Streptococcus and Enterococcus Flashcards
Streptococcus spp. and Enterococcus spp. belong to the family ___________.
Streptococcaceae
A characteristic which differentiates Streptococcus spp. and Enterococcus spp. from Staphylococcus spp. and Micrococcus spp.
Catalase Reaction, wherein Streptococcus spp. and Enterococcus spp. are CATALASE NEGATIVE
Describe the appearance of both Streptococcus spp. and Enterococcus spp.
- Gram (+) cocci, in pairs, and in chains (common for streptococci)
- Enterococcus spp. appears more elongated
What are the aerotolerance levels of Streptococcus spp. and Enterococcus spp.?
- Facultative Anaerobes (majority)
- Aerotolerant Anaerobes
- Capnophilic
Capnophilic species of streptococci and enterococci requires ______________.
More than 5-10% amount of CO2
TRUE OR FALSE.
Streptococcus spp. and Enterococcus spp. can ferment glucose with gas.
False (w/o gas)
Describe the colonies of Streptococcus spp. and Enterococcus spp.
Small (pinpoint) and transparent
________ of the group-specific carbohydrate is determined by an amino sugar.
Serologic Specificity
Serologic Specificity of the group-specific carbohydrate is determined by an ___________.
amino sugar
SEROLOGIC SPECIFICITY OF THE CELL WALL GROUP-SPECIFIC SUBSTANCE
Group A streptococci
Rhamnose-N-acetylglucosamine
SEROLOGIC SPECIFICITY OF THE CELL WALL GROUP-SPECIFIC SUBSTANCE
Group B streptococci
Rhamnose-glucosamine polysaccharide
SEROLOGIC SPECIFICITY OF THE CELL WALL GROUP-SPECIFIC SUBSTANCE
Group C streptococci
Rhamnose-N-acetylgalactosamine
SEROLOGIC SPECIFICITY OF THE CELL WALL GROUP-SPECIFIC SUBSTANCE
Group D streptococci
Glycerol teichoic acid containing D-alanine and glucose
SEROLOGIC SPECIFICITY OF THE CELL WALL GROUP-SPECIFIC SUBSTANCE
Group F streptococci
Glucopyranosyl-N-acetylgalactosamine
These are exotoxins which serves as a virulence factor that damages the intact RBC.
Hemolysin
Identify the Hemolytic Pattern
Description: Complete lysis of the RBCs around the colony.
Apperance: Clear area around the colony.
β-hemolytic pattern
Identify the Hemolytic Pattern
Description: No lysis of the RBCs around the colony.
Apperance: No change in agar
γ-hemolytic pattern or non-hemolytic pattern
Identify the Hemolytic Pattern
Description: Partial lysis of the RBCs around the colony.
Apperance: Greenish discoloration of area around the colony.
α-hemolytic pattern
Identify the Hemolytic Pattern
Description: Small area of intact RBCs around the colony surrounded by a wider zone of complete hemolysis.
α’-hemolytic pattern
Which hemolytic pattern is not associated with streptococci?
α’-hemolytic pattern
What was the classification scheme developed by Rebecca Lancefield?
Lancefield Classification
________ developed a classification scheme which divided streptococci into serologic groups, designated by letters.
Rebecca Lancefield
When was the Lancefield Classification developed?
1930
The Lancefield Classification is based on the __________.
C-carbohydrates
Where are C-carbohydrates found?
