Penile prosthesis biofilm formation and emerging therapies against them

50 years of inflatable penile implants: Where do we stand in France?

INTRODUCTION

With 50 years' experience, inflatable penile implants are the preferred option for erectile dysfunction refractory to pharmacological and mechanical treatment. Technical and surgical improvements have optimized patient success and satisfaction. However, multi-factorial dissatisfaction persists.

OBJECTIVE

The aim of this study is to provide an overview of available technological improvements and innovations, as well as the perioperative management and complications of inflatable penile implant surgery.

METHOD

A literature review was carried out over the last twenty years to answer 4 questions: what are the different inflatable penile implants available in 2023, for which indications, results and complications.

RESULTS

Four companies propose inflatable penile implants in France. The main improvements have been in the various components of the prosthesis with better cylinder extension, more ergonomic reservoirs, and more manageable pumps, leading to a better durability. Indications have been extended to patients suffering from Peyronie's disease and in emergency cases of priapism. In response to demand from the transgender population, specific phalloplasty implants have been developed. New options are being developed for difficult cases of retracted penis. Results show a high satisfaction rate. Currently the main challenge is the management of infection with the development of rescue protocols using antibiotics to preserve implants - or replace them in a single operation.

CONCLUSION

After 50years' experience, improvements in penile implants led to effective, satisfactory and safe treatment and can be proposed in new indications. Further development is sill necessary to offer solutions in difficult cases.

Emerging strategies for the prevention of bacterial biofilm in prosthetic surgery

Penile prosthesis implantation is an effective treatment for erectile dysfunction (ED) with high patient satisfaction and effectiveness. Unfortunately, infections remain a dreaded complication, often necessitating device removal and imposing a substantial healthcare cost. Biofilms are communities of microorganisms encased in a self-produced polymeric matrix that can attach to penile prostheses. Biofilms have been demonstrated on the majority of explanted prostheses for both infectious and non-infectious revisions and are prevalent even in asymptomatic patients. Biofilms play a role in microbial persistence and exhibit unique antibiotic resistance strategies that can lead to increased infection rates in revision surgery. Biofilms demonstrate physical barriers through the development of an extracellular polymeric substance (EPS) that hinders antibiotic penetrance and the bacteria within biofilms demonstrate reduced metabolic activity that weakens the efficacy of traditional antibiotics. Despite these challenges, new methods are being developed and investigated to prevent and treat biofilms. These treatments include surface modifications, biosurfactants, tissue plasminogen activator (tPA), and nitric oxide (NO) to prevent bacterial adhesion and biofilm formation. Additionally, novel antibiotic treatments are currently under investigation and include antimicrobial peptides (AMPs), bacteriophages, and refillable antibiotic coatings. This article reviews biofilm formation, the challenges that biofilms present to conventional antibiotics, current treatments, and experimental approaches for biofilm prevention and treatment.

A multicenter investigation examining timing of penile prosthesis infection management and responsible organisms

The purpose of this investigation was to examine the timing of penile prosthesis infection management by different responsible organisms. A retrospective cohort study was performed of patients who underwent penile prosthesis salvage or explant procedures due to a suspected infection between 2001 and 2018. The cohort consisted of 216 patients from 33 different facilities and six countries. The most common primary organisms responsible for device infections included, Gram-positives (31.5%), no growth cultures (30.6%), Gram-negatives (22.2%), fungal (11.6%), and anaerobic organisms (4.2%). Overall, median time to infection was 1.8 (interquartile range [IQR]: 1.0-3.0) months for all patients. Median time to infection management was similar between responsible organisms: 1.0 (IQR: 1.0-2.3) months for Gram-negatives and 2 months for Gram-positives (IQR: 1.0-1.4), fungal (IQR: 1.0-5.0), anaerobes (IQR: 1.0-2.5), and no growth cultures (IQR: 1.0-3.0, p = 0.56). Median time to infection management was significantly shorter among patients who received aminoglycoside/vancomycin prophylaxis (1.5 months, IQR: 1.0-2.5, p < 0.01) compared to other antibiotic groups. Median time to infection management was significantly longer for patients managed with a three-piece inflatable implant salvage procedure (2.8 months, IQR: 1.0-5.0, p = 0.02) compared to other salvage procedures. Conventional wisdom surrounding early versus late penile prosthesis infections should largely be abandoned. More than half of penile prosthesis infections are surgically managed within 2 months of initial device placement.

