TABLE 2.

In vitro activities of eight antimicrobial agents against the 79 clinical isolates of S. pneumoniae by agar dilution^a

Antimicrobial agent	Penicillin-susceptible strains (n = 68)b					Penicillin-intermediate and -resistant strains (n = 11)c
	R (%)	I (%)	MIC50	MIC90	MIC range	R (%)	I (%)	MIC50	MIC90	MIC range
Amoxicillin-clavulanate	0	0	0.064	0.064	≤0.064–0.125	9.1	0	0.064	0.25	≤0.064–2
Cefuroxime	0	0	0.064	0.25	≤0.064–0.5	18.2	0	0.125	4	≤0.064–8
Cefotaxime	0	0	0.064	0.064	≤0.064–0.25	0	9.1	0.064	0.25	≤0.064–1
Ceftriaxone	0	0	0.064	0.064	≤0.064–0.5	0	9.1	0.064	0.25	≤0.064–1
Vancomycin	0	0	0.5	1	≤0.125–1	0	0	0.5	1	≤0.5–1
Tetracycline	52.9	1.5	8	32	≤0.25–32	27.3	9.1	0.25	32	≤0.25–32
Erythromycin	39.7	0	0.032	16	≤0.032–16	45.5	0	0.125	16	≤0.032–16
Chloramphenicol	17.6	0	2	16	≤0.5–16	9.1	0	0.5	4	≤0.5–16

^aAll MICs given are in micrograms per milliliter. R, resistant strains; I, intermediate strains. 

^bSusceptible, MIC ≤ 0.064 μg/ml. 

^cIntermediate, MIC = 0.125 to 1 μg/ml; resistant, MIC ≥ 2 μg/ml.