difficulties in including patients with Staphylococcus aureus infection

There are more than one million (> 40,000 cases per year in France) of osteoarticular infections (OAI) yearly in the world. The number of these infections is constantly increasing due to an increase in life expectancy associated with an increase in prosthesis fitting, as well as an increase in comorbid factors. These are severe pathologies associated with mortality (5%) and significant morbidity (40%), responsible for functional sequelae with an individual cost (prolonged hospitalization, altered quality of life, disability) and societal (sick leave, partial disability). or total, temporary or permanent) extremely high. In addition, reinfection rates within two years of treatment are high.

The BJIs are a group of clinical entities that have in common the invasion and progressive destruction of bone and cartilage tissue by bacterial-like microorganisms.

Staphylococcus spp is the main pathogen (>50%) in BJI and is associated with particularly difficult to treat infections, with a high rate of chronicity and relapses, especially in case of implanted material.

The difficulty in managing these infections is partly linked, on the one hand, to the fact that the pathogens are in "persistent" metabolic forms and in intracellular reservoirs which make them insensitive to conventional antibiotics and, on the other hand, the absence of reliable markers of the infection and above all of its clinical resolution, which complicates clinical trials.

ESPRI-IOAC is a consortium of 4 partners (private-public) from Lyon area and which aims at:

• studying the translational value of BJI preclinical models
• identifying biomarkers of infection in preclinical models and at assessing them in a prospective study.

The current study is part of the global ESPRI-IOAC consortium, and represent the clinical application.

It is a prospective study of patients treated for BJI in the infectious disease department of the Hospices Civils de Lyon, La Croix-Rousse, for osteo-articular infections due to Staphylococcus aureus, or for simple mechanical revision or for cruciate ligament surgery, the objective of which is to highlight biomarkers of interest in the diagnosis of chronic BJI and, or predictive of the therapeutic response.

The translational value of the experimental models used in the BJI will also be studied.

Inclusion Criteria:

• Age ≥ 30 years old
• Hospitalized in orthopedic surgery for one of these reasons:
• A suspected infection or a documented proven infection with staphylococcus aureus on prosthesis or other orthopedic implant
• A mechanical cause (absence of infection) on prosthesis or orthopedic implant
• Documented chronic osteomyelitis due to staphylococcus aureus
• Cruciate ligament surgery
• Patient not subject to any legal protection measure
• Patient who can be followed in the Infectious and Tropical Diseases Department, CRIOAC Lyon ("Centre de Référence des Infections Ostéo-Articulaires complexes" = reference centre of bone and joint infections in french), La Croix-Rousse for at least 6 months post-surgery
• Patient who gave his no-opposition
• Patient giving his consent to the creation of biological collections

Exclusion Criteria:

• Polymicrobial infection
• Known inflammatory disease
• Hyperthyroidism
• Cushing's disease
• Osteomalacia
• Renal osteodystrophy
• Paget's disease
• Malignant disease in progress
• Multiple myeloma
• Bone metastases
• Ehlers-Danlos syndrome
• Pregnant or lactating woman
• Renal impairment (Creatinine clearance <60 mL / min)
• Trauma in the 6 months preceding surgery
• Fracture in the 6 months preceding surgery
• Corticosteroid therapy in progress at the time of inclusion
• Active infection with HIV (human immunodeficiency virus), HBV (hepatitis B virus), HCV hepatitis C virus) documented in the patient file
• Antibiotic treatment in the 15 days preceding inclusion
• People placed under judicial protection

Patients treated in the orthopedic surgery and infectious diseases departments of the Hospices Civils de Lyon, Croix-Rousse Hospital, for osteo-articular infections, due to Staphylococcus aureus, for simple mechanical revision or for cruciate ligament surgery.