Risk factors for sporadic infection with non-typhoidal Salmonella among children under five years of age in urban area of Kunming City: a matched case-control study

Background With the urbanization process in China, improving clean water and proper sanitation has reduced fecal-oral transmitted infectious diseases. However, non-typhoidal Salmonella (NTS) infection is relatively prevalent among children. The study aims to explore risk factors associated with NTS infection in young children in urban city areas. Methods An age- and sex-matched, case-control study was conducted from May 2022 through April 2023. One hundred one cases and 202 controls who resided in the urban area of Kunming City were interviewed using a standardized questionnaire on exposures three days before illness. The association of each exposure with infection status was determined using conditional logistic regression. Results The proportion of diagnoses for NTS infections was the highest in the rainy season (May to October) each year. S. Typhimurium was the most common serotype (64.5%), followed by Enteritidis (11.8%). Permanently storing raw eggs in a refrigerator, no separate cutting board for raw and cooked food, and more than one child living together in the same family were found to be associated with 4.73, 10.38, and 2.69 to 10.16 times increased risk of NTS infections in family children, respectively. Conclusions These risk factors are closely related to hygiene habits. Thus, family members should practice good hand hygiene and use correct food storage and handling methods in the domestic setting.