Table 3.

MIC50s, MIC90s, and ranges of MICs of CAZ-AVI and ATM-AVI for 76 S. maltophilia isolates from clinical specimens^a

Drug resistance phenotype (s) b (no. of isolates)	CAZ			CAZ + AVI			CAZ-AVI MIC50 reduction (fold)	ATM			ATM + AVI			ATM-AVI MIC50 reduction (fold)
	MIC50	MIC90	range	MIC50	MIC90	range		MIC50	MIC90	range	MIC50	MIC90	range
Total(76)	8	64	0.03–64	2	64	0.016–64	4	64	64	1–1024	2	8	0.06–64	32
MH-NSc or LVX-NS or SXT-NS (60)	16	64	0.03–64	4	16	0.016–64	4	64	64	1–1024	2	8	0.06–64	32
MH-Sd and LEV-S and SXT-S (16)	4	8	1–16	2	2	0.25–8	2	64	64	64	2	2	0.5–64	32
MDR (2)	NAe	NA	> = 64	NA	NA	16- > 64	NA	NA	NA	64	NA	NA	2–8	NA

^aMICs are expressed in μg/mL

^bCAZ ceftazidime, ATM aztreonam, AVI avibactam, MDR multidrug resistant. Multidrug-resistant isolates were defined as isolates demonstrating resistance to at least one antimicrobial agent from three or more different classes

^cNS not susceptible, ^dS susceptible, ^eNA not applicable. MIC50s and MIC90s are not presented for groups of fewer than 6 isolates