title: In vitro activity of moxifloxacin, a new 8-methoxyquinolone, against gram-positive bacteria.
abstract: The in vitro activity of moxifloxacin, formerly BAY 12-8039, against gram-positive bacteria was tested by the agar dilution method. A total of 189 isolates that included Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, streptococci, rhodococci, leuconostocs, pediococci, lactobacilli, and diphtheroids were tested. Moxifloxacin showed greater potency than ciprofloxacin against S. aureus, streptococci, and enterococci, having Minimal Inhibitory Concentrations (MICs) lower than those of ciprofloxacin by 2- to 64-fold. This improved activity was most prominent for S. aureus. Moxifloxacin was active against Leuconostoc and Rhodococcus species. Time-kill studies using moxifloxacin at a concentration of 3 micrograms/mL against one isolate each of methicillin-resistant S. aureus (MSSA) (MIC, 0.031 microgram/mL), MRSA (MIC, 1 microgram/mL), two isolates of E. faecalis (MICs, 0.25 and 2 micrograms/mL), and two isolates of vancomycin-resistant E. faecium (MICs, 0.25 and 2 micrograms/mL) revealed an average decrease in colony forming unit (CFU) by 3.8, 0.4, 4.0, 2.0, 4.2, and 1.8 log10 CFU/mL at 24 h, respectively. Moxifloxacin is a new 8-methoxyquinolone with improved in vitro activity against gram-positive bacteria. Further studies of the in vivo activity of this compound appear warranted.
authors.affiliation: Department of Internal Medicine, University of Texas Medical School at Houston 77030, USA.
authors.forename: K
authors.initials: K
authors.lastname: Malathum
authors.forename: K V
authors.initials: KV
authors.lastname: Singh
authors.forename: B E
authors.initials: BE
authors.lastname: Murray
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001372:Aza Compounds; D024841:Fluoroquinolones; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D011804:Quinolines
chemical_list: D000890:Anti-Infective Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D000077266:Moxifloxacin