A large randomized clinical trial of a silver-impregnated urinary catheter: lack of efficacy and staphylococcal superinfection

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

Present-day healthcare employs several types of invasive devices, including urinary catheters, to improve medical wellness, the clinical outcome of disease, and the quality of patient life. Among urinary catheters, the Foley catheter is most commonly used in patients for bladder drainage and collection of urine. Although such devices are very useful for patients who cannot empty their bladder for various reasons, they also expose patients to catheter-associated urinary tract infections (CAUTIs). Catheter provides an ideal surface for bacterial colonization and biofilm formation, resulting in persistent bacterial infection and severe complications. Hence, rigorous efforts have been made to develop catheters that harbour antimicrobial and anti-fouling properties to resist colonization by bacterial pathogens. In this regard, catheter modification by surface functionalization, impregnation, blending, or coating with antibiotics, bioactive compounds, and nanoformulations have proved to be effective in controlling biofilm formation. This review attempts to illustrate the complications associated with indwelling Foley catheters, primarily focussing on challenges in fighting CAUTI, catheter colonization, and biofilm formation. In this review, we also collate scientific literature on catheter modification using antibiotics, plant bioactive components, bacteriophages, nanoparticles, and studies demonstrating their efficacy through in vitro and in vivo testing.

Promising applications of phyto-fabricated silver nanoparticles: Recent trends in biomedicine

The prospective contribution of phyto-nanotechnology to the synthesis of silver nanomaterials for biomedical purposes is attracting increasing interest across the world. Green synthesis of silver nanoparticles (Ag-NPs) through plants has been extensively examined recently, and it is now seen to be a green and efficient path for future exploitation and development of practical nano-factories. Fabrication of Ag-NPs is the process involves use of plant extracts/phyto-compounds (e.g.alkaloids, terpenoids, flavonoids, and phenolic compounds) to synthesise nanoparticles in more economical and feasible. Several findings concluded that in the field of medicine, Ag-NPs play a major role in pharmacotherapy (infection and cancer). Indeed, they exhibits novel properties but the reason is unclear (except some theoretical interpretation e.g. size, shape and morphology). But recent technological advancements help to address these questions by predicting the unique properties (composition and origin) by characterizing physical, chemical and biological properties. Due to increased list of publications and their application in the field of agriculture, industries and pharmaceuticals, issues relating to toxicity are unavoidable and question of debate. The present reviews aim to find out the role of plant extracts to synthesise Ag-NPs. It provides an overview of various phytocompounds and their role in the field of biomedicine (antibacterial, antioxidant, anticancer, anti-inflammatory etc.). In addition, this review also especially focused on various applications such as role in infection, oxidative stress, application in medical engineering, diagnosis and therapy, medical devices, orthopedics, wound healing and dressings. Additionally, the toxic effects of Ag-NPs in cell culture, tissue of different model organism, type of toxic reactions and regulation implemented to reduce associated risk are discussed critically. Addressing all above explanations, this review focus on the detailed properties of plant mediated Ag-NPs, its impact on biology, medicine and their commercial properties as well as toxicity.

Transforming medical device biofilm control with surface treatment using microfabrication techniques

Biofilm deposition on indwelling medical devices and implanted biomaterials is frequently attributed to the prevalence of resistant infections in humans. Further, the nature of persistent infections is widely believed to have a biofilm etiology. In this study, the wettability of commercially available indwelling medical devices was explored for the first time, and its effect on the formation of biofilm was determined in vitro. Surprisingly, all tested indwelling devices were found to be hydrophilic, with surface water contact angles ranging from 60° to 75°. First, we established a thriving Candida albicans biofilm growth at 24 hours. in YEPD at 30°C and 37°C plus serum in vitro at Cyclic olefin copolymer (COC) modified surface, which was subsequently confirmed via scanning electron microscopy, while their cellular metabolic function was assessed using the XTT cell viability assay. Surfaces with patterned wettability show that a contact angle of 110° (hydrophobic) inhibits C. albicans planktonic and biofilm formation completely compared to robust growth at a contact angle of 40° (hydrophilic). This finding may provide a novel antimicrobial strategy to prevent biofilm growth and antimicrobial resistance on indwelling devices and prosthetic implants. Overall, this study provides valuable insights into the surface characteristics of medical devices and their potential impact on biofilm formation, leading to the development of improved approaches to control and prevent microbial biofilms and re-infections.

Pseudomonas aeruginosa: Infections, Animal Modeling, and Therapeutics

Pseudomonas aeruginosa is an important Gram-negative opportunistic pathogen which causes many severe acute and chronic infections with high morbidity, and mortality rates as high as 40%. What makes P. aeruginosa a particularly challenging pathogen is its high intrinsic and acquired resistance to many of the available antibiotics. In this review, we review the important acute and chronic infections caused by this pathogen. We next discuss various animal models which have been developed to evaluate P. aeruginosa pathogenesis and assess therapeutics against this pathogen. Next, we review current treatments (antibiotics and vaccines) and provide an overview of their efficacies and their limitations. Finally, we highlight exciting literature on novel antibiotic-free strategies to control P. aeruginosa infections.

Cefmetazole Resistance Mechanism for Escherichia Coli Including ESBL-Producing Strains

Purpose

Cefmetazole (CMZ), a cephamycin antibiotic, is primarily used as a definitive therapy for Extended Spectrum β-Lactamase (ESBL)-producing Escherichia coli infections. However, the mechanism of CMZ resistance in E. coli is still unknown. To elucidate the resistance mechanism and to determine combined drugs for prevention of resistance acquisition.

Methods

Clinical isolates of 14 ESBL-producing E. coli and non-producing 12 isolates were used in in vitro testing of CMZ resistance acquisition. After 10-day of CMZ exposure (1st subculture), these strains were incubated in an antibacterial-free medium for 14-day. These strains were again exposed to CMZ for 10-day (2nd subculture) and confirmed for changes in MIC. For each strain detected after 1st subculture, each mRNA expression level of porin, chromosomal ampC, and drug-efflux pump was measured using real-time RT-PCR. Relebactam (REL) has the potency to recover antimicrobial activity against carbapenem-resistant Enterobacterales that has porin deficiency. REL was added to the CMZ dilution series, and MIC changes and those of porin were confirmed.

