13 results on '"Källenius G"'
Search Results
2. Biochemical heterogeneity of Mycobacterium tuberculosis complex isolates in Guinea-Bissau
- Author
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Hoffner, S E, primary, Svenson, S B, additional, Norberg, R, additional, Dias, F, additional, Ghebremichael, S, additional, and Källenius, G, additional
- Published
- 1993
- Full Text
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3. Susceptibility of Mycobacterium malmoense to antibacterial drugs and drug combinations
- Author
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Hoffner, S E, primary, Hjelm, U, additional, and Källenius, G, additional
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- 1993
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4. Human immunodeficiency virus type 1 enhances intracellular growth of Mycobacterium avium in human macrophages
- Author
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Källenius, G, primary, Koivula, T, additional, Rydgård, K J, additional, Hoffner, S E, additional, Valentin, A, additional, Asjö, B, additional, Ljungh, C, additional, Sharma, U, additional, and Svenson, S B, additional
- Published
- 1992
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5. Mycobacterium malmoense: an easily missed pathogen
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Hoffner, S E, primary, Henriques, B, additional, Petrini, B, additional, and Källenius, G, additional
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- 1991
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6. Serovars of Mycobacterium avium complex isolated from patients in Sweden
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Hoffner, S E, primary, Källenius, G, additional, Petrini, B, additional, Brennan, P J, additional, and Tsang, A Y, additional
- Published
- 1990
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7. Periurethral anaerobic microflora of healthy girls
- Author
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Bollgren, I, primary, Källenius, G, additional, Nord, C E, additional, and Winberg, J, additional
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- 1979
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8. Failure to recruit anti-inflammatory CD103+ dendritic cells and a diminished CD4+ Foxp3+ regulatory T cell pool in mice that display excessive lung inflammation and increased susceptibility to Mycobacterium tuberculosis.
- Author
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Leepiyasakulchai C, Ignatowicz L, Pawlowski A, Källenius G, and Sköld M
- Subjects
- Animals, Antigens, CD analysis, Bacterial Load, CD4 Antigens analysis, Dendritic Cells chemistry, Disease Models, Animal, Disease Susceptibility, Female, Forkhead Transcription Factors analysis, Integrin alpha Chains analysis, Lung immunology, Lung microbiology, Lung pathology, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Inbred DBA, Pneumonia immunology, Pneumonia microbiology, Pneumonia pathology, T-Lymphocytes, Regulatory chemistry, Tuberculosis, Pulmonary microbiology, Dendritic Cells immunology, Mycobacterium tuberculosis immunology, Mycobacterium tuberculosis pathogenicity, T-Lymphocytes, Regulatory immunology, Tuberculosis, Pulmonary immunology, Tuberculosis, Pulmonary pathology
- Abstract
Susceptibility to Mycobacterium tuberculosis is characterized by excessive lung inflammation, tissue damage, and failure to control bacterial growth. To increase our understanding of mechanisms that may regulate the host immune response in the lungs, we characterized dendritic cells expressing CD103 (α(E) integrin) (αE-DCs) and CD4(+) Foxp3(+) regulatory T (T(reg)) cells during M. tuberculosis infection. In resistant C57BL/6 and BALB/c mice, the number of lung αE-DCs increased dramatically during M. tuberculosis infection. In contrast, highly susceptible DBA/2 mice failed to recruit αE-DCs even during chronic infection. Even though tumor necrosis factor alpha (TNF-α) is produced by multiple DCs and macrophage subsets and is required for control of bacterial growth, αE-DCs remained TNF-α negative. Instead, αE-DCs contained a high number of transforming growth factor beta-producing cells in infected mice. Further, we show that T(reg) cells in C57BL/6 and DBA/2 mice induce gamma interferon during pulmonary tuberculosis. In contrast to resistant mice, the T(reg) cell population was diminished in the lungs, but not in the draining pulmonary lymph nodes (PLN), of highly susceptible mice during chronic infection. T(reg) cells have been reported to inhibit M. tuberculosis-specific T cell immunity, leading to increased bacterial growth. Still, despite the reduced number of lung T(reg) cells in DBA/2 mice, the bacterial load in the lungs was increased compared to resistant animals. Our results show that αE-DCs and T(reg) cells that may regulate the host immune response are increased in M. tuberculosis-infected lungs of resistant mice but diminished in infected lungs of susceptible mice.
