Clinical characteristics and risk factor analysis of invasive non-typhoidal Salmonella infection in children

To investigate the clinical characteristics of invasive non-typhoidal Salmonella (iNTS) infection in children and systematically analyze associated factors.

Clinical data, including epidemiological information, demographic characteristics, clinical manifestations, laboratory test results, bacterial strain characteristics, and antimicrobial susceptibility profiles, were collected from pediatric patients hospitalized with non-typhoidal Salmonella (NTS) infection at Fujian Maternal and Child Health Hospital or Fujian Children's Hospital from January 2013 to December 2022. Patients were categorized into iNTS and non-iNTS infection groups based on bacterial culture sources. Univariate comparisons explored clinical features associated with iNTS infection. Multivariate logistic regression and receiver operating characteristic (ROC) curve analyses identified associated factors for iNTS infection. Subgroup analysis was performed by age stratification (infants: <1 year, toddlers: 1-<3 years, and older children: ≥3 years).

A total of 314 children with NTS infection were included, of whom 38 (38/314, 12.1%) had iNTS infection. Disease onset was predominantly observed in infants and young children, with higher incidence during summer and autumn. Univariate and multivariate logistic regression analyses identified pre‑hospitalization fever duration (P<0.001, OR = 1.235, 95%CI 1.122-1.359), LDH level (P = 0.027, OR = 1.003, 95%CI 1.000-1.006), and Salmonella serogroup C1 (P = 0.013, OR = 4.392, 95%CI 1.373-14.049) as independent risk factors for iNTS infection. The combined ROC curve of these three factors showed an area under the curve (AUC) of 0.831, sensitivity of 76.3%, and specificity of 75.4%. In the infant subgroup, pre‑hospitalization fever duration (P = 0.006, OR = 1.205, 95%CI 1.055-1.376) and anemia (P = 0.039, OR = 2.884, 95%CI 1.053-7.897) were significantly associated with iNTS infection, yielding a combined AUC of 0.838.

In hospitalized pediatric patients with NTS infection, pre‑hospitalization fever duration, LDH level, and Salmonella serogroup C1 are independent factors associated with iNTS infection, with good diagnostic performance (AUC = 0.831). In infants, anemia is also independently associated (combined AUC = 0.838). Epidemiological data, demographic characteristics, clinical manifestations, and routine laboratory tests provide preliminary clinical clues; however, further prospective studies are needed.