# Occult Serious Bacterial Infections in Neonates and Infants Up to Three Months of Age with Bronchiolitis: Are Invasive Cultures Required?

## TL;DR

This study examines the risk of serious bacterial infections in infants with bronchiolitis and fever, suggesting blood cultures are important but lumbar punctures may be unnecessary in some cases.

## Contribution

The study provides updated insights on the necessity of invasive cultures in infants with bronchiolitis and fever.

## Key findings

- Blood cultures had a 9.1% positivity rate in infants with bronchiolitis and fever.
- Cerebrospinal fluid cultures were negative in all tested infants.
- Infection markers did not reliably distinguish infants with positive from negative blood cultures.

## Abstract

(1) Background: The literature reports a low risk of serious bacterial infections (SBIs) in febrile infants presenting with bronchiolitis or respiratory syncytial virus infection, but current microbiological techniques have a higher accuracy. (2) Methods: We assessed the risk of SBIs in neonates and infants with bronchiolitis from 2021 to 2023. We also evaluated C-reactive protein, procalcitonin, and leukocyte values. (3) Results: We included 242 infants. Blood cultures (BCs) were performed in 66/242 patients, with a positivity rate of 9.1% (including one BC with Staphylococcus hominis, considered as a contaminant). The cerebrospinal fluid culture was performed in 6/242 patients, and the results were all negative. Infection markers did not discriminate infants with positive BCs from those with negative ones. (4) Conclusions: Blood cultures should be performed in neonates and young infants with bronchiolitis fever, as the sepsis risk is not negligible. Conversely, our proposed algorithm is to wait for the respiratory panel results before decision-making for a lumbar puncture. Further studies are needed to understand lumbar puncture requirements.