Invasive Markers of Staphylococcus Epidermidis

Study Overview
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Brief Summary
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The purpose of the study is to identify biomarkers allowing the distinction between invasive and non-invasive strains of Staphylococcus epidermidis. This distinction is important to determine if the patient is infected and, as a consequence, if an antibiotic treatment is required.

Detailed Description
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In the hospital, a large proportion of bacteraemia and implantable medical device infections are caused by Staphylococcus epidermidis. This microorganism is the most abundant on human skin and all patients are carriers. Its remarkable ability to form biofilms on most materials explains that catheter-related infections are by far the most common. S. epidermidis infections are difficult to treat because most strains are multi-resistant and antibiotics are less effective in the presence of biofilms. In addition, S. epidermidis poses a major diagnostic problem because it is also the first source of contamination of blood culture sample and intraoperative samples (in case of suspected infection of orthopedic material in particular). Thus, when a sample is positive for S. epidermidis, there is less than a 25% chance that it reflects true bacteremia in the patient and 30% of patients would inappropriately receive vancomycin following contaminated blood cultures. Differentiating a contamination of a blood or intraoperative sample from true S. epidermidis infection is therefore crucial for patient management because unnecessary antibiotic therapy is potentially responsible for the emergence of resistant strains, toxicity and additional costs. The objective of this study is to identify the genetic markers that make it possible to differentiate the strains causing infections from the strains causing contamination by comparing their genomes using high throughput sequencing.

Official Title
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Identification of Genomic Markers Associated With the Invasiveness of Staphylococcus Epidermidis Strains Responsible for Infections

Conditions
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Staphylococcus Epidermidis Positive Blood Culture

Intervention / Treatment
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* Diagnostic Test: high-throughput sequencing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: CASE Inclusion Criteria: Population 1: nosocomial bacteraemia associated with intravascular devices Hospitalized patient with intravascular device (peripheral or central, venous or arterial, short or long duration) for at least 48 hours before the development of bacteraemia Presenting a definite infection with S. epidermidis according to the categorization criteria, Sub-Population 1A: 3a) Aged less than 28 days (New-born) Sub-population 1B: 3b) Aged 28 days or more Population 2: nosocomial infections of implanted material An operated patient carrying implanted equipment following orthopaedic surgery, following cardiac surgery or following neurosurgery, Presenting a definite infection with S. epidermidis according to the categorization criteria occurring in the year following surgery CONTROL Inclusion Criteria: Population 1: carrier of intravascular devices Hospitalized patient with intravascular device (peripheral or central, venous or arterial, short or long duration) for at least 48 hours before positive blood culture with S. epidermidis Certain contamination with S. epidermidis according to the categorization criteria, Sub-Population 1A: 3a) Aged less than 28 days (Newborn) Sub-population 1B: 3b) Aged 28 days or more Population 2: carrier of implanted material An operated patient carrying implanted equipment following orthopedic surgery, following cardiac surgery or following neurosurgery, Presenting a certain contamination to S. epidermidis according to the categorization criteria occurring in the year following surgery Exclusion Criteria: CASE Exclusion Criteria Population 1: nosocomial bacteremia associated with intravascular devices Opposition of the patient or the holders of parental authority (minor patients) Patient with polymicrobial infection Patient with a colonized catheter (positive catheter end culture <103UFC / mL) with no clinical signs of local or general infection and with sterile peripheral blood cultures Patient with local catheter infection (positive catheter end culture> 103UFC / mL) with local inflammatory signs only and with sterile peripheral blood cultures Population 2: nosocomial infections of implanted material Opposition of the patient or the holders of parental authority (minor patients) Patient with an infection of material concomitant with a catheter-related infection CONTROL Exclusion Criteria Populations 1 and 2: Opposition of the patient or the holders of parental authority (minor patients)
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 |
| --- | --- |
| S. epidermidis Infection (CASE)<br>Patients with confirmed infection at S. epidermidis | Diagnostic Test: high-throughput sequencing<br>* technique of high-throughput sequencing of the markers present in the genome of the S. epidermidis strains responsible for infection in order to help to discriminate the true infections of the contaminations<br>|
| S. epidermidis Contamination (CONTROL)<br>Patients with confirmed contamination at S. epidermidis | Diagnostic Test: high-throughput sequencing<br>* technique of high-throughput sequencing of the markers present in the genome of the S. epidermidis strains responsible for infection in order to help to discriminate the true infections of the contaminations<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| genetic markers of S. epidermidis | to identify genetic markers associated with a significant risk of invasive S. epidermidis infections | at the time of the positive sampling of S. epidermidis | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation of the genotype with the characteristics of the infections | identification of genetic markers specifically associated with a type of infection (catheter-related bacteremia in newborns, catheter-related bacteremia in patients 28 days or older, infections of orthopedic equipment or infections of cardiac equipment) | at the time of the positive sampling of S. epidermidis | 
| Intra-hospital cross-transmission detection | The comparison of the strains will be based on the study of the variations in the part of the genome that is common to all the strains to detect possible transfers between patients | at the time of the positive sampling of S. Epidermidis | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Staphylococcus epidermidis Infection, Staphylococcus epidermidis Contamination, intravascular device, implanted material