1999 Volume 47 Issue Supplement1 Pages 1-15
The in vitro and in vivo antibacterial activities of pazufloxacin mesilate (PZFX mesilate), anew injectable quinolone, were compared with those of ofloxacin (OFLX), ciprofloxacin (CPFX), imipenem (IPM), ceftazidime (CAZ), gentamicin (GM), and minocycline (MINO).
In gram-positive bacteria, the MIC90s of PZFX mesilate against Staphylococcus aureus and Staphylococcus epidermidis ranged from 0.25 to 4 μg/ml. The antibacterial activity of PZFX mesilate against methicillin-resistant S. aureus (MRSA) was the most potent (MIC90: 16 μg/ml) among the agentstested.
The antibacterial activity of PZFX mesilate against gram-negative bacteria including Enterobacteriaceae and IPM-and GM-resistant Pseudomonas aeruginosa was comparable to that of CPFX, and superior to that of the other agents.
When the MIC of PZFX mesilate for the parent strain was compared with the MIC of quinoloneresistant P. aeruginosa (nfxA, nfxB, nfxC and nalB), the increase in MIC for the nfxB mutant was lower than for the other mutants.
Uptake of PZFX mesilate by S. aureus was unaffected by the addition of carbonyl cyanide-m-chlorophenyl hydrazone (CCCP), in contrast to CPFX.
PZFX mesilate showed potent bactericidal activity in a short period, and it also showed a longer postantibiotic effect (PAE) at high drug concentrations and in short periods than the other agents.
PZFX mesilate showed a potent protective effect against systemic infection in mice caused by gram-positive and-negative bacteria, including MRSA, and IPM-, GM-resistant P. aeruginosa, which reflected its in vitro antibacterial activity. PZFX mesilate also showed a potent therapeutic effect against pulmonary and urinary infection in mice, that exceeded expectations based on the MIC.
