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| 2. |
- Fjällbrant, Harald, 1961, et al.
(författare)
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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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Ingår i: The international journal of tuberculosis and lung disease. - 1815-7920. ; 14:10, s. 1272-1279
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Jönsson, Bodil, 1959, et al.
(författare)
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Non-tuberculous mycobacteria and their surface lipids efficiently induced IL-17 production in human T cells
- 2012
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Ingår i: Microbes and Infection. - : Elsevier BV. - 1286-4579. ; 14:13, s. 1186-1195
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-17 (IL-17) is produced by a subset of CD4(+) T helper (Th) lymphocytes known as Th17 cells. In humans, IL-1 beta, enhanced by IL-6 and IL-23 is crucial for differentiation of these cells. IL-17 evokes inflammation and is involved in host defence against microorganisms, although little is known about its role in diseases caused by non-tuberculous mycobacteria. The genus Mycobacterium contains both obligate and opportunistic pathogens as well as saprophytes, and the mycobacterial cell envelope is unique in its abundance of lipids. Here we investigated IL-17 and IL-23 production in human PBMC in response to intact UV-inactivated mycobacteria and mycobacterial surface lipids from two opportunistic (Mycobacterium avium and Mycobacterium abscessus) and one generally non-pathogenic (Mycobacterium gordonae) species. Representative Gram-positive (Enterococcus faecalis, Streptococcus mitis) and Gram-negative (Escherichia coli) bacteria were included as controls. Intact mycobacteria induced production of large amounts of IL-17, while IL-17 responses to control bacteria were negligible. Purified CD4(+) T cells, but not CD4-depleted cell fractions, produced this IL-17. Isolated mycobacterial surface lipids induced IL-17, but not IL-23 production. The ability of the non-tuberculous mycobacteria to induce IL-17 production in CD4(+) T cells was the same regardless of the pathogenic potential of the particular mycobacterial species.
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| 5. |
- Jönsson, Bodil, 1959, et al.
(författare)
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Phagocytosis and cytokine response to rough and smooth colony variants of Mycobacterium abscessus by human peripheral blood mononuclear cells.
- 2013
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 121:1, s. 45-55
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Tidskriftsartikel (refereegranskat)abstract
- Mycobacterium abscessus is a non-tuberculous mycobacteria able to cause opportunistic infections in selected patient groups. During the last decades it has emerged as a cause of chronic pulmonary infection in patients with cystic fibrosis (CF). M. abscessus strains exhibit either smooth or rough colony morphology. Strains exhibiting the rough phenotype more often cause pulmonary infections in CF patients than did the smooth ones. Here, we examined phagocytosis and production of cytokines by human peripheral blood mononuclear cells, in response to M. abscessus strains with smooth and rough colony phenotype. The rough isolates all formed multicellular cords, similar to what is observed in Mycobacterium tuberculosis. Monocytes were generally unable to internalize these rough cord isolates, in contrast with the smooth ones. Furthermore, the rough M. abscessus strains induced a distinct cytokine profile differing from that induced by the smooth ones. Rough isolates induced significantly less IL-10 and tumour necrosis factor compared to smooth strains, but more IL-1β. Both varieties induced equal amounts of IFN-γ, IL-17, IL-23, IL-6, IL-8 and equally little IL-12. The ability to withstand phagocytosis might be a virulence factor contributing to the capacity of rough M. abscessus strains to give persistent pulmonary infections.
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| 6. |
- Jönsson, Bodil, 1959, et al.
(författare)
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The surface lipids of non-tuberculous mycobacteria suppress production of phagocyte activating cytokines in human peripheral blood mononuclear cells
- 2012
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Ingår i: Microbes and Infection. - : Elsevier BV. - 1286-4579. ; 14:9, s. 768-777
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Tidskriftsartikel (refereegranskat)abstract
- The genus Mycobacterium includes obligate pathogens as well as opportunistic and non-pathogenic species ubiquitous in the environment. Mycobacteria have a unique cell wall abundant in lipids. Here we investigated cytokine production by human peripheral blood mononuclear cells (PBMC) in response to the opportunistic mycobacteria Mycobacterium avium and Mycobacterium abscessus, the non-pathogenic Mycobacterium gordonae and extracted surface lipids from the three species. The cytokine response elicited by mycobacteria, regardless of their pathogenic potential, differed distinctly from that induced by control Gram-positive (Enterococcus faecalis, Streptococcus mitis) and Gram-negative (Escherichia coli) bacteria. Mycobacteria induced no IL-12 and less TNF and IFN-γ compared with conventional Gram-positive bacteria. IL-10 was induced by all the mycobacteria and this production was partly responsible for the down-regulation of IL-12 and IFN-γ. The capacity of the Gram-positive bacterium E. faecalis to induce IL-12, as well as TNF and IFN-γ, in human PBMCs was strongly reduced when mycobacterial lipids were added. The mycobacterial surface lipids down-regulated the production of IL-12 and IFN-γ without eliciting IL-10 production. Our results show that mycobacteria evade triggering production of phagocyte activating cytokines (IL-12, TNF and IFN-γ) and that the mycobacterial cell wall surface lipids may play a significant role in this process.
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| 9. |
- Svensson, Erik, 1959, et al.
(författare)
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Impact of immigration on tuberculosis epidemiology in a low-incidence country.
- 2011
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Ingår i: Clinical microbiology and infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 17:6, s. 881-887
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: Mycobacterium tuberculosis strains from 349 patients were isolated in western Sweden during the years 2001-2005. Only 26% of the tuberculosis (TB) patients were born in Sweden. All the others were born in any of 42 different countries; 17% in other European countries, 28% in Africa, 16% in Asia, 11% in the Middle East, and 2% in South America. The mean age of the Swedish-born patients was 67years, while the mean age among the foreign-born patients was 37years. The male/female ratio was 1.6 among the Swedes and 0.9 among those born abroad. Extrapulmonary manifestations of TB were most common among patients born in Africa while lung infections without extrapulmonary manifestations were most common in patients born in Europe, including Sweden. Spoligotyping showed that patients with T or Beijing strains had more pulmonary TB than extrapulmonary TB, while patients with EAI and CAS strains had a high proportion of extrapulmonary TB. The ancestral and/or evolutionary older PGG1 strains were more often isolated from the foreign-born patients than from the Swedish-born patients, who had strains generally being of the evolutionary recent genogroups PGG2/PGG3. We conclude that immigration from countries with a high incidence of TB has a strong impact on the TB epidemiology in western Sweden, a finding that should be taken into account by TB control strategists when developing programmes for eradication of TB in low prevalence settings.
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