Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis

Comparison of 3 diagnostic methods for pulmonary tuberculosis in suspected patients with negative sputum smear or no sputum

STUDY DESIGN

To explore the diagnostic value of 3 methods for sputum smear-negative and non-sputum patients with suspected pulmonary tuberculosis (TB).

METHODS

This prospective study enrolled sputum smear-negative and non-sputum patients with suspected TB admitted to Jiangxi Chest Hospital between January 2020 and December 2022. The 3 methods were bronchoalveolar lavage fluid (BALF)-acid-fast bacillus (AFB) smear, GeneXpert MTB/RIF, and gene chip for Mycobacterium strain identification. The diagnostic performance of the 3 tests was evaluated with BALF Mycobacterium culture + BALF-AFB smear + GeneXpert MTB/RIF + Gene chip as the gold standard.

RESULTS

A total of 456 samples were collected from 114 patients with suspected TB. Twenty-four patients were diagnosed with TB. The combination of GeneXpert MTB/RIF and gene chip for Mycobacterium strain identification yielded the highest area under the receiver operating characteristics curve (AUC) of 0.953 and had sensitivity of 90.57%, specificity of 100%, positive predictive value (PPV) of 100%, negative predictive value (NPV) of 92.42%, accuracy of 95.61%. GeneXpert MTB/RIF achieved AUC of 0.906, sensitivity of 81.13%, specificity of 100%, PPV of 100%, NPV of 85.92%, accuracy of 91.23%. BALF-AFB smear had AUC of 0.519, sensitivity of 3.77%, specificity of 100%, PPV of 100%, NPV of 54.46%, and accuracy of 55.26%. The combination of GeneXpert MTB/RIF and gene chip for Mycobacterium strain identification yielded the highest κ of 0.911, while BALF-AFB smear had the lowest κ value of 0.040.

CONCLUSION

For TB in sputum smear-negative and non-sputum patients using BALF Mycobacterium culture + BALF-AFB smear + GeneXpert MTB/RIF + Gene chip as the gold standard, BALF-AFB smear showed low diagnostic performance, while, though GeneXpert MTB/RIF and gene chip had good diagnostic performance, combining GeneXpert MTB/RIF and gene chip improved the diagnostic value to a great extent.

Usefulness of bronchial washing fluid for detection of EGFR mutations in non-small cell lung cancer

INTRODUCTION

The implementation of bronchial washing fluid (BWF) as a diagnostic specimen may complement the low diagnostic yields of plasma in detecting EGFR mutation (mEGFR) in non-small cell lung cancer. However, the diagnostic value of BWF in detecting mEGFR has yet to be clarified.

MATERIALS AND METHODS

From March 2021 to August 2022, patients with histologically confirmed NSCLC with matched tumor tissue, BWF, and/or plasma samples were enrolled. Patients were classified into either initial diagnosis or rebiopsy groups. Diagnostic yields of mEGFR in BWF and plasma were evaluated using droplet digital polymerase chain reaction and compared to mEGFR in tumor tissue as standard.

RESULTS

The study included 123 patients (74.1 %) in the initial diagnosis and 43 patients (25.9 %) in the rebiopsy group. BWF showed higher sensitivity, specificity, and concordance rates than plasma in both the initial diagnosis (57.4 %, 96.4 %, and 74.0 % vs. 16.4 %, 96.2 %, and 53.1 %) and the rebiopsy group (87.9 %, 60.0 %, and 81.4 % vs. 25.0 %, 75.0 %, and 41.7 %). In the initial diagnosis group, mEGFR was detected in the BWF of 13 out of 16 patients, even in the absence of tumor cells in the tissue biopsy. In these cases, EGFR test results obtained from BWF showed concordance with EGFR test results from the tumor tissue obtained through repeated biopsy or surgery later. In the rebiopsy group, T790M was detected in 16 patients (37.2 %) by tissue biopsy. The combined use of tissue biopsy and BWF increased detection, confirming T790M in 22 patients (51.2 %).

DISCUSSION

The detection of mEGFR using BWF shows higher diagnostic yields than plasma for both initial diagnosis and rebiopsy. T790M was detected earlier in BWF than in tissue rebiopsy in some cases, providing patients with an early opportunity to access third-generation EGFR-TKIs. The complementary use of BWF with tumor tissue may improve precision in EGFR-mutated NSCLC treatment strategies.

Diagnostic value of bronchoscopy in sputum-negative pulmonary tuberculosis patients and its correlation with clinicoradiological features

CONTEXT:

Tuberculosis (TB) remains endemic in Saudi Arabia. Little local data have been reported on bronchoscopic evaluation of sputum-negative pulmonary TB patients, which poses a significant diagnostic and therapeutic challenge.

AIMS:

To determine the diagnostic value of bronchoscopy and bronchoalveolar lavage (BAL) and its correlation with clinical and radiological features in sputum-negative, culture-confirmed pulmonary TB patients.

METHODS:

We performed a retrospective analysis of patients with definite or probable pulmonary TB with overall negative (smear and/or polymerase chain reaction [PCR]) or scanty sputum that had undergone bronchoscopy with BAL over a period of 5 years. Patients’ symptoms, radiological features, lung lobe lavaged, BAL acid-fast bacilli (AFB) stain, Mycobacterium TB (MTB)-PCR, and mycobacterial cultures were analyzed. Mycobacterial cultures (either sputum or BAL) were used as a reference standard.

