Microbial biofilms and breast tissue expanders

Clinical Evaluation of Microbial Communities and Associated Biofilms with Breast Augmentation Failure

The incidence of breast implant illness (BII) and BII-related explant procedures has not decreased with current surgical and treatment techniques. It is speculated the main underlying cause of BII complications is the result of chronic, sub-clinical infections residing on and around the implant. The infection, and subsequent biofilm, produce antagonistic compounds that drive chronic inflammation and immune responses. In this study, the microbial communities in over 600 consecutive samples of infected explant capsules and tissues were identified via next-generation sequencing to identify any commonality between samples. The majority of the bacteria identified were Gram-positive, with Cutibacterium acnes and Staphylococcus epidermidis being the dominant organisms. No correlation between sample richness and implant filling was found. However, there was a significant correlation between sample richness and patient age. Due to the complex nature, breast augmentation failures may be better addressed from a holistic approach than one of limited scope.

The Effect of Early Cultures and Dual-port Expanders on Two-stage, Prepectoral Breast Reconstruction: The 25/25 Study

Background

Two-stage tissue expander to implant surgery remains the predominant technique for breast reconstruction. Unfortunately, there is a high incidence of reconstruction failure which portends a financial and emotional burden. Most failures are related to postmastectomy skin flap necrosis and infection. Recently, a dual-port tissue expander was introduced to the market, and the authors hypothesize that early cultures from the peri-implant fluid will guide antibiotic treatment and decrease reconstruction failure.

Methods

This is a cohort study of 50 consecutive patients treated for breast cancer or genetic susceptibility via a two-stage, prepectoral technique. The first 25 patients (46 breasts) were treated with a variety of tissue expanders, and the subsequent 25 patients (47 breasts) received a dual-port expander. Routine cultures from the drain port were taken from the dual-port group at the second postoperative visit, and cultures were taken in the control group only when signs of infection were present. All other procedures and interventions were similar.

Results

Fifty patients, totaling 93 breasts, completed the study with a mean follow-up of 145 days. There were no statistically significant demographic or pathologic differences between groups. Fifteen tissue expanders were explanted in the control group and five in the dual-port cohort (32.6% versus 10.6%, P = 0.012). All bacteria in the control group failures were either methicillin-resistant Staphylococcus aureus or Staphylococcus epidermidis, whereas failures in the dual-port group varied.

Conclusion

Treatment of routine, early cultures from a dual-port expander led to a statistically significant decrease in tissue expander explantation.

Intraoperative Assessment of Endogenous Microbiota in the Breast

OBJECTIVE

 Breast surgery is considered a clean surgery; however, the rates of infection range between 3 and 15%. The objective of the present study was to intraoperatively investigate the presence of autochthonous microbiota in the breast.

METHODS

 Pieces of breast tissue collected from 49 patients who underwent elective breast surgery (reconstructive, diagnostic, or oncologic) were cultured. The pieces of breast tissue were approximately 1 cm in diameter and were removed from the retroareolar area, medial quadrant, and lateral quadrant. Each piece of tissue was incubated in brain heart infusion (BHI) broth for 7 days at 37°C, and in cases in which the medium became turbid due to microorganism growth, the samples were placed in Petri dishes for culturing and isolating strains and for identifying species using an automated counter.

RESULTS

 Microorganism growth was observed in the samples of 10 of the 49 patients (20.4%) and in 11 of the 218 pieces of tissue (5%). The detected species were Staphylococcus lugdunensis, Staphylococcus hominis, Staphylococcus epidermidis, Sphingomonas paucimobilis, and Aeromonas salmonicida. No patient with positive samples had clinical infection postoperatively.

CONCLUSION

 The presence of these bacteria in breast tissue in approximately 20% of the patients in this series suggests that breast surgery should be considered a potential source of contamination that may have implications for adverse reactions to breast implants and should be studied in the near future for their oncological implications in breast implant-associated large-cell lymphoma etiology.

Challenges in the Microbiological Diagnosis of Implant-Associated Infections: A Summary of the Current Knowledge

Implant-associated infections are characterized by microbial biofilm formation on implant surface, which renders the microbiological diagnosis challenging and requires, in the majority of cases, a complete device removal along with a prolonged antimicrobial therapy. Traditional cultures have shown unsatisfactory sensitivity and a significant advance in the field has been represented by both the application of the sonication technique for the detachment of live bacteria from biofilm and the implementation of metabolic and molecular assays. However, despite the recent progresses in the microbiological diagnosis have considerably reduced the rate of culture-negative infections, still their reported incidence is not negligible. Overall, several culture- and non-culture based methods have been developed for diagnosis optimization, which mostly relies on pre-operative and intra-operative (i.e., removed implants and surrounding tissues) samples. This review outlines the principal culture- and non-culture based methods for the diagnosis of the causative agents of implant-associated infections and gives an overview on their application in the clinical practice. Furthermore, advantages and disadvantages of each method are described.

