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Description of Streptococcus Pneumoniae

Streptococcus pneumoniae is a bacterium that is commonly found in the nasopharynx---the portion of the upper throat that lies directly behind the nose. It is responsible for a wide variety of infections, the most notable of which is pneumonia. An article in the October 2001 issue of the Journal of Bacteriology said the bacterium is responsible for roughly 1.1 million deaths worldwide each year.

  1. Illnesses

    • The Centers for Disease Control and Prevention (CDC), which reports that there are more than 90 serotypes of this bacterium, says that it is the cause of not just pneumonia but a number of other infections as well. These include bacteremia, meningitis, osteomyelitis and arthritis, otitis media (an infection of the middle ear), peritonitis and sinusitis. The CDC reports that before 2000, the bacterium each year caused between 100,000 and 135,000 hospitalizations for pneumonia; 66,000 cases of invasive disease, including about 3,300 cases of meningitis; and approximately 6 million cases of otitis media.

    Infection Rate Cut Sharply

    • The introduction of the 7-valent pneumococcal conjugate vaccine (PCV) in the early 2000s and its widespread administration to infants in the United States has sharply cut the childhood rate of Streptococcus pneumoniae infections. According to the Immunization Action Coalition, more than 30 states require that children receive the vaccine before they are allowed to be enrolled in a day care program. For anyone is who is at least 2 years old, there is a 23-valent pneumococcal polysaccharide vaccine (PPV) that also protects against infection caused by Streptococcus pneumoniae. PPV cannot be used in children younger than 2.

    Vaccines' Effectiveness

    • Although the PCV and PCV vaccines have sharply reduced the rate of infections caused by the ever-present Streptococcus pneumoniae, neither is effective against all known serotypes of the bacterium. The CDC reports that the pediatric vaccine, PCV, protects against roughly 80 percent of the serotypes known to cause disease, while PPV is effective against 88 percent of the problematic serotypes. Further complicating matters is the appearance of antibiotic-resistant strains of the bacterium.

    High-Risk Groups

    • The CDC says that the risk of contracting an infection caused by Streptococcus pneumoniae is greatest among children younger than 2 and the elderly. High concentrations of infection have been reported in institutional settings, including day care centers and nursing homes. Also at increased risk are African-Americans, Alaskan natives, Native Americans and people with underlying medical conditions, such as sickle cell disease and HIV.

    Complications

    • Complications of Streptococcus pneumoniae infections include hearing impairment in patients who have suffered recurrent middle ear infections; neurological damage or learning disabilities in those who had meningitis; and joint and bone damage in patients who have had arthritis or osteomyelitis. The CDC reports a death rate of about 14 percent among adults hospitalized with invasive disease caused by Streptococcus pneumoniae.

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