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  • 1.
    Axelsson Olsson, Diana
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Olofsson, Jenny
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Svensson, Lovisa
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Ellström, Patrik
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Waldenström, Jonas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Olsen, Björn
    Uppsala University Hospital.
    Campylobacter jejuni acid tolerance increases when co-incubated with amoebae2009Conference paper (Refereed)
    Abstract [en]

    Background: Although Campylobacter jejuni is a frequent cause of bacterial gastroenteritis, one of the enigmas is how thisfragile organism can survive the transit through the acid milieu of the stomach. C. jejuni is very sensitive to low pH, but cansurvive in moderately acid environment for short periods of time. We have previously shown that C. jejuni can colonize andeven replicate in different species of amoebas, thereby gaining protection from adverse environments.

    Objectives: We evaluated the effects of hydrochloric acid (HCl) on C. jejuni at various pH and time intervals, to study whetherco-cultivation with amoeba influenced C.jejuni acid tolerance. The setup was chosen to mimic the acidified milieu of the humangastrointestinal tract.

    Methods: Cultures of C. jejuni (CCUG 11284) were co-cultured with Acanthamoeba polyphaga in either PBS or tap wateracidified with HCl to pH 1, 2, 3 and 4. We also evaluated different treatments effect on campylobacter survival, by exposingsome bacterial samples to an acid shock and some to a slower acidification process.

    Results and conclusions: We show that C. jejuni can withstand pH below the normal range of survival, when co-cultured withA. polyphaga. C. jejuni co-cultured with amoebae survived acidified conditions at pH 3 for 20 hours and pH 2 for approximately5 hours. We also found a pH increase during the experiment, which correlated with campylobacter survival. These results pointto an unknown mechanism for C.jejuni to survive at low pH levels. This could be in the form of excretion of pH-increasingsubstances and simultaneous chemotaxic orientation towards a protective host. Our results could give one possible explanationto C. jejuni survival through the low pH of the gastrointestinal tract.

  • 2.
    Axelsson Olsson, Diana
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Olofsson, Jenny
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Svensson, Lovisa
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Griekspoor, Petra
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Ellström, Patrik
    University of Kalmar, School of Pure and Applied Natural Sciences. Uppsala University ; Uppsala University Hospital.
    Waldenström, Jonas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Olsen, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Protozoa as hosts for Campylobacter spp2009Conference paper (Refereed)
  • 3.
    Axelsson Olsson, Diana
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olofsson, Jenny
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Svensson, Lovisa
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Griekspoor, Petra
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Ellström, Patrik
    Clinical Bacteriology, Department of Medical Sciences, Uppsala University and Uppsala University Hospital, SE-751 85 Uppsala, Sweden.
    Olsen, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Amoebae and algae can prolong the survival of Campylobacter species in co-culture2010In: Experimental parasitology, ISSN 0014-4894, E-ISSN 1090-2449, Vol. 126, p. 59-64Article in journal (Refereed)
    Abstract [en]

    Several species of free-living amoebae can cause disease in humans. However, in addition to the direct pathogenicity of e.g. Acanthamoebae and Naegleria species, they are recognized as environmental hosts, indirectly involved in the epidemiology of many pathogenic bacteria. Although several studies have demonstrated intracellular survival of many different bacteria in these species, the extent of such interactions as well as the implications for the epidemiology of the bacterial species involved, are largely unknown and probably underestimated. In this study, we evaluated eight different unicellular eukaryotic organisms, for their potential to serve as environmental hosts for Campylobacter species. These organisms include four amoebozoas (Acanthamoeba polyphaga, Acanthamoeba castellanii, Acanthamoeba rhysodes and Hartmanella vermiformis), one alveolate (Tetrahymena pyriformis), one stramenopile (Dinobryon sertularia), one eugoenozoa (Euglena gracilis) and one heterolobosea (Naegleria americana). Campylobacter spp. including Campylobacter jejuni, Campylobacter coli and Campylobacter lari are the most common cause of gastroenteritis in the western world. Survival and replication of these three species as well as Campylobacter hyointestinalis were assessed in co-cultures with the eukaryotic organisms. Campylobacter spp. generally survived longer in co-cultures, compared to when incubated in the corresponding growth media. The eukaryotic species that best promoted bacterial survival was the golden algae D. sertularia. Three species of amoebozoas, of the genus Acanthamoeba promoted both prolonged survival and replication of Campylobacter spp. The high abundance in lakes, ponds and water distribution networks of these organisms indicate that they might have a role in the epidemiology of campylobacteriosis, possibly contributing to survival and dissemination of these intestinal pathogens to humans and other animals. The results suggest that not only C. jejuni, but a variety of Campylobacter spp. can interact with different eukaryotic unicellular organisms.

