Direct microscopy versus sputum cytology analysis and bleach sedimentation for diagnosis of tuberculosis: a prospective diagnostic study

Background  

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.     

Feasibility of magnetic bead technology for concentration of mycobacteria in sputum prior to fluorescence microscopy

Background  

Direct sputum smear microscopy is the mainstay of TB diagnosis in most low and middle income countries, and is highly specific for Mycobacterium tuberculosis in such settings. However it is limited by low sensitivity, particularly in HIV co-infected patients. Concentration by centrifugation has been reported to be more sensitive than direct smear preparation, but is only suitable for referral laboratories. Simpler concentration methods that could be applied in peripheral laboratories are urgently needed.     

Post-bronchoscopy sputum: improving the diagnostic yield in smear negative pulmonary TB

Introduction

Patients with suspected active Pulmonary Tuberculosis (PTB) who are Acid-Fast Bacilli (AFB) smear negative or non-productive of sputum may undergo bronchoalveolar lavage. However, post-bronchoscopy sputum (PBS) sampling is not routine. The aim of this study was to establish the potential diagnostic value of PBS sampling.

Methods

A retrospective study of patients attending a London University hospital with microbiologically confirmed PTB between January 2004 and December 2010. Patients who were AFB smear negative or non-productive of sputum were eligible if sputum sampling was performed within 7 days of bronchoscopy.

Results

Over the study period, 236 patients had microbiologically confirmed smear negative PTB of which 57 patients were eligible for the study. 15 patients (26.3%) were infected with HIV. 19 patients (33.3%) converted to AFB sputum smear positivity post-bronchoscopy and 5 patients (8.8%) were exclusively AFB sputum smear positive on PBS microscopy. Mycobacterium tuberculosis was cultured from the PBS of 43 patients (75.4%) and of these, 4 (7.0%) were exclusively PBS culture positive.

Conclusion

PBS analysis can provide a simple method of rapidly diagnosing pulmonary tuberculosis. In this cohort, M. tuberculosis culture yield was increased by 7% through PBS sampling. This study has important infection control implications with nearly one third of patients becoming more infectious after bronchoscopy.     

GeneXpert MTB/RIF for rapid diagnosis and rifampin resistance detection of endobronchial tuberculosis

Background and objective

Delayed diagnosis and treatment of tuberculosis (TB) contribute to poor outcomes, especially for endobronchial TB (EBTB), which typically leads to tracheobronchial stenosis. Finding rapid and accurate diagnostic tools for EBTB is crucial. GeneXpert Mycobacterium tuberculosis (MTB)/rifampin (RIF) was recommended by the World Health Organization (WHO) as a standard molecular biological diagnostic technique for MTB. The aim of this study was to evaluate the efficacy of GeneXpert MTB/RIF for diagnosing EBTB and for evaluating RIF resistance.

Methods

Biopsy tissue and bronchial brushings from EBTB patients were prospectively assessed with GeneXpert MTB/RIF. The diagnostic yields of auramine O‐stained sputum smears and bronchial brush smears were obtained, and the results were compared with the cultures of sputum and biopsy tissues for MTB.

Results

In 61 confirmed cases of EBTB, the sensitivities of sputum smear, bronchial brush smear, sputum culture and tissue culture to diagnose EBTB were 13.1%, 32.8%, 36.1% and 68.9%, respectively. For bronchial brushings and biopsies, our data showed sensitivities of 57.4% and 63.9%, respectively, and a specificity of 100% for GeneXpert MTB/RIF, and these results were superior to those of sputum smears, bronchial brush smears and sputum culture. GeneXpert MTB/RIF for bronchial brushings and biopsies showed complementarity in its diagnostic performance. Resistance to RIF was identified in 17.4% (8/46) of GeneXpert MTB‐positive cases.

Conclusion

GeneXpert MTB/RIF may enable more rapid EBTB diagnosis and determination of RIF resistance, which are crucial for timely treatment.

     

The role of the third acid-fast bacillus smear in tuberculosis screening for infection control purposes: A controversial topic revisited

INTRODUCTION:

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.

METHODS:

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.

RESULTS:

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.

