Detection and characterization of Salmonella spp. in wildlife in France
Résumé
In 2019, 87 923 confirmed cases of salmonellosis were reported in Europe. It’s one of the leading causes of foodborne enteric illness in humans. The main cause of human infection is the consumption of products derived from poultry, cattle and swine productions. Salmonella colonizes the intestinal tract of many species, including mammals, birds, cold-blooded animals, and Salmonella transmission between animals can occur through the environment and close contact with animals. In this context, wildlife plays an important role in the maintenance and transmission of this pathogen. The purpose of this study, conducted within the European EJP OH project “Discover”, was to investigate the carriage of Salmonella spp. in wildlife in France.
In collaboration with the French Biodiversity Agency (OFB) and French accredited laboratories, a total of 162 samples collected from wild animals (deer, wild boar, hare, turtledove, swan, thrush…) during a 10-month period (between 2019 and 2020) and covering different areas of France, were analyzed. Nine samples tested positive for Salmonella spp. allowing the estimation of a prevalence of 5.6 % within the collected samples. All isolated strains sent to the French National Reference Laboratory (NRL) were genotyped using whole genome sequencing (WGS). Although the prevalence is low, a diversity of Salmonella serotypes was observed: Salmonella enterica serotype Enteritidis, Typhimurium, Napoli and Salmonella arizonae (48 : Z4, Z23 : -). WGS data allowed to predict in silico the serotypes, investigate genomic features such as antimicrobial resistance and virulence genes, and build phylogenetic clusters using core genome multilocus sequence typing (cgMLST). This investigation allowed to collect first data about Salmonella in wildlife in France. It also provided some insight about the epidemiology of Salmonella population circulating in wildlife, including genotypes, antimicrobial resistance and virulence genes.