Study: P Acnes is Resistant to Skin Antisepsis Preparations

Propionibacterium acnes (P acnes) persists in the skin following shoulder surgery despite the use of a variety of skin antisepsis preparations and techniques, according to study data presented Thursday. Researchers in the department of orthopaedic surgery at the Keck School of Medicine of the University of Southern California, conducted the study to determine the efficacy of various skin preparations at eradicating P acnes in the dermal layer of the skin.

P acnes is an indolent organism responsible for the vast majority of infections following shoulder surgery and is the most common organism responsible for delayed implant infections,” coauthor Lakshmanan Sivasundaram, BS, said. “Despite standard surgical antisepsis techniques, P acnes continues to be implicated in the vast majority of deep surgical site infections in shoulder arthroplasty and shoulder arthroscopy patients.”

Study methods
Study participants included 12 healthy male volunteers older than age 18. Each participant’s upper back was prepped using five different techniques: isopropyl alcohol control, chlorhexidine gluconate, chlorhexidine gluconate plus mechanical scrub, high-concentration chlorhexidine gluconate plus mechanical scrub, and chlorhexidine gluconate plus vapocoolant spray. A 3-mm dermal punch biopsy specimen was obtained at each of the five preparation sites. The biopsy specimens were cultured for 14 days to assess for P acnes growth. Repeated measures logistic regression was used to compare the proportion of positive cultures in each group.

The researchers reported no complications in any of the subjects. P acnes grew in 7 of the 12 control sites, 5 of the 12 chlorhexidine gluconate sites, 6 of the 12 chlorhexidine plus mechanical scrub sites, 6 of the 12 high-concentration chlorhexidine gluconate plus mechanical scrub sites, and 6 of the 12 chlorhexidine gluconate plus vapocoolant spray sites. There were no statistically significant differences between any of the treatment arms (P = 0.526).

P acnes persisted in the skin despite a variety of skin antisepsis preparations and techniques utilized. According to the authors, these findings underscore the limitations of skin antisepsis to prevent P acnes infections following shoulder surgery.

“The variety of surgical preparations and techniques utilized in this study failed to alter the rate of P acnes growth in the dermal layer of the skin, suggesting that current superficial surgical antisepsis methods inadequately eradicate P acnes,” Mr. Sivasundaram said. “These results highlight the inadequacy of current surgical site preparations at eradicating one of the most common organisms responsible for implant-related infections. Future studies should investigate preparatory methods that penetrate epidermal layer of the skin, such as a topical antibiotic.”                          

Mr. Sivasundaram’s coauthors of Paper 538 “Propionibacterium Acnes Persists Despite Various Skin Preparation Techniques” are Nathanael Heckmann, MD; William C. Pannell, MD; Diego Villacis, MD; C. Thomas Vangsness Jr, MD; Reza Omid, MD; and George F. Hatch III, MD.

Details of the authors’ disclosures as submitted to the Orthopaedic Disclosure Program can be found in the Final Program; the most current disclosure information may be accessed electronically at