Capsular Biofilm Formation at the Interface of Textured Expanders and Human Acellular Dermal Matrix: A Comparative Scanning Electron Microscopy Study.

BACKGROUND: Despite benefits in reducing capsular contractures, textured implants have been associated with significant pitfalls, such a propensity for biofilm formation. Few studies have investigated whether the use of acellular dermal matrix on textured implants produces similar findings. This study aims to characterize biofilm formation at the capsular-acellular dermal matrix interface with scanning electron microscopy. METHODS: The authors performed a prospective observational pilot study in patients undergoing two-stage expander-to-permanent implant exchange. Patients were inflated with Biocell or Siltex expanders, and specimens from the capsular-pectoralis interface and capsular-acellular dermal matrix interface were obtained and examined under scanning electron microscopy for capsular ingrowth and biofilm formation using the Van Herdeen Biofilm Grading System and the Biofilm Thickness Grading Scale. RESULTS: Nine patients including 14 breasts (28 capsular samples in total) were examined. Thick biofilm formation was observed in all specimens from the capsular-acellular dermal matrix interface with Biocell and 25 percent of capsule-pectoralis interface, whereas no biofilm formation was found in Siltex implants. For Biocell implants, a significant difference in biofilm coverage between the upper and lower poles was observed using the Van Herdeen Biofilm Grading System (p = 0.0028) and the Biofilm Thickness Grading Scale (p = 0.0161). CONCLUSIONS: Biocell implants produce a significant rate of biofilm formation over acellular dermal matrix-covered capsules, which is not present in the muscular region or in Siltex implants. Further randomized controlled trials will further elucidate the clinical impact of using acellular dermal matrices with macrotextured implants. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Do Bacteria and Biofilm Play a Role in Double-Capsule Formation around Macrotextured Implants?

BACKGROUND: The double capsule is a complication mostly described in aggressive macrotextured implants. Mechanical shear stress applied onto an immature periprosthetic capsule has been linked to their formation. The authors aim to demonstrate the role of bacterial phenotype and biofilm in the development of the double capsule. METHODS: Seven double capsules formed at the interface of macrotextured breast expander implants were studied using scanning electron microscopy. Two samples for each surface of the inner capsule layer (the prosthesis interface and the intercapsular space) were analyzed for bacteria cell size, bacterial density, and biofilm deposition. RESULTS: Although all routine bacterial cultures were negative, the prosthesis interface had both higher bacteria load and biofilm deposition compared with the intercapsular space (Mann-Whitney U test, p = 0.004 and p = 0.008, respectively). Moreover, bacteria cell sizes were significantly smaller at the prosthesis interface in six of seven samples. Comparison of bacteria density and biofilm dispersion showed an increase of biofilm extracellular matrix deposition over 2000 cells/mm (linear regression, p = 0.0025). These results indicate a common trend among bacteria species. CONCLUSIONS: Bacterial expression between the different surfaces of the double capsule displays significant differences; bacteria at the prosthesis interface are mostly in a biofilm state, whereas they demonstrate a planktonic phenotype at the intercapsular space. When a sufficient amount of bacteria are present at a specific location, quorum sensing may trigger a biofilm phenotypic switch in planktonic bacteria cells. Biofilm formation may alter capsule formation through immune response, thereby weakening capsule strength and facilitating extracellular matrix delamination and double-capsule formation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

[Analysis of the bacteria spectrum and clinical treatment of topical skin infection during soft tissue expander implantation].

