Safety and efficacy of a novel silver-impregnated urinary catheter system for preventing catheter-associated bacteriuria: a pilot randomized clinical trial

Materials-based incidence of urinary catheter associated urinary tract infections and the causative micro-organisms: systematic review and meta-analysis

BACKGROUND

Both long (> 30 days) and short-term (≤ 30 days) catheterisation has been associated with urinary tract infections (UTIs) due to the invasive nature of device insertion through the urethra. Catheter associated Urinary Tract Infections (CAUTIs) are common (prevalence of ~ 8.5%) infections which can be treated with antibiotics; however, CAUTIs are both expensive to treat and contributes to the antibiotic usage crisis. As catheters are unlikely be replaced for the management of patients' urination, ways of reducing CAUTIs are sought out, using the catheter device itself. The aim of this review is to assess the incidence of CAUTI and the causative micro-organisms when different urinary catheter devices have been used by humans, as reported in published research articles.

METHODS

A Systematic Literature Review was conducted in Ovid Medline, Web of Science and PubMed, to identify studies which investigated the incidence of UTI and the causative micro-organisms, in patients with different urinary catheter devices. The articles were selected based on a strict set of inclusion and exclusion criteria. The data regarding UTI incidence was extracted and calculated odds ratio were compared across studies and pooled when types of catheters were compared. CAUTI causative micro-organisms, if stated within the research pieces, were also gathered.

RESULTS

A total of 890 articles were identified, but only 26 unique articles met the inclusion/exclusion criteria for this review. Amongst the large cohort there were catheters of materials silicone, latex and PVC and catheter modifications of silver nanoparticles and nitrofurantoin antibiotics. The meta-analysis did not provide a clear choice towards a single catheter against another although silver-based catheters, and silver alloy, appeared to statistically reduce the OR of developing CAUTIs. At genus level the three commonest bacteria identified across the cohort were E. coli, Enterococcus spp. and Pseudomonas spp. whilst considering only at the genus level, with E. coli, Klebsiella pneumonia and Enterococcus faecalis most common at the species-specific level.

CONCLUSIONS

There does not appear to be a catheter type, which can significantly reduce the incidence of CAUTI's in patients requiring catheterisation. Ultimately, this warrants further research to identify and develop a catheter device material that will reduce the incidence for CAUTIs.

Single-center, double-blind, randomized, placebo-controlled pilot study of Canoxidin® for prevention of catheter encrustation in patients with indwelling catheters

INTRODUCTION AND OBJECTIVES

Long-term use of an indwelling catheter is associated with complications such as catheter encrustation and infection. Canoxidin® is a novel oral treatment that can potentially prevent catheter encrustation, as it contains a urine acidifier and a combination of two crystallization inhibitors. This study aimed to evaluate the effects of Canoxidin® on catheter encrustation in patients with indwelling Foley catheters.

PATIENTS AND METHODS

This was a single-center, double-blind, randomized, placebo-controlled study. Neuro-urology patients aged ≥18 years with an indwelling catheter (urethral or suprapubic) were randomized to treatment consisting of either Canoxidin® or placebo for one month. Foley catheters (two per patient, one before treatment and one after treatment) were removed for analysis of the presence and degree of encrustation.

RESULTS

A total of 40 patients were enrolled and randomized, 28 of whom had analyzable catheters (13 assigned to Canoxidin® and 15 assigned to placebo). The patients had a mean age of 51.8 years, and eight (28.6%) were female. Two patients (13.3%) in the placebo group and eight patients (61.5%) in the Canoxidin® group experienced an improvement (less encrustation). There was a significant association between Canoxidin® and improvement (odds ratio: 10.4, 95% confidence interval: 1.6 to 66.9, P = 0.016). No adverse effects attributable to the treatment were reported.

CONCLUSIONS

The overall rate of catheter encrustation was high among those with indwelling Foley catheters. One-month treatment with Canoxidin® reduced the formation of these encrustations, with an excellent short-term safety profile.

