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Propionibacterium Acnes Infection of a Metacarpophalangeal Joint Arthroplasty
CASE REPOSITORY
Propionibacterium Acnes Infection of a Metacarpophalangeal Joint Arthroplasty Guillaume Bacle, MD, PhD,*†‡ Sheena K. Sikora, MD,§ Eugene T. H. Ek, MBBS, PhD§k{
Neglected and underestimated in the past, Propionibacterium acnes is currently the most prevalent organism associated with deep prosthetic infections around the shoulder. Surprisingly, it has never been reported as a cause of infection in the hand. Here we report a case of a late presentation of a P. acnes infection in a metacarpophalangeal joint replacement, resulting in chronic low-grade pain with movement. The patient underwent a 2-stage revision, with initial removal of the prosthesis. Positive cultures for P. acnes required 15 days of extended incubation. The patient subsequently had 6 weeks of oral antibiotics followed by a secondstage revision with a Silastic implant. (J Hand Surg Am. 2017;-(-):1.e1-e6. Copyright Ó 2017 by the American Society for Surgery of the Hand. All rights reserved.) Key words Propionibacterium acnes, infection, arthroplasty, metacarpophalangeal joint, revision.
P
gram-positive, none spore-forming, anaerobic and aerotolerant bacillus that resides preferentially within sebaceous follicles of the face, upper thorax, and axilla.1,2 Although it has been commonly recognized as a skin commensal bacteria, more recent studies within the shoulder literature, have reported that Propionibacterium acnes is the most prevalent pathogen involved in postoperative prosthetic shoulder infections, often associated with a high morbidity.3,4 Propionibacterium acnes is a fastidious slowgrowing organism that is often difficult to detect and ROPIONIBACTERIUM ACNES IS A
From the *The Bernard O’Brien Institute of Microsurgery, Fitzroy; the {Melbourne Orthopaedic Group, Windsor, Victoria; the §Division of Hand Surgery, Department of Orthopaedics, Dandenong Hospital; the kDepartment of Surgery, Monash Medical Centre, Monash University, Melbourne, Australia; the †Department of Orthopaedic Surgery, Hand Surgery Unit, Hôpital Trousseau; and the ‡UMR Imagerie et Cerveau, Université FrançoisRabelais, Tours, France.
associated with insidious and nonspecific clinical presentations.5 Microbiological detection of P. acnes requires incubation for at least 13 days, in anaerobic and aerobic culture conditions.1,6 Infections around the hand usually involve fast-growing gram-positive cocci bacteria such as Staphylococcus aureus or Streptococcus sp.7 Consequently, in the setting of postoperative hand infections, especially prosthetic infections, routine bacterial cultures of tissues and fluids are usually discarded after 5 days of incubation by most microbiological laboratories.2 Here we describe a rare case of an insidious metacarpophalangeal (MCP) joint periprosthetic infection due to P. acnes. In this report, we aim to raise awareness among hand surgeons about potential P. acnes infections following surgery around the hand.
Received for publication November 10, 2016; accepted in revised form January 27, 2017. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. The investigation was performed at the Melbourne Orthopaedic Group and Department of Orthopaedics, Dandenong Hospital, Monash University, Australia. Corresponding author: Guillaume Bacle, MD, PhD, The Bernard O’Brien Institute of Microsurgery, 42 Fitzroy St., Fitzroy, Victoria 3065, Australia; e-mail: bacle.guillaume@ wanadoo.fr. 0363-5023/17/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2017.01.023
CASE REPORT A 69-year-old right-handed retired man was referred to G.P.’s institution for evaluation of persistent lowgrade pain, swelling, and stiffness of his middle finger MCP joint. He had previously had a cemented unconstrained metal on polyethylene MCP arthroplasty (SR MCP, Small Bone Innovations, Inc., Morrisville, PA) for primary osteoarthritis performed
Ó 2017 ASSH
r
Published by Elsevier, Inc. All rights reserved.
