Materials for urinary catheters: a review of their history and development in the UK

Finite element analysis of the interaction between high-compliant balloon catheters and non-cylindrical vessel structures: towards tactile sensing balloon catheters

Aiming for sensing balloon catheters which are able to provide intraoperative information of the vessel stiffness and shape, the present study uses finite element analysis (FEA) to evaluate the interaction between high-compliant elastomer balloon catheters with the inner wall of a non-cylindrical-shaped lumen structure. The contact simulations are based on 3D models with varying balloon thicknesses and varying tissue geometries to analyse the resulting balloon and tissue deformation as well as the inflation pressure dependent contact area. The wrinkled tissue structure is modelled by utilizing a two-layer fibre-based Holzapfel-Gasser-Ogden constitutive model and the model parameters are adapted based on available biomechanical data for human urethral vessel samples. The balloon catheter structure is implemented as a high-compliant hyper-elastic silicone material (based on polydimethylsiloxane (PDMS)) with a varying catheter wall thickness between 0.5 and 2.5 µm. Two control parameters are introduced to describe the balloon shape adaption in reaction to a wrinkled vessel wall during the inflation process. Basic semi-quantitative relations are revealed depending on the evolving balloon deformation and contact surface. Based on these relations some general design guidelines for balloon-based sensor catheters are presented. The results of the conducted in-silico study reveal some general interdependencies with respect to the compliance ratio between balloon and tissue and also in respect of the tissue aspect ratio. Further they support the proposed concept of high-compliant balloon catheters equipped for tactile sensing as diagnosis approach in urology and angioplasty.

Emerging evidence-based innovative approaches to control catheter-associated urinary tract infection: a review

Healthcare settings have dramatically advanced the latest medical devices, such as urinary catheters (UC) for infection, prevention, and control (IPC). The continuous or intermittent flow of a warm and conducive (urine) medium in the medical device, the urinary catheter, promotes the formation of biofilms and encrustations, thereby leading to the incidence of CAUTI. Additionally, the absence of an innate immune host response in and around the lumen of the catheter reduces microbial phagocytosis and drug action. Hence, the review comprehensively overviews the challenges posed by CAUTI and associated risks in patients' morbidity and mortality. Also, detailed, up-to-date information on the various strategies that blended/tailored the surface properties of UC to have anti-fouling, biocidal, and anti-adhesive properties to provide an outlook on how they can be better managed with futuristic solutions.

Understanding the properties of intermittent catheters to inform future development

Despite the extensive use of intermittent catheters (ICs) in healthcare, various issues persist for long-term IC users, such as pain, discomfort, infection, and tissue damage, including strictures, scarring and micro-abrasions. A lubricous IC surface is considered necessary to reduce patient pain and trauma, and therefore is a primary focus of IC development to improve patient comfort. While an important consideration, other factors should be routinely investigated to inform future IC development. An array of in vitro tests should be employed to assess IC's lubricity, biocompatibility and the risk of urinary tract infection development associated with their use. Herein, we highlight the importance of current in vitro characterisation techniques, the demand for optimisation and an unmet need to develop a universal 'toolkit' to assess IC properties.

Fabrication of antibacterial polydopamine-carboxymethyl cellulose-Ag nanoparticle hydrogel coating for urinary catheters

Urinary tract infections caused by catheter insertion are prevalent in hospital clinics, which can induce serious complications such as bacteriuria and sepsis, and even lead to patient death. The disposable catheters currently used in clinical practice suffer from poor biocompatibility and high infection rate. In this paper, we developed a polydopamine (PDA)-carboxymethylcellulose (CMC)-Ag nanoparticles (AgNPs) coating with both good antibacterial and anti-adhesion properties to bacteria on the surfaces of a disposable medical latex catheter by a simple dipping method. The antibacterial efficiency of the coated catheters against Gram-negative E. coli and Gram-positive S. aureus bacteria was evaluated with both inhibition zone tests and fluorescence microscopy. Compared with the untreated catheter, the PDA-CMC-AgNPs coated catheters showed both good antibacterial and anti-adhesion properties to bacteria, which inhibited the adhesion of live bacteria and dead bacteria by 99.0% and 86.6%, respectively. This novel PDA-CMC-AgNPs composite hydrogel coating has great potential in applications in catheters and other biomedical devices to reduce infections.

Preparation, Characterization, and Staphylococcus aureus Biofilm Elimination Effect of Baicalein-Loaded β-Cyclodextrin-Grafted Chitosan Nanoparticles

BACKGROUND AND PURPOSE

Infections caused by Staphylococcus aureus (S. aureus) colonization in medical implants are resistant to antibiotics due to the formation of bacterial biofilm internal. Baicalein (BA) has been confirmed as an inhibitor of bacterial biofilm with less pronounced effects owing to its poor solubility and absorption. Studies have found that β-cyclodextrin-grafted chitosan (CD-CS) can improve drug efficiency as a drug carrier. Therefore, this research aims to prepare BA-loaded CD-CS nanoparticles (CD-CS-BA-NPs) for S. aureus biofilm elimination enhancement.

METHODS

CD-CS-BA-NPs were prepared via the ultrasonic method. The NPs were characterized using the X-ray diffraction (XRD), Thermo gravimetric analyzer (TGA), Transmission electron microscopy (TEM) and Malvern Instrument. The minimum inhibitory concentration (MIC) of the NPs were investigated. The biofilm models in vivo and in vitro were constructed to assess the S. aureus biofilm elimination ability of the NPs. The Confocal laser method (CLSM) and the Live/Dead kit were employed to explore the mechanism of the NPs in promoting biofilm elimination.

RESULTS

CD-CS-BA-NPs have an average particle size of 424.5 ± 5.16 nm, a PDI of 0.2 ± 0.02, and a Zeta potential of 46.13 ± 1.62 mV. TEM images revealed that the NPs were spherical with uniform distribution. XRD and TGA analysis verified the formation and the thermal stability of the NPs. The NPs with a MIC of 12.5 ug/mL exhibited a better elimination effect on S. aureus biofilm both in vivo and in vitro. The mechanism study demonstrated that the NPs may permeate into the biofilm more easily, thereby improving the biofilm elimination effect of BA.

