Persistence of ΔmotB mutant spirochetes in nymphal ticks before and after a blood meala

Nymph artificially infected with B. burgdorferi cloneNo. of spirochete-infected nymphs/total no. tested (% positive)
WT15/15 (100)15/15 (100)
ΔmotB15/15 (100)3/35 (8.6)
motBcom14/15 (93)15/15 (100)
  • a Unfed and fed nymphs infected by immersion were squashed individually on day 7 postrepletion for DNA isolation. Infection efficiency of the ticks by B. burgdorferi (% positive) was determined by flaB gene-specific PCR. A representative result from two independent assays is shown.