From wild birds to humans through surface water a dive into C. jejuni ecology in Luxembourg
Abstract T11
Presenter: Louise Hock (Luxembourg Institute of Sciences and Technology)
Luxembourg presents one of the highest incidences of Campylobacter infections in the European Union (EU), reaching an incidence rate of 103.8 cases per 100,000 population in 2018. Campylobacter jejuni was confirmed in 83.1% of campylobacteriosis cases (EFSA and ECDC, 2019). Most cases were attributed to poultry (61.2 %) and ruminants (33.3%) sources but all warm-blooded animals are considered as asymptomatic and amplifying hosts for Campylobacter. The transmission of this pathogen to humans may occur through multiple ways, including food, water, environment, animals and person-to-person contact (Mossong et al., 2016).
The CampylOmic project aims i.a. to assess the Campylobacter prevalence in wild birds to enhance our understanding of its transmission pathways from the primary host towards humans. More than 300 wild bird faeces were collected between 2019 and 2021 from 34 species including resident, waterfowl and migratory birds. Campylobacter strains were isolated after passive-filtration method based on the migration ability of small and motile Campylobacter through 0.65 m pores of filtration membranes places upside-up on selective solid media. The whole-genome sequencing (Illumina DNA Prep) of isolated Campylobacter allowed to assign their sequence and complex types. Through a comparison with a human isolates collection, the prevalence of human recurring genotypes in wild birds is being assessed. In parallel, 76 surface waters in Luxembourg were also sampled to investigate their contamination by wild birds strains. C. jejuni is present in 19% and 13% of wild birds and surface waters, respectively. The most contaminated studied bird species by C. jejuni are Western jackdaws or Corvus monedula (75%, n=12) and Carrion crows or Corvus corone (71%, n=24), True thrushes or Turdus (55%, n=20), Magpies or Pica Pica (54%, n=13), Starlings or Sturnus (33%, n=3) and Falcons or Falco (24%, n=17). The 100 C. jejuni strains from wilds birds were assigned to 40 STs. The six most frequent STs, ST-45, ST-383, ST-448, ST-19, ST-677 and ST-11, accounted for 41% of bird isolates. The nine C. jejuni isolates from surface water were assigned to six STs: ST-9897, ST-704, ST-991, ST-4279, ST-538 and ST-683. Only the ST-4279 is present in wild birds (Corvus corone) and surface water. One isolate coming from a bird (Corvus corone) is a human recurring genotype (ST-48) observed between 2016 and 2018 in patients from Luxembourg. One other isolate corresponds to a sporadic human case (ST-475) and has been detected in a black Swift (Apus Apus). By completing the picture of Campylobacter population structure in space and time based on a One-Health approach, new explanations of genotypes persistence in human infections will be assessed. This gain in transmission pathways comprehension will be helpful to guide and reduce the public health impact of Campylobacter.
About the presenter
After studying Bioscience Engineering oriented on Science, Technology and Food quality in Belgium (UCLouvain), Louise realised a PhD thesis in food and environmental microbiology with the aim to explore the biocontrol of Bacillus cereus by bacteriophages for improving food safety. Afterwards and since three years, she is working as a research associate in environmental microbiology at the Luxembourg Institute of Science and Technology (LIST) on several projects linked to the One-Health approach improving knowledge on pathogenic bacteria and finding new weapons in the war against antibiotic resistance.
Presenting in Speaking session 1 - Host adaptation