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Streptococcus pneumoniae colonization, bacteremia, and immune response among persons with human immunodeficiency

E N Janoff1, J O'Brien, P Thompson

  • 1Department of Medicine, VA Medical Center, Minneapolis, MN 55417.

The Journal of Infectious Diseases
|January 1, 1993
PubMed

Insights

Human immunodeficiency virus (HIV) infection is linked to higher rates of pneumococcal bacteremia. This may be due to lower CD4+ T cell counts and weakened immune responses, not increased exposure to Streptococcus pneumoniae.

Area of Science:

  • Immunology
  • Infectious Diseases
  • Public Health

Background:

  • Invasive pneumococcal infections are common in men with human immunodeficiency virus (HIV).
  • The prevalence of Streptococcus pneumoniae pharyngeal colonization was similar between HIV-infected and HIV-seronegative men.
  • HIV-infected individuals experience higher rates of pneumococcal bacteremia.

Purpose of the Study:

  • To investigate the reasons behind the increased prevalence of pneumococcal bacteremia in HIV-infected individuals.
  • To compare pharyngeal colonization rates of Streptococcus pneumoniae between HIV-infected and HIV-seronegative men.
  • To assess the humoral immune response to Streptococcus pneumoniae in HIV-infected patients.

Main Methods:

  • Prevalence of Streptococcus pneumoniae pharyngeal colonization was assessed in HIV-infected and HIV-seronegative men.
  • Pneumococcal bacteremia cases were analyzed in HIV-infected men.
  • Serum killing activity, a measure of humoral response, was compared between bacteremic HIV-infected patients and HIV-seronegative controls.

Main Results:

  • Pharyngeal colonization rates did not differ significantly between HIV-infected (14%) and HIV-seronegative (9%) men.
  • Sixteen HIV-infected men developed pneumococcal bacteremia, representing a significant proportion of cases in men aged 16-55.
  • Impaired serum killing activity against Streptococcus pneumoniae was observed in bacteremic HIV-infected patients compared to controls.

Conclusions:

  • Increased pneumococcal bacteremia in HIV-infected patients is associated with low CD4+ T cell counts and impaired humoral immunity.
  • The higher incidence of bacteremia is likely due to weakened immune responses rather than increased exposure to Streptococcus pneumoniae.
  • These findings highlight the importance of immune status in pneumococcal infection susceptibility among HIV-infected individuals.

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