lnu.sePublications
Change search
Refine search result
1 - 20 of 20
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Axelsson Olsson, Diana
    Kalmar County Hospital.
    Acanthamoebae polyphaga – en trojansk häst vid campylobacter-infektion?2004Conference paper (Refereed)
  • 2. Axelsson Olsson, Diana
    Acanthamoebae-Campylobacter co-culture as a novel method for enrichment of Campylobacter species2007Conference paper (Refereed)
  • 3. Axelsson Olsson, Diana
    Campylobacter jejuni acid tolerance increases when co-incubated with amoebae2009Conference paper (Refereed)
  • 4.
    Axelsson Olsson, Diana
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Campylobacters and protozoans: the missing link in the epidemiology of campylobacteriosis?2006Conference paper (Refereed)
  • 5.
    Axelsson Olsson, Diana
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Interaktioner mellan bakterier och protozoer i vattenmiljö, ett dolt hot?2014Conference paper (Refereed)
  • 6.
    Axelsson Olsson, Diana
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Interaktioner mellan bakterier och protozoer i vattenmiljö, ett dolt hot?2012Conference paper (Refereed)
  • 7.
    Axelsson Olsson, Diana
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Survival of Campylobacter jejuni within Acanthamoeba polyphaga; a possible transmission route?2004Conference paper (Refereed)
  • 8.
    Axelsson Olsson, Diana
    et al.
    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.
    Haemig, Paul D
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Brudin, Lars
    Olsen, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Acanthamoeba-Campylobacter coculture as a novel method for enrichment of Campylobacter species2007In: Applied and Environmental Microbiology, Vol. 73, no 21, p. 6864-6869Article in journal (Refereed)
    Abstract [en]

    In this study, we present a novel method to isolate and enrich low concentrations of Campylobacter pathogens. This method, Acanthamoeba-Campylobacter coculture (ACC), is based on the intracellular survival and multiplication of Campylobacter species in the free-living protozoan Acanthamoeba polyphaga. Four of the Campylobacter species relevant to humans and livestock, Campylobacter jejuni, C. coli, C. lari, and C. hyointestinalis, were effectively enriched by the coculture method, with growth rates comparable to those observed in other Campylobacter enrichment media. Studying six strains of C. jejuni isolated from different sources, we found that all of the strains could be enriched from an inoculum of fewer than 10 bacteria. The sensitivity of the ACC method was not negatively affected by the use of Campylobacter-selective antibiotics in the culture medium, but these were effective in suppressing the growth of seven different bacterial species added at a concentration of 10(4) CFU/ml of each species as deliberate contamination. The ACC method has advantages over other enrichment methods as it is not dependent on a microaerobic milieu and does not require the use of blood or other oxygen-quenching agents. Our study found the ACC method to be a promising tool for the enrichment of Campylobacter species, particularly from water samples with low bacterial concentrations.

  • 9.
    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.
    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
    University of Kalmar, School of Pure and Applied Natural Sciences.
    A simple method for long-term storage Acanthamoeba species2009In: Parasitology Research, ISSN 0932-0113, E-ISSN 1432-1955, Vol. 104, no 4, p. 935-937Article in journal (Refereed)
    Abstract [en]

    We present a novel and simple technique for storing live Acanthamoeba for long periods of time. The amoebae are maintained at refrigerator temperatures in a peptone-yeast extract-glucose (PYG) medium normally used for cultivation. Using this method, we obtained survival rates of at least 4 years for Acanthamoeba polyphaga and 3 years for Acanthamoeba castellanii and Acanthamoeba rhysodes. Advantages of this storage method are: (1) it is quick and simple, (2) inexpensive, (3) does not require encystment before storage, (4) resuscitation of cysts can be achieved within a week of culture in PYG medium at 27A degrees C, and does not require co-culture with bacteria or any special equipment.

  • 10.
    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.

  • 11.
    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)
  • 12.
    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.

  • 13.
    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.

  • 14.
    Axelsson Olsson, Diana
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Waldenström, Jonas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Broman, Tina
    Olsen, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Holmberg, M
    The protozoan Acanthamoeba polyphaga as a potential reservoir for Campylobacter jejuni2005In: Applied and environmental microbiology, Vol. 71 (2), p. 987-992Article in journal (Refereed)
  • 15.
    Griekspoor, Petra
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Olofsson, Jenny
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Axelsson Olsson, Diana
    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.
    Olsen, Björn
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Multilocus Sequence Typing and FlaA Sequencing Reveal the Genetic Stability of Campylobacter jejuni Enrichment during Coculture with Acanthamoeba polyphaga2013In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 79, no 7, p. 2477-2479Article in journal (Refereed)
    Abstract [en]

    Low concentrations of Campylobacter jejuni cells in environmental samples make them difficult to study with conventional culture methods. Here, we show that enrichment by amoeba cocultures works well with low-concentration samples and that this method can be combined with molecular techniques without loss of genetic specificity.

