scholarly journals A Comparision of Laboratory Diagnostic Methods of Tuberculosis and Aetiology of Suspected Cases of Pulmonary Tuberculosis

2015 ◽  
Vol 11 (2) ◽  
pp. 1-6
Author(s):  
Chandra Prakash Bhatt ◽  
B Timalsina ◽  
B Kutu ◽  
R Pradhan ◽  
B Maharjan ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Microscopic Examination ◽  
Fluorescent Microscopy ◽  
Public Health Problem ◽  
Diagnostic Methods ◽  
Fluorescent Staining ◽  
Acid Fast Bacilli ◽  
Direct Microscopic Examination ◽  
Culture Positive ◽  
Culture Negative

Introduction: Tuberculosis remains a worldwide public health problem despite the highly effective drugs and vaccines are available making tuberculosis a preventable and curable disease. The objective of this study was to compare the different laboratory diagnostic methods of tuberculosis and determine its prevalence. Methodology: Morning sputum samples were collected from suspected cases of pulmonary tuberculosis and preceded for Ziehl Neelsen staining, fluorescent staining (auramin-O) and mycobacterium culture in Lowenstein Jensen medium. Results: Total 78 suspected cases of pulmonary tuberculosis were included in this study among them 53 were male and 25 were female. Out of 78 cases, 46 cases were found to be culture positive. In culture positive cases (83%) were found to be M. tuberculosis and (17%) were found to be slow grower, fine colonies, AFB positive but niacin test negative (mycobacteria other than M. tuberculosis). In the direct microscopic examination by Ziehl Neelsen stained smear 26 samples were found to be acid fast bacilli and one sample was culture negative but acid fast bacilli positive. In fluorescent stained smear 34 samples were found to be positive for acid fast bacilli and 5 samples were culture negative but acid fast bacilli positive. Culture was accepted as gold standard, the sensitivity of direct microscopic examination was found 56.5% for Ziehl Neelsen staining and 73.9% for fluorescent staining respectively. Conclusion: In culture positive cases M. tuberculosis and mycobacteria other than M. tuberculosis was found to be 83% and 17% respectively, it was found higher in male than female. Fluorescent microscopy is superior to Ziehl Neelsen microscopy but gives more false positive result than Z-N staining. Combining of Ziehl Neelsen and fluorescent staining is better than fluorescent staining alone.DOI: http://dx.doi.org/10.3126/saarctb.v11i2.12427  SAARC J TUBER LUNG DIS HIV/AIDS, 2014;XI(2), page: 1-6

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

BMJ Open ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. e037913
Author(s):  
Mala George ◽  
Geert-Jan Dinant ◽  
Efrem Kentiba ◽  
Teklu Teshome ◽  
Abinet Teshome ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Cross Sectional Study ◽  
Clinical Suspicion ◽  
Secondary Outcome ◽  
Northern Ethiopia ◽  
Sectional Study ◽  
Cross Sectional ◽  
Smear Negative ◽  
Culture Positive ◽  
Culture Negative

ObjectivesTo evaluate the performance of the predictors in estimating the probability of pulmonary tuberculosis (PTB) when all versus only significant variables are combined into a decision model (1) among all clinical suspects and (2) among smear-negative cases based on the results of culture tests.DesignA cross-sectional study.SettingTwo public referral hospitals in Tigray, Ethiopia.ParticipantsA total of 426 consecutive adult patients admitted to the hospitals with clinical suspicion of PTB were screened by sputum smear microscopy and chest radiograph (chest X-ray (CXR)) in accordance with the Ethiopian guidelines of the National Tuberculosis and Leprosy Program. Discontinuation of antituberculosis therapy in the past 3 months, unproductive cough, HIV positivity and unwillingness to give written informed consent were the basis of exclusion from the study.Primary and secondary outcome measuresA total of 354 patients were included in the final analysis, while 72 patients were excluded because culture tests were not done.ResultsThe strongest predictive variables of culture-positive PTB among patients with clinical suspicion were a positive smear test (OR 172; 95% CI 23.23 to 1273.54) and having CXR lesions compatible with PTB (OR 10.401; 95% CI 5.862 to 18.454). The regression model had a good predictive performance for identifying culture-positive PTB among patients with clinical suspicion (area under the curve (AUC) 0.84), but it was rather poor in patients with a negative smear result (AUC 0.64). Combining all the predictors in the model compared with only the independent significant variables did not really improve its performance to identify culture-positive (AUC 0.84–0.87) and culture-negative (AUC 0.64–0.69) PTB.ConclusionsOur finding suggests that predictive models based on clinical variables will not be useful to discriminate patients with culture-negative PTB from patients with culture-positive PTB among patients with smear-negative cases.

