Quantitative Real-Time PCR (Q-Pcr) for Sputum Smear Diagnosis of Pulmonary Tuberculosis Among People With Hiv/Aids

Abstract

Objective: To assess quantitative real-time polymerase chain reaction (q-PCR) for the sputum smear diagnosis of pulmonary tuberculosis (PTB) in patients living with HIV/AIDS with a clinical suspicion of PTB. Method: This is a prospective study to assess the accuracy of a diagnostic test, conducted on 140 sputum specimens from 140 patients living with HIV/AIDS with a clinical suspicion of PTB, attended at two referral hospitals for people living with HIV/AIDS in the city of Recife, Pernambuco, Brazil. A Löwenstein-Jensen medium culture and 7H9 broth were used as gold standard. Results: Of the 140 sputum samples, 47 (33.6%) were positive with the gold standard. q-PCR was positive in 42 (30%) of the 140 patients. Only one (0.71%) did not correspond to the culture. The sensitivity, specificity and accuracy of the q-PCR were 87.2%, 98.9% and 95% respectively. In 39 (93%) of the 42 q-PCR positive cases, the CT (threshold cycle) was equal to or less than 37. Conclusion: q-PCR performed on sputum smears from patients living with HIV/AIDS demonstrated satisfactory sensitivity, specificity and accuracy, and may therefore be recommended as a method for diagnosing PTB.

Evaluation of four molecular methods for the diagnosis of tuberculosis in pulmonary and blood samples from immunocompromised patients

“…For TB detection in sputum, our qPCR assay presented 100% sensitivity and 96.7% specificity, comparable to the sensitivity of 80-95% and the specificity of 95-100% reported by others who also developed the TaqMan assay for detection of the IS6110 element ( Gomez et al 2011 , Lira et al 2013 , Albuquerque et al 2014 ). qPCR was positive for 100% of the smear-negative, culture-positive patients, providing earlier TB diagnosis for more TB-suspected patients than smear-based microscopy (7% vs. 4%) in HIV-infected patients.…”

Effectiveness of real-time polymerase chain reaction assay for the detection of Mycobacterium tuberculosis in pathological samples: a systematic review and meta-analysis

“…1 ). Twenty-one [ 10 , 24 , 25 , 27 , 29 , 31 , 32 , 39 , 44 , 45 , 47 , 49 , 51 , 52 , 54 , 57 , 60 , 61 , 64 , 66 , 67 ] reported detection of pulmonary TB (PTB), fifteen [ 23 , 30 , 33 , 35 , 37 , 38 , 40 – 42 , 50 , 53 , 55 , 56 , 59 , 62 ] reported detection of extra-pulmonary TB (EPTB) and ten [ 26 , 28 , 34 , 36 , 43 , 46 , 48 , 58 , 63 , 65 ] reported on both types of pathological sample. Table 1 summarises the main characteristics of the included studies.…”

Use of Digital Droplet PCR to Detect Mycobacterium tuberculosis DNA in Whole Blood-Derived DNA Samples from Patients with Pulmonary and Extrapulmonary Tuberculosis

“…Real-time PCR and a newer assay named the Xpert MTB/rifampin (RIF) assay (which is based on real-time PCR) have been widely used for the clinical diagnostic of MTB (Lawn and Zumla, 2012 ; Albuquerque et al, 2014 ). However, real-time PCR relies on a calibration curve to calculate the MTB DNA copy number, which results in a highly complicated diagnostic process that requires that researchers spend a large amount of time customizing MTB standards in order to develop the calibration curve.…”

“…The confirmed diagnoses were based on a systematical analysis and integration of patients' medical history, current clinical symptoms, physical signs, imaging technologies (X-ray, computed tomography [CT], and positron emission tomography [PET]), molecular diagnostics (PCR and qPCR), microbiological examinations (BD Bactec MGIT 960 bacterial culture for samples with different resources and specimen smear staining), and immunological methods (interferon-gamma release assays and/or tuberculin skin tests). According to the WHO TB case definition criteria, the patients included in our study were divided into two groups: new cases of TB and cases of TB involving retreatment (Albuquerque et al, 2014 ). The general patient information of the patients included in our study is summarized in Table 1 .…”

“…X52471) is a specific MTB DNA insert sequence which was found in 1990. Currently, it is regarded as an ideal target sequence of MTB nuclear acid diagnosis (Mcadam et al, 1990 ; Thierry et al, 1990a , b ; Rao et al, 2009 ; Albuquerque et al, 2014 ; Hwang et al, 2015 ). We aimed to assess the capacity of ddPCR, in comparison to real-time PCR, for detecting very low levels of circulating MTB DNA.…”