Aerobic Gram Positive Cocci Flashcards
What is catalase?
An enzyme that breaks down hydrogen peroxide into water and oxygen.
Is Staphylococcus catalase positive or negative?
Catalase positive.
Is Streptococcus catalase positive or negative?
Catalase negative.
What is the function of coagulase?
Coagulase converts fibrinogen to fibrin, leading to clot formation.
Which organism is primarily identified by the coagulase test?
Staphylococcus aureus.
What does DNase do?
DNase is an enzyme that degrades DNA.
True or False: Bacitracin is an antibiotic that inhibits cell wall synthesis.
True.
What is the purpose of the bacitracin sensitivity test?
To differentiate Streptococcus pyogenes from other beta-hemolytic streptococci.
What does the CAMP test detect?
The presence of the CAMP factor produced by Streptococcus agalactiae.
True or False: Optochin is used to differentiate Streptococcus pneumoniae from other alpha-hemolytic streptococci.
True.
What is the Lancefield classification used for?
To categorize beta-hemolytic streptococci based on carbohydrate composition of antigens.
What Lancefield group is Streptococcus pyogenes classified into?
Group A.
What Lancefield group is Streptococcus agalactiae classified into?
Group B.
Fill in the blank: Staphylococcus species are typically _____ hemolytic.
beta or non-hemolytic.
What is the primary pathogenic species of Staphylococcus?
Staphylococcus aureus.
What type of hemolysis does Streptococcus pneumoniae exhibit?
Alpha hemolysis.
True or False: All Staphylococcus species are coagulase positive.
False.
What is the clinical significance of DNase production?
It helps in identifying pathogenic strains of Staphylococcus aureus.
What test can be used to identify Streptococcus pneumoniae?
Optochin sensitivity test.
Fill in the blank: The presence of _____ is a key factor in identifying Streptococcus agalactiae.
CAMP factor.
What is the main virulence factor of Staphylococcus aureus?
Protein A.
Which organism is known for causing necrotizing fasciitis?
Streptococcus pyogenes.
What is the appearance of a positive coagulase test?
Clot formation in the test tube.
True or False: Bacitracin is effective against Streptococcus pneumoniae.
False.
What test differentiates Staphylococcus saprophyticus from Staphylococcus epidermidis?
Novobiocin sensitivity test.
What does a positive CAMP test indicate?
The organism is likely Streptococcus agalactiae.
What is the primary role of the Lancefield classification system?
To identify groups of streptococci based on their carbohydrate antigens.
Fill in the blank: Optochin sensitivity is used to differentiate Streptococcus pneumoniae from _____.
Streptococcus viridans.
True or False: All beta-hemolytic streptococci are Lancefield group A.
False.
Which Staphylococcus species is often associated with urinary tract infections?
Staphylococcus saprophyticus.
What type of agar is used to perform the bacitracin sensitivity test?
Blood agar.
Fill in the blank: The coagulase test is typically performed on _____ species.
Staphylococcus.
What is the significance of DNase production in Staphylococcus aureus?
It indicates the organism’s ability to degrade DNA and is a marker for virulence.
What type of hemolysis is exhibited by Streptococcus pyogenes?
Beta hemolysis.
What is the primary method of identifying Streptococcus pneumoniae?
Optochin sensitivity test.
Fill in the blank: Lancefield groups are designated by letters from _____ to _____.
A to V.
What is the main differentiating factor between Staphylococcus epidermidis and Staphylococcus aureus?
Coagulase production.
What does a negative DNase test indicate?
The organism does not produce DNase.
True or False: Streptococcus pneumoniae is optochin resistant.
False.
What type of infections is Streptococcus agalactiae commonly associated with?
Neonatal infections.
What is the genus of Enterococcus?
Enterococcus
Are Enterococcus species gram-positive or gram-negative?
Gram-positive
Which type of hemolysis is typically associated with Enterococcus?
Gamma hemolysis
True or False: Enterococcus can be part of the normal intestinal flora.
True
What color does Enterococcus produce on bile esculin agar?
Black
What is bacitracin used for in microbiology?
To differentiate between streptococci species.
Fill in the blank: Enterococcus faecalis is a common species found in _______.
Human intestines
What type of infections are commonly associated with Enterococcus species?
Urinary tract infections
Which Enterococcus species is most frequently isolated from clinical specimens?
Enterococcus faecalis
True or False: Enterococcus is resistant to many antibiotics.
True
What is the primary distinguishing factor between alpha, beta, and gamma hemolysis?
The ability to lyse red blood cells and change the color of the agar.
Which hemolytic pattern shows complete lysis of red blood cells?
Beta hemolysis
What is the significance of bile esculin hydrolysis?
It indicates the ability of an organism to grow in the presence of bile and to hydrolyze esculin.
Which hemolytic pattern is characterized by no lysis of red blood cells?
Gamma hemolysis
What test can be used to differentiate Enterococcus from Streptococcus?
Bile esculin test
Fill in the blank: Enterococcus species are known for their _______ resistance.
Vancomycin
What is a common characteristic of Enterococcus in laboratory culture?
They can grow in high salt concentrations.
True or False: Enterococcus can be pathogenic in immunocompromised individuals.
True
What type of bacteria are Enterococcus often confused with due to similar morphology?
Streptococcus
Which Enterococcus species is often associated with endocarditis?
Enterococcus faecalis
What is the role of bacitracin in differentiating Streptococcus species?
It inhibits the growth of certain bacteria, helping to identify species.
Fill in the blank: Enterococcus is a facultative _______.
Anaerobe
What is the main clinical concern regarding Enterococcus species?
Antibiotic resistance
Which of the following is a characteristic of beta-hemolytic bacteria? A) Partial lysis B) No lysis C) Complete lysis
C) Complete lysis
True or False: All Enterococcus species are pathogenic.
False