  • 4.
    Axelsson Olsson, Diana
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Svensson, Lovisa
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olofsson, Jenny
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Salomon, Paulo
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Ellström, Patrik
    Olsen, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Increase in Acid Tolerance of Campylobacter jejuni through Coincubation with Amoebae2010In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 76, no 13, p. 4194-4200Article in journal (Refereed)
    Abstract [en]

    Campylobacter jejuni is a recognized and common gastrointestinal pathogen in most parts of the world. Human infections are often food borne, and the bacterium is frequent among poultry and other food animals. However, much less is known about the epidemiology of C. jejuni in the environment and what mechanisms the bacterium depends on to tolerate low pH. The sensitive nature of C. jejuni stands in contrast to the fact that it is difficult to eradicate from poultry production, and even more contradictory is the fact that the bacterium is able to survive the acidic passage through the human stomach. Here we expand the knowledge on C. jejuni acid tolerance by looking at protozoa as a potential epidemiological pathway of infection. Our results showed that when C. jejuni cells were coincubated with Acanthamoeba polyphaga in acidified phosphate-buffered saline (PBS) or tap water, the bacteria could tolerate pHs far below those in their normal range, even surviving at pH 4 for 20 h and at pH 2 for 5 h. Interestingly, moderately acidic conditions (pH 4 and 5) were shown to trigger C. jejuni motility as well as to increase adhesion/internalization of bacteria into A. polyphaga. Taken together, the results suggest that protozoa may act as protective hosts against harsh conditions and might be a potential risk factor for C. jejuni infections. These findings may be important for our understanding of C. jejuni passage through the gastrointestinal tract and for hygiene practices used in poultry settings.

  • 5.
    Bonnedahl, Jonas
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Kalmar County Hospital.
    Stedt, Johan
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Svensson, Lovisa
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Drobni, Mirva
    Uppsala University.
    Olsen, Björn
    Uppsala University.
    Comparison of Extended-Spectrum beta-Lactamase (ESBL) CTX-M Genotypes in Franklin Gulls from Canada and Chile2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 10, article id e0141315Article in journal (Refereed)
    Abstract [en]

    Migratory birds have been suggested to contribute to long-distance dispersal of antimicrobial resistant bacteria, but tests of this hypothesis are lacking. In this study we determined resistance profiles and genotypes of ESBL-producing bacteria in randomly selected Escherichia coli from Franklin's gulls (Leucophaeus pipixcan) at breeding sites in Canada and compared with similar data from the gulls' wintering grounds in Chile. Resistant E. coli phenotypes were common, most notably to ampicillin (30.1%) and cefadroxil (15.1%). Furthermore, 17.0% of the gulls in Canada carried ESBL producing bacteria, which is higher than reported from human datasets from the same country. However, compared to gulls sampled in Chile (30.1%) the prevalence of ESBL was much lower. The dominant ESBL variants in Canada were bla(CTX-M-14) and bla(CTX-M-15) and differed in proportions to the data from Chile. We hypothesize that the observed differences in ESBL variants are more likely linked to recent exposure to bacteria from anthropogenic sources, suggesting high local dissemination of resistant bacteria both at breeding and non-breeding times rather than a significant trans-hemispheric exchange through migrating birds.

