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Table 2 Quantitation of S. aureus genomic DNA (gDNA) by real time PCR

From: Multiple displacement amplification as an adjunct to PCR-based detection of Staphylococcus aureus in synovial fluid

MDA S. aur gDNA Probe Average Ct SEM (±)
N 100 ng proS 17.8 0.03
N 10 ng proS 22.1 0.05
N 1 ng proS 24.6 0.03
N 0.1 ng proS 27.7 0.06
N 0.01 ng proS 31.7 0.26
N 0 ng proS U U
(N) 0.01 ng proS 35.4 0.85
(Y) 0.01 ng proS 16.9 0.05
  1. Triplicate samples of isolated S. aureus genomic DNA were assayed by qPCR; the calculated average threshold critical cycle (Ct) values are provided, as is the standard error. Each sample concentration gave a highly reproducible result; the data shown are using the proS probe, but equivalent results were obtained using lysS. Pre-treatment of S. aureus gDNA by MDA resulted in a massive reduction in Ct, indicating a massive amplification of template. In MDA control lacking the DNA polyermase, Ct actually slightly increased, due to dilution of the starting material. 0 ng of gDNA (negative control) gave no detectable signal (Ct undetermined, represented as "U" above).