(Lecture) Streptococcus and Enterococcus Flashcards
Streptococcus and Enterococcus spp. belong to the family _____
Streptococcaceae
A _____ results differentiate Streptococci and Enterococci from Staphylococci.
Negative Catalase Test
Streptococcus and Enterococcus have poor growth on Nutrient Media such as _____
Trypticase Soy Agar
Lancefield Classification was developed by _____
Rebecca Lancefield
What is the Basis of Classification for Academic/Bergy:
Temperature
What is the Basis of Classification for Smith and Brown:
Hemolysis
What is the Basis of Classification for Lancefield:
Serological (C-Carb of the Cell Wall)
Members on the Academic/Bergy Classification:
Pyogenic
Viridance
Entero
Lactic
Members on the Smith and Brown Classification:
Alpha
Beta
Gamma
Members on the Lancefield Classification:
Groups A-G
Partialization of the RBCs results in a greenish discoloration of the area surrounding the colony and it is termed as the _____
Alpha-Hemolysis
Streptococci producing α-hemolysis are also known as _____
Viridans Streptococci
When lysis of the red blood cells in the agar surrounding the colony is complete, the resulting area is clear this is termed as the _____
Beta-hemolysis
When the red blood cells immediately surrounding the colony are unaffected the bacteria are described as the _____ also known as the _____
Non-hemolytic
Gamma Hemolytic
Color around the colonies of the Alpha-hemolysis:
Green
Color around the colonies of the Beta-hemolysis:
Clear
Color around the colonies of the Gamma Hemolysis:
reD
Member/s that can be found under Alpha-hemolysis:
S. pneumoniae
Member/s that can be found under Beta-hemolysis:
S. equisimilis
S. pyogenes
S. agalactiae
E. faealis
Member/s that can be found under Beta-hemolysis:
Some Viridans group
Member/s of the Group A Lancefield Classification:
S. pyogenes
Member/s of the Group B Lancefield Classification:
S. agalactiae
Member/s of the Group C Lancefield Classification:
S. equisimilis
S. equi
S. dysogalactiae
S. zoopidimidus
Member/s of the Group D Lancefield Classification:
A. Enterococci
- E. faecalis
- E. faecium
- E. avium
- E. durans
B. Non-Enterococci
- S. bovis
- S. equinus
Pyogenic group does not grow at _____ compared with the viridans group that can grow at that interest temperature.
45°C
Pyogenic and viridans group does not grow under _____ but grows best at _____
10°C
37°C
_____ group grows at all temperatures
Entero
Lactic group grows best at _____ and _____, but does not grow at _____
10°C
37°C
45°C
All of the streptococci grows best at optimum temperature of _____
37°C
The best defined virulence factor is Streptococcus pyogenes is the _____ encoded by the genes emm
M protein
The best defined virulence factor is streptococcus pyogenes is the M protein encoded by the _____
Genes emm
A hemolysin that is highly immunogenic; measured using ASO (antistreptolysin O) test and is oxygen labile
Streptolysin O
A hemolysin that is nonimmunogenic and have a stable oxygen
Streptolysin S
A toxin that causes Scarlet Fever
Streptococcal Pyrogenic Exotoxin
Streptococcal Pyrogenic Exotoxin is also called _____
Erythrogenic Toxin
A toxin that causes Acute Glomerulonephritis
Nephrogenic Toxin
Streptococcal Pyrogenic Exotoxin causes _____
Scarlet Fever
Nephrogenic Toxin causes _____
Acute Glomerulonephritis
The four immunologically distinct exotoxin types found in Streptococcus pyogenes are the:
SpeA
SpeB
SpeC
SpeF
Identify the Virulence Factor:
- Spreading factors localized in the skin
- An important Streptococcus factor which has a critical role in the pathogenesis of invasive Streptococcal diseases
Streptokinase
An enzyme that solubilizes the ground substance of mammalian connective tissue which is hyaluronic acid.
Hyalurodinase
Virulence Factor that acts as an adhesion molecule
Lipoteichoic Acid and Protein F
Additional molecules that mediate attachment to host epithelial cells
Lipoteichoic Acid and Protein F
Identify the Virulence Factor bases on the characteristics given:
- Produced by S. agalactiae
- Heat stable protein
- Enhances the beta-hemolysis of S. aureus
CAMP Factor
Gram Stain Morphology of Streptococcus spp.
