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Clinical Bacteriology > (M) Lesson 7.3: Gram Positive and Gram Negative Cocci > Flashcards

(M) Lesson 7.3: Gram Positive and Gram Negative Cocci Flashcards

Streptococcus

1
Q
  • Gram-positive cocci in chains
  • Non-motile and non-sporeforming
  • Negative for catalase
  • Facultative anaerobe
  • Pinpoint colony
A

Streptococcus

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2
Q

Laboratory diagnosis basis for suspected Streptococcus?

A

Hemolytic pattern in the BAP

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3
Q
  • Also called Taxo A
  • Uses 0.04 units of Bacitracin
  • Done for beta-hemolytic Streptococcus
  • Confirms Streptococcus pyogenes
  • More important than PYR
A

Bacitracin Susceptibility Test (Taxo A)

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4
Q

Bacitracin Susceptibility Test (Taxo A)

This species results in a susceptible result for Streptococcus pyogenes.

Note: Means highly susceptible to bacitracin and there is no ZOI requirement.

A

Streptococcus pyogenes

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5
Q

Bacitracin Susceptibility Test (Taxo A)

These species results in resistance.

Note: Positive for PYR test

A

Enterococcus faecalis and other Streptococci

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6
Q
  • Identifies Streptococcus pyogenes
  • Follow-up confirmatory test for Bacitracin test
A

PYR Test (L-pyrrolidonyl B-napthylamide)

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7
Q

What is the principle of the PYR Test?

A

Streptococcus pyogenes reacts with PYR because of the added D-dimethylaminocinnamaldehyde

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8
Q

PYR Test

These species test positive (red) for this test.

A
  1. Streptococcus pyogenes
  2. Enterococcus faecalis

Other Streptococci test negative.

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9
Q
  • Principle: Streptococcus agalactiae reacts with CAMP factor that it releases an arrowhead zone of hemolysis upon interaction with the hemolysin of another
A

CAMP Test

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10
Q

CAMP Test

Streptococcus agalactiae releases what type of zone of hemolysis?

A

Arrowhead

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11
Q

CAMP Test

This bacteria is the only one that tests positive for CAMP test denoted by a unique arrowhead zone of hemolysis.

A

Streptococcus agalactiae

Other beta-hemolytic Streptococci test negative.

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12
Q
  • Differentiates Streptococcus agalactiae from other beta-hemolytic cocci
A

Hippurate Hydrolysis Test

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13
Q

Hippurate Hydrolysis Test

Streptococcus agalactiae releases ____ that hydrolyzes hippurate, resulting in a purple-colored cotton upon reaction with ninhydrin.

A

Hippurase

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14
Q

Hippurate Hydrolysis Test

This is the only bacteria that tests positive for this test denoted by a purple complex.

A

Streptococcus agalactiae

Other beta-hemolytic Streptococci test negative.

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15
Q
  • For alpha-hemolysis, green growth in BAP
  • Utilizes optochin
A

Optochin Test

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16
Q
  • An antimicrobial agent
  • Specifically Taxo P
A

Optochin

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17
Q

Optochin Test

P on antibiotic disk indicates?

A

Optochin

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18
Q

Optochin Test

P10 on antibiotic disk indicates?

A

Penicillin

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19
Q

Principle of Optochin Test?

A

Ethyldrocuprein hydrochloride (optochin) inhibits the growth of Streptococcus pneumoniae

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20
Q

Optochin test

Zone of Inhibition must measure ____ or ____ depending on which Taxo P is used by the laboratory for it to be called susceptible.

A

greater than 16 mm or 14 mm

Other alpha-hemolytic Streptococci tests negative.

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21
Q
  • Principle: Under the influence of bile salt (sodium deoxycholate) or detergent, the organism’s cell wall lyses during cell division
  • Streptococcus pneumoniae is bile-soluble
A

Bile Solubility Test

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22
Q

Positive indicator for Bile Solubility Test?

