Incidence of Culture Positive Propionibacterium acnes in Shoulder Arthroscopy

Objectives:Accurate detection and diagnosis of Propionibacterium acnes infection after shoulder surgery is often challenging. Aspiration and tissue cultures yield both false negative and false positive cultures and determination of infection is not always straightforward. The purpose of our study was to measure P. acnes positive cultures from patients undergoing arthroscopic surgery, with no previous surgical history on that shoulder. Our hypothesis was that P. acnes would not be found in patients who had not previously had shoulder surgery.Methods:Seven samples were collected from 57 consecutive patients undergoing shoulder arthroscopy, without any previous shoulder surgery. An air swab was taken as a control for this study. Two skin swabs (one after skin preparation and one prior to skin closure), aspiration of joint fluid, and three samples of debrided tissue were obtained for culture. All samples were placed on three different aerobic plates and held for 48 hours. Samples were also plated on anaerobic...