Analysis of pyrazinamide resistance of multidrug-resistant Mycobacterium tuberculosis in Henan Province and its relationship with the mutation of drug resistance-related gene pncA
10.3760/cma.j.cn311365-20200413-00494
- VernacularTitle:河南省耐多药结核分枝杆菌对吡嗪酰胺耐药性分析及其与耐药相关基因 pncA突变的关系
- Author:
Guolong ZHANG
1
Author Information
1. 河南省疾病预防控制中心结核病防治所，郑州 450016
- Keywords:
Mycobacterium tuberculosis;
Pyrazinamide;
Tuberculosis, multidrug-resistant;
pncA gene
- From:
Chinese Journal of Infectious Diseases
2021;39(7):424-429
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the performance of the sequencing method of pncA mutations in detecting pyrazinamide (PZA)resistance in multidrug-resistant tuberculosis (MDR-TB) patients in Henan Province. Methods:Sputum samples of 152 MDR-TB patients were collected from 10 drug-resistance surveillance areas in Henan Province from January to December 2018. Questionnaire survey was conducted to collect the information, such as age, gender, treatment history and sputum culture results. The questionnaire and strain samples were sent to Henan Provincial Center for Disease Control and Prevention for further study. PZA susceptibility test was performed using the liquid medium for Mycobacterium tuberculosis. The mutations of pncA were detected by polymerase chain reaction (PCR)and sequencing, then compared with the sequence of standard strain H37Rv. The association between PZA resistant phenotype and treatment outcomes was also investigated. Chi square test and independent sample t test were used for statistical analysis. Results:Among 152 MDR-TB isolates, 105 showed phenotypically PZA resistant. The proportion of PZA resistance in the isolates with isoniazid, rifampicin, ethambutol and streptomycin resistance, pre-extensively drug-resistant and extensively drug-resistant (XDR) were 80.39%(82/102), 81.13%(43/53) and 92.59%(25/27), respectively. One hundred and two isolates had mutations in the pncA gene. Based on the results of the phenotypic drug sensitivity test, the sensitivity of pncA gene mutation detection for PZA resistance was 89.52%(95% confidence interval ( CI) 81.64%-94.39%), and the specificity was 89.36%(95% CI 76.10%-96.01%). These MDR-TB isolates harbored 100 different mutation patterns in the pncA gene, including 80 point mutations and 20 indel mutations, and 13 isolates harbored multiple mutations. Seven strains had mutation in the promoter of pncA, including -7G insertion, -11T to C and -12A to G. The relative expression levels of pncA mRNA in the three groups were 0.21±0.05, 0.31±0.08 and 0.33±0.03, respectively, which were all lower than that of H37Rv(1.00). The differences were statistically significant ( t=4.57, 2.43 and 3.65, respectively, all P<0.05). The difference of the sputum negative conversion rates between patients with PZA-resistant isolates and those with PZA susceptible isolates was statistically significant at different time periods after treatment ( χ2=10.01, P=0.02). The negative conversion rate of PZA-resistant patients at the end of six months of treatment was 1.08%(1/93), and that of PZA-sensitive patients was 7.14%(3/42). Conclusions:The PZA resistance in MDR-TB isolates is associated with pncA mutations, which are scatered and diversified. The sputum negative conversion time of PZA-resistant patients is prolonged.
