Effects of Farnesol on Drug-Resistant and Non-Resistant <i>Candida albicans</i>: Implications for Cosmetic and Pharmaceutical Applications

Background: Farnesol is added to numerous consumer products that intentionally, or inadvertently come in contact with tissues that may harbor the opportunistic yeast, Candida albicans. Objective: This study explores biological consequences of the exposure of Candida albicans from community infections or from a panel of antifungal drug resistant organisms on growth and survival of these organisms when exposed to farnesol. Methods: ATCC supplied Candida albicans from the MP8 drug resistance panel and an additional 12 strains of community-acquired Candida albicans were cultured in the presence of farnesol. With standard micobiologic techniques and flow cytometry evaluation, a series of experiments considered growth, morphology, viability and entrance into the quiescent persister phenotype of Candida with emphasis on differences between drug resistant and community organisms. Results: Differences growth yield, relative cell size and heat susceptibility distinguished the community organisms from the drug-resistant organisms. Using a subset of these organisms, exposure to farnesol resulted in diminished growth, inhibited hyphal growth, diminished cell membrane integrity and increased heat stress susceptibility. Data provided suggest that exposure to farnesol pushes cultures of Candida albicans toward the quiescent persister phenotype. Conclusion: Exposure of drug resistant and community strains of Candida albicans are modestly affected by farnesol in ways that may lessen their pathogenic potential. In contrast, the tendency of farnesol to engender greater numbers of quiescent organisms could support persistence of Candida.

Preclinical Evaluation of Pharmaceutical Compositions and Their Components for Urinary Health

Background: The need for products that treat or prevent urinary tract infections without resort to antibiotics that may select for resistant bacterial strains has created a need to develop antibiotic-free therapeutics. Objective: To conduct an exploratory evaluation of intrinsic antimicrobial activity of a panel of compounds alone or in combination against urinary pathogens and probiotic organisms as well as their effect on biofilm formation and immune activity in infected cultured bladder epithelial cells. Results: Of the compounds tested, 1% citric acid was most consistently inhibitory to urinary pathogens as were combinations containing citric acid. Two combinations of compounds were tested and both showed antimicrobial activity when challenged with 1 × 105 bacteria/mL. The two combination products and D-mannose did not inhibit probiotic microorganisms and one composition increased the inhibitory potential of probiotic organisms. Results obtained with biofilm studies were variable, but probiotic biofilm was enhanced under some circumstances. Biofilms of some urinary pathogens were reduced by antimicrobial mixtures. A strong cytokine response was elicited when T24 bladder epithelial cells were infected for one hour with urinary pathogens and a modest reduction in cytokine response was recorded with some combinations of test compounds. Conclusion: Citric acid alone and mixtures of various compositions containing citric acid inhibited the growth and biofilm formation by 4 uropathogens. Probiotic organisms grew in the presence of mannose and citric acid-containing combinations. One of the combinations enhanced probiotic activity of Lactobacilli against uropathogens. When infecting T24 cell monolayers with uropathogens, potential modulation of inflammatory activity was demonstrated.