Infectious Loss of Tissue Expanders in Breast Reconstruction Are We Treating the Right Organisms? Gabriel M. Klein, MD,* Brett T. Phillips, MD, MBA,† Alexander B. Dagum, MD,* Duc T. Bui, MD,* and Sami U. Khan, MD* Background: Postoperative infections following tissue expander-based breast re- construction represent a significant threat to the reconstructive process. Studies have found the incidence to be as high as 29%. There has been abundant research into the risk factors associated with these infections, although very few studies have focused on the causative organisms. The purpose of this study was to in- vestigate the bacterial flora associated with tissue expander infections after breast reconstruction. Methods: A retrospective analysis of all patients who underwent tissue expander- based breast reconstruction at our institution between February 2010 and April 2013 was conducted. The medical records were reviewed for demographic infor- mation, medical history, operative technique, postoperative course, and culture results. Descriptive data analysis was then performed. Results: A total of 56 tissue expander infections were identified in 49 patients during the study period. 41.1% of the cultures grew gram-positive organisms, whereas 28.6% grew gram-negative species. The 2 most common organisms were Staphylococcus aureus (17.9%) and Staphylococcus epidermidis (14.3%). Pseudomonas aeruginosa was the most frequent gram-negative species and was also the third most frequent organism cultured (10.9%). Discussion: Due to the high rate of infection in breast reconstruction patients, ad- equate perioperative prophylaxis is necessary. The surgeon must also be prepared to treat patients who may return with infection postoperatively. Although the ma- jority of our infections were secondary to normal skin flora, a significant propor- tion were caused by gram-negative species. Given these results, the empiric antibiotic of choice for postoperative infections should be reconsidered to cover for these various organisms. Key Words: breast reconstruction, tissue expander, infection, implant infection (Ann Plast Surg 2017;78: 149–152) T he incidence of breast cancer in the United States has been increas- ing in recent years, and now has reached over 230,000 cases per year. 1 With the growing use of mastectomy, an increasing number of patients have pursued breast reconstruction, most recently as high as 40%. 2 Breast reconstruction has been shown to improve quality of life, aid in coping with disease, and decrease the psychiatric morbidity asso- ciated with both breast cancer and mastectomy. 3 Despite the options of autologous breast reconstruction, roughly 79% of all breast reconstruc- tions are implant-based. 4 The benefits of implant-based reconstruction are secondary to the decreased operative time, minimal recovery, and lack of donor site morbidity. 5 Implant-based reconstruction has also been shown to produce acceptable restoration of body while using a less complex approach. 6,7 Despite the popularity of implant-based breast reconstruction, there are many complications secondary to implant placement and tissue expansion. Of all the complications associated with tissue expander-based breast reconstruction, infection represents one of the most problematic, especially because it often leads to the most devastating result, loss of the expander. Surgical site infections (SSI) in other breast operations are uncommon, with an incidence of 1% to 2%. 8–10 This low number is expected, because breast surgery is considered a clean surgical case. In comparison, implant-based reconstruction has a significant risk of infection, with an incidence of infection as high as 29% in the literature. 9,11–15 These infections, which can range from simple celluli- tis to a deep space or implant infection, can significantly increase the cost of the reconstructive process and are associated with significant patient morbidity, including delay of oncologic treatment for these women. SSI alone has been shown to increase the cost of breast recon- struction by US $4091 per patient, whereas prolonging hospital stays by an average of 6.5 days. 8,16 Deep infection can subsequently lead to re- moval of the implant or expander, and has been found to be the primary cause of implant reconstructive failure. 17,18 Although surgeons will do whatever is possible to prevent prosthetic loss, fewer than 50% of im- plants can be salvaged after a deep space infection. 8,19 With a higher percentage of postreconstructive infections occurring during the expan- sion phase, we need to further investigate potential causative factors. 20 There are many risk factors associated with postoperative infec- tions including poorly perfused mastectomy skin flaps, the presence of a foreign body, and skin flap stretching from the expansion process. These issues can affect skin flap perfusion and the local immune re- sponse. Multiple studies have found that preoperative breast size, smoking, obesity, prolonged operating room time, irradiation, use of acellular dermal matrix (ADM), hypertension, age, and axillary dissec- tion are all directly correlated with increased risk of SSI and deep infec- tion postoperatively. 4,5,15,21–23 Despite the abundant data on risk factors for infections in breast reconstruction, only a handful of researchers have investigated the microbial causes of these infections. Early stud- ies demonstrated a preponderance for skin flora as the causative organisms, 9,20,24–28 which is expected given the nature of the surgery. However, in this age of overutilization of antibiotics and an ever- changing microbial landscape, reconstructive surgeons need to be aware of atypical infections and resistant microorganisms. This study was designed to investigate the current trends in postoperative infection af- ter tissue expander-based breast reconstruction. METHODS After Institutional Review Board approval, a retrospective re- view of all patients who underwent mastectomy followed by tissue expander-based breast reconstruction at our institution between February of 2010 and April 2013 was conducted. Charts were analyzed to identify which patients developed a tissue expander infection that re- quired premature tissue expander removal. Each expander was viewed as an independent data point, as the local environment may vary based on the presence of cancer, radiation, and node dissection as well as post- operative surgical site complications. The charts were also reviewed for the culture results of the periprosthetic fluid. All cultures were taken in the operating room under sterile conditions during tissue expander re- moval. The fluid within the tissue expander was not sent for culture. Received August 12, 2015, and accepted for publication, after revision, April 12, 2016. From the *Division of Plastic Surgery, Department of Surgery Stony Brook University Medical Center, Stony Brook, NY; and †Division of Plastic, Maxillofacial, and Oral Surgery, Department of Surgery Duke Medicine, Durham, NC. Conflicts of interest and sources of funding: This project received no outside funding. No authors have any conflicts of interest, financial or otherwise, related to this research. Reprints: Sami U. Khan, MD, Division of Plastic and Reconstructive Surgery, Department of Surgery, Health Sciences Center T19-069, Stony Brook Medicine, Stony Brook, NY 11794-8191. E-mail: Sami.Khan@stonybrookmedicine.edu. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0148-7043/17/7802–0149 DOI: 10.1097/SAP.0000000000000847 BREAST SURGERY Annals of Plastic Surgery • Volume 78, Number 2, February 2017 www.annalsplasticsurgery.com 149 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.