TABLE 2.

Effect of DNA extraction methods on the quantitation of R. rickettsii by SQ-PCR

SampleNo. of rOmpA copies per μl of DNA template by indicated extraction procedurea
BoilingBoiling plus ChelexDNeasy kit
Infected Vero cells1.81 × 104 ± 0.32 × 104b3.79 × 104 ± 1.75 × 104b6.11 × 105 ± 0.43 × 105
Renografin gradient density-purified rickettsiae4.52 × 104 ± 0.84 × 104b2.96 × 105 ± 0.11 × 105b4.22 × 105 ± 0.35 × 105
  • a The data are given as means±standard errors of the means for three independent preparations, each assayed in triplicate.

  • b P < 0.05 compared to DNeasy extraction.