Incidence of Cutibacterium acnes from shoulder arthroplasties in Asians: ethnic differences should be considered

A systematic review of distinction of colonization and infection in studies that address Cutibacterium acnes and shoulder surgery

BACKGROUND

After shoulder surgery, infection is often diagnosed in the absence of an inflammatory host response (purulence, sepsis). In the absence of inflammation, the more appropriate diagnoses may be colonization or contamination. We reviewed the available data regarding culture of Cutibacterium acnes during primary and revision shoulder surgery and asked; 1) what is the prevalence of air, skin, and deep tissue colonization? 2) How often is an inflammatory host response associated with diagnosis of postoperative shoulder infection diagnosed on the basis of culture of C. acnes? 3) Is there any relation between culture of C. acnes and outcomes of shoulder surgery?

METHODS

Three databases were searched for studies that address C. acnes and colonization or infection related to shoulder surgery. We analyzed data from 80 studies addressing the rates of C. acnes colonization/infection in patients undergoing shoulder surgery, evidence of an inflammatory host response, and relationship of C. acnes culture to surgery outcomes.

RESULTS

C. acnes is often cultured in the air in the operating room (mean 10%), the skin before preparation (mean 47%), and deep tissue in primary shoulder arthroplasty (mean 29%), arthroscopy (mean 27%), and other shoulder surgery (mean 21%). C. acnes was cultured from a mean of 39% of deep tissue samples during revision arthroplasty. C. acnes was believed to be the causative organism of a high percentage of the infections diagnosed after surgery, 39% in primary shoulder arthroplasties, 53% in revisions, 55% in arthroscopic surgeries, and 44% in a mixture of shoulder surgeries. Infection was nearly always diagnosed in the absence of an inflammatory host response. Documented purulence and sepsis were not specifically ascribed to C. acnes (rather than more virulent organisms such as S. aureus). Diagnosis of infection, or unexpected positive culture, with C. acnes during shoulder surgery is associated with outcomes comparable to shoulders with no bacterial growth.

CONCLUSIONS

The evidence to date supports conceptualization of C. acnes as a common commensal (colonization), and perhaps a frequent contaminant, and an uncommon cause of an inflammatory host response (infection). This is supported by the observations that 1) unexpected positive culture for C. acnes is not associated with adverse outcomes after shoulder surgery, and 2) diagnosed infection with C. acnes is associated with outcomes comparable to noninfected revision shoulder arthroplasty. We speculate that diagnosis of C. acnes infection might represent an attempt to account for unexplained discomfort, incapability or stiffness after technically sound shoulder surgery. If so, the hypothesis that stiffness and pain are host responses to C. acnes needs better experimental support.

A Literature Review of Cutibacterium Acnes: From Skin Commensal to Pathogen in Shoulder Surgery

Cutibacterium acnes, previously known as Propionibacterium acnes, is a gram-positive rod in the pilosebaceous glands and commonly implicated in acne vulgaris. Its role in prosthetic joint infections, particularly in shoulder surgeries, has recently gained attention due to its prevalence around the shoulder girdle. This review collates evidence on the pathogenic role of C. acnes in shoulder surgeries, discussing preventive measures, risk factors, clinical presentation, investigation, and treatment strategies. C. acnes infections are complex, often presenting with non-specific symptoms and delayed diagnoses. Risk factors include male sex, presence of hair, shoulder steroid injections, and previous shoulder surgeries. Investigations such as inflammatory markers, synovial fluid analysis, diagnostic arthroscopy, tissue cultures, and advanced molecular techniques like next-generation sequencing and multiplex polymerase chain reaction are explored for their effectiveness in detecting C. acnes. Treatment strategies range from prolonged antibiotics and antibiotic spacers to single-stage and two-stage revision surgeries. Studies indicate that single-stage revision may provide better outcomes compared to two-stage revision. Effective management of C. acnes infections requires careful assessment, relevant investigations, and tailored treatment approaches. This review emphasizes the need for further research to address intraoperative contamination and to develop more efficient diagnostic and treatment methods.

Extended skin cleaning on the shoulder with chlorhexidine reduces the cutaneous bacterial load but fails to decrease suture contamination in patients undergoing arthroscopy rotator cuff repair

BACKGROUND

It remains unclear whether preoperative skin cleaning of the chin, neck, and chest with chlorhexidine soap can reduce suture contamination by Cutibacterium acnes in patients undergoing arthroscopic rotator cuff repair.

METHODS

This study included patients who underwent primary arthroscopic rotator cuff repair. Exclusion criteria included age <18 years, previous shoulder surgery, history of shoulder infection, and allergy to chlorhexidine. Patients were randomized into 3 groups. Patients in the control group cleaned their skin with soap and water, as usual. Patients in the shoulder group cleaned their shoulders with chlorhexidine soap 3 days before surgery, whereas patients in the extended shoulder group additionally cleaned their chest, back, neck, and face with chlorhexidine soap. On the day of surgery, skin swab samples were obtained from the shoulder after surgical draping. After rotator cuff repair, sutures were cut from the anchor ends. Both traditional culture methods and polymerase chain reaction (PCR) were used.

RESULTS

Ninety patients were enrolled (32 in the control group, 29 in the shoulder group, and 29 in the extended shoulder group) in the present study. The culture-positive rate from the posterior shoulder skin samples in the extended shoulder group (17.2%) was significantly lower than that in the control (40.6%) and shoulder (48.3%) groups (P = .036), whereas the culture-positive rates were not different among the 3 groups in other skin samples as well as the suture samples. The detection rates of C acnes in suture samples were 12.5%, 13.8%, and 17.2% in the control, shoulder, and extended shoulder groups, respectively (P = .603).

CONCLUSION

Extensive skin cleaning of the shoulder region with chlorhexidine helps reduce the shoulder cutaneous bacterial load, but the detection of C acnes suture contamination in patients undergoing arthroscopic rotator cuff repair remained untouched regardless of the use of chlorhexidine soap in skin cleaning on the preoperative days.