CONCLUSION

CD-CS-BA-NPs were successfully prepared with enhanced elimination of S. aureus biofilm, which may serve as a reference for future development of anti-biofilm agents.

Structure-Property Relationship Based on the Amino Acid Composition of Recombinant Spider Silk Proteins for Potential Biomedical Applications

Improving biomaterials by engineering application-specific and adjustable properties is of increasing interest. Most of the commonly available materials fulfill the mechanical and physical requirements of relevant biomedical applications, but they lack biological functionality, including biocompatibility and prevention of microbial infestation. Thus, research has focused on customizable, application-specific, and modifiable surface coatings to cope with the limitations of existing biomaterials. In the case of adjustable degradation and configurable interaction with body fluids and cells, these coatings enlarge the applicability of the underlying biomaterials. Silks are interesting coating materials, e.g., for implants, since they exhibit excellent biocompatibility and mechanical properties. Herein, we present putative implant coatings made of five engineered recombinant spider silk proteins derived from the European garden spider Araneus diadematus fibroins (ADF), differing in amino acid sequence and charge. We analyzed the influence of the underlying amino acid composition on wetting behavior, blood compatibility, biodegradability, serum protein adsorption, and cell adhesion. The outcome of the comparison indicates that spider silk coatings can be engineered for explicit biomedical applications.

Retardation of Bacterial Biofilm Formation by Coating Urinary Catheters with Metal Nanoparticle-Stabilized Polymers

Urinary catheter infections remain an issue for many patients and can complicate their health status, especially for individuals who require long-term catheterization. Catheters can be colonized by biofilm-forming bacteria resistant to the administered antibiotics. Therefore, this study aimed to investigate the efficacy of silver nanoparticles (AgNPs) stabilized with different polymeric materials generated via a one-step simple coating technique for their ability to inhibit biofilm formation on urinary catheters. AgNPs were prepared and characterized to confirm their formation and determine their size, charge, morphology, and physical stability. Screening of the antimicrobial activity of nanoparticle formulations and determining minimal inhibitory concentration (MIC) and their cytotoxicity against PC3 cells were performed. Moreover, the antibiofilm activity and efficacy of the AgNPs coated on the urinary catheters under static and flowing conditions were examined against a clinical isolate of Escherichia coli. The results showed that the investigated polymers could form physically stable AgNPs, especially those prepared using polyvinyl pyrrolidone (PVP) and ethyl cellulose (EC). Preliminary screening and MIC determinations suggested that the AgNPs-EC and AgNPs-PVP had superior antibacterial effects against E. coli. AgNPs-EC and AgNPs-PVP inhibited biofilm formation to 58.2% and 50.8% compared with AgNPs-PEG, silver nitrate solution and control samples. In addition, coating urinary catheters with AgNPs-EC and AgNPs-PVP at concentrations lower than the determined IC50 values significantly (p < 0.05; t-test) inhibited bacterial biofilm formation compared with noncoated catheters under both static and static and flowing conditions using two different types of commercial Foley urinary catheters. The data obtained in this study provide evidence that AgNP-coated EC and PVP could be useful as potential antibacterial and antibiofilm catheter coating agents to prevent the development of urinary tract infections caused by E. coli.

Antibacterial Designs for Implantable Medical Devices: Evolutions and Challenges

The uses of implantable medical devices are safer and more common since sterilization methods and techniques were established a century ago; however, device-associated infections (DAIs) are still frequent and becoming a leading complication as the number of medical device implantations keeps increasing. This urges the world to develop instructive prevention and treatment strategies for DAIs, boosting the studies on the design of antibacterial surfaces. Every year, studies associated with DAIs yield thousands of publications, which here are categorized into four groups, i.e., antibacterial surfaces with long-term efficacy, cell-selective capability, tailored responsiveness, and immune-instructive actions. These innovations are promising in advancing the solution to DAIs; whereas most of these are normally quite preliminary “proof of concept” studies lacking exact clinical scopes. To help identify the flaws of our current antibacterial designs, clinical features of DAIs are highlighted. These include unpredictable onset, site-specific incidence, and possibly involving multiple and resistant pathogenic strains. The key point we delivered is antibacterial designs should meet the specific requirements of the primary functions defined by the “intended use” of an implantable medical device. This review intends to help comprehend the complex relationship between the device, pathogens, and the host, and figure out future directions for improving the quality of antibacterial designs and promoting clinical translations.

Potent, Broad-Spectrum Antimicrobial Effects of S-Nitroso-N-acetylpenicillamine-Impregnated Nitric Oxide-Releasing Latex Urinary Catheters

Although numerous prevention and intervention techniques have been developed to counteract catheter-associated urinary tract infections (CAUTIs), urinary catheters remain one of the most common sources of hospital-acquired infections. Nitric oxide (NO), a gaseous free radical responsible for regulating many physiological functions in the body, has gained immense popularity due to its potent, broad-spectrum antimicrobial activity, which is capable of combating medical device-associated infections. In this work, a straightforward solvent-swelling method was used to load the NO donor S-nitroso-N-acetyl-penicillamine (SNAP) into commercial latex catheters (SNAP-UCs) for the first time. The effects of swelling catheters with different concentrations of SNAP solutions (25-125 mg/mL SNAP in tetrahydrofuran (THF)) were studied by measuring the NO release kinetics, SNAP loading, and SNAP leaching. SNAP-UCs impregnated with a 50 mg/mL SNAP-THF solution were found to maximize the amount of SNAP loaded into the latex (0.115 ± 0.009 mg SNAP/mg catheter) and showed physiological levels of NO release (>2 × 10^-10 mol min^-1 cm^-2) over 7 days and minimal SNAP leaching (<2%). SNAP-UCs showed impressive in vitro contact-based and diffusible antimicrobial efficacy against three CAUTI-associated pathogens, reducing the viability of adhered and planktonic Escherichia coli, Proteus mirabilis, and Staphylococcus aureus by ∼98.0 to 99.1% (adhered) and 86.3-96.3% (planktonic) compared to control latex catheters. In vitro cytotoxicity against 3T3 mouse fibroblasts using a CCK-8 assay showed that SNAP-UCs were noncytotoxic (>90% viability). In summary, SNAP-UCs show stable, noncytotoxic NO release characteristics capable of potent, broad-spectrum antimicrobial activity, demonstrating great potential for reducing the devastating effects associated with CAUTIs.