  • 6.
    Bunse, Carina
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lundin, Daniel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Karlsson, Christofer M. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Akram, Neelam
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Vila-Costa, Maria
    Centre d’Estudis Avançats de Blanes-CSIC, Spain.
    Palovaara, Joakim
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Svensson, Lovisa
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Holmfeldt, Karin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    González, José M.
    University of La Laguna, Spain.
    Calvo, Eva
    Institut de Ciències del Mar—CSIC, Spain.
    Pelejero, Carles
    Institut de Ciències del Mar—CSIC, Spain.
    Marrasé, Cèlia
    Institut de Ciències del Mar—CSIC, Spain.
    Dopson, Mark
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gasol, Josep
    Institut de Ciències del Mar—CSIC, Spain.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Response of marine bacterioplankton pH homeostasis gene expression to elevated CO22016In: Nature Climate Change, ISSN 1758-678X, E-ISSN 1758-6798, Vol. 6, no 5, p. 483-487Article in journal (Refereed)
    Abstract [en]

    Human-induced ocean acidification impacts marine life. Marine bacteria are major drivers of biogeochemical nutrient cycles and energy fluxes1; hence, understanding their performance under projected climate change scenarios is crucial for assessing ecosystem functioning. Whereas genetic and physiological responses of phytoplankton to ocean acidification are being disentangled2, 3, 4, corresponding functional responses of bacterioplankton to pH reduction from elevated CO2 are essentially unknown. Here we show, from metatranscriptome analyses of a phytoplankton bloom mesocosm experiment, that marine bacteria responded to lowered pH by enhancing the expression of genes encoding proton pumps, such as respiration complexes, proteorhodopsin and membrane transporters. Moreover, taxonomic transcript analysis showed that distinct bacterial groups expressed different pH homeostasis genes in response to elevated CO2. These responses were substantial for numerous pH homeostasis genes under low-chlorophyll conditions (chlorophyll a <2.5 μg l−1); however, the changes in gene expression under high-chlorophyll conditions (chlorophyll a >20 μg l−1) were low. Given that proton expulsion through pH homeostasis mechanisms is energetically costly, these findings suggest that bacterioplankton adaptation to ocean acidification could have long-term effects on the economy of ocean ecosystems.

  • 7. Demirel, Isak
    et al.
    Vumma, Ravi
    Mohlin, Camilla
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Svensson, Lovisa
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Säve, Susanne
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Persson, Katarina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nitric Oxide Activates IL-6 Production and Expression in Human Renal Epithelial Cells2012In: American Journal of Nephrology, ISSN 0250-8095, E-ISSN 1421-9670, Vol. 36, no 6, p. 524-530Article in journal (Refereed)
    Abstract [en]

    Background/Aims: Increased nitric oxide (NO) production or inducible form of NO synthase activity have been documented in patients suffering from urinary tract infection (UTI), but the role of NO in this infection is unclear. We investigated whether NO can affect the host response in human renal epithelial cells by modulating IL-6 production and mRNA expression. Methods: The human renal epithelial cell line A498 was infected with a uropathogenic Escherichia coli (UPEC) strain and/or the NO donor DETA/NO. The IL-6 production and mRNA expression were evaluated by ELISA and real-time RT-PCR. IL-6 mRNA stability was evaluated by analyzing mRNA degradation by real-time RT-PCR. Results: DETA/NO caused a significant (p < 0.05) increase in IL-6 production. Inhibitors of p38 MAPK and ERK1/2 signaling, but not JNK, were shown to significantly suppress DETA/NO-induced IL-6 production. UPEC-induced IL-6 production was further increased (by 73 +/- 23%, p < 0.05) in the presence of DETA/NO. The IL-6 mRNA expression increased 2.1 +/- 0.17-fold in response to DETA/NO, while the UPEC-evoked increase was pronounced (20 +/- 4.5-fold). A synergistic effect of DETA/NO on UPEC-induced IL-6 expression was found (33 +/- 7.2-fold increase). The IL-6 mRNA stability studies showed that DETA/NO partially attenuated UPEC-induced degradation of IL-6 mRNA. Conclusions: NO was found to stimulate IL-6 in renal epithelial cells through p38 MAPK and ERK1/2 signaling pathways and also to increase IL-6 mRNA stability in UPEC-infected cells. This study proposes a new role for NO in the host response during UTI by modulating the transcription and production of the cytokine IL-6. Copyright (C) 2012 S. Karger AG, Basel

