Bacterial Infection of the CNS (1)

Question 1

Are all neisseria pathogenic?

Answer 1

No, to be pathogenic they must be encapsulated

Question 2

Describe the bacteriology of meningococcus (N. meningitidis)?

Answer 2

Gram(-) diplococci
Aerobic/facultative
Human-restricted
Oxidase-positive
Catalase-positive
Ferments maltose and glucose

Question 3

How is meningococcus transmitted?

Answer 3

Airborne droplets

Question 4

Name the virulence factors of meningococcus?

Answer 4

IgA protease, LOS, and polysaccharise capsule

Question 5

Where does meningococcus normally colonize?

Answer 5

the Nasopharynx (only reservoir)

Question 6

What can predispose a patient to a meningococcal infection that spreads beyond the respiratory tract?

Answer 6

Deficiency in complement C6-C9

Question 7

What media needs to be used to culture meningiococcus?

Answer 7

Thayer Martin/ Chocolate agar plates

Question 8

What will an exam show with an meningococcal infection?

Answer 8

Septic arthritis and meningitis (adults have typical symptoms and pediatric patients have irritability, convusions, fever, abd pain)

Question 9

What are the symptoms of meningococcemia?

What is Waterhouse-Friderichen Syndrome?

Answer 9

Fever and hourly spreading rash

W-F syndrome: high fever, shock, widespread purpura, DIC, thrombocytomenia, destruction of adrenal glands

Question 10

Describe the host defense to menigococcus?

Answer 10

Host defends with IgG-enhanced complement and PMNs

Question 11

How are menigococcal septic arthritis, meningitis and menigococcemia diagnosed in the lab?

Answer 11

spetic arthritis: Gram stain, culture on chocolate agar

Meningitis: gram stain culture om chocolate agar, CSF smear for Gram (-) cocci

Meningococcemia: Gram stain culture on chocolate agar, blood tests for DIC

PCR tests are also available

Question 12

Treatment for menincococcal infections?

Answer 12

Penicillin G/ ceftriaxone/ fefixime

NO STEROIDS

Question 13

Is there a vaccine for meningococcal infections?

Answer 13

Yes, but it doesn’t prevent asymptomatic carriage.

Question 14

What is the bacteriology of GBS?

Answer 14

Gram (+) cocci
Beta hemoytic
Encapsulated
Polysaccharide toxin virulence

Question 15

Where is GBS usually found?

Answer 15

Normal flora in vagina, GI or respiratory tract

Question 16

Who does GBS cause disease in?

Answer 16

Neonates ad elderly with pre-existing major health conditions

Question 17

What disease does GBS cause in neonates?

Answer 17

Early disease: Pneumonia w/ bacteremia (presents 1-7 days postpartum)

Late disease: Bacteremia w/ meningitis (presents 1-12 wks postpartum)

Question 18

What serotype of GBS causes neonatal infections typically?

Answer 18

Serotype 13

Question 19

What three pre-existing major health conditions cause GBS in the elderly?

Answer 19

Diabetes, malignancy, CHF

Question 20

How does an infant w/ GBS present?

Answer 20

Penumonia (early) or meningitis (late)

Question 21

How does an elderly patient w/ GPS present?

Answer 21

Cellulitis, meningitis, abscess, endocarditis

Question 22

What are the ways to diagnose GBS infections?

Answer 22

Gram stain/ culture or appropriate sample

CT/ MRI for abscesses

Echocardiogram for enocarditis

Antigen tests

CAMP test

Hippurase Test

Question 23

How is GBS treated?

Answer 23

IV penicillin, amoxicillin, vancomycin

Surgery might be needed

Question 24

How is GBS prevented?

Answer 24

Test term-pregnant patients and if positive treat intrapartum with IV penicillin or amoxicillin or clindamycin (if resistant)

Question 25

What pathogen causes pneuomococcus?

Answer 25

Strep pneumoniae

Question 26

Bacteriology of pneumococcus?

Answer 26

Gram(+)
Catalase(-)
Diplococci , form chains in culture
Pathogenic strains are encapsulated

Question 27

Pneumococcus is the most common cause of…

Answer 27

Community-acquired pneumonia, bacterial meningitis, bacteremia, and otitis media

Question 28

Where do individuals carry pneumococcus?

Answer 28

Upper respiratory tract

Question 29

What two ways does pneumococcus escape its normal colonized area of the upper respiratory tract?

Answer 29

Direct extension and Hematogenous spread

Question 30

What can pneumococcus infect by direct extension?

Answer 30

Sinuses, bronchi and eustachian tubes

Question 31

What can pneumococcus infect by hematogenous spread?

Answer 31

blood, peritoneum, CSF, joint fluid

Question 32

What diseases does non-invasive (direct extension) pneumococcus cause?

Answer 32

Sinusitis, Mild/ severe pneumonia, otitis media

Question 33

What diseases are caused by invasive (hematologenous spread) pneumococcus?

Answer 33

Meningitis, septic arthritis, endocarditis

** there is a strong inflammatory response

Question 34

What radiological finding is typical of severe pneumoccocal pneumonia?

Answer 34

Lobar consolidation

Question 35

Spinal tap findings typical meningitis?

Answer 35

1- Elevated opening pressure

2- Elevated WBC count and neutrophil level

3- Elevated protein

4- Decreased glucose

5- Highly elevated lactic acid

6- Gram stain and culture are positive unless antibiotic treatment began >4hrs prior to tap

Question 36

How is diagnosis of invasive pneumococcus made?

Answer 36

Gram stain and culture of appropriate samples Urine antigen testing is also possible

Question 37

Treatment for noninvasive and invasive pneumococcus?

Answer 37

Noninvasive: amoxicillin/ cephalosporin and if severe admit and treat with vancomycin

Invasive: Initial antibiotic is vancomycin and add rifampin, meropenem or chloramphenicol if there is resistance

Question 38

What are the two important factors regarding pneumococcal antibiotic testing?

Answer 38

1- It is confirred by muttions changing the bacterial cell wall sites to which the antibiotics bind so the affinitiy is lowered

2- Resistance is carried on transposons that include multiple resistance genes (typically)

Question 39

Can steriods be used in pneumococcal meningitis?

Answer 39

Yes, but sparingly

Question 40

Can pneumococcal infections be prevented?

Answer 40

Yes…2 vaccines (Prevnar7 and Prevnar13)