Clinical Suspicion Of Pulmonary Tuberculosis Research Articles

Comparison of chest radiograph findings in ambulatory and hospitalized children with pulmonary tuberculosis.

The diagnosis ofchildhood tuberculosis (TB) is, in many instances, solely reliant on chest radiographs (CXRs), as they are often the only diagnostic tool available, especially in TB-endemic areas. Accuracy and reliability of CXRs for detecting TB lymphadenopathy may vary between groups depending on severity of presentation and presence of parenchymal disease, which may obscure visualization. To compare CXR findings in ambulatory versus hospitalized children with laboratory confirmed pulmonary TB versus other lower respiratory tract infections (LRTI) and test inter-rater agreement for these findings. Retrospective review, by two pediatric radiologists, of CXRs performed on children < 12years old referred for evaluation of LRTI with clinical suspicion of pulmonary TB in inpatient and outpatient settings. Each radiologist commented on imaging findings of parenchymal changes, lymphadenopathy, airway compression and pleural effusion. Frequency of imaging findings was compared between patients based on location and diagnosis and inter-rater agreement was determined. Accuracy of radiographic diagnosis was compared to laboratory testing which served as the gold standard. The number of enrolled patients was 181 (54% males); 69 (38%) were ambulatory and 112 (62%) were hospitalized. Of those enrolled, 87 (48%) were confirmed to havepulmonary TB, while 94 (52%) were other LRTI controls. Lymphadenopathy and airway compression were more common in TB patients than other LRTI controls, regardless of patient location. Parenchymal changes and pleural effusion were more common in hospitalized than ambulatory patients, regardless of patient diagnosis. Agreement for parenchymal changes was higher in the hospitalized group (kappa [κ] = 0.75), while agreement for lymphadenopathy (κ = 0.65) and airway compression (κ = 0.68) was higher in the ambulatory group. The specificity of CXRs for TB diagnosis (> 75%) was higher than the sensitivity (< 50%) for both ambulatory and hospitalized groups. Higher frequency of parenchymal changes among hospitalized children may conceal specific imaging findings of TB such as lymphadenopathy, contributing to the poor reliability of CXRs. Despite this, the high specificity of CXRs shown in our results is encouraging for continued use of radiographs for TB diagnosis in both settings.

Role of line probe assay in detection of Mycobacterium tuberculosis in children with pulmonary tuberculosis

BackgroundIndia is the highest TB burden country in the world with almost 27 lakh cases reported in 2019. Pediatric tuberculosis in India accounts for almost 31% of global TB burden. Despite such high mortality and morbidity in children, diagnosis of pulmonary TB in children still remains very challenging. Material and methodsThis cross-sectional study was conducted in a tertiary care hospital in Delhi, India. Children between 1 and 12 months with clinical suspicion of pulmonary tuberculosis who had not previously taken ATT were included.Early morning gastric aspirate samples were collected after overnight fasting, on two days. Both days sputum sample were subjected to sputum smear microscopy and one of the two samples was subjected to line probe assay (LPA), cartridge based nucleic acid amplification (CBNAAT) and mycobacterium growth in tube (MGIT-960). Results84 children with pulmonary tuberculosis were enrolled. The most common presenting complaint was fever seen in 83 patients (98.8%). Only 17 (20.24%) were sputum smear positive by Ziehl- Neelsen (ZN) staining. LPA was positive in 47 (55.95%) samples and among these positive samples both INH and RIF resistance was detected in 2 (4.26%) samples. CBNAAT was positive in 53 patients (63%). Growth in liquid culture media (MGIT 960) was observed in 44 (52.38%) samples. Among 17 smear positive samples, LPA was detected in 14 (82.35%) samples and among 67 smear negative sample LPA was detected in 33 (49.25%) samples. LPA had 63.46% sensitivity, 100% specificity in detecting mycobacterium tuberculosis. DiscussionWHO's recommendation for using LPAs has been limited to culture isolates or smear-positive sputum specimens. New data has since been generated on the use of LPAs as newer versions of LPA have been developed over past few years.Previous studies conducted using LPA version 1.0 reported much lower detection rate of mycobacterium tuberculosis in smear negative specimens.With the availability of newer versions such as Hain GenoTypeMTBDRplusversion 2 and Nipro NTM + MDRTB detection kit 2, the diagnostic utility of LPA may be enhanced.

