Risk factors for Salmonella gastroenteritis in children less than five years of age in Taiwan

BACKGROUND: Nontyphoid Salmonella spp. have been among the most common pathogens of acute gastroenteritis in children in Taiwan. However, the principal sources of transmission remain poorly defined. METHODS: A matched case-control study was conducted from January 2009 to October 2010. Cases were children aged 2-60 months who were hospitalized at 3 medical centers in Taiwan because of diarrhea and found to have culture-proven nontyphoidal Salmonella infection. Controls were healthy children or children with acute diseases other than gastroenteritis and matched to cases by age, gender, study site and enrollment date. RESULTS: A total of 396 cases and 930 matched controls were included for analysis. Multivariate analysis using conditional logistic regression identified contact with household members having diarrhea (matched odds ratio [mOR], 17.9; 95% confidence interval [CI]: 8.82-36.34; P < 0.0001), consumption of instant powdered milk (mOR, 2.04; 95% CI: 1.05-3.94; P = 0.0344), visits to health-care facilities (mOR, 1.66; 95% CI: 1.12-2.48; P = 0.0126) and consumption of purchased groundwater (mOR, 1.50; 95% CI: 1.06-2.11; P = 0.0214) within 1 week preceding enrollment as independent factors associated with increased risk of salmonellosis. Hand washing before meals (P = 0.0311), breastfeeding (P = 0.0370), consumption of chicken (P = 0.0019) and consumption of food prepared by caregivers (P = 0.0011) were protective against Salmonella infection. CONCLUSIONS: The principal transmission routes of Salmonella infection in Taiwanese children are person-to-person, waterborne and environmental contacts. The possibility of powdered milk and groundwater contamination of Salmonella cannot be excluded and requires further investigation.