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P. ACNES INFECTION OF MCP JOINT ARTHROPLASTY
FIGURE 1: Plain radiographs demonstrate a third MCP prosthesis with discrete periprosthetic radiolucency. A Posteroanterior, B oblique, and C lateral views show osteolysis located between the head-neck junction of the metacarpal component and the bone (yellow arrows). A, B, Bone erosion is seen around the volar-radial cortex of the phalanx (red arrows).
3 years earlier at an outside institution. His only significant past medical history included type 2 diabetes for which he was taking metformin. Despite a seemingly uneventful recovery from the index surgery, the patient never experienced complete symptomatic relief and stated that the swelling around the MCP joint never completely resolved. He also reported recurrent swelling with use of the finger and activity-related pain. Clinical examination demonstrated a well-healed surgical scar over the dorsal aspect of the MCP joint of the middle finger. The skin was not erythematous and there were no signs of an acute infection. The MCP joint was mildly swollen and his range of motion was 10 to 45 with moderate irritability at the end ranges. He had normal proximal and distal interphalangeal joint motion. X-Rays of the middle finger demonstrated periprosthetic loosening of the metacarpal component, particularly around the head-neck junction (Fig. 1). The phalangeal component appeared to be well-fixed, but there was suggestion of slight erosion of the radiopalmar cortex of the proximal phalanx. Given the likelihood of either aseptic loosening or lowgrade periprosthetic infection, a bone scintigraphy using single-photon emission computed tomography scan was performed. This investigation combines a technetium-99melabelled methylene diphosphonate bone scan with a computed tomography scan for bony localization. On dynamic-flow images, the bone J Hand Surg Am.
scan showed increased vascularity with focal hyperemia surrounding the proximal and distal aspect of the MCP joint prosthesis corresponding to an increased osteoblastic activity displayed on the delayed images (Fig. 2). Inflammatory markers were performed; however, these did not demonstrate any increase in white cell count, C-reactive protein or erythrocyte sedimentation rate. Given the clinical history and the imaging findings, in particular the increased osteoblastic activity surrounding the joint replacement, a low-grade deep periprosthetic infection was considered the most likely cause of the ongoing symptoms. Consequently, the patient underwent a 2-stage revision of this MCP joint replacement. During the first-stage procedure, when entering the MCP joint, the surrounding tissue and the joint capsule appeared indurated and oedematous. However, no evidence of pus was noted. Multiple swabs and tissue specimens were obtained for microbiological analysis. The prosthesis was then removed. The metacarpal component was explanted without much effort; however, the phalangeal component, which was well-fixed, required the use of flexible osteotomes to mobilize the prosthesis. The surrounding cement mantle was also removed with the use of osteotomes. Of note, when the metacarpal component was removed, note was made of a thin film that lined the intramedullary canal. This was curetted and also sent for microbiological analysis. Special note was made to have the period of cultures r
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P. ACNES INFECTION OF MCP JOINT ARTHROPLASTY
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FIGURE 2: Bone scan performed with single-photon emission computed tomography scan of both hands. A Dorsal and B volar blood pool images show focal increased vascularity around the MCP prosthesis, consistent with localized inflammation. C Dorsal and D volar delayed images exhibit increased osteoblastic activity around the MCP prosthesis.
extended to at least 2 weeks to exclude the presence of P. acnes. Following removal of the prosthesis, an articulating cement spacer comprising 1 mix of Palacos RþG bone cement (Heraeus Kulzer GmbH, Hanau, Germany) with 500 mg of vancomycin was fashioned to keep the MCP joint out to length and to also allow the patient to mobilize the middle finger prior to the second-stage procedure. (Figs. 3, 4). After surgery, the patient was empirically treated with oral cephalexin and allowed gentle motion of the finger with a resting orthosis. Although initial cultures were negative for bacterial growth, after 15 days of incubation P. acnes, sensitive to penicillin G, vancomycin, and clindamycin, was cultured from the deep periprosthetic tissue samples. After consultation with an infectious diseases
J Hand Surg Am.
