Abstract:

Objective To analyze the difference of pyrazinamide（PZA）resistance rates of Mycobacterium tuberculosis clinical isolates with different backgrounds of first ⁃line anti ⁃tuberculosis drug resistance in southern China，and explore the possible factors influencing PZA resistance in Mycobacterium tuberculosis，so as to provide a research basis for further revealing the PZA resistance mechanism of Mycobacterium tuberculosis. Methods The clinical isolates of Mycobacterium tuberculosis from tuberculosis patients in our hospital from november 2012 to december 2018 were taken as the research objects. According to their resistance groups to isoniazid，rifampicin， ethambutol and streptomycin（here in after referred to as H，R，E and S respectively），the differences of PZA resistance rates of Mycobacterium tuberculosis with different drug resistance combinations and rifampicin resistance characteristics were analyzed. Results （1）The PZA resistance rates of Mycobacterium tuberculosis resistant to 0， 1，2，3 and 4 kinds of anti⁃tuberculosis drugs mentioned above were 3.75%，8.60%，28.21%，57.59% and 75.74%， respectively. Chi ⁃ square test showed statistically significant differences between any two groups （P < 0.005）. （2）The resistance rates of rifampicin resistant and sensitive Mycobacterium tuberculosis to PZA were 56.03% and 12.51%，respectively，and the difference between the two groups was statistically significant（P < 0.05）（. 3）PZA resistance rates of drug sensitive（Q），and the S，H，E，R，SE，RS，HS，RE，HR，HE，HSE，RSE，HRS，HRE and HRSE resistant isolates are 3.75%，4.92%，11.36%，12.12%，17.78%，7.14%，18.00%，18.20%，37.50%， 40.98% ，48.57% ，50.00% ，50.00% ，54.71% ，70.18% and 75.74%respectively. Chi⁃square test showed that the differences of PZA resistance rates between 15 groups of drug⁃resistant bacteria and sensitive isolates group showed that the differences of PZA resistance rates between S，E，SE ⁃ resistant isolates and four drug sensitive isolates were 0.078，0.004 and 0.4160，respectively，with no statistical significance（P > 0.003），while differences in the other groups had statistical significance（P < 0.000）. Conclusions The resistance of rifampicin and the combina⁃ tion with other first ⁃line anti ⁃tuberculosis drugs resistance may be the important factors affecting the resistance of Mycobacterium tuberculosis to PZA.

Key words:

Mycobacterium tuberculosis, Pyrazinamide, drug resistance, Rifampicin, first line anti?tuberculosis drugs