Medical Device-Associated Biofilm Infections and Multidrug-Resistant Pathogens

Medical devices such as venous catheters (VCs) and urinary catheters (UCs) are widely used in the hospital setting. However, the implantation of these devices is often accompanied by complications. About 60 to 70% of nosocomial infections (NIs) are linked to biofilms. The main complication is the ability of microorganisms to adhere to surfaces and form biofilms which protect them and help them to persist in the host. Indeed, by crossing the skin barrier, the insertion of VC inevitably allows skin flora or accidental environmental contaminants to access the underlying tissues and cause fatal complications like bloodstream infections (BSIs). In fact, 80,000 central venous catheters-BSIs (CVC-BSIs)-mainly occur in intensive care units (ICUs) with a death rate of 12 to 25%. Similarly, catheter-associated urinary tract infections (CA-UTIs) are the most commonlyhospital-acquired infections (HAIs) worldwide.These infections represent up to 40% of NIs.In this review, we present a summary of biofilm formation steps. We provide an overview of two main and important infections in clinical settings linked to medical devices, namely the catheter-asociated bloodstream infections (CA-BSIs) and catheter-associated urinary tract infections (CA-UTIs), and highlight also the most multidrug resistant bacteria implicated in these infections. Furthermore, we draw attention toseveral useful prevention strategies, and advanced antimicrobial and antifouling approaches developed to reduce bacterial colonization on catheter surfaces and the incidence of the catheter-related infections.

Purple urine bag syndrome: An unusual manifestation of urinary tract infection, our experience at a tertiary care center

Background

Purple urine bag syndrome (PUBS) is an unusual condition in which a purple discoloration of urine and bag occurs in people with urinary catheters. People with purple urine usually do not complain of any symptoms. The purple discoloration of the urine bag is often the only finding, frequently noted by caregivers.

Materials and methods

This prospective observational study was conducted at our tertiary care institute from June 2018 to May 2020. A total of 46 patients with PUBS were included in this study. The objective of our study was to record the prevalence of each predisposing factor and to correlate the pathological mechanism through which the PUBS is manifested.

Results

The mean age of PUBS patients was 67.4years and 67.4% were males. Most patients of PUBS (60.9%) had a urethral catheter, while there was percutaneous nephrostomy in 26.1% patients and 13% patients had a percutaneous suprapubic cystostomy catheter. Among the patients, 69.65% were bedridden or in an institutionalized situation, 73.9% were suffering from chronic constipation, 21.7% were associated with dementia, and 47.8% were cerebrovascular accidents with hemiparesis patients. In addition, 93.5% of patients presented with alkaline urine and 3 patients with acidic urine. The most common bacteria isolated in urine culture were E coli and Pseudomonas.

Conclusions

Urinary catheter associated urinary tract infection and PUBS is most commonly documented in females, but our study showed that it is more common in males. The appearance of a purple bag does not depend on the material and type of the catheter or the catheterization method. In addition, no correlation was found between the microorganisms isolated from the environment and patients' urine.

Choosing wisely initiative for reducing urine cultures for asymptomatic bacteriuria and catheter-associated asymptomatic bacteriuria in an 11-hospital safety net system

BACKGROUND

Treatment of asymptomatic bacteriuria (ASB) is common. Overtreatment of ASB leads to harm, including adverse effects from antibiotics, antibiotic resistance, and increased length of stay.

METHODS

This quality improvement initiative targeted inappropriate urine cultures (UC) across 11 hospitals and 70 ambulatory clinics in a safety-net setting. A mandatory prompt for appropriate indications for UC orders and a best practice advisory (BPA) for UC on patients with urinary catheters were created. UC ordering was compared preintervention (June 2020-October 2021) to postintervention (December 2021-August 2022). Variation in hospitals and clinics were assessed, as well as BPA responses by clinician type and specialty.

RESULTS

Inpatient UCs decreased 20.9% (p < .001), and outpatient UCs was unchanged (2.6% increase, nonsignificant). Inpatient UCs on patients with urinary catheters decreased 21.6% (p < .001). Temporal trends were also assessed. High variation was seen among hospitals and clinics. Low BPA acceptance rates were seen in internal medicine and family medicine clinicians. Attendings showed high acceptance to the BPA compared to other clinicians.

