In-vitro activity of PD 117558, a new quinolone against bacterial isolates from cancer patients.

The in-vitro activity of PD 117558, a new quinolone antimicrobial agent, was compared to that of four other quinolones, imipenem and ceftazidime against a variety of Gram-positive and Gram-negative isolates from cancer patients. PD 117558 was found to have a broad antimicrobial spectrum with excellent activity against all Gram-positive isolates (including methicillin-resistant Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus faecalis and Group JK-corynebacteria). It was also extremely active against Gram-negative bacilli with the exception of Pseudomonas aeruginosa against which ciprofloxacin was more active. Fleroxacin was slightly less active and S-25930 and S-25932 considerably less active than PD 117558. PD 117558 also had lower minimal inhibitory concentrations for most organisms tested than either imipenem or ceftazidime.