Diagnostic Performance of Plasma Procalcitonin for the Detection of Blood Cultures Contaminations

Study Overview
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Brief Summary
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In blood cultures, species considered as potentially contaminating (coagulase negative staphylococci (CNS), Bacillus spp., Corynebacterium spp., Cutibacterium acnes, Micrococcus spp., viridans group streptococci, and Clostridium perfringens) can, however, be responsable for true bacteremia. Blood levels of the prohormone procalcitonin (PCT) markedly increase in the early stages of bacterial infections. The aim of our study is to determine the role of plasma PCT as a biomarker differentiating blood culture contaminations from true bacteremia.

Detailed Description
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Blood culture contamination is defined by the introduction into of a microorganism into blood culture bottles from either the patient's or healthcare worker's flora, or the immediate environment during specimen collection. Species considered as potentially contaminating (coagulase negative staphylococci (CNS), Bacillus spp., Corynebacterium spp., Cutibacterium acnes, Micrococcus spp., viridans group streptococci, and Clostridium perfringens) can, however, be responsible for true bacteremia. If an organism belonging to one of those species is detected in isolates, rapidly and accurately assessing its contaminant or infectious potential is hence important to ensure effective antibiotic therapy as well as to reduce financial burden caused by unnecessary treatments, and additional clinical and laboratory costs. Blood levels of the prohormone procalcitonin (PCT) markedly increase in the early stages of bacterial infections. The aim of our study is to determine the role of plasma PCT as a biomarker differentiating blood culture contaminations from true bacteremia.

Official Title
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Diagnostic Performance of Plasma Procalcitonin in Screening for Contamination When Detecting Potential Contaminants in Blood Cultures

Conditions
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Blood Culture Contamination, Bacteremia, Contamination

Intervention / Treatment
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* Diagnostic Test: Procalcitonin dosage


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: At least one blood culture positive for of the following microorganisms: coagulase negative staphylococci, viridans group streptococci PCT levels measurement on the day of blood culture specimen collection Adult patients Exclusion Criteria: Patients with less than 3 blood culture bottles collected

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Positives blood cultures<br>Collection of clinical and biological data of patients with blood cultures positives for potential contaminants, as well as PCT levels measurements, from January 2016 to May 2019 at the Nancy CHRU | Diagnostic Test: Procalcitonin dosage<br>* Plasma PCT levels measured by automated enzyme immunoassay (Kryptor).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To evaluate the diagnostic potential of plasma procalcitonin in detecting blood culture contamination | True contamination will be considered if all of the following biological criteria are met: Only one bottle collected is positive The growth time in the first positive bottle is more than 20 hours Plasma proclacitonin levels measured by automated enzyme immunoassay (Kryptor). | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To compare plasma PCT levels in patients with true bacteremia, probable bacteremia and contamination caused by the presence of bacterial species with high contaminant potential | Bacteremia will be considered as present ( true bacteremia ) if all of the following biological criteria are met: The same microorganism (amongst CNS, viridans group streptococci) is isolated in 100% of blood culture bottles collected from a given patient The growth time in the first positive bottle is less than or equal to 16 hours Probable bacteremia: When biological criteria of bacteremia and contamination are not fulled When a antibiotic therapy is administrated without focal infection identified by cliniciens | 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Procalcitonin