Second nationwide anti-tuberculosis drug resistance survey in Namibia

SETTING: Namibia ranks among the 30 high TB burden countries worldwide. Here, we report results of the second nationwide anti-TB drug resistance survey.OBJECTIVE: To assess the prevalence and trends of multidrug-resistant TB (MDR-TB) in Namibia.METHODS: From 2014 to 2015, patients with presumptive TB in all regions of Namibia had sputum subjected to mycobacterial culture and phenotypic drug susceptibility testing (DST) for rifampicin, isoniazid, ethambutol and streptomycin if positive on smear microscopy and/or Xpert MTB/RIF.RESULTS: Of the 4124 eligible for culture, 3279 (79.5%) had Mycobacterium tuberculosis isolated. 3126 (95%) had a first-line DST completed (2392 new patients, 699 previously treated patients, 35 with unknown treatment history). MDR-TB was detected in 4.5% (95%CI 3.7-5.4) of new patients, and 7.9% (95%CI 6.0-10.1) of individuals treated previously. MDR-TB was significantly associated with previous treatment (OR 1.8, 95%CI 1.3-2.5) but not with HIV infection, sex, age or other demographic factors. Prior treatment failure demonstrated the strongest association with MDR-TB (OR 17.6, 95%CI 5.3-58.7).CONCLUSION: The prevalence of MDR-TB among new TB patients in Namibia is high and, compared with the first drug resistance survey, has decreased significantly among those treated previously. Namibia should implement routine screening of drug resistance among all TB patients.