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- 2012
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9. African 2, a clonal complex of Mycobacterium bovis epidemiologically important in East Africa.
- Author
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Berg S, Garcia-Pelayo MC, Müller B, Hailu E, Asiimwe B, Kremer K, Dale J, Boniotti MB, Rodriguez S, Hilty M, Rigouts L, Firdessa R, Machado A, Mucavele C, Ngandolo BN, Bruchfeld J, Boschiroli L, Müller A, Sahraoui N, Pacciarini M, Cadmus S, Joloba M, van Soolingen D, Michel AL, Djønne B, Aranaz A, Zinsstag J, van Helden P, Portaels F, Kazwala R, Källenius G, Hewinson RG, Aseffa A, Gordon SV, and Smith NH
- Subjects
- Africa, Eastern epidemiology, Animals, Bacterial Typing Techniques, Cattle, Cluster Analysis, DNA Fingerprinting, DNA Transposable Elements, DNA, Bacterial chemistry, DNA, Bacterial genetics, Gene Dosage, Genotype, Molecular Sequence Data, Mycobacterium bovis genetics, Sequence Analysis, DNA, Sequence Deletion, Mycobacterium bovis classification, Mycobacterium bovis isolation & purification, Tuberculosis, Bovine epidemiology, Tuberculosis, Bovine microbiology
- Abstract
We have identified a clonal complex of Mycobacterium bovis isolated at high frequency from cattle in Uganda, Burundi, Tanzania, and Ethiopia. We have named this related group of M. bovis strains the African 2 (Af2) clonal complex of M. bovis. Af2 strains are defined by a specific chromosomal deletion (RDAf2) and can be identified by the absence of spacers 3 to 7 in their spoligotype patterns. Deletion analysis of M. bovis isolates from Algeria, Mali, Chad, Nigeria, Cameroon, South Africa, and Mozambique did not identify any strains of the Af2 clonal complex, suggesting that this clonal complex of M. bovis is localized in East Africa. The specific spoligotype pattern of the Af2 clonal complex was rarely identified among isolates from outside Africa, and the few isolates that were found and tested were intact at the RDAf2 locus. We conclude that the Af2 clonal complex is localized to cattle in East Africa. We found that strains of the Af2 clonal complex of M. bovis have, in general, four or more copies of the insertion sequence IS6110, in contrast to the majority of M. bovis strains isolated from cattle, which are thought to carry only one or a few copies.
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- 2011
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10. African 1, an epidemiologically important clonal complex of Mycobacterium bovis dominant in Mali, Nigeria, Cameroon, and Chad.
- Author
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Müller B, Hilty M, Berg S, Garcia-Pelayo MC, Dale J, Boschiroli ML, Cadmus S, Ngandolo BN, Godreuil S, Diguimbaye-Djaibé C, Kazwala R, Bonfoh B, Njanpop-Lafourcade BM, Sahraoui N, Guetarni D, Aseffa A, Mekonnen MH, Razanamparany VR, Ramarokoto H, Djønne B, Oloya J, Machado A, Mucavele C, Skjerve E, Portaels F, Rigouts L, Michel A, Müller A, Källenius G, van Helden PD, Hewinson RG, Zinsstag J, Gordon SV, and Smith NH
- Subjects
- Africa epidemiology, Animals, Bacterial Typing Techniques, Cattle, Chromosome Deletion, Molecular Sequence Data, Mycobacterium bovis classification, Mycobacterium bovis genetics, Mycobacterium bovis isolation & purification, Tuberculosis, Bovine epidemiology, Tuberculosis, Bovine microbiology
- Abstract
We have identified a clonal complex of Mycobacterium bovis present at high frequency in cattle in population samples from several sub-Saharan west-central African countries. This closely related group of bacteria is defined by a specific chromosomal deletion (RDAf1) and can be identified by the absence of spacer 30 in the standard spoligotype typing scheme. We have named this group of strains the African 1 (Af1) clonal complex and have defined the spoligotype signature of this clonal complex as being the same as the M. bovis BCG vaccine strain but with the deletion of spacer 30. Strains of the Af1 clonal complex were found at high frequency in population samples of M. bovis from cattle in Mali, Cameroon, Nigeria, and Chad, and using a combination of variable-number tandem repeat typing and spoligotyping, we show that the population of M. bovis in each of these countries is distinct, suggesting that the recent mixing of strains between countries is not common in this area of Africa. Strains with the Af1-specific deletion (RDAf1) were not identified in M. bovis isolates from Algeria, Burundi, Ethiopia, Madagascar, Mozambique, South Africa, Tanzania, and Uganda. Furthermore, the spoligotype signature of the Af1 clonal complex has not been identified in population samples of bovine tuberculosis from Europe, Iran, and South America. These observations suggest that the Af1 clonal complex is geographically localized, albeit to several African countries, and we suggest that the dominance of the clonal complex in this region is the result of an original introduction into cows naïve to bovine tuberculosis.
