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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Biosciences & Biotechnology Laboratory » Research » Publications at this Location » Publication #339218

Title: Assessing tissue colonization and egg contamination by Salmonella Oranienburg in laying hens

item BABU, UMA - Food And Drug Administration(FDA)
item Proszkowiec-Weglarz, Monika
item BALAN, KANNAN - Food And Drug Administration(FDA)

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/19/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Transmission of Salmonella into table eggs could be via trans-ovarian (vertical) or trans-shell (horizontal) routes. CDC reported a multi state outbreak in the Midwest (2016) from consumption of eggs contaminated with Salmonella Oranienburg (SO), and this strain was closely related genetically to a 2015 outbreak linked to the same supplier. To determine if SO could colonize egg-forming tissues and contaminate eggs, groups of laying hens were infected with an oral dose of 107 (n = 25) and 109 (n = 27) colony forming unit (cfu) and evaluated after one (n = 10), two (n = 24) and four(n = 18) weeks. Standard microbiological methods were used to evaluate shedding of SO in the feces, contamination of eggshells and internal contents of eggs, and colonization in the spleen, ovaries, upper and lower oviduct. While presence of SO on eggshells were observed only when there were traces of fecal material, the bacteria was not recovered from internal egg contents (n = 748 eggs), and fecal shedding was observed over 4 weeks in birds gavaged with 107 (25%) and 109 (100%) cfu. Maximum colonization in spleen (83.3%), ovaries (29.2%), upper oviduct (20.8%), and lower oviduct (41.6%) were observed at 2 weeks post infection while at the end of 4 weeks there was no recovery of SO from the egg forming tissues. Since shell contamination and translocation of the bacteria into the albumen is a possibility, we assessed the persistence of SO within albumen by spiking with 103cfu/ml of SO and evaluating for up to 4 weeks under refrigerated conditions and observed 65% survival. Taken together, these studies showed that Salmonella Oranienburg did not cause egg contamination via vertical transmission, and colonization of egg forming tissues was limited to two weeks post infection. Future experimentation with additional strains of SO are needed to confirm the route of transmission into table eggs. Laying hens, Salmonella Oranienburg, gavage, tissue colonization, eggs