EPIDEMIC SALMONELLA-ENTERITIDIS INFECTION IN LOS-ANGELES-COUNTY, CALIFORNIA - THE PREDOMINANCE OF PHAGE TYPE-4

Between April and July 1994, 501 cases of Salmonella enteritidis infec tion were reported in Los Angeles County, California, nearly 5 times t he number reported between April and July 1993; of these, 422 (84%) we re sporadic (not related to known outbreaks). A case-control study was done to determine risk factors for sporadic illness; the distribution of 5 enteritidis phage types was evaluated. Case-patients (n = 58) we re county residents older than 1 year with culture-confirmed 5 enterit idis infection in August 1994. One to two acquaintance controls (n = 9 8) were matched to each case by age, sex, and race. Two risk factors-e ating raw or undercooked eggs (matched odds ratio [MOR] = 6.6; 95% con fidence interval [CI] = 1.9, 23.0) and eating in restaurants (MOR = 4. 9; 95% CI = 1.2, 19.4) in the 3 days before the onset of illness-remai ned significant in the conditional logistic regression model. Of 16 ra ndomly selected 5 enteritidis case-isolates, 15 (94%) were phage type 4, The reasons for the regional predominance of phage type 4, an S ent eritidis subtype recently associated with large and destructive increa ses in salmonellosis among poultry and humans in Britain and much of E urope, are unclear. To minimize human S enteritidis infection, food se rvice workers need frequent: training in the proper handling of raw Fo ods, eggs should be kept refrigerated during distribution and storage, and eggs should be cooked until the yolk is firm, particularly for pe rsons at the greatest risk for serious illness: pregnant women, elderl y persons, and those with compromised immune systems. Clinicians shoul d obtain stool specimens for culture from patients who present with di arrhea and fever or bloody diarrhea or who are possibly part of an out break.