Prevalence of Different Salmonella enterica Subspecies and Serotypes in Wild Carnivores in Emilia-Romagna Region, Italy

Simple Summary Salmonellae are enteric bacteria capable of infecting humans and both domestic and wild animals. Even if salmonellosis in humans is generally transmitted through food, the role of wildlife in the ecology of this bacteria is of increasing interest because of their potential role as reservoirs. In Italy, and in particular in the Apennines area, the interactions between wildlife and humans, pets and livestock are rising due to a growing wildlife population and this poses the problem of accidental Salmonella infections. The aim of this study was to investigate the presence of Salmonella subspecies and serotypes in wild carnivores (namely red fox, European badger and wolf) from the Emilia-Romagna Region between 2016 and 2022. Samples of the large intestine were cultured, and both serogroup and serotype identification were performed. A total of 67 strains were isolated, belonging to S. enterica subsp. enterica, S. salamae, S. diarizonae and S. houtenae. The most frequently isolated serotypes were S. veneziana and S. typhimurium. These findings highlight a prevalence of Salmonella spp. in line with other studies, showing once again the value of monitoring different possible sources of Salmonella infection. Salmonella is a pathogen of considerable health concern, given its zoonotic potential, and, in Italy, is the most frequently reported causative agent for foodborne outbreaks. Wild animals and in particular wild carnivores may be carriers of different Salmonella enterica subspecies and serotypes. Given their potential role as reservoirs, surveillance activities are necessary. This study aims to investigate the presence of different Salmonella subspecies and serotypes in wild carnivores in the Emilia-Romagna Region. A total of 718 fox (Vulpes vulpes), 182 badger (Meles meles) and 27 wolf (Canis lupus) carcasses, submitted between 2016-2022, were included for the present work. Gender and age data were collected along with geographical coordinates of carcass' discovery site. Contents of the large intestine were sampled and cultured according to ISO 6579-1 and both serogroup and serotype identification were performed according to ISO/TR 6579-3:2014. Salmonella was retrieved from 42 foxes (6%), 21 badgers (12%) and 3 wolves (12%), respectively. Isolated Salmonella enterica strains belonged to 4 different subspecies and 25 different serotypes. S. veneziana and S. typhimurium were the most frequent serotypes found (11/67 and 10/67, respectively). In conclusion, zoonotic serotypes were found in all these species of wildlife, thus confirming their potential role in the ecology of Salmonella spp.

Automated summary

This study investigated the presence of Salmonella subspecies and serotypes in wild carnivores (red fox, European badger, and wolf) in the Emilia-Romagna Region, Italy. The results showed a prevalence of Salmonella spp. in these wildlife species, with S. veneziana and S. typhimurium being the most common serotypes.