AZITHROMYCIN ACTIVITY AGAINST MYCOBACTERIUM-AVIUM COMPLEX LUNG-DISEASE IN PATIENTS WHO WERE NOT INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS

We initiated a prospective trial of an azithromycin-containing regimen for the treatment of human immunodeficiency virus-negative patients w ith Mycobacterium avium complex (MAC) lung disease; the initial 4 mont hs of therapy were with azithromycin (600 mg/d) alone, The primary stu dy endpoint was microbiological response measured at 4 and 6 months of therapy. Of 29 patients enrolled in the study, 23 completed therapy. Fifty-two percent of these 23 patients were male, and 65% were smokers . All 23 patients were older than 45 years of age; 83% had bilateral d isease, and 48% had fibrocavitary disease. Macrolide (clarithromycin)- susceptible MAC isolates were recovered from these 23 patients before treatment, Cultures of sputum from 38% of these patients became negati ve, and the positivity of cultures of sputum from 76% of these patient s was significantly reduced. Sixty-eight percent of sputum cultures we re strongly positive (>200 colonies) before therapy, while only 27% we re strongly positive after therapy, Although most patients continued t o receive 600 mg of azithromycin/d, the high incidence of gastrointest inal side effects (76%) and altered hearing (41%) suggests the need fo r lower or less frequent dosing, Macrolide (clarithromycin) resistance did not develop in any MAC isolates during monotherapy, These results , which demonstrate that azithromycin is active against MAC pulmonary disease, provide a rationale to include this drug in the initial multi drug regimens recommended for the treatment of this disease.