Infection Prevention Considerations for Complex Penile Prosthesis Recipients

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.

Microorganism Profiles of Penile Prosthesis Removed for Infection, Erosion, and Mechanical Malfunction Based on Next-Generation Sequencing

BACKGROUND

Next-generation sequencing (NGS) is an emerging technology that may allow for more sensitive and sophisticated microbial testing of the microbiota of penile prostheses (PP).

AIM

To describe the microorganism profiles of PP explanted for infection, erosion, and mechanical malfunction using NGS.

METHODS

All patients who underwent PP removal by two physicians at two institutions were identified. Differences in alpha diversity (ie, number of species detected, species diversity across samples) and microbiome compositional profiles (Bray-Curtis community dissimilarities) across samples were assessed using ANOVA and PERMANOVA, respectively.

OUTCOMES

Number of species detected, species diversity across samples, and microbiome compositional profiles.

RESULTS

A total of 83 patients who underwent device removal for infection (n = 8, 10%), erosion (n = 5, 6%), and mechanical malfunction (n = 70, 84%) were included. When considering all devices, 56% (n = 48) of NGS and 29% (n = 24) of standard cultures resulted positive for presence of microorganisms. Culture only detected the most abundant NGS species in 62.5% (n = 5) of infected devices. Species richness and microbiome compositional profiles varied by surgical indication, but not by age, race, diabetes status, or implant duration. Most frequent organisms by surgical indication were Pseudomonas aeruginosa (infection), Staphylococcus epidermidis (erosion), and Escherichia coli (mechanical malfunction). The highest relative abundance organisms were P aeruginosa (infection), Corynebacterium jeikeium (erosion), and E coli (mechanical malfunction).

CLINICAL IMPLICATIONS

Identifying microbiome profiles of PP removed for infection, erosion, and mechanical malfunction may guide the selection of peri-operative antibiotics and PP antibiotic coatings or hydrophilic dip solutions for each individual scenario.

STRENGTHS AND LIMITATIONS

While this is the first study to utilize next-generation sequencing to evaluate penile prosthesis biofilm, the clinical significance of these findings has yet to be determined. A prospective, randomized trial aimed at evaluating the clinical significance of NGS in patients with PP infection is currently underway.

CONCLUSION

NGS testing identified distinct microbiome profiles of PP removed for infection, erosion, and mechanical malfunction. Chung PH, Leong JY, Phillips CD, Henry GD. Microorganism Profiles of Penile Prosthesis Removed for Infection, Erosion, and Mechanical Malfunction Based on Next-Generation Sequencing. J Sex Med 2022;19:356-363.

Do Antifungals and Local Anesthetic Affect the Efficacy of Antibiotic Dipping Solution?

BACKGROUND

The rates of infection after inflatable penile prosthesis (IPP) range from 1% to 3%; however, with changes in antibiotic practice intraoperatively and the incorporation of local anesthetic dips, it is unclear whether this incidence of infection is affected.

AIM

To evaluate whether the utilization of local anesthetic dips and antifungal solutions affect the efficacy of previously established dips across multiple species and strains.

METHODS

Strains of four different species of bacteria and one fungus were prepared in a standardized confluency. A standardized, and sterile protocol was used to punch out 6mm circular discs from the reservoir of a Coloplast Titan device. The discs were submerged in a standardized concentration of antimicrobials (combinations of Bactrim, Rifampin + Gentamicin, Vancomycin, Zosyn, and Amphotericin B) and plated. The zone of inhibition (ZOI) was measured at 24, 48, and 72 hours. Five repetitions of each organism was performed (>1700 discs), and the mean ZOI was calculated. Saline and DMSO were used as control on each plate.

OUTCOMES

Main outcome was the ZOI identified with each antibiotic solution, and the secondary outcome was the efficacy of the antibiotic over the course of 72 hours.

RESULTS

Difference in antibiotic efficacy was seen when each bacterial species was evaluated separately, with rifampin and gentamicin having less efficacy towards all organisms other than S. epidermidis. When looking specifically at the Candida species, amphotericin B was significantly better than other antibiotic solutions. In regards to efficacy of antibiotics over 72 hours, all treatment groups showed a decrease in ZOI over time. However, treatment groups that included rifampin demonstrated the ability to inhibit S. aureus and S. epidermidis over the 72-hour period.

CLINICAL IMPLICATIONS

To improve clinical practice and alleviate concerns that incorporation of local anesthetic and antifungals may decrease the efficacy of antibiotic solutions.

STRENGTHS AND LIMITATIONS

A major strength of the study is that it is the most robust and scientifically sound study performed on this topic with approximately 1700 repetitions. It is also the first study of its kind to include a wide spectrum of bacterial and fungal strains and antibiotic solutions along with temporal data on drug elution over a 72-hour period. A limitation of the study is the in vitro model, and this needs to be validated in a clinical setting.

CONCLUSIONS

Dipping prosthetics in antifungal and local anesthetic does not decrease the efficacy of the antimicrobials. The drug elution capabilities of the hydrophilic coating lasts primarily for 24-48hours. Mishra K, Bukavina L, Long L, et al. Do Antifungals and Local Anesthetic Affect the Efficacy of Antibiotic Dipping Solution?. J Sex Med 2021;18:966-973.

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.

Update on Intraoperative Cultures, Biofilms, and Modifiable Factors During Revision of Clinically Non-Infected Penile Implants

INTRODUCTION

Penile implants have a limited lifespan, and as the population using inflatable penile prostheses ages, revision surgery has become increasingly common. Devices are frequently cultured during non-infectious revision surgeries, providing a burgeoning of evidence of positive cultures without clinical infection. However, the clinical significance of these cultures remains unclear.

OBJECTIVES

We aim to review the current literature on culture results from revision surgery for clinically non-infected devices and summarize the available data to formulate a synopsis of clinically significant organisms and their significance and modifiable approaches to prosthesis surgery.

METHODS

A literature review was performed on 1 March, 2020 in PubMed and Google Scholar. Search terms centered on penile prosthesis revision surgery, cultures, and infection. Titles and abstracts were reviewed for topical relevance with emphasis placed on literature from the last 20 years. Most publications comprised small case series aside from a single meta-analysis.

RESULTS

Since 1995, seven series have been published examining culture positivity at the time of revision surgery for clinically non-infected devices. Isolated organisms are most commonly from the Staphylococcus genus with Staphylococcus epidermidis being the most frequently isolated organism on clinically non-infected devices. Reported culture positivity rates at the time of revision range between 9.8% and 80%.

CONCLUSION

Current literature pertaining to the clinical significance of culture positivity at the time of revision surgery for clinically non-infected penile prostheses is lacking; however, multiple series do report high rates of culture positivity. This does appear to confer a higher rate of subsequent infection and a lower revision-free survival. Staphylococcus epidermidis is the most commonly isolated organism followed by other members of the Staphylococcus genus. Further studies are needed to determine the impact of modifiable variables or techniques on asymptomatic culture positivity and the ideal technologies for biofilm prevention. Nosé BD, Grimberg DCD, Lentz AC. Update on Intraoperative Cultures, Biofilms, and Modifiable Factors During Revision of Clinically Non-Infected Penile Implants. Sex Med Rev 2021;9:160-168.