title: Subclinical (biofilm) infection causes capsular contracture in a porcine model following augmentation mammaplasty.
abstract: BACKGROUND
  Capsular contracture remains the most common complication following augmentation mammaplasty. The infective hypothesis implicates subclinical infection with biofilm in its pathogenesis. The authors developed an in vivo model of subclinical infection and biofilm formation to further investigate this.
  
  
  METHODS
  Adult female pigs underwent augmentation mammaplasty using miniature gel-filled implants. Staphylococcus epidermidis was inoculated into some of the periprosthetics as compared with control pockets, which were not inoculated. Implants were left in situ for 13 weeks, after which clinical assessment with the Baker technique was performed. Implants and capsules were then removed and subjected to laboratory analysis to detect biofilm.
  
  
  RESULTS
  Fifty-one breast augmentations were performed in six pigs: 36 in submammary pockets inoculated with S. epidermidis and 15 in uninoculated pockets. Twenty-six of the 36 inoculated implants (72.2 percent) resulted in biofilm production. Pocket inoculation was strongly associated with biofilm formation (p = 0.0095). The presence of biofilm in the inoculated pockets was also significantly associated with the subsequent development of capsular contracture as compared with the uninoculated pockets (p < 0.05). Of the 15 uninoculated pockets, seven developed contracture. Five of these, however, demonstrated the presence of biofilm caused by native porcine S. epidermidis. Of the 31 biofilm-positive specimens, 25 (80.6 percent) developed capsular contracture. Using univariate analysis, biofilm formation was associated with a fourfold increased risk of developing contracture (odds ratio, 4.1667; 95 percent confidence interval, 1.1939 to 14.5413).
  
