21 research outputs found

    Intact pks15/1 in Non–W-Beijing Mycobacterium tuberculosis Isolates

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    To determine whether intact pks15/1 is unique to the W-Beijing family, we investigated 147 Mycobacterium tuberculosis strains with different IS6110 genotypes. Intact pks15/1 was found in 87.8% of cerebrospinal fluid and 84.9% of sputum isolates. It was found not only in W-Beijing strains (≈97%) but also in other genotypes (38.5%–100%)

    Accuracy of line probe assays for the diagnosis of pulmonary and multidrug-resistant tuberculosis: a systematic review and meta-analysis.

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    Only 25% of multidrug-resistant tuberculosis (MDR-TB) cases are currently diagnosed. Line probe assays (LPAs) enable rapid drug-susceptibility testing for rifampicin (RIF) and isoniazid (INH) resistance and Mycobacterium tuberculosis detection. Genotype MTBDRplusV1 was WHO-endorsed in 2008 but newer LPAs have since been developed. This systematic review evaluated three LPAs: Hain Genotype MTBDRplusV1, MTBDRplusV2 and Nipro NTM+MDRTB. Study quality was assessed with QUADAS-2. Bivariate random-effects meta-analyses were performed for direct and indirect testing. Results for RIF and INH resistance were compared to phenotypic and composite (incorporating sequencing) reference standards. M. tuberculosis detection results were compared to culture. 74 unique studies were included. For RIF resistance (21 225 samples), pooled sensitivity and specificity (with 95% confidence intervals) were 96.7% (95.6–97.5%) and 98.8% (98.2–99.2%). For INH resistance (20 954 samples), pooled sensitivity and specificity were 90.2% (88.2–91.9%) and 99.2% (98.7–99.5%). Results were similar for direct and indirect testing and across LPAs. Using a composite reference standard, specificity increased marginally. For M. tuberculosis detection (3451 samples), pooled sensitivity was 94% (89.4–99.4%) for smear-positive specimens and 44% (20.2–71.7%) for smear-negative specimens. In patients with pulmonary TB, LPAs have high sensitivity and specificity for RIF resistance and high specificity and good sensitivity for INH resistance. This meta-analysis provides evidence for policy and practice

    Look, here comes the library van! Optimising the timetable of the mobile library service on the Isle of Wight

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    This article describes an approach taken to optimise the timetable of the mobile library service operating on the Isle of Wight. The mobile library visits over 90 communities on the island, offering books, DVDs, videos and CDs, and operates on a periodic timetable. The opti- misation problem is formulated as a multiple travelling salesmen model with additional time-balancing constraints on route durations. The article also shows ways in which data required for the model, in particular travel times, were gathered, and discusses practical issues arising in pre-processing the data to fit the purposes of the case study. The model is used to produce an improved timetable over the current one that implies driving time reductions of up to 25 per cent and yields routes that are better balanced in terms of time spent on the visits made each day. The model is also used to test various scenarios differing with respect to the number of locations visited and days over which the service operates.This is a post-peer-review, pre-copyedit version of an article published in OR Insight. The definitive publisher-authenticated version (Rienthong T, Walker A, Bektas T. 2011. Look, here comes the library van! Optimising the timetable of the mobile library service on the Isle of Wight. OR Insight 24(1), 49-62) is available online at: http://www.palgrave-journals.com/ori/journal/v24/n1/abs/ori201017a.htm

    Prospective evaluation of simply modified MODS assay: an effective tool for TB diagnosis and detection of MDR-TB

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    Boonchai Chaiyasirinroje1,*, Myo Nyein Aung2,3,*, Saiyud Moolphate1,4, Yuthichai Kasetjaroen5, Somsak Rienthong5, Dhanida Rienthong5, Oranuch Nampaisan1, Supalert Nedsuwan6, Wiravoot Sangchun6, Narin Suriyon7, Satoshi Mitarai4, Norio Yamada41TB/HIV Research Project, RIT, Chiang Rai, Thailand; 2Department of Public Health, Graduate School of Medicine, Juntendo University, Tokyo, Japan; 3Boromrajonani College of Nursing Nakhon Lampang (BCNLP), Lampang, Thailand; 4Research Institute of Tuberculosis (RIT), Tokyo, Japan; 5Bureau of Tuberculosis, Bangkok, Thailand; 6Chiang Rai Regional Hospital, Chiang Rai, Thailand; 7Chiang Rai Provincial Health Office, Chiang Rai, Thailand *These authors contributed equally to this workBackground and setting: Thailand is one of the highest tuberculosis (TB)-burdened countries. Chiang Rai, the northernmost province of Thailand has high tuberculosis and human immunodeficiency virus (HIV) prevalence and the laboratory workload for TB culture and drug susceptibility testing is increasing.Objectives: To evaluate the simply modified microscopic-observation drug-susceptibility assay (MODS) in the setting of a developing country.Methods: In this cross-sectional diagnostic study, a total of 202 sputum samples of clinically diagnosed TB patients were used to test the performance of MODS assay in reference to gold standard BACTEC™ MGIT™ 960 liquid culture system and Ogawa solid culture. Sputum samples were collected from clinically diagnosed TB patients. Culture growth rate and time to culture positivity were compared among three methods. Performance of modified MODS assay was evaluated for detection of mycobacterium drug resistance in reference to MGIT antimicrobial susceptibility test (AST).Result: Median time to culture positivity by MODS, solid, and liquid culture were 12, 30, and 6 days respectively. Compared to the drug susceptibility test (DST) result of reference liquid culture, the sensitivity and specificity of MODS for detection of multidrug-resistant tuberculosis (MDR-TB) was 85.7% and 97.5% respectively. MODS assay has a positive predicative value of 80% and negative predictive value of 96.5% for isoniazid resistance, 70% and 100% for rifampicin resistance, and 66.7% and 99.1% for MDR-TB.Conclusion: MODS is a highly effective screening test for detection of MDR-TB.Keywords: tuberculosis, drug resistance, MODS assay, Chiang Rai, Thailan

    Performance and acceptability of the FluoLED Easy (TM) module for tuberculosis fluorescence microscopy

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    SETTING: Tuberculosis (TB) reference laboratory in Bangkok, Thailand, and two health centres in Dar es Salaam, Tanzania. OBJECTIVES: To assess the performance and user-friendliness of a light-emitting diode (LED) module (FluoLED Easy) for TB fluorescence microscopy (FM). DESIGN: Equivalence study vs. conventional FM in Bangkok using blinded re-reading; routine detection in the health centres in Dar es Salaam compared to Ziehl-Neelsen (ZN) over 2 years, with rechecking of FM smears. RESULTS: For 461 smears re-read, 99.1% concordance with conventional FM was obtained. FluoLED introduction caused a lasting increase in detection in the routine of each of the health centres by on average 20%. Blinded rechecking failed due to unreliable registration. Onsite rechecking of a convenience sample showed absence of false-positive results in one centre and confusion with artefacts that could have been avoided by more training in the other. LED FM was highly appreciated, with both laboratories refusing to revert to ZN as originally intended. CONCLUSIONS: A simple microscope with a FluoLED module can yield results equivalent to those of conventional FM. Low cost, technical appropriateness and excellent acceptance justify its use in low-income settings, contrary to classical systems. LED FM can lead to increased sensitivity, but for optimal yield good training and quality assurance remain essential requirements
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