TABLE 1.

Vaccinated or naïve C57BL/6 mice are similarly protected after receiving 21 days of co-trimoxazole initiated within 45 h after exposure to aerosolized B. pseudomallei. Vaccinated mice were more likely to survive than naive mice when co-trimoxazole was initiated 69 h post-exposure.

Vaccination status and treatment groupsa	% Survival through day 30 post challenge	Day 30 survival P-valueb	% Survival through day 82 post challenge	Day 82 Survival P-valueb	Ratio of Sterile survivors/Total Survivorsc	TTM P-valueb
PBS	0%	n/a	0%	n/a	n/a	n/a
PBS + co-trimoxazole 21 h	100%	<0.0001	90%	<0.0001	9/9	<0.0001
PBS + co-trimoxazole 45 h	100%	<0.0001	100%	<0.0001	8/10e	<0.0001
PBS + co-trimoxazole 69 h	40%	NSd	30%	NS	2/3e	NS
668 ΔilvI	20%	NS	20%	NS	0/2e	0.0002
668 ΔilvI + co-trimoxazole 21 h	100%	0.0007	100%	0.0007	10/10	0.0003
668 ΔilvI + co-trimoxazole 45 h	100%	0.0007	90%	0.0007	9/9	0.0008
668 ΔilvI + co-trimoxazole 69 h	90%	0.0055	90%	0.0055	9/9	0.0024
AhpC + Hcp1 + conjugate	60%	0.0108	60%	0.0108	5/6e	<0.0001
AhpC + Hcp1 + conjugate + co-trimoxazole 21 h	100%	NS	100%	NS	10/10	0.0291
AhpC + Hcp1 + conjugate + co-trimoxazole 45 h	100%	NS	100%	NS	10/10	0.0291
AhpC + Hcp1 + conjugate + co-trimoxazole 69 h	100%	NS	90%	NS	9/9	NS

^aMice were vaccinated as described in Section “Materials and methods.” If co-trimoxazole was provided it was initiated at the time-point after exposure to approximately 2.86 × 10³ CFU (+/− 3.95 × 10² CFU) of aerosolized B. pseudomallei K96243 on day 29 post-last vaccination.

^bStatistical comparison to respective control group without co-trimoxazole or in the case of vaccines only to the PBS alone group. P-values indicate the result of a Log-rank or Fisher exact test for the survival and TTM, respectively.

^cSurvivors were determined to be free of B. pseudomallei CFU in lungs and spleens and there was no visible pyogranuloma formation noted at gross necropsy.

^dNS, not significant.

^eSee Supplementary Table 2 for bacterial burden data for each mouse shown to retain B. pseudomallei. Limit of detection for tissue homogenates is 5 CFU/organ.