| 1. |
- Antusheva, E., et al.
(author)
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Outbreak of tuberculosis in a closed setting: views on transmission based on results from molecular and conventional methods
- 2016
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In: Journal of Hospital Infection. - : Elsevier BV. - 0195-6701. ; 93:2, s. 187-190
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Journal article (peer-reviewed)abstract
- Background: This study describes an outbreak of tuberculosis (TB) in a nursing home for men with mental disorders where residency is lengthy or permanent. This type of setting can provide a model of transmission as contact with the rest of society is extremely limited. Aim: To determine if cases of TB, diagnosed around the same time and in the same place, are linked based on results using molecular and conventional methods. Methods: The strains of Mycobacterium tuberculosis were analysed by drug resistance testing and mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTRV). Microbiological results were related to clinical history and time of diagnosis. Findings: Nine patients were diagnosed with TB, and strains were recovered from seven of these patients. Unexpectedly, the strains with the same genotype showed different patterns of resistance, and only two strains demonstrated identical patterns. MIRU-VNTR analysis demonstrated that one patient was infected with two different strains. Conclusion: Variation between the strains indicates that the outbreak may have arisen from several sources of infection. The variation in resistance indicates that rapid emergence of antimicrobial resistance is possible. As such, several questions are raised concerning source of infection, development of disease, resistance and mixed infections. (C) 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
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| 2. |
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| 3. |
- Brudey, Karine, et al.
(author)
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Molecular epidemiology of Mycobacterium tuberculosis in western Sweden.
- 2004
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In: Journal of clinical microbiology. - 0095-1137. ; 42:7, s. 3046-51
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Journal article (peer-reviewed)abstract
- The genetic diversity of Mycobacterium tuberculosis isolates among patients from Sweden was determined by a combination of two PCR-based techniques (spoligotyping and variable number of tandem repeats analysis). It resulted in a clustering of 23.6% of the isolates and a rate of recent transmission of 14.1%. The clustered isolates mainly belonged to the Haarlem family (23.2%), followed by the Beijing (9.8%), Latin American and Mediterranean (LAM; 8%), and East African-Indian (EAI; 6.2%) families. A comparison of the spoligotypes with those in the international spoligotyping database showed that 62.5% of the clustered isolates and 36.6% of all isolates typed were grouped into six major shared types. A comparison of the spoligotypes with those in databases for Scandinavian countries showed that 33% of the isolates belonged to an ill-defined T family, followed by the EAI (22%), Haarlem (20%), LAM (11%), Central Asian (5%), X (5%), and Beijing (4%) families. Both the highest number of cases and the proportion of clustered cases were observed in patients ages 15 to 39 years. Nearly 10% of the isolates were resistant to one or more drugs (essentially limited to isoniazid monoresistance). However, none of the strains were multidrug resistant. Data on the geographic origins of the patients showed that more than two-thirds of the clustered patients with tuberculosis were foreign-born individuals or refugees. These results are explained on the basis of both the historical links within specific countries and recently imported cases of tuberculosis into Sweden.
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| 4. |
- Burguière, Adeline, et al.
(author)
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LosA, a key glycosyltransferase involved in the biosynthesis of a novel family of glycosylated acyltrehalose lipooligosaccharides from Mycobacterium marinum.
- 2005
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In: The Journal of biological chemistry. - 0021-9258. ; 280:51, s. 42124-33
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Journal article (peer-reviewed)abstract
- Members of the genus Mycobacterium are characterized by cell envelopes rich in unusual free lipids, interacting with a covalently anchored mycolyl-arabinogalactan matrix. Previous studies have shown that Mycobacterium marinum produces large amounts of a diacylglycosylphenolphthiocerol, "phenolic" glycolipid. When cultivated on liquid Sauton medium, traces of a polar lipooligosaccharide (LOS) glycolipid antigen were also previously indicated. In this study, it was found that growth of the type strain of M. marinum on solid Sauton or Middlebrook 7H10 agar gave substantial, but different, amounts of a family of four major trehalose-based LOSs. The core pentasaccharide LOS-I was a rhamnosyl diglucosyl-acylated trehalose. The heptasaccharide, LOS-II, was derived from LOS-I by adding xylose accompanied by a novel sugar (X); repeated addition of this sugar unit X gave the octasaccharide LOS-III. LOS-IV has a decasaccharide component with two additional unusual sugar units, YZ. In a recent study (Alexander, D. C., Jones, J. R., Tan, T., Chen, J. M., and Liu, J. (2004) J. Biol. Chem. 279, 18824-18833), chromatographically similar glycolipids were assigned to the family of phosphatidylinositol mannosides (PIMs) and a "PimF" (Rv1500) glycosyltransferase implicated in the conversion of a supposed "PIM5" to a "PIM7." The present study indicates that these putative PIMs are in fact members of the phosphorus-free LOS family of glycolipids and that the protein product of Rv1500, which we have now termed LosA, is a glycosyltransferase involved in transferring sugars to LOS-III to form LOS-IV of M. marinum.
