Table 1.
Strains used in this study and MICs of ceftaroline.
Table 2.
Primer used for qRT-PCR.
Fig 1.
The bacterial cell morphology of MRSA treated with ceftaroline.
TEM, A-D; SEM, (A´-D´). (A-A´) strain 06/1483 after exposure to 1/2 MIC of ceftaroline. (C-C´) strain 06/1483 without antibiotic. (B-B´) strain 05/3291 after exposure to 1/2 MIC of ceftaroline. (D-D´) strain 05/3291 without antibiotic. Biofilms of strains 06/1483 (E) and 05/3291 (F) exposed to 1/2 MIC of ceftaroline. Original Magnifications: (A) ×80.000; (A´) ×15.000; (B) ×50.000; (B´) ×15.000; (C) ×40.000; (C´) ×20.000; (D) ×60.000; (D´) ×20.000. (E,F) ×15.000. Scale bars, (A-D´) 1μm.
Fig 2.
Effects of ceftaroline on biofilm formation.
Biofilm formation by MRSA in presence of ceftaroline, in 24-well polystyrene plates after 48 h, assessed by crystal violet staining. Each bar indicates the mean values ± SE from four independent experiments. Strains 06/1483, 05/2369, 05/3291 were tested. ATCC 29213 was also included. 0, no antibiotic added (control). X-axis represents ceftaroline concentrations (respect to the MIC). *Indicates significant differences between the concentration tested and control.
Fig 3.
Effects of ceftaroline on biofilm disruption.
Disruption of preformed biofilms by ceftaroline after growth in 24-well polystyrene plates and assessed by crystal violet staining. Each bacterial strain was tested in duplicate, and bars indicate the mean values ± SE from four independent experiments. Strains 06/1483, 05/2369, 05/3291 and ATCC 29213 were tested. 0, no antibiotic added (control). Ceftaroline concentrations (μg/ml) are indicated on the X-axis. *Indicates significant differences between the concentration tested and control. Φ Indicates the MIC for each strain.
Fig 4.
CLSM of biofilms formed by MRSA strains in presence of ceftaroline.
Confocal Laser Scanning Microscopic images of strains 06/1483, 05/2369, and 05/3291 after growth on uncoated 4-well chamber slides and stained with the LIVE/DEAD viability kit. Live cells are stained green with Syto 9 dye and dead cells are stained red with propidium iodide. MIC and sub-MICs are indicated. Original magnification ×200.
Fig 5.
(A) coloured proteic matrix of strain 05/3291 exposed to different sub-MICs of ceftaroline. No Ab, without ceftaroline. (B) Biofilm composition of strains 06/1483 and 05/3291. CLSM of Film Tracer (purple) and NucBlue (blue) staining of strains 06/1483 (left), and 05/3291 (right) without ceftaroline. Original magnification: ×200. Scale bars, 10μm.
Table 3.
Gene Expression of S. aureus genes in biofilms.