Characteristics of Patients with Smear-Negative Pulmonary Tuberculosis (TB) in a Region with High TB and HIV Prevalence

Clinical and Imaging Characteristics of Smear Negative Pulmonary Tuberculosis Patients: A Comparative Study

Background

Prevalence surveys in Ethiopia indicate smear negative pulmonary tuberculosis (SNPTB) taking the major share of the overall TB burden. It has also been a diagnostic dilemma worldwide leading to diagnostic delays and difficulty in monitoring treatment outcomes. This study determines and compares the clinical and imaging findings in SNPTB and smear positive PTB (SPPTB). Methodology. A case-control study was conducted on 313 PTB (173 SNPTB) patients. Data and sputum samples were collected from consented patients. Smear microscopy, GeneXpert, and culture analyses were performed on sputum samples. Data were analyzed using Stata version 17; a P value < 0.05 was considered statistically significant.

Results

Of the 173 SNPTB patients, 42% were culture positive with discordances between test results reported by health facilities and Armauer Hansen Research Institute laboratory using concentrated smear microscopy. A previous history of TB and fewer cavitary lesions were significantly associated with SNPTB.

Conclusions

Though overall clinical presentations of SNPTB patients resemble those seen in SPPTB patients, a prior history of TB was strongly associated with SNPTB. Subject to further investigations, the relatively higher discrepancies seen in TB diagnoses reflect the posed diagnostic challenges in SNPTB patients, as a higher proportion of these patients are also seen in Ethiopia.

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.

Tuberculosis-targeted next-generation sequencing and machine learning: An ultrasensitive diagnostic strategy for paucibacillary pulmonary tuberculosis and tuberculous meningitis

BACKGROUND

Existing diagnostic approaches for paucibacillary tuberculosis (TB) are limited by the low sensitivity of testing methods and difficulty in obtaining suitable samples.

METHODS

An ultrasensitive TB diagnostic strategy was established, integrating efficient and specific TB targeted next-generation sequencing and machine learning models, and validated in clinical cohorts to test plasma cfDNA, cerebrospinal fluid (CSF) DNA collected from tuberculous meningitis (TBM) and pediatric pulmonary TB (PPTB) patients.

RESULTS

In the detection of 227 samples, application of the specific thresholds of CSF DNA (AUC = 0.974) and plasma cfDNA (AUC = 0.908) yielded sensitivity of 97.01 % and the specificity of 95.65 % in CSF samples and sensitivity of 82.61 % and specificity of 86.36 % in plasma samples, respectively. In the analysis of 44 paired samples from TBM patients, our strategy had a high concordance of 90.91 % (40/44) in plasma cfDNA and CSF DNA with both sensitivity of 95.45 % (42/44). In the PPTB patient, the sensitivity of the TB diagnostic strategy yielded higher sensitivity on plasma specimen than Xpert assay on gastric lavage (28.57 % VS. 15.38 %).

CONCLUSIONS

Our TB diagnostic strategy provides greater detection sensitivity for paucibacillary TB, while plasma cfDNA as an easily collected specimen, could be an appropriate sample type for PTB and TBM diagnosis.

Prevalence and Risk Factors for Mycobacterium tuberculosis Infection among Health Workers in HIV Treatment Centers in North Central, Nigeria

Mycobacterium tuberculosis and HIV constitute a public health challenge. Health workers (HWs) in HIV clinics maybe at greater risk of M. tuberculosis infection, considering the high rates of HIV/tuberculosis (TB) coinfection among patients. Hence, we measured the prevalence of M. tuberculosis infection and the effect of working in an HIV clinic. We conducted a cross-sectional study in high-HIV burden health-care facilities in Abuja and Nasarawa states and recruited HWs over 4 months. We administered questionnaires and screened for M. tuberculosis infection using QuantiFERON-TB Gold-Plus. A total of 1,043 HWs were enrolled, with the majority being clinical staff (77.4%). Prevalence of interferon gamma release assay (IGRA) positivity was 44.8% (43.8% among HWs from HIV clinic and 45.3% from non-HIV clinics, P = 0.24). Nonoccupational factors such as living in a moderately (odds ratio [OR] = 0.71] or sparsely populated neighborhood (OR = 0.56), remained associated with a reduced risk of IGRA positivity, whereas male gender (OR = 1.37) and having high blood pressure (HBP) (OR = 1.52) remained associated with an increased risk after adjusting. Occupational factors such as length of career as a HW of 10 to 20 years (OR = 1.45) or 20 to 30 years (OR = 1.74) remained associated with an increased risk of IGRA positivity after adjusting. In a final multivariate model, the factors of age between 20 to < 30 years (OR = 0.61), having HBP (OR = 1.56), having a length of career as a HW of 10 to 20 years (OR = 1.66) or 20 to 30 years (OR = 2.09) and being a clinical HW (OR = 0.62) remained associated with IGRA positivity. There is a high prevalence of IGRA positivity among HWs in Nigeria. Working in HIV clinics, however, is not associated with increased risk.

Clinical application of metagenomic next-generation sequencing in tuberculosis diagnosis

Objective

The purpose of this study was to evaluate the clinical diagnostic value of metagenomic next-generation sequencing (mNGS) for tuberculosis (TB).

Methods

This retrospective study included 52 patients with suspected TB infection. mNGS, targeted PCR, acid-fast staining and, T-SPOT.TB assay were performed on the specimen. The positive rate of mNGS and traditional detection methods was statistically analyzed. Pathological tests were performed when necessary.

Results

In total, 52 patients with suspected of TB in this study were included in the analysis, and 31 patients were finally diagnosed with TB. Among 52 patients, 14 (26.9%) cases were positive for acid-fast staining. The positive rate of T-SPOT.TB assay in 52 patients was 73.1% (38/52). Among 52 patients, 39 (75%) were detected positive for Mycobacterium tuberculosis (MTB) by mNGS. Regarding the detection rate of MTB, mNGS were as high as 75% (39/52), whereas acid-resistant staining was only 26.9% (14/52), which showed a statistically significant difference (p&lt;0.05). The positive rates of T-SPOT.TB assay and mNGS were not statistically significant (p&gt;0.05). Of the 52 suspected TB patients, 24 had targeted PCR, of which 18 were PCR positive. In 24 patients, the positive rate of PCR was 75%, and the positive rate of mNGS was 100%, with statistical difference between them (p&lt;0.05).