CONCLUSIONS

This initiative successfully decreased UCs in a large, safety-net system. Further study is needed in assessing variation among hospitals and clinics, as well as among clinician types and specialties.

Recent Advances in Antimicrobial Coatings and Material Modification Strategies for Preventing Urinary Catheter-Associated Complications

In recent years, we have witnessed prominent improvements in urinary catheter coatings to tackle the commonly occurring catheter-associated urinary tract infection (CAUTI) in catheterized patients. CAUTIs are claimed to be one of the most frequent nosocomial infections that can lead to various complications, from catheter encrustation to severe septicaemia and pyelonephritis. Besides general prevention hygienic strategies, antimicrobial-coated urinary catheters show great potential in the prevention of urinary catheter-associated complications. The aim of this review is to present and evaluate recent updates on the development of antimicrobial urinary catheters in the context of the aetiology of urinary malfunction. Subsequently, we shed some light on future perspectives of utilizing 3D printing and the surrounding regulatory directions.

Reduction of Catheter-Associated Urinary Tract Infections: A Multidisciplinary Approach to Driving Change

Despite the many advancements in infection prevention, catheter-associated urinary tract infections (CAUTI) continue to be problematic for many hospitals. The large urban teaching hospital featured in this article developed a team that consisted of a registered nurse quality Lean coach, bedside nurses from each inpatient nursing unit, physicians, an infection prevention specialist nurse, an education specialist nurse, and members of the quality department to study this matter. The team focused on understanding current practice related to the use and duration of indwelling urinary catheters. It was discovered that while some indwelling urinary catheters were justified, others could have been avoided altogether or removed earlier. Multifaceted measures were instituted at this hospital to decrease indwelling urinary catheter days and reduce CAUTI rates. The team's journey to successfully decreasing indwelling urinary catheter days by 19.79% and CAUTI rates by 38% is highlighted.

Assessment of persistent antimicrobial and anti-biofilm activity of p-HEMA hydrogel loaded with rifampicin and cefixime

Catheter-associated urinary tract infections (CAUTIs) are nosocomial infections causing more than one million hospital cases annually. The progress of CAUTIs leads to severe health complications. Infections result in blockage of the medical device due to biofilm formation, which necessitates the replacement of the device. The objective of this study is to improve urological biomaterials to minimize microbial growth and reduce the incidence of CAUTIs. Challenges from mixed biofilm are crucial and need to be addressed in the development of new coating materials. Herein, an investigation highlighted the reduction of mixed biofilm overgrowth and attachment tendency on poly-2-hydroxyethyl methacrylate (p-HEMA) surface by loading the hydrogel with rifampicin (RIF), cefixime trihydrate (CFX), and combined ratios of RIF and CFX. Mixed biofilm-formation ability in (3:1) RIF: CFX-loading p-HEMA (F6) surface showed best tendency to resist form biofilm. Persistent antimicrobial activity increased in p-HEMA loaded with combined ratios of RIF and CFX surface compared to p-HEMA alone, antimicrobial activity lasted for 8 days. All fabricated films exhibited %cell viability higher than 75% on HEK 293 cells. The addition of RIF and CFX may improve the duration of urological device employment before replacement.

Bioengineered phytomolecules-capped silver nanoparticles using Carissa carandas leaf extract to embed on to urinary catheter to combat UTI pathogens

