Therapy

• immediately if endocarditis is strongly suspected ^a, otherwise
• once there is a positive blood culture ^c

Why?

• Patients suspected of having bacterial endocarditis partially treated with antibiotics are less likely to have positive blood cultures. ^c

Antibiotics reduce the chance of a positive blood culture.

Patient	Treatment	Comparison	Outcome	CER	RRR (95% CI)	NNH (95% CI)
suspected infective endocarditis c	antibiotics before a positive blood culture	no antibiotics	any positive blood culture at 3 weeks	97%	-6% (-10% to -1%)	18 (10 to 70)

 

Note:

• The commonest infective organisms are Staphylococcus and Streptococci (20%). ^b

 

Streptococcus and Staphylococcus are common causes

organism b	prevalence
Viridans streptococci	42%
Staphylococcus aureus	18% to 23%
All streptococci	20%
Enterococci	8%
Other streptococci	8%
HACEK group	6%
'Culture negative'	2%

 

*HACEK = Haemophilus, Actinobacillus, Cardiobacterium, Eikinella and Kingella spp