Streptococcus Flashcards
1
Q
Streptococcus
They belong to the family
A
STREPTOCOCCACEAE
2
Q
Streptococcus
● Some species are part of the indigenous human microbiota
○ Some species are______
A
CAPNOPHILIC
Place in candle jar
3
Q
Streptococcus
● Their growth is enhanced by____, _____ or _____ that is incorporated in culture media
A
blood, serum or glucose
4
Q
● All streptococci except (2) the are included in the Lancefield
classification
A
VIRIDANS GROUP and S. pneumoniae
5
Q
Streptococcus
MICROSCOPY:
A
Gram (+) spherical cells that are arranged in chains or pairs.
6
Q
Streptococcus
CULTURE:
A
Appear grayish, pinpoint, and translucent to slightly opaque while some species have mucoid colonies
7
Q
Streptococcus
BIOCHEMICAL TESTS:
A
Catalase (-)
Oxidase and Gas production (-)
non motile
ferments carbohydrates
8
Q
Streptococcus
NOTORIOUS PATHOGENS:
A
Streptococcus pyogenes
Streptococcus pneumoniae
9
Q
CLASSIFICATION OF STREPTOCOCCI
A
ACADEMIC/ BERGEY’S CLASSIFICATION
SMITH AND BROWN CLASSIFICATION
LANCEFIELD CLASSIFICATION
10
Q
Classification
● Based on TEMPERATURE REQUIREMENT
A
ACADEMIC/ BERGEY’S CLASSIFICATION
11
Q
Classification
● Based on HEMOL YTIC PATTERNS
A
SMITH AND BROWN CLASSIFICATION
12
Q
Classification
● Based on the extraction of C CARBOHYDRATE from
streptococcal cell wall.
A
LANCEFIELD CLASSIFICATION
13
Q
Staph vs strep
Colonies
A
Staph: Larger, mucoid
Strep: Small-medium, pinpoint (very evident zone of hemolysis)
14
Q
Flesh eating bacteria
A
S. pyogenes
15
Q
Meningitis
A
S. agalactiae
16
Q
Only grows @ 37°C
A
Pyogenic group
17
Q
Pyogenic group ate
● Mostly __-hemolytic
A
β
18
Q
Pyogenic group includes
A
● S. pyogenes
● Groups C and G streptococci
19
Q
● Can grow at 45°C & 37°C
A
Viridans group
20
Q
Viridans group
● NOT PART of the lancefield
Group but some are___-hemolytic
A
α
21
Q
● Can grow at 10°C & 37°C
A
Lactic group
22
Q
Lactic group
●___-hemolytic and has
Lancefield N antigen
A
Non hemolytic
23
Q
● Often found in dairy products
●_____, causes normal
coagulation and souring of milk
A
Lactic group
S. lactis
24
Q
● Can grow at 10°C, 45°C & 37°C
A
Enterococcus group
25
Enterococcus
● Part of normal microbiota of the
human____
● ______
intestine
E. faecalis
26
ALPHA HEMOLYTIC STREPTOCOCCI
Describe and give 2 examples
● They have partial/ incomplete
hemolysis of red blood cells
around the colonies
● For the culture, greenish or incomplete hemolysis
● S. pneumoniae and Viridans group
27
BETA HEMOLYTIC STREPTOCOCCI
Description and examples
● Exhibit a complete lysis of red
blood cells
● Clear zone of hemolysis around
the colony
● S. pyogenes, S. agalactiae
28
GAMMA HEMOLYTIC STREPTOCOCCI
Description and examples
● Do not exhibit the lysis of red
blood cells
● The RBC surround the colony
are unaffected
● S. bovis or E. faecalis
29
Lancefield classification
________, the microbiologist who
developed the classification method
○ found out that the ______can be
extracted from he streptococcal cell wall by placing the organism in _____
