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Hydrogen peroxide reduces C. acnes cultures following shoulder surgery



Prior to shoulder surgery, application of 3% hydrogen peroxide is a simple and inexpensive strategy to reduce the risk of postoperative cultures of Cutibacterium acnes, according to findings from a prospective randomized trial. The results were reported in an abstract scheduled for release at the annual meeting of the American Academy of Orthopaedic Surgeons. The meeting was canceled because of COVID-19.

“This approach is simple, cheap, and does not rely on patient compliance,” explained Surena Namdari, MD, associate professor of orthopedic surgery at Thomas Jefferson University, Philadelphia.

C. acnes, formerly known as Propionibacterium acnes, is increasingly seen as an important target for prevention of postoperative shoulder infections because of published reports that it is the most commonly isolated bacterium from such infections, Dr. Namdari said in an interview.

In the prospective, randomized trial, male patients scheduled for shoulder arthroscopy were recruited if they did not have active acne, history of psoriatic or eczematous lesions, or recent antibiotic use. Most of the preoperative preparation of the surgical site was the same in the experimental and control arms. This included hair clipping, application of 2% chlorhexidine, and cleansing with saturated 7.5% povidone-iodine solution surgical scrub brushes.

The difference was that 3% hydrogen peroxide–soaked gauzes were applied to perioperative skin of those randomized to the experimental group but not to controls. All patients received routine preoperative oral antibiotics as well as perioperative applications of a formulation containing 2% chlorhexidine gluconate and 70% isopropyl alcohol.

Following surgery, 11 (18.6%) of the 59 patients in the experimental arm versus 23 (34.8%) of the 66 patients randomized to the control group had positive cultures for C. acnes (P = .047), according to the trial results, which have now been published (J Shoulder Elbow Surg. 2020;29:212-6).

There were no cases of skin reactions in either the experimental or control groups.

Topical skin cleansers that contain peroxide, such as benzoyl peroxide, have been shown to have a C. acnes decolonizing effect if applied repeatedly in the days prior to surgery, but Dr. Namdari suggested the problem with this approach is that it depends on patient compliance. A prophylaxis included in the preoperative routine eliminates this potential problem.

C. acnes is an anaerobic bacterium that is part of the resident flora of the skin around several joints, including the knee and the hip, but it is particularly common in the posterior shoulder. Colonization has been found substantially more common in men than in women, according to Dr. Namdari.

The specific threat posed by C. acnes to risk of postoperative infections “is still being defined,” and this trial was not large enough to associate the reduction in postoperative C. acnes cultures with a reduced risk of an adverse clinical outcome, but Dr. Namdari says that the data do show that the nearly 50% reduction in positive cultures was achieved efficiently and inexpensively with no apparent risk.

Several previous studies have also evaluated strategies for reducing C. acnes skin burden on the basis of expected protection against postoperative infection. In one, which associated a 3-day preoperative course of benzoyl peroxide with a reduction in the skin burden of C. acnes, the authors also concluded that this approach deserves consideration in routine skin preparation for shoulder arthroplasty (J Shoulder Elbow Surg. 2018;27:1539-44).

“We believe that a preoperative skin prep protocol that reduces C. acnes load on the skin would likely lead to reduced postoperative infections,” reported the senior author, Mohit N. Gilotra, MD, assistant professor, University of Maryland, Baltimore. Contacted about the rationale for reducing C. acnes skin burden without objective evidence of an impact on postoperative infection risk, Dr. Gilotra indicated these strategies make sense.

“It seems to be true for staph infections and is a reasonable assumption to make here,” he added. “Future work will help determine how much benzoyl peroxide, hydrogen peroxide, or other skin prep can reduce surgical site infection.”

Dr. Namdari reports financial relationships with multiple device and pharmaceutical companies but none relevant to this study.

SOURCE: Namdari S et al. AAOS 2020. Abstract P0808.

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