Molecular Detection of Ofloxacin and Kanamycin Resistance in Patients with MDR and Non-MDR TB from Suburban Districts in Hangzhou, China, 2019–2020

The continuing emergence and spread of drug-resistant Mycobacterium tuberculosis complex (MTBC) poses a challenge to global tuberculosis (TB) control programs. Drug resistance in TB is mainly conferred by specific point mutations in the MTBC genome[1]. Multidrug-resistant TB (MDR-TB), which is caused by MTBC strains with resistance to both isoniazid and rifampicin (RIF), the most important first-line medicines, poses the main threat to TB control and elimination. Fluoroquinolones (FQs) and second-line injectable drugs (SLIDs) are core compounds in current MDR-TB treatment regimens[2]; however, data on the prevalence of resistance to FQs and SLIDs among MTBC strains has been lacking. The rapidly increasing number of DR-TB cases further underscores the need for more intensive surveillance of susceptibility to these important second-line drugs, to minimize further increases in the number of cases of preXDR-TB (MDR-TB with additional resistance to any FQ drug or at least one of the three SLIDs) and XDR-TB (MDR-TB with resistance to both FQs and SLIDs).