This study was aimed to investigate the diagnostic value of fiberoptic bronchoscopy (FOB) with chest high-resolution computed tomography (HRCT) for the rapid diagnosis of active pulmonary tuberculosis (PTB) in patients suspected of PTB but found to have a negative sputum acid-fast bacilli (AFB) smear.
We evaluated the diagnostic accuracy of results from FOB and HRCT in 126 patients at Gangnam Severance Hospital (Seoul, Korea) who were suspected of having PTB.
Of 126 patients who had negative sputum AFB smears but were suspected of having PTB, 54 patients were confirmed as having active PTB. Hemoptysis was negatively correlated with active PTB. Tree-in-bud appearance on HRCT was significantly associated with active PTB. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FOB alone was 75.9%, 97.2%, 95.3%, and 84.3%, respectively, for the rapid diagnosis of active PTB. The combination of FOB and HRCT improved the sensitivity to 96.3% and the NPV to 96.2%.
FOB is a useful tool in the rapid diagnosis of active PTB with a high sensitivity, specificity, PPV and NPV in sputum smear-negative PTB-suspected patients. HRCT improves the sensitivity of FOB when used in combination with FOB in sputum smear-negative patients suspected of having PTB.
Diagnosis of sputum/smear-negative pulmonary tuberculosis patients can be both challenging and time consuming with many patients being put on empirical anti-tubercular treatment. Fibreoptic bronchoscopy may provide a confirmative and early diagnosis in such patients.
To assess the role of fibreoptic bronchoscopy in the diagnosis of sputum /smear-negative pulmonary tuberculosis.
Materials and Methods:
The study was conducted on 75 suspected sputum / smear-negative pulmonary tuberculosis cases attending Pulmonary Medicine Department of Mamata Medical College and Hospital, Khammam, AP. Fibreoptic bronchoscopy was performed; culture of sputum and bronchial washings for Mycobacterium tuberculosis was done by BACTEC method.
A final diagnosis of sputum /smear-negative pulmonary tuberculosis was made in 60 patients. Bronchial washings smear for acid-fast bacilli (AFB) was positive in 21 patients while culture of bronchial washings was positive in 39 patients. In 29 patients, smear or culture of bronchial washing alone contributed to the final diagnosis. Total yield of bronchoscopy in diagnosis of sputum smear negative pulmonary tuberculosis was 83.33% (50/60); bronchoscopy was the only diagnostic method in 66% cases (40/60) with bronchial washings being the only diagnostic method in 48.33%. Bronchial washings smear for AFB and histopathological evidence of caseating granuloma made immediate diagnosis possible in 48.33% (29/60) patients.
Our study suggests that fibreoptic bronchoscopy can provide excellent material for diagnosis of suspected cases of Pulmonary Tuberculosis in whom smears of expectorated sputum do not reveal mycobacteria.
Bronchial washings; fibreoptic bronchoscopy; pulmonary tuberculosis; sputum smear negative
About 30 to 50 % of pulmonary tuberculosis patients have sputum report negative for acid fast bacilli or present with no expectoration. A lot of research is going on to find methods to establish early and accurate diagnosis of pulmonary tuberculosis (PTB) as institutions of early treatment can have significant effects on morbidity and mortality of patients and also the development of MDR–TB. Samples other than sputum play an important role in the diagnosis of disease in such patients.
To assess the significance of bronchoalveolar lavage samples and fiberoptic bronchoscopy (FOB) in the early diagnosis of occult sputum smear negative pulmonary tuberculosis.
Settings and Design:
Study was conducted in a tertiary care hospital. FOB was performed in patients with three consecutive sputum smear negative acid fast bacilli to obtain bronchoalveolar lavage (BAL) samples. Written informed consent was obtained from these patients.
Materials and Methods:
BAL samples were subjected to Z-N staining and culture on L-J slopes for acid fast bacilli. Sputum samples from the same patients were also cultured.
BAL samples were positive in 82.2% of sputum smear negative samples. Culture positivity of BAL samples was 90.9% as compared to sputum culture positivity which was 26.4%. Overall diagnosis could be established in 86.6% of patients with the help of fiber optic bronchoscopy.
