Bacterial meningitis (synonyms: bacterial leptomeningitis; bacterial meningitis; meningeal infection; ICD-10-GM G00.-: bacterial meningitis, not elsewhere classified) is a form of meningitis caused by bacteria. The disease can lead to a severe course of disease in a short time. Since the outer part of the brain is usually also affected, the correct name should actually be meningoencephalitis (combined inflammation of the brain (encephalitis) and the meninges (meningitis)). Bacterial meningitis is an absolute medical emergency and must be treated immediately in hospital! The possible pathogen depends on the environment and age:
- Acquired ambulatory
- Infants <1 month of age: E. coli, group B streptococci, Listeria.
- Infants: Haemophilus influenzae (in the absence of vaccination protection), meningococci* (> 50), pneumococci (Streptococcus pneumoniae) and others
- Adults: pneumococci (about 50%), meningococci (Neisseria meningitidis) (about 30%), Listeria (especially in the elderly, immunodeficiency (defense weakness)), Mycobacterium tuberculosis (in HIV patients) and others
.
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- Hospital-acquired (nosocomial).
- Enterobacteriaceae, Pseudomonas aeruginosa, Staphylococci.
- Patients with immunosuppression (immunodeficiency).
- Additionally: Listeria monocytogenes, Cryptococcus neoformans and others, M. tuberculosis (tuberculous meningitis, TBM) and others
.
The most common causative agents of bacterial meningoencephalitis in adults are:
- Streptococcus pneumoniae and Neisseria meningitidis.
- Listeria monocytogenes (<5% of cases).
- Staphylococci (1-9% of cases).
- Gram-negative enterobacteria and Pseudomonas aeruginosa (<10% of cases).
- Haemophilus influenzae (1-3 %).
The most common causative agents of suppurative meningoencephalitis in children are:
The most common causative agents of suppurative meningoencephalitis in neonates are:
- Streptococcus agalactiae (group B streptococci) and Listeria monocytogenes.
* Within the species meningococci (Neisseria meningitidis), 13 different serogroups are known (A, B, C, D, 29E, H, I, K, L, W-135, X, Y, and Z). Usually, only serogroups A (mainly in the African “meningitis belt”), B, C, W-135, Y and rarely X (also mainly in Africa) are detected in patients. In Germany, serogroup B is most frequently detected in meningococcal infections (69 %), followed by serogroup C (14 %) and Y (6 %). In about 50% of patients with meningococcal infection, the disease progresses as purulent meningitis. In about 25%, a septic course of disease develops, and another quarter show mixed forms of sepsis and meningitis (see under “Meningococcal sepsis“). The pathogen is transmitted (infection route) via droplets that are produced when coughing and sneezing and are 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). In the case of infection with Listeria monocytogenes, the bacterial source may also be found in raw meat or contaminated dairy products. Transmission of the pathogen can also be hematogenous (via the blood), such as in pneumococcal pneumonia, or direct, such as in open traumatic brain injury (TBI). The incubation period (time from infection to onset of disease) is usually three to four days, and 2-10 days for meningococcal meningitis. Peak incidence: meningococcal disease affects persons under 20 years of age in up to 80% of cases. The incidence (frequency of new cases) is approximately 1-10 cases per 100,000 inhabitants per year (in Germany). Course and prognosis: Bacterial meningitis is a life-threatening septic emergency, the prognosis of which can only be influenced by a rapid start of adequate therapy in the acute phase.The lethality (mortality related to the total number of people suffering from the disease) of meningococcal disease averages 10%, that of pneumococcal meningitis about 15-20% and that of Listeria meningitis up to 50%. The average lethality of the other forms of bacterial meningitis is 10-30%.In about 25% of patients, tuberculous meningitis is lethal in about 25% of HIV-negative patients, and in 67% of cases of HIV co-infection (double infection). Vaccination: A vaccination against Haemophilus influenzae type b (Hib vaccination) is available and is recommended by the STIKO for infants (from the 2nd month of life) and small children.A vaccination against meningococci (serogroups A, B, C) is available. A vaccination against pneumococci is available and recommended by the “Permanent Vaccination Commission” (STIKO) for all children (from the 2nd month of life) and people over 60 years. In Germany, the disease is notifiable according to the Infection Protection Act (IfSG). Notification must be made by name if laboratory evidence is found in blood/liquor. In the case of meningococcal infection, notification must be made by name in the case of suspicion, illness, and death and in the case of laboratory evidence of Haemophilus influenzae.
