Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Liz's Microbiology Module 1 > Streptococcaceae and Other Related Genera > Flashcards

Streptococcaceae and Other Related Genera Flashcards

(98 cards)

Start Studying
1
Q

When comparing staph and strep colonies, what are the differences?

A
  • Staph is opaque

- Strep is “transparent” (or at least not as opaque)

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

Alpha (or gamma) hemolytic Streps

A
  • Group D
  • S. pneumoniae
  • Enterococcus sp.
  • Alpha Strep (not Group D)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Beta hemolytic Streps

A
  • Group A
  • Group B
  • Group D (rarely beta hemolytic)
  • Enterococcus spp. (rarely beta hemolytic)
  • Beta Strep (not Group A, B, or D)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

S. pneumoniae characteristic features on a plate

A
  • Colonies are often depressed in center (autolysis) or mucoid (encapsulated)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Throat cultures (strep screens) must be incubated ____?

A

Anaerobically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Streptolysin O is ____ ____

A

Oxygen labile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Streptolysin S is ____ ____

A

Oxygen stable

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

Principle of the Lancefield grouping test

A

Grouped by “C substance” in cell wall

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

Streptococci

- Catalase (pos/neg)

A

Catalase negative

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

Bile Esculin hydrolysis

- Principle

A

To determin an organism’s ability to hydrolyze esculin to esculetin in presence of bile. Esculetin reacts w/ Fe citrate in medium to form black ppt

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

Bile Esculin agar

- What do pos/neg tests look like?

A

Pos: blackening of medium
Neg: no blackening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

LAP

- Principle

A

To determine organism’s ability to produce the enzyme leucine aminopeptidase, which will hydrolyze leucine-a-naphthylamide disk

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

LAP

- What do pos/neg tests look like?

A

Pos: red
Weak pos: pink
Neg: yellow

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

- Principle

A

To determine an organism’s ability to grow in a high salt environment (6.5%)

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

- What do pos/neg tests look like?

A

Pos: turbid
Neg: clear, no change

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

PYR

- Principle

A

To determine an organism’s ability to produce the enzyme pyrrolidonyl peptidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

PYR

- What do pos/neg tests look like?

A

Pos: red
Neg: no color change

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

Optochin susceptibility test

- Principle

A

To determine an organism’s susceptibility to the chemical optochin (ethylhydrocupreine hydrochloride)

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

Optochin susceptibility test

- What do pos/neg tests look like?

A

Pos: zone of inhibition >= 14 mm
Neg: no zone of inhibition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Bile solubility

- Principle

A

To determine the ability of organisms to lyse in presence of bile salt (sodium desoxycholate)
- Plate and tube method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Bile solubility

- What do pos/neg tests look like?

A

Plate
- Pos: disintegration of colony under desoxycholate drop (flat hemolyzed area remains)
- Neg: no visible change under desoxycholate drop
Tube
- Pos: clearing of “test” but “control” remains turbid (cloudy)
- Neg: both tubes (“test” and “control”) remain turbid (cloudy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Quellung test

- Principle

A

To determine the ability of the organism’s capusle Ags to bind to known Abs forming a precipitate. Visualized w/ the addition of methylene blue to the slide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Quellung test

- What do pos/neg tests look like?

A

Pos: capsule looks opaque and appears to enlarge around dark blue-stained cell
Neg: no appearance of a clear, enlarged halo surrounding stained cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Bacitracin

