InvA gene sequencing of salmonella typhimurium isolated from Egyptian poultry

Abstract

Background and Objective: Salmonella typhimurium is one of the most important zoonotic pathogenic microorganisms affecting man and animals, the traditional phenotypical identification of Salmonella involving microbiological enrichment and subsequent identification, usually cannot indicate the genetic determinants of the isolates causing disease. Therefore, the aim of this study was to sequence the invA gene of local isolate which is a very important tool for periodical evaluation of mutagenicity compared with the published sequences on GenBank. Materials and Methods: The collected poultry samples were screened for Salmonella typhimurium using different biochemical and serological studies. The positive isolates were examined by PCR for detection of invA gene at specific molecular size (2058 bp) using specific sensitized primers (forward and reverse). Sequencing of the invA gene was performed and compared with the published sequences on GenBank. Results: The homology percentage of nucleotide sequence (99.2-99.4%) and amino acid sequence (99.6-99.9%) showed high similarity between the local isolates and the other published sequences on GenBank. Conclusion: Sequence analysis of the Egyptian S. typhimurium revealed that it is mandatory to monitor any changes in the genomic structure, similarity and dissimilarity with other strains in the region and all over the world.