Modular 3D-Printed Peg Biofilm Device for Flexible Setup of Surface-Related Biofilm Studies

Medical device-related biofilms are a major cause of hospital-acquired infections, especially chronic infections. Numerous diverse models to study surface-associated biofilms have been developed; however, their usability varies. Often, a simple method is desired without sacrificing throughput and biological relevance. Here, we present an in-house developed 3D-printed device (FlexiPeg) for biofilm growth, conceptually similar to the Calgary Biofilm device but aimed at increasing ease of use and versatility. Our device is modular with the lid and pegs as separate units, enabling flexible assembly with up- or down-scaling depending on the aims of the study. It also allows easy handling of individual pegs, especially when disruption of biofilm populations is needed for downstream analysis. The pegs can be printed in, or coated with, different materials to create surfaces relevant to the study of interest. We experimentally validated the use of the device by exploring the biofilms formed by clinical strains of Escherichia coli and Klebsiella pneumoniae, commonly associated with device-related infections. The biofilms were characterized by viable cell counts, biomass staining, and scanning electron microscopy (SEM) imaging. We evaluated the effects of different additive manufacturing technologies, 3D printing resins, and coatings with, for example, silicone, to mimic a medical device surface. The biofilms formed on our custom-made pegs could be clearly distinguished based on species or strain across all performed assays, and they corresponded well with observations made in other models and clinical settings, for example, on urinary catheters. Overall, our biofilm device is a robust, easy-to-use, and relevant assay, suitable for a wide range of applications in surface-associated biofilm studies, including materials testing, screening for biofilm formation capacity, and antibiotic susceptibility testing.

Using Lactobacilli to Fight Escherichia coli and Staphylococcus aureus Biofilms on Urinary Tract Devices

The low efficacy of conventional treatments and the interest in finding natural-based approaches to counteract biofilm development on urinary tract devices have promoted the research on probiotics. This work evaluated the ability of two probiotic strains, Lactobacillus plantarum and Lactobacillus rhamnosus, in displacing pre-formed biofilms of Escherichia coli and Staphylococcus aureus from medical-grade silicone. Single-species biofilms of 24 h were placed in contact with each probiotic suspension for 6 h and 24 h, and the reductions in biofilm cell culturability and total biomass were monitored by counting colony-forming units and crystal violet assay, respectively. Both probiotics significantly reduced the culturability of E. coli and S. aureus biofilms, mainly after 24 h of exposure, with reduction percentages of 70% and 77% for L. plantarum and 76% and 63% for L. rhamnosus, respectively. Additionally, the amount of E. coli biofilm determined by CV staining was maintained approximately constant after 6 h of probiotic contact and significantly reduced up to 67% after 24 h. For S. aureus, only L. rhamnosus caused a significant effect on biofilm amount after 6 h of treatment. Hence, this study demonstrated the potential of lactobacilli to control the development of pre-established uropathogenic biofilms.

Effect of Lactobacillus plantarum Biofilms on the Adhesion of Escherichia coli to Urinary Tract Devices

Novel technologies to prevent biofilm formation on urinary tract devices (UTDs) are continually being developed, with the ultimate purpose of reducing the incidence of urinary infections. Probiotics have been described as having the ability to displace adhering uropathogens and inhibit microbial adhesion to UTD materials. This work aimed to evaluate the effect of pre-established Lactobacillus plantarum biofilms on the adhesion of Escherichia coli to medical-grade silicone. The optimal growth conditions of lactobacilli biofilms on silicone were first assessed in 12-well plates. Then, biofilms of L. plantarum were placed in contact with E. coli suspensions for up to 24 h under quasi-static conditions. Biofilm monitoring was performed by determining the number of culturable cells and by confocal laser scanning microscopy (CLSM). Results showed significant reductions of 76%, 77% and 99% in E. coli culturability after exposure to L. plantarum biofilms for 3, 6 and 12 h, respectively, corroborating the CLSM analysis. The interactions between microbial cell surfaces and the silicone surface with and without L. plantarum biofilms were also characterized using contact angle measurements, where E. coli was shown to be thermodynamically less prone to adhere to L. plantarum biofilms than to silicone. Thus, this study suggests the use of probiotic cells as potential antibiofilm agents for urinary tract applications.

Long-lasting hydrophilic surface generated on poly(dimethyl siloxane) with photoreactive zwitterionic polymers

Poly(dimethylsiloxane) (PDMS) is known as one of the most established polymers for making elastomers. Therefore, it is commonly used for the fabrication of biomedical devices. Many PDMS surface modification processes have been proposed recently to increase PDMS reliability in medical fields. However, the modified surface's long-term stability is still limited. Hydrophobic recovery of PDMS is widely recognized as a factor that reduces the efficacy of PDMS surface modification. The photoreactive zwitterionic polymer effectively suppresses the hydrophobic recovery of PDMS, according to the current analysis. The photoreactive zwitterionic monomer, 2-[2-(Methacryloyloxy)ethyldimethylanmmonium] ethyl benzophenoxy phosphate (MBPP) was polymerized by conventional radical polymerization and coated on O₂-plasma-treated PDMS specimens. The specimens were immersed in an aqueous solution of 2-methacryloyloxyethyl phosphorylcholine (MPC) and exposed under ultraviolet (UV) radiation for 3 h. Instead, of poly(MBPP) (PMBPP), benzophenone (BP) was also used as a conventional photoinitiator. The time-dependent change in the wettability and elemental composition of the specimen surface was monitored for nine weeks after photo-grafting of poly[2-methacryloyloxyethyl phosphorylcholine (MPC)] (PMPC). The advancing and receding contact angles (θ_A/θ_R) of the pristine PDMS specimen were 112°/71° and significantly decreased immediately after the grafting of PMPC regardless of types of photoinitiator. However, the hydrophobicity of the surface gradually recovered, and θ_A was changed from 12° to 81° for nine weeks of storage under air atmosphere when BP was used as a photoinitiator for graft polymerization of MPC. However, surface hydrophilicity (θ_A ≅ 20°) of the surface grafted with PMPC with PMBPP as an initiator was effectively preserved for nine weeks. This surface also showed excellent lubricity and non-fouling properties regardless of the storage periods. Therefore, zwitterionic photoreactive polymer, PMBPP, is then used as a macrophotoinitiator for the surface modification of PDMS.

