title: An outbreak of salmonellosis among horses at a veterinary teaching hospital.
abstract: Between May 1996 and February 1997, 27 horses and a veterinary student at a veterinary teaching hospital developed apparent nosocomial Salmonella Typhimurium infection. The source of the multiple-drug resistant Salmonella Typhimurium was a neonatal foal admitted for treatment of septicemia. A high infection rate (approx 13% of hospitalized horses) coupled with a high case fatality rate (44%) for the initial 18 horses affected led to a decision to close the hospital for extensive cleaning and disinfection. Despite this effort and modification of hospital policies for infection control, 9 additional horses developed nosocomial Salmonella Typhimurium infection during the 6 months after the hospital reopened. Polymerase chain reaction testing of environmental samples was useful in identifying a potential reservoir of the organism in drains in the isolation facility. Coupled with clinical data, comparison of antimicrobial resistance patterns of Salmonella Typhimurium isolates provided a rapid initial means to support or refute nosocomial infection. Although minor changes in the genome of these isolates developed over the course of the outbreak, pulsed-field gel electrophoresis testing further supported that salmonellosis was nosocomial in all 27 horses.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824-1314, USA.
authors.forename: H C
authors.initials: HC
authors.lastname: Schott
authors.forename: S L
authors.initials: SL
authors.lastname: Ewart
authors.forename: R D
authors.initials: RD
authors.lastname: Walker
authors.forename: R M
authors.initials: RM
authors.lastname: Dwyer
authors.forename: S
authors.initials: S
authors.lastname: Dietrich
authors.forename: S W
authors.initials: SW
authors.lastname: Eberhart
authors.forename: J
authors.initials: J
authors.lastname: Kusey
authors.forename: J A
authors.initials: JA
authors.lastname: Stick
authors.forename: F J
authors.initials: FJ
authors.lastname: Derksen
mesh_terms: D000818:Animals; D003428:Cross Infection / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary*; D004196:Disease Outbreaks / Q000662:veterinary*; D004352:Drug Resistance, Microbial; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D005243:Feces / Q000382:microbiology; D005260:Female; D006734:Horse Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D006736:Horses; D006762:Hospitals, Animal; D006784:Hospitals, Teaching; D008297:Male; D008824:Michigan / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012475:Salmonella / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification; D012481:Salmonella Infections, Animal / Q000453:epidemiology* / Q000517:prevention & control; D012703:Serotyping / Q000662:veterinary