Biofilms and their role in infections in urology

Chemical Modification of Tiopronin for Dual Management of Cystinuria and Associated Bacterial Infections

Cystinuria is an inherited autosomal recessive disease of the kidneys of recurring nature that contributes to frequent urinary tract infections due to bacterial growth and biofilm formation surrounding the stone microenvironment. In the past, commonly used strategies for managing cystinuria involved the use of (a) cystine crystal growth inhibitors such as l-cystine dimethyl ester and lipoic acid, and (b) thiol-based small molecules such as N-(2-mercaptopropionyl) glycine, commonly known as tiopronin, that reduce the formation of cystine crystals by reacting with excess cystine and generating more soluble disulfide compounds. However, there is a dearth of simplistic chemical approaches that have focused on the dual treatment of cystinuria and the associated microbial infections. This work strategically exploited a single chemical approach to develop a nitric oxide (NO)-releasing therapeutic compound, S-nitroso-2-mercaptopropionyl glycine (tiopronin-NO), for the dual management of cystine stone formation and the related bacterial infections. The results successfully demonstrated that (a) the antibacterial activity of NO rendered tiopronin-NO effective against the stone microenvironment inhabitants, Escherichia coli and Pseudomonas aeruginosa, and (b) tiopronin-NO retained the ability to undergo disulfide exchange with cystine while being reported to be safe against canine kidney and mouse fibroblast cells. Thus, the synthesis of such a facile molecule aimed at the dual management of cystinuria and related infections is unprecedented in the literature.

Genome Analysis and Antibiofilm Activity of Phage 590B against Multidrug-Resistant and Extensively Drug-Resistant Uropathogenic Escherichia coli Isolates, India

Urinary tract infections (UTIs) are among the most common bacterial infections in humans. Uropathogenic Escherichia coli (UPEC), which are the most frequent agents causing community as well as hospital-acquired UTIs, have become highly drug-resistant, thus making the treatment of these infections challenging. Recently, the use of bacteriophages (or 'phages') against multidrug-resistant (MDR) and extensively drug-resistant (XDR) microorganisms has garnered significant global attention. Bacterial biofilms play a vital role in the pathogenesis of UTIs caused by UPEC. Phages have the potential to disrupt bacterial biofilms using lytic enzymes such as EPS depolymerases and endolysins. We isolated a lytic phage (590B) from community sewage in Chandigarh, which was active against multiple MDR and XDR biofilm-forming UPEC strains. During whole-genome sequencing, the 44.3 kb long genome of phage 590B encoded 75 ORFs, of which 40 were functionally annotated based on homology with similar phage proteins in the database. Comparative analysis of associated phage genomes indicated that phage 590B evolved independently and had a distinct taxonomic position within the genus Kagunavirus in the subfamily Guernseyvirinae of Siphoviridae. The phage disrupted biofilm mass effectively when applied to 24 h old biofilms formed on the Foley silicon catheter and coverslip biofilm models. To study the effect of intact biofilm architecture on phage predation, the biofilms were disrupted. The phage reduced the viable cells by 0.6-1.0 order of magnitude after 24 h of incubation. Regrowth and intact bacterial cells were observed in the phage-treated planktonic culture and biofilms, respectively, which indicated the emergence of phage-resistant bacterial variants. The phage genome encoded an endolysin which might have a role in the disruption and inhibition of bacterial biofilms. Moreover, the genome lacked genes encoding toxins, virulence factors, antibiotic resistance, or lysogeny. Therefore, lytic phage 590B may be a good alternative to antibiotics and can be included in phage cocktails for the treatment of UTIs caused by biofilm-forming MDR and XDR UPEC strains.

Catheter-Associated Urinary Tract Infection (CAUTI)

One of the most prevalent health-related illnesses globally is catheter-associated urinary tract infection (CAUTI). CAUTIs account for almost half of all hospital-acquired diseases. Most of the healthcare-acquired urinary tract infections result from catheter tubes implantation. These tubes connect a collecting system and the urinary bladder via the urethra. These are known as indwelling urinary catheters. The length of catheterization has a key role in starting bacteriuria since biofilm eventually forms on all of these devices. Despite the low percentage of people with bacteriuria who start showing symptoms, there is nevertheless a significant burden associated with these contamination due to the repeated use of indwelling urinary devices. Minimizing indwelling device usage and stopping the catheter as soon as medically possible are the two most crucial preventative measures for bacteriuria and infection when device use is required. Efforts to avoid catheter-acquired urinary infections must be implemented and monitored by infection control guidelines in healthcare institutions. These approaches include monitoring device use, the suitability of device justifications, and problems. Ultimately, technological advancements in device substances that inhibit colony generation will be necessary to avoid these infestations. There is still some way by which we can bring down the increased phenomenon of catheter-associated urinary tract contamination by maintaining hygiene while handling the catheter and patients and keeping the infected patients away or isolated from unaffected patients as a precaution. This article mainly focuses on an overview that helps with discussing prevention, risk factors, diagnosis, control and management of CAUTI.

Interactive Effects of Copper-Doped Urological Implants with Tissue in the Urinary Tract for the Inhibition of Cell Adhesion and Encrustation in the Animal Model Rat

The insertion of a ureteral stent provides acute care by restoring urine flow and alleviating urinary retention or dysfunction. The problems of encrustation, bacterial colonization and biofilm formation become increasingly important when ureteral stents are left in place for a longer period of time. One way to reduce encrustation and bacterial adherence is to modify the stent surface with a diamond-like carbon coating, in combination with copper doping. The biocompatibilities of the Elastollan^® base material and the a-C:H/Cu-mulitilayer coating were tested in synthetic urine. The copper content in bladder tissue was determined by atomic absorption spectroscopy and in blood and in urine by inductively coupled plasma mass spectrometry. Encrustations on the materials were analyzed by scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. A therapeutic window for copper ions of 0.5–1.0 mM was determined to kill bacteria without affecting human urothelial cells. In the rat animal model, it was found that copper release did not reach toxic concentrations in the affecting tissue of the urinary tract or in the blood. The encrustation behavior of the surfaces showed that the roughness of the amorphous carbon layer with the copper doping is probably the causal factor for the higher encrustation.

