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Find video protocols related to scientific articles indexed in Pubmed.
Operational lessons drawn from pilot implementation of Xpert MTB/Rif in Brazil.
Bull. World Health Organ.
PUBLISHED: 05-01-2014
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The World Health Organization has endorsed the Xpert MTB/RIF (Xpert), an automated polymerase-chain-reaction-based assay, for the rapid diagnosis of tuberculosis. However, large-scale use of a new technology calls for preparation and adaptation.
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The T2 Mycobacterium tuberculosis genotype, predominant in Kampala, Uganda, shows negative correlation with antituberculosis drug resistance.
Antimicrob. Agents Chemother.
PUBLISHED: 04-28-2014
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Surveillance of the circulating Mycobacterium tuberculosis complex (MTC) strains in a given locality is important for understanding tuberculosis (TB) epidemiology. We performed molecular epidemiological studies on sputum smear-positive isolates that were collected for anti-TB drug resistance surveillance to establish the variability of MTC lineages with anti-TB drug resistance and HIV infection. Spoligotyping was performed to determine MTC phylogenetic lineages. We compared patients' MTC lineages with drug susceptibility testing (DST) patterns and HIV serostatus. Out of the 533 isolates, 497 (93.2%) had complete DST, PCR, and spoligotyping results while 484 (90.1%) participants had results for HIV testing. Overall, the frequency of any resistance was 75/497 (15.1%), highest among the LAM (34.4%; 95% confidence interval [CI], 18.5 to 53.2) and lowest among the T2 (11.5%; 95% CI, 7.6 to 16.3) family members. By multivariate analysis, LAM (adjusted odds ratio [OR(adj)], 5.0; 95% CI, 2.0 to 11.9; P < 0.001) and CAS (OR(adj), 2.9; 95% CI, 1.4.0 to 6.3; P = 0.006) families were more likely to show any resistance than was T2. All other MTC lineages combined were more likely to be resistant to any of the anti-TB drugs than were the T2 strains (OR(adj), 1.7; 95% CI, 1.0 to 2.9; P = 0.040). There were no significant associations between multidrug resistance and MTC lineages, but numbers of multidrug-resistant TB strains were small. No association was established between MTC lineages and HIV status. In conclusion, the T2 MTC lineage negatively correlates with anti-TB drug resistance, which might partly explain the reported low levels of anti-TB drug resistance in Kampala, Uganda. Patients' HIV status plays no role with respect to the MTC lineage distribution.
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A household survey on screening practices of household contacts of smear positive tuberculosis patients in Vietnam.
BMC Public Health
PUBLISHED: 01-14-2014
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Close contacts of tuberculosis (TB) patients are at increased risk of developing tuberculosis. Although passive contact screening guidelines are incorporated in the national TB control program, currently it is unknown how frequent close contacts are screened for TB in Vietnam. This study assesses current contact screening practices in Vietnam and determines the proportion of household contacts screened of newly registered TB patients.
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Clinical utility of a novel molecular assay in various combination strategies with existing methods for diagnosis of HIV-related tuberculosis in Uganda.
PLoS ONE
PUBLISHED: 01-01-2014
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Low income, high-tuberculosis burden, countries are considering selective deployment of Xpert MTB/RIF assay (Xpert) due to high cost per test. We compared the diagnostic gain of the Xpert add-on strategy with Xpert replacement strategy for pulmonary tuberculosis diagnosis among HIV-infected adults to inform its implementation.
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Impact of treating young children with antimalarials with or without antibiotics on morbidity: a cluster-randomized controlled trial in Ghana.
Int Health
PUBLISHED: 09-14-2013
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Community health workers in Dangme-West district, Ghana, treated children aged 2-59 months with fever with either artesunate-amodiaquine (AAQ) or AAQ plus amoxicillin (AAQ + AMX) within a cluster-randomized controlled trial (registration no. TDR/UNDP Trial registration A: 20189). The intervention was introduced in a stepped-wedge manner. The aim of the study was reduction of mortality. This paper reports on the reduction of morbidity, notably anaemia, severe anaemia and severe illness. Clusters of 100 children were randomized in to AAQ, AAQ + AMX and pre-intervention arms. Six months later the pre-intervention clusters were randomized in to the AAQ and AAQ + AMX arms.