FIGURE 3: Explanted MCP joint prosthesis and the “custom” made antibiotic cement spacer.
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P. ACNES INFECTION OF MCP JOINT ARTHROPLASTY
FIGURE 4: A First-stage revision with antibiotic cement MCP spacer in situ. B Posteroanterior radiograph shows the implanted antibiotic cement spacer.
FIGURE 5: Postoperative plain radiographs following the second-stage revision with a Silastic MCP joint arthroplasty at 6 months of follow-up. A Posteroanterior, B oblique, and C lateral views show the implant in good position.
physician, the patient was commenced on 4 weeks of oral clindamycin. A second-stage revision MCP joint replacement was performed 6 weeks after the first-stage procedure. The patient underwent removal of the cement spacer and implantation of a Silastic MCP implant J Hand Surg Am.
(NeuFlex; DePuy Synthes Companies, Mulgrave, Victoria, Australia) (Fig. 5). The patient made an excellent recovery, and at 6 months after surgery, he was pain-free and had a range of motion of 10 to 70 and a tip to palm distance of approximately 5 mm (Fig. 6). r
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FIGURE 6: Postoperative range of motion of the middle finger MCP joint at 6 months of follow-up after the second-stage revision. A Posterior and B lateral views demonstrate full active extension with a lag of 10 . C Clenched fist with approximately 5 mm tip to palm distance.
DISCUSSION Despite increasing concern regarding the incidence of P. acnes in periprosthetic infection in the shoulder,3,4 this pathogen remains surprisingly unreported in infections around the hand.2 Because the predominant location of this bacteria is around the axilla, this explains the relatively high incidence in shoulder infections.1 Nevertheless, P. acnes infections have been reported in other sites around the body, with Lutz et al8 describing deep lower limb arthroplasty infections with P. acnes. However, the true incidence of this low-grade, fastidious infection is largely unknown because microbiological detection requires specific extended cultures. This case highlights the need to consider P. acnes in cases of potential insidious and delayed periprosthetic infections. Although P. acnes has been described as a nonpathogenic skin commensal bacillus,1 isolation of P. acnes in a bacteriological sample from a foreign body (prosthesis or hardware) should not be considered as simple contamination.4 As such, hand surgeons must be aware of its potential pathological involvement. Obviously, these results should be taken into consideration with the clinical presentation. As previously described, patients with P. acnes infections often have low-grade and nonspecific symptoms,5 as seen in our present case who demonstrated only low-grade pain and limitations of range of motion. Indeed, as shown by Lutz et al,8 obtaining positive cultures is highly dependent on the quality of the samples taken and the methodology used by the microbiology laboratory to isolate this bacterium. In the present case report, the extended cultures of 2 samples of periprosthetic tissue around the implant led to the bacterial identification because tissue from within the joint were negative. These findings J Hand Surg Am.
