| 1. |
- Kondepudi, Kanthi Kiran, et al.
(författare)
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A novel multi-strain probiotic and synbiotic supplement for prevention of Clostridium difficile infection in a murine model.
- 2014
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Ingår i: Microbiology and Immunology. - : Wiley. - 1348-0421 .- 0385-5600. ; 58:10, s. 552-558
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Tidskriftsartikel (refereegranskat)abstract
- The protective effect of a multi-strain probiotic and synbiotic formulation was evaluated in C57BL/6 mice infected with Clostridium difficile (CD) NAP1/027. Antibiotic treated mice were divided into four groups. Group 1, fed with a synbiotic formulation consisting of Lactobacillus plantarum F44, L. paracasei F8, Bifidobacterium breve 46, B. lactis 8:8, galacto-oligosaccharides (GOS), isomalto-oligosaccharides (IMOS) and resistant starch (RS); group 2, fed with the same four probiotic strains as in group 1; group 3, fed with the same prebiotic supplements as mentioned in group 1 for seven days before CD infection and group 4, the control group, was antibiotic treated and infected with NAP1/027 strain. Faeces and caecal contents were collected for microbial cell viability, quantitative PCR (qPCR), toxin analyses and histopathology. Synbiotics and probiotics fed mice showed a significant increase of total bifidobacteria (P < 0.05). Total lactobacilli count was increased in group 1. The caecal toxins were negative in group 2 mice, and one sample each from group 1 and 3 was positive. qPCR of caecal content showed significant reduction in NAP1/027 DNA copies in group 1-2 and significantly higher numbers of B. breve 46, L. plantarum F44 and L. paracasei F8 in group 1 and 2 (P < 0.05) but much less pronounced in group 3-4. This study demonstrated that the newly developed synbiotic or multi-strain probiotic formulation conferred protection against NAP1/027 infection in C57BL/6 mice. This holds promising to conduct future human studies.
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| 2. |
- Rasmussen, Gunlög, et al.
(författare)
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Caspase-1 Inflammasome Activity in Patients with Staphylococcus aureus Bacteremia
- 2019
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Ingår i: Microbiology and immunology. - : Wiley-Blackwell Publishing Inc.. - 0385-5600 .- 1348-0421. ; 63:12, s. 487-499
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Tidskriftsartikel (refereegranskat)abstract
- The inflammasome is a multiprotein complex that mediates caspase-1 activation with subsequent maturation of the pro-inflammatory cytokines IL-1β and IL-18. The NLRP3 inflammasome is known to be activated by Staphylococcus aureus, one of the leading causes of bacteremia worldwide. Inflammasome activation and regulation in response to bacterial infection have been found to be of importance for a balanced host immune response. However, inflammasome signaling in vivo in humans initiated by S. aureus is currently sparsely studied. The present study therefore aimed to investigate NLRP3 inflammasome activity in 20 S. aureus bacteremia patients, by repeated measurement during the first week of bacteremia, compared with controls. Caspase-1 activity was measured in monocytes and neutrophils by flow cytometry detecting FLICA (Fluorescent Labelled Inhibitor of Caspase-1), while IL-1β and IL-18 was measured by Luminex and ELISA, respectively. As a measure of inflammasome priming, mRNA expression of NLRP3, CASP1 (pro-caspase-1) and IL1B (pro-IL-1β) was analyzed by qPCR. We found induced caspase-1 activity in innate immune cells with subsequent release of IL-18 in patients during the acute phase of bacteremia, indicating activation of the inflammasome. There was substantial inter-individual variation in caspase-1 activity between S. aureus bacteremia patients. We also found an altered inflammasome priming with low mRNA levels of NLRP3 accompanied by elevated mRNA levels of IL1B. This increased knowledge of the individual host immune response in S. aureus bacteremia could provide support in the effort to optimize management and treatment of each individual patient.
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| 3. |
- Rasmussen, Gunlög, 1973-, et al.
