Lesson 1: STREPTOCOCCUS Flashcards

1
Q

Family Streptococcaceae 3 genera

A

Streptococcus
Enterococcus
Lactococcus

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2
Q

Catalase negative

A

Streptoccoci

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3
Q

Media used for Streptococci

A

BAP
CHOC
Todd-Hewitt Broth

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4
Q

Streptococci

Facultative anaerobes and needs ? CO2 for growth

A

5-10%

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5
Q

● Green discoloration

A

Alpha hemolytic

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6
Q

Organisms w A-hemolysis

A

S. pneumoniae
S. viridans

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7
Q

Clear or colorless zone of hemolysis surrounding bacterial colony

A

Beta hemolytic

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8
Q

Organisms w B-hemolysis

A

S. pyogenes
S. agalactiae

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9
Q

Non-hemolytic

A

Gamma hemolytic

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10
Q

Organisms w Gamma hemolysis

A

Enterococcus spp.

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11
Q

Physiologic divisions

A

Pyogenic division
Viridans division
Enterococcus division
Lactic division

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12
Q

Found in Sherman 1937

A

Bergey’s/Academic Classification

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13
Q

PHYSIOLOGIC DIVISION (Streptococci)

  • streptococcal organisms = diseases associated w PUS FORMATION
A

Pyogenic division

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14
Q

PHYSIOLOGIC DIVISION (Streptococci)

Includes beta hemolytic strains

A

Pyogenic division

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15
Q

Lancefield groups

A

A, B, C, E, F, and G

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16
Q

PHYSIOLOGIC DIVISION (Streptococci)

Difference between Viridans and Enterococcus division

A

Viridans - not salt tolerant
Enterococcus - salt tolerant

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17
Q

PHYSIOLOGIC DIVISION (Streptococci)

● Not beta hemolytic
● Not salt tolerant
● Grow at high pH

A

Viridans division

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18
Q

PHYSIOLOGIC DIVISION (Streptococci)

● Salt tolerant
● Grow at high pH

A

Enterococcus division

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19
Q

PHYSIOLOGIC DIVISION (Streptococci)
Enterococcus division

Temp range

A

10C-45C (optimal growth temp)

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20
Q

PHYSIOLOGIC DIVISION (Streptococci)

● Not clinically significant
● Associated with dairy industry

A

Lactic division

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21
Q

Developed Lancefield Grouping

A

Rebecca Lancefield (1933)

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22
Q

Divides the Streptococci into serological groups; Based on antigenic properties of carbohydrate group antigens in their cell wall

A

Lancefield Grouping

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23
Q

Lancefield grouping

Clinically significant; Mostly isolated and associated with human infections

A

A, B, C, D, F, and G

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24
Q

Done to differentiate Streptococci into groups

A

Serological testing

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25
Q

Lancefield group A

A

S. pyogenes

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26
Q

Lancefield group B

A

S. agalactiae

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27
Q

Lancefield group C and G

A

S. dysgalactiae and S. equi

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28
Q

Lancefield group A, C, F, and G

A

S. anginosus

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29
Q

Not a normal flora
Most virulent for humans

A

GROUP A: STREPTOCOCCUS PYOGENES (GAS)

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30
Q

GAS Diseases

A
  • Bacterial Pharyngitis
  • Skin infections
  • Invasive diseases
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31
Q

GAS Complications

A

Rheumatic heart disease
Acute glomerulonephritis

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32
Q

GAS transmission

A
  • person to person contact
  • aerosol droplets
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33
Q

GAS Major Virulence Factors

  • Anti-phagocytic: protects the organism from being phagocytosed
  • Reason for mucoid colonies
A

Hyaluronic acid Capsule

34
Q

GAS Major Virulence Factors

  • Precipitates fibrinogen
  • Clumps platelets and WBCs
  • Inhibits migration of WBCs
A

M protein

35
Q

GAS Major Virulence Factors

Group-specific cell wall antigen

A

Grp. A sugar: rhamnose-N-acetylglucosamine

36
Q

GAS Major Virulence Factors

● Equipped with structures that allow them to act like immune cells
● No antigen-antibody complex

A

IgG and IgA - binding proteins

37
Q

important anaphylotoxin; Part of initiation of inflammatory process

A

C5a

38
Q

GAS Major Virulence Factors

Byproduct of complement cascade

A

C5a protease

39
Q

GAS Major Virulence Factors

Inhibits neutrophil chemotaxis in vitro

A

C5a protease

40
Q

attach to mast cells and basophils → initiate the release of histamine → further inflammatory reaction

