Abstract:

Objective To investigate the pyrazinamide (PZA) resistance of 125 multidrug-resistant (MDR) Mycobacterium tuberculosis isolates and the characteristics of mutation in pncA gene, to provide references for the rapid diagnosis of PZA resistance. Methods A total of 125 MDR strains were simple randomly selected from 9 drug-resistant surveillance sites in Fujian, 2010—2019. The PZA susceptibility was tested using the MGIT 960 system, and the pncA target gene was amplified by PCR to analyze the resistance of MDR strains to PZA and the mutation of pncA gene. Results A total of 50 MDR strains were resistant to PZA, and the PZA resistance rate was 40.0% (50/125). There was no statistical difference of the PZA resistance rate between the male (39.0% (37/95)) and the female (43.3% (13/30);χ²=0.183, P=0.669). The PZA resistant rates in the age-group of 15-25, 26-45, 46-60 and 61-80 years were 58.3% (7/12), 32.7% (16/49), 39.5% (17/43)and 47.6% (10/21), respectively, the difference was no statistically significant (χ²=3.294, P=0.348). There was no statistical difference of the PZA resistance rates between the new cases (41.5% (21/65)) and the retreatment cases (38.3% (23/60);χ²=0.134, P=0.715). The mutation of pncA gene was found in 30 PZA resistant MDR strains, and the types of mutations was 22. The mutation rate of pncA gene in PZA resistant MDR strain was 60.0% (30/50), which was significantly higher than that of the PZA sensitive strains (5.3% (4/75), χ²=45.276, P=0.000). Conclusion The PZA resistance rate of MDR Mycobacterium tuberculosis is high in Fujian, and the mutation of pncA gene is also high, attention should be paid to the drug resistance of PZA in clinic.

Key words: Mycobacterium tuberculosis, Pyrazinamide, Drug resistance, Gene mutation