP-treated C. albicans yeast cells may diminish yeast to hyphae transition and reduce fungal pathogenicity in murine model of VVC. CAP treatment can be considered as a novel and efficient therapeutic strategy against C. albicans and related Candida infections in practice.

LAY SUMMARY

CAP was successfully used to inhibit fungal growth and CaMCA1 gene expression in C. albicans. It caused morphological alterations in membranous structures of the yeast cells and finally led to the cell death. CAP meaningfully reduced C. albicans virulence and pathogenicity in a murine model of VVC.