Efficacy of Povidone Iodine Against Microbial Biofilms in Breast Implants With Different Textures: Results From an in vitro Study

Antimicrobial Efficacy of Five Wound Irrigation Solutions in the Periprosthetic Joint Infection Microenvironment In Vitro and Ex Vivo

Background/Objectives: Periprosthetic joint infections (PJI) are difficult to treat due to biofilm formation on implant surfaces and the surrounding tissue, often requiring removal or exchange of prostheses along with long-lasting antibiotic treatment. Antiseptic irrigation during revision surgery might decrease bacterial biofilm load and thereby improve treatment success. This in vitro study investigated and compared the effect of five advanced wound irrigation solutions to reduce bacterial burden in the PJI microenvironment. Methods: We treated in vitro biofilms grown on titanium alloy implant discs with clinical bacterial strains isolated from patients with PJIs, as well as abscess communities in a plasma-supplemented collagen matrix. The biofilms were exposed for 1 min to the following wound irrigation solutions: Preventia®, Prontosan®, Granudacyn®, ActiMaris® forte ('Actimaris'), and Octenilin®. We measured the bacterial reduction of these irrigation solutions compared to Ringer-Lactate and to the strong bactericidal but not approved Betaseptic solution. Additionally, ex vivo free-floating bacteria isolated directly from clinical sonication fluids were treated in the same way, and regrowth or lack of regrowth was recorded as the outcome. Results: Irrigation solutions demonstrated variable efficacy. The mean CFU log10 reduction was as follows: Octenilin, 3.07, Preventia, 1.17, Actimaris, 1.11, Prontosan, 1.03, and Granudacyn, 0.61. For SACs, the reduction was: Actimaris, 8.27, Octenilin, 0.58, Prontosan, 0.56, Preventia, 0.35, and Granudacyn, 0.24. Conclusions: All solutions achieved complete bacterial eradication in all tested ex vivo sonication fluids, except Granudacyn, which was ineffective in 33% of the samples (2 out of 6). Advanced wound irrigation solutions have the potential to reduce bacterial burden in the PJI microenvironment during revision surgery. However, their efficacy varies depending on bacterial species, growth state, and the composition of the irrigation solution. This underscores the importance of considering these factors when developing future PJI-specific irrigation solutions.

Does a Specific Sequential Combination of Antiseptic Solutions for Chemical Debridement in Periprosthetic Joint Infection Improve Outcomes vs. Solution Alone? An In Vivo Study

Background: Chemical debridement is a fundamental step during the surgical treatment of both acute and chronic periprosthetic joint infection (PJI). However, there is no consensus on the optimal solution, nor is there sufficient evidence on the optimal irrigation time and combination of solutions. In an in vitro study, our group recently demonstrated that sequential combination debridement (SCD) with 3% acetic acid (AA) followed by 10% povidone iodine (PI) and 5 mM hydrogen peroxide (H2O2) was the best strategy for reducing bacterial load. The present study aimed to validate these findings in an in vivo model. Results: The median (IQR) log CFU/mL was lower in the group of mice treated with SCD (2.85 [0.00-3.72]) than in the Bactisure™ group (4.02 [3.41-4.72], p = 0.02). While this reduction was also greater than in the PI group (3.99 [1.11-4.33]), the difference did not reach statistical significance (p = 0.19). Cell viability assays showed no differences between treatments. S. aureus bacteremia was detected in 10% of mice treated with SCD, compared to 30% in the PI group and 10% in the Bactisure™ group. The difference was not statistically significant (p = 0.36). Conclusion: Our findings confirm that SCD significantly reduced bacterial load in an in vivo S. aureus PJI model, showing superior anti-biofilm activity compared to Bactisure™ and comparable performance to PI alone. These results highlight SCD's potential to serve as a standardized chemical debridement protocol, combining enhanced efficacy with clinical applicability. Methods: We tested SCD with 3% AA for 3 min, 10% PI for 3 min, and H2O2 for 3 min in a 7-day Staphylococcus aureus (ATCC29213)-based murine femur PJI model and compared the results with single treatments of 10% PI for 3 min or Bactisure™ solution for 3 min. A sterile steel implant with local administration of saline solution for 3 min was used as a non-infected control. After completing irrigation procedures, under anesthesia, mice were euthanized, and implants were analyzed for CFU/mL counts and cell viability rates. Blood cultures were obtained pre-euthanasia to detect bacteremia.