The International Penile Prosthesis Implant Consensus Forum: clinical recommendations and surgical principles on the inflatable 3-piece penile prosthesis implant

Despite significant scientific advances in the modern three-piece inflatable penile prosthesis implant surgery, it is not without surgical risks and can carry additional cosmetic and psychosocial consequences in poorly selected and consented individuals. To address this problem, an international group of key opinion leaders and high-volume prosthetic surgeons reviewed the current guidelines and clinical evidence, discussed their experiences, and formed a consensus regarding inflatable penile prosthesis surgery. The findings of this consensus panel were presented at the 17th biennial Asia Pacific Society of Sexual Medicine scientific meeting. The experts concluded that proper patient selection, informed consent and strict adherence to safe surgical principles are important to optimize clinical outcomes. Furthermore, most intraoperative complications, if recognized, can be addressed intraoperatively to enable placement of the device at the time of initial surgery. Men with significant corporal fibrosis due to Peyronie's disease, prior prosthesis explantation and priapism, and men who have undergone construction of a neophallus, as well as men who receive concurrent continence surgery, are complex cases requiring additional care and advanced techniques to obtain optimal surgical outcomes. Variability in patient care - in terms of postoperative antibiotic use, pain management, scrotal care, and cycling of the penile prosthesis implant - must be reduced to enable optimization and assessment of outcomes across patient groups.

A scoping review of penile implant biofilms-what do we know and what remains unknown?

Background

Penile prosthesis (PP) is a gold standard for treatment of erectile dysfunction given its reliability and efficacy. Infection remains the most feared complication of prosthetic surgery, which usually results in device removal, and places a significant economic burden on the healthcare system. While biofilms have shown to support the persistence of microorganisms, the degree by which this matrix is truly pathogenic remains unknown given its high prevalence even in asymptomatic patients. We aim to review and summarize the current literature pertaining to biofilm formation in the setting of PP surgeries in clinically infected and non-infected cases.

Methods

Searches were performed in the MEDLINE online database through PubMed using a combination of keywords "penile prosthetic" OR "penile prosthesis" OR "penile implant" AND "biofilm" OR "revision" OR "removal" OR "infection" OR "explant". Eleven articles met inclusion criteria. There were only three studies that explicitly listed the number of biofilms identified in their cohort, but we also included eight articles that mentioned swabbing and culturing of any bacterial biofilm during revision procedures for both clinically infected and non-infected implants.

Results

Infected PP yielded a 11-100% rate of biofilm presence, while non-infected PP yielded a 3-70% rate of biofilm presence. Time to reoperation from initial PP placement were also largely variable, ranging from 2 weeks to over 2 years. Coagulase-negative staphylococcus (i.e., Staphylococcus epidermidis) were the most commonly reported organisms among non-infected implants, however, newer studies have identified a change towards more virulent organisms.

Conclusions

Since the advent of PP surgery, diabetes control, revision washout protocols and antibiotic-impregnated devices have led to an overall decrease in biofilm formation and infectious complications. There is an overall paradigm shift in microbial profiles with more virulent organisms, such as Escherichia coli, Pseudomonas aeruginosa, Enterococcus species, and even fungal species beginning to replace the more common coagulase-negative staphylococcal species, especially in clinically infected implants. Additional studies are necessary to define the significance of bacterial presence in biofilms using impactful technologies such as next-generation sequencing. Currently, preliminary and experimental biofilm-control strategies are also underway to further address this clinical issue.

Evaluation of Bacteria in a Novel In Vitro Biofilm Model of Penile Prosthesis

BACKGROUND

Delayed infection, thought to be due to gradual biofilm formation, remains a feared complication after inflatable penile prosthesis (IPP) insertion. Understanding and preventing biofilm formation is necessary to prevent infections.

AIM

To develop an in vitro model and compare growth of biofilm by different bacteria on IPPs and evaluate the anti-infective efficacy of the Coloplast Titan and AMS 700 InhibiZone.

METHODS

Sterile IPPs (Coloplast) were cut into rings and incubated with S. epidermidis, S. aureus, P. aeruginosa, A. baumannii, or K. pneumoniae cultures in tryptic soy broth (TSB) (4 hour) to ensure adequate bacteria attachment, and then in only TSB (120 hours) to allow for biofilm formation. Rings were fixed with ethanol and biofilm measured by spectrophotometer (OD570) after crystal violet staining. This methodology was repeated for S. epidermidis and P. aeruginosa with Coloplast rings dipped in 10 ml of a 10 mg/ml Rifampin, 1 mg/ml Gentamicin, and deionized water solution and undipped AMS InhibiZone rings. Crystal violet assay (OD570) was repeated after incubation within bacteria (2 hour), and then only TSB (120 hours).

