Strep And Entero Flashcards
belong to the family Streptococcaceae
Streptococcus spp. and enterococcus spp.
Inhabit various sites, notably the upper respiratory tract, and live harmlessly as commensals.
Streptococcus and enterococcus
Both of the genera are catalase-negative (weak reaction), gram-positive cocci that are usually arranged in pairs (agar) or chains (broth)
Streptococcus and enterococcus
The cells of Enterococci and some Streptococci appear more
Elongated than spherical
Strepto and entero are Poor growth on Nutrient Media such as
Trypticase soy agar
Production of numerous exotoxins that can damage RBC under the
Smith and brown classification
The Lancefield Grouping was developed in 1930s by
Rebecca lancefield
Produces a zone of partial hemolysis with a greenish discoloration around the colonies on blood agar
Alpha-hemolytic (α) Streptococci
Streptococci producing α-hemolysis are also known as
Viridans streptococci
Produces a complete hemolysis and Sharply defined, clear, colorless zone of hemolysis around the colony induced by bacterial hemolysins
Beta (ß) Hemolytic Streptococci
No red blood cell is visible on microscopic examination in clear zone of complete hemolysis.
Beta hemolytic streptococci
constitutes the principal marker for potentially pathogenic streptococci in cultures of throat swabs or other clinical samples
Beta hemolytic streptococci
Produce no hemolysis on blood agar.
Gamma (γ) or Non-hemolytic Streptococci
What is an important organism of this group gamma or non hemolytic streptococci
Enterococcus faecalis
What is alpha color around colonies
Green
What is the members or organism of alpha
Streptococcus pneumoniae
What is the color around the colonies of beta
Clear
What is the member or organism of beta
Streptococcus equisimilis
Streptococcus pyogenes
Streptococcus Agalactiae
Enterococcus faecalis
What organisms or members are not true pathogen
Streptococcus pneumoniae
Streptococcus pyogenes
Streptococcus agalactiae
Enterococcus faecalis
What are most commonly found in lancefield grouping associated with human infections.
Group a, b, c, d, and g
What organisms are in group A
Streptococcus pyogenes
What organisms is in group B
Streptococcus agalactiae
What organism is in group C
Streptococcus equisimilis
Streptococcus equi
Streptococcus dysogalactiae
Streptococcus zoopidimidus
What organism is in group D (enterococci)
Enterococcus faecalis
Enterococcus faecium
Enterococcus avium
Enterococcus durans
What organism is in group D (non-enterococci)
Streptococcus bovis
Streptococcus equinus
part of cell wall; antiphagocytic
M protein
principal virulence factor of Group B Streptococci; antiphagocytic or prevents oxidized phagocytosis by neutrophils/macrophages
Capsule
hemolytic exotoxins
Hemolysin
hemolytic exotoxins
Hemolysin
highly immunogenic; measured using ASO (antistreptolysin O) test; responsible for hemolysis on SBA plates that are incubated anaerobically that is active in reduced form
Streptolysin O (oxygen labile)
hemolysis seen in cultures that have been incubated aerobically; non-immunogenic
Streptolysin S (oxygen stable)
What toxin causes Scarlet Fever
Streptococcal pyrogenic exotoxin/ erythrogenic toxin
is a red spreading rash
Scarlet fever
What toxin causes Acute Glomerulonephritis
Nephrogenic toxin
4 Immunologically distinct exotoxins:
SpeA
SpeB
SpeC
SpeF
spreading factors localized in the skin and important virulence factor for pathogenesis of invasive diseases
Streptokinase
spreading factors localized in the skin and enzyme that solubilizes the ground substance of mammalian connective tissues (hyaluronic acid) to separate tissue and spread infection (unsupported hypothesis)
Hyaluronidase
spreading factors localized in the skin; S. pyogenes DNases: A, B (most common), C, D
DNAse
antigenic; antibodies to DNAse can be detected after infection
DNAse
adhesion molecules that mediate attachment to host’s epithelial cells
Lipoteichoic Acid and Protein F
affects proteins on bacterial surface (along with M proteins & fibronectin binding proteins) secures attachement to oral mucosal cells
Lipoteichoic Acid
produced by S. agalactiae (group B)
CAMP Factor
diffusible, heat stable protein; enhances the beta-hemolysis of S. aureus
CAMP factor
generates a co-hemolytic reaction for identifying S. agalactiae in the lab
CAMP factor
In Gram Stain morphology
Gram-positive cocci in pairs or chains
Cultural Characteristics
Pinpoint colonies
Cultural Characteristics of streptococcus pyogenes
small, transparent and smooth; beta-hemolytic
Cultural characteristics of streptococcus agalactiae
grayish white mucoid colonies; beta-hemolytic (small zone)
determines if gram + cocci is staphylococci or streptococci
Catalase test
Presumptive identification of S. pyogenes
Bacitracin susceptibility test / taxo A
Differentiates Group A Streptococci from other Streptococci
Bacitracin susceptibility test/ taxo A
What gives positive results in bacitracin susceptibility test/ taxo A
Group a streptococcus
What gives negative result in bacitracin susceptibility test / taxo A
Other beta hemolytic streptococci spp.
