title: Excellent activity of newer quinolones on Legionella pneumophila in J774 macrophages.
abstract: The activity of six antibiotics directed against intracellularly multiplying Legionella pneumophilia was examined in tissue cultures with J774 macrophages. The drugs tested were the new quinolones, BAY Y 3118 and clinafloxacin, and ciprofloxacin, erythromycin, gentamicin and ampicillin served as reference drugs. Additionally, the MICs of these drugs against L. pneumophila were determined in vitro by broth microdilution. Despite their low MIC values, ampicillin and gentamicin did not inhibit intracellular multiplication of L. pneumophila in J774 macrophages. In contrast, an inhibition of intracellular growth could be demonstrated for the four other antibiotics. The new quinolones BAY Y 3118 and clinafloxacin showed the highest activity against intracellular L. pneumophila. At a concentration of 0.00078 mg/L already, a marked reduction in bacterial counts was seen for both drugs in comparison to the growth control without antibiotics. The corresponding effective concentrations were 0.0125 mg/L for ciprofloxacin and 0.2 mg/L for erythromycin. It may be concluded that new quinolone derivatives might become an alternative to erythromycin and rifampicin which at present are the drugs of primary choice for the treatment of legionnaires' disease.
authors.affiliation: Institute of Medical Microbiology and Hygiene, Klinikum Mannheim, University of Heidelberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Walz
authors.forename: T
authors.initials: T
authors.lastname: Nichterlein
authors.forename: H
authors.initials: H
authors.lastname: Hof
mesh_terms: D000667:Ampicillin / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D000890:Anti-Infective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001431:Bacteriological Techniques; D002939:Ciprofloxacin / Q000494:pharmacology / Q000627:therapeutic use; D015169:Colony Count, Microbial; D004917:Erythromycin / Q000494:pharmacology / Q000627:therapeutic use; D024841:Fluoroquinolones; D005839:Gentamicins / Q000494:pharmacology / Q000627:therapeutic use; D016952:Legionella pneumophila / Q000187:drug effects* / Q000254:growth & development; D007877:Legionnaires' Disease / Q000188:drug therapy*; D008264:Macrophages; D051379:Mice; D010406:Penicillins / Q000494:pharmacology / Q000627:therapeutic use; D015363:Quinolones / Q000494:pharmacology / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D005839:Gentamicins; D010406:Penicillins; D015363:Quinolones; C079807:Bay Y3118; D002939:Ciprofloxacin; D004917:Erythromycin; D000667:Ampicillin; C057477:clinafloxacin