Background: Empiric use of fluoroquinolone (FQ) antibiotics could delay tuberculosis (TB) treatment and lead to FQ-resistant TB.
Methods: We examined the impact of FQ use on TB outcomes, including smear status, treatment delay and FQ resistance, through a retrospective cohort study of 440 FQ-exposed and 511 non-exposed patients in a gold mining community in South Africa. We considered both recent (≤ 100 days before sputum collection) and distant exposure (≤ 1 year). We examined 201 and 180 isolates from FQ-exposed and non-exposed individuals for the presence of gyrA mutations.
Results: Patients recently exposed to ≥ 5 days of FQ were less likely to be smear-positive (OR 0.27, 95%CI 0.11-0.63), with an increased time to treatment (time ratio 2.02, 95%CI 1.19-3.44). The strength of association decreased when we considered distant exposure. Adjusting for smear status nullified the effect of FQ exposure on treatment delay. We detected a gyrA mutation in one isolate (0.5%) taken from an individual exposed to FQ for 8 days.
Conclusion: FQ exposure is associated with treatment delay, mediated by negative smear status. Short exposures to FQ do not routinely lead to resistance encoded by gyrA mutations. We recommend prudent use of FQ in settings with a high burden of human immunodeficiency virus and TB.