| 1. |
- Augustinsson (Nilsdotter-Augustinsson), Åsa, 1962-, et al.
(författare)
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Interaction of staphylococcus epidermidis from infected hip prostheses with neutrophil granulocytes
- 2001
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 33:6, s. 408-412
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on the interaction of Staphylococcus epidermis isolated from granulation tissue covering infected hip prostheses and neutrophil granulocytes. Bacterial strains isolated from normal flora were used as controls. The bacteria were well characterized with routine methods and further characterized with random amplified polymorphic DNA analyses and slime tests. Phagocytosis and chemiluminescence (CL) assays were used in the neutrophil interaction studies. The prostheses strains were ingested to a lesser extent than strains from normal flora (p ≤ 0.001). There was no significant difference between the prostheses strains and the normal flora strains in terms of total CL response. However, the extracellular CL response from the neutrophils was lower in comparison with the normal flora when interacting with the prostheses strains. The results of this study support the notion that S. epidermidis strains isolated from infected hip prostheses have an enhanced capacity to resist phagocytosis and that most of these strains elicit a reduced inflammatory response, measured as the production of extracellular oxidative metabolites from the neutrophils, compared to normal flora.
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| 2. |
- Nilsdotter-Augustinsson, Åsa, 1962-, et al.
(författare)
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Adherence of Staphylococcus epidermidis to extracellular matrix proteins and effects of fibrinogen-bound bacteria on oxidase activity and apoptosis in neutrophils
- 2005
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 113:5, s. 361-373
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus epidermidis often causes foreign-body infections such as those associated with hip prostheses, but the underlying pathogenic mechanisms are not fully understood. We performed spectrophotometry to study the ability of S. epidermidis to bind to immobilised fibrinogen, fibronectin, vitronectin, and collagen. The strains were isolated from infected hip prostheses or from normal flora and the well-known protein-binding strain Staphylococcus aureus Cowan was used as positive control. We also analysed the interaction between neutrophils and a fibrinogen-bound prosthesis-derived strain of S. epidermidisby measuring chemiluminescence to determine the neutrophil oxidative response and binding of annexin V to indicate neutrophil apoptosis. We found that binding of S. epidermidis to extracellular matrix proteins varied under different growth conditions, and that prosthesis isolates adhered better to vitronectin than did strains from normal flora. The oxidative response caused by fibrinogen-bound S. epidermidis was not above the background level, which was in marked contrast to the distinct response induced by fibrinogen-associated S. aureus Cowan. Furthermore, fibrinogen-adhering S. epidermidis retarded neutrophil apoptosis. We conclude that surface-bound S. epidermidis induces only a weak inflammatory response, which in combination with the ability of the adherent bacteria to retard neutrophil apoptosis may contribute to low-grade inflammation and loosening of prostheses.
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| 3. |
- Bäckman, Jenny, 1974-, et al.
(författare)
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Clear-cutting affects the ammonia-oxidising community differently in limed and non-limed coniferous forest soils
- 2004
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Ingår i: Biology and Fertility of Soils. - : Springer Science and Business Media LLC. - 0178-2762 .- 1432-0789. ; 40:4, s. 260-267
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Tidskriftsartikel (refereegranskat)abstract
- The effects of clear-cutting on the ammonia-oxidising bacterial community were studied in the soil of limed and non-limed spruce forest plots located in the central part of southern Sweden. The communities were studied using denaturing gradient gel electrophoresis (DGGE) profiling after polymerase chain reaction (PCR) amplification from total DNA with primers reported to be specific for beta-subgroup ammonia-oxidising bacteria. The bands on the DGGE were sequenced and each unique sequence was interpreted as representing one ammonia-oxidising population. The relative abundance of each population was determined by measuring the fluorescence of the respective DGGE bands. In both limed and non-limed soil, the same two Nitrosospira populations were found, one belonging to cluster 2 (NScl2) and one to cluster 4 (NScl4). However, while NScl4 first appeared a year after the clear-cutting in the non-limed plot, it was present both before and after the cutting in the limed plot. Irrespective of previous liming, clear-cutting caused a shift in the ammonia-oxidiser community, from dominance by the NScl2 population to a community with approximately equal relative abundance of NScl2 and NScl4. In both plots the total size of the community increased after clear-cutting (based on increased DGGE band intensity), most likely due to increased NH4+ availability, but the growth response was faster in the limed plot. Hence, the prior liming increased the responsiveness of the ammonia-oxidisers to the changes caused by cutting. This is the first study to report the effects of clear-cutting on the ammonia-oxidising community, and the results show a clear correlation between increased potential nitrification and a shift in the ammonia-oxidiser community.
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| 4. |
- Carlströmer Berthén, Nellie, et al.