  • 8.
    Jourdain, Elsa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. INRA, France.
    Gunnarsson, Gunnar
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. Kristianstad University.
    Wahlgren, John
    Karolinska Institutet ; Swedish Institute for Infectious Disease Control.
    Latorre-Margalef, Neus
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bröjer, Caroline
    National Veterinary Institute ; University of Agricultural Sciences.
    Sahlin, Sofie
    Karolinska Institutet ; Swedish Institute for Infectious Disease Control.
    Svensson, Lovisa
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Lundkvist, Åke
    Swedish Institute for Infectious Disease Control.
    Olsen, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. Uppsala University.
    Influenza Virus in a Natural Host, the Mallard: Experimental Infection Data2010In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, no 1, article id e8935Article in journal (Refereed)
    Abstract [en]

    Wild waterfowl, particularly dabbling ducks such as mallards (Anas platyrhynchos), are considered the main reservoir of low-pathogenic avian influenza viruses (LPAIVs). They carry viruses that may evolve and become highly pathogenic for poultry or zoonotic. Understanding the ecology of LPAIVs in these natural hosts is therefore essential. We assessed the clinical response, viral shedding and antibody production of juvenile mallards after intra-esophageal inoculation of two LPAIV subtypes previously isolated from wild congeners. Six ducks, equipped with data loggers that continually monitored body temperature, heart rate and activity, were successively inoculated with an H7N7 LPAI isolate (day 0), the same H7N7 isolate again (day 21) and an H5N2 LPAI isolate (day 35). After the first H7N7 inoculation, the ducks remained alert with no modification of heart rate or activity. However, body temperature transiently increased in four individuals, suggesting that LPAIV strains may have minor clinical effects on their natural hosts. The excretion patterns observed after both reinoculations differed strongly from those observed after the primary H7N7 inoculation, suggesting that not only homosubtypic but also heterosubtypic immunity exist. Our study suggests that LPAI infection has minor clinically measurable effects on mallards and that mallard ducks are able to mount immunological responses protective against heterologous infections. Because the transmission dynamics of LPAIVs in wild populations is greatly influenced by individual susceptibility and herd immunity, these findings are of high importance. Our study also shows the relevance of using telemetry to monitor disease in animals.

  • 9. Poljakovic, Mirjana
    et al.
    Svensson, Lovisa
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Persson, Katarina
    University of Kalmar, School of Pure and Applied Natural Sciences.
    The influence of uropathogenic Escherichia coli and proinflammatory cytokines on the inducible nitric oxide synthase response in human kidney epithelial cells2005In: The journal of urology, Vol. 173 (3), p. 1000-1003Article in journal (Refereed)
  • 10.
    Svensson, Lovisa
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Nitric oxide and bacteria-host interactions in Escherichia coli urinary tract infection2008Doctoral thesis, comprehensive summary (Other academic)
  • 11.
    Svensson, Lovisa
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Marklund, Britt-Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Pojakovic, M
    Persson, Katarina
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Uropathogenic Escherichia coli show increased tolerance to nitric oxide - significance of flavohemoglobin and flavorubredoxin2006In: Nitric oxide : biology and chemistry 14 (4), 2006Conference paper (Refereed)
  • 12.
    Svensson, Lovisa
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Marklund, Britt-Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Poljakovic, Mirjana
    Persson, Katarina
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Uropathogenic Escherichia coli and tolerance to nitric oxide: The role of flavohemoglobin2006In: The journal of urology, Vol. 175 (2), p. 749-753Article in journal (Refereed)
  • 13.
    Svensson, Lovisa
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Mohlin, Camilla
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Persson, Katarina
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Upregulation of Heme Oxygenase-1 as a Host Mechanism for Protection Against Nitric Oxide–induced Damage in Human Renal Epithelial Cells2009In: Urology, ISSN 0090-4295, E-ISSN 1527-9995, Vol. 73, no 5, p. 749-753Article in journal (Refereed)
    Abstract [en]

