Chapter 14: Streptococci, Enterococci and Related Genera Flashcards
1
Q
How does Streptococci being classified?
A
- Colony morphology and hemolytic reactions on blood agar
- Serologic specificity of the cell wall group-specific substance
- Biochemical reactions and resistance to physical and chemical factors
- Ecologic features
2
Q
Complete disruption of erythrocytes with clearing of the blood around the bacterial growth
A
B-hemolysis
3
Q
Incomplete lysis of erythrocytes with reduction pf hemoglobin and the formation of green pigment
A
a-hemolysis
4
Q
Group A pyogenic Streptococci
B hemolysis
A
Streptococcus pyogenes
5
Q
Group B pyogenic Streptococci
B hemolysis
A
Streptococcus agalactiae
6
Q
Group C, G pyogenic Streptococci
B hemolysis (human infections)
A hemolysis
A
Streptococcus dysgalactiae
Subspecies: Equisimilis
7
Q
Group D Viridans Streptococci with no hemolysis
A
Streptococci bovis group
8
Q
Group F Viridans Streptococci
a hemolysis
A
Streptococcus anginosus group
9
Q
Group A Viridans Streptococci
A
Streptococcus anginosus
10
Q
Group C Viridans Streptococci
A
Streptococcus intermedius
11
Q
Group G Viridans Streptococci
A
Streptococcus constellatus
12
Q
No group specific substance but they are a hemolytic
A
Mutans group
Streptococcus mutans
13
Q
Mitis-Sanguinis group with a hemolysis
A
Streptococcus pneumoniae
Streptococcus mitis
Salivarius group
14
Q
Pyogenic Streptococci that has inhibited by bacitracin
A
Streptococcus pyogenes
15
Q
Pyogenic Streptococci that positive in hippurate hydrolysis and CAMP-factor positive
A
Streptococcus agalactiae
16
Q
Grow in the presence of bile, hydrolyze esculin, no growth in 6.5% NaCl, degrades starch
A
Streptococcus bovis
17
Q
Group A Viridans Streptococci that is bacitracin resistant and PYR negative
A
Streptococcus anginosus
18
Q
All Viridans Streptococci are Voges Proskauer (VP) positive except?
A
Mitis group
19
Q
Mitis-sanguinis group that is susceptible to optochin
A
Streptococcus pneumoniae
20
Q
Mitis-Sanguinis group that has high-level resistance to penicillin
A
Streptococcus mitis
21
Q
The serologic specificity of the group-specific carbohydrate is determined by?
A
An amino sugar
22
Q
Serologic specificity sugar for group A Streptococci.
A
Rhamnose-N-acetylglucosamine
23
Q
Serologic specificity sugar for group B Streptococci.
A
Rhamnose-glucosamine polysaccharide
24
Q
Serologic specificity sugar for group C Streptococci.
A
Rhamnose-N-acetylgalactosamine
25
Serologic specificity sugar for group D Streptococci
Glycerol teichoic acid containing D-alanine and glucose
26
Serologic specificity sugar for group F Streptococci.
Glucopyranosyl-N-acetylgalactosamine
27
For grouping Streptococci, what are the extraction methods prepared to determine their group-specific antigen
1. Centrifuged culture treated with
Hot hydrochloric acid
Nitrous acid
Formamide
2. Enzymatic lysis with streptococcal cells with
pepsin and trypsin
3. Autoclaving of cell suspensions
28
Antigenic specificity of the capsular polysaccharide is used to classify
Streptococcus pneumoniae
29
Main human pathogen associated with local or systemic invasion and poststreptococcal immunologic disorders
Streptococcus pyogenes
30
Gram stain of Streptococci
Positive
31
Capsules of group A Streptococci are composed of?
Hyaluronic Acid
32
How does the capsule of S.pyogenes causes virulence?
By binding to hyaluronic-acid-binding protein, CD44 that are present on human epithelial cells that induce disruption of intercellular junctions
33
present in the cell wall of Streptococcus pyogenes
Proteins (M,T,R antigens)
Carbohydrates (group specific)
Peptidoglycans
34
Composition of pili of Streptococcus pyogenes
M proteins covered with lipoteichoic acid
35
Responsible for the attachment of Streptococci to the epithelial cells
Lipoteichoic acid
36
Most Streptococci grow in solid media as?
