Antimicrobial lock solutions for preventing catheter-related infections in haemodialysis

Antibiotic lock solutions as adjunct therapy for catheter-related blood stream infections in pediatric hemodialysis patients

The predominant use of intravenous catheters as primary access type in the pediatric hemodialysis population is associated with an increased risk of catheter related blood stream infections. While strict adherence to catheter placement and long-term care guidelines have helped to decrease the incidence of these infections, blood stream infections remain an infection burden in pediatric patients with long term hemodialysis catheters. The formation of biofilms on the surfaces of these catheters has been shown to be a source of microbes causing blood stream infections. One of the strategies for preventing bacterial colonization, inhibiting microbial multiplication, and suppressing the seeding of these microbes from biofilms upon maturation, has been the use of antibiotic-based lock solutions in-between dialysis treatments. Although clinical guidelines for the use of antibiotic lock solutions are yet to be developed, available evidence suggests a beneficial role of antibiotic lock solutions in the management of catheter related blood stream infections. Additionally, a clear understanding of how biofilms are formed and their role in the pathogenesis of catheter related bloodstream infection will facilitate the development of solutions that can prevent biofilm formation and inhibit their multiplication, maturation and seeding into the bloodstream.

In Vivo Effectiveness of Several Antimicrobial Locks To Eradicate Intravascular Catheter Coagulase-Negative Staphylococci Biofilms

Tunneled central venous catheter (TCVC) related infection remains a challenge in the care of hemodialysis patients. We aimed to determine the best antimicrobial lock therapy (ALT) to eradicate coagulase-negative staphylococci (CoNS) biofilms. We studied the colonization status of the catheter every 30 days by quantitative blood cultures (QBC) drawn through all catheter lumens. Those patients with a significant culture (i.e.,100 to 1,000 CFU/mL) of a CoNS were classified as patients with a high risk of developing catheter-related bloodstream infections (CRBSI). They were assigned to receive daptomycin, vancomycin, teicoplanin lock solution, or the standard of care (SoC) (i.e., heparin lock). The primary endpoint was to compare eradication ability (i.e., negative QBC for 30 days after ending ALT) rates between different locks and the SoC. A second objective was to analyze the correlation between ALT exposure and isolation of CoNS with antimicrobial resistance. Daptomycin lock was associated with a significant higher eradication success than with the SoC: 85% versus 30% (relative risk [RR] = 14, 95% confidence interval [CI] = 2.4 - 82.7); followed by teicoplanin locks with a 83.3% success (RR = 11.7; 95% CI = 2 - 70.2). We observed CoNs isolates with a higher teicoplanin MIC in patients with repeated teicoplanin locks exposure (coefficient = 0.3; 95% CI = 0.11 - 0.47). However, teicoplanin MICs decreased in patients treated with vancomycin locks (coefficient = -0.56; 95% CI = -0.85 - -0.02). Methicillin-resistance decreased with accumulative ALT (RR = 0.82; 95% CI = 0.69 - 0.98). In this study, daptomycin locks achieve the highest eradication rate of CoNS from hemodialysis catheters in vivo.

Interventions for treating catheter-related bloodstream infections in people receiving maintenance haemodialysis

BACKGROUND

Patients with kidney failure require vascular access to receive maintenance haemodialysis (HD), which can be achieved by an arteriovenous fistula or a central venous catheter (CVC). CVC use is related to frequent complications such as venous stenosis and infection. Venous stenosis occurs mainly due to trauma caused by the entrance of the catheter into the venous lumen and repeated contact with the vein wall.  A biofilm, a colony of irreversible adherent and self-sufficient micro-organisms embedded in a self-produced matrix of exopolysaccharides, is associated with the development of infections in patients with indwelling catheters. Despite its clinical relevance, the treatment of catheter-related bloodstream infections (CRBSIs) in patients receiving maintenance HD remains controversial, especially regarding catheter management. Antibiotic lock solutions may sterilise the catheter, treat the infection and prevent unnecessary catheter procedures. However, such treatment may also lead to antibiotic resistance or even clinical worsening in certain more virulent pathogens. Catheter removal and delayed replacement may remove the source of infection, improving infectious outcomes, but this approach may also increase vascular access stenosis, thrombosis or both, or even central vein access failure. Catheter guidewire exchange attempts to remove the source of infection while maintaining access to the same vein and, therefore, may improve clinical outcomes and preserve central veins for future access.