A

A suspension of Streptococcus pneumoniae in a solution of sodium deoxycholate (lyses and the solution becomes clear)

Other alpha-hemolytic Streptococci test negative.

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23
Q
  • For Group D Streptococci
  • Uses bile esculin agar
  • Principle: Group D streptococci and Enterococcus
A

Bile Esculin Hydrolysis Test

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24
Q

These species can grow in the presence of bile and hydrolyzes esculin to esculetin and glucose.

A

Group D Strep and Enterococcus

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25
Q
  • Principle: Enterococcus, Aerococcus, and some species of Pediococcus and leuconostoc can withstand a higher salt concentration than other gram-positive cocci.
  • Differentiates enterococcus from non-enterococcus
A

Salt Tolerance Test

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26
Q

Salt Tolerance Test

Enterococcus, Aerococcus, and some species of Pediococcus and Leuconostoc are halo-tolerant until?

A

6.5% NaCl

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27
Q
  • Identification of Pediococcus species and Leuconostoc species

They disturb biochemical tests because they have similar reactions to Group D enterococcus.

A

Vancomycin Resistant

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28
Q
  • Incubated at room temperature for 5 minutes
  • Enterococcus faecalis and Pediococcus test positive (red)
  • Leuconostoc species test negative (yellow)
A

Leucine Aminopeptidase Test (LAP Test)

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29
Q
  • Incubated at 35°C for 48 hours
  • Enterococcus faecalis tests positive (yellow)
  • Enterococcus faecium tests negative (green)
A

Pyruvate Broth

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30
Q
  • Leuconostoc tests positive (gas formation)
  • Pediococcus tests negative (no gas)
A

MRS Broth Test

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31
Q

____, ____, ____, and ____ tests for beta-hemolytic Streptococcus.

A

Bacitracin, PYR, CAMP, and Hippurate Hydrolysis Test

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32
Q

What are the six important Streptococci?

A
  1. Streptococcus pyogenes
  2. Streptococcus agalactiae
  3. Enterococcus faecalis
  4. Streptococcus bovis
  5. Streptococcus pneomoniae
  6. Viridans group
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33
Q

Classification based on hemolytic pattern or hemolysis

A

Smith and Brown’s

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34
Q

Identify the classification type based on the information provided.

  • Bacteria: Streptococcus pyogenes, Streptococcus agalactiate, Groups C, F, and G
  • Tests: Bacitracin, PYR, CAMP, Hippurate Hydrolysis
A

Beta-Streptococci

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35
Q

Identify the classification type based on the information provided.

  • Bacteria: Streptococcus pneumoniae, Viridans group
  • Tests: Optochin, Bile Solubility
A

Alpha-Streptococci

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36
Q

Identify the classification type based on the information provided.

  • Bacteria: Enterococcus faecalis, Enterococcus faecium, Streptococcus bovis
  • Tests: Bile Esculin Hydrolysis, Salt Tolerance
A

Gamma-Streptococci

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37
Q

Identify the classification type based on the information provided.

  • Small alpha zone surrounded by beta zone
A

Alpha-prime

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38
Q

Type of Classification

  • Confirmatory
  • Based on carbohydrates present on the cell wall of Strep unique to each one
  • Also used for serology
A

Lancefield Classification

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39
Q

What are the different classifications for Lancefield Classification?

A
  • A: Rhamnose-N-acetylglucosamine (S. pyogenes)
  • B: Rhamnose-glucosamine polysaccharide (S. galactiae)
  • C: Rhamnose-N-acetylgalactosamine
  • D: Glycelor teichoic acid (Entero and non-enterococcus)
  • F: Glucopyranosyl-N-acetylgalactosamine
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40
Q

GABS mean?

A

Group A Beta Streptococcus

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41
Q
  • Beta-hemolytic because of its carbohydrate
  • Colonies inhibited by Bacitracin on BAP
  • Bacitracin-susceptible
  • Gram positive cocci in chains
  • Catalase-negative
  • Positive for PYR
A

Group A Streptococcus

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42
Q

Group A Streptococcus

Resides in either ____ or ____

A

Human throat or skin

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43
Q

Infection here is transmitted via direct contact

A

Skin

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44
Q

Group A Streptococcus

If it resides here, it is spread via droplets.

