Genetic diversity and resistance molecular characteristics of clinical tested strains of Mycobacterium tuberculosis in Zhaotong area, Yunnan Province
QIAN Yuan
FAN Huaiyan
HE Zhijian
WANG Mei
Abstract：Objective To investigate the genetic diversity and drug resistance of clinical strains of Mycobacterium tuberculosis (MTB) in Zhaotong, Yunnan Province. Methods From September 2022 to August 2023, 298 clinical isolates of MTB from smear-positive pulmonary tuberculosis patients in The ZhaoTong Affiliated Hospital of Kunming Medical University were collected. MeltPro TB assay was used to identify all isolates by fluorescence PCR meltdown curve. Spoligotyping analysis was performed using the polychromatic melting curve analysis technique. Genotyping was performed by Mcspoligotping and Mycobacteria interspersing repetitive unit Variable Tandem repeats (MIRU-VNTR) 24-site typing. Drug-resistant gene mutations were detected using PCR and targeted sequencing. Results The Beijing strain accounted for 69.80％ (208/298) of all MTB strains. Other lineages include T, LAM, MANU2, CAS, NEW-1, and orphan types not found in the SITVITWEB database. They were 5.70％ (17/298), 3.36％ (10/298), 0.67％ (2/298), 0.34％ (1/298), 8.39％ (25/298) and 11.74％ (35/298), respectively. The resistance of the Beijing strain to levofloxacin was slightly higher than that of the non-Beijing strains (P=0.042), but there was no significant difference in isoniazid, rifampicin, ethambutol, streptomycin, pyrazinamide, kanamycin and other resistance profiles between the 2 genotypes (P >0.05). The results of MIRU-VNTR 24 locus typing showed that the 33 strains could be grouped into 13 clusters, and the clustering rate was 39.39％. According to the Hunter-Gaston discriminant index, the diversity of each allele varied significantly from 0 to 0.814, with 18 loci having medium-high discriminability against non-Beijing strains. However, only 10 loci had medium-high discriminability against the Beijing strain. Conclusion MTB strains in Zhaotong, Yunnan, China, show a high genetic diversity. The Beijing strain is the dominant lineage of MTB and drug-resistant TB strains.
Keywords：ZhaotongYunnan ProvinceMycobacterium tuberculosisgenetic diversitymycobcterial interspersed repetitive units-variable number of tandem repeat typing 24MTB Spoligotyping
Publication Date：2024-02-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 35-40 )