(författare)
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The AxBioTick Study: Borrelia Species and Tick-Borne Encephalitis Virus in Ticks, and Clinical Responses in Tick-Bitten Individuals on the Aland Islands, Finland
- 2023
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Ingår i: Microorganisms. - : MDPI. - 2076-2607. ; 11:5
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Tidskriftsartikel (refereegranskat)abstract
- The AxBioTick Study: Borrelia Species and Tick-Borne Encephalitis Virus in Ticks, and Clinical Responses in Tick-Bitten Individuals on the Aland Islands, Finlandby Nellie Carlströmer Berthén 1,2,*,† , Eszter Tompa 3,† , Susanne Olausson 1,2, Clara Nyberg 1, Dag Nyman 1,2, Malin Ringbom 1,4, Linda Perander 1,4, Joel Svärd 3, Per-Eric Lindgren 3,5, Pia Forsberg 3, Peter Wilhelmsson 3,5,‡, Johanna Sjöwall 3,6,‡ and Marika Nordberg 1,4,‡ 1Borrelia Research Group of the Aland Islands, 22100 Mariehamn, The Aland Islands, Finland2Bimelix AB, 22100 Mariehamn, The Aland Islands, Finland3Department of Biomedical and Clinical Sciences, Division of Inflammation and Infection, Linkoping University, 581 83 Linkoping, Sweden4The Aland Islands Healthcare Services, 22100 Mariehamn, The Aland Islands, Finland5Clinical Microbiology, Laboratory Medicine, County Hospital Ryhov, 551 85 Jonkoping, Sweden6Department of Infectious Diseases, Vrinnevi Hospital, 603 79 Norrkoping, Sweden*Author to whom correspondence should be addressed.†These authors contributed equally to the study.‡These authors contributed equally to the study.Microorganisms 2023, 11(5), 1100; https://doi.org/10.3390/microorganisms11051100Received: 30 March 2023 / Revised: 17 April 2023 / Accepted: 19 April 2023 / Published: 22 April 2023(This article belongs to the Special Issue Research on Ticks and Tick-Borne Pathogens)Download Browse Figures Versions NotesArticle Views585 AbstractThe AxBioTick study was initiated to investigate the prevalence of ticks and tick-borne pathogens and their impact on antibody and clinical responses in tick-bitten individuals on the Aland Islands. This geographical area is hyperendemic for both Lyme borreliosis (LB) and Tick-borne encephalitis (TBE). Blood samples and ticks were collected from 100 tick-bitten volunteers. A total of 425 ticks was collected, all determined to Ixodes ricinus using molecular tools. Of them 20% contained Borrelia species, of which B. garinii and B. afzelii were most common. None contained the TBE virus (TBEV). Blood samples were drawn in conjunction with the tick bite, and eight weeks later. Sera were analyzed for Borrelia- and TBEV-specific antibodies using an ELISA and a semiquantitative antibody assay. In total 14% seroconverted in Borrelia C6IgG1, 3% in TBEV IgG, and 2% in TBEV IgM. Five participants developed clinical manifestations of LB. The high seroprevalence of both Borrelia (57%) and TBEV (52%) antibodies are likely attributed to the endemic status of the corresponding infections as well as the TBE vaccination program. Despite the similar prevalence of Borrelia spp. detected in ticks in other parts of Europe, the infection rate in this population is high. The AxBioTick study is continuing to investigate more participants and ticks for co-infections, and to characterize the dermal immune response following a tick bite.
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| 5. |
- Eskeland, Sveinung, et al.
(författare)
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Temporal patterns of gene expression in response to inoculation with a virulent Anaplasma phagocytophilum strain in sheep
- 2023
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Ingår i: Scientific Reports. - : Springer. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to characterize the gene expression of host immune- and cellular responses to a Norwegian virulent strain of Anaplasma phagocytophilum, the cause of tick-borne fever in sheep. Ten sheep were intravenously inoculated with a live virulent strain of A. phagocytophilum. Clinical-, observational-, hematological data as well as bacterial load, flow cytometric cell count data from peripheral blood mononuclear cells and host's gene expression post infection was analysed. The transcriptomic data were assessed for pre-set time points over the course of 22 days following the inoculation. Briefly, all inoculated sheep responded with clinical signs of infection 3 days post inoculation and onwards with maximum bacterial load observed on day 6, consistent with tick-borne fever. On days, 3-8, the innate immune responses and effector processes such as IFN1 signaling pathways and cytokine mediated signaling pathways were observed. Several pathways associated with the adaptive immune responses, namely T-cell activation, humoral immune responses, B-cell activation, and T- and B-cell differentiation dominated on the days of 8, 10 and 14. Flow-cytometric analysis of the PBMCs showed a reduction in CD4+CD25+ cells on day 10 and 14 post-inoculation and a skewed CD4:CD8 ratio indicating a reduced activation and proliferation of CD4-T-cells. The genes of important co-stimulatory molecules such as CD28 and CD40LG, important in T- and B-cell activation and proliferation, did not significantly change or experienced downregulation throughout the study. The absence of upregulation of several co-stimulatory molecules might be one possible explanation for the low activation and proliferation of CD4-T-cells during A. phagocytophilum infection, indicating a suboptimal CD4-T-cell response. The upregulation of T-BET, EOMES and IFN-γ on days 8-14 post inoculation, indicates a favoured CD4 Th1- and CD8-response. The dynamics and interaction between CD4+CD25+ and co-stimulatory molecules such as CD28, CD80, CD40 and CD40LG during infection with A. phagocytophilum in sheep needs further investigation in the future.
