ACTIVITY OF 7 ANTIMICROBIAL AGENTS, ALONE AND IN COMBINATION, AGAINSTAIDS-ASSOCIATED ISOLATES OF MYCOBACTERIUM-AVIUM COMPLEX

The activity of seven antimicrobial agents (and five two-drug combinat ions and five three-drug combinations) was investigated against 37 cli nical isolates of Mycobacterium avium recovered from blood cultures of AIDS patients. The susceptibility tests were performed in Middlebrook 7H12 broth using a radiometric method. MICs of amikacin, ciprofloxaci n, clarithromycin, clofazimine, ethambutol, rifabutin and sparfloxacin were determined. Five antimicrobial agents were tested in combination with clarithromycin and also with clarithromycin plus amikacin to loo k for possible synergic activity. Synergic activity in combination wit h clarithromycin and with clarithromycin plus amikacin, was detected f or rifabutin (54% and 51% of isolates, respectively), clofazimine (38% and 35%), ethambutol (16% and 32%), ciprofloxacin (8% and 14%) and sp arfloxacin (3% and 8%). No antagonism was observed. We conclude that c larithromycin is an essential component in the chemotherapy of M. aviu m complex disease.