Gram-positive cocci in pairs or chains
Cultural Characteristics of Streptococcus spp.
Pinpoint Colonies
Identify the Specie based on its Cultural Characteristics:
Small, transparent and smooth; beta-hemolytic; when grows in sheep’s blood agar
S. pyogenes
Identify the Specie based on its Cultural Characteristics:
Grayish white mucoid colonies; beta-hemolytic (small zone)
S. agalactiae
Test result of Streptococcus spp on Catalase Test:
Negative Catalase Test; no bubble formation
A test that differentiates Group A Streptococci from other Streptococci
Bacitracin Susceptibility Test (Taxo A)
What specie/s is positive for Bacitracin Susceptibility Test (Taxo A)?
Group A Strep
What specie/s is negative for Bacitracin Susceptibility Test (Taxo A)?
Other Beta-hemolytic Streptococci spp.
A test that is helpful in screening for Group A Streptococcus in throat cultures
Bacitracin Susceptibility Test (Taxo A)
This test is used to differentiate Streptococcus agalactiae from other Streptococcal species
CAMP Test
“CAMP” in CAMP Test means _____
Christie, Atkins, Munch, and Petersen
CAMP is an acronym for Christie, Atkins, and Munch-Petersen which was identified in _____
1944
Positive test result in CAMP Test shows:
Arrowhead hemolysis [Group B Strep] or bowtie appearance [S. agalactiae]
Positive color result in PYR Hydrolysis Test:
Cherry Red/Pink
Test for Group A and Group D Streptococci
PYR Hydrolysis Test
Substrate in PYR Hydrolysis Test:
L-pyrrolidonyl-beta-napthylamide
Reagent used in PYR Hydrolysis Test:
p-dimethyl-aminocinnamaldehyde
Enzyme in PYR Hydrolysis Test:
pyrroglutamylamino peptidase or pyrrolidomylaryl amidase
The only species of Streptococcus that is PYR positive.
Streptococcus pyogenes
Medium for Hippurate Test:
Broth with hippurate
Reagent indicator for Hippurate Test:
Ninhydrin
Positive color on Hippurate Test:
Purple (S. agalactiae)
A test that differentiate Group D from Beta-hemolytic.
Bile Esculin Test
Enzyme in Bile Esculin Test
Esculinase
Positive test result in Bile Esculin Test
Blackening of medium [Group D]
Further test from Bile Esculin Test
Salt Tolerance Test (6.5% NaCl)
A test that is used in the identification of enterococcal group D streptococcus on the basis of their salt tolerance.
Salt Tolerance Test (6.5% NaCl)
Negative result in Salt Tolerance Test (6.5% NaCl)
Clear/Transparent [Non-enterococci]
Positive result in Salt Tolerance Test (6.5% NaCl)
Turbid [Enterococci]
Substrate in Leucine Aminopeptidase Test
Leucine-β-naphthylamide
Reagent of Leucine Aminopeptidase Test
paradimethylaminocinnamaldehyde reagent
Positive color of Leucine Aminopeptidase Test
Red color
What specie/s is positive in Leucine Aminopeptidase Test?
Viridans Streptococci
The substrate leucine-beta-naphthylamide is hydrolyzed to _____ after the addition of
paradimethylaminocinnamaldehyde reagent
β-naphthylamine
The substrate leucine-beta-naphthylamide is hydrolyzed to β-naphthylamine after the addition of _____
paradimethylaminocinnamaldehyde reagent
Test that is in conjunction with bacitracin is used for the presumptive identification of beta hemolytic streptococci on blood agar.
SXT or Sulfamethoxazole Susceptibility Test
What specie/s is resistant on SXT or Sulfamethoxazole Susceptibility Test?
Group A & B Strep
What specie/s is susceptible on SXT or Sulfamethoxazole Susceptibility Test?
Other Strep spp.
A test that detects carbohydrate component of the cell wall of Streptococci.
