Background: Between 2009 and 2013, there was a worldwide increase in cases of multidrug-resistant tuberculosis (MDR-TB) and the extension of resistance to second-line antibiotics for cases of extensively resistant tuberculosis (TB-XDR). Studies in Mozambique regarding the resistance of Mycobacterium tuberculosis to second-line antibiotics are scarce. The objective of the study was to evaluate the resistance profile of M. tuberculosis to second-line antibiotics in samples that were referred to the National Reference Laboratory of Tuberculosis in Maputo in the period from 2011 to 2015.

Methods: A retrospective, descriptive, cross-sectional study was conducted. Data from 2011 to 2015 were collected from the database of National Reference Laboratory of Tuberculosis. The data were selected from samples submitted to the second-line antibiotic susceptibility testing (AST). For the univariate analysis of data, the descriptive statistics were used to elaborate the frequency tables. Bivariate analysis was performed using the chi-square test at 5% significance to verify the association between resistance to second-line antibiotics and treatment history.

Results: Of the 4,116 isolates of M. tuberculosis from 2011 to 2015, only 451 were submitted to the second line AST of which approximately 71% (322/451) were TB- MDR. About 36% (161/451) of isolates were resistant to the second line antibiotics. 21.7% (70/322) of the MDR-TB cases were Pre-Extensively Tuberculosis Resistant (TB-Pre-XDR) and 21.4% (69/322) were XDR-TB. The combination of Amikacin + Kanamycin + Capreomycin + Ofloxacin predominated with 12.4% (56/451), whilst 12.2% (55/451) were MDR-TB. The History of treatment was significantly associated with resistance to Ofloxacin.

Conclusion: Resistance to second-line antibiotics was common in MR-TB patients and most frequent for the treatment combination of Amikacin + Kanamycin + Capreomycin + Ofloxacin.

Keywords: Tuberculosis; MDR-TB; Second-line anti-tuberculosis drugs