32 Questions
What is a characteristic of Streptococcus species that grow both at 45°C and 37°C but not at 10°C?
They may have A, C, G, or N antigen.
Which Streptococcus species is non-hemolytic with Lancefield N antigen and is found in dairy products?
S. lactis
How can Enterococci spp. be classified based on Smith & Brown's classification?
Based on the color of the RBC around colonies.
Which Streptococcus species is associated with green streptococci and is part of the normal fecal flora?
S. bovis complex
What distinguishes β-hemolytic Streptococcus species from other groups?
Growth preferences at specific temperatures.
Why might some Streptococcus species be able to withstand temperatures above 60°C?
As part of their normal habitat in human intestine.
Which virulence factor of Group A Streptococci is responsible for resisting phagocytosis and adherence to mucosal cells?
M Protein
Which adhesion molecule of Group A Streptococci mediates epithelial cell attachment?
Protein F
What is the function of the Hyaluronic Acid Capsule of Group A Streptococci?
Prevents opsonized phagocytosis by PMN or macrophages
Which Streptococcus serotype is most common in causing pharyngitis?
M1
How are Group A Streptococci mainly acquired?
Via contaminated droplets released through coughing and sneezing
What is the main function of the M Protein in Group A Streptococci?
Resists complement activation
What is the main function of streptokinase?
Causes lysis of fibrin clots
Which hemolysin is oxygen stable and nonimmunogenic?
Streptolysin S (SLS)
What inhibits Streptolysin O (SLO)?
Cholesterol in skin lipids
What is the main function of Deoxyribonuclease (DNase)?
Lowers viscosity of exudates
What type of hemolysis does Streptolysin S (SLS) cause?
Extracellular hemolysis
What is the function of Streptodornase?
Lowers viscosity of exudates
What is the function of Streptococcal Pyrogenic Exotoxins (SPEs)?
Acting as superantigens and activating macrophages
Which bacterial toxin degrades protein and mediates rashes seen in scarlet fever?
Exotoxin B
What is the role of C5a peptidase in bacterial infections?
Inactivating chemotactic factors for neutrophils
How do Streptococcal Pyrogenic Exotoxins (SPEs) contribute to shock and organ failure?
By acting as superantigens
What is the incubation period for bacterial pharyngitis or tonsillitis?
1 to 4 days
Which type of streptococci grow as 'satellite colonies' around other bacteria?
Granulicatella and Abiotrophia
What characteristic feature is shared by Streptococcus-like organisms Aerococcus, Gemella, Lactococcus, Leuconostoc, and Pediococcus?
Growth in 6.5% NaCl
Which Streptococcus-like organism is associated with infections similar to enterococci and streptococci?
Leuconostoc
Which Streptococcus-like organism does not produce acid from carbohydrates?
Lactococcus
Which Streptococcus-like organism resembles viridans streptococci on culture but microscopically is similar to staphylococci?
Aerococcus
Which Streptococcus-like organism is associated with infections such as sepsis, meningitis, bacteremia, and UTIs?
Globicatella sanguinis
'Abiotrophia' and 'Granulicatella' are formerly known as what?
"The Vitamin B6-dependent Streptococci"
Which Streptococcus-like organism is associated with wound infections?
Helcococcus kunzii
'Aerococcus urinae' is associated with which of the following infections?
UTI, endocarditis, lymphadenitis, and peritonitis
Test your knowledge of Streptococcus bacteria characteristics and classifications, including growth temperatures, hemolysis types, Lancefield groups, and antigen variations. Identify different species like S. salivarius, S. mutans, S. mitis, S. sanguis, and S. anginosus.
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