Staphylococcus aureus adhesion to the host

Staphylococcus aureus is a pathobiont capable of colonizing and infecting most tissues within the human body, resulting in a multitude of different clinical outcomes. Adhesion of S. aureus to the host is crucial for both host colonization and the establishment of infections. Underlying the pathogen's success is a complex and diverse arsenal of adhesins. In this review, we discuss the different classes of adhesins, including a consideration of the various adhesion sites throughout the body and the clinical outcomes of each infection type. The development of therapeutics targeting the S. aureus host-pathogen interaction is a relatively understudied area. Due to the increasing global threat of antimicrobial resistance, it is crucial that innovative and alternative approaches are considered. Neutralizing virulence factors, through the development of antivirulence agents, could reduce bacterial pathogenicity and the ever-increasing burden of S. aureus infections. This review provides insight into potentially efficacious adhesion-associated targets for the development of novel decolonizing and antivirulence strategies.

Phylogenetic Group B2 Expressed Significant Biofilm Formation among Drug Resistant Uropathogenic Escherichia coli

Biofilm is an important virulent marker attributed to the development of urinary tract infections (UTIs) by uropathogenic E. coli (UPEC). Drug-resistant and biofilm-producing UPEC are highly problematic causing catheter-associated or recurrent UTIs with significant morbidity and mortality. The aim of the current study was to investigate the prevalence of biofilm formation and phylogenetic groups in drug-resistant UPEC to predict their ability to cause disease. This prospective study was conducted at the Department of Microbiology, University of Karachi from January to June 2019. A total of 50 highly drug-resistant UPEC were selected for this study. UPEC isolates were screened to form biofilm by Congo-red agar (CRA) and microtiter plate (MTP) technique. The representative biofilm-producing isolates were analysed by scanning electron microscopy (SEM) monitoring. Phylogenetic analysis was done by PCR method based on two preserved genes; chuA, yjaA and TspE4-C2 DNA fragment. On CRA 34 (68%) UPEC were slime producers, while on MTP 20 (40%) were strong biofilm producers, 19 (38%) moderate and 11 (22%) were low to negligible biofilm producers. Molecular typing confirmed that phylogenetic group B2 was prevalent in drug resistant UPEC strains. Pathogenic strains belonged to phylogenetic group B2 and D were found to have greater biofilm forming ability as compare to non-pathogenic commensal strains that belonged to phylogenetic group A. Our results indicate that biofilm formation vary in drug resistant UPEC belonged to different phylogenetic groups. This study indicates possible link between in vitro biofilm formation and phylogenetic groups of UPEC, therefore this knowledge might be helpful to predict the pathogenic potential of UPEC and help design strategies for controlling UTIs.

Controlled Fragmentation of Urinary Stones as a Method of Preventing Inflammatory Infections in the Treatment of Urolithiasis (Experience in Successful Clinical Use)

The introduction of technologically advanced methods of lithotripsy into medical practice changes the nature of postoperative complications. Among them, the main complications are inflammatory infections. This largely determines the search for new, improved methods of stone fragmentation avoiding small stone fragments and dissemination of the pelvicalyceal system of the kidney with stone-associated infection. The authors have developed a method for controlled stone fragmentation using a continuous-wave diode laser with a hot-spot effect at the optical fiber end. The aim of the study was to evaluate the efficacy of controlled urinary stone fragmentation using a continuous-wave diode laser with a highly heated distal end of the optical fiber light guide as a method of preventing inflammatory infections in clinical practice.

Materials and Methods

We analyzed 1666 case histories of urolithiasis patients who underwent percutaneous nephrolithotripsy/ nephrolithoextraction and contact ureterolithotripsy/ureteroextraction, we also performed a prospective analysis of complications based on the Clavien-Dindo classification in 90 patients who underwent fine fragmentation of stones with various lithotripters: ultrasonic, pneumatic, and holmium laser. The method of controlled stone fragmentation by a diode laser with a hot-spot effect was tested on postoperative samples of 26 renal calculi. For the first time in clinical practice, this method was tested in the bladder cavity (n=10).

Results

In the percutaneous nephrolithotripsy group, postoperative infectious and inflammatory complications occurred in 34.1% of cases, in the percutaneous nephrolithoextraction group - in 24.6%, in the contact ureterolithotripsy group - in 7.8%, in the ureterolithoextraction group - in 2.5%. The analysis made it possible to identify factors promoting the development of infectious and inflammatory complications. For the first time in clinical practice, there were successfully performed ten operations of stone fragmentation using a continuous-wave diode laser with a hot-spot effect. Controlled coarse fragmentation of stones providing the possibility to reduce the number of infectious and inflammatory complications was performed in the bladder as a model for testing the method.

Conclusion

The method of laser-induced controlled coarse fragmentation of stones with a hot-spot effect, developed and tested in clinical practice, is promising for the prevention of infectious and inflammatory complications in patients with potentially infected stones since their fine fragmentation and, consequently, spread of stone-associated toxins and microflora within the urinary system is avoided.

Potential Probiotics Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 Co-Aggregate with Clinical Isolates of Proteus mirabilis and Prevent Biofilm Formation

A urinary tract infection (UTI) is a multi-factorial disease including cystitis, pyelonephritis, and pyelitis. After Escherichia coli, Proteus mirabilis is the most common UTI-associated opportunistic pathogen. Antibiotic resistance of bacteria and infection recurrence can be connected to biofilm formation by P. mirabilis. In this study, human and sheep isolates of P. mirabilis were investigated for antibiotic sensitivity using an antibiotic disk test. Co-aggregation of the tested potential probiotic bacilli, Bacillus amyloliquefaciens B-1895 and Bacillus subtilis KATMIRA1933, with the isolated pathogen was also evaluated. Then, the anti-biofilm activity of naturally derived metabolites, such as subtilin and subtilosin, in the bacilli-free supernatants was assessed against biofilms of P. mirabilis isolates. The isolated pathogens were sensitive to 30 μg of amikacin and 5 μg of ciprofloxacin but resistant to other tested antibiotics. After 24 h, auto-aggregation of B. amyloliquefaciens B-1895 was at 89.5% and higher than auto-aggregation of B. subtilis KATMIRA1933 (59.5%). B. amyloliquefaciens B-1895 strongly co-aggregated with P. mirabilis isolates from human UTIs. Cell-free supernatants of B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933 showed higher antimicrobial activity against biofilms of P. mirabilis isolated from humans as compared with biofilms of sheep isolates. According to our knowledge, this is the first report evaluating the anti-biofilm activity of probiotic spore-forming bacilli against clinical and animal UTI isolates of P. mirabilis. Further studies are recommended to investigate the anti-biofilm activity and the mode of action for the antimicrobial substances produced by these bacilli, subtilosin and subtilin.