Rising incidents of urinary tract infections (UTIs) among catheterized patients is a noteworthy problem in clinic due to their colonization of uropathogens on abiotic surfaces. Herein, we have examined the surface modification of urinary catheter by embedding with eco-friendly synthesized phytomolecules-capped silver nanoparticles (AgNPs) to prevent the invasion and colonization of uropathogens. The preliminary confirmation of AgNPs production in the reaction mixture was witnessed by the colour change and surface resonance plasmon (SRP) band at 410nm by UV–visible spectroscopy. The morphology, size, crystalline nature, and elemental composition of attained AgNPs were further confirmed by the transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD) technique, Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The functional groups of AgNPs with stabilization/capped phytochemicals were detected by Fourier-transform infrared spectroscopy (FTIR). Further, antibiofilm activity of synthesized AgNPs against biofilm producers such as Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were determined by viability assays and micrographically. AgNPs coated and coating-free catheters performed to treat with bacterial pathogen to analyze the mat formation and disruption of biofilm formation. Synergistic effect of AgNPs with antibiotic reveals that it can enhance the activity of antibiotics, AgNPs coated catheter revealed that, it has potential antimicrobial activity and antibiofilm activity. In summary, C. carandas leaf extract mediated synthesized AgNPs will open a new avenue and a promising template to embed on urinary catheter to control clinical pathogens.

Role of noble metal-coated catheters for short-term urinary catheterization of adults: a meta-analysis

OBJECTIVE

To evaluate the efficacy of noble-metal coated catheters in reducing catheter-associated urinary tract infections (CAUTI) in adult patients requiring short term catheterization.

METHODS

An electronic literature search of PubMed, BioMed Central, Embase, Scopus, CENTRAL (Cochrane Central Register of Controlled Trials) and Google scholar was carried out from inception to 10th October 2019. Any prospective study or randomized controlled trial (RCT) on adult patients comparing noble-metal coated urinary catheters with any standard catheter and evaluating the incidence of CAUTI or bacteriuria was included.

RESULTS

A total of 13 studies were included in the systematic review. 12 were RCTs and one was a prospective cross-over trial. Catheters employed in the study group were grouped into two sub-groups: Silver alloy coated or Noble metal alloy-coated (Gold, Silver, and Palladium) catheters. Bacteriuria was the most commonly studied outcome variable across trials. Meta-analysis indicated that silver alloy-coated catheters (RR 0.63, 95%CI 0.44-0.90, P = 0.01; I2 = 72%) and noble metal alloy catheters (RR 0.58, 95%CI 0.41-0.81, P = 0.001; I2 = 0%) significantly reduce the risk of bacteriuria. Sub-group analysis based on the duration of catheterization demonstrated that silver alloy catheters reduce the risk of bacteriuria with >1week of catheterization (RR 0.46, 95%CI 0.26-0.81, P = 0.007; I2 = 63%). Symptomatic CAUTI was evaluated only in four studies with variable results. The quality of the included studies was not high.

CONCLUSIONS

Our review indicates that bacteriuria may be reduced with the use of noble metal-coated catheters during short-term catheterization of adults, however, the quality of evidence is not high. It is not clear if these catheters reduce the risk of symptomatic CAUTI. Further homogenous RCTs are needed to provide clarity.

Urinary Catheter Coating Modifications: The Race against Catheter-Associated Infections

Urinary catheters are common medical devices, whose main function is to drain the bladder. Although they improve patients’ quality of life, catheter placement predisposes the patient to develop a catheter-associated urinary tract infection (CAUTI). The catheter is used by pathogens as a platform for colonization and biofilm formation, leading to bacteriuria and increasing the risk of developing secondary bloodstream infections. In an effort to prevent microbial colonization, several catheter modifications have been made ranging from introduction of antimicrobial compounds to antifouling coatings. In this review, we discuss the effectiveness of different coatings in preventing catheter colonization in vitro and in vivo, the challenges in fighting CAUTIs, and novel approaches targeting host–catheter–microbe interactions.

Value of surgical pilot and feasibility study protocols

BACKGROUND

RCTs in surgery are challenging owing to well established methodological issues. Well designed pilot and feasibility studies (PFS) may help overcome such issues to inform successful main trial design and conduct. This study aimed to analyse protocols of UK-funded studies to explore current use of PFS in surgery and identify areas for practice improvement.

METHODS

PFS of surgical interventions funded by UK National Institute for Health Research programmes from 2005 to 2015 were identified, and original study protocols and associated publications sourced. Data extracted included study design characteristics, reasons for performing the work including perceived uncertainties around conducting a definitive main trial, and whether the studies had been published.

