Fluoroquinolone susceptibility in first-line drug-susceptible M. tuberculosis isolates in Lima, Peru

To determine at two distinct time points the prevalence of resistance to ofloxacin (OFX), the representative class drug of fluoroquinolones (FQs), in M. tuberculosis isolates susceptible to first-line drugs. There were 279 M. tuberculosis isolates from the two cohorts (2004-2005: 238 isolates; 2017: 41 isolates) that underwent OFX drug-susceptibility testing (critical concentration: 2 µg/ml). Of 238 isolates in Cohort 1, no resistance to OFX was detected (95% CI 0-0.016); likewise, in Cohort 2, no resistance to OFX was detected in 41 isolates (95% CI 0-0.086). Our findings suggest that FQ use remains a viable option for the treatment of first-line drug-susceptible TB in Peru.