TABLE 1.

In vitro activities of MK-0826 and 16 other antimicrobial agents against B. fragilis group strains

Organism (no. of isolates) and antimicrobial	MIC (μg/ml)			% Resistant strainsa
	Range	50%	90%
B. fragilis group (309)
MK-0826	≤0.06–4	0.5	2	—
Metronidazole	0.1–4	1	2	0
Chloramphenicol	1–8	4	8	0
Clindamycin	≤0.06–>256	2	>256	38.8
Trovafloxacin	0.2–64	0.2	2	3.6
Moxifloxacin	≤0.06–128	0.5	4	—
Cefoxitin	≤0.06–256	8	32	5.5
Cefminox	≤0.06–>256	2	64	10
Cefotetan	≤0.06–256	16	128	36.2
Ceftizoxime	≤0.06–>256	16	256	20.7
Piperacillin	0.2–>256	32	>256	29.4
Imipenem	≤0.06–4	0.5	2	0
Meropenem	0.1–4	0.2	1	0
Amoxicillin-clavulanate	0.5–64	2	8	8.4
Ampicillin-sulbactam	0.1–64	2	16	3.9
Ticarcillin-clavulanate	≤0.06–128	0.5	16	0.3
Piperacillin-tazobactam	≤0.06–64	0.2	16	0
B. fragilis (189)
MK-0826	≤0.06–4	0.2	1	—
Metronidazole	0.1–4	1	2	0
Chloramphenicol	1–8	4	8	0
Clindamycin	≤0.06–>256	1	>256	38.6
Trovafloxacin	≤0.06–64	0.2	2	2.1
Moxifloxacin	≤0.06–64	0.2	4	—
Cefoxitin	≤0.06–256	8	32	2.1
Cefminox	≤0.06–256	1	32	10.1
Cefotetan	≤0.06–256	8	64	16.9
Ceftizoxime	≤0.06–>256	8	128	12.7
Piperacillin	0.2–>256	8	256	18
Imipenem	≤0.06–4	0.5	1	0
Meropenem	0.1–4	0.2	1	0
Amoxicillin-clavulanate	0.5–64	1	8	7.4
Ampicillin-sulbactam	0.1–32	1	8	1.6
Ticarcillin-clavulanate	<0.06–64	0.2	8	0
Piperacillin-tazobactam	≤0.06–64	0.1	4	0
B. thetaiotaomicron (36)
MK-0826	≤0.06–4	1	2	—
Metronidazole	0.2–4	1	2	0
Chloramphenicol	2–8	4	8	0
Clindamycin	0.1–>256	4	>256	36.1
Trovafloxacin	0.2–8	0.5	2	5.6
Moxifloxacin	0.2–32	1	4	—
Cefoxitin	≤0.06–128	32	32	8.3
Cefminox	0.5–128	8	128	33.3
Cefotetan	2–256	64	256	66.7
Ceftizoxime	0.2–>256	32	>256	36.1
Piperacillin	4–>256	64	>256	44.4
Imipenem	≤0.06–4	1	4	0
Meropenem	0.2–4	0.5	1	0
Amoxicillin-clavulanate	0.5–64	2	16	19.4
Ampicillin-sulbactam	0.5–64	4	16	11.1
Ticarcillin-clavulanate	0.1–128	2	16	2.8
Piperacillin-tazobactam	≤0.06–32	8	32	0
B. uniformis (36)
MK-0826	≤0.06–4	0.5	2	—
Metronidazole	0.5–4	1	2	0
Chloramphenicol	1–8	4	8	0
Clindamycin	≤0.06–>256	4	>256	47.2
Trovafloxacin	≤0.06–16	0.5	8	11.1
Moxifloxacin	≤0.06–128	1	16	—
Cefoxitin	≤0.06–64	8	32	5.6
Cefminox	≤0.06–128	2	64	16.7
Cefotetan	≤0.06–256	32	128	41.7
Ceftizoxime	≤0.06–>256	16	>256	36.1
Piperacillin	2–>256	32	>256	38.9
Imipenem	≤0.06–4	0.5	2	0
Meropenem	0.1–4	0.2	1	0
Amoxicillin-clavulanate	0.5–32	2	16	16.7
Ampicillin-sulbactam	1–32	2	16	5.6
Ticarcillin-clavulanate	≤0.06–32	1	16	0
Piperacillin-tazobactam	≤0.06–32	0.2	16	0
B. distasonis (18)
MK-0826	≤0.06–2	0.5	2	—
Metronidazole	0.5–4	1	2	0
Chloramphenicol	1–8	4	8	0
Clindamycin	≤0.06–>256	1	256	22.2
Trovafloxacin	≤0.06–4	0.5	1	0
Moxifloxacin	≤0.06–2	0.5	2	—
Cefoxitin	≤0.06–128	32	64	22.2
Cefminox	≤0.06–256	32	128	50
Cefotetan	≤0.06–256	128	256	88.9
Ceftizoxime	≤0.06–>256	16	256	27.8
Piperacillin	4–>256	256	>256	66.7
Imipenem	0.2–4	1	2	0
Meropenem	0.1–4	0.2	1	0
Amoxicillin-clavulanate	0.5–32	8	16	16.5
Ampicillin-sulbactam	1–64	8	16	5.6
Ticarcillin-clavulanate	≤0.06–64	16	32	0
Piperacillin-tazobactam	≤0.06–32	16	16	0
B. vulgatus (10)
MK-0826	≤0.06–2	0.2	1	—
Metronidazole	0.5–2	2	2	0
Chloramphenicol	2–8	4	8	0
Clindamycin	≤0.06–>256	1	>256	30
Trovafloxacin	0.1–1	0.2	1	0
Moxifloxacin	0.5–4	1	4	—
Cefoxitin	2–32	16	32	0
Cefminox	1–128	16	64	30
Cefotetan	4–128	64	128	60
Ceftizoxime	≤0.06–>256	64	64	10
Piperacillin	4–256	64	128	50
Imipenem	0.2–1	1	1	0
Meropenem	0.1–1	1	1	0
Amoxicillin-clavulanate	1–16	2	16	20
Ampicillin-sulbactam	1–32	4	16	10
Ticarcillin-clavulanate	≤0.06–32	0.5	16	0
Piperacillin-tazobactam	≤0.06–32	0.5	32	0

^aMICs (in micrograms per milliliter) from the NCCLS for resistant isolates are as follows: metronidazole and chloramphenicol, ≥32; clindamycin and trovafloxacin, ≥8; cefoxitin, cefminox and cefotetan, ≥64; piperacillin and ceftizoxime, ≥128; imipenem and meropenem, ≥16; amoxicillin-clavulanate ≥16–8; ampicillin-sulbactam, ≥32–16; ticarcillin-clavulanate, ≥128–2; piperacillin-tazobactam, ≥128–4. —, breakpoints for moxifloxacin and MK-0826 are not currently provided by the NCCLS for anaerobes.