Detection of Bacterial Biofilm in Double Capsule Surrounding Mammary Implants

Sir:FigureThe finding of a double capsule surrounding breast implants is a recognized complication of breast augmentation surgery. In a recent review, double capsules were identified in 14 of 626 breast implants.1 We report the detection of incidental double capsules both in a patient and from our previously described porcine model.2 A 30-year-old woman with rapid development of bilateral Baker grade III capsular contractures and seroma was found to have bilateral double capsules at the time of surgery in November of 2010. Also, six custom smooth breast implants (TyRx, Inc., Monmouth Junction, N.J.) were inserted into two adult female nonlactating white pigs using sterile surgical techniques as part of a larger study. Each breast implant was inoculated with 106Staphylococcus epidermidis. The implants were removed at 20 weeks, and two were noted to have double capsules. Samples were subjected to enhanced microbiology, scanning electron microscopy, and polymerase chain reaction to detect the icaA gene, a potentiator of biofilm formation. Enhanced cultures from each breast capsule grew S. epidermidis. Polymerase chain reaction analysis of the isolated bacteria showed icaA positivity. Scanning electron microscopy analysis of both capsules detected the presence of cocci-shaped bacteria colonies encased in exopolysaccharide as biofilm on the surfaces of both capsules (Fig. 1).Fig. 1: Biofilm on the surface of the human double capsule showing cocci encased in bacterial proteins.Blinded analysis of the pig before explantation revealed Baker grade III and IV capsular contracture around these implants. Further laboratory dissection revealed the presence of double capsules in both specimens (Fig. 2). Enhanced cultures revealed the growth of S. epidermidis and polymerase chain reaction analysis showed ica gene positivity. Scanning electron microscopic analysis of both capsule specimens confirmed the presence of cocci-shaped bacterial colonies encased in exopolysaccharide as biofilm.Fig. 2: Dissection of pig breast capsule demonstrating a double capsule surrounding a breast implant left in situ.The detection of double capsule in association with bacterial biofilm is a novel and potentially important finding. The double capsules in our human samples were associated with both seroma and Baker grade III capsular contracture. The finding of a double capsule in the porcine model represents the first in a nonhuman species and was associated with both contracture and deliberate inoculation with S. epidermidis. Microscopic, molecular, and microbiological analyses have identified staphylococcal bacterial biofilm infection of the capsule from all four specimens. This is consistent with our previous findings that subclinical bacterial biofilm infection is an important factor in the pathogenesis of capsular contracture.2 Our findings suggest that chronic infection with a bacterial biofilm may also be an important etiologic factor in double capsule formation. The reported association by Hall-Findlay of double capsule with textured implants and late seroma is also interesting,1 as both these clinical parameters have been reported in patients with anaplastic large cell lymphoma following breast augmentation.3 There is strong evidence that chronic bacterial infection can cause lymphoma in both humans4 and animals.5 It could be that the finding of bacterial biofilm in these double capsule specimens may point to an important and as yet unreported causative association between chronic bacterial biofilm infection and the genesis of this rare malignancy. James M. Allan, M.B.B.S. Anita S. W. Jacombs, M.S. Honghua Hu, Ph.D. Surgical Infection Research Group Steven L. Merten, F.R.A.C.S. Unit of Cosmetic and Plastic Surgery Anand K. Deva, M.S., F.R.A.C.S. Surgical Infection Research Group and, Unit of Cosmetic and Plastic Surgery, Australian School of Advanced Medicine, Macquarie University, Sydney, Australia ACKNOWLEDGMENTS The study was supported in part by an Aesthetic Surgery Education and Research Foundation grant. The authors would like to thank Dr. Pedro Miguel Valente and A/Prof. Karen Vickery. DISCLOSURE Dr. Deva has been a consultant to Johnson & Johnson Medical. The Surgical Infection Research Group is currently engaged in contract research with Allergan, Inc.