Table 1.

PAEs of gatifloxacin against 12 strains

StrainaMean (range) effect (h)b
PAE0.2 × MIC0.3 × MIC0.4 × MIC
SMEPA-SMESMEPA-SMESMEPA-SME
Pen-S S. pneumoniae 4.0 (4.0–4.0)0.9 (0.7–1.1)4.7 (4.0–5.3)2.4 (2.0–2.7)6.8 (5.5–8.0)4.6 (4.4–4.7)8.6 (8.0–9.1)
Pen-S S. pneumoniae 1.4 (1.0–1.7)2.4 (1.6–3.2)3.6 (2.7–4.5)4.9 (4.7–5.0)5.5 (4.7–6.3)7.8 (7.2–8.3)8.1 (6.9–9.3)
Pen-I S. pneumoniae 1.2 (0.8–1.6)1.5 (1.3–1.7)2.4 (1.4–3.3)2.5 (1.8–3.2)2.8 (2.4–3.1)3.1 (2.5–3.6)3.7 (3.5–3.8)
Pen-I S. pneumoniae 1.2 (0.9–1.4)1.4 (1.3–1.6)2.8 (2.4–3.1)3.8 (2.4–5.1)4.2 (4.1–4.2)5.0 (4.1–5.9)7.9 (7.0–8.8)
Pen-R S. pneumoniae 1.6 (1.5–1.6)1.5 (1.0–2.0)3.1 (2.1–4.0)3.8 (3.0–4.6)4.3 (3.6–5.0)5.5 (5.0–6.0)7.8 (5.6–10.0)
Pen-R S. pneumoniae 1.3 (1.2–1.3)0.3 (0.2–0.5)1.6 (1.5–1.8)1.6 (1.6–1.7)3.2 (2.7–3.7)3.6 (2.5–4.8)5.0 (3.9–6.0)
E. faecalis 0.5 (0.5–0.5)0.4 (0.3–0.4)1.0 (0.5–1.5)0.5 (0.5–0.5)1.4 (0.8–1.9)0.8 (0.7–1.0)1.6 (1.2–2.1)
Meth-S S. aureus 2.0 (1.7–2.2)0.75 (0–1.5)2.3 (2.0–2.6)0.3 (0.1–0.5)3.3 (3.2–3.4)0.4 (0.3–0.5)3.8 (3.6–4.0)
Meth-R Cipro-S S. aureus 1.2 (0.8–1.6)0.4 (0.4–0.5)2.0 (1.3–2.7)0.6 (0.5–0.7)2.4 (2.0–2.7)0.7 (0.7–0.7)3.7 (3.6–3.8)
Meth-R Cipro-R S. aureus 1.0 (1.0–1.0)0 (0–0)0 (1.0–1.0)0 (0–0)1.3 (1.1–1.5)0.3 (0–0.6)2.3 (2.1–2.5)
E. coli 4.8 (4.7–4.8)2.4 (1.9–2.8)≥9.4 (9.4–≥9.6)≥9.6 (≥9.6)≥9.6 (≥9.6)≥9.6 (≥9.6)≥9.6 (≥9.6)
P. aeruginosa 2.2 (2.0–2.4)1.0 (0.9–1.2)2.8 (2.4–3.2)1.2 (0.9–1.6)4.3 (3.9–4.7)1.9 (1.5–2.3)4.4 (4.0–4.7)
  • a Pen, penicillin; Meth, methicillin; Cipro, ciprofloxacin; S, susceptible; I, intermediate; R, resistant.

  • b Means of results from two separate experiments. Strains were exposed to concentrations 4 or 10 times the MICs (see the text) for 1 h at 35°C. Drug was removed by dilution to 1:1,000. SME indicates strains not previously exposed to gatifloxacin. PA-SME indicates strains previously exposed to gatifloxacin.