In vitro models for studying implant-associated biofilms - A review from the perspective of bioengineering 3D microenvironments

Biofilm research has grown exponentially over the last decades, arguably due to their contribution to hospital acquired infections when they form on foreign body surfaces such as catheters and implants. Yet, translation of the knowledge acquired in the laboratory to the clinic has been slow and/or often it is not attempted by research teams to walk the talk of what is defined as 'bench to bedside'. We therefore reviewed the biofilm literature to better understand this gap. Our search revealed substantial development with respect to adapting surfaces and media used in models to mimic the clinical settings, however many of the in vitro models were too simplistic, often discounting the composition and properties of the host microenvironment and overlooking the biofilm-implant-host interactions. Failure to capture the physiological growth conditions of biofilms in vivo results in major differences between lab-grown- and clinically-relevant biofilms, particularly with respect to phenotypic profiles, virulence, and antimicrobial resistance, and they essentially impede bench-to-bedside translatability. In this review, we describe the complexity of the biological processes at the biofilm-implant-host interfaces, discuss the prerequisite for the development and characterization of biofilm models that better mimic the clinical scenario, and propose an interdisciplinary outlook of how to bioengineer biofilms in vitro by converging tissue engineering concepts and tools.

Surface Topography, Microbial Adhesion, and Immune Responses in Silicone Mammary Implant-Associated Capsular Fibrosis

Breast cancer is the most common cancer in women globally, often necessitating mastectomy and subsequent breast reconstruction. Silicone mammary implants (SMIs) play a pivotal role in breast reconstruction, yet their interaction with the host immune system and microbiome remains poorly understood. This study investigates the impact of SMI surface topography on host antimicrobial responses, wound proteome dynamics, and microbial colonization. Biological samples were collected from ten human patients undergoing breast reconstruction with SMIs. Mass spectrometry profiles were analyzed for acute and chronic wound proteomes, revealing a nuanced interplay between topography and antimicrobial response proteins. 16S rRNA sequencing assessed microbiome dynamics, unveiling topography-specific variations in microbial composition. Surface topography alterations influenced wound proteome composition. Microbiome analysis revealed heightened diversity around rougher SMIs, emphasizing topography-dependent microbial invasion. In vitro experiments confirmed staphylococcal adhesion, growth, and biofilm formation on SMI surfaces, with increased texture correlating positively with bacterial colonization. This comprehensive investigation highlights the intricate interplay between SMI topography, wound proteome dynamics, and microbial transmission. The findings contribute to understanding host-microbe interactions on SMI surfaces, essential for optimizing clinical applications and minimizing complications in breast reconstruction.

Gram-Positive Bacteria Increase Breast Implant-Related Complications: Prospective Analysis of 100 Revised Implants

BACKGROUND

Breast implant-related complications can be reduced by strict antiseptic precautions during insertion, but bacteria can often be found on implant surfaces on the occasion of revision surgery. The authors prospectively analyzed the association of bacteria found on breast implant surfaces with implant-related complications in breast implant revision cases.

METHODS

The authors analyzed a total of 100 breast implant revisions in 66 patients between August of 2018 and January of 2021. Capsular swabs and capsular samples were taken intraoperatively. Analyses on the occurrence of bacteria and the occurrence of implant-related complications were performed. In addition, correlations between bacteria-contaminated breast implant surfaces and implant-related complications were performed.

