IN VITRO ANTIBACTERIAL ACTIVITY, PENETRATION INTO SPUTUM, AND CLINICAL EVALUATION OF LEVOFLOXACIN IN CHRONIC RESPIRATORY-TRACT INFECTIONS

• Published in: CHEMOTHERAPY Vol. 40; no. 3; pp. 336 - 347
• Main Authors: Masaki, Hironori, Matsumoto, Keizo, Watanabe, Kiwao, Mitarai, Satoshi, Tao, Misao, Oishi, Kazunori, Terazono, Toshiaki, Yoshida, Toshiaki, Iwagaki, Akitaka, Nagatake, Tsuyoshi, Tanaka, Hirofumi, Degawa, Satoshi, Yamauchi, Soichiro, Yamamoto, Masashi, Ishikawa, Hidefumi, Shimogama, Seiji
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of Chemotherapy 1992
• Subjects: levofloxacin; Streptococcus pneumoniae
• ISSN: 0009-3165; 1884-5894
• DOI: 10.11250/chemotherapy1953.40.336

Levofloxacin (LVFX) is a newly developed antibacterial agent derived from fluorinated quinolone. We carried out laboratory and clinical studies to evaluate its usefulness in respiratory infections. Thein vitro antibacterial activity of LVFX against 240 isolates of 6 major respiratory pathogens was compared with that of other inhibitors of DNA gyrase. The MIC50 and MIC90 at 106 CFU/ml was 0.013μg/ml and 0.025μg/ml againstHaemophilus influenzae(33 strains), 0.78μg/ml and 1.56μg/ml againstStreptococcus pneumoniae(49 strains), 0.05μg/ml and 0.1μg/ml againstBranhamella catarrhalis(39 strains), 1.56μg/ml and 6.25μg/ml againstPseudomonas aeruginosa(48 strains), 1.56μg/ml and 50μg/ml againstStaphylococcus aureus(48 strains), 0.1μg/ml and 0.39μg/ml againstKlebsiella pneumoniae(23 strains). These MICs were the same as or better than the MICs of other inhibitors of DNA gyrase. The maximal concentrations in the sputum were 2.54μg/ml and 0.64μg/ml. The maximal concentrations in the sputum divided by the maximal concentrations in the serum were 51.4% and 54.2%. These results were almost as same as penetration of other inhibitors of DNA gyrase. Eight patients with 10 episodes of respiratory infection were studied for clinical evaluation of LVFX administered orally at a dose of 300mg or 600mg daily for 3-15 days. The causative organisms wereH. influenzae(4 strains), S. pneumoniae(2 strains), B. catarrhalis(3 strains) andP. aeruginosa(2 strains). The therapeutic efficacy was 88.8%. LVFX had higher antibacterial activity againstS. pneumoniae than the other inhibitors of DNA gyrase (ofloxacin, norfloxacin, and enoxacin). From these results we concluded that LVFX is an effective, useful, and safe oral antibacterial agent for the treatment of respiratory infections.