    ObjectivesTo examine whether urinary tract infection–associated stimuli could regulate heme oxygenase-1 (HO-1) expression and to asses the significance of HO-1 in protecting urinary tract epithelial cells against nitric oxide (NO)-induced damage.

    MethodsHeme oxygenase-1 expression was investigated in the human renal epithelial cell line A498 in response to the uropathogenic Escherichia coli (UPEC) strain IA2, the NO-donor DETA/NONOate (DETA/NO), and proinflammatory cytokines (interleukin-1β, tumor necrosis factor-α, and interferon-γ) using reverse transcriptase polymerase chain reaction and Western blot analysis. Cell viability was examined by the trypan blue exclusion test and light microscopy.

    ResultsThe HO-1 inducer hemin and DETA/NO increased HO-1 expression in A498 cells, and glutathione depletion further increased HO-1 expression in response to DETA/NO and hemin. Stimulation with a UPEC strain or cytokines did not upregulate HO-1 expression. The cytokines induced inducible NO synthase expression and caused an increase in nitrite production. Hemin significantly decreased cytokine-induced NO production (P <0.001). DETA/NO decreased the cell viability by approximately 75%, but hemin was able to attenuate DETA/NO-induced cell damage.

    ConclusionsThe expression of HO-1 increased in human renal epithelial cells in response to NO, and the expression was further enhanced in glutathione-depleted cells. The bacteria per se or proinflammatory cytokines were not able to upregulate HO-1. Heme oxygenase-1 protects the cells against NO by feedback inhibition of NO production and by decreasing cell damage.

  • 14.
    Svensson, Lovisa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Poljakovic, Mirjana
    Karolinska Institutet.
    Säve, Susanne
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Gilberthorpe, Nicola
    University of Sheffield, UK.
    Schön, Thomas
    Kalmar County Hospital.
    Strid, Sigge
    Stensö Health Center, Kalmar County Council.
    Corker, Hazel
    University of Sheffield, UK.
    Poole, Robert K.
    University of Sheffield, UK.
    Persson, Katarina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. Örebro University.
    Role of flavohemoglobin in combating nitrosative stress in uropathogenic Escherichia coli – implications for urinary tract infection2010In: Microbial Pathogenesis, ISSN 0882-4010, E-ISSN 1096-1208, Vol. 49, no 3, p. 59-66Article in journal (Refereed)
    Abstract [en]

    During the course of urinary tract infection (UTI) nitric oxide (NO) is generated as part of the host response. This study investigates the significance of the NO-detoxifying enzyme flavohemoglobin (Hmp) in protection of uropathogenic Escherichia coli (UPEC) against nitrosative stress. An hmp (J96Δhmp) knockout mutant of UPEC strain J96 was constructed using single-gene deletion. The viability of J96Δhmp was significantly reduced (P < 0.001) compared to the wild-type strain after exposure to the NO-donor DETA/NO. The NO consumption in J96Δhmp was significantly (P < 0.001) impaired compared to J96wt. Screening UPEC isolates from patients with UTI revealed increased hmp expression in all patients. In a competition-based mouse model of UTI, the hmp mutant strain was significantly (P < 0.05) out-competed by the wild-type strain. This study demonstrates, for the first time, that Hmp contributes to the protection of UPEC against NO-mediated toxicity in vitro. In addition, hmp gene expression occurs in UPEC isolates from the infected human urinary tract and UPEC that were hmp-deficient had a reduced ability to colonize the mouse urinary tract. Taken together the results suggest that NO detoxification by Hmp may be a fitness advantage factor in UPEC, and a potentially interesting target for development of novel treatment concepts for UTI.