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| 5. |
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| 6. |
- Fjällbrant, Harald, 1961, et al.
(author)
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BCG scar and tuberculin reactivity in children and adults.
- 2008
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In: Scandinavian journal of infectious diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 40:5, s. 387-92
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Journal article (peer-reviewed)abstract
- Bacille Calmette-Guérin (BCG) vaccination generally leads to scar formation and tuberculin skin test (TST) reactivity. This study aimed at analysing these 2 parameters and their correlation in a setting with a low prevalence of tuberculosis. Retrospectively, we analysed 314 children and 390 adults living in Sweden and known from records or individual recall to have undergone BCG vaccination. A BCG scar was present in 161 (51%) of the children and in 340 (87%) of the adults. Among children with a scar, 94 (58%) were TST-positive (>/=6 mm) compared to 23 (15%) of 154 children lacking a visible scar. Among adults with a scar, 258 (76%) were TST- positive compared to 23 (46%) of 50 with no scar. Out of 152 non-vaccinated adults, 142 (94.4%) were TST-negative. When 175 TST-negative health care students were BCG-vaccinated in a prospective part of the study, 174 (99%) were found to develop a scar. In essence, the study showed a positive correlation between scar presence and TST reactivity. Furthermore, BCG vaccination of adults in the present setting resulted in consistent scar formation, while scar prevalence in previously vaccinated children was low.
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| 7. |
- Fjällbrant, Harald, 1961, et al.
(author)
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Primary vaccination and revaccination of young adults with BCG: a study using immunological markers.
- 2007
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In: Scandinavian journal of infectious diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 39:9, s. 792-8
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Journal article (peer-reviewed)abstract
- Questions have been raised about the effectiveness of Bacille Calmette-Guérin (BCG) vaccination against tuberculosis (TB) in adults. We therefore analysed the immune response after BCG vaccination in primary-vaccinated and revaccinated young adults. 31 tuberculin skin test (TST) negative healthy students were BCG-vaccinated; 15 were primary-vaccinated and 16 revaccinated. Tuberculin-induced lymphocyte transformation (LT) and cytokine production of peripheral blood mononuclear cells were studied before BCG vaccination, as well as after 2 months and 1 y. In the primary-vaccinated as well as the revaccinated group the LT response increased after 2 months and remained significantly higher than baseline values after 1 y. In both groups the interferon-gamma (IFN-gamma) levels increased significantly after 2 months and the increase was maintained after 1 y. LT increased more in the revaccinated group than in the primary-vaccinated group, while the increase in IFN-gamma response did not differ between the 2 groups. Both primary vaccination and revaccination of TST negative young adults caused a significant increase in the T-helper 1-type immune response, suggesting a protective effect against TB. The present in vitro results thus support the policy in several low-endemic countries of primary vaccination as well as revaccination of young adults at risk of TB exposure.
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| 8. |
- Fjällbrant, Harald, 1961, et al.
(author)
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Tuberculin skin test reactivity of health care students in a country with a low prevalence of tuberculosis.
