Abstract: A method of treatment of a marine surface to improve the resistance of the surface to fouling from a marine organism, the method comprising treatment of a surface prone to fouling from a marine organism with a composition comprising a lactam, wherein the composition comprises from 0.0005 to 5 wt.

Abstract: Susceptibility of sessile microorganisms to antimicrobial agents is tested with a method comprising growing the microorganisms on a support to form a biofilm, contacting the biofilm with a metabolic substrate having a chromogenic and/or fluorogenic moiety to continue a base-line metabolic activity of the biofilm, contacting the biofilm with one or more antimicrobial agents, determining an experimental metabolic activity of the biofilm by measuring a signal from the metabolic substrate, and comparing the base-line metabolic activity with the experimental activity. The biofilm may be grown in a device comprising a plurality of wells, each well having a planar bottom and at least on wall, a plurality of supports comprising discs for growing the biofilm, each support disposed within a well perpendicular to the planar bottom, and at least one cover that fittably seals the top of each well.