1-2 mm discoid colonies
37
Growth of Streptococci are poor on solid media or broth unless enriched with?
Blood or Tissue fluids
38
Growth and hemolysis of Streptococci are aided by
incubation in 10% CO
39
Pathogenic hemolytic streptococci grow best at temperature
37 degrees Celcius
40
Most Streptococci are __________ anaerobes
Facultative
41
Colonies of Streptococci pyogenes that has many M proteins and are virulent
Matte colonies
42
Colonies of Streptococci pyogenes that produce little M protein and not virulent.
Glossy colonies
43
Major virulence factor of S. pyogenes
M protein
44
How does M protein contributes to the virulence of S. pyogenes?
Resist phagocytosis
| Inhibits activation of alternate C pathway
45
Class of M protein of S.pyogenes that react with human cardiac muscle and the virulence determinant for rheumatic fever
Class 1 M protein
46
Toxins and enzymes exhibited by S.pyogenes
```
Streptokinase
Deoxyribonucleases
Hyaluronidase
Hemolysins
Erythrogenic Toxin
```
47
Enzyme of S.pyogenes that transforms plasminogen to plasmin allowing them to escape from blood clots
Streptokinase (Fibrolysin)
48
Enzymes that facilitate the spread of Streptococci in tissue by liquefying pus
Deoxyribonucleases (A,B,C,D) degrade DNAses
49
How does the enzymatic activity of DNAses can be measured in DNA solutions?
Decrease in viscosity
50
Enzymes used in enzymatic debridement that liquefies exudates and facilitates removal of pus and necrotic tissue
Streptokinase & DNAses
51
Enzyme that aid in spreading infecting microorganism (spreading factor)
Hyaluronidase
52
Pyrogenic exotoxin of S.pyogenes that carry lysogenic phage
Spe A (most widely studied)
53
Pyrogenic exotoxin of S.pyogenes that contributes to the streptococcal toxic shock syndrome and encoded in phage
Spe C
54
Pyrogenic exotoxin of S.pyogenes that is a potent protease that interferes with phagocytosis
Spe B
55
The group A Streptococci associated with toxic shock syndrome are primarily of M protien types?
Types 1 & 3
56
How does pyrogenic exotoxins causes toxic shock syndrome?
They act as superantigens that binds to MHC II in the Vb region of T-cell and activates them and release of cytokines mediates the shock
57
Hemolysins that is hemolytically active in reduced state and inactivated in the presence of oxygen
Streptolysin O
58
Antibody that appears in human after infection of any Streptococci that produce streptolysin O
Anti-streptolysin O (ASO)
59
Units in ASO titer that indicates recent infection of S.pyogenes
160-200 units
60
Hemolysin of S.pyogenes that is responsible for the hemolytic zones around streptococcal colonies growing on blood agar plates
Streptolysin S
61
Diseases attributable to invasion by S.pyogenes
```
Erysipelas
Cellulitis
Necrotizing fasciitis (streptococcal gangrene)
Puerperal fever
Bacteremia or Sepsis
```
62
S.pyogenes portal of entry is the skin, that leads to raised,red lesion with edema and sharply demarcated margin of infection
Erysipelas
63
rapidly spreading infection of the skin and subcutaneous tissue caused by S.pyogenes with mild trauma, burns, wounds or surgical incisions. Not raised lesion and line between the involved and uninvolved tissue is indistinct
Cellulitis
64
Extensive and very rapidly spreading necrosis of the skin, tissues and fascia.
Necrotizing fasciitis (streptococcal gangrene)
65
S.pyogenes enter the uterus after delivery that leads to septicemia originating in the infected wound (endometritis)
Puerperal fever
66
Most common infection caused by B-hemolytic S.pyogenes
Streptococcal sore throat or pharyngitis
67
In streptococcal pharyngitis, this glycoprotein serves as lipoteichoic acid ligand.