could be explained by the production of a biofilm at the surface of inert structures by P. acnes.9 This biofilm isolates the bacteria from the environment and allows it to proliferate on the surface of the prosthesis and to escape the action of antibiotics. Therefore, in order to successfully treat this infection, this biofilm needs to be completely removed with the prosthesis, including cement mantle.10 In conclusion, hand surgeons need to be aware of possibility of P. acnes infection in hand surgery, especially when they are faced with patients with unexplained low-grade pain and swelling following joint replacement surgery. If suspected, tissue samples around the prosthesis should be cultured for at least 2 weeks and the laboratory should be made aware of the potential for P. acnes growth. In this case, removal of the prosthesis and appropriate antibiotic treatment was successful in curing the infection. REFERENCES 1. Achermann Y, Goldstein EJ, Coenye T, Shirtliff ME. Propionibacterium acnes: from commensal to opportunistic biofilmassociated implant pathogen. Clin Microbiol Rev. 2014;27(3): 419e440. 2. Horneff JG, Hsu JE, Huffman GR. Propionibacterium acnes infections in shoulder surgery. Orthop Clin North Am. 2014;45(4): 515e521. 3. Kelly JD II, Hobgood ER. Positive culture rate in revision shoulder arthroplasty. Clin Orthop Relat Res. 2009;467(9): 2343e2348. 4. Levy PY, Fenollar F, Stein A, et al. Propionibacterium acnes postoperative shoulder arthritis: an emerging clinical entity. Clin Infect Dis. 2008;46(12):1884e1886. 5. Millett PJ, Yen YM, Price CS, Horan MP, van der Meijden OA, Elser F. Propionibacterium acnes infection as an occult case of postoperative shoulder pain: a case series. Clin Orthop Relat Res. 2011;469(10):2824e2830. 6. Butler-Wu SM, Burns EM, Pottinger PS, et al. Optimization of periprosthetic culture for diagnosis of Propionibacterium acnes prosthetic joint infection. J Clin Microbiol. 2011;49(7):2490e2495.
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P. ACNES INFECTION OF MCP JOINT ARTHROPLASTY
7. Houshian S, Seyedipour S, Wedderkopp N. Epidemiology of bacterial hand infections. Int J Infect Dis. 2006;10(4): 315e319. 8. Lutz MF, Berthelot P, Fresard A, et al. Arthroplastic and osteosynthetic infections due to Propionibacterium acnes: a retrospective study of 52 cases, 1995e2002. Eur J Clin Microbiol Infect Dis. 2005;24(11):739e744.
J Hand Surg Am.
9. Holmberg A, Lood R, Mörgelin M, et al. Biofilm formation by Propionibacterium acnes is a characteristic of invasive isolates. Clin Microbiol Infect. 2009;15(8):787e795. 10. Bayston R, Ashraf W, Barker-Davies R, et al. Biofilm formation by Propionibacterium acnes on biomaterials in vitro and in vivo: impact on diagnosis and treatment. J Biomed Mater Res A. 2007;81(3): 705e709.
r
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Propionibacterium Acnes Infection of a Metacarpophalangeal Joint Arthroplasty Guillaume Bacle, MD, PhD,*†‡ Sheena K. Sikora, MD,§ Eugene T. H. Ek, MBBS, PhD§k{
Neglected and underestimated in the past, Propionibacterium acnes is currently the most prevalent organism associated with deep prosthetic infections around the shoulder. Surprisingly, it has never been reported as a cause of infection in the hand. Here we report a case of a late presentation of a P. acnes infection in a metacarpophalangeal joint replacement, resulting in chronic low-grade pain with movement. The patient underwent a 2-stage revision, with initial removal of the prosthesis. Positive cultures for P. acnes required 15 days of extended incubation. The patient subsequently had 6 weeks of oral antibiotics followed by a secondstage revision with a Silastic implant. (J Hand Surg Am. 2017;-(-):1.e1-e6. Copyright Ó 2017 by the American Society for Surgery of the Hand. All rights reserved.) Key words Propionibacterium acnes, infection, arthroplasty, metacarpophalangeal joint, revision.
P
gram-positive, none spore-forming, anaerobic and aerotolerant bacillus that resides preferentially within sebaceous follicles of the face, upper thorax, and axilla.1,2 Although it has been commonly recognized as a skin commensal bacteria, more recent studies within the shoulder literature, have reported that Propionibacterium acnes is the most prevalent pathogen involved in postoperative prosthetic shoulder infections, often associated with a high morbidity.3,4 Propionibacterium acnes is a fastidious slowgrowing organism that is often difficult to detect and ROPIONIBACTERIUM ACNES IS A
From the *The Bernard O’Brien Institute of Microsurgery, Fitzroy; the {Melbourne Orthopaedic Group, Windsor, Victoria; the §Division of Hand Surgery, Department of Orthopaedics, Dandenong Hospital; the kDepartment of Surgery, Monash Medical Centre, Monash University, Melbourne, Australia; the †Department of Orthopaedic Surgery, Hand Surgery Unit, Hôpital Trousseau; and the ‡UMR Imagerie et Cerveau, Université FrançoisRabelais, Tours, France.
