TABLE 1.

Agar dilution MICs for 261 pneumococcal strains classified by penicillin susceptibility

Drug and strain category (n)a	MIC (μg/ml)
	Range	50%	90%
Penicillin G
Penicillin S (86)	0.016-0.06	0.03	0.03
Penicillin I (81)	0.125-1.0	0.25	1.0
Penicillin R (94)	2.0-16.0	2.0	4.0
XPR 2868
Penicillin S	0.06-0.25	0.125	0.25
Penicillin I	0.06-0.5	0.25	0.25
Penicillin R	0.06-1.0	0.25	0.5
RPR 132552
Penicillin S	<0.5-16.0	4.0	8.0
Penicillin I	≤0.5-64.0	4.0	8.0
Penicillin R	≤0.5->64.0	4.0	32.0
RPR 202868
Penicillin S	≤0.5->64.0	4.0	16.0
Penicillin I	1.0->64.0	8.0	32.0
Penicillin R	1.0->64.0	16.0	64.0
Pristinamycin
Penicillin S	0.125-0.5	0.25	0.25
Penicillin I	0.125-1.0	0.25	0.5
Penicillin R	0.125-1.0	0.25	0.5
Quinupristin/dalfopristin
Penicillin S	≤0.06-1.0	0.5	0.5
Penicillin I	0.125-1.0	0.5	1.0
Penicillin R	0.125-1.0	0.5	1.0
Quinupristin
Penicillin S	≤0.5-64.0	2.0	4.0
Penicillin I	≤0.5->64.0	4.0	32.0
Penicillin R	≤0.5->64.0	4.0	32.0
Dalfopristin
Penicillin S	8.0->64.0	64.0	>64.0
Penicillin I	8.0->64.0	64.0	>64.0
Penicillin R	16.0->64.0	>64.0	>64.0
Erythromycin A
Penicillin S	0.016->64.0	0.125	32.0
Penicillin I	0.03->64.0	0.125	>64.0
Penicillin R	0.03->64.0	>64.0	>64.0
Azithromycin
Penicillin S	0.03->64.0	0.125	16.0
Penicillin I	0.06->64.0	0.125	>64.0
Penicillin R	0.06->64.0	>64.0	>64.0
Clarithromycin
Penicillin S	≤0.008->64.0	0.03	8.0
Penicillin I	0.016->64.0	0.06	>64.0
Penicillin R	≤0.008->64.0	32.0	>64.0
Clindamycin
Penicillin S	≤0.008->64.0	0.06	0.06
Penicillin I	0.016->64.0	0.06	>64.0
Penicillin R	0.016->64.0	0.06	>64.0

^aS, susceptible; I, intermediate; R, resistant.