Different mechanisms have been proposed to explain the pathophysiology of chronic staphylococcal BJI, including biofilm formation and the ability of staphylococci to be internalized and to survive within cells. The intracellular localization of staphylococci is well documented by in vitro studies, however, few studies have shown the presence of intracellular staphylococci in clinical specimens from patients with BJI.

The aim of the CRISBO study is to document the clinical relevance of intracellular staphylococci in the context of BJI. Immunostaining targeting staphylococci and components will be carried out on tissue samples taken from patients with BJI during their treatment (samples similar to those used for routine diagnosis in pathology). Our objectives are to identify whether intracellular staphylococci are observable in these samples and if so, in which cell type (s) are they housed.

Inclusion Criteria:

• patients having had an osteo-articular infection with Staphylococci

Exclusion Criteria:

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patients having had an osteo-articular infection with Staphylococci managed at the Croix-Rousse Hospital