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Multidrug-resistant TB in Zambia: review of national data from 2000 to 2011.
Trop. Med. Int. Health
PUBLISHED: 09-11-2013
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Multidrug-resistant tuberculosis (MDR-TB) is posing a great threat to global TB control. The burden in Zambia is not well defined because routine surveillance data are scarce. We reviewed national MDR-TB data for the last decade to inform future public health policy with respect to MDR-TB in Zambia.
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Delayed culture conversion due to cigarette smoking in active pulmonary tuberculosis patients.
Tuberculosis (Edinb)
PUBLISHED: 07-16-2013
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Although many studies have assessed factors affecting culture conversion during tuberculosis treatment, few have looked into the effect of tobacco smoking. This study included 89 active pulmonary tuberculosis patients with positive sputum culture upon presentation and collected information regarding smoking history and culture conversion after 60 days of therapy. Current smokers had a higher risk (OR 5.6; 95%CI 1.7-18.7) of non-conversion after two months of therapy when compared to never and ex-smokers. Cavities on chest X-ray and alcohol abuse were shown to confound this association. After adjustment for cavities on the chest X-ray and alcohol abuse current smoking compared to current non-smoking remained significantly associated with culture non-conversion at 60 days of treatment (adjusted OR 6.9; 95%CI 1.8-26.7, p = 0.002) with a significant (p = 0.004) trend in adjusted OR with the number of cigarettes smoked daily to 11.6 (1.8-73.4) among those smoking more than 20 cigarettes per day. In conclusion tobacco smoking was found to delay culture conversion during treatment for pulmonary tuberculosis in a dose-dependent manner. More research is needed to elucidate the effects of smoking on tuberculosis treatment response, and of smoking cessation during tuberculosis treatment.
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Epidemiology of isoniazid resistance mutations and their effect on tuberculosis treatment outcomes.
Antimicrob. Agents Chemother.
PUBLISHED: 05-20-2013
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Isoniazid resistance is highly prevalent in Vietnam. We investigated the molecular and epidemiological characteristics and the association with first-line treatment outcomes of the main isoniazid resistance mutations in Mycobacterium tuberculosis in codon 315 of the katG and in the promoter region of the inhA gene. Mycobacterium tuberculosis strains with phenotypic resistance to isoniazid from consecutively diagnosed smear-positive tuberculosis patients in rural Vietnam were subjected to Genotype MTBDRplus testing to identify katG and inhA mutations. Treatment failure and relapse were determined by sputum culture. In total, 227 of 251 isoniazid-resistant strains (90.4%) had detectable mutations: 75.3% in katG codon 315 (katG315) and 28.2% in the inhA promoter region. katG315 mutations were significantly associated with pretreatment resistance to streptomycin, rifampin, and ethambutol but not with the Beijing genotype and predicted both unfavorable treatment outcome (treatment failure or death) and relapse; inhA promoter region mutations were only associated with resistance to streptomycin and relapse. In tuberculosis patients, M. tuberculosis katG315 mutations but not inhA mutations are associated with unfavorable treatment outcome. inhA mutations do, however, increase the risk of relapse, at least with treatment regimens that contain only isoniazid and ethambutol in the continuation phase.
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For whom the bell tolls: isoniazid preventive therapy and tuberculosis drug resistance.
Sci Transl Med
PUBLISHED: 04-12-2013
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The expected increase in drug-resistant tuberculosis due to large-scale preventive treatment in people living with HIV calls for reconsidering the "double use" of isoniazid for prophylaxis and curative treatment (Mills et al., this issue).
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Alignment of new tuberculosis drug regimens and drug susceptibility testing: a framework for action.
