Molecular epidemiology and virulence properties of Salmonella Enteritidis isolated from an outbreak of gastroenteritis in turkeys

Abstract

Strains (28) of Salmonella Enteritidis were isolated during an outbreak of acute gastroenteritis in adult turkeys in Mizoram, India. Morbidity and case fatality rate were 25.10 and 34.38%, respectively. Phenotypic characterization by morphological studies, antibiotic sensitivity assay, Congo Red binding assay and salt aggregation assay could not ascertain the source of the infection. All the 28 strains yielded amplicons of ~1103 bp, ~700 bp and ~617 bp specific for sefC, pefA and stn genes, respectively, by a multiplex PCR assay. Presence of all the virulence genes supported the severity of the disease in adult birds. Enterobacterial repetitive intergenic consensus (ERIC) -PCR, randomly amplified polymorphic DNA (RAPD) -PCR and repetitive extragenic palindromic (REP) -PCR assays recorded the genotypic similarity of all the 28 isolates as well as 2 isolates of S. Enteritidis obtained from feed. The current investigation revealed the involvement of contaminated feed for the outbreak of a severe gastroenteritis in turkeys. As Salmonella Enteritidis is one of the most common food-borne zoonotic agents of human beings, the presence of such pathogenic organism in food animal poses a serious threat to public health. The results also indicated that molecular techniques for detection and characterization of Salmonella Enteritidis were rapid in comparison with conventional methods, for epidemiological investigation of salmonellosis outbreak.