Bacterial Meningitides Flashcards
(early onset/late onset) neonatal group b strep
major clinical manifestations are bone/joint infections, and bacteremia with concomitant.fulminant meningitis
late onset
Two agars associated with Neisseria meningitidis
Chocolate agar
Thayer-Martin agar
What is the causative agent of meningococcal meningitis
Neisseria meningitidis
What are the two virulence factors of Listeria monocytogenes
- lipopolysaccharide-like surface component
2. Listeriolysin O
3 microbes that most commonly cause community acquired meningitis
s. pneumoniae
h. influenzae
n. meningitidis
(organisms able to colonize the respiratory tract)
neonatal meningitis predisposing factors *neonatal factors:
immature immune system
immature organs
low birth weight
Which meningitis microbe is associated with the presence of petechiae and pink macules with widespread eruption within hours
Neisseria meningitidis
What is the most common cause of bacterial meningitis (NOT NEONATAL!)
Strep pneumoniae
What is the most common cause of transmission of Listeria monocytogenes
food
What does streptococcus agalatiae (group B strep) look like on agar?
gray-white colonies with a narrow zone of b-hemolysis
(early onset/late onset) neonatal group b strep
symptoms develop from 7 days to 3 months of age
late onset
What is the cause of systemic toxicity of CNS infections
exotoxin activity
What is the leading cause of meningitis in cancer and renal transplant patients
listeriosis
What is the most common agent in patients with recurrent meningeal infections
Strep pneumoniae
Neisseria meningitidis
gram (+/-)
shape?
negative
diplococcus
survivors of neonatal meningitis typically have
permanent defects
What was the most common cause of bacterial meningitis before 1986
Haemophilus influenzae
what is another name for group B strep
streptococcus agalatiae
What does Listeria monocytogenes require for growth
reduced oxygen tension for in vitro growth
FACULTATIVE INTRACELLULAR PATHOGEN
Which microbe is associated with a “tumbling” motility in hanging drop preparation
Listeria monocytogenes
streptococcus agalatiae
group B strep
gram (+/-)
shape?
gram +
coccus
What is the prognosis or neonatal meningitis
poor
What kind of cells do Listeria monocytogenes like to grow in?
epithelial cells
macrophages and monocytes
What is the most common cause of neonatal bacterial meningitis
streptococcus agalatiae
group B strep
You do the tumbler test and roll a glass on a rash of your patient and the color DOES change… whatchu got
not Neisseria meningitidis
probably allergies
(early onset/late onset) neonatal group b strep
symptoms develop during first 5 days of life
early onset
Classic triad of symptoms of meningitis
- fever
- headache
- neck stiffness
What is a gram negative organism from the GI tract that can cause neonatal meningitis
E. Coli
higher incidence of meningitis in these populations: (4)
- new borns (up to 8 months)
- elderly
- immunocompromised
- developing countries
What two terrible things can happen from Meningococcemia
DIC
gram negative shock
____% of colonized neonates develop neonatal bacterial meningitis
1-2
You do the tumbler test and roll a glass on a rash of your patient and the color does NOT change… whatchu got
Neisseria meningitidis
How is Listeriolysin O a virulence factor for Listeria monocytogenes
disrupts phagolysosome memebrane
inhibits antigen processing
induces apoptosis
What causes the eventual decrease of blood flow to the brain in meningitis infections?
“leaky” blood vessels allow fluid, WBCs and other immune components to enter the brain
due to BBB becoming partially disrupted
Infections of the CNS 2 broad categories:
- meningitis
2. encephalitis
4 signs and symptoms specific to neonatal bacterial meningitis
- bulging fontanelle
- high pitched cry
- hypotonia
- paradoxic irritability
presumptive lab tests for streptococcus agalatiae (group B strep)
CAMP factor
accentuation of hemolysis due to interaction with staph b-lysin
(early onset/late onset) neonatal group b strep
major clinical manifestations are bacteremia, pneumonia, and meningitis
early onset
What are the two main manifestations of Listeriosis
sepsis
meningitis
What are the main causes of hospital acquired meningitis
iatrogenic procedures
altered immune status
What is the only reservoir of Neisseria meningitidis
humans
(early onset/late onset) neonatal group b strep
maternal obstetric complications are common
early onset
How is lipopolysaccharide-like surface component a virulence factor for Listeria monocytogenes
antiphagocytic
complement-dependent hemolytic antibodies
Which meningitis microbe is associated with growing on a very selective agar made of Mueller Hinton supplemented with sheep RBCs and antibiotics
(vanco, colistin, nystatin, and bactrim)
Neisseria meningitidis
Which microbe is associated with the tumbler test
Neisseria meningitidis
What are the four virulence factors of streptococcus agalatiae (group B strep)
- capsular polysaccharide
- hyaluronidase
- collagenase
- hemolysin
Encephalitis is inflammation in the:
parenchyma
neonatal meningitis predisposing factors *maternal factors
premature rupture of membrane
urogenital infection during late term
intrauterine infection during early term
invasion of the uterine space
definitive diagnosis for streptococcus agalatiae (group B strep)
isolation from blood, CSF
Meningitis is inflammation resulting from an infection in the:
subarachnoid space
what are the 5 most important serogroups of Neisseria meningitidis?
Which ones are in the quadrivalent vaccine?
A, B, C, Y, W35
all but B
What are the 3 pathways for gaining access to the CNS
- invasion of the bloodstream and seeding of the CNS
- Retrograde neuronal pathway
- direct contiguous spread
What is a classic feature of listeriosis in adults?
brain stem encephalitis
What is the difference between acute and chronic meningitis
acute = symptom onset of hours to several days chronic = symptom progression for more than 4 weeks
(early onset/late onset) neonatal group b strep
maternal obstetric complications are uncommon
late onset
Listeria monocytogenes
gram (+/-)
shape?
motile?
gram positive
coccobacillus
motile
What is the only microbe associated with summer seasonality for meningitis
Listeria monocytogenes
What is the most common cause of bacterial meningitis now (after 1986)
strep pneumo
Why do outbreaks of Neisseria meningitidis happen in college dorms and military barracks
because it requires close quarters for transmission
What is the reason incidence of meningitis has declined significantly
- availability of vaccines
2. universal screening of pregnant women for Group B strep
What is the negative result of the release of inflammatory cytokines once the bacteria crosses the blood-brain barrier
WBC diapedesis into CSF —>
increased permeability of blood-brain barrier —>
edema, intracranial pressure, altered blood flow
Predominant agents of NEONATAL meningitis
streptococcus agalactiae
escherichia coli
listeria monocytogenes
What is the most common pathway of an infection gaining access to the CNS
invasion of the bloodstream and seeding of the CNS
What blood studies are useful in the diagnosis of meningitis
CBC
Serum electrolytes
Liver profile
SERUM GLUCOSE compared to CSF
What are the main microbes associated with hospital acquired meningitis
gram negative rods
s. aureus
“other strep and staph”
Which meningitis microbe is associated with being able to live at very low temps in the fridge or freezer
Listeria monocytogenes