Lancet Infect Dis
PUBLISHED: 03-24-2013
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New tuberculosis drug regimens are creating new priorities for drug susceptibility testing (DST) and surveillance. To minimise turnaround time, rapid DST will need to be prioritised, but developers of these assays will need better data about the molecular mechanisms of resistance. Efforts are underway to link mutations with drug resistance and to develop strain collections to enable assessment of new diagnostic assays. In resource-limited settings, DST might not be appropriate for all patients with tuberculosis. Surveillance data and modelling will help country stakeholders to design appropriate DST algorithms and to decide whether to change drug regimens. Finally, development of practical DST assays is needed so that, in countries where surveillance and modelling show that DST is advisable, these assays can be used to guide clinical decisions for individual patients. If combined judiciously during both development and implementation, new tuberculosis regimens and new DST assays have enormous potential to improve patient outcomes and reduce the burden of disease.
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Tuberculosis relapse in Vietnam is significantly associated with Mycobacterium tuberculosis Beijing genotype infections.
J. Infect. Dis.
PUBLISHED: 02-13-2013
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In Vietnam, the Mycobacterium tuberculosis Beijing genotype is associated with multi-drug resistance and is emerging. A possible explanation for this genotypes success is an increased rate of relapse.
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Clustering of Beijing genotype Mycobacterium tuberculosis isolates from the Mekong delta in Vietnam on the basis of variable number of tandem repeat versus restriction fragment length polymorphism typing.
BMC Infect. Dis.
PUBLISHED: 01-29-2013
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In comparison to restriction fragment length polymorphism (RFLP) typing, variable number of tandem repeat (VNTR) typing is easier to perform, faster and yields results in a simple, numerical format. Therefore, this technique has gained recognition as the new international gold standard in typing of Mycobacterium tuberculosis. However, some reports indicated that VNTR typing may be less suitable for Beijing genotype isolates. We therefore compared the performance of internationally standardized RFLP and 24 loci VNTR typing to discriminate among 100 Beijing genotype isolates from the Southern Vietnam.
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Optimal Triage Test Characteristics to Improve the Cost-Effectiveness of the Xpert MTB/RIF Assay for TB Diagnosis: A Decision Analysis.
PLoS ONE
PUBLISHED: 01-01-2013
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High costs are a limitation to scaling up the Xpert MTB/RIF assay (Xpert) for the diagnosis of tuberculosis in resource-constrained settings. A triaging strategy in which a sensitive but not necessarily highly specific rapid test is used to select patients for Xpert may result in a more affordable diagnostic algorithm. To inform the selection and development of particular diagnostics as a triage test we explored combinations of sensitivity, specificity and cost at which a hypothetical triage test will improve affordability of the Xpert assay.
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Adherence to tuberculosis treatment, sputum smear conversion and mortality: a retrospective cohort study in 48 Rwandan clinics.
PLoS ONE
PUBLISHED: 01-01-2013
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Adherence to treatment and sputum smear conversion after 2 months of treatment are thought to be important for successful outcome of tuberculosis (TB) treatment.
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Effect of changing antiretroviral treatment eligibility criteria on patient load in Kampala, Uganda.
AIDS Care
PUBLISHED: 04-28-2011
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In many resource-poor countries, CD4 count thresholds of eligibility for antiretroviral treatment (ART) were initially low (<200 cells/mm(3)) but are now being increased to improve patient survival and to reduce HIV transmission. There are few quantitative data on the effect of such increases on the demand for ART. The objective of this study was to measure HIV prevalence and the proportion of HIV-positives eligible for antiretroviral therapy at different CD4 cut-off levels among users of public health care services in Kampala, Uganda. We recruited 1200 adults from three primary care clinics in Kampala, including equal numbers of family planning (FP) clients, pregnant women, adult patients with any complaint, and persons seeking HIV counseling and testing. All participants were screened for HIV and those positive had a CD4 count done. HIV prevalence in all patients was 16.9% (203/1200). ART eligibility based on CD4 counts significantly increased from 36% at a 200 cells/mm(3) cut-off to 44% at 250 cells and to 57% at 350 cells cut-off (p for ?(2) trend<0.001). We concluded that changing cut-off levels to higher CD4 counts will significantly increase patient load in Kampalas primary care clinics, but a phased implementation should minimize negative effects on quality of care.
