Dataset Information

Prospective cross-sectional evaluation of the small membrane filtration method for diagnosis of pulmonary tuberculosis.

ABSTRACT: Smear microscopy has suboptimal sensitivity, and there is a need to improve its performance since it is commonly used to diagnose tuberculosis (TB). We prospectively evaluated the diagnostic accuracy of the small membrane filtration (SMF) method, an approach that uses a vacuum manifold and is designed to concentrate bacilli onto a filter that can be examined microscopically. We enrolled hospitalized adults suspected to have pulmonary TB in Kampala, Uganda. We obtained a clinical history and three spontaneously expectorated sputum specimens for smear microscopy (direct, concentrated, and SMF), MGIT (mycobacterial growth indicator tube) 960 and Lowenstein-Jensen (LJ) cultures, and Xpert MTB/RIF testing. We performed per-specimen (primary) and per-patient analyses. From October 2012 to June 2013, we enrolled 212 patients (579 sputum specimens). The participants were mostly female (63.2%), and 81.6% were HIV infected; their median CD4 cell count was 47 cells/?l. Overall, 19.0%, 20.4%, 27.1%, 25.2%, and 25.9% of specimens tested positive by direct smear, concentrated smear, MGIT culture, LJ culture, and Xpert test, respectively. In the per-specimen analysis, the sensitivity of the SMF method (48.5%; 95% confidence interval [CI], 37.4 to 59.6) was lower than those of direct smear (60.9%; 51.4 to 70.5 [P = 0.0001]) and concentrated smear (63.3%; 53.6 to 73.1 [P < 0.0001]). Subgroup analyses showed that SMF performed poorly in specimens having a low volume or low bacterial load. The SMF method performed poorly compared to standard smear techniques and was sensitive to sample preparation techniques. The optimal laboratory SMF protocol may require striking a fine balance between sample dilution and filtration failure rate.

SUBMITTER: Jones-Lopez E

PROVIDER: S-EPMC4097702 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Prospective cross-sectional evaluation of the small membrane filtration method for diagnosis of pulmonary tuberculosis.

Jones-López Edward E Manabe Yukari C YC Palaci Moises M Kayiza Carol C Armstrong Derek D Nakiyingi Lydia L Ssengooba Willy W Gaeddert Mary M Kubiak Rachel R Almeida Júnior Pedro P Alland David D Dietze Reynaldo R Joloba Moses M Ellner Jerrold J JJ Dorman Susan E SE

Journal of clinical microbiology 20140507 7

Smear microscopy has suboptimal sensitivity, and there is a need to improve its performance since it is commonly used to diagnose tuberculosis (TB). We prospectively evaluated the diagnostic accuracy of the small membrane filtration (SMF) method, an approach that uses a vacuum manifold and is designed to concentrate bacilli onto a filter that can be examined microscopically. We enrolled hospitalized adults suspected to have pulmonary TB in Kampala, Uganda. We obtained a clinical history and thre ...[more]

PMID: 24808236

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Project description:BackgroundThe diagnosis of tuberculosis (TB) in resource-limited settings relies on Ziehl-Neelsen (ZN) smear microscopy. LED fluorescence microscopy (LED-FM) has many potential advantages over ZN smear microscopy, but requires evaluation in the field. The aim of this study was to assess the sensitivity/specificity of LED-FM for the diagnosis of pulmonary TB and whether its performance varies with the timing of specimen collection.Methods and findingsAdults with cough ?2 wk were enrolled consecutively in Ethiopia, Nepal, Nigeria, and Yemen. Sputum specimens were examined by ZN smear microscopy and LED-FM and compared with culture as the reference standard. Specimens were collected using a spot-morning-spot (SMS) or spot-spot-morning (SSM) scheme to explore whether the collection of the first two smears at the health care facility (i.e., "on the spot") the first day of consultation followed by a morning sample the next day (SSM) would identify similar numbers of smear-positive patients as smears collected via the SMS scheme (i.e., one on-the-spot-smear the first day, followed by a morning specimen collected at home and a second on-the-spot sample the second day). In total, 529 (21.6%) culture-positive and 1,826 (74.6%) culture-negative patients were enrolled, of which 1,156 (49%) submitted SSM specimens and 1,199 (51%) submitted SMS specimens. Single LED-FM smears had higher sensitivity but lower specificity than single ZN smears. Using two LED-FM or two ZN smears per patient was 72.8% (385/529, 95% CI 68.8%-76.5%) and 65.8% (348/529, 95% CI 61.6%-69.8%) sensitive (p<0.001) and 90.9% (1,660/1,826, 95% CI 89.5%-92.2%) and 98% (1,790/1,826, 95% CI 97.3%-98.6%) specific (p<0.001). Using three LED-FM or three ZN smears per patient was 77% (408/529, 95% CI 73.3%-80.6%) and 70.5% (373/529, 95% CI 66.4%-74.4%, p<0.001) sensitive and 88.1% (95% CI 86.5%-89.6%) and 96.5% (95% CI 96.8%-98.2%, p<0.001) specific. The sensitivity/specificity of ZN smear microscopy and LED-FM did not vary between SMS and SSM.ConclusionsLED-FM had higher sensitivity but, in this study, lower specificity than ZN smear microscopy for diagnosis of pulmonary TB. Performance was independent of the scheme used for collecting specimens. The introduction of LED-FM needs to be accompanied by appropriate training, quality management, and monitoring of performance in the field.Trial registrationCurrent Controlled Trials ISRCTN53339491. Please see later in the article for the Editors' Summary.