RESULTS:

Out of 154 patients, 49 (32%) were overall sputum negative and underwent a diagnostic bronchoscopy. Dry cough and fever were the most common symptoms. Uncontrolled diabetes mellitus was the most frequent comorbidity identified in 15 (31%) patients. Fifty-nine percent of the patients had diffuse lung infiltrates, with consolidation being the most common abnormality (41%), followed by cavitation (39%). Right upper lobe was the most frequent lung lobe lavaged (31%), while transbronchial lung biopsies (TBLB) were obtained in 21 (43%). BAL mycobacterial culture and MTB PCR were positive in 35 (71%) and 23 (47%) patients, respectively. Combined BAL MTB PCR and TBLB provided rapid diagnosis in 28 (57%) patients.

CONCLUSIONS:

An overall diagnostic yield of 90% was achieved with combined use of BAL MTB PCR, culture, and histopathology. Upper lobe lavage and presence of cavities on chest imaging had a higher diagnostic yield.

Harnessing Big Data to Optimize an Algorithm for Rapid Diagnosis of Pulmonary Tuberculosis in a Real-World Setting

Background

The prompt diagnosis of pulmonary tuberculosis (PTB) remains a challenge in clinical practice. The present study aimed to optimize an algorithm for rapid diagnosis of PTB in a real-world setting.

Methods

28,171 adult inpatients suspected of having PTB in China were retrospectively analyzed. Bronchoalveolar lavage fluid (BALF) and/or sputum were used for acid-fast bacilli (AFB) smear, Xpert MTB/RIF (Xpert), and culture. A positive mycobacterial culture was used as the reference standard. Peripheral blood mononuclear cells (PBMC) were used for T-SPOT.TB. We analyzed specimen types' effect on these assays' performance, determined the number of smears for diagnosing PTB, and evaluated the ability of these assays performed alone, or in combination, to diagnose PTB and nontuberculous mycobacteria (NTM) infections.

Results

Sputum and BALF showed moderate to substantial consistency when they were used for AFB smear or Xpert, with a higher positive detection rate by BALF. 3-4 smears had a higher sensitivity than 1-2 smears. Moreover, simultaneous combination of AFB and Xpert correctly identified 44/51 of AFB⁺/Xpert⁺ and 6/7 of AFB⁺/Xpert^- cases as PTB and NTM, respectively. Lastly, when combined with AFB/Xpert sequentially, T-SPOT showed limited roles in patients that were either AFB⁺ or Xpert⁺. However, T-SPOT^MDC (manufacturer-defined cut-off) showed a high negative predicative value (99.1%) and suboptimal sensitivity (74.4%), and TBAg/PHA (ratio of Mycobacterium tuberculosis-specific antigens to phytohaemagglutinin spot-forming cells, which is a modified method calculating T-SPOT.TB assay results) ≥0.3 demonstrated a high specificity (95.7%) and a relatively low sensitivity (16.3%) in AFB^-/Xpert^- patients.

Conclusions

Concurrently performing AFB smear (at least 3 smears) and Xpert on sputum and/or BALF could aid in rapid diagnosis of PTB and NTM infections in a real-world high-burden setting. If available, BALF is preferred for both AFB smear and Xpert. Expanding this algorithm, PBMC T-SPOT^MDC and TBAg/PHA ratios have a supplementary role for PTB diagnosis in AFB^-/Xpert^- patients (moderately ruling out PTB and ruling in PTB, respectively). Our findings may also inform policy makers' decisions regarding prevention and control of TB in a high burden setting.

Surgical management of empyema thoracis - experience of a decade in a tertiary care centre in India

Introduction and purpose

Empyema thoracis (ET) is defined as the accumulation of pus in the pleural cavity. Early stages of ET are treated medically and the late stages surgically. Decortication, thoracoplasty, window procedure (Eloesser flap procedure) and rib resections are the open surgical procedures executed. There are no strict guidelines available in developing nations to guide surgical decision-making, as to which procedure is to be followed.

Methods

Details of all adult patients treated surgically for ET, between the years 2009 and 2019, and maintained in a live database in our institute, were retrieved and analysed. Medically managed patients were excluded.

Results

There were 437 patients in the study. The average age was 38 years. There was right side preponderance with a male:female ratio of 5:1. Tuberculosis was the commonest aetiology identified in 248 (57%) patients and diabetes was the commonest co-morbidity present in 97 (22%) patients. There was a higher incidence of a window procedure (WP) in tubercular patients 145 (59%). Only 26 (14%) of the non-tubercular patients underwent a WP. Post-operative complications were persistent air leak in 12 (6%) patients and premature closure of a window in 7 (4%) patients. There were 4 (0.9%) post-operative mortalities.

Conclusion

Surgical management of late stages of ET provides good results with minimal morbidity and mortality. In developing nations like India, the high incidence of tuberculosis and late presentations make the surgical management difficult and the strategies different from those in developed nations. No clear guidelines exist for the surgical management of ET in developing nations. There is a need for a consensus on the surgical management of empyema in such countries.

Diagnostic value of bronchoalveolar lavage and bronchial washing in sputum-scarce or smear-negative cases with suspected pulmonary tuberculosis: a randomized study

OBJECTIVES

Bronchoalveolar lavage (BAL) and bronchial washing (BW) are two major methods used to obtain high-quality respiratory specimens from patients with suspected pulmonary tuberculosis (TB) but a sputum-scarce or smear-negative status. We aimed to compare the value of BAL and BW in the diagnosis of TB in such patients.

METHODS

We enrolled patients with suspected pulmonary TB but with a sputum-scarce or smear-negative status who were referred for bronchoscopy between October 2013 and January 2016. Participants were randomized into the BAL and BW groups for evaluation. The primary outcome was the diagnostic yield for TB detection. Secondary outcomes included culture positivity, positivity of nucleic acid amplification tests (NAATs) for Mycobacterium tuberculosis and procedure-related complications.

