Microbial characteristics and risk factors in PICU with freshwater drowning-associated pneumonia

Drowning-associated pneumonia (DAP) is the most common infectious complication in drowning patients admitted to the pediatric intensive care unit (PICU). We aim to describe the clinical features, emergency interventions, microbiological characteristics, and antibacterial treatment strategies for children who have drowned, ando analyze the correlation between these factors and their prognosis. This retrospective study enrolled 141 children admitted to the PICU following freshwater drowning between 2019 and 2024. The cohort was stratified by the occurrence of DAP, with comparisons conducted on baseline characteristics, clinical outcomes, pathogen spectrum, and treatment. A logistic regression model was employed to identify risk factors for 28-day post-discharge mortality. Among the 141 pediatric patients admitted to the PICU due to drowning, 71 were diagnosed with DAP and 70 without (Non-DAP). No significant differences were found in the frequency distributions between the two groups when comparing time intervals from submersion to chest compressions and the duration of chest compressions, using a 5-minute cutoff (P > 0.05). Although the DAP group experienced significantly longer hospital and PICU stays, they demonstrated a markedly lower mortality rate at discharge (18.31% vs 41.43%, P = 0.003) and 28-day post-discharge (22.54% vs. 47.14%, P = 0.002) compared to the Non-DAP group. The Pediatric Risk of Mortality (PRISM) score  and hypoxic-ischemic encephalopathy (HIE) were independent risk factors, while a longer length of hospital stay was served as a protective factor for 28-day post-discharge mortality. Microbiological analysis showed that the most commonly detected pathogens were Staphylococcus aureus and Mycoplasma pneumoniae, Candida albicans and rhinovirus. Combination therapy was significantly more frequent in the DAP group (63.38% vs 41.51%), and the use of linezolid was significantly higher in this group than in the Non-DAP group (36.62% vs. 8.57%, P = 0.001).

DAP is a frequently observed complication in PICU patients following drowning incidents, but it is not associated with increased mortality among these children. Staphylococcus aureus is a frequently identified pathogen in pediatric DAP, underscoring the need for empirical antibiotic therapy to cover Gram-positive bacteria.

• Drowning is a leading cause of pediatric ICU admission. • Drowning-associated pneumonia is common and poses diagnostic challenges, prompting the use of empiric broad-spectrum antibiotics.

• In this pediatric cohort, DAP was associated with longer hospital and PICU stays, but not with increase mortality. • Staphylococcus aureus was the most prevalent pathogen, underscoring the need for Gram-positive bacterial coverage in empirical therapy.