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Streptococcus pneumoniae (pneumonoccus) 

The leading cause of pneumonia mortality globally, pneumococcus kills 500,000 children under 5 worldwide each year. In the US, an estimated 400,000 hospitalizations occur annually, and 18 million visits to the pediatrician. Over 1/2 of bacterial meningitis in the US are caused by pneumococci, causing an estimated 2000 cases each year with 8% fatality in children and 22% in adults.

The Pathogen

Streptococcus pneumoniae (S. Pneumoniae or pneumococcus) are lancet-shaped, gram-positive, facultative anaerobic bacteria with over 90 known serotypes. Most S. pneumoniae serotypes can cause disease, but only a minority of serotypes produce the majority of pneumococcal infections. Pneumococci are common inhabitants of the respiratory tract and may be isolated from the nasopharynx of 5–90% of healthy persons, depending on the population and setting. Pneumococci have several components that enhance it's ability to cause disease, including: Capsule, which allows for survival in the blood; Pneumolysin, a toxin that causes host cell lysis; and Cell Wall Components, which when released by Autolysin are thought to cause the majority of symptoms in the host, among other factors.

Pneumococcal Infection

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Pneumococcus cause many types of illness including: pneumonia (infection in the lung), bacteremia (blood stream infection), meningitis (infection in the brain/spinal cord), ear infections, and sinus infections. Pneumonia is the most common in adults, with a short incubation of 1-3 days with abrupt onset of fever or chills and rigor. 25-30% of these cases also develop bacteremia, with 5-6% fatality. Pneumococcus also causes 20% of acute otitis media, an ear infection that occurs in 60% of children less than 1 year old at least once. 


Antiobiotic Resistant Pneumococcus

In the 1990's ~60,000 cases of invasive pneumococcal disease occured each year, with up to 40% caused by bacteria resistant to at least 1 antibiotic and increasingly becoming resistant to 3 or more antibiotic drug classes. In 1993 a pneumococcal vaccine was introduced with more than 90% efficacy in children under 5. After the introduction of this vaccine, cases of invasive disease decreased, antibiotic use was reduced, and the prevalence of AMR pneumococcus declined. In 2015, invasive disease was down to ~30,000 cases, with resistant bacteria in 30% of cases.