(författare)
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Expression of HLA-DRA and CD74 mRNA in whole blood during the course of complicated and uncomplicated Staphylococcus aureus bacteremia
- 2017
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Ingår i: Microbiology and immunology. - : Wiley-Blackwell Publishing Asia. - 0385-5600 .- 1348-0421. ; 61:10, s. 442-451
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Tidskriftsartikel (refereegranskat)abstract
- To improve management of Staphylococcus aureus bacteremia (SAB), better understanding of host-pathogen interactions is needed. In vitro studies have shown that S. aureus bacteria induce dose-dependent immunosuppression that is evidenced by reduced expression of major histocompatibility complex (MHC) class II on antigen presenting cells. Thus, the aim of this study was to determine whether expression of the MHC class II-related genes HLA-DRA and CD74 is more greatly reduced in complicated SAB, with its probable higher loads of S. aureus, than in uncomplicated SAB. Adult patients with SAB were prospectively included and blood samples taken on the day of confirmation of SAB (Day 1) and on Days 2, 3, 5 and 7. HLA-DRA and CD74 mRNA expression was determined by quantitative reverse transcription PCR. Sepsis was defined according to the Sepsis-3 classification and SAB was categorized as complicated in patients with deep-seated infection and/or hematogenous seeding. Twenty patients with SAB were enrolled and samples obtained on all assessment days. HLA-DRA and CD74 expression did not differ significantly between patients with SAB and sepsis (n=13) and those without sepsis (n=7) on any assessment day. However, patients with complicated SAB (n=14) had significantly weaker HLA-DRA expression on all five assessment days than patients with uncomplicated SAB (n=6). Additionally, they tended to have weaker CD74 expressions. Neutrophil, monocyte and leukocyte counts did not differ significantly between complicated and uncomplicated SAB. In conclusion, patients with complicated SAB show weaker HLA-DRA expression than those with uncomplicated SAB during the first week of bacteremia.
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| 4. |
- Holmberg, Rebecka, et al.
(författare)
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Antiviral treatments reduce severity of diabetes in Ljungan virus-infected CD-1 mice and delay onset in diabetes-prone BB rats
- 2009
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Ingår i: Microbiology and immunology. - : Wiley. - 0385-5600 .- 1348-0421. ; 53:10, s. 567-572
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Tidskriftsartikel (refereegranskat)abstract
- The effects of LV in two different species, CD-1 mice, without a genetic disposition for diabetes, and BB rats prone to T1D were examined. Male CD-1 mice that had been exposed to LV in utero developed a type 2-like diabetes with increased blood glucose, insulin levels and epididymal fat at the age of 10-15 weeks. Combination therapy including LV-antiserum and an antiviral drug, Pleconaril, significantly reduced the levels of blood glucose and insulin and the amount of abdominal fat. In BB rats, LV has been found in both prediabetic- and diabetic diabetes-prone rats, as well as in diabetes-resistant rats. To evaluate whether the presence of LV has any influence on the onset of T1D, prediabetic BB rats were treated with an antiserum against LV or a combination of the antiviral drugs Pleconaril and Ribavirin. In the group treated with antiviral drugs, the onset was significantly delayed. These results indicate that the presence of LV can be involved in the pathogenesis of diabetes in these animal models.
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| 5. |
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| 6. |
- Härtlova, Anetta, et al.
(författare)
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Membrane rafts: a potential gateway for bacterial entry into host cells.
- 2010
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Ingår i: Microbiology and immunology. - : Wiley. - 0385-5600 .- 1348-0421. ; 54:4, s. 237-45
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Forskningsöversikt (refereegranskat)abstract
- Pathogenic bacteria have developed various mechanisms to evade host immune defense systems. Invasion of pathogenic bacteria requires interaction of the pathogen with host receptors, followed by activation of signal transduction pathways and rearrangement of the cytoskeleton to facilitate bacterial entry. Numerous bacteria exploit specialized plasma membrane microdomains, commonly called membrane rafts, which are rich in cholesterol, sphingolipids and a special set of signaling molecules which allow entry to host cells and establishment of a protected niche within the host. This review focuses on the current understanding of the raft hypothesis and the means by which pathogenic bacteria subvert membrane microdomains to promote infection.
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| 7. |
- Jonsson, Nina, et al.
(författare)
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Real-time polymerase chain reaction as a rapid and efficient alternative to estimation of picornavirus titers by tissue culture infectious dose 50% or plaque forming units
- 2009
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Ingår i: Microbiology and immunology. - : Wiley. - 0385-5600 .- 1348-0421. ; 53:3, s. 149-154
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Tidskriftsartikel (refereegranskat)abstract
- Quantification of viral infectious units is traditionally measured by methods based on forming plaques in semisolid media (PFU) or endpoint dilution of a virus-containing solution (TCID(50)), methods that are laborious, time-consuming and take on average 3-7 days to carry out. Quantitative real-time PCR is an established method to quantify nucleic acids at high accuracy and reproducibility, routinely used for virus detection and identification. In the present study, a procedure was developed using a two-step real-time PCR and the SYBR Green detection method to study whether there are correlations between TCID(50)/ml, PFU/ml and Ct values generated by real-time PCR enabling rapid and efficient calculation of titer equivalents when working with viruses in the research laboratory. In addition, an external standard with known concentrations was included using in vitro transcribed viral RNA, thus allowing the calculation of the amount of RNA copies needed for various applications (i.e. per plaque or TCID(50)).The results show that there is a correlation between the three quantification methods covering a wide range of concentration of viruses. Furthermore, a general regression line between TCID(50) and Ct values was obtained for all viruses included in the study, which enabled recording titer equivalents using real-time PCR. Finally, by including an external standard, the amount of RNA genomes generating one TCID(50) or PFU for each enterovirus serotype included was determined.
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