Table 3.

Influence of pH and Ca2+ and Mg2+cations on the MICs of ciprofloxacin and sparfloxacin

Strain and drugMIC [μg/ml (fold increase)] in brotha at pH:
8.0 (MHB-A)7.25.8 (MHB-A)
MHB-AMHB-BMHB-CMHB-D
E. coli NIHJ JC-2
 Ciprofloxacin0.0160.031 (2)0.031 (2)0.063 (4)0.063 (4)0.125 (8)
 Sparfloxacin0.0080.031 (4)0.031 (4)0.063 (8)0.063 (8)0.25 (31)
P. aeruginosa ATCC 27853
 Ciprofloxacin0.500.50 (1)0.50 (1)0.50 (1)1 (2)2 (4)
 Sparfloxacin0.502 (4)2 (4)4 (8)4 (8)8 (16)
  • a MHB-A, MHB with concentrations of Ca2+ and Mg2+ of 25 and 12.5 mg/liter, respectively; MHB-B, MHB with concentrations of Ca2+ and Mg2+ of 50 and 25 mg/liter, respectively; MHB-C, MHB with concentrations of Ca2+ and Mg2+ of 125 and 62.5 mg/liter, respectively; MHB-D, MHB with concentrations of Ca2+ and Mg2+ of 250 and 125 mg/liter, respectively.