Pyrazinamide Resistance and pncA Mutation Profiles in Multidrug Resistant Mycobacterium Tuberculosis

Abstract

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 pncA of M. tuberculosis 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 M. tuberculosis isolates. Results An evaluation of 82 MDR M. tuberculosis 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 pncA 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 pncA mutations and PZA resistance was significant under 100 and 300 mg/L. The sensitivity of pncA 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.

Drug Exposure and Susceptibility of Pyrazinamide Correlate with Treatment Response in Pyrazinamide-Susceptible Patients with Multidrug-Resistant Tuberculosis

“…During the study period, M. tuberculosis isolates in 19.0% (71/374) of participants were resistant to pyrazinamide, which is lower than 40% in the previous study conducted in Chinese patients with MDR-TB [ 9 ]. This may be attributed to the fact that more than 80% of the registered patients during this study were newly diagnosed and no previous usage of pyrazinamide may lead to a relatively lower resistance to pyrazinamide [ 18 ]. On the other hand, this study shows that the majority of patients with MDR-TB and M. tuberculosis isolates resistant to pyrazinamide have high-level MICs.…”

“…Previous studies indicated that pyrazinamide susceptibility is associated with better treatment responses [ 6 , 8 , 14 ]. However, the proportion of pyrazinamide resistance ranges from 10% to 85% among patients with MDR-TB in different geographic populations [ 15 , 16 , 17 , 18 ], which indicates the necessity of considering how to better use pyrazinamide.…”

Exploring of pyrazinamidase recombinant activity from PZA-sensitive and resistant Mycobacterium tuberculosis expressed in Escherichia coli BL21 (DE3)

“…Pyrazinamide (PZA) is a TB drug with a high bacteriocidal effect, because it can kill semidormant of M. tuberculosis (Shi et al, 2022;Shrestha et al, 2022).The efficacy of PZA as a TB drug is highly dependent on the action of the pyrazinamidase (PZase) enzyme encoded by the pncA gene of M. tuberculosis. As many as 80% of clinical isolates of PZA-resistant M. tuberculosis were reported to have pncA mutations (Khawbung et al, 2021;Lamont et al, 2020).…”

“…As many as 80% of clinical isolates of PZA-resistant M. tuberculosis were reported to have pncA mutations (Khawbung et al, 2021;Lamont et al, 2020). The types of mutations in the pncA gene were reported to be very diverse, and showed specificity in each geographic area where these clinical isolates were found (Hadi et al, 2023;Shi et al, 2022;Shrestha et al, 2022;Lamont et al, 2020;Purkan et al, 2016). M. tuberculosis strains that are defective in pncA thereby eliminating its PZase activity are reported to be resistant to PZA.…”

“…Approximately 10-15% of the total pncA mutations in PZA-resistant M. tuberculosis strains are reported to be multiple mutations. The variety and position of mutations in these genes are unique to each geographic area where resistant strains are obtained (Shi et al, 2020;Kahbazi et al, 2018;Shi et al, 2022;Shrestha et al, 2022).…”