BACTE LEC STREP Flashcards
(118 cards)
1
Q
Streptococcus and Enterococcus spp. are usually ___________________ and __________________ cocci
A
Catalase-negative, and gram-positive cocci
2
Q
The streptococcal cells are more likely to appear in chains when grown in __________________
A
broth cultures.
3
Q
Most members of the genera Streptococcus and
Enterococcus behave like ________________________
A
facultative anaerobes.
4
Q
Classifications of Streptococci
A
Bergey’s Academic Classification
Brown and Smith Classification
Lancefield Classification
5
Q
classification based on physiologic divisions of Streptococcus
A
Bergey’s Academic Classification
6
Q
Grows neither 45 deg C nor 10 degC but
grows at 11-44 deg C; ave. 37deg C
A
PYOGENIC
7
Q
Examples of PYOGENIC
A
Streptococcus pyogenes
8
Q
Grows at 45 deg C but not at 10 deg C
A
VIRIDIANS
9
Q
Examples of VIRIDIANS
A
S. salivarius, S. mutans,S.
sanguis; S. anginosus, S.mutans
10
Q
Grows at both 45deg C and 10deg C
A
ENTEROCOCCI
11
Q
Examples of ENTEROCOCCI
A
Streptococcus faecalis
12
Q
Grows at 10deg C but not at 45deg C
A
LACTIC
13
Q
Examples of LACTIC
A
S. cremoris; S. lactis (agent of souring of milk/rancid)
14
Q
Classification based on the presence of serologically active C- CHO polysaccharide
A
Lancefield’s Classification
15
Q
Carbohydrate cell wall antigen composition of Group A and C in Lancefield Classification
A
rhamnose-N-acetylglucosamine
16
Q
Carbohydrate cell wall antigen composition of Group B in Lancefield Classification
A
rhamnose-glucosamine polysaccharide
17
Q
Carbohydrate cell wall antigen composition of Group D in Lancefield Classification
A
Glycerol teichoic acid containing alanine & glucose
18
Q
Carbohydrate cell wall antigen composition of Group F in Lancefield Classification
A
glucopyrasonyl -N-acetylgalactosamine
19
Q
Classification Based on hemolytic reaction of Streptococci on Blood Agar Plate
A
Smith and Brown Classification
20
Q
Partial hemolysis of RBC; accompanied by
a greenish discoloration
A
ALPHA
21
Q
example for ALPHA classification
A
S. pneumoniae;
S. viridans
22
Q
Complete hemolysis of RBCs indicated by
a clear colorless zone of hemolysis
surrounding the colonies
A
BETA
23
Q
example for BETA classification
A
S. Pyogenes
S. agalactiae
24
Q
Non-hemolytic or indifferent
Streptococci. No hemolysis on RBCs
A
GAMMA
25
example for GAMMA classification
S. faecalis
26
has a cell wall structure similar to
that of other streptococci and gram-positive
bacteria.
S. pyogenes
27
Resist phagocytosis (resistance to infection) and
plays a role in adherence of the bacterial cell to
mucosal cells
M protein
28
VIRULENCE FACTORS OF Streptococcus pyogenes
-M protein
-Lipoteichoic acid
-Fibronectin binding protein
-Hyaluronic acid capsule
-Streptolysin O
-Streptolysin S
-Streptococcal pyrogenic exotoxins
29
most common
serotype seen in pharyngitis.
M1 serotype
30
More than ___ different serotypes of M protein
exist
80
31
mediate attachment
to host epithelial cells.
Adhesion molecules
32
affixed to proteins on
the bacterial surface, in concert with M proteins
Lipoteichoic acid
33
secures the attachment of streptococci to the oral mucosal cells.
Fibronectin binding protein
34
prevents opsonized phagocytosis by neutrophils or macrophages
Hyaluronic Acid Capsule
35
allows the bacterium to mask
its antigens and remain unrecognized by its
host.
Hyaluronic Acid Capsule
36
responsible for hemolysis on SBA
plates incubated anaerobically
Streptolysin O
37
The O in Streptolysin O refers to this hemolysin being __________________
oxygen labile
38
___________________ is highly immunogenic and infected individuals readily form antibodies to the hemolysin
Streptolysin O
39
Streptolysin O antibodies can be measured in the
_____________________
antistreptolysin O (ASO) test
40
test to determine whether
an individual has had a recent infection with S.
pyogenes.
antistreptolysin O (ASO) test
41
is oxygen stable, lyses
leukocytes, and is nonimmunogenic.
Streptolysin S
42
The hemolysis seen around colonies that have
been incubated aerobically is due to _____________________
streptolysin S.