- Principle

A

To detect an oganism’s susceptibility to the anitmicrobial agent bacitracin. Filter paper disks impregnated w/ bacitracin are sued to determine susceptibility or resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Bacitracin | - What do pos/neg tests look like?
Pos: zone of inhibition Neg: no zone of inhibiton
26
CAMP test | - Principle
To detect presence of CAMP factor produced by certain organisms that will enhance the beta-hemolytic activity of S. aureus on SBA
27
Sodium Hippurate | - Principle
Hippuric acid is hydrolyzed to benzoic acid and glycine by hippuricase. Glycine end product is detected by addition of ninhydrin reagent
28
Sodium Hippurate | - What do pos/neg tests look like?
Pos: dark blue to purple color Neg: no color change
29
Other grouping tools for determining Streptococcus and Enterococcus
- Ag testing (in/direct) - Fluorescent Ab (esp. Group A) - Kit systems (API, Vitek, etc.)
30
Latex agglutination | - Principle
To dtect certain Ags or Abs in a variety of bodily fluids (blood, saliva, urine, CSF). Sample to be tested is sent to the lab where it's mixed w/ latex beads coated w/ a specific Ag or Ab.
31
Coagglutination | - Principle
Method used for organism identification using specific, known commercial Abs taht have been attached to a dead bacterium, most often Staphylococcus. Dead Staphylococcus act similarly to a latex bead, allowing Ag-Ab reaction to be visible to the naked eye
32
Coagglutination | - What do pos/neg tests look like?
Pos: visible agglutination w/in 1-2 minutes Neg: remain smooth
33
2 types of Ag testing for Streptococcus and Enterococcus sp.
Latex agglutination and coagglutination
34
Who is/are PYR positive?
- Group A | - Enterococcus spp.
35
Who is/are NaHippurate positive?
- Group B
36
Who is bacitracin susceptible?
Group A
37
What Strep are LAP positive?
All of them we work with in the lab
38
What test did we use coagglutination on in the lab?
Group B
39
Who is/are quellung test positive?
S. pneumoniae
40
Name all of the ALPHA and gamma hemolytic Strep
- S. pneumoniae - Enterococcus sp. - Alpha Streptococci (Group D) - Alpha Streptococci (not Group D)
41
Who is/are CAMP positive?
Group B
42
Tests to run on when you have catalase negative GPCs that are alpha/gamma hemolytic
- Esculin - NaCl - PYR - Bile solubility - Optochin
43
Name all of the BETA hemolytic Strep
- Enterococcus sp (rare) - Beta Streptococci (Group D) (rare) - Beta Streptococci (Group A) - Beta Streptococci (Group B) - Beta Streptococci (not Group A, B, D)
44
Who is/are bile solubility positive?
S. pneumoniae
45
Tests to run when you have catalase negative GPCs that are beta hemolytic?
- PYR - Esculin - Bacitracin - CAMP - NaHippurate - Coagglutination (not specific for group B but that's what we used it for)
46
Who can be a pseudocatalase (weak catalase positive)?
Enterococcus sp.
47
Who is/are positive for bile esculin?
- Enterococcus sp | - Alpha Streptococci (Group D)
48
Who is/are optochin susceptible?
S. pneumoniae
49
Who is/are NaCl positive?
- Group B | - Enterococcus sp
50
Group A/S. pyogenes - Hemolysis - 2 positive/susceptible tests
- Beta - Bacitracin susceptible - PYR positive
51
Group B/S. agalactiae - Hemolysis - 3 positive tests
- Beta - CAMP pos - NaCl pos - NaHippurate pos
52
Not Group A, B, or D are otherwise known as...?
Group C, G
53
Group D/S. bovis - Hemolysis - 1 positive test
- Usually alpha or gamma (rarely beta) | - Esculin pos
54
S. pneumoniae - Hemolysis - 3 positive tests
- Alpha - Optochin susceptible - Bile solubility pos - Quellung pos
55
Enterococcus sp - Hemolysis - 3 positive tests
- Alpha (rarely beta) - Esculin pos - NaCl pos - PYR pos
56
Virulence factors of Group A
- M protein - Pyrogenic/erythrogenic toxin - Streptokinase/fibrinolysin - Hyaluronidase
57
M protein
Major virulence factor in Group A Strep; resistant to phagocytosis
58
Pyrogenic/erythrogenic toxin
Causes the rash of scarlet fever
59
Streptokinase/fibrinolysin
Fibrinolysin is the breakdown of fibrin; allows infection to spread (cellulitis, erysipelas)
60
Hyaluronidase
Break down of ground substance; allows infections to spread
61
Pyogenic streptococci
"pus forming" - Group A - Group B - Groups C, G
62
Common infections caused by Group A Strep
Throat and wound - "Strep throat", tonsillitis - Scarlet fever - Impetigo - Erysipelas - Cellulitis - Necrotizing fasciitis
63
What type of toxin is a pyrogenic toxin?
Exotoxin
64
Group A Strep - Lacefield group - ____ colonies w/ ____ zone of beta hemolysis
- Lancefield group A | - Large colonies; large zone
65
Streptococcal Toxic Shock Syndrome | - Cause by which group of strep?
Group A
66
Group A Post streptococcal diseases
- Acute glomerulonephritis | - Rheumatic fever
67
Acute Glomerulonephritis - Caused by... - Time of infection?