  • 16.
    Olofsson, Jenny
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Uppsala University.
    Axelsson Olsson, Diana
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Brudin, Lars
    Kalmar County Hospital ; Linköping University.
    Olsen, Björn
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Uppsala University.
    Ellström, Patrik
    Uppsala University.
    Campylobacter jejuni Actively Invades the Amoeba Acanthamoeba polyphaga and Survives within Non Digestive Vacuoles2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 11, article id e78873Article in journal (Refereed)
    Abstract [en]

    The Gram-negative bacterium Campylobacter jejuni is able to enter, survive and multiply within the free living amoeba Acanthamoeba polyphaga, but the molecular mechanisms behind these events are still unclear. We have studied the uptake and intracellular trafficking of viable and heat killed bacterial cells of the C. jejuni strain 81-176 in A. polyphaga. We found that viable bacteria associated with a substantially higher proportion of Acanthamoeba trophozoites than heat killed bacteria. Furthermore, the kinetics of internalization, the total number of internalized bacteria as well as the intracellular localization of internalized C. jejuni were dramatically influenced by bacterial viability. Viable bacteria were internalized at a high rate already after 1 h of co-incubation and were observed in small vacuoles tightly surrounding the bacteria. In contrast, internalization of heat killed C. jejuni was low at early time points and did not peak until 96 h. These cells were gathered in large spacious vacuoles that were part of the degradative pathway as determined by the uptake of fluorescently labeled dextran. The amount of heat killed bacteria internalized by A. polyphaga did never reach the maximal amount of internalized viable bacteria. These results suggest that the uptake and intracellular survival of C. jejuni in A. polyphaga is bacterially induced.

  • 17.
    Olofsson, Jenny
    et al.
    Uppsala University.
    Griekspoor, Petra
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Olsen, Björn
    Uppsala University.
    Ellström, Patrik
    Uppsala University.
    Axelsson Olsson, Diana
    Linnaeus University, Faculty of Health and Life Sciences, Department of Medicine and Optometry. Uppsala University.
    The abundant free-living amoeba, Acanthamoeba polyphaga, increases the survival of Campylobacter jejuni in milk and orange juice2015In: Infection Ecology & Epidemiology, ISSN 2000-8686, E-ISSN 2000-8686, Vol. 5, article id 28675Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Campylobacter jejuni is a common cause of human bacterial diarrhea in most parts of the world. Most C. jejuni infections are acquired from contaminated poultry, milk, and water. Due to health care costs and human suffering, it is important to identify all possible sources of infection. Unpasteurized milk has been associated with several outbreaks of C. jejuni infection. Campylobacter has been identified on fresh fruit, and other gastrointestinal pathogens such as Salmonella, E. coli O157:H7 and Cryptosporidium have been involved in fruit juice outbreaks. C. jejuni is sensitive to the acidic environment of fruit juice, but co-cultures with the amoeba, Acanthamoeba polyphaga, have previously been shown to protect C. jejuni at low pH.

    METHODS: To study the influence of A. polyphaga on the survival of C. jejuni in milk and juice, the bacteria were incubated in the two products at room temperature and at 4°C with the following treatments: A) C. jejuni preincubated with A. polyphaga before the addition of product, B) C. jejuni mixed with A. polyphaga after the addition of product, and C) C. jejuni in product without A. polyphaga. Bacterial survival was assessed by colony counts on blood agar plates.

    RESULTS: Co-culture with A. polyphaga prolonged the C. jejuni survival both in milk and juice. The effect of co-culture was most pronounced in juice stored at room temperature. On the other hand, A. polyphaga did not have any effect on C. jejuni survival during pasteurization of milk or orange juice, indicating that this is a good method for eliminating C. jejuni in these products.

    CONCLUSION: Amoebae-associated C. jejuni in milk and juice might cause C. jejuni infections.

  • 18.
    Olsen, Björn
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Axelsson Olsson, Diana
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Thelin, A
    Weiland, O
    Unexpected high prevalence of IgG-antibodies to hepatitis E virus in Swedish pig farmers and controls2006In: Scandinavian journal of infectious diseases, Vol. 38, no 1, p. 55-58Article in journal (Refereed)
  • 19. Thegerström, J
    et al.
    Marklund, Britt-Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hoffner, S
    Axelsson Olsson, Diana
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Kauppinen, J
    Olsen, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Mycobacterium avium with the bird type IS1245 RFLP profile is commonly found in wild and domestic animals, but rarely in humans2005In: Scandinavian journal of infectious diseases, Vol. 37 (1), p. 15-20Article in journal (Refereed)
  • 20.
    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.

1 - 20 of 20
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf