Corynebacterium Spp Bone and Joint Infection: Retrospective Study of Microbiological, Diagnostic and Therapeutic Features

Study Overview
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Brief Summary
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Corynebacterium spp have been considered as innocuous commensals of human skin, but are now accepted as important opportunistic pathogens responsible for various nosocomial infections, especially implicating foreign materials. In particular, they accounted for up to 10% of prosthetic joint infection (PJI), and are mostly identified in chronic forms of bone and joint infections (BJI). However, little is known about the pathophysiological pathway implicated in Corynebacterium BJI, species distribution and antimicrobial susceptibility, and the management of these difficult-to-treat clinical entities. This study aims to report a retrospective cohort of patients with Corynebacterium spp BJI, aiming to : i) describe microbiological characteristics of the implicated clinical isolates, including species identification and antimicrobial susceptibility (and especially according to previous antimicrobial exposure); ii) assess pathophysiological mechanisms associated with BJI chronicity, including biofilm formation and bone cell invasion, to better understand mechanisms of Corynebacterium spp and to evaluate their ability to distinguished colonizing and infective isolates; iii) describe the medical (nature and duration of antimicrobial therapy) and surgical management of these patients; and iv) evaluate the patient outcome according to this management strategy, and highlight risk factor for treatment failure in order to improve patient's management.

Official Title
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Corynebacterium Spp Bone and Joint Infection: Retrospective Study of Microbiological, Diagnostic and Therapeutic Features

Conditions
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Corynebacterium Infections

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients (i.e age ≥ 18-year-old) with microbiologically proven Corynebacterium bone and joint infection, with or without implant Exclusion Criteria: diabetic foot osteomyelitis pressure ulcer-associated osteomyelitis

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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Description of microbiological features of Corynebacterium infection | microbiological identification at species level will be confirmed for each isolate using routine mass spectrometry (MALDI-TOFF-MS) | at diagnosis | 
| antimicrobial susceptibility | antimicrobial susceptibility testing performed according to current guidelines of the French committee for antimicrobial susceptibility testing. Antimicrobial susceptibility profile will be interpreted according to previous exposition to antimicrobials, including new molecules such as daptomycin | at diagnosis | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ability of clinical isolate to form biofilm | The ability of clinical isolate to form biofilm will be assessed using the classic photometric method based on crystal violet staining, and the BiofilmRingTest dynamic method evaluating the kinetic of biofilm formation based on magnetic beads immobilization when embedded in biofilm | at diagnosis | 
| Corynebacterium isolate ability to invade and persist within bone cells | Corynebacterium isolate ability to invade and persist within bone cells will be adressed using an in vitro model of human osteoblastic cells infection, developed in our laboratory, as previously described | at diagnosis | 
| Surgical management and antimicrobial therapy in patients with bone or joint infection | Surgical management and antimicrobial therapy will be described and compared to current guidelines | at the end of follow up | 
| Treatment failure in patients with bone or joint infection | Treatment failure will include i) clinical and/or microbiological relapse after treatment disruption; ii) the need of additional surgery for septic reason; and iii) death related to the BJI or its management. | one to two years after the end of antimicrobial therapy | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Osteoblast, Antimicrobial susceptibility, Biofilm formation, Bone and joint infection, Corynebacterium spp, Outcome, Prosthetic joint infection