Table 1.

Flea infection results with KIM6+ and KIM6+ΔyitA-yipB

Strain	CFU/mL in blood meal	CFU/infected fleaa			% Fleas infectedb			% Fleas blockedc
		Day 0	Day 7	Day 28	Day 0	Day 7	Day 28
KIM6+	1.04e7	3.91e3 ± 6.45e2	1.84e5 ± 3.51e4	3.79e5 ± 4.82e4	100.0	85.0	85.0	29.0
KIM6+ΔyitA-yipB	1.75e7	5.95e3 ± 1.03e3	2.61e5 ± 6.40e4	4.24e5 ± 6.86e4	100.0	75.0	80.0	33.0
KIM6+	5.20e7	1.66e4 ± 2.00e3	6.16e5 ± 1.21e5	4.99e5 ± 1.00e5	100.0	95.0	80.0	49.0
KIM6+ΔyitA-yipB	1.55e8	4.16e4 ± 3.82e3	5.30e5 ± 1.12e5	4.75e5 ± 1.13e5	100.0	80.0	75.0	51.0

a Mean ± standard error of CFU counts from 20 individual female fleas collected on the indicated day after infection.

b Percentage of 20 female fleas collected on the indicated day after infection from which Y. pestis CFU were recovered.

c Percentage of fleas that became blocked during the 28 days after infection.