[Intra-macrophagic activity of antibiotics combinations against Mycobacterium marinum]

Fourteen strains of Mycobacterium marinum were isolated from patients with granulomatous skin lesion. All the strains were resistant to isoniazid and pyrazinamid and five resistant to rifampicin. The following antibiotics are used alone or in combination: ethambutol, rifabutin, ciprofloxacin, temafloxacin, erythromycin, clarithromycin, minocyclin. Minimal inhibitory concentrations are evaluated using agar dilution method. After what, activity of antibiotics against Mycobacterium marinum strains within human macrophages in investigated. After treating the monolayers at 24 and 96 h, a bactericidal effect is observed with rifabutin, ciprofloxacin, temafloxacin, clarithromycin and minocyclin. Combinations of ciprofloxacin, temafloxacin or clarithromycin with ethambutol and rifabutin produced synergistic effect.