FIG 2 .

BODIPY-labeled DAP (BDP-DAP) staining of representative cells from E. faecalis S613 derivatives at increasing concentrations of the fluorescent antibiotic. The images for each BDP-DAP concentration (from 2 to 32 μg/ml) and strain show bacterial cells captured by fluorescence (top image) and phase-contrast (bottom image) microscopy (bars, 1 µm). (a) E. faecalis S613∆_liaF177 is a derivative of strain S613 carrying a mutated liaF belonging to E. faecalis R712 (daptomycin resistant). (b) S613∆_{liaF177gdpD170} is a derivative of S613 carrying both liaF and gdpD alleles from strain R712. (c) S613∆_{liaF177gdpD170cls61} carries mutated liaF, gdpD, and cls alleles from R712. Introduction of the three mutated alleles prevents BDP-DAP interaction with the septum up to concentrations of 16 µg/ml of BDP-DAP. Additional images selected from different microscopic fields are shown in Fig. S3 in the supplemental material. Arrows indicate visualization of septum in a linear pattern.