Endocarditis Pathogens Flashcards
Why should blood cultures be taken away from site of infection
Avoid contamination
What are the main signs of Infective Endocarditis
Osler nodes Janeway Lesions Roth spots Splinter haemorrhage Septic emboli
How is a blood culture generally taken
10ml blood incubated (aerobic and anaerobic for 7 days)
Bacteria grows and lyse RBC = increase CO2
Bacteria detected as positive
Positive cultures are then grown and gram stained
What do optochin disks differentiate
S Pneumo vs Alpha haemolytic Strep
What organism is Optochin sensitive
S Pneumo
What organism is Optochin resistant
S Viridans
What does it mean to be optochin resistant
No zone of inhibition so bacteria grows around disk
What does S Viridans commonly cause
IE and is associated with poor dental hygiene affecting native valves
How is S Viridans treated
IV Benzylpenicillin +/Gentamycin
What is the most common cause of IE
S Aureus (+ve catalase and coagulase w/gold colonies) -Typical with IVDU
What valve does S Viridans typically affect
Native valves
What valves does S Aureus affect
Prosthetic and Tricuspid (IVDU)
Where can a septic emboli arise from
CV Vegetation
What Staph bacteria can cause IE
S Aureus (+ve catalase +ve coagulase, gold colonies) S Epidermidis (+ve catalase -ve coagulase, white colonies)
What is a fungal source of IE
Candida albicans
- Budding and (+ve) purple w/gram stain
- Cream cony on Sabourard
