Analysis of Drug Resistance and Molecular Epidemiology among Pulmonary Tuberculosis Patients in Meigu County,Liangshan Yi Autonomous Prefecture

REN Yixuan; LI Jie; HE Xin; BI Bucise; FANG Yong; ZHANG Jie

doi:10.3639/j.issn.2095-3097.2026.02.011

Abstract：Objective To obtain the multidrug resistance status and the distribution of mutation loci in rifampicin/isoniazid resistance-related genes in clinically isolated strains from tuberculosis patients in Meigu County,Liangshan Yi Autonomous Prefecture,and to understand the transmission relationship of drug-resistant strains among tuberculosis patients in 2024.Methods A total of 378 clinical isolates from culture-positive tuberculosis patients were collected from the Meigu County Center for Disease Control and Prevention in Liangshan Yi Autonomous Prefecture between 2022 and 2024.Drug resistance patterns and resistance gene mutation sites were obtained using the DNA microarray chip method.Whole genome sequencing was performed on clinically isolated strains from patients with drug-resistant tuberculosis identified by the DNA microarray chip method to obtain the clustering rate of drug-resistant clinical isolates and to analyze the transmission patterns of Mycobacterium tuberculosis.Results From 2022 to 2024,the resistance rates of rifampicin,isoniazid,and multidrug resistance all showed an initial increase followed by a decrease.However,only the fluctuation in the isoniazid resistance rate was significant,with a statistically significant difference(χ2=6.277,P=0.043).There were no statistically significant differences in the resistance rates of rifampicin-resistant tuberculosis,isoniazid-resistant tuberculosis(HR-TB),and multidrug-resistant tuberculosis between different genders(P>0.05).The HR-TB resistance rate in patients aged 18-60 years was significantly higher than that in patients aged 0-18 years and>60 years(P<0.05).The chip method detected 31 rpoB mutant drug-resistant strains,including 25 strains with single-site mutations and 6 strains with double-site mutations.Among the 19 isoniazid-resistant strains detected by the chip method,15 had a single mutation at the katG 315 locus and 4 had mutations at the inhA locus.Whole genome sequencing was performed on 8 clinically isolated strains identified as drug-resistant by the chip method in 2024.Two strains with no detected genomic mutations were classified as sensitive strains,and 6 were drug-resistant strains(one of which was inconsistent).The consistency rate between the two methods was 62.50%.The main transmission lineages were lineage 2(East Asian genotype,accounting for 37.50%)and lineage 4(Euro-American genotype,accounting for 62.50%).Conclusion The drug resistance rate among tuberculosis patients in Meigu County shows unstable fluctuations,suggesting the persistence of non-standardized treatment.It is necessary to strengthen the monitoring of treatment compliance,with particular attention to the implementation of isoniazid treatment regimens.Young and middle-aged individuals aged 18-60 years are a high-risk population for drug resistance,and targeted screening and intervention should be implemented.