Objective: To analyze the identification and antibiotics susceptibility of infectious bacteria obtained from the topic skin infection during soft tissue expander implantation. Methods: A retrospective analysis of 121 cases with local infections during soft tissue expander implantation between 2003 to 2012 in Department of Plastic and Reconstructive Surgery, Xijing Hospital was performed. The efficacy of clinical management of local infection was evaluated. Laboratory examination on exudates bacterial pathogen and antibiotic susceptibility were performed. . Results: Based on the severity of wound infection, change of dressings, wound debridement, exudates drainage and intravenous antibiotics administration were applied. All infections were successfully controlled although the expanders were removed in 16 cases with severe infections. Total success rate of expansion in this cohort was 89.33％.Twenty-nine exudates samples collected from either skin rupture wounds or skin outlets of connector tubes of externally placed infusion ports in 29 patients underwent bacterial culture and antibiotic susceptibility test. The 23 samples showed positive while the rest 6 samples showed negative on bacterial identification in the bacterial culture test.Staphylococcus aureus strain was found in 20 samples (86.96％),Staphylococcus epidermidis in 1 sample, Klinefelter Citrobacter in 1 sample, and Aeromonas hydrophila in 1 sample. More than 80％ of the pathogens were susceptive to cefazolin, oxacillin, and levofloxacin. Conclusions: Staphylococcus aureus is the main pathogen of infection at expander implantation site. The local dressing change,surgical debridement, continuous infusion drainage, and the use intravenous antibiotics are the effective managements

Microbial growth within saline-filled tissue expanders.

BACKGROUND: Tissue expander based reconstruction is the most common restorative procedure used following mastectomy. Infection is a common complication in the post-operative period and may lead to failure of the reconstruction. Various previous studies have investigated the potential sources of infection during these procedures. The purpose of this study was to examine the fluid within the saline-filled tissue expander at time of implant exchange for the presence of microbial growth. METHODS: Twenty-five patients (39 breasts) were enrolled in the study. Fluid samples were sent for Gram stain, aerobic, anaerobic, fungal, and acid-fast bacilli (AFB) cultures. Average age was 53.1. Mean time to exchange was 7.7 months. Average follow-up was 25 months. RESULTS: None of the samples were positive for microbial growth at final culture (0/39). DISCUSSION: These results show the tissue expander fluid maintains a microbial-free environment during the expansion process, and is unlikely a significant source of contamination in cases of infection. LEVEL OF EVIDENCE: Level II, prospective cohort, therapeutic study.

Role of bacterial biofilms in patients after reconstructive and aesthetic breast implant surgery.

INTRODUCTION: Capsular contracture is a feared complication following both reconstructive and aesthetic breast surgery. The etiology is uncertain, but bacterial biofilms have been suggested as trigger for chronic peri-implant inflammation, eventually leading to capsular contracture. METHODS: Data were extracted from patient records included in a prospective cohort between 2008 and 2010. We compared patients who underwent submuscular breast reconstruction using expander implants and those needing implant removal for capsular contracture after aesthetic submuscular breast augmentation. RESULTS: Of 36 included breast implants from 27 patients, 18 implants were inserted for reconstructive reasons and 18 for aesthetic reasons. The median indwelling time was 3 years for aesthetic implants and 3 months for reconstructive expanders. Overall, sonication cultures were positive in 13 implants (36%). In aesthetic implants, sonication cultures were positive in 28% and sonication cultures were positive in expander implants in 44%. Propionibacterium acnes and coagulasenegative staphylococci were predominant. CONCLUSION: Sonication cultures were positive in approximately 33% of removed breast implants and were comparable for reconstructive expander and aesthetic implants. These findings support the hypothesis that bacterial biofilms play a role in the pathogenesis of capsular contracture, especially after expander reconstruction, as these implants are at the highest risk of contamination during repeated implant-filling procedures.

Breast tissue expander-related infections: perioperative antimicrobial regimens.