BAL samples are very useful in early sputum smear negative pulmonary tuberculosis and FOB can play an important role in diagnosis of lower respiratory tract infections with minimal complications in hands of an expert.
Bronchoalveolar lavage; fiber optic bronchoscopy; occult tuberculosis; lower respiratory tract infection; tuberculosis
A total of 356 patients were subjected to fibreoptic bronchoscopy from September 1989 to June 1991 to exclude bronchial carcinoma. Bronchial biopsy, bronchial brush smears and bronchial wash were obtained. Bronchial wash was examined for acid fast bacilli (AFB) compatible with Mycobacterium tuberculosis. The total number diagnosed as pulmonary tuberculosis by fibreoptic bronchoscopy was 21(5.8%). The sputum smears were negative for AFB in all these patients. Previous studies have shown the importance of fibreoptic bronchoscopy in suspected cases of tuberculosis where the sputum smear is negative. This study is further evidence of the importance of routine examination of bronchial wash for AFB in all cases undergoing fibreoptic bronchoscopy to detect atypical cases of pulmonary tuberculosis.
Rationale: The rapid diagnosis of pulmonary tuberculosis (TB) is difficult when acid fast bacilli (AFB) cannot be detected in sputum smears.
Objectives: Following a proof of principle study, we examined in routine clinical practice whether individuals with sputum AFB smear-negative TB can be discriminated from those with latent TB infection by local immunodiagnosis with a Mycobacterium tuberculosis–specific enzyme-linked immunospot (ELISpot) assay.
Methods: Subjects suspected of having active TB who were unable to produce sputum or with AFB-negative sputum smears were prospectively enrolled at Tuberculosis Network European Trialsgroup centers in Europe. ELISpot with early-secretory-antigenic-target–6 and culture-filtrate-protein–10 peptides was performed on peripheral blood mononuclear cells (PBMCs) and bronchoalveolar lavage mononuclear cells (BALMCs). M. tuberculosis–specific nucleic acid amplification (NAAT) was performed on bronchoalveolar lavage fluid.
Measurements and Main Results: Seventy-one of 347 (20.4%) patients had active TB. Out of 276 patients who had an alternative diagnosis, 127 (46.0%) were considered to be latently infected with M. tuberculosis by a positive PBMC ELISpot result. The sensitivity and specificity of BALMC ELISpot for the diagnosis of active pulmonary TB were 91 and 80%, respectively. The BALMC ELISpot (diagnostic odds ratio [OR], 40.4) was superior to PBMC ELISpot (OR, 10.0), tuberculin skin test (OR, 7.8), and M. tuberculosis specific NAAT (OR, 12.4) to diagnose sputum AFB smear-negative TB. In contrast to PBMC ELISpot and tuberculin skin test, the BALMC ELISpot was not influenced by previous history of TB.
Conclusions: Bronchoalveolar lavage ELISpot is an important advancement to rapidly distinguish sputum AFB smear-negative TB from latent TB infection in routine clinical practice.
Background. Tuberculosis (TB) disease diagnosis in Vietnam relies on symptom screening, chest radiography (CXR), and acid fast bacilli (AFB) sputum smear which have a poor sensitivity in HIV patients. We evaluated the performance of clinical algorithms in screening and diagnosing AFB smear-negative TB in HIV patients. Methods. We enrolled 399 HIV-positive patients seeking care at a HIV clinic in Ho Chi Minh City (HCMC), Vietnam. Participants' demographics, medical history, common TB symptoms, CXR, and laboratory tests were collected. Results. Of 399 HIV patients, 390 had initial AFB-negative smears and 22/390 patients had positive cultures. Symptom screening missed 54% (12/22) of smear-negative pulmonary TB (PTB) cases. Multivariate analysis found CD4+ cell level and CXR were significant PTB predictors. An algorithm combining four TB symptoms and TST presented a high sensitivity (100%), but poorly specific (24%) diagnostic performance for smear-negative PTB. Conclusion. Up to 54% of PTB cases in the HIV-infected population may be missed in the routine screening and diagnostic procedures used in Vietnam. Symptom screening was a poor overall diagnostic measure in detecting smear-negative TB in HIV patients. Our study results suggest that routine sputum cultures should be implemented to achieve a more accurate diagnosis of TB in HIV patients.
