Adaptation of the neutral bacterial comet assay to assess antimicrobial-mediated DNA double-strand breaks in Escherichia coli

► We adapted the bacterial neutral comet assay for use with soluble antimicrobials. ► The assay was employed to investigate the mechanism of action of an antibacterial clay mineral mixture. ► Longer comets and thus, higher DNA double-strand break levels, were detected in antibacterial clay leachate-exposed E. coli. ► Appropriate control reactions and nucleic acid stains for the assay were established.