scholarly journals Comparison of Acid Fast Bacilli Smear and Culture for the Diagnosis of Extra-Pulmonary Tuberculosis

2004 ◽  
Vol 43 (155) ◽  
Author(s):  
Basista Rijal ◽  
P Ghimire ◽  
N R Tuladhar
Keyword(s):  
Lymph Node ◽  
Pulmonary Tuberculosis ◽  
Pericardial Fluid ◽  
The Body ◽  
Diagnostic Methods ◽  
Isolation Rate ◽  
Extra Pulmonary Tuberculosis ◽  
Acid Fast Bacilli ◽  
New Methods ◽  
Extra Pulmonary

The study was conducted with the objectives to compare the Acid Fast Bacilli (AFB) staining and Culture for the diagnosis of extra-pulmonary tuberculosis and to find out the burden of extra-pulmonary tuberculosis from the different site of the body in suspected TB patients. The standard Ziehl-Neelsen Technique was done for AFB staining and culture was done in Ogawa Medium. Of the 292 extra-pulmonary samples examined by AFB smear only 2(0.7%) were positive and of the 1058 extra-pulmonary samples cultured 20 (1.9%) were positive. The isolation rate for extra-pulmonary samples was three fold higher in culture in comparison to AFB Smear. The confirmation rate of extra-pulmonary tuberculosis was approximately 1/ 8th of the pulmonary tuberculosis by conventional bacteriological diagnostic methods. Of the extra-pulmonary tuberculosis renal, endometrial or pelvic and cold abscess were common in this study. M.tuberculosis was also isolated from peritoneal fluid, pericardial fluid, Synovial fluid, lymph node and cerebro spinal fluids only by culture. In conclusion, the standard AFB culture has significant role for diagnosis of extra-pulmonary tuberculosis, even though the conventional bacteriological technique could diagnose very low number of extra-pulmonary tuberculosis. The new methods of diagnosis should be considered to confirm more extra- pulmonary  tuberculosis.Key Words: Extra-pulmonary tuberculosis, AFB Smear, Culture, Diagnosis, Nepal.

scholarly journals Direct Detection of Shigella in Stool Specimens by Use of a Metagenomic Approach

2017 ◽  
Vol 56 (2) ◽  
Author(s):  
Jie Liu ◽  
Mathieu Almeida ◽  
Furqan Kabir ◽  
Sadia Shakoor ◽  
Shahida Qureshi ◽  
...  
Keyword(s):  
Direct Detection ◽  
Positive Culture ◽  
Accurate Method ◽  
Diagnostic Methods ◽  
Metagenomic Sequencing ◽  
Illumina Hiseq ◽  
Content Type ◽  
Sequence Composition ◽  
Culture Positive ◽  
Culture Negative

ABSTRACTThe underestimation ofShigellaspecies as a cause of childhood diarrhea disease has become increasingly apparent with quantitative PCR (qPCR)-based diagnostic methods versus culture. We sought to confirm qPCR-based detection ofShigellavia a metagenomics approach. Three groups of samples were selected from diarrheal cases from the Global Enteric Multicenter Study: nineShigellaculture-positive and qPCR-positive (culture+qPCR+) samples, nine culture-negative but qPCR-positive (culture−qPCR+) samples, and nine culture-negative and qPCR-negative (culture−qPCR−) samples. Fecal DNA was sequenced using paired-end Illumina HiSeq, whereby 3.26 × 108± 5.6 × 107high-quality reads were generated for each sample. We used Kraken software to compare the read counts specific to “Shigella” among the three groups. The proportions ofShigella-specific nonhuman sequence reads between culture+qPCR+(0.65 ± 0.42%) and culture−qPCR+(0.55 ± 0.31%) samples were similar (Mann-Whitney U test,P= 0.627) and distinct from the culture−qPCR−group (0.17 ± 0.15%,P< 0.05). The read counts of sequences previously targeted byShigella/enteroinvasiveEscherichia coli(EIEC) qPCR assays, namely,ipaH,virA,virG,ial,ShET2, andipaH3, were also similar between the culture+qPCR+and culture−qPCR+groups and distinct from the culture−qPCR−groups (P< 0.001). Kraken performed well versus other methods: its precision and recall ofShigellawere excellent at the genus level but variable at the species level. In summary, metagenomic sequencing indicates thatShigella/EIEC qPCR-positive samples are similar to those ofShigellaculture-positive samples inShigellasequence composition, thus supporting qPCR as an accurate method for detectingShigella.