Conclusions

The detection rate of MTB by mNGS was higher than that by conventional acid-fast staining and PCR, but not statistically significant compared with T-SPOT.TB assay. As an adjunctive diagnostic technology, mNGS can be combined with traditional detection methods to play a guiding role in the diagnosis and treatment of TB.

Diagnostic biomarkers for active tuberculosis: progress and challenges

Tuberculosis (TB) is a leading cause of morbidity and mortality from a single infectious agent, despite being preventable and curable. Early and accurate diagnosis of active TB is critical to both enhance patient care, improve patient outcomes, and break Mycobacterium tuberculosis (Mtb) transmission cycles. In 2020 an estimated 9.9 million people fell ill from Mtb, but only a little over half (5.8 million) received an active TB diagnosis and treatment. The World Health Organization has proposed target product profiles for biomarker- or biosignature-based diagnostics using point-of-care tests from easily accessible specimens such as urine or blood. Here we review and summarize progress made in the development of pathogen- and host-based biomarkers for active TB diagnosis. We describe several unique patient populations that have posed challenges to development of a universal diagnostic TB biomarker, such as people living with HIV, extrapulmonary TB, and children. We also review additional limitations to widespread validation and utilization of published biomarkers. We conclude with proposed solutions to enhance TB diagnostic biomarker validation and uptake.

Evaluation of Xpert MTB/RIF Assay, MTB Culture and Line Probe Assay for the Detection of MDR Tuberculosis in AFB Smear Negative Specimens

The global burden of tuberculosis (TB), particularly with multidrug resistance (MDR), is escalating and has become a major health challenge. It is well known that acid-fast bacilli (AFB) smear-negative TB patients are the major source of spreading TB to healthy individuals when left untreated. Early diagnosis of TB and rapid detection of drug resistance are important for the proper management of drug-resistant TB (DR-TB). Therefore, a laboratory based cross-sectional study was conducted from July to December 2019 at the National Tuberculosis Centre, Thimi, Nepal, with the objective of evaluating the diagnostic performance of Xpert MTB/RIF assay, Mycobacterium tuberculosis (MTB) culture and line probe assay (LPA) for the detection of MDR-TB in AFB smear-negative sputum samples. We evaluated a total of 222 AFB smear-negative sputum specimens, of which 21.6% (n = 48) showed MTB positive with Xpert MTB/RIF assay and, while culturing on Lowenstein-Jensen (LJ) media, 21.2% (n = 47) were MTB culture positive. The sensitivity, specificity, PPV and NPV at 95% confidence interval of Xpert MTB/RIF assay on diagnosing M. tuberculosis from smear-negative specimens were 73% (57-84), 92% (87-96), 71% (59-81) and 93% (89-95), respectively. In addition, the sensitivity of Xpert MTB/RIF assay and LPA in detecting rifampicin resistance was 75% (42-94, 95% CI) and 91.67% (62-99, 95% CI), respectively. The current study also assessed a significant association between the occurrence of pulmonary tuberculosis with different age group, TB history and alcohol consumption. These findings indicate that Xpert MTB/RIF assay and LPA are appropriate methods for early detection and accurate diagnosis of TB and RIF mono-resistant cases.

Effect of sputum quality and role of Xpert® MTB/ RIF assay for detection of smear-negative pulmonary tuberculosis in same-day diagnosis strategy in Addis Ababa, Ethiopia

Background

There is limited information on the performance of the Xpert® MTB/RIF test for diagnosis of smear-negative pulmonary tuberculosis (SNPT) and rifampicin resistance (RR) in the same-day diagnosis approach. The effects of sputum quality and other factors affecting the Xpert performance are also under-investigated.

Objective

This study aimed to determine the performance of the Xpert® MTB/RIF test for detection of SNPT and RR in the same-day diagnosis strategy and the effect of sputum quality and other factors on its performance.

Methods

A cross-sectional study was conducted from August 2017 to January 2018 across 16 health facilities in Addis Ababa, Ethiopia. Two spot sputum samples were collected from 418 presumptive SNPT patients, tested with Xpert® MTB/RIF, then compared to tuberculosis culture. Additionally, culture isolates were tested for RR by BACTEC MGIT™ 960 drug susceptibility testing (DST) and MTBDRplus version 2.

Results

The Xpert® MTB/RIF test detected 24 (5.7%) SNPT cases, with a sensitivity of 92.3% (75.9% - 97.9%) and specificity of 99.2% (97.8% - 99.7%) compared with tuberculosis culture. Xpert® MTB/RIF also detected three (11.58%) RR strains with 100.0% concordance with BACTEC MGIT™ 960 DST and MTBDRplus results. Three blood-stained SNPT samples were positive by Xpert (30.0%), which was 6.9 times higher compared to salivary sputum (odds ratio: 6.9, 95% confidence interval: 1.36-34.96, p = 0.020).

Conclusion

The performance of the Xpert® MTB/RIF to detect SNPT and RR in same-day diagnosis is high. However, SNPT positivity varies among sputum qualities, and good sample collection is necessary for better test performance.

Combining metabolome and clinical indicators with machine learning provides some promising diagnostic markers to precisely detect smear-positive/negative pulmonary tuberculosis

Background

Tuberculosis (TB) had been the leading lethal infectious disease worldwide for a long time (2014–2019) until the COVID-19 global pandemic, and it is still one of the top 10 death causes worldwide. One important reason why there are so many TB patients and death cases in the world is because of the difficulties in precise diagnosis of TB using common detection methods, especially for some smear-negative pulmonary tuberculosis (SNPT) cases. The rapid development of metabolome and machine learning offers a great opportunity for precision diagnosis of TB. However, the metabolite biomarkers for the precision diagnosis of smear-positive and smear-negative pulmonary tuberculosis (SPPT/SNPT) remain to be uncovered. In this study, we combined metabolomics and clinical indicators with machine learning to screen out newly diagnostic biomarkers for the precise identification of SPPT and SNPT patients.

Methods

Untargeted plasma metabolomic profiling was performed for 27 SPPT patients, 37 SNPT patients and controls. The orthogonal partial least squares-discriminant analysis (OPLS-DA) was then conducted to screen differential metabolites among the three groups. Metabolite enriched pathways, random forest (RF), support vector machines (SVM) and multilayer perceptron neural network (MLP) were performed using Metaboanalyst 5.0, “caret” R package, “e1071” R package and “Tensorflow” Python package, respectively.

