MINIMAL INHIBITORY CONCENTRATIONS OF SULBACTAM AMPICILLIN AGAINST DRUG-SENSITIVE AND DRUG-RESISTANT ISOLATES OF MYCOBACTERIUM-TUBERCULOSIS/

A total of 92 isolates of Mycobacterium tuberculosis consisting of equ al numbers of sensitive and resistant strains was tested for their sus ceptibility to sulbactam and ampicillin (in the ratio of 1:2) on Lowen stein-Jensen (LJ) and 7H11 agar media. The geometric mean MIC was 63.9 7 mu g/ml for the drug sensitive strains and 65.92 mu g/ml for the res istant strains, and the overall mean was 65.01 mu g/ml. The high MIC o n LJ medium could be attributed to the higher protein content which re sulted in greater binding of sulbactam/ampicillin. On the other hand, the geometric mean MIC on 7H11 medium was 26.73 mu g/ml for sensitive strains and 23.82 mu g/ml for resistant strains; the overall mean bein g 25.23 mu g/ml. Although these MICs of sulbactam-ampicillin are highe r than those reported earlier, they can be easily achieved in serum. F urther studies on experimental tuberculosis and in humans will be need ed to prove the efficacy of sulbactam/ampicillin in the treatment of p atients with multidrug resistant tuberculosis.