Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NMSK-B II > Microbiology 2.4 > Flashcards

Microbiology 2.4 Flashcards

1
Q

How do pathogens enter the CNS?

A
  • hematogenous (transverse BBB)
  • peripheral nerves
  • olfactory neurons
  • local injury or congenital defect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the two barriers of the CNS?

A
  • blood brain barrier

- blood CNS barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is Meningitis?

A

infection of the meninges after crossing blood-CSF barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is Encephalitis?

A

infection of the cerebral cortex after crossing the BBB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Meningoencephalitis?

A

both meninges and cerebral cortex are infected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Myelitis?

A

infection of the spinal cord, usually by viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a brain abcess?

A

usually from a bacterial or fungal infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is postinfectious encephalitis?

A

usually 2-3 weeks after an infection elsewhere in the body, peripheral immune cells gain access to brain through BBB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many species of bacteria are typically involved in acute bacterial meningitis?

A

one

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do CNS infections occur in terms of spread?

A

From the bloodstream, the bacteria settle in the large venous sinuses in the brain, then penetrate the dura and arachnoid, and infects the CSF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the clinical presentation of acute meningitis in children and adults?

A
  • fever
  • headache
  • nuchal rigidity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are bacteria-specific manifestations of Streptococcus pneumoniae?

A
  • CSF nasal discharge

- Pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are bacteria-specific manifestation of Neisseria meningitidis?

A
  • Non-blanching petechiae or purpura

- Endotoxic shock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the clinical presentation of acute meningitis in infants and neonates?

A
  • fever
  • lethargy
  • irritability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Neisseria meningitidis

A
  • Small, gram-negative diplococci
  • Aka, meningococcus
  • Facultative intracellular pathogen
  • Strictly a human pathogen
  • catalase +
  • oxidase +
  • ferments glucose, maltose
  • capsule*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the most important disease-producing serogroups of Neisseria meningitidis?

A 
A
C
B [not covered by vaccine]
W-135
Y
**from capsule**
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the most common disease caused by N. meningitidis?

A

acute purulent meningitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the main virulence factors of N. meningitidis?

A
  • polysaccharide capsule
  • IgA protease
  • pili and OMPs
  • LOS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is N. meningitidis transmitted?

A
  • large droplet
  • oral secretions
  • respiratory droplets
20
Q

What is the risk group for N. meningitidis?

A
  • infants
  • adolescents
  • college students
  • military recruits
21
Q

How is N. meningitidis infection treated?

A
  • cephalosporin

- treat those close to them once bug is confirmed

22
Q

What are the two kinds of vaccines available in the U.S. for meningococcals?

A
  • Meningococcal polysaccharide vaccine
  • *no memory response
  • Meningococcal conjugate vaccine (better)
  • *memory response
23
Q

Streptococcus pneumoniae

A
  • Gram-positive coccus
  • Usually diplococci or short chains
  • Facultative anaerobic
  • Encapsulated
  • catalase -
  • alpha-hemolytic (green)
  • Optochin-sensitive**
  • bile soluble (cells are lysed)*
  • capsule*
24
Q

What is the epidemiology of S. pneumoniae?

A

more common during winter and in early spring

25
Q

How is S. pneumoniae transmitted?

A
  • usually autoinoculation

- not usually person-to-person [do not need post-antibiotics for family]

26
Q

What are the main virulence factors of S. pneumoniae?

A
  • polysaccharide capsule
  • IgA protease
  • pneumolysin***
27
Q

What is pneymolysin?

A

A cholesterol-dependent cytolysin that creates pores in cholesterol-containing membranes, thus causing host cell lysis by S. pneymoniae

28
Q

How is a pneumococcal meningitis diagnosis made?

A
  • CSF isolation

- latex agglutination test

29
Q

How is pneumococcal meningitis treated?

A

-vancomycin + ceftiazone

penicillin resistant

30
Q

Streptococcus agalactiae

A
  • Spherical, Gram-positive cocci in chains
  • Only species with group B Lancefield antigen = Group B streptococcus (GBS)
  • Bovine GBS strains can cause mastitis in dairy cows, so “agalactiae” meaning “no milk”
  • catalase -
  • Beta hemolytic
  • bacitracin-resistance
  • CAMP +
  • bippurate test + (purple)
31
Q

Where does Streptococcus agalactiae colonize?

A
  • lower Gi

- GU

32
Q

What is the risk population for Streptococcus agalactiae infection?

A
  • elderly
  • dabetic
  • pregnant women
  • babies
33
Q

What are the risk factors for early onset neonatal GBS disease?

A
  • Maternal colonization of GBS
  • Prolonged rupture of membranes
  • Preterm delivery
  • Intrapartum fever
34
Q

What are the risk factors for late onset neonatal GBS disease?

A
  • From an exogenous source (mother, other neonate, nurse)

- Prematurity

35
Q

What are the virulence factors of S. agalactiae?

A
  • polysaccharide capsule

- pili

36
Q

How is GBS screened for?

A

Pregnant women should undergo vaginal-rectal screening for GBS colonization at 35-37 weeks gestation via culture based testing

37
Q

Listeria monocytogenes

A
  • Short, Gram-positive rods
  • Alone, in pairs or short chains
  • Non-spore forming
  • No capsule!
  • Can’t use morphology alone for diagnosis
  • weak beta-hemolytic
  • catalase +
  • CAMP +
38
Q

How is Listeria monocytogenes distinguished from other Listeria species?

A

sugar fermentation

39
Q

What is tumbling motility?

A

motility in broth on a slide at RT of Listeria monocytogenes

40
Q

Where does Listeria monocytogenes culture?

A
  • soil

- decayaing vegetable matter

41
Q

What are common food sources for Listeria?

A 
"foods in the fridge"
-deli meat
hot dogs
-soft cheeses
-unpasturized milk
-smoked seafood
-meat spread and pate
-melon
-cabbage
42
Q

What are the virulence factors of Listeria monocytogenes?

A
  • actin comets/tails (motility)
  • *avoids immune system
  • facultative intracellular
  • internalin
  • LLO
  • ActA
43
Q

What is the risk groups of listeriosis?

A
  • pregnant women
  • babies
  • immunodeficient
  • elderly
  • *most common in summer
44
Q

How is listeriosis diagnosed?

A
  • culture organism

- “tumbling motility” from CSF

45
Q

What is the treatment for listeriosis?

A

pregnant women: ampicillin

neonates and severe cases: gentamicin

NMSK-B II (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions