The breast: a clean-contaminated surgical site

Capsular contracture is one of the most common complications associated with breast implants. While the cause of this process has not yet been elucidated, subclinical infection is a likely culprit.

The authors assess the hypothesis that a probable source of contamination is endogenous breast bacteria, likely originating in the ducts themselves and most concentrated near the nipple.

Twenty-five healthy patients presenting for routine reduction mammaplasty were recruited as study participants. Tissue samples were taken intraoperatively from the periareolar, inframammary, and axillary regions of each sampled breast. Specimens were then processed in the microbiology laboratory, and quantitative bacterial counts were obtained.

Of the 50 breasts sampled, 19 yielded positive culture results, for a rate of 38%. There was a significant difference in the positive culture rate among all three sites, with increasing quantitative bacterial counts in the axillary, inframammary, and periareolar regions, respectively. The most commonly-identified organisms in this study included various species of Staphylococcus and Propionibacterium acnes, with S. epidermidis being the most common.

The breast harbors significant endogenous bacteria that can become the source of spontaneous or postoperative infection. Positive intraoperative cultures with high quantitative counts suggest that breast tissue harbors more bacteria than normal skin flora. Routine perioperative antibiotic prophylaxis may be suboptimal for the prevention of foreign body seeding in this setting. Furthermore, bacterial concentrations are highest in areas with the most ductal tissue, namely the periareolar region. These findings may be helpful when considering which incision site to select for augmentation mammaplasty.