In vitro suspectibility of mycobacterium tuberculosis to azithromycin

Abstract

There are a number of new drugs that have been evaluated in children and adults for activity against tuberculosis. The¬se include amikacin, quinolones, rifamycin derivatives, clofazimine, beta-lactams and macrolides. We investigated the effi¬ciency of azithromycin, a new macrolide antibiotic, against Mycobacterium tuberculosis in vitro. Forty-three isolates of Mycobacterium tuberculosis were tested by standard proportion method on Lowenstein-Jensen medium containing 0.25, 0.5, 1.0, 2.0 and 4.0 mg/l of azithromycin. Cultures were evaluated after three or four weeks of incubation at 37° C. Azith¬romycin at concentration of 0.25 mg/l inhibited 38 of 43 strains, similarly 0.5, 1.0 and 2.0 mg/l inhibited 39 of 43 strains and 4.0 mg/l inhibited 40 of 43 strains . Three of 43 strains were resistant to rifampin. Two of this three were also resistant to azithromycin in all drug concentrations. One strain was also resistant to azithromycin in 0.25 mg/l concentration. The other one strain was only resistant to streptomycin. Our results showed that azithromycin was effective against Mycobac¬terium tuberculosis in vitro.