and heating the suspension for____
Rebecca Lancefield
C carbohydrates
dilute acetic acid
10 minutes
30
● It is most significant in classifying and identifying beta-hemolytic streptococci
Lancefield classification
31
HEMOLYTIC PATTERN - ***B***
LANCEFIELD GROUP
SPECIES
A - S. pyogenes
B - S. agalactiae
C - S. agalactiae subsp. equisimilis
32
HEMOLYTIC PATTERN
***Alpha or Gamma***
***Alpha, Beta or Gamma***
LANCEFIELD GROUP
SPECIES
D - S. bovis
D - Enterococci
33
HEMOLYTIC PATTERN
***Alpha, Beta or Gamma***
LANCEFIELD GROUP
SPECIES
None but some of the strains may have A, C, F, G or N
Viridans
34
pneumonia and viridans don’t have ___
C carbohydrates
35
LANCEFIELD GROUP SUGARS
GROUP A
GROUP B
GROUP C
N - acetylglucosamine
Rhamnose - glucosamine
Rhamnose - n - acetylglucosamine
36
LANCEFIELD GROUP SUGAR
GROUP D
Glycerol teichoic
37
LANCEFIELD GROUP SUGAR
GROUP F
Glucopyranosyl –N– acetylglucosamine
38
T or F
GAS
● It is not considered as part of the indigenous microbiota
● It is pathogenic to humanity
True
39
GAS
● It is acquired through_______ that are released through coughing or sneezing
● Highly resistant to____ and can be recovered from swabs several hours after the collection
CONTAMINATED DROPLETS
DRYING
40
GAS
The species for this group is ***Streptococcus pyogenes*** which is
________ and _______
(involves deeper tissues and organs)
FEVER-PRODUCING AND FLESH EATING BACTERIA
41
S. pyogenes
● The principal virulence factor is______
PROTEIN M
42
○ Attached to the peptidoglycan
○ Antiphagocytic
○ Adherence to the mucosal cells
Protein M of S. pyogenes
43
GAS
● Culture on BAP:
colonies are small, translucent,
smooth and exhibit well-defined beta hemolysis
44
GROUP A (ENZYMES AND TOXINS)
HEMOLYSINS
ENZYMES
TOXINS
STREPTOLYSIN O
STREPTOLYSIN S
DEOXYRIBONUCLEASE (DNase)
HYALURONIDASE
PYOGENIC TOXINS - Serotypes
A, B, C and F
45
○ Responsible for the subsurface
hemolysis on BAP that is
incubated anaerobically
STREPTOL YSIN O
46
○ High antigenic and induces
antibody response
○ Serological test to be used to
detect recent infections with S.
pyogenes is the_______
STREPTOLYSIN O
ANTI-STREPTOLYSIN O (ASO)
47
= POSITIVE ASO
<200 Todd Units/ mL (IU/mL)
48
○ It is an oxygen - stable hemolysin and non-antigenic
○ Responsible for the surface
hemolysis on BAP that is
incubated
STREPTOLYSIN S
49
It lowers the viscosity of exudates giving the pathogens more mobility
DEOXYRIBONUCLEASE (DNase)
50
DEOXYRIBONUCLEASE (DNase)
Four types:
Antigenic Enzymes A, B, C, D
51
It causes fibrin clot lysis
STREPTOKINASE
52
A protein that binds to plasminogen and activates the production of plasmin.
Streptokinase
53
It activates a host blood factor that dissolves fibrin clots.
Streptokinase
54
Solubilizes the ground substance of mammalian tissues.
HYALURONIDASE
55
PYROGENIC TOXINS -
SEROTYPES A, B, C and F
56
Refers as super antigens
PYROGENIC TOXINS -
57
Pyrogenic toxins
Formerly known as______
ERYTHROGENIC TOXINS
58
degrades proteins and mediates
- rashes that are caused by Scarlet Fever.
