Host RNA Expression Signatures in Young Infants with Urinary Tract Infection: A Prospective Study

Area of Science:

• Pediatric infectious diseases
• Molecular diagnostics
• Host-pathogen interactions

Background:

• Early diagnosis of infections in young infants is clinically challenging due to overlapping symptoms between bacterial and viral infections.
• Urinary tract infection (UTI) is common in infants, with decreasing rates of associated bacteremia.
• Host RNA expression signatures offer potential for differentiating bacterial from viral infections in this vulnerable population.

Purpose of the Study:

• To evaluate the utility of host RNA expression signatures in distinguishing bacterial (UTI without bacteremia) from viral infections in young infants.
• To assess the clinical performance of a specific two-gene host RNA expression signature.
• To investigate differential gene expression patterns in young infants with varying infection types.

Main Methods:

• Prospective study of 121 young infants presenting with infection symptoms across four Danish pediatric emergency departments.
• Whole blood samples were collected for differential gene expression analysis.
• Classification performance of a two-gene host RNA expression signature was evaluated.

Main Results:

• Several genes showed differential expression between infants with UTI without bacteremia and those with viral infections.
• A limited immunological response was observed in UTI without bacteremia compared to viral infections.
• The two-gene signature demonstrated limited classification performance, particularly for UTI without bloodstream involvement.

Conclusions:

• Host RNA expression signatures require further investigation and validation before clinical implementation for diagnosing infections in young infants.
• Consideration of urinary tract infections is crucial in young infants, even with limited host response markers.
• Current two-gene signatures may not be sufficiently robust for widespread clinical use in this demographic.