The Retrospective Diagnostic Potential of Gene Xpert MTB/RIF for the Analysis of Formalin-Fixed Paraffin-Embedded Tissue from Extrapulmonary Tuberculosis Patients

Tuberculosis(TB)is a chronic disease caused by infection with Mycobacterium tuberculosis.Laboratory confirmation of this infection is challenging due to the paucibacillary nature of extrapulmonary tuberculosis(EPTB).

Surgical Management of Mitral Valve Infective Endocarditis with Accidental Finding of Open Pulmonary Tuberculosis

Objective: This case report aimed to highlight intersections of TB and Cardiovasular diseases which carry high morbidity and mortality rates. Methods: We are reporting the surgical management of forty seven years female who had back ground history of IDDM (Insulin dependent diabetic Mellitus), ESRD (End stage renal disease) on HD (haemodialysis) also she had left subclavian artery stenosis, and paroxysmal atrial fibrillation. She was diagnosed with mitral valve infective endocarditis and found accidently to have an open pulmonary tuberculosis (TB) on the day before surgery. Results: She was started on first line anti-TB treatment. She was isolated in her private room and airborne precautions measures applied. The patient underwent a tissue Mitral Valve replacement and tricuspid valve repair annuloplasty. Special precautions were applied in Theatre and on cardiopulmonary bypass Machine guided by KAMC-J disinfection protocol. The patient made good recovery postoperatively. She was discharged well on day 7 post operatively. Conclusion: Intersections of TB and cardiovasular diseases carry high morbidity and mortality rates. Early diagnosis and early anti tuberculosis treatment can surely improve the patient prognosis. Our decontamination and disinfective procedures are recommended. Cases like this should be monitored long term for the development of further cardiovascular complication.

Missed Opportunities for Diagnosing Bacilliferous Pulmonary Tuberculosis by Optical Microscopy versus GeneXpert MTB/RIF in Endemic Areas

Objective: To assess the missed opportunities from the diagnosis of bacilliferous pulmonary tuberculosis by optical microscopy compared to GeneXpert MTB/RIF between 2015 and 2019. Methods: This is a retrospective analysis of the diagnostic results of bacilliferous pulmonary tuberculosis in patients suspected of pulmonary tuberculosis at their first episode during the period. GeneXpert MTB/RIF (GeneXpert) and optical microscopy (OM) after Ziehl-Neelsen stained smear were performed on each patient’s sputum or gastric tubing fluid sample. Results: Among 341 patients suspected of pulmonary tuberculosis, 229 patients were declared bacilliferous tuberculosis by the two tests (67%), 220 patients by GeneXpert and 95 patients by OM, i.e. 64.5% versus 28% (p i.e. 58.5% of the positive cases detected by the two tests (134/229 patients) and 39.3% of the patients suspected of tuberculosis (134/341 patients). On the other hand, among 95 patients declared positive by OM, the GeneXpert ignored 9 (9.5%), i.e. 4% of all the positive cases detected by the two diagnostic tests (9/229 patients) and 3% of the patients suspected of tuberculosis (9/341 patients). The differences observed between the results of the two tests were statistically significant at the 5% threshold (p Conclusion: This study reveals missed diagnostic opportunities for bacilliferous pulmonary mycobacteriosis, statistically significant with optical microscopy than GeneXpert. The GeneXpert/optical microscopy couple could be a good contribution to the strategies for the elimination of pulmonary tuberculosis in sub-Saharan Africa.

Comparison of Xpert MTB/RIF, Real Amp, and CPA Tests in Detecting Mycobacterium tuberculosis

Today, tuberculosis (TB) remains a global public health threat associated with significantly high rates of morbidity and mortality. The World Health Organization's (WHO) Global Tuberculosis Report 2018[1] has reported that in 2017, 10.0 million people across the world had developed TB diseases that resulted in an estimated 1.6 million deaths, and 889, 000 people developed TB in China that led to 39, 000 TB-related deaths. Therefore, rapid and accurate detection of Mycobacterium tuberculosis (MTB) is important for initiating early treatment and reducing mortality. Traditional diagnostic methods for pulmonary TB incorporate chest radiography and sputum smear microscopy;however, several cases of tuberculosis go undiagnosed because of the low sensitivity of smear microscopy[2].