EXOTOXIN B (Cysteine Protease)
59
OTHER VIRULENCE FACTOR
Protein F
Lipoteichoic Acid
Hyaluronic Acid Capsule
Hemolysins, Toxins & Enzymes
60
GROUP A (RELATED INFECTIONS/ DISEASE)
PHARYNGITIS OR TONSILLITIS (Strep
Throat)
SCARLET FEVER (SCARLATINA)
CELLULITIS
ERYSIPELAS
IMPETIGO
RHEUMATIC HEART FEVER
ACUTE GLOMERULONEPHRITIS
STREPTOCOCCAL TOXIC SHOCK SYNDROME
61
● It is spread by air droplets and
close contact
● Its diagnosis relies on the culture of specimen (throat swab) or direct antigen detection
PHARYNGITIS OR TONSILLITIS (Strep Throat)
62
● Caused by the release of pyrogenic toxins
● Associated with STRAWBERRY COLORED TONGUE
SCARLET FEVER ( SCARLATINA)
63
● Susceptibility test: (Erythrogenic Toxin Test) positive result shows erythema or redness of the skin
Scarlet fever
DICK’S TEST
64
Diagnostic Test:
(Anti-Erythrogenic Toxin Test)
positive result exhibits a BLANCHING PHENOMENON
Scarlet fever
SCHULTZ -
CHARLTON TEST
65
It is a contagious infection of
subcutaneous skin tissue that
is characterized by redness and
edema
Cellulitis
66
Acute infection of the dermal
layer of the skin with painful
swollen, reddish spot
Erysipelas
67
A skin infection that is caused
by a group A streptococcus
that may lead to necrotizing
fasciitis, which is also known as…
Impetigo
GALLOPING GANGRENE or FLESH EATING BACTERIA SYNDROME
68
● Characterized by fever, inflammation of the heart, joints and blood vessels
● Complication of PHARYNGITIS
RHEUMATIC HEART FEVER
69
A.K.A BRIGHT’S DISEASE
ACUTE GLOMERULONEPHRITIS
70
A.K.A BRIGHT’S DISEASE
ACUTE GLOMERULONEPHRITIS
71
Inflammatory disease of the renal glomeruli
Deposition of antigen-antibody
complex to the kidneys
ACUTE GLOMERULONEPHRITIS
72
Whole organ shuts down and
leads to death
STREPTOCOCCAL TOXIC SHOCK SYNDROME
73
GROUP A (LABORATORY TESTS)
BACITRACIN DISK TEST/ TAXO A
(0.04 units)
SULFAMETHOXAZOLE AND TRIMETHOPRIM TEST (SXT)
Pyrrolidonyl Arylamidase (PYR) test
74
● Differentiates S. pyogenes from other beta-hemolytic groups
● helpful in identifying group A
in throat cultures
BACITRACIN DISK TEST/ TAXO A
(0.04 units)
75
are also susceptible to Bacitracin
Groups C and G
76
● Group ____ are also resistant SXT
● Group___ are sensitive (Not so
important)
● (+) RESULT: Exhibits Resistance
SULFAMETHOXAZOLE AND TRIMETHOPRIM TEST (SXT)
B
C
77
● More specific than bacitracin
● Detects the presence of PYR
enzyme
● (+) RESULT:____
Pyrrolidonyl Arylamidase (PYR) test
Cherry Red Color
78
● These are part of the indigenous microbiota of the female genital tract and lower gastrointestinal tract
GROUP B – STREPTOCOCCI
79
● NOSOCOMIALL Y transmitted by unwashed hands of a mother or health care personally to the newborn or infant
GBS
80
● Causes infection on the fetus during the passage through the colonized birth canal and premature rupture of mother’s membranes
GBS
81
● Species for GBS group:
Streptococcus agalactiae
82
● As for the recommendation of CDC, all pregnant women should be screened for group B streptococci…
35 - 37 weeks of gestation
83
GBS RELATED INFECTIONS:
➔ Neonatal meningitis and sepsis
➔ Pneumonia
➔ Postpartum infection
➔ Urinary Tract Infection
➔ Endocarditis
84
GROUP B (LABORATORY TESTS)
CAMP TEST (Christie-Atkins-Munch-Petersen)
HIPPURATE HYDROLYSIS TEST
85
- Used to detect B-hemolysis
● Used to differentiate S. agalactiae from other beta-hemolytic streptococci
● Culture medium is____
