Molecular detection of the bacterial load as a diagnostic and monitoring tool for optimal antibiotic treatment in endocarditis

Endocarditis is a serious life-threatening condition. Rapid diagnosis and
monitoring of response to treatment is very important, because of the
significant risk of infection-related complications and/or therapeutic failure.
Diagnosis often takes several days due to blood culturing which causes a delay
in instalment of appropriate treatment. Commonly used laboratory parameters for
monitoring such as CRP and leucocytes are not specific enough to detect a
complicated treatment course. Molecular detection of the bacterial load (mBL)
has been shown to be pathogen-specific, and is directly correlated to severity
of disease in bloodstream-related infections. It has the potential to be used
as a rapid tool (<5hrs) for diagnostics and therapeutic monitoring of patients
with endocarditis. This could lead to earlier diagnosis and detection of a
complicated treatment course, which enables pre-emptive strategies to improve
outcome.

Primary objectives:
- Evaluation of the value of mBL as a diagnostic tool for bacterial
endocarditis.
- Evaluation of the value of mBL as a monitoring tool during treatment for
bacterial endocarditis.
- To obtain data on the kinetics of mBL related to infectious parameters in
patients with bacterial endocarditis.

Secondary Objectives
- Value of mBL to determine the severity of bacterial endocarditis at start of
therapy.
- Value of mBL to predict treatment-course at start of therapy for bacterial
endocarditis.
- Evaluation of markers of the host response in patients with bacterial
endocarditis.

This study is a multicenter prospective observational study. All adult patients
who are suspected for bacterial endocarditis, and are hospitalized or
presenting at the emergency department in the participating hospitals, are
eligible for the study. Routine diagnostic work-up to will be performed in
these patient to confirm or reject the diagnosis bacterial endocarditis. These
patients will be asked for informed consent to participate in this study.
Enrolled patients suspected for bacterial endocarditis will be followed up by
performing serial blood measurements and by recording clinical information from
the patients medical record and the automated patient data management system.
In the first week of follow up daily blood sampling is performed. Follow up
sampling will be continued in patients in whom the treating physician continues
treatment for endocarditis. Follow up is continued during endocarditis therapy.
If endocarditis is rejected, sampling is discontinued instantly.

Patient burden for this study is limited since routine blood tests are
performed regularly in patients with endocarditis. Therefore sampling for this
study mostly entails adding an extra EDTA-bottle to the routine procedure. To
keep patient burden low we have set a maximum per patient of six extra
venepunctures for purpose of the study.
The amount of blood obtained from included patients for purpose of this study
will usually be between 96-192ml. The maximum amount of blood obtained for
study purposes is set at 250 ml.