To observe the serum concentration of bedaquiline in multidrug-resistant and rifampicin-resistant pulmonary tuberculosis(PTB) patients, and to explore the correlation between efficacy, safety and serum concentration.

A total of 37 MDR/RR-PTB patients hospitalized in Chongqing Public Health Medical Center from September 2019 to August 2021 were selected and treated with bedaquiline, including 23 males and 14 females, aged 15-60 years. The serum concentration of bedaquiline was determined by ultra performance liquid chromatography-mass spectrometry. The serum concentration and the correlation between efficacy, safety and serum concentration of bedaquiline were evaluated. The optimal cut-off value of bedaquiline concentration was analyzed by receiver operating characteristic curve. SPSS 26.0 statistical software was used for data analysis, and P<0.05 was considered statistically significant.

The serum concentration of bedaquiline in 2 hours (C_{2 h}), 6 hours (C_{6 h}) and next time of taking medicine (C_{24 h}) were 0.01-6.52,0.88-7.60,0.11-4.14 mg/L, respectively. Among the 37 patients, sputum culture turned negative in 30, but one case was still tested positive for Mycobacterium tuberculosis, while the drug was stopped in 3 cases due to QTcF≥500 ms, and another 3 cases were lost to follow-up. The sputum culture negative conversion time was 2-12 (6.00±2.79) weeks, and the sputum culture negative conversion rate in 12 weeks was 94.60%. Correlation analysis showed that C_{24 h} of bedaquiline was positively correlated with the sputum culture negative conversion time, and C_{6 h} of bedaquiline was positively correlated with improvement of lesions and adverse reactions (all P<0.05). Although there was no statistically significant difference, the constituent ratio of lesions and cavities in lung and adverse reaction in high C_{24 h} group were more than that those in low C_{24 h} group, and the QTcF and the constituent ratio of QT interval prolonged were higher in the high C_{6 h} group.

The overall efficacy and safety of bedaquiline in the treatment of MDR/RR-PTB were satisfactory. The sputum culture negative conversion time might be shorter when C_{24 h} was more than 0.78 mg/L. Meanwhile, C_{6 h} above 2.85 mg/L was beneficial to improvement of lesions, but the rate of adverse reactions might be higher. There was a trend of correlation between serum concentration and short-term efficacy and safety.

Tuberculosis, multidrug-resistant; Rifampicin; Bedaquiline; Serum concentration; Treatment outcome