A retrospective study on the isolated strains of Salmonella in poultry

Poultry represents a significant global reservoir of Salmonella spp. Poultry salmonellosis results in significant economic losses, and some serovars also have zoonotic potential. Some poultry can be infected with Salmonella species without showing clinical signs of the disease, but it is a significant source of the spread of the infection. Clinical symptoms range from digestive problems (white diarrhea, malabsorption) to bacteremia and death. This study aimed to retrospectively show the presence of bacteria Salmonella enterica subspecies enterica of various serovars in poultry in the Belgrade epizootiological area in a period of six years (2014-2019). A total of 4580 samples were examined, including incubated eggs, dead chickens, broiler feces, and laying hens with 207 positive samples. Salmonella was isolated by standard microbiological methods followed by serological typing. In the examined period, the prevalence of poultry salmonella was 4.52%. The highest number of examined samples was recorded in 2017 (879) and positive in 2018 (65), while the lowest prevalence was recorded during the year 2016 with 7 positive samples. Of all isolated and serotyped Salmonella , the most commonly isolated serovar was S. Enteritidis (65.28%), followed by S. Infantis (21.30%), S. Mbandaka (6.02%), S. Senftenberg (3.24%), S. Typhimurium (1.85%), S. Agona (0.93%), S. Taksony (0.93%), and the least common is S. Tshiongwe (0.46%). The first report of serovars: S. Agona, S. Taksony and S. Tshiongwe have been during 2018. The highest number of positive specimens was found in laying hens faces (116 of 921 tested), broiler faces (73 of 1147), chickens carcasses (12 of 1443), and incubated eggs (6 of 1069). Complete eradication of Salmonella from production is a challenging goal because of a heterogeneous serovars pool and various sources of infection. Prevention is the best tool for controlling Salmonella: hygiene, biosecurity, and where applicable -vaccination. It is a great responsibility of the poultry farmers to apply the existing standards and to improve the new ones.