BACKGROUND: Pulmonary tuberculosis can produce unusual radiographic appearances and negative results of sputum and bronchoscopic examinations are common. This study assessed the value of ultrasound guided aspiration biopsy in the diagnosis of pulmonary tuberculosis with unusual radiographic appearances. METHODS: Thirteen patients, ultimately diagnosed as having tuberculosis, underwent a chest ultrasonographic examination between June 1984 and August 1991. All had sputum available for examination and nine were also examined by bronchoscopy. Ten patients who had a negative sputum smear and negative bronchoscopic brushing smears underwent ultrasound guided aspiration or biopsy. Percutaneous aspiration was performed with a 22 gauge needle. If the smear did not reveal acid fast bacilli, a biopsy sample was taken with a 16 gauge Tru-cut needle to obtain a histological diagnosis. RESULTS: The ultrasonographic examination delineated the more complex nature of the lesions better than the chest radiograph. Ultrasound guided aspiration biopsy provided the diagnosis in nine of 10 patients, while the sputum smear and culture provided diagnosis in five of 13, and bronchoscopy in four of nine. In terms of rapid diagnosis, ultrasound guided aspiration biopsy gave the diagnosis in eight of 10 cases. No patient developed a major complication. CONCLUSION: Ultrasonography can direct the needle to the most suitable part of a lesion to obtain the relevant specimens. The diagnostic yield is high and the procedure is relatively safe. It is especially helpful in patients with negative results of sputum and bronchoscopic examinations.
Nowadays, endobronchial tuberculosis is of rare occurrence. This article presents three such cases. All of them presented as unresolved pneumonia with collapse-consolidation in chest X-ray. All the three patients were sputum smear negative for acid fast bacilli. Diagnosis was possible only with fiberoptic bronchoscopy and bronchial biopsy.
Endobronchial tuberculosis; fibreoptic bronchoscopy; unresolved pneumonia
Direct smear examination with Ziehl-Neelsen (ZN) staining for the diagnosis of pulmonary tuberculosis (PTB) is cheap and easy to use, but its low sensitivity is a major drawback, particularly in HIV seropositive patients. As such, new tools for laboratory diagnosis are urgently needed to improve the case detection rate, especially in regions with a high prevalence of TB and HIV.
To evaluate the performance of two in house PCR (Polymerase Chain Reaction): PCR dot-blot methodology (PCR dot-blot) and PCR agarose gel electrophoresis (PCR-AG) for the diagnosis of Pulmonary Tuberculosis (PTB) in HIV seropositive and HIV seronegative patients.
A prospective study was conducted (from May 2003 to May 2004) in a TB/HIV reference hospital. Sputum specimens from 277 PTB suspects were tested by Acid Fast Bacilli (AFB) smear, Culture and in house PCR assays (PCR dot-blot and PCR-AG) and their performances evaluated. Positive cultures combined with the definition of clinical pulmonary TB were employed as the gold standard.
The overall prevalence of PTB was 46% (128/277); in HIV+, prevalence was 54.0% (40/74). The sensitivity and specificity of PCR dot-blot were 74% (CI 95%; 66.1%-81.2%) and 85% (CI 95%; 78.8%-90.3%); and of PCR-AG were 43% (CI 95%; 34.5%-51.6%) and 76% (CI 95%; 69.2%-82.8%), respectively. For HIV seropositive and HIV seronegative samples, sensitivities of PCR dot-blot (72% vs 75%; p = 0.46) and PCR-AG (42% vs 43%; p = 0.54) were similar. Among HIV seronegative patients and PTB suspects, ROC analysis presented the following values for the AFB smear (0.837), Culture (0.926), PCR dot-blot (0.801) and PCR-AG (0.599). In HIV seropositive patients, these area values were (0.713), (0.900), (0.789) and (0.595), respectively.
Results of this study demonstrate that the in house PCR dot blot may be an improvement for ruling out PTB diagnosis in PTB suspects assisted at hospitals with a high prevalence of TB/HIV.
Background and objectives
The frequency, aetiologies, and outcomes of normal chest radiographs (CXRs) among HIV-seropositive patients with suspected pulmonary tuberculosis (TB) have been infrequently described.
