The bactericidal activity of gatifloxacin in plasma and urine

Abstract

Objective: To investigate the bactericidal activity of gatifloxacin in serum and urine against relevant pathogens. Methods: Serum and urine samples obtained in a single rising dose pharmacokinetic study were investigated for bactericidal activity. The doses employed were placebo, and 200, 400, 600 and 800 mg of gatifloxacin. Results: The titers obtained reflected the dose and susceptibility of the pathogen. In serum a titer of ≤ 1:8 was observed for Escherichia coli for > 24 h after 400 mg; for Staphylococcus aureus and Acinelobacter baumanii the titer was ≤ 1:8 for between 12-24 h after 600 mg; for Serratia marcescens it was ≤ 1:8 for > 12 h following 800 mg; and for Streptococcus pneumoniae it was ≤ 1:8 for 8 h following 800 mg. In urine, the titers were greater, and for Escherichia coli, Staphylococcus saprophyticus, Proteus mirabilis and Enterococcus faecalis the titer was > 1:8 for 12-24 h after 200 mg and for 24-36 h after a 400-mg dose. Pseudomonas aeruginosa demonstrated a titer of > 1:8 for 18-24 h following 600 mg. Conclusions: These data suggest that gatifloxacin should be efficacious for a wide range of systemic and urinary tract infections.