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Published on: February 9, 2011
Occult bacteremia from a pediatric emergency department: current prevalence, time to detection, and outcome
E R Alpern1, E A Alessandrini, L M Bell
1Division of Emergency Medicine, Children's Hospital of Philadelphia, Pennsylvania 19104, USA. alpern@email.chop.edu
Insights
Occult bacteremia in children is less common post-Haemophilus influenzae type b vaccine. Streptococcus pneumoniae is the main cause, usually resolving without antibiotics, with rare serious outcomes.
Area of Science:
- Pediatrics
- Infectious Diseases
- Microbiology
Background:
- Occult bacteremia, particularly in young children, has been a concern for bloodstream infections.
- The introduction of the Haemophilus influenzae type b (Hib) vaccine has potentially altered the epidemiology of bacteremia.
Purpose of the Study:
- To assess the current prevalence and characteristics of occult bacteremia in children.
- To identify the predominant pathogens and evaluate outcomes in the post-Hib vaccine era.
Main Methods:
- A retrospective cohort study of 5901 febrile children (2-24 months) with blood cultures was conducted.
- Exclusion criteria included immunosuppression, focal infection, or lumbar puncture.
- Prevalence, pathogen distribution, and time to positive culture were analyzed.
Main Results:
- Occult bacteremia prevalence was 1.9%, with Streptococcus pneumoniae being the most common pathogen (82.9%).
- Haemophilus influenzae was not identified as a cause.
- Cultures positive within 18 hours were more likely to be pathogenic; most pneumococcal cases resolved without antibiotics.
Conclusions:
- Occult bacteremia is less prevalent post-Hib vaccine, with S. pneumoniae dominating and typically resolving favorably.
- Continuous blood culture monitoring aids in pathogen identification.
- Serious adverse outcomes are rare, but updated epidemiology influences management strategies.
Objective:
To evaluate selected characteristics of occult bacteremia in the post-Haemophilus influenzae type b (HIB) vaccine era.
Methods:
A retrospective cohort study was performed involving 5901 children 2 to 24 months old with fever >/=39.0 degrees C evaluated with a blood culture at an urban tertiary care children's hospital emergency department (ED) between February 1993 and June 1996. Patients were excluded if immune-suppressed, diagnosed with a focal infection, evaluated by lumbar puncture, or admitted to the hospital during initial evaluation. Prevalence of occult bacteremia, distribution of current pathogenic organisms, and time to positive culture in a continuously monitored system were determined. All patients with cultures positive for pathogenic bacteria were reevaluated and serious adverse outcomes were documented.
Results:
The prevalence of occult bacteremia was 1.9% (95% confidence interval: 1.5%-2.3%). Streptococcus pneumoniae accounted for 82.9% of all pathogens and H influenzae was not a causative organism in this cohort. The mean time to positive culture was significantly shorter for pathogens compared with contaminants (14.9 hours vs 31.1 hours). A culture that was positive in
Conclusions:
Prevalence of occult bacteremia in the post-HIB vaccine era is lower than previously reported. S pneumoniae is the most common causative organism and resolves without parenteral antibiotics in the vast majority of cases. Continuously monitoring blood culture systems allow for early identification and can aid in differentiating contaminated from true pathogenic cultures by time to positive culture. Serious adverse outcome is an uncommon result of occult bacteremia. Updated epidemiology and microbiologic technology may impact the evaluation and treatment of children at risk for occult bacteremia.