Test for Group B Streptococci (S. agalactiae from other streptococcus spp.)
Christie-atkinson-munch-peterson test
What is known organism in christie-atkinson-munch-peterson
Staphylococcus aureus
Unknown organism in christie-atkinson-munch-peterson (Beta-hemolytic, catalase negative, pinpoint and bacitracin resistant)
Group B streptococci
Streptococcus agalactiae
What positive result and organism in christie-atkinson-munch-peterson
Arrow head hemolysis (group B streptococci)
Bowtie appearance (streptococcus agalactiae)
Organisms including Group B streptococci produce a diffusible extracellular hemolytic heat stable protein called
CAMP factor
Test for identifying Group A and Group D Streptococci; differentiates enterococcus spp. (PYR +) from Group D Strep
PYR hydrolysis test
What is the positive result of PYR hydrolysis test
Cherry red/pink
What is the enzymes of PYR hydrolysis test
pyrroglutamylamino peptidase or pyrrolidomylaryl amidase
What is the substrate of PYR hydrolysis test
L-pyrrolidonyl-beta-napthylamide
What is the reagent of PYR hydrolysis test
p-dimethyl-aminocinnamaldehyde
What organisms is the only PYR + strep and is susceptible to bacitracin and hydrolyzes PYR.
Streptococcus pyogenes
Differentiate Group D from Beta-hemolytic
Bile esculin test
What is the enzymes of bile esculin test
Esculinase
What is the positive result and organism of bile esculin test
Blackening of medium (group D)
Test for Group B Streptococci
Hippurate test
Test for Group B Streptococci
Hippurate test
Medium used in hippurate test
Broth with hippurate
Reagent indicator for hippurate test
Ninhydrin
What is the positive result and organism in hippurate test
Purple (streptococcus agalactiae)
What enzyme can be seen in hippurate test
Hippuricase
Further test from Bile Esculin Test
Salt Tolerance Test (6.5% NaCl)
Test used To identify Enterococci
Salt tolerance test (6.5% NaCl)
What is the positive result and organism in salt tolerance test
Turbid (enterococci)
What is the negative result and organism in salt tolerance test
Clear/transparent (non-enterococci)
Used for presumptive identification of Enterococcal group D
Salt tolerance test (6.5% NaCl)
What is the substrate of Leucine Aminopeptidase Test
Leucine-βeta -naphthylamide/ βeta-naphthylamine
What reagent used for leucine aminopeptidase test
paradimethylaminocinnamaldehyde reagent
What reagent used for leucine aminopeptidase test
paradimethylaminocinnamaldehyde reagent
What is the positive result and organism in leucine aminopeptidase test
Red color (viridans streptococci)
is used with bacitracin as presumptive identification test for B-hemolytic streptococci on Blood agars.
Sulfametoxazole susceptibility Test
What is resistant in sulfametoxazole susceptibility test
Group A&B in mixed culture
What is susceptible in sulfametoxazole susceptibility test
Other streptococcus spp. in mixed culture
Used when facilities for serologic group determination are unavailable.
