title: Investigation of the distribution and control of Salmonella enterica serovar Enteritidis PT6 in layer breeding and egg production.
abstract: Investigations were carried out in a layer breeder hatchery, a layer parent rearing farm, a layer parent farm and in a commercial pullet rearing and cage layer farm where Salmonella enterica serovar Enteritidis (S. Enteritidis) PT6 had become established. PT6 was initially found in focal points in the hatchery, such as hatcher ventilation ducting, tray wash areas and waste areas, but improved disinfection was followed by a rapid disappearance of contamination. Several different phage types of S. Enteritidis were found in the hatchery but most of these proved to be genotypically identical with PT6. Investigations of contaminated layer breeder and rearing sites showed that the terminal disinfection programmes in place were effective in that no carry-over of infection occurred and the organism was rapidly eliminated from the organization. Infection with PT6 originating from chicks was investigated on a commercial pullet rearing farm. After several rounds of treatment with a fluoroquinolone antibiotic and competitive exclusion, no Salmonella was found in faeces or cloacal swabs but was present in dust in one of six houses. Sampling carried out after cleaning and disinfection confirmed clearance of the organism from the site, but infection did become established in a commercial laying house receiving the birds.
authors.affiliation: Department of Bacterial Diseases Veterinary Laboratories Agency -- Weybridge New Haw Surrey KT15 3NB, UK. r.h.davies@vla.defra.gsi.gov.uk
authors.forename: Robert
authors.initials: R
authors.lastname: Davies
authors.forename: Ernesto
authors.initials: E
authors.lastname: Liebana
authors.forename: Mark
authors.initials: M
authors.lastname: Breslin
mesh_terms: D000391:Air Microbiology; D000818:Animals; D002645:Chickens; D004203:Disinfection; D004391:Dust; D005243:Feces / Q000382:microbiology; D005260:Female; D006799:Housing, Animal; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D011201:Poultry Diseases / Q000382:microbiology* / Q000517:prevention & control* / Q000635:transmission; D021521:Ribotyping; D012481:Salmonella Infections, Animal / Q000517:prevention & control* / Q000635:transmission; D012477:Salmonella enteritidis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology
chemical_list: D004391:Dust