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- 2009
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11. Spread of drug-resistant pulmonary tuberculosis in Estonia.
- Author
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Krüüner A, Hoffner SE, Sillastu H, Danilovits M, Levina K, Svenson SB, Ghebremichael S, Koivula T, and Källenius G
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- Adult, Bacterial Typing Techniques, Estonia epidemiology, Female, Humans, Male, Microbial Sensitivity Tests, Mycobacterium tuberculosis classification, Mycobacterium tuberculosis genetics, Mycobacterium tuberculosis isolation & purification, Oligonucleotides analysis, Tuberculosis, Multidrug-Resistant epidemiology, Tuberculosis, Multidrug-Resistant microbiology, Tuberculosis, Pulmonary epidemiology, Tuberculosis, Pulmonary microbiology, Antitubercular Agents pharmacology, DNA Transposable Elements genetics, Mycobacterium tuberculosis drug effects, Polymorphism, Restriction Fragment Length, Tuberculosis, Multidrug-Resistant transmission, Tuberculosis, Pulmonary transmission
- Abstract
Restriction fragment length polymorphism (RFLP) analysis of 209 Mycobacterium tuberculosis clinical isolates obtained from newly detected pulmonary tuberculosis patients (151 male and 58 female; mean age, 41 years) in Estonia during 1994 showed that 61 isolates (29%) belonged to a genetically closely related group of isolates, family A, with a predominant IS6110 banding pattern. These strains shared the majority of their IS6110 DNA-containing restriction fragments, representing a predominant banding pattern (similarity, >65%). This family A comprised 12 clusters of identical isolates, and the largest cluster comprised 10 strains. The majority (87.5%) of all multidrug-resistant (MDR) isolates, 67.2% of all isolates with any drug resistance, but only 12% of the fully susceptible isolates of M. tuberculosis belonged to family A. These strains were confirmed by spoligotyping as members of the Beijing genotype family. The spread of Beijing genotype MDR M. tuberculosis strains was also frequently seen in 1997 to 1999. The members of this homogenous group of drug-resistant M. tuberculosis strains have contributed substantially to the continual emergence of drug-resistant tuberculosis all over Estonia.
- Published
- 2001
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12. Evolution and clonal traits of Mycobacterium tuberculosis complex in Guinea-Bissau.
