Fig 5.

Detection of spirochete burdens in needle-infected SCID mice by qRT-PCR. Groups of three mice were needle inoculated with 10⁵ cells of the wild-type, cheA₂^mut, and cheA₂^com strains. Infected animals were sacrificed at 24, 48, and 72 h. Skin samples from areas around the inoculation sites were collected and subjected to qRT-PCR. The bacterial burdens in these samples were measured by determining the number of copies of flaB mRNA compared to the number of copies of mouse β-actin transcript as previously documented (41, 66). The data are expressed as the means of relative levels of flaB transcript ± SEM for three independent experiments. At 72 h, the flaB mRNA was undetectable in the skin tissues infected by cheA₂^mut. *, significant difference (P < 0.01). Bb, B. burgdorferi.