Impact of DMPEI on Biofilm Adhesion on Latex Urinary Catheter

BACKGROUND

Microorganisms can migrate from the external environment to the patient's organism through the insertion of catheters. Despite being indispensable medical device, the catheter surface can be colonized by microorganisms and become a starting point for biofilm formation. Therefore, new technologies are being developed in order to modify surfaces to prevent the adhesion and survival of microorganisms. Patents with the use of DMPEI have been filed.

OBJECTIVE

In the present work, we coated latex catheter surfaces with 2 mg mL-1 DMPEI in different solvents, evaluated the wettability of the surface and the anti- biofilm activity of the coated catheter against Escherichia coli, Staphylococcus aureus, and Candida albicans.

METHODS

We coated the inner and outer catheter surfaces with 2 mg mL-1 of DMPEI solubilized in butanol, dimethylformamide, and cyclohexanone and the surfaces were analyzed visually. Contact angle measurement allowed the analysis of the wettability of the surfaces. The CFU mL-1 count evaluated E. coli, S. aureus, and C. albicans adhesion onto the control and treated surfaces.

RESULTS

The contact angle decreased from 50.48º to 46.93º on the inner surface and from 55.83º to 50.91º on the outer surface of latex catheters coated with DMPEI. The catheter coated with DMPEI showed anti-biofilm activity of 83%, 88%, and 93% on the inner surface and 100%, 92%, and 86% on the outer surface for E. coli, S. aureus, and C. albicans, respectively.

CONCLUSION

Latex catheter coated with DMPEI efficiently impaired the biofilm formation both on the outer and inner surfaces, showing a potential antimicrobial activity along with a high anti-biofilm activity for medical devices.

Antibacterial composite coatings of MgB2 powders embedded in PVP matrix

Three commercial powders of MgB₂ were tested in vitro by MTS and LDH cytotoxicity tests on the HS27 dermal cell line. Depending on powders, the toxicity concentrations were established in the range of 8.3–33.2 µg/ml. The powder with the lowest toxicity limit was embedded into polyvinylpyrrolidone (PVP), a biocompatible and biodegradable polymer, for two different concentrations. The self-replenishing MgB₂-PVP composite materials were coated on substrate materials (plastic foil of the reservoir and silicon tubes) composing a commercial urinary catheter. The influence of the PVP-reference and MgB₂-PVP novel coatings on the bacterial growth of Staphylococcus aureus ATCC 25923, Enterococcus faecium DMS 13590, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, in planktonic and biofilm state was assessed in vitro at 6, 24, and 48 h of incubation time. The MgB₂-PVP coatings are efficient both against planktonic microbes and microbial biofilms. Results open promising applications for the use of MgB₂ in the design of anti-infective strategies for different biomedical devices and systems.

Marine Microbial-Derived Antibiotics and Biosurfactants as Potential New Agents against Catheter-Associated Urinary Tract Infections

Catheter-associated urinary tract infections (CAUTIs) are among the leading nosocomial infections in the world and have led to the extensive study of various strategies to prevent infection. However, despite an abundance of anti-infection materials having been studied over the last forty-five years, only a few types have come into clinical use, providing an insignificant reduction in CAUTIs. In recent decades, marine resources have emerged as an unexplored area of opportunity offering huge potential in discovering novel bioactive materials to combat human diseases. Some of these materials, such as antimicrobial compounds and biosurfactants synthesized by marine microorganisms, exhibit potent antimicrobial, antiadhesive and antibiofilm activity against a broad spectrum of uropathogens (including multidrug-resistant pathogens) that could be potentially used in urinary catheters to eradicate CAUTIs. This paper summarizes information on the most relevant materials that have been obtained from marine-derived microorganisms over the last decade and discusses their potential as new agents against CAUTIs, providing a prospective proposal for researchers.

Mechanism of Adhesion of Natural Polymer Coatings to Chemically Modified Siloxane Polymer

Surface coatings play an important role in improving the performance of biomedical implants. Polydimethylsiloxane (PDMS) is a commonly used material for biomedical implants, and surface-coated PDMS implants frequently face problems such as delamination or cracking of the coating. In this work, we have measured the performance of nano-coatings of the biocompatible protein polymer silk fibroin (SF) on pristine as well as modified PDMS surfaces. The PDMS surfaces have been modified using oxygen plasma treatment and 3-amino-propyl-triethoxy-silane (APTES) treatment. Although these techniques of PDMS modification have been known, their effects on adhesion of SF nano-coatings have not been studied. Interestingly, testing of the coated samples using a bulk technique such as tensile and bending deformation showed that the SF nano-coating exhibits improved crack resistance when the PDMS surface has been modified using APTES treatment as compared to an oxygen plasma treatment. These results were validated at the microscopic and mesoscopic length scales through nano-scratch and nano-indentation measurements. Further, we developed a unique method using modified atomic force microscopy to measure the adhesive energy between treated PDMS surfaces and SF molecules. These measurements indicated that the adhesive strength of PDMS-APTES-SF is 10 times more compared to PDMS-O₂-SF due to the higher number of molecular linkages formed in this nanoscale contact. This lower number of molecular linkages in the PDMS-O₂ indicates that only fewer numbers of surface hydroxyl groups interact with the SF protein through secondary interactions such as hydrogen bonding. On the other hand, a larger number of amine groups present on PDMS-APTES surface hydrogen bond with the polar amino acids present on the silk fibroin protein chain, resulting in better adhesion. Thus, APTES modification to the PDMS substrate results in improved adhesion of nano-coating to the substrate and enhances the delamination and crack resistance of the nano-coatings.

