FIG. 1.
Quantitative detection of bacteria by RT-qPCR and by qPCR. E. coli ATCC 11775T (A), E. faecalis ATCC 19433T (B), S. aureus ATCC 12600T (C), C. perfringens JCM 1290T (D), and P. aeruginosa ATCC 10145T (E) were cultivated separately in BHI or MRS broth. RNA and DNA fractions were extracted from culture samples in the early stationary phase (18 h), and the bacterial counts were determined microscopically with DAPI staining. Based on the bacterial counts, 10-fold serial dilutions of RNA or DNA from 105 to 10−3 bacteria were assessed by RT-qPCR (○) and qPCR (•) assays. The CT values for triplicate samples obtained were plotted against the log10 number of bacterial cells subjected to each reaction.