In the cell wall
Streptococcus pyogenes
Lancefield Group Antigen
A
Streptococcus pyogenes
Hemolysis Type
β
Streptococcus pyogenes
Common Terms
Group A streptococci
Streptococcus pyogenes
Disease(s) Associations
- Rheumatoid Fever
- Scarlet Fever
- Pharyngitis
- Glomerulonephritis
- Pyogenic Infections
Streptococcus agalactiae
Lancefield Group Antigen
B
Streptococcus agalactiae
Hemolysis Type
β
Streptococcus agalactiae
Common Terms
Group B streptococci
Streptococcus agalactiae
Disease Associations
- Neonatal sepsis
- Meningitis
- Puerperal fever
- Pyogenic infections
Streptococcus dysgalactiae and Streptococcus equi
Lancefield Group Antigen
C
Streptococcus dysgalactiae and Streptococcus equi
Hemolysis Type
β
Streptococcus dysgalactiae and Streptococcus equi
Common Terms
Group C streptococci
Streptococcus dysgalactiae and Streptococcus equi
Disease Association(s)
- Pharyngitis
- Impetigo
- Pyogenic Infections
Streptococcus bovis
Lancefield Group Antigen
D
Streptococcus bovis
Hemolysis Type
α, none
Streptococcus bovis
Common Terms
Non-enterococcus member of viridans streptococci
Streptococcus bovis
Disease Associations
- Endocarditis
- UTIs
- Pyogenic infections
Enterococcus faecalis and Enterococcus faecium
Lancefield Group Antigen
D
Enterococcus faecalis and Enterococcus faecium
Hemolysis Type
α, β, none
Enterococcus faecalis and Enterococcus faecium
Common Terms
Enterococcus
Enterococcus faecalis and Enterococcus faecium
Disease Association(s)
- UTIs
- Pyogenic infections
Streptococcus pneumoniae
Lancefield Group Antigen
None
Streptococcus pneumoniae
Hemolysis Pattern
α
Streptococcus pneumoniae
Common Terms
Pneumococcus
Streptococcus pneumoniae
Disease Association(s)
- Pneumonia
- Meningitis
- Pyogenic infections
Enumerate the different subgroups under Viridans Streptococci
MNEMONIC: BAMMSA
* Streptococcus bovis
* Streptococcus anginosus
* Streptococcus mutans
* Streptococcus mitis
* Streptococcus salivarius
Which Lancefield Group Antigen is acid-stable?
B
It is encoded by the gene “emm.”
M protein
M protein is encoded by the gene ______.
emm
How is M protein virulent?
- Resists phagocytosis
- Attach to mucosal cells
S. pyogenes is typically found in the __________.
Upper Respiratory Tract
There are ____ serotypes of M protein.
> 150 (Mahon: >80)
________ most common serotype of M protein.
M1 Protein (in pharyngitis)
Protein F is also known as ___________.
Fibronectin-binding Protein
How is Protein F and Lipoteichoic Acid virulent?
They allow the bacteria to adhere to epithelial cells
They secure the attachment of streptococci to the oral mucosal cells.
Lipoteichoic acid, together with M protein and protein F
Lipoteichoic acid, together with M protein and protein F, _______________.
secure attachment of streptococci to the oral mucosal cells
TRUE OR FALSE.
Hyaluronic Acid Capsule is weakly immunogenic.
True
How is hyaluronic acid capsule virulent?
- Impedes opsonized phagocytosis
- Allows the bacteria to mask its antigen and remain unrecognized by the host
____ is most noticeable in young cultures.
Hyaluronic Acid Capsule
Hyaluronic acid capsule is most noticeable in _________.
young cultures (18-24 hours old)
Streptolysin O (SLO)
Hemolysis on BAP
Anaerobically
Which streptolysin is anaerobic?
Streptolysin O (SLO)
Streptolysin S
Hemolysis on BAP
Aerobically
Which streptolysin is aerobic?
Streptolysin S
Streptolysin O (SLO)
Hemolysin
O hemolysin
Which hemolysin is oxygen-labile?
O hemolysin
Streptolysin S
Hemolysin
S hemolysin
Which hemolysin is oxygen stable?
S hemolysin
Streptolysin O (SLO)
Cells lysed
Leukocytes, platelets, and RBCs
Streptolysin S
Cells lysed
Leukocytes
Streptolysin O (SLO)
Immunogenicity
Highly immunogenic
Which streptolysin is highly immunogenic?
Streptolysin O (SLO)
Streptolysin S
Immunogenicity
Non-immunogenic
Which streptolysin is non-immunogenic?
Streptolysin S
Streptolysin O also serves as an __________
Antigen
Since SLO is highly immunogenic, it stimulates the host’s immune system to produce antibodies called _________.
Anti-streptolysin O antibodies
Anti-streptolysin O antibodies can be detected by ________.
Anti-streptolysin O Test
How is Deoxyribonuclease (DNAse) virulent?
- Potent protease that interferes with phagocytosis
- Contributes to the spread of streptococci by liquefying pus
TRUE OR FALSE.
DNAse is not immunogenic
False
How does DNAse contribute in the spread of streptococci?
By liquefying pus
How is Streptokinase/Fibrinolysin virulent?
They are capable of lysing fibrin clots through the action of plasminogen -> plasmin.
________ activates plasminogen for it to be converted into plasmin.
Streptokinase
The lysing of fibrin clots allow the Streptococcus pyogenes to _____________.
escape and cause infection
TRUE OR FALSE.
Streptokinase/Fibrinolysin is immunogenic.
True
But not specific to GAS, they can also be in Group C and Group G
Hyaluronidase is also known as __________.
spreading factor
__________ solubilizes the ground substance in the connective tissue.
Hyaluronidase
Streptococcal pyrogenic exotoxins are previously known as ________.
