In vitro comparison of efficacy of catheter locks in the treatment of catheter related blood stream infection

In vitro comparison of the effectiveness of various antimicrobial locks with taurolidine in the treatment and prevention of catheter-related bloodstream infections in patients receiving parenteral nutrition

OBJECTIVES

To evaluate the effectiveness of various taurolidine solutions in the prevention and treatment of catheter-related bloodstream infections (CRBSIs) caused by the entire spectrum of microbes in patients receiving parenteral nutrition in a shorter period of time.

METHODS

The in vitro method was used to test for eradication of biofilm. Different locks were used: TauroSept (2%), TauroLock (1.35%), TauroLock half concentration, and 3.5% taurolidine and tested on Staphylococcus (S.) epidermidis, S. aureus, S. hominis, methicillin-resistant S. aureus (MRSA), Pseudomonas (P.) aeruginosa (PSAE), multidrug-resistant P. aeruginosa (MR PSAE), vancomycin-resistant enterococci, Klebsiella pneumoniae producing carbapenemase (KPC), Klebsiella pneumoniae producing extended-spectrum beta-lactamase (KLPN ESBL), Candida (C.) albicans, and C. glabrata. Broviac catheters were incubated for growth of each organism and then incubated in lock solutions. Colony forming units (CFUs) were then counted after 30 min, 60 min, and 120 min of incubation.

RESULTS

A statistically significant decrease in CFUs was observed after 30 min of taurolidine exposure for S. hominis, PSAE, KLPN ESBL, KLPN KPC, C. albicans, and C. glabrata; after 60 min of exposure for S. epidermidis, PSAE, MR PSAE, KLPN ESBL, KPC, C. albicans, and C. glabrata; and after 120 min of exposure for S. epidermidis, S. hominis, S. aureus, PSAE, MR PSAE, KLPN ESBL, KPC, C. albicans, C. glabrata.

CONCLUSIONS

The application of taurolidine is effective in the treatment of CRBSIs. Taurolidine proved to be more effective against Gram-negative microorganisms during a 30-min exposure. Using 0.675% taurolidine is still effective. To achieve the required antimicrobial effect, the catheter must be sanitized for at least 2 h.

Reevaluation of lock solutions for Central venous catheters in hemodialysis: a narrative review

BACKGROUND

A significant proportion of incident and prevalent hemodialysis patients have central venous catheters for vascular access. No consensus is available on the prevention of catheter dysfunction or catheter-related bloodstream infections in patients undergoing hemodialysis by means of catheter lock solutions.

METHOD

We reviewed the effects of single and combined anticoagulants with antibacterial catheter lock solutions or other antimicrobials for the prevention of thrombosis or infections in hemodialysis patients. Relative risks with 95% confidence intervals for trials of the same type of catheter locking solution were pooled.

SOURCES OF INFORMATION

We included original research articles in English from PubMed, EMBASE, SpringerLink, Elsevier and Ovid using the search terms 'hemodialysis,' 'central venous catheter,' 'locking solution,' 'UFH,' 'low molecular weight heparin,' 'EDTA,' 'citrate,' 'rt-PA,' 'urokinase,' 'gentamicin,' 'vancomycin', 'taurolidine,' 'sodium bicarbonate,' 'hypertonic saline' and 'ethanol' and 'catheter'.

FINDINGS

Low-dose heparin lock solution (< 5000 U/ml) can efficiently achieve anticoagulation and will not increase the risk of bleeding. Low-concentration citrate (< 5%) combined with rt-PA can effectively prevent catheter infection and dysfunction. Catheter-related infections may be minimized by choosing the appropriate antibiotic and dose.

LIMITATIONS

There is a lack of follow-up validation data for LMWH, EDTA, taurolidine, sodium bicarbonate, ethanol, and other lock solutions.

IMPLICATIONS

Since catheterization is common in hemodialysis units, studies on long-term treatment and preventative strategies for catheter dysfunction and catheter-related infection are warranted.

Comparative effect of seven prophylactic locks to prevent biofilm biomass and viability in intravenous catheters

BACKGROUND

Patients requiring long-term intravenous access are at risk of intraluminal catheter bloodstream infection. 'Prophylactic' locks aim to limit this risk but there is uncertainty regarding the most effective lock.

OBJECTIVES

To develop a novel technique intended to replicate clinical procedures to compare the effectiveness of various 'prophylactic' locks against biofilm biomass ('biomass') formation and biofilm viability ('viability') of Escherichia coli and Staphylococcus epidermidis in intravenous catheters.

METHODS

For 10 consecutive days 106 cfu/mL E. coli NCTC 10418 and S. epidermidis ATCC 12228 were separately cultured in single lumen 9.6 French silicone tunnelled and cuffed catheters. These were flushed with 0.9% w/v sodium chloride using a push-pause technique before and after instillation of seven 'prophylactic' locks (water, ethanol, sodium chloride, heparinized sodium chloride, citrate, taurolidine plus citrate, and taurolidine; each in triplicate) for 6 h daily. Intraluminal 'biomass' and 'viability' were quantified using crystal violet staining and flush culture, respectively.

RESULTS

The reduction of 'biomass' and 'viability' depended on both agent and species. Citrate was least effective against E. coli 'viability' and 'biomass' but most effective against S. epidermidis 'viability', and taurolidine was most effective against E. coli 'biomass' and 'viability' but least effective against S. epidermidis 'viability'. 'Biomass' and 'viability' were significantly correlated in E. coli between (r = 0.997, P < 0.001) and within (r = 0.754, P = 0.001) interventions, but not in S. epidermidis.

