Pneumococci (synonym: Streptococcus pneumoniae; ICD-10 J13: Pneumonia due to Streptococcus pneumoniae) are gram-positive bacteria of the species Streptococcus pneumoniae, which morphologically belong to the group of diplococci (= stored in pairs).
Pneumococci occur in humans, monkeys, rats and other rodents. In up to 40% of healthy children and up to 10% of the healthy adult population, the bacterium is present in the mucosa (mucous membrane) of the nasopharynx (nasopharynx) and can therefore also be passed on by healthy individuals.
Pneumococci most commonly cause pneumonia (inflammation of the lungs), but meningitis (meningitis) and acute otitis media (AOM; acute inflammation of the middle ear) are also among the infectious diseases caused by pneumococci.
Pneumococcal disease is divided into the following clinical forms:
- Invasive pneumococcal disease (IPD).
- Bacteremia (introduction of bacteria into the bloodstream).
- Meningitis
- Non-invasive (mucosal) pneumococcal disease* .
- Pneumonia (pneumonia)
- Acute otitis media (AOM)
- Sinusitis
* Noninvasive forms of pneumococcal disease can develop into invasive forms (e.g., pneumonia when accompanied by bacteremia).
Occurrence: The infection occurs worldwide.
Transmission of the pathogen (route of infection) occurs via droplets produced by coughing and sneezing and absorbed by the other person via the mucous membranes of the nose, mouth and possibly the eye (droplet infection) or aerogenically (through droplet nuclei (aerosols) containing the pathogen in the exhaled air), especially in poorly ventilated and crowded rooms.
Human-to-human transmission: Yes.
The incidence (frequency of new cases) of community-acquired pneumonia (AEP; CAP = community acquired pneumonia) is about 3 cases per 1,000 population per year (in Germany: for all age groups; and about 8/1,000 in patients ≥ 60 years); about 40% of infections are caused by Streptococcus pneumoniae.
Course and prognosis: course and prognosis depend on the age of the person with the disease and especially on the type of pneumococcal strain. In younger, otherwise healthy individuals, the disease usually progresses without complications. In persons with immunodeficiency (immune deficiency), severe courses with complications can occur. The course can also become life-threatening in infants, young children, persons suffering from chronic diseases.
Note: After a double infection with Streptococcus pneumoniae and influenza viruses (influenza A virus), the disease is always particularly severe, often even lethal.
The lethality (mortality in relation to the total number of people suffering from the disease) is approx. 5-8 %. The lethality of community-acquired pneumonia (AEP) in the hospital or in the first 30 days is on average 13-14%. It can increase to over 40% in severe and septic disease. In the presence of underlying diseases such as diabetes mellitus or chronic heart disease, the lethality of pneumococcal infection can increase up to 30%.
The CRB-65 and CURB-65 prognosis scores have proven useful for assessing prognosis (see “Physical examination“).
Notice: Invasive pneumococcal disease has the fourth highest burden of disease of all infectious diseases after HIV infections.
Vaccination: vaccination against pneumococcus is available and recommended by the “Standing Commission on Vaccination” (STIKO) for all children (from 2 months of age) and people over 60 years of age.