A

Human throat

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45
Q

If it resides here, it is spread via droplets

What are the two cell-associated factors?

A
  1. Hyaluronic Acid
  2. M Protein
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46
Q

Cell-Associated Factors

  • A polysaccharide
  • non-immunogenic, making it not medically important
  • Inhibits phagocytic uptake
  • Easily destroyed once bacteria is released to the environment
A

Hyaluronic Acid

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47
Q

Cell-Associated Factors

  • Are hair-like projections
  • Major virulence factor
  • Anti-phagocytic
  • Antigenic
  • Used to type Group A strep
A

M Protein

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48
Q

Cell-Associated Factors

What are the two hemolysin toxins?

A
  1. Streptolysin O
  2. Streptolysin S
49
Q

Group A Streptococcus

  • Used in serology
  • Immunogenic
  • For RBC lysis
  • Oxygen-labile
A

Streptolysin O

50
Q

Group A Streptococcus

  • Non-immunogenic
  • Oxygen-stable
  • For RBC lysis
A

Streptolysin S

51
Q

Group A Streptococcus

What are three exotoxins?

A
  1. Pyrogenic/Erythrogenic
  2. Phage-coded
  3. Superantigen
52
Q

Group A Streptococcus

  • Allows it to produce fever during infection
A

Pyrogenic/Erythrogenic

52
Q

Group A Streptococcus

  • Cells are lysed by a phage
A

Phage-coded

53
Q
  • Causes fever and rash of scarlet fever
  • Inhibits liver clearance of endotoxin, creating shock-like conditions
A

Exotoxins A-C

54
Q

Group A Streptococcus

  • Activates many helper T-cells by bridging T-cell receptors and MHC class II markers without processed Ag
A

Superantigen

55
Q

Group A Streptococcus

What are the three spreading factors?

A
  1. Streptokinase (fibrinolysin)
  2. Streptococcal DNAse (streptodornase)
  3. Hyaluronidase
56
Q

Group A Streptococcus (Spreading Factors)

  • Breaks down fibrin clot
A

Streptokinase (fibrinolysin)

57
Q

Group A Streptococcus (Spreading Factors)

  • Liquefies pus, extension of lesion
A

Streptococcal DNAse (streptodornase)

58
Q

Group A Streptococcus (Spreading Factors)

  • Hydrolyzes the ground substances of the connective tissues
  • Important to spread in cellulitis
A

Hyaluronidase

59
Q

____ indicates presence of lesions and pus formation

A

Suppurative

60
Q
  • Pharyngitis
  • Scarlet fever
  • Pyoderma/Impetigo
  • Cellulitis, necrotizing fasciitis (flesh-eating bacteria), puerperal fever, lymphangitis, pneumonia, toxic shock-like syndrome
A

Acute (Suppurative) Infection

61
Q

Most common cause of Acute (Suppurative) Infection

A

Streptococcus pyogenes

62
Q

This means “no bacteria present, only its Ag”

A

Non-suppurative

63
Q

This means “there is a prior infection”

A

Sequelae

64
Q
  • Diagnosed through serology, specifically Anti-streptolysin O (ASO)
A

Non-suppurative Sequelae to Group A Streptococcal Infections

65
Q
  • Medical term for sore throat
  • Abrupt onset of sore throat
  • Fever
  • Malaise
  • Headache
  • Tonsillar abscesses
  • Tender anterior cervical lymph nodes
  • Detection: Serological or rapid antigen test, hard to culture
A

Pharyngitis

66
Q
  • Pus-forming skin infection (honey-crusted lesions)
  • Can be caused by Staphylococcus aureus or Streptococcus pyogenes
A

Pyoderma/Impetigo

67
Q
  • Brawny edema
  • Advancing margin of erro
A

Erysipelas (Infection)