Comparison of Light Emitting Diode (LED) Fluorescent Microscopy with Ziehl-Neelsen Microscopy on Sputum Specimens for Diagnosis of Pulmonary Tuberculosis Keeping Culture as ‘Gold Standard’

Objective: To compare LED fluorescence microscopy and Ziehl-Neelsen staining in terms of their diagnostic performance in diagnosing pulmonary tuberculosis, taking sputum specimens from patients suspected of pulmonary tuberculosis.&#x0D; Study Design: Prospective longitudinal study.&#x0D; Place and Duration of Study: Microbiology Department, Armed Forces Institute of Pathology Rawalpindi, from Jan 2019 to Dec 2019.&#x0D; Methodology: Sputum samples from patients with clinical suspicion of pulmonary tuberculosis were stained using Ziehl-Neelsen (ZN) stain, fluorescent stain with Auramine O staining (AO) stain and Mycobacterial culture on Mycobacterial Growth Indicator Tube (MGIT 960), to detect Mycobacterium tuberculosis. WHO guidelines were followed to grade positive smears.&#x0D; Results: Among 206 patients with suspicion of tuberculosis, 143 (69%) were male, and 63 (30%) were female patients. The mean age of the patients was 53.67 ± 14.73 years. Out of 206 sputum samples, 64 were negative by all three techniques used. 142 (68%) specimens detected Mycobacterium tuber-culosison MGIT960. Within 142 culture-positive samples, only 40 samples were positive on Ziehl-Neelsen microscopy, whereas 97 samples were detected positive by LED fluorescent microscopy. In culture-negative samples, three were missed on Ziehl-Neelsen staining, which was positive with Fluorescent microscopy. Sensitivity and specificity for Ziehl-Neelsen smear microscopy were 26.7% and 96.8%, respectively. Sensitivity and specificity for Fluorescent smear microscopy were 64.8% and 92.2%, respectively.&#x0D; Conclusion: We concluded that the efficacy of LED fluorescence microscopy has proven to have many potential advantages over conventional Ziehl-Neelsen microscopy.

MOLECULAR DETECTION OF INSERTION SEQUENCE 6110 OF MYCOBACTERIUM TUBERCULOSIS IN PATIENTS WITH PULMONARY TUBERCULOSIS AND TUBERCULOUS PLEURITIS IN ANBAR GOVERNORATE, WEST OF IRAQ

Accurate identification and early diagnosis of tuberculosis especially latent and active infection is the key to prevention of the disease. This study was conducted to detect the accuracy of conventional and real time polymerase chain reaction in the diagnosis of pulmonary tuberculosis caused by Mycobacterium tuberculosis in sputum and blood samples using 123 bp gene of repetitive insertion sequence 6110 (IS6110) of bacterial genome and tuberculous pleuritis using pleural effusion. Sixty five patients who have clinical suspicion of pulmonary tuberculosis, fifty patients with suspicion of TB pleurisy and twenty patients with non-tuberculous mycobacterial pulmonary disease as control were studied during the period from April, 2012 to December, 2015. They were admitted to Department of Internal Medicine in Ramadi Teaching Hospital and Clinical Private. EDTA-Peripheral blood and sputum samples had been taken from patient with pulmonary tuberculosis. Also, pleural effusion was obtained from patients with tuberculous pleuritis. They were subjected to DNA extraction, amplification of the target DNA by conventional PCR and qualitative real time PCR. Of the 65 sputum samples from patients with pulmonary tuberculosis, 37 (56.9%) were AFB smear-positive. Of these, 32 (86.5%) and ?? (94.6%) were positive for PCR and RTPCR respectively. Further, out of 28 negative smear, 7 (25%) and 8 (28.6%) smears were PCR and RTPCR positive respectively. Further, in peripheral blood based PCR study, out of 37 patients whose sputum were positive by AFB smear, only 25 (67.6%) of them were positive for PCR. Peripheral blood based PCR and RT-PCR essays were negative for all AFB smear negative cases. In suspected tuberculous pleuritis, 8 (16%), 9 (18%) patients reveal positive result for both of conventional and real time PCR respectively. Also, all twenty spontaneous sputum samples (controls)were negative for PCR. The study concluded that PCR provides a sensitive and specific means for laboratory diagnosis of pulmonary tuberculosis and qualitative real time PCR is a more confirmatory test but the molecular diagnosis of the tuberculosis should be based on the combined analysis of baciloscopia, clinical manifestations and therapeutic proves. Further, it was concluded that PCR and RT-PCR based- peripheral blood leukocytes is of little value for specific diagnosis of pulmonary tuberculosis. Regarding tuberculous pleuritis, PCR test revealed low sensitivity and high specificity using pleural fluid. The sensitivity was higher in cases in which the bacillary load was high-in acid fast bacilli-positive samples.