Results

Metabolomic analysis revealed significant enrichment of fatty acid and amino acid metabolites in the plasma of SPPT and SNPT patients, where SPPT samples showed a more serious dysfunction in fatty acid and amino acid metabolisms. Further RF analysis revealed four optimized diagnostic biomarker combinations including ten features (two lipid/lipid-like molecules and seven organic acids/derivatives, and one clinical indicator) for the identification of SPPT, SNPT patients and controls with high accuracy (83–93%), which were further verified by SVM and MLP. Among them, MLP displayed the best classification performance on simultaneously precise identification of the three groups (94.74%), suggesting the advantage of MLP over RF/SVM to some extent.

Conclusions

Our findings reveal plasma metabolomic characteristics of SPPT and SNPT patients, provide some novel promising diagnostic markers for precision diagnosis of various types of TB, and show the potential of machine learning in screening out biomarkers from big data.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07694-8.

Mycobacterium tuberculosis antigen-specific T cell responses in smear- negative pulmonary tuberculosis patients

Despite recent improvements in microbial detection, smear negative TB remains a diagnostic challenge. In this study, we investigated the potential discriminatory role of polychromatic flow cytometry of M. tuberculosis antigen-specific T cells to discriminate smear negative TB from health controls with or without latent TB infection, and non-TB respiratory illnesses in an endemic setting. A cross-sectional study was conducted on HIV negative, newly diagnosed smear-positive PTB (n=34), smear-negative/Gene Expert negative PTB (n=29) patients, non-TB patients with respiratory illness (n=33) and apparently healthy latent TB infected (n = 30) or non-infected (n = 23) individuals. The expression of activation (HLA-DR, CD-38), proliferation (Ki-67) and functional (IFN-γ, TNF-α) T cell markers using polychromatic flow cytometry was defined after stimulation with PPD antigens. Sputum samples were collected and processed from all patients for Mtb detection using a concentrated microscopy, LJ/MGIT culture, and RD9 typing by PCR. Our study showed CD4 T cells specific for PPD co-expressed activation/proliferation markers together with induced cytokines IFNγ or TNFα were present at substantially higher levels among patients with smear positive and smear negative pulmonary TB than among healthy controls and to a lesser extent among patients with non-TB illness. Our study conclude that Smear negative TB can be distinguished from non-TB respiratory illness and healthy controls with a flow cytometric assay for PPD-specific T cells co-expressing activation/proliferation markers and cytokines.

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.

Real-World Performance Assessment of Xpert MTB/RIF Assay for Detecting Pulmonary Tuberculosis and Rifampin Resistance in a Single Tertiary Care Hospital in Korea

This study aimed at evaluating performance of Xpert MTB/RIF (Xpert) regarding detection of pulmonary tuberculosis compared to acid-fast bacilli (AFB) smear and culture, and concordance of rifampin resistance with drug susceptibility test. Specimens simultaneously referred for AFB smear, culture, and Xpert during April 2015 to March 2018 were retrospectively reviewed. Sensitivity, specificity, and mean cycle-threshold (C_t) values of Xpert and rifampin resistance results were analyzed. Results of Xpert for pulmonary tuberculosis were evaluated by AFB smear grade. Among the total of 3,840 specimens, 491 were positive in Xpert and 626 were positive in culture. Sensitivity and specificity of Xpert was 75.6% and 99.4%, respectively. Sensitivity of Xpert in smear-positive/culture-positive specimens was 98.6% and those of smear-negative and trace/culture-positive was 63.1%. Positivity of Xpert in culture-positive specimens were 89.9%/98.6%/95.7%/100.0%/100.0% in smear grade trace/1+/2+/3+/4+. Ct values of 491 specimens significantly lowered as AFB smear grade increased (p<0.0001). C_t of smear-positive/smear-trace/smear-negative specimens were 21.7 ± 4.2/26.5 ± 3.9/27.4 ± 3.6, respectively. Rifampin resistance tested by Xpert and culture was 98.3% concordant. Region covered by probe E was the most frequently mutated (50.0%). Xpert showed reliable performance in detecting pulmonary tuberculosis in smear-positive/culture-positive specimens and further improvements are needed for smear negative/culture positive specimens.

Microbiological Testing of Gastric Aspirate Improves the Diagnosis of Pulmonary Tuberculosis in Unconscious Adults with TB Meningitis

Conventional sputum collection for TB diagnosis is difficult in TB meningitis patients since most of them are admitted with decreased consciousness. It is assumed that unconscious patients swallow their sputum; therefore, gastric aspiration can replace sputum collection in unconscious patients. A prospective study was conducted to see whether examining gastric aspirate could increase the diagnosis certainty of pulmonary TB in such subjects. The inclusion criteria were age 18–60 years, decreased level of consciousness, and use of a nasogastric tube. Subjects who had taken antituberculosis drugs for more than 3 days were excluded. Gastric lavage was performed in the morning after an overnight fast. Specimens were examined for direct smear, culture, and rapid molecular testing. Demographic, clinical, chest X-ray, and laboratory data were also recorded. During the study period, 31 subjects were available. The positivity rates for microbiological tests were 19.3%, 41.9%, and 48.4% for smear, culture, and rapid molecular testing, respectively. All positive smears were confirmed by either culture or rapid molecular testing. Gastric lavage can be considered a tool for improving extraneural TB diagnosis in unconscious patients.

Diagnostic Accuracy of Sputum Microscopy in Comparison With GeneXpert in Pulmonary Tuberculosis

Background

Tuberculosis (TB) is a major health problem. In Pakistan, the diagnosis of pulmonary tuberculosis mainly relies on acid-fast bacilli (AFB) smear microscopy and Xpert® MTB/RIF assay (Cepheid Inc., Sunnyvale, CA) - a nucleic acid amplification test - where available. There is a wide variation in the reported sensitivity of Ziehl-Neelsen (ZN) smear microscopy across previous studies. This study aimed to determine the accuracy of sputum ZN smear microscopy in diagnosing pulmonary tuberculosis as compared with the sputum GeneXpert (Xpert MTB/RIF assay) as the reference test.

Materials and methods

This is a retrospective cross-sectional study conducted in the outpatient department of the Pakistan Institute of Medical Sciences. This study included 326 patients, aged 12 years and above, who had their sputum samples tested for ZN smear microscopy and GeneXpert during the period January to June 2019. Patients' demographic details, sputum ZN smear microscopy, and GeneXpert test results were collected for data analysis. A case of pulmonary tuberculosis was defined as a patient with positive sputum GeneXpert test result.