Antibacterial activity of iron oxide, iron nitride, and tobramycin conjugated nanoparticles against Pseudomonas aeruginosa biofilms

BACKGROUND

Novel methods are necessary to reduce morbidity and mortality of patients suffering from infections with Pseudomonas aeruginosa. Being the most common infectious species of the Pseudomonas genus, P. aeruginosa is the primary Gram-negative etiology responsible for nosocomial infections. Due to the ubiquity and high adaptability of this species, an effective universal treatment method for P. aeruginosa infection still eludes investigators, despite the extensive research in this area.

RESULTS

We report bacterial inhibition by iron-oxide (nominally magnetite) nanoparticles (NPs) alone, having a mean hydrodynamic diameter of ~ 16 nm, as well as alginate-capped iron-oxide NPs. Alginate capping increased the average hydrodynamic diameter to ~ 230 nm. We also investigated alginate-capped iron-oxide NP-drug conjugates, with a practically unchanged hydrodynamic diameter of ~ 232 nm. Susceptibility and minimum inhibitory concentration (MIC) of the NPs, NP-tobramycin conjugates, and tobramycin alone were determined in the PAO1 bacterial colonies. Investigations into susceptibility using the disk diffusion method were done after 3 days of biofilm growth and after 60 days of growth. MIC of all compounds of interest was determined after 60-days of growth, to ensure thorough establishment of biofilm colonies.

CONCLUSIONS

Positive inhibition is reported for uncapped and alginate-capped iron-oxide NPs, and the corresponding MICs are presented. We report zero susceptibility to iron-oxide NPs capped with polyethylene glycol, suggesting that the capping agent plays a major role in enabling bactericidal ability in of the nanocomposite. Our findings suggest that the alginate-coated nanocomposites investigated in this study have the potential to overcome the bacterial biofilm barrier. Magnetic field application increases the action, likely via enhanced diffusion of the iron-oxide NPs and NP-drug conjugates through mucin and alginate barriers, which are characteristic of cystic-fibrosis respiratory infections. We demonstrate that iron-oxide NPs coated with alginate, as well as alginate-coated magnetite-tobramycin conjugates inhibit P. aeruginosa growth and biofilm formation in established colonies. We have also determined that susceptibility to tobramycin decreases for longer culture times. However, susceptibility to the iron-oxide NP compounds did not demonstrate any comparable decrease with increasing culture time. These findings imply that iron-oxide NPs are promising lower-cost alternatives to silver NPs in antibacterial coatings, solutions, and drugs, as well as other applications in which microbial abolition or infestation prevention is sought.

Prevention and management of urosepsis triggered by ureteroscopy

Urosepsis is a potentially life-threatening phenomenon that may occur after an ureteroscopic procedure. With the increasingly widespread adoption of ureteroscopy, there is a concern that the rates of urosepsis may increase. This review examines the current work being undertaken to minimize postprocedure infections both in the field of device development and in clinical care. Guidelines for the diagnosis and management of urosepsis will be discussed.

Bacterial colonization of penile prosthesis after its withdrawal due to mechanical failure

INTRODUCTION

Prosthetic surgery to treat erectile dysfunction has a risk of infection of up to 3%, but this risk can increase to 18% when the surgery involves replacement. This increased risk of infection is attributed to the bacterial colonization of the prosthesis during the initial surgery.

OBJECTIVE

To analyse the presence of germs in the prosthesis that is withdrawn due to mechanical failure (not infection), as well as the surgical results and its progression.

MATERIALS AND METHOD

A retrospective study was conducted of all replacements performed between 2013 and 2016 at a single centre. We analysed demographic data, prior type of prosthesis, surgical procedure, microbiological study and follow-up.

RESULTS

Of the 12 replacement procedures, a microbiological study of the extracted prosthesis was performed in a total of 10 cases. Of the 10 replacements, the cultures were positive in 5 cases (50%). Staphylococcus epidermidis was the most prevalent germ. All patients underwent a flushing procedure, and an antibiotic-coated prosthesis was implanted. We recorded no infections with the new implanted device after a mean follow-up of 27.33 months (SD 4.13; 95% CI 18.22-36.43).

CONCLUSION

In our study population, we observed a high rate of bacterial colonization of the prostheses that were replaced due to mechanical failure. When a flushing procedure was performed during the replacement surgery, there were no more infections than those reported in treatment-naive cases.

Microbial Biofilms in Urinary Tract Infections and Prostatitis: Etiology, Pathogenicity, and Combating strategies

Urinary tract infections (UTIs) are one of the most important causes of morbidity and health care spending affecting persons of all ages. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. UTIs associated with microbial biofilms developed on catheters account for a high percentage of all nosocomial infections and are the most common source of Gram-negative bacteremia in hospitalized patients. The purpose of this mini-review is to present the role of microbial biofilms in the etiology of female UTI and different male prostatitis syndromes, their consequences, as well as the challenges for therapy.

Impact of ureteral stenting in ureteroscopy

PURPOSE OF REVIEW

We review new therapies and biomaterials designed to reduce ureteral stent symptoms in patients undergoing ureteroscopy.

RECENT FINDINGS

Pharmacologically, alpha blockers and antimuscarinics have been shown to have a synergistic effect and be more effective than either medication alone in reducing stent-related symptoms. Prestenting patients prior to ureterosocpy has been shown to be beneficial for patients with renal stones, offering a better stone-free rate and reduced complications, but not for ureteral stones. Stenting after use of a ureteral access sheath reduced complications and unscheduled emergency visits. Nonsteroidal anti-inflammatories have been shown to prevent pain after stent removal. Surveys showed that patients preferred to remove their own stents via dangle strings at home or undergo cystoscopic removal in the operating room with some type of anesthesia. New materials such as gel-based or biodegradable ureteral stents are being developed to deal with stent-related pain, encrustation, and infection. Antirefluxing stents eliminate vesicoureteric reflux in patients during voiding and may reduce symptoms of back and flank pain. Ureteral stents are involved in many procedures in urology and particularly kidney stone treatments.

SUMMARY

Advances in materials and medications will help improve the patient experience for those who receive a ureteral stent.

