Epidemiology and Molecular Identification of Salmonella Infections in Children

OBJECTIVE: To explore the role of foods and the environment in the development of infections with Salmonella in infants and children. DESIGN: Case-controlled survey and the use of pulsed-field gel electrophoresis to establish DNA fingerprint patterns. SETTING: Ambulatory and hospitalized patients at a children's hospital. PATIENTS OR OTHER PARTICIPANTS: A consecutive sample of children younger than 4 years old who were infected with Salmonella and 3 age-matched controls per patient were to be surveyed. Of the 103 eligible cases of salmonellosis, 90 cases and 264 controls were included in the study. DATA ANALYSIS: Univariate analysis was done using the Mantel-Haenszel chi2 test or the Fisher exact test. The Bonferroni correction was used for multiple comparisons. DNA fingerprints were inspected for identical banding. RESULTS: Results demonstrated similar diets between cases and controls with the exception of more potato or macaroni salad or coleslaw consumption in the control group (P<.001). DNA fingerprints of Salmonella newport and Salmonella typhimurium demonstrated that all cases were due to unique isolates except in 5 instances involving 12 patients. Seven of these patients could be connected geographically. CONCLUSIONS: Most of the cases of salmonellosis in children younger than 4 years are of a sporadic nature and the major source of infection remains unidentified. For patients infected with identical isolates of Salmonella, a common food source could not be incriminated with the methods used. Environmental contamination or other sources of Salmonella are suggested by these epidemiological data.