Brainscape's Knowledge GenomeTM

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


See full index

Microbiology - Gram Positive > Streptococci > Flashcards

Streptococci Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is the histology under microscope?

A

Gram positive cocci in chains

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

How to categorise the different Streptococci?

A
  1. Haemolysis
    - alpha -> optochin sensitive/resistant
    - beta -> Lancefield group A-G
    - none
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How to classify Enterococci?

A

Gram positive cocci in chains, catalase negative, alpha/beta/non haemolytic, Lancefield group D

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

Example of Group A BHS

A

Streptococcus pyogenes

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

Virulence factors of S.pyogenes

A
  1. M proteins
  2. Erythrogenic toxins
  3. Streptolysins O - form pores which cause cell death and tissue damage
  4. Hyaluronidase - enzyme digest hyaluronic acid
  5. Streptococcus pyogenes exotoxins - antigens trigger polyclonal T-cell activation and cytokine storm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the two types of diseases does S.pyogenes cause?

A
  1. Suppurative (pus forming)
  2. Non-suppurative (post infectious sequelae)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What suppurative infections does S.pyogenes cause?

A

Pharyngitis (sore throat)
- Tonsillitis, quinsy (peritonsillar abscess)
Pneumonia (typical post influenza as super added bacterial infections lead to high death rates in influenza)
SSTI
- Erysipelas, cellulitis
- Severe infection, sepsis/shock/organ failure
- Necrotising fasciitis
Toxic shock syndrome
Scarlet fever (circulating exotoxin usually from pharyngitis)
- Rash
- Pharyngitis
- Strawberry tongue

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

How to treat S.pyogenes necrotising fasciitis?

A

Penicillin + Clindamycin, debridement of wound, IVIG

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

What causes scarlet fever in S.pyogenes?

A

Streptococcal pyogenic exotoxins - erythrogenic toxins

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

What bacteria causes impetigo? How does it spread?

A

Streptococcus pyogenes, Staphylococcus aureus
Spreads easily via close contacts (outbreaks in contact sports like rugby)

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

How to treat S.pyogenes toxic shock syndrome?

A
  • IVIG to mop up toxin
  • Clindamycin to reduce toxin production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does S.pyogenes acute rheumatic fever lead to?

A

Rheumatic heart disease
- damaged heart valves which predispose to infectious endocarditis

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

How to diagnose S.pyogenes acute rheumatic fever?

A

Revised Jones Criteria

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

What antibiotics to prevent S.pyogenes acute rheumatic fever?

A

Oral penicillin/cephalosporins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the Revised Jones Criteria?

A

J: joints polyarthritis
O: carditis
N: subcutaneous nodules
E: erythema marginatum (rash)
S: Sydenham’s chorea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How to diagnose S.pyogenes?

A
  • Culture and gram stain
  • Serology: anti-streptolysin O titres
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How to treat S.pyogenes?

A

Penicillins, cephlasporins, macrolides for penicillin-allergic, vancomycin

Necrotising fasciitis: Penicillin + Clindamycin, IVIG, debridement

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

Example of Group B BHS

A

Streptococcus agalactiae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where is S.agalactiae found in normal flora?

A

GIT and vaginal carriage 30% of the time

20
Q

Who is susceptible to S.agalactiae infection?

A
  1. Neonates and parturient mothers
  2. Adults with co-morbidities, diabetes, nosocomial (soft tissue, chronic wounds, bedbound)
21
Q

How to prevent S.agalactiae infections in neonates?

A

Prophylactic pencillin given to mothers before births

22
Q

What does S.agalactiae cause in neonates?

A

Sepsis
Meningitis
Pneumonia

23
Q

How to treat S.agalactiae?

A

Penicillins, cephlasporin, macrolides for penicllin-allergic, vancomycin

24
Q

What diseases does Group C and Group G BHS cause?

A
  • Pharyngitis
  • SSTI

Toxin and post-streptococcal complications are rare

25
Q

Example of Group D BHS

A

Streptococcus bovis

26
Q

What diseases does S.bovis cause?

A
  1. Endocarditis
  2. Associated with bowel cancer
  3. Hepatobiliary
27
Q

Where is S.bovis found?

A

GIT

28
Q

How to treat S.bovis?

A

Penicillin, cephlasporin, macrolides for pencillin-allergic, vancomycin

29
Q

What diseases does Enterococcus cause?

A
  1. Endocarditis
  2. UTI
  3. Biliary infection
30
Q

What kind of infection does Enterococcus cause?

A

Nosocomial

31
Q

What antibiotic is Enterococcus resistant to?

A

Vancomycin
Cephlasporin
Amoxicillin

32
Q

How to treat Enterococcus?

A
  1. Linezolid, tigecycline
  2. Endocarditis: vancomycin + gentamicin
  3. UTI: ampicillin + gentamicin
33
Q

What are the 2 AHS?

A

Streptococcus pneumoniae
Streptococcus Viridans

34
Q

How does S.pneumoniae grow on and as?

A

Grow on blood agar as draughtsman colonies

35
Q

S.pneumoniae is optochin ___

A

sensitive

36
Q

What diseases does S.pneumoniae cause?

A

INVASIVE: Pneumonia, meningitis, septicaemia, endocarditis
NON_INVASIVE: URTI, sinusitis, otitis, conjunctivitis

37
Q

What are the risk factors for S.pneumoniae?

A

Age, crowding, alcohol, capsule types, asplenic (functional - sickle cell or splenectomy)

38
Q

Histology of S.pneumoniae

A

Gram positive cocci in pairs and chains

39
Q

What kind of pneumonia does S.pneumoniae cause?

A

Lobar pneumonia
Bronchopneumonia
(with rust-coloured sputum)

40
Q

How many capsule types does S.pneumoniae have?

A

> 90 antigenically distinct capsule types due to differences in capsular polysaccharides

41
Q

What are the 2 types of Pneumococcal vaccines?

A
  1. PPSV 23 (penumococcal polysaccharide)
    - poor in very young, given to >65y/o
    - T-cell independent response (IgM)
  2. PCV (conjugate vaccines)
    - Polysaccharide conjugated to a carrier protein
    - Elicits T-cell dependent response with memory (IgG)
    - given to babies
42
Q

Treatment for S.pneumoniae

A

Meningitis: Empirical vancomycin
Respiratory quinolones, cephlasporins, macrolides for penicillin-allergic, vancomycin, penicillins

43
Q

How to diagnose S.pneumoniae?

A
  • Sputum gram stain and culture
  • Blood gram stain and culture
  • Urine antigen detection
44
Q

What does S.viridans group commonly cause?

A

Endocarditis affecting heart valves with prior damage

45
Q

Treatment for S.viridans

A

Penicillin, cephlasporins, macrolides for penicillin-allergic, vancomycin

Microbiology - Gram Positive (9 decks)

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