43
Some strains of S. pyogenes cause a red spreading
rash, referred to as _______________________
scarlet fever
44
The most common clinical
manifestations of GAS infection
Bacterial Pharyngitis
45
Most cases of bacterial
pharyngitis are due to _____________________
S. pyogenes.
46
is most often seen in children between 5 and
15 years of age
“Strep throat”
47
“Strep throat” incubation
1-4 days
48
- Most common cause of acute
pharyngitis
– Classic Strep throat with red swollen tonsils and pharynx
– A purulent exudate on the tonsils, high temperature, and swollen
lymph nodes
Streptococcus pyogenes
49
an invasive infection characterized by
rapidly progressing inflammation and necrosis of the skin,
subcutaneous fat, and fascia
Necrotizing Fasciitis
50
is a condition in which the entire organ system collapses, leading to
death.
Streptococcal Toxic Shock Syndrome
51
GAS associated with streptococcal TSS produce a streptococcal
pyrogenic exotoxin, notably _____________
SpeA.
52
typically follows S. pyogenes pharyngitis. It is characterized by fever and inflammation
of the heart, joints, blood vessels, and subcutaneous
tissues.
Rheumatic fever
53
Two serious
complications, or sequelae, of GAS disease are _____________________
(1) rheumatic fever and
(2) acute glomerulonephritis.
54
SPECIMEN COLLECTION – SITE CONSIDERATIONS of Streptococcus pyogenes
OROPHARYNGEAL SWAB
55
OROPHARYNGEAL SWAB remains moist, no further
precautions need to be taken for specimen that
are cultured within ___________of collection
4 hours
56
Streptococcus pyogenes is highly resistant to desiccation and remains viable on a dry
swab for _________________
48 to 72 hours.
57
Cultural Characteristics:
colonies are transparent to translucent, convex or domed entire,
circular, shiny and surrounded by a wide zone of β-hemolysis.
Streptococcus pyogenes
58
a presumptive test which differentiates
group A from other β-hemolytic Streptococci
Bacitracin (Taxo A)
59
any zone of inhibition regardless of the diameter is a
____reaction for Streptococcus pyogenes
(+) Positive
60
Principle of Bacitracin (Taxo A)
based on the selective inhibition of the growth of
Group A streptococci by a paper disc containing 0.02 – 0.04 units of Bacitracin
61
Detect the organisms
ability to hydrolyze the substrate
L- pyrrolidonyl-beta-napthylamide
PYR test
62
PYR test BRIGHT RED END PRODUCT
(+) Positive for Streptococcus pyogenes
63
test for susceptibility for scarlet fever
Dicks Test
64
Dicks test will be tested for reaction after ___
24 hours
65
Test to Diagnose Scarlet Fever
Schultz-Charlton Reaction (Blanching Phenomenon)
66
based on the neutralization of erythrogenic
toxins when an antitoxin is injected into the skin
of a patient with scarlet fever skin rashes fade or
blanch (+)
Schultz-Charlton Reaction (Blanching Phenomenon)
67
used to diagnose whether the skin rashes are due
to scarlet fever or not
Schultz-Charlton Reaction (Blanching Phenomenon)
68
TREATMENT for Streptococcus pyogenes
- Intramuscular benzathine penicillin as single dose
– Oral penicillin V for 10 days
– For penicillin-allergic patients – erythromycin,
clindamycin and cephalexin
69
Streptococcus agalactiae
Virulence factors
- Sialic Acid Capsule
- Hemolysin
- CAMP Factor
- Neuraminidase
- DNase
- Hyaluronidase
- Protease
70
The capsule prevents
phagocytosis
Sialic acid capsule.
71
Loss of sialic acid = _______________________
loss of virulence
72
a pore-forming protein
secreted by Streptococcus agalactiae
* CAMP Factor (proteinB)
73
contribute to the invasiveness,
cleaves the terminal N-acetylneuraminic acid
Neuraminidase
74
facilitate colonization on mucosal surfaces by degrading S-IgA
Proteases
75
_____________ are the leading cause of death in infants in the
United States.
Group B Streptococci
76
Colonization of the vagina and rectal area with.
GBS is found in _____________________ of pregnant women.
10% to 30%
77
Culture Media for Group B Streptococci: Streptococcus agalactiae
* Todd-Hewitt broth
* StrepB Carrot Broth (SCB)
78
culture media that Produced orange or red pigment even after 6 hours of incubation for GBS
StrepB Carrot Broth (SCB
79
Cultural characteristics of GBS in Sheep Blood Agar
grayish white mucoid colonies surrounded by a small zone of β-hemolysis
80
The most useful tests for GBS are positive _______________________ These tests enable the organism to be readily
differentiated from other β-hemolytic streptococcal
isolates
hippurate hydrolysis and
CAMP tests.
