Fig. 9.

Time course to represent the fluorescence change observed during $\mathrm{\beta }$-LEAF assays using second generation probe with S. aureus ATCC strains with known production of $\mathrm{\beta }$-lactamase. $\mathrm{\beta }$-LEAF assays were performed with the two ATCC S. aureus control strains, known $\mathrm{\beta }$-lactamase producer #1 – B-lac(+) and nonproducer #2 – B-lac(-). The bacteria were incubated with probe alone and probe+cefazolin as a test antibiotic, respectively, and fluorescence was monitored over 60 min, at 1-min intervals. The $y$-axis shows the fluorescence as RFUs and $x$-axis shows the time in minutes.