OBJECTIVE: The rate of postmastectomy tissue expander (TE) infection remains excessively high, ranging between 2% and 24%. We hypothesized that current perioperative antimicrobial regimens utilized for breast TE reconstruction may be outdated as a result of recent changes in microflora and susceptibility patterns. DESIGN AND METHODS: We reviewed the records of all patients who had a TE reconstructive procedure and developed a definite breast TE infection between 2003 and 2010 at MD Anderson Cancer Center. Antimicrobials were stratified into 3 groups: systemic perioperative, local irrigation, and oral immediate postoperative antimicrobials. These were considered discordant if they did not target the isolated organisms, while a breakthrough infection was defined as an infection that occurred despite concordant antimicrobial coverage. RESULTS: Overall, 75 patients with a definite TE infection were identified. The most common organisms identified were methicillin-resistant Staphylococcus epidermidis (29%), methicillin-resistant Staphylococcus aureus (15%), and gram-negative rods (26%). The use of systemic perioperative antimicrobials was deemed discordant in 51% of the cases. Although 79% of the patients received broad-spectrum perioperative local antimicrobial irrigation, 63% developed a breakthrough infection. Even though 61% received oral postoperative prophylactic antimicrobials, 63% of the times they were deemed discordant. CONCLUSIONS: Contrary to the proven effectiveness of a single dose of perioperative antibiotics, the common use of local antimicrobial irrigation and prolonged postoperative oral antibiotics appears to be an inadequate component of our preventive armamentarium. Also, because methicillin-resistant staphylococcal and pseudomonal infections occurred approximately 60% of the time, at institutions that have observed an increase of these organisms, it may be prudent that perioperative antimicrobials target these microorganisms.

Microbial biofilms and breast tissue expanders.

We previously developed and validated a vortexing-sonication technique for detection of biofilm bacteria on the surface of explanted prosthetic joints. Herein, we evaluated this technique for diagnosis of infected breast tissue expanders and used it to assess colonization of breast tissue expanders. From April 2008 to December 2011, we studied 328 breast tissue expanders at Mayo Clinic, Rochester, MN, USA. Of seven clinically infected breast tissue expanders, six (85.7%) had positive cultures, one of which grew Propionibacterium species. Fifty-two of 321 breast tissue expanders (16.2%, 95% CI, 12.3-20.7%) without clinical evidence of infection also had positive cultures, 45 growing Propionibacterium species and ten coagulase-negative staphylococci. While vortexing-sonication can detect clinically infected breast tissue expanders, 16 percent of breast tissue expanders appear to be asymptomatically colonized with normal skin flora, most commonly, Propionibacterium species.

Fungal colonization within a tissue expander: a case report.

Fungal contamination derived from prosthetic substances is not common, although because of the following reasons the number of cases has increased in the recent years: increased life expectancy, and therefore a greater number of surgical candidates; higher rates of underlying diseases, which are accompanied by immunosuppressive disorders that can cause a higher susceptibility for such infections. Most reports of infection in breast prosthesis and tissue expanders are bacterial infections, and fungi cases are still rare. Hereby, we report a case of Aspergillus colonization in a tissue expander of a patient with an old burn scar. This fungal growth inside saline-filled tissue expander was asymptomatic and not troublesome. It also caused no changes in the patient's treatment course.

Microbiological evaluation of tissue expanders in patients who had first stage breast reconstruction.

Capsular contracture is one of the most common complications associated to the use of foreign materials in reconstruction after mastectomy and aesthetic breast augmentation. Many risk factors, causes, and conditions seldom associated with capsular contracture have been identified but none of these have been confirmed by published data. Among these, subclinical infections (particularly those caused by Staphylococcus epidermidis) seem to be one of the most likely. In the present study we analysed the correlation between capsular contracture and the incidence of periprosthetic subclinical infection in two groups of patients who had first-stage breast reconstruction: one group of patients who were not having adjuvant or neoadjuvant radiotherapy for breast cancer (n = 25) and a second group of patients who had had quadrantectomy and radiotherapy (QUART) and successive radical mastectomy for recurrent disease (n = 25). Patients who had radiotherapy had a significantly higher incidence of subclinical infection (n = 13) than patients who did not (n = 1), but there was no statistical correlation between subclinical infection and capsular contracture. Subclinical infections seemed to present at a later stage and under certain local and systemic circumstances that favoured bacterial growth, such as radiotherapy.

Outcome following removal of infected tissue expanders in breast reconstruction: a 10-year experience.

