In Vitro Evaluation of Common Antimicrobial Solutions Used for Breast Implant Soaking and Breast Pocket Irrigation-Part 2: Efficacy Against Biofilm-Associated Bacteria

Biologic Response With and Without Acellular Dermal Matrix in Breast Reconstruction

Background

Acellular dermal matrices (ADMs) are biologic meshes commonly used in implant-based breast reconstruction (IBBR) procedures to provide implant support and coverage. Although the etiology is not well understood, increasing preclinical and clinical evidence suggest that ADMs may help prevent capsular contracture, a frequent complication of IBBR, by modulating the inflammatory response in the tissue surrounding breast implants. The objective of this narrative review is to discuss the evidence supporting the role of inflammation in capsular contracture following IBBR without ADM, and to characterize the potential mechanism(s) by which ADMs may reduce the incidence of capsular contracture in IBBR.

Methods

Relevant studies in English published up to December 31, 2023, were identified from 4 databases (BIOSIS Previews, Embase, MEDLINE, and Northern Light Life Sciences Conference Abstracts) using search terms such as "breast" and "capsular contracture."

Results

This review discusses the potential factors (eg, expander-to-implant reconstruction, diminished collagen integrity, postmastectomy radiation therapy, surface of implant, plane of placement, incision type, hematoma, seroma, postoperative infection, and biofilm) and emerging biomarkers (eg, NRG1, IL-8, TIMP-1, TIMP-2, TIMP-4, MMP2, MMP12, ACAN, SAA1, TNFSF11, and hyaluronan) that may be able to predict capsular contracture. The available evidence that tissue integration of ADMs modulates the wound healing process and inflammation, and the available clinical evidence, which indicates that ADMs may decrease rates of capsular contracture following postmastectomy radiation therapy, are summarized.

Conclusions

The studies summarized in this review suggest that ADMs may reduce the likelihood of capsular contracture in IBRR compared with no ADM use.

Preventing Bacterial Contamination of Breast Implants Using Infection Mitigation Techniques: An In Vitro Study

BACKGROUND

Bacterial contamination of implants has been linked to biofilm formation and subsequent infection, capsular contracture, and breast implant-associated anaplastic large cell lymphoma. Reducing contamination during implant insertion should therefore reduce biofilm formation disease sequelae.

OBJECTIVES

The aim of this study was to compare levels of contamination between preventative techniques.

METHODS

A model to simulate the passage of implants through a skin incision was designed that utilized a sterile textured polyvinyl plastic sheet contaminated with Staphylococcus epidermidis. In the first stage of the polyvinyl contamination model, implants were subject to infection-mitigation techniques and passed through the incision, then placed onto horse blood agar plates and incubated for 24 hours. In the second stage of the study the same contamination was applied to human abdominal wall specimens. A 5 cm incision was made through skin and fat, then implants were passed through and levels of contamination were measured as described.

RESULTS

Smooth implants grew a mean of 95 colony-forming units (CFUs; approximately 1 CFU/cm2) and textured implants grew 86 CFUs (also approximately 1 CFU/cm2). CFU counts were analyzed by the Mann-Whitney U-test which showed no significant difference between implant types (P < .05); independent-sample t-tests showed a significant difference. The dependent-variable techniques were then compared as groups by one-way analysis of variance, which also showed a significant reduction compared with the control group (P < .01).

CONCLUSIONS

This in vitro study has shown the effectiveness of antiseptic rinse and skin/implant barrier techniques for reducing bacterial contamination of breast implants at the time of insertion.

