A simple and inexpensive device for biofilm analysis

The Calgary Biofilm Device (CBD) has been described as a technology for the rapid and reproducible assay of biofilm susceptibilities to antibiotics. In this study a simple and inexpensive alternative to the CBD was developed from polypropylene (PP) microcentrifuge tubes and pipette tip boxes. The utility of the device was demonstrated using Candida glabrata, a yeast that can develop antimicrobial-resistant biofilm communities. Biofilms of C. glabrata were formed on the outside surface of microcentrifuge tubes and examined by quantitative analysis and scanning electron microscopy. Growth of three C. glabrata strains, including a clinical isolate, demonstrated that biofilms could be formed on the microcentrifuge tubes. After 24 h incubation the three C. glabrata strains produced biofilms that were recovered into cell suspension and quantified. The method was found to produce uniform and reproducible results with no significant differences between biofilms formed on PP tubes incubated in various compartments of the device. In addition, the difference between maximum and minimum counts for each strain was comparable to those which have been reported for the CBD device.