TABLE 5.

Proportion of quinupristin-dalfopristin-resistant subpopulations (at 8 × original MIC) for VREF 12311 and VREF 12366 in the in vitro pharmacodynamic models

Time (h)	VREF 12311			VREF 12366
	Q/D q8ha,b	Q/D q8h plus doxycycline	Q/D high-dose continuous infusion	Q/D q8hb	Q/D q8h plus doxycycline	Q/D high-dose continuous infusion
0	<1 × 10−8.6	<1 × 10−8.6	<1 × 10−8.7	<1 × 10−8.6	<1 × 10−9.1	<1 × 10−8.7
8	2.6 × 10−8	<1 × 10−7.3	<1 × 10−6.8	2.2 × 10−7	<1 × 10−8.9	<1 × 10−8.5
24	8.5 × 10−7	<1 × 10−7	<1 × 10−6.2	1.8 × 10−4	<1 × 10−8.8	<1 × 10−8.3
48	6.3 × 10−5	<1 × 10−6.8	<1 × 10−5.9	3.5 × 10−4	<1 × 10−8.6	<1 × 10−8.1
72	2.0 × 10−4	<1 × 10−7	<1 × 10−6.2	3.1 × 10−4	<1 × 10−8.4	<1 × 10−8.2
96	4.4 × 10−4	3.4 × 10−7	<1 × 10−5.9	3.8 × 10−4	<1 × 10−7.9	<1 × 10−8.0

^aQ/D q8h, quinupristin-dalfopristin every 8 h. 

^bProportions of resistance for the low-dose continuous infusion were similar to the every-8-h regimen.