Incidental Bystander or Essential Culprit: A Systematic Review of Bacterial Significance in the Pathogenesis of Breast Implant-Associated Anaplastic Large Cell Lymphoma

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a distinct subtype of T-cell non-Hodgkin lymphoma that arises in the context of prolonged exposure to textured breast implants. The intent of this manuscript is to explore whether the bacterial presence in biofilms on these implants is a mere incidental finding or plays a pivotal role in the pathogenesis of BIA-ALCL. Our goal is to delineate the extent of bacterial involvement, offering insights into potential underlying mechanisms, and establishing future research priorities aimed at resolving the remaining uncertainties surrounding this complex association. A comprehensive systematic review of several databases was performed. The search strategy was designed and conducted by an experienced librarian using controlled vocabulary with keywords. The electronic search identified 442 publications. After evaluation, six studies from 2015 to 2021 were included, encompassing 201 female patients aged 23 to 75. The diagnosis span post-implantation ranged from 53 to 135.6 months. Studies consistently found bacteria near breast implants in both BIA-ALCL cases and controls, with varied microbial findings. Both BIA-ALCL cases and controls exhibited the presence of specific bacteria, including Pseudomonas aeruginosa, Klebsiella oxytoca, Staphylococcus aureus, and Ralstonia spp., without any statistically significant differences between groups. The use of antiseptic and antimicrobial agents during implant insertion did not demonstrate any impact on reducing or altering the risk of developing BIA-ALCL. Our systematic review reveals that the current evidence is inadequate to link bacterial etiology as a central factor in the development of BIA-ALCL. The limitations in the existing data prevent a complete dismissal of the role of biofilms in its pathogenesis. The observed gap in knowledge underscores the need for more focused and comprehensive research, which should be structured in a multi-faceted approach. Initially, this involves the utilization of sophisticated genomic and proteomic methods. Following this, it is crucial to delve into the study of immunological reactions specifically induced by biofilms. Finally, this research should incorporate extended observational studies, meticulously tracking the evolution of biofilm development and its correlation with the emergence of BIA-ALCL. In light of the inconclusive nature of current findings, further investigation is not only justified but urgently needed to clarify these unresolved issues.

Betadine Soaking of Silicone Coupons Minimally Impacts Acellular Dermal Matrix Incorporation in a Preclinical Primate Model

BACKGROUND

Microbial pathogens local to prosthetic breast devices may promote infection, inflammation, and capsular contracture. Although antimicrobial solutions have been used, their effects on human acellular dermal matrix (HADM) incorporation when used with prosthetic devices are unknown. The authors' objective was to histologically assess the effect of 10% povidone iodine (PI)-saturated tissue expander (TE) exposure on HADM biological response in a primate model. They hypothesized that PI exposure would not negatively affect the HADM biological response.

METHODS

Samples (1.5 × 1.5 cm) from smooth silicone TEs were saturated in saline or PI for 2 minutes and sutured to HADM to create HADM/TE constructs. Primates implanted subcutaneously with saline ( n = 9) and PI-treated HADM/TE ( n = 9) construct pairs were evaluated histologically for biological response after 2 or 4 weeks by means of a host response scoring scale (1 to 9), including recellularization, neovascularization, and inflammation. Inflammatory cells (eosinophils, lymphocytes, neutrophils, histiocytes, foreign-body giant cells) and evidence of HADM remodeling (fibroblasts, vessels) were further evaluated by means of a cell-specific scoring scale (0 to 4) and corroborated by immunostaining (CD3, CD20, CD68, FSP-1, collagen type IV).

RESULTS

Mean histology scores were similar between saline- and PI-exposed HADM at 2 weeks (5.3 ± 0.9 and 5.6 ± 0.5; P = 0.52) and 4 weeks (4.6 ± 1.0 and 4.2 ± 0.9; P = 0.44). There was no difference in inflammatory cell presence at 2 and 4 weeks between groups. Fibroblast infiltration differences were insignificant between groups but exhibited trends toward an increase between time points for saline (1.6 ± 0.7 to 1.8 ± 0.8) and PI (1.3 ± 0.8 to 1.8 ± 1.0) groups, suggesting HADM incorporation over time.

CONCLUSION

Data suggest that HADM exposure to PI-treated TEs does not negatively affect inflammation, vascularization, recellularization, incorporation, or host response to HADM in this model.

