Table 1.

MIC₅₀, MIC₉₀, MIC range, and percent susceptible for ceftazidime–avibactam, ceftazidime, ceftriaxone, and cefepime against Gram-negative aerobic and facultative pathogens22,23,25,26,28–30,32–35

Organism	Ceftazidime–avibactam			Ceftazidime			Ceftriaxone			Cefepime
	MIC50/90	MIC range	%S	MIC50/90	MIC range	%S	MIC50/90	MIC range	%S	MIC50/90	MIC range	%S
Citrobacter freundii	0.125/0.5	≤0.06–2	100	0.5/>32	≤0.25–>32	78.2	≤0.25/32	≤0.25–>64	85.3	≤0.25/≤0.25	≤0.25–1	100
Enterobacter aerogenes	0.25/0.5	≤0.06–16	98.5	0.5/>32	≤0.25–>32	76.9	≤0.25/>64	≤0.25–>64	72.3	≤0.25/≤0.25	≤0.25–1	98.9
Enterobacter cloacae	0.25/1	≤0.06–16	99.5	0.5/>32	≤0.25–>32	78.7	≤0.25/>64	≤0.25–>64	73.8	≤0.25/2	≤0.25–32	99.4
Escherichia coli	0.12/0.25	≤0.06–4	100	≤0.25/1	≤0.25–>32	94.9	≤0.25/≤0.25	≤0.25–>64	93	≤0.25/≤0.25	≤0.25–>64	97.6
ESBL-producing	0.12/0.25	≤0.06–1	100	16/>32	1–>32	34.8	>64/>64	1–>64	0.6	8/32	≤0.25–>64	60.3
AmpC-hyperproducing	0.12/0.5	≤0.06–2	100	16/>32	1–>32	41.4	8/32	≤0.25–>64	40.2	≤0.25/0.5	≤0.25–2	100
Klebsiella oxytoca	0.12/2	≤0.06–2	100	≤0.25/0.5	≤0.25–>32	99.3	≤0.25/0.5	≤0.25–>64	93.3	≤0.25/≤0.25	≤0.25–2	100
Klebsiella pneumoniae	0.12/0.5	≤0.06–8	99.9	≤0.25/1	≤0.25–.32	98.5	≤0.25/≤0.25	≤0.25–>64	96	≤0.25/≤0.25	≤0.25–64	98.5
ESBL-producing	0.5/1	≤0.06–2	100	32/>32	4–64	66.7	64/>64	≤0.25–>64	10.8	4/64	≤0.25–64	66.7
OXA-48-producing	0.25/0.5	<0.008–1	100	256/512	≤0.12–512	N/A	N/A	N/A	N/A	32/512	N/A	N/A
KPC-producing	0.25/1	≤0.06–1	100	>256/>256	32–>256	0	N/A	N/A	N/A	32/128	N/A	N/A
Carbapenem-non-susceptible	0.5/2	≤0.03–32	N/A	>32/>32	N/A	N/A	N/A	N/A	N/A	>16/>16	N/A	N/A
Morganella morganii	≤0.06/0.12	≤0.06–0.5	100	≤0.25/8	≤0.25–16	89.7	≤0.25/1	≤0.25–8	96.6	≤0.25/≤0.25	≤0.25–≤0.25	100
Proteus mirabilis	≤0.06/0.12	≤0.06–0.25	100	≤0.25/≤0.25	≤0.25–32	99.6	≤0.25/≤0.25	≤0.25–16	98	≤0.25/≤0.25	≤0.25–1	100
Proteus vulgaris	0.06/0.25	≤0.03–2	100	0.12/8	N/A	N/A	N/A	N/A	N/A	≤0.12/0.5	N/A	N/A
Salmonella enterica	0.25/0.5	≤0.03–0.5	100	0.25/0.5	N/A	N/A	0.06/0.125	N/A	N/A	≤0.12/0.25	N/A	N/A
Serratia marcescens	0.25/0.5	≤0.06–2	100	≤0.25/1	≤0.25–16	99.6	≤0.25/1	≤0.25–64	93.8	≤0.25/≤0.25	≤0.25–8	100
Burkholderia cepacia	8/>128	≤1–>128	N/A	64/>128	8–>128	N/A	N/A	N/A	N/A	N/A	N/A	N/A
Pseudomonas aeruginosa	2/8	≤0.06–>16	94.7	4/32	≤0.25–>32	82.8	16/>64	≤0.25–>64	N/A	4/16	≤0.25–>64	84.9
Multidrug-resistant	8/>16	4–>16	60.0	>16/>16	4–>16	4.	N/A	N/A	N/A	N/A	N/A	NA
AmpC-derepressed	4/8	≤1–64	96.2	64/.126	8–>128	3.8	N/A	N/A	N/A	N/A	N/A	NA
Acinetobacter baumannii	8/>16	0.5–>16	60.3	8/>32	N/A	78.2	8/64	2–>64	55.1	2/32	0.5–>64	82
Carbapenem-resistant	32/>32	0.25–>32	N/A	>32/>32	N/A	N/A	N/A	N/A	N/A	>16/>16	N/A	N/A
Haemophilus influenzae	≤0.06/≤0.06	≤0.06–0.1	100	N/A	N/A	N/A	≤0.06/≤0.06	≤0.06–0.25	100	≤0.25/≤0.25	≤0.25–0.5	100

Notes: MICs were measured in μg/mL. Susceptibility rates for ceftazidime, ceftriaxone, and cefepime were determined by Clinical and Laboratory Standards Institute (CLSI) breakpoints (M100). Susceptibility breakpoints for ceftazidime were applied to ceftazidime–avibactam.

Abbreviations: %S, percent of isolates susceptible to antimicrobial agents; ESBL, extended-spectrum β-lactamase; KPC, Klebsiella pneumoniae carbapenemase; MIC, minimum inhibitory concentration; MIC₅₀, MIC that inhibits 50% of isolates; MIC₉₀, MIC that inhibits 90% of isolates; N/A, not available.