Isolation of Coxiella burnetii from an acromioclavicular infection with low serological titers.

•Coxiella burnetii was isolated from an acromioclavicular synovial biopsy.•C. burnetii acromioclavicular infection is a new clinical entity.•Evidence of persistent C. burnetii infectious foci with low serological titres was found.•This report highlights the crucial role of PET imaging in identifying the deep infectious focus.