Table 3. p15a plasmid loss with no selection detected in spleens recovered from moribund mice.

Mouse	Total CFUa (from spleen)	AmpS CFU	Plasmid Lossb
1- pdapA	100	5	5%
2- pdapA	100	2	2%
3- pdapA	80	3	3.75%
Combined	280	10	3.5%
1- pACYC-177	100	1	1%
2- pACYC-177	60	1	1.66%
3- pACYC-177	97	1	1.03%
Combined	257	3	1.17%

a: CFU: Colony forming units of Y. pestis KIM D27.

b: Amp^s/total CFU×100.