OBJECTIVES

To assess the benefits and harms of different interventions for CRBSI treatment in patients receiving maintenance HD through a permanent CVC, such as systemic antibiotics alone or systemic antibiotics combined with either lock solutions or catheter guidewire exchange or catheter replacement.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 21 December 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) and quasi-RCTs evaluating the management of CRBSI in permanent CVCs in people receiving maintenance HD.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, assessed their risk of bias, and performed data extraction. Results were expressed as risk ratios (RR) or hazard ratios (HR) for dichotomous outcomes and mean difference (MD) for continuous outcomes, with their 95% confidence intervals (CI). The certainty of the evidence was assessed using GRADE.

MAIN RESULTS

We identified two RCTs and one quasi-RCT that enrolled 760 participants addressing the treatment of CRBSIs in people (children and adults) receiving maintenance HD through CVC. No two studies compared the same interventions. The quasi-RCT compared two different lock solutions (tissue plasminogen activator (TPA) and heparin) with concurrent systemic antibiotics. One RCT compared systemic antibiotics alone and in association with an ethanol lock solution, and the other compared systemic antibiotics with different catheter management strategies (guidewire exchange versus removal and replacement). The overall certainty of the evidence was downgraded due to the small number of participants, high risk of bias in many domains, especially randomisation, allocation, and other sources of bias, and missing outcome data. It is uncertain whether an ethanol lock solution used with concurrent systemic antibiotics improved CRBSI eradication compared to systemic antibiotics alone (RR 1.61, 95% CI 1.16 to 2.23) because the certainty of this evidence is very low. There were no reported differences between the effects of TPA and heparin lock solutions on cure rates (RR 0.92, 95% CI 0.74 to 1.15) or between catheter guidewire exchange versus catheter removal with delayed replacement, expressed as catheter infection-free survival (HR 0.88, 95% CI 0.43 to 1.79). To date, no results are available comparing other interventions. Outcomes such as venous stenosis and/or thrombosis, antibiotic resistance, death, and adverse events were not reported.

AUTHORS' CONCLUSIONS

Currently, there is no available high certainty evidence to support one treatment over another for CRBSIs. The benefit of using ethanol lock treatment in combination with systemic antibiotics compared to systemic antibiotics alone for CRBSIs in patients receiving maintenance HD remains uncertain due to the very low certainty of the evidence. Hence, further RCTs to identify the benefits and harms of CRBSI treatment options are needed. Future studies should unify CRBSI and cure definitions and improve methodological design.

Nitric Oxide-Releasing Lock Solution for the Prevention of Catheter-Related Infection and Thrombosis

Although frequently used, venous catheters are often associated with serious complications such as infection and thrombosis. Lock solution therapies are clinically used to deter these issues but generally address only infection or thrombosis with limited success. Here, we report the development of a dual-functional lock therapy using nitric oxide (NO) donor molecule, S-nitrosoglutathione (GSNO). NO is a potent, broad-spectrum antimicrobial agent that also temporarily inhibits platelet activation, preventing thrombosis. Furthermore, NO has antibiofilm actions, an ability that traditional antibiotic lock solutions lack, thus limiting their efficacy. In this work, different concentrations of GSNO were characterized via NO analysis to determine a range of NO-releasing lock solution (NOreLS) concentrations to investigate and to demonstrate prolonged potential efficacy. Tested against clinically used vancomycin and gentamicin lock solutions, GSNO-based NOreLS repeatedly outperformed in models of different stages of catheter infections. NOreLS also prevented clot formation when exposed to whole blood, showing increased efficacy compared to a heparin lock solution. Moreover, NOreLS was demonstrated to be biocompatible via hemolysis and cytotoxicity assays. NOreLS has excellent potential for safely and effectively preventing infection and thrombosis related to catheter usage.

A Glance at Antimicrobial Strategies to Prevent Catheter-Associated Medical Infections

Urinary and intravascular catheters are two of the most used invasive medical devices; however, microbial colonization of catheter surfaces is responsible for most healthcare-associated infections (HAIs). Several antimicrobial-coated catheters are available, but recurrent antibiotic therapy can decrease their potential activity against resistant bacterial strains. The aim of this Review is to question the actual effectiveness of currently used (coated) catheters and describe the progress and promise of alternative antimicrobial coatings. Different strategies have been reviewed with the common goal of preventing biofilm formation on catheters, including release-based approaches using antibiotics, antiseptics, nitric oxide, 5-fluorouracil, and silver as well as contact-killing approaches employing quaternary ammonium compounds, chitosan, antimicrobial peptides, and enzymes. All of these strategies have given proof of antimicrobial efficacy by modifying the physiology of pathogens or disrupting their structural integrity. The aim for synergistic approaches using multitarget processes and the combination of both antifouling and bactericidal properties holds potential for the near future. Despite intensive research in biofilm preventive strategies, laboratorial studies still present some limitations since experimental conditions usually are not the same and also differ from biological conditions encountered when the catheter is inserted in the human body. Consequently, in most cases, the efficacy data obtained from in vitro studies is not properly reflected in the clinical setting. Thus, further well-designed clinical trials and additional cytotoxicity studies are needed to prove the efficacy and safety of the developed antimicrobial strategies in the prevention of biofilm formation at catheter surfaces.