RESULTS

A total of 94 patients were assessed and 91 (43 in the BAL group, 48 in the BW group) were analysed. Twenty-one patients (48.8%) in the BAL group and 30 (62.5%) in the BW group had a final diagnosis of pulmonary TB. The detection rate of M. tuberculosis by culture or NAAT was significantly higher in BAL specimens than in BW specimens (85.7% vs 50.0%, p 0.009). The procedure-related complications were hypoxic events, 2/43 (4.7%) in the BAL group and 5/48 (10.4%) in the BW group; and post-bronchoscopic fever, 3/43 (7.0%) in the BAL group and 4/48 (8.3%) in the BW group.

DISCUSSION

As long as it is tolerable, BAL rather than BW, should be used to obtain specimens for the diagnosis of pulmonary TB in sputum-scarce or smear-negative cases.

A Clinical TB Detection Method Based on Molecular Typing Technique with Quality Control

The gold standard for diagnosing pulmonary Mycobacterium tuberculosis (TB) is the detection of tubercle bacillus in patient sputum samples. However, current methods either require long waiting times to culture the bacteria or have a risk of getting false-positive results due to cross-contamination. In this study, a method to detect tubercle bacillus based on the molecular typing technique is presented. This method can detect genetic units, variable number of tandem repeat (VNTR), which are the characteristic of tuberculosis (TB), and performs quality control using a mathematical model, ensuring the reliability of the results. Compared to other methods, the proposed method was able to process and diagnose a large volume of samples in a run time of six hours, with high sensitivity and specificity. Our method is also in the pipeline for implementation in clinical testing. Reliable and confirmed results are stored into a database, and these data are used to further refine the model. As the volume of data processed from reliable samples increases, the diagnostic power of the model improves. In addition to improving the quality control scheme, the collected data can be also used to support other TB research, such as that regarding the evolution of the tubercle bacillus.

Role of Xpert MTB/RIF in Bronchoalveolar lavage fluid of sputum-scarce, suspected Pulmonary TB patients

Setting

A prospective observational study conducted in Medical college hospital, in a high-TB- prevalence region of northern Telangana, India.

Objective

To know the diagnostic role of Xpert MTB/RIF assay in bronchoalveolar lavage fluid (BALF) in sputum-scarce, suspected pulmonary tuberculosis (PTB) patients.

Design

Study period was between October 2014 and March 2017. Suspected pulmonary tuberculosis patients aged 15 years or more, who were sputum-scarce and conforming to the inclusion criteria were submitted to bronchoscopy. BALF thus obtained was submitted to smear for acid fast bacilli (AFB) and Xpert MTB/RIF assay as index tests along with culture for Mycobacterium tuberculosis complex (MTBC). Culture for M. tuberculosis complex was considered as gold standard for the diagnosis of PTB. The sensitivity, specificity and predictive values were calculated for smear AFB and Xpert MTB/RIF assay.

Results

56 of the 81 patients were included and evaluated in the final analysis. In 10 of these 56 patients PTB was confirmed by culture positivity. The sensitivity and specificity of Xpert MTB/RIF assay was 90% (9/10,95%CI 59.6- 98.2) and 52.2% (24/46, 95%CI 38. 1-65.9) respectively and that of the smear AFB was 60% (6/10, 95%CI 31.2–83.1) and 67.4% (31/46, 95%CI 53.0–79.1). All the patients considered ‘probable’ PTB (pending culture results), were administered antituberculous treatment and showed complete clinicoradiological improvement on follow up. Three of the 31 Xpert MTB/RIF positive patients were detected as resistance to rifampicin (RR).

Conclusions

Xpert MTB/RIF assay of BALF in the study cohort provides rapid diagnosis of Mycobacterium tuberculosis, and detection of rifampicin resistance at the very outset, aiding in selection of appropriate ATT regimen. In this context, it can be recommended as the first line investigation. Xpert MTB/RIF assay aided by HRCT Chest and suggestive clinical presentation may be helpful in early institution of ATT especially in smear negative, culture negative cases.

Polymerase chain reaction test in induced sputum of patients with pulmonary tuberculosis

INTRODUCTION

Induced sputum (IS) is an alternative method of obtaining sputum, but IS smears are frequently negative. Culture is more time consuming in its results, and less useful to guide the diagnosis. Polymerase chain reaction (PCR) is the most common methodology for rapid diagnosis of tuberculosis (TB), and few studies evaluated its role in IS samples.

OBJECTIVES

The objective of this study is to determine the diagnostic yield of PCR for TB compared with culture in IS samples.

MATERIALS AND METHODS

Prospective study. Inpatients and outpatients of >18 years with respiratory symptoms suggestive of PTB were invited to participate. The subjects were interviewed using a standardized questionnaire, and collected IS. Three samples were obtained for AFB smear and culture. A fourth sample was obtained for PCR test.

RESULTS

A total of 116 IS samples were evaluated. The sensitivity, specificity, positive predictive value and negative predictive values of PCR were 95.2%, 48.4%, 29.0% and 97.9%, respectively. The area under the receiver operating characteristic curve was .72 for the PCR test (P < .0001).

CONCLUSIONS

Although the PCR specificity could be underestimated, if we consider PCR to be more sensitive than the culture method used, we believed that these PCR-positive tests mean false positives. The results of PCR should always be interpreted carefully in conjunction with clinical information.

