TABLE 2.

Susceptibilities of clinical isolates of S. pneumoniae to fluoroquinolones and efflux pump substrates

Group	Compound	MIC (μg/ml)a
		50%	90%	Range	Geometric mean
A (n = 149)	Norfloxacin	16	32	4–256	14.0
	Norfloxacin + reserpine	8	16	4–128	7.7
	Ciprofloxacin	2	4	1–128	2.4
	Sparfloxacin	0.5	1	0.25–32	0.6
	Moxifloxacin	0.25	0.5	0.12–8	0.3
	Ethidium bromide	8	16	2–32	7.0
	Acriflavine	8	16	4–32	7.4
B (n = 124)	Norfloxacin	16	32	8–128	18.7
	Norfloxacin + reserpine	4	8	2–32	4.3
	Ciprofloxacin	2	4	2–8	2.5
	Sparfloxacin	0.5	0.5	0.25–8	0.4
	Moxifloxacin	0.25	0.25	0.12–0.5	0.2
	Ethidium bromide	16	32	4–32	16.6
	Acriflavine	16	32	4–64	17.9

^a50% and 90%, MICs at which 50 and 90% of isolates are inhibited, respectively.