Endoscopic and Pathologic Characterization of Papillary Architecture in Struvite Stone Formers

OBJECTIVE

To describe the endoscopic characteristics of renal papillae in struvite stone formers (SFs).

MATERIALS AND METHODS

From 2009 to 2014, patients undergoing percutaneous nephrolithotomy were prospectively enrolled in our study. Endoscopic analysis and biopsy of papillae were performed to demonstrate the presence and percentage surface area (SA) of Randall's plaque or ductal plug. Comparison with idiopathic calcium oxalate (CaOx) SF and non-SF controls was performed.

RESULTS

We identified 29 struvite SFs to compare with 90 idiopathic CaOx SFs and 17 controls. On endoscopic mapping, 28 struvite SFs (97%) demonstrated Randall's plaque and 9 (31%) had plugging. The average mean SA of Randall's plaque in struvite SF (1.5 ± 1.4%) was less than CaOx SFs (3.7 ± 4.3%, P  =  .0018) and similar to controls (1.7 ± 2.7%, P  =  .76). Average mean plug SA was similar between struvite SFs, CaOx SFs, and controls. On metabolic assessment, 83% of struvite SFs had at least one urine abnormality, with urinary uric acid and oxalate levels significantly higher among struvite SFs compared to controls (P  =  .002). Despite lack of active urinary tract infection, interstitial inflammation was more prevalent in struvite SFs compared to CaOx SFs (43.5% vs 7.3%, P  =  .0001).

CONCLUSIONS

Our findings suggest a limited role for Randall's plaque in struvite stone formation. Struvite SFs have less plaque formation than CaOx SFs, but demonstrate evidence of severe parenchymal inflammation compared to other SFs. The role of this prominent interstitial inflammation requires further study.

Importance of Biofilms in Urinary Tract Infections: New Therapeutic Approaches

Bacterial biofilms play an important role in urinary tract infections (UTIs), being responsible for persistence infections causing relapses and acute prostatitis. Bacterial forming biofilm are difficult to eradicate due to the antimicrobial resistant phenotype that this structure confers being combined therapy recommended for the treatment of biofilm-associated infections. However, the presence of persistent cells showing reduced metabolism that leads to higher levels of antimicrobial resistance makes the search for new therapeutic tools necessary. Here, a review of these new therapeutic approaches is provided including catheters coated with hydrogels or antibiotics, nanoparticles, iontophoresis, biofilm enzyme inhibitors, liposomes, bacterial interference, bacteriophages, quorum sensing inhibitors, low-energy surface acoustic waves, and antiadhesion agents. In conclusion, new antimicrobial drugs that inhibit bacterial virulence and biofilm formation are needed.

Evaluation of a novel gel-based ureteral stent with biofilm-resistant characteristics

PURPOSE

Current ureteral stents, while effective at maintaining a ureteral lumen, provide a substrate for bacterial growth. This propensity for biofilm formation may be a nidus for bacterial growth leading to infection and a reason for early removal of a stent before it is clinically indicated. A newly devised stent, composed of a highly hydrated, partially hydrolyzed polyacrylonitrile polymer, is believed to have bacterial resistant properties. The objective of this study is to evaluate the biofilm growth and bacterial resistant properties of this novel stent.

MATERIALS AND METHODS

Multiple 1 cm sections of the pAguaMedicina™ Pediatric Ureteral Stent (pAMS) (Q Urological, Natick, MA) and the conventional polymer stent (SS) (Boston Scientific, Natick, MA) were incubated for 3 days in the 3 different growth media. Afterward, J96 human pathogenic Escherichia coli was added. At 3, 6, 9, 12, and 15 days following bacterial inoculation, the stent segments were washed, sonicated, and analyzed for bacterial growth. Scanning electron microscopy (SEM) imaging was performed to assess biofilm formation.

RESULTS

pAMS demonstrated significant reductions (43-71 %) in bacterial counts when compared to standard stents in all conditions tested. SEM imaging demonstrated biofilm formation on both types of stents in all media, with a relative reduction in apparent cell debris and bacteria on the pAMS.

CONCLUSIONS

In this study, the gel-based stent shows a demonstrable reduction in bacterial counts and biofilm formation. The use of the pAMS may reduce the risk of infection associated with stent usage.

The assessment of Proteus mirabilis susceptibility to ceftazidime and ciprofloxacin and the impact of these antibiotics at subinhibitory concentrations on Proteus mirabilis biofilms

Rods of the Proteus genus are commonly isolated from patients, especially from the urinary tracts of the catheterised patients. The infections associated with biomaterials are crucial therapeutic obstacles, due to the bactericidal resistance of the biofilm. The aim of this study was to assess the susceptibility of P. mirabilis planktonic forms to ciprofloxacin and ceftazidime, the ability to form biofilm, and the impact of chosen sub-MIC concentrations of these antibiotics on biofilm at different stages of its formation. The research included 50 P. mirabilis strains isolated from wounds and the urinary tracts from patients of the University Hospital No. 1 in Bydgoszcz. The assessment of susceptibility to ciprofloxacin and ceftazidime was conducted using micromethods. The impact of sub-MIC concentrations of the chosen antibiotics on the biofilm was measured using the TTC method. The resistance to ciprofloxacin was confirmed for 20 strains (40.0%) while to ceftazidime for 32 (64.0%) of the tested P. mirabilis strains. All of the tested strains formed biofilm: 24.0% weakly, 26.0% moderately, and 50.0% strongly. It was determined that ciprofloxacin and ceftazidime caused eradication of the biofilm. Moreover, the connection between origin of the strains, biofilm maturity level, and resistance to antibiotics was proved.

Is biofilm formation related to the hypermutator phenotype in clinical Enterobacteriaceae isolates?

In bacteria, complex adaptive processes are involved during transition from the planktonic to the biofilm mode of growth, and mutator strains are more prone to producing biofilms. Enterobacteriaceae species were isolated from urinary tract infections (UTIs; 222 strains) and from bloodstream infections (BSIs; 213 strains). Relationship between the hypermutable phenotype and biofilm forming capacity was investigated in these clinical strains. Mutation frequencies were estimated by monitoring the capacity of each strain to generate mutations that conferred rifampicin resistance on supplemented medium. Initiation of biofilm formation was assayed by determining the ability of the cells to adhere to a 96-well polystyrene microtitre plate. UTI Enterobacteriaceae strains showed significantly higher biofilm-forming capacity: 63.1% (54.0% for E. coli strains) vs. 42.3% for BSI strains (47.7% for E. coli). Strains isolated from UTIs did not present higher mutation frequencies than those from BSIs: contrary to what has been widely described for P. aeruginosa strains, isolated from pulmonary samples in patients suffering from cystic fibrosis, no relationship was found between the hypermutator phenotype in Enterobacteriaceae and the ability to initiate a biofilm.