CONCLUSION:

A two-smear approach for discontinuation of respiratory isolation precautions is safe and has the potential to reduce hospital expenditures.     

Sensitivity of direct versus concentrated sputum smear microscopy in HIV-infected patients suspected of having pulmonary tuberculosis

Background  

Sputum concentration increases the sensitivity of smear microscopy for the diagnosis of tuberculosis (TB), but few studies have investigated this method in human immunodeficiency virus (HIV)-infected individuals.     

The role and performance of chest X-ray for the diagnosis of tuberculosis: A cost-effectiveness analysis in Nairobi,Kenya

Background  

The objective of this study was to establish 1) the performance of chest X-ray (CXR) in all suspects of tuberculosis (TB), as well as smear-negative TB suspects and 2) to compare the cost-effectiveness of the routine diagnostic pathway using Ziehl-Neelsen (ZN) sputum microscopy followed by CXR if case of negative sputum result (ZN followed by CXR) with an alternative pathway using CXR as a screening tool (CXR followed by ZN).     

Daily adjunctive therapy with vitamin D3 and phenylbutyrate supports clinical recovery from pulmonary tuberculosis: a randomized controlled trial in Ethiopia

Objective

Immunotherapy using vitamin D (vitD₃) and phenylbutyrate (PBA ) may support standard drug regimens used to treat infectious diseases. We investigated if vitD₃ + PBA enhanced clinical recovery from pulmonary tuberculosis (TB ).

Methods

A randomized controlled trial was conducted in Addis Ababa, Ethiopia. Patients with smear‐positive or smear‐negative TB received daily oral supplementation with 5000 IU vitD₃ and 2 × 500 mg PBA or placebo for 16 weeks, together with 6‐month chemotherapy. Primary end‐point: reduction of a clinical composite TB score at week 8 compared with baseline using modified intention‐to‐treat (mITT , n = 348) and per‐protocol (n = 296) analyses. Secondary end‐points: primary and modified TB scores (week 0, 4, 8, 16, 24), sputum conversion, radiological findings and plasma 25(OH )D₃ concentrations.

Results

Most subjects had low baseline plasma 25(OH )D₃ levels that increased gradually in the vitD₃ + PBA group compared with placebo (P < 0.0001) from week 0 to 16 (mean 34.7 vs. 127.4 nmol L^?1). In the adjusted mITT analysis, the primary TB score was significantly reduced in the intervention group at week 8 (?0.52, 95% CI ?0.93, ?0.10; P = 0.015) while the modified TB score was reduced at week 8 (?0.58, 95% CI ?1.02, ?0.14; P = 0.01) and 16 (?0.34, 95% CI ?0.64, ?0.03; P = 0.03). VitD₃ + PBA had no effect on longitudinal sputum‐smear conversion (P = 0.98). Clinical adverse events were more common in the placebo group (24.3%) compared with the vitD₃ + PBA group (12.6%).

Conclusion

Daily supplementation with vitD₃ + PBA may ameliorate clinical TB symptoms and disease‐specific complications, while the intervention had no effect on bacterial clearance in sputum.

     

Induced sputum for the diagnosis of pulmonary tuberculosis: Is it useful in clinical practice?

BACKGROUND:

Diagnosing pulmonary tuberculosis (PTB) is challenging in patients who are unable to spontaneously expectorate. Published evidence suggests that induced sputum (IS) is the least invasive and most cost-effective method of diagnosis, and should be used before fibre-optic bronchoscopy (FOB).

METHODS:

The medical records of 337 adults treated for PTB in northern Alberta between 1997 and 2007 were reviewed to determine whether local practice patterns reflect the evidence. Microbiological data were collected from the Provincial Laboratory for Public Health. Demographic information was collected from the patients’ charts.

RESULTS:

A total of 8.5% (26 of 307) of PTB patients had IS collected, whereas 35.8% (110 of 307) underwent FOB. Among FOB patients, 56.4% (62 of 110) had no sputum sent before the procedure and 29% (18 of 62) of these patients were smear positive. Only five patients referred for FOB had IS sent previously. There were no demographic factors predictive of IS use, whereas being an inpatient at a teaching facility or having a nodule or mass on chest x-ray was predictive of FOB referral. Because so few IS samples were available, not all patients had spontaneously expectorated sputum, IS and FOB tests performed; thus, the calculated yields were not comparable with one another.

