Evaluation and Sequencing of 16S rRNA Gene for Molecular Identification of Prevalent Salmonella Strains Isolated from Food and Water

Abstract

Salmonella is a leading cause of intestinal illnesses globally and is also responsible for severe systemic diseases such as typhoid and paratyphoid fevers, often transmitted through contaminated food. Understanding the prevalence and genetic diversity of Salmonella is essential to addressing its public health impact. This study investigates the prevalence and genetic diversity of Salmonella strains in food and water samples from Karachi, with a focus on the 16S rRNA gene for phylogenetic analysis and the InvA gene as a virulence marker. A total of 110 food and water samples were analyzed using microbiological assays, PCR, gene sequencing, and phylogenetic grouping. The 16S rRNA gene, known for its evolutionary stability, was employed to identify bacterial species and trace phylogenetic relationships. The InvA gene, a key virulence factor, was detected to assess pathogenic potential. Gene sequencing and phylogenetic analysis were conducted using MEGA-X software to construct a Maximum Likelihood phylogenetic tree incorporating newly sequenced and reference strains. The study identified Salmonella isolates and revealed their evolutionary relationships and geographic origins. The phylogenetic analysis demonstrated genetic diversity among the isolates, highlighting their potential public health implications. The findings provide valuable insights into the genetic diversity of Salmonella in food and water samples from Karachi. These results underline the importance of molecular surveillance in understanding Salmonella evolution and controlling its public health impact.