A scope at antifouling strategies to prevent catheter-associated infections

The use of invasive medical devices is becoming more common nowadays, with catheters representing one of the most used medical devices. However, there is a risk of infection associated with the use of these devices, since they are made of materials that are prone to bacterial adhesion with biofilm formation, often requiring catheter removal as the only therapeutic option. Catheter-related urinary tract infections (CAUTIs) and central line-associated bloodstream infections (CLABSIs) are among the most common causes of healthcare-associated infections (HAIs) worldwide while endotracheal intubation is responsible for ventilator-associated pneumonia (VAP). Therefore, to avoid the use of biocides due to the potential risk of bacterial resistance development, antifouling strategies aiming at the prevention of bacterial adherence and colonization of catheter surfaces represent important alternative measures. This review is focused on the main strategies that are able to modify the physical or chemical properties of biomaterials, leading to the creation of antiadhesive surfaces. The most promising approaches include coating the surfaces with hydrophilic polymers, such as poly(ethylene glycol) (PEG), poly(acrylamide) and poly(acrylates), betaine-based zwitterionic polymers and amphiphilic polymers or the use of bulk-modified poly(urethanes). Natural polysaccharides and its modifications with heparin, have also been used to improve hemocompatibility. Recently developed bioinspired techniques yielding very promising results in the prevention of bacterial adhesion and colonization of surfaces include slippery liquid-infused porous surfaces (SLIPS) based on the superhydrophilic rim of the pitcher plant and the Sharklet topography inspired by the shark skin, which are potential candidates as surface-modifying approaches for biomedical devices. Concerning the potential application of most of these strategies in catheters, more in vivo studies and clinical trials are needed to assure their efficacy and safety for possible future use.

Surface analysis of ureteral stent before and after implantation in the bodies of child patients

The aim of this work was to determine which part of a double-J ureteral stent (DJ stents) showed the highest tendency to crystal, calculi, and biofilm deposition after ureterorenoscopic-lithotripsy procedure (URS-L) to treat calcium oxalate stones. Additionally, the mechanical strength and the stiffness of DJ stents were evaluated before and after exposure to urine. Obtained results indicated that the proximal (renal pelvis) and distal (urinary bladder) part is the most susceptible for post-URS-L fragments and urea salt deposition. Both, the outer and inner surfaces of the DJ ureteral stents were completely covered even after 7 days of implantation. Encrustation of DJ stents during a 31-day period results in reducing the Young’s modulus by 27–30%, which confirms the loss of DJ stent elasticity and increased probability of cracks or interruption. Performed analysis pointed to the need to use an antibacterial coating in the above-mentioned part of the ureteral stent to prolong its usage time and to prevent urinary tract infection.

Attenuation of Proteus mirabilis colonization and swarming motility on indwelling urinary catheter by antibiofilm impregnation: An in vitro study

Proteus mirabilis is one of the important etiologic agents of urinary tract infections (UTI), which complicates the long-term urinary catheterization process in clinical settings. Owing to its crystalline biofilm forming ability and flagellar motility, elimination of P. mirabilis from urinary system becomes very difficult. Thus, the present study is focused to prepare antibiofilm-impregnated Silicone Foley Catheter (SFC) to prevent P. mirabilis instigated UTIs. Through solvent swelling method, the antibiofilm compounds such as linalool (LIN) and 2-hydroxy-4-methoxy benzaldehyde (HMB) were successfully infused into SFCs. Surface topography was studied using AFM analysis, which unveiled the unmodified surface roughness of normal and antibiofilm-impregnated SFCs. In addition, UV-spectrometric and FT-IR analyses revealed good impregnation efficacy and prolonged stability of antibiofilm compounds. Further, in vitro biofilm biomass quantification assay exhibited a maximum of 87 % and 84 % crystalline biofilm inhibition in LIN (350 μg/cm³) and HMB (120 μg/cm³) impregnated SFCs, respectively against P. mirabilis in artificial urine medium. Also, the LIN & HMB-impregnated SFCs demonstrated long-term crystalline biofilm inhibitory activity for more than 30 days, which is ascribed to the sustained release of the compounds. Furthermore, the results of swarming motility analysis revealed the efficacy of antibiofilm-impregnated catheters to mitigate the migration of pathogens over them. Thus, antibiofilm-impregnated catheter is proposed to act as a suitable strategy for reducing P. mirabilis infections and associated complications in long-term urinary catheter users.

The Effect of Intravesical Diluted Bupivacaine on Catheter-Related Bladder Discomfort in Young and Middle-Aged Male Patients During Postanaesthetic Recovery

Objective

Catheter-related bladder discomfort (CRBD) that manifests as agitation and bladder hyperactivity is a common problem in young male patients. Local anaesthetics are typically recommended for this problem. Hence, this study was conducted to determine the effect of intravesical diluted bupivacaine on CRBD in young male patients during postanaesthetic recovery.

Methods

This double-blinded randomised clinical trial included 68 consecutive patients, aged 20–60 years, who underwent urinary catheterisation during surgery and anaesthesia at a university hospital during 2017–2018. Patients were randomly assigned to receive either 50 ml of intravesical diluted (0.2%) bupivacaine (n=37) or normal saline (n=31). The incidence and severity of CRBD were then evaluated in PACU and compared between the two groups.

Results

In this study, 16.2% of patients in the bupivacaine group and 83.9% in the saline group had discomfort at arrival in the recovery room, exhibiting a significant intergroup difference (p=0.0001). Moreover, after 15–20 min, the incidence of CRBD was 16.2% and 90.3% in the bupivacaine and normal saline groups, respectively, which again demonstrated a significant statistical difference (p=0.0001). In addition, the severity of CRBD was lower in the bupivacaine group, during both periods (p=0.005). The saline group reported significantly higher use of pethidine and midazolam (p=0.005).

Conclusion

It may be concluded that intravesical diluted bupivacaine can significantly decrease the incidence and severity of CRBD in young male patients during recovery from anaesthesia. Therefore, the use of this method is highly recommended.