REDUcing the burden of dialysis Catheter ComplicaTIOns: a National approach (REDUCCTION) - design and baseline results

BACKGROUND

Patients with hemodialysis central venous catheters (HD CVCs) are susceptible to health care-associated infections, particularly hemodialysis catheter-related bloodstream infection (HD-CRBSI), which is associated with high mortality and health care costs. There have been few systematic attempts to reduce this burden and clinical practice remains highly variable. This manuscript will summarize the challenges in preventing HD-CRBSI and describe the methodology of the REDUcing the burden of dialysis Catheter ComplicaTIOns: a National approach (REDUCCTION) trial.

METHODS

The REDUCCTION trial is a stepped-wedge cluster randomized trial of a suite of clinical interventions aimed at reducing HD-CRBSI across Australia. It clusters the intervention at the renal-service level with implementation randomly timed across three tranches. The primary outcome is the effect of this intervention upon the rate of HD-CRBSI. Patients who receive an HD CVC at a participating renal service are eligible for inclusion. A customized data collection tool allows near-to-real-time reporting of the number of active catheters, total exposure to catheters over time, and rates of HD-CRBSI in each service. The interventions are centered around the insertion, maintenance, and removal of HD CVC, informed by the most current evidence at the time of design (mid-2018).

RESULTS

A total of 37 renal services are participating in the trial. Data collection is ongoing with results expected in the last quarter of 2020. The baseline phase of the study has collected provisional data on 5385 catheters in 3615 participants, representing 603,506 days of HD CVC exposure.

CONCLUSIONS

The REDUCCTION trial systematically measures the use of HD CVCs at a national level in Australia, accurately determines the rate of HD-CRBSI, and tests the effect of a multifaceted, evidence-based intervention upon the rate of HD-CRBSI. These results will have global relevance in nephrology and other specialties commonly using CVCs.

Minimising Blood Stream Infection: Developing New Materials for Intravascular Catheters

Catheter related blood stream infection is an ever present hazard for those patients requiring venous access and particularly for those requiring long term medication. The implementation of more rigorous care bundles and greater adherence to aseptic techniques have yielded substantial reductions in infection rates but the latter is still far from acceptable and continues to place a heavy burden on patients and healthcare providers. While advances in engineering design and the arrival of functional materials hold considerable promise for the development of a new generation of catheters, many challenges remain. The aim of this review is to identify the issues that presently impact catheter performance and provide a critical evaluation of the design considerations that are emerging in the pursuit of these new catheter systems.

Impact of locking solutions on conditioning biofilm formation in tunnelled haemodialysis catheters and inflammatory response activation

INTRODUCTION

The surface of tunnelled cuffed catheters provides an optimal environment for the development of biofilms, which have recently been described as conditioning films because of the presence of adherent biological materials. These biofilms are associated with infection and thrombosis and potentially increase patients' inflammatory response. These complications could be reduced by the use of locking solutions.

OBJECTIVE

To analyse biofilm formation, using confocal and electron microscopy, in tunnelled cuffed catheters locked with three different solutions and to determine the relationship between these solutions and inflammatory response.

STUDY DESIGN

This prospective study included 35 haemodialysis patients with tunnelled cuffed catheter removal for non-infection-related reasons. The participants were divided into three groups according to the lock solution used: (1) heparin 1: 5000 IU; (2) citrate 4%; and (3) taurolidine 1.35%, citrate 4% and heparin 500 IU (taurolock); in the latter group, 25,000 IU taurolidine-urokinase was used in the last weekly session. All tunnelled cuffed catheters were cultured, and the inner surface was evaluated with confocal and electron microscopy. The inflammatory profile of included patients was determined at tunnelled cuffed catheter removal.

RESULTS

There were no differences in clinical or demographic variables between the three subgroups. Biofilm thickness was lower in the taurolidine group than in the citrate 4% and heparin groups (28.85 ± 6.86 vs 49.99 ± 16.56 vs 56.2 ± 15.67 µm, respectively; p < 0.001), as was biofilm volume (1.01 ±1.18 vs 3.7 ± 2.15 vs 5.55 ±2.44, µm³, respectively; p < 0.001). The mean interleukin-6 value was 39%, which was 50% lower than in the citrate and heparin groups, but without significance differences.