68
Q
  • Initially starts with a deep wound that is not treated properly
  • It also contains S. aureus, Pseudomonas, and anaerobes, but predominantly S. pyogenes (flesh-eating bacteria)
A

Necrotizing Fascilitis

69
Q
  • Has signs and symptoms similar to the pharyngitis (except it has rashes observed on the lower extremities)
  • Pastia lines (darkening of groin and armpit area)
  • Triad (highly diagnostic to scarlet fever: rash, pastia lines, strawberry tongue)
A

Scarlet Fever

70
Q
  • Sequelae to: pharyngitis with group A Strep (not Group C)
  • Mechanism: in genetically susceptible individuals, the infection results in production of Ab that crossreact with cardiac antigen
  • Symptoms usually occur 2-3 weeks after pharyngeal infection
A

Rheumatic Fever

71
Q

Determine the test for rheumatic fever.

  • J → joints (Migratory arthritis)
  • <3 carditis
  • N → subcutaneous nodules
  • E → erythma marginatum
  • S → sydenham chorea
A

Jones Criteria (J<3NES)

72
Q

Determine the test for rheumatic fever.

  • Fever
  • Arthralgias
  • Elevated acute phase reactants
A

Minor Jones Criteria

73
Q

What must be needed for the diagnosis of rheumatic fever?

A
  • 2 major or 1 major
  • 2 minor Jones criteria
74
Q
  • Sequelae to pharyngitis or cutaneous streptococcal infection
  • Mechanism: immune complexes bound to glomeruli
  • Kidneys are affected
A

Acute Glumerolonephritis

75
Q

Group A Streptococcus

What are the three treatments?

A
  • Penicillin G → drug of choice (also prevents recurrent Streptococcus pyogenes)
  • Beta-lactam drugs
  • Erythromycin
76
Q

Group A Streptococcus

What is the diagnosis?

A

Taxo A

77
Q

What are the two species under Group B Streptococcus?

A
  1. Streptococcus agalactiae
  2. GBS
78
Q
  • Beta-hemolytic
  • Bacitracin-resistant in BAP
  • Gram-positive cocci in chains
  • Catalase-negative
  • Camp test-positive (CAMP)
A

Group B Streptococcus

79
Q
  • Colonizes the ____ in 15-20% of women
A

Human vagina

80
Q

Group B Streptococcus

What are the two manners of transmission?

A
  1. Newborn infected during birth
  2. Increased with prom
81
Q

Group B Streptococcus

Serve as the main virulence factor

A

Beta-hemolysin

82
Q

When should we treat a mother prior to delivery?

A
  • She had a previous baby with GBS
  • Has documented GBS colonization
  • Prolonged rupture of membranes
83
Q
  • Alpha-hemolytic
  • Optochin-susceptible on BAP
  • Gram-positive lancet-shaped diplococci or in very short chains
  • Lysed by bile (bile-soluble)
A

Streptococcus pneomoniae

84
Q

What are the diseases associated with Group B Streptococci?

A
  1. Neonatal septicemia
  2. Neonatal meningitis
85
Q

Treatment for Group B Streptococci?

A

Ampicillin with Cefortaxime or Gentamicin

86
Q

Reservoir for Streptococcus pneumoniae?

A

Human upper respiratory tract

87
Q

Transmission of Streptococcus pneumoniae?

A

Respiratory droplets

Often colonizes without causing disease

88
Q

Identify the pathogenesis (S. pneumoniae)

For attachment

A

Teichoic acid

89
Q

Identify the pathogenesis (S. pneumoniae)

Main major virulence

A

Polysaccharide capsule

90
Q

Identify the pathogenesis (S. pneumoniae)

  • Characteristic of its sputum
  • Due to the release of fluid and red and white cells stimulated by pneumococcus in alveoli
A

Rusty-colored sputum

91
Q

Identify the pathogenesis (S. pneumoniae)

  • Damages respiratory epithelium
  • It inhibits leukocyte respiratory burst and inhibits classical complement fixation
A

