CSP1 and Sepsis: However, in our recent in vivo imaging system (IVIS)-based live imaging study during pneumonic sepsis in CD-1 mice using a D39 reporter strain harboring a firefly luciferase transcriptionally fused to the late competence ssbB gene (D39-ssbB-luc) (Lin and Lau, 2019), D39 was able to enter the competent state naturally without the exogenously provided CSP1 (Lin et al., 2020).