TABLE 4.

Antimicrobial susceptibilities of Elizabethkingia isolates determined by the agar dilution method

Species (no. of isolates) and antimicrobial agents	Breakpoint (μg/ml)a		MIC (μg/ml)			Susceptibility (%)
	S	R	Range	50%	90%	S	I	R
E. meningoseptica (17)
Piperacillin	≤16	≥128	16–32	16	32	65	35	0
Piperacillin-tazobactamb	≤16	≥128	8–16	8	16	100	0	0
Ceftazidime	≤8	≥32	64 to >128	>128	>128	0	0	100
Imipenem	≤4	≥16	16–32	32	32	0	0	100
Ciprofloxacin	≤1	≥4	1 to >64	64	>64	23	6	71
Levofloxacin	≤2	≥8	0.5–128	16	64	35	0	65
Moxifloxacin	≤2	≥8	0.12–64	4	32	41	12	47
Gatifloxacin	≤2	≥8	0.5–128	8	64	35	12	53
Trimethoprim-sulfamethoxazoleb	≤2	≥4	2–8	4	4	6	0	94
Gentamicin	≤4	≥16	4 to >128	32	64	6	0	94
Vancomycin	≤4	≥32	8–64	8	16	0	94	6
Rifampin	≤1	≥4	0.25–2	0.5	1	94	6	0
E. miricola (18)
Piperacillin	≤16	≥128	4–32	16	32	83	17	0
Piperacillin-tazobactam	≤16	≥128	4–32	8	16	94	6	0
Ceftazidime	≤8	≥32	64 to ≥128	>128	>128	0	0	100
Imipenem	≤4	≥16	16 to ≥64	64	64	0	0	100
Ciprofloxacin	≤1	≥4	0.5–4	1	4	56	22	22
Levofloxacin	≤2	≥8	0.25–2	0.5	2	100	0	0
Moxifloxacin	≤2	≥8	≤0.06–1	0.25	1	100	0	0
Gatifloxacin	≤2	≥8	0.12–2	0.5	2	100	0	0
Trimethoprim-sulfamethoxazole	≤2	≥4	1–8	4	8	28	0	72
Gentamicin	≤4	≥16	4 to >128	8	>128	45	22	33
Vancomycin	≤4	≥32	8–16	16	16	0	100	0
Rifampin	≤1	≥4	0.25 to >128	1	16	66	17	17
E. anophelis (51)
Piperacillin	≤16	≥128	8–64	16	32	82	18	0
Piperacillin-tazobactam	≤16	≥128	≤0.12–32	8	8	92	8	0
Ceftazidime	≤8	≥32	64 to >128	>128	>128	0	0	100
Imipenem	≤4	≥16	16 to >64	64	>64	0	0	100
Ciprofloxacin	≤1	≥4	1 to >64	64	>64	22	6	72
Levofloxacin	≤2	≥8	0.5 to >128	32	64	29	6	65
Moxifloxacin	≤2	≥8	0.12–64	4	32	41	10	49
Gatifloxacin	≤2	≥8	0.25–128	8	32	33	12	55
Trimethoprim-sulfamethoxazole	≤2	≥4	2–16	4	8	22	0	78
Gentamicin	≤4	≥16	1 to >128	32	64	22	23	55
Vancomycin	≤4	≥32	8–64	16	16	0	94	6
Rifampin	≤1	≥4	≤0.06–16	1	1	96	2	2

^aThe interpretive criteria applied were those of the CLSI for non-Enterobacteriaceae; the criteria for vancomycin and rifampin were those for Staphylococcus or Enterococcus spp. The criterion of gatifloxacin was that for moxifloxacin.

^bIn the combinations, the concentration of tazobactam was 4 μg/ml constant, and the ratio of trimethoprim to sulfamethoxazole was 1 to 19.