The Vibrio harveyi bioassay used routinely to detect AI-2 quorum sensing inhibition is confounded by inconsistent normalization across marine matrices.

The Vibrio harveyi autoinducer-2 (AI-2) bioassay is used routinely to screen for inhibition of the AI-2 quorum sensing system. The present study utilizes three well-described bacterial strains to demonstrate that inconsistent normalization across matrices undermines the assay's use in screening marine samples for AI-2 inhibition.