Immobilized Acylase PvdQ Reduces Pseudomonas aeruginosa Biofilm Formation on PDMS Silicone

The bacterial biofilm plays a key role in nosocomial infections, especially those related to medical devices in sustained contact with patients. The active dispersion of bacterial cells out of biofilms acts as a reservoir for infectious diseases. The formation of such biofilms is a highly complex process, which is coordinated by many regulatory mechanisms of the pathogen including quorum sensing (QS). Many bacteria coordinate the expression of key virulence factors dependent on their population density through QS. The inhibition of this system is called quorum quenching (QQ). Thus, preventing the development of biofilms is considered a promising approach to prevent the development of hard to treat infections. Enzymatic QQ is the concept of interfering with the QS system of bacteria outside the cell. PvdQ is an acylase with an N-terminal nucleophile (Ntn-hydrolase) that is a part of the pyoverdine gene cluster (pvd). It is able to cleave irreversibly the amide bond of long chain N-acyl homoserine lactones (AHL) rendering them inactive. Long chain AHLs are the main signaling molecule in the QS system of the gram-negative pathogen Pseudomonas aeruginosa PA01, which is known for surface-associated biofilms on indwelling catheters and is also the cause of catheter-associated urinary tract infections. Furthermore, PA01 is a well characterized pathogen with respect to QS as well as QQ. In this study, we immobilized the acylase PvdQ on polydimethylsiloxane silicone (PDMS), creating a surface with quorum quenching properties. The goal is to control infections by minimizing the colonization of indwelling medical devices such as urinary catheters or intravascular catheters. The enzyme activity was confirmed by testing the degradation of the main auto-inducer that mediates QS in P. aeruginosa. In this article we report for the first time a successful immobilization of the quorum quenching acylase PvdQ on PDMS silicone. We could show that immobilized PvdQ retained its activity after the coating procedure and showed a 6-fold reduction of the auto-inducer 3-oxo-C12 in a biosensor setup. Further we report significant reduction of a P. aeruginosa PA01 biofilm on a coated PDMS surface compared to the same untreated material.

The Use of Copper as an Antimicrobial Agent in Health Care, Including Obstetrics and Gynecology

Health care-associated infections (HAIs) are a global problem associated with significant morbidity and mortality. Controlling the spread of antimicrobial-resistant bacteria is a major public health challenge, and antimicrobial resistance has become one of the most important global problems in current times. The antimicrobial effect of copper has been known for centuries, and ongoing research is being conducted on the use of copper-coated hard and soft surfaces for reduction of microbial contamination and, subsequently, reduction of HAIs. This review provides an overview of the historical and current evidence of the antimicrobial and wound-healing properties of copper and explores its possible utility in obstetrics and gynecology.

Design and evaluation of the crimping of a hooked self-expandable caval valve stent for the treatment of tricuspid regurgitation

To design a hooked self-expandable caval valve stent and determine the best crimping scenario for its percutaneous implantation in the Superior and Inferior Vena Cava (SVC & IVC) for the treatment of tricuspid regurgitation (TR). A hooked, Nitinol based stent design was modeled using SOLIDWORKS and finite element analysis (FEA) was carried out using ABAQUS. The Nitinol material used in this study was modeled in ABAQUS as superelastic-plastic. Two cases were simulated. In case A, the stent model was crimped to 18 F by compressing the stent main body and then: (i) bending both the proximal and distal hooks; (ii) straightening the proximal hooks and bending the distal hooks. In case B, the stent model was crimped to 18 F by: (i) bending the proximal and distal hooks and then compressing the stent main body; (ii) straightening the proximal hooks and bending the distal hooks and then compressing the stent main body. The maximum strain after crimping was used to evaluate the best crimping scenario. Hook straightening produced strains of 10.7% and 10.96% as opposed to 12.6% and 13.0% produced by hook bending. From comparison of results of both cases simulated, it was found that straightening the hooks gave lower strain and thus was the best crimping procedure. The analysis performed in this paper may help understand the critical issue of crimpability of the new stent design. The best crimping scenario can be found based on finite element modeling and simulation. Identifying the best crimping way will also help the design team to optimize the delivery system that will eventually be used to deploy this caval valve stent.

Active agents, biomaterials, and technologies to improve biolubrication and strengthen soft tissues

Normal functioning of articulating tissues is required for many physiological processes occurring across length scales from the molecular to whole organism. Lubricating biopolymers are present natively on tissue surfaces at various sites of biological articulation, including eyelid, mouth, and synovial joints. The range of operating conditions at these disparate interfaces yields a variety of tribological mechanisms through which compressive and shear forces are dissipated to protect tissues from material wear and fatigue. This review focuses on recent advances in active agents and biomaterials for therapeutic augmentation of friction, lubrication, and wear in disease and injured states. Various small-molecule, biological, and gene delivery therapies are described, as are tribosupplementation with naturally-occurring and synthetic biolubricants and polymer reinforcements. While reintroduction of a diseased tissue's native lubricant received significant attention in the past, recent discoveries and pre-clinical research are capitalizing on concurrent advances in the molecular sciences and bioengineering fields, with an understanding of the underlying tissue structure and physiology, to afford a desired, and potentially patient-specific, tissue mechanical response for restoration of normal function. Small and large molecule drugs targeting recently elucidated pathways as well as synthetic and hybrid natural/synthetic biomaterials for restoring a desired tissue mechanical response are being investigated for treatment of, for example, keratoconjunctivitis sicca, xeroderma, and osteoarthritis.

Fouling-Resistant Hydrogels Prepared by the Swelling-Assisted Infusion and Polymerization of Dopamine

Biofilm-associated infections stemming from medical devices are increasingly challenging to treat due to the spread of antibiotic resistance. In this study, we present a simple strategy that significantly enhances the antifouling performance of covalently crosslinked poly(ethylene glycol) (PEG) and physically crosslinked agar hydrogels by incorporation of the fouling-resistant polymer zwitterion, poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC). Dopamine polymerization was initiated during swelling of the hydrogels, which provided dopamine and pMPC an osmotic driving force into the hydrogel interior. Both PEG and agar hydrogels were synthesized over a broad range of storage moduli (1.7,1300 kPa), which remained statistically equivalent after being functionalized with pMPC and polydopamine (PDA). When challenged with fibrinogen, a model blood-clotting protein, the pMPC/PDA-functionalized PEG and agar hydrogels displayed a >90% reduction in protein adsorption compared to hydrogel controls. Further, greater than an order-of-magnitude reduction in Escherichia coli and Staphylococcus aureus adherence was observed. This study demonstrates a versatile materials platform to enhance the fouling resistance of hydrogels through a pMPC/PDA incorporation strategy that is independent of the chemical composition and network structure of the original hydrogel.

