TABLE 1.

In vitro activity of ceftazidime-avibactam and other agents against Gram-negative isolates from patients enrolled in the phase 3 clinical trial (all randomized patients)^a

Baseline pathogen(s)	Agent(s)	No. of pathogens tested	MIC datab
			Range (μg/ml)	MIC50 (μg/ml)	MIC90 (μg/ml)	%Sc
Enterobacteriaceae
All pathogens	Ceftazidime-avibactam	314	≤0.008–>256	0.25	1	98.7
	Ceftazidime	314	0.06–>64	64	>64	9.9
	Amikacin	314	0.25–>64	4	>64	86.6
	Ciprofloxacin	314	0.015–>4	>4	>4	10.8
	Colistin	314	0.12–>128	1	2	91.4d
	Gentamicin	314	≤0.12–>16	>16	>16	40.1
	Imipenem	314	0.06–64	0.12	0.5	93.9
	Meropenem	314	0.015–>8	0.03	0.25	95.9
	Piperacillin-tazobactam	314	0.12–>128	16	>128	52.5
	Tigecycline	314	0.12–8	0.5	2	81.8e
	Trimethoprim-sulfamethoxazole	314	≤0.25–>8	>8	>8	34.7
Enterobacter cloacae	Ceftazidime-avibactam	17	0.25–>256	0.5	4	94.1
	Ceftazidime	17	16–>64	64	>64	0
	Amikacin	17	1–>64	2	>64	76.5
	Ciprofloxacin	17	0.015–>4	>4	>4	41.2
	Colistin	17	0.5–>128	1	2	94.1
	Gentamicin	17	0.25–>16	>16	>16	41.2
	Imipenem	17	0.12–16	0.25	0.5	94.1
	Meropenem	17	0.03–>8	0.06	0.25	94.1
	Piperacillin-tazobactam	17	2–>128	128	>128	23.5
	Tigecycline	17	0.25–8	1	4	58.8
	Trimethoprim-sulfamethoxazole	17	≤0.25–>8	≤0.25	>8	70.6
Escherichia coli	Ceftazidime-avibactam	139	≤0.008–8	0.12	1	100
	Ceftazidime	139	0.12–>64	32	>64	13.7
	Amikacin	139	0.5–>64	4	8	95.7
	Ciprofloxacin	139	0.015–>4	>4	>4	7.2
	Colistin	139	0.12–4	1	2	97.1
	Gentamicin	139	0.25–>16	16	>16	48.2
	Imipenem	139	0.06–1	0.12	0.25	100
	Meropenem	139	0.015–1	0.03	0.06	100
	Piperacillin-tazobactam	139	1–>128	8	>128	75.5
	Tigecycline	139	0.12–1	0.25	0.5	100
	Trimethoprim-sulfamethoxazole	139	≤0.25–>8	>8	>8	62.6
Klebsiella pneumoniae	Ceftazidime-avibactam	131	0.06–>256	0.5	1	98.5
	Ceftazidime	131	0.06–>64	>64	>64	5.3
	Amikacin	131	0.25–>64	4	>64	81.0
	Ciprofloxacin	131	0.03–>4	>4	>4	3.8
	Colistin	131	0.25–64	1	2	94.0
	Gentamicin	131	≤0.12–>16	>16	>16	32.1
	Imipenem	131	0.06–64	0.12	1	90.8
	Meropenem	131	0.015–>8	0.06	1	91.6
	Piperacillin-tazobactam	131	1–>128	128	>128	31.3
	Tigecycline	131	0.25–8	1	2	74.0
	Trimethoprim-sulfamethoxazole	131	≤0.25–>8	>8	>8	27.5
Other Enterobacteriaceaef	Ceftazidime-avibactam	27	0.03–256	0.5	2	96.3
	Ceftazidime	27	0.12–>64	64	>64	18.5
	Amikacin	27	0.5–>64	4	>64	74.1
	Ciprofloxacin	27	0.015–>4	>4	>4	18.5
	Colistin	27	0.5–>128	>128	>128	48.1d
	Gentamicin	27	0.25–>16	>16	>16	37.0
	Imipenem	27	0.12–16	0.5	4	77.8
	Meropenem	27	0.015–>8	0.06	0.25	96.3
	Piperacillin-tazobactam	27	0.12–>128	16	>128	55.6
	Tigecycline	27	0.25–8	2	8	40.7e
	Trimethoprim-sulfamethoxazole	27	≤0.25–>8	>8	>8	33.3
Nonfermenters
Pseudomonas aeruginosa	Ceftazidime-avibactam	27	1–256	8	64	55.6
	Ceftazidime	27	1–>64	64	>64	29.6
	Amikacin	27	0.5–>64	16	64	55.6
	Cefepime	27	1–>16	16	>16	29.6
	Ciprofloxacin	27	0.06–>4	>4	>4	18.5
	Colistin	27	0.5–4	2	4	100
	Gentamicin	27	1–>16	>16	>16	33.3
	Imipenem	27	0.5–>64	2	16	55.6
	Meropenem	27	0.06–>8	1	>8	59.3
	Piperacillin-tazobactam	27	0.5–>128	64	>128	33.3

^aMIC₅₀ and MIC₉₀ values were not calculated for pathogens with <10 patients. A patient can have more than one pathogen. Multiple isolates of the same species from the same patient are counted only once using the isolate with the highest MIC to the study drug received. For bacteremic patients, multiple isolates of the same species from the same patient are counted only once using the isolate with the highest MIC to the study drug received across the culture source (urine or blood).

^bThe total number of patients in the treatment group was 333.

^c%S, percent susceptible.

^dThe %S is based on EUCAST breakpoints and includes species with intrinsic resistance to colistin.

^eThe %S is based on EUCAST breakpoints and includes species with reduced susceptibility to tigecycline.

^fOther Enterobacteriaceae include Citrobacter freundii (7), Enterobacter aerogenes (2), Klebsiella oxytoca (1), Morganella morganii (15), Proteus mirabilis (16), Providencia rettgeri (15), Providencia stuartii (15), Raoultella terrigena (15), and Serratia marcescens (1).