OUTCOMES

The primary outcome of the study was OD570 readings, indirectly measuring biofilm mass on implant rings.

RESULTS

S. epidermidis, S. aureus, A. baumannii, P. aeruginosa, and K. pneumoniae all formed significant biofilm. P. aeruginosa showed the strongest predilection to grow biofilm on IPPs. P. aeruginosa also formed significant biofilm on antibiotic-treated Coloplast and AMS rings, while S. epidermidis was inhibited. No significant difference was found in biofilm inhibition between the implants.

CLINICAL TRANSLATION

Our findings suggest gram-negative bacteria may form biofilm more proficiently and quickly on IPPs than gram-positive organisms. Commonly used antibiotic treatments on IPPs may be effective against S. epidermidis but not against P. aeruginosa biofilm formation.

STRENGTHS & LIMITATIONS

This is the first study comparing biofilm formation by different bacteria organisms on IPPs and the inhibitive ability of Coloplast and AMS implants against biofilm formation. Clinical data on organisms responsible for infected IPPs is needed to determine the clinical relevance of our findings.

CONCLUSION

Our novel in vitro model of biofilm formation of IPPs evaluated the effect of a gentamicin/rifampin antibiotic dip on Coloplast Titan implants and the anti-infective capacity of the minocycline/rifampin precoated AMS 700 InhibiZone against S. epidermidis and P. aeruginosa. P. aeruginosa was able to grow on both antibiotic-treated implants, with no significant difference, and should continue to be a specific target of investigation to reduce delayed post-operative IPP infections. Narasimman M, Ory J, Bartra SS, et al. Evaluation of Bacteria in a Novel In Vitro Biofilm Model of Penile Prosthesis. J Sex Med 2022;19:1024-1031.

Prevention of Penile Prosthesis Infection

INTRODUCTION

Management protocols for treatment of severe erectile dysfunction have changed little in the last 20 years. Most algorithms consider penile prostheses as the last option of treatment in patients who have failed medical management. Despite multiple advances in current devices, prosthetic infection remains the most feared complication by implanting surgeons and patients. This report tries to make a compilation of the factors that can be impacted to prevent penile implant infections, and to make penile implantation a safer and more reliable way to solve an erection deficit.

PURPOSE OF REVIEW

List events related to the surgical act (pre-operative, intra-operative, and post-operative) that are related to the risk of infection to contextualize possible actions/measures used to avoid prosthetic infection.

RECENT FINDINGS

The impact of coated implants on reduction of infection rates. The recommendation to use chlorhexidine-based solutions over iodine solution for preoperative skin preps. Appears to be no difference in infection rates according to the approach chosen by the surgeon (infrapubic vs penoscrotal). The change in the microbial colonies that are colonizing implants in recent years are dramatic. Lack of evidence of which solutions to use for salvage or revision washout surgery: Chemical eradication or mechanical lavage cleansing?. Despite the importance of metabolic control in the literature, there is a disparity in exact glycemic values ​prior to the intervention in our literature. Factors such as preparation of the operative site, presence of comorbidities or previous surgeries, surgical time, or additional maneuvers during surgery can negatively impact the final result of penile prosthetic surgery.

Penile prosthesis salvage: a historical look at the Mulcahy technique and a review of the latest literature

Historically, management of inflatable penile prosthesis infection was explantation of the device with delayed reimplantation at a later date. In 1991, this paradigm was challenged when early attempts at washout and immediate salvage proved successful. The clinical experiences and data generated over the past 30 years have allowed implanters to refine their salvage procedures to improve patient outcomes. In this article, we review the original Mulcahy technique for salvage and discuss updates to this protocol based on recent data.

Penile implant surgery-managing complications

Penile prosthesis surgery represents the end-stage treatment for erectile dysfunction. It is conventionally used only in cases of erectile dysfunction refractory to pharmacological treatments or vacuum constriction devices. Contemporary literature suggests that penile prothesis surgery is associated with a high satisfaction rate and a low complication profile. However, it must be appreciated that the complications of surgery can have devastating consequences on a patient’s quality of life and satisfaction and include infection, prosthesis malfunction, penile corporal perforation and penile length loss. Several factors – such as appropriate patient selection, methodical preoperative assessment and patient optimization, specific intraoperative protocols and postoperative recommendations – can reduce the risk of surgical complications. This narrative review discusses the diagnosis and management of both intraoperative and postoperative complications of penile prosthesis surgery.