Comparison of conventional diagnostic methods with molecular method for the diagnosis of pulmonary tuberculosis

BackgroundTuberculosis remains one of the deadliest communicable diseases. Prompt diagnosis of active tuberculosis cases facilitates timely therapeutic intervention and minimizes the community transmission. Although conventional microscopy has low sensitivity, still it remains the corner stone for the diagnosis of pulmonary tuberculosis in high burden countries like India. On the other hand, Nucleic acid amplification techniques due to their rapidity and sensitivity, not only help in early diagnosis and management of tuberculosis but also curtail the transmission of the disease. This study therefore was aimed at assessing the diagnostic performance of Microscopy by Ziehl Neelsen (ZN) and Auramine Staining (AO) with Gene Xpert/CBNAAT (Cartridge based nucleic acid amplification test) in the diagnosis of Pulmonary Tuberculosis. MethodsA prospective comparative study was done on the sputum samples of 1583 adult patients from November 2018 to May 2020 suspected of having pulmonary tuberculosis as per NTEP criteria visiting the Designated Microscopic Centre of SGT Medical College, Budhera, Gurugram. Each sample was subjected to ZN staining, AO staining, and was run on CBNAAT as per National Tuberculosis Elimination Program (NTEP) guidelines. The sensitivity, specificity, PPV and NPV and Area under the curve of ZN microscopy and Fluorescent Microscopy were calculated taking CBNAAT as reference in absence of culture. ResultsOut of the 1583 samples studied, 145 (9.15%) and 197 (12.44%) were positive by ZN and AO staining methods respectively. By CBNAAT 246 (15.54%) samples were positive for M. tuberculosis. AO was also able to detect more pauci-bacillary cases than ZN. While CBNAAT detected M. tuberculosis in 49 sputum samples which were missed by both methods of microscopy. On the other hand there were 9 samples which were positive for AFB by both the smear microscopy techniques but M. tuberculosis was not detected by CBNAAT, these were considered as Non-Tuberculous Mycobacteria. Seventeen samples were resistant to rifampicin. ConclusionAuramine Staining technique is more sensitive and less time consuming for the diagnosis of pulmonary tuberculosis as compared to the conventional ZN Staining. CBNAAT can be a useful tool for early diagnosis of patients with high clinical suspicion of pulmonary tuberculosis and detecting rifampicin resistance.

Diagnostic performance of the Xpert MTB/RIF assay in BAL fluid samples from patients under clinical suspicion of pulmonary tuberculosis: a tertiary care experience in a high-tuberculosis-burden area

ABSTRACTObjective:To assess the diagnostic performance of the Xpert MTB/RIF assay, a rapid molecular test for tuberculosis, comparing it with that of AFB staining and culture, in BAL fluid (BALF) samples from patients with clinically suspected pulmonary tuberculosis (PTB) who are sputum smear-negative or produce sputum samples of insufficient quantity. Methods:This was a retrospective study of 140 cases of suspected PTB in patients who were smear-negative or produced insufficient sputum samples and were evaluated at a tertiary teaching hospital in the city of Rio de Janeiro, Brazil. All of the patients underwent fiberoptic bronchoscopy with BAL. The BALF specimens were evaluated by AFB staining, mycobacterial culture, and the Xpert MTB/RIF assay. Results:Among the 140 patients, results for all three microbiological examinations were available for 73 (52.1%), of whom 22 tested positive on culture, 17 tested positive on AFB staining, and 20 tested positive on the Xpert MTB/RIF assay. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for AFB staining were 68.1%, 96.1%, 88.2%, 87.5%, and 87.6%, respectively, compared with 81.8%, 96.1%, 90.0%, 92.4%, and 91.8%, respectively, for the Xpert MTB/RIF assay. The agreement between AFB staining and culture was 82.3% (kappa = 0.46; p < 0.0001), whereas that between the Xpert MTB/RIF assay and culture was 91.8% (kappa = 0.8; p < 0.0001). Conclusions:In BALF samples, the Xpert MTB/RIF assay performs better than do traditional methods, providing a reliable alternative to sputum analysis in suspected cases of PTB. However, the rate of discordant results merits careful consideration.