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Feasibility, diagnostic accuracy, and effectiveness of decentralised use of the Xpert MTB/RIF test for diagnosis of tuberculosis and multidrug resistance: a multicentre implementation study.
Lancet
PUBLISHED: 04-18-2011
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The Xpert MTB/RIF test (Cepheid, Sunnyvale, CA, USA) can detect tuberculosis and its multidrug-resistant form with very high sensitivity and specificity in controlled studies, but no performance data exist from district and subdistrict health facilities in tuberculosis-endemic countries. We aimed to assess operational feasibility, accuracy, and effectiveness of implementation in such settings.
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Rapid diagnosis of tuberculosis with the Xpert MTB/RIF assay in high burden countries: a cost-effectiveness analysis.
PLoS Med.
PUBLISHED: 04-07-2011
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Xpert MTB/RIF (Xpert) is a promising new rapid diagnostic technology for tuberculosis (TB) that has characteristics that suggest large-scale roll-out. However, because the test is expensive, there are concerns among TB program managers and policy makers regarding its affordability for low- and middle-income settings.
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Interferon-gamma release assays for tuberculosis screening of healthcare workers: a systematic review.
Thorax
PUBLISHED: 01-12-2011
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Healthcare workers (HCWs) are at increased risk of exposure to tuberculosis (TB). Traditionally, screening for latent TB infection (LTBI) is done using the tuberculin skin test (TST). Interferon-gamma release assays (IGRAs) are now increasingly being used for diagnosis of LTBI, but their role in HCW screening is unclear. A systematic review was conducted of all IGRA studies in HCWs to summarise their performance in cross-sectional and serial testing settings. By searching four electronic databases and other sources, all available studies using any one of the commercial IGRA assays in HCWs were retrieved and screened. 50 unique studies were identified which met the inclusion criteria including five from high TB incidence settings. Among 24 cross-sectional studies in low TB incidence settings, the pooled prevalence of positive IGRA using either test was significantly lower than for a positive TST. However, in high-incidence settings (n=2) there were no consistent differences in the prevalence of positive tests. IGRAs showed good correlation with occupational risk factors for TB exposure in low-incidence settings. Only 10 studies assessed use of IGRA for serial testing and all showed large variation in the rates of conversions and reversions, with no data suggesting that IGRAs are better at identifying the incidence of new TB infection than the TST. The use of IGRAs instead of TST for one-time screening may result in a lower prevalence of positive tests and fewer HCWs who require LTBI treatment, particularly in low TB incidence settings. However, the use of IGRAs for serial testing is complicated by lack of data on optimum cut-offs for serial testing and unclear interpretation and prognosis of conversions and reversions. Further longitudinal research will be required to inform guidelines on serial testing using IGRAs.
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Rates of anti-tuberculosis drug resistance in Kampala-Uganda are low and not associated with HIV infection.
PLoS ONE
PUBLISHED: 01-10-2011
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Drug resistance among tuberculosis patients in sub-Saharan Africa is increasing, possibly due to association with HIV infection. We studied drug resistance and HIV infection in a representative sample of 533 smear-positive tuberculosis patients diagnosed in Kampala, Uganda.
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The Mycobacterium tuberculosis Beijing genotype does not affect tuberculosis treatment failure in Vietnam.
Clin. Infect. Dis.
PUBLISHED: 09-15-2010
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Studies have suggested that the Mycobacterium tuberculosis Beijing genotype causes more severe clinical disease and higher treatment failure rates with standard regimens, possibly in association with an increased risk of acquiring drug resistance. We studied the effect of genotype on treatment failure in a rural area in Vietnam where multidrug resistance is strongly associated with the Beijing genotype.
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Tuberculosis acquired outside of households, rural Vietnam.
Emerging Infect. Dis.
