scholarly journals Prospective evaluation of BDProbeTec strand displacement amplification (SDA) system for diagnosis of tuberculosis in non-respiratory and respiratory samples

2004 ◽  
Vol 53 (12) ◽  
pp. 1215-1219 ◽  
Author(s):  
T D McHugh ◽  
C F Pope ◽  
C L Ling ◽  
S Patel ◽  
O J Billington ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Clinical Diagnosis ◽  
Nucleic Acid Amplification ◽  
Prospective Evaluation ◽  
Strand Displacement ◽  
Strand Displacement Amplification ◽  
Fine Needle ◽  
Fine Needle Aspirates ◽  
Time To Diagnosis ◽  
Smear Negative

Nucleic acid amplification techniques (NAATs) have been demonstrated to make significant improvements in the diagnosis of tuberculosis (TB), particularly in the time to diagnosis and the diagnosis of smear-negative TB. The BD ProbeTec strand displacement amplification (SDA) system for the diagnosis of pulmonary and non-pulmonary tuberculosis was evaluated. A total of 689 samples were analysed from patients with clinically suspected TB. Compared with culture, the sensitivity and specificity for pulmonary samples were 98 and 89 %, and against final clinical diagnosis 93 and 92 %, respectively. This assay has undergone limited evaluation for non-respiratory samples and so 331 non-respiratory samples were tested, identifying those specimens that were likely to yield a useful result. These were CSF (n = 104), fine needle aspirates (n = 64) and pus (n = 41). Pleural fluid (n = 47) was identified as a poor specimen. A concern in using the SDA assay was that low-positive samples were difficult to interpret; 7.8 % of specimens fell into this category. Indeed, 64 % of the discrepant results, when compared to final clinical diagnosis, could be assigned as low-positive samples. Specimen type did not predict likelihood of a sample being in the low-positive zone. Although the manufacturers do not describe the concept of a low-positive zone, we have found that it aids clinical diagnosis.

Isothermal strand displacement amplification (iSDA): a rapid and sensitive method of nucleic acid amplification for point-of-care diagnosis

The Analyst ◽  
2015 ◽  
Vol 140 (22) ◽  
pp. 7540-7549 ◽  
Author(s):  
Bhushan J. Toley ◽  
Isabela Covelli ◽  
Yevgeniy Belousov ◽  
Sujatha Ramachandran ◽  
Enos Kline ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Kinetic Model ◽  
Point Of Care ◽  
Reaction Network ◽  
Dna Amplification ◽  
Nucleic Acid Amplification ◽  
Strand Displacement ◽  
Strand Displacement Amplification ◽  
Simple Kinetic Model ◽  
Sensitive Method

A new rapid and sensitive method of isothermal DNA amplification and a simple kinetic model of this reaction network.

scholarly journals Cartridge based nucleic acid amplification test: a sensitive diagnostic tool for tuberculosis on fine needle aspirates samples

2020 ◽  
Vol 7 (4) ◽  
pp. 1511
Author(s):  
Suwarna B. Patil ◽  
Shweta M. Dhage ◽  
Pradeep S. Umap ◽  
S. V. Ghorpade ◽  
Shyamkant Patharwat
Keyword(s):  
Nucleic Acid ◽  
Correct Diagnosis ◽  
Extrapulmonary Tuberculosis ◽  
Needle Aspiration ◽  
Epithelioid Cell ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Cross Sectional ◽  
Fine Needle ◽  
Fine Needle Aspirates

Background: The extrapulmonary tuberculosis (EPTB) is challenging to diagnose due to its pauci-bacillary nature. According to recent research, WHO recommends cartridge based nucleic acid amplification test (CBNAAT) to be used as initial diagnostic test in suspected cases of extrapulmonary tuberculosis. Aim of the present study is to assess the role of CBNAAT in comparison with cytomorphological features upon fine needle aspiration cytology (FNAC) and Ziehl-Neelson (ZN) stain in clinically suspected cases of EPTB.Methods: Present pilot study is descriptive cross-sectional study of 439 cases of clinically suspected EPTB over a period of 12 months (January 2019 to December 2019). After procedure of fine needle aspirates, smears were stained with routine H&E, papanicolaou stain and ZN stain. In the same setting, aspirate was also sent for CBNAAT. Results were obtained after detailed study.Results: Out of 439 cases, presumptive tuberculosis was diagnosed in 192 cases showing either epithelioid cell granulomas or caseous necrosis or both upon morphology, while overall 94 cases were positive on ZN stain and 146 cases were CBNAAT positive with the sensitivity of 84.04% and specificity of 80.57%.Conclusions: FNAC is the cheapest and simplest method to diagnose extrapulmonary tuberculosis, however those smears where tuberculosis cannot be diagnosed on FNAC like suppurative lesions, reactive lymphadenitis and low cellularity, CBNAAT plays a key role for the correct diagnosis thereby significantly reducing the morbidity and mortality. 

Can nucleic acid amplification tests be used to test for chlamydia and gonorrhoea in microbicide trials?

