Biofilm formation efficiency by Candida species isolated from gastric mucosa of intragastric balloon patient under extremely low pH.

This study characterized biofilms formed by Candida albicans and C. tropicalis isolated from the gastric mucosa biopsies of an intragastric balloon (IGB) patient user. Both were cultivated to form single and mixed artificial biofilms at pH 2.5 and 5.5 for 24 and 48 h. The biofilms were assessed for biochemical, metabolic, and ultrastructural properties. Yeast counts in monospecies C. albicans and C. tropicalis biofilms were higher than their respective levels in mixed biofilms across both pH values. Single C. tropicalis biofilms exhibited greater metabolic activity at both time points than C. albicans and mixed biofilms. While there were no notable pH or time-dependent differences in C. albicans and C. tropicalis monospecies biofilm formation, mixed biofilms displayed significantly higher biomass at pH 2.5. Ct also demonstrated pronounced filamentation within 24 h at pH 5.5. Scanning electron microscopy revealed cellular damage in mixed biofilms at pH 2.5; although, the biofilm structure was well developed within 24-48 h. Our findings indicate that yeasts isolated from IGB patients can form mono and polymicrobial biofilms under harsh conditions, with both species demonstrating biofilm viability at pH 2.5. Notably, C. tropicalis exhibited increased competitiveness in mixed biofilms under these conditions.