Results

Out of the 326 patients, GeneXpert detected MTB deoxyribonucleic acid (DNA) in 50 patients and ZN smear microscopy detected AFB in 30 patients. There was a marginal male predominance among GeneXpert positive cases. Adolescents were the least affected age group. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of ZN smear microscopy were 60%, 100%, 100%, 93.24%, and 93.87%, respectively. The positive likelihood ratio was infinite whereas the negative likelihood ratio was 0.4. The area under curve (AUC) for ZN smear microscopy was 0.800 and receiver operating characteristic (ROC) curve analysis revealed a diagonal straight line closer to the left upper corner.

Conclusion

Sputum ZN smear microscopy is a highly specific but moderately sensitive test for the diagnosis of pulmonary tuberculosis. This study recommends the sputum GeneXpert MTB/RIF test to avoid a missed diagnosis of smear-negative pulmonary TB.

Evaluation and comparison of molecular and conventional diagnostic modalities for detecting pulmonary tuberculosis in bronchoalveolar lavage fluid

CONTEXT

In cases of sputum smear-negative and sputum-scarce (SSN/SC) pulmonary tuberculosis (PTB), bronchoalveolar lavage (BAL) fluid may be helpful in establishing diagnosis. No specific recommendations for BAL samples have yet been formulated due to limited literature.

AIMS

1. To find a sensitive and specific protocol for same-day diagnosis of PTB using BAL in SSN/SC clinically suspected patients. 2. To evaluate the need to routinely perform MGIT for all BAL samples.

SETTINGS AND DESIGN

Prospective observational study design in a tertiary care hospital in New Delhi.

METHODS AND MATERIAL

Fibreoptic bronchoscopy was performed and BAL collected from 175 clinically suspected SSN/SC PTB patients. BAL samples were subjected to: ZN Stain, Xpert MTB/RIF CBNAAT, BACTEC MGIT 960 liquid culture and M. tuberculosis complex DNA Real time PCR. The results of the various diagnostic tests were analysed using a) MGIT as gold standard and b) a composite reference standard (CRS) for a final diagnosis of PTB.

STATISTICAL ANALYSIS USED

Microsoft Excel 2016 and SPSS version 21.0 were used. Sensitivity, specificity and predictive values were calculated and compared using McNemar test. A p value of <0.05 was considered statistically significant.

RESULTS

34 Cases had a final diagnosis of TB as per the CRS. Using CRS, MGIT had a sensitivity of 50.0% (32.4%-67.6%). There was no statistically significant difference between sensitivities of CBNAAT and PCR; both were more sensitive than ZN stain. Sensitivity and specificity of CBNAAT was 79.4% (62.1%-91.3%) and 100.0% (97.4%-100.0%) respectively. The preferred protocol for the hospital is CBNAAT and ZN stain. There was no statistically significant difference in sensitivity by adding PCR or MGIT to this protocol.

CONCLUSIONS

We found it a good strategy to perform CBNAAT and ZN stain on BAL fluid for accurate and same-day PTB diagnosis. CBNAAT is useful for ruling PTB in even when BAL cultures are negative. It is prudent to continue to routinely perform MGIT for all BAL samples.

Clinical Spectrum and Medical Comorbidities in Tuberculosis: A Hospital-Based Study in Northeast India

Background

Tuberculosis (TB) is one of the most common infectious diseases and is commonly associated with comorbidities. However, data regarding TB and comorbidities are lacking from northeast India. The aim of the study is to see the clinical spectrum of TB and the frequency of comorbidities.

Methods

This was a prospective observational study of all hospitalized TB patients between January 2016 and June 2017 who were selected by consecutive sampling. Data were analyzed using SPSS v. 17.0 (IBM Corp., Armonk, NY), and a p-value of <0.05 was considered significant.

Results

Of the 173 patients selected, the mean age was 41.05±17.04 years with a male:female ratio of 4.27:1. Pulmonary TB (PTB) was found in 43.94%, extra-pulmonary TB (EPTB) in 52.02%, and disseminated TB in 4.04%. Fever (61.27%) was the most common presentation, followed by cough (54.33%) and breathlessness (32.94%). Of the 76 patients with PTB and seven with disseminated TB, making a total of 83 patients, 56 (67.4%) were sputum positive. Out of 90 patients suffering from EPTB, pleural effusion (53.33%) was the commonest type of EPTB, followed by central nervous system (CNS) tuberculosis (26.66%) and abdominal tuberculosis (8.88%). Comorbidities were present in 53.17% of the patients, of which diabetes mellitus (DM) (26.58%) and hypertension (17.34%) were the most common. Comorbid conditions were significantly higher in PTB than EPTB (51 of 83 vs. 41 of 90, p<0.05). Mean glycated hemoglobin (HbA1c) was significantly higher in PTB as compared to EPTB (8.74±2.04 vs. 7.58±0.29, p<0.05).

Conclusion

Comorbidities, particularly DM, were present in half of the patients, mostly in PTB than EPTB, with glycemic control being significantly poorer in PTB patients.

A descriptive study of smear negative pulmonary tuberculosis in a high HIV burden patient's population in North Central Nigeria

