Table 2.

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

GroupCompoundMIC (μg/ml)a
50%90%RangeGeometric mean
A (n = 149)Norfloxacin16324–25614.0
Norfloxacin + reserpine8164–1287.7
Ciprofloxacin241–1282.4
Sparfloxacin0.510.25–320.6
Moxifloxacin0.250.50.12–80.3
Ethidium bromide8162–327.0
Acriflavine8164–327.4
B (n = 124)Norfloxacin16328–12818.7
Norfloxacin + reserpine482–324.3
Ciprofloxacin242–82.5
Sparfloxacin0.50.50.25–80.4
Moxifloxacin0.250.250.12–0.50.2
Ethidium bromide16324–3216.6
Acriflavine16324–6417.9
  • a 50% and 90%, MICs at which 50 and 90% of isolates are inhibited, respectively.