Microbiology - Infective Endocarditis

Question 1

How does the blood culture bottle show if it is negative or positive?

Answer 1

By colour change:
Blue- negative
Orange- Positive
Slide 9

Question 2

What is infected endocarditis?

Answer 2

Infection of the endothelium of the heart valves. Slide 12

Question 3

What predisposes someone to getting infective endocarditis?

Answer 3

Heart valve abnormality e.g. rheumatic fever
Prosthetic heart valve
IV drug users
IV lines. Slide 14

Question 4

How does infective endocarditis occur?

Answer 4

Due to turbulence the endothelial lining is damaged, evoking an immune response and passing bacteria is able to stick onto the endothelial cells. Slide 16

Question 5

What are the 4 most common organisms that cause endocarditis?

Answer 5

Staph. Aureus
Viridans Strep.
Enterococcus
Staph. Epidermidis. Slide 18

Question 6

What are atypical causes of endocarditis?

Answer 6

Bartonella
Coxiella burnetii
Clamydia
Legionella
Mycoplasma
Brucella 
Slide 19

Question 7

What does HACEK stand for?

Answer 7

They are all gram negative organisms
Haemophilus
Aggregatibacter spp
Cardiobacterium, Eikenella sp.
Kingella sp.
Slide 19

Question 8

What is the Duke Major criteria for infective endocarditis?

Answer 8

Two separate positive blood cultures with microogansism for infective endocarditis
Echocardiographic evidence of endocardial involvement
New valvular regurgitation
Slide 20

Question 9

What is the next step after a transthoracic echocardiogram for investigating infective endocarditis if it is negative but you are still suspicious?

Answer 9

Transoesophageal Echocardiogram. Slide 21

Question 10

What organisms usually infects prosthetic material?

Answer 10

Staphylococcus Epidermidis. Slide 24

Question 11

When do you suspect if an organism found in a blood culture is a contaminent or not?

Answer 11

If there are only a few blood bottles with the organism in it e.g. 2/6 bottles. Slide 24

Question 12

How do people with acute endocarditis present and what organism does it tend to be?

Answer 12

Present with overwhelming sepsis and cardiac failure.

Usually Drug users and often infected with virulent organisms such as Staph. Aureus. Slide 29

Question 13

What are the symptoms and signs of subacute Infective endocarditis?

Answer 13

Symptoms: Fever, weight loss, tiredness, breathlessness.
Signs: New/changed heart murmur, finger clubbing, splinter haemorrhages, splenomegaly, microscopic haematuria. Slide 31

Question 14

What do roth spots, janeway lesions and osler nodes indicate?

Answer 14

Infective Endocarditis. Slide 31

Question 15

How can you tell if the organism causing the endocarditis is Viridans Strep.?

Answer 15

It is alpha (partial) haemolysis on agar.

However there are other organisms that are alpha too but Viridans is most common. Slide 32

Question 16

If the blood culture is negative, should you just rule out infective endocarditis?

Answer 16

No, some organisms e.g. atypical and fungi do not culture well.
Order serology and hold onto cultures logner to ensure you’re not missign anything. Slide 35

Question 17

If there is infective endocarditis due to a prosthetic heart valve, what is the medication?

Answer 17

Vancomycin
Gentamycin
Rifampacin (wait a few days before administering)
Slide 41

Question 18

Where is the mostly spot for drug users to get infective endocarditis and what are possible complications?

Answer 18

On the right side of the heart (passes through their first) and on the tricuspid valve.
However this means septic emboli can fly off the vegetations and shower the lungs. Slide 43

Question 19

What types of antibiotics do you use, what do you use for native valve and drug user endocarditis?

Answer 19

Has to be bacteriacidal antibiotics.
Native valve: Amoxicillin and gentamicin
Drug user: Flucloxacillin. Slide 44

Question 20

For specific organisms what antibiotics are administered; Staph. Aureus (MRSA treat as prosthetic), Viridans strep., Entero, Staph. Epidermidis?

Answer 20

Staph. Aureus: Flucloxacillin
Viridans strep: Benzylpenicillin + Gentamicin
Entero: Amoxicillin/vancomycin + gentamicin
Staph. Epidermidis: Vancomycin + gentamicin + rifampacin
Slide 47

Question 21

Who gets myocarditis and what are the symptoms and signs?

Answer 21

Young people
Symptoms: Fever, chest pain, SOB, palpitations
Signs: Arrhythmias, cardiac failure. Slide 53

Question 22

What are the causes of myocarditis and how is it treated?

Answer 22

Enteroviruses - Coxsackie A and B, echovirus etc very long list
Supportive treatment; antiinflammatories. Slide 54

Question 23

What is the main feature of pericarditis and what does it accompany?

Answer 23

Chest pain

It usually occurs with myocarditis. Slide 58

Question 24

What is the main organism which causes pericarditis and if it was bacterial what would the treatment be?

Answer 24

Usually viral with supportive treatement

Can be bacterial however and that treatment would consist of antibiotics and drainage. Slide 58