(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
* **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
Salt Tolerance Test
26
# Salt Tolerance Test Enterococcus, Aerococcus, and some species of Pediococcus and Leuconostoc are halo-tolerant until?
6.5% NaCl
27
* Identification of Pediococcus species and Leuconostoc species ## Footnote They disturb biochemical tests because they have similar reactions to Group D enterococcus.
Vancomycin Resistant
28
* Incubated at room temperature for 5 minutes * Enterococcus faecalis and Pediococcus test **positive (red)** * Leuconostoc species test **negative (yellow)**
Leucine Aminopeptidase Test (LAP Test)
29
* Incubated at 35°C for 48 hours * Enterococcus faecalis tests **positive (yellow)** * Enterococcus faecium tests **negative (green)**
Pyruvate Broth
30
* Leuconostoc tests **positive (gas formation)** * Pediococcus tests **negative (no gas)**
MRS Broth Test
31
____, ____, ____, and ____ tests for beta-hemolytic Streptococcus.
Bacitracin, PYR, CAMP, and Hippurate Hydrolysis Test
32
What are the six important Streptococci?
1. Streptococcus pyogenes 2. Streptococcus agalactiae 3. Enterococcus faecalis 4. Streptococcus bovis 5. Streptococcus pneomoniae 6. Viridans group
33
Classification based on hemolytic pattern or hemolysis
Smith and Brown's
34
# 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
Beta-Streptococci
35
# Identify the classification type based on the information provided. * **Bacteria:** Streptococcus pneumoniae, Viridans group * **Tests:** Optochin, Bile Solubility
Alpha-Streptococci
36
# Identify the classification type based on the information provided. * **Bacteria:** Enterococcus faecalis, Enterococcus faecium, Streptococcus bovis * **Tests:** Bile Esculin Hydrolysis, Salt Tolerance
Gamma-Streptococci
37
# Identify the classification type based on the information provided. * Small alpha zone surrounded by beta zone
Alpha-prime
38
# Type of Classification * Confirmatory * Based on carbohydrates present on the cell wall of Strep unique to each one * Also used for serology
Lancefield Classification
39
What are the different classifications for Lancefield Classification?
* 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
40
GABS mean?
Group A Beta Streptococcus
41
* Beta-hemolytic because of its carbohydrate * Colonies inhibited by Bacitracin on BAP * Bacitracin-susceptible * Gram positive cocci in chains * Catalase-negative * Positive for PYR
Group A Streptococcus
42
# Group A Streptococcus Resides in either ____ or ____
Human throat or skin
43
Infection here is transmitted via **direct contact**
Skin
44
# Group A Streptococcus If it resides here, it is spread via **droplets.**
Human throat
45
# If it resides here, it is spread via droplets What are the two cell-associated factors?
1. Hyaluronic Acid 2. M Protein
46
# Cell-Associated Factors * A polysaccharide * non-immunogenic, making it not medically important * Inhibits phagocytic uptake * Easily destroyed once bacteria is released to the environment
Hyaluronic Acid
47
# Cell-Associated Factors * Are hair-like projections * Major virulence factor * Anti-phagocytic * Antigenic * Used to type Group A strep
M Protein
48
# Cell-Associated Factors What are the two hemolysin toxins?
1. Streptolysin O 2. Streptolysin S
49
# Group A Streptococcus * Used in serology * Immunogenic * For RBC lysis * Oxygen-labile
Streptolysin O
50
# Group A Streptococcus * Non-immunogenic * Oxygen-stable * For RBC lysis
Streptolysin S
51
# Group A Streptococcus What are three exotoxins?
1. Pyrogenic/Erythrogenic 2. Phage-coded 3. Superantigen
52
# Group A Streptococcus * Allows it to produce fever during infection
Pyrogenic/Erythrogenic
52
# Group A Streptococcus * Cells are lysed by a phage
Phage-coded
53
* Causes fever and rash of scarlet fever * Inhibits liver clearance of endotoxin, creating shock-like conditions
Exotoxins A-C
54
# Group A Streptococcus * Activates many helper T-cells by bridging T-cell receptors and MHC class II markers without processed Ag
