Risk factors for Salmonella Enteritidis and Typhimurium (DT104 and non-DT104) infections in The Netherlands:: predominant roles for raw eggs in Enteritidis and sandboxes in Typhimurium infections

Since 1996 Salmonella Typhimurium DT104 salmonellosis has increased in The Netherlands. This prompted a case-control study of risk factors for salmonellosis to inform transmission routes for this phage type. Cases were laboratory-confirmed patients with a Salmonella infection and controls were selected from population registries by frequency matching for age, sex, degree of urbanization and season. Cases and controls received a questionnaire on risk factors. Of the 1171 cases, 573 (49%) responded: 245 S. Enteritidis and 232 S. Typhimurium cases (both DT104 and non-DT104), of which 58 were DT104. Of the 10 250 controls, 3409 (33%) responded. Use of H2 antagonists [odds ratio (OR) 4(.)4, 95 % CI 1(.)6-12(.)2] and proton pump inhibitors (OR 4-2, 95 % CI 2(.)2-7(.)9), consumption of raw eggs (OR 3(.)1, 95 % CI 1(.)3-7(.)4) and products containing raw eggs (OR 1(.)8, 95 % CI 1(.)1-3(.)0) were associated with endemic S. Enteritidis infection. Risk factors for endemic S. Typhimurium infection were use of proton pump inhibitors (OR 8(.)3, 95 % CI 4(.)3-15(.)9), occupational exposure to raw meat (OR 3(.)0, 95 % CI 1(.)1-7(.)9), playing in a sandbox (for children aged 4-12 years) (OR 2(.)4, 95 % Cl 1(.)6-3(.)7), consumption of undercooked meat (OR 2(.)2, 95 % C1 1(.)1-4(.)1) and use of antibiotics (OR 1(.)9, 95 % CI 1(.)0-3(.)4). Use of proton pump inhibitors (OR 11(.)2, 95 % CI 3(.)9-31(.)9) and playing in a sandbox (OR 4(.)4, 95 % CI 1(.)8-10(.)7) were the only risk factors for S. Typhimurium DT104 salmonellosis. This study confirms known risk factors for salmonellosis. However, playing in a sandbox was a predominant new risk factor for S. Typhimurium salmonellosis in children [population attributable risk (PAR) 14%], and especially for S. Typhimurium DT104 (PAR 32%).