Antemortem diagnosis of Mycobacterium bovis infection in free-ranging African lions (Panthera leo) and implications for transmission

Diagnosis of tuberculosis in wildlife often relies on postmortem samples because of logistical challenges and lack of field-friendly techniques for live animal testing. Confirmation of infection through detection of infectious organisms is essential for studying the pathogenesis and epidemiology of disease. We describe the application of a technique to obtain respiratory samples from free-ranging living lions to facilitate detection of viable Mycobacterium bovis under field conditions. We identified M. bovis by mycobacterial culture and PCR in tracheobronchial lavage samples from 8/134 (6.0%) lions tested in Kruger National Park, South Africa. This confirms the respiratory shedding of viable M. bovis in living lions. The implications of these results are that infected lions have the potential to transmit this disease and serve as maintenance hosts.

The effectiveness of real-time PCR assay, compared with microbiologic results for the diagnosis of pulmonary tuberculosis

Background

The incidence of tuberculosis (TB) in Korea is relatively high compared to the other Organisation for Economic Co-operation and Development (OECD) countries, with a prevalence of 71 per 100,000 in 2012, although the incidence is declining. Real-time polymerase chain reaction (PCR) has been introduced for the rapid diagnosis of TB. Recently, its advantage lies in higher sensitivity and specificity for the diagnosis of TB. This study evaluated the clinical accuracy of real-time PCR using respiratory specimens in a clinical setting.

Methods

Real-time PCR assays using sputum specimens and/or bronchoscopic aspirates from 2,877 subjects were reviewed retrospectively; 2,859 subjects were enrolled. The diagnosis of TB was determined by positive microbiology, pathological findings of TB in the lung and pleura, or clinical suspicion of active TB following anti-TB medication for more than 6 months with a favorable response.

Results

Sensitivity, specificity, and accuracy were 44%, 99%, and 86% from sputum, and 65%, 97%, and 87% from bronchoscopic aspirates, respectively. For overall respiratory specimens, sensitivity was 59%, specificity was 98%, and accuracy increased to 89%.

Conclusion

Positivity in real-time PCR using any respiratory specimens suggests the possibility of active TB in clinically suspected cases, guiding to start anti-TB medication. Real-time PCR from selective bronchoscopic aspirates enhances the diagnostic yield much more when added to sputum examination.

Retrospective observational study of diagnostic accuracy of the Xpert® MTB/RIF assay on fiberoptic bronchoscopy sampling for early diagnosis of smear-negative or sputum-scarce patients with suspected tuberculosis

Background

Fiberoptic bronchoscopy (FOB) is a useful diagnosis tool in low-burden countries for patients with suspected pulmonary tuberculosis (TB) who are smear-negative or sputum-scarce. This study sought to determine the accuracy of the Xpert® MTB/RIF (XP) assay using FOB samples.

Methods

We retrospectively reviewed clinical, radiological, and microbiological characteristics of 175 TB-suspected patients requiring diagnostic FOB (bronchial aspirate or bronchoalveolar lavage) with XP assay. Polymerase chain reaction (PCR) and smear microscopy (SM) performances were first compared to culture, then to the final diagnosis, established based on clinical or radiological evolution when cultures were negative.

Results

Of the total 162 included patients, 30 (18.5%) had a final diagnosis of pulmonary TB, with positive cultures reported in 23. As compared to culture, sensitivity and specificity values were 80.0% and 98.6% for the XP assay, and 25.0% and 95.8% for SM, respectively. As compared to final diagnosis, the corresponding performance values were 60.0% and 100.0% for the XP assay, and 16.7% and 95.5% for SM, respectively. The sensitivity of the XP assay was significantly higher than that of SM in both cases (p = 0.003 and p = 0.001). Concerning the final diagnosis, both XP assay and culture sensitivities were similar (60% vs. 66.7%). PCR assay enabled pulmonary TB to be diagnosed earlier in 13 more cases, compared to SM.

Conclusion

Our study has confirmed the clinical benefits provided by XP assay compared to SM for the early diagnosis of suspected pulmonary TB cases requiring FOB, on per procedure samples, especially in a low TB-burden country.

A rapid, real-time quantitative polymerase chain reaction test for the identification of pathogens in bronchoalveolar lavage samples

BACKGROUND

Standard bacteriologic culture techniques offer results within 2 days to 3 days, precluding a focused and timely antibiotic therapy in ventilated trauma patients. Our laboratory developed a real-time quantitative polymerase chain reaction (qPCR) test that can detect 25 different bacteria and fungi and methicillin resistance and offers results within 3 hours. The objective of this study was to compare the qPCR method to standard culture techniques.

METHODS

This was a prospective observational cohort study at a Level I trauma center from 2009 to 2012. Adult trauma patients on ventilation, receiving at least one bronchoalveolar lavage (BAL) with culture results were eligible for inclusion. DNA was isolated from the BAL samples and analyzed in 96-well plates using qPCR. Student's t tests were used to examine differences in mean qPCR cycle counts. Sensitivities, specificities, negative predictive values, and positive predictive values were calculated for the qPCR primer sets.

RESULTS

There were 28 BALs in the study. The qPCR method detected a total of 165 organisms, and culture methods found 54. The qPCR test had an overall sensitivity of 85%, specificity of 74%, negative predictive value of 98%, and positive predictive value of 27%. Those organisms that were only identified through qPCR had significantly less DNA than those identified through both qPCR and quantitative culture (28.8 vs. 23.3, p < 0.001). Concurrent antibiotic therapy was found to decrease the qPCR specificity in some primer sets, and methicillin resistance was only found in BAL samples that were concurrent with antibiotics.

