Duration of therapy for native valve endocarditis caused by methicillin-susceptible staphylococci

For patients with uncomplicated native valve endocarditis caused by methicillin-susceptible staphylococci, 4 weeks of antibiotic therapy is often adequate. For patients with complicated infections (eg perivalvular abscess, septic metastatic complications), use 6 weeks of therapy. However, close monitoring of these sequelae is required and may increase treatment duration.

Patients with right-sided (tricuspid valve) methicillin-susceptible staphylococcal endocarditis (usually people who inject drugs) can be treated with a short course (2 weeks) of flucloxacillin if all the following criteria are metBaddour, 2015Habib, 2015:

• no associated prosthetic valve or left-sided valve infection
• no metastatic infection, such as osteomyelitis, lung abscess or empyema
• no cardiac or extracardiac complications
• no right-sided heart failure or acute respiratory failure
• vegetation smaller than 10 mm
• clinical and microbiological response within 72 to 96 hours of starting therapy
• no severe immune compromise.

However, it is unusual for all these criteria to be met in the majority of such high-risk patientsShmueli, 2020.