Erythrogenic Toxins
_______ causes a red spreading rash called Scarlet Fever.
Streptococcal Pyrogenic Exotoxins
The red spreading rash caused by Erythrogenic Toxins is known as _______.
Scarlet Fever
What are the four exotoxin types found in S. pyogenes?
SpeA, SpeB, SpeC, and SpeF
The most common clinical manifestation of GAS infection.
Pharyngitis and Tonsillitis
Bacterial Pharyngitis is also known as _________.
Strep Throat
Pyodermal infections lead to ______________.
Impetigo, cellulitis, erysipelas, wound infection, arthritis or scarlet fever
If the portal of entry is through the skin, it can possibly cause _______.
Erysipelas
Describe the characteristics of an Erysipelas lesion
Raised, red, massive brown edema that rapidly advances to the demarcated margin of infection
An acute rapidly spreading infection of the skin which occurs after a mild trauma, burns, wound, and etc.
Cellulitis
TRUE OR FALSE.
Cellulitis is also characterized by erythema.
True
How is the lesion in cellulitis different from the lesion in erysipelas?
- Lesion is not raised (flat)
- The line between the involved and uninvolved tissue is indistinct.
There are how many types of Necrotizing Fascitis (NF)?
3
Type 1 NF is caused by _______.
Vibrio spp.
Type 2 NF is caused by __________.
Streptococcus spp.
Commonly GAS
Type 3 NF is caused by __________.
Clostridium spp.
Necrotizing Fascitis (NF) is also known as _______.
Flesh-eating Disease
_______ is an invasive infection characterized by rapidly progressing inflammation and necrosis of the skin.
Necrotizing Fascitis (NF)
This infection involves SpeA, M1 and M3.
Streptococcal Toxic Shock Syndrome
A complication after Streptococcus pyogenes infection, wherein rheumatic fever and acute glomerulonephritis follows.
Poststreptococcal Sequelae
The common virulence factor for rheumatoid fever is _______.
Class 1 M Protein
The common virulence factor for glomerulonephritis is _________.
Class 1 and 2 M Protein
Treatment of Choice for poststreptococcal sequelae
Penicillin
It is the most commonly utilized virulence factor of S. agalactiae.
Capsule
How is the capsule of S. agalactiae virulent?
It resists phagocytosis, but is ineffective after opsonization.
What is the main component of the capsule in S. agalactiae?
Sialic Acid
These are the products of S. agalactiae, but are not considered to be virulence factors.
Hemolysin, DNAse, Neuramidase, Protease, Hyaluronidase, CAMP Factor
What is the infection acquired from S. agalactiae?
Invasive Disease of Newborn
How is the invasive disease of newborn acquired?
- Through vertical transmission (mother to offspring)
- During delivery since S. agalactiae is commonly found in the vaginal canal and rectal area
S. agalactiae is a normal flora of the _________ and _________
Vaginal canal and Rectal area
Explain the manner of specimen collection
The infection of the patient came from the upper respiratory tract. How will you get a sample of S. pyogenes?
By performing a throat swab
How is a throat swab performed properly?
By depressing the tongue and avoiding the uvula, rub a swab over the posterior pharynx and each toncillar area.
Explain the manner of specimen collection
The infection of the patient came from a pyodermal infection. Where will you get a sample of S. pyogenes?
On the patient’s wound, lesion, or pus
Explain the manner of specimen collection
The infection of the patient has been found to be systemic. Where will you get a sample of S. pyogenes?
In the CSF, blood, or bodily fluids
In collecting a specimen from exudates, it should be ________.
Touched with swab
TRUE OR FALSE.
Transport media is required in collecting S. pyogenes.
False
Not necessarily required, pero mas better daw if meron
Explain the manner of specimen collection
The patient is a pregnant woman. Where and how will you get a sample of S. agalactiae?
By performing a vaginal canal or rectal swab between 35 and 37 weeks of gestation.
Transport media for S. agalactiae specimen
- Todd-Hewitt Broth
- Lim Broth
- TransVag Broth
Todd-Hewitt Broth content
10 ug/mL colistin
Lim Broth content
15 ug/mL nalidixic acid
TransVag Broth content
8 ug/mL gentamicin and 15 ug/mL nalidixic acid
Describe the appearance of S. pyogenes and S. agalactiae when Direct Microscopic Examination is performed.
Gram (+) cocci round or oval-shaped, occassionally forming elongated cells
Which medium is used to culture S. pyogenes and S. agalactiae?
