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Updated: Jun 17, 2026
Discovery of New Intracellular Pathogens by Amoebal Coculture and Amoebal Enrichment Approaches
Published on: October 27, 2013
Amoebae and algae can prolong the survival of Campylobacter species in co-culture
Diana Axelsson-Olsson1, Jenny Olofsson, Lovisa Svensson
1Section for Zoonotic Ecology and Epidemiology, University of Kalmar, SE-391 82 Kalmar, Sweden. diana.axelsson-olsson@lnu.se
Abstract:
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.
Insights
Free-living amoebae and other unicellular eukaryotes can host pathogenic bacteria like Campylobacter. Certain amoebae and golden algae promote Campylobacter survival and replication, suggesting a role in disease spread.
Area of Science:
- Environmental microbiology
- Microbial ecology
- Pathogen survival
Background:
- Free-living amoebae act as environmental hosts for pathogenic bacteria, indirectly influencing disease epidemiology.
- Intracellular survival of bacteria within amoebae is known, but its extent and epidemiological implications are underestimated.
Purpose of the Study:
- To evaluate eight different unicellular eukaryotes as potential environmental hosts for Campylobacter species.
- To assess the survival and replication of key Campylobacter species (C. jejuni, C. coli, C. lari, C. hyointestinalis) in co-cultures with these eukaryotes.
Main Methods:
- Co-culture experiments were performed using eight eukaryotic species: four amoebozoas (Acanthamoeba spp., Hartmanella vermiformis), Tetrahymena pyriformis, Dinobryon sertularia, Euglena gracilis, and Naegleria americana.
- Bacterial survival and replication were monitored over time in co-cultures compared to standard growth media.
Main Results:
- Campylobacter species demonstrated prolonged survival in co-cultures compared to growth media alone.
- The golden algae Dinobryon sertularia significantly enhanced Campylobacter survival.
- Three Acanthamoeba species promoted both prolonged survival and replication of Campylobacter spp.
Conclusions:
- Unicellular eukaryotes, particularly Acanthamoeba species and D. sertularia, can serve as environmental hosts for Campylobacter.
- The widespread presence of these hosts in aquatic environments suggests a significant role in the epidemiology and dissemination of campylobacteriosis.