- Ag-Ab complexes causes inflammation of glomeruli (NOT an infection of the kidneys) - Occurs 1-2 weeks following pharyngitis or skin infection w/ Group A
68
Acute Rheumatic Fever - Cause - Location of disease - Patient population - Time of infection?
- Cross-reaction b/w strep Ag and cardiac tissue - Results in damage to heart valves - Most frequent in 5-15 year olds - Occurs 2-4 weeks after pharyngitis
69
Oxygen requirements for Streptococcus Genera
Aerobic or facultative anaerobic
70
Throat cultures are usually ordered for what group of strep?
Group A; other beta strep aren't often treated
71
SXT plate
Inhibits normal flora allowing Group A to grow
72
SBA is incubated ____ for Group A "strep screens"
Anaerobically
73
Throat "rapid strep screens" - Direct Ag detection of Group A strep - ____ specificity, ____ sensitivity
- Ag-Ab interaction b/w Ag in specimen and Ab in test kit - High; Low → conclusive for pos tests; if patient is symptomatic and direct Ag test is negative, culture should be performed
74
Group A strep treatment
GROUP A STREP IS UNIVERSALLY SUSCEPTIBLE TO PENICILLIN
75
Group B strep - Lancefield group - ____ colonies, ____ hemolytic zone compared to Group A
- Lancefield Group B | - Large; smaller
76
Group B strep may be part of normal ____ flora
Urogenital
77
Infections caused by Group B
- Meningitis/septicemia in newborns - Female genital and UTIs - Post-partum infections
78
CDC guidelines for Group B strep culture during pregnancy
- Should be done for all pregnant women at 35-37 weeks gestation - Culture/screen should include vaginal and rectal collection - LIM broth (has antibiotics) suppresses GN normal flora - If screen/culture is positive, moms need to be treated w/ penicillin
79
Group B Strep | - Post partum infections
- Early onset disease of Group B | - Late onset disease of Group B
80
Early onset disease of Group B
- Baby is < 7 days old - Results from vertical transmission (during delivery) - High mortality
81
Late onset disease of Group B
- Baby is 1 week to 3 months old | - More than often from parents, caretakers, nosocomial infections
82
Group B | - Gram stain
- GP | - Tiny, round diplococci
83
Groups C, G strep
S. dysgalactiae
84
Groups C, G - Infections - Differentiation
May cause pharyngitis (not usually treated) - Lower incidence of post streptococcal diseases - Not differentiated unless found in blood or CSF (reported as beta streptococci not Group A, B, or D)
85
S. pneumoniae | - Clinical infections
- Community acquired bacterial cause of pneumonia - Meningitis, otitis media (ear infection) - Carriers asymptomatic (esp in young children)
86
S. pneumoniae | - Treatment and prevention
- Becoming more resistant to antimicrobials | - Vaccinations available for young and older
87
S. pneumoniae - Gram stain - Colonial morphology - Growth requirement
- GP diplococci (football, lancet shaped) or chains - Mucoid (encapsulated) or dipped (autolysis) → virulence, typing - Capnophilic
88
Viridans Streptococci | - 5 major groups (each w/ multiple species)
- S. salivarius group - S. anginosus group - S. mitis group - S. mutans group - S. bovis group
89
Viridans strep | - Causes...
- Subacute endocarditis | - Oral infections (gingivitis and cavities)
90
Which of the 5 major Viridans strep groups has the D Ag?
S. bovis
91
Viridans strep - Hemolysis - LAP pos/neg - Bile esculin pos/neg - NaCl pos/neg - Optochin pos/neg
- Alpha/gamma hemolytic (less commonly beta hemolytic) - Not usually further identified unless from blood or CSF cultures - All are LAP + - Bile esculin neg (except for S. bovis) - NaCl neg - Optochin neg - Reported as either: alpha Streptococci (Gp D) or (not Gp D)
92
Group D Strep - Normal flora - Causes...
- Gastrointestinal flora | - Septicemia (positive blood cultures)
93
Viridans Strep | - Normal flora
Oral, GI, skin
94
Enterococcus sp - Normal flora - Infections - Most common species
- Gastrointestinal - Mainly UTI, septicemia, abdominal wounds - E. faecalis (more common), E. faecium (more resistant)
95
Enterococcus sp - Gram stain - Drug resistance to...
- GPC, often elongated | - Multiple drug resistance (VRE → vancomycin drug resistance)
96
Abiotrophia - Found in ____ and ____ - Culture ____ endocarditis - Media
- Bacteremia; endocarditis - Negative - Chocolate agar or S. aureus satellitism
97
Aerococcus sp - Gram stain - Culture morphology - Lap pos/neg
- GPC tetrads or clusters (like Staph) - Alpha/gamma hemolysis (like Strep) - Lap neg
98
Vancomycin Resistant "Lactic Acid Bacteria" - 2 species - produces which CHO? - Similar in appearance to ____
- Leuconostoc species, Pediococcus species - Produces only lactic acid from glucose fermentation (as do Strep) - Similar in appearance to "viridans Streptococci"

Liz's Microbiology Module 1 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions