In-vitro activity of PD 117 596, a new quinolone, against bacterial isolates from cancer patients

The in-vitro activity of PD117 596, a new 4-quinolone antimicrobial agent was compared with that of ciprofloxacin against 798 Gram-positive and Gram-negative distinct isolates from cancer patients. PD117 596 was found to have a broad antimicrobial spectrum with excellent activity against the Enterobacteriaceae (MIC₉₀ 0.03 mg/l) Acinetobacter spp. (MIC₉₀ 0.25 mg/l), Aeromonas spp. (MIC₁₀₀ 0.06 mg/l) and Pseudomonas spp. including Ps.aeruginosa (MIC₉₀ 0.5 mg/l). It was also extremely active against Gram-positive micro-organisms particularly Staphylococcus spp. (including methicillin-resistant and coagulase-negative isolates) Bacillus spp. and streptococci. PD117 596 had lower minimal inhibitory concentrations against most isolates tested than ciprofloxacin, the most active currently available 4-quinolone.