The Acid-Fast Bacilli Smear: Hail and Farewell.
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ABSTRACT:
SUBMITTER: Schluger NW
PROVIDER: S-EPMC6423104 | biostudies-literature | 2019 Mar
REPOSITORIES: biostudies-literature
Publications
The Acid-Fast Bacilli Smear: Hail and Farewell.
American journal of respiratory and critical care medicine 20190301 6
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Project description:IntroductionNontuberculous mycobacteria (NTM) and pulmonary tuberculosis (PTB) are difficult to distinguish in initial acid-fast bacilli (AFB) smear-positive patients.ObjectivesEstablish a predictive model to identify more effectively NTM infections in initial AFB patients.MethodsConsecutive AFB smear-positive patients in the Respiratory Department of Shanghai Pulmonary Hospital from January 2019 to February 2020 were retrospectively analysed. A multivariate regression was used to determine the independent risk factors for NTM. A receiver operating characteristic (ROC) curve was used to determine the model's predictive discrimination. The model was validated internally by a calibration curve and externally for consecutive AFB smear-positive patients from March to June 2020 in this institution.ResultsPresenting with haemoptysis, bronchiectasis, a negative QuantiFERON tuberculosis (QFT) test and being female were characteristics significantly more common in patients with NTM (P ≤ 0.001), when compared with PTB. The involvement of right middle lobe, left lingual lobe and cystic change was more commonly seen on chest high-resolution computed tomography (HRCT) in patients with NTM (P < 0.05), compared with PTB. Multivariate regression showed female, bronchiectasis, negative test for QFT and right middle lobe lesion were independent risk factors for NTM (P < 0.05). A ROC curve showed a sensitivity and specificity of 85.9% and 93.4%, respectively, and the area under the curve (AUC) was 0.963. Moreover, internal and external validation both confirmed the effectiveness of the model.ConclusionsThe predictive model would be useful for early differential diagnosis of NTM in initial AFB smear-positive patients.
| S-EPMC9290942 | biostudies-literature
Project description:BackgroundVitamin D is related to human immunity, so we used Bayesian network model to analyze and infer the relationship between vitamin D level and the acid-fast bacilli (AFB) smear-positive after two months treatment among pulmonary tuberculosis (TB) patients.MethodsThis is a cross-sectional study. 731 TB patients whose vitamin D level were detected and medical records were collected from December 2019 to December 2020 in XinJiang of China. Logistic regression was used to analyze the influencing factors of second AFB smear-positive. Bayesian network was used to further analyze the causal relationship among vitamin D level and the second AFB smear-positive.ResultsBaseline AFB smear-positive (OR = 6.481, 95%CI: 1.604~26.184), combined cavity (OR = 3.204, 95%CI: 1.586~6.472), full supervision (OR = 8.173, 95%CI:1.536~43.492) and full management (OR = 6.231, 95%CI:1.031~37.636) were not only the risk factors and can also be considered as the reasons for second AFB smear-positive in TB patients (Ensemnle > 0.5). There was no causal relationship between vitamin D level and second AFB smear-positive (Ensemnle = 0.0709).ConclusionsThe risk factors of second AFB smear-positive were baseline AFB smear-positive, combined cavity, full supervision and full management. The vitamin D level in TB patients was not considered as one of the reasons for the AFB smear-positive.
| S-EPMC9067663 | biostudies-literature
Project description:BackgroundThere is a paucity of data on the role of molecular methods in the diagnosis of osteoarticular tuberculosis. The present study was conducted to define the role of molecular (CBNAAT, LPA), phenotypic (AFB smear and culture) and histopathological evaluation in the diagnosis of osteoarticular TB.MethodsSeventy-seven consecutive cases of osteoarticular tuberculosis were grouped into presumptive TB cases (group A) and presumptive drug-resistant cases (group B). Tissue samples obtained were submitted for CBNAAT, LPA, AFB smear, liquid culture and histological examinations. The diagnostic accuracy of each test was reported against histologically diagnosed cases and in all tests in tandem.ResultsGroup A and group B had 65 and 12 cases, respectively. The diagnostic accuracy for tuberculosis was 84.62% by CBNAAT, 70.77% by LPA, 86.15% by molecular tests (combined), 47.69% by AFB smear, 50.77% by liquid culture and 87.69% by histology in group A, and 91.67% for CBNAAT, 83.33% for LPA, 91.67% for molecular tests (combined), 25% for AFB smear, 16.67% for liquid culture and 83.33% for histology in group B. The drug resistance detection rate was 4.62% on CBNAAT, 3.08% on LPA, 6.15% on molecular tests (combined) and 1.54% on DST in group A, while it was 33.33% on CBNAAT, 58.33% on LPA, 58.33% on molecular tests (combined) and 16.67% on DST among group B cases. Similar sensitivity rates for the various tests were obtained among both the groups on comparison with histology (taken as denominator). The addition of molecular methods increased the overall diagnostic accuracy (all tests in tandem) from 93.8 to 100% in group A and from 83.3 to 100% in group B cases.ConclusionNo single tests could diagnose tuberculosis in all cases; hence, samples should be evaluated by molecular tests (CBNAAT and LPA), AFB smear, culture and histological examinations simultaneously. The molecular tests have better demonstration of drug resistance from mycobacterial culture.Supplementary informationThe online version contains supplementary material available at 10.1007/s43465-020-00326-w.