PUBLISHED: 08-26-2010
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Using population-based data from rural Vietnam, we assessed tuberculosis (TB) transmission within and outside of households. Eighty-three percent of persons with recent household TB were infected by different strains of Mycobacterium tuberculosis than were their household members. This result argues against the effectiveness of active TB case finding among household members.
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Long delays and missed opportunities in diagnosing smear-positive pulmonary tuberculosis in Kampala, Uganda: a cross-sectional study.
PLoS ONE
PUBLISHED: 07-09-2010
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Early detection and treatment of tuberculosis cases are the hallmark of successful tuberculosis control. We conducted a cross-sectional study at public primary health facilities in Kampala city, Uganda to quantify diagnostic delay among pulmonary tuberculosis (PTB) patients, assess associated factors, and describe trajectories of patients health care seeking.
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Validation of the GenoType MTBDRplus assay for diagnosis of multidrug resistant tuberculosis in South Vietnam.
BMC Infect. Dis.
PUBLISHED: 06-03-2010
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To control multidrug resistant tuberculosis (MDR-TB), the drug susceptibility profile is needed to guide therapy. Classical drug susceptibility testing (DST) may take up to 2 to 4 months. The GenoType MTBDRplus test is a commercially available line-probe assay that rapidly detects Mycobacterium tuberculosis (MTB) complex, as well as the most common mutations associated with rifampin and isoniazid resistance.We assessed sensitivity and specificity of the assay by using a geographically representative set of MTB isolates from the South of Vietnam.
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Low HIV testing rates among tuberculosis patients in Kampala, Uganda.
BMC Public Health
PUBLISHED: 03-31-2010
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HIV testing among tuberculosis patients is critical in improving morbidity and mortality as those found to be HIV positive will be offered a continuum of care including ART if indicated. We conducted a cross-sectional study in three Kampala City primary care clinics: to assess the level of HIV test uptake among newly diagnosed pulmonary tuberculosis (PTB) patients; to assess patient and health worker factors associated with HIV test uptake; and to determine factors associated with HIV test uptake at the primary care clinics
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National survey of tuberculosis prevalence in Viet Nam.
Bull. World Health Organ.
PUBLISHED: 02-22-2010
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To estimate the prevalence of tuberculosis in Viet Nam with data from a population-based survey, compare it with the prevalence estimated by the World Health Organization, and identify major demographic determinants of tuberculosis prevalence.
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Patient-centred tuberculosis treatment delivery under programmatic conditions in Tanzania: a cohort study.
BMC Med
PUBLISHED: 11-19-2009
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Directly observed therapy (DOT) remains the cornerstone of the global tuberculosis (TB) control strategy. Tanzania, one of the 22 high-burden countries regarding TB, changed the first-line treatment regimen to contain rifampicin-containing fixed-dose combination for the full 6 months of treatment. As daily health facility-based DOT for this long period is not feasible for the patient, nor for the health system, Tanzania introduced patient centred treatment (PCT). PCT allows patients to choose for daily DOT at a health facility or at their home by a supporter of choice. The introduction of fixed dose combinations in the intensive and continuation phase made PCT feasible by eliminating the risk of selective drug taking by patients and reducing the number of tablets to be taken. The approach was tested in three districts with the objective to assess the effect of this strategy on TB treatment outcomes
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Mycobacterium tuberculosis genotype and case notification rates, rural Vietnam, 2003-2006.
Emerging Infect. Dis.
PUBLISHED: 10-29-2009
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Tuberculosis case notification rates (CNRs) for young adults in Vietnam are increasing. To determine whether this finding could reflect emergence of Mycobacterium tuberculosis Beijing genotype, we studied all new sputum smear-positive pulmonary tuberculosis patients registered for treatment in 3 rural districts in Vietnam during 2003-2006. Beijing strain infections were more frequent in younger patients (15-24 years of age, 53%) than in older patients (31%; p<0.001). The increase in CNRs for youngest patients was larger for disease caused by the Beijing genotype than by other genotypes, but the difference was not significant. For patients 15-24 years of age, 85% of fluctuations in CNRs between years was caused by fluctuations in Beijing genotype infections compared with 53% and 23% in the groups 25-64 and >or=65 years of age, respectively (p<0.001). These findings suggest that young adults may be responsible for introducing Beijing strains into rural Vietnam.