Consecutive HIV-seropositive adults hospitalized for cough of ≥ 2 weeks duration at Mulago Hospital (Kampala, Uganda), between September 2007 and July 2008, were enrolled. Baseline CXRs were obtained on admission. Patients with sputum smears that were negative for acid-fast bacilli (AFB) were referred for bronchoscopy with bronchoalveolar lavage (BAL). BAL fluid was examined for mycobacteria, Pneumocystis jirovecii, and other fungi. Patients were followed for two months after enrolment.
Of the 334 patients, 54 (16%) had normal CXRs. These patients were younger (median age 30 vs. 34 years, P=0.002), had lower counts of CD4+ T lymphocytes (median 13 vs. 57 cells/μL, P<0.001), and were less likely to be smear positive for AFB (17% vs. 39%, P=0.002) than those with abnormal CXRs. Pulmonary TB was the most frequent diagnosis (44%) among those with normal CXRs, followed by unknown diagnoses, pulmonary aspergillosis, and pulmonary cryptococcosis. The frequency of normal CXRs was 12% among pulmonary TB patients. There was a trend towards increased two-month mortality among patients with normal CXRs compared to those with abnormal CXRs (40% vs. 29%, P=0.15).
Normal CXR findings were common among HIV-seropositive patients with suspected TB, especially those who were young, those with low CD4+ T cell counts, and those with sputum smears that were negative for AFB. Mortality was high among those with normal CXRs. Normal CXR findings should not preclude further diagnostic evaluation in this population.
clinical epidemiology; critical care medicine; immunodeficiency; radiology and other imaging; tuberculosis
Diagnostic options for pulmonary tuberculosis in resource-poor settings are commonly limited to smear microscopy. We investigated whether bleach concentration by sedimentation and sputum cytology analysis (SCA) increased the positivity rate of smear microscopy for smear-positive tuberculosis.
We did a prospective diagnostic study in a Médecins Sans Frontières-supported hospital in Mindouli, Republic of Congo. Three sputum samples were obtained from 280 consecutive pulmonary tuberculosis suspects, and were processed according to WHO guidelines for direct smear microscopy. The remainder of each sputum sample was homogenised with 2.6% bleach, sedimented overnight, smeared, and examined blinded to the direct smear result for acid-fast bacilli (AFB). All direct smears were assessed for quality by SCA. If a patient produced fewer than three good-quality sputum samples, further samples were requested. Sediment smear examination was performed independently of SCA result on the corresponding direct smear. Positivity rates were compared using McNemar's test.
Excluding SCA, 43.2% of all patients were diagnosed as positive on direct microscopy of up to three samples. 47.9% were diagnosed on sediment microscopy, with 48.2% being diagnosed on direct microscopy, sediment microscopy, or both. The positivity rate increased from 43.2% to 47.9% with a case definition of one positive smear (≥1 AFB/100 high power fields) of three, and from 42.1% to 43.9% with two positive smears. SCA resulted in 87.9% of patients producing at least two good-quality sputum samples, with 75.7% producing three or more. Using a case definition of one positive smear, the incremental yield of bleach sedimentation was 14/121, or 11.6% (95% CI 6.5-18.6, p = 0.001) and in combination with SCA was 15/121, or 12.4% (95% CI 7.1-19.6, p = 0.002). Incremental yields with two positive smears were 5/118, or 4.2% (95% CI 1.4-9.6, p = 0.062) and 7/118, or 5.9% (95% CI 2.4-11.8, p = 0.016), respectively.
The combination of bleach sedimentation and SCA resulted in significantly increased microscopy positivity rates with a case definition of either one or two positive smears. Implementation of bleach sedimentation led to a significant increase in the diagnosis of smear-positive patients. Implementation of SCA did not result in significantly increased diagnosis of tuberculosis, but did result in improved sample quality. Requesting extra sputum samples based on SCA results, combined with bleach sedimentation, could significantly increase the detection of smear-positive patients if routinely implemented in resource-limited settings where gold standard techniques are not available. We recommend that a pilot phase is undertaken before routine implementation to determine the impact in a particular context.
