TABLE 2.

Vaccinated or naïve C57BL/6 mice are similarly protected after receiving 7 days of co-trimoxazole initiated within 45 h after exposure to aerosolized B. pseudomallei. Only vaccinated mice survived 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 70 post challenge	Day 70 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 9 h	100%	<0.0001	100%	<0.0001	10/10	<0.0001
PBS + co-trimoxazole 21 h	100%	<0.0001	90%	0.0001	6/9e	0.0001
PBS + co-trimoxazole 45 h	70%	0.0031	70%	0.0031	6/7e	0.0002
PBS + co-trimoxazole 69 h	0%	NSd	0%	NS	n/a	NS
668 ΔilvI	20%	NS	20%	NS	1/2e	<0.0001
668 ΔilvI + co-trimoxazole 9 h	100%	0.0007	90%	0.0055	10/10	0.0007
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	100%	0.0007	7/10e	0.0003
668 ΔilvI + co-trimoxazole 69 h	90%	0.0055	80%	0.0230	6/8e	0.0017
AhpC + Hcp1 + conjugatef	56%	0.0325	22%	NS	2/2	<0.0001
AhpC + Hcp1 + conjugate + co-trimoxazole 9 hf	100%	0.0294	100%	0.0023	9/9	0.0008
AhpC + Hcp1 + conjugate + co-trimoxazole 21 hg	100%	0.0294	100%	0.0023	8/8	0.0015
AhpC + Hcp1 + conjugate + co-trimoxazole 45 hf	100%	0.0294	100%	0.0023	8/9e	0.0008
AhpC + Hcp1 + conjugate + co-trimoxazole 69 hf	100%	0.0294	89%	0.0152	8/9e	0.0020
Hcp1 + conjugate	60%	0.0108	20%	NS	2/2	<0.0001
Hcp1 + conjugate + co-trimoxazole 9 hf	100%	NS	100%	0.0007	9/9	0.0005
Hcp1 + conjugate + co-trimoxazole 21 h	90%	NS	90%	0.0055	9/9	0.0031
Hcp1 + conjugate + co-trimoxazole 45 h	100%	NS	100%	0.0007	9/10e	0.0003
Hcp1 + conjugate + co-trimoxazole 69 hf	100%	NS	100%	0.0007	8/9e	0.0005

Only vaccinated mice survived the infection when co-trimoxazole was initiated at 69 h post exposure.

^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 2.45 × 10³ CFU (+/− 4.33 × 10² CFU) of aerosolized B. pseudomallei K96243 on day 35 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.

^fN = 9.

^gN = 8.