Hu Yan, Yu Min, You Guoqing, Fan Jun, Zheng Huiwen
Tuberculosis Reference Laboratory, Chongqing Tuberculosis Control Institute, Chongqing, People's Republic of China.
Laboratory of Respiratory Diseases, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Key Laboratory of Major Diseases in Children, Ministry of Education, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, People's Republic of China.
Infect Drug Resist. 2024 May 24;17:2069-2076. doi: 10.2147/IDR.S459142. eCollection 2024.
We compared the MeltPro assay to whole-genome sequencing (WGS) to investigate the molecular characterization of second-line injectable drug (SLID) resistance in multidrug-resistant tuberculosis (MDR-TB) isolates in Chongqing, China.
A total of 122 MDR-TB patient isolates were collected between March 2019 and June 2020 from Chongqing Municipality, China. Conventional drug-susceptibility testing was performed using the proportion method, followed to generate minimum inhibitory concentrations (MICs) of SLIDs determined by microplate alamarblue assay. All strains were subjected to both MeltPro and WGS assays.
Among 122 MDR-TB isolates, 30 (24.6%), 22 (18.0%), and 14 (11.5%) were resistant to kanamycin (KM), amikacin (AM), and capreomycin (CM), respectively. Of the 31 SLID-resistant isolates, 24 (77.4%, 24/31) isolates harbored mutations in the gene, with the most prevalent mutations in A1401G (22/24, 91.7%). Mutation in A1401G was associated with high levels of resistance to KM (MIC, ≥40 μg/mL) and AM (MIC, ≥64 μg/mL), but disparities in CM-resistance levels. Using phenotypic drug-susceptibility testing as gold standard, we found that the overall sensitivity of MeltPro and WGS was 87.1% and 90.32% and specificity 100% and 97.8%, respectively. Seven isolates had discordant results between phenotypic and genotypic resistance of SLIDs.
MeltPro is a promising diagnostic tool for accurate identification of SLID-resistant MTB isolates with mutations in the and genes. There was a disparity between MeltPro with WGS results in the proportion of heterogeneous drug-resistant bacteria with mutation and limited probes. Resistance mechanisms other than genetic mutations will affect the consistency of MeltPro and WGS with phenotypic drug-susceptibility results.
我们将MeltPro检测法与全基因组测序（WGS）进行比较，以研究中国重庆耐多药结核病（MDR-TB）分离株中二线注射用药物（SLID）耐药性的分子特征。
2019年3月至2020年6月期间，从中国重庆市共收集了122株MDR-TB患者分离株。采用比例法进行常规药敏试验，随后通过微孔板alamarblue检测法确定SLID的最低抑菌浓度（MIC）。所有菌株均进行MeltPro检测和WGS检测。
在122株MDR-TB分离株中，分别有30株（24.6%）、22株（18.0%）和14株（11.5%）对卡那霉素（KM）、阿米卡星（AM）和卷曲霉素（CM）耐药。在31株对SLID耐药的分离株中，24株（77.4%，24/31）分离株的 基因存在突变，其中最常见的突变是 A1401G（22/24，91.7%）。 A1401G突变与对KM（MIC，≥40μg/mL）和AM（MIC，≥64μg/mL）的高水平耐药相关，但在CM耐药水平上存在差异。以表型药敏试验为金标准，我们发现MeltPro和WGS的总体敏感性分别为87.1%和90.32%，特异性分别为100%和97.8%。7株分离株在SLID的表型和基因型耐药性之间存在不一致结果。
MeltPro是一种有前景的诊断工具，可准确鉴定 和 基因发生突变的耐SLID的MTB分离株。MeltPro与WGS结果在 基因突变的异质性耐药菌比例和探针有限方面存在差异。除基因突变外的耐药机制将影响MeltPro和WGS与表型药敏结果的一致性。