2007 ◽  
Vol 18 (8) ◽  
pp. 543-545
Author(s):  
Patricia Rizzo-Price ◽  
Paul D Stamper ◽  
Billie Jo Wood ◽  
Steven J Reynolds ◽  
Thomas C Quinn ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Nucleic Acid ◽  
Nucleic Acid Amplification ◽  
Urine Samples ◽  
Strand Displacement ◽  
Inhibitory Effects ◽  
Strand Displacement Amplification ◽  
Nucleic Acid Amplification Tests ◽  
No Inhibition ◽  
Topical Microbicides

Microbicides may interfere with detection of Chlamydia trachomatis ( Ct) and Neisseria gonorrhoeae ( Ng) in urine samples from women who use microbicides. The inhibitory effects of BufferGel, PRO2000 and PRO2000 placebo, in urine samples, were determined by nucleic acid amplification tests (NAATs). Uninfected urine was inoculated with different concentrations (105–101 organisms/mL); microbicides were added to achieve final concentrations from 5% to 0.1%. Specimens were tested using strand displacement amplification (SDA) for Ct and Ng. Samples with BufferGel demonstrated no inhibition. Samples with PRO2000 showed inhibition at the 5% concentration when tested for Ct, whereas for Ng, PRO2000 showed inhibition at 5%, 2% and some 1% concentrations. The placebo showed no inhibition when detecting Ct, and variable inhibition at the 5% and 2% concentrations for Ng. The potential inhibitory effects of microbicides on the NAATs selected for detection of Ct and Ng should be considered in clinical trials involving topical microbicides.

scholarly journals A Retrospective Cross-Sectional Study of the Utility of Cartridge-Based Nucleic Acid Amplification Test in Diagnosis of Pulmonary and Extrapulmonary Tuberculosis in People Living with HIV in Second Highest HIV Prevalent State in India

2021 ◽  
Author(s):  
Tade Bagbi ◽  
Ningthoukhongjam Reema ◽  
S. Bhagyabati Devi ◽  
Thangjam Gautam Singh ◽  
Mohammad Jaleel ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Cross Sectional Study ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Rifampicin Resistance ◽  
Sputum Smear ◽  
Smear Microscopy ◽  
Sectional Study ◽  
Cross Sectional ◽  
Smear Negative

Abstract Introduction Tuberculosis (TB) in people living with human immunodeficiency virus (PLHIV) is difficult to diagnose due to fewer organisms in sputum and extrapulmonary samples. Sputum culture takes 4 to 8 weeks for growth of the mycobacteria. Delayed treatment for TB in PLHIV leads to increased mortality. This study evaluated cartridge-based nucleic acid amplification test (CBNAAT) as a diagnostic tool for diagnosis of pulmonary TB (PTB) and extrapulmonary TB (EPTB) in PLHIV in the second most HIV prevalent state in India and for comparing its efficacy between Ziehl–Neelsen (ZN) staining sputum smear–positive and sputum smear–negative TB. Methods This cross-sectional study was conducted in RIMS, Imphal, with 167 PLHIV patients, age 15 years or older, having signs and symptoms of TB. Appropriate samples for sputum microscopy and CBNAAT were sent. Conclusion The overall sensitivity of sputum smear for acid-fast bacillus (AFB) was found to be 30.71% and that of CBNAAT was 38.57%. Sensitivity of CBNAAT for sputum smear–positive and sputum smear–negative TB was 100 and 11.3%, respectively. Sensitivity of ZN smear for AFB of EPTB sample was 48.1% and that of CBNAAT was 59.25%. In both PTB and EPTB, CBNAAT showed an increase in diagnosis of microbiologically confirmed PTB cases by 7.8 and 11.1%, respectively, over and above the cases diagnosed by ZN smear microscopy. Rifampicin resistance was detected in five patients. We conclude that CBNAAT is a rapid test with better sensitivity in diagnosis of PTB and EPTB in PLHIV, compared with ZN smear microscopy. It detects rifampicin resistance for multidrug-resistant TB and helps in early treatment intervention.

Mycoplasmas

2020 ◽  
pp. 1295-1306
Author(s):  
Jørgen Skov Jensen ◽  
David Taylor-Robinson
Keyword(s):  
Nucleic Acid ◽  
Supportive Care ◽  
Outer Membrane ◽  
Clinical Diagnosis ◽  
Cell Walls ◽  
Macrolide Resistance ◽  
Nucleic Acid Amplification ◽  
Effective Vaccine ◽  
Nucleic Acid Amplification Tests ◽  
Gain Access

Mycoplasmas are the smallest self-replicating prokaryotes. They are devoid of cell walls, with the plasticity of their outer membrane favouring pleomorphism, although some have a characteristic flask-shaped appearance. Mycoplasmas recovered from humans belong to the genera Mycoplasma (14 species and one candidatus species) and Ureaplasma (two species). They are predominantly found in the respiratory and genital tracts, but sometimes invade the bloodstream and thus gain access to joints and other organs. Diagnosis is made by nucleic acid amplification tests and/or serology. Culture is slow and of limited value in clinical diagnosis. Apart from supportive care, treatment is usually with tetracyclines or macrolides, although an increasing prevalence of macrolide resistance is seen, primarily in Asia. There is no commercially available effective vaccine.

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