1.Analysis on Resistance Status of 279 Strains of Mycobacterium tuberculosis
Lianyong CHEN ; Li MA ; Haohao RU ; Jinyu WANG ; Lin XU
Journal of Kunming Medical University 2014;(1):47-50
Objective The purpose of the study was to understand the resistance status of to anti-tuberculosis drug in Yunnan province, and to provide evidence for tuberculosis (TB) control. Methods The proportional method was used in drug sensitivity test according to the guidelines recommending by WHO. Results Of 301 mycobacterial isolates, 279 (92.7%) strains were complex (MTBC) . The total drug resistance rate was 31.5% (88/279),the initial drug resistance rate of was 27.3%, and the acquired drug resistance rate was 44.3%. The drug resistance rates to INH,RFP,EMB and SM were 19.7%, 10.8%, 12.9%and 19.0%, respectively. The multi-drug resistance (MDR) rate was 9.3%. Conclusion The drug resistant rate of is still high in Yunnan province,and TB control is still a long way to go. Early detection and regular treatment should be done for MDR patients. Drug resistance monitoring as an important part of TB control programs should be regular observation and research.
2.Evaluation of MTBDRplus 2.0 in the diagnosis of drug resistance of Mycobacterium tuberculosis
RU Haohao ; YANG Xing ; CHEN Lianyong ; CHEN Tao ; YAN Shuangqun ; XU Lin
China Tropical Medicine 2024;24(3):271-
Objective To evaluate the sensitivity and specificity of the GenoType MTBDRplus V2.0 (Mycobacterium tuberculosis and resistance gene detection assay kit using PCR-linear probe hybridization with enzyme chromogenic method, referred to as MTBDRplus 2.0) kit for detection of rifampin and isoniazid resistance, providing the basis for improving the detection of drug-resistant Mycobacterium tuberculosis. Methods From January to December 2022, positive strains of Mycobacterium tuberculosis isolated and cultured from designated tuberculosis treatment hospitals in 32 counties (cities, districts) of Yunnan Province were collected. Resistance in 880 strains of Mycobacterium tuberculosis was detected by MTBDRplus 2.0, and the minimum inhibitory concentration (MIC) method was used for the drug sensitivity test. Results Using the MIC method as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value of MTBDRplus 2.0 in detecting isoniazid resistance were 67.69%, 98.40%, 77.19%, and 97.45%, respectively. The consistency of the linear probe method and MIC method in detecting isoniazid resistance was moderate, with a Kappa value of 0.701 (P<0.001); the sensitivity, specificity, positive predictive value, and negative predictive values of MTBDRplus 2.0 in detecting rifampicin resistance were 87.80%, 99.40%, 87.80%, and 99.40%, respectively. The consistency of rifampicin resistance detection between MTBDRplus 2.0 and MIC method was relatively good, with a Kappa value of 0.872 (P<0.001). Among the 13 strains showing resistance to isoniazid with MTBDRplus 2.0, but sensitivity according to the MIC method, 11 strains (84.62%) had mutations in the inhA gene (C15T). Out of the 5 strains showing resistance to rifampicin with MTBDRplus 2.0, but sensitivity according to the MIC method, 4 strains (80.00%) had other mutations in the rpoB gene. Conclusions MTBDRplus 2.0 shows high sensitivity and specificity in detecting rifampicin resistance, but slightly low sensitivity in detecting isoniazid resistance. The low sensitivity in detecting isoniazid resistance may be due to insufficient target coverage of the detection kit. inhA gene mutations are poorly correlated with isoniazid resistance, and other mutations in the rpoB gene are poorly correlated with rifampicin resistance.
3. A study on genotype of 271 mycobacterium tuberculosis isolates in 6 prefectures in Yunnan Province
Lianyong CHEN ; Xing YANG ; Haohao RU ; Huijuan YANG ; Shuangqun YAN ; Li MA ; Jin'ou CHEN ; Rui YANG ; Lin XU
Chinese Journal of Preventive Medicine 2018;52(1):62-67
Objective:
To understand the characteristics of genotypes of Mycobacterium tuberculosis isolates in Yunnan province, and provide the molecular epidemiological evidence for prevention and control of tuberculosis in Yunnan Province.
Methods:
Mycobacterium Tuberculosis isolates were collected from 6 prefectures of Yunnan province in 2014 and their Genetypes of Mycobacterium tuberculosis isolates were obtained using spoligotyping and multiple locus variable numbers of tandem repeats analysis (MLVA). The results of spoligotyping were entered into the SITVITWEB database to obtain the Spoligotyping International Type (SIT) patterns and the sublineages of MTB isolates. The genoyping patterns were clustered with BioNumerics (version 5.0).
Results:
A total of 271 MTB isolates represented patients were collected from six prefectures in Yunnan province. Out of these patients, 196 (72.3%) were male. The mean age of the patients was (41.9±15.1) years. The most MTB isolates were from Puer, totally 94 iusolates(34.69%). Spoligotyping analysis revealed that 151 (55.72%) MTB isolates belonged to the Beijing genotype, while the other 120 (44.28%) were from non-Beijing genotype; 40 genotypes were consisted of 24 unique genotypes and 16 clusters. The 271 isolates were differentiated into 30 clusters (2 to 17 isolates per cluster) and 177 unique genotypes, showing a clustering rate of 23.62%. Beijing genotype strains showed higher clustering rate than non-Beijing genotype strains (29.14% vs 16.67%). The HGI of 12-locus VNTR in total MTB strains, Beijing genotype strains and non-Beijing genotype was 0.993, 0.982 and 0.995 respectively.
Conclusion
The Beijing genotype was the predominant genotype in Yunnan Province, the characteristics of Mycobacterium tuberculosis showed high genetic diversity. The genotyping data reflect the potential recent ongoing transmission in some area, which highlights the urgent need for early diagnosis and treatment of the infectious TB cases, to cut off the transmission and avoid a large TB outbreak.