CONCLUSION

The qPCR method shows promising initial diagnostic value. Many of the organisms not identified by quantitative culture had late cycle calls, suggesting that they might have been in quantities too low to result in culture identification. Once refined, our qPCR method has the potential to identify pathogens faster and earlier than standard quantitative culture methods, allowing for targeted antibiotic therapy within 3 hours.

LEVEL OF EVIDENCE

Diagnostic test, level II.

Clinical Utility of CT-Based Bronchial Aspirate TB-PCR for the Rapid Diagnosis of Pleural Tuberculosis

Background

Thoracoscopic pleural biopsy is often required for rapid and confirmative diagnosis in patients with suspected pleural tuberculosis (PL-TB). However, this method is more invasive and costly than its alternatives. Therefore, we evaluated the clinical utility of the chest computed tomography (CT)-based bronchial aspirate (BA) TB-polymerase chain reaction (PCR) test in such patients.

Methods

Bronchoscopic evaluation was performed in 54 patients with presumptive PL-TB through diagnostic thoracentesis but without a positive result of sputum acid-fast bacilli (AFB) smear, pleural fluid AFB smear, or pleural fluid TB-PCR test. Diagnostic yields of BA were evaluated according to the characteristics of parenchymal lesions on chest CT.

Results

Chest radiograph and CT revealed parenchymal lesions in 25 (46%) and 40 (74%) of 54 patients, respectively. In cases with an absence of parenchymal lesions on chest CT, the bronchoscopic approach had no diagnostic benefit. BA TB-PCR test was positive in 21 out of 22 (95%) patients with early-positive results. Among BA results from 20 (37%) patients with patchy consolidative CT findings, eight (40%) were AFB smear-positive, 18 (90%) were TB-PCR-positive, and 19 (95%) were culture-positive.

Conclusion

The BA TB-PCR test seems to be a satisfactory diagnostic modality in patients with suspected PL-TB and patchy consolidative CT findings. For rapid and confirmative diagnosis in these patients, the bronchoscopic approach with TB-PCR may be preferable to the thoracoscopy.

Predictive factors for tuberculosis in patients with a TB-PCR-negative bronchial aspirate

PURPOSE

Pulmonary tuberculosis (PTB), with a tuberculosis (TB)-polymerase chain reaction (PCR)-negative bronchial aspirate (BA), but a positive culture result is often encountered in clinical practice. However, limited data are available concerning clinical judgment in patients with suspected PTB and a TB-PCR-negative BA pending culture results. The present study aimed to identify predictors for PTB in patients with a TB-PCR-negative BA.

METHODS

A retrospective study was conducted on patients who had undergone a bronchoscopy because of suspected PTB. Clinical, laboratory, and computed tomography (CT) findings were investigated in PTB patients with TB-PCR-negative but positive culture BA results, and non-PTB patients with a radiographic lesion comparable to the former.

RESULTS

Of 250 patients screened, 31 (12 %) were diagnosed with PTB by positive culture results only. Of these 31 patients, 30 (97 %) had a lesion within one-third of the hemithorax as determined by chest radiography. In the final analysis of 30 PTB and 65 non-PTB patients with comparable radiographic lesions, a positive QuantiFERON-TB Gold In-Tube (QFT) result was independently associated with an increased risk of a positive TB culture. CT findings of consolidation were a negative predictor for PTB. Patients with a negative QFT result and consolidation had a negative predictive value of 95 % for PTB, while patients with a positive QFT result and nodular CT abnormalities without consolidation had a positive predictive value of 86 % for PTB.

CONCLUSION

The simple combination of CT findings of consolidation and QFT test results may help clinicians to refine decision-making in patients with a TB-PCR-negative BA.

Investigation of endobronchial tuberculosis diagnoses in 22 cases

BACKGROUND

Endobronchial tuberculosis (EBTB) is a special form of pulmonary tuberculosis. In spite of much progress in the diagnosis of this disease in past years, delayed or mistaken diagnosis is still commonly seen.

OBJECTIVE

The aim of this study is to try to find out some useful clues for the diagnosis of EBTB, especially the early diagnosis.

METHODS

The medical records of patients with EBTB were analyzed retrospectively.

RESULTS

The male-to-female ratio was 1:2.2 out of 22 patients. Patients aged below 60-years-old constituted 72.7% of the cases. 22.7% of these patients were smokers. The male-to-female ratio of smokers was 4:1. 68.2% of these patients tested all showed negative result for the HIV test. The frequent complaints were cough, sputum, shortness of breath and fever, and antibiotic treatments were usually inefficacious. Multiple lobes lesion, exudative shadow and atelectasis were the frequent radiological findings. Acid-fast bacilli staining for sputum smear was positive in only 13.6% of these patients. Tuberculin skin test was positive in 59.1% of these patients. Granular lesion was the most common bronchoscopic appearance in these patients. Histological changes showed distinctive tuberculose lesion in 72.2% of 18 patients undergoing bronchoscopic biopsy.

CONCLUSION

The diagnosis of EBTB is easily delayed or mistaken because of nonspecific clinical manifestations and the low incidence of positive acid-fast bacilli staining. A high index of awareness of this disease is required for diagnosis. Bronchoscopy should be performed as soon as possible in suspected patients, especially when patients present positive tuberculin skin test or no response to antibiotic treatments.

Combination of adenosine deaminase activity and polymerase chain reaction in bronchoalveolar lavage fluid in the diagnosis of smear-negative active pulmonary tuberculosis

BACKGROUND

Some studies have assessed the diagnostic value of adenosine deaminase (ADA) activity in bronchoalveolar lavage fluid (BALF) in the diagnosis of pulmonary tuberculosis (TB). However, a conclusion has not been reached due to the limited number of patients with various pulmonary diseases used as comparators. The objective of this study was to evaluate the efficacy of BALF ADA activity and TB PCR assay for diagnosing pulmonary TB.