Evaluation of the performance of clinical predictors in estimating the probability of pulmonary tuberculosis among smear-negative cases in Northern Ethiopia: a cross-sectional study

ObjectivesTo evaluate the performance of the predictors in estimating the probability of pulmonary tuberculosis (PTB) when all versus only significant variables are combined into a decision model (1) among all...

A study to analyze the differences between GeneXpert MTB/RIF assay and LED fluorescent microscopy for the diagnosis of pulmonary tuberculosis in a tertiary care centre

cultures although being the gold standard for diagnosing tuberculosis has its limitations as it is time consuming. Thus newer methods using light-emitting diode fluorescent microscopy (LED-FM) and molecular methods like the GeneXpert MTB/RIF assay are being adopted as a mainstay for diagnosing tuberculosis around the globe. This observational descriptive study was carried out for a period of 21 months. Sputum samples from 110 adult subjects with a clinical suspicion of pulmonary tuberculosis (PTB) were stained for LED-FM microscopy and also inoculated into the GeneXpert assay. The positive smears were graded as per the Revised National Tuberculosis Control Programme (RNTCP) guidelines and positive GeneXpert assay results along with Rifampicin resistance were noted and analysed. Out of the 110 samples, (77.2%) were males and (22.7%) females. Of the 110 samples, 75 (68.1%) were positive for by the GeneXpert assay. In contrast with LED-FM, all 25 smear positive samples were also GeneXpert positive. Additionally, GeneXpert detected 10 smear negative cases. 10 (9%) positive GeneXpert isolates showed resistance to Rifampicin. The overall sensitivity of GeneXpert was greater but its specificity was comparable with LED-FM. The Xpert and LED-FM tests were comparable in specificity, but the GeneXpert assay out did the LED-FM as it was a more sensitive and rapid test for the diagnosis of tuberculosis and additionally detection of Rifampicin resistance. Our study fully agrees that the GeneXpert assay is a step ahead in the early diagnosis of tuberculosis even for smear negative cases of PTB. This assay is also a relatively simple and routine test that staff can perform with minimal training.

Frequency of Pulmonary Tuberculosis on high resolution computed tomography in clinically suspected patients visiting Radiology Department Mayo Hospital, Lahore.

High resolution computed tomography scan, in modern years, is more effective than standard computed tomography scan and conventional chest radiography in localization of diseases in the lobule of lung and in the appraisal of pulmonary parenchymal diseases because of high-resolution power and minimal partial volume effect. Objectives: To identify pulmonary tuberculosis in clinically suspected patients by high resolution computed tomography scan of chest. Study Design: Cross Sectional Descriptive study. Setting: Department of Radiology, Mayo Hospital, Lahore. Period: 15th February 2018 to 15th November 2018. Material &amp; Methods: After taking consent, fifty patients, fulfilling inclusion and exclusion criteria, were selected by convenient sampling in this cross sectional descriptive study. Demographic details, clinical history and High resolution tomographic scan findings were documented. Data analysis was performed on Microsoft excel and statistical package for social sciences (SPSS v21) and reported by descriptive statistics. Results: Out of 50 patients, pulmonary tuberculosis was diagnosed in 44(88%) patients, acute on chronic tuberculosis in 2(4%), healed tuberculosis in 2(4%), interstitial lung disease in 1(2%) &amp; post tubercular sequela in 1(2%) patient. Majority were males (n=29, 58%) and most patients belonged to fifth decade of life (n=19, 38%). Overall mean age of patients was 45.14±12.16 years and mostly belonged to lower socioeconomic status (n=38, 76%). Most common symptom and High resolution computed tomography finding were low grade fever in 45(95%) &amp; consolidation in 39(78%) patients, respectively. Conclusion: High resolution computed tomography scan is valuable in diagnosis of pulmonary tuberculosis &amp; its related spectrum of diseases in patients having clinical suspicion of pulmonary tuberculosis.