Comparison of the Incidence of Capsular Formation in Two-Stage, Implant-Based Breast Reconstruction Using an Insertion Funnel and Sizer

Purpose

Capsular formation around breast implants can produce various complications, including erythema, tenderness, discomfort, and breast deformation. Moreover, the capsule is thought to be correlated with breast implant-associated anaplastic large cell lymphoma. The proposed technique of capsule reduction can prevent some of these complications. Thus, the authors suggest a no-touch technique in two-stage, implant-based breast reconstruction. Patients and Methods. This single-center retrospective study evaluated the medical records and digitalized pathological slides of patients who underwent two-stage, implant-based breast reconstruction between February 2018 and May 2019. The selected patients were divided into group A and group B. Group A underwent a no-touch technique that included the following two steps: (1) using a sizer as the frame to create the submuscular and acellular dermal matrix (ADM) pocket for expander insertion and (2) inserting the expander through the funnel. After the second stage of implant insertion, the capsule was harvested for biopsy of the ADM, chest wall, and muscle.

Results

This study included 33 breasts (31 patients): 18 in group A and 15 in group B. The capsular thicknesses of the ADM, the chest wall, and the muscle of group A were significantly thinner than those in group B. Pearson's correlation coefficient indicated negative correlations between capsular thickness and age; underlying disease; lesion side; interval of two-stage implant insertion; size of the expander; and radiotherapy, chemotherapy, or hormone therapy.

Conclusion

To reduce the incidence of capsular formation following breast reconstruction using prostheses, a no-touch technique that uses a funnel and sizer to avoid implant contact is both efficient and beneficial.

A Janus-Faced Bacterium: Host-Beneficial and -Detrimental Roles of Cutibacterium acnes

The bacterial species Cutibacterium acnes (formerly known as Propionibacterium acnes) is tightly associated with humans. It is the dominant bacterium in sebaceous regions of the human skin, where it preferentially colonizes the pilosebaceous unit. Multiple strains of C. acnes that belong to phylogenetically distinct types can co-exist. In this review we summarize and discuss the current knowledge of C. acnes regarding bacterial properties and traits that allow host colonization and play major roles in host-bacterium interactions and also regarding the host responses that C. acnes can trigger. These responses can have beneficial or detrimental consequences for the host. In the first part of the review, we highlight and critically review disease associations of C. acnes, in particular acne vulgaris, implant-associated infections and native infections. Here, we also analyse the current evidence for a direct or indirect role of a C. acnes-related dysbiosis in disease development or progression, i.e., reduced C. acnes strain diversity and/or the predominance of a certain phylotype. In the second part of the review, we highlight historical and recent findings demonstrating beneficial aspects of colonization by C. acnes such as colonization resistance, immune system interactions, and oxidant protection, and discuss the molecular mechanisms behind these effects. This new insight led to efforts in skin microbiota manipulation, such as the use of C. acnes strains as probiotic options to treat skin disorders.

Minimally invasive salvage of infected breast tissue expanders: A continuous closed irrigation technique based on surface biofilm disruption

BACKGROUND

Removal of the infected device has been the general treatment for device-associated infection in antibiotic failure. There have been anecdotal attempts to salvage infected medical devices by introducing a continuous closed irrigation system.

OBJECTIVE

This study examines whether continuous closed irrigation of an infected device is a successful alternative to removal in patients with recalcitrant device-associated infection.

METHODS

Patients who were diagnosed with recalcitrant periexpander infections during the course of expander-implant breast reconstruction from 2010 to 2018 were enrolled in a retrospective case-control study. Patients who failed antibiotics before 2017 underwent expander removal, but patients since 2017 underwent continuous closed irrigation of the infected expanders. Treatment details and clinical outcomes were compared. Rationale for expander irrigation was based on review of the current literature on biofilm research.

RESULTS

During the study period, 21 out of the 1176 patients were diagnosed with periexpander infection recalcitrant to antibiotic therapy. Among the 21 patients, 16 underwent expander removal and five underwent expander irrigation. Clinical outcomes were comparable in terms of resolution of infection signs. The irrigation group showed fewer patients who abandoned reconstruction after infection treatment (removal = 11/16, irrigation = 1/5). Literature review revealed that expander irrigation might have induced hydrodynamic disruption of the biofilm structure.

CONCLUSION

Expander irrigation was less invasive than removal and effective in suppressing severe recalcitrant periexpander infection. Continuous closed irrigation of infected expander devices may be a successful antibiofilm strategy in treating device-associated infections in select patients.