Tuberculosis is one of the most prominent health problems in the world, causing 1.75 million deaths each year. Rapid clinical diagnosis is important in patients who have co-morbidities such as Human Immunodeficiency Virus (HIV) infection. Direct microscopy has low sensitivity and culture takes 3 to 6 weeks [1-3]. Therefore, new tools for TB diagnosis are necessary, especially in health settings with a high prevalence of HIV/TB co-infection.
In a public reference TB/HIV hospital in Brazil, we compared the cost-effectiveness of diagnostic strategies for diagnosis of pulmonary TB: Acid fast bacilli smear microscopy by Ziehl-Neelsen staining (AFB smear) plus culture and AFB smear plus colorimetric test (PCR dot-blot).
From May 2003 to May 2004, sputum was collected consecutively from PTB suspects attending the Parthenon Reference Hospital. Sputum samples were examined by AFB smear, culture, and PCR dot-blot. The gold standard was a positive culture combined with the definition of clinical PTB. Cost analysis included health services and patient costs.
The AFB smear plus PCR dot-blot require the lowest laboratory investment for equipment (US$ 20,000). The total screening costs are 3.8 times for AFB smear plus culture versus for AFB smear plus PCR dot blot costs (US$ 5,635,760 versus US$ 1,498, 660). Costs per correctly diagnosed case were US$ 50,773 and US$ 13,749 for AFB smear plus culture and AFB smear plus PCR dot-blot, respectively. AFB smear plus PCR dot-blot was more cost-effective than AFB smear plus culture, when the cost of treating all correctly diagnosed cases was considered. The cost of returning patients, which are not treated due to a negative result, to the health service, was higher in AFB smear plus culture than for AFB smear plus PCR dot-blot, US$ 374,778,045 and US$ 110,849,055, respectively.
AFB smear associated with PCR dot-blot associated has the potential to be a cost-effective tool in the fight against PTB for patients attended in the TB/HIV reference hospital.
There are number of patients who are unable to expectorate sputum specimens. In this study, we used gastric lavage (GL) test for diagnosis of tuberculosis (TB) in patients who were unable to produce sputum.
Materials and Methods:
Patients who were unable to produce sputum specimens were included in the study to confirm TB disease. Gastric lavage sampling was performed and sent for acid fast bacillus smear and culture under special laboratory conditions and sterilized methods. Further bronchoscopy for broncho-alveolar lavage was done on patients with negative GL smear results. Drug susceptibility tests were performed on 48 GL culture positive cases.
Eighty-five patients were included in the study; who were hospitalized at our referral center for suspected TB. GL smears were reported to be positive in 37 cases (66.07%) and culture in 85.7%. The total number of smear and culture-positive cases in this study was 48 (85.7%). Forty cases (87%) of drug-sensitive, 1 case (2.2%) of isoniazid and rifampin-resistant TB (multi-drug resistant; MDR), and 5 cases of resistant to one drug were detected. There have not been observed any complications after the GL method.
It seems that regarding the high number of positive GL cultures (85.7%), GL can be effective for diagnosis of patients who have suspicious tuberculosis symptoms and are unable to produce sputum especially in resource limited areas.
Acid fast bacillus; Broncho-alveolar lavage; Gastric lavage; Isoniazid; Rifampin; Tuberculosis
Sputum smears for acid-fast bacilli (AFB) are the primary methods for diagnosis of tuberculosis (TB) in many countries. The tuberculin skin test (TST) is the primary method for diagnosis of latent TB infection (LTBI) worldwide. The poor sensitivity of the former and the poor specificity of the latter warrant the development of new tests and strategies to enhance diagnostic capabilities. We evaluated the sensitivity of an “in-tube” gamma interferon release assay (IGRA) using TB-specific antigens in comparison to the TST and the sputum smear for AFB in TB cases in South Africa. The sensitivity of the IGRA for TB was considered a surrogate of sensitivity in LTBI. Among 154 patients with a positive culture for Mycobacterium tuberculosis, the sensitivity of the IGRA for the diagnosis of TB varied by clinical subgroup from 64% to 82%, that of the TST varied from 85% to 94%, and that of two sputum smears for AFB varied from 35% to 53%. The sensitivity of the IGRA in human immunodeficiency virus (HIV)-infected TB cases was 81%. HIV-infected TB patients were significantly more likely to have indeterminate IGRA results and produced quantitatively less gamma interferon in response to TB-specific antigens than HIV-negative TB patients. The overall sensitivity of the TST in all TB cases was higher than that of the IGRA (90% versus 76%, respectively). The combined sensitivities of the TST plus IGRA and TST plus a single sputum smear were 96% and 93%, respectively. The TST combined with IGRA or with a single sputum smear may have a role in excluding the diagnosis of TB in some settings.