  • 15.
    Svensson, Lovisa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Säve, Susanne
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Persson, Katarina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    The effect of nitric oxide on adherence of P-fimbriated uropathogenic Escherichia coli to human renal epithelial cells2010In: British Journal of Urology, ISSN 0007-1331, E-ISSN 1365-2176, Vol. 105, no 12, p. 1726-1731Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES

    To examine the effect of nitric oxide (NO), an endogenous component of the host defence in urinary tract infection, on the adherence of P-fimbriated uropathogenic Escherichia coli (UPEC) to human renal epithelial cells.

    MATERIALS AND METHODS

    Two wild-type UPEC strains (AD110 and IA2) and the P-fimbriated recombinant strain HB101pPIL-75 were used. Bacteria were allowed to adhere to the human renal epithelial cell line A498 and attachment was evaluated in the absence or presence of the NO donor DETA/NONOate (1 mm). Total RNA was extracted from NO-exposed bacteria in static urine cultures, followed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of the papG gene that encodes the P-fimbriae adhesin PapG.

    RESULTS

    Bacterial adherence to A498 cells was fimbriae-dependent and the ability to agglutinate human P1 positive erythrocytes confirmed that the used strains were P-fimbriated. UPEC strains AD110 and IA2 attached by a mean of 8 bacteria/cell and 20 bacteria/cell, respectively. In the presence of DETA/NONOate, the attachment of AD110 and IA2 to A498 cells was significantly reduced by a mean (sem) of 34 (3.9)% and 45 (14)%, respectively. The expression of papG was decreased after DETA/NONOate exposure as shown by semiquantitative RT-PCR.

    CONCLUSION

    NO disrupted functional adhesion of P-fimbriated UPEC to kidney epithelial cells, suggesting that NO-production from epithelial cells in the urinary tract may limit bacterial colonization at the mucosal surface. The reduced adherence may involve transcriptional effects of NO on papG expression, but further studies are needed to establish the underlying mechanisms.

  • 16.
    Waldenström, Jonas
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. Lund University.
    Axelsson Olsson, Diana
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olsen, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. Uppsala University.
    Hasselquist, Dennis
    Lund University.
    Griekspoor, Petra
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Jansson, Lena
    University of Gothenburg.
    Teneberg, Susanne
    University of Gothenburg.
    Svensson, Lovisa
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Ellström, Patrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. Uppsala University.
    Campylobacter jejuni colonization in wild birds: Results from an infection experiment2010In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, no 2, article id e9082Article in journal (Refereed)
    Abstract [en]

    Campylobacter jejuni is a common cause of bacterial gastroenteritis in most parts of the world. The bacterium has a broad host range and has been isolated from many animals and environments. To investigate shedding patterns and putative effects on an avian host, we developed a colonization model in which a wild bird species, the European Robin Erithacus rubecula, was inoculated orally with C. jejuni from either a human patient or from another wild bird species, the Song Thrush Turdus philomelos. These two isolates were genetically distinct from each other and provoked very different host responses. The Song Thrush isolate colonized all challenged birds and colonization lasted 6.8 days on average. Birds infected with this isolate also showed a transient but significant decrease in body mass. The human isolate did not colonize the birds and could be detected only in the feces of the birds shortly after inoculation. European Robins infected with the wild bird isolate generated a specific antibody response to C. jejuni membrane proteins from the avian isolate, which also was cross-reactive to membrane proteins of the human isolate. In contrast, European Robins infected with the human isolate did not mount a significant response to bacterial membrane proteins from either of the two isolates. The difference in colonization ability could indicate host adaptations.

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