Polymicrobial Biofilm Dynamics of Multidrug-Resistant Candida albicans and Ampicillin-Resistant Escherichia coli and Antimicrobial Inhibition by Aqueous Garlic Extract.

The polymicrobial biofilm of C. albicans with E. coli exhibits a dynamic interspecies interaction and is refractory to conventional antimicrobials. In this study, a high biofilm-forming multidrug-resistant strain of C. albicans overcomes inhibition by E. coli in a 24 h coculture. However, following treatment with whole Aqueous Garlic Extract (AGE), these individual biofilms of multidrug-resistant C. albicans M-207 and Ampicillin-resistant Escherichia coli ATCC 39936 and their polymicrobial biofilm were prevented, as evidenced by biochemical and structural characterization. This study advances the antimicrobial potential of AGE to inhibit drug-resistant C. albicans and bacterial-associated polymicrobial biofilms, suggesting the potential for effective combinatorial and synergistic antimicrobial designs with minimal side effects.

Candida albicans biofilm formation and growth optimization for functional studies using response surface methodology.

AIM: Optimization of Candida albicans growth and biofilm formation is essential for understanding the recalcitrance of this pathogen to advance functional analysis on hospital tools and material surfaces. Optimization and quantification of biofilm have always been a challenge using the conventional one variable at a time (OVAT) method. The present study uses central composite design-based response surface methodology for optimization of conditions to induce growth and biofilm formation in Candida albicans on polystyrene microtiter plates. METHODS AND RESULTS: Statistical software package, Stat Soft®, STASTICA version 12.6 was used for data analysis. The variables considered in the design matrix were media pH, temperature, incubation period, shaker speed and inoculum size. A four-pronged quantification approach with XTT assay (cell viability), crystal violet assay (biofilm), calcofluor white assay and wet/dry weight measurements (cell mass) was used to understand different aspects of biofilm formation. Cell viability and cell mass were inversely related; however, biofilm was independent of these two factors. The study also highlighted the fact that foetal bovine serum does not significantly contribute to cell adhesion and in turn in vitro biofilm formation in some of the cultures. CONCLUSIONS: A high-throughput optimization of C. albicans growth and biofilm formation on polystyrene microplate has been developed and validated. SIGNIFICANCE AND IMPACT OF STUDY: This is a first time approach to optimize the interaction of parameters for C. albicans biofilm formation using RSM. Heterogeneity in growth conditions for local strains of C. albicans clinical isolates was observed. This microtiter plate-based method can be used for future screening of therapeutics for the control of C. albicans.