The Relation Between the Emergence of Fluoroquinolone Resistance and Fluoroquinolone Exposure in New Cases of Active Pulmonary Tuberculosis

OBJECTIVE: This study aimed to determine the ratio of fluoroquinolone (FQ) exposure before the diagnosis of patients with a new case of active pulmonary tuberculosis (TB) and to investigate the correlation of this treatment with the emergence of FQ-resistant strains.

MATERIAL AND METHODS: In this retrospective comparative case series study, a total of 132 patients, who had been diagnosed with adult, culture-positive, active pulmonary TB were reviewed. The FQ group had 30 patients who had had ≥1 time and ≥7 days of FQ exposure within 1 year before the diagnoses. The control group included an equal number of patients with TB with similar demographic characteristics (non-FQ group). Ofloxacin (OFX) and moxifloxacin (MFX) resistance were examined at 2 different concentrations (2 and 4 mg/L for OFX; 0.25 and 0.5 mg/L for MFX).

RESULTS: Of the 132 patients, 30 (22%) had 7 days or longer of FQ monotherapy within 1 year of initiation of anti-TB treatment. FQ resistance was detected in 2 (3.3%) patients. In the FQ group, MFX resistance at 0.25 mg/L concentration was observed in 1 patient, whereas another patient had OFX and MFX resistance at 4 mg/L and 0.5 mg/L concentrations, respectively. In the non-FQ group, no FQ resistance was detected in any of the patients. No statistically significant difference in terms of development of FQ resistance was found between the ratios of FQ and non-FQ groups (p=0.492). Although there was no statistically significant difference, 2 patients, in whom resistance was detected, had FQ exposure before their diagnosis.

CONCLUSION: The FQ exposure ratio before the diagnosis is high (22%) in this cohort that includes patients with new active pulmonary TB, and the presence of patients with FQ resistance (even if only a few) should be a noteworthy and cautionary result in terms of FQ exposure and resistance development.

Cite this article as: Aydın Kayalı R, Özkan SA, Biçmen C, Erer OF. The relation between the emergence of fluoroquinolone resistance and fluoroquinolone exposure in new cases of active pulmonary tuberculosis. Turk Thorac J 2021; 22(1): 45-9.