TABLE 2.

Activity of aztreonam–β-lactamase inhibitor combinations and comparator agents against tested clinical Stenotrophomonas maltophilia isolates stratified according to infection type, acquisition setting, and geographic location^a

Parameter and agent(s)	MIC (mg/liter)			% susceptible	MIC (mg/liter)			% susceptible
	50%	90%	Range		50%	90%	Range
Infection type	Pneumonia (n = 36)				Nonpneumonia (n = 11)
Aztreonam	≥256	≥256	64 to ≥256	0	≥256	≥256	8 to ≥256	9.1
Aztreonam-avibactam	2	4	0.5 to 16	97.2	4	4	1 to 8	100
Aztreonam-clavulanate	8	≥256	2 to ≥256	61.1	4	≥256	1 to ≥256	63.6
Aztreonam-relebactam	8	16	1 to 128	69.4	4	16	1 to 32	81.8
Aztreonam-vaborbactam	32	128	4 to ≥256	13.9	32	64	2 to ≥256	27.3
Amoxicillin-clavulanate	≥256	≥256	16 to ≥256		≥256	≥256	64 to ≥256
Ceftazidime-avibactamb	64	128	0.125 to ≥256	22.2	32	128	1 to ≥256	36.4
Imipenem-relebactam	≥64	≥64	0.5 to ≥64		≥64	≥64	≥64 to ≥64
Levofloxacin	4	≥32	0.25 to ≥32	36.1	4	16	0.5 to ≥32	45.5
Meropenem-vaborbactam	≥64	≥64	0.25 to ≥64		≥64	≥64	16 to ≥64
Trimethoprim-sulfamethoxazolec	8	≥16	0.03 to ≥16	44.4	8	≥16	0.125 to ≥16	45.5
Acquisition setting	Community (n = 21)				Nosocomial (n = 18)
Aztreonam	≥256	≥256	8 to ≥256	4.8	≥256	≥256	64 to ≥256	0
Aztreonam-avibactam	2	8	1 to 16	95.2	2	4	0.5 to 8	100
Aztreonam-clavulanate	8	≥256	1 to ≥256	61.9	8	≥256	2 to ≥256	61.1
Aztreonam-relebactam	8	16	1 to 128	76.2	8	32	2 to 128	72.2
Aztreonam-vaborbactam	64	≥256	2 to ≥256	23.8	32	≥256	8 to ≥256	11.1
Amoxicillin-clavulanate	≥256	≥256	16 to ≥256		≥256	≥256	≥256 to ≥256
Ceftazidime-avibactamb	64	≥256	0.125 to ≥256	38.1	64	128	1 to ≥256	16.7
Imipenem-relebactam	≥64	≥64	0.5 to ≥64		≥64	≥64	32 to ≥64
Levofloxacin	4	8	0.5 to ≥32	47.6	8	≥32	0.25 to ≥32	27.8
Meropenem-vaborbactam	≥64	≥64	0.25 to ≥64		≥64	≥64	16 to ≥64
Trimethoprim-sulfamethoxazolec	8	≥16	0.125 to ≥16	47.6	8	≥16	0.125 to 8	44.4
Location	U.S. (n = 21)				Non-U.S. (n = 26)
Aztreonam	≥256	≥256	8 to ≥256	4.8	≥256	≥256	64 to ≥256	0
Aztreonam-avibactam	2	4	0.5 to 8	100	2	8	0.5 to 16	96.2
Aztreonam-clavulanate	8	≥256	1 to ≥256	66.7	8	≥256	2 to ≥256	57.7
Aztreonam-relebactam	8	16	1 to 32	66.7	8	32	2 to 128	77.0
Aztreonam-vaborbactam	32	128	2 to ≥256	28.6	32	≥256	8 to ≥256	7.7
Amoxicillin-clavulanate	≥256	≥256	16 to ≥256		≥256	≥256	≥256 to ≥256
Ceftazidime-avibactamb	64	128	0.125 to ≥256	28.6	64	≥256	1 to ≥256	23.1
Imipenem-relebactam	≥64	≥64	0.5 to ≥64		≥64	≥64	32 to ≥64
Levofloxacin	4	≥32	0.25 to ≥32	47.6	8	≥32	0.5 to ≥32	30.8
Meropenem-vaborbactam	≥64	≥64	0.25 to ≥64		≥64	≥64	32 to ≥64
Trimethoprim-sulfamethoxazolec	8	≥16	0.03 to ≥16	42.9	8	≥16	0.25 to ≥16	46.2

^aNo statistically significant differences in MIC distribution were present for any agent based on infection type, acquisition setting, or location using the Mann-Whitney U test. Susceptibility interpretations of aztreonam-based regimens were based on CLSI aztreonam interpretive criteria against P. aeruginosa (34).

^bSusceptibility interpretation based on CLSI ceftazidime interpretative criteria against S. maltophilia (34).

^cReflects the MIC of the trimethoprim component only.