●___ is for the reinforcement
of the reaction
CAMP TEST (Christie-Atkins-Munch-Petersen)
BAP
SAU
86
CAMP TEST
Reagent:
beta-lysin strip or beta-lysin
producing strain of SAU
87
● It is used to differentiate S. agalactiae from other beta-hemolytic streptococci
● S. agalactiae possesses the enzyme HIPPURICASE or HIPPURATE HYDROLASE
HIPPURATE HYDROLYSIS TEST
88
○ Breaks down sodium hippurate into…
benzoic acid and glycine
89
Hippurate Hydrolysis
Reagents:
Sodium Hippurate and
Ninhydrin (Purple Color)
90
CAMP TEST RESULT
(+) RESULT:
ARROWHEAD or BOW TIE SHAPED BETA HEMOLYSIS NEAR S. aureus growth
91
HIPPURATE HYDROL YSIS TEST
(+) RESULT:
(-) RESULT:
Purple color after adding ninhydrin
No Color Change
92
● They are also known as ALPHA PRIME
STREPTOCOCCI that lack the Lancefield antigens
○ Expected colonies are MUCOID
VIRIDANS STREPTOCOCCI
93
VIRIDANS STREPTOCOCCI
● They are the most common cause of
Subacute
Bacterial Endocarditis
94
Viridans
VIRULENCE FACTORS:
Capsule
cytolysin
extracellular dextran and adhesins
95
Viridans
LABORATORY RESULTS:
Bile insoluble
optochin-resistant (TAXO P)
does not grow in 6.5% NaCl
(+) LAP
(-) PYR
96
STREPTOCOCCUS VIRIDANS:
● S. anginosus
● S. mitis
● S. sanguinis
● S. salivarius
● S. mutans
97
VIRIDANS (LABORATORY TESTS)
● _____ is peptidase that hydrolyzes peptide bonds that are adjacent to a free amino group
LEUCINE AMINOPEPTIDASE (LAP) Test
98
LAP Test
○ Substrate:
○ Reagent:
○ End product:
Leucine-B-naphthylamide
p-dimethylaminocinnamaldehyde
(DMACA)
B-naphthylamine
99
(-) LAP:
Acrococcus and Leuconostoc
100
STREPTOCOCCUS PNEUMONIAE
● Also known as
diplococcus or pneumococcus
101
● Asymptomatic member of normal respiratory tract
● Causative agent of LUMBAR PNEUMONIAE
S. pneumoniae
102
● Most common cause of bacterial pneumonia in elderly and immunocompromised individuals.
S. pneumoniae
103
● Its cell wall contains an antigen that is referred to as______ which is not related to the C carbohydrate of the various lancefield groups
C SUBSTANCE
Pneumoniae
104
Pneumoniae
Principal Virulence Factor:
Microscopy:
______ SPUTUM indicates S. pneumoniae infection
CAPSULE (Polysaccharide)
Gram (+) cocci in pairs that are oval or lancet shaped
RUSTY-TINGED
105
STREPTOCOCCUS PNEUMONIAE (LABORATORY TESTS)
NEUFELD -QUELLUNG TEST (CAPSULAR SWELLING TEST)
FRANCIS SKIN TEST
COAGULATION TEST
106
● Allows the detection of S.
pneumoniae and serotyping
isolates
● The underlying principle is that
the capsule swells in the presence of specific anticapsular serum
NEUFELD - QUELLUNG TEST
(CAPSULAR SWELLING TEST)
107
● This test is used to detect the
presence of antibodies against
the pneumococci
FRANCIS SKIN TEST
108
● It uses the particle-bound
antibody to enhance the
visibility of the agglutination
reaction between the antigen
and antibody
COAGULATION TEST
109
ENTEROCOCCI
● They are formerly known as_____
because all the species produce the group D antigen
● The species are indigenous microbiota of human and animal…
group D enterococci
intestinal tracts
110
● NOT HIGHLY PATHOGENIC but are frequent cause of nosocomial infections
● They are RESISTANT to multiple antimicrobial agents
ENTEROCOCCI
111
Enterococci
The most common isolate:
Enterococcus faecalis
112
Enterococci
RELATED INFECTIONS:
➔ UTI
➔ Endocarditis
➔ Bacteremia
➔ Wound infection
113
Enterococci
LABORATORY TESTS:
(+) Bile esculin
PYR (+) growth in 6.5% NaC