Lung ultrasonography in pulmonary tuberculosis: A pilot study on diagnostic accuracy in a high-risk population

ObjectivesThe validity of lung ultrasound (LUS) in the diagnosis of interstitial or focal lung pathologies is well documented, we assessed its accuracy in the diagnosis of pulmonary tuberculosis (PTB). MethodsSonographic signs suggestive of PTB and their diagnostic accuracy were evaluated in patients admitted with clinical suspicion of PTB. Consolidations, subpleural nodules, pleural thickenings or irregularities and pleural effusion were assessed. LUS signs significantly associated with PTB in the univariate analysis (p < .05) were entered in a multivariate logistic regression model. ResultsPTB was confirmed in 51 out of 102 patients. Multiple consolidations (OR 3.54, 95%CI 1.43–8.78), apical consolidations (OR 9.65, 95%CI 3.02–30.78), superior quadrant consolidations (OR 4.01, 95%CI 1.76–9.14), and subpleural nodules (OR 5.29, 95%CI 2.27–12.33) were significantly associated with PTB diagnosis. Apical consolidation (OR 9.67, 95%CI 2.81–33.25, p 0.003) and subpleural nodules (OR 5.30, 95%CI 2.08–13.52, p 0.005) retained a significant association in a multivariate model, with an overall accuracy of 0.799. ConclusionsOur data suggest a possible role of LUS in the diagnosis of PTB, a high burden pathological condition for which the delay in diagnosis still represents a critical point in the control of the disease.

Molecular diagnosis of multidrug-resistant tuberculosis in sputum samples by melting curve analysis

To analyze melting curves for the diagnosis of multidrug-resistant tuberculosis from sputum samples. Sputum samples (n = 250) were collected from patients with clinical suspicion of pulmonary tuberculosis as a result of bacilloscopy and cultured in solid medium Lowenstein Jensen. According to the reference method, 124 samples sensitive to rifampicin and isoniazid, 24 resistant to rifampicin, 33 resistant to isoniazid, and 69 multidrug-resistant were used. It was evaluated by real-time PCR and then by melting curves, the rpoB gene was used as a biomarker of rifampicin resistance, and the katG gene and inhA promoter region were used as biomarkers of isoniazid resistance. The H37Rv strain was considered a drug-sensitive control. The results of the reference method and the results of the melting curve analysis were compared to evaluate the parameters of sensitivity, specificity, positive predictive value and negative predictive value. Rifampicin resistance showed a sensitivity of 90.3%, specificity of 90.4%, positive predictive value of 84.8% and negative predictive value of 94.0%. Isoniazid resistance showed a sensitivity of 90.2%, specificity of 93.9%, positive predictive value of 91.1% and negative predictive value of 93.3%. The detection of multidrug-resistant tuberculosis showed values of 89.9%, 90.6%, 78.5% and 95.9% for sensitivity, specificity, positive predictive value and negative predictive value, respectively. The melting curve analysis showed to be safe and reliable to be used in the rapid diagnosis of multidrug-resistant tuberculosis in sputum samples.

Use of High-Resolution Computed Tomography (HRCT) in Diagnosis of Sputum Negative Pulmonary Tuberculosis.

To study the role of high-resolution computed tomography (HRCT) in the diagnosis of pulmonary tuberculosis (PTB) in sputum smear negative patients and to design HRCT criterion to forecast the threat of pulmonary tuberculosis. We studied 69 patients having sputum smear negative for acid-fast bacilli (AFB) but still with clinical suspicion of PTB after taking written informed consent. We studied their medical characteristics, numerous separate HRCT-results and combination of HRCT findings to foresee the danger for PTB by utilizing univariate and multivariate investigation. Temporary HRCT diagnostic criteria were planned in view of these outcomes to find out the risk of PTB and tested these criteria on our patients. Chronic cough and night sweats were highly linked to a greater risk of PTB among clinical features. On HRCT chest presence of cavity, centrilobular nodules, consolidation, ground glass opacity (GGO), lymphadenopathy, main lesion in S1, S2, S6, lobular consolidation, other minute nodules and tree in bud appearance was significantly linked to an elevated risk of PTB in linear regression analysis. While cavity, centrilobular nodules, interlobular septal thickening, pleural effusion and tree-in-bud appearance was significantly linked to a greater threat of PTB in multivariate regression analysis. Positioning of the patients utilizing our HRCT indicative criteria uncovered reliable sensitivity and specificity for PTB patients determining that HRCT is a useful tool in sputum negative PTB patients. HRCT is useful in selecting individuals with greater chances of PTB in the sputum smear-negative setting.