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| 6. |
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| 7. |
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| 8. |
- Hermansson, Anna, et al.
(författare)
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Quantification of ammonia-oxidising bacteria in limed and non-limed acidic coniferous forest soil using real-time PCR
- 2004
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 36:12, s. 1935-1941
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Tidskriftsartikel (refereegranskat)abstract
- Ammonia-oxidising bacteria (AOB) in limed and non-limed acidic coniferous forest soil were investigated using real-time PCR. Two sites in southern Sweden were studied, 244 Åled and Oxafällan. The primers and probe used earlier appeared to be specific to the 16S rRNA gene of AOB belonging to the β-subgroup of the Proteobacteria [Appl. Environ. Microbiol. 67 (2001) 972]. Plots treated with two different doses of lime, 3 or 6 t ha-1, were compared with non-limed control plots on two occasions during a single growing season. Three different soil depths were analysed to elucidate possible differences in the density of their AOB communities. The only clear effect of liming on the AOB was recorded in the beginning of the growing season at 244 Åled. In samples taken in April from this site, the numbers of AOB were higher in the limed plots than in the control plots. At the end of the growing season the AOB communities were all of a similar size in the different plots at both sites, irrespective of liming. The number of AOB, determined using real-time PCR, ranged between 6×106 and 1×109 cells g-1 soil (dw) at the two sites, and generally decreased with increasing soil depth. The results showed no correlation between community density and potential nitrification. This may indicate a partly inactive AOB community. Furthermore, more than 107 cells g-1 soil (dw) were recorded using real-time PCR in the control plot at 244 Åled, although Bäckman et al. [Soil Biol. Biochem. 35 (2003) 1337] detected no AOB like sequences in the same plots using PCR followed by DGGE. Taken together our results strongly suggest that the primers and probe set used are not well suited for quantifying AOB in acidic forest soils, which is probably due to an insufficient specificity. This shows that it is extremely important to re-evaluate any primers and probe set when used in a new environment. Consideration should be given to the specificity and sensitivity, both empirically and using bioinformatic tools.
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| 9. |
- Hermansson, A, et al.
(författare)
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Quantification of ammonia-oxidizing bacteria in arable soil by real-time PCR
- 2001
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 67:2, s. 972-976
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Tidskriftsartikel (refereegranskat)abstract
- Real-time PCR was used to quantify populations of ammonia-oxidizing bacteria representing the ▀ subdivision of the class Proteobacteria in samples of arable soil, both nitrogen fertilized and unfertilized, from Mellby, Sweden. Primers and probes targeting a 16S ribosomal DNA region of the ammonia-oxidizing bacteria were designed and used. In the fertilized soil there were ~6.2 x 107 ammonia-oxidizing bacteria per g of soil, three times more than the number of bacteria in the unfertilized soil. The lyric efficiency of bead beating in these soils was investigated by using populations of free or loosely attached bacteria, bacteria tightly bound to particles, and bacteria in nonfractionated samples. The shapes of the curves generated in these tests showed that the concentration of template DNA released at various times remained constant after 10 to 100 s of bead beating.
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| 10. |
- Hoffman, Tove, et al.
(författare)
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A divergent Anaplasma phagocytophilum variant in an Ixodes tick from a migratory bird; Mediterranean basin
- 2020
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Ingår i: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686 .- 2000-8686. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Anaplasma phagocytophilum (AP) has vast geographical and host ranges and causes disease in humans and domesticated animals. We investigated the role of northward migratory birds in the dispersal of tick-borne AP in the African-Western Palearctic.Ticks were collected from northward migratory birds trapped during spring migration of 2010 at two localities in the central Mediterranean Sea. AP DNA was detected by PCR (gltA and 16S rRNA) and variant determination was performed using ankA sequences.In total, 358 ticks were collected. One of 19 ticks determined as Ixodes was confirmed positive for AP DNA. The tick was collected from a woodchat shrike (Lanius senator senator) trapped in Greece, and molecularly determined to belong to the I. ricinus complex and sharing highest (95%) 16S RNA sequence identity to I. gibbosus. The ankA AP sequence exhibited highest similarity to sequences from rodents and shrews (82%) and ruminants (80%). Phylogenetic analyses placed it convincingly outside other clades, suggesting that it represents a novel AP variant.The divergent Ixodes species harboring a novel AP variant could either indicate an enzootic cycle involving co-evolution with birds, or dissemination from other regions by avian migration. None of the 331 Hyalomma marginatum sensu lato ticks, all immature stages, were positive for AP DNA, lending no evidence for the involvement of Hyalomma ticks transported by birds in the ecology of AP.
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