TABLE 3.

Magnitudes of avibactam exposures associated with stasis and bacterial killing of ceftazidime-resistant P. aeruginosa in the neutropenic mouse lung infection model in the background of q2h dosing of ceftazidime^a

Strainb	MIC (mg/liter)		Codosing expte	Avibactam %fT>1 mg/literf associated with:
	CAZc	CAZ-AVId		Stasis	1-log10 kill	2-log10 kill
5	128	8	q2h	19.4	20.6	Not reported
7	64	4	q2h	21.4	22.4	Not reported
11	128	16	q2h	19.7	34.9	55.3
			q8h	20.9	21.6	22.5
18	32	2	q2h	23.5	26.7	31.8
			q8h	16.1	17.8	20.2
Mean				20.2	24.0	32.4
SD				2.5	6.1	16

^aData are from Berkhout et al. (44).

^bResistance summaries for the strains used in this experiment are as follows. Strain 5: nitrocefinase activity, ++++; AmpC transcript, overexpressed; β-lactamase genotype, bla_AmpC; class A⁻, class B⁻; strain 7: nitrocefinase activity, +++; AmpC transcript, overexpressed; β-lactamase genotype, bla_AmpC; class A⁻, class B⁻; strain 11: OprD⁻, AmpC^con, class A⁻, class B⁻; strain 18: OprD⁻, AmpC_ind?, class A⁻, class B⁻; strain 19: OprD⁻, AmpC^con, class A⁻, class B⁻.

^cCAZ, ceftazidime.

^dAVI, avibactam.

^eq2h, ceftazidime and avibactam were dosed together at every administration; q8h, ceftazidime was dosed q2h but avibactam was codosed at 0, 8, and 16 h from the initiation of dosing.

^fTimes are expressed as percentages of the dosing interval.