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Which of the following is NOT a common form of infection caused by Enterococci?
Which of the following is NOT a common form of infection caused by Enterococci?
Which of the following tests is NOT typically used to identify Enterococci in the laboratory?
Which of the following tests is NOT typically used to identify Enterococci in the laboratory?
What are the two most common species of Enterococcus associated with disease in humans?
What are the two most common species of Enterococcus associated with disease in humans?
Enterococcus faecalis and Enterococcus faecium
What is the most common form of infection associated with Enterococci?
What is the most common form of infection associated with Enterococci?
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Which two tests are used to differentiate Enterococcus from Streptococcus?
Which two tests are used to differentiate Enterococcus from Streptococcus?
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What type of hemolysis is associated with Streptococcus pyogenes?
What type of hemolysis is associated with Streptococcus pyogenes?
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Which of the following is a virulence factor of Staphylococcus aureus?
Which of the following is a virulence factor of Staphylococcus aureus?
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Streptococcus epidermidis causes acute endocarditis, which may rapidly develop.
Streptococcus epidermidis causes acute endocarditis, which may rapidly develop.
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Streptococcus pyogenes is a catalase-positive bacterium that is commonly present in the normal microbiota of the nose and throat, and is associated with several invasive infections such as strep throat, scarlet fever and invasive wound infections.
Streptococcus pyogenes is a catalase-positive bacterium that is commonly present in the normal microbiota of the nose and throat, and is associated with several invasive infections such as strep throat, scarlet fever and invasive wound infections.
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Staphylococcus epidermidis is the leading cause of prosthetic valve endocarditis.
Staphylococcus epidermidis is the leading cause of prosthetic valve endocarditis.
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What is the name of the antigen that is often associated with glomerulonephritis?
What is the name of the antigen that is often associated with glomerulonephritis?
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What is the name of the enzyme produced by bacteria that degrades hyaluronic acid, which is found in connective tissue?
What is the name of the enzyme produced by bacteria that degrades hyaluronic acid, which is found in connective tissue?
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What is the name of the enzyme that converts fibrinogen to fibrin, leading to the formation of blood clots?
What is the name of the enzyme that converts fibrinogen to fibrin, leading to the formation of blood clots?
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What is the name of the substance that enhances the attachment of bacteria to host cell surfaces?
What is the name of the substance that enhances the attachment of bacteria to host cell surfaces?
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Coagulase is an enzyme that is produced by Staphylococcus aureus and other staphylococci species?
Coagulase is an enzyme that is produced by Staphylococcus aureus and other staphylococci species?
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Staphylococcus epidermidis is a catalase-positive bacterium?
Staphylococcus epidermidis is a catalase-positive bacterium?
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What are the most common portals of bacterial entry into the bloodstream?
What are the most common portals of bacterial entry into the bloodstream?
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Bacteremia can be a result of an organism multiplying at a local infection site and being drained to the bloodstream via the lymphatic system?
Bacteremia can be a result of an organism multiplying at a local infection site and being drained to the bloodstream via the lymphatic system?
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Septicemia is another name for bacterial infection.
Septicemia is another name for bacterial infection.
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Septic shock is a complication of sepsis that can lead to hypotension and organ failure.
Septic shock is a complication of sepsis that can lead to hypotension and organ failure.
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Study Notes
Bacterial Infections of the CVS and Lymphatics
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Definitions:
- Bacteremia: Presence of bacteria in the blood, often entering through lymphatic systems from a local infection site.
- Septicemia/Sepsis: Presence of bacteria and toxins in the blood, causing harm to the host. Common signs include fever, chills, hypotension, and organ failure.
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Staphylococci:
- S. aureus: Gram-positive cocci in clusters, coagulase-positive. Common causes of skin infections (e.g., folliculitis, furuncles), food poisoning, and endocarditis. Important virulence factors include exotoxins (e.g., TSST-1, exfoliative toxins).
- S. epidermidis: Gram-positive cocci in clusters, coagulase-negative. Often part of normal skin flora, it can cause infections, especially in prosthetic devices. Key virulence factor: biofilm formation.
- Laboratory Diagnosis: Gram stain, catalase test, coagulase test, novobiocin susceptibility test, hemolysis.
- Treatment: Removal of infected devices, methicillin-sensitive S. aureus (MSSA) treatment with nafcillin, oxacillin, or cefazolin, Vancomycin recommended for methicillin-resistant S. aureus (MRSA), alternatives include daptomycin and linezolid.
- Prevention: Cleanliness, aseptic techniques, careful management of wounds.
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Streptococci:
- Group A Streptococcus (S. pyogenes): Gram-positive chains. Common causes include pharyngitis (strep throat), skin infections (impetigo). Key virulence factor: M protein (involved in rheumatic fever and glomerulonephritis).
- Viridans Streptococci: Common part of normal oral flora. Often causes subacute endocarditis (e.g., S. mutans is a major player in dental caries).
- Group D Streptococci: Includes S. bovis. Often associated with bacteremia.
- Enterococci: Gram-positive, catalase-negative. Often part of GI tract. Can cause UTI. Differentiated from non-enterococci with PYR test, bile solubility, and salt tolerance tests.
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Laboratory Diagnosis:
- Gram stain
- Catalase test
- Coagulase test
- Novobiocin susceptibility test
- Bile esculin test
- Optochin susceptibility test
- Salt tolerance test
- Hemolysis test
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Endocarditis: Infection of heart valves, often caused by bacteria entering the bloodstream. Risk factors: previous heart conditions, implantations, and IV drug use.
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Treatment and Prevention: Specific treatment for each pathogen is mentioned in the relevant section. General prevention measures include aseptic techniques, good oral hygiene, and management of infections at their source.
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