A Mexican restaurant-associated outbreak of Salmonella Enteritidis type 34 infections traced to a contaminated egg farm.
In May 1996, the Georgia Division of Public Health was notified about a cluster of persons with Salmonella Enteritidis (SE) infections in Waycross, Georgia. A matched pair case-control study to determine risk factors for illness found a statistically significant association of SE infection with a history of having eaten at Restaurant A during the 5 days before onset of illness (relative risk = 13 [95% confidence interval (CI) = 3-62, P < 0.01]). In a second case-control study, to determine specific food exposures, consumption of a deep-fried Mexican dish (chile relleno) (4 of 21 cases vs. 0 of 26 controls, odds ratio undefined, 95% CI > 1.46, P = 0.034) was found to be significantly associated with SE infection. An environmental investigation found evidence of suboptimal food storage and cooking temperatures at Restaurant A; cross contamination of foods may have contributed to the low attributable risk identified for chile rellenos. Five of 37 Restaurant A food and environment specimens yielded SE strains. All five positive specimens were from chiles rellenos. Of the seven outbreak-associated strains (six patient isolates and one food isolate from Restaurant A) for which phage typing was conducted, all were phage type 34. A FDA traceback investigation through Restaurant A's single-egg supplier identified the potential source as three interrelated farms in South Carolina. Environmental culture from one of these farms yielded SE phage type 34. As a result of this outbreak, FDA helped institute a statewide egg quality-assurance programme in South Carolina to minimize SE contamination of eggs.
McNeil
M M
MM
Epidemiology and Prevention Branch, Division of Public Health, Georgia Department of Human Resources, Atlanta 30303, USA.
Sweat
L B
LB
Carter
S L
SL
Watson
C B
CB
Holloway
J T
JT
Manning
R
R
Altekruse
S F
SF
Blake
P A
PA
D000822:Animal Husbandry; D000818:Animals; D016022:Case-Control Studies; D002645:Chickens; D004196:Disease Outbreaks; D004531:Eggs / Q000382:microbiology*; D005260:Female; D005516:Food Microbiology; D005845:Georgia / Q000453:epidemiology; D006801:Humans; D008297:Male; D011201:Poultry Diseases / Q000382:microbiology; D012147:Restaurants / Q000592:standards; D012480:Salmonella Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000517:prevention & control; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology; D012477:Salmonella enteritidis / Q000145:classification / Q000302:isolation & purification*