The efficacy of topical preparations in reducing the incidence of Cutibacterium acnes at the start and conclusion of total shoulder arthroplasty: a randomized controlled trial

These authors investigated whether preoperative application of topical antimicrobials to the skin reduced superficial colonization and deep tissue inoculation of Cutibacterium in patients undergoing total shoulder arthroplasty who were randomized to receive either topical

pHisoHex (hexachlorophene (n = 35),

5% BPO (n = 33), or

5% BPO with 1% clindamycin (n = 33).

The initial demographics are shown here. Of note the percentage of male patients was lower for the BPO-C group than for the other groups.

Skin swabs for culture were obtained

prior to topical application and

before surgery after topical application

3 intraoperative swabs were obtained at surgery

dermis after incision,

on joint capsule entry, and

dermis at wound closure

The results are shown below - the three agents performed in a similar fashion. Of note, one of the groups (BPO) differed from the other two in respect to the percentage with colonization before any treatment was applied.

These data show that Cutibacterium can persist in the dermis despite 5 applications of topical skin preparation: 22% of cases had positive dermal cultures at the beginning of the case.

A positive Cutibacterium skin culture finding prior to surgery was predictive of intraoperative wound contamination: all 24 cases that had a positive swab culture before starting the procedure had at least one positive culture intraoperatively; in most cases, all subsequent swabs showed positive results.

Thus, failure to eradicate Cutibacterium from the skin with topical preparations consistently was associated with deep tissue inoculation.

None of the 101 control sterile swabs were culture positive for Cutibacterium.

Comment: This study demonstrated that surface washes can reduce the percent of positive skin surface cultures. There were no untreated controls, so the effect of the washes on dermal cultures at incision, joint cultures, and dermal cultures at closure is not known. While it is recognized that young male patients are at greatest risk for Cutibacterium periprosthetic infections, the study group consisted of older patients, one third of which were female.

The authors found that all control sterile swabs were culture negative for Cutibacterium and concluded that "There is, therefore, no need for control swabs to be included in future C acnes studies". Actually, this is not the case. As pointed out in An Evidence-Based Approach to Managing Unexpected Positive Cultures in Shoulder Arthroplasty the pooled rate of positive control cultures (sterile gauze, sterile swabs, and sterile suture) reported in the literature was 20%. Cutibacterium represented 14 (48%) of the 29 total control positives. Thus, it seems important that each investigator assess the rate of sterile control culture positivity for Cutibacterium in their environment.

In conclusion, evidence is lacking that skin preparations can reduce the rate of positive deep wound cultures for Cutibacterium in patients known to be at high risk for Cutibacterium periprosthetic infections. In high risk patients (i.e. young male patients with high loads of Cutibacterium on their skin prior to surgery) surgeons may wish to consider the intraoperative use of Betadine washes, topical Vancomycin, and a course of postoperative oral antibiotics.

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