A case of neglected silicone tube in lacrimal duct for 20 years

Purpose

To report a case of prolonged placement of a lacrimal silicone tube for 20 years, with evaluation of the lacrimal duct using lacrimal micro-endoscopy and inspection of deformation of the lacrimal tube.

Observations

This study involved a case of dacryocystitis in which a silicone tube had been placed in the patient 20-years previous and that was treated conservatively. Although granulation tissue formation due to dacryocystitis in the lacrimal duct was observed under lacrimal micro-endoscopy, subjective and objective resolution of symptoms, including granulated tissue formation, was achieved after removal of the silicone tube and conservative medical treatment. Follow-up examinations performed over a 12-month period post treatment revealed no recurrence of epiphora or anatomical obstruction. Inspection of the lacrimal tube using the tension test revealed minimal changes in the tube in situ for 20 years.

Conclusions and Importance

The findings in this case suggest both the lacrimal system and the silicone tube are tolerant to prolonged intubation, as long as the tube had been placed properly with careful observation. Our findings may encourage physicians to consider prolonged intubation for select cases of nasolacrimal duct obstruction.

A Critical Review on Metallic Glasses as Structural Materials for Cardiovascular Stent Applications

Functional and mechanical properties of novel biomaterials must be carefully evaluated to guarantee long-term biocompatibility and structural integrity of implantable medical devices. Owing to the combination of metallic bonding and amorphous structure, metallic glasses (MGs) exhibit extraordinary properties superior to conventional crystalline metallic alloys, placing them at the frontier of biomaterials research. MGs have potential to improve corrosion resistance, biocompatibility, strength, and longevity of biomedical implants, and hence are promising materials for cardiovascular stent applications. Nevertheless, while functional properties and biocompatibility of MGs have been widely investigated and validated, a solid understanding of their mechanical performance during different stages in stent applications is still scarce. In this review, we provide a brief, yet comprehensive account on the general aspects of MGs regarding their formation, processing, structure, mechanical, and chemical properties. More specifically, we focus on the additive manufacturing (AM) of MGs, their outstanding high strength and resilience, and their fatigue properties. The interconnection between processing, structure and mechanical behaviour of MGs is highlighted. We further review the main categories of cardiovascular stents, the required mechanical properties of each category, and the conventional materials have been using to address these requirements. Then, we bridge between the mechanical requirements of stents, structural properties of MGs, and the corresponding stent design caveats. In particular, we discuss our recent findings on the feasibility of using MGs in self-expandable stents where our results show that a metallic glass based aortic stent can be crimped without mechanical failure. We further justify the safe deployment of this stent in human descending aorta. It is our intent with this review to inspire biodevice developers toward the realization of MG-based stents.

A CRISPR-Cas9-based gene drive platform for genetic interaction analysis in Candida albicans

Candida albicans is the leading cause of fungal infections; yet, complex genetic interaction analysis remains cumbersome in this diploid pathogen. Here, we developed a CRISPR-Cas9-based 'gene drive array' platform to facilitate efficient genetic analysis in C. albicans. In our system, a modified DNA donor molecule acts as a selfish genetic element, replaces the targeted site and propagates to replace additional wild-type loci. Using mating-competent C. albicans haploids, each carrying a different gene drive disabling a gene of interest, we are able to create diploid strains that are homozygous double-deletion mutants. We generate double-gene deletion libraries to demonstrate this technology, targeting antifungal efflux and biofilm adhesion factors. We screen these libraries to identify virulence regulators and determine how genetic networks shift under diverse conditions. This platform transforms our ability to perform genetic interaction analysis in C. albicans and is readily extended to other fungal pathogens.

Electroenhanced Antimicrobial Coating Based on Conjugated Polymers with Covalently Coupled Silver Nanoparticles Prevents Staphylococcus aureus Biofilm Formation

The incidence of hospital-acquired infections is to a large extent due to device-associated infections. Bacterial attachment and biofilm formation on surfaces of medical devices often act as seeding points of infection. To prevent such infections, coatings based on silver nanoparticles (AgNPs) are often applied, however with varying clinical success. Here, the traditional AgNP-based antibacterial technology is reimagined, now forming the base for an electroenhanced antimicrobial coating. To integrate AgNPs in an electrically conducting polymer layer, a simple, yet effective chemical strategy based on poly(hydroxymethyl 3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT-MeOH:PSS) and (3-aminopropyl)triethoxysilane is designed. The resultant PEDOT-MeOH:PSS-AgNP composite presents a consistent coating of covalently linked AgNPs, as shown by scanning electron microscopy and surface plasmon resonance analysis. The efficacy of the coatings, with and without electrical addressing, is then tested against Staphylococcus aureus, a major colonizer of medical implants. Using custom-designed culturing devices, a nearly complete prevention of biofilm growth is obtained in AgNP composite devices addressed with a square wave voltage input. It is concluded that this electroenhancement of the bactericidal effect of the coupled AgNPs offers a novel, efficient solution against biofilm colonization of medical implants.

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.

Comparative trial assessing suture techniques and types of urinary catheters in vesicourethral anastomotic tensile strength in a porcine model

PURPOSE

Vesicourethal anastomosis (VUA) during radical prostatectomy can be achieved using various suture plication techniques. Traditionally, an indwelling urinary catheter remains in-situ to facilitate the healing process of the reconstructed VUA. Compromise or rupture of this anastomosis may lead to acute urinary leak and subsequent urinoma or stricture formation. This ex-vivo porcine model aims to evaluate VUA tensile strength using different suture techniques and catheter types.

METHODS

Male porcine bladders were obtained and prostatectomy was performed. The specimens were randomized and VUA were created using 3-point interrupted, 6-point interrupted or 6 point continuous 3-0 monocryl suture. 20Fr catheters were utilized, specifically varying manufacturers (A and B) and catheter balloon shapes (round versus oval). The VUA model was placed within a reproducible pulley system and graduated weights were applied until failure of the catheter balloon or the model VUA. Model failure was defined as either 'VUA rupture', 'Catheter passage through VUA' or 'catheter failure'.