Fibronectin
68
Local infection of superficial layers of skin in children, consists if superficial vesicles and crusty lesion
Streptococcal pyoderma
69
Invasive S. pyogenes infections characterized by shock, bacteremia, respiratory failure and multiorgan failure.
Streptococcal toxic shock syndrome
70
Group A streptococcal skin infection are often attributable to M types?
49, 57, 59, 60, 61
71
The S.pyogenes of the M types_________ make pyrogenic exotoxin A or B.
M types 1 & 3 (12 & 28)
72
Exotoxin of S. pyogenes that causes scarlet fever
Pyrogenic exotoxins A-C
73
Poststreptococcal diseases includes
Rheumatic fever
| Glomerulonephritis
74
Nephritis and rheumatic fever appears after infections of S.pyogenes during?
1-4 weeks (mean 7 days)
75
Nephritis is preceded by infection of S.pyogenes in the?
Skin
76
Rheumatic fever is preceded by infection of S.pyogenes in the?
Respiratory tract
77
How many days (mean) does acute glomerulonephritis appears after infection of S.pyogenes?
7 days
78
Strains of S. pyogenes that are nephritogenic (skin)
M types 2, 42, 49, 56, 57, 60
79
Strains of S. pyogenes that are nephritogenic (throat infections and glomerulonephritis)
M types 1, 4, 23 and 25
80
Important antigens in the glomerulonephritis
Spe B and nephritis-associated plasmin receptor
81
Most serious sequela of S.pyogenes because it results to heart muscle and valves damage.
Rheumatic fever
82
Onset of rheumatic fever preceded by S.pyogenes pharyngitis is ______
19 days earlier
83
Strains of S.pyogenes associated with rheumatic fever
M types 1, 3, 5, 6, 18
84
What are the poststreptococcal autoimmune, neuropsychiatric disorders associated with streptococci (PANDAS)
```
Fever
Malaise
Migratory nonsuppurative polyarthritis
Carditis
Sydenham’s chorea
```
85
Manifestation of acute rheumatic fever characterized by involuntary, uncoordinated movements and associated muscle weakness
Sydenham’s chorea
86
Test used to estimate rheumatic activity
Erythrocyte sedimentation rates
Serum transaminase levels
Electrocardiograms
87
Poststreptococcal that can be reactivated by recurrent streptococcal infection
Rheumatic fever
88
Patients are protected by recurrent S.pyogenes infections by what drug?
Prophylactic penicillin
89
Specimens that can be used for lab test for S.pyogenes
```
Throat swab
Pus
CSF
Sterile body fluid
Blood
Serum (antibody determinations)
```
90
S.pyogenes can be identified by rapid tests like
Test for the presence of the group A-specific antigen
| PYR Test
91
Group that has a positive result to bacitracin
Group A Streptococci (B hemolysis)
92
Antigen detection test for S.pyogenes includes
Enzyme immunoassay
| Agglutination Tests
93
More sensitive assays for detection of S.pyogenes
DNA probes
| Nucleic acid amplification
94
Most widely used serologic test for S.pyogenes, used particularly in respiratory diseases
Anti-ASO titer
95
Serologic test for skin infection caused by S.pyogenes
Anti-DNAse B
Anti-hyaluronidase
(Others include antistreptokinase, anti-M type specific antibodies)
96
Resistance against streptococcal diseases is _________ type specific.
