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Candida albicans often form polymicrobial biofilms along with pathogenic microbes. Silver nanoparticles (AgNPs) were well known to have strong antimicrobial activity. However, their effect on polymicrobial biofilms and the mechanism has never been reported. This study aimed to synthesize AgNPs and study their effects on polymicrobial biofilm represented by C. albicans–E. coli biofilm. Polymicrobial biofilms, formed by clinical isolates of C. albicans and E. coli, were developed from the standardized suspensions of each strain by culturing flat-bottom 96-well microtiter plates for 48 h, then treated with AgNPs. Cell viability was assessed using the tetrazolium salt reduction assay; the extent of biofilm formation was measured by crystal violet staining. AgNPs reduced the polymicrobial biofilm in two ways: by degrading the extracellular matrix and killing both C. albicans and E. coli. The results showed AgNPs is a potential new approach for developing potent anti-biofilms.

Background and Aim: Candida albicans is the most prevalent human fungal pathogen. In biofilms, C. albicans becomes more resistant to antifungal agents because of the production of an extracellular matrix (ECM) that protects the yeast cells. This study aimed to determine the effects of hydrolase enzymes and the Bgl2 ligand on monomicrobial and polymicrobial biofilms. Materials and Methods: Biofilm induction in rats was carried out using streptomycin (25 mg/kg) and gentamicin (7.5 mg/kg) administered orally once per day for 5 days. Rats were injected subcutaneously with cortisone acetate (225 mg/kg) as an immunosuppressant on day 5. In addition, rats were orally administered C. albicans for the single microbial model and a combination of C. albicans with Escherichia coli for the polymicrobial model. Following the biofilm production, the groups were treated with glucosamine (8.57 mg/kg body weight) and Achatina fulica hydrolases (1.5 mL) orally for 2 weeks. The reduction of the biofilm was measured using confocal laser scanning microscopy (CLSM). Data were analyzed using a t-test, with a significance value of 95%. Results: CLSM images revealed a strong association between C. albicans and E. coli in the polymicrobial biofilm. On the contrary, the combination treatment using glucosamine and A. fulica hydrolases reduced the ECM of the single microbial biofilm (53.58%). However, treatment effectiveness against the matrix (19.17%) was reduced in the polymicrobial model. Conclusion: There is a strong association between C. albicans and E. coli in the formation of polymicrobial biofilms. The combination of glucosamine and the A. fulica enzyme can reduce the single microbial biofilm ECM; however, it is ineffective in the polymicrobial model.