Tuberculosis (TB) is a serious disease of public health concern, mainly in low- and middle-income countries. Most of these countries have challenges in diagnosis and treatment of TB in people with smear-negative pulmonary tuberculosis (SNPTB), which remains a significant public health challenge because of the global burden of the disease. We evaluated the epidemiology and clinical presentation of SNPTB in a cohort of patients with high HIV burden. The study was a cross-sectional study among patients with SNPTB in four major hospitals that care for TB/HIV patients in north-central Nigeria. All patients 18 years and above who were newly diagnosed as SNPTB, or patients with SNPTB who had not taken TB drugs for up to 2 weeks irrespective of their HIV status were recruited. Demographic data (sex, age), smoking status, and medical history (clinical form of TB, symptoms at admission, diagnostic methods, presence of comorbidities, prior TB treatment) were obtained using a semi-structured questionnaire. Detailed clinical examination was also done on all the study subjects. Baseline results of packed cell volume, HIV test and sputum acid fast bacilli done during TB screening were retrieved from the patients' case notes and recorded. Also, the base line Chest X-ray films taken during TB screening were reviewed and reported by two radiologists blinded to each other's reports. The Xpert MTB/RIF tests and sputum culture (using LJ medium) were done in a TB reference laboratory. A total of 150 patients with SNPTB were studied. Majority of the patients were female 93 (62%). The median age of the patients was 36.5 years with greater percentage of the patients within the ages of 25-44 years 92 (61.3%). Twenty-two (14.7%) of the patients had previous TB treatment. History of cigarette smoking was obtained in only 7(4.7%) of the patients while 82 (64.1%) were HIV positive. All the patients had a history of cough for over a period of at least three weeks, while, 27 (18%) reported having hemoptysis. About 87 (58%) had fever and 110 (73.7%) had anemia, while weight loss and night sweat were reported in 98(65.3%) and 82 (54.7%) of the patients respectively. Chest x rays were reported as typical of TB in only 24 (16%) of the patients. Of the 150 sputa sample analyzed, 21/150 (14.0%) and 22/150 (14.7%) where Gene Xpert and sputum culture positive respectively. The sensitivity and specificity of Gene Xpert assay were 81.8% (18/22; 95% CI 61.5 to 92.7%) and 97.4% (112/115; 95% CI 92.6 to 99.1%), respectively. The study found cough, fever and anemia to be the commonest presentation in patient with SNPTB in a high HIV burden patient's population. There is also relatively high culture positivity among the patients. This underscores the need to expand the facilities for culture and confirmation in TB centers across the country.

Characteristics Indicative of Tuberculosis/HIV Coinfection in a High-Burden Setting: Lessons from 13,802 Incident Tuberculosis Cases in Harare, Zimbabwe

Country-specific interventions targeting high-risk groups are necessary for a global reduction in Tuberculosis (TB)/HIV burden. We analyzed the data of 13,802 TB cases diagnosed in Harare, Zimbabwe, during 2013-2017. Pearson's chi-square tests and multivariate logistic regression models were used to identify patient characteristics significantly associated with TB/HIV coinfection. Of the 13,802 TB cases analyzed, 9,725 (70.5%) were HIV positive. A significantly higher odds of having TB/HIV coinfection diagnosis was found among females, patients aged 25-64 years, previously treated cases, and acid-fast bacillus sputum smear-negative cases. Compared with nondisseminated pulmonary TB, miliary TB (adjusted odds ratio [aOR]: 1.469, 95% CI: 1.071, 2.015) and TB meningitis (aOR: 1.715, 95% CI: 1.074, 2.736) both had a significantly higher odds for TB/HIV coinfection, whereas pleural TB (aOR 0.420, 95% CI: 0.354, 0.497) and all other extrapulmonary TB (EPTB) (aOR: 0.606, 95% CI: 0.516 0.712) were significantly less likely to have TB/HIV coinfection. The risk for TB/HIV coinfection varied significantly by patients' sociodemographic and clinical characteristics in Harare. Our finding that different forms of EPTB have different relationships with HIV coinfection has extended the knowledge base about clinical markers for TB/HIV coinfection which can lead to a greater public health impact on eliminating TB/HIV infection.

Mobilising community networks for early identification of tuberculosis and treatment initiation in Cambodia: an evaluation of a seed-and-recruit model

Background and objectives

The effects of active case finding (ACF) models that mobilise community networks for early identification and treatment of tuberculosis (TB) remain unknown. We investigated and compared the effect of community-based ACF using a seed-and-recruit model with one-off roving ACF and passive case finding (PCF) on the time to treatment initiation and identification of bacteriologically confirmed TB.

Methods

In this retrospective cohort study conducted in 12 operational districts in Cambodia, we assessed relationships between ACF models and: 1) the time to treatment initiation using Cox proportional hazards regression; and 2) the identification of bacteriologically confirmed TB using modified Poisson regression with robust sandwich variance.

Results

We included 728 adults with TB, of whom 36% were identified via the community-based ACF using a seed-and-recruit model. We found community-based ACF using a seed-and-recruit model was associated with shorter delay to treatment initiation compared to one-off roving ACF (hazard ratio 0.81, 95% CI 0.68-0.96). Compared to one-off roving ACF and PCF, community-based ACF using a seed-and-recruit model was 45% (prevalence ratio (PR) 1.45, 95% CI 1.19-1.78) and 39% (PR 1.39, 95% CI 0.99-1.94) more likely to find and detect bacteriologically confirmed TB, respectively.

Conclusion

Mobilising community networks to find TB cases was associated with early initiation of TB treatment in Cambodia. This approach was more likely to find bacteriologically confirmed TB cases, contributing to the reduction of risk of transmission within the community.

Bayesian reconstruction of Mycobacterium tuberculosis transmission networks in a high incidence area over two decades in Malawi reveals associated risk factors and genomic variants

Understanding host and pathogen factors that influence tuberculosis (TB) transmission can inform strategies to eliminate the spread of Mycobacterium tuberculosis (Mtb). Determining transmission links between cases of TB is complicated by a long and variable latency period and undiagnosed cases, although methods are improving through the application of probabilistic modelling and whole-genome sequence analysis. Using a large dataset of 1857 whole-genome sequences and comprehensive metadata from Karonga District, Malawi, over 19 years, we reconstructed Mtb transmission networks using a two-step Bayesian approach that identified likely infector and recipient cases, whilst robustly allowing for incomplete case sampling. We investigated demographic and pathogen genomic variation associated with transmission and clustering in our networks. We found that whilst there was a significant decrease in the proportion of infectors over time, we found higher transmissibility and large transmission clusters for lineage 2 (Beijing) strains. By performing evolutionary convergence testing (phyC) and genome-wide association analysis (GWAS) on transmitting versus non-transmitting cases, we identified six loci, PPE54, accD2, PE_PGRS62, rplI, Rv3751 and Rv2077c, that were associated with transmission. This study provides a framework for reconstructing large-scale Mtb transmission networks. We have highlighted potential host and pathogen characteristics that were linked to increased transmission in a high-burden setting and identified genomic variants that, with validation, could inform further studies into transmissibility and TB eradication.

Mortality Among People With HIV Treated for Tuberculosis Based on Positive, Negative, or No Bacteriologic Test Results for Tuberculosis: The IeDEA Consortium

Background

In resource-constrained settings, many people with HIV (PWH) are treated for tuberculosis (TB) without bacteriologic testing. Their mortality compared with those with bacteriologic testing is uncertain.

