TABLE 2.

In vitro antimicrobial susceptibilities for S. pneumoniae isolates obtained from pediatric patients with acute conjunctivitis (1997–1998)

Antibiotic	MIC (μg/ml)a
	Penicillin-susceptible strains (n = 44)			Penicillin-nonsusceptible strains (n = 21)
	50%	90%	Range	50%	90%	Range
Penicillin	0.02	0.06	0.004–0.06	2	8	0.5–8
Cefazolin	0.06	0.13	0.03–0.13	4	16	2–32
Tobramycin	16	32	4–64	16	64	1–64
Gentamicin	8	16	0.25–32	8	16	1–32
Neomycin	64	128	16–128	64	128	8–256
Polymyxin Bb	>520	>520	130–520	>520	>520	260–>520
Polymyxin B–neomycinb	32/103	64/205	16/52–130/413	64/206	128/413	2/6.4–130/413
Trimethoprim	4	8	2–128	128	256	4–512
Polymyxin B–trimethoprimb	4.1/3.3	16.3/13	2/1.6–280/210	280/210	520/430	4.1/3.3–520/420
Ciprofloxacin	0.5	1	0.13–1	1	1	0.13–1
Ofloxacin	1	2	0.25–2	1	2	0.13–2
Chloramphenicol	2	4	1–4	4	16	2–16
Tetracycline	0.13	0.25	0.13–32	0.25	16	0.13–32
Erythromycin	0.13	0.13	0.03–8	4	16	0.06–16
Clindamycin	0.13	0.25	0.03–0.25	0.13	4	0.06–8
Sulfamethoxazole	32	>256	16–256	256	>256	16–>256

^a50% and 90%, MIC₅₀ and MIC₉₀, respectively. 

^bPolymyxin B is expressed in μg/ml. The specific activity of the formualtion used was 7,500 IU/mg.