TABLE 1.

MIC₅₀, MIC₉₀, ranges, and susceptibility percentages of the antibiotics tested for different groups of species^a

Antibiotic	MIC	All strains	Streptococcus group
			S. mitis (n = 72)	S. anginosus (n = 49)	S. sanguis (n = 21)	S. salivarius (n = 11)	S. bovis (n = 18)
Penicillin	Range	≤0.03-64	≤0.03-64	≤0.03-2	≤0.03-2	0.06-8	0.03-2
	MIC50	0.06	0.12	0.06	0.12	0.25	0.06
	MIC90	2	4	0.12	0.25	1	0.25
	% S	71.1	55	94	57	64	89
	% I	21.3	28	6	43	27	11
	% R	7.6	17	0	0	9	0
Erythromycin	Range	≤0.03-256	0.06-256	≤0.03-256	0.06-256	0.06-256	0.06-256
	MIC50	0.12	0.12	0.12	1	0.06	256
	MIC90	256	128	256	64	4	256
	% S	52.6	50	63	48	73	22
	% I	1.8	4	0	0	0	0
	% R	45.6	46	37	52	27	78
Clindamycin	Range	≤0.03-256	≤0.03-256	≤0.03-128	≤0.03-64	≤0.03-0.12	≤0.03-256
	MIC50	0.06	0.06	0.06	0.06	0.06	64
	MIC90	256	128	128	32	0.12	256
	% S	72.3	78	69	81	100	28
	% I	0	0	0	0	0	0
	% R	27.7	22	31	19	0	72
Telithromycin	Range	≤0.015-128	≤0.015-2	≤0.015-1	≤0.015-0.25	≤0.015-0.06	≤0.015-128
	MIC50	≤0.015	≤0.015	≤0.015	≤0.015	≤0.015	0.12
	MIC90	0.25	0.12	0.12	0.12	0.03	64
	% S	95.5	99	100	100	100	61
	% I	0.5	1	0	0	0	0
	% R	4	0	0	0	0	39

^aMIC₅₀, MIC at which 50% of the isolates tested are inhibited; MIC₉₀, MIC at which 90% of the isolates tested are inhibited; % S, percent susceptible; % I, percent intermediate; % R, percent resistant. All MICs are in micrograms per milliliter.