Comparative Study of GeneXpert with ZN Stain and Culture in Samples of Suspected Pulmonary Tuberculosis.

Tuberculosis remains one of the deadliest communicable diseases. There are number of tests available for the diagnosis of tuberculosis but conventional microscopy has low sensitivity and culture although gold standard, but takes longer time for positivity. On the other side, Nucleic acid amplification techniques due to its rapidity and sensitivity not only help in early diagnosis and management of tuberculosis especially in patients with high clinical suspicion like immunocompromised patients, history of contact with active tuberculosis patient etc., but also curtail the transmission of the disease. To evaluate the sensitivity, specificity, positive predictive value and negative predictive value of Nucleic acid amplification assay (GeneXpert) using respiratory samples in patients with suspected pulmonary tuberculosis and compare with AFB smear microscopy (Ziehl Neelsen stain) and Acid Fast Bacilli (AFB) culture. We retrospectively reviewed the respiratory samples of suspected pulmonary tuberculosis (including Bronchoalveolar lavage and sputum) of 170 patients from Jan 2015 to Nov 2015 for ZN stain, culture and GeneXpert (Xpert(®) MTB/Rif assay). The sensitivity, specificity, PPV and NPV of GeneXpert and ZN microscopy were calculated using Liquid culture of Mycobacterium tuberculosis as gold standard. A total of 170 patient samples were evaluated in final analysis. Of these, 14 samples were positive by all three methods used in our study. The overall sensitivity, specificity, PPV and NPV of GeneXpert were 86.8%, 93.1%, 78.5% and 96% respectively and for BAL sample, 81.4%, 93.4%, 73.3% and 95.7% respectively. The overall sensitivity and specificity of AFB smear microscopy were 22.2%, % and 78.5% respectively and for BAL sample 22.2% and 100% respectively. For AFB negative samples sensitivity and specificity were 79.1% and 93.1% respectively. GeneXpert has a higher sensitivity than AFB smear microscopy in respiratory samples. GeneXpert can be a useful tool for early diagnosis of patients with high clinical suspicion of pulmonary tuberculosis. Positive GeneXpert, but culture negative results should be read cautiously and be well correlated with clinical and treatment history of the patient. The other major advantage of Gene Xpert is that it simultaneously detects Rifampicin resistance and especially beneficial in patient with MDR and HIV associated tuberculosis and should be studied further.

Cost-effectiveness of point-of-care digital chest-x-ray in HIV patients with pulmonary mycobacterial infections in Nigeria.

BackgroundChest-x-ray is routinely used in the diagnosis of smear negative tuberculosis (TB). This study assesses the incremental cost per true positive test of a point-of-care digital chest-x-ray, in the diagnosis of pulmonary mycobacterial infections among HIV patients with presumed tuberculosis undetected by smear microscopy.MethodsConsecutive patients with clinical suspicion of pulmonary tuberculosis were serially tested for Human immunodeficiency virus (HIV), their sputum examined for Acid Fast Bacilli then cultured in broth and solid media. Cultures characterized as tuberculous (M.tb) and non-tuberculous (NTM) mycobacteria by Hain assays were used as gold standards. A chest-x-ray was classified as: (1) consistent for TB, (2) not consistent for TB and (3) no pathology.ResultsOf the 1391 suspected cases enrolled, complete data were available for 952 (68%): 753/952 (79%) had negative smear tests while 150/753 (20%) had cultures positive for TB. Of those, 82/150 (55%) had chest-x-ray signs consistent with TB and 29/82 (35%) were positive for HIV. Within the co-infected, 9/29 (31%) had NTM infections. Among all suspects, the cost per positive case detected using smear microscopy test was $52.84; the overall incremental cost per positive case using chest-x-ray in smear negatives was $23.42, and in smear negative, HIV positive patients the cost was $15.77.ConclusionPoint-of-care chest-x-ray is a cost-effective diagnostic tool for smear negative HIV positive patients with pulmonary mycobacterial infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0675-0) contains supplementary material, which is available to authorized users.

