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Published on: December 3, 2017
Contamination of the Surgical Field with Propionibacterium acnes in Primary Shoulder Arthroplasty
Travis M Falconer1, Mohammed Baba2, Lisa M Kruse3
1Perth Orthopaedic & Sports Medicine Center, West Perth, Australia ssri@sydneyshoulder.com.au.
Background:
Propionibacterium acnes is a common pathogen identified in postoperative shoulder infection. It has been shown to be present in culture specimens during primary shoulder arthroplasty; however, recent work has suggested that it is most likely to be a contaminant. Our aim was to identify the potential sources of contamination in shoulder arthroplasty.
Methods:
Tissue swabs were obtained for microbiological analysis from consecutive patients undergoing primary shoulder arthroplasty. Routine surgical technique was maintained, and 5 specimens were taken from different sites: (1) the subdermal layer, (2) the tip of the surgeon's glove, (3) the inside scalpel blade (used for deeper incision), (4) the forceps, and (5) the outside scalpel blade (used for the skin incision).
Results:
Forty patients (25 female patients and 15 male patients) were included. Thirteen (33%) of the 40 patients had at least 1 culture specimen positive for P. acnes. Two (8%) of the 25 female patients and 11 (73%) of the 15 male patients had ≥1 culture specimen positive for P. acnes. The most common site of growth of P. acnes was the subdermal layer (12 positive samples), followed by the forceps (7 positive samples), the tip of the surgeon's glove (7 positive samples), the outside scalpel blade (4 positive samples), and the inside scalpel blade (1 positive sample). There were 27 of 75 swabs that were positive on culture for P. acnes in male patients compared with 4 of 125 swabs in female patients. Male patients had 66 times (95% confidence interval, 6 to 680 times) higher odds of having a positive culture indicating subdermal colonization compared with female patients (p < 0.001).
Conclusions:
P. acnes is a common contaminant of the surgical field in primary shoulder arthroplasty. The subdermal layer may be the source of this contamination, and the prevalence of P. acnes in the surgical wound may be due to the surgeon's manipulation with gloves and instruments. Our findings are consistent with those regarding the increased rates of P. acnes bacterial load and intraoperative growth in male patients compared with female patients.
Clinical Relevance:
P. acnes is likely to be spread throughout the surgical field from the subdermal layer via soft-tissue handling by the surgeon and instruments. Strategies need to be utilized to minimize this contact and to reduce the chance of colonization.
Insights
Propionibacterium acnes is a common contaminant in shoulder arthroplasty, often originating from the subdermal layer. Male patients showed significantly higher rates of P. acnes contamination compared to female patients.
Area of Science:
- Orthopedic Surgery
- Microbiology
- Infectious Disease
Background:
- Propionibacterium acnes (P. acnes) is frequently implicated in postoperative shoulder infections.
- While P. acnes is found in culture specimens during primary shoulder arthroplasty, its role as a pathogen versus contaminant is debated.
- Identifying sources of P. acnes contamination is crucial for preventing surgical site infections.
Purpose of the Study:
- To investigate the potential sources of P. acnes contamination during primary shoulder arthroplasty.
- To determine the prevalence and distribution of P. acnes in the surgical field.
- To explore demographic differences, specifically sex, in P. acnes colonization rates.
Main Methods:
- Tissue swabs were collected from five distinct sites during primary shoulder arthroplasty in 40 consecutive patients.
- Specimen sites included the subdermal layer, surgeon's glove tip, inside and outside scalpel blades, and forceps.
- Microbiological analysis was performed to identify P. acnes presence in each specimen.
Main Results:
- P. acnes was detected in at least one culture specimen from 33% of patients (13/40).
- The subdermal layer was the most frequent source of P. acnes (12 positive samples), followed by forceps and glove tips (7 each).
- Male patients exhibited significantly higher P. acnes positivity rates (73%) compared to female patients (8%), with male patients having 66 times higher odds of subdermal colonization.
Conclusions:
- P. acnes is a common contaminant in the surgical field during primary shoulder arthroplasty, likely originating from the subdermal layer.
- Surgeon's manipulation of soft tissues and instruments can spread P. acnes throughout the surgical site.
- Strategies to minimize contact and reduce colonization are necessary, with particular attention to potential sex-based differences in bacterial load.
