THE ACTIVITY OF THE METHYLPIPERAZINYL FLUOROQUINOLONE CG-5501 - A COMPARISON WITH OTHER FLUOROQUINOLONES

The in-vitro activity of CG 5501 against a wide range of recent clinic al isolates was compared with that of three fluoroquinolones. CG 5501 inhibited 90% of the species of the family Enterobacteriaceae at 0.5 m g/L or less, exceptions being Enterobacter spp. (MIC90 2 mg/L) and Ser ratia spp. (MIC90 4 mg/L). Ninety per cent of Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter spp. were inhibited by 16, 4 and 1 mg/L respectively. CG 5501 had high activity against Gram- positive cocci, 90% of staphylococci being inhibited at 2 mg/L. Methic illin-resistant Staphylococcus aureus strains were generally ciproflox acin-resistant yet were all susceptible to 4 mg/L or less of CG 5501. Isolates of Streptococcus pneumoniae were eight-fold more susceptible to CG 5501 (MIC90 0.5 mg/L) than to ciprofloxacin (MIC90 4 mg/L) and t he former had a similar activity to that of trovafloxacin and sparflox acin. Enterococcus faecalis was generally two- to four-fold more susce ptible to CG 5501 or trovafloxacin than to ciprofloxacin. CG 5501 and trovafloxacin had high activity against Bacteroides fragilis (MIC90 0. 25 mg/L). Five strains of Chlamydia sop. were inhibited by less than o r equal to 0.12 mg/L of CG 5501; sensitive and multiresistant strains of Mycobacterium tuberculosis were inhibited by less than or equal to 0.5 mg/L of CG 5501. The high activity and breadth of its antibacteria l spectrum suggests that CG 5501 should be useful in a wide range of c linical infections.