QUANTITATIVE REAL-TIME PCR (Q-PCR) FOR SPUTUM SMEAR DIAGNOSIS OF PULMONARY TUBERCULOSIS AMONG PEOPLE WITH HIV/AIDS

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.

Comparison of molecular and immunological methods for the rapid diagnosis of smear-negative tuberculosis

The rapid diagnosis of pulmonary tuberculosis (TB) can be challenging if acid-fast bacilli are not detected by sputum smear microscopy. To compare the results of the GeneXpert® MTB/RIF assay on a single sputum or bronchoalveolar lavage (BAL) specimen test with local immunodiagnosis from the site of disease using the T-SPOT®.TB assay on BAL (BAL T-SPOT). The Xpert and BAL T-SPOT tests were compared in 96 patients suspected of having sputum smear-negative pulmonary TB admitted to a referral centre in Germany. BAL T-SPOT identified 10 of 11 patients with pulmonary TB (including 3/4 patients with culture-confirmed TB) with a negative Xpert test. Using Xpert, the sensitivity, specificity and positive and negative likelihood ratios (LRs) were respectively 60.0%, 97.4%, 30.0% and 0.4% in culture-confirmed cases and 42.1%, 97.4%, 21.1% and 0.6% in all TB patients. In contrast, using BAL T-SPOT, the sensitivity, specificity and positive and negative LRs were respectively 80.0%, 62.6%, 2.1% and 0.3% in culture-confirmed cases and 89.4%, 62.6%, 2.4% and 0.2% in all TB patients. In sputum smear-negative TB suspects, a positive Xpert result is strongly indicative of culture confirmation; however, a negative result is insufficient to rule out active TB. Where clinical suspicion of pulmonary TB persists despite a negative Xpert result, local immunodiagnosis using T-SPOT on BAL may increase diagnostic accuracy.

Chest radiographic findings in patients with HIV/AIDS and pulmonary tuberculosis

The study describes the main chest radiographic changes in people living with HIV/AIDS and pulmonary tuberculosis, confirmed by sputum culture. This was a descriptive study involving a total of 42 sputum tests from 42 people living with HIV/AIDS and a clinical suspicion of pulmonary tuberculosis. All patients attended two referral hospitals in Recife-PE, Brazil, between August 2009 and January 2012. The most common isolated radiological change was parenchymal consolidation, encountered in six (14.3%) patients, followed by patterns of interstitial infiltrate, diffuse micronodular (miliary), and an association between interstitial infiltrate and parenchymal consolidation, each being encountered in five (11.9%) patients. No statistically significant difference was observed between the radiological findings and CD4 T-cell counts, p = 0.680.

A Diagnostic Accuracy Study of Xpert®MTB/RIF in HIV-Positive Patients with High Clinical Suspicion of Pulmonary Tuberculosis in Lima, Peru

BackgroundDiagnosis of pulmonary tuberculosis (TB) among human immunodeficiency virus (HIV) patients remains complex and demands easy to perform and accurate tests. Xpert®MTB/RIF (MTB/RIF) is a molecular TB diagnostic test which is rapid and convenient; the test requires minimal human resources and reports results within two hours. The majority of performance studies of MTB/RIF have been performed in high HIV burden settings, thus TB diagnostic studies among HIV patients in low HIV prevalence settings such as Peru are still needed.Methodology/Principal FindingsFrom April 2010 to May 2011, HIV-positive patients with high clinical suspicion of TB were enrolled from two tertiary hospitals in Lima, Peru. Detection of TB by MTB/RIF was compared to a composite reference standard Löwenstein-Jensen (LJ) and liquid culture. Detection of rifampicin resistance was compared to the LJ proportion method. We included 131 patients, the median CD4 cell count was 154.5 cells/mm3 and 45 (34.4%) had TB. For TB detection among HIV patients, sensitivity of MTB/RIF was 97.8% (95% CI 88.4–99.6) (44/45); specificity was 97.7% (95% CI 91.9–99.4) (84/86); the positive predictive value was 95.7% (95% CI 85.5–98.8) (44/46); and the negative predictive value, 98.8% (95% CI 93.6–99.8) (84/85). MTB/RIF detected 13/14 smear-negative TB cases, outperforming smear microscopy [97.8% (44/45) vs. 68.9% (31/45); p = 0.0002]. For rifampicin resistance detection, sensitivity of MTB/RIF was 100% (95% CI 61.0–100.0) (6/6); specificity was 91.0% (95% CI 76.4–96.9) (30/33); the positive predictive value was 66.7% (95% CI 35.4–87.9) (6/9); and the negative predictive value was 100% (95% CI 88.7 –100.0) (30/30).Conclusions/SignificanceIn HIV patients in our population with a high clinical suspicion of TB, MTB/RIF performed well for TB diagnosis and outperformed smear microscopy.

