SHOULDER SURGERY AND PROPIONIBACTERIUM ACNES (P. ACNES) BACTERIA
Terry L. Whipple, M.D., F.A.C.S.
About P. acnes
P. acnes is a rod-shaped, anaerobic (but oxygen tolerant) bacteria that develops in
low oxygen environments such as hair follicles and deep within pores – Figure 1. It
is closely linked with the commonly known “acne” skin condition, and is
therefore prevalent on the shoulders, as well as the neck and face.
Figure 1. P. acnes bacteria
Additionally, P. acnes is gram-positive, meaning it turns violet during the Gram
staining method of bacterial determination – Figure 2. Fortunately, its grampositive nature makes P. acnes more vulnerable to antibiotics.
Figure 2. Gram Staining of
P. acnes Bacteria
P. acnes shoulder infections
P. acnes shoulder infections are generally similar in their manifestation. The slow growth
of the bacteria results in late-stage infections with frequently negative cultures1. To
identify P. acnes, studies normally recommend culture incubation for 14 to 28-days2.
Infection appears 3-7
weeks after surgery
Initial bacterial
cultures are negative
Not necessarily
Figure 3. How a P. acnes shoulder infection generally manifests
Extraordinarily slow growing
Peer-reviewed studies demonstrate infection rates between 2% and 7.8% for most shoulder
procedures3-6. In these procedures, P. acnes is one of the three most commonly found bacteria7.
However, the time taken to positively identify P. acnes through a culture is significantly longer than the
other two bacteria – Table 1.
Bacteria
Staphylococcus aureus (Staph)
Staphylococcus epidermidis (Staph)
Propionibacterium acnes (P. acnes)
Culture Time to Positively Identify
2 hours to 4 days8
10 to 24 hours9
Minimum of 13-days in anaerobic environment10
Table 1
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Managing P. acnes
Peer-reviewed literature suggests the following measures for reducing incidence of P. acnes infections:
•
•
•
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Prepare the surgical site several times with ChloraPrep® (or other chlorhexidine
solution)11
Perform routine intraoperative cultures and incubate for 28 days2
Administer antibiotics for sustained periods upon observing signs of inflammatory
reaction12
Incise and drain any fluctuant process, or skin swab re-culture without fluctuance
without necessarily removing the implant, if possible13
References
1. Pierre Yves Levy, et al. Propionibacterium acnes Postoperative Shoulder Arthritis: An Emerging
Clinical Entity Clin Infect Dis. Jun 2008
2. Sethi, Vadasdi, Greene, et al. Incidence of positive P. acnes in shoulder arthroscopy. AOSSM Poster
2014
3. Leroux T et al. Rate of and risk factors for reoperation after ORIF of midshaft clavicle fractures. JBJS
July 2014 (2.6% deep infection)
4. Blonna D. Incidence and risk factors for acute infection after prox hum fx. JSES April 2014 (4%
infection)
5. Liu PC et al. Infection after surgical reconstruction of a clavicle fracture using a recon plate. J Med
Sci Jan 2008 – Infection after surg recon of clavicle (4.9% infection)
6. Bostman, et al. Complications of plates in midclavicular fractures. J Trauma. Nov 1997 (7.8% deep
infection)
7. Saltzman MD et al. Infection after shoulder surgery. J Am Acad Orthop Surg. Apr 2011
8. Paule M. Detection of Staphylococcus aureus using real-time PCR. JMD Aug 2004
9. Haimi-Cohen Y, et al. Initial concentration of Staph in pediatric blood cultures. J Clin Microbiol. Mar
2002
10. Butler-Wu S, et al. Anaerobic thioglycolate broth culture for recovery of P. acnes. J Clin Microbiol.
Jul 2011
11. Edmiston CE Jr, et al. Reducing risk of surgical site infections: does chlorhexidine provide a benefit?
Am J Infect Control. May 2013
12. Portillo M, et al. Propionibacterium acnes: an underestimated pathogen in implant-associated
infections. Biomed Res Int. 2013
13. M. Nisbet. P. acnes: an under-appreciated cause of post-neurosurgical infection. J Antimicrobial
Chemother. Sep 2007
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