scholarly journals Comparison between ziehl-neelsen staining and fluorescent staining of sputum samples to detect acid fast bacilli in suspected case of pulmonary tuberculosis at tertiary care hospital, Amreli, Gujarat

2021 ◽  
Vol 8 (4) ◽  
pp. 302-307
Author(s):  
Hetvi Chawda ◽  
Chandani Surani ◽  
Sanjeev Kumar ◽  
Meghana Chauhan ◽  
Ashok Kumar Ramanuj ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Tertiary Care ◽  
Early Morning ◽  
Causative Organism ◽  
Sputum Smear ◽  
Suspected Case ◽  
Care Hospital ◽  
Fluorescent Staining ◽  
Acid Fast Bacilli ◽  
Fluorescent Stain

In India, Tuberculosis (TB) is one of the major community health problems.Pulmonary tuberculosis (PTB) is a respiratory disease. Causative organism for this is acid fast bacilli known as . It is the most ordinary disease affecting the lower socio-economic class in developing countries. Microbiological diagnosis is the heart for the effective treatment of pulmonary TB (PTB). The look forrapid and efficient method has resulted in several staining techniques. Objective of the study was to compare the results of ZN stain (RNTCP) with fluorescent stain by use of microscopy. The study was carried out in Microbiology Department, SMCGH, Amreli. 350 sputum samples (Spot and early morning sample) collected from 175 suspected case of the pulmonary tuberculosis. All 350 samples were processed by ZN stain and Fluorescent stain to detect acid fast bacilli. By use of microscope, the results of the stained smears were given according to RNTCP guideline.Out of 350 sputum smears, 52 (14.85%) and 61 (17.4%) were positive by ZN and FM staining respectively. Males are predominantly affected than females. Majority of the patients were in age above 50 years. Early morning samples were more reliable than spot samples for detection of acid fast bacilli for ZN stain, but not for fluorescent stain.Fluorescent staining with LED microscopy was more efficient than ZN staining for detection of acid fast bacilli from sputum smear.

scholarly journals Diagnosis of Cutaneous Leishmaniasis in Colombia: the Sampling Site within Lesions Influences the Sensitivity of Parasitologic Diagnosis

2000 ◽  
Vol 38 (10) ◽  
pp. 3768-3773 ◽  
Author(s):  
José Robinson Ramírez ◽  
Sonia Agudelo ◽  
Carlos Muskus ◽  
Juan Fernando Alzate ◽  
Christof Berberich ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Microscopic Examination ◽  
Sampling Site ◽  
Parasite Load ◽  
Diagnostic Methods ◽  
Active Margins ◽  
Direct Microscopic Examination ◽  
Chronic Ulcers ◽  
Pcr Method ◽  
Higher Sensitivity

Parasitologic confirmation of cutaneous leishmaniasis is obligatory before chemotherapy can be considered. Direct microscopic examination of scrapings taken from indurated borders of ulcers has been routinely used as primary method of diagnosis. In this report we compared the sensitivity of examination of dermal scrapings taken from the bottoms of ulcers (BDS) with that of dermal scrapings taken from indurated active margins of lesions (MDS) in a total of 115 patients. The sensitivities of the microscopic examination were 90.4 and 78.3% for BDS and MDS samples, respectively. When the PCR method was used with a group of 40 patients, we also observed a higher sensitivity when BDS samples were examined (80.8% in BDS samples versus 57.7% in MDS samples). The improvement of the diagnostic sensitivity in the BDS samples appears to be related to the higher parasite load and more easily detectable morphology of amastigotes in the centers of the ulcers. Other parasitologic diagnostic methods, such as culture and histopathologic examination of biopsies, are less sensitive (67.5 and 64.3%, respectively). Aspirate culture, however, was shown to be the most sensitive method for the diagnosis of patients with chronic ulcers. When microscopic examinations of both MDS and BDS samples are combined, the sensitivity of diagnosis may rise up to 94%. We therefore recommend this method as a primary routine procedure for diagnosis of cutaneous leishmaniasis.