RESULTS

Twenty consecutive porcine bladders were prepared, tested and utilized for analysis. VUA reconstructed with 3-point fixation was more likely to suffer VUA rupture (p=0.025) compared to 6-point interrupted or 6-point continuous VUA. Higher tensile pressure causing catheter balloon rupture (p=0.009) was observed for Manufacturer A. Catheters with oval-balloon shape were more likely to dislodge past the VUA without disruption of the anastomosis (p=0.002).

CONCLUSIONS

During prostatectomy, anastomotic technique and catheter selection can significantly alter the tensile properties of the VUA. Further research is required to validate our findings in clinical models.

Carbon Ion Implantation: A Good Method to Enhance the Biocompatibility of Silicone Rubber

BACKGROUND

Silicone rubber and silicone rubber-based materials have been used as medical tissue implants in the field of plastic surgery for many years, but there are still some reports of adverse reactions to long-term implants. Earlier studies have shown that ion implantation could enhance the biocompatibility of biomaterials. However, whether ion implantation has a good effect on silicone rubber is unknown.

METHODS

Three types of carbon ion silicone rubber were obtained by implanting three doses of carbon ions. Then, the antibacterial adhesion properties and the in vivo host responses were evaluated. The antibacterial adhesion properties were examined by plate colony counting, fluorescence staining, and scanning electron microscopic observation. The host responses were evaluated by surveying inflammation and fiber capsule formation that developed after subcutaneous implantation in Sprague-Dawley rats for 7, 30, 90, and 180 days. In addition, the possible mechanism by which ion implantation enhanced the biocompatibility of the biomaterial was investigated and discussed.

RESULTS

Carbon ion silicone rubber exhibits less bacterial adhesion, less collagen deposition, and thinner and weaker tissue capsules. Immunohistochemical staining results for CD4, tumor necrosis factor-α, α-smooth muscle actin, and elastin showed the possible mechanism enhancing the biocompatibility of silicone rubber. These data indicate that carbon ion silicone rubber exhibits good antibacterial adhesion properties and triggers thinner and weaker tissue capsules. In addition, high surface roughness and high zeta potential may be the main factors that induce the unique biocompatibility of carbon ion silicone rubber.

CONCLUSION

Ion implantation should be considered for further investigation and application, and carbon ion silicone rubber could be a better biomaterial to decrease silicone rubber-initiated complications.

Intermittent urethral catheterisation: the reality of the lubricants and catheters in the clinical practice of a Brazilian service

AIMS AND OBJECTIVES

To identify how catheters and lubricants have been used among patients using intermittent urinary catheterisation in rehabilitation.

BACKGROUND

The clean intermittent urinary catheterisation technique is an invasive procedure can cause discomfort, pain and urethral traumas. The use of lubricants and lubricated urinary catheters reduces the friction between the catheter and the urethral mucosa, minimising the risks.

DESIGN

A descriptive exploratory design was used.

METHODS

Quantitative and descriptive study developed at a rehabilitation centre of a University Hospital in the interior of the state of São Paulo, Brazil, at the Intermittent Urinary Catheterisation Outpatient Clinic, between June 2012-December 2014. After ethical approval, the data were collected through an interview with the support of a semistructured questionnaire, held during the nursing consultation. Among the users, patients using intermittent urinary catheterisation were interviewed, over 18 years of age and minors younger than eight years accompanied. Descriptive statistical analysis was applied.

RESULTS

Most of 214 (100·0%) patients were interviewed were male, single, young adults and with a primary medical diagnosis of bone marrow injury and myelomeningocele. Most patients perform the urinary catheterisation between four and six times per day. For the procedure, the majority uses polyethylene (polyvinyl chloride) catheter and, as a lubricant, 2·0% lidocaine hydrochloride on the catheter itself. Many mention lack of sensitivity when passing the catheter.

CONCLUSION

In the study sample, a risk of urethral traumas was evidenced, related to the inappropriate use of catheters and lubricants. For the patients' safety, the professionals need to acknowledge the importance of the appropriate use of lubricants and lubricated catheters to implement evidence-based practices that mobilise public policies.

RELEVANCE TO CLINICAL PRACTICE

The use of evidences demonstrates that the appropriate use of lubricants for intermittent urinary catheterisation is fundamental for patient safety and the performance of the best practices.

Differences in Bacterial Colonization and Biofilm Formation Property of Uropathogens between the Two most Commonly used Indwelling Urinary Catheters

INTRODUCTION

Catheter Associated Urinary Tract Infections (CAUTI) are one of the most common cause of nosocomial infections. Many bacterial species show biofilm production, which provides survival benefit to them by providing protection from environmental stresses and causing decreased susceptibility to antimicrobial agents. Two most common types of catheters used in our setup are pure silicone catheter and silicone coated latex catheter. The advantage of pure silicone catheter for long term catheterization is well established. But there is still a controversy about any advantage of the silicone catheter regarding bacterial colonization rates and their biofilm production property.

AIMS

The aim of our study was to compare the bacterial colonization and the biofilm formation property of the colonizing bacteria in patients with indwelling pure silicone and silicone coated latex catheters.

MATERIALS AND METHODS

This prospective observational study was conducted in the Urology Department of our institute. Patients who needed catheterization for more than 5 days during the period July 2015 to January 2016 and had sterile precatheterisation urine were included in the study. Patients were grouped into 2 groups of 50 patients each, Group A with the pure silicone catheter and Group B with the silicone coated latex catheter. Urine culture was done on the 6(th) day of indwelling urinary catheter drainage. If growth was detected, then that bacterium was tested for biofilm production property by tissue culture plate method.

STATISTICAL ANALYSIS

Statistical analyses were performed using the Statistical Package for the Social Science Version 22 (SPSS-22).

RESULTS

After 5 days of indwelling catheterization, the pure silicone catheter had significantly less bacterial colonization than the silicone coated latex catheter (p-value=0.03) and the biofilm forming property of colonizing bacteria was also significantly less in the pure silicone catheter as compared to the silicone coated latex catheter (p-value=0.02). There were no significant differences in the colonizing bacteria in the 2 groups. In both the groups the most common bacteria were Escherichia coli.

CONCLUSION

The pure silicone catheter is advantageous over the silicone coated latex catheter in terms of incidence of bacterial colonization as well as the biofilm formation and hence in the management of CAUTI.