Dawei Shi: National Institutes for Food and Drug Control, Institute of Pathogen Biology at the Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China.
Qiulong Zhou: Engineering Research Centre of Molecular Diagnostics of the Ministry of Education, State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen, People's Republic of China. ORCID
Sihong Xu: National Institutes for Food and Drug Control, Institute of Pathogen Biology at the Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China.
Yumei Zhu: Shenzhen Center for Chronic Disease Control, Shenzhen, People's Republic of China.
Hui Li: Tuberculosis Reference Laboratory, Henan Provincial Centers for Disease Control and Prevention, Zhengzhou, People's Republic of China. ORCID
Ye Xu: Engineering Research Centre of Molecular Diagnostics of the Ministry of Education, State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen, People's Republic of China. ORCID
Purpose: Pyrazinamide (PZA) is a critical component of standardized chemotherapy for tuberculosis (TB) and is recommended for the treatment of multidrug-resistant (MDR) TB. We aimed to characterize mutations in of and evaluate their diagnostic accuracy for PZA susceptibility in China. We also combined genotypic methods with phenotypic susceptibility testing and pyrazinamidase (PZAse) activity to confirm PZA-resistant isolates. Results: An evaluation of 82 MDR strains revealed that 28.0% (23/82) were phenotypically resistant to 100 mg/L PZA and 15.9% (13/82) showed resistance to 300 mg/L PZA. Mutations in were detected at 33 unique sites, and the majority were point mutations. No evident mutation hotspots or mutations affecting multiple amino acids were found, but the association between mutations and PZA resistance was significant under 100 and 300 mg/L. The sensitivity of mutation detection for predicting PZA susceptibility was 82.6% (19/23), and the specificity was 61.0% (36/59), based on 100 mg/L PZA, whereas the sensitivity was 84.6% (11/13) and the specificity was 55.1% (38/69), based on 300 mg/L PZA. All mutations identified in the highly PZA-resistant (300 mg/L) strains had an 80% loss relative to PZAse activity. No evident PZAse activity loss was observed in one synonymous mutation strain and the loss exceed 60% in all other strains. Conclusion: The association between pncA mutation and PZA resistance was significant. Relatively, the molecular method have shown better reliability than the phenotypic method for the detection of PZA resistance. This provides a theoretical basis for the clinical diagnosis of drug-resistant TB.
