Performance of Xpert MTB/RIF in diagnosis of lymphatic tuberculosis from fresh and formaldehyde-fixed and paraffin embedded lymph nodes

Huang, Shaojun; Qin, Ming; Shang, Yuanyuan; Fu, Yuhong; Liu, Zichen; Dong, Yujie; Che, Nanying; Han, Yi; Guo, Zhanlin

doi:10.1016/j.tube.2020.101967

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…TB is characterized pathologically by granulomatous inflammation, which is typically consist of central caseous necrosis and surrounding fibrocytes and lymphocytes [28]. Previous studies have confirmed that FFPE specimen has excellent performance in the molecular diagnosis of DR-TB [29,30].…”

Section: Discussionmentioning

confidence: 99%

Drug Resistance and Molecular Characteristics of Mycobacterium tuberculosis: A Single Center Experience

Chen

Feng

et al. 2022

JPM

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In recent years, the incidence of tuberculosis (TB) and mortality caused by the disease have been decreasing. However, the number of drug-resistant tuberculosis patients is increasing rapidly year by year. Here, a total of 380 Mycobacterium tuberculosis (MTB)-positive formalin-fixed and paraffin-embedded tissue (FFPE) specimens diagnosed in the Department of Pathology of the Eighth Medical Center, Chinese PLA General Hospital were collected. Among 380 cases of MTB, 85 (22.37%) were susceptible to four anti-TB drugs and the remaining 295 (77.63%) were resistant to one or more drugs. The rate of MDR-TB was higher in previously treated cases (52.53%) than in new cases [(36.65%), p < 0.05]. Of previously treated cases, the rate of drug resistance was higher in females than in males (p < 0.05). Among specimens obtained from males, the rate of drug resistance was higher in new cases than in previously treated cases (p < 0.05). Of mutation in drug resistance-related genes, the majority (53/380, 13.95%) of rpoB gene carried the D516V mutation, and 13.42% (51/380) featured mutations in both the katG and inhA genes. Among the total specimens, 18.68% (71/380) carried the 88 M mutation in the rpsL gene, and the embB gene focused on the 306 M2 mutation with a mutation rate of 19.74%. Among the resistant INH, the mutation rate of −15 M was higher in resistance to more than one drug than in monodrug-resistant (p < 0.05). In conclusion, the drug resistance of MTB is still very severe and the timely detection of drug resistance is conducive to the precise treatment of TB.

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Section: Discussionmentioning

confidence: 99%

Drug Resistance and Molecular Characteristics of Mycobacterium tuberculosis: A Single Center Experience

Chen

Feng

et al. 2022

JPM

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“…Sensitivities of Xpert ® MTB/RIF and its ultra version reported in fresh non-FFPE clinical samples, so far, are always higher than 60% ( Tortoli et al, 2012 ; Sauzullo et al, 2016 ; Lee et al, 2017 ; Bahr et al, 2018 ; Dorman et al, 2018 ; Sarfaraz et al, 2018 ; Sulis et al, 2018 ; Aydemir et al, 2019 ; Kohli et al, 2021 ) and can reach more than 90% only in some body districts ( Mazzola et al, 2016 ). The few data available regarding the Xpert assay performances in FFPE samples are based on a few clinical biopsies and reported a wide range of sensitivities, which were not even concordant (from 97.6% in the case of the Ultra version to 53.2% in the case of the first MTB/RIF assay) ( Seo et al, 2014 ; Du et al, 2019 ; Njau et al, 2019 ; Budvytiene and Banaei, 2020 ; Huang et al, 2020 ). Some of these reports also suggest different sensitivities against the sites of biopsies (i.e., lymph node vs. non-lymph nodes sites) ( Polepole et al, 2017 ).…”

Section: Discussionmentioning

confidence: 99%

Rapid Detection and Quantification of Mycobacterium tuberculosis DNA in Paraffinized Samples by Droplet Digital PCR: A Preliminary Study