Methods

We conducted an observational cohort study among PWH ≥15 years of age initiating TB treatment at sites affiliated with 4 International epidemiology Databases to Evaluate AIDS consortium regions from 2012 to 2014: Caribbean, Central and South America, and Central, East, and West Africa. The exposure of interest was the TB bacteriologic test status at TB treatment initiation: positive, negative, or no test result. The hazard of death in the 12 months after TB treatment initiation was estimated using a Cox proportional hazard model. Missing covariate values were multiply imputed.

Results

In 2091 PWH, median age 36 years, 53% had CD4 counts ≤200 cells/mm³, and 52% were on antiretroviral therapy (ART) at TB treatment initiation. The adjusted hazard of death was higher in patients with no test compared with those with positive test results (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.08–2.26). The hazard of death was also higher among those with negative compared with positive tests but was not statistically significant (HR, 1.28; 95% CI, 0.91–1.81). Being on ART, having a higher CD4 count, and tertiary facility level were associated with a lower hazard for death.

Conclusions

There was some evidence that PWH treated for TB with no bacteriologic test results were at higher risk of death than those with positive tests. Research is needed to understand the causes of death in PWH treated for TB without bacteriologic testing.

Diagnosis of tuberculosis from smear-negative presumptive TB cases using Xpert MTB/Rif assay: a cross-sectional study from Nepal

BACKGROUND

In most developing countries, smear-negative pulmonary TB (SNPT) often gets missed from the diagnosis of consideration, though it accounts 30-65% of total PTB cases, due to deficient or inaccessible molecular diagnostic modalities.

METHODS

The cross-sectional study enrolled 360 patients with clinical-radiological suspicion of SNPT in Tribhuvan University Teaching Hospital (TUTH). The patient selection was done as per the algorithm of Nepal's National Tuberculosis Program (NTP) for Xpert MTB/RIF testing. Participants' demographic and clinical information were collected using a pre-tested questionnaire. The specimens were collected, processed directly for Xpert MTB/RIF test according to the manufacturer's protocol. The same samples were stained using the Ziehl-Neelsen technique then observed microscopically. Both findings were interpreted; rifampicin-resistant, if obtained, on Xpert testing was confirmed with a Line Probe Assay.

RESULT

Of 360 smear-negative sputum samples analyzed, 85(23.61%) found positive while 3(0.8%) of them were rifampicin resistance. The infection was higher in males, i.e. 60(25.3%) compared to female 25(20.3%). The age group, > 45(nearly 33%) with median age 42 ± 21.5, were prone to the infection. During the study period, 4.6% (515/11048) sputum samples were reported as smear-positive in TUTH. Consequently, with Xpert MTB/RIF assay, the additional case 16.5% (n = 85/515) from smear-negative presumptive TB cases were detected. Among the most occurring clinical presentations, cough and chest pain were positively associated with SNPT. While upper lobe infiltrates (36.4%) and pleural effusion (40.4%) were the most peculiar radiological impression noted in PTB patient. 94 multi-drug resistant(MDR) suspected cases were enrolled; of total suspects, 29(30.8%) samples were rifampicin sensitive, 1(1.06%) indeterminate, 3(3.19%) rifampicin-resistant while remaining of them were negative. 2(2.2%) MDR cases were recovered from the patient with a previous history of ATT, of total 89 previously treated cases enrolled However, a single rifampicin-resistant from the new suspects.

CONCLUSION

With an application of the assay, the additional cases, missed with smear microscopy, could be sought and exact incidence of the diseases could be revealed.

Predicting the risk of pulmonary tuberculosis based on the neutrophil-to-lymphocyte ratio at TB screening in HIV-infected individuals

Background

The neutrophil to lymphocyte ratio (NL ratio) has been reported to be a predictive biomarker of tuberculosis (TB). We assessed the association between the NL ratio and the incidence of active TB cases within 1 year after TB screening among HIV-infected individuals in Thailand.

Methods

A day care center that supports HIV-infected individuals in northernmost Thailand performed TB screening and follow-up visits. We compared the baseline characteristics between the TB screening positive group and the TB screening negative group. The threshold value of NL ratio was determined by cubic-spline curves and NL ratios were categorized as high or low NL ratio. We assessed the association between NL ratio and progression to active TB within 1-year using the Cox-proportional hazard model.

Results

Of the 1064 HIV-infected individuals who screened negative for TB at baseline, 5.6% (N = 60) eventually developed TB and 26 died after TB diagnosis. A high NL ratio was associated with a higher risk of TB (adjusted hazard ratio (aHR) 2.19, 95% CI: 1.23–3.90), after adjusting for age, sex, ethnicity, CD4 counts, and other risk factors. A high NL ratio in HIV-infected individuals with normal chest X-ray predicted TB development risk. In particular, a high NL ratio with TB symptoms could predict the highest risk of TB development (aHR 2.58, 95%CI: 1.07–6.23).

Conclusions

Our results showed that high NL ratio increased the risk of TB. NL ratio combined with TB symptoms could increase the accuracy of TB screening among HIV-infected individuals.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4292-9) contains supplementary material, which is available to authorized users.

HIV prevalence, knowledge and self-perceived risk of HIV infection among tuberculosis patients in Serbia

OBJECTIVE

The aim of the study was to estimate the seroprevalence of HIV infection among TB patients, knowledge, self-perceived risks and testing practices related to HIV.

METHODS

We performed cross-sectional study from 10 May to 15 July 2011. Cluster sampling method was used to select 27 hospitals where 289 TB patients were consecutively recruited. Descriptive statistics and multivariable logistic regression methods were used to identify the factors associated with correct comprehensive knowledge of HIV/AIDS.

RESULTS

HIV prevalence among TB patients was 0.3%. Only 25.2% of the respondents presented comprehensive correct knowledge of HIV/AIDS. The percentage of correct answers to all questions related to knowledge about HIV/AIDS increases with educational status (χ² = 5.42; p &lt; 0.05) and decreases with the age of respondents (χ² = 8.53; p &gt; 0.05). The independent predictors of correct comprehensive knowledge were living without partner (OR = 4.45; CI = 1.59-12.95) and self-awareness of HIV risk (OR = 4.43; CI = 1.20-16.52).

CONCLUSION

HIV prevalence among TB patients is higher than among general population in Serbia. The level of comprehensive correct knowledge of HIV/AIDS is low. There is a need for continuous implementation of public health strategy to successfully manage HIV and HIV/TB co-infection in Serbia.