Results

Of these 26 strains, 15 strains (57.7%) acquired resistance after 1st subculture, but after passage culture on the antibacterial-free medium, 11 strains recovered susceptibility. These 11 strains showed resistance after 2nd subculture. The expression levels of ompF and ompC were significantly decreased in these strains (P<0.05). When REL was added, all strains suppressed resistance acquisition after 1st subculture. The mechanism was the activation of ompF.

Conclusion

Our results showed that the mRNA expression levels of genes encoding porin were decreased in the strains that acquired resistance due to CMZ exposure, and that ompF and ompC in particular were thought to be involved in the acquisition of resistance. The CMZ acquisition of resistance was also suppressed by the concomitant use of REL and actually suppressed the decrease in mRNA expression in ompF. It was confirmed that porin reactivated by REL.

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.

Catheter-associated urinary tract infections in patients who have undergone radical cystectomy for bladder cancer: A prospective randomized clinical study of two silicone catheters (clinical benefit of antibiotic silicone material)

Purpose

Materials and Methods

Results

Conclusions

Wound Antiseptics and European Guidelines for Antiseptic Application in Wound Treatment

Issues arising in wound healing are very common, and chronic wound infections affect approximately 1.5% of the population. The main substances used in wound washing, cleansing and treatment are antiseptics. Today, there are many compounds with a known antiseptic activity. Older antiseptics (e.g., boric acid, ethacridine lactate, potassium permanganate, hydrogen peroxide, iodoform, iodine and dyes) are not recommended for wound treatment due to a number of disadvantages. According to the newest guidelines of the Polish Society for Wound Treatment and the German Consensus on Wound Antisepsis, only the following antiseptics should be taken into account for wound treatment: octenidine (OCT), polihexanide (PHMB), povidone-iodine (PVP-I), sodium hypochlorite (NaOCl) and nanosilver. This article provides an overview of the five antiseptics mentioned above, their chemical properties, wound applications, side effects and safety.

Broad spectrum antimicrobial PDMS-based biomaterial for catheter fabrication

Background

In addition to the widespread use of antibiotics in healthcare settings, the current COVID-19 pandemic has escalated the emergence of antibiotic resistance. Nosocomial infections among hospitalized patients is a leading site for such resistant microbial colonization due to prolonged use of invasive devices and antibiotics in therapies. Invasive medical devices, especially catheters, are prone to infections that could accelerate the development of resistant microbes. Often, catheters - particularly urinary catheters - are prone to high infection rates. Antibiotic-coated catheters can reduce infection rates and although commercially available, are limited in efficacy and choices.

Methods

Herein, a novel and facile method to fabricate PMDS-based biomaterial for the development of antimicrobial eluting catheters is presented. Silicone based organic polymer polydimethylsiloxane (PDMS) was used to prepare a biomaterial containing novel polymeric imidazolium antimicrobial compound.

Results

It was found that the PDMS-based biomaterials could eradicate microbial colonization even after 60 days in culture with continuous microbial challenge, be recycled over multiple uses, stored at room temperature for long-term usage and importantly is biocompatible.

Conclusion

The PDMS-based biomaterial displayed biocidal functionality on microbes of clinical origin, which form major threats in hospital acquired infections.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-021-00235-5.

A Synergistic New Approach Toward Enhanced Antibacterial Efficacy via Antimicrobial Peptide Immobilization on a Nitric Oxide-Releasing Surface

Despite technological advancement, nosocomial infections are prevalent due to the rise of antibiotic resistance. A combinatorial approach with multimechanistic antibacterial activity is desired for an effective antibacterial medical device surface strategy. In this study, an antimicrobial peptide, nisin, is immobilized onto biomimetic nitric oxide (NO)-releasing medical-grade silicone rubber (SR) via mussel-inspired polydopamine (PDA) as a bonding agent to reduce the risk of infection. Immobilization of nisin on NO-releasing SR (SR-SNAP-Nisin) and the surface characteristics were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy and contact angle measurements. The NO release profile (7 days) and diffusion of SNAP from SR-SNAP-Nisin were quantified using chemiluminescence-based nitric oxide analyzers and UV-vis spectroscopy, respectively. Nisin quantification showed a greater affinity of nisin immobilization toward SNAP-doped SR. Matrix-assisted laser desorption/ionization mass spectrometry analysis on surface nisin leaching for 120 h under physiological conditions demonstrated the stability of nisin immobilization on PDA coatings. SR-SNAP-Nisin shows versatile in vitro anti-infection efficacy against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus in the planktonic and adhered states. Furthermore, the combination of NO and nisin has a superior ability to impair biofilm formation on polymer surfaces. SR-SNAP-Nisin leachates did not elicit cytotoxicity toward mouse fibroblast cells and human umbilical vein endothelial cells, indicating the biocompatibility of the material in vitro. The preventative and therapeutic potential of SR-SNAP-Nisin dictated by two bioactive agents may offer a promising antibacterial surface strategy.

Guidelines for Infection Control in the Urological Field, including Urinary Tract Management (revised second edition)

The Committee for the Development of Guidelines for Infection Control in the Urological Field, including Urinary Tract Management of the Japanese Urological Association, together with its systematic review team and external reviewers, have prepared a set of practice guidelines, an abridged version of which is published herein. These guidelines cover the following topics: (i) foundations of infection control, standard precautions, route-specific precautions, and occupational infection control (including vaccines); (ii) the relationship between urologists and infection control; (iii) infection control in urological wards and outpatient clinics; (iv) response to hepatitis B virus reactivation; (v) infection control in urological procedures and examinations; (vi) prevention of infections occurring in conjunction with medical procedures and examinations; (vii) responses to urinary tract tuberculosis and bacillus Calmette-Guérin; (viii) aseptic handling, cleaning, disinfection, and sterilization of urinary tract endoscopes (principles of endoscope manipulation, endoscope lumen cleaning, and disinfection); (ix) infection control in the operating room (principles of hand washing, preoperative rubbing methods, etc.); (x) prevention of needlestick and blood/bodily fluid exposure and response to accidental exposure; (xi) urinary catheter-associated urinary tract infection and purple urinary bag syndrome; and (xii) urinary catheter-associated urinary tract infections in conjunction with home care. In addressing these topics, the relevant medical literature was searched to the extent possible, and content was prepared for the purpose of providing useful information for clinical practice.

