Antimicrobial treatment of occult bacteremia: a multicenter cooperative study

Area of Science:

• Pediatrics
• Infectious Diseases
• Clinical Microbiology

Background:

• Occult bacteremia, a serious bloodstream infection without an obvious source, poses diagnostic challenges in young children.
• Accurate prediction of bacteremia and effective empiric antimicrobial treatment are crucial for pediatric patient management.

Purpose of the Study:

• To define clinical and laboratory criteria for predicting occult bacteremia in children aged 3 to 36 months.
• To evaluate the efficacy of empiric broad-spectrum antimicrobial treatment with oral amoxicillin/potassium clavulanate versus intramuscular ceftriaxone.

Main Methods:

• Prospective, multicenter study involving children aged 3-36 months with high fever and elevated white blood cell counts without a clear infection focus.
• Children were randomized to receive either oral amoxicillin/potassium clavulanate or intramuscular ceftriaxone, with blood cultures obtained prior to treatment.
• Risk stratification based on fever severity and white blood cell (WBC) counts was performed.

Main Results:

• Out of 519 children, 11.6% had positive blood cultures, predominantly Streptococcus pneumoniae.
• High-risk criteria (fever ≥39.5°C and WBC ≥15 x 10^9/L) identified 16.6% positive cases, with positivity increasing with higher WBC counts (up to 42.9% for WBC ≥30 x 10^9/L).
• Lower-risk criteria (fever ≥39.5°C and WBC <15 x 10^9/L) showed significantly lower positivity rates (2.7%), with 0% positivity for WBC <10 x 10^9/L.
• Children treated with ceftriaxone were more likely to be afebrile within 24 hours compared to those on amoxicillin/potassium clavulanate.
• In culture-negative children, amoxicillin/potassium clavulanate was associated with more diarrhea and less clinical improvement.

Conclusions:

• Fever ≥39.5°C combined with WBC ≥15 x 10^9/L are strong predictors of occult bacteremia in children.
• Intramuscular ceftriaxone demonstrates superior efficacy over oral amoxicillin/potassium clavulanate for empiric treatment of febrile children with suspected bacteremia, showing faster fever resolution and fewer adverse effects.