Correlation between the number of bacteria and bacterial PI <i>in vitro</i> and <i>in vivo</i>.

<p>BLI sensitivity was assessed using a CCD-based macroscopic detector to quantify the bacterial photon intensity (PI = photons/sec/cm²/steradian) for various numbers of bacteria (1.25×10⁵ to 2.0×10⁶ CFU per well). (A) <i>In vitro</i> study: the bacterial PI from colonies of bioluminescent MRSA was significantly correlated with the number of bacterial CFUs (<i>R</i>² = 0.9912). (B) <i>In vivo</i> study: various numbers of bacteria (1.25×10⁵–2.0×10⁶ CFU per inoculation) were inoculated into the SGM, and bioluminescence in the region of interest (ROI) was monitored by BLI. There was a significant correlation between the number of inoculated bacteria and the bacterial PI <i>in vivo</i> (<i>R</i>² = 0.9882).