scholarly journals Detection of Mycobacterium tuberculosis complex organisms in the stools of patients with pulmonary tuberculosis

Microbiology ◽  
2009 ◽  
Vol 155 (7) ◽  
pp. 2384-2389 ◽  
Author(s):  
Amel El Khéchine ◽  
Mireille Henry ◽  
Didier Raoult ◽  
Michel Drancourt
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Pulmonary Tuberculosis ◽  
Respiratory Tract ◽  
Real Time ◽  
Microscopic Examination ◽  
Real Time Pcr ◽  
Correct Diagnosis ◽  
Signs And Symptoms ◽  
Laboratory Diagnosis ◽  
Acid Fast Bacilli

The laboratory diagnosis of pulmonary tuberculosis mainly relies on the detection of Mycobacterium tuberculosis complex (MTC) organisms in the sputum. In patients who do not give sputum, alternative respiratory tract specimens can be obtained only by invasive procedures. Based on the known survival of MTC organisms in the gastric fluid, we hypothesized that swallowed MTC organisms would be detectable in stool samples. We compared the presence of MTC organisms in respiratory tract specimens and stool specimens collected in parallel from the same patients. MTC was detected in cultures grown on egg-based medium after appropriate decontamination, by microscopic examination after Ziehl–Neelsen staining and by real-time PCR detection of IS6110 using internal controls. A case of pulmonary tuberculosis was defined by the presence of (i) clinical and radiological signs and symptoms suggestive of pulmonary tuberculosis, and (ii) culture of MTC organisms from at least one respiratory tract specimen or (iii) the presence of acid-fast bacilli in the sputum that were subsequently identified as MTC organisms by real-time PCR. The observation of 134 patients suspected to be suffering pulmonary tuberculosis led to the identification of 24 cases and 110 non-infected control patients. Cases and controls did not significantly differ with respect to sex but cases were significantly younger than controls. The sensitivity/specificity was 37.5 %/100 % for the microscopic examination of stools, 54.2 %/100 % for culturing and 100 %/97.3 % for real-time PCR. The positive predicted value was 100 %, 100 % and 88.9 %, respectively, and the negative predicted value was 88 %, 90.9 % and 100 %, respectively. In four patients, a stool specimen initially yielded the correct diagnosis of pulmonary tuberculosis before evaluation of the respiratory tract specimen confirmed the diagnosis. These data indicate that stools could be used in conjunction with sputum testing or as an alternative specimen upon which to base the diagnosis of pulmonary tuberculosis by molecular identification of acid-fast bacilli and culture. This non-invasive alternative procedure is of particular interest for patients who cannot expectorate.

scholarly journals A comparative study of fluorescent microscopy with Ziehl-Neelsen staining and culture for the diagnosis of pulmonary tuberculosis

1970 ◽  
Vol 7 (3) ◽  
pp. 226-230 ◽  
Author(s):  
S Laifangbam ◽  
HL Singh ◽  
NB Singh ◽  
KM Devi ◽  
NT Singh
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Fluorescence Microscopy ◽  
Pulmonary Tuberculosis ◽  
Fluorescent Microscopy ◽  
False Negative ◽  
Diagnostic Methods ◽  
Case Detection ◽  
Detection Rates ◽  
Auramine O ◽  
The Difference

