Evaluation of Polyethylene Glycol-Based Antimicrobial Coatings on Urinary Catheters in the Prevention of Escherichia coli Infections in a Rabbit Model

Long-term antifouling surfaces for urinary catheters

The presence of a variety of bacteria is an inevitable/indispensable part of human life. In particular, for patients, the existence and spreading of bacteria lead to prolonged treatment period with many more complications. The widespread use of urinary catheters is one of the main causes for the prevalence of infections. The necessity of long-term use of indwelling catheters is unavoidable in terms of the development of bacteriuria and blockage. As is known, since a permanent solution to this problem has not yet been found, research and development activities continue actively. Herein, polyethylene glycol (PEG)-like thin films were synthesized by a custom designed plasma enhanced chemical vapor deposition (PE-CVD) method and the long-term effect of antifouling properties of PEG-like coated catheters was investigated against Escherichia coli and Proteus mirabilis. The contact angle measurements have revealed the increase of wettability with the increase of plasma exposure time. The antifouling activity of surface-coated catheters was analyzed against the Gram-negative/positive bacteria over a long-term period (up to 30 days). The results revealed that PE-CVD coated PEG-like thin films are highly capable of eliminating bacterial attachment on surfaces with relatively reduced protein attachment without having any toxic effect. Previous statements were supported with SEM, XPS, FTIR spectroscopy, and contact angle analysis.

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.

Tackling catheter-associated urinary tract infections with next-generation antimicrobial technologies

Urinary catheters and other medical devices associated with the urinary tract such as stents are major contributors to nosocomial urinary tract infections (UTIs) as they provide an access path for pathogens to enter the bladder. Considering that catheter-associated urinary tract infections (CAUTIs) account for approximately 75% of UTIs and that UTIs represent the most common type of healthcare-associated infections, novel anti-infective device technologies are urgently required. The rapid rise of antimicrobial resistance in the context of CAUTIs further highlights the importance of such preventative strategies. In this review, the risk factors for pathogen colonization in the urinary tract are dissected, taking into account the nature and mechanistics of this unique environment. Moreover, the most promising next-generation preventative strategies are critically assessed, focusing in particular on anti-infective surface coatings. Finally, emerging approaches in this field and their likely clinical impact are examined.

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.

New Stent Technologies

Ureteral stents are an indispensable part of any (endo-) urologic practice. Despite the widely demonstrated advantages of stents, they also carry a considerable risk of side effects and complications, such as urinary symptoms, pain, hematuria, decreased quality of life, stent-related infection, and encrustation. Multiple pathways in preventing or mitigating these side effects and complications and improving stent efficacy have been and are being investigated, including stent architecture and design, biomaterials, and coatings. This article provides an update on currently researched and available stents as well as future perspectives.

An Amphiphilic Carbonaceous/Nanosilver Composite-Incorporated Urinary Catheter for Long-Term Combating Bacteria and Biofilms

Biofilms formed on urinary catheters remain a major headache in the modern healthcare system. Among the various kinds of biocide-releasing urinary catheters that have been developed to prevent biofilm formation, Ag nanoparticles (AgNPs)-coated catheters are of great promising potential. However, the deposition of AgNPs on the surface of catheters suffers from several inherent shortcomings, such as damage to the urethral mucosa, uncontrollable Ag ion kinetics, and unexpected systematic toxicity. Here, AgNPs-decorated amphiphilic carbonaceous particles (ACPs@AgNPs) with commendable dispersity in solvents of different polarities and broad-spectrum antibacterial activity are first prepared. The resulting ACPs@AgNPs exert good compatibility with silicone rubber, which enables the easy fabrication of urinary catheters using a laboratory-made mold. Therefore, ACPs@AgNPs not only endow the urinary catheter with forceful biocidal activity but also improve its mechanical properties and surface wettability. Hence, the designed urinary catheter possesses excellent capacity to resist bacterial adhesion and biofilm formation both in vitro and in an in vivo rabbit model. Specifically, a long-term antibacterial study highlights its sustainable antibacterial activity. Of note, no obvious toxicity or inflammation in rabbits was triggered by the designed urinary catheter in vivo. Overall, the hybrid urinary catheter may serve as a promising biocide-releasing urinary catheter for antibacterial and antibiofilm applications.