Sulfametoxazole susceptibility test
Detect carbohydrate component of the cell wall of Streptococci
Serological test
What is the name of the test used in serological test
Streptex
What is the principle of serological test
Antigen (from colonies) and antibody (from reagent)
What is the positive result and organism of serological test
Agglutination/clumping (group A streptococci)
What is the negative result and organism of serological test
No clumping (streptococcus agalactiae)
Group A streptococci under Lancefield clinical test
Streptococcus pyogenes
CLINICAL INFECTIONS OF S. PYOGENES
Gas (Group A streptococci) infection
“Strep throat” – most often seen in children between 5 and 15 years of age
Bacterial Pharyngitis
How do bacterial pharyngitis spread
Droplet and close contact
How many day of incubation period of bacterial pharyngitis
1-4 days
Sign and symptoms of bacterial pharyngitis
Sore throat
Malasie
Fever
Headache
Nausea
Vomiting
Abdominal pain
Tonsils and pharynx are inflamed
Swollen and tender cervical lymph nodes
a localized skin disease, begins as small vesicles that progress to weeping lesions; inoculation of organisms through minor abrasions or insect bites
Impetigo
followed by deeper invasion of streptococci; life-threatening; with bacteremia or sepsis.
- Patients with peripheral vascular disease or diabetes – leads to gangrene
Cellulitis
is a rare infection of the skin and subcutaneous tissues observed frequently in elderly patients
Lesion characteristics: acute spreading, intensely erythematous with plainly demarcated but irregular edge
Erysipelas
is a rare infection of the skin and subcutaneous tissues observed frequently in elderly patients
Lesion characteristics: acute spreading, intensely erythematous with plainly demarcated but irregular edge
Erysipelas
caused by streptococcal pyrogenic exotoxin
Scarlet fever
Diffuse red rash on upper chest and spreads to the trunk and extremities
Scarlet fever
Flesh-eating disease or syndrome”, “Suppurative fasciitis”, “Hospital gangrene”, “Necrotizing erysipelas” Life-threatening if early intervention is not done
Necrotizing Fasciitis (NF)
An uncommon invasive infection characterized by rapidly progressing inflammation and necrosis of the skin, subcutaneous fat, and fascia
Necrotizing fasciitis
A condition in which the entire organ system collapses, leading to death; reported since 1980s
Streptococcal toxic shock syndrome
Two serious complications or sequelae of GAS disease: postreptococcal sequelae
Rheumatic Fever
Acute Glomerulonephritis
Characterized: 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
What is the drug treatment for gas
Penicillin
If the patient that has GAS is allergic to penicillin what drug treatment should used
Erythromycin
Significant cause of invasive disease in newborn; Most infections of infants occur in the first 3 days after birth, usually within 24 hours (identified in 1970s)
Streptococcus agalactiae
Two clinical syndromes are associated with neonatal GBS disease: streptococcus agalactiae
early-onset infection and late-onset infection
pneumonia and sepsis; <7 days old; accounts for ~80% of newborn clinical cases; mostly due to vertical transmission from mother (in vagina or rectal area)
Early-onset infection
meningitis and sepsis; at least 7 days old to about 3 months old; Commonly associated with obstetric complications, prolonged rupture of membranes, and premature birth
Late-onset infection
Drug of choice for treatment for late onset infection
Penicillin
Some clinicians recommend a combination for GBS infection
Ampicillin and aminoglycoside
S. equi subsp. zooepidemicus (animal pathogen; glumerolonephritis and dramatic fever)
Group C and G streptococci
Classified with the pyogenic streptococci; Beta-hemolytic isolates – belong to the subspecies S. dysagalactiae subsp. equisimilis (also exhibited group A and L antigens); common in domestic animals
Large-colony forming isolate
Beta-hemolytic isolates – belong to the S. anginosus group (Under viridans streptococci group)
Small-colony forming isolate
isolated from variety of infections
Streptococcus pneumoniae/pneumococcus/diplococcus
Most frequently isolate in children younger than 3 years old with recurrent otitis media
Streptococcus pneumoniae
In gram stain morphology streptococcus pneumoniae
Gram-positive cocci in pairs (diplococci)
common procedure to identify S. pnemoniae from viridans streptococci
Optochin Susceptibility Test
Chemical composed of ethylhydrocupreine hydrochloride
Optochin test/ taxo P
What is susceptible in optochin test/taxo p
Pneumococci
What is resistant in optochin test/taxo p
Viridans streptococci
Determines the lysis of S. pneumoniae in the presence of bile salts
Bile solubility test
Test used only for streptococcus pneumoniae
Bile solubility test
is used only if organism is alpha-hemolytic.
