BReast Ecology Assessment in the STudy of local MicroFlora - Study Protocol.

Introduction: Recent articles have described an endogenous breast flora, particularly in the nipple ducts, with potential implications in the outcome of aesthetic breast surgery. To characterize the ecology of the breast, we designed a study to assess the microbial species identified on the breast skin and parenchyma in patients undergoing breast surgical interventions.

Methods: AFTER OBTAINING INFORMED CONSENT AND BACKGROUND DATA ON CONCURRENT DISEASES, PREVIOUS CONTACT WITH THE HOSPITAL SYSTEM AND PRIOR USE OF ANTIBIOTICS, SAMPLES ARE COLLECTED PREOPERATIVELY FROM THREE AREAS OF THE BREAST SKIN, BILATERALLY: the inframammary fold, the areola and the axilla, prior to decontamination. These samples will serve as positive controls and will aid in characterizing the normal breast skin flora. After preoperative decontamination, samples are again collected, to check for any residual bacterial flora and the nipple is sealed with Tegaderm (3M, USA) and betadine ointment, to reduce any putative bacterial load. Intraoperatively, samples are collected from: a) the incision line (dermal level): 1. superficially, 2. medium depth in the breast parenchyma, 3. deep parenchyma, and b) axillary parenchyma (where possible), together with a bioptic fragment. Postoperatively, a second nipple sample is collected. For secondary breast augmentation surgeries, capsular biopsy is also performed (where relevant), and the implants undergo sonication, to allow biofilm identification. In the laboratory, all samples are cultured on blood agar incubated with CO2, cystine lactose electrolyte deficient medium and Sabouraud gentamicin-chloramphenicol agar. For positive culture samples, the number of colonies and their morphologic characteristics are reported. Identification will be carried out with MALDI-TOF and VITEK (bioMérieux, France), yielding automated antibiotic sensitivity profiles. For all germs with sensitivity profiles differing from the wild-type strain, E-tests will be performed. Follow-up information on the postoperative evolution will be collected and analyzed for potential factors predictive of good evolution.

Discussion: This study will provide important information about the microflora of the breast skin, its sensitivity profile, and the degree of contamination of the nipple ducts and parenchyma, if any, addressing a scientific hypothesis insufficiently explored so far.