  
  CONCLUSIONS
  Using this in vivo model, the authors have demonstrated a causal link between subclinical infection, biofilm formation, and capsular contracture.
authors.affiliation: Sydney, New South Wales, Australia From the Surgical Infection Research Group, South Western Sydney Clinical School, University of New South Wales, and the Department of Plastic and Maxillofacial Surgery, Liverpool Hospital.
authors.forename: Henny
authors.initials: H
authors.lastname: Tamboto
authors.forename: Karen
authors.initials: K
authors.lastname: Vickery
authors.forename: Anand K
authors.initials: AK
authors.lastname: Deva
mesh_terms: D000818:Animals; D018441:Biofilms; D001941:Breast Diseases / Q000382:microbiology*; D019928:Breast Implantation / Q000009:adverse effects*; D018427:Breast Implants / Q000009:adverse effects*; D004195:Disease Models, Animal; D005260:Female; D016459:Prosthesis-Related Infections / Q000150:complications* / Q000453:epidemiology / Q000209:etiology; D013203:Staphylococcal Infections / Q000150:complications* / Q000453:epidemiology / Q000209:etiology; D013212:Staphylococcus epidermidis; D013552:Swine
references.citation: Silverman BG, Brown SL, Bright RA, Kaczmarek RG, Arrowsmith-Lowe JB, Kessler DA. Reported complications of silicone gel breast implants: An epidemiologic review. Ann Intern Med. 1996;124:744–756.
references.citation: Kjøller K, Hölmich LR, Jacobsen PH, et al. Epidemiological investigation of local complications after cosmetic breast implant surgery in Denmark. Ann Plast Surg. 2002;48:229–237.
references.citation: Araco A, Gravante G, Araco F, Delogu D, Cervelli V. Capsular contracture: Results of 3002 patients with aesthetic breast augmentation. Plast Reconstr Surg. 2006;118:1499–1500.
references.citation: Burkhardt BR, Fried M, Schnur PL, Tofield JJ. Capsules, infection, and intraluminal antibiotics. Plast Reconstr Surg. 1981;68:43–49.
references.citation: Shah Z, Lehman JA Jr, Tan J. Does infection play a role in breast capsular contracture? Plast Reconstr Surg. 1981;68:34–42.
references.citation: Virden CP, Dobke MK, Stein P, Parsons CL, Frank DH. Subclinical infection of the silicone breast implant surface as a possible cause of capsular contracture. Aesthetic Plast Surg. 1992;16:173–179.
references.citation: Pajkos A, Deva AK, Vickery K, Cope C, Chang L, Cossart YE. Detection of subclinical infection in significant breast implant capsules. Plast Reconstr Surg. 2003;111:1605–1611.
references.citation: O'Gara JP, Humphreys H. Staphylococcus epidermidis biofilms: Importance and implications. J Med Microbiol. 2001;50:582–587.
references.citation: Donlan RM. Biofilms and device-associated infections. Emerg Infect Dis. 2001;7:277–281.
references.citation: Costerton JW. Biofilm theory can guide the treatment of device-related orthopaedic infections. Clin Orthop Relat Res. 2005;437:7–11.
references.citation: Tunney MM, Dunne N, Einarsson G, McDowell A, Kerr A, Patrick S. Biofilm formation by bacteria isolated from retrieved failed prosthetic hip implants in an in vitro model of hip arthroplasty antibiotic prophylaxis. J Orthop Res. 2007;25:2–10.
references.citation: Vinh DC, Embil JM. Device-related infections: A review. J Long Term Eff Med Implants 2005;15:467–488.
references.citation: Costerton JW, Montanaro L, Arciola CR. Biofilm in implant infections: Its production and regulation. Int J Artif Organs 2005;28:1062–1068.
references.citation: Donlan RM. Role of biofilms in antimicrobial resistance. ASAIO J. 2000;46:S47–S57.
references.citation: Donlan RM. Biofilm formation: A clinically relevant microbiological process. Clin Infect Dis. 2001;33:1387–1392.
references.citation: Gilbert P, Das JR, Jones MV, Allison DG. Assessment of resistance towards biocides following the attachment of micro-organisms to, and growth on, surfaces. J Appl Microbiol. 2001;91:248–154.
references.citation: Courtiss EH, Goldwyn RM, Anastasi GW. The fate of breast implants with infections around them. Plast Reconstr Surg. 1979;63:812–816.
references.citation: Collis N, Coleman D, Foo IT, Sharpe DT. Ten-year review of a prospective randomized controlled trial of textured versus smooth subglandular silicone gel breast implants. Plast Reconstr Surg. 2000;106:786–791.
references.citation: Adams WP Jr, Rios JL, Smith SJ. Enhancing patient outcomes in aesthetic and reconstructive breast surgery using triple antibiotic breast irrigation: Six-year prospective clinical study. Plast Reconstr Surg. 2006;118:46S–52S.
references.citation: Dobbins JJ, Seligson D, Raff MJ. Bacterial colonisation of orthopaedic devices in the absence of clinical infection. J Infect Dis. 1988;158:203.
references.citation: Tunney MM, Patrick S, Curran MD, et al. Detection of prosthetic hip infection at revision arthroplasty by immunofluorescence microscopy and PCR amplification of the bacterial 16S rRNA gene. J Clin Microbiol. 1999;37:3281–3290.
references.citation: Kossovsky N, Heggers JP, Parsons RW, Robson MC. Analysis of the surface morphology of recovered silicone mammary implants. Plast Reconstr Surg. 1983;71:795–804.
references.citation: Burkhardt BR, Dempsey PD, Schnur PL, Tofield JJ. Capsular contracture: A prospective study of the effect of local antibacterial agents. Plast Reconstr Surg. 1986;77:919–932.
references.citation: Rudolph R, Woodward M. Absence of visible bacteria in capsules around silicone breast implants. Plast Reconstr Surg. 1983;72:32–37.
references.citation: Alfano C, Mazzocchi M, Scuderi N. Mammary compliance: An objective measurement of capsular contracture. Aesthetic Plast Surg. 2004;28:75–79.