Infectious Diseases 2021

Infectious Diseases 2021

Salmonella Infantis in Dutch broiler flocks - Study

Veterinary Microbiology 2021 Vol 258 18 October, 2021

Salmonella Infantis is a poultry-adapted Salmonella enterica serovar that is increasingly reported in broilers and is also regularly identified among human salmonellosis cases.
Since 2014, S. Infantis has been the most commonly isolated serovar in broilers in the Netherlands, accounting for 78% of all Salmonella isolates from broilers reported in 2018. Also Europe-wide, S. Infantis is currently the most common serovar in broilers (46–57%) and broiler meat (37–51%),and its prevalence has increased in breeding flocks as well.
An emerging S. Infantis mega-plasmid (pESI), carrying fitness, virulence and antimicrobial resistance genes, is also increasingly found. Dutch researchers investigated the prevalence, genetic characteristics and risk factors for (pESI-carrying) S. Infantis in broilers. The rapid spread of S. Infantis in broilers has been related to the occurrence of the pESI mega-plasmid carrying genes associated with fitness, virulence and antimicrobial resistance.
An increased risk for S. Infantis colonization was found for flocks in which salinomycin was used, as well as flocks where thinning was applied or where litter quality was poor. This study shows that a heterogenous (pESI-carrying) S. Infantis population has successfully established itself in broiler flocks in the Netherlands, with a prevalence of around 5% and some indications of potential vertical transmission.