Added value of bleach sedimentation microscopy for diagnosis of pulmonary tuberculosis: cost-effectiveness study

IUATLD Conference, Paris, 200

Evaluation of the performance and feasability of the fluorescein diacetate (FTA) vital staining method for follow up of Tuberculosis (TB) treatment

IUATLD Conference, Paris, 200

Performance of LED-Based Fluorescence Microscopy to Diagnose Tuberculosis in a Peripheral Health Centre in Nairobi.

Sputum microscopy is the only tuberculosis (TB) diagnostic available at peripheral levels of care in resource limited countries. Its sensitivity is low, particularly in high HIV prevalence settings. Fluorescence microscopy (FM) can improve performance of microscopy and with the new light emitting diode (LED) technologies could be appropriate for peripheral settings. The study aimed to compare the performance of LED-FM versus Ziehl-Neelsen (ZN) microscopy and to assess feasibility of LED-FM at a low level of care in a high HIV prevalence country

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

ABSTRACT: 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. METHODS: We did a prospective diagnostic study in a Medecins Sans Frontieres-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. RESULTS: 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 ([greater than or equal to]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. CONCLUSIONS: 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

Anti-tuberculosis drug resistance survey in West Nile, Uganda

IUATLD Conference, Paris, 200

Bleach sedimentation: an opportunity to optimize smear microscopy for tuberculosis diagnosis in settings of high prevalence of HIV

BACKGROUND: The purpose of the study was to evaluate the performance and feasibility of tuberculosis diagnosis by sputum microscopy after bleach sedimentation, compared with by conventional direct smear microscopy, in a setting of high prevalence of HIV. METHODS: In a community-based study in Kenya (a population in which 50% of individuals with tuberculosis are infected with HIV), individuals with suspected pulmonary tuberculosis submitted 3 sputum specimens during 2 consecutive days, which were examined by blind evaluation. Ziehl-Neelsen-stained smears were made of fresh specimens and of specimens that were processed with 3.5% household bleach followed by overnight sedimentation. Two different cutoffs for acid-fast bacilli (AFB) per 100 high-power fields (HPF) were used to define a positive smear: >10 AFB/100 HPF and 1 AFB/100 HPF. Four smear-positive case definitions, based on 1 or 2 positive smears with the 1 AFB or 10 AFB cutoff, were used. RESULTS: Of 1879 specimens from 644 patients, 363 (19.3%) and 460 (24.5%) were positive by bleach sedimentation microscopy, compared with 301 (16.0%) and 374 (19.9%) by direct smear microscopy, with use of the 10 AFB/100 HPF (P < .001) and 1 AFB/100 HPF (P < .001) cutoffs, respectively. Regardless of the case definition used, bleach sedimentation microscopy detected significantly more positive cases than did direct smear microscopy: 26.7% (172 of 644) versus 21.7% (140 of 644), respectively, with the case definition of 1 positive smear and the 1 AFB/100 HPF cutoff (P < .001), and 21.4% (138 of 644) versus 18.6% (120 of 644), respectively, with the case definition of 1 positive smear and the 10 AFB/100 HPF cutoff (P < .001). Inter- and intrareader reproducibility were favorable, with kappa coefficients of 0.83 and 0.91, respectively. Bleach sedimentation was relatively inexpensive and was not time consuming. CONCLUSIONS: Bleach sedimentation microscopy is an effective, simple method to improve the yield of smear microscopy in a setting of high prevalence of HIV. Further evaluation of this method, under operational conditions, is urgently needed to determine its potential as a tool for tuberculosis control

Prevalence and risk factors of brucellosis among febrile patients attending a community hospital in south western Uganda