Evaluation of Xpert MTB/RIF for the Diagnosis of Extrapulmonary Tuberculosis in China

We evaluate the performance of Xpert MTB/RIF for the diagnosis of extrapulmonary tuberculosis （EPTB） in China. The performance of Xpert was evaluated compared to the composite reference standard （CRS）, drug susceptibility testing （DST）, and imaging examination. The overall sensitivity and specificity of Xpert were 64.1% （195/304） and 100% （24/24）, respectively, using CRS as the gold standard. The sensitivity was significantly higher than that of culture for pus （P〈0.05）. The proportion of EPTB-positive cases diagnosed by imaging was two times more than that diagnosed using Xpert; however, 6 out of 19 cases may have been overdiagnosed by imaging.

结核分枝杆菌耐热抗原(MTB-HAg)对γδ T细胞影响的研究进展

结核分枝杆菌耐热抗原(MTB-HAg)是从结核分枝杆菌(MTB)减毒菌株H37Ra经121℃,20 min,高温高压处理后从菌体释放到上清液中一种多肽类抗原。γδ T细胞是一类广泛分布于非淋巴组织的非常规T细胞,可分泌肿瘤坏死因子α(TNF-α)、γ干扰素(IFN-γ)等细胞因子,在抗MTB感染的免疫应答中发挥重要作用。MTB-HAg可在体外有效刺激γδ T细胞增殖活化,使其更加高效地参与抗结核感染的过程,故MTB-HAg可作为设计新型结核疫苗或药物的潜在靶点。但由于MTB-HAg组成复杂,具体是何种成分刺激γδ T细胞发挥抗MTB感染功能还不清楚。

Diagnostic Evaluation of GeneXpert MTB/RIF Assay for the Detection of Rifampicin Resistant Mycobacterium tuberculosis among Pulmonary Tuberculosis Patients in Bangladesh

Background: The emergence of multidrug resistant tuberculosis (MDR-TB) and extensively drug- resistant tuberculosis (XDR-TB) has highlighted the need for early accurate detection and drug susceptibility. Objective: The purpose of the present study was to evaluate the accuracy of GeneX-pert MTB/RIF assay for the detection of Mycobacterium tuberculosis and rifampicin resistance. Methodology: This cross sectional study was done in the Department of Microbiology at Sir Salimullah Medical College, Dhaka and National Institute of Chest Disease & Hospital (NIDCH), Dhaka during the period of January 2014 to December 2014 for a period of 1 (one) year. Sputum samples from suspected MDR-TB patients were collected by purposive sampling technique from OPD of Sir Salimullah Medical College (SSMC) and NIDCH. Microscopy, liquid culture in liquid MGIT 960 media and GeneXpert MTB/RIF were done for MTB diagnosis and detection of rifampicin resistance. MGIT 960 media were also used for determination of drug resistance. Result: Liquid culture yielded higher growth (68%) from 100 samples while GeneXpert MTB assay showed similar result (67% positive and 33% negative). Drug susceptibility test in MGIT 960 media showed that out of 68 positive cases Rifampicin resistant cases were 15 (22.05%) whereas GeneXpert MTB assay detected 14 (20.89%) were Rifampicin resistant out of 67 MTB positive samples. When compared to liquid culture the calculated sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and accuracy of GeneXpert MTB were 98.52%, 100%, 96.96%, 100% and 99%. Conclusion: GeneXpert MTB/RIF assay is high detection rate of pulmonary tuberculosis and multidrug resistant tuberculosis.