CONCLUSION

Our results show that biofilms were found in all tunnelled cuffed catheters, but the thickness and volume were significantly lower in tunnelled cuffed catheters locked with taurolidine solution. Therefore, the type of locking solution used in tunnelled cuffed catheters should maintain tunnelled cuffed catheter sterility and prevent catheter-related bloodstream infections. No significant difference was observed in the inflammatory profile according to the type of locking solution.

Antimicrobial Lock Therapy in Clinical Practice: A Scoping Review Protocol

Our objective is to review the scientific literature on the use of antimicrobial lock therapy (ALT). To achieve this result, our scoping review will address the following seven key questions: 1) Who are the patients who will benefit from this technique? 2) What are the techniques utilized? 3) What are the settings in which the technique is performed? 4) When the technique is performed? 5) Why the technique is performed? 6) How the technique is performed? 7) In how much amount, of such technique performed? This review considers all studies published in full and in peer-reviewed journals, with no restrictions on language, on the year of publication and age of the participants. Both randomized controlled trials and observational studies will be included. This scoping review has been planned on a five-stage framework: 1. Identifying the review question; 2. identifying relevant studies; 3. study selection; 4. charting the data; 5. collating, summarizing, and reporting the results. It is conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines. The databases utilized will include MEDLINE via PubMed, EMBASE and Cochrane Central Register of Controlled Trials and Grey Literature. SCOPING REVIEW REGISTRATION: Open Science Framework https://osf.io/vphwm/.

Dialysis Catheter-related Bloodstream Infections in Patients Receiving Hemodialysis on an Emergency-only Basis: A Retrospective Cohort Analysis

BACKGROUND

An estimated 6500 undocumented immigrants with end-stage renal disease (ESRD) live in the United States. Those living in states that do not provide undocumented immigrants scheduled hemodialysis receive intermittent hemodialysis only when life-threatening conditions arise. Little is known about catheter-related bloodstream infections (CRBSIs) in this population.

METHODS

We conducted a retrospective cohort study of emergency-only hemodialysis patients in the Harris Health System in Houston, Texas, between January 2012 and December 2015. We assessed CRBSI risk factors including demographics, comorbidities, and duration and frequency of hemodialysis. We investigated the microbiologic etiology of these infections, rates of recurrent CRBSI, and associated morbidity and mortality.

RESULTS

The cohort included 329 patients; 90% were Hispanic, 60% had diabetes, and the average age was 51 years. A total of 101 CRBSIs occurred, with a rate of 0.84 infections per 1000 catheter-days. Cirrhosis and duration of hemodialysis during the study period were associated with increased risk of CRBSI. Seventeen CRBSIs were recurrent; infection with gram-positive bacteria predicted recurrence. Adherence to catheter-related infection guidelines was improved by infectious diseases consultation and associated with fewer recurrent infections. CRBSI was associated with prolonged hospitalization (mean, 15 days), composite complication rate of 8%, and a 4% mortality rate.

CONCLUSIONS

Patients receiving emergency-only hemodialysis via tunneled catheters have a high CRBSI rate compared with infection rates previously reported in patients receiving scheduled maintenance hemodialysis. Increased CRSBI risk likely contributes to the increased morbidity and mortality seen in ESRD patients receiving emergency-only hemodialysis.

Renal replacement therapy: a practical update

Acute kidney injury (AKI) is defined as an abrupt decrease in kidney function, with the most severe form requiring some method of renal replacement therapy (RRT). The use of RRT is required in 5-10% of critically ill patients who develop severe AKI. Renal replacement therapy can be provided as either intermittent hemodialysis or one of the various modes of continuous renal replacement therapy (CRRT), with CRRT potentially conferring an advantage with respect to renal recovery and dialysis independence. There is no difference in mortality when comparing low (< 25 mL·kg^-1·hr^-1) vs high (> 40 mL·kg^-1·hr^-1) RRT dosing. Continuous renal replacement therapy may be run in different modes of increasing complexity depending on a given patient's clinical needs. Regional citrate anticoagulation is recommended as the therapy of choice for the majority of critically ill patients requiring CRRT.

Central venous catheters: Indications, techniques, and complications

Central venous catheters (CVC) are commonplace in the management of critically ill patients and serve a variety of purposes. Venous access is important for the administration of fluid and medications as well as blood procurement needed for lab analyses. However, not every critically ill patient requires a CVC. This article highlights the key considerations, pitfalls and evidence-based practices regarding the use pediatric central venous catheters.