Human brucellosis, a chronic disease contracted through contact with animals and consuption of unpasteurized dairy products is underreported in limited-resource countries. This cross-sectional study aimed to determine the prevalence and risk factors of brucellosis among febrile patients attending a community hospital in South western Uganda. A questionnaire that captured socio-demographic, occupational and clinical data was administered. Blood samples were tested for Brucella antibodies using Rose Bengal Plate Test (RBPT) and blood culture with standard aerobic BACTEC bottle was done. Of 235 patients enrolled, prevalence of brucellosis (RBPT or culture confirmed) was 14.9% (95%CI 10.6-20.1) with a culture confrmation in 4.3% of the participants. The factors independently associated with brucellosis were consumption of raw milk (aOR 406.15, 95% CI 47.67-3461.69); history of brucellosis in the family (aOR 9.19, 95% CI 1.98-42.54); and selling hides and skins (aOR 162.56, 95% CI 2.86-9256.31). Hepatomegaly (p < 0.001), splenomegaly (p = 0.018) and low body mass index (p = 0.032) were more common in patients with brucellosis compared to others. Our findings reveal a high prevalence of brucellosis among febrile patients and highlight a need for implementing appropiate tests, public awareness activities and vaccination of animals to control and eliminate the disease

Nevirapine versus Efavirenz for patients co-infected with HIV and Tuberculosis: A Randomised Non-Inferiority Trial

BACKGROUND: In countries with a high incidence of HIV and tuberculosis co-infection, nevirapine and efavirenz are widely used as antiretroviral therapy but both interact with antituberculosis drugs. We aimed to compare efficacy and safety of a nevirapine-based antiretroviral therapy (started at full dose) with an efavirenz-based regimen in co-infected patients. METHODS: We did a multicentre, open-label, randomised, non-inferiority trial at three health centres in Maputo, Mozambique. We enrolled adults (≥18 years) with tuberculosis and previously untreated HIV infection (CD4 cell counts <250 cells per μL) and alanine aminotransferase and total bilirubin concentrations of less than five times the upper limit of normal. 4-6 weeks after the start of tuberculosis treatment, we randomly allocated patients (1:1) with central randomisation, block sizes of two to six, and stratified by site and CD4 cell count to nevirapine (200 mg twice daily) or efavirenz (600 mg once daily), plus lamivudine and stavudine. The primary endpoint was virological suppression at 48 weeks (HIV-1 RNA <50 copies per mL) in all patients who received at least one dose of study drug (intention-to-treat population); death and loss to follow-up were recorded as treatment failure. The non-inferiority margin for the difference of efficacy was 10%. We assessed efficacy in intention-to-treat and per-protocol populations and safety in all patients who received study drug. This study is registered with ClinicalTrials.gov, number NCT00495326. FINDINGS: Between October, 2007, and March, 2010, we enrolled 285 patients into each group. 242 (85%) patients in the nevirapine group and 233 (82%) patients in the efavirenz group completed follow-up. In the intention-to-treat population, 184 patients (64·6%, 95% CI 58·7-70·1) allocated nevirapine achieved virological suppression at week 48, as did 199 patients (69·8%, 64·1-75·1) allocated efavirenz (one-sided 95% CI of the difference of efficacy 11·7%). In the per-protocol population, 170 (70·0%, 63·8-75·7) of 243 patients allocated nevirapine achieved virological suppression at week 48, as did 194 (78·9%, 73·2-83·8) of 246 patients allocated efavirenz (one-sided 95% CI 15·4%). The median CD4 cell count at randomisation was 89 cells per μL. 15 patients substituted nevirapine with efavirenz and six patients substituted efavirenz with nevirapine. 20 patients allocated nevirapine (7%) had grade 3-4 increase of alanine aminotransferase compared with 17 patients allocated efavirenz (6%). Three patients had severe rash after receipt of nevirapine (1%) but no patients did after receipt of efavirenz. 18 patients in the nevirapine group died, as did 17 patients in the efavirenz group. INTERPRETATION: Although non-inferiority of the nevirapine-regimen was not shown, nevirapine at full dose could be a safe, acceptable alternative for patients unable to tolerate efavirenz. FUNDING: French Research Agency for HIV/AIDS and hepatitis (ANRS)

Evaluation of Combined LED-Fluorescence Microscopy and Bleach Sedimentation for Diagnosis of Tuberculosis at Peripheral Health Service Level

Sputum microscopy is the only diagnostic for tuberculosis (TB) available at peripheral levels of health service in resource-poor countries. Its sensitivity is reduced in high HIV-prevalence settings. Sodium hypochlorite (NaOCl) specimen sedimentation prior microscopy and light-emitting diode (LED)-fluorescence microscopy (FM) can individually improve performance of microscopy. This study aimed to evaluate the performance of combined LED-FM and NaOCl sputum sedimentation for TB detection at peripheral level of health services