Prevalence of fluoroquinolone resistance in mycobacterium tuberculosis in a tertiary care hospital in India

INTRODUCTION: Fluoroquinolones(FQ) are important drugs in treatment of drug resistant tuberculosis. In recent years, there is increase in FQ resistance due to suboptimal use of second line drugs in drug resistant tuberculosis and misuse as empiric therapy for respiratory infections. It is common in India that a suspected community acquired pneumonia treated with monotherapy with FQ later turns out to be pulmonary tuberculosis. Such a short exposure can induce bacillary resistance to entire class of drugs. AIMS: To determine the prevalence of ciprofloxacin (CFX), levofloxacin(LFX) and moxifloxacin(MFX) resistance to Mycobacterium tuberculosis (MTB) METHOD: During the period Jan. 2011 to Dec. 2013, all samples (pulmonary: sputum, BAL and extrapulmonary:lymph node, pleural fluid, CSF etc) which were culture positive for MTB, were retrospectively analyzed to assess the prevalence of CFX, LFX and MXF. Samples were cultured for MTB by radiometric method (MB/BacT Mycobacterium Detection System). Sensitivity tests were performed by conventional method on L.J. medium RESULTS: Pattern of resistance Year culture +ve CFX LFX MFX 2011 170 10 (5.9%) 05 (2.9%) 05 (2.9%) 2012 163 06 (3.7%) 01 (0.6%) 03 (1.8%) 2013 137 04 (2.9%) 02 (1.4%) 10 (7.3%) Total 470 20 (4.2%) 08 (1.7%) 18 (3.8%) CONCLUSION: During three year period, resistance to CFX has fallen posibly due to reduced usage, but that of MXF has increased possibly due to increased usage. The overall resistance to these drugs is low. Caution is advised to avoid indiscriminate use of these drugs. REFERENCE: Agarwal et al: Increasing incidence of fluoroquinolone-resistant Mycobacterium Tuberculosis in Mumbai, India.Int.J.Tuberc. Lung Dis 2009; 13(1):79-83.