Multiplex PCR-based detection of Salmonella typhimurium and Salmonella enteritidis in Specific Pathogen Free (SPF) and Commercial Eggs

Abstract

Salmonella serovars are one of the major bacterial causes of food borne diseases. Eggs are commonly identified as food sources responsible for salmonellosis outbreaks. This study aimed to isolate Salmonella Typhimurium and Salmonella Enteritidis from 1750 hens' eggs, and use of multiplex polymerase chain reaction (Multiplex PCR) in the identification of different Salmonella serovars from eggs. The incidence of salmonellae among the Balady eggs yolk was 1.3%, while the incidence was 1.2% among white and brown eggs samples (each). S. Typhimurium and S. Enteritidis were identified (0.6 and 0.5% respectively). The isolates were confirmed using fliC, sefA genes and gene specific for genus Salmonella. All albumen samples negative for isolation of isolation of salmonellae by culture method were retested by PCR. From the retested albumen samples 3%, 8.4% and 6% collected from Balady, white and brown eggs respectively were positive for Salmonella serovars using Multiplex PCR. No salmonellae could be detected from specific pathogen free (SPF) eggs using both PCR and conventional methods.