Distribution of Salmonella spp. Serotypes Isolated from Poultry in Abruzzo and Molise Regions (Italy) during a 6-Year Period

Abstract

Human salmonellosis incidence is increasing in the European Union (EU). Salmonellaenterica subsp. enterica serovar Enteriditis, Salmonellaenterica subsp. enterica serovar Typhimurium (including its monophasic variant) and Salmonellaenterica subsp. enterica serovar Infantis represent targets in control programs due to their frequent association with human cases. This study aimed to detect the most prevalent serotypes circulating in Abruzzo and Molise Regions between 2015 and 2020 in the framework of the Italian National Control Program for Salmonellosis in Poultry (PNCS)]. A total of 332 flocks of Abruzzo and Molise Regions were sampled by veterinary services in the period considered, and 2791 samples were taken. Samples were represented by faeces and dust from different categories of poultry flocks: laying hens (n = 284), broilers (n = 998), breeding chickens (n = 1353) and breeding or fattening turkeys (n = 156). Breeding and fattening turkeys had the highest rate of samples positive for Salmonella spp. (52.6%; C.I. 44.8%–60.3%). Faeces recovered through boot socks represented the greatest number of positive samples (18.2%). Salmonellaenterica subsp. enterica serovar Infantis was the prevalent serotype in breeding and fattening turkeys (32.7%; C.I. 25.8%–40.4%) and in broiler flocks (16.5%; C.I. 14.4%–19.0%). Salmonellaenterica subsp. enterica serovar Typhimurium was detected at low levels in laying hens (0.7%; C.I. 0.2%–2.5%) followed by breeding and fattening turkeys (0.6%; C.I. 0.2%–2.5%). Salmonellaenterica subsp. enterica serovar Enteriditis was also detected at low levels in laying hens (2.5%; C.I. 1.2%–5.0%). These findings highlight the role of broilers and breeding/fattening turkeys as reservoirs of Salmonella spp. and, as a consequence, in the diffusion of dangerous serotypes as Salmonellaenterica subsp. enterica serovar Infantis. This information could help veterinary services to analyze local trends and to take decisions not only based on indications from national control programs, but also based on real situations at farms in their own competence areas.