CONCLUSIONS:

Despite published evidence recommending IS collection before FOB referral in suspected PTB patients, clinicians in our health region appeared to prefer early FOB over IS by a large margin. This practice pattern is less cost effective and exposes patients and health care workers to greater risk. Further research is needed to identify the reasons for the underuse of sputum induction.     

Prevalence of pulmonary tuberculosis among adults in selected slums of Delhi city

Background

A survey was carried out to estimate the point prevalence of bacteriologically positive pulmonary tuberculosis (PTB) among persons ≥15 years of age residing in Jhuggi–Jhopri (JJ) colonies – urban slums in Delhi, India implementing Directly Observed Treatment strategy since 1998.

Barriers to Follow-Up of an Abnormal Pap Smear in Latina Women Referred for Colposcopy

BACKGROUND  

Lower rates of follow-up after an abnormal Pap smear in racial and ethnic minorities may contribute to the higher incidence and mortality rates of cervical cancer seen in these groups.     

Role of serum adenosine deaminase in pulmonary tuberculosis

Background

Definitive laboratory diagnosis and confirmation of tuberculosis remains a major challenge because of lack of specificity and sensitivity of diagnostic methods especially in sputum smear negative tuberculosis. Many studies have proved the role of ADA in diagnosis of tuberculosis in effusion fluids and a decrease in ADA activity after treatment. This study was aimed to investigate the role of serum ADA level as an early diagnostic and prognostic marker for pulmonary tuberculosis (PTB).

Perfusing chemotherapy by percutaneous lung puncture “holing” for pulmonary tuberculoma—a ten-year single center experience

Background

Pulmonary tuberculoma is a special form of secondary pulmonary tuberculosis, with a poor response to drug treatment. We used the method of drug administration via percutaneous lung puncture “holing” to treat pulmonary tuberculoma and observe its short- and long-term efficacy, summing up our 10-year clinical experience.

Methods

A total of 54 patients with pulmonary tuberculoma were included in this study. They themselves were taken as the control group. Three to six months of conventional anti-tuberculosis treatment was conducted firstly. Then those patients with no changes of sizes in tuberculoma were recommended to receive drug administration via percutaneous lung puncture. Isoniazid (INH, 0.1 g) and amikacin (AMK, 0.2 g) were injected into tuberculoma (once or twice per week, 10 times as a course of treatment).

Results

After two months of drug treatment by lung puncture, the sputum smear test showed the negative conversion rate of tubercle bacillus was 87% (13/15), and the positive conversion rate was 8% (3/39). The tuberculosis bacillus culture indicated that the negative conversion rate was 100% (7/7). The reexamination after one year showed the negative conversion rate of tubercle bacillus in the sputum smear test was 80% (4/5). About 58% (31/54) of tuberculoma disappeared or significantly reduced, in which, 40% (21/54) of tuberculoma disappeared. The tuberculoma diameter reduced from 3.6 cm × 2.8 cm to 1.7 cm × 1.1 cm on average. Side-effects included postoperative pneumothorax 9% (5/54), hemoptysis 7% (4/54) and fever 11% (6/54). A total of 34 patients were followed up for five years, and the disappearance rate of tuberculoma was up to 47% (16/34), with no recurrence.

Conclusions

The drug administration via percutaneous lung puncture—“holing” in pulmonary tuberculoma takes a significant effect obviously, good short- and long-term effects and less side effects.KEY WORDS : Percutaneous lung puncture, pulmonary tuberculoma, holing     

A minimum 5.0 ml of sputum improves the sensitivity of acid-fast smear for Mycobacterium tuberculosis

