Basic Science
Presence of Propionibacterium acnes in primary shoulder arthroscopy: results of aspiration and tissue cultures

https://doi.org/10.1016/j.jse.2014.09.042Get rights and content

Background

Infection after shoulder surgery has a serious impact on patient outcome and costs associated with care. Propionibacterium acnes infection may be insidious and manifest years after index surgery with resultant joint arthropathy or prosthesis infection. Our goal was to evaluate the presence of P. acnes in a group of patients undergoing primary arthroscopic shoulder surgery to better understand this organism.

Methods

Samples were collected from 57 patients undergoing first-time shoulder arthroscopy. Demographic data and medical comorbidities were collected. A control, 2 skin swabs, synovial fluid, and 3 tissue samples were obtained. All samples were placed on aerobic plates, on anaerobic plates, and in thioglycolate broth and held for 28 days.

Results

Fifty-seven patients underwent arthroscopic shoulder surgery. The mean age was 51 years. Eighty-one samples (21.8%) were positive for P. acnes when cultures were held 14 days; 32 subjects (56%) had at least 1 culture that grew P. acnes. Positive skin cultures for P. acnes increased from 15.8% before incision to 40.4% at closure. This was even more pronounced in men as positive skin cultures increased from 31.3% before incision to 63.0% at closure. Thirteen patients (22.8%) had more than 3 cultures positive. None of the patients in this study have had signs or symptoms to suggest clinical P. acnes infection.

Conclusions

Of all subjects studied, 56% had at least 1 positive culture; 21% (of all 371 culture specimens obtained) grew P. acnes. We suspect that it is a consequence of true positive cultures from imperfect skin preparation and dermal contamination.

Section snippets

Materials and methods

Sterile skin swabs, aspirated joint fluid, and tissue specimens were collected from June 2013 to September 2013 from 57 patients undergoing shoulder arthroscopy without any previous shoulder surgery. Demographic data, visual analog scale (VAS) for pain, and medical comorbidities were also collected. Our inclusion criterion was shoulder disease necessitating primary shoulder arthroscopy. Our exclusion criteria were previous shoulder surgery and antibiotic treatment within 4 weeks before surgery.

Results

This study included 57 patients. There were 32 men (56.1%) and 25 women (43.9%). The mean age of the patients was 51 years (range, 17-81 years). Eleven patients reported osteoarthritis of joints other than the shoulder, 3 were current smokers or had a history of smoking, 4 had type 2 diabetes mellitus, and 8 were obese. Fifty-six percent of subjects had not had a cortisone injection on the surgical shoulder before surgery, and 44% had either 1 or more cortisone injections on the operative

Discussion

Infection after shoulder surgery has a serious impact on patient outcome and costs associated with care. P. acnes infection may be insidious and manifest years after index surgery with resultant joint arthropathy or prosthesis infection.13 Our goal was to investigate the presence of P. acnes, specifically how often cultures would become positive, in a group of patients undergoing primary arthroscopic shoulder surgery. We found a high rate of positive cultures for P. acnes; 56% of subjects had

Conclusions

Of all individuals studied, 56% had at least 1 positive culture for P. acnes. P. acnes was identified in 21.8% of 371 culture specimens obtained, including skin swab, synovial fluid aspiration, and tissue biopsy in a cohort of subjects without previous surgery or arthritis of the glenohumeral joint. Despite skin preparation and preoperative antibiotics, patients undergoing shoulder arthroscopy are exposed to and inoculated with P. acnes, likely from contamination of the joint with residual

Disclaimer

The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.

Acknowledgments

The authors thank Steve Delaronde for statistical analysis, Richie Fuld for help with IRB application and Greenwich Hospital microbiology laboratory for identifying bacterial presence on the samples.

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    The Greenwich Hospital Institutional Review Board approved this study: No. 2013006.

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