An antibacterial coated polymer prevents biofilm formation and implant-associated infection

To prevent infections associated with medical implants, various antimicrobial silver-coated implant materials have been developed. However, these materials do not always provide consistent antibacterial effects in vivo despite having dramatic antibacterial effects in vitro, probably because the antibacterial effects involve silver-ion-mediated reactive oxygen species generation. Additionally, the silver application process often requires extremely high temperatures, which damage non-metal implant materials. We recently developed a bacteria-resistant coating consisting of hydroxyapatite film on which ionic silver is immobilized via inositol hexaphosphate chelation, using a series of immersion and drying steps performed at low heat. Here we applied this coating to a polymer, polyetheretherketone (PEEK), and analyzed the properties and antibacterial activity of the coated polymer in vitro and in vivo. The ionic silver coating demonstrated significant bactericidal activity and prevented bacterial biofilm formation in vitro. Bio-imaging of a soft tissue infection mouse model in which a silver-coated PEEK plate was implanted revealed a dramatic absence of bacterial signals 10 days after inoculation. These animals also showed a strong reduction in histological features of infection, compared to the control animals. This innovative coating can be applied to complex structures for clinical use, and could prevent infections associated with a variety of plastic implants.

Combating Implant Infections: Shifting Focus from Bacteria to Host

The widespread use of biomaterials to support or replace body parts is increasingly threatened by the risk of implant-associated infections. In the quest for finding novel anti-infective biomaterials, there generally has been a one-sided focus on biomaterials with direct antibacterial properties, which leads to excessive use of antibacterial agents, compromised host responses, and unpredictable effectiveness in vivo. This review sheds light on how host immunomodulation, rather than only targeting bacteria, can endow biomaterials with improved anti-infective properties. How antibacterial surface treatments are at risk to be undermined by biomaterial features that dysregulate the protection normally provided by critical immune cell subsets, namely, neutrophils and macrophages, is discussed. Accordingly, how the precise modification of biomaterial surface biophysical cues, or the incorporation of immunomodulatory drug delivery systems, can render biomaterials with the necessary immune-compatible and immune-protective properties to potentiate the host defense mechanisms is reviewed. Within this context, the protective role of host defense peptides, metallic particles, quorum sensing inhibitors, and therapeutic adjuvants is discussed. The highlighted immunomodulatory strategies may lay a foundation to develop anti-infective biomaterials, while mitigating the increasing threat of antibacterial drug resistance.

Recent progress and strategies to develop antimicrobial contact lenses and lens cases for different types of microbial keratitis

Although contact lenses are widely used for vision correction, they are also the primary cause of a number of ocular diseases such as microbial keratitis (MK), etc. and inflammatory events such as infiltrative keratitis (IK), contact lens acute red eye (CLARE), contact lens-induced peripheral ulcer (CLPU), etc. These diseases and infiltrative events often result from microbial contamination of lens care solutions and lens cases that can be exacerbated by unsanitary lens care and extended lens wear. The treatment of microbial biofilms (MBs) on lens cases and contact lenses are complicated and challenging due to their resistance to conventional antimicrobial lens care solutions. More importantly, MK caused by MBs can lead to acute visual damage or even vision impairment. Therefore, the development of lens cases, lens care solutions, and contact lenses with effective antimicrobial performance against MK will contribute to the safe use of contact lenses. This review article summarizes and discusses different chemical approaches for the development of antimicrobial contact lenses and lens cases employing passive surface modifications, antimicrobial peptides, free-radical fabricating agents, quorum sensing quenchers, antibiotics, antifungal drugs and various metals and coatings with antimicrobial nanomaterials. The benefits and shortcomings of these approaches are assessed, and alternative solutions for future developments are discussed.

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.

Use of non-pharmacological interventions during urinary catheter insertion for reducing urinary tract infections in non-immunocompromised adults. A systematic review

Introduction: Catheter-associated urinary tract infections (CAUTI) account for up to 30% of hospital-acquired infections. In this regard, several studies have reported the use of non-pharmacological interventions during urinary catheter insertion aimed at reducing the occurrence rate of CAUTI.Objective: To assess the safety and effectiveness of using non-pharmacological interventions during urinary catheter insertion aimed at reducing the risk of contracting infections in non-immunocompromised adults.Material and methods. A literature review was conducted in MEDLINE, Embase, and LILACS databases. Only randomized clinical trials comparing the use of non-pharmacological interventions with the use of placebos, the use of pharmacological interventions or the lack of any intervention at all during catheter insertion were included.Results: Eight studies were retrieved (8.718 participants). Based on the evidence found in the review (low-quality and very low-quality evidence according to the quality classification GRADE system), using non-pharmacological interventions reduces the frequency of asymptomatic bacteriuria episodes (RR: 0.67, 95%CI 0.48-0.94; 7 studies) or minor side effects (RR: 0.84, 95% CI 0.74-0.96; 4.157; 2 studies), but does not reduce the occurrence rate of symptomatic urinary tract infections (RR: 0.90, 95%CI 0.61-1.35; 4 studies) or improves quality-of-life scores (MD –0.01 EQ-5D scale; 95%CI (-0.03)-(0.01), 1 study).Conclusion: The use of non-pharmacological interventions during urinary catheter insertion does not imply any risk at all, instead it could help reduce the occurrence rate of infections associated with this procedure, such as asymptomatic bacteriuria and minor adverse events; however, there is very little evidence (in fact, low and very low quality evidence) to make conclusions on the effectiveness of these interventions.

