Background Infectious endocarditis (IE) is associated with high morbidity and mortality, so it is necessary to detect and treat the disease at an early stage with the most appropriate antimicrobial regimen to reduce its mortality and its serious complications.

Purpose To analyse the adequacy of antibiotic treatment in IE by Staphylococcus aureus (SA) and to assess morbidity and mortality associated.

Material and methods Retrospective observational study carried out from August 2014 to March 2017.

Variables were: demographic data, empirical or target antimicrobial treatment (E/T), methicillin-resistant or methicillin-susceptible SA (MRSA/MSSA) and native or prosthetic valve endocarditis (NVE/PVE). The degree of adequacy of the antimicrobial regimen in IE by SA was analysed according to the consensus document published by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC)) in 2015, which recommends the following therapy:

1. Empirical treatment for clinical suspicion of IE by MSSA or MRSA: E-MSSA: cloxacillin ±daptomycin. E-MRSA: cloxacillin +daptomycin.

2. Target treatment with diagnosis of IE either by MSSA or MRSA either in PVE or NVE: T-MSSA-NV: cloxacillin. In case of allergic to beta-lactams (T-MSSA-NVE-A): daptomycin +fosfomycin. T-MSSA-PVE: cloxacillin +rifampicin + gentamicin. T-MRSA-NVE: cloxacillin +daptomycin. T-MRSA-PVE: daptomycin +rifampicin + gentamicin.

To determine morbidity and mortality in these patients, the variables were: hospital stay, cardiac surgery performed, embolic complications and mortality.

Results Fifteen patients were treated for suspicion of IE by SA with an average age of 76 years, 73% of whom were males.

The adequacy of the antimicrobial treatment was the following: E-MSSA 100% (2/2 patients), E-MRSA 25% (1/4), T-MRSA-NVE 0% (0/4, because in all, daptomycin was associated with cloxacillin), T-MSSA-NVE-A 100% (1/1), T-MSSA-PVE 0% (0/2, because daptomycin was in all), 100% (1/1) and T-MRSA-PVE 0% (0/1, because neither rifampicin nor gentamicin was associated). The degree of adequacy to the consensus document was 33%.

Average hospital stay was 47 days. Of the nine patients with definite IE by SA: 33% (3/9) cardiac surgery was required, 56% (5/9) had embolic complications and 44% (4/9) died during their hospital admission.

Conclusion Because of the low degree of adequacy registered and the fact that optimal treatment is still being discussed, it would be convenient to establish a protocol in our hospital for the treatment of IE by SA and reduce its morbimortality.

No conflict of interest