First- and second-line anti-tuberculosis drug resistance in Northwest Ethiopia

SETTING: Gondar Hospital, Gondar Health Centre, Metemma Hospital, Bahir Dar Hospital and Debre Markos Hospital in Northwest Ethiopia. OBJECTIVE: To assess the level of and risk factors for first- and second-line drug resistance among tuberculosis (TB) patients. DESIGN: Drug susceptibility testing (DST) against first-line drugs, including isoniazid (INH), rifampicin (RMP), streptomycin (SM), ethambutol (EMB) and pyrazinamide (PZA), was performed using the BacT/ALERT 3D system. DST against second-line drugs, including fluoroquinolones and aminoglycocides/cyclic peptides, was performed using GenoType MTBDRsl. RESULTS: Of 260 Mycobacterium tuberculosis isolates, 41 (15.8%) were resistant to at least one first-line drug, 13 (5.0%) were multidrug-resistant (MDR) and 9 (3.5%) were resistant to all first-line drugs. Any resistance to INH, RMP, SM, EMB and PZA was respectively 36 (13.8%), 15 (5.8%), 26 (10.0%), 19 (7.3%) and 12 (4.6%). Of 214 new and 46 previously treated cases, respectively 8 (3.7%) and 5 (10.9%) were MDR. All isolates were susceptible to all second-line drugs. CONCLUSION: A substantial number of new and previously treated cases harbour MDR-TB. We recommend DST at least for previously treated cases, patients who remain smear-positive at the end of the second month of treatment and patients in close contact with MDR-TB cases. Improved infection control measures need to be implemented in Ethiopia.