Cranberry-derived proanthocyanidins prevent formation of Candida albicans biofilms in artificial urine through biofilm- and adherence-specific mechanisms

Section of Infectious Diseases, New Mexico Veterans Healthcare System, Albuquerque, NM, USA.
Journal of Antimicrobial Chemotherapy (Impact Factor: 5.31). 10/2013; 69(2). DOI: 10.1093/jac/dkt398
Source: PubMed


Candida albicans is a common cause of nosocomial urinary tract infections (UTIs) and is responsible for increased morbidity and healthcare costs. Moreover, the US Centers for Medicare & Medicaid Services no longer reimburse for hospital-acquired catheter-associated UTIs. Thus, development of specific approaches for the prevention of Candida urinary infections is needed. Cranberry juice-derived proanthocyanidins (PACs) have efficacy in the prevention of bacterial UTIs, partially due to anti-adherence properties, but there are limited data on their use for the prevention and/or treatment of Candida UTIs. Therefore, we sought to systematically assess the in vitro effect of cranberry-derived PACs on C. albicans biofilm formation in artificial urine.
C. albicans biofilms in artificial urine were coincubated with cranberry PACs at serially increasing concentrations and biofilm metabolic activity was assessed using the XTT assay in static microplate and silicone disc models.
Cranberry PAC concentrations of ≥16 mg/L significantly reduced biofilm formation in all C. albicans strains tested, with a paradoxical effect observed at high concentrations in two clinical isolates. Further, cranberry PACs were additive in combination with traditional antifungals. Cranberry PACs reduced C. albicans adherence to both polystyrene and silicone. Supplementation of the medium with iron reduced the efficacy of cranberry PACs against biofilms.
These findings indicate that cranberry PACs have excellent in vitro activity against C. albicans biofilm formation in artificial urine. We present preliminary evidence that cranberry PAC activity against C. albicans biofilm formation is due to anti-adherence properties and/or iron chelation.

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    • "Results of Feldman et al. (2012) were obtained studying only one strain of C. albicans . Rane et al. (2014) studied several strains of C. albicans and reported active concentrations close to those observed in our study; however, they reported that cranberry reduced biofilm formation of all tested strains contrary to what we observed, suggesting a strain-dependence of cranberry activity. In addition, our results demonstrated that the anti-adhesion activity of cranberry extract and PACs fractions was not limited to C. albicans but was also observed with emerging fungal pathogen C. glabrata. "
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