Clinical suspects of pulmonary tuberculosis in which the sputum smears are
negative for acid fast bacilli represent a diagnostic challenge in resource
constrained settings. Our objective was to validate an existing
clinical-radiographic score that assessed the probability of smear-negative
pulmonary tuberculosis (SNPT) in high incidence settings in Peru.
We included in two referral hospitals in Lima patients with clinical
suspicion of pulmonary tuberculosis and two or more negative sputum smears.
Using a published but not externally validated score, patients were
classified as having low, intermediate or high probability of pulmonary
tuberculosis. The reference standard for the diagnosis of tuberculosis was a
positive sputum culture in at least one of 2 liquid (MGIT or Middlebrook
7H9) and 1 solid (Ogawa) media. Prevalence of tuberculosis was calculated in
each of the three probability groups.
684 patients were included. 184 (27.8%) had a diagnosis of pulmonary
tuberculosis. The score did not perform well in patients with a previous
history of pulmonary tuberculosis. In patients without, the prevalence of
tuberculosis was 5.1%, 31.7% and 72% in the low,
intermediate and high probability group respectively. The area under de ROC
curve was 0.76 (95% CI 0.72–0.80) and scores ≥6 had a
positive LR of 10.9.
In smear negative suspects without previous history of tuberculosis, the
clinical-radiographic score can be used as a tool to assess the probability
of pulmonary tuberculosis and to guide the decision to initiate or defer
treatment or to requesting additional tests.
This study examined the clinical characteristics and outcome of pulmonary tuberculosis in African Americans hospitalized in a teaching hospital in south-central Los Angeles from May 1992 through April 1994. The charts of 41 African Americans with culture-positive Mycobacterium tuberculosis were reviewed. Predisposing factors for pulmonary tuberculosis were identified in nearly half of cases. Cough and fever were the most common symptoms. Seventy-six percent had positive acid-fast bacilli (AFB) smears. Nine patients were human immunodeficiency virus (HIV)-positive, and 6 of 9 HIV-positive patients had positive AFB smears whereas 17 of 19 HIV-negative patients had positive AFB smears. Radiographic changes were not significantly different between HIV-positive and HIV-negative patients. Drug resistance was identified in nine of 31 patients (29%). Eight of 41 patients (19.5%) died, with 2 being drug resistant. Human immunodeficiency virus infection was a major predisposing factor for tuberculosis, and no statistical differences were found in radiographic features or AFB smear positivity between HIV-positive and HIV-negative patients. Drug resistance and mortality were disproportionately high. These results indicate that HIV infection and drug resistance are major problems that predispose for tuberculosis infection and make its treatment difficult.
Acid fast bacilli are seldom identified by direct staining of sputum smears in patients with miliary tuberculosis, so that delays in diagnosis are common. We report 41 patients with miliary tuberculosis who had negative sputum smears and who underwent bronchoscopy, bronchial brushing, and transbronchial biopsy. In two patients the procedure was repeated. A definitive diagnosis was obtained from bronchoscopy in 34 patients (83%). Bronchial brushings yielded Mycobacterium tuberculosis in 24 of 42 bronchoscopies (57%), 13 from direct smear and a further 11 from culture only. Transbronchial biopsies were diagnostic in 30 of 41 procedures (73%), 28 from histological appearances, one from direct smear of the biopsy specimen, and another exclusively from culture. A rapid diagnosis was established in most patients (27/34), either by direct smear of brushings or biopsy specimens only (5), by histological examination only (14), or by both direct smear of brushings and biopsy specimens only (5), by histological examination only (14), or by both direct smear of brushings and histological examination (8). The diagnosis was confirmed later in a further seven patients by culture of brushings or specimens; in five of these non-caseating granulomas were initially found by histological examination. Fibreoptic bronchoscopy is a valuable technique for rapidly establishing the diagnosis of miliary tuberculosis.