Evaluation of Xpert MTB/RIF Ultra for Diagnosis of Extrapulmonary Tuberculosis: A Retrospective Analysis in a Low-Tuberculosis Prevalence Setting

Background: Extrapulmonary tuberculosis (EPTB) remains difficult to diagnose because the clinical specimens to be examined are often paucibacillary and obtained with difficulty from inaccessible sites. An updated Xpert® MTB/RIF Ultra (Ultra) test has been designed and licensed to improve sensitivity in the detection of Mycobacterium tuberculosis complex. The aim of the present study is to evaluate the performance of Ultra assay for the clinical diagnosis of EPTB in a low tuberculosis prevalence country. Methods: A retrospective analysis was performed at “A. O dei Colli” of Naples on consecutive extrapulmonary specimens for EPTB across a three-year period. All different types of extrapulmonary specimens were tested for EPTB by smear microscopy, culture and Ultra assay in accordance with relevant guidelines. Results: A total of 606 EPTB samples, 561 culture negative EPTB and 45 culture positive EPTB were included. Using culture as reference standard, the overall sensitivities and specificities of Ultra assay were 95.6% (95% CI 84.8 - 99.5) and 97.5% (95% CI 95.8 - 98.6) respectively. Sensitivity and specificity of Ultra for individual category of specimens were also performed. Conclusion: In a low-tuberculosis prevalence setting, Ultra assay confirms to have a good performance in the diagnosis of EPTB for all different extrapulmonary samples.

Xpert MTB/RIF联合宏基因组高通量测序对菌阴肺结核的诊断价值分析

目的探讨Xpert MTB/RIF联合宏基因组高通量测序对菌阴肺结核的诊断价值。方法回顾性分析2019年12月至2022年5月诊断为菌阴肺结核的70例患者,分别进行XpertMTB/RIF检测、宏基因组高通量测序及二者联合检测。采用固体培养法和比例法对生化病原菌进行诊断并分析诊断效能。采用预测值绘制受试者操作特征曲线。结果Xpert MTB/RIF诊断阳性率75.57%,阴性率21.43%;宏基因组高通量测序诊断阳性率78.57%,阴性率21.43%;联合诊断阳性率88.57%,阴性率11.43%。Xpert MTB/RIF检测敏感度为77.55%、特异性为59.86%,曲线下面积(area under the curve,AUC)为0.827;宏基因组高通量测序检测敏感度为77.47%、特异性为61.02%,AUC为0.808;联合检测敏感度为89.75%、特异性为89.57%,AUC为0.925。结果显示Xpert MTB/RIF联合宏基因组高通量测序在菌阴肺结核中诊断的敏感度、特异性均高于单一检测(P<0.05)。结论XpertMTB/RIF联合宏基因组高通量测序在菌阴肺结核诊断中具有较好的应用价值,值得临床推广使用。

支气管肺泡灌洗液Xpert MTB/RIF检测在肺结核早期诊断中的应用价值

目的分析支气管肺泡灌洗液Xpert MTB/RIF检测在肺结核早期诊断中的应用价值。方法选取我院2022年3月至2023年3月收治的96例疑似肺结核患者为研究对象,所有研究对象入组后均采集痰液、支气管肺泡灌洗液、浆膜腔积液标本,再分别进行Xpert MTB/RIF检测。以X线胸片、免疫检查(结核菌素皮肤试验或γ干扰素释放试验)等为金标准,比较三种标本Xpert MTB/RIF检测对肺结核的诊断效能。结果96例疑似肺结核患者中,经金标准检出肺结核89例,非肺结核7例。痰液与浆膜腔积液标本Xpert MTB/RIF检测对肺结核的诊断准确度、灵敏度、特异度、阳性预测值、阴性预测值均无显著差异(P>0.05);支气管肺泡灌洗液标本的Xpert MTB/RIF检测对肺结核的诊断准确度、灵敏度、特异度、阳性预测值、阴性预测值均显著高于痰液与浆膜腔积液标本,差异具有统计学意义(P<0.05)。结论在肺结核早期诊断中,开展支气管肺泡灌洗液Xpert MTB/RIF检测可取得较高诊断效能。