81
A characteristic “arrowhead” hemolytic
pattern results when the organism is streaked perpendicularly to βhemolytic S.aureus.
CAMP (Christie, Atkins, and Munch-Peterson) test
82
Positive result for GBS in Hippurate test
purple colored product
83
Streptococcus agalactiae clinical response to antimicrobial therapy is
often poor despite heavy doses given. Some
clinicians recommend a combination of ______________________for treating GBS infections.
ampicillin and aminoglycoside
84
Alpha Hemolytic Streptococcus
Streptococcus viridans
Streptococcus pneumoniae
85
3 Main Infections Caused by Viridans Streptococci
Dental Infections
Endocarditis
Abscesses
86
Streptococcus viridans groups
(1) S. mitis group (including
pneumoniae, S. sanguis, S. oralis);
(2) S. mutans group
(3) S. salivarius group
(4) S. bovis group
(5) S. anginosus group
87
is a member of the S. mitis
group, but it is much more virulent than other members of the
group
Streptococcus pneumoniae
88
S. pneumoniae can express one of approximately ___ different
capsular types
90
89
PATHOGENESIS: Invasion of the Host Tissue of Streptococcus pneumoniae
- Neuraminidase
- Autolysin
- H2O2
- Pneumonysin O
90
As the colonies become older, autolytic
changes result in the _________________
of the colony
collapse of the center
91
PATHOGENESIS: Attachment to the Host Tissue of Streptococcus pneumoniae
- Proteases
- Pili
92
facilitate colonization on
mucosal surfaces by degrading S-IgA for S. pneumoniae
Proteases
93
contribute to colonization and increase
the formation of large amounts of TNF by
the Immune system for S. pneumoniae
Pili
94
a component of the cell wall of pneumococci which is a teichoic acid that
reacts with some components of the immune response resulting in the activation of some
nonspecific host immune responses
C-substance
95
Most common
pneumonia (Lobar)
Streptococcus pneumoniae
96
specimen used for Streptococcus pneumoniae
Specimens:
blood, sputum, swabs, pus and
97
Most widely used presumptive test for
differentiating S.pneumoniae from otheralphahemolytic streptococci (
Optochin Test
98
Optochin Test Contains _____________________
ethylhydrocupreine hydrochloride
99
Optochin Test is also known as
Taxo P
100
Positive reaction is a _________ mm zone of
inhibition using a _____ mm Optochin disk.
14-16, 6
101
Equivocal reaction for S. pneumoniae
Any zone of inhibition less than 14 mm is
questionable for pneumococci
102
*S. pneumoniae produce a self-lysing enzyme to inhibit the growth
*The presence of bile salt accelerate this process
Bile Solubility Test
103
Positive and negative reaction for Bile Solubility Test
appears as clearing in the presence of bile while negative test appears as turbid
104
Based on the ability of the organism to ferment Inulin, a naturally occurring polysaccharide of plants
Inulin Fermentation Test
105
positive result for Inulin Fermentation Test
*Change of color of pH indicator and bubble/gas formation
which indicates that the sugar is fermented and acid
production results.
106
Mouse Virulence test result for Pneumococci vs Streptococci
P- dies within 16-48 hours
S- Wont die
107
Tests for differentiation of Pneumococci vs Streptococci
- Mouse Virulence Test
- Inulin Fermentation Test
- Bile solubility Test
- Optochin Test
- Neufield-Quellang Capsular Swelling Test
108
Inulin Fermentation test result for Pneumococci vs Streptococci
P- Fermenter
S- Non-fermenter
109
Bile solubility Test result for Pneumococci vs Streptococci
P- bile soluble
S- insoluble
110
Optochin Test result for Pneumococci vs Streptococci
P- Susceptible
S- resistant
111
Neufield-Quellang Capsular Swelling Test result for Pneumococci vs Streptococci
P- Swelling of capsule
S- No swelling
112
Bacterial groups in Alpha hemolytic Streptococcus
S. pneumoniae and S. viridans
113
Bacterial groups in Beta hemolytic Streptococcus
S. pyogenes and S. agalactiae
114
Bacterial groups in Gamma hemolytic Streptococcus
E. faecalis and E. faecium
115
Normal flora of the skin, upper respiratory, gastrointestinal and genitourinary tracts
Gamma-hemolytic:
Enterococci
116
Bile Esculin Test result for Enterococci vs Non-enterococci
E- (+)
NE- (+)
117
Growth w/ 6.5% NaCl Test result for Enterococci vs Non-enterococci
E- (+)
NE- (-)
118
PYR Test result for Enterococci vs Non-enterococci
E- (+)
NE- (-)
