title: In vitro and in vivo activities of novel fluoroquinolones alone and in combination with clarithromycin against clinically isolated Mycobacterium avium complex strains in Japan.
abstract: The recommended treatments for Mycobacterium avium complex (MAC) infectious disease are combination regimens of clarithromycin (CLR) or azithromycin with ethambutol and rifamycin. However, these chemotherapy regimens are sometimes unsuccessful. Recently developed antimicrobial agents, such as newer fluoroquinolones (FQs) containing C-8 methoxy quinolone (moxifloxacin [MXF] and gatifloxacin [GAT]), are expected to be novel antimycobacterial agents. Here, we evaluated the in vitro and in vivo antimycobacterial activities of three FQs (MXF, GAT, and levofloxacin) and CLR against clinically isolated MAC strains. Subsequently, the in vitro and in vivo synergic activities of FQ-CLR combinations against MAC strains were investigated. CLR and the individual FQs alone showed promising activity against MAC strains in vitro, and the bacterial counts in organs (lungs, liver, and spleen) of MAC-infected mice treated with single agents were significantly reduced compared to control mice. CLR showed the best anti-MAC effect in vivo. When the three FQs were individually combined with CLR in vitro, mild antagonism was observed for 53 to 57% of the tested isolates. Moreover, mice were infected with MAC strains showing mild antagonism for FQ-CLR combinations in vitro, and the anti-MAC effects of the FQ-CLR combinations were evaluated by counting the viable bacteria in their organs and by histopathological examination after 28 days of treatment. Several FQ-CLR combinations exhibited bacterial counts in organs significantly higher than those in mice treated with CLR alone. Our results indicate that the activity of CLR is occasionally attenuated by combination with an FQ both in vitro and in vivo and that this effect seems to be MAC strain dependent. Careful combination chemotherapy using these agents against MAC infectious disease may be required.
authors: Second Department of Internal Medicine, Nagasaki University School of Medicine and Dentistry, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan.
authors: Yoshihisa
authors: Y
authors: Kohno
authors: Hideaki
authors: H
authors: Ohno
authors: Yoshitsugu
authors: Y
authors: Miyazaki
authors: Yasuhito
authors: Y
authors: Higashiyama
authors: Katsunori
authors: K
authors: Yanagihara
authors: Yoichi
authors: Y
authors: Hirakata
authors: Kiyoyasu
authors: K
authors: Fukushima
authors: Shigeru
authors: S
authors: Kohno
mesh_terms: D000818:Animals; D001372:Aza Compounds / Q000494:pharmacology / Q000627:therapeutic use; D017291:Clarithromycin / Q000494:pharmacology* / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D024841:Fluoroquinolones / Q000494:pharmacology* / Q000627:therapeutic use; D000077734:Gatifloxacin; D006801:Humans; D007564:Japan; D064704:Levofloxacin; D008099:Liver / Q000187:drug effects / Q000382:microbiology; D008168:Lung / Q000187:drug effects / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D000077266:Moxifloxacin; D015269:Mycobacterium avium Complex / Q000187:drug effects*; D015270:Mycobacterium avium-intracellulare Infection / Q000188:drug therapy* / Q000382:microbiology; D015242:Ofloxacin / Q000494:pharmacology / Q000627:therapeutic use; D011804:Quinolines / Q000494:pharmacology / Q000627:therapeutic use; D013154:Spleen / Q000187:drug effects / Q000382:microbiology
chemical_list: D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D064704:Levofloxacin; D015242:Ofloxacin; D017291:Clarithromycin; D000077734:Gatifloxacin; D000077266:Moxifloxacin
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