Objective: It is a challenge to obtain satisfactory treatment outcomes for patients with multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB); the study aims to correlate the Minimum Inhibitory Concentration (MIC) value of drugs with the outcome of patients with MDR/RR-TB to obtain an understanding for better regimens and optimal outcomes.
Methods: The patients diagnosed with MDR/RR-TB were retrospectively enrolled from January 1, 2018 to December 31, 2019, recorded clinical characteristics, MIC DST (Drug Susceptibility Test) results, and followed the treatment outcome. The data were analyzed on the correlations of MIC DST values with outcomes and clinical characteristics.
Results: A total of 276 patients with MDR/RR-TB were included, containing 98 cases (35.5%) with newly treated patients and 178 cases (64.5%) with re-treated patients. A total of 220 cases recorded treatment success (79.7%) and 49 cases recorded treatment failure or died. MIC values of isoniazid (H), moxifloxacin (Mfx), and ethionamide (Eto) in newly treated patients were lower than those in retreated patients, and resistance levels of Mfx and H were closely associated with the treatment outcome (P < 0.05) while those of other drugs had no close association with treatment outcome.
Conclusions: MIC values of some anti-TB drugs, such as fluoroquinolones (FQs) and H, can reflect the treatment outcome for patients with MDR/RR-TB, which can contribute to making regimens for better treatment outcomes.
Keywords: MIC value, resistance, MDR/RR-TB, newly treated, retreated, treatment outcome