Fluoroquinolones (FQs) are broad-spectrum second-line antimicrobial drugs commonly used in the treatment of tuberculosis (TB). Data on FQ resistance in the Khyber Pakhtunkhwa (KP) province of Pakistan, a high-burden country, are scarce. This study aimed to analyze the resistance to FQs in this specific geographic area. Samples were collected from 25 districts of KP from 2014 to 2019. Data regarding suspected TB patients were collected from their guardians or secondary caregivers. All the samples were subjected to decontamination and digestion processing. Drug susceptibility testing (DST) was performed according to the standard minimum inhibitory concentration for ofloxacin (OFX), levofloxacin (LEV), and moxifloxacin (MOX), taken as 2, 1, and 1 μg/mL, respectively. For the 5,759 clinical samples collected from 25 districts, DST was conducted for a total of 3,158 samples. Out of the total DSTs, the OFX profile was available for 2,983, MOX profile for 2,290, and LEV profile for 544 samples. OFX and LEV resistance was found to be evenly distributed and has remained the same for the past few years, whereas MOX resistance increased from 1% in 2017 to 4% in 2019. Among a total of 807 OFX-resistant isolates, 218 (27%) were observed to be monoresistant to OFX, whereas 589 (73%) isolates were resistant to OFX and at least one other anti-TB drug. Drug resistance to OFX was higher in multidrug-resistant TB (MDR-TB), that is, 428 (53%). It was concluded that resistance to MOX has been increasing, whereas OFX resistance is much higher in MDR cases. FQ resistance needs to be continuously monitored to avoid further side effects. This study provides useful information for better management of FQ resistance with reference to the global TB control program 2030.
Keywords: LEV; MOX; OFX; fluoroquinolones.