Microbiology Flashcards
What are the most often infected valves for infectious endocarditis?
Mitral and aortic
Inflammation of the inner heart lining due to an infectious agent is called…
Infectious endocarditis
Septic emboli often result in what clinical manifestation?
petechiae and splinter hemorrhages
What may you see in the eye of someone with infectious endocarditis?
Roth spots
What are the major Duke criteria for infectious endocarditis?
Positive blood culture
Evidence of endocardial involvement
What are the 5 minor Duke criteria?
- Predisposition (heart condition or IV abuser)
- Fever above 100.3
- Vascular phenomena (petechiae, etc.)
- Immunologic phenomena (Roth’s spots, Osler’s nodes, rheumatoid factor)
- Microbiologic evidence not meeting major criteria
What proteins are used by Staph aureus to evade host defenses? What do they do?
Protein A: Binds Fc of Ig
Coagulase: Forms fibrin coat around organism
Hemolysins: Destroy RBC
Leukocidins: Destroy WBC
What virulence factors are associated with Staph Aureus invading deep into tissue? What do they do?
Hyaluronidase: Destroys connective tissue
Staphylokinase: Lyses clots
Lipase: Breaks down fat tissue
What is the most common endocardial infectious agent with a patient with mitral valve tissue damage?
Streptococcal viridans
What are the 3 most common infectious agents for endocarditis?
- Staph aureus
- Strep viridans
- Enterococcus
What virulence factors do you worry about with an enterococcus infection?
Pili
Surface proteins
Hyaluronidases
Proteases
What two antibiotic groups are enterococci resistant to?
Penicillin, Carbapenems
Streptococcus pyogenes has six virulence factors. What are they and what do they do?
Streptokinase: converts plasminogen to plasmin
M protein: Prevents host phagocytosis
Hyaluronidase: destroys connective tissue
DNase: Digests DNA
Streptolysin S: Destroys WBC’s
Streptolysin O: Destroys RBC’s
In Rheumatic fever, what is the bacterial protein that is responsible for antibody formation? What do antibodies attack?
M protein
Meromyosin
How do you treat rheumatic fever?
Corticosteroids
Penicillin based antibiotics
Aspirin
Rest
What are the main causes of myocarditis?
Coxsackie virus B and adenovirus (children)
What receptor do coxsackie and adenovirus attack on the heart?
CAR (Coxsackie and Adenvirus) receptor
What infectious agents are responsible for pericarditis?
Coxsackie A and B, Echoviruses, Influenza
What causes RMSF?
Rickettsia rickettsii
What do you use to treat RMSF?
Doxy
