Pathogens Causing Endocarditis Flashcards
What investigation can show vegetation in infective endocarditis?
Echocardiogram
How many sets of blood cultures should you take and what should be different about each set?
3 sets from different sites
What bacteria is causing the IE if investigations show gram positive cocci in chains that is alpha haemolytic and optochin resistant?
Viridians streptococci
How do you treat IE caused by Viridians streptococci?
Benzylpenicillin given intravenously for 4-6 weeks. Give gentamicin for the first two weeks if it is less sensitive
How can you tell a blood culture bottle has become positive?
Turbidity increases, lysis of RBCs, increases in carbon dioxide
What happens when blood culture bottles become positive?
They are removed from incubation and sub-cultures are made onto solid media
What bacteria is causing the IE if investigations show gram positive cocci in clusters that are yellow on blood agar and give a positive coagulase test?
S.aureus
What drug should you start if the causative organism is S.aureus?
IV flucoxacillin
The patient has become short of breath, they are hyperventilating and their oxygen sats are 92%. What has happened?
They’ve developed cavitating staphylococcal pneumonia from septic emboli
How does cavitating staphylococcal pneumonia look on a CXR?
Ring shapes
What IE is classic in IV drug users?
Right sided endocarditis caused when S.aureus from the skin is introduced into the blood
What drug should you change to if S.aureus is determined to be MRSA?
Vancomycin
Are prosthetic valves a risk factor for IE?
Yes
What bacteria is likely to be causing IE if they are gram positive cocci in clusters that are white on blood agar and coagulase negative?
S.epidermidis
Why should you take multiple blood cultures from different sites?
In case one set gets contaminated with bacteria on the skin and not causing a problem