Comparison of Quantamatrix Multiplexed Assay Platform and GenoType MTBDR Assay Using Smear-Positive Sputum Specimens From Patients With Multidrug- Resistant/Extensively Drug-Resistant Tuberculosis in South Korea

Rapid detection of drug-resistant tuberculosis (DR-TB) is crucial for timely treatment and management. The GenoType MTBDRplus and MTBDRsl (MTBDR) assays have been endorsed by the World Health Organization (WHO) for the detection of DR-TB. However, MTBDR assays cannot simultaneously detect multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Furthermore, interpretation of the MTBDR assay requires trained people, and the assay has low sample throughput, processing only up to 12 samples in parallel. We have developed the Quantamatrix Multiplexed Assay Platform (QMAP) to detect MDR-/XDR-TB simultaneously. The interpretation of QMAP results is automated, and the platform can process up to 96 samples in parallel. To compare the performance of QMAP with MTBDR assays, we performed QMAP and the MTBDR assay on 76 smear-positive, Mycobacterium tuberculosis culture-positive sputum specimens. Compared with phenotypic drug susceptibility testing (DST) results, the sensitivity and specificity of QMAP were 100 and 98% for rifampin resistance, 80 and 100% for isoniazid resistance, 44.4 and 100% for ethambutol resistance, 100 and 100% for fluoroquinolone resistance, and 100 and 100% for second-line injectable drug resistance, respectively. The sensitivity and specificity of MTBDR assays were 100 and 98% for rifampin resistance, 80 and 100% for isoniazid resistance, 44.4 and 98.1% for ethambutol resistance, 100 and 100% for fluoroquinolone resistance, and 100 and 100% for second-line injectable drug resistance, respectively. The sensitivity and specificity of QMAP were 85.0 and 100%, respectively, for the detection of MDR-TB and 100 and 100%, respectively, for XDR-TB. The sensitivity and specificity of MTBDR assays was consistent with those of QMAP. Our study showed that the QMAP assay has sensitivity and specificity equivalent to that of MTBDR assays in smear-positive sputum specimens. In combination with phenotypic DST, QMAP might be useful as a supplementary DST assay for rapid detection of MDR-/XDR-TB.

An Observational Case-Control Study to Determine Human Immunodeficiency Virus and Host Factor Influence on Biomarker Distribution and Serodiagnostic Potential in Adult Pulmonary Tuberculosis

Influence of host factors, including human immunodeficiency virus (HIV) co-infection, on the distribution and diagnostic potential of previously evaluated biomarkers of pulmonary tuberculosis (PTB), such as anti-antigen 60 (A60) immunoglobulin (Ig) G, anti-A60 IgA, and C-reactive protein (CRP), remain unclear. Anti-A60 IgG, anti-A60 IgA, and CRP in PTB and non-PTB patient sera (n = 404, including smear-positive/negative, culture-positive (SPCP/SNCP) and HIV+ve/-ve) were measured by enzyme-linked immunoassay and statistically analysed. In multinomial logistic regression, expectoration, chest pain, wasting, and culture count positively associated with CRP (p < 0.001), while smear count positively associated with anti-A60 IgG (p = 0.090). Expectoration and enlarged lymph nodes negatively associated with anti-A60 IgA (p = 0.018). Biomarker distribution and diagnostic potential varied significantly by symptoms and bacilli burden, and across different PTB subpopulations. CRP was correlated poorly with anti-A60 antibodies, while anti-A60 IgA and IgG were correlated in non-tuberculosis (TB) and SPCP patients (p < 0.001). When combined, anti-A60 IgG and CRP best discriminated SPCP/HIV-ve from non-TB (AUC: 0.838, 95% CI: 0.783⁻0.894), while anti-A60 IgA and CRP performed best in discriminating HIV+ve PTB from non-TB (AUC: 0.687, 95% CI: 0.598⁻0.777). Combined CRP and anti-A60 antibodies had significantly reduced accuracy in SNCP and SNCP/HIV+ve compared to SPCP/HIV-ve subpopulations. The complex relationships between host factors and biomarkers suggest their limited utility, especially in SNCP/HIV+ve subpopulations, highlighting the importance of examining host response and immune biomarkers across relevant patient subpopulations.

Xpert MTB/RIF Ultra improved the diagnosis of paucibacillary tuberculosis: A prospective cohort study

OBJECTIVES

We assessed the diagnostic performance of Xpert MTB/RIF Ultra (Xpert Ultra) in comparison to Xpert MTB/RIF (Xpert) for the detection of paucibacillary tuberculosis (TB).

METHODS

Smear-negative sputum, pleural fluid and cerebrospinal fluid (CSF) were collected from TB suspects at Beijing Chest Hospital (Beijing, China) and were examined using smear, Xpert and culture. Xpert Ultra was tested using specimens stored at -80 °C. Drug susceptibility testing (DST) was conducted for all of the isolates recovered. The performances of Xpert Ultra and Xpert were evaluated using composite reference standard (CRS) as gold standard, which included clinical, laboratory, histopathological, radiological and follow-up features.

RESULTS

Totally 689 cases were included. The direct head-to-head diagnostic performance comparison showed higher sensitivity of Xpert Ultra in contrast with Xpert among 292 smear-negative pulmonary TB (PTB) (70.89% vs 57.88%, P = 0.001), 108 tuberculous pleurisy (61.11% vs 34.26%, P<0.001), and 43 tuberculous meningitis (44.19% vs 18.60%, P = 0.011). The percentage of definite PTB, tuberculous pleurisy and tuberculous meningitis increased from 67.12% to 78.77%, 61.11% to 69.44% and 23.26% to 51.16%, respectively after integrating Xpert Ultra outcomes. The specificity of Xpert Ultra and Xpert was 96.75% (238/246) and 98.37% (242/246), respectively. Xpert Ultra and Xpert performed similarly in detecting rifampicin resistance.

CONCLUSION

Xpert Ultra has higher sensitivity but relatively reduced specificity compared with Xpert in diagnosis of paucibacillary TB. Performing Xpert Ultra would improve the definite diagnosis of smear-negative pulmonary tuberculosis, tuberculous pleurisy and tuberculous meningitis.

Predictors of mortality among intensive care unit patients coinfected with tuberculosis and HIV

Objective:

To identify factors predictive of mortality in patients admitted to the ICU with tuberculosis (TB)/HIV coinfection in the Manaus, Amazon Region.

