Fig. 5

Kinetics of USA300 in the in vitro biofilm formation on stainless steel. Bioluminescent USA300 (USA300 LAC:lux) was inoculated in the flow chamber as described in Fig. 3, and the stainless-steel pins were harvested at the indicated time (n = 4). A Heat map images of the harvested pins in a microtiter plate during bioluminescent imaging (BLI exposure time 60 s, colour scale 1e5–1e6). B Quantification of the BLI signal (p/s/cm²/sr logarithmic scale) in the 1 cm² ROI is presented as the mean +/− SEM (*p < 0.05). C Representative SEM images of the pin are shown at 80x (left), and the ROIs containing biofilm (red box) are shown in the SEM at 5000x (right). Note that significant biofilm formation did not occur until the bacteria had adhered to the pin at 6 h. While fibril networks formed on top of the bacteria thereafter, this did not markedly increase the BLI signal from its peak at 6 h