associated with insidious and nonspecific clinical presentations.5 Microbiological detection of P. acnes requires incubation for at least 13 days, in anaerobic and aerobic culture conditions.1,6 Infections around the hand usually involve fast-growing gram-positive cocci bacteria such as Staphylococcus aureus or Streptococcus sp.7 Consequently, in the setting of postoperative hand infections, especially prosthetic infections, routine bacterial cultures of tissues and fluids are usually discarded after 5 days of incubation by most microbiological laboratories.2 Here we describe a rare case of an insidious metacarpophalangeal (MCP) joint periprosthetic infection due to P. acnes. In this report, we aim to raise awareness among hand surgeons about potential P. acnes infections following surgery around the hand.
Received for publication November 10, 2016; accepted in revised form January 27, 2017. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. The investigation was performed at the Melbourne Orthopaedic Group and Department of Orthopaedics, Dandenong Hospital, Monash University, Australia. Corresponding author: Guillaume Bacle, MD, PhD, The Bernard O’Brien Institute of Microsurgery, 42 Fitzroy St., Fitzroy, Victoria 3065, Australia; e-mail: bacle.guillaume@ wanadoo.fr. 0363-5023/17/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2017.01.023
CASE REPORT A 69-year-old right-handed retired man was referred to G.P.’s institution for evaluation of persistent lowgrade pain, swelling, and stiffness of his middle finger MCP joint. He had previously had a cemented unconstrained metal on polyethylene MCP arthroplasty (SR MCP, Small Bone Innovations, Inc., Morrisville, PA) for primary osteoarthritis performed
Ó 2017 ASSH
r
Published by Elsevier, Inc. All rights reserved.
r
1.e1
1.e2
P. ACNES INFECTION OF MCP JOINT ARTHROPLASTY
FIGURE 1: Plain radiographs demonstrate a third MCP prosthesis with discrete periprosthetic radiolucency. A Posteroanterior, B oblique, and C lateral views show osteolysis located between the head-neck junction of the metacarpal component and the bone (yellow arrows). A, B, Bone erosion is seen around the volar-radial cortex of the phalanx (red arrows).
3 years earlier at an outside institution. His only significant past medical history included type 2 diabetes for which he was taking metformin. Despite a seemingly uneventful recovery from the index surgery, the patient never experienced complete symptomatic relief and stated that the swelling around the MCP joint never completely resolved. He also reported recurrent swelling with use of the finger and activity-related pain. Clinical examination demonstrated a well-healed surgical scar over the dorsal aspect of the MCP joint of the middle finger. The skin was not erythematous and there were no signs of an acute infection. The MCP joint was mildly swollen and his range of motion was 10 to 45 with moderate irritability at the end ranges. He had normal proximal and distal interphalangeal joint motion. X-Rays of the middle finger demonstrated periprosthetic loosening of the metacarpal component, particularly around the head-neck junction (Fig. 1). The phalangeal component appeared to be well-fixed, but there was suggestion of slight erosion of the radiopalmar cortex of the proximal phalanx. Given the likelihood of either aseptic loosening or lowgrade periprosthetic infection, a bone scintigraphy using single-photon emission computed tomography scan was performed. This investigation combines a technetium-99melabelled methylene diphosphonate bone scan with a computed tomography scan for bony localization. On dynamic-flow images, the bone J Hand Surg Am.
