title: The pandemic of Salmonella enteritidis phage type 4 reaches Utah: a complex investigation confirms the need for continuing rigorous control measures.
abstract: In 1995, Salmonella Enteritidis (SE) cases in the state of Utah increased fivefold. Isolates were identified as phage type 4 (PT4). Risk factors and sources of infection were investigated in two case-control studies, a traceback of implicated foods, and environmental testing. Forty-three patients with sporadic infections and 86 controls were included in a case-control study of risk factors for infection. A follow-up case-control study of 25 case and 19 control restaurants patronized by case and control patients examined risks associated with restaurant practices. In the first case-control study, restaurant dining was associated with illness (P = 0.002). In the follow-up case-control study, case restaurants were likelier to use > 2000 eggs per week (P < 0.02), to pool eggs (P < 0.05), and to use eggs from cooperative 'A' (P < 0.009). Eggs implicated in separately investigated SE PT4 outbreaks were traced to cooperative 'A', and SE PT4 was cultured from one of the cooperative's five local farms. We conclude that SE PT4 transmitted by infected eggs from a single farm caused a fivefold increase in human infections in Utah.
authors.affiliation: Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
authors.forename: J
authors.initials: J
authors.lastname: Sobel
authors.forename: A B
authors.initials: AB
authors.lastname: Hirshfeld
authors.forename: K
authors.initials: K
authors.lastname: McTigue
authors.forename: C L
authors.initials: CL
authors.lastname: Burnett
authors.forename: S
authors.initials: S
authors.lastname: Altekruse
authors.forename: F
authors.initials: F
authors.lastname: Brenner
authors.forename: G
authors.initials: G
authors.lastname: Malcolm
authors.forename: S L
authors.initials: SL
authors.lastname: Mottice
authors.forename: C R
authors.initials: CR
authors.lastname: Nichols
authors.forename: D L
authors.initials: DL
authors.lastname: Swerdlow
mesh_terms: D000328:Adult; D001434:Bacteriophage Typing; D016022:Case-Control Studies; D004269:DNA, Bacterial / Q000032:analysis; D003967:Diarrhea / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D004196:Disease Outbreaks; D004531:Eggs / Q000382:microbiology; D005260:Female; D005516:Food Microbiology; D006801:Humans; D008297:Male; D012147:Restaurants / Q000592:standards / Q000706:statistics & numerical data*; D012307:Risk Factors; D012478:Salmonella Food Poisoning / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D012477:Salmonella enteritidis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D011795:Surveys and Questionnaires; D014589:Utah / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial