A comprehensive status update on modification of foley catheter to combat catheter-associated urinary tract infections and microbial biofilms

Surface engineering of biomedical catheters using N-acetyl cysteine functionalized carboxymethyl chitosan nanosystems to combat biofouling and device-associated infections

Functionalized anti-biofouling nanosystems were developed to engineer the surface of silicone catheters for mitigating the incidence of device-associated infections (DAIs). These infections are typically a consequence of microbial biofilms and antimicrobial resistance (AMR) which lead to increased hospitalization costs and mortality rates. Covalent coupling of N-acetyl cysteine (NAC) with O-carboxymethyl chitosan (O-CMC) was optimized to develop NAC-functionalized CMC nanosystems (NAC-CMC-NS). The coupling was confirmed by nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and 4, 6-trinitrobenzene sulfonic acid (TNBS) assay indicating 80 ± 2 % functionalization efficacy. Subsequently, meropenem-loaded NAC-CMC NS exhibited an average particle size of 273 ± 4.2 nm with 0.4 ± 0.03 polydispersity index (PDI), a zeta potential of -9.15 ± 0.5 mV and encapsulation efficiency (EE) of 67 ± 3.2 %. These functionalized NS employing the dual strategy of contact-killing and meropenem-release, exhibited exceptional antimicrobial activity leading to the 76 ± 1.5 % and 60 ± 1 % inhibition of E. coli and P. aeruginosa biofilms, respectively. After the successful grafting of functionalized NS onto silicone catheters, the resulting substrate remarkably reduced the bacterial colonization, offering a promising solution for reducing DAIs like ventilator-associated pneumonia (VAP) and catheter-associated urinary tract infections (CAUTI). Moreover, the excellent hemocompatibility and low cytotoxicity of these nanovesicles highlight their potential applications for clinical use.

Oral ciprofloxacin biofilm activity in a catheter-associated urinary tract infection model

BACKGROUND

Catheter-associated urinary tract infections (CA-UTIs) are a common hospital-acquired infection. We examined ciprofloxacin activity in a novel CA-UTI in vitro model.

METHODS

Three ATCC strains [Escherichia coli (ECO)-25922, Klebsiella pneumoniae (KPN)-700721, Pseudomonas aeruginosa (PAE)-27853] and 45 clinical urinary isolates were assessed. Biofilm mass and planktonic bacterial density were quantified during drug-free incubation (72 h) and following ciprofloxacin exposure (equivalent 750 mg orally q12h, 3 days).

RESULTS

ECO produced smaller biofilms (6.3 ± 1.1 log10 cfu/cm2) compared with KPN (7.1 ± 0.7 log10 cfu/cm2) and PAE (7.0 ± 1.2 log10 cfu/cm2), which extended along the entire catheter length. Following ciprofloxacin, all isolates with MIC > 4 mg/L had minimal biofilm disruption or planktonic kill. Ciprofloxacin resistance was most common in PAE isolates (10/16 isolates), compared with ECO (3/16 isolates) and KPN (6/16 isolates). Greater ciprofloxacin exposure (AUC0-24/MIC) was required for a 3 log10 biofilm kill for KPN (5858; R2 = 0.7774) compared with ECO (2117; R2 = 0.7907) and PAE (2485; R2 = 0.8260). Due to persistent growth in the bladder, ECO required greater ciprofloxacin exposure for a 3 log10 planktonic kill (5920; R2 = 0.8440) compared with KPN (2825; R2 = 0.9121) and PAE (1760; R2 = 0.8781). Monte Carlo simulation supported a 95% PTA for both a 3 log10 biofilm and planktonic kill for ECO and KPN isolates with MIC ≤ 0.5 mg/L and PAE isolates with MIC ≤ 1 mg/L.

CONCLUSIONS

In a novel CA-UTI model, following simulated ciprofloxacin therapy, KPN biofilms were comparatively more difficult to disrupt, ECO planktonic growth frequently persisted in the bladder, and PAE had greater propensity for emergence of ciprofloxacin resistance.

Mucosal injuries from indwelling catheters: A scoping review

There is currently a lack of clarity concerning the types and frequency of mucosa injuries occurring in urine bladders among patients with indwelling urine catheters that are of modern design and material. The aim of the study was to identify and present the available information regarding mucosa injuries in urine bladders among adult patients with indwelling urine catheters. The research question was: What is known about mucosa injuries in urine bladders among patients with indwelling urine catheters? A scoping review applying the patient, exposure, and outcome framework. A preliminary search was made to identify the keywords, and the selection process followed the Preferred Reporting Items for Systematic Review and Meta-Analysis flow diagram. The final search across five databases retrieved a total of 8,883 records. Eight studies from three countries were included and the studies used two main methods for collecting data. Eleven concepts to describe the injuries were identified, with a range from one to five studies using the same concept. Mucosa injuries, of which polypoid cystitis was most frequently reported, occurred in all studies, and ranged from 41% to 100% per study. The size of injured area varied between 0.5 to 2.5 cm. The posterior wall of the bladder was the most common area where injuries were found. This scoping review sheds light on the limited understanding of mucosal injuries in urine bladders among adult patients with indwelling urinary catheters. Moving forward, concerted efforts are warranted to bridge existing knowledge gaps to enhance our understanding of mucosal injuries and improve clinical outcomes for adult patients with indwelling urinary catheters. The lack of a robust scientific base for the impact of indwelling urine catheters on the urine bladder mucosa warrants future studies.

Antibacterial and antifouling materials for urinary catheter coatings

Implantable medical devices have played a significant role in improving both medical care and patients' quality of life. Urinary Catheters (UCs) are commonly utilized as a substitute for bladder drainage and urine collection to prevent urinary retention in patients. However, bacterial colonization and biofilm formation on the catheter surface are prone to occur, leading to catheter-associated urinary tract infections (CAUTIs) and other complications. In recent years, UC coatings have garnered increasing attention. In this review, various antifouling and antibacterial materials for UC coatings are summarized and their impacts on bacterial activities are linked to potential mechanisms of action. Additionally, this review provides an in-depth understanding of the current advancements in UC coatings by presenting the advantages, limitations, notable achievements, and latest research findings. Finally, it anticipates the prospective design and development trajectories of UC coatings in this domain. This holds paramount significance in advancing medical device technology. STATEMENT OF SIGNIFICANCE: Combating catheter-associated urinary tract infections is a major healthcare challenge, and urinary catheter (UC) coatings are considered promising candidates to counter these infections. In this review, various antifouling and antibacterial materials for UCs are summarized, and their impacts on bacterial activities are linked to potential mechanisms of action. Additionally, the review provides an in-depth understanding of the current advancements in UC coatings by presenting the advantages, limitations, notable achievements, and latest research findings. This holds paramount significance in advancing medical device technology. This review not only contributes to the scientific research but also sparks interest among readerships and other researchers in the study of safer and more effective UC coatings for improved patient outcomes.

Marine polysaccharides for antibiofilm application: A focus on biomedical fields

Microbial pathogens such as bacteria and fungi form biofilms, which represent substantial hurdles in treating human illness owing to their adaptive resistance mechanism to conventional antibiotics. Biofilm may cause persistent infection in a variety of bodily areas, including wounds, oral cavity, and vaginal canal. Using invasive devices such as implants and catheters contributes significantly to developing healthcare-associated infections because they offer an ideal surface for biofilm formation. Marine organisms produce a variety of polysaccharides, which have recently attracted worldwide attention due to their biochemical features, various applications, and advantageous properties such as bioactivity, biodegradability, and biocompatibility. Because of their antimicrobial and antibiofilm features, several polysaccharides such as chitosan, fucoidan, carrageenan, alginate, and hyaluronic acid have been used to treat infected wounds as well as ophthalmic, oral, and vaginal infections. In addition, marine polysaccharides are currently employed as coatings on medical devices and implant materials, alone or in combination with other bioactive substances or nanomaterials, to protect the materials' undertones from microbial contamination. This review discussed the recent advancements in marine polysaccharides and their derivatives as a therapeutic potential against biofilm-associated diseases. The potential obstacles in the scalability of their production, clinical translation, and/or regulatory hurdles have also been discussed.

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.

Repurposing albendazole as a potent inhibitor of quorum sensing-regulated virulence factors in Pseudomonas aeruginosa: Novel prospects of a classical drug

Pseudomonas aeruginosa has emerged as a critical superbug that poses a serious threat to public health. Owing to its virulence and multidrug resistance profiles, the pathogen demands immediate attention for devising alternate intervention strategies. In an attempt to repurpose drugs against P. aeruginosa, this preclinical study was aimed at investigating the antivirulence prospects of albendazole (AbZ), an FDA-approved anti-helminthic drug, recently predicted to disrupt quorum sensing (QS) in Chromobacterium violaceum. AbZ was scrutinized for its quorum quenching (QQ) prospects, effect on bacterial virulence, different motility phenotypes, and biofilm formation in vitro. Additionally, in silico analysis was employed to predict the molecular interactions between AbZ and QS receptors. At sub-inhibitory levels, AbZ demonstrated anti-QS activity and significantly abrogated AHL biosynthesis in P. aeruginosa. Moreover, AbZ significantly downregulated the transcript levels of QS- (lasI/lasR, rhlI/rhlR, and pqsA/pqsR) and QS-dependent virulence (aprA, lasA, lasB, plcH, and toxA) genes in P. aeruginosa. This coincided with reduced hemolysin, alginate, pyocyanin, rhamnolipids, total protease, and elastase production, thereby lowering phenotypic virulence. Molecular docking with AbZ further revealed strong associations and high binding energies with LasR (-8.8 kcal/mol), RhlR (-6.5 kcal/mol), and PqsR (-6.3 kcal/mol) receptors. AbZ also impeded bacterial motility and abolished EPS production, severely compromising pseudomonal biofilm formation. For the first time, AbZ was shown to interfere with QS circuitry and consequently disarming pseudomonal virulence. Hence, AbZ can be exploited for its antivirulence properties against P. aeruginosa.

Effect of DMPEI coating against biofilm formation on PVC catheter surface

Urinary tract infections (UTIs) are a significant cause of morbidity in healthcare systems and are prominently associated with applying urethral catheters, particularly in surgeries. Polyvinyl chloride (PVC) is extensively utilized in the fabrication of catheters. Biofilms, complex polymeric constructions, provide a protective milieu for cell multiplication and the enhancement of antibiotic resistance. Strategies to counteract biofilm development on medical apparatuses' surfaces incorporate antimicrobial agents such as N,N-dodecyl, and methyl polyethylenimine (DMPEI). This research endeavored to characterize the morphology of PVC and PVC-DMPEI surfaces utilizing Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) and to gauge hydrophobicity through contact angle measurements. Employing Escherichia coli, Staphylococcus aureus, and Candida albicans in adhesion assays enabled the assessment of DMPEI's efficacy in preventing microbial adherence to PVC. Butanol successfully solubilized 2 mg.mL-1 DMPEI without altering the PVC structure. SEM results substantiated the formation of a DMPEI layer on the PVC surface, which led to decreased surface roughness, as validated by AFM, and increased hydrophilicity, as demonstrated by contact angle evaluations. E. coli, S. aureus, and C. albicans exhibited significant adhesion reduction, 89.3%, 94.3%, and 86.6% on PVC-DMPEI surfaces. SEM visualizations confirmed reduced cellular colonization on PVC-DMPEI and highlighted considerable morphological modifications in E. coli. Consequently, DMPEI films effectively minimize the adhesion of E. coli, S. aureus, and C. albicans on PVC surfaces. DMPEI, with its potential as a protective coating for innovative medical devices, promises to inhibit biofilm adherence effectively.

Anti-virulence prospects of Metformin against Pseudomonas aeruginosa: A new dimension to a multifaceted drug

Metformin (MeT) is an FDA-approved drug with a myriad of health benefits. Besides being used as an anti-diabetic drug, MeT is also effective against various cancers, liver-, cardiovascular-, and renal diseases. This study was undertaken to examine its unique potential as an anti-virulence drug against an opportunistic bacterial pathogen, Pseudomonas aeruginosa. Due to the menace of multidrug resistance in pathogenic microorganisms, many novel or repurposed drugs with anti-virulence prospects are emerging as next-generation therapies with the aim to overshadow the application of existing antimicrobial regimens. The quorum sensing (QS) mechanisms of P. aeruginosa are an attractive drug target for attenuating bacterial virulence. In this context, the anti-QS potential of MeT was scrutinized using biosensor assays. MeT was comprehensively evaluated for its effects on different motility phenotypes, virulence factor production (phenotypic and genotypic expression) along with biofilm development in P. aeruginosa in vitro. At sub-lethal concentrations, MeT displayed prolific quorum quenching (QQ) ability and remarkably inhibited AHL biosynthesis in P. aeruginosa. Moreover, MeT (1/8 MIC) effectively downregulated the expression levels of various QS- and virulence genes in P. aeruginosa, which coincided with a notable reduction in the levels of alginate, hemolysin, pyocyanin, pyochelin, elastase, and protease production. In silico analysis through molecular docking also predicted strong associations between MeT and QS receptors of P. aeruginosa. MeT also compromised the motility phenotypes and successfully abrogated biofilm formation by inhibiting EPS production in P. aeruginosa. Hence, MeT may be repurposed as an anti-virulence drug against P. aeruginosa in clinical settings.