scan showed increased vascularity with focal hyperemia surrounding the proximal and distal aspect of the MCP joint prosthesis corresponding to an increased osteoblastic activity displayed on the delayed images (Fig. 2). Inflammatory markers were performed; however, these did not demonstrate any increase in white cell count, C-reactive protein or erythrocyte sedimentation rate. Given the clinical history and the imaging findings, in particular the increased osteoblastic activity surrounding the joint replacement, a low-grade deep periprosthetic infection was considered the most likely cause of the ongoing symptoms. Consequently, the patient underwent a 2-stage revision of this MCP joint replacement. During the first-stage procedure, when entering the MCP joint, the surrounding tissue and the joint capsule appeared indurated and oedematous. However, no evidence of pus was noted. Multiple swabs and tissue specimens were obtained for microbiological analysis. The prosthesis was then removed. The metacarpal component was explanted without much effort; however, the phalangeal component, which was well-fixed, required the use of flexible osteotomes to mobilize the prosthesis. The surrounding cement mantle was also removed with the use of osteotomes. Of note, when the metacarpal component was removed, note was made of a thin film that lined the intramedullary canal. This was curetted and also sent for microbiological analysis. Special note was made to have the period of cultures r
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FIGURE 2: Bone scan performed with single-photon emission computed tomography scan of both hands. A Dorsal and B volar blood pool images show focal increased vascularity around the MCP prosthesis, consistent with localized inflammation. C Dorsal and D volar delayed images exhibit increased osteoblastic activity around the MCP prosthesis.
extended to at least 2 weeks to exclude the presence of P. acnes. Following removal of the prosthesis, an articulating cement spacer comprising 1 mix of Palacos RþG bone cement (Heraeus Kulzer GmbH, Hanau, Germany) with 500 mg of vancomycin was fashioned to keep the MCP joint out to length and to also allow the patient to mobilize the middle finger prior to the second-stage procedure. (Figs. 3, 4). After surgery, the patient was empirically treated with oral cephalexin and allowed gentle motion of the finger with a resting orthosis. Although initial cultures were negative for bacterial growth, after 15 days of incubation P. acnes, sensitive to penicillin G, vancomycin, and clindamycin, was cultured from the deep periprosthetic tissue samples. After consultation with an infectious diseases
J Hand Surg Am.
FIGURE 3: Explanted MCP joint prosthesis and the “custom” made antibiotic cement spacer.
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P. ACNES INFECTION OF MCP JOINT ARTHROPLASTY
FIGURE 4: A First-stage revision with antibiotic cement MCP spacer in situ. B Posteroanterior radiograph shows the implanted antibiotic cement spacer.
FIGURE 5: Postoperative plain radiographs following the second-stage revision with a Silastic MCP joint arthroplasty at 6 months of follow-up. A Posteroanterior, B oblique, and C lateral views show the implant in good position.
physician, the patient was commenced on 4 weeks of oral clindamycin. A second-stage revision MCP joint replacement was performed 6 weeks after the first-stage procedure. The patient underwent removal of the cement spacer and implantation of a Silastic MCP implant J Hand Surg Am.
(NeuFlex; DePuy Synthes Companies, Mulgrave, Victoria, Australia) (Fig. 5). The patient made an excellent recovery, and at 6 months after surgery, he was pain-free and had a range of motion of 10 to 70 and a tip to palm distance of approximately 5 mm (Fig. 6). r
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FIGURE 6: Postoperative range of motion of the middle finger MCP joint at 6 months of follow-up after the second-stage revision. A Posterior and B lateral views demonstrate full active extension with a lag of 10 . C Clenched fist with approximately 5 mm tip to palm distance.
