Tuberculosis drug resistance in Southern Mozambique: results of a population-level survey in the district of Manhiça.

SETTING: Mozambique, one of the world's high tuberculosis (TB) burden countries, has conducted only one national-level drug resistance survey, in 2007-2008.

OBJECTIVE: To determine the drug resistance patterns of laboratory-confirmed TB cases.

DESIGN: This was a population-level survey conducted over a 1-year period in the district of Manhiça. All laboratory-confirmed cases were evaluated for first-line anti-tuberculosis drug susceptibility testing using liquid culture.

RESULTS: Resistance to at least one first-line drug was observed in 44 of 276 isolates (15.9%). Prevalence of drug resistance to each of the five anti-tuberculosis drugs tested was 4.0% for streptomycin, 10.1% for isoniazid (INH), 6.2% for rifampicin, 3.6% for ethambutol and 1.1% for pyrazinamide. The overall prevalence of multidrug-resistant TB (MDR-TB) was 5.1%: 3.8% (95%CI 2.0-7.0) in new and 13.2% (95%CI 5.8-27.3) in retreatment cases. Respectively 4.6% and 2.6% of new and retreatment cases were INH-monoresistant. Previous history of anti-tuberculosis treatment was associated with having MDR-TB (OR 4.3, 95%CI 1.3-14.1).

CONCLUSION: The prevalence of drug resistance in the district of Manhiça is slightly higher than, but still compatible with, previous national estimates. INH monoresistance was high, posing the risk of hidden monotherapy in the continuation phase.