High risk of drug-resistant tuberculosis when first-line therapy fails in a high HIV prevalence setting.

SETTING: Lesotho national multidrug-resistant tuberculosis (MDR-TB) program. OBJECTIVE: To determine the prevalence of drug-resistant TB (DR-TB) among patients registered for MDR-TB treatment after failure or suspected failure of the standard 6-month regimen for new TB patients (Category I). DESIGN: We conducted a retrospective cohort study of patients registered for MDR-TB treatment following failure or suspected failure of Category I. RESULTS: A total of 76 patients were included in the analysis, including 51 Category I treatment failures and 25 suspected Category I treatment failures. The prevalence of resistance to any drug was 92% among the treatment failures and 72% among the suspected failures. The proportion of MDR-TB was respectively 78% and 28% among the treatment failures and suspected failures. Among the subgroup of human immunodeficiency virus (HIV) positive patients, the proportion of MDR-TB was 84% among failures and 23% among suspected failures. CONCLUSION: DR-TB and MDR-TB were common among patients in whom Category I failed. Early initiation of empiric second-line anti-tuberculosis treatment while awaiting culture and drug susceptibility testing (DST) results should be considered for HIV-negative and -positive patients who have failed first-line anti-tuberculosis treatment; patients suspected to be failing a first-line regimen should undergo DST at the end of the intensive phase.