Optochin test and bile test
Test used Only S. pneumoniae can ferment inulin (carbohydrate)
Inulin fermentation
What is the indication of inulin fermentation
Phenol red
What is the positive result and organism of inulin fermentation
Yellow (streptococcus pneumoniae)
What is negative result and organism of inulin fermentation
Red/pink (viridans group)
Biochemical reaction where antibodies bind to the capsule of S. pneumonia which allows visualization of bacteria under microscope
Capsular Swelling Reaction or Nueffeld Quellung Reaction
Biochemical reaction where antibodies bind to the capsule of S. pneumonia which allows visualization of bacteria under microscope
Capsular Swelling Reaction or Nueffeld Quellung Reaction
What is the positive result and organism of Capsular Swelling Reaction or Nueffeld Quellung Reaction
Obvious cell wall or capsule (streptococcus pneumoniae)
What is the negative result and organism of capsule swelling reaction
No capsule ( all other alpha hemolytic streptococci)
identified strains of S. pneumoniae which is virulent and non-virulent when injected into mice
Mouse virulence test
Who is involves in mouse virulence test
Fred neufeld
Positive result of mouse virulence test
Death of test animal
Test for previous infection of S. pneumoniae
Francis Skin Test
Erythrogenic test; Patient must not have rashes; 2-3 days
Francis skin test
Positive result of francis skin test
Wheale formation in skin
Drug of choice for s. Pneumoniae
Penicillin
Normal flora of the upper respiratory tract, female genital tract and gastrointestinal tract
Streptococcus pneumoniae
means “green”; referring to the alpha-hemolysis ability of many species
Viridans
Are opportunistic pathogens but can, cause disease in compromised defenses.
Viridans streptococci
The most common cause of viridans streptococci
Subacute bacterial endocarditis
normal flora of oral cavity and gastrointestinal tract; Associated with abscess formation in the oropharynx, brain and peritoneal cavity
Streptococcus anginosus group
normal flora of oral cavity, gastrointestinal tract and female genital tract; also transient normal flora of the skin; Most common isolates associated with bacterial endocarditis in native valves and less frequently, in prosthetic valve infections
Streptococcus mitis group
most commonly isolated among the viridans streptococci; Usually isolated from the oral cavity
Streptococcus mutan
primary contributor to dental caries; Most common member of the mutans group associated with bacteremia
Streptococcus mutan
Frequent cause of nosocomial infection – UTI (most common) followed by bacteremia; Prolonged hospitalization is a risk factor for acquiring enterococcal bacteremia
Enterococci
receiving hemodialysis, immunocompromised patients with a serious underlying disease, prior surgical procedure
Bacteremia
elderly patients with prosthetic valves or valvular heart disease. Accounts for ~10% of bacterial endocarditis.
Endocarditis
SPECIES: S. pyogenes
Hemolysis:
Group of antigen:
Common name:
Disease:
Beta
A
Group a streptococci
Scarlet fever and pharyngitis
SPECIES: S. Agalactiae
Hemolysis:
Group of antigen:
Common name:
Disease:
Beta
C
Group C streptococci
Pharyngitis and pyogenic infection
SPECIES: S. Faecalis
Hemolysis:
Group of antigen:
Common name:
Disease:
Beta
D
Group D streptococci
wound infection and bacteremia
SPECIES: S. Bovis and S. Equinus
Hemolysis:
Group of antigen:
Common name:
Disease:
Alpha/gamma
D
Non-Enterococci
Wound infection and endocarditis
SPECIES: S. Pneumoniae
Hemolysis:
Group of antigen:
Common name:
Disease:
Alpha
None
Pneumonococcus/diplococcus
Meningitis and bacteremia
SPECIES: viridans
Hemolysis:
Group of antigen:
Common name:
Disease:
Alpha/gamma
None
Viridans streptococci
Endocarditis