CONCLUSIONS

A novel technique found the effect of 'prophylactic' agents in reducing 'biomass' and 'viability' varied by species. The choice of agent depends on the most likely infecting organism.

Pathogenesis and Clinical Relevance of Candida Biofilms in Vulvovaginal Candidiasis

The ability of Candida spp. to form biofilms is crucial for its pathogenicity, and thus, it should be considered an important virulence factor in vulvovaginal candidiasis (VVC) and recurrent VVC (RVVC). Its ability to generate biofilms is multifactorial and is generally believed to depend on the site of infection, species and strain involved, and the microenvironment in which the infection develops. Therefore, both cell surface proteins, such as Hwp1, Als1, and Als2, and the cell wall-related protein, Sun41, play a critical role in the adhesion and virulence of the biofilm. Immunological and pharmacological approaches have identified the NLRP3 inflammasome as a crucial molecular factor contributing to host immunopathology. In this context, we have earlier shown that Candida albicans associated with hyphae-secreted aspartyl proteinases (specifically SAP4-6) contribute to the immunopathology of the disease. Transcriptome profiling has revealed that non-coding transcripts regulate protein synthesis post-transcriptionally, which is important for the growth of Candida spp. Other studies have employed RNA sequencing to identify differences in the 1,245 Candida genes involved in surface and invasive cellular metabolism regulation. In vitro systems allow the simultaneous processing of a large number of samples, making them an ideal screening technique for estimating various physicochemical parameters, testing the activity of antimicrobial agents, and analyzing genes involved in biofilm formation and regulation (in situ) in specific strains. Murine VVC models are used to study C. albicans infection, especially in trials of novel treatments and to understand the cause(s) for resistance to conventional therapeutics. This review on the clinical relevance of Candida biofilms in VVC focuses on important advances in its genomics, transcriptomics, and proteomics. Moreover, recent experiments on the influence of biofilm formation on VVC or RVVC pathogenesis in laboratory animals have been discussed. A clear elucidation of one of the pathogenesis mechanisms employed by Candida biofilms in vulvovaginal candidiasis and its applications in clinical practice represents the most significant contribution of this manuscript.

Surface modification strategies for hemodialysis catheters to prevent catheter-related infections: A review

Insertion of a central venous catheter is one of the most common invasive procedures applied in hemodialysis therapy for end-stage renal disease. The most important complication of a central venous catheter is catheter-related infections that increase hospitalization and duration of intensive care unit stay, cost of treatment, mortality, and morbidity rates. Pathogenic microorganisms, such as, bacteria and fungi, enter the body from the catheter insertion site and the surface of the catheter can become colonized. The exopolysaccharide-based biofilms from bacterial colonies on the surface are the main challenge in the treatment of infections. Catheter lock solutions and systemic antibiotic treatment, which are commonly used in the treatment of hemodialysis catheter-related infections, are insufficient to prevent and terminate the infections and eventually the catheter needs to be replaced. The inadequacy of these approaches in termination and prevention of infection revealed the necessity of coating of hemodialysis catheters with bactericidal and/or antiadhesive agents. Silver compounds and nanoparticles, anticoagulants (e.g., heparin), antibiotics (e.g., gentamicin and chlorhexidine) are some of the agents used for this purpose. The effectiveness of few commercial hemodialysis catheters that were coated with antibacterial agents has been tested in clinical trials against catheter-related infections of pathogenic bacteria, such as Staphylococcus aureus and Staphylococcus epidermidis with promising results. Novel biomedical materials and engineering techniques, such as, surface micro/nano patterning and the conjugation of antimicrobial peptides, enzymes, metallic cations, and hydrophilic polymers (e.g., poly [ethylene glycol]) on the surface, has been suggested recently.

Antimicrobial Locks in Patients Receiving Home Parenteral Nutrition

Catheter-related bloodstream infection (CRBSI) is one of the most common and potentially fatal complications in patients receiving home parenteral nutrition (HPN). In order to prevent permanent venous access loss, catheter locking with an antimicrobial solution has received significant interest and is often a favored approach as part of the treatment of CRBSI, but mainly for its prevention. Several agents have been used for treating and preventing CRBSI, for instance antibiotics, antiseptics (ethanol, taurolidine) and, historically, anticoagulants such as heparin. Nonetheless, current guidelines do not provide clear guidance on the use of catheter locks. Therefore, this review aims to provide a better understanding of the current use of antimicrobial locking in patients on HPN as well as reviewing the available data on novel compounds. Despite the fact that our current knowledge on catheter locking is still hampered by several gaps, taurolidine and ethanol solutions seem promising for prevention and potentially, but not proven, treatment of CRBSI. Additional studies are warranted to further characterize the efficacy and safety of these agents.

Candida spp./Bacteria Mixed Biofilms

The ability to form biofilms is a common feature of microorganisms, such as bacteria or fungi. These consortiums can colonize a variety of surfaces, such as host tissues, dentures, and catheters, resulting in infections highly resistant to drugs, when compared with their planktonic counterparts. This refractory effect is particularly critical in polymicrobial biofilms involving both fungi and bacteria. This review emphasizes Candida spp.-bacteria biofilms, the epidemiology of this community, the challenges in the eradication of such biofilms, and the most relevant treatments.