Population genetics and characterization of Campylobacter jejuni isolates from western jackdaws and game birds in Finland

Sara Kovanen, Mirko Rossi, Mari Pohja-Mykrä, Timo Nieminen, Mirja Raunio-Saarnisto, Mikaela Sauvala, Maria Fredriksson-Ahomaa, Marja-Liisa Hänninen, Rauni Inari Kivistö

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Poultry are considered a major reservoir and source of human campylobacteriosis, but the roles of environmental reservoirs, including wild birds, have not been assessed in depth. In this study, we isolated and characterized Campylobacter jejuni from western jackdaws (n = 91, 43%), mallard ducks (n = 82, 76%), and pheasants (n = 9, 9%). Most of the western jackdaw and mallard duck C. jejuni isolates represented multilocus sequence typing (MLST) sequence types (STs) that diverged from those previously isolated from human patients and various animal species, whereas all pheasant isolates represented ST-19, a common ST among human patients and other hosts worldwide. Whole-genome MLST revealed that mallard duck ST-2314 and pheasant ST-19 isolates represented bacterial clones that were genetically highly similar to human isolates detected previously. Further analyses revealed that in addition to a divergent ClonalFrame genealogy, certain genomic characteristics of the western jackdaw C. jejuni isolates, e.g., a novel cdtABC gene cluster and the type VI secretion system (T6SS), may affect their host specificity and virulence. Game birds may thus pose a risk for acquiring campylobacteriosis; therefore, hygienic measures during slaughter and meat handling warrant special attention.

IMPORTANCE The roles of environmental reservoirs, including wild birds, in the molecular epidemiology of Campylobacter jejuni have not been assessed in depth. Our results showed that game birds may pose a risk for acquiring campylobacteriosis, because they had C. jejuni genomotypes highly similar to human isolates detected previously. Therefore, hygienic measures during slaughter and meat handling warrant special attention. On the contrary, a unique phylogeny was revealed for the western jackdaw isolates, and certain genomic characteristics identified among these isolates are hypothesized to affect their host specificity and virulence. Comparative genomics within sequence types (STs), using whole-genome multilocus sequence typing (wgMLST), and phylogenomics are efficient methods to analyze the genomic relationships of C. jejuni isolates.
Original languageEnglish
Article numberUNSP e02365-18
JournalApplied and Environmental Microbiology
Volume85
Issue number4
Number of pages16
ISSN0099-2240
DOIs
Publication statusPublished - Feb 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1183 Plant biology, microbiology, virology
  • Campylobacter jejuni
  • antimicrobial resistance
  • comparative genomics
  • cytolethal distending toxin
  • mallard duck
  • pheasant
  • public health
  • western jackdaw
  • whole-genome sequencing
  • 416 Food Science
  • 3142 Public health care science, environmental and occupational health
  • Campylobacter jejuni
  • antimicrobial resistance
  • comparative genomics
  • cytolethal distending toxin
  • mallard duck
  • pheasant
  • public health
  • western jackdaw
  • whole-genome sequencing
  • CYTOLETHAL DISTENDING TOXIN
  • MULTILOCUS SEQUENCE TYPES
  • ANTIMICROBIAL RESISTANCE
  • ANNOTATION
  • VIRULENCE
  • HOST
  • IDENTIFICATION
  • COLONIZATION
  • TRANSMISSION
  • INFECTIONS

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