Additional Resistance to any Fluoroquinolones among Multidrug-resistant Mycobacterium tuberculosis Isolates from North Coastal Andhra Pradesh, India

Kancharla Suresh,Yapadinna Vimala,Indugula Jyothi Padmaja,Nitin Mohan

doi:10.22207/jpam.15.1.01

Abstract

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 & 833 culture isolates (rifampicin resistant detected by GeneXpert MTB / RIF assay & 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 & 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 & 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.

Highlights

Infection with Mycobacterium tuberculosis resistant to isoniazid (H) and rifampicin (R) called as MDR-TB or rifampicin resistance (RR) TB,[1,2,3] leads to treatment with less potent, more toxic and expensive second-line anti-TB drugs (SLD)
A cross-sectional study was conducted on 21,474 sputum samples from January-December 2018 & 833 culture isolates were analysed for FQ resistance by Mycobacterium Growth Indicator Tube (MGIT) for ofloxacin (Ofx) 2.0 μg/mL, levofloxacin (Lfx) 1.5 μg/mL & moxifloxacin (Mfx) 2.0 μg/mL
Under the Revised National Tuberculosis Control Program (RNTCP) for India called as National Tuberculosis Elimination Programme (NTEP), universal drug susceptibility testing (DST) to at least R for all individuals diagnosed with TB through Cartridge Based Nucleic Acid Amplification Test (CBNAAT)/ GeneXpert MTB / RIF assay, available in district/CBNAAT laboratory which are WHO approved[2]

Summary

Introduction

Infection with Mycobacterium tuberculosis resistant to isoniazid (H) and rifampicin (R) called as MDR-TB or RR TB,[1,2,3] leads to treatment with less potent, more toxic and expensive second-line anti-TB drugs (SLD). FQ resistance and poor treatment outcomes in MDR-TB have been reported in studies[4,5]. India has high TB burden and is a high MDR-TB burden country,[6] and by inference harbours large extensively-drug resistant tuberculosis (XDR-TB) population. FQ resistance may be a more prevalent than reported and can threaten TB control programmes[1]. Studies from India have demonstrated the prevalence of FQ resistance in MDR-TB patients[1,3,7,8,9] but none from North Coastal Andhra Pradesh. We studied the proportion of FQ resistance among MDR-TB/RR-TB and the proportion of their cross‐resistance among MDR-TB/RR-TB isolates

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Conclusion