Project description:BackgroundDelayed diagnosis and treatment of tuberculosis (TB) results in severe disease and a higher mortality. It also leads to an increased period of infectivity in the community. The objective of this study was to determine the length of delays, and analyze the factors affecting the delay from onset of symptoms of pulmonary tuberculosis (PTB) until the commencement of treatment.MethodsIn randomly selected TB management units (TBMUs), i.e. government health institutions which have diagnosing and treatment facilities for TB in Amhara Region, we conducted a cross sectional study from September 1-December 31/2003. Delay was analyzed from two perspectives, 1. Period between onset of TB symptoms to first visit to any health provider (health seeking period), and from the first health provider visit to initiation of treatment (health providers' delay), and 2. Period between onset of TB symptoms to first visit to a medical provider (patients' delay), and from this visit to commencement of anti-TB treatment (health systems' delay). Patients were interviewed on the same date of diagnosis using a semi-structured questionnaire. Logistics regression analysis was applied to analyze the risk factors of delays.ResultsA total of 384 new smear positive PTB patients participated in the study. The median total delay was 80 days. The median health-seeking period and health providers' delays were 15 and 61 days, respectively. Conversely, the median patients' and health systems' delays were 30 and 21 days, respectively. Taking medical providers as a reference point, we found that forty eight percent of the subjects delayed for more than one month. Patients' delays were strongly associated with first visit to non-formal health providers and self treatment (P < 0.0001). Prior attendance to a health post/clinic was associated with increased health systems' delay (p < 0.0001).ConclusionDelay in the diagnosis and treatment of PTB is unacceptably high in Amhara region. Health providers' and health systems' delays represent the major portion of the total delay. Accessing a simple and rapid diagnostic test for TB at the lowest level of health care facility and encouraging a dialogue among all health providers are imperative interventions.

Project description:BackgroundTuberculosis (TB) is among the top 10 causes of mortality and the first killer among infectious diseases worldwide. One of the factors fuelling the TB epidemic is the global rise of multidrug resistant TB (MDR-TB). The aim of this study was to determine the magnitude and factors associated with MDR-TB in the Tigray Region, Ethiopia.MethodThis study employed a facility-based cross-sectional study design, which was conducted between July 2018 and August 2019. The inclusion criteria for the study participants were GeneXpert-positive who were not under treatment for TB, PTB patients' ≥15 years of age and who provided written informed consent. A total of 300 participants were enrolled in the study, with a structured questionnaire used to collect data on clinical, sociodemographic and behavioral factors. Sputum samples were collected and processed for acid-fast bacilli staining, culture and drug susceptibility testing. Drug susceptibility testing was performed using a line probe assay. Logistic regression was used to analyze associations between outcome and predictor variables.ResultsThe overall proportion of MDR-TB was 16.7% (11.6% and 32.7% for new and previously treated patients, respectively). Of the total MDR-TB isolates, 5.3% were pre-XDR-TB. The proportion of MDR-TB/HIV co-infection was 21.1%. A previous history of TB treatment AOR 3.75; 95% CI (0.7-2.24), cigarette smoking AOR 6.09; CI (1.65-2.50) and patients who had an intermittent fever (AOR = 2.54, 95% CI = 1.21-5.4) were strongly associated with MDR-TB development.ConclusionsThe magnitude of MDR-TB observed among new and previously treated patients is very alarming, which calls for an urgent need for intervention. The high proportion of MDR-TB among newly diagnosed cases indicates ongoing transmission, which suggests the need for enhanced TB control program performance to interrupt transmission. The increased proportion of MDR-TB among previously treated cases indicates a need for better patient management to prevent the evolution of drug resistance. Assessing the TB control program performance gaps and an optimal implementation of the WHO recommended priority actions for the management of drug-resistant TB, is imperative to help reduce the current high MDR-TB burden in the study region.

Dataset Information

Prospective cross-sectional evaluation of the small membrane filtration method for diagnosis of pulmonary tuberculosis.

Publications

Prospective cross-sectional evaluation of the small membrane filtration method for diagnosis of pulmonary tuberculosis.

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