Infective Endocarditis Flashcards
steps to development of infection
- valve surface altered
- deposition of platelets and fibrin
- bacteria bind to NBTE, colonize
- build-up occurs, more fibrin, more bacteria
3 organisms that commonly cause acute endocarditis
- S. aureus
- S. pneumoniae
- S. pyogenes
2 organisms that commonly cause subacute endocarditis
- S. viridans
- HACEK
organisms that cause prosthetic valve endocarditis
- early (60 days) - Streptococci
most common organism causing endocarditis in IVDU
- S. aureus
virulence factors favoring colonization
- dextran production: retards antimicrobial therapy
- FimA: surface adhesion protein, mediates attachment to platelet-fibrin molecules
lab characteristics of S. aureus
- coagulase +
- catalase +
- beta hemolytic
- mannitol salt +
characteristics of Abiotrophia spp.
- requires L-cysteine or pyridoxal vitamin B6
- NF of URT, urogenital tract, and GI
- seen in subacute endocarditis
- prone to systemic embolization
characteristics of group D strep
- grows in 6.5% NaCl
- bile esculin positive
- PYR positive
characteristics of S. mutans
- associated with cavities
- bile -esculin positive
characteristics of S. bovis
- NF of GI tract
- does not grow in 6.5% NaCl
- associated with GI lesions and colon cancer
HACEK organisms
- Haemophilus parainfluenzae
- Aggregatibacter
- Cardiobacterium hominus
- Eikenella corrodens
- Kingella kingae
presentation of HACEK
- granular growth in broth
- large friable vegetations
- frequent emboli
- development of CHF
difference between Haemophilus parainfluenzae and influenzae
- parainfluenzae grows on blood and chocolate agar
- influenzae only grows on chocolate
characteristics of aggregatibacter
- most common HACEK infection
- associated with periodontal disease
- significant embolization
characteristics of cardiobacterium hominus
- associated with periodontal disease
- typically absence of fever
- large vegetations, large vessel emboli
characteristics of eikenella
- smells like bleach
- pitting on agar
- common in IVDU, especially with amphetamines
characteristics of kingella
- arthritis seen in children
Duke criteria for definite IE
- 2 major
- 1 major, 3 minor
- 5 minor
Duke criteria for possible IE
- 1 major and 1 minor
- 3 minor
Major criteria
- positive blood culture
- evidence of endocardial involvement
Minor Duke criteria
- predisposing conditions
- fever > 100.4
- vascular phenoma: mycotic aneurysm, conjunctival hemorrhages, Janeway lesions
- Immunologic phenomena: Oslers nodes, Roth spots
- Microbiological evidence
- echo findings
additional lab findings associated with IE
- elevated rheumatoid factor titers
