0973-7510 Journal of Pure and Applied Microbiology 2581-690X DR. M.N. Khan 10.22207/JPAM.15.1.01 Additional Resistance to any Fluoroquinolones among Multidrug-resistant Mycobacterium tuberculosis Isolates from North Coastal Andhra Pradesh, India Suresh Kancharla Vimala Yapadinna Mohan Nitin Jyothi Padmaja Indugula Department of Microbiology, GITAM institute of Science, GITAM (Deemed to be University), Gandhinagar campus, Rushikonda, Visakhapatnam - 530 045, Andhra Pradesh, India. Department of Microbiology, GITAM Institute of Medical Sciences and Research, GITAM (Deemed to be University), Gandhinagar campus, Rushikonda, Visakhapatnam - 530 045, Andhra Pradesh, India. 25 01 2021 15 1 68 74 Copyright © 2021 The Author(s) 2021 This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.https://creativecommons.org/licenses/by/4.0/

Fluoroquinolones (FQ) are integral part of multidrug resistant/rifampicin resistant tuberculosis (MDR-TB/RR TB) treatment regimens. FQ resistance in MDR-TB lead to narrower treatment options and poor treatment outcomes. Hence proportion of FQ resistance among MDR-TB and cross-resistance among FQ in MDR-TB isolates was studied. This is the first study from North Coastal Andhra Pradesh, India. A cross-sectional study was conducted on 21,474 sputum samples from January-December 2018 and 833 culture isolates (rifampicin resistant detected by GeneXpert MTB / RIF assay and MDR-TB detected by direct and indirect GenoType MTBDRplus Assay) were analysed for FQ resistance by Mycobacterium Growth Indicator Tube (MGIT) for ofloxacin (Ofx) 2.0 µg/mL, levofloxacin (Lfx) 1.5 µg/mL and moxifloxacin (Mfx) 2.0 μg/mL. Among 833 culture isolates, 119 (14.2%) showed resistance to FQ which included 90 (10.8%) Ofx and Lfx resistance isolates but still sensitive to Mfx, 16 (1.92%) with resistance to all FQ tested, 12 Ofx monoresistance and 1 Lfx monoresistance. Mfx monoresistance was absent. Mfx sensitive isolates are 714 (85.7%) and were always sensitive to Ofx and Lfx. Cross-resistance was not complete. MDR-TB/RR TB is 4.1% among all TB patients. Additional resistance to FQ, among MDR-TB patients was seen in 14.2% patients.

Keywords Multidrug-resistant tuberculosis fluoroquinolones MGIT 960 cross-resistance