Table 2.

Clinical and Laboratory Standards Institute Minimum Inhibitory Concentration (mg/L) Breakpoints and In Vitro Activity of Select Agents Against Stenotrophomonas maltophilia^a

Antimicrobial	Susceptible	Intermediate	Resistant	Count	MIC50	MIC90	% Susceptible	% Resistant
TMP-SMXb	≤2/38	…	≥4/76	2095	≤0.5	1	95	5
Levofloxacinb	≤2	4	≥8	2099	1	>4	75	15
Minocyclineb	≤4	8	≥16	1977	0.5	2	99	0.2
Ceftazidimeb	≤8	16	≥32	2098	32	>32	26	64
T/Cc	≤16/2	32/2 to 64/2	≥128/2	130	32	128	43d	57
Chloramphenicole	≤8	16	≥32	66	4	16	80	NR
Cefiderocolf	≤4	8	≥16	217	0.06	0.25	100	0

Abbreviations: MIC₅₀, minimum inhibitory concentration at which ≥50% isolates inhibited; MIC₉₀, minimum inhibitory concentration at which ≥90% of isolates inhibited; NR, not reported; T/C, ticarcillin-clavulanate; TMP-SMX, trimethoprim-sulfamethoxazole.

According to Clinical and Laboratory Standards Institute M100-S30.

Data from United States (US) medical centers as part of the SENTRY surveillance program (JMI Laboratories, North Liberty, Iowa).

No longer commercially available in the US. Breakpoints extrapolated from Pseudomonas aeruginosa. Data from Vartivarian S, Anaissie E, Bodey G, et al. A changing pattern of susceptibility of Xanthomonas maltophilia to antimicrobial agents: implications for therapy. Antimicrob Agents Chemother 1994; 38:624–7.

% susceptible includes intermediate isolates as breakpoint was ≤64 mg/L at the time.

Limited availability in the US. Data from Nicodemo AC, Araujo MRE, Ruiz AS, Gales AC. In vitro susceptibility of Stenotrophomonas maltophilia isolates: Comparison of disc diffusion, Etest and agar dilution methods. J Antimicrob Chemother 2004; 53:604–8.

Investigational breakpoints. Data from Hackel MA, Tsuji M, Yamano Y, et al. In vitro activity of the siderophore cephalosporin, cefiderocol, against carbapenem-nonsusceptible and multidrug-resistant isolates of gram-negative bacilli collected worldwide in 2014 to 2016. Antimicrob Agents Chemother 2018; 62:e01968-17.