METHODS

BAL samples from 424 patients with acid-fast bacillus-negative sputum smears who underwent bronchoscopy for diagnostic evaluations of pulmonary diseases, were prospectively analyzed for ADA activity and TB PCR.

RESULTS

The median ADA activity of TB cases was significantly different from that of patients with solid tumor without endobronchial obstruction (p<0.001), inactive TB (p=0.04), and other (p=0.038), while this was not the case for the other pulmonary diseases. A cutoff BALF ADA activity of ≥3 U/l provided a sensitivity of 58.7% and specificity of 81.8% to differentiate TB from solid tumor without endobronchial obstruction. The sensitivity of TB PCR in BALF was 28.1% with a specificity of 99.0%. The area under the receiver operating characteristic (ROC) curve to differentiate TB from solid tumor without endobronchial obstruction was significantly higher for the combination of ADA activity ≥3 U/l and TB PCR (0.77) than for ADA activity ≥3 U/l alone (0.70, p<0.001) or for TB PCR alone (0.64, p<0.001). The sensitivity of the combination of ADA activity ≥3 U/l and TB PCR was 72.7% and the specificity was 81.8%. In TB cases, a greater radiographic extent of disease was associated with a higher median ADA activity (p=0.017).

CONCLUSIONS

BALF ADA had limited value in differentiating pulmonary TB from some other pulmonary diseases. To differentiate TB from solid tumor without endobronchial obstruction, a combination of BALF ADA and TB PCR had marked additive diagnostic value.

Clinical value of whole-blood interferon-gamma assay in patients with suspected pulmonary tuberculosis and AFB smear- and polymerase chain reaction-negative bronchial aspirates

Combining a polymerase chain reaction (PCR) test with bronchoscopy is frequently performed to allow a rapid diagnosis of smear-negative pulmonary tuberculosis (PTB). However, limited data are available concerning clinical judgment in patients with suspected PTB and AFB smear- and PCR-negative bronchial aspirates (BA). The present study evaluated the usefulness of whole-blood QuantiFERON-TB Gold In-Tube (QFT) testing in these patients. Of 166 patients with suspected PTB who had undergone bronchoscopy because of smear-negative sputum or inadequate sputum production, 93 (56%) were diagnosed with culture-positive PTB. Seventy-four patients were either AFB smear- or PCR-positive. In the 75 patients whose BA AFB smear and PCR results were both negative, 19 were finally diagnosed with PTB by culture. The QFT test had a negative predictive value of 91% for PTB. The QFT test may be useful for excluding PTB in patients with suspected PTB whose BA AFB smear and PCR results are both negative.

The diagnostic accuracy of tuberculosis real-time polymerase chain reaction analysis of computed tomography-guided bronchial wash samples

We evaluated the diagnostic accuracy of real-time polymerase chain reaction (RT-PCR) analysis of bronchoscopic wash specimens obtained using computed tomography (CT) guidance for diagnosis of pulmonary tuberculosis (TB) patients who were unable to produce sputum samples or were sputum smear-negative. Data from patients who had lesions likely to be pulmonary TB on CT images were analyzed retrospectively. Twenty-seven patients (23.1%) were diagnosed with definite pulmonary TB, and 72 patients (61.5%) were classified as not having TB. The sensitivity, specificity, positive predictive value, and negative predictive value of RT-PCR were 0.78 (95% CI, 0.57-0.91), 0.93 (95% CI, 0.84-0.97), 0.81 (95% CI, 0.60-0.93), and 0.92 (95% CI, 0.82-0.97), respectively. We concluded that most of the sputum-smear negative TB cases could be diagnosed microbiologically or ruled out rapidly and accurately by RT-PCR analysis of bronchial wash fluid.

Endobronchial tuberculosis: an overview

Endobronchial tuberculosis (EBTB), of which the incidence has been increasing in recent years, is a special type of pulmonary tuberculosis. The endobronchial tuberculose focuses often injure the tracheobronchial wall and lead to tracheobronchial stenosis. The tracheobronchial stenosis may cause intractable tuberculosis and make patients become chronic infection sources of tuberculosis, or may even cause pulmonary complications and result in death. The etiological confirmation of Mycobacterium tuberculosis is most substantial for diagnosis. However, because the positive rate of acid-fast bacillus staining for sputum smears is low and the clinical and radiological findings are usually nondistinctive, the diagnosis of EBTB is often mistaken and delayed. For early diagnosis, a high index of awareness of this disease is required and the bronchoscopy should be performed as soon as possible in suspected patients. The eradication of Mycobacterium tuberculosis and the prevention of tracheobronchial stenosis are two most substantial treatment goals. To get treatment goals, the diagnosis must be established early and aggressive treatments must be performed before the disease progresses too far.

Comparison of acid-fast stain and culture for Mycobacterium tuberculosis in pre- and post-bronchoscopy sputum and bronchoalveolar lavage in HIV-infected patients with atypical chest X-ray in Ethiopia

BACKGROUND:

Smear-negative tuberculosis occurs more frequently in human immunodeficiency virus (HIV)-infected patients than in non-HIV-infected patients. Besides, there are substantial numbers of patients who cannot produce sputum, making the diagnosis of pulmonary tuberculosis (PTB) difficult.

AIMS:

To evaluate the relative yield of pre- and post-bronchoscopy sputum and bronchoalveolar lavage (BAL) in ‘sputum smear’-negative, HIV-positive patients.

SETTINGS:

A tertiary care referral hospital in Addis Ababa.