Xpert MTB/RIF Ultra在儿童结核诊断中的应用价值

目的:探讨Xpert MTB/RIF Ultra在儿童结核诊断中的应用价值。方法:选取2010年1月—2022年12月山东省公共卫生临床中心收治的150例患儿作为研究对象。根据临床综合诊断确诊结果将结核病感染患儿纳入试验组(n=100),将非结核病感染患儿纳入对照组(n=50)。计算不同标本类型的敏感度、特异度、阴性预测值、阳性预测值和准确度,评价Xpert MTB/RIF Ultra检出利福平(RIF)耐药性的效能。结果:Xpert MTB/RIF Ultra的检测所有标本总敏感度为77.00%,特异度为96.00%;合并肺内标本敏感度为92.85%,特异度为96.29%,其中肺内标本中肺泡灌洗液敏感度最高为100.00%;合并肺外标本敏感度为77.55%,特异度为95.65%,其中肺外标本中淋巴结敏感度最高为100.00%。结论:不同标本类型中Xpert MTB/RIF Ultra对儿童结核的检出率差异较大,在诊断肺内结核标本时,检测肺泡灌洗液标本价值最高,在诊断肺外结核标本时,检测淋巴结标本价值最高。

扩大GeneXpert MTB检测范围对病原学阳性及耐药肺结核患者发现率的影响

目的评价扩大GeneXpert MTB检测范围对病原学阳性结核病患者及利福平耐药结核病患者发现率的影响。方法从中国疾病预防控制信息系统子系统结核病信息管理系统收集2019—2022年徐州市、南通市、泰州市及镇江市4个设区市22家结核病定点医疗机构登记的22941例活动性肺结核患者的实验室检测、药敏检测等信息,分析2次扩大GeneXpert MTB检测范围,采用3种检测模式结果的差异。结果2019年经分枝杆菌涂片、培养及影像学诊断为活动性肺结核患者后,全部开展GeneXpert MTB(模式A),2020—2021年对非定点医院转诊的肺结核疑似患者采用GeneXpert MTB检测(模式B),2022年对定点医院结核门诊所有肺结核疑似患者采用GeneXpert MTB检测(模式C),以上3种模式中县级结核病定点医院发现的利福平耐药结核病患者,均转至市级结核病定点医院进一步诊断和治疗。2019—2022年4市登记的活动性肺结核患者病原学阳性率逐年提高,分别为56.07%、57.31%、59.03%、67.92%。;肺结核患者3种检测模式阳性检出率分别为56.07%、58.13%、67.92%,差异有统计学意义(χ^(2)=179.30,P<0.01);涂阴肺结核患者采用GeneXpert MTB检测,3种检测模式阳性检出率分别为25.91%、28.39%、47.70%,差异有统计学意义(χ^(2)=446.23,P<0.01);肺结核患者3种检测模式利福平耐药结核病发现率分别为2.16%、2.05%、2.16%,差异无统计学意义(χ^(2)=0.38,P=0.83)。结论通过推广GeneXpert MTB检测技术,肺结核患者病原学阳性检出率得到显著提升,对疾病防控有重要的意义,但扩大检测范围并提高利福平耐药结核病的发现率。