Methods:

This was a retrospective cohort study of TB/HIV coinfected patients over 18 years of age who were admitted to an ICU in the city of Manaus, Brazil, between January of 2011 and December of 2014. Sociodemographic, clinical, and laboratory variables were assessed. To identify factors predictive of mortality, we employed a Cox proportional hazards model.

Results:

During the study period, 120 patients with TB/HIV coinfection were admitted to the ICU. The mean age was 37.0 ± 11.7 years. Of the 120 patients evaluated, 94 (78.3%) died and 62 (66.0%) of those deaths having occurred within the first week after admission. Data on invasive mechanical ventilation (IMV) and ARDS were available for 86 and 67 patients, respectively Of those 86, 75 (87.2%) underwent IMV, and, of those 67, 48 (71.6%) presented with ARDS. The factors found to be independently associated with mortality were IMV (p = 0.002), hypoalbuminemia (p = 0.013), and CD4 count < 200 cells/mm³ (p = 0.002).

Conclusions:

A high early mortality rate was observed among TB/HIV coinfected ICU patients. The factors predictive of mortality in this population were IMV, hypoalbuminemia, and severe immunosuppression.

Impact of introduction of Xpert MTB/RIF test on tuberculosis (TB) diagnosis in a city with high TB incidence in Brazil

Background

Xpert MTB/RIF is increasingly used in many countries as the initial diagnostic test for tuberculosis (TB). Few studies have evaluated the effect of Xpert on TB diagnosis under programmatic conditions in Brazil. The aim of the present study was to evaluate the impact of introduction of Xpert MTB/RIF on TB diagnosis in a city with high TB incidence in Brazil.

Methods

We included patients evaluated with conventional diagnostic tests during one year before Xpert introduction (pre-Xpert group) and patients evaluated using Xpert during one year after the test introduction (post-Xpert group).

Results

620 patients met the inclusion criteria (208 in the pre-Xpert group and 412 in the post-Xpert group) and were included in the analysis. The time until TB diagnosis was shorter in post-Xpert group (0.7 day, IQR: 0.5–1.0 day) than in pre-Xpert group (2.0 days, IQR: 2.0–2.0 days) (p<0.0001). Atypical disease characteristics, such as less weight loss, fever, dyspnea, night sweats, and hemoptysis; a negative sputum smear; a negative culture, and a chest X-ray atypical of TB were more common in post-Xpert group than in pre-Xpert group (p<0.0001 for all).

Conclusions

We found that the implementation of the Xpert MTB/RIF assay, under programmatic conditions, improve and facilitate TB diagnosis, especially in cases with atypical disease manifestations. These results are likely to be generalizable to settings with a similar high TB incidence.

Antigens Rv0310c and Rv1255c are promising novel biomarkers for the diagnosis of Mycobacterium tuberculosis infection

This study aimed to identify novel immunogenic epitopes from Mycobacterium tuberculosis (MTB) that could be used in tuberculosis (TB) diagnostics. To determine the diagnostic potential of mycobacterial antigens in serodiagnosis of TB, 256 patients were enrolled in a study and divided into two groups: 126 smear-positive pulmonary TB patients (SPPT) and 130 smear-negative pulmonary TB patients (SNPT); 152 bacillus Calmette-Guerin (BCG)-vaccinated healthy people were used as a control. Murine results showed that antigens Rv0310c-E from RD 8 and Rv1255c-E from RD 10 were strongly immunogenic to Th1 cells and induced a great humoral response. Receiver operating characteristic analysis indicated that Rv0310c-E (area under the curve (AUC): 0.800) and Rv1255c-E (AUC: 0.808) performed better than ESAT-6 (AUC: 0.665) and CFP-10 (AUC: 0.623) proteins but were comparable with Rv3425 (AUC: 0.788) protein in a human serum IgG analysis. Rv0310c-E demonstrated the highest diagnostic ability for the SPPT group (Youden index: 0.5602, sensitivity: 69.84%, specificity: 86.18%), while Rv1255c-E demonstrated the highest diagnostic ability for the SNPT group (Youden index: 0.5674, sensitivity: 73.84%, specificity: 82.89%). In addition, combination analysis found that antigen Rv0310c-E, coupled with the Rv3425 protein (Youden index: 0.6098, sensitivity: 87.30%, specificity: 73.68%) had the strongest performance for TB diagnostics of the SPPT group, and the single antigen Rv1255c-E was strongest for the SNPT group. These results suggest that antigens Rv0310c-E and Rv1255c-E are potential antigens for TB serodiagnostic tests, which may facilitate detection of MTB in smear-negative and smear-positive patients.

Epidemiologic Trend of Smear-Positive, Smear-Negative, Extra Pulmonary and Relapse of Tuberculosis in Iran (2001-2015); A Repeated CrossSectional Study

Background: Trend analysis is an important tool to monitor epidemiological changes of disease over time to guide resource allocation. This study aimed to study incidence trends and change-points of smear positive, smear negative, extra-pulmonary and relapse of tuberculosis (TB) in Iran from 2001 to 2015.

Study design: Repeated cross-sectional study

Methods:Nonlinear segmented regression w as used to describe TB incidence trends; annual percent change (APC), average annual percent changes (AAPC) and change points for each disease separately.

Results: Of 154930 TB cases, 49.8% w ere smear positive, 19.7% smear negative, 27.32% extrapulmonary and 3.18% relapse. For all TB types, the peak of incidence w as in 2001. Tw o change point w ere estimated for all TB types (P<0.05). The APC of all TB types w ere -6.51 (95% CI: -7.4, -5.4) for first and 2.4 (95% CI: 0. 7, 4.1) for second segment. Although the trends w ere significantly decreasing from 2001 to 2015 for smear positive (AAPC=2.06%), smear negative (AAPC=3.57%), extra pulmonary (AAPC=3.2%) and relapse (AAPC=3.3%), the AAPCs of trends w ere not significant from 2006 to 2015. Except for Extra pulmonary TB (APC=4-.9%, 95%CI:-10, 1.2), the APCs of the last segments w ere significant.

Conclusions:Even though the TB incidence rates w ere decreasing, the amount of reductions seem inadequate, to reach the goals of TB control in Iran. Especially, the increase in the extra-pulmonary TB rates is a point of concern that highlights more attention is required for these cases. It is essential to improve economic supports tow ard TB control, illegal immigrants, data registry systems and physician's sensitivity in TB detection.