RESULTS

Implant-related complications (perforation, rupture, capsular contraction) were observed in 42 implant sites: eight unilateral and 34 bilateral cases. In total, 16 swabs showed positive bacterial growth, 10 of which were associated with a breast implant-related complication (χ 2 = x, y, and z; P = 0.006). The most common implant-based complication at contaminated prosthetics was implant rupture. The association of contaminated breast implants and implant rupture was statistically significant.

CONCLUSIONS

The authors identified a correlation between implant complications and Gram-positive bacteria found on breast implant surfaces. The most common implant-based complication seen at simultaneously positive samples was implant rupture in 50% of the authors' cases. No capsular contraction or other complications were seen.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Management of Biofilm with Breast Implant Surgery

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand how bacteria negatively impact aesthetic and reconstructive breast implants. 2. Understand how bacteria infect breast implants. 3. Understand the evidence associated with common implant infection-prevention strategies, and their limitations. 4. Understand why implementation of bacteria-mitigation strategies such as antibiotic administration or "no-touch" techniques may not indefinitely prevent breast implant infection.

SUMMARY

Bacterial infection of aesthetic and reconstructive breast implants is a common and expensive problem. Subacute infections or chronic capsular contractures leading to device explantation are the most commonly documented sequelae. Although bench and translational research underscores the complexities of implant-associated infection, high-quality studies with adequate power, control groups, and duration of follow-up are lacking. Common strategies to minimize infections use antibiotics-administered systemically, in the breast implant pocket, or by directly bathing the implant before insertion-to limit bacterial contamination. Limiting contact between the implant and skin or breast parenchyma represents an additional common strategy. The clinical prevention of breast implant infection is challenged by the clean-contaminated nature of breast parenchyma, and the variable behavior of not only specific bacterial species but also their strains. These factors impact bacterial virulence and antibiotic resistance.

An In Vitro Study to Assess the Best Strategy for the Chemical Debridement of Periprosthetic Joint Infection

Irrigation and debridement using an irrigation solution is a fundamental step during the surgical treatment of both acute and chronic periprosthetic joint infection (PJI). However, there is no consensus on the optimal solution, nor is there sufficient evidence on the optimal irrigation time and combination of solutions. Therefore, it is necessary to determine which solution or combination of solutions is most efficacious against biofilm, as well as the optimal irrigation time. We conducted an experimental in vitro model by inoculating stainless steel discs with ATCC strains of methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus, Pseudomonas aeruginosa, and a clinical strain of Staphylococcus epidermidis. The discs were all irrigated with commonly used antiseptic solutions (10% and 3% povidone iodine, hydrogen peroxide, 3% acetic acid, and Bactisure™) for 1 min, 3 min, and 5 min and their combinations for 9 min (3 min each) vs. sterile saline as a positive control. We evaluated the reduction in biofilm based on colony-forming unit (cfu) counts and in combination assays, also based on cell viability and scanning electron microscopy. All antiseptics alone reduced more than 90% of cfu counts after 1 min of irrigation; the worst results were for hydrogen peroxide and 3% acetic acid. When solutions were sequentially combined, the best results were observed for all those starting with acetic acid, in terms of both reduction of log cfu/mL counts and viable cells. We consider that a combination of antiseptic solutions, particularly that comprising the sequence acetic acid + povidone iodine + hydrogen peroxide, would be the best option for chemical debridement during PJI surgery.