A

C5a

41
Q

Allows binding to fibronectin in pharyngeal epithelium

A

F protein

42
Q

binding site for organisms on membranes of host cells

A

Fibronectin

43
Q

Attached to M protein; May allow binding to fibronectin

A

Lipoteichoic acid

44
Q

● Fibrinolysin that lyses blood clots
● Similar function with staphylokinase

A

Streptokinase

45
Q

Degrades host DNA & RNA

A

Streptodornase

46
Q

● Can hydrolyze or break down hyaluronic acid which is part of the connective tissue
● Important in spreading the infection

A

Hyaluronidase

47
Q

Associated with the organism’s ability to destroy WBCs

A

Diphosphopyridine nucleotidase

48
Q

Most potent pyrogenic exotoxin

A

A

49
Q

● Associated with fever and rashes in scarlet fever
● Responsible for the increase in temperature and rashes (especially in Scarlet fever)
● Associated with Streptococcal TSS

A

Pyrogenic exotoxins/ erythrogenic toxins

50
Q

Pyrogenic exotoxins/ erythrogenic toxins

A

A, B, C

51
Q

more fatal TSS

A

Staphylococcal TSS

52
Q

Oxygen labile; Antigenic (Anti-Streptolysin O)
○ Can induce antibody response
○ Can be detected serologically

A

Streptolysin O

53
Q
  • Oxygen stable
  • Toxic to various types of human cells but non-antigenic
  • Do not trigger an immune response
A

Streptolysin S

54
Q

Pyogenic disease

A

Erysipelas
Cellulitis
Impetigo

Streptococcal pharyngitis

55
Q

Erysipelas is also known as

A

St. Anthony’s Fire

56
Q

● Spreading of rashes across the face, legs
● Itchy and hotter compared to other parts of the body
● NO PUS production, but exotoxin A production (increase temperature in the area) & rashes

A

Erysipelas

57
Q

● Inflammation of deep tissues including the skin
● Common in middle-aged individuals

A

CELLULITIS

58
Q
  • Begins as fluid-filled blisters that usually erupts creating weeping lesions
  • Mouth and nose area; Common in children
A

Impetigo

59
Q

● Red, swollen tonsils
● Pus formation

A

STREPTOCOCCAL PHARYNGITIS (STREP THROAT)

60
Q

Strep throat lasts from

A

3-5 days

61
Q

Toxigenic disease

A

Necrotizing Fasciitis
Scarlet Fever
Streptococcal Toxic Shock Syndrome

62
Q

Made streptococcus pyogenes earn the name of “flesh-eating
bacteria”

A

Necrotizing fasciitis

63
Q

Process of removing necrotized skin = infection does not spread

A

Debridement

64
Q

Nectrotizing fasciitis active component

A

Exotoxin A

65
Q

Necrotizing fasciitis: cause the actual tissue damage

A

Macrophage

66
Q

Necrotizing fasciitis: Destruction of tissue occur at a rate of -

A

2 inches per hour

67
Q
  • May occur after streptococcal pharyngitis or other infection; Pyrogenic exotoxin is present
A

Scarlet fever

68
Q

Characteristic sign of scarlet fever

A

Strawberry tongue

69
Q
  • Toxin mediated
  • Hypotension, multi-organ failure, fever, erythema, swelling, tachycardia, acute respiratory distress, renal impairment and shock is observed
A

STREPTOCOCCAL TOXIC SHOCK SYNDROME

70
Q

Proliferation of glomerular tissue that can result in damage to the basement membrane

A

Acute glomerulonephritis

71
Q

Comprises a specific set of renal disease; immunologic mechanism; triggers inflammation

A

Acute glomerulonephritis

72
Q

Cardiac inflammation and scarring; triggered by an autoimmune reaction to infection w GAS

A

Rheumatic heart disease

73
Q

This condition in the acute stage may consist of pancarditis

A

Rheumatic heart disease

74
Q

System disease that occur after an untreated strep throat due to GAS

A

Acute rheumatic fever

75
Q
  • Preceded by skin or respiratory infections
  • Represents a HYPERSENSITIVITY response
  • Immune-mediated
A

Post-Streptococcal Diseases

76
Q

Streptococci culture incubation

A

Incubation for 18-24 hrs. @ 37C with 5-10% CO2 since they are fastidious

77
Q

Streptococcal culture

● white to gray pinpoint colonies, translucent, opalescent.
● Wide zone of B-hemolysis

A

BAP

78
Q

Streptococcal culture

  • is addedto BAP
A

trimethoprim/sulfamethoxazole

79
Q

Most virulent strain in mucoid colonies

A

M protein 49

80
Q

Biochemical test to differentiate Streptococcus from Staphylococcus

A

Catalase test