eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease

Pneumococcal Bacteremia

Author: Martha L Miller, MD, Associate Professor of Pediatrics, Division of Infectious Diseases, University of New Mexico School of Medicine
Contributor Information and Disclosures

Updated: May 5, 2009

Introduction

Background

Streptococcus pneumoniae, or pneumococcus, is an encapsulated gram-positive bacterium that is a major cause of common upper respiratory infections and serious invasive infections.

In the United States, pneumococcus is responsible for 3,000 cases of meningitis, 50,000 cases of bacteremia, and 500,000 cases of pneumonia per year. Additionally, in the United States, pneumococcus is the most common cause of bacterial meningitis and bacterial pneumonia in children younger than 2 years. Many patients with pneumococcal bacteremia have evidence of focal infection at their initial presentation, but a phenomenon of occult bacteremia (OB) was recognized 3 decades ago and has been the featured topic of pediatric journals since then.

The occult bacteremia phenomenon has been defined clinically as bacteremia occurring in a healthy-appearing febrile child without evidence of focal bacterial infection or signs of sepsis. Although S pneumoniae is the most common cause of occult bacteremia, much of the research and writing about occult bacteremia preceded the near elimination (by introduction of an effective vaccine) of another major cause of occult bacteremia, Haemophilus influenzae type B.

The identification of patients at risk for bacteremia and strategies to prevent secondary complications (eg, meningitis, pneumonia, septic arthritis, osteomyelitis, cellulitis) has been the focus of the occult bacteremia literature.1 After the introduction of the heptavalent pneumococcal vaccine in the United States, the rates of invasive disease have markedly diminished (an estimated 85% reduction for the 7 serotypes covered by the vaccine).

Pathophysiology

Pneumococcus commonly and asymptomatically colonizes the upper respiratory tract of children. Breakdown of the normal mucosal barriers is considered to be the initial step towards invasion of the bloodstream.

Frequency

United States

Previous studies have suggested that 3-5% of children aged 3-36 months who have a fever higher than 39°C and no source of infection have occult bacteremia, and a recent estimate of pneumococcal bacteremia in the post– H influenzae era found a prevalence of 1.6%. Since the introduction of the universal pneumococcal vaccination, the incidence has most recently been estimated to be approximately 0.5%.

Mortality/Morbidity

Although the previous writings have indicated that most cases of pneumococcal bacteremia self-resolve, data are insufficient to make such a claim. Only one prospective study reported a no antibiotic treatment group, and 2 out of 5 untreated patients developed meningitis. In retrospective studies, most patients no longer had bacteremia upon reevaluation, but many patients still had fever and were treated subsequently with antibiotics; therefore, one is unable to state that the bacteremia self-resolved.

Ten percent of patients with bacteremia develop focal complications. Meningitis is the complication of 3-6% of patients with pneumococcal bacteremia. Of patients who develop meningitis, approximately 15% die, and 25% survive with neurologic deficits.

Pneumococcus is a major cause of sepsis in immunocompromised patients, including those with malignancy, asplenia (eg, sickle cell disease), and HIV.

Age

Occult pneumococcal bacteremia is most common in children aged 3-36 months. Pneumococcal bacteremia can occur in older patients with focal pneumococcal infection and in immunocompromised patients.

Clinical

History

Approximately 40% of patients with pneumococcal bacteremia have fever for less than 1 day, and 82% of patients have fever for less than 2 days.

Physical

By definition, occult pneumococcal bacteremia occurs in a healthy-appearing child with the absence of signs of focal infection or sepsis. Observation scales are not helpful for identifying patients with occult bacteremia (OB).

Patients with recognizable viral illnesses, such as stomatitis, croup, bronchiolitis, varicella, and mononucleosis, are at lower risk for pneumococcal bacteremia. In comparison to occult bacteremia, pneumococcal bacteremia should be suspected in patients with sepsis syndrome or focal bacterial infections, such as pneumonia or meningitis.

Causes

Although S pneumoniae is the most common cause of OB, much of the research and writing about OB preceded the near elimination (by introduction of an effective vaccine) of another major cause of OB, H influenzae type B.

