Table 1. Bacteria and spore burden in the lungs of mice.

Inoculum	Average Retained Dosea	Time	Total Bacteria/Sporesb	P valuec
(spores/mouse)	(cfu±SEM)	(weeks)	(cfu×104/lung±SEM)	(vs. 2 weeks)
		2	37±6.5/20±5.0	-
1.3×107	(1.5±0.1)×106	4	2.3±0.4/1.6±0.4	<0.01/<0.05
		8	1.3±0.6/1.1±0.6	<0.01/<0.05
		2	41±9.7/39±9.2	-
1.1×108	(2.6±0.7)×107	4	9.2±2.3/4.4±1.3	<0.01/<0.01
		8	NDd	NDd

^aAverage retained dose was determined by harvesting the lungs 1 hour after intranasal inoculation and dilution plating the lung homogenates.

^bThe amounts of total bacteria and spores in the lung as described in the Figure 1 legend are expressed as the mean±SEM at 2, 4, or 8 weeks post-inoculation. Results are combined from two independent experiments.

^cStatistical analysis was performed using the two-tailed Student's t-test. *, p<0.05; **, p<0.01; compared to respective total bacteria and spore titers at 2 weeks.

^dNot determined.