et al. 2021

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Background: Rapid and reliable diagnosis of tuberculosis (TB) represents a diagnostic challenge in compartmentalized extrapulmonary TB infection because of the small number of mycobacteria (MTB) and the frequent lack of fresh samples to perform culture. Here, we estimate the performances of homemade droplet digital PCR (ddPCR)-based assays against culture in 89 biopsies, for those fresh and formalin-fixed and paraffin-embedded (FFPE) subsamples were available.Methods: MTB diagnosis in fresh subsamples was performed by culture. Fresh subsamples were also analyzed for acid-fast bacilli smear-microscopy (AFB) and Xpert® MTB/RIF (Xpert). MTB examination was repeated in blind in the 89 FFPE subsamples by in-house ddPCR assays targeting the IS6110 and rpoB. Analytical sensitivity of ddPCR assays was evaluated using serial dilution of H37Rv strain. Limit of detection (LOD) was calculated by probit analysis. Results were expressed in copies/106 cells.Results: IS6110 and rpoB ddPCR assays showed a good linear correlation between expected and observed values (R2: 0.9907 and 0.9743, respectively). Probit analyses predicted a LOD of 17 and 40 copies/106 cells of MTB DNA for IS6110 and rpoB, respectively. Of the 89 biopsies, 68 were culture positive and 21 were culture negative. Considering mycobacterial culture as reference method, IS6110 assay yielded positive results in 67/68 culture-positive samples with a median interquartile range (IQR) of 1,680 (550–8,444) copies/106 cells (sensitivity: 98.5%; accuracy: 98.9). These performances were superior to those reported by the rpoB assay in FFPE subsamples (sensitivity: 66.20%; accuracy: 74.1) and even superior to those reported by Xpert and AFB in fresh subsamples (sensitivity: 79.4 and 33.8%, respectively; accuracy: 84.3 and 49.4, respectively). When Xpert and AFB results were stratified according to mycobacterial load detected by rpoB and IS6110 ddPCR, bacterial load was lower in Xpert and AFB negative with respect to Xpert and AFB-positive samples (p = 0.003 and 0.01 for rpoB and p = 0.01 and 0.11 for IS6110), confirming the poor sensitivity of these methods in paucibacillary disease.Conclusion: ddPCR provides highly sensitive, accurate, and rapid MTB diagnosis in FFPE samples, as defined by the high concordance between IS6110 assay and culture results. This approach can be safely introduced in clinical routine to accelerate MTB diagnosis mainly when culture results remain unavailable.

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“…② The bacteria are cultured on Löwenstein–Jensen (L-J) medium, incubated at 37°C with daily examinations for 8 weeks until the sample isolates at most minuscule one Mycobacterium tuberculosis complex colony, which is defined as positive. ③ After adding the corresponding reagent of GeneXpert MTB/RIF (Xpert, Cepheid, Sunnyvale, CA, USA), the sample was processed according to the manufacturer's instructions, and finally put into the machine to read the results ( 12 ).…”

Section: Methodsmentioning

confidence: 99%

Transmission of tuberculosis in an incarcerated population during the subclinical period: A cross-sectional study in Qingdao, China

Wang

Song

et al. 2023

Front. Public Health

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ObjectivesAs a closed gathering place, prison is the cradle of tuberculosis (TB) outbreak. Therefore, the analysis of the prevalence rate and risk factors of latent tuberculosis infection (LTBI) in prison will be a necessary measure to intervene in the spread of tuberculosis.MethodsIn this study, we consecutively recruited 506 adult prisoners in Qingdao to carry out this cross-sectional study. TB and LTBI were screened by IGRA, X-ray, X-pert, sputum smear and culture.ResultsA total of 17 TB, 101 LTBI and 388 HC were identified, with an infection rate of 23.32% (118/506) and a TB incidence rate of 3282/100,000 population. Age, malnutrition and inmates living with TB prisoners were risk factors for LTBI. Additionally, most TB cases (70.59%, 12/17) were subclinical tuberculosis (STB), contributing significantly to TB transmission.ConclusionOur results demonstrate that the transmission efficiency of asymptomatic patients is not essentially different from that of symptomatic patients, indicating that TB transmission occurs during the subclinical period. Our findings highlight the need to strengthen active case-finding strategies to increase TB case detection in this population.

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Performance of Xpert MTB/RIF in diagnosis of lymphatic tuberculosis from fresh and formaldehyde-fixed and paraffin embedded lymph nodes

Cited by 6 publications

References 7 publications

Drug Resistance and Molecular Characteristics of Mycobacterium tuberculosis: A Single Center Experience

Drug Resistance and Molecular Characteristics of Mycobacterium tuberculosis: A Single Center Experience

Rapid Detection and Quantification of Mycobacterium tuberculosis DNA in Paraffinized Samples by Droplet Digital PCR: A Preliminary Study

Transmission of tuberculosis in an incarcerated population during the subclinical period: A cross-sectional study in Qingdao, China

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