More on Pneumococcal Bacteremia

Overview: Pneumococcal Bacteremia
Differential Diagnoses & Workup: Pneumococcal Bacteremia
Treatment & Medication: Pneumococcal Bacteremia
Follow-up: Pneumococcal Bacteremia
Multimedia: Pneumococcal Bacteremia
References
Further Reading
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References

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  2. Picazo JJ. Management of antibiotic-resistant Streptococcus pneumoniae infections and the use of pneumococcal conjugate vaccines. Clin Microbiol Infect. Apr 2009;15 Suppl 3:4-6. [Medline].

  3. Feldman C, Anderson R. Therapy for pneumococcal bacteremia: monotherapy or combination therapy?. Curr Opin Infect Dis. Apr 2009;22(2):137-42. [Medline].

  4. Pneumonia hospitalizations among young children before and after introduction of pneumococcal conjugate vaccine--United States, 1997-2006. MMWR Morb Mortal Wkly Rep. Jan 16 2009;58(1):1-4. [Medline].

  5. Wilkinson M, Bulloch B, Smith M. Prevalence of occult bacteremia in children aged 3 to 36 months presenting to the emergency department with fever in the postpneumococcal conjugate vaccine era. Acad Emerg Med. Mar 2009;16(3):220-5. [Medline].

  6. [Best Evidence] Jansen AG, Sanders EA, Hoes AW, van Loon AM, Hak E. Effects of influenza plus pneumococcal conjugate vaccination versus influenza vaccination alone in preventing respiratory tract infections in children: a randomized, double-blind, placebo-controlled trial. J Pediatr. Dec 2008;153(6):764-70. [Medline].

  7. Alpern ER, Alessandrini EA, Bell LM, et al. Occult bacteremia from a pediatric emergency department: current prevalence,time to detection, and outcome. Pediatrics. Sep 2000;106(3):505-11. [Medline].

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  24. Sniadack DH, Schwartz B, Lipman H, et al. Potential interventions for the prevention of childhood pneumonia: geographic and temporal differences in serotype and serogroup distribution of sterile site pneumococcal isolates from children-- implications for vaccine strategies. Pediatr Infect Dis J. Jun 1995;14(6):503-10. [Medline].

  25. Teach SJ, Dryja DM, Tristram D. Pneumococcal bacteremia and focal infection in young children. Clin Pediatr (Phila). Sep 1998;37(9):531-5. [Medline].

  26. Teach SJ, Fleisher GR. Efficacy of an observation scale in detecting bacteremia in febrile children three to thirty-six months of age, treated as outpatients. Occult Bacteremia Study Group. J Pediatr. Jun 1995;126(6):877-81. [Medline].

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Keywords

pneumococcal bacteremia, Streptococcus pneumoniae bacteremia, Streptococcus pneumoniae, S pneumoniae, pneumococcus, gram-positive sepsis, occult bacteremia, OB, meningitis, bacteremia, pneumonia, upper respiratory infection, URI, septic arthritis, osteomyelitis, cellulitis, sickle cell disease, HIV, stomatitis, croup, bronchiolitis, varicella, mononucleosis, treatment, diagnosis

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Contributor Information and Disclosures

Author

Martha L Miller, MD, Associate Professor of Pediatrics, Division of Infectious Diseases, University of New Mexico School of Medicine
Disclosure: Nothing to disclose.

Medical Editor

David Jaimovich, MD, Chief Medical Officer, Joint Commission International and Joint Commission Resources
David Jaimovich, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Larry I Lutwick, MD, Professor of Medicine, State University of New York, Downstate Medical School; Director, Infectious Diseases, Veterans Affairs New York Harbor Health Care System, Brooklyn Campus
Larry I Lutwick, MD is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

CME Editor

Robert W Tolan Jr, MD, Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine
Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility
Disclosure: GlaxoSmithKline Honoraria Speaking and teaching; MedImmune Honoraria Speaking and teaching; Merck Honoraria Speaking and teaching; sanofi pasteur Honoraria Speaking and teaching; Baxter Healthcare Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD, Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine
Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association
Disclosure: None None None

 
 
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