RESULTS

Thirty-five surgical studies were identified, of which 29 were randomized, and over half (15 of 29) included additional methodological components (such as qualitative work examining recruitment, and participant surveys studying current interventions). Most studies focused on uncertainties around recruitment (32 of 35), with far fewer tackling uncertainties specific to surgery, such as intervention stability, implementation or delivery (10 of 35). Only half (19 of 35) had made their results available publicly, to date.

CONCLUSION

The full potential of pretrial work to inform and optimize definitive surgical studies is not being realized.

Local drug delivery in the urinary tract: current challenges and opportunities

Drug delivery is an important consideration in disease treatment. There are many opportunities for novel methods and technologies to hold promising roles in overcoming traditional obstacles. Delivery systems functionalised to boast synergistic antimicrobial effects, specific targeting, and enhanced bioavailability allow for improved therapeutic potential and better patient outcomes. Many of these delivery modalities find clinical practicality in the field of urology, specifically in the treatment of urinary tract infections (UTIs) and offer advantages over conventional methods. The aim of this review article is to discuss the current modalities of treatment for UTIs and the recent technological advancements for optimising drug delivery. We focus on challenges that persist in drug delivery during UTIs including barriers to antimicrobial penetration, drug resistance, biofilm formation and specific targeting limitations. With a discussion on how emerging methods combat these concerns, we present an overview of potential therapies with special emphasis on nanoparticle-based applications.

American Society for Enhanced Recovery (ASER) and Perioperative Quality Initiative (POQI) joint consensus statement on prevention of postoperative infection within an enhanced recovery pathway for elective colorectal surgery

BACKGROUND

Colorectal surgery (CRS) patients are an at-risk population who are particularly vulnerable to postoperative infectious complications. Infectious complications range from minor infections including simple cystitis and superficial wound infections to life-threatening situations such as lobar pneumonia or anastomotic leak with fecal peritonitis. Within an enhanced recovery pathway (ERP), there are multiple approaches that can be used to reduce the risk of postoperative infections.

METHODS

With input from a multidisciplinary, international group of experts and through a focused (non-systematic) review of the literature, and use of a modified Delphi method, we achieved consensus surrounding the topic of prevention of postoperative infection in the perioperative period for CRS patients.

DISCUSSION

As a part of the first Perioperative Quality Initiative (POQI-1) workgroup meeting, we sought to develop a consensus statement describing a comprehensive, yet practical, approach for reducing postoperative infections, specifically for CRS within an ERP. Surgical site infection (SSI) is the most common postoperative infection. To reduce SSI, we recommend routine use of a combined isosmotic mechanical bowel preparation with oral antibiotics before elective CRS and that infection prevention strategies (also called bundles) be routinely implemented as part of colorectal ERPs. We recommend against routine use of abdominal drains. We also give consensus guidelines for reducing pneumonia, urinary tract infection, and central line-associated bloodstream infection (CLABSI).

Scientific Opinion on the update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA

EFSA is requested to assess the safety of a broad range of biological agents in the context of notification for market authorisation as sources of food and feed additives, food enzymes and plant protection products. The qualified presumption of safety (QPS) assessment was developed to provide a harmonised generic pre-assessment to support safety risk assessments performed by EFSA's scientific Panels. The safety of unambiguously defined biological agents (at the highest taxonomic unit appropriate for the purpose for which an application is intended), and the completeness of the body of knowledge are assessed. Identified safety concerns for a taxonomic unit are, where possible and reasonable in number, reflected as 'qualifications' in connection with a recommendation for a QPS status. The list of QPS recommended biological agents was reviewed and updated in the current opinion and therefore becomes the valid list. The 2016 update reviews previously assessed microorganisms including bacteria, yeasts and viruses used for plant protection purposes following an Extensive Literature Search strategy. The taxonomic units related to the new notifications received since the 2013 QPS opinion, were periodically evaluated for a QPS status and the results published as Statements of the BIOHAZ Panel. Carnobacterium divergens, Lactobacillus diolivorans, Microbacterium imperiale, Pasteuria nishizawae, Pediococcus parvulus, Bacillus flexus, Bacillus smithii, Xanthomonas campestris and Candida cylindracea were recommended for the QPS list. All taxonomic units previously recommended for the 2013 QPS list had their status reconfirmed as well their qualifications with the exception of Pasteuria nishizawae for which the qualification was removed. The exclusion of filamentous fungi and enterococci from the QPS evaluations was reconsidered but monitoring will be maintained and the status will be re-evaluated in the next QPS Opinion update. Evaluation of bacteriophages should remain as a case-by-case procedure and should not be considered for QPS status.

