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

Table 4 qPCR assay of purified S. aureus and human DNA (hDNA) mix, with and without MDA pre-treatment

Sample	Probe	MDA -	MDA +
0.01 ng S. aur + 100 ng hDNA	proS	U	+* (10/12)
0.01 ng S. aur + 10 ng hDNA	proS	U	+ (12/12)
0.01 ng S. aur + 1 ng hDNA	proS	U	+ (12/12)
0.01 ng S. aur + 0 ng hDNA	proS	U	+ (12/12)

Ct values were undetermined (U) for S. aureus DNA without MDA pre-treatment. In contrast, "+" indicates the successful detection of target template, demonstrating that MDA had successfully increased the S. aureus component to the level of detection; the numbers at right in parentheses represent the number of successful amplification attempts/number of total attempts. When 100 ng of human genomic DNA were used, in 2 out of 12 attempts no signal detection was observed although results were positive for the majority of trials, thus prompting a "+*" notation, with the possibility that this amount of excess background DNA may become partly inhibitory to the MDA.

ISSN: 1756-0500