CLINICAL RELEVANCE STATEMENT

PI is a surgical pocket irrigant used to address bacterial colonization, but its impact on ADM incorporation is unknown. This study demonstrates similar biologic response to ADMs adjacent to PI- or saline-saturated TEs in a primate model.

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.

Comparing the efficacy of antimicrobial pocket-irrigation protocols in an in vivo breast implant infection model

BACKGROUND

Breast implant infection and biofilm formation are major concerns in reconstructive and esthetic breast surgery, with significant medical and economic consequences. Staphylococcus is the common pathogen, with rapidly increasing rates of methicillin-resistant Staphylococcus aureus (MRSA). There is no consensus on prevention practices. This study compares the effect of several pocket irrigation and antibiotic prophylaxis regimens on implant colonization and biofilm formation in an established rat model of MRSA-infected silicone breast implants.

METHODS

Silicone discs were inserted in a sub-pectoral pocket in 57 rats (114 implants). Implant infection was induced by injection of free planktonic MRSA into the surgical pocket. Rats were allocated to study groups treated by different antimicrobial protocols: pocket irrigation with vancomycin, povidone-iodine, or saline. Each group was divided into subgroups treated with or without additional peri-operative systemic vancomycin. Implant colonization or overt infection was assessed at post-operative day 14 both clinically and by cultures.

RESULTS

Pocket irrigation with vancomycin prevented contamination in 87% of implants. Irrigation and systemic vancomycin prevented contamination in 100% of implants with no difference between a single preoperative dose and a 48-h regimen. Systemic vancomycin alone or irrigation with povidone-iodine alone resulted in 100% contamination rates.

CONCLUSIONS

In this in vivo model, combination of systemic vancomycin with vancomycin pocket irrigation was the most effective regimen, preventing contamination in 100% of implants. Continuation of post-operative antibiotic treatment showed no added advantage.

The Role of Microorganisms in the Development of Breast Implant-Associated Anaplastic Large Cell Lymphoma

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a variant of anaplastic large cell lymphoma (ALCL) associated with textured-surface silicone breast implants. Since first being described in 1997, over 1100 cases have been currently reported worldwide. A causal relationship between BIA-ALCL and textured implants has been established in epidemiological studies, but a multifactorial process is likely to be involved in the pathogenesis of BIA-ALCL. However, pathophysiologic mechanisms remain unclear. One of the hypotheses that could explain the link between textured implants and BIA-ALCL consists in the greater tendency of bacterial biofilm in colonizing the surface of textured implants compared to smooth implants, and the resulting chronic inflammation which, in predisposed individuals, may lead to tumorigenesis. This review summarizes the existing evidence on the role of micro-organisms and rough surface implants in the development of BIA-ALCL. It also provides insights into the most updated clinical practice knowledge about BIA-ALCL, from clinical presentation and investigation to treatment and outcomes.

Pharmacological Approaches for the Prevention of Breast Implant Capsular Contracture

Capsular contracture is a common complication associated with breast implants following reconstructive or aesthetic surgery in which a tight or constricting scar tissue capsule forms around the implant, often distorting the breast shape and resulting in chronic pain. Capsulectomy (involving full removal of the capsule surrounding the implant) and capsulotomy (where the capsule is released and/or partly removed to create more space for the implant) are the most common surgical procedures used to treat capsular contracture. Various structural modifications of the implant device (including use of textured implants, submuscular placement of the implant, and the use of polyurethane-coated implants) and surgical strategies (including pre-operative skin washing and irrigation of the implant pocket with antibiotics) have been and/or are currently used to help reduce the incidence of capsular contracture. In this article, we review the pharmacological approaches-both commonly practiced in the clinic and experimental-reported in the scientific and clinical literature aimed at either preventing or treating capsular contracture, including (i) pre- and post-operative intravenous administration of drug substances, (ii) systemic (usually oral) administration of drugs before and after surgery, (iii) modification of the implant surface with grafted drug substances, (iv) irrigation of the implant or peri-implant tissue with drugs prior to implantation, and (v) incorporation of drugs into the implant shell or filler prior to surgery followed by drug release in situ after implantation.