Background: For developing countries with a large number of cases and financial constraints, evaluation of rapid and inexpensive diagnostic methods has great importance. The bacilli in the sputum can be detected microscopically by ZN stain and fluorochrome stain. Objectives : To study the efficacy of fluorescence microscopy in the diagnosis of pulmonary tuberculosis in comparison to Ziehl-Neelsen staining and culture of sputum samples from patients suspected of pulmonary tuberculosis. Materials and methods : 306 sputum samples collected from 102 patients suspected of pulmonary tuberculosis were processed by the Petroff's method, and subjected to Ziehl-Neelsen staining (ZN), fluorescent Auramine-O staining (AO) and culture on modified Lowenstein-Jensen media (gold standard) for detection of Mycobacterium tuberculosis. Positive smears were graded according to Forbes BA et al, and culture isolates were biochemically tested for confirmation of species. Results : Out of 102 patients, 44.1%, 71.6% and 70% were found positive by ZN, AO and culture respectively. AO was found to be superior to ZN on several aspects. The difference in their case detection rates was statistically significant (χ2 = 24.93, p < 0.001). AO was also able to detect more pauci-bacillary cases than ZN. There was more agreement between culture and fluorescence microscopy (95.1%) than with ZN microscopy (69.6%). The percentage of false negative by AO staining was only 2.78% which was in sharp contrast to that of ZN (40.27%). Conclusion: The better case detection rates of AO over ZN were comparable to those found by several studies. Since screening was done under lower power of magnification (400x), fluorescence microscopy has been found to be less time consuming as compared to ZN method (1000x) in the diagnosis of tuberculosis. The tubercle bacilli stood out as bright objects against a dark background in fluorescence microscopy which makes them easily identifiable hence causing less eye-strain. The efficacy of fluorescence microscopy proved to be much higher than conventional light microscopy and comparable to that of culture. Key words: Ziehl-Neelsen staining; Mycobacterium tuberculosis; Auramine-O DOI: 10.3126/kumj.v7i3.2728 Kathmandu University Medical Journal (2009) Vol.7, No.3 Issue 27, 226-230

scholarly journals Factors Associated With Sputum Culture-Negative vs Culture-Positive Diagnosis of Pulmonary Tuberculosis

2019 ◽  
Vol 2 (2) ◽  
pp. e187617 ◽  
Author(s):  
Minh-Vu H. Nguyen ◽  
Natalie S. Levy ◽  
Shama D. Ahuja ◽  
Lisa Trieu ◽  
Douglas C. Proops ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Sputum Culture ◽  
Positive Diagnosis ◽  
Factors Associated ◽  
Culture Positive ◽  
Culture Negative

Score for pulmonary tuberculosis in patients with clinical presumption of tuberculosis in a low-prevalence area

2017 ◽  
Vol 21 (12) ◽  
pp. 1272-1279 ◽  
Author(s):  
T. Delory ◽  
H. Ferrand ◽  
N. Grall ◽  
E. Casalino ◽  
M. Lafarge ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Conditional Logistic Regression ◽  
Internal Validity ◽  
Nucleic Acid Amplification ◽  
Smear Negative ◽  
Low Incidence ◽  
Low Prevalence ◽  
Culture Positive ◽  
Culture Negative ◽  
Control Study

OBJECTIVES: To develop a diagnostic predictive model for the identification of patients with presumptive pulmonary tuberculosis (PTB) at high risk for active disease and those requiring nucleic acid amplification (NAAT) testing and/or preventive respiratory isolation in low-incidence, high-income countries.DESIGN: A 1:1 case-control study was conducted in consecutive immunocompetent patients with presumed PTB hospitalised between 2009 and 2012 in Paris, France. Cases were defined as individuals with culture-confirmed PTB, regardless of smear result. Those with presumed PTB and three smear- and culture-negative samples were selected as controls. A score was derived using conditional logistic regression. Internal validity of the score was assessed using the bootstrap method.RESULTS: A total of 354 patients were included in the analysis (177 cases, 177 controls). Among the 177 cases, 74 (42%) were smear-negative but culture-positive. Factors independently associated with PTB were age <50 years (adjusted OR [aOR] 4.7, 95%CI 1.8–12), diabetes (aOR 3.2, 95%CI 1.1–9.8), absence of cough with or without sputum (aOR 3.7, 95%CI 1.7–8.3), fever >15 days (aOR 3.5, 95%CI 1.3–9.5), apical infiltration without cavity (aOR 3.4, 95%CI 1.4–8.5) and cavitation or miliary pattern (aOR 19.7, 95%CI 7.6–51.1). Score C-index was 0.84 (95%CI 0.79–0.88). Calibration for the overall population (P = 0.770) and in smear-negative patients (P = 0.980) was appropriate. A score of 3.3 had 90% sensitivity, 50% specificity and 79% (IQR 28–95) median probability of PTB.CONCLUSIONS: This score could be used to build an algorithm to determine the need for respiratory isolation and/or NAAT use in PTB disease.

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