A review of the recent advances in antimicrobial coatings for urinary catheters

More than 75% of hospital-acquired or nosocomial urinary tract infections are initiated by urinary catheters, which are used during the treatment of 15-25% of hospitalized patients. Among other purposes, urinary catheters are primarily used for draining urine after surgeries and for urinary incontinence. During catheter-associated urinary tract infections, bacteria travel up to the bladder and cause infection. A major cause of catheter-associated urinary tract infection is attributed to the use of non-ideal materials in the fabrication of urinary catheters. Such materials allow for the colonization of microorganisms, leading to bacteriuria and infection, depending on the severity of symptoms. The ideal urinary catheter is made out of materials that are biocompatible, antimicrobial, and antifouling. Although an abundance of research has been conducted over the last forty-five years on the subject, the ideal biomaterial, especially for long-term catheterization of more than a month, has yet to be developed. The aim of this review is to highlight the recent advances (over the past 10years) in developing antimicrobial materials for urinary catheters and to outline future requirements and prospects that guide catheter materials selection and design.

STATEMENT OF SIGNIFICANCE

This review article intends to provide an expansive insight into the various antimicrobial agents currently being researched for urinary catheter coatings. According to CDC, approximately 75% of urinary tract infections are caused by urinary catheters and 15-25% of hospitalized patients undergo catheterization. In addition to these alarming statistics, the increasing cost and health related complications associated with catheter associated UTIs make the research for antimicrobial urinary catheter coatings even more pertinent. This review provides a comprehensive summary of the history, the latest progress in development of the coatings and a brief conjecture on what the future entails for each of the antimicrobial agents discussed.

Influence of selected inorganic counter-ions on the structure and antimicrobial properties of silver(i) complexes with imidazole-containing ligands

Newly synthesized silver(i) complexes with 4(5)-(hydroxymethyl)imidazole and selected counter-ions show significant activity against Gram-positive bacteria, especially the one containing the trifluoroacetate counter-ion.

Antimicrobial activity and cytocompatibility of silver nanoparticles coated catheters via a biomimetic surface functionalization strategy

Catheter-related bloodstream infections are a significant problem in the clinic and may result in a serious infection. Here, we developed a facile and green procedure for buildup of silver nanoparticles (AgNPs) on the central venous catheters (CVCs) surface. Inspired by mussel adhesive proteins, dopamine was used to form a thin polydopamine layer and induce AgNPs formation without additional reductants or stabilizers. The chemical and physicochemical properties of AgNPs coated CVCs were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and water contact angle. The Staphylococcus aureus culture experiment was used to study the antibacterial properties. The cytocompatibility was assessed by water soluble tetrazolium salts (WST-1) assay, fluorescence staining, and scanning electron microscopy analysis. The results indicated that the CVCs surface was successfully coated with compact AgNPs. AgNPs were significantly well separated and spherical with a size of 30–50 nm. The density of AgNPs could be modulated by the concentration of silver nitrate solution. The antibacterial activity was dependent on the AgNPs dose. The high dose of AgNPs showed excellent antibacterial activity while associated with increased cytotoxicity. The appropriate density of AgNPs coated CVCs could exhibit improved biocompatibility and maintained evident sterilization effect. It is promising to design mussel-inspired silver releasing CVCs with both significant antimicrobial efficacy and appropriate biological safety.