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

Background

In the practice of breast augmentation and reconstruction, implant irrigation with various solutions has been widely used to prevent infection and capsular contracture, but to date, there is no consensus on the optimal protocol to use. Recently, application of povidone iodine (PI) for 30 min has shown in vitro to be the most effective irrigating formula in reducing contamination in smooth breast implants. However, as 30 min is not feasible intraoperatively, it is necessary to determine whether shorter times could be equally effective as well as to test it in both smooth and textured implants.

Methods

We tested the efficacy of 10% PI at 1', 3', and 5' against biofilms of 8 strains (2 ATCC and 6 clinical) of Staphylococcus spp. on silicone disks obtained from Mentor^® and Polytech^® implants of different textures. We analyzed the percentage reduction of cfu counts, cell viability and bacterial density between treatment (PI) and control (sterile saline, SS) groups for each time of application. We consider clinical significance when > 25% reduction was observed in cell viability or bacterial density.

Results

All textured implants treated with PI at any of the 3 exposure times reduced 100% bacterial load by culture. However, none of the implants reached enough clinical significance in percentage reduction of living cells. Regarding bacterial density, only 25-50 μm Polytxt^® Polytech^® implants showed significant reduction at the three PI exposure times.

Conclusion

PI is able to inhibit bacterial growth applied on the surface of breast implants regardless of the exposure time. However, no significant reduction on living cells or bacterial density was observed. This lack of correlation may be caused by differences in texture that directly affect PI absorption.

Current Concepts in Capsular Contracture: Pathophysiology, Prevention, and Management

Over 400,000 women in the United States alone will have breast implant surgery each year. Although capsular contracture represents the most common complication of breast implant surgery, surgeons continue to debate the precise etiology. General agreement exists concerning the inflammatory origin of capsular fibrosis, but the inciting events triggering the inflammatory cascade appear to be multifactorial, making it difficult to predict why one patient may develop capsular contracture while another will not. Accordingly, researchers have explored many different surgical, biomaterial, and medical therapies to address these multiple factors in an attempt to prevent and treat capsular contracture. In the current paper, we aim to inform the reader on the most up-to-date understanding of the pathophysiology, prevention, and treatment of capsular contracture.

Efficacy of a novel antimicrobial hydrogel for eradication of Staphylococcus epidermidis, Staphylococcus aureus and Cutibacterium acnes from preformed biofilm and treatment performance in an in vivo MRSA wound model

BACKGROUND

Bacterial biofilm formation is a complicating factor in the antimicrobial treatment of bacterial infections.

OBJECTIVES

In this study, we assessed the impact of a novel hydrogel with the active antimicrobial compound JBC 1847 on eradication of preformed biofilms of Staphylococcus epidermidis, Cutibacterium acnes and MRSA in vitro, and evaluated the in vivo efficacy of MRSA wound treatment.

METHODS

Biofilms were exposed to JBC 1847 for 24 h and subsequently the treatments were neutralized and surviving biofilm-associated bacteria recovered and enumerated. The efficacy of the hydrogel on post-treatment load of MRSA was determined in a murine model of MRSA wound infection, and skin samples of the infected mice were examined histologically to evaluate the degree of healing.

RESULTS

A concentration-dependent eradication of biofilm-embedded bacteria by JBC 1847 was observed for all three pathogens, and the hydrogel caused a greater than four log reduction of cfu in all cases. In the mouse model, treatment with the hydrogel significantly reduced the cfu/mL of MRSA compared with treatment of MRSA-infected wounds with pure hydrogel. Histopathological analysis of the wounds showed that the JBC 1847 treatment group had a lower grade of inflammation, a higher mean score of re-epithelization and higher mean scores of parameters assessing the maturity of the newly formed epidermis, compared with both the fusidic acid 2% and vehicle treatment groups.

CONCLUSIONS

The novel hydrogel shows promising results as a candidate for future wound treatment, likely to be highly effective even in the case of biofilm-complicating infected wounds.