Immunoglobulin Response to Salmonella Enteritidis Outer Membrane Proteins

Abstract

There has been a steady increase in the incidence of Salmonellosis in humans over the past decade in part due to consumption of eggs and poultry products contaminated with Salmonella enteritidis (SE). Identifying the SE infectious status of flocks is critical for maintaining safety in food production and the economic welfare of poultry producers. Traditionally, bacterial cultures of fecal drag swabs, organs and egg samples are used to monitor the status of flocks for SE. Despite the high sensitivity and specificity of bacterial culture techniques, the extremely low incidence of SE shedding in eggs (<0.03%) may preclude detection by culture. Although published reports have indicated that environmental cultures may have predictive value for an older flock’s potential to produce contaminated eggs, results of environmental cultures may hold little predictive value for young flocks and instead result in the diversion of large numbers of eggs when the risk of SE positive eggs is still very low (Schlosser et al., 1995). Evaluation of the immune status of birds by the enzyme linked immunosorbent assay (ELISA) has the potential to predict SE infectious status with a sensitivity comparable to the low incidence of SE shedding in eggs. This research focuses on the development of a diagnostic ELISA used for detecting anti-Salmonella enteritidis outer membrane protein (OMP) antibodies in egg yolk samples that may reliably predict the likelihood of SE shedding in eggs. Results of egg yolk and serum OMP ELISAs are correlated with a commercial ELISA kit and culture data from egg and tissue samples from the same birds.