Streptococcus Flashcards

1
Q

Characterized by greenish hemolysis around the colony

A

ALPHA (α)

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2
Q

Due to incomplete/ partial destruction of red blood cells

A

ALPHA (α)

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3
Q

Example of bacteria that has alpha hemolysis

A

Viridans streptococci and Streptococcus pneumoniae

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4
Q

Characterized by clear, colorless zone of hemolysis

A

BETA (β)

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5
Q

Due to complete destruction of red blood cells

A

BETA (β)

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6
Q

Example of bacteria that has beta hemolysis

A

Streptococcus pyogenes and
Streptococcus agalactiae

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7
Q

Non – hemolytic on blood agar

A

GAMMA (γ)

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8
Q

Example of bacteria that has gamma hemolysis

A

Enterococcus faecalis

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9
Q

LANCEFIELD CLASSIFICATION is Based on the ________ antigen found in the cell wall

A

C – carbohydrate

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10
Q

Bacteria’s that do not have carbohydrate cell wall antigen

A

Streptococcus pneumoniae & Viridans streptococci

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11
Q

LANCEFIELD CLASSIFICATION

A

A

Streptococcus pyogenes

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12
Q

LANCEFIELD CLASSIFICATION

B

A

Streptococcus agalactiae

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13
Q

LANCEFIELD CLASSIFICATION

C

A

Streptococcus equisimilis,
Streptococcus zooepidemicus,
Streptococcus equi

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14
Q

LANCEFIELD CLASSIFICATION

D (enterococci)

A

Enterococcus faecalis,
Enterococcus facium

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15
Q

LANCEFIELD CLASSIFICATION

D (non-enterococci)

A

Streptococcus bovis,
Streptococcus durans

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16
Q

LANCEFIELD CLASSIFICATION

G

A

Streptococcus arginosus

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17
Q

Lancefield Classification & Hemolytic Pattern (Smith & Brown)

Streptococcus pyogenes

A

A & beta

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18
Q

Lancefield Classification & Hemolytic Pattern (Smith & Brown)

Streptococcus agalactiae

A

B & beta

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19
Q

Lancefield Classification & Hemolytic Pattern (Smith & Brown)

Strep. agalactiae subsp. equisimilus

A

C & beta

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20
Q

Lancefield Classification & Hemolytic Pattern (Smith & Brown)

Enterococcus – Streptococcal faecalis

A

D
Alpha or Beta or None

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21
Q

Lancefield Classification & Hemolytic Pattern (Smith & Brown)

Non-enterococcus –Strep. bovis

A

D
Alpha or none

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22
Q

Lancefield Classification & Hemolytic Pattern (Smith & Brown)

Streptococcus pneumoniae

A

NA
Alpha

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23
Q

Lancefield Classification & Hemolytic Pattern (Smith & Brown)

Streptococcus viridans

A

NA
Alpha or none

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24
Q

produces large (1cm in diameter) zones of β hemolysis around
colonies greater that 0.5 mm in diameter

A

Group A β Hemolytic Streptococcus

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25
Q

main human pathogen associated with local or systemic invasion
and post – streptococcal immunologic disorders

A

Group A β Hemolytic Streptococcus

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26
Q

HABITAT:
Skin and Upper Respiratory tract of humans, carried on nasal, pharyngeal, sometimes anal mucosa

A

Group A β Hemolytic Streptococcus

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27
Q

Prone to progression with involvement of deeper tissues and organs, a characteristic that has earned the designation ‘’flesh – eating bacteria”

A

Group A β Hemolytic Streptococcus

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28
Q

Fastidious, requires enriched media for primary isolation incubated with 5% – 10% CO2

A

Streptococcus pyogenes

29
Q

ferment wide variety of carbohydrate with production of lactic acid with or without gas

A

Streptococcus pyogenes

30
Q

Blood agar:

Appears as circular, translucent, grayish to opalescent colonies, matte or glossy large zone beta hemolysis

A

Streptococcus pyogenes

31
Q

Streptococcus pyogenes Morphological, Cultural and Biochemical Characteristics:

Catalase test
PYR
Bacitracin

A

Catalase negative
PYR positive
Bacitracin sensitive

32
Q

test for Group A Streptococcus

A

PYR Hydrolysis Test (POSITIVE)