Development of dual anti-biofilm and anti-bacterial medical devices

Silicone catheters impregnated with antibiotics and coated with an anti-attachment polyacrylate produce a device with dual anti-biofilm and anti-bacterial properties.

Persistent Barriers to Timely Catheter Removal Identified from Clinical Observations and Interviews

BACKGROUND

Indwelling urinary and vascular catheters are valuable devices in patient care, but prolonged or unnecessary use increases the risk of infectious and noninfectious catheter harms.

METHODS

To understand persistent barriers to detecting and removing unnecessary catheters, researchers conducted a multimethod qualitative study that included observations and in-person interviews with clinicians working on a progressive care unit of a large hospital. Observations consisted of shadowing nurses during shift change and while admitting patients, and observing physicians during morning rounds. Observational data were gathered using unstructured field notes. Interviews were conducted using a semistructured guide, audio-recorded, and transcribed. Qualitative content analysis was conducted to identify main themes.

RESULTS

Barriers to timely removal identified during 19 interviews with clinicians and 133 hours of field observations included physicians not routinely reviewing catheter necessity during rounds, catheters going unnoticed or hidden under clothing, common use of "Do Not Remove" orders, and little or no discussion of catheters among clinicians. Five overall themes emerged: (1) Catheter data are hard to find, not accurate, or not available; (2) Catheter removal is not a priority; (3) Confusion exists about who has authority to remove catheters; (4) There is a lack of agreement on, and awareness of, standard protocols and indications for removal; and (5) Communication barriers among clinicians create challenges.

CONCLUSION

To address barriers and facilitate detection and timely removal, clinicians need ready access to accurate catheter data, more clearly delineated clinician roles for prompting removal, effective tools to facilitate discussions about catheter use, and standardized catheter removal protocols.

Does antimicrobial coating and impregnation of urinary catheters prevent catheter-associated urinary tract infection? A review of clinical and preclinical studies

Introduction: Catheter-associated urinary tract infection (CAUTI) is one of the most common nosocomial infections in hospitals, accounting for 36% of all health care-associated infections. Areas covered: We aimed to address the potential impact of antimicrobial coating of catheter materials for the prevention of CAUTI and to analyze the progress made in this field. We conducted literature searches in the PubMed, Embase, and Cochrane Library databases, and found 578 articles. Data from 60 articles in either the preclinical or clinical stage were analyzed in this expert review. Expert opinion: The literature review revealed many promising methods for preventing CAUTI. Recent studies have suggested the combination of silver-based products and antibiotics, owing to their synergistic effect, to help address the problem of antibiotic resistance. Other coating materials that have been tested include nitric oxide, chlorhexidine, antimicrobial peptides, enzymes, and bacteriophages. Because of heterogeneity among studies, it is difficult to reliably comment on the clinical efficacy of different coating materials. Future research should focus on double-blind randomized clinical trials for evaluating the role of these potential coating agents.

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.

The antimicrobial efficacy of zinc doped phosphate-based glass for treating catheter associated urinary tract infections

In this study, a series of phosphate-based glasses; (P₂O₅)₅₀(Na₂O)₂₀(CaO)_30-x (ZnO)_x were prepared with increasing concentration of zinc oxide to determine the antimicrobial effect against clinically relevant microorganisms. The addition of 1 and 3 mol% zinc oxide decreased glass degradation however a higher dissolution rate was observed for 5 and 10 mol% ZnO. The antimicrobial results showed a concentration dependent effect on the viability of microorganisms. When in direct contact zinc doped glasses showed a complete kill, within 24 h, against Escherichia coli and a significant (p < 0.01) kill was observed against Staphylococcus aureus however the effect of dissolution products was not seen until 48 h. Furthermore, the cytotoxic studies showed no toxic effects on the viability of uroepithelial cells. This study has shown that zinc doped phosphate-based glasses can potentially be used to prevent/treat catheter associated urinary tract infections.

A randomized clinical trial comparing Nitrofurazone-coated and uncoated urinary catheters in kidney transplant recipients: Results from a pilot study

BACKGROUND

Urinary tract infections are frequent complications early after kidney transplantation, and the use of antimicrobial coated catheters in settings other than transplantation has shown promising results for infection prevention. The purpose of this study was to compare the efficacy of Nitrofurazone-coated silicone urinary catheters with non-impregnated silicone urinary catheters in reducing bacteriuria and urinary tract infections in kidney transplant recipients.

METHODS

This single-center study, randomized controlled trial at the Hospital do Rim, a tertiary referral center in kidney transplantation, located in São Paulo, Brazil. Subjects involved living donor kidney transplant recipients, and were randomized 1:1 ratio with a computer-generated system to a Nitrofurazone-coated silicone urinary catheter and non-impregnated silicone urinary catheter from March 2013 to December 2014. Patients with asymptomatic bacteriuria or urinary tract infection at baseline, deceased kidney transplant donors, patients with known hypersensitivity to nitrofurantoin, pregnancy, and those refusing to sign the informed consent form were excluded from the study.

RESULTS

Two hundred fourteen subjects were randomized and one hundred seventy-six completed the study. There were no differences in the rates of asymptomatic bacteriuria (12.5% in the Nitrofurazone group and 11.4% in the control group, P = 0.99) and urinary tract infection (8% and 6.8%, P = 0.99) and the incidence of side effects was more frequent in the Nitrofurazone-impregnated silicone urinary catheter group (46.6% and 26.1%, P = 0.007).

CONCLUSION

The study suggests that there is no beneficial effect of the employment of Nitrofurazone-coated urinary catheter.

TRIAL REGISTRATION NUMBER

ISRCTN57888785.

Silver-Impregnated Dressing Does Not Decrease Incidence of Surgical Site Infection After Adult Cardiac Surgery

OBJECTIVE

Sternal wound infections complicate 1% to 8% of cardiac surgeries and carry significant morbidity. We investigated the utility of silver-impregnated dressing in decreasing sternal wound infections after sternotomy cases.

