TABLE 1.

Susceptibility of pneumococcal CSF isolates to antimicrobial agents by penicillin susceptibility

Antimicrobial agent and penicillin susceptibility of isolates (n)a	MIC (μg/ml)b
	Range	50%	90%
Penicillin
S (29)	0.016–0.06	0.032	0.064
I (29)	0.125–1.0	0.5	1.0
R (22)	2.0	2.0	2.0
Meropenem
S	<0.015–0.06	0.015	0.06
I	<0.015–0.5	0.12	0.5
R	0.12–0.25	0.5	0.5
Imipenem
S	<0.015–0.03	<0.015	0.015
I	<0.015–0.25	0.06	0.25
R	0.12–0.25	0.25	0.25
Ceftriaxone
S	0.015–0.06	0.015	0.015
I	0.015–0.5	0.12	0.5
R	0.5–1.0	1.0	1.0
Vancomycin
S	0.125–0.25	0.25	0.25
I	0.25	0.25	0.25
R	0.25	0.25	0.25

^aS, susceptible (≤0.06 μg/ml); I, intermediate (0.125 to 1.0 μg/ml); R, resistant (≥2.0 μg/ml). n, number of strains. 

^b50% and 90%, MIC₅₀ and MIC₉₀, respectively.