TABLE 5.

In vitro activities of ceftazidime-avibactam against Escherichia coli and Klebsiella pneumoniae baseline isolates by the presence or absence of extended-spectrum β-lactamases for all randomized patients^a

ESBL status by baseline pathogen (no. of pathogens tested)	MIC (mg/liter)
	Range	MIC50	MIC90
Escherichia coli
ESBL positive (61)	≤0.008 to 0.5	0.12	0.25
ESBL negative (487)	≤0.008 to 4	0.06	0.12
Klebsiella pneumoniae
ESBL positive (24)	0.12 to 2	0.25	1
ESBL negative (76)	≤0.008 to >256	0.12	0.12

^aTotal of 1,066 randomized patients. ESBL, extended-spectrum β-lactamase; NA, not applicable. ESBL status was determined by phenotype based on CLSI confirmatory tests. Some patients had more than one pathogen isolated. Multiple isolates of the same species from the same patient were 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 were counted only once using the isolate with the highest MIC to the study drug received across culture source (intra-abdominal site or blood).