33
Q

demonstrate presence of pyrrolidonyl arylamidase

A

PYR Hydrolysis Test (POSITIVE)

34
Q

PYR Hydrolysis Test (POSITIVE): develops what color within a minute addition of reagent

A

Cherry red color

35
Q

Bacitracin Susceptibility Test (+) =

A

any presence of ZOI

36
Q

Presumptive test and Used to differentiate Streptococcus pyogenes and
Streptococcus agalactiae

A

Bacitracin Susceptibility Test (+)

37
Q

Bacitracin Susceptibility Test (+)

S. pyogenes
S. agalactiae

A

S. pyogenes (sensitive)
S. agalactiae (resistant)

38
Q

specialized polysaccharide or teichoic acid; found in the surface of the cell wall

A

C - carbohydrate

39
Q

Group A specific cell wall antigen

A

C - carbohydrate

40
Q

use as basis for serological classification using Lancefield method

A

C - carbohydrate

41
Q

Protein antigens:

A

M - Protein
T - Protein

42
Q

Protein antigens:

major virulence factor of group A S pyogenes.

A

M – Protein

43
Q

appears as hair-like projections of the streptococcal cell wall

A

M – Protein

44
Q

Immunity to infection with group A streptococci is related to the presence of type-specific antibodies to _______

A

M – Protein

45
Q

Protein antigens:

acid-labile and heat-labile

A

T – Protein

46
Q

PROTEIN ANTIGENS

obtained from streptococci by proteolytic digestion, which rapidly destroys M proteins.

A

T – Protein

47
Q

PROTEIN ANTIGENS

permits differentiation of certain types of streptococci by agglutination with specific antisera

A

T – Protein

48
Q

allows organism to cling to epithelial surfaces

A

Lipoteichoic Acid (LTA)

49
Q

Cytotoxic; destroys rbc and wbc

A

Lipoteichoic Acid (LTA)

50
Q

most important virulence factor

A

M protein antigen

51
Q

aid in the attachment of the organism to portal of entry

A

M protein antigen

52
Q

Antiphagocytic; promotes invasiveness of the organism

A

Capsule (Hyaluronic acid)

53
Q

depolymerizes DNA; facilitate removal of purulent exudate/ discharges

A

Streptodornase (Streptococcal Deoxyribonuclease)

54
Q

enzymatic activity can be measured by the decrease in viscosity of known DNA solutions.

A

Streptodornase (Streptococcal Deoxyribonuclease)

55
Q

antibody to DNAse develops after streptococcal infections (normal limit = 100 units), especially after skin infections.

A

Streptodornase (Streptococcal Deoxyribonuclease)

56
Q

produced by many strains of group A -hemolytic streptococci.

A

Streptokinase (Fibrinolysin)

57
Q

transforms the plasminogen of human plasma into plasmin, an active proteolytic enzyme that digests fibrin and other proteins.

A

Streptokinase (Fibrinolysin)

58
Q

are antigenic and specific for each bacterial or tissue source.

A

Hyaluronidase

59
Q

splits hyaluronic acid, an important component of the ground substance of connective tissue.

A

Hyaluronidase

60
Q

aids in spreading infecting microorganisms (spreading factor)

A

Hyaluronidase

61
Q

An enzyme elaborated into the environment and is related to the organism’s ability to kill leukocytes, PMN’s and macrophages

A

Diphosphopyridine nucleotidase

62
Q

EXTRACELLULAR ENZYMES

A

A. Streptodornase (Streptococcal Deoxyribonuclease)
B. Streptokinase (Fibrinolysin)
C. Hyaluronidase
D. Diphosphopyridine nucleotidase

63
Q

Hemolysins

oxygen stable; non antigenic : surface BAP hemolysis during aerobic condition

A

Streptolysin S

64
Q

Hemolysins

oxygen labile; antigenic

A

Streptolysin O

65
Q

Immunogenic; responsible for some of the hemolysis seen when growth is in cuts deep into the medium in blood agar plates.

A

Streptolysin O

66
Q

combines quantitatively with antistreptolysin O (ASO)

A

Streptolysin O

67
Q

an antibody that appears in humans following infection with any streptococci that produce streptolysin O.

A

antistreptolysin O (ASO)

68
Q

ASO serum titer in excess of___________ is considered abnormally high and suggests either recent infection with S. pyogenes

A

160–200 Todd units/mL