Validation of a Clinical-Radiographic Score to Assess the Probability of Pulmonary Tuberculosis in Suspect Patients with Negative Sputum Smears

BackgroundClinical suspects of pulmonary tuberculosis in which the sputum smears are negative for acid fast bacilli represent a diagnostic challenge in resource constrained settings. Our objective was to validate an existing clinical-radiographic score that assessed the probability of smear-negative pulmonary tuberculosis (SNPT) in high incidence settings in Peru.Methodology/Principal FindingsWe included in two referral hospitals in Lima patients with clinical suspicion of pulmonary tuberculosis and two or more negative sputum smears. Using a published but not externally validated score, patients were classified as having low, intermediate or high probability of pulmonary tuberculosis. The reference standard for the diagnosis of tuberculosis was a positive sputum culture in at least one of 2 liquid (MGIT or Middlebrook 7H9) and 1 solid (Ogawa) media. Prevalence of tuberculosis was calculated in each of the three probability groups.684 patients were included. 184 (27.8%) had a diagnosis of pulmonary tuberculosis. The score did not perform well in patients with a previous history of pulmonary tuberculosis. In patients without, the prevalence of tuberculosis was 5.1%, 31.7% and 72% in the low, intermediate and high probability group respectively. The area under de ROC curve was 0.76 (95% CI 0.72–0.80) and scores ≥6 had a positive LR of 10.9.Conclusions/SignificanceIn smear negative suspects without previous history of tuberculosis, the clinical-radiographic score can be used as a tool to assess the probability of pulmonary tuberculosis and to guide the decision to initiate or defer treatment or to requesting additional tests.

Comparative Evaluation of Nested PCR and Conventional Smear Methods for the Detection of Mycobacterium tuberculosis in Sputum Samples

With 1.8 million new cases each year, India carries 20% of the global burden of tuberculosis, a situation that is now further exacerbated with the emergence of drug resistance. The current diagnostic technique suggested by the Government of India's Revised National Tuberculosis Control Programme is Ziehl-Neelsen staining of a sputum smear. This technique is known to be inadequate. The aim of this study was to evaluate nested PCR (nPCR) in the detection of pulmonary tuberculosis in sputum samples in comparison with conventional smear findings, in an effort to improve detection rates from those obtained by the smear-alone approach. Patients attending a tertiary-care hospital (situated in a rural area of Vellore district) with clinical suspicion of pulmonary tuberculosis were prospectively recruited from mid-April 2009 to mid-December 2009 and investigated. The sputum samples were stained by Ziehl-Neelsen staining for smear examination. DNA extracted from concentrated sputum was tested by nPCR, targeting the IS6110 sequence in the Mycobacterium tuberculosis genome. Among 84 patients tested (median age 45.5 years), 80.95% were from the rural community and 19.05% were from the peri-urban community. Seventeen patients (20.24%; mid-p 95% CI 31.5, 52.4) tested positive by the smear examination and 35 (41.67%; mid-p 95% CI 12.7, 29.8) tested positive by nPCR. The difference in detection rates was statistically significant (chi(2) = 9.02; p = 0.002). The kappa coefficient between smear findings and nPCR findings was 0.47, which was a statistically significant agreement (Z = 4.91; p < 0.0001). This report describes the molecular detection of M. tuberculosis in patients' sputum samples tested by the nPCR format, using IS6110 as a target sequence. A high prevalence of pulmonary tuberculosis was identified by the nPCR assay, which was shown to have a significantly higher detection rate than conventional smear staining.