- Author
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Källenius G, Koivula T, Ghebremichael S, Hoffner SE, Norberg R, Svensson E, Dias F, Marklund BI, and Svenson SB
- Subjects
- Adult, Bacterial Typing Techniques, DNA Fingerprinting, Female, Guinea-Bissau epidemiology, HIV Infections complications, HIV Infections virology, HIV-1, HIV-2, Humans, Male, Mycobacterium bovis classification, Mycobacterium bovis genetics, Mycobacterium bovis isolation & purification, Mycobacterium tuberculosis isolation & purification, Oligodeoxyribonucleotides, Polymorphism, Restriction Fragment Length, Sputum microbiology, Tuberculosis, Pulmonary complications, Tuberculosis, Pulmonary epidemiology, DNA Transposable Elements, Evolution, Molecular, Mycobacterium tuberculosis classification, Mycobacterium tuberculosis genetics, Tuberculosis, Pulmonary microbiology
- Abstract
Two hundred twenty-nine consecutive isolates of Mycobacterium tuberculosis complex from patients with pulmonary tuberculosis in Guinea-Bissau, which is located in West Africa, were analyzed for clonal origin by biochemical typing and DNA fingerprinting. By using four biochemical tests (resistance to thiophene-2-carboxylic acid hydrazide, niacin production, nitrate reductase test, and pyrazinamidase test), the isolates could be assigned to five different biovars. The characteristics of four strains conformed fully with the biochemical criteria for M. bovis, while those of 85 isolates agreed with the biochemical criteria for M. tuberculosis. The remaining 140 isolates could be allocated into one of three biovars (biovars 2 to 4) representing a spectrum between the classical bovine (biovar 1) and human (biovar 5) tubercle bacilli. By using two genotyping methods, restriction fragment length polymorphism analysis with IS6110 (IS6110 RFLP analysis) and spoligotyping, the isolates could be separated into three groups (groups A to C) of the M. tuberculosis complex. Group A (n = 95), which contained the majority of classical human M. tuberculosis isolates, had large numbers of copies of IS6110 elements (mean number of copies, 9) and a distinctive spoligotyping pattern that lacked spacers 33 to 36. Isolates of the major group, group B (n = 119), had fewer IS6110 copies (mean copy number, 5) and a spoligotyping pattern that lacked spacers 7 to 9 and 39 and mainly comprised isolates of biovars 1 to 4. Group C isolates (n = 15) had one to three IS6110 copies, had a spoligotyping pattern that lacked spacers 29 to 34, and represented biovar 3 to 5 isolates. Four isolates whose biochemical characteristics conformed with those of M. bovis clustered with the group B isolates and had spoligotype patterns that differed from those previously reported for M. bovis, in that they possessed spacers 40 to 43. Interestingly, isolates of group B and, to a certain extent, also isolates of group C showed a high degree of variability in biochemical traits, despite genotypic identity in terms of IS6110 RFLP and spoligotype patterns. We hypothesize that isolates of groups B and C have their evolutionary origin in West Africa, while group A isolates are of European descent.
- Published
- 1999
- Full Text
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13. In vitro adhesion of uropathogenic Escherichia coli to human periurethral cells.
- Author
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Källenius G, Möllby R, and Winberg J
- Subjects
- Cell Survival, Epithelial Cells, Epithelium microbiology, Escherichia coli pathogenicity, Escherichia coli ultrastructure, Female, Fimbriae, Bacterial physiology, Hemagglutination, Hot Temperature, Humans, Male, Urethra cytology, Escherichia coli physiology, Urethra microbiology
- Abstract
The in vitro adhesion of three uropathogenic strains of Escherichia coli to epithelial cells from the periurethral area (area surrounding the urethral orifice) of women with and without a history of recurrent urinary tract infections was investigated. All strains showed a specific mannose-resistant hemagglutination restricted to human erythrocytes. Since only a few hundred periurethral cells were used in each test, gentle methods were required. Optimal results were obtained with bacteria grown for 16 h at 37 degrees C in nutrient broth without shaking. The binding of bacteria seemed to be irreversible under the conditions studied, since repeated washings of the epithelial cells after incubation did not decrease the number of adhering bacteria. Chloramphenicol was used to control the number of added bacteria in the incubation system. A difference in the adhesive capacity of periurethral cells of infection-prone and healthy individuals was most evident at concentrations of 2.5 x 10(9) bacteria/ml. Electron microscope studies indicated that pili mediated the adhesion. Adhesion was correlated with the mannose-resistant hemagglutination of human erythrocytes, indicating that the pili were not type 1 pili. Day-to-day variations in the adhesiveness of the bacteria were reduced by selecting well-adhering bacteria with the aid of in vitro passage on periurethral cells or human erythrocytes, and by exclusion of bacteria with low hemagglutination ability.
- Published
- 1980
- Full Text
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