A prospective randomized clinical trial to assess antibiotic pocket irrigation on tissue expander breast reconstruction

Bacterial infection is the most common complication following staged post-mastectomy breast reconstruction initiated with a tissue expander (TE). To limit bacterial infection, antibiotic irrigation of the surgical site is commonly performed despite little high-quality data to support this practice. We performed a prospective randomized control trial to compare the impact of saline irrigation alone to a triple antibiotic irrigation regimen (1 g cefazolin, 80 mg gentamicin, and 50,000 units of bacitracin in 500 mL of saline) for breast implant surgery. The microbiome in breasts with cancer (n = 16) was compared to those without (n = 16), as all patients (n = 16) had unilateral cancers but bilateral mastectomies (n = 32). Biologic and prosthetic specimens procured both at the time of mastectomy and during TE removal months later were analyzed for longitudinal comparison. Outcomes included clinical infection, bacterial abundance, and relative microbiome composition. No patient in either group suffered a reconstructive failure or developed an infection. Triple antibiotic irrigation administered at the time of immediate TE reconstruction did not reduce bacterial abundance or impact microbial diversity relative to saline irrigation at the time of planned exchange. Implanted prosthetic material adopted the microbial composition of the surrounding host tissue. In cancer-naïve breasts, relative to saline, antibiotic irrigation increased bacterial abundance on periprosthetic capsules (P = 0.03) and acellular dermal matrices (P = 0.04) and altered the microbiota on both. These data show that, relative to saline only, the use of triple antibiotic irrigation in TE breast reconstruction does impact the bacterial abundance and diversity of certain biomaterials from cancer-naïve breasts. IMPORTANCE The lifetime risk of breast cancer is ~13% in women and is treated with a mastectomy in ~50% of cases. The majority are reconstructed, usually starting with a tissue expander to help restore the volume for a subsequent permanent breast implant or the women's own tissues. The biopsychosocial benefits of breast reconstruction, though, can be tempered by a high complication rate of at least 7% but over 30% in some women. Bacterial infection is the most common complication, and can lead to treatment delays, patient physical and emotional distress and escalating health care cost. To limit this risk, plastic surgeons have tried a variety of strategies to limit bacterial infection including irrigating the pocket created after removing the breast implant with antibiotic solutions, but good-quality data are scarce. Herein, we study the value of antibiotics in pocket irrigation using a robust randomized clinical trial design and molecular microbiology approaches.

Microbial Biofilms: Applications, Clinical Consequences, and Alternative Therapies

Biofilms are complex communities of microorganisms that grow on surfaces and are embedded in a matrix of extracellular polymeric substances. These are prevalent in various natural and man-made environments, ranging from industrial settings to medical devices, where they can have both positive and negative impacts. This review explores the diverse applications of microbial biofilms, their clinical consequences, and alternative therapies targeting these resilient structures. We have discussed beneficial applications of microbial biofilms, including their role in wastewater treatment, bioremediation, food industries, agriculture, and biotechnology. Additionally, we have highlighted the mechanisms of biofilm formation and clinical consequences of biofilms in the context of human health. We have also focused on the association of biofilms with antibiotic resistance, chronic infections, and medical device-related infections. To overcome these challenges, alternative therapeutic strategies are explored. The review examines the potential of various antimicrobial agents, such as antimicrobial peptides, quorum-sensing inhibitors, phytoextracts, and nanoparticles, in targeting biofilms. Furthermore, we highlight the future directions for research in this area and the potential of phytotherapy for the prevention and treatment of biofilm-related infections in clinical settings.

The Current Knowledge on the Pathogenesis of Tissue and Medical Device-Related Biofilm Infections

Biofilm is the trigger for the majority of infections caused by the ability of microorganisms to adhere to tissues and medical devices. Microbial cells embedded in the biofilm matrix are highly tolerant to antimicrobials and escape the host immune system. Thus, the refractory nature of biofilm-related infections (BRIs) still represents a great challenge for physicians and is a serious health threat worldwide. Despite its importance, the microbiological diagnosis of a BRI is still difficult and not routinely assessed in clinical microbiology. Moreover, biofilm bacteria are up to 100–1000 times less susceptible to antibiotics than their planktonic counterpart. Consequently, conventional antibiograms might not be representative of the bacterial drug susceptibility in vivo. The timely recognition of a BRI is a crucial step to directing the most appropriate biofilm-targeted antimicrobial strategy.