Cutibacterium acnes in primary reverse shoulder arthroplasty: from skin to deep layers

The aim of this study was to determine the presence of Cutibacterium acnes (formerly Propionibacterium acnes) on the skin and in deep tissue in a real clinical scenario of primary reverse shoulder arthroplasty.

This prospective study included 90 primary reverse shoulder arthroplasties, and 12 cultures were obtained from each patient. Each sample was homogenized and used to inoculate PolyVitex (bioMérieux, Marcy-l'Etoile, France) agar and Schaedler (bioMérieux) agar plates. The same procedure was also followed with a thioglycolate broth. Culture was considered positive for C acnes when 2 or more colonies were observed. Total DNA from C acnes isolates was extracted using the InstaGene Matrix (Bio-Rad Laboratories, Hercules, CA, USA) method. The phylotype was determined, and single-locus sequence typing was done on all isolates.

We obtained 1080 tissue cultures from the 90 patients included, and 62 of those tissue cultures (5.7%) were positive for C acnes. There were 22 C acnes-positive tissue cultures before prosthesis implantation and 40 after implantation. C acnes was isolated in 17 patients (18.8%). We sent 38 positive samples for blinded phylotyping, single-locus sequence typing, and multi-locus sequence typing type determination. Many of the clusters isolated belonged to phylotype IB and clonal complex (CC) 36 or phylotype II and CC53.

In the real scenario of patients undergoing primary reverse shoulder arthroplasty using antibiotic prophylaxis and standard preoperative skin preparation with chlorhexidine, C acnes was isolated in the deep layers of 18.8% of the patients. The C acnes K1 and K2 subtypes (belonging to phylotype II and CC53), reported to be commonly involved in prosthetic joint infection, were usually isolated.