Superantigen
55
# Group A Streptococcus What are the three spreading factors?
1. Streptokinase (fibrinolysin) 2. Streptococcal DNAse (streptodornase) 3. Hyaluronidase
56
# Group A Streptococcus (Spreading Factors) * Breaks down fibrin clot
Streptokinase (fibrinolysin)
57
# Group A Streptococcus (Spreading Factors) * Liquefies pus, extension of lesion
Streptococcal DNAse (streptodornase)
58
# Group A Streptococcus (Spreading Factors) * Hydrolyzes the ground substances of the connective tissues * Important to spread in cellulitis
Hyaluronidase
59
____ indicates presence of lesions and pus formation
Suppurative
60
* Pharyngitis * Scarlet fever * Pyoderma/Impetigo * Cellulitis, necrotizing fasciitis (flesh-eating bacteria), puerperal fever, lymphangitis, pneumonia, toxic shock-like syndrome
Acute (Suppurative) Infection
61
Most common cause of Acute (Suppurative) Infection
Streptococcus pyogenes
62
This means "no bacteria present, only its Ag"
Non-suppurative
63
This means "there is a prior infection"
Sequelae
64
* Diagnosed through serology, specifically Anti-streptolysin O (ASO)
Non-suppurative Sequelae to Group A Streptococcal Infections
65
* 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
Pharyngitis
66
* Pus-forming skin infection *(honey-crusted lesions)* * Can be caused by **Staphylococcus aureus** or **Streptococcus pyogenes**
Pyoderma/Impetigo
67
* Brawny edema * Advancing margin of erro
Erysipelas (Infection)
68
* 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)
Necrotizing Fascilitis
69
* 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)*
Scarlet Fever
70
* **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
Rheumatic Fever
71
# Determine the test for rheumatic fever. * J → joints (Migratory arthritis) * <3 carditis * N → subcutaneous nodules * E → erythma marginatum * S → sydenham chorea
Jones Criteria (J<3NES)
72
# Determine the test for rheumatic fever. * Fever * Arthralgias * Elevated acute phase reactants
Minor Jones Criteria
73
What must be needed for the diagnosis of rheumatic fever?
* 2 major or 1 major * 2 minor Jones criteria
74
* **Sequelae** to pharyngitis or cutaneous streptococcal infection * **Mechanism:** immune complexes bound to glomeruli * Kidneys are affected
Acute Glumerolonephritis
75
# Group A Streptococcus What are the three treatments?
* Penicillin G → drug of choice *(also prevents recurrent Streptococcus pyogenes)* * Beta-lactam drugs * Erythromycin
76
# Group A Streptococcus What is the diagnosis?
Taxo A
77
What are the two species under Group B Streptococcus?
1. Streptococcus agalactiae 2. GBS
78
* Beta-hemolytic * Bacitracin-resistant in BAP * Gram-positive cocci in chains * Catalase-negative * Camp test-positive (CAMP)
Group B Streptococcus
79
* Colonizes the ____ in 15-20% of women
Human vagina
80
# Group B Streptococcus What are the two manners of transmission?
1. Newborn infected during birth 2. Increased with prom
81
# Group B Streptococcus Serve as the main virulence factor
Beta-hemolysin
82
When should we treat a mother prior to delivery?
* She had a previous baby with GBS * Has documented GBS colonization * Prolonged rupture of membranes
83
* Alpha-hemolytic * Optochin-susceptible on BAP * Gram-positive lancet-shaped diplococci or in very short chains * Lysed by bile (bile-soluble)
Streptococcus pneomoniae
84
What are the diseases associated with Group B Streptococci?
1. Neonatal septicemia 2. Neonatal meningitis
85
Treatment for Group B Streptococci?
