Fig. 1

Characterization of calibrated inocula of Staphylococcus aureus biofilm and planktonic cultures. a and b SEM micrographs of S. aureus LYO-S2 planktonic (a) and 24 h biofilm (b) inocula after passing through the 34G needle used for micro-injections. Red arrows in panel B indicate the biofilm extracellular matrix. Scale bar: 5 μm. c and d Fluorescence microscopy images of S. aureus biofilm (c) and planktonic (d) cultures stained with the green live cell fluorescent label SYTO9 and incubated with CDy11 red fluorescent probe. Scale bar: 50 μm