Back to Basics: Could the Preoperative Skin Antiseptic Agent Help Prevent Biofilm-Related Capsular Contracture?

BACKGROUND

Capsular contracture (CC) has remained an unresolved issue throughout history. Strong evidence focuses on bacterial biofilm as its main source. A literature review revealed that more than 90% of bacteria found in capsules and implants removed from patients with Baker grade III-IV CC belong to the resident skin microbiome (Staphylococcus epidermidis, predominant microorganism). The use of an adequate preoperative skin antiseptic may be a critical step to minimize implant contamination and help prevent biofilm-related CC.

OBJECTIVES

The authors sought to compare the effect of 2 different antiseptic skin preparations: povidone-iodine (PVP-I) vs chlorhexidine gluconate (CHG) on CC proportions after primary breast augmentation through a periareolar approach.

METHODS

In June of 2014, The Society for Healthcare Epidemiology of America proposed to use CHG for preoperative skin preparation in the absence of alcohol-containing antiseptic agents as strategy to prevent surgical site infection. The clinical safety committee of a surgical center in Colombia decided to change PVP-I to CHG for surgical site preparation thereafter. The medical records of 63 patients who underwent to primary breast augmentation through a periareolar approach during 2014 were reviewed. In the first 6 months PVP-I was used in 32 patients, and later CHG was employed in 31 patients.

RESULTS

Pearson's chi-squared test to compare CC proportions between subgroups showed a statistically significant difference. The CC proportion was higher for patients who had antisepsis with PVP-I. CC was absent when CHG was employed.

CONCLUSIONS

CHG as preoperative skin antiseptic for primary breast augmentation surgery was more effective than PVP-I to help prevent biofilm-related CC.

LEVEL OF EVIDENCE: 3

Candida albicans enhances initial biofilm growth of Cutibacterium acnes under aerobic conditions

Candida albicans and Cutibacterium acnes are opportunistic pathogens that co-colonize the human body. They are involved in biofilm-related infections of implanted medical devices. The objective of this study was to evaluate the ability of these species to interact and form polymicrobial biofilms. SEM imaging and adhesion assays showed that C. acnes adhesion to C. albicans did not have a preference for a specific morphological state of C. albicans; bacteria adhered to both hyphal and yeast forms of C. albicans. C. albicans did not influence growth of C. acnes under anaerobic growth conditions, however under aerobic growth condition, C. albicans enhanced early C. acnes biofilm formation. This favorable impact of C. albicans was not mediated by secreted compounds accumulating in the medium, but required the presence of metabolically active C. albicans. The ability of these microorganisms to interact together could modulate the physiopathology of infections.

Plasma, serum, albumin, and divalent metal ions inhibit the adhesion and the biofilm formation of Cutibacterium (Propionibacterium) acnes

Adhesion and biofilm formation of human skin bacteria C. acnes on plasma, serum and albumin-coated polystyrene or in the presence of these blood components were studied. The proteins which were pre-adsorbed to polystyrene surface or added to the medium simultaneously with bacterial cells reduced C. acnes adhesion and biofilm formation by 2-5 times to compare to the control. The role of calcium, magnesium and zinc on C. acnes attachment was also assessed. Calcium (1 and 10 mM) had the inhibitory effect on C. acnes adhesion, whereas zinc (1 and 10 mM) diminished the biofilm formation of C. acnes. We also observed that C. acnes cells did not bind to erythrocytes. Thus, we suggest that bacteria C. acnes preferably colonize the plasma-poor environment due to the inhibitory effect of blood components, in particular, albumin, calcium, and zinc.

Impact of polymicrobial biofilms in catheter-associated urinary tract infections

Recent reports have demonstrated that most biofilms involved in catheter-associated urinary tract infections are polymicrobial communities, with pathogenic microorganisms (e.g. Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and uncommon microorganisms (e.g. Delftia tsuruhatensis, Achromobacter xylosoxidans) frequently co-inhabiting the same urinary catheter. However, little is known about the interactions that occur between different microorganisms and how they impact biofilm formation and infection outcome. This lack of knowledge affects CAUTIs management as uncommon bacteria action can, for instance, influence the rate at which pathogens adhere and grow, as well as affect the overall biofilm resistance to antibiotics. Another relevant aspect is the understanding of factors that drive a single pathogenic bacterium to become prevalent in a polymicrobial community and subsequently cause infection. In this review, a general overview about the IMDs-associated biofilm infections is provided, with an emphasis on the pathophysiology and the microbiome composition of CAUTIs. Based on the available literature, it is clear that more research about the microbiome interaction, mechanisms of biofilm formation and of antimicrobial tolerance of the polymicrobial consortium are required to better understand and treat these infections.

Propionibacterium acnes biofilm - A sanctuary for Staphylococcus aureus?