Enteric Gram-negative bacilli suppress Candida biofilms on Foley urinary catheters

Mixed Candida-bacterial biofilms in urinary catheters are common in hospitalized patients. (i) The aims of this study were to evaluate, quantitatively and qualitatively, the in vitro development of mono- and dual-species biofilms (MSBs and DSBs) of Candida albicans and two enteric gram-negative bacilli (EGNB; Pseudomonas aeruginosa or Escherichia coli) on Foley catheter (FC) discs, (ii) to determine the biofilm growth in tryptic soy broth or glucose supplemented artificial urine (AU) and (iii) to assess the inhibitory effects of EGNB and their lipopolysaccharides (LPS) on Candida biofilm growth. The growth of MSBs and DSBs on FC discs was monitored by cell counts and SEM. The metabolic activity of LPS-treated Candida biofilms was determined by the XTT reduction assay. Candida albicans and EGNB demonstrated significant inter- and intra-species differences in biofilm growth on FC discs (p < 0.01). Pseudomonas aeruginosa suppressed Candida albicans significantly (p < 0.001) in DSBs. Compared with MSBs, DSB of EGNB in glucose supplemented AU demonstrated robust growth. Escherichia coli and its LPS, significantly suppressed Candida biofilm growth, compared with Pseudomonas aeruginosa and its LPS (p < 0.001). Candida albicans and EGNB colonization in FC is significantly increased in AU with glucose, and variably modified by Escherichia coli, Pseudomonas aeruginosa and their corresponding LPS.

Coated implants and "no touch" surgical technique decreases risk of infection in inflatable penile prosthesis implantation to 0.46%

OBJECTIVE

To explore whether a "no touch" enhancement to the surgical technique of inflatable penile prosthesis (IPPs) implantaion will further decrease infection rates.

MATERIALS AND METHODS

A single surgeon performed 2347 IPPs between January 2002 and June 2011. Patients receiving each manufacturer's implants were stratified for age and diabetes. Since 2003, infection retardant-coated IPPs were implanted through the standardized penoscrotal approach. Since 2006, the "no touch" enhancement was added to the surgical procedure. Infection rates in the noncoated IPP, coated IPP with standard technique, and coated IPP implanted with "no touch" enhancement were calculated and subjected to statistical analysis. The two company's implants were scrutinized for their individual infection rates in each group.

RESULTS

Patients in all the groups were similar for age and diabetes. 132 noncoated implants had an infection rate of 5.3%. In the years 2003-2005, 704 coated devices had a statistically significant improvement in incidence of infection to 2%. In the years 2006-2010, the "no touch" technique enhanced the standard surgical procedure in 1511 patients. Only 7 infections were seen yielding an infection incidence of 0.46%. There was no difference in the two manufacturer's infection rates. Differentiation between virgin and revision operation displayed no bias in the infection rate.

CONCLUSION

Infection-retardant coatings lower the risk of infection from 5.3% to 2%. The "no touch" enhancement to the surgical procedure further decreases the rate of infection to 0.46%. Neither manufacturer showed statistical superiority in survival from revision for infection.

Recognition and prevention of healthcare-associated urinary tract infections in the intensive care unit

Urinary tract infection is the most common healthcare-associated infection in the intensive care unit and predominantly occurs in patients with indwelling urinary catheters. The predominant microorganisms causing catheter-associated urinary tract infection (CAUTI) in the intensive care unit are enteric Gram-negative bacilli, enterococci, Candida species, and Pseudomonas aeruginosa. Multidrug resistance is a significant problem in urinary pathogens. Duration of catheterization is the most important risk factor for development of CAUTI. Diagnosis, particularly in the intensive care unit setting, is very difficult, as asymptomatic bacteriuria may be difficult to differentiate from symptomatic CAUTI. In general, asymptomatic bacteriuria should not be treated, and treatment of CAUTI often requires removal of the catheter along with systemic antimicrobial therapy. General strategies for prevention of CAUTI apply to all healthcare-associated infections and include measures such as adherence to hand hygiene. Targeted strategies for prevention of CAUTI include limiting the use and duration of urinary catheterization, using aseptic technique for catheter insertion, and adhering to proper catheter care.

Staphylococcus epidermidis device-related infections: pathogenesis and clinical management

Staphylococcus epidermidis, the most frequently isolated coagulase-negative staphylococcus, is the leading cause of infection related to implanted medical devices (IMDs). This is directly related to its capability to establish multilayered, highly structured biofilms on artificial surfaces. At present, conventional systemic therapies using standard antimicrobial agents represent the main strategy to treat and prevent medical device-associated infections. However, device-related infections are notoriously difficult to treat and bacteria within biofilm communities on the surface of IMDs frequently outlive treatment, and removal of the medical device is often required for successful therapy. Importantly, major advances in this research area have been made, leading to a greater understanding of the complexities of biofilm formation of S. epidermidis and resulting in significant developments in the treatment and prevention of infections related to this member of the coagulase-negative group of staphylococci. This review will examine the pathogenesis of the clinically significant S. epidermidis and provide an overview of the conventional and emerging antibiofilm approaches in the management of medical device-associated infections related to this important nosocomial pathogen.

Presence of five conditioning film proteins are highly associated with early stent encrustation

PURPOSE

Ureteral stents are susceptible to biofilm formation and crystal deposition, especially in stone formers. To identify proteins responsible for this accumulation, we compared conditioning film proteomes obtained from human ureteral stents with and without encrustation.

MATERIALS AND METHODS

Twenty-seven Bard Inlay hydrophilic ureteral stents were removed after ureteroscopy. Stent encrustation was quantified by visual analog score 0 (none) to 4 (heavy) and further categorized as nonencrusted (scores 0 and 1; n = 22) or encrusted (scores 2, 3, and 4; n = 5). Stent conditioning film was sampled and digested with trypsin, and peptide tandem mass spectrometry data were acquired using liquid chromatography. After protein identification, unconditional exact tests were used to compare categorical variables versus encrustation outcome. Stone analysis and follow-up metabolic urine profiles were examined to identify additional risk factors for stent encrustation.

