FIG. 1.

Schematic depiction of the experimental system used to track the penetration of antibiotics through the biofilms. The biofilm (A) was developed on a 25-mm-diameter microporous polycarbonate membrane (D) resting on agar culture medium. A 13-mm-diameter microporous polycarbonate membrane (C) was placed on top of the biofilm. A moistened concentration disk (B) was placed on top of the 13-mm-diameter membrane. The entire unit, components A through D, was transferred to antibiotic-containing agar (E) with sterile forceps.