Blood cultures in sick children

Area of Science:

• Pediatric Infectious Diseases
• Clinical Microbiology
• Laboratory Medicine

Background:

• Blood cultures (BCs) are essential for diagnosing bloodstream infections in critically ill children.
• Previous studies, including adult patient audits, have indicated high contamination rates in BCs, often by coagulase-negative staphylococci (CoNS).
• Understanding contamination rates and common pathogens in pediatric populations is vital for appropriate patient management.

Purpose of the Study:

• To determine the rates of blood culture contamination in children at a tertiary-level children's hospital.
• To identify common pathogenic organisms responsible for bloodstream infections in pediatric patients.
• To compare contamination rates between different age groups within the pediatric population.

Main Methods:

• Retrospective analysis of 47,677 blood culture results from children admitted between 2008 and 2012.
• Data extracted from the National Health Laboratory Service database.
• Analysis of pathogenic versus contaminated growth, stratified by age (<1 year vs. >1 year), using Epi Info version 3.5.1.

Main Results:

• Overall contamination proportion ranged from 5.9% to 7.2% annually.
• Coagulase-negative staphylococci (CoNS) accounted for 53.8% of all contaminated BCs.
• Children under 1 year had significantly higher contamination rates (8.7%) compared to older children (4.7%). Pathogenic organisms were found in 6.2% of BCs, with a notable increase in Gram-negative organisms and a decrease in Streptococcus pneumoniae.

Conclusions:

• Blood culture contamination rates in this pediatric cohort were unacceptably high.
• The findings underscore the critical need for strict adherence to sterile techniques during blood culture specimen collection.
• Monitoring trends in bloodstream pathogens, such as the rise in Gram-negative bacteria, is important for antimicrobial stewardship.