Microbiology of CNS Infections: Part 1

Question 1

CSF Production and composition

Answer 1

Choroid plexus

Serum plasma…great growth medium and immunoprivileged

Question 2

Acute meningitis presentation and differentiation

Answer 2

Fever, persistent headache, photophobia and neck stiffness

Bacterial - very sick and increase in protein and oncotic pressure with decrease in glucose

Viral - ill, but not awful (aseptic)

Question 3

Actue viral meningitis cause…type of virus, spread, and life…what causes damage

Answer 3

Most common cause of meningitis

Mostly enteroviruses (Naked ssRNA+, stable at low pH, fecal oral spread and replicate in GI and enter BS)

Host reaction to viral antigens causes damage

Question 4

What can differentiate meningitis from encephalitis

Answer 4

Meningitis has no focal neurologic findings

Question 5

Actue bacterial meningitis

Answer 5

Crosses BBB…leads to edema and increased inter cranial pressure…will get WBC infiltration

Will show papilledema…don’t do LP because brain will be sucked down and cause problems

Question 6

Ages and acute bacterial meningitis (stains)

Answer 6

0-6 - GBS+, Listeria+, E coli-
6-6 - S penumo+, Neisseria-, H influenzae-
6-60 - S pneumo+, Neisseria-
Over 60 - S penumo+, Listeria+, E coli-

Question 7

Gram + vs. Neg

Answer 7

+ has lipoteichoic acids and thick pepitoglycan

- has LPS with protein A

Question 8

Neonatal meningitis most common cause

Answer 8

Streptococcus agalactae (+ rod) Catalase -, beta hemolytic

Non specific symptoms

Mothers screened for GBS

Acquired during birth bc found in vaginocervical tract and GI tract

Question 9

Listeria monocytogenes

Answer 9

+ rod

In soft cheeses and grows at low temps

Question 10

E coli

Answer 10

Gram - rod
Fecal oral spread
Lactose fermenting (pink on MacConkey Plate_
K1 capsule allows survival in lysosomes

Question 11

Neisseria meningitides

Answer 11

Gram - diplococci

Inhalation

Pilli, capsule, IgA protease

Bacteria enter blood and can cause meningococcemia and Waterson Fridericsen syndrome

LOS endotoxin blebs off and is released upon cell death (causes vasculitis and petechiae)

Grow on chocolate agar

Question 12

H influenza

Answer 12

Gram - coccobacillus 
Chocolate agar because needs heme and NAD 
Resp droplets spread
Type B causes most 
Hib vaccine

Question 13

S pnueymo

Answer 13

Polysaccharide capsule inhibits C3b and antiphaogcytic
Pilli
IgA protease

Question 14

S penumo vaccines

Answer 14

Polysacch - Over 2 y/o

Conjugate - under 2 y/o

Question 15

Encephalitis

Answer 15

Inflammation of brain parenchyma
MCC arboviral
Sensory or motor deficitis
Diagnose with IgM serology or PCR

Question 16

WNV

Answer 16

ssRNA negative
Can be mild or severe depending on patient

Must contain RDRP and genomic material itself is not infectious