| S-EPMC8149538 | biostudies-literature
Project description:Sputum from 105 cases of pulmonary tuberculosis were studied. Direct and post concentration smears were stained by Ziehl - Neelsen (ZN) and cold staining methods. The cold staining method is simple, because it eliminates heatingof stain. For direct smear, the correlations of cold staining procedure with conventional ZN method was 93% and for post concentration smear it was 100%.
| S-EPMC5529720 | biostudies-other
Project description:BackgroundAccording to the Global Tuberculosis Report 2015, Indonesia ranked as second country in the world with the highest number of pulmonary tuberculosis cases. By 2015, the number of pulmonary TB new cases in Indonesia has increased to 330.910 cases of 2014 where 324.539 cases. DM is one of the most important factors that influence the occurrence worsening TB. Now is known that DM patients have body's immune response disorder thereby facilitating M. tuberculosis infection and causing TB.MethodThis research is cross sectional design. The sample in this research are adult pulmonary TB patients at General Hospital Grade C period October 1, 2013-March 31, 2016 as much as 225 patients.ResultAFB smear results in patients with type 2 DM with smear 3 + was 14 (17.28%), 2 + was 15 (18.52%), 1 + was 15 (18.52%) and negative (-) was 37 (45.68%). AFB smear results in patients without type 2 DM with smear 3 + was 3 (2.08%), 2 + was 6 (4.17%), 1 + was 19 (13.19%), negative (-) was 112 (77.78%) and have no sputum was 4 (2.78%). Number of adult pulmonary TB patients were 225 patients. Of the 225 patients, found 81 patients with type 2 DM and 144 patients without type 2 DM.ConclusionAFB smear positive found more in adult pulmonary TB patients with type 2 DM compared to TB patient without type 2 DM. It also found statistically significant between type 2 DM with the AFB smear results on adult pulmonary TB patients.
| S-EPMC5925956 | biostudies-literature
Project description:BackgroundTuberculosis (TB) is a chronic respiratory infectious disease caused by Mycobacterium tuberculosis, typically diagnosed through sputum smear microscopy for acid-fast bacilli (AFB) to assess the infectivity of TB.MethodsThis study enrolled 769 patients, including 641 patients from the First Affiliated Hospital of Guangxi Medical University as the training group, and 128 patients from Guangxi Hospital of the First Affiliated Hospital of Sun Yat-sen University as the validation group. Among the training cohort, 107 patients were AFB-positive, and 534 were AFB-negative. In the validation cohort, 24 were AFB-positive, and 104 were AFB-negative. Blood samples were collected and analyzed using machine learning (ML) methods to identify key factors for TB diagnosis.ResultsSeveral ML methods were compared, and support vector machine recursive feature elimination (SVM-RFE) was selected to construct a nomogram diagnostic model. The area under the curve (AUC) of the diagnostic model was 0.721 in the training cohort and 0.758 in the validation cohort. The model demonstrated clinical utility when the threshold was between 38% and 94%, with the NONE line above the ALL line in the decision curve analysis.ConclusionWe developed a diagnostic model using multiple ML methods to predict AFB results, achieving satisfactory diagnostic performance.
| S-EPMC11803159 | biostudies-literature
Project description:BackgroundDrug susceptibility testing for Mycobacterium tuberculosis (MTB) is difficult to perform in resource-limited settings where Acid Fast Bacilli (AFB) smears are commonly used for disease diagnosis and monitoring. We developed a simple method for extraction of MTB DNA from AFB smears for sequencing-based detection of mutations associated with resistance to all first and several second-line anti-tuberculosis drugs.MethodsWe isolated MTB DNA by boiling smear content in a Chelex solution, followed by column purification. We sequenced PCR-amplified segments of the rpoB, katG, embB, gyrA, gyrB, rpsL, and rrs genes, the inhA, eis, and pncA promoters and the entire pncA gene.ResultsWe tested our assay on 1,208 clinically obtained AFB smears from Ghana (n = 379), Kenya (n = 517), Uganda (n = 262), and Zambia (n = 50). Coverage depth varied by target and slide smear grade, ranging from 300X to 12000X on average. Coverage of ≥20X was obtained for all targets in 870 (72%) slides overall. Mono-resistance (5.9%), multi-drug resistance (1.8%), and poly-resistance (2.4%) mutation profiles were detected in 10% of slides overall, and in over 32% of retreatment and follow-up cases.ConclusionThis rapid AFB smear DNA-based method for determining drug resistance may be useful for the diagnosis and surveillance of drug-resistant tuberculosis.
| S-EPMC7209238 | biostudies-literature