High degree of fluoroquinolone resistance among extrapulmonary tuberculosis patients at a tertiary care center in North India

Background: The treatment of drug-resistant tuberculosis (TB) involves various regimens. Among them, the most promising antibiotic regimens are fluoroquinolone (FQ) drugs. Drug susceptibility testing (DST) for FQs is not included as routine assessment for baseline TB diagnosis. Limited resources are available about FQ resistance among extrapulmonary TB (EPTB) cases. Methods: A total of 447 culture-positive specimens were subjected to DST for first-line anti-TB drugs (FLDs) and second-line anti-TB drugs. DST was performed using automated mycobacterium growth indicator tube-960 liquid culture techniques. The study was carried out during the period of April 2016 to March 2017. In addition, DST of FQs was also performed in FLD-sensitive strains. Results: Mycobacterium tuberculosis was isolated from 447 specimens. Of the 447 culture-positive EPTB specimens, 54 were rifampicin-resistant (RR)/multidrug-resistant TB (MDR-TB) isolates, 45 isolates were resistant to any drug, and the remaining 348 were sensitive to FLDs. Monoresistance of FQs was observed in 20.4% (11/54) among RR/MDR-TB isolates and 4.3% (15/348) among FLD-sensitive isolates. Conclusion: The high degree of FQ resistance observed in EPTB specimens among drug-sensitive and MDR-TB isolates is alarming. This study reflects the need to expand culture and DST for EPTB cases and include FQs within first-line DST in such settings. Furthermore, there should be a rational use of FQs for the treatment of other diseases.