Molecular detection of pathogenic serovar Salmonella enteritidis by LAMP method using a specific marker screened by comparative genomic methods

Abstract

Background and Aim: Salmonella enteritidis is one of the most common causes of gastroenteritis, and in acute cases may lead to septicemia and even death. In this study, genetic markers of serovar were screened by comparative genomic methods, and the most specific marker was targeted to identify this pathetic serover by LAMP method. Materials and Methods: This study was done in 2016. To find genetic markers of S. enteritidis, 50 complete genomes of S. enteritidis and other genera belonging to Enterobacteriacea family were compared by different comparative genomic methods. The specific marker was selected and targeted by the LAMP method using six special primers to demonstrate the feasibility of comparative genomic methods for screening specific genetic markers (The bacterial strains used in this study were collected from hospitals in the Southast of Iran). The efficiency of LAMP assay for the identification of this bacterium was also evaluated in artificially contaminated chicken meat samples. Results: lygC gene was selected as the most specific marker for detecting S. enteritidis strains. LAMP assay results showed that the selected gene is specific for detecting S. enteritidis isolates. The assay sensitivity was determined to be 10 CFU/reaction for pure bacterial culture, 103 CFU/mL for contaminated chicken meat samples without pre-enrichment, and 10 CFU/mL after a 4-h pre-enrichment. Conclusions: The present study demonstrates that comparative genomic methods are efficient tools for the identification of specific genetic markers. Also, the present LAMP method could be used as a powerful, accurate and inexpensive tool for detecting S. enteritidis in food quality and clinical laboratories.

Keywords

• Salmonella enteritidis
• Specific Marker
• Comparative genomic
• LAMP assay