TABLE 2.

Antimicrobial susceptibility testing and MIC distribution for A. schaalii based on CLSI and EUCAST v12.0 breakpoints for Corynebacterium spp.

Antimicrobial agent	No. of isolates with MICs of:													MIC50 (μg/mL)	MIC90 (μg/mL)	Susceptible (%) usinga:
	<0.06 μg/mL	0.12 μg/mL	0.25 μg/mL	0.5 μg/mL	1 μg/mL	2 μg/mL	4 μg/mL	8 μg/mL	16 μg/mL	32 μg/mL	64 μg/mL	128 μg/mL	>256 μg/mL			CLSI breakpoint	EUCAST breakpoint
Penicillin	47	3	0	0	0	0	0	0	0	0	0	0	0	<0.06	<0.06	100	100
Piperacillin-tazobactam	16	3	2	0	2	0	0	0	0	0	0	0	0	<0.06	0.25	NAb	NA
Ceftriaxone	9	1	0	0	0	0	0	0	0	0	0	0	0	<0.06	<0.06	100	NA
Imipenem	9	0	0	0	0	0	0	0	0	0	0	0	0	<0.06	<0.06	NA	NA
Meropenem	8	0	0	0	0	0	0	0	0	0	0	0	0	<0.06	<0.06	100	NA
Metronidazole	0	0	0	0	0	0	0	0	0	0	0	0	34	>256	>256	NA	NA
Clindamycin	10	2	0	0	0	0	0	0	0	1	0	0	9	0.12	>256	55	55
TMP-SMX	5	0	1	0	0	0	0	0	0	2	1	0	0	<0.06	32	67	NA
Tetracycline	1	0	1	0	0	0	0	0	0	0	0	0	0	—c	—	—	—
Erythromycin	2	0	0	0	0	0	0	0	0	0	0	0	2	—	—	—	NA
Gentamicin	0	0	0	0	2	0	1	0	0	0	0	0	0	—	—	—	NA
Ciprofloxacin	0	0	0	0	0	1	2	0	0	0	0	0	0	—	—	—	—
Moxifloxacin	1	0	0	0	0	0	0	0	0	0	0	0	0	—	—	NA	—
Vancomycin	5	10	5	2	0	0	0	0	0	0	0	0	0	0.12	0.25	100	100

^aPercentage of susceptible isolates based on CLSI and EUCAST v12.0 MIC breakpoints (15, 24).

^bNA, not applicable (no established breakpoints).

^c—, Antimicrobial agent was tested ≤5 times, and MIC₅₀, MIC₉₀, and susceptibility values were not calculated.