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MICROM 442 > Exam 1 Lecture 9 > Flashcards

Exam 1 Lecture 9 Flashcards

1
Q

True or False: Streptococcus is a genus of gram-negative coccus. Most tend to be in chains. Some tend to be in pairs (end to end diplocci), bullet-shaped, lancet-shaped

A

False. Streptococcus is a genus of GRAM-POSITIVE bacteria

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2
Q

Do streptococci have catalase?

A

No

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3
Q

Most streptococci are ________ _______, meaning that they can grow anaerobically and aerobically

A

facultative anaerobes

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4
Q

True or False: Streptococci do not use oxygen in their metabolism

A

True

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5
Q

Name 2 types of streptococci that are α-hemolytic

A
  1. Viridans streptococci

2. Streptococcus pneumoniae

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6
Q

How can we tell if bacteria is α-hemolytic on a blood agar plate?

A

It will form greenish discoloration where the colony grows

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7
Q

Name 2 types of streptococci that are β-hemolytic

A
  1. Group A streptococcus

2. Streptococcus pyogenes

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8
Q

How can we tell if bacteria is β-hemolytic on a blood agar plate?

A

The bacteria will completely lyse the red blood cells around or under the colony. The area appears light yellow or clear

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9
Q

Name an example of streptococci that do not fit in the category of α-hemolysis or β-hemolysis

A

Streptococcus bovis

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10
Q

S. pneumoniae can cause a range of diseases. List what those diseases are (5 things)

A
  1. ear infection
  2. sinusitis
  3. pneumonia
  4. blood infections (bacteremia)
  5. meningitis
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11
Q

True or False: Cracking upon auscultation is commonly seen in patients with pneumococcal pneumonia

A

True

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12
Q

Who are people most at risk for severe symptoms of Pneumococcal disease? (2 things)

A
  1. Smokers

2. People w/ asthma or other respiratory issues

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13
Q

What does pneumococcal disease often follow?

A

Respiratory infections like influenza

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14
Q

__________ is the most common cause of bacteremia, meningitis, and middle ear infections in children.

A

Pneumococcus

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15
Q

What is bacteremia and what groups of people is it most dangerous for?

A
  • Bacteremia is a type of invasive pneumococcal disease that infects the bloodstream.
  • Children under 5 and the elderly
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16
Q

Why can bacteremia be dangerous?

A

It can lead to sepsis and possibly septic shock, which can lead to death

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17
Q

How is transient bacteremia different?

A

Bacteria can get in the blood and grow and divide, but in a healthy individual, the immune system is able to overcome it

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18
Q

True or False: Bacteremia is more severe than meningitis

A

False. Meningitis is much more severe.

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19
Q

What is meningitis?

A

Inflammation of the meninges (the protecting lining surrounding the brain & spinal cord)

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20
Q

True or False: S. pneumoniae are Gram-positive cocci that tend to be in pairs

A

True

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21
Q

Over time, the initial round + glistening S. pneumoniae colonies flatten. This is due to a compound known as _____.

A

autolysin

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22
Q

How many diff serotypes does S. pneumoniae have?

A

98

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23
Q

Name one major virulence factor of S. pneumoniae

A

polysaccharide capsule

24
Q

What leads to the various serotypes of S. pneumoniae?

A

Variations in the capsule composition, which has to do w/ variable expression of glycosyltransferase and other sugar-dependent synthesis genes

25
Q

True or False: S. pneumoniae is not naturally competent for genetic transformation

A

False

26
Q

In 2-3 year olds, 60% can be carriers of S. pneumoniae. Where does S. pneumoniae colonize?

A

The mucosal surfaces lining the nasopharynx

27
Q

Increased production of _____ can lead to increased transmission.

A

mucus

28
Q

How does S. pneumoniae spread? (3 things)

A

Direct contact, respiratory droplets, some evidence for fomite transmission

29
Q

What is the role of the capsule? (3 things)

A
  1. Crucial in colonization by preventing entrapment in mucus
  2. Expression undergoes phase variation between thick and thin capsule
  3. Required for invasion (prevents opsonization, inhibits complement)
30
Q

Name a second major virulence factor

A

Pneumolysin

31
Q

Monomers of pneumolysin bind to _______, then it oligomerizes and forms a _____ that consists of 50 monomers. The formation of the _____ causes cell to lyse and eventually die.

A

cholesterol, pore, pore

32
Q

What is the role of Ply? (4 things)

A
  1. Increases mucus production by inducing inflammation, thus increasing transmission
  2. Damages mucociliary escalator by inhibiting cilia beating
  3. Recruitment of host inflammatory cells
  4. Forms pores in host cells
33
Q

What does Ply specifically form pores in?

A

Alveolar epithelium

34
Q

What is the quickest way to detect the presence of S. pneumoniae?

A

Urine antigen test

35
Q

What does the urine antigen test detect that is common to all serotypes of S. pneumoniae?

A

C polysaccharide antigen

36
Q

True or False: the urine antigen test is more sensitive than culture and Gram stain

A

True

37
Q

What’s a downside to the urine antigen test?

A

No info on antibiotic susceptibility (b/c we don’t know the serotype)

38
Q

What are 2 characteristics used to ID S. pneumoniae in vitro?

A
  1. Optochin-sensitive

2. Bile-solube

39
Q

The colonies of S. pneumoniae dissolve when ______ ______ is added. Thus this indicates that the colony is bile solube.

A

Sodium deoxycholate

40
Q

True or False: There is 1 vaccine currently available for S. pneumoniae

A

False. There are two - PPSV23 and 13vPCV)

41
Q

Which vaccine is recommend for infants AND adults?

A

The conjugate vaccine

42
Q

The polyvalent pneumococcal polysaccharide vaccine contains _______ from the capsule of ___ different serotypes. It is intended for adults over 65, but not children.

A

polysaccharides, 23

43
Q

How many serotypes does the conjugated vaccine cover?

A

13

44
Q

What is the treatment for S. pneumoniae?

A

It depends on the strain. If it’s penS, then use PenG or amoxicillin.
If it’s penR, increase the dose of use cephalosporins, fluoroquinolones.

45
Q

If S. pneumoniae is not confirmed by lab, a ______ may be given. If the patient is resistant, use _______/

A

macrolide

fluoroquinolone

46
Q

Viridans strep. is a gram-positive that comes in ____ and has _____ _____. They are _ hemolytic.

A

pairs, short chains

alpha

47
Q

Where does S. mutans colonize?

A

The oral cavity

48
Q

What does S. mutans contribute to?

A

Cavities

49
Q

S. mutans uses _____ to to produce ________, which allows it to synthesize ________ ___________ by using _______________.

A

sucrose
glucans
extracellular polysaccharides
glucosyltransferases

50
Q

Use of sucrose to produce glucans allows S. mutants to attach better to ______ and ______ _____.

A

enamel

heart valves

51
Q

When may transient bacteremia occur?

A

flossing, teeth brushing, dental procedures

52
Q

True or False: endocarditis is especially a risk when the individual has injured or inflamed heart valves

A

True

53
Q

Where is S. anginosus commonly found?

A

oral cavity, GI

54
Q

What does S. anginosus smell like?

A

butter, butterscotch!

55
Q

What is unique about the pathogenicity of S. anginosus?

A

It tends to lead to abscess formation

MICROM 442 (26 decks)

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