TABLE 1.

Activity of ceftazidime-avibactam and comparator antimicrobial agents when tested against Pseudomonas aeruginosa isolates from U.S. medical centers (2012 to 2015)^d

Isolate group (n) and antimicrobial agent(s)	MIC50 (mg/liter)	MIC90 (mg/liter)	CLSIa			EUCASTb
			% S	% I	% R	% S	% I	% R
All isolates (7,452)
Ceftazidime-avibactam	2	4	97.0		3.0c	97.0		3.0
Ceftazidime	2	32	84.3	4.0	11.7	84.3		15.7
Cefepime	2	16	85.4	8.4	6.2	85.4		14.6
Piperacillin-tazobactam	4	>64	80.5	9.1	10.3	80.5		19.5
Meropenem	0.5	8	82.0	5.9	12.1	82.0	11.9	6.2
Ciprofloxacin	0.12	>4	77.5	5.3	17.2	71.8	5.7	22.5
Levofloxacin	0.5	>4	74.9	6.6	18.5	66.0	8.9	25.1
Gentamicin	≤1	8	88.3	3.7	8.1	88.3		11.7
Amikacin	2	8	97.0	1.2	1.8	93.0	4.0	3.0
Colistin	1	2	99.4	0.6	0.1	99.9		0.1
MDR isolates (1,151)
Ceftazidime-avibactam	4	16	82.1		17.9c	82.1		17.9
Ceftazidime	32	>32	27.6	16.0	56.4	27.6		72.4
Cefepime	16	>16	26.5	39.5	34.0	26.5		73.5
Piperacillin-tazobactam	>64	>64	15.5	34.0	50.6	15.5		84.5
Meropenem	8	>8	21.4	18.1	60.6	21.4	44.4	34.2
Ciprofloxacin	>4	>4	21.3	12.3	66.5	12.4	8.9	78.7
Levofloxacin	>4	>4	14.8	14.6	70.6	8.4	6.3	85.2
Gentamicin	4	>8	51.1	10.3	38.7	51.1		48.9
Amikacin	8	32	87.1	5.0	8.0	74.5	12.6	12.9
Colistin	1	2	99.1	0.6	0.3	99.7		0.3
XDR isolates (698)
Ceftazidime-avibactam	8	32	75.8		24.2c	75.8		24.2
Ceftazidime	32	>32	18.9	16.0	65.0	18.9		81.1
Cefepime	16	>16	14.3	42.0	43.7	14.3		85.7
Piperacillin-tazobactam	>64	>64	5.7	34.4	59.9	5.7		94.3
Meropenem	8	>8	7.6	17.6	74.8	7.6	46.3	46.1
Ciprofloxacin	>4	>4	10.2	12.2	77.7	3.3	6.9	89.8
Levofloxacin	>4	>4	4.2	14.2	81.7	2.1	2.0	95.8
Gentamicin	>8	>8	38.1	11.5	50.4	38.1		61.9
Amikacin	8	>32	83.2	6.2	10.6	68.1	15.2	16.8
Colistin	1	2	99.1	0.6	0.3	99.7		0.3

^aCriteria as published by CLSI (18).

^bCriteria as published by EUCAST (20).

^cBreakpoints from FDA package insert (10).

^dAbbreviations: MDR, multidrug resistant; XDR, extensively drug resistant (12); S, susceptible; I, intermediate; R, resistant.