Detection of acid-fast bacilli (AFB) by sputum smear supports treatment decisions with pulmonary tuberculosis (TB), but smear sensitivity for Mycobacterium tuberculosis is only approximately 45 to 75%. In an effort to increase sensitivity, smears were prepared using a minimum sputum volume of 5.0 ml. Sensitivity of smears during a 39-mo period (n = 1,849) using >/= 5.0 ml of sputum was 92. 0%, significantly greater (p < 0.001) than a sensitivity of 72.5% in a previous 24-mo period (n = 3,486) when all specimens were processed regardless of volume. All new cases of TB (n = 18) were smear-positive with >/= 5.0 ml of sputum before treatment, and all were receiving antituberculosis drugs at hospital discharge. In contrast, significantly fewer new cases of TB (14 of 26, p = 0.002) were positive before treatment when smears were prepared using sputum of any volume, and significantly fewer of these new TB cases (18 of 26, p = 0.03) were receiving treatment at hospital discharge. The eight cases without treatment were smear-negative. These results indicate that acid-fast smear using >/= 5.0 ml of sputum increases sensitivity for M. tuberculosis and accelerates treatment of TB.     

Rapid screening of MDR-TB using molecular Line Probe Assay is feasible in Uganda

Background  

About 500 new smear-positive Multidrug-resistant tuberculosis (MDR-TB) cases are estimated to occur per year in Uganda. In 2008 in Kampala, MDR-TB prevalence was reported as 1.0% and 12.3% in new and previously treated TB cases respectively. Line probe assays (LPAs) have been recently approved for use in low income settings and can be used to screen smear-positive sputum specimens for resistance to rifampicin and isoniazid in 1-2 days.     

Comparative study of effect of Withania somnifera as an adjuvant to DOTS in patients of newly diagnosed sputum smear positive pulmonary tuberculosis

Background

Ashwagandha (Withania somnifera Linn.) a rejuvenative herb has long been used as an immunomodulator in Indian subcontinent. As immunity plays an important role in pathogenesis and treatment of tuberculosis (TB), so role of W. somnifera as an adjuvant has been studied on selected parameter.

Cost-effectiveness of various diagnostic approaches for occupational asthma

BACKGROUND:

Diagnosis of occupational asthma (OA) by specific inhalation challenge (SIC) can be costly and is not always available. The use of sputum testing to avoid this in some patients may be a more cost-effective alternative.

OBJECTIVES:

To compare the cost-effectiveness of SIC with serial measurements of sputum cell counts (sputum testing) and peak expiratory flow (PEF) monitoring.

METHODS:

Clinical data and testing costs for OA in 49 patients were collected during a previously published trial, modelled and compared using TreeAge Pro. Clinical outcome was the percentage of accurately diagnosed patients, using SIC as the gold standard. The PEF approach used the most accurate assessment of five experts who were blinded to SIC results. Differences in the proportion of eosinophils during periods on and off work were used for the sputum testing approach and in PEF/sputum for the combined approach. Unit costs were estimated from charges in Canadian hospitals. Data were analyzed by one-way and two-way analyses, and by probabilistic sensitivity analysis using a Monte Carlo simulation technique.

RESULTS:

The PEF approach had an estimated accuracy of 52% and cost $365 per patient tested. Compared with PEF monitoring, sputum testing was more accurate and cost an estimated $255 for each additional OA patient correctly diagnosed. SIC costs per additional correct diagnosis were $11,032 compared with sputum testing and $6,458 compared with PEF monitoring. The combined PEF/sputum testing approach was not cost-effective in the base case analysis, but cannot be excluded according to probabilistic sensitivity analyses.

CONCLUSIONS:

Although SIC remains the reference test to diagnose OA, when this test is not available, sputum testing is a cost-effective alternative to PEF for diagnosis of OA.     

Sputum neutrophilia can mask eosinophilic bronchitis during exacerbations

BACKGROUND:

Exacerbations of airway disease are eosinophilic, neutrophilic, both or neither. The primary objective of the present study was to identify whether the treatment of a neutrophilic bronchitis can unmask an associated eosinophilia.

METHODS:

A retrospective survey of 2160 consecutive sputum cell counts from 1343 patients with airway disease was conducted to identify patients with an isolated neutrophilic bronchitis, which was defined as a sputum total cell count of greater than or equal to 12×10⁶ cells/g of sputum and a proportion of neutrophils of 80% or greater. The characteristics of the patients who subsequently demonstrated sputum eosinophilia (3% or greater) within eight weeks of resolving the neutrophilia were compared with the patients who subsequently did not have sputum eosinophilia.

