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. 2016 Oct 17;84(11):3141–3151. doi: 10.1128/IAI.00430-16

TABLE 2.

Spirochetes lacking bb0318 have a 100-fold-attenuated infectious dose

Clone genotype No. of mice infecteda/no. analyzed with the following spirochete dose:
ID50 (90% CI)c
1 × 103 1 × 104 1 × 105 1 × 106 1 × 107
Wild type 0/6 1/6 3/6 N/A N/A 3.6 × 104 (7.9 × 102–1.6 × 106)
Δbb0318/pBSV2G N/A 0/6 0/6 1/6b 5/6 3.5 × 106 (1.0 × 106–1.2 × 107)
Δbb0318/pBSV2G bb0318 0/6 1/6 4/6 N/A N/A 4.8 × 104 (2.1 × 103–1.0 × 106)
a

Mouse infection was determined 3 weeks postinoculation by positive reisolation of spirochetes from the ear, bladder, and joint tissues unless otherwise noted. N/A, not applicable.

b

Positive reisolation of spirochetes from bladder and joint tissues only.

c

The 50% infectious dose (ID50) is the number of spirochetes required to infect 50% of the mice inoculated. The ID50 values and associated 90% confidence intervals (90% CI) were calculated using probit regression analysis (JMP, version 12.2.0; SAS Institute, Inc.).