RESULTS

More than 300 unique proteins with >95% confidence were identified. Proteins alpha-1 anti-trypsin, Ig kappa, IgH G1, and histone H2b and H3a were found to be highly associated with stent encrustation (p < 0.05), while Tamm-Horsfall protein and histone H2a were found to have a marginal association (p < 0.1). Patients with early stent encrustation were more likely to have mixed stone analysis (p = 0.03) and low urinary volumes (p < 0.01).

CONCLUSION

Immunoglobulins and Tamm-Horsfall protein are common urinary proteins that appear to nonselectively bind early onto ureteral stent surfaces. Histones, nuclear DNA-condensing proteins, likely contribute to stent encrustation because of their unique net positive charge and may represent a potential clinical target for encrustation prevention.

Characteristics and clinical significance of bacterial colonization of ureteral double-J stents in children

OBJECTIVE

To determine the frequency, type of pathogen and clinical significance of bacterial colonization of double-J stents after pyeloplasty in children.

PATIENTS AND METHODS

The medical files of 82 consecutive children (22 girls, 60 boys) who underwent pyeloplasty at a tertiary pediatric medical center in 2000-2007 were reviewed. Additional inclusion criteria were sterile urine preoperatively and placement of an indwelling double-J stent during surgery. Intravenous gentamicin was administered prior to pyeloplasty and stent removal; cephalexin was administered postoperatively until discharge. Children with a postoperative urinary tract infection (UTI) received full-dose antimicrobial treatment followed by prophylaxis until stent removal.

RESULTS

Median patient age at surgery was 11 months (1 month-17.5 years). Forty-nine stents were inserted on the left side, 32 on the right, and one bilaterally. Cultures showed bacterial colonization in 58 cases (70.7%); 15 (25.8%) grew Staphylococcus (coagulase negative and positive). Eight children had febrile UTI postoperatively; in four the stent was colonized by Enterococci and in one by Proteus; three were sterile. There was no statistically significant association between positive stent culture and febrile UTI, patient age or sex, or stent laterality. The study was potentially limited by its observational design, small sample size, and the selective antibiotic treatment of patients with UTI which may have affected stent bacterial resistance.

CONCLUSION

Bacterial colonization is not uncommon in double-J stents retained for several weeks after pyeloplasty, but is usually not clinically significant. Enterococcus is the most frequent pathogen.

Uropathogen interaction with the surface of urological stents using different surface properties

PURPOSE

Ureteral stents commonly become infected or encrusted. Various coatings have been developed to decrease bacterial adherence. To our knowledge there has been no in vitro testing of coating with heparin to date. We determined the effects of heparin coating on bacterial adherence of common uropathogens and physical stent properties.

MATERIALS AND METHODS

Heparin coated Radiance ureteral stents (Cook) and noncoated Endo-Sof control stents were tested against triclosan eluting Triumph(R) stents and noneluting Polaris control stents for adherence of Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, Staphylococcus aureus and Pseudomonas aeruginosa for 7 days. Adherent bacteria were determined and biofilms were visualized using fluorescent dyes. Radial, tensile and coil strength of the Radiance and Polaris stents was compared to determine the effect of heparin coating on physical stent characteristics.

RESULTS

Heparin coating did not decrease bacterial adhesion compared to its control. E. coli adhesion was limited by all stents tested. The Polaris stent showed significantly greater resistance to bacterial adherence for Klebsiella, Pseudomonas and Enterococcus than the Endo-Sof and Radiance stents but was more susceptible to S. aureus adherence. The Triumph stent resisted all bacteria except Pseudomonas and Enterococcus. Mature biofilms were observed on all stents with lower viability on the Triumph stent. Radiance stents showed higher tensile and lower compression strength than its control.

CONCLUSIONS

Heparin coating does not decrease bacterial adherence to ureteral stents. Drug eluting antimicrobials have an inhibitory effect on bacterial adherence and the Polaris stent showed the least bacterial adherence of the nondrug eluting ureteral stents tested.

The pathogenesis of catheter-associated urinary tract infection

Catheter-associated urinary tract infection (CAUTI) remains one of the most common types of hospital-acquired infections. Further progress in the prevention of CAUTI requires a better understanding of its pathogenesis. Bacteria may enter the bladder through contamination of the tip during insertion with the flora of the distal urethra or from bacteria ascending the outside or the inside of the catheter. Residual urine in the bladder of catheterised patients increases the risk of bacteriuria. During the process of infection, bacteria need first to adhere to the epithelial cells of the urinary tract and/or the surface of the catheter. They will then develop into biofilms on the catheter surface and are resistant to the immune system and antibiotics. Catheters by themselves may cause immediate physical damage to the bladder epithelium; they may be toxic and also cause inflammation. Bacteria can also damage the epithelium and cause inflammation and the combination of both may be synergistic in producing symptoms in the patient. Most episodes of catheter-associated bacteriuria are asymptomatic but it is not known why some patients are symptomatic and others are not. Further research into the pathogenesis of CAUTI needs to be carried out. A suggestion for the prevention of CAUTI is the use of catheters with an additional eye-hole beneath the balloon to prevent residual urine in the bladder or to remove the tip and balloon altogether, with the additional benefit of having no tip to cause damage or inflammation to the bladder epithelium.

Role of bacterial biofilms in urinary tract infections

Bacterial urinary tract infections represent the most common type of nosocomial infection. In many cases, the ability of bacteria to both establish and maintain these infections is directly related to biofilm formation on indwelling devices or within the urinary tract itself. This chapter will focus on the role of biofilm formation in urinary tract infections with an emphasis on Gram-negative bacteria. The clinical implications of biofilm formation will be presented along with potential strategies for prevention. In addition, the role of specific pathogen-encoded functions in biofilm development will be discussed.

