Endocarditis

Consult a microbiologist where possible. Alpha-haemolytic streptococci are the most common causes of native valve endocarditis, but Staphylococcus aureus is more likely if the disease is rapidly progressive with high fever, or is related to a prosthetic valve (Staphylococcus epidermidis). Three sets of blood cultures should be taken before starting treatment.

Native Valve Endocarditis

Empirical treatment:

	Medicine	Adult dose	Frequency	Duration
	benzylpenicillin iv	5MU	6 hourly	2-6 weeks
or	ceftriaxone 1g iv	1g	12 hourly	2-6 weeks
and	gentamicin iv	80-120mg	12 hourly	2 weeks

*Total duration of antibiotic therapy should be 4 - 6 weeks if there is evidence of improvement.

*Treatment can be changed to oral therapy after at least 2 weeks of IV antibiotics if there is marked improvement.

Prosthetic Valve Endocarditis

Initially:

	Medicine	Adult dose	Frequency	Duration
	cloxacillin iv	2g	6 hourly	4-6 weeks
and	gentamicin iv	80-120mg	12 hourly	4 weeks

It is important to measure serum gentamicin levels every 3-4 days. One hour peak concentration should not exceed 10mg/L and trough concentration (2hour pre-dose) should be less than 2mg/l.

Treatment of Culture Positive Endocarditis

Streptococcal infection (e.g. Strep. viridans):

	Medicine	Adult Dose	Frequency	Duration
	benzylpenicillin iv	5MU	6 hourly	4-6 weeks
and	gentamicin iv	80-120mg	12hourly	4 weeks

Enterococcal infection (e.g. Enterococcus faecalis):

	Medicine	Adult dose	Frequency	Duration
	benzylpenicillin iv	5MU	6 hourly	4-6 weeks
and	gentamicin iv	80-120mg max-120mg	12 hourly	4 weeks

Staphylococcal infection (for example, Staph. aureus & Staph. epidermidis):

	Medicine	Adult Dose	Duration	Frequency
	cloxacillin iv	2g	6 hourly	4-6 weeks
and	gentamicin iv	80-120mg	12 hourly	4 weeks

At any stage, treatment may have to be modified according to:

detailed antibiotic sensitivity tests
adverse reactions
allergy
failure of response

Endocarditis leading to significant cardiac failure or the failure to respond to antibiotics may well require cardiac surgery.

Prophylaxis against endocarditis - no special risk

Dental procedures, upper respiratory tract, obstetrics and gynaecological procedures under local or no anaesthesia (no special risk):

Medicine

Adult Dose

Frequency

Duration

amoxicillin po

Paed = 50mg/kg

one dose only

one hour before procedure

clindamycin po

in penicillin allergy or recent penicillin administration (< one month)

600mg

<5yrs = 150mg

5-10yrs = 300mg

one dose only

one hour before procedure

Dental procedures, upper respiratory tract, obstetrics and gynaecological procedures under general anaesthesia (no special risk):

	Medicine	Adult Dose	Frequency	Duration
	ampicillin iv	1g at induction, then 500mg after 6 hours
or	amoxicillin po	3g 4hrs before anaesthesia, then 1g 6 hours post op

If penicillin allergy or recent administration of penicillin within the previous month see under special risk groups below.

Prophylaxis against endocarditis - special risk:

Prosthetic valve in situ, or previous endocarditis or genitourinary procedures (special risk groups)

	Medicine	Adult Dose	Frequency	Duration
	ampicillin iv	1g	at induction	single dose
and	gentamicin iv	120mg	at induction	single dose

If penicillin allergy or administration of penicillin in the past month:

	Medicine	Adult Dose	Frequency	Duration
	clindamycin iv*	300mg	at induction	single dose
and	gentamicin iv	120mg	at induction	single dose

*Do not use clindamycin for urological/gynaecological procedures because it will not prevent enterococcal infection. In these cases replace clindamycin with vancomycin iv 1g over at least 100 minutes 1- 2 hours before procedure.