Skip to main content
ARS Home » Research » Publications at this Location » Publication #164633
Title: COLONIZATION OF REPRODUCTIVE ORGANS AND INTERNAL CONTAMINATION OF EGGS AFTER EXPERIMENTAL INFECTION OF LAYING HENS WITH SALMONELLA HEIDELBERG AND SALMONELLA ENTERITIDIS

Author
item Gast, Richard
item Guard, Jean
item Holt, Peter

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2004
Publication Date: 12/1/2004
Citation: Gast, R.K., Bouldin, J.G., Holt, P.S. 2004. Colonization of reproductive organs and internal contamination of eggs after experimental infection of laying hens with salmonella heidelberg and salmonella enteritidis. Avian Diseases. 48:863-869

Interpretive Summary: Since the 1980's, public health authorities have been reporting that eggs containing Salmonella enteritidis in their edible liquid contents are transmitting disease to humans. Because of this concern, considerable resources have been invested in programs to detect and control S. enteritidis infections in commercial egg-laying flocks. Recently, the Centers for Disease Control and Prevention also reported a significant association between eggs or egg-containing foods and S. heidelberg infections in humans. Because prior research has demonstrated that S. enteritidis is deposited inside eggs after colonizing the reproductive organs (ovaries and oviducts) of laying hens, the present study sought to determine whether several S. heidelberg isolates (obtained from egg-associated human disease outbreaks) were also able to colonize reproductive tissues and be deposited inside eggs laid by experimentally infected hens. Groups of laying hens were orally infected with large doses of four S. heidelberg strains and an S. enteritidis strain known to be capable of causing egg contamination. Like the S. enteritidis strain, the four S. heidelberg strains colonized the intestinal tracts and invaded to reach the livers, spleens, ovaries, and oviducts of inoculated hens. All four S. heidelberg strains were recovered from the interior liquid contents of eggs laid by infected hens, although less often than the S. enteritidis strain. This demonstrates that some S. heidelberg strains are able to colonize the reproductive tracts of laying hens and cause egg contamination in a manner similar to S. enteritidis.

Technical Abstract: Internal contamination of eggs laid by hens infected with Salmonella enteritidis has been a prominent international public health issues since the mid 1980's. Considerable resources have been committed to detecting and controlling S. enteritidis infections in commercial laying flocks. Recently, the Centers for Disease Control and Prevention also reported a significant association between eggs or egg-containing foods and S. heidelberg infections in humans. The present study sought to determine whether several S. heidelberg isolates obtained from egg-associated human disease outbreaks were able to colonize reproductive tissues and be deposited inside eggs laid by experimentally infected hens in a manner similar to the previously documented behavior of S. enteritidis. In two trials, groups of laying hens were orally inoculated with large doses of four S. heidelberg strains and an S. enteritidis strain that consistently caused egg contamination in prior studies. All five Salmonella strains (of both serotypes) colonized the intestinal tracts and invaded to reach the livers, spleens, ovaries, and oviducts of inoculated hens, with no significant differences observed between the strains for any of these parameters. All four S. heidelberg strains were recovered from the interior liquid contents of eggs laid by infected hens, although at lower frequencies (between 1.1% and 4.5%) than the S. enteritidis strain (7.0%).