DISCUSSION Despite increasing concern regarding the incidence of P. acnes in periprosthetic infection in the shoulder,3,4 this pathogen remains surprisingly unreported in infections around the hand.2 Because the predominant location of this bacteria is around the axilla, this explains the relatively high incidence in shoulder infections.1 Nevertheless, P. acnes infections have been reported in other sites around the body, with Lutz et al8 describing deep lower limb arthroplasty infections with P. acnes. However, the true incidence of this low-grade, fastidious infection is largely unknown because microbiological detection requires specific extended cultures. This case highlights the need to consider P. acnes in cases of potential insidious and delayed periprosthetic infections. Although P. acnes has been described as a nonpathogenic skin commensal bacillus,1 isolation of P. acnes in a bacteriological sample from a foreign body (prosthesis or hardware) should not be considered as simple contamination.4 As such, hand surgeons must be aware of its potential pathological involvement. Obviously, these results should be taken into consideration with the clinical presentation. As previously described, patients with P. acnes infections often have low-grade and nonspecific symptoms,5 as seen in our present case who demonstrated only low-grade pain and limitations of range of motion. Indeed, as shown by Lutz et al,8 obtaining positive cultures is highly dependent on the quality of the samples taken and the methodology used by the microbiology laboratory to isolate this bacterium. In the present case report, the extended cultures of 2 samples of periprosthetic tissue around the implant led to the bacterial identification because tissue from within the joint were negative. These findings J Hand Surg Am.
could be explained by the production of a biofilm at the surface of inert structures by P. acnes.9 This biofilm isolates the bacteria from the environment and allows it to proliferate on the surface of the prosthesis and to escape the action of antibiotics. Therefore, in order to successfully treat this infection, this biofilm needs to be completely removed with the prosthesis, including cement mantle.10 In conclusion, hand surgeons need to be aware of possibility of P. acnes infection in hand surgery, especially when they are faced with patients with unexplained low-grade pain and swelling following joint replacement surgery. If suspected, tissue samples around the prosthesis should be cultured for at least 2 weeks and the laboratory should be made aware of the potential for P. acnes growth. In this case, removal of the prosthesis and appropriate antibiotic treatment was successful in curing the infection. REFERENCES 1. Achermann Y, Goldstein EJ, Coenye T, Shirtliff ME. Propionibacterium acnes: from commensal to opportunistic biofilmassociated implant pathogen. Clin Microbiol Rev. 2014;27(3): 419e440. 2. Horneff JG, Hsu JE, Huffman GR. Propionibacterium acnes infections in shoulder surgery. Orthop Clin North Am. 2014;45(4): 515e521. 3. Kelly JD II, Hobgood ER. Positive culture rate in revision shoulder arthroplasty. Clin Orthop Relat Res. 2009;467(9): 2343e2348. 4. Levy PY, Fenollar F, Stein A, et al. Propionibacterium acnes postoperative shoulder arthritis: an emerging clinical entity. Clin Infect Dis. 2008;46(12):1884e1886. 5. Millett PJ, Yen YM, Price CS, Horan MP, van der Meijden OA, Elser F. Propionibacterium acnes infection as an occult case of postoperative shoulder pain: a case series. Clin Orthop Relat Res. 2011;469(10):2824e2830. 6. Butler-Wu SM, Burns EM, Pottinger PS, et al. Optimization of periprosthetic culture for diagnosis of Propionibacterium acnes prosthetic joint infection. J Clin Microbiol. 2011;49(7):2490e2495.
r
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P. ACNES INFECTION OF MCP JOINT ARTHROPLASTY
7. Houshian S, Seyedipour S, Wedderkopp N. Epidemiology of bacterial hand infections. Int J Infect Dis. 2006;10(4): 315e319. 8. Lutz MF, Berthelot P, Fresard A, et al. Arthroplastic and osteosynthetic infections due to Propionibacterium acnes: a retrospective study of 52 cases, 1995e2002. Eur J Clin Microbiol Infect Dis. 2005;24(11):739e744.
J Hand Surg Am.
9. Holmberg A, Lood R, Mörgelin M, et al. Biofilm formation by Propionibacterium acnes is a characteristic of invasive isolates. Clin Microbiol Infect. 2009;15(8):787e795. 10. Bayston R, Ashraf W, Barker-Davies R, et al. Biofilm formation by Propionibacterium acnes on biomaterials in vitro and in vivo: impact on diagnosis and treatment. J Biomed Mater Res A. 2007;81(3): 705e709.
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