Serological Tests
Principle of Streptex Test
Antigen (from colonies) - Antibody (from Reagent) Reaction
Positive result in Serological Test
Agglutination/clumping [Group A Strep]
Negative result in Serological Test
No agglutination [S. agalactiae]
A rapid latex test system for use in the qualitative detection and identification of the lancefield group of Streptococci
Serological Tests
A clinical infection that is most often seen in children between 5 and 15 years of age
Strep Throat
Strep Throat is most often seen in children between _____ and _____ of age
5
15
Incubation period of Strep Throat
1-4 Days
Strep Throat subsides within _____ to _____ days
1
5
A localized skin disease, begins as small vesicles that progress to weeping lesions; inoculation of organisms through minor abrasions or insect bites
Impetigo
Impetigo It is usually seen in children ages _____ and it affects exposed areas of the skin
2-5 years old
A pyodermal infection that is followed by deeper invasion of streptococci; life-threatening; with bacteremia or sepsis
Cellulitis
In patients with peripheral vascular disease or diabetes, cellulitis may lead to _____
Gangrene
A rare infection of the skin and subcutaneous tissues observed frequently in elderly patients
Erysipelas
Lesion characteristics of Erysipelas:
Acute spreading, intensely erythematous with plainly demarcated but irregular edge
A pyodermal infection that is characterized by a diffuse red rash on upper chest and spreads to the trunk and extremities.
Scarlet Fever
An invasive infection characterized by rapidly progressing inflammation and necrosis of the skin, subcutaneous fat, and fascia
Necrotizing Fasciitis
Necrotizing Fasciitis’ other terms:
“Flesh-eating disease or syndrome”
“Suppurative fasciitis”
“Hospital gangrene”
“Necrotizing erysipelas”
A condition in which the entire organ system collapses, leading to death. Portal of infection is unknown, although minor injuries or surgeries have been implicated. This condition is caused by a type of streptococcal pyrogenic exotoxin – SpeA
Streptococcal Toxic Shock Syndrome
- Follows after S. pyogenes pharyngitis
- Characterized by fever and inflammation of the heart, joints, blood vessels and subcutaneous tissues
- Most serious result: chronic, progressive damage to the heart valves
Rheumatic Fever
- Follows after cutaneous or pharyngeal infection
- More common in children than in adults
Acute Glomerulonephritis
Group A Streptococci are (susceptible or resistant) to penicillin.
Susceptible
Group A Streptococci are susceptible to _____.
Penicillin
If a patient is infected with Group A Streptococcal and is susceptible for penicillin, what drugs of choice can be used?
Erythromycin
What Streptococcus specie is the significant cause of invasive disease in newborn
Streptococcus Agalactiae
What are the two clinical syndromes that are associated with neonatal GBS disease:
- Early-onset infection (<7 days old)
- Late-onset infection (at least 7 days old to about 3 months old)
Early onset infection gives what type of neonatal GBS disease/s?
Pneumonia and Sepsis
Late-onset infection gives what type of neonatal GBS disease/s?
Meningitis and Sepsis
Samples collected from pregnant women that will be screen for GBS should be inoculated into a selective broth _____ containing 10 microgram per ml of colistin and 15 microgram ml of nalidixic acid
Todd-Hewith Broth
How many ml of colistin and nalidixic acid does a Todd-Hewith Broth have?
10 microgram per ml of colistin
15 microgram ml of nalidixic acid
The drug of choice for treating GBS infection is _____
Penicillin
Some clinicians recommend a combination of _____ and a _____ for treating GBS infection.
