Infection with bacteria and other germs in the blood can be deadly. How long germs stay in the blood is important for two reasons. The first is that if they stay in the blood for many days it is a sign that antibiotics may need to be changed. The second is that if they stay in the blood for only a short time it may give doctors confidence to switch to tablets and consider early discharge from hospital. This study is evaluating the diagnostic and prognostic performance of two novel technologies when used to measure the duration of the bloodstream infection.
Bloodstream infection is highly significant and is associated with mortality rates of between 10 and 25%. For some infection types (for example, Staphylococcus aureus) a longer duration of bacteria being present in the blood is linked to higher mortality. With traditional microbiologic techniques, bloodstream infection with gram-negative bacteria is usually quite brief. However, new culture independent bacteraemia detection systems (such as T2 magnetic resonance assay) are more sensitive than traditional blood culture systems and may show that gram-negative bacteraemia is more prolonged in some patients than has previously been thought. This observational study will investigate the correlation between the duration of bloodstream infection by mean of traditional blood culture techniques with: 1. Duration of the bloodstream infection by mean of the T2 magnetic resonance assay, a new culture independent bacteraemia detection system. 2. Persistence of inflammation as measured by the SeptiCyte RAPID test, a host response assay able to differentiate infectious from sterile inflammation. The study will also correlate each measure of the duration of bacteraemia with microbiological and clinical outcomes.
Study Type
OBSERVATIONAL
Enrollment
102
Caboolture Hospital
Brisbane, Queensland, Australia
Redcliffe Hospital
Brisbane, Queensland, Australia
Royal Brisbane and Women's Hospital
Brisbane, Queensland, Australia
Duration of bloodstream infection measured by conventional blood cultures and the T2 magnetic resonance assay
The T2 system is a new diagnostic detection method utilizing miniaturized magnetic resonance technology. The T2 system has been shown to quickly and accurately identify molecular targets within patient samples without the need for purification or extraction of target molecules from the sample. It does not require bacterial culture and can detect organisms as low as 1 CFU/mL in whole blood. The study will compare the duration of detectable pathogens in the bloodstream as measured by the T2 with the duration of bloodstream infection according to conventional cultures
Time frame: Days 1-4
Persistent infection defined as metastatic infection and lack of source control
The study will explore the correlation between the duration of detectable pathogens in the bloodstream as measured by the T2 (duration of T2emia) and the presence of persistent infection
Time frame: Days 1-4
Short-term clinical outcome (SOFA success)
The study will explore the correlation between the duration of detectable pathogens in the bloodstream as measured by the T2 (duration of T2emia) and short-term clinical outcome. A "successful short-term outcome" or "SOFA success" is defined as survival for the first 7 days from BSI onset with a stable or decreased Sequential Organ Failure Assessment (SOFA) score (for ICU patients) or modified SOFA score (for non-ICU patients), defined as follows: if the baseline SOFA/mSOFA \>=3, a decrease of at least 30% in that score, if the baseline SOFA/mSOFA \<3, a stable or decreased SOFA/mSOFA score. Patients discharged before day 7 will be assumed to have improved SOFA scores. The lack of "SOFA success" will be defined "SOFA failure".
Time frame: Days 1-7
Long-term clinical outcome
The study will explore the correlation between the duration of detectable pathogens in the bloodstream as measured by the T2 (duration of T2emia) and long-term clinical outcomes. A "successful long-term outcome" is defined as survival for the first 6 months from the BSI onset and maintenance of the baseline functional performance status defined by the functional bloodstream infection score (FBIS) score 7 days prior to the BSI onset.
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Time frame: 6-months from the index BSI
Persistent infection
SeptiCyte is a host-response assay able to differentiate infectious from sterile inflammation by providing a score (SeptiScore) from 1-15. It is approved for the diagnosis of sepsis in ICU patients. Whether SeptiScore may have a role in diagnosing the persistence of the infection in patients with proven BSI is unknown. The study will explore the performance of SeptiScore in diagnosing persistent infection including persistent BSI and metastatic infection
Time frame: Day 1-4