Submitted to: United States Animal Health Association Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 30, 2002
Publication Date: October 20, 2002
Citation: Gast, R.K., Holt, P.S. 2002. Effect Of In Vivo Passage On The Frequency Of Egg Contamination By Salmonella Enteritidis In An Experimental Oral Infection Model in Laying Hens. United States Animal Health Association Proceedings. Technical Abstract: Experimental infection models are valuable for studying the deposition of Salmonella enteritidis inside eggs. Oral inoculation is often used in such experiments because it is believed to closely simulate naturally occurring S. enteritidis infections of chickens, but many recent oral infection studies have produced relatively low frequencies of egg contamination. A prior study demonstrated that intravenous and aerosol inoculation could also induce egg contamination, but at frequencies and in locations different from oral infection. A more recent trial considered the possibility that in vivo passage of an S. enteritidis strain might affect its ability to cause egg contamination in experimentally infected hens. The incidence of egg contamination was determined in groups of hens inoculated orally with either a phage type 13a S. enteritidis strain or with derivatives of this strain obtained by serial passage and re-isolation from tissues of infected hens. Passaged S. enteritidis isolates, especially those recovered from reproductive organs, were associated with a significantly higher incidence of egg contamination than the parent strain.