RESULTS:

Two hundred thirty-seven patients had 273 neutrophilic exacerbations. The sputum was re-examined within eight weeks in 65 patients (27.4%), of whom 38 (58.5%) had resolution of the neutrophilic bronchitis after treatment with an antibiotic. Of these 38 patients, 13 (34%) showed eosinophilia.

CONCLUSIONS:

A neutrophilic exacerbation of airway disease was observed to mask sputum eosinophilia in one-third of patients who had sputum cell counts available before and after antibiotic therapy. Hence, the absence of sputum eosinophilia during an infective exacerbation should not be used as an indication to reduce the dose of corticosteroids. To optimize therapy, repeat sputum cell count measurements are recommended after antibiotic treatment before changing corticosteroid treatment.     

The efficiency of sputum cell counts in cystic fibrosis

BACKGROUND:

Technical factors relating to processing viscid sputum in cystic fibrosis (CF) and their influence on the reproducibility and validity of cell counts need to be evaluated. In addition, the methods need to be standardized so that they can be applied clinically and in research.

OBJECTIVE:

To examine the efficiency, reliability and validity of processing small volumes of spontaneously expectorated sputum from subjects with CF.

METHODS:

Sputum was collected from adults with CF (n=35) and compared with sputum from adults with infective bronchitis or bronchiectasis (IB/B) (n=16), or with asthma or chronic obstructive pulmonary disease (AS/COPD) (n=25). Selected sputum (100 mg to 200 mg) was processed with dithiothreitol (0.1%) and filtered. Total cell count (TCC) and viability were obtained in a counting chamber and cytospins were prepared and stained with Wright’s for a differential cell count. Sputum and filter remnant were processed for TCC, viability and differential cell count, and the efficiency was determined by comparing the mean loss in cell yield to the filter. Two different portions from the same sputum sample were processed for cell counts to determine reproducibility. Results were compared with those from IB/B and AS/COPD groups.

RESULTS:

Efficiency of cell dispersal was excellent and similar to that in AS/COPD and IB/B groups. Reproducibility of cell counts from two portions of a sputum sample was high (R≥0.80). CF sputum demonstrated a raised TCC and neutrophilia similar to IB/B but significantly higher than AS/COPD.

CONCLUSION:

The selection method of evaluating cell counts in viscid CF sputum is efficient, reproducible and valid.     

Heterogeneity of bronchitis in airway diseases in tertiary care clinical practice

BACKGROUND:

Sputum cell counts have identified inflammatory subtypes of bronchitis in relatively small numbers of subjects with asthma, chronic obstructive pulmonary disease (COPD) and chronic cough in research studies. The prevalence of different subtypes of bronchitis in routine clinical practice, however, has not been reported.

OBJECTIVE:

To examine the heterogeneity of bronchitis and its relationship to the severity of airflow obstruction.

METHODS:

A retrospective cross-sectional survey based on a computerized database of spontaneous or induced sputum cell counts examined in a large university tertiary respiratory outpatient clinic.

RESULTS:

The database contained 4232 consecutive sputum records from 2443 patients with chronic cough (39%), asthma (37%), asthma with COPD (9%), COPD (13%) and bronchiectasis (3%). Total and differential cell counts were obtained from 86% of successful sputum samples. Induced sputum provided more viable samples than spontaneous expectorate. Approximately one-third of patients with asthma and one-fifth of patients with COPD experience eosinophilic bronchitis. Asthmatic patients with moderate to severe airflow obstruction had a greater number of sputum eosinophils. There was a significantly higher number of total cell counts and percentage of neutrophils in the sputum of COPD patients with moderate and severe airflow obstruction than in those with mild airflow obstruction.

CONCLUSION:

There is heterogeneity in the cellularity of sputum in various airway diseases. Patients with clinically stable airway diseases may have high sputum cell counts. During exacerbations, more patients may experience neutrophilic bronchitis. Severity of airflow obstruction is associated with eosinophilic bronchitis in patients with asthma, and neutrophilic bronchitis in patients with nonasthmatic COPD.