METHODS

A single-institution cohort study was performed as part of a quality improvement trial of a new sternal dressing. Five hundred fifty-seven sternotomy cases were performed in 2015 with application of a traditional gauze dressing. In 2016, 682 sternotomy cases were performed with the use of a commercially available silver-impregnated dressing. Prospectively identified metrics were analyzed for each patient population along with nursing assessments and structured questionnaires.

RESULTS

Baseline characteristics of patients in traditional gauze and silver-impregnated dressing groups were similar. Morbidity and mortality were similar. Nine (1.6%) and 12 (1.8%) sternal wound infections were reported in traditional gauze and silver-impregnated dressing groups, respectively. There was no difference in the rate of sternal wound infections (P = 0.80). The number of organ space infections (3) and deep sternal wound infections (3) was the same; however, the number of superficial infections was greater in the silver-impregnated dressing cohort (3 vs. 6). Among patients in either group with sternal wound infection, there were no differences in the proportion of superficial infections (44% vs. 50%, P = 0.8) or the organism cultured (67% vs. 50% staphylococcus, P = 0.45). A total of 22% of patients reported "not satisfied" with silver-impregnated dressing.

CONCLUSIONS

Silver dressings did not reduce sternal wound infection after sternotomy for cardiac surgery in a large-cohort study. We discontinued the routine use of silver dressings for adult cardiac surgery based on these results because traditional gauze likely represents an equally effective and less costly alternative.

The attributable cost of catheter-associated urinary tract infections in the United States: A systematic review

BACKGROUND

Catheter-associated urinary tract infections (CAUTIs) are the most common healthcare-acquired condition. The attributable cost of CAUTIs is frequently cited to be approximately $1,000. However, there is a paucity of recent literature that confirms this estimate. The purpose of this study was to perform a systematic review of the literature that estimates the attributable cost of CAUTIs in the United States.

METHODS

A systematic review was conducted using Pubmed. Studies conducted between the years 2000 and 2017, conducted at a facility within the United States, and that used novel patient-level cost data were included. Attributable cost estimates were adjusted for inflation to 2016 U.S. dollars using the medical care component of the Consumer Price Index.

RESULTS

Only 4 articles met our inclusion criteria. Adjusted to 2016 U.S. dollars, the attributable costs of a CAUTI as reported in these studies were: $876 (inpatient cost to the hospital for additional diagnostic tests and medications); $1,764 (inpatient cost to Medicare for non-intensive care unit [ICU] patients); $7,670 (inpatient and outpatient costs to Medicare); $8,398 (inpatient cost to the hospital for pediatric patients); and $10,197 (inpatient cost to Medicare for ICU patients).

CONCLUSIONS

The cost of a CAUTI ranges widely depending on population, patient acuity, and cost perspective. Attributable costs likely exceed $1,000. Additional research is needed to assess the full economic effect of CAUTIs.

On-demand release of Candida albicans biofilms from urinary catheters by mechanical surface deformation

Candida albicans is a leading cause of catheter-associated urinary tract infections and elimination of these biofilm-based infections without antifungal agents would constitute a significant medical advance. A novel urinary catheter prototype that utilizes on-demand surface deformation is effective at eliminating bacterial biofilms and here the broader applicability of this prototype to remove fungal biofilms has been demonstrated. C. albicans biofilms were debonded from prototypes by selectively inflating four additional intralumens surrounding the main lumen of the catheters to provide the necessary surface strain to remove the adhered biofilm. Deformable catheters eliminated significantly more biofilm than the controls (>90% eliminated vs 10% control; p < 0.001). Mechanical testing revealed that fungal biofilms have an elastic modulus of 45 ± 6.7 kPa with a fracture energy of 0.4-2 J m^-2. This study underscores the potential of mechanical disruption as a materials design strategy to combat fungal device-associated infections.

Antimicrobial Coating of Devices for Prevention of Infection: Principles and Protection

Device-associated infections are responsible for about half of nosocomial infections and can cause major medical and economical sequelae. Despite adherence to basic infection control measures, which constitute the mainstay for preventing infection, infections associated with certain devices continue to exist at unacceptably high rates. Potentially-preventive, antimicrobial-utilizing strategies include systemic antibiotic prophylaxis and local administration of antimicrobial agents (antibiotics or antiseptics), which includes antimicrobial irrigation of the surgical field, placement of antimicrobial carriers, antiseptic cleansing of the skin, dipping of surgical implants in antimicrobial solutions, and inserting antimicrobial-coated implants. Since bacterial colonization of the indwelling device is a prelude to infection, prevention of device colonization may lead to a lower rate of clinical infection. Different approaches for antimicrobial coating of devices have been variably successful in preventing device-associated infections. Optimal characteristics of antimicrobial coating can help predict the likelihood and degree of clinical protection against infection. This review addresses the impact of device-related infection, antimicrobial-utilizing approaches for preventing infection, clinical protection afforded by different types of antimicrobial coating, characteristics that predict the ability of antimicrobial coating of devices to prevent clinical infection, and future directions of antimicrobial coating.

Anti-Adherent Biomaterials for Prevention of Catheter Biofouling

Medical device-associated infections present a leading global healthcare challenge, and effective strategies to prevent infections are urgently required. Herein, we present an innovative anti-adherent hydrogel copolymer as a candidate catheter coating with complementary hydrophobic drug-carrying and eluting capacities. The amphiphilic block copolymer, Poloxamer 188, was chemically-derivatized with methacryloyl moieties and copolymerized with the hydrogel monomer, 2-hydroxyethyl methacrylate. Performance of the synthesized copolymers was evaluated in terms of equilibrium swelling, surface water wettability, mechanical integrity, resistance to encrustation and bacterial adherence, and ability to control release of the loaded fluoroquinolone antibiotic, ofloxacin. The developed matrices were able to provide significant protection from fouling, with observed reductions of over 90% in both adherence of the common urinary pathogen Escherichia coli and encrusting crystalline deposits of calcium and magnesium salts relative to the commonly employed hydrogel, poly (hydroxyethyl methacrylate). Additionally, the release kinetics of a loaded hydrophobic drug could be readily tuned through facile manipulation of polymer composition. This combinatorial approach shows significant promise in the development of suitable systems for prevention of catheter-associated infections.