Ampicillin
Aminoglycoside
Subdivisions of Group C and G Streptococci:
- Large-colony Forms
- Small-colony Forms
Streptococcus pneumoniae is also known as _____ or _____
Pneumococcus or Diplococcus
Streptococcus pneumoniae is a member of _____ group
S. mitis group
Antigen present in the cell wall of Streptococcus pneumoniae
C substance
A beta-globulin in human serum
C-reactive protein (CRP)
Hemolysis pattern of Streptococcus pneumoniae:
Alpha-hemolytic
Predisposing factors of Streptococcus pneumoniae:
- Alcoholism
- Anesthesia
- Malnutrition
- Viral infections of the upper respiratory tract
The vaccine that has been successful in reducing the incidence and severity of pneumococcal disease
Heptavalent pneumococcal conjugate vaccine (PCV7)
Gram Stain morphology of Streptococcus pneumoniae:
- Gram-positive cocci in pairs (diplococci)
- The ends of the cells are slightly pointed (oval or lancet shape)
Appearance of Young Cultures of Streptococcus pneumoniae:
Round, glistening, wet, mucoid, dome-shaped appearance
Appearance of Old Cultures of Streptococcus pneumoniae:
Coin with a raised rim appearance
The more commonly used procedure in order to differentiate Streptococcus pneumoniae from the Viridans streptococci
Optochin susceptibility
In between Pneumococci and Viridans Streptococci, who is susceptible and who is resistant in optochin test?
Suseptible: Pneumococci
Resistant: Viridans Streptococci
A test that determines the lysis of streptococcus pneumoniae in the presence of the bile salts.
Bile Solubility Test
Indicator in Inulin Fermentation:
Phenol Red
In between Pneumococci and Viridans Streptococci, who is positive and negative in Inulin Fermentation Test?
Positive: Streptococcus pneumoniae
Negative: Viridans Group
Color of a positive result Inulin Fermentation
Yellow
Color of a negative result in Inulin Fermentation Test
Pink or Red
The Capsular Swelling Reaction also known as the _____
Nueffeld Quellung Reaction
Positive result in the Capsular Swelling Reaction or Neufeld Quellung Reaction:
- Obvious capsule
- S. pneumoniae
Negative result in the Capsular Swelling Reaction or Neufeld Quellung Reaction:
- No capsule
- All other Alpha hemolytic Streptococci
A German microbiologist who identified several flames of the bacterium streptococcus pneumoniae, one of which was virulent and caused death when injected into mice and another which was non-virulent and did not cause illness when injected into mice.
Fred Neufeld
Positive result in the Mouse Virulence Test:
Death of Test Animal
The test for the previous infection of Streptococcus pneumoniae and a positive result is induriation or wheale formation in the skin
Francis Skin Test
Positive result in the Francis Skin Test:
Induration or Wheale formation
Drug of choice for the treatment of Streptococcus pneumoniae:
Penicillin
If a patient that is infected with Streptococcus pneumoniae is Penicillin resistant, what drug/s is used for treatment?
Erythromycin or Chloramphenicol
“Viridans” means _____
“Green”
Species under the S. mitis group:
S. mitis
S. Pneumoniae
S. sanguis
S. oralis
Species under the S. mutans group:
S. mutans
S. sobrinus
Species under the S. salivarus group:
S. salivarus
S. vestibularis
Species under the S. bovis group:
S. equinus
S. gallolyticus
S. infantarius
S. alactolyticus
Species under the S. anginosus group:
S. anginosus
S. constellatus
S. intermedius
S. constellatus subsp. pharyngis produces what disease?
Pharyngitis
Group D Streptococci is subdivided into two groups. What are the two groups?
- Enterococci
- Non-enterococci
Tests that differentiate the two groups of Group D Streptococci:
- PYR Test
- 6.5% NaCl Test
In between the two groups of Group D Streptococci, who is positive and negative in the PYR Test?
Positive: Enterococci
Negative: Non Enterococci (Group D Streptococci)
In between the two groups of Group D Streptococci, who is positive and negative in the 6.5% NaCl Test?
Positive: Enterococci (growth)
Negative: Non-enterococci (no growth)
In between the two groups of Group D Streptococci, who is resistant and susceptible in Penicillin Resistance Test?
Resistant: Enterococci
Susceptible: Group D Streptococci (Nonenterococci)
Common species under Enterococcus group:
E. faecalis
E. faecium
Enterococcus Group have the ability to grow under extreme conditions. What are the factors that make the Enterococcus Group to grow in extreme conditions?
- Presence of bile
- 6.5% NaCl or alkaline pH
- 45 degree Celsius
An Enterococci clinical infection from receiving hemodialysis, immunocompromised patients with a serious underlying disease, prior surgical procedure
Bacteremia
An Enterococci clinical infection from elderly patients with prosthetic valves or valvular heart disease
Endocarditis