Mouse infectivity of lp54 deletion mutants by needle inoculation

B. burgdorferi strainNo. of infected mice/no. of mice injected with 5 × 103 spirochetesaNo. of tissue reisolates/no. of injected mice (ear, bladder, joint)bNo. of spirochetes/larval tick (mouse 1; mouse 2)c
A33/43/4, 3/4, 3/42,500; 933
A3ΔA1-74/44/4, 4/4, 4/427,332; 866
A3ΔA7-144/44/4, 4/4, 4/46,333; 4
  • a Number of infected mice/number of mice injected with 5 × 103 spirochetes (4 × 103 spirochetes intraperitoneally and 1 × 103 spirochetes subcutaneously). Seroconversion was determined by immunoblot analysis with B. burgdorferi lysate 3 weeks postinoculation.

  • b Number of tissue reisolates/number of injected mice, for ear, bladder, and joint at 5 weeks postinoculation. All three tissues from infected mice were positive.

  • c Larval ticks were fed to repletion on two seropositive mice for each strain. Ten days postfeeding, three fed larvae from each mouse were pooled, crushed, and plated to determine the number of viable spirochetes. The average number of spirochetes per tick was calculated from the total number of colonies obtained per pool of three larvae for each mouse. Mean numbers of spirochetes per tick for the A3ΔA1-7 and A3ΔA7-14 mutants were not significantly different from those of the wild type (A3) as determined by a two-tailed, unpaired t test (P = 0.3 and P = 0.7, respectively), performed by use of GraphPad Prism 5 software.