Paradigm for diagnosing mycobacterial disease: direct detection and differentiation of Mycobacterium tuberculosis complex and non-tuberculous mycobacteria in clinical specimens using multiplex real-time PCR

2018 ◽  
Vol 71 (9) ◽  
pp. 774-780 ◽  
Author(s):  
Jeong-Uk Kim ◽  
Dae-Shick Ryu ◽  
Choong-Hwan Cha ◽  
Seon-Hee Park

AimsMycobacterium tuberculosis and non-tuberculous mycobacteria (NTM) are clinically different, and the rapid detection and differentiation of M. tuberculosis complex (MTBC) and NTM is crucial for patient management and infection control. Given the slow growth of most pathogenic mycobacteria, nucleic acid amplification assays are excellent tools for direct identification of mycobacteria in clinical specimens. Recently, a multiplex real-time PCR assay was developed that can directly detect 20 mycobacterial species in clinical specimens. Here, we evaluated the diagnostic performance of the assay for diagnosing mycobacterial disease under routine laboratory conditions.MethodsA total of 3334 specimens collected from 1437 patients suspected of tuberculosis infection were subjected to acid-fast bacilli staining, conventional culture and the multiplex real-time PCR assay. To evaluate the sensitivity and specificity of the assay, the overall diagnosis of tuberculosis was defined by positive culture plus medical history, and the 2007 American Thoracic Society and Infectious Disease Society of America diagnostic criteria for NTM disease were applied.ResultsThe sensitivity, specificity, positive predictive value and negative predictive value were 87.5%, 99.6%, 96.1% and 98.5%, respectively, for the detection of MTBC isolates and 53.3%, 99.9%, 95.2%, and 98.9%, respectively, for detecting NTM isolates.ConclusionsThus, the assay can correctly differentiate between MTBC and NTM isolates in clinical specimens and would be a useful tool for the rapid differentiation of tuberculosis and NTM disease, despite its limited sensitivity for the diagnosis of NTM disease.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chien-Ru Lin ◽  
Hsin-Yao Wang ◽  
Ting-Wei Lin ◽  
Jang-Jih Lu ◽  
Jason Chia-Hsun Hsieh ◽  
...  

AbstractThe Mycobacterium tuberculosis complex (MTBC) remains one of the top 10 leading causes of death globally. The early diagnosis of MTBC can reduce mortality and mitigate disease transmission. However, current nucleic acid amplification diagnostic test methods are generally time-consuming and show suboptimal diagnostic performance, especially in extrapulmonary MTBC samples or acid-fast stain (AFS)-negative cases. Thus, development of an accurate assay for the diagnosis of MTBC is necessary, particularly under the above mentioned conditions. In this study, a single-tube nested real-time PCR assay (N-RTP) was developed and compared with a newly in-house-developed high-sensitivity real-time PCR assay (HS-RTP) using 134 clinical specimens (including 73 pulmonary and 61 extrapulmonary specimens). The amplification efficiency of HS-RTP and N-RTP was 99.8% and 100.7%, respectively. The sensitivity and specificity of HS-RTP and N-RTP for the diagnosis of MTBC in these specimens were 97.5% (77/79) versus 94.9% (75/79) and 80.0% (44/55) versus 89.1% (49/55), respectively. The sensitivity and specificity of HS-RTP and N-RTP for the diagnosis of MTBC in pulmonary specimens were 96.3% (52/54) versus 96.3% (52/54) and 73.7.0% (14/19) versus 89.5% (17/19), respectively; in extrapulmonary specimens, the sensitivity and specificity of HS-RTP and N-RTP were 100% (25/25) versus 92% (23/25) and 83.3% (30/36) versus 88.9% (32/36), respectively. Among the AFS-negative cases, the sensitivity and specificity of HS-RTP and N-RTP were 97.0% (32/33) versus 90.9% (30/33) and 88.0% (44/50) versus 92.0% (46/50), respectively. Overall, the sensitivity of HS-RTP was higher than that of N-RTP, and the performance was not compromised in extrapulmonary specimens and under AFS-negative conditions. In contrast, the specificity of the N-RTP assay was higher than that of the HS-RTP assay in all types of specimens. In conclusion, the HS-RTP assay would be useful for screening patients suspected of exhibiting an MTBC infection due to its higher sensitivity, while the N-RTP assay could be used for confirmation because of its higher specificity. Our results provide a two-step method (screen to confirm) that simultaneously achieves high sensitivity and specificity in the diagnosis of MTBC.


