lnu.sePublications
Change search
Refine search result
1 - 12 of 12
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • 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
    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.

  • 2.
    Ellström, Patrik
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Latorre-Margalef, Neus
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Griekspoor, Petra
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Waldenström, Jonas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Olofsson, Jenny
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Wahlgren, John
    Ctr Microbiol Preparedness KCB, Swedish Inst Infect Dis Control SMI, SE-17182 Solna, Sweden.
    Olsen, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Sampling for low-pathogenic avian influenza A virus in wild Mallard ducks: Oropharyngeal versus cloacal swabbing2008In: Vaccine, ISSN 0264-410X, E-ISSN 1873-2518, Vol. 26, no 35, p. 4414-4416Article in journal (Refereed)
  • 3.
    Griekspoor, Petra
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Colles, Frances M.
    Mccarthy, Noel D.
    Hansbro, Philip M.
    Ashhurst-Smith, Chris
    Olsen, Björn
    Department of Medical Sciences, Uppsala University.
    Hasselquist, Dennis
    Maiden, Martin C. J.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Marked host specificity and lack of phylogeographic population structure of Campylobacter jejuni in wild birds2013In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 22, no 5, p. 1463-1472Article in journal (Refereed)
    Abstract [en]

    Zoonotic pathogens often infect several animal species, and gene flow among populations infecting different host species may affect the biological traits of the pathogen including host specificity, transmissibility and virulence. The bacterium Campylobacter jejuni is a widespread zoonotic multihost pathogen, which frequently causes gastroenteritis in humans. Poultry products are important transmission vehicles to humans, but the bacterium is common in other domestic and wild animals, particularly birds, which are a potential infection source. Population genetic studies of C. jejuni have mainly investigated isolates from humans and domestic animals, so to assess C. jejuni population structure more broadly and investigate host adaptation, 928 wild bird isolates from Europe and Australia were genotyped by multilocus sequencing and compared to the genotypes recovered from 1366 domestic animal and human isolates. Campylobacter jejuni populations from different wild bird species were distinct from each other and from those from domestic animals and humans, and the host species of wild bird was the major determinant of C. jejuni genotype, while geographic origin was of little importance. By comparison, C. jejuni differentiation was restricted between more phylogenetically diverse farm animals, indicating that domesticated animals may represent a novel niche for C. jejuni and thereby driving the evolution of those bacteria as they exploit this niche. Human disease is dominated by isolates from this novel domesticated animal niche.

  • 4.
    Griekspoor, Petra
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Engvall, Eva
    Olsen, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Multilocus sequence typing of Campylobacter jejuni from broilers2010In: Veterinary Microbiology, ISSN 0378-1135, E-ISSN 1873-2542, Vol. 140, p. 180-185Article in journal (Refereed)
    Abstract [en]

    Campylobacter jejuni isolates from a national Swedish Campylobacter monitoring in broilers were characterized by multilocus sequencing typing (MLST) in order to study the genetic diversity of this bacterial population. Isolates were initially characterized by pulsed-field gel electrophoresis (PFGE). One hundred were chosen for MLST genotyping. PFGE identified 69 distinct types compared to 44 different sequence types (STs) identified with MLST. Eighteen STs had not been described previously, while the remaining 26 STs were assigned to previously known clonal complexes. The majority of isolates were of genotypes noted in broilers and in humans in earlier studies. However, three clonal complexes, ST-206 complex, ST-677 complex and ST-1034 complex, previously associated with wild bird and environmental samples, were among the genotypes found. This study shows that most of the Swedish broiler isolates were of genotypes noted as common in broilers. However, it also highlights the potential influence of environmental sources on the broiler C jejuni genotypes.

  • 5.
    Griekspoor, Petra
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hansbro, Philip M.
    University of Newcastle, Australia.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Uppsala University.
    Olsen, Björn
    Uppsala University.
    Campylobacter jejuni sequence types show remarkable spatial and temporal stability in Blackbirds2015In: Infection Ecology & Epidemiology, ISSN 2000-8686, E-ISSN 2000-8686, Vol. 5, article id 28383Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The zoonotic bacterium Campylobacter jejuni has a broad host range but is especially associated with birds, both domestic and wild. Earlier studies have indicated thrushes of the genus Turdus in Europe to be frequently colonized with C. jejuni, and predominately with host-associated specific genotypes. The European Blackbird Turdus merula has a large distribution in Europe, including some oceanic islands, and was also introduced to Australia by European immigrants in the 1850s.