BAP (with inhibitors such as sulfamethoxazole, colistin, or polymixin B)
Which inhibitors are sometimes used in BAP when culturing S. pyogenes and S. agalactiae?
- Sulfamethoxazole (SMZ)
- Colistin
- Polymixin B
Incubation period for S. pyogenes and S. agalactiae
18 to 24 hours at 35-37 C aerobically or anaerobically
Describe the appearance of S. pyogenes colonies when performing Macroscopic Examination.
Small, transparent, and smooth with a well-defined area of β-hemolysis
Describe the appearance of S. agalactiae colonies when performing Macroscopic Examination.
Grayish-white mucoid colonies surrounded by a small zone of β-hemolysis
Which specimen?
Small, transparent, and smooth with a well-defined area of β-hemolysis
Streptococcus pyogenes
Which specimen?
Grayish-white mucoid colonies surrounded by a small zone of β-hemolysis
Streptococcus agalactiae
When the Streptococcus spp. are cultured from solid media, under microscopic examination, it appears to be ___________.
Gram (+) cocci with some short chains
When the Streptococcus spp. are cultured from broth, under microscopic examination, it appears to be ___________.
Gram (+) cocci with longer chains
Streptococcus spp. and Enterococcus spp. result in Catalase Test
Negative (-)
Which organism is positive in the Bacitracin test?
Streptococcus pyogenes
S. pyogenes is (susceptible/resistant) to the bacitracin test.
Susceptible
Which organism is negative in the Bacitracin test?
Other β-hemolytic streptococci
Which organism is positive in the Pyrrolidonyl Arylamidase test?
Streptococcus pyogenes
Which organism is negative in the Pyrrolidonyl Arylamidase test?
Other β-hemolytic streptococci
Explain the principle of Hippurate Hydrolysis Test
Principle: to determine the capability of an organism to hydrolyze hippurate.
* Hippuric Acid → glycine & benzoic acid (hippuricase will hydrolyze)
* Glycine → purple colored products (deaminated by ninhydrin reagent)
Result:
* (+) Deep purple color (S. agalactiae)
* (-) Colorless or slightly yellow pink color or tinge of purple (other β-hemolytic streptococcus
What is the positive result in Hippurate Hydrolysis Test?
Deep Purple Color
Which organism is positive in the hippurate hydrolysis test?
Streptococcus agalactiae
What is the negative result in the hippurate hydrolysis test?
Colorless or slightly yellow-pink or light purple
Hippuric acid is hydrolyzed by _________ to form glycine and benzoic acid.
hippuricase
Hippuric acid is hydrolyzed by hippuricase to form ______ and ________.
glycine and benzoic acid
Glycine is deaminated by _________ to form a deep purple colored product.
Ninhydrin reagent
Glycine is _________ by ninhydrin reagent to form a deep purple colored product.
deaminated
Explain the principle of CAMP Test
Principle: detection of diffusible extracellular protein (CAMP factor) that acts synergistically with β-hemolysin of S. aureus to cause enhanced lysis of RBCs.
* β-hemolysin – known factor; detects the presence of the other factor.
* CAMP factor – unknown factor
Result:
* (+) enhanced hemolysis indicated by an arrowhead-shaped zone of beta-hemolysis at the juncture of the two organisms (S. agalactiae)
* (-) no enhancement of hemolysis (other β-hemolytic streptococcus)
It is used to detect diffusible extracellular protein (CAMP factor) that acts synergistically with β-hemolysin of S. aureus to cause enhanced lysis of RBCs.
CAMP Test
It is the known factor in CAMP test which detects the presence of other factor.
β-hemolysin
It is the unkown factor in CAMP test.
CAMP Factor
What is the positive result in CAMP Test?
Enhanced hemolysis indicated by an arrowhead-shaped zone of beta-hemolysis at the juncture of the two organisms.
Which organism exhibits a positive result in the CAMP test?
Streptococcus agalactiae
What is the negative result in CAMP Test?
No enhancement of hemolysis
Streptococcus pneumoniae belongs to the group _________.
Viridans Streptococci
Why is S. pneumoniae under Viridans Streptococci?
They both exhibit α-hemolytic pattern
Which sub-group of Viridans Streptococci does S. pneumoniae belong?
Streptococcus mitis
Streptococcus pneumoniae is also known as ______.
Pneumococcus
TRUE OR FALSE.
Streptococcus pneumoniae has C-carbohydrate.
False
Streptococcus pneumoniae has _______.
C-substance
C-substance is found in the ________ of S. pneumoniae
cell wall
TRUE OR FALSE.
S. pneumoniae has a Lancefield Antigen Group
False
