Risk factors for sporadic infection with Salmonella Infantis: a matched case-control study

Abstract

This matched case-control study investigated the risk factors for sporadic Salmonella Infantis infection in 263 affected children and 263 age-, gender- and neighbourhood-matched controls. Information about exposure to potential risk factors was obtained via telephone interview and evaluated by conditional logistic regression analysis. Age groups ≤ 1 year (n=77) and >1 year (n = 186) were analysed separately. Of those aged ≤ 1 year, breastfeeding was a significant protective factor against infection [matched odds ratio (mOR) 0.24, 95% confidence interval (CI) 0.10-0.59, P < 0.01]. In the older group, consumption of eggs (mOR 1.87, 95% CI 1.00-3.49, P = 0.05) was a significant risk factor and thawing chicken in water (mOR 2.55, 95% CI 0.94-6.91, P = 0.07) was borderline risk factor, while consumption of carrots (mOR 0.46, 95% CI 0.26-0.83, P < 0.01), drinking tap water (mOR 0.44, 95% CI 0.22-0.85, P = 0.02), religious lifestyle (mOR 0.40, 95% CI 0.21-0.74, P < 0.01) and having a high number of children in the household (mOR 0.72, 95% CI 0.58-0.88, P < 0.01) were significant protective factors. Consumers should avoid eating undercooked eggs and food handlers should be educated regarding proper handling and cooking of eggs. Breastfeeding should be strongly encouraged by public health authorities. The public must be educated on stringent hygiene practices, especially proper cooking of eggs to reduce infection rates.