MATERIALS AND METHODS:

Acid-fast stain (AFS) using the concentration technique was done on 85 pre-bronchoscopy sputum and 120 BAL samples. Direct AFS was done on all BAL and 117 post-bronchoscopy sputum samples. Culture for Mycobacterium tuberculosis (MTB) was done for all sputa and BAL.

RESULTS:

MTB was isolated from 26 (21.7%), 23 (19.7%) and 13 (15.3%) of BAL, post- and pre-bronchoscopy sputum cultures respectively. AFS on pre-bronchoscopy sputum using concentration technique and direct AFS on BAL together detected 11 (41%) of the 27 culture-positive cases. In patients who could produce sputum, the sensitivity of pre-bronchoscopy sputum culture (13/85, 15.3%) was comparable to BAL (12/85, 14%) and post-bronchoscopy sputum (12/85, 14%). In patients who could not produce sputum, however, both BAL (12/35, 40%) and post-bronchoscopy sputum (12/32, 31.4%) detected significantly more patients than those who could produce sputum (P=0.002, P=0.028 respectively).

CONCLUSION:

In HIV-infected patients, AFS by concentration method on pre-bronchoscopy sputum and direct AFS on BAL in patients who cannot produce sputum are the preferred methods of making a rapid diagnosis. BAL culture seems to add little value in patients who can produce sputum; therefore, bronchoscopy should be deferred under such circumstances.

Endobronchial ultrasound increases the diagnostic yields of polymerase chain reaction and smear for pulmonary tuberculosis

OBJECTIVES

Our objective was to determine the contribution of endobronchial ultrasound in the diagnostic yields of acid-fast bacillus smear, nucleic acid amplification tests, and culture in bronchoalveolar lavage fluid for pulmonary tuberculosis.

METHODS

During a 1-year interval, 99 patients who had initial sputum-negative acid-fast bacillus smears or no sputum but were later proven to have a positive culture for Mycobacterium tuberculosis in their sputum or bronchoalveolar lavage fluid were retrospectively studied. Among them, 56 patients underwent bronchoscopy with endobronchial ultrasound (EBUS group) and 43 patients received conventional bronchoscopy for bronchoalveolar lavage (non-EBUS group).

RESULTS

The diagnostic yields of the nucleic acid amplification tests (89.3%, 50/56; P = .006), acid-fast bacillus smear (30.4%, 17/56; P = .013), and M tuberculosis culture in bronchoalveolar lavage fluid (67.9%, 38/56; P = .041) were significantly higher in the EBUS group of patients. The results of those who underwent conventional bronchoscopy were 65.1% (28/43), 9.3% (4/43), and 46.5% (20/43), respectively. Combining bronchoalveolar lavage fluid smear and nucleic acid amplification tests, we made a rapid diagnosis of pulmonary tuberculosis in 51 (91.1%) of the 56 EBUS patients and 29 (67.4%; P = .004) of the 43 non-EBUS patients.

CONCLUSIONS

The introduction of endobronchial ultrasound increases the diagnostic yield of the nucleic acid amplification tests, acid-fast bacillus smear, and M tuberculosis culture from bronchioalveolar lavage fluid in patients with pulmonary tuberculosis who have negative sputum smear or no sputum production.

Pulmonary tuberculosis and drug resistance in Dhaka central jail, the largest prison in Bangladesh

Background

There are limited data on TB among prison inmates in Bangladesh. The aim of the study was to determine the prevalence of pulmonary tuberculosis (TB), its drug resistance and risk factors in Dhaka Central Jail, the largest prison in Bangladesh.

Methods

Cross sectional survey with, active screening of a total number of 11,001 inmates over a period of 2 years. Sputum samples from TB suspects were taken for acid- fast bacilli (AFB) microscopy, culture and drug susceptibility testing.

Results

Among 1,781 TB suspects 245 (13.8%) were positive for AFB on microscopy and/or culture. The prevalence rate of sputum- positive pulmonary TB was 2,227/100,000. Fifty three cases (21.6% of 245 cases) were AFB- negative on microscopy but were found positive on culture. Resistance to isoniazid, rifampicin, streptomycin and ethambutol was 11.4%, 0.8%, 22.4% and 6.5% respectively. No multidrug resistance was observed. The main risk factors of TB in prison were exposure to TB patients (adjusted odds ratio 3.16, 95% CI 2.36–4.21), previous imprisonment (1.86, 1.38–2.50), longer duration of stay in prison (17.5 months for TB cases; 1.004, 1.001–1.006) and low body mass index which is less than 18.5 kg/m² (5.37, 4.02–7.16).

Conclusions

The study results revealed a very high prevalence of TB in the prison population in Dhaka Central Jail. Entry examinations and active symptom screening among inmates are important to control TB transmission inside the prison. Identifying undiagnosed smear-negative TB cases remains a challenge to combat this deadly disease in this difficult setting.

The value of fiberoptic bronchoscopy in culture-positive pulmonary tuberculosis patients whose pre-bronchoscopic sputum specimens were negative both for smear and PCR analyses

OBJECTIVE

This study assessed the diagnostic rate of pulmonary tuberculosis (PTB) using fiberoptic bronchoscopy (FBS) in patients with suspected PTB, and negative pre-bronchoscopy smear and polymerase-chain reaction (PCR) in sputum.

PATIENTS AND METHODS

We retrospectively reviewed 201 culture-positive PTB patients that underwent FBS because both smear and PCR results in sputum were negative. The positive rates of smear for acid fast bacilli, PCR for Mycobacterium tuberculosis, the presence of granuloma in transbronchial biopsy (TBB), and culture of M. tuberculosis were analyzed. In addition, the radiographic features, contribution of FBS to rapid and/or definitive diagnosis of PTB, and drug susceptibility results of M. tuberculosis were also reviewed.

