Haemophilus influenzae

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

Laboratory Testing

  • CDC - testing recommendations
  • Rapid antigen detection tests are available – utility is questionable
  • Otitis/sinusitis – clinical diagnosis; laboratory testing not routinely performed
  • Pneumonia – CBC, chest x-ray; consider sputum culture, blood culture
    • Positive upper respiratory culture does not necessarily establish organism as pathogen due to colonization
  • Cellulitis – wound culture; consider CBC, depending on clinical severity
  • Meningitis – CBC, spinal tap with CSF culture and gram stain, cell count
  • Immunoglobin deficiency testing
    • IgG testing for diphtheriatetanus and H. influenzae – determine vaccination response to diagnose immunoglobulin deficiency in patients with recurrent infection
      • Need pre- and post-vaccine titers (1 month after vaccination)

Differential Diagnosis

Haemophilus influenzae causes diseases predominantly affecting children.

Epidemiology

  • Incidence
    • WHO – 3,000,000 cases of serious disease annually
    • <1/100,000 for invasive disease in U.S. for children <5 years (CDC, National Notifiable Disease Surveillance System [NNDSS], 2015)
  • Age – usually in children; exception is pneumonia, which affects all ages
  • Transmission – respiratory droplet or direct contact with secretions

Risk Factors

Organism

  • Small, nonmotile, nonspore-forming, fastidious gram-negative bacterium
  • Requires medium containing X (porphyrins such as hemin) and V (nicotinamides such as NAD) factors for aerobic growth (eg, chocolate agar)
  • Six major typable serotypes (A-F)
    • Nontypeable strains are common and felt to be disease-causing
  • Colonizes human upper airways
    • Up to 80% of healthy people carry nontypeable H. influenzae

Clinical Presentation

  • Invasive disease significantly decreased since vaccine introduced
  • Otitis media, sinusitis, pharyngitis – usually children
  • Cellulitis – predominantly young children
  • Pneumonia – elderly, patients with chronic obstructive pulmonary disease (COPD), and patients who are immunocompromised
    • Common etiology of COPD exacerbations
  • Meningitis – often preceded by symptoms of upper respiratory tract infection, head trauma or surgery, CSF leak, otitis or sinusitis
  • Epiglottitis – usually children
  • Bacteremia (sepsis) – neonatal and maternal sepsis
  • Septic arthritis – usually children <2 years
  • Conjunctivitis – may occur in outbreaks, especially in daycare settings

Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Diphtheria, Tetanus, and H. Influenzae b Antibodies, IgG 0050779
Method: Quantitative Multiplex Bead Assay

Follow Up

If concentrations of IgG, IgM, and IgA range from low to normal and antibody deficiency is still strongly suspected, determine IgG subclass and response to protein antigens (eg, diphtheria, tetanus toxoid, influenzae)as well as to pure polysaccharide antigens (eg, unconjugated pneumococcal vaccine)

CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

Cell Count, CSF 0095018
Method: Cell Count/Differential

Respiratory Culture and Gram Stain 0060122
Method: Stain/Culture/Identification

Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification

Limitations

Testing is limited to the University of Utah Health Sciences Center only

Cerebrospinal Fluid (CSF) Culture and Gram Stain 0060106
Method: Stain/Culture/Identification

Related Tests

Guidelines

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Recommended Immunization Schedules for Persons Aged 0 Through 18 Years. United States, 2015. Centers for Disease Control and Prevention. Atlanta, GA [Last Updated Jul 2011; Accessed: Nov 2015]

General References

Rudan I, Campbell H. The deadly toll of S pneumoniae and H influenzae type b. Lancet. 2009; 374(9693): 854-6. PubMed

Ulanova M, Tsang RS W. Invasive Haemophilus influenzae disease: changing epidemiology and host-parasite interactions in the 21st century. Infect Genet Evol. 2009; 9(4): 594-605. PubMed

Watt JP, Wolfson LJ, O'Brien KL, Henkle E, Deloria-Knoll M, McCall N, Lee E, Levine OS, Hajjeh R, Mulholland K, Cherian T, Hib and Pneumococcal Global Burden of Disease Study Team. Burden of disease caused by Haemophilus influenzae type b in children younger than 5 years: global estimates. Lancet. 2009; 374(9693): 903-11. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology®

Medical Reviewers

Last Update: January 2016