title: Sub-inhibitory and post-antibiotic effects of an optically active isomer of ofloxacin.
abstract: The sub-inhibitory and post-antibiotic suppressive effects of DR-3355, an optically active isomer (S-(-) form) of (+/-)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methylpiperazin-1-yl)-7- oxo-7H- pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid (ofloxacin) were compared with those of ofloxacin, ciprofloxacin and ceftazidime by observing changes in bacterial multiplication and morphology in vitro. DR-3355 affected the proliferation of Staphylococcus aureus E46, Escherichia coli E77156 and Pseudomonas aeruginosa PI-III at 1/4 to 1/2 times the minimal inhibitory concentration (MIC) for each strain. The compound also affected the morphology of these strains at 1/32 times the MICs. Upon MIC basis, these sub-inhibitory effects of DR-3355 were almost identical to those of the reference compounds. On the other hand, exposure of E. coli to 1 and 4 times the MIC of DR-3355 for 3 h produced post-antibiotic effects of 0.7 and 1.9 h, respectively, and the effects of the compound were almost equal to those of ofloxacin and ciprofloxacin and much greater than that of ceftazidime.
authors.affiliation: Research Institute, Daiichi Seiyaku Co., Ltd., Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Une
authors.forename: Y
authors.initials: Y
authors.lastname: Osada
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000648:ultrastructure; D004926:Escherichia coli / Q000187:drug effects / Q000648:ultrastructure; D007536:Isomerism; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D015242:Ofloxacin / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000648:ultrastructure; D013211:Staphylococcus aureus / Q000187:drug effects / Q000648:ultrastructure
chemical_list: D015242:Ofloxacin