Sputum for acid fast bacilli (AFB) is seldom looked for in the etiological diagnosis of tuberculous pleural effusion usually due to the absence of any parenchymal lesion radiologically, but presence of tubercle bacilli in sputum may have important epidemiological and therapeutic implication.
This study aims to evaluate the role of sputum examination for AFB in the patients of tuberculous pleural effusion with no apparent lung parenchymal lesion radiologically.
Settings and Design:
Forty-five consecutive indoor patients of suspected tuberculous pleural effusion having no apparent lung parenchymal lesion on chest radiography were selected for our study. It was a prospective and observational study conducted over a period of 1 year.
Materials and Methods:
After confirming the etiology of pleural effusion as tuberculous by biochemical, cytological, histopahtological, and microbiological tests, emphasis was given on sputum examination for AFB by smear examination and culture for Mycobacterium tuberculosis.
Sputum was bacteriologically (smear and /or culture) positive for tuberculosis in 10 out of 30 cases (33.33%) in which tuberculous etiology was confirmed by histology and /or bacteriology (definite tuberculosis). No sputum AFB (smear and culture) was found in 15 cases of probable tuberculosis where tuberculous etiology was established by indirect methods like Adenosine de aminase level more than 40 unit/l and other relevant investigations. Over all, sputum was bacteriologically smear and/or culture positive in 10 out of 45 cases (22.22%).
Careful and thorough sputum examination in cases of tuberculous pleural effusion may help as a diagnostic tool and it has therapeutic and epidemiological implications.
Mycobacterium tuberculosis; pleural biopsy; pleural effusion; sputum examination
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.
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.
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).
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.
To evaluate the efficacy of three sputum acid-fast bacillus (AFB) smears to rule out pulmonary tuberculosis, sputum AFB smear and culture results were analyzed at two university-affiliated teaching hospitals. The negative predictive value of the smear increased by only 0.2% on days 2 and 3 each, indicating that in low-prevalence populations, there is limited value in requiring three negative sputum AFB smears before discontinuing tuberculosis isolation.
The results of sputum culture for Mycobacterium tuberculosis must be awaited in most cases, which delays the start of treatment in patients with sputum smear-negative pulmonary tuberculosis. We investigated whether plasma chitotriosidase activity is a strong marker for early diagnosis of tuberculosis in patients for whom a bacillus smear is negative and tuberculosis culture is positive.
Clinical, radiological, and laboratory features were evaluated in 75 patients, 17 of whom were diagnosed as having active tuberculosis by negative acid-fast bacillus smear and positive culture, 38 as having sequel tuberculosis which was radiologically and microbiologically negative, and 20 who served as healthy controls. Serum chitotriosidase activity levels were measured in both cases and controls.
The mean age of the cases with active pulmonary tuberculosis, cases with sequel lesions, and controls was 23 ± 2.4 years, 22 ± 1.7 years, and 24 ± 2.1 years, respectively. Serum chitotriosidase levels were 68.05 ± 72.61 nmol/hour/mL in smear-negative, culture-positive pulmonary tuberculosis cases (Group A) and 29.73 ± 20.55 nmol/hour/mL in smear-negative, culture-negative sequel pulmonary tuberculosis cases (Group B). Serum chitotriosidase levels from patients in Group A were significantly higher than in Group B and Group C. There was no statistically significant difference in serum chitotriosidase levels between cases with sequel pulmonary tuberculosis (Group B, smear-negative, culture-negative) and healthy controls (Group C).
In patients with active tuberculosis and a negative sputum smear for acid-fast bacillus, plasma chitotriosidase activity seems to be a strong marker for diagnosis of active disease which can be used while awaiting culture results.
pulmonary tuberculosis; serum chitotriosidase; diagnosis; antituberculous treatment; disease activity
A repetitive sequence of Mycobacterium tuberculosis DNA was amplified by polymerase chain reaction (PCR), from sputum samples, for the diagnosis of pulmonary tuberculosis. The method of heating the sample in a boiling water bath to break down the bacterial cell wall and to release the DNA was compared with that of enzymatic lysis of bacteria and then phenol-chloroform extraction of DNA. Heating the sample was the better method with a sensitivity of approximately 10 microorganisms. A total of 78 sputum specimens prepared by heating were examined by PCR, and the results were compared with the results of acid-fast stained smears, cultures, and clinical data. M. tuberculosis was detected by PCR in all smear- and culture-positive and smear-negative, culture-positive cases. Additionally, PCR was capable of detecting four of nine cases which were smear and culture negative but clinically suspected of tuberculosis. DNA amplification by PCR is a sensitive and specific method for the diagnosis of tuberculosis, and with this simplified DNA isolation procedure it can be used in routine clinical practice.
