Molecular investigation on Listeria monocytogenes and Salmonella enteritidis in table eggs and diarrheic patients

Listeria monocytogenes (L. monocytogenes) is a widely distributed zoonotic foodborne pathogen capable of surviving under harsh environmental conditions, including low pH and high salt concentrations. Eggs and egg products represent one of the most common sources of human salmonellosis, primarily caused by Salmonella enterica serovar Enteritidis (S. enteritidis). Accordingly, the present study was conducted to perform a molecular investigation of L. monocytogenes and S. enteritidis in table eggs and stool samples obtained from diarrheic patients. A total of 58 pooled samples of fresh hen's eggs, along with 34 stool samples, were collected and subjected to DNA extraction followed by polymerase chain reaction (PCR) analysis. The results revealed the presence of L. monocytogenes and S. enteritidis DNA in 55.2% and 50% of the examined egg samples, respectively. A higher prevalence of L. monocytogenes was detected on eggshells compared to egg contents. Variations in infection rates were observed based on gender and age; L. monocytogenes infections were more frequently identified in males and younger individuals, whereas S. enteritidis infections were more common among females and older children. Gastrointestinal symptoms were associated with both infections, with abdominal pain being particularly prevalent in patients infected with S. enteritidis. In conclusion, the findings of this study highlight the potential zoonotic risk posed to consumers and underscore the urgent need for implementing effective control programs in laying hen farms.