Research On The Molecular Epidemiology Of Salmonella In Yangzhou Scale Geese Breeding Farm

Salmonella is one of the significant pathogens causing food-borne illness and widely distributed in word.It has long caused serious damage to human health and livestock and poultry husbandry,the goose breeding industry is especially serious impact in recent years.This study investigated Salmonella contamination and serotype distribution in the hatching,breeding,and slaughter stages of a goose farm in Yangzhou,and investigated the pathogenicity of dominant serotypes in goose and goose embryos perform molecular typing in these isolates,in order to understand the relationship between strains from different link sources in goose field production chain,find out key link in pollution.This study provides important data support for salmonella elimination and poultry safety in the poultry industry.In this study,the incubation,cultivation and slaughtering of this goose farm were sample collection.A total of 903 samples were collected and 329 Salmonella isolates were isolated.The total positive rate was 36.4%.The isolation rates of Salmonella in the hatchery samples,aquaculture samples and slaughtered samples were 51.8%,17.6%and 43.8%,respectively.The Salmonella contamination in the dead embryos,water and viscera is severe.In addition,the isolation rate of Salmonella was influenced by the seasonal change.Serological results showed that Salmonella Potsdam is the most predominant serotype in the incubation process.Salmonella Typhimurium is the most predominant serotype in both farming and slaughtering.Other serovars such as S.Certbus,S.Newport,S.Cerro,were also widely spread.According to the distribution of Salmonella in the goose farm,the environment in the hatchery is a key factor in the pollution of the entire industry chain.In this study,165 strains of Salmonella were selected for drug resistance testing.The results showed that the resistance was not obvious.In addition,the study selected the predominant serotypes Salmonella Potsdam infected the goose and goose embryos and observed the clinical manifestations and pathological changes.It was found that there was only a slight pathological change of the goose after infection,but it had a high mortality rate after infected goose embryos,which seriously affected the hatching of goose embryos.82 strains of Salmonella were selected for Multi-site sequence typing(MLST).49 strains of Slmonella Potsdam were selected and 12 strains of Salmonella Typhimurium were used for PFGE typing.MLST indicated that ST2039 and ST99 ST-type Salmonella strains were the most common ST in different sources.Pulsed-field gel electrophoresis(PFGE)typing showed that there were 6 and 5 PFGE types in 37 strains of Salmonella Potsdam and 12 strains of Salmonella Typhimurium.This indicates that the PFGE type of Salmonella Potsdami from the same production link at different time sources is almost identical,and these Salmonella may be the autochthonous flora in the incubation stage of the goose farm,causing continuous pollution to the hatchery.The Salmonella Typhimurium and PFGE bands in different production stages of the goose farm also have great consistency,which shows that Salmonella Typhimurium has horizontal transmission in the production chain of the goose farm.