ABSTRACT
INTRODUCTION: The burden of MDR-TB is unknown in areas that do not have drug susceptibility testing (DST), but its frequency is expected to be higher in previously treated cases. Where DST is not available the WHO recommended standardized retreatment (Category II) regimen is given to previously treated TB patients OBJECTIVE: To evaluate the frequency and pattern of drug resistance of Mycobacterium tuberculosis isolated from patients with chronic smear positive pulmonary tuberculosis. METHOD: We conducted a retrospective review of mycobacterial cultures and drug susceptibility testing (DST) performed on sputum samples collected, between January 2005 and September 2006, from 40 patients with pulmonary TB who had failed at least one standard retreatment regimen. Clinical data was extracted from patients' case notes. RESULTS: M. tuberculosis was recovered from 28 (70%) of the 40 patients. Of the 28 culture positive cases, 10 (36%) had resistance to at least rifampicin and isoniazid (multi-drug resistant TB), 22 (79%) isolates had resistance to streptomycin and 13 (46%) to ethambutol. Of the patients with a positive culture, only one (3.6%) had a fully susceptible organism. Of the 10 patients with MDR TB, 7 had received two or more retreatment courses. CONCLUSION: The frequency of drug resistant TB was high among patients who failed at least one course of category II therapy. Effective combination regimens based on DST is necessary in patients who remain smear positive on the standardized retreatment regimen.
ABSTRACT
BACKGROUND: The level of drug resistance in mycobacterial isolates from previously treated cases in Ghana is not known although drug resistant tuberculosis threatens efforts to control the disease. OBJECTIVE: To identify and determine the susceptibility of mycobacterial isolates from tuberculosis cases with clinical treatment failure. METHODS: This prospective survey was undertaken at the Chest Clinic of Korle Bu Teaching Hospital in Accra, Ghana. The participants were twenty-eight cases referred to the hospital with clinical treatment failure. Two sputum specimens from each case were stained by Ziehl-Neelsen method, cultured, identified and sensitivity tests performed by the proportion method. RESULTS: Eighteen isolates of mycobacteria were identified from 28 failed treatment cases. Five were atypical mycobacteria. Approximately fifty percent (13/28) of cases had Mycobacterium tuberculosis, 5(18%) had atypical mycobacteria, 7(25%) had pure fungal growth and 3(11% 8) had no growth. Fifteen isolates were resistant to two or more drugs, of which 6 were resistant to all four drugs tested. CONCLUSION: Continuous drug resistance monitoring must be instituted as part of the tuberculosis control programme.
