The influence of pyrazinamide resistant associated gene mutations on multidrug-resistant mycobacterium tuberculosis in China

Abstract

Abstract Background Pyrazinamide (PZA) is essential for the treatment of drug-susceptible and drug-resistant tuberculosis (TB), especially multidrug-resistant (MDR) TB, but the condition of PZA resistance (PZA-R) across China is unknown. Our aim is to clarify the genetic mutations of PZA-R and the relationship between PZA-R and MDR-TB in China, from 2007 to 2019. Methods A total of 3202 TB strains with gene sequences results in China were included, among which 1447 strains were sequenced and 1775 were download from the European Nucleic Acid Sequence Database. Drug resistance was investigated by detecting resistance-conferring mutations. A phylogenetic tree was constructed to illustrate the genetic structure of the TB strains. Fisher's exact or Pearson's chi-square tests, as well as logistic regression analysis were used for correlation analysis. Those were calculated by SPSS software. Results All the 3202 strains were divided into four lineages (L1, L2, L3, L4), most belonged to L2 (2745, 85.7%), followed by L4 (443, 13.8%), the rest L1 plus L3 (14, 0.4%). About 45.6% (n = 1459) strains referred to isoniazid resistance (INH-R), 43.4% (n = 1389) rifampicin resistance (RIF-R), and 40.5% (n = 1296) MDR. There were 591 isolates resistant to PZA, among which 96.1% (n = 568) were also MDR. The rate of PZA-R was 43.8% (568/1296) among MDR isolates. The trends of PZA-R fluctuated in accordance with the trends of MDR, INH-R, RIF-R during 2007–2019. Up to 254 kinds of mutations associated with PZA-R were found, with 16.5% (n = 42) isolates harboring ≥ 2 PZA-R associated mutations. Codons 11 (encoding pncA_c.011A > G, n = 30, 11.8%), 76 (encoding pncA_p.Thr76Pro, n = 13, 5.1%), and 139 (encoding pncA_p.Val139Leu, n = 13, 5.1%) were the top three PZA-R associated mutation sites. All PZA-R mutation sites accounting at least 1% were included to analyse the influence of PZA-R on other drug resistance (MDR, INH-R, RIF-R). Finally, three PZA-R related mutations (pncA_p.Val139Ala, pncA_p.Thr47Ala, pncA_p.Leu85Pro) were associated with MDR, four were associate with (pncA_p.Thr76Pro, pncA_p.Val139Ala, pncA_p.Thr47Ala, pncA_p.Leu85Pro) INH-R and none was associated with RIF-R. Conclusion PZA-R especially gene mutation referred to pncA region may promote MDR, this phenomenon mainly associated with the function of PZA-R on INH-R. It is important to consider PZA-R particularly the three associated mutations (pncA region associated mutations) into consideration in treating MDR-TB and explore its mechanism.