RESULTS

There were 136 males and 102 patients under the age of 40 years; non-cavitary (156 cases) and minimal disease (119 cases) on radiographs predominated. The positive rates of FBS were: 44% (smear), 62% (PCR), 61% (TBB), and 87% (culture). These rates increased in smear and PCR examinations when taken from wider spread shadows on radiographs. The combination of the various bronchoscopy samples increased the diagnostic rate to 92% when all examinations were combined. Positive culture results depended on FBS procedures in 80 cases. Twenty-one cases showed resistance to at least one of the major anti-tuberculous agents.

CONCLUSION

This analysis revealed high positive rates of PTB from bronchoscopy samples, providing rapid and definitive ability for PTB diagnosis, and details of drug susceptibility. Therefore, FBS is an important diagnostic procedure in patients with suspected PTB whose sputum specimens were negative both for smear and PCR analyses.

Transitional Change in the Clinical Features of Pulmonary Tuberculosis

BACKGROUND

An aging population, increased use of immunosuppressive therapy and an increase in patients with risk factors for tuberculosis have induced changes in the clinical features of pulmonary tuberculosis in Japan.

OBJECTIVE

To investigate transitional changes in the clinical features of recent patients with pulmonary tuberculosis.

METHODS

This study analyzed 820 patients with pulmonary tuberculosis who were culture positive for Mycobacterium tuberculosis in the Kawasaki Medical School Hospital and ten associated community hospitals between January 1986 and December 2005 (406 patients between January 1986 and December 1995 and 414 patients between January 1996 and December 2005).

RESULTS

The characteristic clinical features of the latter period were as follows: (1) an increase in the percentages of patients with both malignant diseases and collagen vascular diseases, (2) a decrease in the proportion of patients with obvious clinical symptoms, (3) an increase in the number of microbiologically smear-positive patients, (4) an increase in the percentages of patients with atypical radiological findings, (5) no change in the incidence of multidrug-resistant M. tuberculosis and (6) no change in the rate of the effect of treatment or prognosis.

CONCLUSIONS

The findings of an increase in atypical features may be related to the increase in immunocompromised patients and should therefore be investigated further. Performance of acid-fast bacillus examination is extremely important because a good prognosis can be achieved if an accurate diagnosis is established as soon as possible and the resistance of M. tuberculosis to antituberculous drugs has not progressed.

Primary nasolacrymal tuberculosis diagnosed after dacryocytorhinostomy

Although tuberculosis (TB) is common and well recognized in many countries, unusual presentations of the disease sometimes raise difficulties in differential diagnosis. Primary tuberculosis of the lacrimal sac and the nasolacrimal duct is an extremely rare presentation of extra-pulmonary tuberculosis. Dacryocystorhinostomy alone is not sufficient for the treatment of these patients and an anti-tuberculous therapy has to be added. Here we present a patient with primary tuberculosis, which is limited to the inferior meatus and filled the entire lacrimal sac on the left side. The patient underwent endoscopic dacryocystorhinostomy due to obstruction of the nasolacrimal duct and culture of the granulation tissue, taken from the lacrimal sac revealed mycobacterial tuberculosis. The patient was improved with anti-tuberculous therapy that was added to the surgery. Primary tuberculosis is a rare granulomatous disease of the nasolacrimal system, which should be considered in the differential diagnosis to plan the effective treatment.

Rapid diagnosis of smear-negative tuberculosis by bronchoalveolar lavage enzyme-linked immunospot

RATIONALE

In a large proportion of patients with active pulmonary tuberculosis (pTB), acid-fast bacilli smear results for sputum and bronchial secretions are negative. Detectable growth of Mycobacterium tuberculosis (MTB) in cultures takes several weeks and MTB-specific DNA amplification results on sputum and bronchial secretions are variable in these patients.

OBJECTIVE

We investigated whether a rapid diagnosis of pTB can be established by enumeration of MTB-specific mononuclear cells from bronchoalveolar lavage (BAL) fluid in routine clinical practice.

METHODS

Patients presenting to a tertiary hospital with medical histories and pulmonary infiltrates compatible with tuberculosis, and negative acid-fast bacilli smear results (three) from sputum, were prospectively enrolled in this study. An MTB-specific enzyme-linked immunospot assay (ELISPOT [T-SPOT.TB; Oxford Immunotec, Abingdon, UK]) with early antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) peptides was performed on peripheral blood mononuclear cells (PBMCs) and mononuclear cells from the BAL fluid (BALMCs).

MEASUREMENTS AND MAIN RESULTS

Of 37 patients, 12 were found to have smear-negative pTB and 25 were found to have an alternative diagnosis. Patients with tuberculosis had a median number of 17 ESAT-6-specific cells and 24.5 CFP-10-specific cells per 200,000 PBMCs and 37.5 ESAT-6-specific cells and 49.5 CFP-10-specific cells per 200,000 cells in the BAL fluid. Control patients had a median of 1 ESAT-6-specific cell and 1 CFP-10-specific cell per 200,000 PBMCs and no ESAT-6- and CFP-10-specific cells per 200,000 cells in the BAL fluid (p < 0.0001). All patients with TB but none of the control subjects had more than 5 spot-forming cells per 200,000 BALMCs with either peptide in the BAL fluid ELISPOT.

CONCLUSION

Smear-negative pulmonary tuberculosis can be diagnosed rapidly by identification of MTB-specific cells in the BAL fluid.