Xpert MTB/RIF技术在肺结核患者结核分枝杆菌鉴定及利福平耐药检测中的应用价值

目的分析Xpert MTB/RIF技术在结核分枝杆菌鉴定及利福平耐药性的检验效能及临床应用价值。方法收集感染科初诊疑似肺结核患者痰液样本,以临床确诊为金标准,评估涂片荧光染色法、Xpert MTB/RIF、液体培养法对结核分枝杆菌检测效能。以比例法药敏试验为金标准,评估Xpert MTB/RIF技术对结核分枝杆菌利福平耐药性检验效能。结果2019年5月至2021年5月初诊疑似肺结核患者593例,确诊肺结核141例,非结核分枝杆菌感染14例,其他肺部感染438例。593例疑似肺结核患者中,三种方法检测阳性率分别为:荧光染色法16.7%,Xpert MTB/RIF法23.4%,液体培养法23.6%。141例确诊肺结核患者中男性占比75.2%,其中涂片法敏感性为58.9%低于Xpert MTB/RIF 98.6%和液体培养法99.3%,涂片法特异性为96.46%、Xpert MTB/RIF和液体培养法特异性均为100%。Xpert MTB/RIF和液体培养法检测MTB一致性Kappa值均>0.99。以140株培养阳性结核杆菌比例法药敏试验结果为金标准,Xpert MTB/RIF法检测利福平耐药敏感性87.5%、特异性100%、准确性99.3%,与比例法药物敏感性试验结果一致性Kappa值0.93,结核杆菌利福平耐药率女性(8.6%)高于男性(4.8%)。结论临床确诊肺结核患者中Xpert MTB/RIF检测结核分枝杆菌一致性高、操作简单、敏感性与特异性好,对利福平耐药性检测与比例法比较结果符合率高。Xpert MTB/RIF可作为快速检测MTB及利福平耐药性的有效方法,并可为临床快速选择治疗方案提供参考。

Gene X-pert MTB/RIF检测对肺结核病的诊断价值研究

目的 研究分析肺结核病应用Gene X-pert MTB/RIF检测的诊断价值。方法 选取2022年3—10月在本院就诊的疑似肺结核病患者164例为研究对象,所有患者均给予结核分枝杆菌培养检查、痰涂片抗酸染色法诊断、Gene X-pert MTB/RIF检测,以结核分枝杆菌培养检查结果为金标准,比较痰涂片抗酸染色法诊断与Gene X-pert MTB/RIF检测的阳性率以及诊断准确性、灵敏度、特异度。结果 痰涂片抗酸染色法诊断阳性率为21.34%(35/164),Gene X-pert MTB/RIF检测阳性率为35.98%(59/164),Gene X-pert MTB/RIF检测明显高于痰涂片抗酸染色法诊断(P<0.05)。痰涂片抗酸染色法诊断的准确性为85.37%,灵敏度为59.65%,Gene X-pert MTB/RIF检测的准确性为95.12%,灵敏度为94.74%,Gene X-pert MTB/RIF检测明显高于痰涂片抗酸染色法诊断(P<0.05)。结论 在肺结核病诊断中,Gene X-pert MTB/RIF检测的阳性率更高,同时诊断准确率与灵敏度也更高,为肺结核病的诊断与治疗提供了可靠的指导依据。

γ-干扰素释放试验、Xpert MTB/RIF联合检测诊断艾滋病合并肺结核的价值分析

目的:分析γ-干扰素释放试验联合利福平耐药结核分枝杆菌实时荧光定量核酸扩增检测技术(Xpert MTB/RIF)诊断艾滋病合并肺结核的价值。方法:选取2018年1月-2021年12月苏州市第五人民医院收治的126例艾滋病疑似合并肺结核患者作为研究对象,均进行结核分枝杆菌培养、γ-干扰素释放试验与Xpert MTB/RIF检测,以结核分枝杆菌培养结果为“金标准”,比较不同诊断方式的效能。结果:结核分枝杆菌培养结果显示,126例艾滋病患者中,36例(28.57%)诊断为肺结核。联合检测诊断艾滋病合并肺结核的灵敏度、准确度、阴性预测值高于γ-干扰素释放试验、Xpert MTB/RIF单一检测,差异有统计学意义(P<0.05);γ-干扰素释放试验、Xpert MTB/RIF检测单项诊断艾滋病合并肺结核的灵敏度、准确度、阴性预测值以及三种方式诊断艾滋病合并肺结核的特异度、阳性预测值比较,差异无统计学意义(P>0.05)。结论:γ-干扰素释放试验联合Xpert MTB/RIF诊断艾滋病合并肺结核的效果较好,可作为辅助诊断艾滋病合并肺结核的方法。