Update on voiding dysfunction managed with suprapubic catheterization

As the population ages the prevalence of long-term urinary catheters, especially in the elderly, is going to increase. Urinary catheters are usually placed to manage urinary retention or incontinence that cannot be managed any other way. There is significant morbidity associated with an indwelling catheter. The commonest problems are catheter blockages, infection and bladder stones. These will occur with a similar incidence with either a suprapubic or a urethral catheter. Urethral complications such as strictures, scrotal infection and erosion are less common with suprapubic catheterization (SPC). However the benefit of having a SPC needs to be balanced against the risks involved in inserting the catheter suprapubically. Patient reported symptoms show that a SPC is more comfortable and better tolerated than a urethral catheter. However there needs to be more research into developing better catheters that reduce the frequency of urinary infections and blockages and hence catheter morbidity.

Silver-Coated Megaprosthesis of the Proximal Tibia in Patients With Sarcoma

BACKGROUND

Proximal tibia arthroplasty is associated with high rates of infection. This study is the largest one that has compared the infection rates with titanium vs silver-coated megaprostheses in patients treated for sarcomas.

METHODS

The infection rate in 98 patients with sarcoma or giant-cell tumor in the proximal tibia who underwent placement of a titanium (n = 42) or silver-coated (n = 56) megaprosthesis (MUTARS) was assessed, along with the treatments administered for any infection.

RESULTS

As the primary end point of the study, the rates of infection were 16.7% in the titanium group and 8.9% in the silver group, resulting in 5-year prosthesis survival rates of 90% in the silver and 84% in the titanium group. Whereas in the titanium group 37.5% of patients ultimately had to undergo amputation in the present study, these mutilating surgical procedures were only necessary in the silver group in one patient (14.3%).

CONCLUSION

The use of silver-coated prosthesis reduced the infection rate in a relatively large and homogeneous group of patients. In addition, less-aggressive treatment of infection was possible in the group with silver-coated prosthesis.

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.

Can a Silver-Coated Arthrodesis Implant Provide a Viable Alternative to Above Knee Amputation in the Unsalvageable, Infected Total Knee Arthroplasty?

BACKGROUND

In the unsalvageable, infected total knee arthroplasty, knee arthrodesis is one treatment option with lower reported reinfection rates compared with repeated 2-stage revision and improved function compared with amputation. One possible method for reducing incidence of recurrent infection treated by arthrodesis is the use of a silver-coated implant. We report our experience of silver-coated arthrodesis nails used for managing infected revision arthroplasty. We primarily assess the rate of reinfection and rate of amputation and report functional outcome measures.

METHODS

Retrospective analysis of all patients undergoing knee arthrodesis with a silver-coated arthrodesis nail between 2008 and 2014. Patient-reported data were recorded prearthrodesis and postarthrodesis (Oxford Knee Score and Short Form-36) as well as evidence of recurrent of infection, subsequent surgery, and the necessity for amputation.

RESULTS

Eight patients underwent arthrodesis using the silver-coated arthrodesis nail. Mean duration of follow-up was 16 months (5-35 months). At the point of follow-up, there were no amputations, deaths, or implant revisions. One case of recurrent infection was successfully treated with washout and debridement. The mean prearthrodesis and postarthrodesis Oxford Knee Score difference was +8.9 points (P = .086) with significantly improved pain (P = .019), night pain (P = .021), and ease of standing (P = .003).

CONCLUSION

Arthrodesis of the knee using a silver-coated intramedullary device is successful in eradicating infection and allowing limb conservation. Where infection does recur, this can be successfully treated with implant retention. The use of a silver-coated arthrodesis nail should be considered as an alternative to amputation for patients with a multiply revised and infected total knee arthroplasty.

First report of macroscopic biofilm formation caused by Candida albicans on silver hydrogel-coated urinary catheters

We report macroscopic biofilms on silver hydrogel-coated urinary catheters in 2 patients from 2 different intensive care units. The catheters were removed on observation of a white, jelly layer on the catheters, respectively, 9 and 21 days after insertion. Yeast cells and pseudohyphal structures were observed with microscopy. Both isolates were identified as Candida albicans. To our knowledge, these are the first cases demonstrating the formation of macroscopic biofilm layers on silver nitrate-coated catheters in the literature.

Antibacterial potency of different deposition methods of silver and copper containing diamond-like carbon coated polyethylene

Background

Antibacterial coatings of medical devices have been introduced as a promising approach to reduce the risk of infection. In this context, diamond-like carbon coated polyethylene (DLC-PE) can be enriched with bactericidal ions and gain antimicrobial potency. So far, influence of different deposition methods and ions on antimicrobial effects of DLC-PE is unclear.

Methods

We quantitatively determined the antimicrobial potency of different PE surfaces treated with direct ion implantation (II) or plasma immersion ion implantation (PIII) and doped with silver (Ag-DLC-PE) or copper (Cu-DLC-PE). Bacterial adhesion and planktonic growth of various strains of S. epidermidis were evaluated by quantification of bacterial growth as well as semiquantitatively by determining the grade of biofilm formation by scanning electron microscopy (SEM). Additionally silver release kinetics of PIII-samples were detected.

Results

(1) A significant (p < 0.05) antimicrobial effect on PE-surface could be found for Ag- and Cu-DLC-PE compared to untreated PE. (2) The antimicrobial effect of Cu was significantly lower compared to Ag (reduction of bacterial growth by 0.8 (Ag) and 0.3 (Cu) logarithmic (log)-levels). (3) PIII as a deposition method was more effective in providing antibacterial potency to PE-surfaces than II alone (reduction of bacterial growth by 2.2 (surface) and 1.1 (surrounding medium) log-levels of PIII compared to 1.2 (surface) and 0.6 (medium) log-levels of II). (4) Biofilm formation was more decreased on PIII-surfaces compared to II-surfaces. (5) A silver-concentration-dependent release was observed on PIII-samples.

