Additional Resistance to Moxifloxacin and Levofloxacin among MDR-TB Patients with Base Line Resistance to Ofloxacin at a Reference Laboratory

Fluoroquinolones are among the most promising antibiotic drugs for Tuberculosis treatment. Although high levels of fluoroquinolone resistance have been detected among many common bacterial pathogens, little is known about the fluoroquinolone resistance of M. tuberculosis especially at the baseline. The present study was thus aimed at determining the profile of resistance against two newer generation fluoroquinolones-Moxifloxacin and Levofloxacin in MDR-TB isolates with baseline resistance to ofloxacin. A total number of 65 isolates (4 XDR and 61 pre-XDR) were subjected to susceptible testing against levofloxacin and two (higher and lower) concentrations of moxifloxacin. 72.3% in addition to being resistant to ofloxacin were also resistant to levofloxacin and lower concentration of moxifloxacin. The increasing use of FQs for the treatment of other bacterial infections has led to increasing resistance to these antimicrobials. Newer generation FQs are promising drugs in the treatment of drugresistant Tuberculosis but care should be taken regarding the rationale use of these drugs for the treatment of other diseases especially when other drugs are available.