In vitro anti-biofilm efficacy of sanguinarine against carbapenem-resistant Serratia marcescens

Sanguinarine, a plant-derived benzophenanthridine alkaloid, was studied in terms of its anti-biofilm effects against carbapenem-resistant Serratia marcescens (CRSM). Minimum inhibitory concentrations (MICs) and cell membrane integrity were measured to investigate the antimicrobial mechanism of sanguinarine. Additionally, the extent of biofilm formation by CRSM exposed to sanguinarine was measured by crystal violet staining and visualized via field emission scanning electron microscopy and confocal laser scanning microscopy. Sanguinarine displayed moderate activity against CRSM, with a MIC90 of 32 μg ml−1. Moreover, cell membrane integrity was severely disrupted by sanguinarine at 64 μg ml−1, and biofilm formation was sharply inhibited at 32 μg ml−1. The minimum biofilm eradication concentration was 512 μg ml−1 against mature CRSM biofilms. The overall results suggest that sanguinarine is a potential anti-biofilm agent that can be explored to treat CRSM infections.