The purpose of this study was to measure the effect of combined culture of Propionibacterium acnes and Staphylococcus aureus on biofilm formation under different oxygen concentrations. We measured planktonic growth and biofilm formation of P. acnes and S. aureus alone and together under aerobic and anaerobic conditions. Both P. acnes and S. aureus grew under anaerobic conditions. When grown under anaerobic conditions, P. acnes with or without S. aureus formed a denser biomass biofilm than did S. aureus alone. Viable S. aureus was recovered from a16-day old combined P. acnes and S. aureus biofilm, but not a monomicrobial S. aureus biofilm.

Histologic, Molecular, and Clinical Evaluation of Explanted Breast Prostheses, Capsules, and Acellular Dermal Matrices for Bacteria

BACKGROUND

Subclinical infections, manifest as biofilms, are considered an important cause of capsular contracture. Acellular dermal matrices (ADMs) are frequently used in revision surgery to prevent recurrent capsular contractures.

OBJECTIVE

We sought to identify an association between capsular contracture and biofilm formation on breast prostheses, capsules, and ADMs in a tissue expander/implant (TE/I) exchange clinical paradigm.

METHODS

Biopsies of the prosthesis, capsule, and ADM from patients (N = 26) undergoing TE/I exchange for permanent breast implant were evaluated for subclinical infection. Capsular contracture was quantified with Baker Grade and intramammary pressure. Biofilm formation was evaluated with specialized cultures, rtPCR, bacterial taxonomy, live:dead staining, and scanning electron microscopy (SEM). Collagen distribution, capsular histology, and ADM remodeling were quantified following fluorescent and light microscopy.

RESULTS

Prosthetic devices were implanted from 91 to 1115 days. Intramammary pressure increased with Baker Grade. Of 26 patients evaluated, one patient had a positive culture and one patient demonstrated convincing evidence of biofilm morphology on SEM. Following PCR amplification 5 samples randomly selected for 16S rRNA gene sequencing demonstrated an abundance of suborder Micrococcineae, consistent with contamination.

CONCLUSIONS

Our data suggest that bacterial biofilms likely contribute to a proportion, but not all diagnosed capsular contractures. Biofilm formation does not appear to differ significantly between ADMs or capsules. While capsular contracture remains an incompletely understood but common problem in breast implant surgery, advances in imaging, diagnostic, and molecular techniques can now provide more sophisticated insights into the pathophysiology of capsular contracture.

LEVEL OF EVIDENCE

4 Therapeutic.

Bacterial colonization of VEPTR implants under repeated expansions in children with severe early onset spinal deformities

PURPOSE

Historically, severe spinal and thoracic deformities in children were treated with early long spinal fusions. This prevented further growth of the spine and thorax and often led to small stiff thoraces. Therefore, growth-retaining implants, like vertical expandable titanium ribs (VEPTR), were developed to stimulate thoracic and spinal growth. To accommodate growth, these implants have to be expanded every 6 months. Infection rates of up to 2 % per procedure are reported. Exchange of implant parts allows analyzing the development of implant-related infections and subclinical colonizations.

METHODS

In this prospective study, all patients undergoing repeat VEPTR expansion procedures at our institution were included. Preoperatively, clinical signs of infection were documented, and blood samples were taken. The removed implants were treated by sonication and microbiologically analyzed. The clinical follow-up was documented.

RESULTS

From January 2009 to May 2012, 39 children with 163 re-operations were included. Four of the 39 patients (10 %) developed clinical apparent infections and had implant removal. These were excluded and analyzed separately. Of 144 procedures, implant parts were eligible for analysis. Implant colonization was detected by sonication in 24 of 144 (16 %) operations in 18 out of 39 (46 %) patients. Repeated detection occurred in 5 (14 %) patients. No risk factors for colonization could be identified.

CONCLUSION

The rate of implant colonization is 4.5 times higher than the rate of manifest infections in VEPTR patients. Colonization may lead to a manifest infection over time. The knowledge of persistent implant colonization may change the treatment algorithm in patients with growth-retaining implants.

Role of Sonication in the Microbiological Diagnosis of Implant-Associated Infections: Beyond the Orthopedic Prosthesis

Implant-associated infections are difficult-to-treat conditions associated with high morbidity, mortality and length of hospitalization. They are characterized by biofilm formation on implant surface, which makes the microbiological diagnosis difficult and requires a complete device removal for the correct management. The sonication method, which is based on the application of long-wave ultrasounds radiating in a liquid medium, has been recently validated for the diagnosis of prosthetic joint infections. Additionally, this technique has been considered a potential tool in order to improve the microbiological diagnosis of infections associated with other foreign bodies, such as breast, urinary, endovascular and cerebral implants. In the present study, the application of sonication in the setting of implant-associated infections other than orthopedics will be reviewed.