Quantification of Streptococcus salivarius using the digital polymerase chain reaction as a liver fibrosis marker

Figure 2 Comparison of bacterial load measured using digital PCR and bacterial titremeasured using plaque assay. A: Profiles of digital PCR (dPCR) assays targeting the tnpA on bacterial suspensions of Streptococcus salivarius (S. salivarius) strain; B: Profiles of dPCR assays targeting 16S rRNA in S. salivarius bacterial suspensions. Fluorescence amplitude plot of dPCR assays on bacterial suspensions at 5-fold diluted concentrations from 2.00 × 10⁶ to 1.28 × 10² colony forming unit/mL. The blue line represents a threshold to distinguish between positive and negative droplets based on the fluorescence signal. Droplets with a fluorescence signal above this threshold are classified as positive, indicating the presence of amplification. dPCR: Digital PCR; CV: Coefficients of variability; CFU: Colony forming unit.