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The Beijing genotype is associated with young age and multidrug-resistant tuberculosis in rural Vietnam.
Int. J. Tuberc. Lung Dis.
PUBLISHED: 06-27-2009
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Associations between multidrug resistance and the Mycobacterium tuberculosis Beijing genotype have been described mainly in populations with poor tuberculosis (TB) control such as prisons and inner cities, and may reflect shared risk factors rather than a biological association.
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Targeted BCG vaccination against severe tuberculosis in low-prevalence settings: epidemiologic and economic assessment.
Epidemiology
PUBLISHED: 03-20-2009
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BCG vaccine protects against the severe forms of tuberculosis (TB) in children. Several low-prevalence countries are reviewing their policy, usually shifting from universal vaccination to vaccination of infants in high-risk groups only. We combined an epidemiologic analysis with a cost-effectiveness analysis to evaluate the cost-effectiveness of targeted strategies.
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Research on implementation of interventions in tuberculosis control in low- and middle-income countries: a systematic review.
PLoS Med.
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Several interventions for tuberculosis (TB) control have been recommended by the World Health Organization (WHO) over the past decade. These include isoniazid preventive therapy (IPT) for HIV-infected individuals and household contacts of infectious TB patients, diagnostic algorithms for rule-in or rule-out of smear-negative pulmonary TB, and programmatic treatment for multidrug-resistant TB. There is no systematically collected data on the type of evidence that is publicly available to guide the scale-up of these interventions in low- and middle-income countries. We investigated the availability of published evidence on their effectiveness, delivery, and cost-effectiveness that policy makers need for scaling-up these interventions at country level.
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Trends in childhood tuberculosis in Zambia: a situation analysis.
J. Trop. Pediatr.
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To ascertain childhood tuberculosis (TB) trends, human immunodeficiency virus (HIV) co-infection rates and multi-drug resistant TB (MDR-TB) prevalence rates in Zambia.
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Combined species identification, genotyping, and drug resistance detection of Mycobacterium tuberculosis cultures by MLPA on a bead-based array.
PLoS ONE
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The population structure of Mycobacterium tuberculosis is typically clonal therefore genotypic lineages can be unequivocally identified by characteristic markers such as mutations or genomic deletions. In addition, drug resistance is mainly mediated by mutations. These issues make multiplexed detection of selected mutations potentially a very powerful tool to characterise Mycobacterium tuberculosis. We used Multiplex Ligation-dependent Probe Amplification (MLPA) to screen for dispersed mutations, which can be successfully applied to Mycobacterium tuberculosis as was previously shown. Here we selected 47 discriminative and informative markers and designed MLPA probes accordingly to allow analysis with a liquid bead array and robust reader (Luminex MAGPIX technology). To validate the bead-based MLPA, we screened a panel of 88 selected strains, previously characterised by other methods with the developed multiplex assay using automated positive and negative calling. In total 3059 characteristics were screened and 3034 (99.2%) were consistent with previous molecular characterizations, of which 2056 (67.2%) were directly supported by other molecular methods, and 978 (32.0%) were consistent with but not directly supported by previous molecular characterizations. Results directly conflicting or inconsistent with previous methods, were obtained for 25 (0.8%) of the characteristics tested. Here we report the validation of the bead-based MLPA and demonstrate its potential to simultaneously identify a range of drug resistance markers, discriminate the species within the Mycobacterium tuberculosis complex, determine the genetic lineage and detect and identify the clinically most relevant non-tuberculous mycobacterial species. The detection of multiple genetic markers in clinically derived Mycobacterium tuberculosis strains with a multiplex assay could reduce the number of TB-dedicated screening methods needed for full characterization. Additionally, as a proportion of the markers screened are specific to certain Mycobacterium tuberculosis lineages each profile can be checked for internal consistency. Strain characterization can allow selection of appropriate treatment and thereby improve treatment outcome and patient management.
