Current advances in molecular subtyping using multilocus variable number of tandem repeat analysis of Salmonella Enteritidis and Salmonella Typhimurium in Egyptian chickens

• Published in: Veterinary World 2020-10, Vol.13 (10), p.2252-2259
• Main Authors: Hassan, Wafaa M M, Tawab, Ashraf A Abd El, El-Shannat, Sara M
• Format: Article
• Language: English
• Subjects: Abattoirs; Analysis; Deoxyribonucleic acid; Development and progression; Disease transmission; DNA; Epidemiology; Evolution; Genetic diversity; Genotypes; Lipopolysaccharides; multilocus variable number of tandem repeat analysis; Polymerase chain reaction; Salmonella; Salmonella Enteritidis; Salmonella Typhimurium; Serotyping
• ISSN: 0972-8988; 2231-0916
• DOI: 10.14202/vetworld.2020.2252-2259

This study aimed to characterize the genetic diversity, evolutionary level, and prevalence of genotypes of common isolates of ( Enteritidis and Typhimurium). Using one of the most advanced molecular recognition techniques, multilocus variable number of tandem repeat analysis (MLVA), we characterized the genotype and prevalence of . Enteritidis and . Typhimurium. One hundred and twenty-five internal organ samples were collected from the major chicken slaughterhouses in Egypt, and species were isolated. PCR was utilized to amplify the and genes to identify . Enteritidis and . Typhimurium DNA, respectively, from isolates. MLVA was applied on nine samples of . Enteritidis DNA and three samples of . Typhimurium DNA. Six variable number tandem repeat (VNTR) loci (Sal02, Sal04, Sal06, Sal10, Sal20, and Sal23) were amplified. Of the examined samples (n=125), a total of 12 isolates (9.6%) were either identified as Enteritidis or Typhimurium. PCR-mediated amplification of and revealed that 75% (n=9) of the 12 isolates were . Enteritidis and 25% (n=3) were . Typhimurium. The six loci amplified through MLVA had allelic diversity. The most discriminatory heterogenic locus for . Enteritidis was Sal20. Sal04 and Sal23 were the most discriminatory heterogenic loci for . Typhimurium. VNTR allelic profile analysis revealed nine unique genotypes for . Enteritidis and three for . Typhimurium. This study was the first to use MLVA analysis to identify . Enteritidis and . Typhimurium strains isolated from chickens in Egypt. The molecular typing data reported herein allowed us to characterize the genotypes of . Enteritidis and . Typhimurium that are most prevalent in Egyptian chickens. Moreover, this epidemiological information provides valuable insight on how to prevent disease transmission. Moreover, our methods provide an alternative to traditional serotyping techniques that may produce inaccurate strain identifications for organisms with rough lipopolysaccharide structures.