M type specific
( A host who recovered from infection by one group A streptococcal M type is immune to reinfection by the same type but fully susceptible to infection by another M type)
97
All S. Pyogenes are susceptible to
Pen G
98
these drugs are for penicillin-allergic patients with necrotizing fasciitis
Macrolides, Erythromycin, Clindamycin
99
How many days does penicillin erythromycin results in effective tissue
10 days
100
Mode of transmission of S.pyogenes
clinical infection
subclinical infection
droplets from the respiratory tract
skin
101
Early antimicrobial therapy of respiratory and skin infections with Group A streptococci
Benzathine penicillin G (intramuscular)
102
Antistreptococcal chemophylaxis in persons who have suffered an attack of rheumatic fever
1. One injection of benzathine Pen G intramuscularly every 3-4 weeks or
2. Daily oral penicillin or oral sulfonamide
103
3rd step in the control procedures for S.pyogenes
Eradication of S. pyogenes from carriers
104
Streptococcus agalactiae are group B streptococci found normally in
Vagina
| Lower respiratory tract
105
Group B streptococcal infection during 1st month of life are
Sepsis
Meningitis
Respiratory distress syndrome
106
For those mothers who are colonized by group B streptococci, prior to labor they are given ______ (drug)
Intravenous ampicillin
107
Streptococcal groups that has hemolysins and M proteins analogous to group streptococci
Groups C & G
108
Group D streptococci that is more recently important to human disease
Streptococcus bovis
109
Group D streptococcus that has DNA Cluster I
Streptococcus equinus
110
Group D streptococcus that has biotype 1 (DNA Cluster II) where isolates ferment mannitol
Streptococcus gallolyticus
111
Biotype II, DNA cluster III group D streptococci
Streptococcus infantarius
112
Group D streptococcus biotype _____ bacteremias are associated with biliary sources.
Biotype II
113
Group D streptococcus that is DNA Cluster IV
Streptococcus alactolyticus
114
What group of streptococci that is non-hemolytic, PYR negative and grows in bile and hydrolyze esculin
Group D streptococci
115
Streptococcus that are normal in throat, colon and urogenital tract
Streptococcal anginosus group
| S. consellatus & S. intermedius
116
Streptococcus that has butterscotch or caramel odor
Streptococcus anginosus group
117
Streptococcus that causes infection in dogs
Streptococcus canis
118
Viridans streptococci is consists of
```
S. mitis group
S. anginosus group
S. mutans group
S. salivarus group
S. bovis group
```
119
Viridans streptococci are normal microbiota most prevalent in?
Upper respiratory tract
120
Viridans streptococci that synthesize dextrans & levans (large polysaccharides) present in dental caries
S.mutans
121
Nutritionally variant, deficient streptococci are
Abiotrophia
| Granulicatella
122
Requires pyridoxal or cysteine for growth on blood agar
NVS
123
Streptococci that grows only under anaerobic or microaerophilic conditions and variably produce hemolysins
Peptostreptococcus
124
Peptostreptococcus are normal microbiota in?
Mouth
Upper respiratory tract
Bowel
Female genital tract
125
gram-positive diplococci, often lancet shaped or arranged in chains with polysaccharide capsule
Streptococcus pneumococci
126
Pneumococci are normal inhabitants in?
Upper respiratory tract
| can cause pneumonia, sinusitis, otitis, bronchitis, bacteremia, meningitis, peritonitis
127
Autolysis of pneumococci is enhanced by
surface-active agents
128
On solid media, the growth of pneumococci is inhibited around a disk of?
Optochin
129
Hemolysis of pneumococci on blood agar
a-hemolysis
130
Growth of pneumococci is enhanced by
5-10% CO2.
131
Polysaccharide present in the cell wall of S.pneumoniae that can be detected in the urine and CSF
C-polysaccharide
132
Antiserum used in determination of pneumococci in fresh sputum
Polyvalent antiserum
133
Pneumococcal types responsible for adult pneumonia
Types 1-8
134
Pneumococcal types responsible for children pneumonia
Types 6, 14, 19, 23
135
Virulence of pneumococci
Capsule (prevents/delays ingestion by phagocytosis)
136
Circumstances that lowers the resistance to pneumococci
1. Viral and other respiratory tract infection
2. Alcohol/Drug Intoxication
3. Abnormal circulatory dynamics
4. Malnutrition, General Debility, Sickle-cell anemia, hyposplenism, nephrosis, complement deficiency
137
Significant complication of pneumococcal infections
Empyema (pus in the pleural space)
138
Specimen used in lab tests for pneumococci
Blood
CSF
Sputum
139
Positive stained smear of pneumococci
gram-stained film with rusty red sputum with PMN and RBCs
140
Pneumococci remain susceptible to?