PLoS ONE ◽  
2015 ◽  
Vol 10 (11) ◽  
pp. e0143444 ◽  
Author(s):  
Yong Zhao ◽  
Guilian Li ◽  
Chongyun Sun ◽  
Chao Li ◽  
Xiaochen Wang ◽  
...  

2021 ◽  
Author(s):  
Masaaki Muraoka ◽  
Kazunori Sohma ◽  
Osamu Kawaguchi ◽  
Mikio Mizukoshi

ABSTRACTAs WHO reported, four curable STIs-chlamydia, gonorrhoea, syphilis and trichomoniasis occur more than 1 million per each day globally almond 2016. For this reason, it is important to control these STIs, one of which is “to detect”. The general methods in order to detect STIs are nucleic acid amplification tests (NAATs). One of the reasons why NAATs are utilized in many tests is that it is possibly to be more sensitive than other test. However, there needs to treat extraction of nucleic acids in advance and amplify specific regions by NAATs, and hence it must take much labour and much time. In this work, for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Treponema pallidum (TP) which is each etiological agent of chlamydia, gonorrhoea and syphilis, we evaluate and propose “quicker and simpler” NAATs. Specifically, utilizing mobile real-time PCR device “PCR1100” and PCR reagent kit “KAPA3G Plant PCR Kit”, it was considered whether real-time direct PCR could be performed or not without treating DNA extraction in advance so-called “direct”.As a result, firstly, we established that real-time direct PCR could be performed in all of CT, NG, and TP, and moreover, each Ct value correlated with the concentration of each organism similarly to detection of genome DNA (each correlation coefficient R2 > 0.95). Moreover, each assay demonstrated a limit of detection (LOD) of the follows; CT was 10^0.86 = 7.24 IFU/reaction, NG was 10^-0.19 = 0.65 CFU/reaction, and TP was 10^1.4 = 25.1 organisms/reaction. However, it appeared the sensitivity was a little low, especially for CT and TP.Secondly, we found that even as without treating sample in advance, the time of detection was required more less 15 minutes at any of case, which was very quick compared with other current methods for real-time PCR. Additionally, compared with other commercial devices, it was easier to operate the PCR1100 device, for example, start, analysis of Ct value.In conclusion, the present study has demonstrated that it is possible for real-time direct PCR to perform with combination of the PCR1100 device and the PCR reagent kit in 3 kinds of microorganisms-CT, NG and TP. Furthermore, we propose “quicker and simpler” methods for NAATs, which it would not take labour and time. Further studies are needed in order to contribute to control STIs.


2013 ◽  
Vol 114 (4) ◽  
pp. 1103-1108 ◽  
Author(s):  
L.A.S. Lira ◽  
F.C.F. Santos ◽  
M.S.Z. Carvalho ◽  
R.A. Montenegro ◽  
J.F.C. Lima ◽  
...  

2018 ◽  
Vol 56 (7) ◽  
pp. 1133-1139 ◽  
Author(s):  
Hanah Kim ◽  
Mina Hur ◽  
Eunsin Bae ◽  
Kyung-A Lee ◽  
Woo-In Lee

Abstract Background: Hepatitis B virus (HBV) nucleic acid amplification testing (NAAT) is important for the diagnosis and management of HBV infection. We evaluated the analytical performance of the cobas HBV NAAT (Roche Diagnostics GmbH, Mannheim, Germany) on the cobas 4800 System in comparison with COBAS AmpliPrep/COBAS TaqMan HBV Test (CAP/CTM HBV). Methods: Precision was evaluated using three levels of cobas HBV/HCV/HIV-1 Control Kit, and linearity was evaluated across the anticipated measuring range (10.0–1.0×109 IU/mL) at seven levels using clinical samples. Detection capability, including limit of blank (LOB), limit of detection (LOD) and limit of quantitation (LOQ), was verified using the 4th WHO International Standard for HBV DNA for NAT (NIBSC code: 10/266). Correlation between the two systems was compared using 205 clinical samples (102 sera and 103 EDTA plasma). Results: Repeatability and total imprecision (coefficient of variation) ranged from 0.5% to 3.8% and from 0.5% to 3.5%, respectively. Linearity (coefficient of determination, R2) was 0.999. LOB, LOD and LOQ were all acceptable within the observed proportion rate (85%). Correlation was very high between the two systems in both serum and plasma samples (correlation coefficient [r]=0.995). Conclusions: The new cobas HBV real-time PCR assay on the cobas 4800 System showed reliable analytical performances.


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