Non-Antibiotic Antimicrobial Catheter Lock Solutions in Patients on Home Parenteral Nutrition

Patients on home parenteral nutrition (HPN) are dependent on central venous access for long-term sustenance, and catheter-related bloodstream infections (CRBSIs) are a major cause of morbidity and mortality in this patient population. As such, there is much interest in finding new methods for preventing CRBSIs in patients on HPN. As it is thought that these infections are preceded by microbial colonization of the catheter, one approach is to use antimicrobial catheter lock solutions. Although antibiotic catheter lock solutions have been present for decades, their use has been mostly limited to the treatment of CRBSIs due to concern for promoting microbial resistance. Recently, however, with the advent of non-antibiotic antimicrobial catheter lock solutions, this approach is gaining popularity as a promising method to decrease rates of CRBSI in HPN patients.

Antimicrobial lock solutions for preventing catheter-related infections in haemodialysis

BACKGROUND

Patients undergoing haemodialysis (HD) through a central venous catheter (CVC) are exposed to several risks, being a catheter-related infection (CRI) and a CVC lumen thrombosis among the most serious. Standard of care regarding CVCs includes their sealing with heparin lock solutions to prevent catheter lumen thrombosis. Other lock solutions to prevent CRI, such as antimicrobial lock solutions, have proven useful with antibiotics solutions, but not as yet for non-antibiotic antimicrobial solutions. Furthermore, it is uncertain if these solutions have a negative effect on thrombosis incidence.

OBJECTIVES

To assess the efficacy and safety of antimicrobial (antibiotic, non-antibiotic, or both) catheter lock solutions for preventing CRI in participants undergoing HD with a CVC.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register up to 18 December 2017 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised or quasi-randomised control trials (RCTs) comparing antimicrobial (antibiotic and non-antibiotic) lock solutions to standard lock solutions, in participants using a CVC for HD, without language restriction.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for eligibility, and two additional authors assessed for risk of bias and extracted data. We expressed results as rate ratios (RR) per 1000 catheter-days or 1000 dialysis sessions with 95% confidence intervals (CI). Statistical analyses were performed using the random-effects model.

MAIN RESULTS

Thirty-nine studies, enrolling 4216 participants, were included in this review, however only 30 studies, involving 3392 participants, contained enough data to be meta-analysed. Risk of bias was low or unclear for most domains in the majority of the included studies.Studies compared antimicrobial lock solutions (antibiotic and non-antibiotic) to standard sealing solutions (usually heparin) of the CVC for HD. Fifteen studies used antibiotic lock solutions, 21 used non-antibiotic antimicrobial lock solutions, and 4 used both (antibiotic and non-antibiotic) lock solutions. Studies reported the incidence of CRI, catheter thrombosis, or both.Antimicrobial lock solutions probably reduces CRI per 1000 catheter-days (27 studies: RR 0.38, 95% CI 0.27 to 0.53; I² = 54%; low certainty evidence), however antimicrobial lock solutions probably makes little or no difference to the risk of thrombosis per 1000 catheter days (14 studies: RR 0.79, 95% CI 0.52 to 1.22; I² = 83%; very low certainty evidence). Subgroup analysis of antibiotic and the combination of both lock solutions showed that both probably reduced CRI per 1000 catheter-days (13 studies: RR 0.30, 95% CI: 0.22 to 0.42; I² = 47%) and risk of thrombosis per 1000 catheter-days (4 studies: RR 0.26, 95% CI: 0.14 to 0.49; I² = 0%), respectively. Non-antibiotic antimicrobial lock solutions probably reduced CRI per 1000 catheter-days for tunnelled CVC (9 studies: RR 0.60, 95% CI 0.40 to 0.91) but probably made little or no difference with non-tunnelled CVC (4 studies: RR 0.93, 95% CI 0.48 to 1.81). Subgroup analyses showed that antibiotic (5 studies: RR 0.76, 95% CI 0.42 to 1.38), non-antibiotic (8 studies: RR 0.85, 95% CI 0.44 to 1.66), and the combination of both lock solutions (3 studies: RR 0.63, 95% CI 0.22 to 1.81) made little or no difference to thrombosis per 1000 catheter-days compared to control lock solutions.

AUTHORS' CONCLUSIONS

Antibiotic antimicrobial and combined (antibiotic-non antibiotic) lock solutions decreased the incidence of CRI compared to control lock solutions, whereas non-antibiotic lock solutions reduce CRI only for tunnelled CVC. The effect on thrombosis incidence is uncertain for all antimicrobial lock solutions. Our confidence in the evidence is low and very low; therefore, better-designed studies are needed to confirm the efficacy and safety of antimicrobial lock solutions.