Updates in penile prosthesis infections

Inflatable penile prostheses are an important tool in the treatment of medically refractory erectile dysfunction. One of the major complications associated with these prostheses is infections, which ultimately require device explanation and placement of a new device. Over the past several decades, significant work has been done to reduce infection rates and optimize treatment strategies to reduce patient morbidity. This article reviews the current state of knowledge surrounding penile prosthesis infections, with attention to the evidence for methods to prevent infection and best practices for device reimplantation.

Treatment of Penile Prosthesis Implant's Infection

INTRODUCTION

Penile prosthesis implant is a safe and effective option in erectile dysfunction patients, being implant procedures safe with a low risk of infection. However, when infection occurs, it represents a concrete problem for both surgeon and patient.

METHODS

This is a comprehensive review of all issues relating to prosthesis infection, including causes and risk factors, methods of prevention, and management. We analyzed all preoperative and perioperative factors, which can play a role in infection of the device.

RESULTS

Infection of penile prosthesis implant is hard to manage and correct. While the incidence of infection following first implant is up to 3%, in cases of re-implant surgery, the rate can reach as high as 18%. Many articles were found addressing prevention and treatment of penile prosthesis infection, and many analyzed all relevant pre- and perioperative factors associated with penile prosthesis implant. Although such factors have been well studied, there is no clear consensus worldwide on certain topics.

CONCLUSIONS

Penile prosthesis implant is a safe and effective option. Despite infection is a rare event, surgeons should follow strictly pre-, intra- and postoperative recommendations in order to reduce the risk of device's infection. An appropriate antibiotic therapy should be tailored on patient's characteristics and pathogens isolated.

The future of penile prostheses for the treatment of erectile dysfunction

Penile prostheses (both inflatable and malleable) are standard care in the management of erectile dysfunction (ED). Introduced over 45 years ago, modern penile implants have evolved greatly during that period of time and now represent the cutting edge in materials science and function. Despite the introduction of highly effective oral pharmacotherapy for ED, these devices have remained relevant and will almost certainly remain so for the foreseeable future. Despite their high degree of efficacy, there is always potential for further improvements in both implants themselves and the surgical techniques and processes used for their placement. In this manuscript we speculate on the future of penile implants, based in large part on the historical perspective and recent developments in the implant surgery space. We include recommendations on future technical innovations, post-operative management, and novel implant designs that may revolutionize the future management of ED.

Infectious Adverse Events Following the Placement of a Penile Prosthesis: A Systematic Review

INTRODUCTION

Infection remains a prominent concern following penile implantation. Recognition of the risk factors for infection may help to guide surgeons toward reducing the risk of prosthetic contamination.

AIM

To gain a further understanding of infectious adverse events following penile prosthesis, we performed a systematic literature review.

METHODS

As part of the 2018 American Urological Association Erectile Dysfunction Clinical Guidelines and with the support of the American Urological Association, we performed a comprehensive review of the PubMed, Embase, and Cochrane databases to search for eligible articles published between January 1, 1965, and July 20, 2016, to identify articles reporting infectious adverse events following prosthesis placement.

MAIN OUTCOME MEASURE

The main outcome measure was infectious adverse events following penile prosthesis placement.

RESULTS

Ninety-one articles reporting infectious adverse events representing 97 study arms were identified. Prosthetic infection rates ranged from 0% to 24.6% across all series. Inflatable penile prostheses displayed a wider range (0-24.6%) than malleable devices (0-9.1%); the most frequently reported infection rate for inflatable devices was 5% or less. With the advent of device coatings and improved surgical techniques, infectious adverse events have decreased. Infections among diabetic patients also decreased throughout the reviewed body of literature, with the most recent series reporting rates consistent with those of non-diabetic patients. Furthermore, no glycosylated hemoglobin cutoff was found to infer increased or decreased risk of prosthesis infection.

CONCLUSION

Overall penile prosthetic infectious adverse events have decreased as surgical techniques have improved and the use of antimicrobial coating has gained in popularity. These advances have demonstrated significant benefits for all patients, particularly diabetic patients who experience infection rates similar to those of non-diabetic patients in recent reports. Further technological advancements for the prevention of biofilm formation is warranted. Mahon J, Dornbier R, Wegrzyn G, et al. Infectious Adverse Events Following the Placement of a Penile Prosthesis: A Systematic Review. Sex Med Rev 2020;8:348-354.