export_cns bacteria ii

Question 1

Strep. agalactiae features

Answer 1

Gram-positive cocci in chains
Catalase negative

Beta-hemolytic

Serologically group B

Positive cAMP test

Resists bacitracin

Question 2

GBS colonization

Answer 2

Lower GI and GU tract
Vaginal colonization may occur as well

Maternal intrapartum GBS colonization is a major risk factor

Question 3

GBS virulence factors

Answer 3

Polysaccharide capsule

Question 4

When does early-onset GBS occur?

Answer 4

First week of life

Question 5

Symptoms of early-onset GBS disease

Answer 5

Bacteremia
Pneumonia

Meningitis

Survivors may suffer from permanent neurological sequelae

Question 6

When does late-onset GBS occur?

Answer 6

1-3 weeks

Question 7

Symptoms of late-onset GBS disease

Answer 7

Similar to early-onset
Survival rate is higher

Meningitis is more common

Neurological complications more common

Question 8

Diagnose GBS infection

Answer 8

Recognize clinical signs
ID organism

Serology

Question 9

GBS treatment

Answer 9

Penicillin

Question 10

Prevention of GBS disease

Answer 10

Universal screening of women between 35-36 week’s gestation

Penicillin given about 4 hours prior to delivery

Question 11

Hemophilus influenzae type B features

Answer 11

Gram-negative rod
Fastidious (requires hemin and NAD)

Chocolate agar

6 serotypes (a through f)

Question 12

Which hemophilus influenzae produces meningitis most commonly?

Answer 12

Type b, PRP capsule

Question 13

Hib meningitis symptoms

Answer 13

Fever, stiff neck, headache

~25% of survivors experience neurological sequelae

Question 14

Hib diagnosis

Answer 14

Gram-stain

Latex agglutination test

Question 15

Hib meningitis treatment

Answer 15

Penicillin

Question 16

Hib meningitis prevention

Answer 16

Conjugated vaccine
Anti-PRP Abs

Begin at 2 months of age

Question 17

Clostridium tetani features

Answer 17

Gram-positive rod
Anaerobic

Spore forming

Produce neurotoxin (tetanospasmin)

Question 18

C. tetani transmission

Answer 18

Spores enter via wound contamination or traumatic inoculation
Umbilical stump can be contaminated, resulting in neonatal tetanus

Question 19

C. tetani lifecycle

Answer 19

Spores germinate in anaerobic conditions
Tetanoplasmin produced by vegetative cells

Toxin enters the blood stream, then the nervous system

Question 20

Tetanoplasmin features and toxicity

Answer 20

AB toxin
Binds to motor neurons

Internalized and transported to spinal cord

Inactivates the release of inhibitory neurotransmitters

Causes a spastic paralysis

Question 21

C. tetani treatment

Answer 21

Administer Ig (passive)
Vaccinate with tetanus toxoid (active)

Binding is irreversible; symptoms resolve as new axonal termini are generated

Question 22

C. tetani prevention

Answer 22

Vaccine - DTaP

Begin at 2 months, boosters every 10 years

Question 23

Clostridium botulinum features

Answer 23

Gram-positive rod
Anaerobic

Spore formation

Produce neurotoxin - botulinum toxin

Question 24

C. botulinum intoxication

Answer 24

Ingestion of preformed toxin

Absorbed from gut into blood stream

Question 25

C. botulinum toxin features

Answer 25

AB toxins
Binds to and enters motor neurons

Blocks the release of Ach

Results in flaccid paralysis

Question 26

Listeria monocytogenes features

Answer 26

Gram-positive rod

Motile

Question 27

L. monocytogenes CNS disease

Answer 27

Can cause meningitis

Pregnant women can be infected, resulting in stillbirth, premature delivery, etc.

Question 28

Mycobacterium tuberculosis CNS disease

Answer 28

Can cause meningitis, brain abscess

Disease develops slowly

Question 29

S. aureus CNS infection

Answer 29

Meningitis (following bacteremia)

Brain abscesses - trauma/surgery