Local antibiotic treatment guidelines should be consulted when prescribing, however, some general guidance is given here for the following situations:
Infective endocarditis can be caused by a wide range of organisms, although viridans streptococci and
Staphylococcus aureus between them are responsible for most cases. Identification of the causative organism by taking multiple blood culture is crucial to guiding therapy. The two basic principles of therapy are that:
- Bactericidal (e.g. penicillins) rather than bacteriostatic (e.g. macrolides) antibiotics should be used
- Long term therapy - weeks rather than days - is required
There are detailed published guidelines which are updated regularly and these should be consulted when a case is encountered. Advice from Microbiology or Infectious Disease specialists is often obtained. The latest UK guidelines were published in 2012:
Gould et al. J Antimicrob Chemother 2012;67:269-289
In outline, typical antibiotic regimes might be as follows in the next two tabs.
I.V. Benzylpenicillin plus gentamicin for 2 weeks, followed by benzylpenicillin alone for a further 2 weeks. Although streptococci are intrinsically resistant to gentamicin, there is synergy between the two agents and the combination is beneficial. Vancomycin would be the alternative in patients who are penicillin allergic.
I.V. Flucloxacillin for 4 - 6 weeks if sensitive. Vancomycin for MRSA or in patients who are penicillin allergic.
Prosthetic valve endocarditis is a special case and advice should be sought.
