Biofilm formation by the interaction of fungi (Candida tropicalis) with various bacteria

Biofilms are composed of more than one species and are often called polymicrobial biofilms, so research is needed on the formation of polymicrobial biofilms, especially between fungi and bacteria. This study aimed to analyze the total biomass and metabolic activity of biofilms formed from the interaction of fungi (Candida tropicalis) with various bacteria, including Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii. Bacterial and fungal cultures were suspended in tryptic soy broth (TSB) medium, and biofilm was cultivated in two 96-well microplates for 48 hours at 37°C. The crystal violet assay was used to detect the total biomass biofilm, and the tetrazolium salt (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, or MTT) assay was used to obtain the metabolic activity of biofilm with the optical density (OD) value using an ELISA reader. The results of this study obtained significant data from both parameters. The highest average value was found in the C. tropicalis treatment group (2,412 ± 0.825 on the biomass test results; 1,525 ± 0.473 on the metabolic activity test results), while the lowest was seen in the S. aureus treatment group (0.512 ± 0.224 in the biomass test results; 0.978 ± 0.349 in the metabolic activity test results). In conclusion, it was confirmed that biofilm biomass could be generated strongly in each treatment in the total biomass parameter, while metabolic activity data suggested that each treatment could carry out cell proliferation.