- 2010
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In: The international journal of tuberculosis and lung disease. - 1815-7920. ; 14:10, s. 1272-1279
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Journal article (peer-reviewed)abstract
- SETTING: Health care students in Sweden. OBJECTIVE: To analyse the distribution of tuberculin skin test (TST) reactions and epidemiological factors related to TST reactivity. DESIGN: TST reactivity was analysed in 1190 students. A linear regression model was created for the relative contribution of background factors of TST reactivity. A subgroup of 287 non-vaccinated subjects was comparatively skin-tested with Mycobacterium avium sensitin and tuberculin. RESULTS: Among non-bacille Calmette-Guérin (BCG) vaccinated students, 91% had no TST reaction (0 mm induration) and reactions of ≥10 mm were found in 2.9%, whereas 34% of BCG-vaccinated students had no TST reaction and 42% had reactions of ≥10 mm. The expected contribution to TST reactivity was 6.0 mm for a history of BCG vaccination, 3.0 mm for a country of birth with medium/high incidence of TB and 1.6 mm per 10 years of age. The sensitin reactions exceeded the TST reactions by ≥3 mm in 52% of the comparatively tested subjects with TST reactions of ≥1 mm. CONCLUSION: BCG vaccination, cross-reactivity with non-tuberculous mycobacteria, geographic origin and age had a decisive influence on TST reactivity. Most non-vaccinated health care students were non-reactive, which highlights the need to organise preventive measures in settings where TB exposure is expected.
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| 9. |
- Fäldt, Jenny, 1971, et al.
(author)
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Activation of human neutrophils by mycobacterial phenolic glycolipids.
- 1999
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In: Clinical and experimental immunology. - 0009-9104. ; 118:2, s. 253-60
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Journal article (peer-reviewed)abstract
- The interaction between mycobacterial phenolic glycolipids (PGLs) and phagocytes was studied. Human neutrophils were allowed to interact with each of four purified mycobacterial PGLs and the neutrophil production of reactive oxygen metabolites was followed kinetically by luminol-/isoluminol-amplified chemiluminescence. The PGLs from Mycobacterium tuberculosis and Mycobacterium kansasii, respectively, were shown to stimulate the production of oxygen metabolites, while PGLs from Mycobacterium marinum and Mycobacterium bovis BCG, respectively, were unable to induce an oxidative response. Periodate treatment of the M. tuberculosis PGL decreased the production of oxygen radicals, showing the importance of the PGL carbohydrate moiety for the interaction. The activation, however, could not be inhibited by rhamnose or fucose, indicating a complex interaction which probably involves more than one saccharide unit. This is in line with the fact that the activating PGLs from M. tuberculosis and M. kansasii contain tri- and tetrasaccharides, respectively, while the nonactivating PGLs from M. marinum and M. bovis BCG each contain a monosaccharide. The complement receptor 3 (CR3) has earlier been shown to be of importance for the phagocyte binding of mycobacteria, but did not appear to be involved in the activation of neutrophils by PGLs. The subcellular localization of the reactive oxygen metabolites formed was related to the way in which the glycolipids were presented to the cells.
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| 10. |
- Fäldt, Jenny, 1971, et al.
(author)
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Priming of human neutrophils by mycobacterial lipoarabinomannans: role of granule mobilisation.
- 2001
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In: Microbes and infection. - 1286-4579. ; 3:13, s. 1101-9
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Journal article (peer-reviewed)abstract
- Lipoarabinomannans (LAMs) from mycobacteria were investigated concerning their effect on human neutrophils. Two types of LAM, the mannose-capped ManLAM from the virulent Mycobacterium tuberculosis H37Rv and the mannose-lacking AraLAM from a rapidly growing mycobacterial strain were used. Neither AraLAM nor ManLAM induced any significant direct activation of the NADPH-oxidase. Both LAMs, however, primed the neutrophils so that subsequent stimulation with the peptide chemoattractants fMet-Leu-Phe (fMLF), Trp-Lys-Tyr-Met-Val-DMet (WKYMVm) and the mammalian lactose-binding lectin galectin-3 resulted in a markedly enhanced oxidative response. The LAM-induced priming was accompanied by an increased exposure of complement receptors 1 and 3 as well as the formyl peptide receptor on the neutrophil surface, suggesting that the enhanced oxidative response could be due to upregulation of receptors on the cell surface as a result of granule mobilisation. Since LAM-primed neutrophils released 65% of the cell content of gelatinase but showed no increased release of vitamin B(12)-binding protein, mobilisation of the gelatinase granules rather than the specific granules is concluded to be responsible for the priming effects. This is in agreement with the subcellular localisation of receptors for fMLF, WKYMVm, as well as galectin-3, which are stored in the secretory vesicles and gelatinase granules. The priming effect appeared very similar to that of Escherichia coli lipopolysaccharide, and since no differences in activity could be detected between AraLAM and ManLAM, we hypothesize that the lipid anchor of the LAM is responsible for the priming effects.
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