DRUG-RESISTANCE IN MYCOBACTERIUM-TUBERCULOSIS STRAINS ISOLATED FROM RETREATMENT CASES OF PULMONARY TUBERCULOSIS IN ETHIOPIA - SUSCEPTIBILITY TO FIRST-LINE AND ALTERNATIVE DRUGS

SETTING: Addis Ababa Tuberculosis Demonstration and Training Center, E thiopia.OBJECTIVES: To determine the pattern of drug resistance among re-treatment cases of pulmonary tuberculosis (TB), to determine the ri sk factors associated with multi-drug resistant (MDR) TB, and to propo se re-treatment regimens based on the patterns of susceptibility to fi rst-line and alternative drugs. DESIGN: One hundred and seven Mycobact erium tuberculosis strains isolated from an equal number of re-treatme nt cases of pulmonary TB were included in the study. Drug susceptibili ty was determined by the Bactec method. RESULTS: About 50% of the stra ins were resistant to one or more of the first-line drugs and 12% of t he strains were multi-drug resistant, i.e., resistant to both isoniazi d and rifampicin. Previous treatment with rifampicin was the most impo rtant predictor of MDR-TB. All MDR strains were susceptible to amikaci n, ciprofloxacin, ethambutol, ethionamide and clofazimine. CONCLUSION: The WHO re-treatment regimen would theoretically be effective for the treatment of all non-MDR-TB patients in this study. A proposed 12-mon th re-treatment regimen for MDR-TB patients would include a fluoroquin olone in combination with streptomycin, pyrazinamide, isoniazid, etham butol and clofazimine. There is an urgent need for more research to de fine safe and inexpensive treatment regimens for MDR-TB patients in lo w-income countries.