A Mathematical Model of Tuberculosis with Drug Resistance Effects

Despite the enormous progress in prevention and treatment, tuberculosis disease remains a leading cause of death worldwide and one of the major sources of concern is the drug resistant strain, MDR-TB (multidrug resistant tuberculosis) and XDR-TB (extensively drug resistant tuberculosis). In this work, we extend the standard SEIRS epidemiology model of tuberculosis to include MDR-TB. For that, we considered compartments of susceptible, exposed, infected, resistant to a first line of treatment and recovered humans and we modeled the natural growth, the interactions between these populations and the effects of treatments. We calculate the basic reproduction number, , using the next generation method. The DFE and the EE are established and their stability analysis done to show that they are locally and globally asymptotically stable. Numerical analysis for the model with and without delay is done and demonstrated that in the case of patients with both active tuberculosis and MDR tuberculosis, both strains will still persist due to lack of permanent immunity to tuberculosis while the recovered can still lose their immunity to become susceptible again.

Fast and Accurate Identification of <i>M. tuberculosis</i>Complex Using an Immunochromatographic MPT64 Antigen Detection Test

Background: A new rapid Immunochromatographic test (ICT) kit (MPT64 TB Ag Kit) for detection of MPT64 Antigen in M. tuberculosis (MTB) isolates used for rapid identification of MTB isolates developed by SD (Standard Diagnostics) Bio line, South Korea was evaluated. The ICT is a rapid, reliable and cheaper method that can be used instead of conventional biochemical tests for confirming MTB in culture isolates in resource limited laboratories. The study also evaluated the ability of ICT to detect MPT64-Antigen before the micro MGIT could signal positive. Material/Methods: A total of 450 sputum samples of individual patients were used for the study. 152 isolates of Mycobacteria were recovered from solid and liquid media. These strains were tested for the detection of MPT64-antigen. H37Rv strain was served as the positive reference control and also used for early detection of Antigen experiment. Findings: The development of bands on both test and sample region when H37Rv strain was tested were seen (MPT64 antigen positive). When 138 MTB isolates were tested, it showed a similar banding pattern indicating 100% sensitivity. MPT64 band formation was not detected in any of the 14 isolates indicating 100% specificity. Both PPV & NPV were 100%. All the isolates negative for MPT64 Ag were confirmed as MOTT by conventional bio-chemical PNBA. The H37Rv strain showed a faint band from the 2nd day onwards from inoculation till 3rd day in the earlier Antigen detection experiment. Conclusion: Rapid identification of MTB culture isolate is a pressing need for diagnosis and proceeding to perform drug susceptibility testing. MPT64 TB Ag detection ICT kit is a rapid, reliable method, good substitute for molecular identification methods, and conventional biochemical test which is time-consuming and technically demanding. The early detection of Antigen can be used as an effective tool in diagnosis.

Xpert MTB/RIF Ultra快速诊断涂阴肺结核的临床价值

目的评估超敏结核分枝杆菌和利福平耐药基因检测(XpertUltra)方案检测痰液及支气管肺泡灌洗液(BALF)标本在涂阴肺结核患者中早期、快速诊断的价值。方法选择2020年5月-2021年12月在山东省公共卫生临床中心就诊的痰涂片阴性疑似肺结核患者93例,其中临床诊断为涂阴肺结核57例,非肺结核36例。收集所有患者的痰液及BALF标本,分别采用Xpert Ultra、GeneXpert MTB/RIF(Xpert)、BACTEC MGIT 960培养(MGIT 960培养)进行检测。以临床诊断为参考标准,评价3种检测方案及相互联合检测痰液及BALF标本时诊断涂阴肺结核的敏感度、特异度及符合率。结果以临床诊断结果为参考标准,Xpert Ultra检测痰液标本对涂阴肺结核诊断的敏感度明显高于Xpert[56.14%(32/57)vs.36.84%(21/57),P=0.03]和MGIT960培养[56.14%(32/57)vs.33.33%(19/57),P=0.014];Xpert Ultra检测BALF标本对涂阴肺结核诊断的敏感度明显高于Xpert[75.44%(43/57)vs.56.14%(32/57),P=0.030]和MGIT960培养[75.44%(43/57)vs.38.60%(22/57),P<0.01]。3种检测方案及相互联合检测痰液标本诊断涂阴肺结核,受试者工作特征(ROC)曲线下面积(AUC)依次为:三者联合(0.807)>Xpert Ultra+Xpert(0.798)>Xpert Ultra+MGIT 960培养(0.789)>Xpert Ultra(0.781)>Xpert(0.684)>MGIT 960培养(0.667);检测BALF标本,AUC依次为:三者联合(0.895)=Xpert Ultra+Xpert(0.895)>XpertUltra+MGIT960培养(0.877)=XpertUltra(0.877)>Xpert(0.781)>MGIT960培养(0.693)。3种检测方案均未在入组患者中检测到利福平耐药。结论Xpert Ultra对早期、快速诊断涂阴肺结核具有较高的临床应用价值;其检测BALF的敏感度高于痰液标本,建议优先选择BALF标本。