Fibreoptic bronchoscopy with bronchial aspiration* washings and biopsy was performed in 104 patients suspected clinically and radio logically of having pulmonary tuberculosis diagnostic yield in 9230% (96/104) cases. Diagnostic yield for tuberculosis was in 69.22% (72/104)cases, it includes positive aspiration and washings smear in 38.46%(40/l04) patients,positive mycobacteriai culture alone in 26.92% (28/104) casesandpositive biopsy in 3*84% (4/ 104) patients, Non-tuberculous conditions like pneumonia and bronchogenic carcinoma were diagnosed in 19.23% (20/104) cases and 3.84% (4/104) cases respectively. These results suggest that in areas with high prevalence of tuberculosis, bronchoscopy should be performed for early diagnosis and initiation of therapy in sputum smear-negative cases of pulmonary tuberculosis.
Recent studies have suggested that two negative acid-fast bacillus (AFB) smears may be as effective as three when screening patients with suspected Mycobacterium tuberculosis for respiratory isolation purposes. However, current recommendations in Canada, the United States and Europe still support a three-smear approach.
The microbiology database of a tertiary care hospital was searched for sputum, tracheal aspirates and bronchoalveolar lavage samples from 2003 to 2007 that had been sent for mycobacterial testing. The first patient specimen to become AFB smear positive was noted. As well, the time required to collect the third specimen in hospitalized patients who remained smear negative was used to estimate the savings in isolation costs associated with a two-smear approach.
There were 8347 respiratory specimens from 5168 patients in the five-year period. Of these patients, 2.2% (116 of 5168) were AFB smear positive, of whom 55.2% (64 of 116) were culture positive for Mycobacterium tuberculosis. Overall 89% (57 of 64) of patients were identified as being AFB smear positive by the first smear, 7.8% (five of 64) were identified by the second smear and 3.2% (two of 64) were identified by further smears. Smear-negative patients spent a combined 710 days in isolation awaiting collection of the third sample at a cost of approximately $142,000 over five years.
A two-smear approach for discontinuation of respiratory isolation precautions is safe and has the potential to reduce hospital expenditures.
Humans; Infection control; Retrospective studies; Sputum/microbiology; Tuberculosis/microbiology; Tuberculosis/prevention and control
Background: Previous studies suggest that bronchoscopy and a single induced sputum sample are equally effective for diagnosing pulmonary tuberculosis.
Methods: In a prospective study of subjects with possibly active pulmonary tuberculosis, the diagnostic yield of three induced sputum tests was compared with that of bronchoscopy. Subjects either produced no sputum or (acid fast) smear negative sputum. Bronchoscopy was only performed if at least two induced sputum samples were smear negative.
Results: Of 129 subjects who completed all tests, 27 (21%) had smear negative and culture positive specimens, 14 (52%) on bronchoscopy and 26 (96%) on induced sputum (p<0.005). One patient was culture positive on bronchoscopy alone compared with 13 on induced sputum alone; 13 were culture positive on both tests. Induced sputum positivity was strikingly more prevalent when chest radiographic appearances showed any features of active tuberculosis (20/63, 32%) than when appearances suggested inactivity (1/44, 2%; p<0.005). Induced sputum costs were about one third those of bronchoscopy, and the ratio of costs of the two tests per case of tuberculosis diagnosed could be as much as 1:6.
Conclusions: In subjects investigated for possibly active or inactive tuberculosis who produce no sputum or have smear negative sputum, the most cost effective strategy is to perform three induced sputum tests without bronchoscopy. Induced sputum testing carries a high risk of nosocomial tuberculosis unless performed in respiratory isolation conditions. The cost benefits shown could be lost if risk management measures are not observed.