Although several studies have analyzed risk factors for tissue expander removal prior to permanent implant placement in breast reconstruction, the outcome following explantation because of infection is unknown. From a prospectively maintained database covering a 10-year period, 39 such patients were identified. Twelve (30.8%) had prior radiotherapy. Nine patients (23%) underwent reexpansion, 3 (7.7%) had a latissimus dorsi flap and expander, and 1 (2.6%) received a free transverse rectus abdominis flap. Recurrent infection occurred in 1 reexpanded patient. Two patients developed late contractures. All other reconstructions were successful. Twenty-six patients (66.7%) did not undergo secondary reconstruction, most commonly due to a combination of patient preference, cancer progression, and radiotherapy. After removal of an infected expander, most patients who are interested and remain good candidates can still be reconstructed. Reexpansion was successful in patients without prior radiotherapy. Secondary reconstruction with autologous tissue is appropriate when there is a history of radiotherapy.

Retrospective case review of capsular contracture after two-stage breast reconstruction: is colonization of the tissue expander pocket associated with subsequent implant capsular contracture?

Periprosthetic capsular contracture is a common problem associated with implant-based breast reconstruction. The purpose of this study was to determine if bacterial colonization of the tissue expander contributes to contracture of the permanent implant. Medical records were reviewed for 86 patients (124 tissue expanders) between 1997 and 2001 in 1 institution. Three specimens taken from the expander were cultured. The overall incidence of colonization was 42.7%; 49.4% (38.8-60.0) of immediate and 28.2% (14.1-42.3) of delayed expanders had at least 1 positive culture site (P = 0.043). The most common organisms were Propionibacterium acnes (57.6%), Staphylococcus epidermidis (31.0%), and Peptostreptococcus (5.8%). Statistical analysis revealed no significant difference between colonization of the expander and capsular contracture of the permanent prosthesis (P = 0.59). 45.8% (25.9-65.8) of breasts irradiated preoperatively developed contracture versus 14% (7.2-20.8) with no irradiation (P = 0.0013). These results suggest that colonization of the expander occurs frequently, irradiation predisposes to contracture, and colonization did not contribute to secondary implant contracture in this study population.

Activity of antimicrobial-impregnated silicone tissue expanders.

Because bacterial colonization of medical devices may result in clinical infection, it is conceivable that antimicrobial impregnation of tissue expanders may reduce the rate of infection. The objective of this in vitro study was to examine the spectrum, durability, and shelf-life antimicrobial activity of minocycline/rifampin-impregnated silicone tissue expander shells. The impregnated devices exhibited zones of inhibition at baseline against Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli. The impregnated devices exhibited strong residual activity against S. epidermidis and S. aureus after suspension in serum at 37 degrees C for 4 weeks. There was no significant decrease in the size of zones of inhibition after storing the impregnated devices at room temperature for 1 year. These results indicate that minocycline/rifampin-impregnated tissue expander shells provide broad-spectrum and durable antimicrobial activity and that the shelf-life antimicrobial activity exceeds 1 year. These findings prompt future exploration of the anti-infective efficacy of these antimicrobial-impregnated devices.

Microbial growth in saline breast implants and saline tissue expanders.

The subject of microbial growth within the saline medium of prosthetic breast implants has been one of great controversy in recent years. Although several articles have described microbial growth within the tissue surrounding implanted breast prostheses, few have attempted to determine the possibility of such contamination of the luminal saline. The authors studied the intraluminal saline medium of a series of explanted breast prostheses with the objective of identifying any microbial contamination. Over a 6-month period, a consecutive series of saline-filled breast implants and tissue expanders were removed from 37 patients. Under the supervision of a microbiologist, saline extracted from each implant was subjected to bacterial and fungal cultures, Gram staining, and acid-fast staining. A total of 24 saline-filled breast implants were removed from 15 patients, and 32 saline-filled tissue expanders were removed from 22 patients. The average length of implantation was 28.1 months for the implants and 7.1 months for the expanders. None of the saline within the implants or expanders within our series displayed any evidence of microbial contamination. These results suggest that microbial contamination of the luminal saline of prosthetic breast implants is an extremely unlikely event.