Bacterial Infections of CNS Flashcards
Which menigeal layers become inflamed during bacterial infection?
pia mater and the arachnoid
List the primary pathogens of bacterial meningitis (4):
- Group B Streptococcus
- Streptococcus pneumoniae
- Neisseria meningitidis
- Haemophilus influenza
List the occasional pathogens of bacterial meningitis (7):
- Listeria monocytogenes (> 50 years of age)
- Escherichia coli and other Enterobacteriaceae
- Staphylococcus aureus
- Nocardia
- Mycobacterium tuberculosis (AIDS associated)
- Borrelia burgdorferi, Leptospira, Treponema pallidum
- Brucella
- Brain damage during meningitis is mostly attributable to ….
- Bacteria like Streptococcus pneumoniae cause that leads to tissue damage?
- Problem, early signs of meningitis can resemble the symptoms of:
- What is the key to curing infections?
- Brain damage during meningitis is mostly attributable to the side effects of the host’s own inflammatory response
- Bacteria like Streptococcus pneumoniae activate leucocytes
- release proteolytic enzymes and reactive oxygen species
-
Problem, early signs of meningitis can resemble the symptoms of:
- influenza
- altered mental status (confusion)
- Key: rapid diagnosis
Bacteria that cause CNS infection in:
Premature babies and newborns up to 3 months old
-
group B streptococci
- inhabit the vagina
- mainly a cause during the first week of life
- Escherichia coli
- normally inhabit the digestive tract
- carry the K1 antigen
- Listeria monocytogenes
Bacteria that cause CNS infection in:
Older Children
- Streptococcus pneumoniae
- Neisseria meningitidis
- Haemophilus influenzae type B
- in countries that do not vaccinate
Bacteria that cause CNS infection in:
Adults
-
Streptococcus pneumoniae and Neisseria meningitidis together
- 80% of bacterial meningitis cases
- Listeria monocytogenesis a risk in the elderly > 50 years
Which of the primary bacterial pathogens of the CNS does **not **have a vaccine?
Group B Streptococcus
(agalactiae)
- Most capsules are composed of ___________
- __________ antibodies prevent host cell phagocytosis
- Most capsules are composed of polysaccharides
- Anti-capsule antibodies prevent host cell phagocytosis
H. influenzae
- How many serotypes are there?
- Which one causes virtually all invasive infections?
- What plays a role in protection from infection?
- 6 serovars
- Virtually all invasive infections are due to type b H. influenzae (Hib)
- Antibodies to this polyribosylribose phosphate capsular antigen play a role in protection from infection by Hib
Describe the immunity to Hib:
- Good relationship between age & susceptibility
- Children < 3 month, maternal Abs are protective
- Most invasive disease occurs between 3 month and 3 years of age
- Children under 3 years of age show a humoral immunodeficiency to Hib
- Children older than 3 years of age develop bactericidal
- Ig to Hib (vaccination/non-clinical exposure)
What is the correlation between Hib meningitis and antibody titers?
Good correlation – incidence meningitis and antibody titers to the Hib capsule
- i.e. Incidence ↓ as antibody titer ↑
What was the problem with the 1st generation Hib vaccine?
Purified capsular polysaccharide
-
Polysaccharides are:
- poor immunogens
- stimulate T-independent Ab
- poor immunologic memory
What is the composition of the 2nd generation Hib vaccines?
PRP protein conjugates
Polysaccharide-conjugate vaccines stimulate a ….
T-cell dependent antibody response and a memory response