European and Asian guidelines on management and prevention of catheter-associated urinary tract infections

We surveyed the extensive literature regarding the development, therapy and prevention of catheter-associated urinary tract infections (UTIs). We systematically searched for meta-analyses of randomised controlled trials available in Medline giving preference to the Cochrane Central Register of Controlled Trials and also considered other relevant publications, rating them on the basis of their quality. The studies' recommendations, rated according to a modification of the US Department of Health and Human Services (1992), give a close-to-evidence-based guideline for all medical disciplines, with special emphasis on urology where catheter care is an important issue. The survey found that the urinary tract is the commonest source of nosocomial infection, particularly when the bladder is catheterised (IIa). Most catheter-associated UTIs are derived from the patient's own colonic flora (IIb) and the catheter predisposes to UTI in several ways. The most important risk factor for the development of catheter-associated bacteriuria is the duration of catheterisation (IIa). Most episodes of short-term catheter-associated bacteriuria are asymptomatic and are caused by a single organism (IIa). Further organisms tend to be acquired by patients catheterised for more than 30 days. The clinician should be aware of two priorities: the catheter system should remain closed and the duration of catheterisation should be minimal (A). While the catheter is in place, systemic antimicrobial treatment of asymptomatic catheter-associated bacteriuria is not recommended (A), except for some special cases. Routine urine culture in an asymptomatic catheterised patient is also not recommended (C) because treatment is in general not necessary. Antibiotic treatment is recommended only for symptomatic infection (B). Long-term antibiotic suppressive therapy is not effective (A). Antibiotic irrigation of the catheter and bladder is of no advantage (A). Routine urine cultures are not recommended if the catheter is draining properly (C). A minority of patients can be managed with the use of the non-return (flip) valve catheter, avoiding the closed drainage bag. Such patients may exchange the convenience of on-demand drainage with an increased risk of infection. Patients with urethral catheters in place for 10 years or more should be screened annually for bladder cancer (C). Clinicians should always consider alternatives to indwelling urethral catheters that are less prone to causing symptomatic infection. In appropriate patients, suprapubic catheters, condom drainage systems and intermittent catheterisation are each preferable to indwelling urethral catheterisation (B).

Pathophysiology and Management of Infectious Staghorn Calculi

The American Urological Association Nephrolithiasis Guidelines Panel recently conducted a critical meta-analysis of the existing literature to determine the optimal management for staghorn calculi. This article briefly discusses the pathophysiology of staghorn calculi and, based on the panel's recommendations, examines the alternative medical treatments (eg, chemolysis) and surgical treatments (eg, shock wave lithotripsy, open surgery, ureteroscopy, and percutaneous nephrolithotomy) available for staghorn patients. Considering the various modalities for staghorn disease, percutaneous nephrolithotomy should be the first-line treatment for most patients based on its superior efficacy and low morbidity.

In-vitro activity of triclosan-eluting ureteral stents against common bacterial uropathogens

BACKGROUND AND PURPOSE

Ureteral stents are commonly used in urology today, but the biofilms that form on them within hours of placement may harbor bacteria that can result in infection or encrustation. Triclosan is an antimicrobial commonly used in consumer and medical products that inhibits bacterial fatty-acid synthesis. The bactericidal and bacteriostatic effect of a triclosan-eluting ureteral stent was tested against clinical isolates of common bacterial uropathogens in an in-vitro setting.

MATERIALS AND METHODS

Triclosan eluted from a drug-loaded ureteral stent was suspended in artificial urine with bacterial pathogens (Escherichia coli C1214, Proteus mirabilis 296, Enterococcus faecalis 1131, Klebsiella pneumoniae 280, Staphylococcus aureus Newman, Pseudomonas aeruginosa AK1) to assess growth, virulence-promoter activity, and bacterial adherence to the stent. Generic stents were utilized as controls.

RESULTS

Triclosan inhibited the growth of E. faecalis, K. pneumoniae, S. aureus, and P. mirabilis in a dose-dependent manner. Pseudomonas aeruginosa demonstrated significant resistance. Lower concentrations of triclosan downregulated E. coli virulence-factor promoters of outer membrane protein X and p-fimbriae. Triclosan stents had significantly fewer adherent viable bacteria than control stents.

CONCLUSIONS

Triclosan-eluting ureteral stents inhibit the growth of common bacterial uropathogens and thus may reduce the incidence of urinary-tract infections and, potentially, encrustation. This drug-eluting stent provides both mechanical drainage of the upper urinary tract and local antibiosis.

Biofilm formation on clinically noninfected penile prostheses

PURPOSE

Biofilms are matrix enclosed bacterial populations that adhere to each other and/or to surfaces of implanted medical devices. Biofilm formation has consistently been demonstrated in association with infected penile prosthetic material. Clinically noninfected patients undergoing revision for mechanical malfunction have a surprisingly high rate of positive intraoperative cultures. After revision replacement prostheses have a higher rate of postoperative infection than first time implants. We characterized biofilm formation on penile prostheses in clinically noninfected patients undergoing revision surgery.

MATERIALS AND METHODS

Ten patients undergoing revision or removal of inflatable penile prosthetic devices due to mechanical malfunction were included. Specimens from the corporeal cylinders, scrotal pump and reservoir were analyzed. Bacterial biofilm coverage was detected and characterized using confocal scanning laser microscopy.

RESULTS

Bacterial biofilm formation associated with multiple microorganisms was demonstrated on 8 of 10 prostheses. Biofilms consisted of gram-positive rods, cocci and fungal elements.

CONCLUSIONS

The degree of biofilm formation on these prosthetic devices suggests that most patients have bacterial coverage on the implant. Host mechanisms to control infection may lead to a homeostatic balance that enables biofilms to exist on the surface of the prosthesis without generating clinical infection. A critical threshold of biofilm extent may exist beyond which clinical infection may occur. These results justify further evaluation of biofilms and penile prosthesis infections. Furthermore, the findings help to explain why strategies such as mini salvage procedures to eliminate subclinical biofilms may decrease the postoperative infection risk in patients undergoing repair or replacement of penile prostheses.

The hydrophilic-coated inflatable penile prosthesis: 1-year experience

INTRODUCTION

Penile prosthesis infections are a devastating complication for both patient and surgeon. Efforts to reduce the risk of infection from these elective procedures are a major focus of research and development by the major prosthesis companies. The Titan inflatable penile prosthesis (Mentor Corporation, Santa Barbara, CA) is coated with polyvinylpyrrolidone (PVP), a hydrophilic substance that reduces bacterial adherence and absorbs and elutes the antibiotics the device is immersed in intraoperatively. The Titan device was introduced to the American market in September 2002. This study reports the 1-year experience in the U.S. with the Titan and compares infection rates with the noncoated Alpha-1 IPP made by Mentor.