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Increased transmission of Mycobacterium tuberculosis Beijing genotype strains associated with resistance to streptomycin: a population-based study.
PLoS ONE
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Studies have shown that the Mycobacterium tuberculosis Beijing genotype is an emerging pathogen that is frequently associated with drug resistance. This suggests that drug resistant Beijing strains have a relatively high transmission fitness compared to other drug-resistant strains.
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Frequency and predictors for late start of antiretroviral therapy in primary care clinics, Kampala, Uganda.
J. Acquir. Immune Defic. Syndr.
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Access to antiretroviral treatment (ART) has improved greatly in many parts of the world, including Uganda, yet, many patients delay to start ART even when registered within the HIV services. We assessed, in a routine ambulatory care setting, what proportion of patients start ART late and the associated factors.
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Urban movement and alcohol intake strongly predict defaulting from tuberculosis treatment: an operational study.
PLoS ONE
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High levels of defaulting from treatment challenge tuberculosis control in many African cities. We assessed defaulting from tuberculosis treatment in an African urban setting.
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Which new diagnostics for tuberculosis, and when?
J. Infect. Dis.
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Recently, new diagnostic tools for tuberculosis detection and resistance testing have become available. The World Health Organization endorses new tuberculosis diagnostics by using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process. This endorsement process takes place when limited evidence beyond test accuracy is available. There is a need to provide guidance to tuberculosis programs about which new diagnostics to scale up and how best to position them in diagnostic algorithms. To speed adoption of new diagnostics for tuberculosis, the policy recommendation process should be revised to consist of 2 steps: technical recommendation and programmatic recommendation. Technical recommendation would follow the GRADE process and be based on accuracy with limited cost and feasibility data, while programmatic recommendation would include patient-important outcomes, cost-effectiveness when implemented under routine conditions, and factors critical to successful scale-up. The evidence for both steps should be systematically collected, but each requires different study designs.
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Mixed tuberculosis infections in rural South Vietnam.
J. Clin. Microbiol.
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Tuberculosis patients may be infected with or have disease caused by more than one Mycobacterium tuberculosis strain, usually referred to as "mixed infections." These have mainly been observed in settings with a very high tuberculosis incidence and/or high HIV prevalence. We assessed the rate of mixed infections in a population-based study in rural Vietnam, where the prevalences of both HIV and tuberculosis are substantially lower than those in previous studies looking at mixed infections. In total, 1,248 M. tuberculosis isolates from the same number of patients were subjected to IS6110 restriction fragment length polymorphism (RFLP) typing, spoligotyping, and variable-number-tandem-repeat (VNTR) typing. We compared mixed infections identified by the presence of (i) discrepant RFLP and spoligotype patterns in isolates from the same patient and (ii) double alleles at ? 2 loci by VNTR typing and assessed epidemiological characteristics of these infections. RFLP/spoligotyping and VNTR typing identified 39 (3.1%) and 60 (4.8%) mixed infections, respectively (Cohens kappa statistic, 0.57). The number of loci with double alleles in the VNTR pattern was strongly associated with the proportion of isolates with mixed infections according to RFLP/spoligotyping (P < 0.001). Mixed infections occurred more frequently in newly treated than in previously treated patients, were significantly associated with minor X-ray abnormalities, and were almost significantly associated with lower sputum smear grades. Although the infection pressure in our study area is lower than that in previously studied populations, mixed M. tuberculosis infections do occur in rural South Vietnam in at least 3.1% of cases.
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Multidrug resistance among new tuberculosis cases: detecting local variation through lot quality-assurance sampling.
Epidemiology
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Current methodology for multidrug-resistant tuberculosis (MDR TB) surveys endorsed by the World Health Organization provides estimates of MDR TB prevalence among new cases at the national level. On the aggregate, local variation in the burden of MDR TB may be masked. This paper investigates the utility of applying lot quality-assurance sampling to identify geographic heterogeneity in the proportion of new cases with multidrug resistance.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.