Stool as Appropriate Sample for the Diagnosis of <i>Mycobacterium</i><i>tuberculosis</i>by Gene Xpert Test

Background: Diagnosis of pediatric pulmonary tuberculosis (PTB) is a challenge. Symptoms are nonspecific. Young children are unable to expectorate sputum samples;the procedures for obtaining respiratory samples are invasive. Thus Mycobacterium tuberculosis cultures and smears often are not performed. Stool samples were used as an alternative to respiratory samples for the diagnosis of pediatric PTB using stool Xpert MTB/RIF and its sensitivity for detecting the DNA of MTB in stool was determined. Methods: The study was a laboratory-based cross-sectional prospective design. Stool specimen was collected from PTB suspected children (<15 years) attended in Gertrude’s Children’s Hospital Nairobi and Kiambu District Hospital from September 2013 to March 2014. Stool for Xpert was processed in two ways, direct and prior extraction of DNA using QIAGEN stool DNA extraction kit. Result: A total sample of 91 stool specimen was collected from patients. Of these 53 (58.2%) had sputum ZN smear microscopy. Six (11.3%) of them were confirmed smear positive for PTB. Stool Gene Xpert was positive in all the six smear positive children. Four (7.5%) smear negative patients tested positive by stool Gene Xpert test. This association is significant (P = 0.000). Conclusion: This study reports that Mycobacterium tuberculosis DNA can be detected in stool using Xpert testing with a higher sensitivity. Therefore stool which can easily be obtained is an appropriate alternative sample for the diagnosis of PTB using Xpert assay for children unable to give respiratory samples. Furthermore Xpert turn round time is less than 2 hours.

Xpert MTB/RIF与结核分枝杆菌利福平耐药表型检测一致性分析

目的探讨Xpert MTB/RIF和表型药物敏感性试验(pDST)检测结核分枝杆菌(MTB)利福平(RFP)耐药性结果的一致性,以及产生不一致结果的原因。方法对2020年云南省耐药监测中行Xpert MTB/RIF检测的672株MTB进行比例法pDST,对2种方法结果不一致的菌株进行全基因组测序(WGS)。结果以pDST结果为标准,XpertMTB/RIF检测MTBRFP耐药的敏感性为94.44%,特异性为97.32%,阳性预测值为66.67%,阴性预测值为99.52%。672株MTB中,有19株(2.83%)Xpert MTB/RIF与pDST检测结果不一致。2株Xpert MTB/RIF显示RFP敏感,pDST显示RFP耐药菌株中,未检出耐药突变1株,检出rpoB-Ile491Phe突变1株;17株Xpert MTB/RIF显示RFP耐药,pDST显示RFP敏感菌株均发现RFP耐药相关突变。Xpert MTB/RIF与pDST检测结果不一致的19株MTB均未发现明显的异质性耐药情况。结论Xpert MTB/RIF与pDST检测MTB RFP耐药结果一致性较好。结果不一致的主要原因为pDST结果的不稳定性、部分rpoB基因突变与RFP耐药相关性差,以及少数菌株发生了Xpert MTB/RIF靶点以外的其他罕见突变。