28F presents with two months of intermittent fevers and a new murmur.  You suspect infective endocarditis.

 

With this subacute presentation, how many blood cultures should you order? How far apart?  What empiric antibiotics are indicated?

 

What if the patient is unstable? how many blood cultures should you order? How far apart?  What empiric antibiotics are indicated?

How much blood should be in each culture bottle?

Subacute

Three blood cultures

12-24 hours apart

NO Empiric therapy–treatment should be based on culture results and susceptibilities

Unstable

Three blood cultures

over one hour

Vancomycin (30 mg/kg per 24 h IV divided q12)

 

Each culture should have 5-10ml of blood added, you can check this by looking at the hash marks on the side of the label and watching the volume go up.