    METHODS: The host specificity and temporal stability of European Blackbird C. jejuni was investigated with multilocus sequence typing in a set of isolates collected from Sweden, Australia, and The Azores.

    RESULTS: Remarkably, we found that the Swedish, Australian, and Azorean isolates were genetically highly similar, despite extensive spatial and temporal isolation. This indicates adaptation, exquisite specificity, and stability in time for European Blackbirds, which is in sharp contrast with the high levels of recombination and mutation found in poultry-related C. jejuni genotypes.

    CONCLUSION: The maintenance of host-specific signals in spatially and temporally separated C. jejuni populations suggests the existence of strong purifying selection for this bacterium in European Blackbirds.

  • 6.
    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.

  • 7.
    Griekspoor, Petra
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Olsen, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Waldenström, Jonas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Campylobacter jejuni in penguins, Antarctica2009In: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 15, no 5, p. 847-849Article in journal (Refereed)
  • 8.
    Griekspoor, Petra
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Olsson Engvall, Eva
    National Veterinary Institute.
    Åkerlind, Britt
    Linköping University.
    Olsen, Björn
    Uppsala University.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Genetic diversity and host associations in Campylobacter jejuni from human cases and broilers in 2000 and 20082015In: Veterinary Microbiology, ISSN 0378-1135, E-ISSN 1873-2542, Vol. 178, no 1-2, p. 94-98Article in journal (Refereed)
    Abstract [en]

    Campylobacter jejuni is an important food-borne pathogen, with a global distribution. It can colonize numerous host species, including both domestic and wild animals, but is particularly associated with birds (poultry and wild birds). For human campylobacteriosis, poultry products are deemed the most significant risk factor for acquiring infection. We conducted a genotyping and host attribution study of a large representative collection of C. jejuni isolated from humans and broilers in Sweden in the years 2000 and 2008. In total 673 broiler and human isolates from 10 different abattoirs and 6 different hospitals were genotyped with multilocus sequence typing. Source attribution analyses confirmed the strong linkage between broiler C. jejuni and domestic human cases, but also indicated a significant association to genotypes more commonly found in wild birds. Genotype distributions did not change dramatically between the two study years, suggesting a stable population of infecting bacteria.

  • 9. Keller, Judith I
    et al.
    Shriver, W Gregory
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Griekspoor, Petra
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olsen, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Prevalence of Campylobacter in wild birds of the mid-Atlantic region, USA.2011In: Journal of Wildlife Diseases, ISSN 0090-3558, E-ISSN 1943-3700, Vol. 47, no 3, p. 750-754Article in journal (Refereed)
    Abstract [en]

    We evaluated the occurrence of three Campylobacter species--C. jejuni, C. coli, and C. lari--from 333 wild bird fecal samples collected at Tri-State Bird Rescue and Research in Newark, Delaware, in 2008. Using multiplex polymerase chain reaction, we detected C. jejuni from six avian families with an overall prevalence rate of 7.2%. We did not detect any other Campylobacter species. Campylobacter jejuni prevalence ranged widely between different avian families with crows (Corvidae) and gulls (Laridae) having the highest prevalence rates (23% and 25%, respectively).

  • 10.
    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.

  • 11.
    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.

  • 12.
    Waldenström, Jonas
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Griekspoor, Petra
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Ecology and Host Association in Campylobacter in Wild Birds2014In: Campylobacter Ecology and Evolution / [ed] Sheppard, S., Norfolk: Caister Academic Press, 2014, p. 265-284Chapter in book (Refereed)
    Abstract [en]

    The following review aims to summarize the present knowledge on Campylobacter jejuni and other Campylobacter-species in wild birds. The question of whether campylobacters present in wildlife, especially those found in wild birds, play a role in the epidemiology of human campylobacteriosis has been around for more than 30 years (Kapperud and Rosef, 1983; Smibert, 1969). This review will summarize what is currently known and point to the gaps in understanding of these organisms and their interplay with hosts and the environment. Here the focus will mainly be on C. jejuni, as this species has received most attention, but data for Campylobacter coli and Campylobacter lari will also be discussed.

1 - 12 of 12
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • 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