Ampicillin with Cefortaxime or Gentamicin
86
Reservoir for Streptococcus pneumoniae?
Human upper respiratory tract
87
Transmission of Streptococcus pneumoniae?
Respiratory droplets ## Footnote Often colonizes without causing disease
88
# Identify the pathogenesis (S. pneumoniae) For attachment
Teichoic acid
89
# Identify the pathogenesis (S. pneumoniae) Main major virulence
Polysaccharide capsule
90
# 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
Rusty-colored sputum
91
# Identify the pathogenesis (S. pneumoniae) * Damages respiratory epithelium * It inhibits leukocyte respiratory burst and inhibits classical complement fixation
Pneumolysin O
92
# Identify the pathogenesis (S. pneumoniae) Highly inflammatory in CNS
Peptidoglycan/Teichoic acid
93
Most common cause especially in >65yrs, but also in infants
Streptococcus pneumoniae
94
* 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)
Bacterial Pneumoniae
95
Makes an individual susceptible to pneumonia by S. pneumoniae
Predisposing conditions for Pneumonia
96
* Due to teichoic acid that can pass through the CNS * Most common cause among >40 y/o
Adult Meningitis
97
* Most common cause * Otitis media → infection of the ears
Otitis Media and Sinusitis in children
98
* In splenectomized patients
Septicemia
99
Treatment for Streptococcus Pneumoniae?
* Penicillin G * Resistance due to chromosomal alteration in penicillin-binding proteins *(treat with Vancomycin and Rifampin)* * Prevented with vaccination
100
The only streptococcus without Lancefield classification
Streptococcus pneumoniae
101
Three species under Viridans streptococci?
Streptococcus singuis Streptococcus mutans Streptococcus mitis
102
* Alpha-hemolytic * Optochin-resistant * G(+) in chains * Not bile-soluble
Viridans Streptococci
103
Reservoir for Viridans Streptococci?
Human oropharynx (as normal flora, more predominant in URT)
104
* Caused by S. mutans * Dextran-mediated adherence glues oral flora onto teeth, forming plaque and causing caries
Dental Carries
105
* Catalase-negative * PYR positive * Hydrolyzes esculin in 40% bile * Halo-tolerant (can grow under 6.5% NaCl)
Enterococcus (Group D Streptococcus)
106
* **Symptoms:** Malaise Fatigue Anorexia Night sweats Weight loss
Subacute infective endocarditis
106
What are the predisposing factors for Viridans streptococci?
* Makes an individual highly susceptible * Damage (or prosthetic) heart valve * Dental work w/o prophylactic antibiotics * Extremely poor oral hygiene
107
Pathogenesis for Viridans streptococci?
Dextran (biofilm)-mediated adherence
108
Treatment for Viridans Streptococci?
Penicillin G with aminoglycoside for endocarditis
109
Also called Streptococcus faecalis Group D, G(+) cocci in chains PYR (+) Catalase (-) Varied hemolysis Hydrolyzes esculin in 40% bile Grows in 6.5% NaCl
Enterococcus faecalis
110
Reservoir for Enterococcus faecalis?
* Human colon * Urethra * Female genital tract
111
Henlo, please look at the pathogenesis for Enterococcus faecalis <3
IDK HOW TO CARDS IT
112
What are the diseases associated with Enterococcus faecalis?
1. Urinary, biliary tract infection 2. Infective endocarditis (SBE)
113
T or F: Some vancomycin-resistant strains of Enterococcus faecium or E. faecalis have no reliable effective treatment
T
114
Familiarize yourself with the prevention for E. faecalis
Prophylactic use of beta-lactam drugs: penicillin and gentamicin in px w/ damaged heart valves prior to intestinal or urinary tract manipulation
115
What are the two important Non-Enterococci?
1. Streptococcus bovis 2. Streptococcus equinus
116
Hi, madaming table for Non-Enterococci, please just study them.
GOOOO (OR GO TO THE NEXT DECK IDK)