Standardized biofilm ratio: a comparative tool for crystal-violet microtiter plate assay testing in gram-negative bacteria.

Currently, assessment of bacterial biofilm formation using crystal-violet microtiter plate assay presents challenges in both method consistency and underlying biological rationale. This problem has limited comparison of results among researchers and standardized practical interpretation as a virulence factor. We propose a Standardized Biofilm Ratio (SBR) calculation model protocol for in vitro biofilm evaluation in Gram-negative bacteria.