MATERIALS AND METHODS

Two thousand three hundred and fifty-seven Titan prostheses were implanted in the U.S. from September 2002 to August 2003, compared with the 482 noncoated Alpha-1 IPPs implanted over the same time period. Infection rates were compared, along with bacterial culture data. All data were collected from Mentor's internal database, as generated from the FDA's mandatory reporting of explanted medical devices, and available on the internet.

RESULTS

The infection rate for the coated Titan IPP was 1.06% (25/2,357). During the same time period, the infection rate for the Alpha-1 noncoated prosthesis was 2.07% (10/482). Staphylococcus species predominated in both groups (9/25 Titan, 6/10 Alpha-1).

CONCLUSIONS

At 1 year of follow-up, the data demonstrate that the hydrophilic coating on the Titan IPP confers a significant advantage in reducing the rate of infection over the noncoated device. Long-term follow-up on this first year database is needed before this innovation is accepted as the standard of care for prosthetic surgery. Nevertheless, the theoretical reduction in bacterial adhesion conferred by the hydrophilic PVP surface and the ability to choose which antibiotic the device is immersed in intraoperatively gives the implanting surgeon distinct advantages with this new product.

Increased biofilm formation in Escherichia coli isolated from acute prostatitis

Using crystal violet binding assay, we examined the potential for biofilm formation in 194, 76 and 107 isolates from urine of patients with uncomplicated acute cystitis, pyelonephritis and prostatitis, respectively. The prostatitis isolates showed significantly higher optical density (OD) values compared with cystitis and pyelonephritis isolates (OD(540): 0.82, 0.29 and 0.43, respectively, P<0.0001). Similarly, strains of serotypes O4 and O22, which were commonly isolated from prostatitis, exhibited significantly higher OD values than did other strains. Furthermore, when the 21 prostatitis isolates were examined for expression of curli fimbriae, eight of 12 strains with a high OD value, but only three of nine with a low OD value, expressed curli fimbriae (P=0.0195). These results suggest an association between acute bacterial prostatitis and biofilm formation.

Biofilm: its relevance in kidney disease

Biofilm/bioslime is a complex, dynamically interactive multicellular community protected within a heterogeneous exopolysaccharide matrix. Its formation results in the genesis or perpetuation of infection, enhancement of inflammation, and tissue damage or death. Industrial financial losses result from biofilm/bioslime formation; however, the consequences in the medical realm are equally devastating. The relation of biofilm to patients with chronic kidney disease is often covert and extends beyond the colonization of hemodialysis circuits and vascular accesses. Urinary tract device- and vascular access-related biofilms may also increase the burden of cardiovascular risk borne by chronic kidney disease patients, synergizing with the chronic inflammatory state already incurred by these individuals. Current anti-infective strategies are aimed at rapidly killing planktonic forms of microorganisms without specifically targeting the sessile forms that perpetuate their planktonic brethren. Future treatments of infections must ultimately target these reservoirs of infection aiming for their complete eradication. Presently, included among these novel weapons of microdestruction are molecular blockading techniques, electrical enhancement of anti-infectives, and bacterial interference. Nonetheless, the best approach against biofilm formation remains the prevention of microbial colonization, which can be largely by sterile handling of patient-related devices, the most well-established biofilm reservoirs.

Technology insight: Novel ureteral stent materials and designs

Ureteral stents are an important tool for aiding upper urinary tract drainage, but can cause significant patient morbidity. Common problems include stent-induced pain, hematuria, dysuria, infection, and encrustation. From a urologist's perspective, stents must be easy to maneuver in the urinary tract, radiopaque, and affordable. Since the development of the modern day stent in 1978, stents have evolved to include softer biomaterials that are more resistant to encrustation and infection. An ideal biomaterial is one that is not affected by its environment and does not elicit reactive changes in surrounding tissues. To date, the ideal biomaterial or stent does not exist. This review discusses developments that address the issues of infection, biofilm formation, encrustation, and patient comfort. Stent materials including polyurethane, silicone, biodegradable substances and new combination polymers are reviewed, in addition to novel stent coatings such as heparin, hydrogel, and silver nitrate. Ureteral stent technologies currently lag behind vascular stents, particularly drug-eluting stents, but new developments will continue to improve these essential urological tools.

The role of biofilm infection in urology

In the process of endourological development a great variety of foreign bodies have been invented besides urinary catheters on which biofilm can be formed. Bacteria in the biofilm are less sensible to antibiotics. An additional problem of medical biomaterials in the urinary tract environment is the development of encrustation and consecutive obstruction. In this review, we tried to sum up the conditions where biofilm formation has a great impact on the development or maintenance of urological infections and on treatment success. Modification of the biomaterial surface seems to be the most promising prevention strategy for bacterial biofilms. Easier methods for diagnosing and quantifying biofilm infection, to develop more specific antimicrobial agents and ideal device surfaces would surely help the fight against biofilm formation.

Complications of transvaginal silicone-coated polyester synthetic mesh sling

OBJECTIVES

To report a premarket multicenter trial to test the feasibility of a transvaginal silicone-coated polyester synthetic mesh sling in women with anatomic incontinence.

METHODS

Fifty-one patients in four centers underwent transvaginal placement of a silicone-coated polyester synthetic mesh sling (American Medical Systems) during an 8-month period. Of the 51 patients, 31 were part of a prospective institutional review board-approved feasibility trial in three centers funded by American Medical Systems (group 1) and 20 underwent implantation by a single surgeon and their data were retrospectively reviewed (group 2). The studies were done concomitantly, and all slings were fixed transvaginally with bone anchors. All patients in group 1 were followed up at 4 weeks, 6 months, and 1 year (as applicable) with repeat questionnaires, physical examinations, and pad tests.

RESULTS

In group 1, 20 patients completed 6 months of follow-up. Ten patients (32%) required a second surgical procedure at an average of 183 days (range 68 to 343) postoperatively. Eight patients (26%) had vaginal extrusion of the mesh, one (3%) required sling lysis, and one (3%) required sling removal because of infection. In group 2, 8 patients (40%) underwent sling removal for vaginal extrusion at a mean of 160 days (range 83 to 214).

CONCLUSIONS

Transvaginally placed silicone-coated mesh slings used for the treatment of urinary incontinence demonstrated an unacceptably high vaginal extrusion rate in this study. Once identified, this study was immediately terminated, and this product was not marketed for this application in the United States.