Conclusion

The results obtained in this study suggest that PIII as a deposition method and Ag-DLC-PE as a surface have high bactericidal effects.

A Prospective Trial of a Novel, Silicone-Based, Silver-Coated Foley Catheter for the Prevention of Nosocomial Urinary Tract Infections

Objective.

To evaluate the efficacy of silicone-based, silver ion–impregnated urinary catheters in the prevention of nosocomial urinary tract infections (NUTIs).

Design.

Prospective, crossover study to compare the efficacy of a silicone-based, hydrogel-coated, silver-impregnated Foley catheter with that of a silicone-based, hydrogel-coated catheter in the prevention of NUTIs.

Setting.

Adult medical and surgical wards of a university teaching hospital.

Results.

A total of 3,036 patients with catheters were evaluated; 1,165 (38%) of the catheters were silver impregnated, and 1,871 (62%) were not silver impregnated. Study groups were not identical; there were more men, a shorter duration of catheterization, and fewer urine cultures per 1,000 catheter-days in the silver catheter group. The rate of NUTIs per 1,000 Foley-days was 14.29 in the silver catheter group, compared with 16.15 in the nonsilver catheter group (incidence rate ratio, 0.88; 95% confidence interval, 0.70-1.11;P= .29). The median length of catheterization prior to the onset of a urinary tract infection (ie, exposure time) was 4 days for each group. There were no differences in the recovery of gram-positive, gram-negative, or fungal organisms in NUTIs. In a multivariate survival analysis, no factors, including silver catheters, were protective against NUTI.

Conclusions.

Unlike previous trials of latex-based, silver ion–impregnated Foley catheters, we found that silicone-based, silver-impregnated Foley catheters were not effective in preventing NUTIs; however, this study was affected by differences in the study groups. Prospective trials remain important in assessing the efficacy and cost-effectiveness of new silver-coated products.

Strategies to Prevent Catheter-Associated Urinary Tract Infections in Acute Care Hospitals: 2014 Update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their catheter-associated urinary tract infection (CAUTI) prevention efforts. This document updates “Strategies to Prevent Catheter-Associated Urinary Tract Infections in Acute Care Hospitals,” published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

A novel hydroxyapatite film coated with ionic silver via inositol hexaphosphate chelation prevents implant-associated infection

Various silver-coated implants have been developed to prevent implant-associated infections, and have shown dramatic effects in vitro. However, the in vivo results have been inconsistent. Recent in vitro studies showed that silver exerts antibacterial activity by mediating the generation of reactive oxygen species in the presence of oxygen. To maintain its antibacterial activity in vivo, the silver should remain in an ionic state and be stably bound to the implant surface. Here, we developed a novel bacteria-resistant hydroxyapatite film in which ionic silver is immobilized via inositol hexaphosphate chelation using a low-heat immersion process. This bacteria-resistant coating demonstrated significant antibacterial activity both in vitro and in vivo. In a murine bioluminescent osteomyelitis model, no bacteria were detectable 21 days after inoculation with S. aureus and placement of this implant. Serum interleukin-6 was elevated in the acute phase in this model, but it was significantly lower in the ionic-silver group than the control group on day 2. Serum C-reactive protein remained significantly higher in the control group than the ionic-silver group on day 14. Because this coating is produced by a low-heat immersion process, it can be applied to complex structures of various materials, to provide significant protection against implant-associated infections.

Urinary catheters: history, current status, adverse events and research agenda

For more than 3500 years, urinary catheters have been used to drain the bladder when it fails to empty. For people with impaired bladder function and for whom the method is feasible, clean intermittent self-catheterization is the optimal procedure. For those who require an indwelling catheter, whether short- or long-term, the self-retaining Foley catheter is invariably used, as it has been since its introduction nearly 80 years ago, despite the fact that this catheter can cause bacterial colonization, recurrent and chronic infections, bladder stones and septicaemia, damage to the kidneys, the bladder and the urethra, and contribute to the development of antibiotic resistance. In terms of medical, social and economic resources, the burden of urinary retention and incontinence, aggravated by the use of the Foley catheter, is huge. In the UK, the harm resulting from the use of the Foley catheter costs the National Health Service between £1.0-2.5 billion and accounts for ∼2100 deaths per year. Therefore, there is an urgent need for the development of an alternative indwelling catheter system. The research agenda is for the new catheter to be easy and safe to insert, either urethrally or suprapubically, to be retained reliably in the bladder and to be withdrawn easily and safely when necessary, to mimic natural physiology by filling at low pressure and emptying completely without damage to the bladder, and to have control mechanisms appropriate for all users.

Catheter-associated urinary tract infection: Role of the setting of catheter insertion

BACKGROUND

This study aimed to describe the epidemiology of catheter-associated urinary tract infections (CAUTIs) in patients admitted to a surgical ward in Central Italy and to analyze the associated risk factors.

METHODS

An active surveillance program for CAUTI was carried out in patients catheterized for at least 48 hours. Place of catheter insertion (operating room, hospital ward, cystoscopy room, emergency care unit), indication for catheterization and its duration, among other risk factors were monitored until discharge. Antibiotic resistance profiles of isolates were analyzed.

RESULTS

There were 641 catheterized patients monitored for CAUTI onset. Of these, 40 (6.2%) developed a CAUTI (rates were 15.1/1,000 catheter days, 95% confidence interval [CI], 11.9-22.6; 8.7/1,000 patient days, 95% CI, 6.9-13.1). Patients with CAUTI were older (P < .05) and their durations of hospitalization and catheterization were both longer compared with those who were not affected (P < .05). Catheterization >4 days (odds ratio [OR] = 8.21; 95% CI, 3.79-17.73; P < .05) and place of catheter insertion different from the operating room (OR = 7.9; 95% CI, 2.83-22.08; P < .05, for catheters placed in the ward) were associated with CAUTI. Among the micro-organisms isolated in CAUTIs, the most common were Pseudomonas aeruginosa (41.5%), Klebsiella pneumoniae (19.5%), and Escherichia coli (12.2%); 82.5% of them were resistant to different classes of antibiotics.