Pneumolysin O

92
Q

Identify the pathogenesis (S. pneumoniae)

Highly inflammatory in CNS

A

Peptidoglycan/Teichoic acid

93
Q

Most common cause especially in >65yrs, but also in infants

A

Streptococcus pneumoniae

94
Q
  • Prevented by pneumococcal vaccines that specifically target S. pneumoniae
  • Symptoms: Big shaking chills, sharp pleural pain, high fever (characteristic)
  • Lobar with productive blood-tinged sputum (rusty-colored)
A

Bacterial Pneumoniae

95
Q

Makes an individual susceptible to pneumonia by S. pneumoniae

A

Predisposing conditions for Pneumonia

96
Q
  • Due to teichoic acid that can pass through the CNS
  • Most common cause among >40 y/o
A

Adult Meningitis

97
Q
  • Most common cause
  • Otitis media → infection of the ears
A

Otitis Media and Sinusitis in children

98
Q
  • In splenectomized patients
A

Septicemia

99
Q

Treatment for Streptococcus Pneumoniae?

A
  • Penicillin G
  • Resistance due to chromosomal alteration in penicillin-binding proteins (treat with Vancomycin and Rifampin)
  • Prevented with vaccination
100
Q

The only streptococcus without Lancefield classification

A

Streptococcus pneumoniae

101
Q

Three species under Viridans streptococci?

A

Streptococcus singuis
Streptococcus mutans
Streptococcus mitis

102
Q
  • Alpha-hemolytic
  • Optochin-resistant
  • G(+) in chains
  • Not bile-soluble
A

Viridans Streptococci

103
Q

Reservoir for Viridans Streptococci?

A

Human oropharynx (as normal flora, more predominant in URT)

104
Q
  • Caused by S. mutans
  • Dextran-mediated adherence glues oral flora onto teeth, forming plaque and causing caries
A

Dental Carries

105
Q
  • Catalase-negative
  • PYR positive
  • Hydrolyzes esculin in 40% bile
  • Halo-tolerant (can grow under 6.5% NaCl)
A

Enterococcus (Group D Streptococcus)

106
Q
  • Symptoms:
    Malaise
    Fatigue
    Anorexia
    Night sweats
    Weight loss
A

Subacute infective endocarditis

106
Q

What are the predisposing factors for Viridans streptococci?

A
  • Makes an individual highly susceptible
  • Damage (or prosthetic) heart valve
  • Dental work w/o prophylactic antibiotics
  • Extremely poor oral hygiene
107
Q

Pathogenesis for Viridans streptococci?

A

Dextran (biofilm)-mediated adherence

108
Q

Treatment for Viridans Streptococci?

A

Penicillin G with aminoglycoside for endocarditis

109
Q

Also called Streptococcus faecalis
Group D, G(+) cocci in chains
PYR (+)
Catalase (-)
Varied hemolysis
Hydrolyzes esculin in 40% bile
Grows in 6.5% NaCl

A

Enterococcus faecalis

110
Q

Reservoir for Enterococcus faecalis?

A
  • Human colon
  • Urethra
  • Female genital tract
111
Q

Henlo, please look at the pathogenesis for Enterococcus faecalis <3

A

IDK HOW TO CARDS IT

112
Q

What are the diseases associated with Enterococcus faecalis?

A
  1. Urinary, biliary tract infection
  2. Infective endocarditis (SBE)
113
Q

T or F: Some vancomycin-resistant strains of Enterococcus faecium or E. faecalis have no reliable effective treatment

A

T

114
Q

Familiarize yourself with the prevention for E. faecalis

A

Prophylactic use of beta-lactam drugs: penicillin and gentamicin in px w/ damaged heart valves prior to intestinal or urinary tract manipulation

115
Q

What are the two important Non-Enterococci?

A
  1. Streptococcus bovis
  2. Streptococcus equinus
116
Q

Hi, madaming table for Non-Enterococci, please just study them. </3

A

GOOOO (OR GO TO THE NEXT DECK IDK)

Clinical Bacteriology (22 decks)

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