89 - Etiology and risk factors of bacteremia in a pediatric emergency department in Canada

Poster Number: 89
Publication Number: 89.1547

Background: Pediatric bacteremia, notably in vulnerable groups like the immunocompromised, can cause severe health outcomes. Previous studies reported E. coli, S. aureus and S. pneumoniae as the most common pathogens. Studying pathogen predictors can guide focused enhancements.

Objective: We aimed to identify the causes and risk factors associated with various pathogens causing bacteremia in children in a Canadian emergency department (ED).

Design/Methods: This retrospective cohort study analyzed cases of bacteremia in children aged 0-18 in a Canadian tertiary pediatric hospital ED from 2018 to 2022. The primary outcome was the pathogen identified by blood culture. Children with non-pathologic species were excluded. Independent variables were age, sex, vaccination status, recent travel outside North America or Europe, presentation, risk factors (immunosuppression, previous bacteremia, internal device, sickle cell disease, heart malformation or failure, renal disease, age under 3 months), ED diagnosis and blood test results (absolute neutrophile count, C-reactive Protein (CRP)). Each chart was dual reviewed and inter-rater reliability was assessed. The primary analysis focused on pathogen prevalence, while associations between pathogens and independent variables were measured using Chi-square tests. Reviewing at least 250 cases was projected to yield narrow (+/- 6%) confidence intervals for proportions.

Results: There were 286 cases of bacteremia over 5 years. Patients had a median age of 43 months; 261 (92%) had fever, and 143 (48%) had a risk factor, primarily presence of internal devices (n=60; 21%), age under 3 months (n=49; 17%), immunosuppression (n=45; 16%) and previous bacteremia (n=28; 10%). Most had an elevated CRP level; the median (IQR) was 54 (117-22). The predominant pathogens were S. aureus (n=74; 26%), E. coli (n=44; 15%), non-typhoidal Salmonella (n=26; 9.1%), S. pneumoniae (n= 22; 7.7%) and group A Streptococcus (n=18; 6.3%). We found significant associations between independent variables and pathogens. Notably, 36% (n=31/86) of Staphylococcus spp. infections were among children with an internal device, 56% (n=18/32) of Salmonella spp. infections were in children who had recently traveled, 41% (n=18/44) of E. coli infections and 69% (n=11/16) of group B Streptococcus infections were in children < 3 months old (all p-values < 0.001).

Conclusion(s): Leading pathogens of pediatric bacteremia in this ED are S. aureus, E. coli, non-typhoidal Salmonella, and S. pneumoniae. While some predictors are associated with certain pathogens, over half the children with bacteremia had no identifiable risk factor.