Drug resistance and associated genetic mutations among patients with suspected MDR-TB in Uttar Pradesh, India.

SETTING

Programmatic Management of Drug-Resistant Tuberculosis (PMDT) programme in 32 districts of Uttar Pradesh (UP), India.

OBJECTIVE

To provide epidemiological status of multidrug-resistant tuberculosis (MDR-TB) and associated microbial genetic mutations among suspected cases in UP.

DESIGN

We retrospectively studied and tested using line-probe assay (LPA) 4895 retreatment patients with suspected MDR-TB who were enrolled for PMDT during 2012-2015. The demographic characteristics of cases, LPA-determined drug resistance, the genetic mutation profile, trends in drug resistance over the study period as well as the comparative performance of LPA and phenotypic drug susceptibility testing (DST) were analysed.

RESULTS

MDR-TB and rifampicin-resistant TB (RR-TB) were confirmed in respectively 34.5% and 40.3% cases. The RR-TB detection rate (a valid proxy for MDR-TB) initially declined during the study period. Age ⩿30 years and implemented MDR-TB suspicion criteria were independent predictors for RR-TB (P < 0.01). LPA indicated predominant distribution of S531L (1483/1970, 75.3%) and S315T1 (1981/2116, 93.6%) mutations in the rpoB and katG genes, respectively, and had >94.0% agreement with phenotypic DST in determining rifampicin/isoniazid resistance.

CONCLUSION

MDR-TB prevalence in retreatment cases is very high, highlighting the need to reduce the development and transmission of drug-resistant TB.