2003 Volume 51 Issue 5 Pages 300-305
We studied the development of resistance to pazufloxacin (PZFX) and ciprofolxacin (CPFX) in Staphylococcus aureus using a model simulating the serum level after drip infusion of PZFX mesilate and CPFX hydrochloride in humans, obtaining the following results:
1) In the model simulating the serum level after drip infusion of PZFX mesilate (500mg) or CPFX hydrochloride (300mg), PZFX mesilate showed greater bactericidal activity, reflected AUC/MIC and Cmax/MIC.
2) From the population analysis using culture broth after the CPFX simulation model, CPFX-resistant subpopulations were detected at concentrations of 1-4μg/mL and 10-40μg/mL. No obvious PZFX-resistant subpopulations were detected in the PZFX simulation model.
3) MICs of CPFX against isolates from culture broth after the CPFX simulation model increased 4-to 32-fold and additional amino acid changes were seen in DNA gyrase in isolates with MICs increased over 4-fold. No differences were in seen MICs between isolates from culture broth after the PZFX simulation model and the parent strain and no additional amino acid changes were seen in either DNA gyrase or topoisomerase IV.