Vancomycin
141
Pneumococci are resistant against
Pen G
Tetracycline
Erythromycin
Flouroquinolones
142
Prevention and control of pneumococci is thru
Vaccine
143
Current conjugate vaccine of pneumococci with diphtheria
PCV 13, Prevnar 23 (Wyeth Pharmaceuticals)
144
When does children receive pneumococcal conjugate vaccine?
Four-dose series 2,4, 6, 12, 15 months of age
145
Pneumococcal vaccine for adults 19 yrs older with immunocompromised conditions
PPSV23 & PCV13
146
group D group specific-substance, non-hemolytic, PYR positive, bile esculin positive, grew well in 6.5 NaCl
Enterococci
147
Most common cause of enterococcal infection
Enterococcus faecalis (85-90%)
148
Least common cause of enterococcal infections
Enterococcus faecium (5-10%)
149
Most frequent causes of health-care associated infections, transmitted on medical devices
Enterococcal infections
150
Most common sites of Enterococcal infections
Urinary tract
Wounds
Biliary tract
Blood
151
Enterococcus that is more antibiotic-resistant
Enterococcus faecium
152
Enterococci are resistant to?
```
Cephalosporins
Penicillinase-resistant penicillins
Monobactams
Fluoroquinolones
Aminoglycosides
```
153
Enterococci are inhibited by
B-lactams (ampicillin)
154
Treatment for severe enterococcal infections (endocarditis)
Penicillin/Vancomycin + Aminoglycoside (streptomycin/gentamicin)
155
Reason for high level aminoglycoside resistant of the enterococci
because they have aminoglycoside-modifying enzymes
156
Gene that codes aminoglycoside-modifying enzymes
conjugative plasmids
| transposons
157
Enterococci: Resistance to _____ predict resistance to other aminoglycosides EXCEPT streptomycin
Gentamicin
158
Alternative drug to a penicillin (+ aminoglycosides) for enterococcal infections
Vancomycin
159
Vancomycin resistance phenotypes: inducible high-level resistance to vancomycin and teicoplanin
Van A phenotype
160
Vancomycin resistance phenotypes: inducibly resistant to vancomycin but susceptible to teicoplanin
Van B
161
Vancomycin resistance phenotypes: intermediate to moderate resistance to vancomycin
Van C
162
Vancomycin resistance phenotypes: moderate resistance to vancomycin and low-level resistance or susceptibility to teicoplanin
Van D
163
Vancomycin resistance phenotypes: low-level resistance to vancomycin and susceptibility to teicoplanin
Van E
164
Vancomycin resistance phenotypes: isolates usually E.faecalis have low-level resistance to vancomycin and are susceptible to teicoplanin
Van L
165
Vancomycin and Teicoplanin interfere cell wall synthesis in gram positive by interacting with the?
D-alanyl-D-alanine
166
The best studied vancomycin resistance determinant
Van A operon (packed of genes in plasmid-containing transposon)
167
Genes for regulatory system and is sensitive to the presence of vancomycin/teicoplanin in the environment
Van R and Van S
168
Genes that are required for glycopeptide resistance
Van H
Van A
Van X
169
Gene that encodes dehydrogenase
Van H
170
Gene that encodes ligase
Van A
171
Gene that encodes dipeptidase that depletes the normal d-Ala-d-Ala dipeptide
Van X
172
Gene that encodes carboxypeptide that cleaves the terminal d-Ala from the pentapeptide, depleting the environment of any functional pentapeptide
Van Y
173
Treatment for vancomycin-resistant enterococci
Daptomycin
Linezolid
Quinupritis-dalfopristin
Tigecycline
174
genera that catalase-negative, gram-positive cocci that is vancomycin resistant
Pediococcus
| Leuconostoc
175
Lactobacilli are _____ resistant
Vancomycin-resistant
176
Catalase-negative, gram positive cocci that are vancomycin-susceptible
Lactococcus
Aerococcus
Gemella
177
Catalase-negative that is previously considered as Staphylococcus
Rothia mucilaginosa
