Should we stop using fluoroquinolone in non-tuberculosis patients? A study to assess the drug resistance profile of rifampicin-resistant pulmonary tuberculosis

Objectives One of the biggest challenges that nations with high tuberculosis (TB) prevalence, especially India, are facing is drug-resistant TB. Fluoroquinolones (FQs) play an essential role in treating & controlling drug-resistant tuberculosis (DR-TB). Missense mutations found within the FQ resistance-determining region of the Mycobacterial genome pose a significant barrier to treatment, prognosis, and elimination of TB. So, knowledge of FQs resistance data from high TB-burden countries becomes crucial. Material and Methods This retrospective observational research was performed at the Nodal DR-TB Centre in Northern India. All newly diagnosed patients with pulmonary rifampicin-resistant tuberculosis (RR-TB), using morning sputum samples, from January 2021 to December 2023, were recruited for the research. Sputum samples from RR-TB patients were subsequently assessed by employing line probe assay (LPA) for detection of additional drug resistance to isoniazid (INH), FQs, as well as second-line injectables (SLI). This data was used to estimate the proportion of different combinations of anti-TB drug resistance among RR-TB patients. Results The research recruited 607 patients diagnosed with pulmonary RR-TB, identified through the cartridge-based nucleic acid amplification test (CB-NAAT) of sputum samples. Out of these 607 patients, first- and second-line LPA tests revealed that INH resistance was present in 477 patients (78.5%) and FQs resistance (either Levofloxacin or Moxifloxacin or both) was present in 352 (57.9%) patients. On further determination of different combinations of drug resistance, we found that rifampicin-INH resistance was present in 158 (26%), rifampicin-INH-FQs resistance in 240 (39.5%), Rifampicin-INH-FQs-SLI resistance in 89 (13%) patients. Conclusion A large number of the patients of RR-TB had additional resistance to isoniazid and FQs, to the extent that may jeopardize the national efforts of TB elimination. It also questions the rampant use of FQs for non-TB indications, leading to an unacceptably high proportion of FQ resistance.