CONCLUSION

These results highlight the role played by the setting of catheter insertion in CAUTIs onset, therefore reflecting the importance of hand hygiene and proper aseptic insertion techniques as crucial determinants in CAUTIs prevention.

Retrospective evaluation of the incidence of early periprosthetic infection with silver-treated endoprostheses in high-risk patients: case-control study

We conducted a case-control study to examine the merit of silver-coated tumour prostheses. We reviewed 85 patients with Agluna-treated (silver-coated) tumour implants treated between 2006 and 2011 and matched them with 85 control patients treated between 2001 and 2011 with identical, but uncoated, tumour prostheses. In all, 106 men and 64 women with a mean age of 42.2 years (18.4 to 90.4) were included in the study. There were 50 primary reconstructions (29.4%); 79 one-stage revisions (46.5%) and 41 two-stage revisions for infection (24.1%). The overall post-operative infection rate of the silver-coated group was 11.8% compared with 22.4% for the control group (p = 0.033, chi-square test). A total of seven of the ten infected prostheses in the silver-coated group were treated successfully with debridement, antibiotics, and implant retention compared with only six of the 19 patients (31.6%) in the control group (p = 0.048, chi-square test). Three patients in the silver-coated group (3.5%) and 13 controls (15.3%) had chronic periprosthetic infection (p = 0.009, chi-square test). The overall success rates in controlling infection by two-stage revision in the silver-coated group was 85% (17/20) compared with 57.1% (12/21) in the control group (p = 0.05, chi-square test). The Agluna-treated endoprostheses were associated with a lower rate of early periprosthetic infection. These silver-treated implants were particularly useful in two-stage revisions for infection and in those patients with incidental positive cultures at the time of implantation of the prosthesis. Debridement with antibiotic treatment and retention of the implant appeared to be more successful with silver-coated implants.

Effects of Baseplates of Orthodontic Appliances with in situ generated Silver Nanoparticles on Cariogenic Bacteria: A Randomized, Double-blind Cross-over Clinical Trial

AIM

Polymethyl-methacrylate (PMMA) is commonly used primarily for baseplates of orthodontic appliances (BOA). The activities of cariogenic bacteria in biofilm on these surfaces may contribute to dental caries, gingival inflammation and periodontal disease. The PMMA incorporated with nanoparticles of silver (NanoAg-I-PMMA) and NanoAg in situ in PMMA (NanoAg-IS-PMMA) have been shown to control the growth of cariogenic bacteria, but clinical trial of anti-cariogenic application of these novel materials in orthodontics has not been evaluated. The main aim of the study is to compare the clinical effectiveness of using NanoAg-IS-PMMA and NanoAg-I-PMMA for construction of new BOA in inhibiting the planktonic growth and biofilm formation of the cariogenic bacteria.

MATERIALS AND METHODS

Twenty four patients with a median age of 12.6 years (7-15) harboring Streptococcus mutans, Streptococcus sobrinus and Lactobacillus acidophilus as well as Lactobacillus casei participated in the randomized, double-blind, cross-over study. The experimental BOA, NanoAg-IS-BOA and NanoAg-I-BOA, contained 0.5% w/w NanoAg while the control BOA was standard PMMA. Antibacterial effect of NanoAg-IS-BOA and NanoAg-I-BOA was assessed against test cariogenic bacteria by planktonic and biofilm bacterial cells growth inhibition.

RESULTS

The average levels of test cariogenic bacteria in saliva decreased about 2 to 70 fold (30.9-98.4%) compared to baseline depending on the microorganism type and test BOA. Biofilm inhibition analysis demonstrated that NanoAg-I-BOA and NanoAg-IS-BOA inhibited the biofilm of all test bacteria by 20.1 to 79.9% compared to BOA. NanoAg-IS-BOA had a strong anti-biofilm effect against S. mutans, S. sobrinus and L. casei. However, NanoAg-I-BOA showed only slight anti-biofilm effects on test bacteria. Most notably, at all period of the clinical trial, NanoAg-IS-BOA showed a higher antibacterial activity than NanoAg-I-BOA.

CONCLUSION

Based on the novel data that presented here, the NanoAg-IS-BOA had strong antimicrobial activity in the planktonic phase and subsequent biofilm formation of the cariogenic bacteria.

CLINICAL SIGNIFICANCE

Wearing of NanoAg-IS-BOA has the potential to minimize dental plaque formation and caries during orthodontic treatment.

Risk factors for urinary catheter associated bloodstream infection

OBJECTIVES

Urinary catheter associated bloodstream infection (UCABSI) causes significant morbidity, mortality and healthcare costs. We aimed to define the risk factors for UCABSI.

METHODS

A case-control study was conducted at two Australian tertiary hospitals. Patients with urinary source bloodstream infection associated with an indwelling urinary catheter (IDC) were compared to controls with an IDC who did not develop urinary source bloodstream infection.

RESULTS

There were 491 controls and 67 cases included in the analysis. Independent statistically significant risk factors for the development of UCABSI included insertion of the catheter in operating theatre, chronic kidney disease, age-adjusted Charlson comorbidity index, accurate urinary measurements as reason for IDC insertion and dementia. IDCs were inserted for valid reasons in nearly all patients, however an appropriate indication at 48 h post-insertion was found in only 44% of patients. Initial empiric antibiotics were deemed inappropriate in 23 patients (34%).

CONCLUSION

To our knowledge, this is the first study to look specifically at the risk factors for bloodstream infection in urinary catheterised patients. Several risk factors were identified. IDC management and empiric management of UCABSI could be improved and is likely to result in a decreased incidence of infection and its complications.