Preliminary results treating persistent central venous catheter infections with the antibiotic lock technique in pediatric patients

Comparison of amphotericin B lipid complex, deoxycholate amphotericin B, fluconazole, and anidulafungin activity against Candida albicans biofilm isolated from breakthrough candidemia

INTRODUCTION

Biofilm formation causes virulence and resistance in Candida albicans. However, little is known about breakthrough candidemia isolates. We evaluated the antifungal activity of fluconazole, anidulafungin, deoxycholate amphotericin B (dAMB), and amphotericin B lipid complex (ABLC) against biofilms of C. albicans isolated from patients with breakthrough candidemia.

METHODS

The present study used strains of C. albicans isolated from breakthrough and non-breakthrough candidemia patients (control group). The susceptibility of planktonic cells to amphotericin B, anidulafungin, and fluconazole was determined by broth microdilution. Antifungal activity in sessile cells was evaluated using the minimum biofilm eradication concentration (MBEC), metabolic activity was estimated by reducing MTT, and biomass was estimated using crystal violet retention.

RESULTS

The planktonic strains were susceptible to amphotericin B, anidulafungin, and fluconazole, with minimum inhibitory concentrations of 1, ≤0.03, and 2mg/L, respectively. However, fluconazole and anidulafungin did not exert an antifungal effect on biofilms. Additionally, dAMB and ABCL reduced the metabolic activity and biomass. However, eradication was only achieved using 16mg/L dAMB. C. albicans isolates of breakthrough candidemia exhibited strong biofilm production, and the in vitro activity of available therapeutic options was poor.

CONCLUSION

In the present study, only dAMB and ABCL exhibited antibiofilm effects against sessile breakthrough candidemia isolates.

Antifungal lock therapy: an eternal promise or an effective alternative therapeutic approach?

Each year, millions of central venous catheter insertions are performed in intensive care units worldwide. The usage of these indwelling devices is associated with a high risk of bacterial and fungal colonization, leading to the development of microbial consortia, namely biofilms. These sessile structures provide fungal cells with resistance to the majority of antifungals, environmental stress and host immune responses. Based on different guidelines, colonized/infected catheters should be removed and changed immediately in the case of Candida‐related central line infections. However, catheter replacement is not feasible for all patient populations. An alternative therapeutic approach may be antifungal lock therapy, which has received high interest, especially in the last decade. This review summarizes the published Candida‐related in vitro, in vivo data and case studies in terms of antifungal lock therapy. The number of clinical studies remains limited and further studies are needed for safe implementation of the antifungal lock therapy into clinical practice.

Efficacy of liposomal amphotericin B and anidulafungin using an antifungal lock technique (ALT) for catheter-related Candida albicans and Candida glabrata infections in an experimental model

Objective

The aims of this study were as follows. First, we sought to compare the in vitro susceptibility of liposomal amphotericin B (LAmB) and anidulafungin on Candida albicans and Candida glabrata biofilms growing on silicone discs. Second, we sought to compare the activity of LAmB versus anidulafungin for the treatment of experimental catheter-related C. albicans and C. glabrata infections with the antifungal lock technique in a rabbit model.

Methods

Two C. albicans and two C. glabrata clinical strains were used. The minimum biofilm eradication concentration for 90% eradication (MBEC₉₀) values were determined after 48h of treatment with LAmB and anidulafungin. Confocal microscopy was used to visualize the morphology and viability of yeasts growing in biofilms. Central venous catheters were inserted into New Zealand rabbits, which were inoculated of each strain of C. albicans and C. glabrata. Then, catheters were treated for 48h with saline or with antifungal lock technique using either LAmB (5mg/mL) or anidulafungin (3.33mg/mL).

Results

In vitro: anidulafungin showed greater activity than LAmB against C. albicans and C. glabrata strains. For C. albicans: MBEC₉₀ of anidulafungin versus LAmB: CA176, 0.03 vs. 128 mg/L; CA180, 0.5 vs. 64 mg/L. For C. glabrata: MBEC₉₀ of anidulafungin versus LAmB: CG171, 0.5 vs. 64 mg/L; CG334, 2 vs. 32 mg/L. In vivo: for C. albicans species, LAmB and anidulafungin achieved significant reductions relative to growth control of log₁₀ cfu recovered from the catheter tips (CA176: 3.6±0.3 log₁₀ CFU, p≤0.0001; CA180: 3.8±0.1 log₁₀ CFU, p≤0.01). For C. glabrata, anidulafungin lock therapy achieved significant reductions relative to the other treatments (CG171: 4.8 log₁₀ CFU, p≤0.0001; CG334: 5.1 log₁₀ CFU, p≤0.0001)

Conclusions

For the C. albicans strains, both LAmB and anidulafungin may be promising antifungal lock technique for long-term catheter-related infections; however, anidulafungin showed significantly higher activity than LAmB against the C. glabrata strains.

International experience with minocycline, EDTA and ethanol lock for salvaging of central line associated bloodstream infections

BACKGROUND

The use of long-term central venous catheters (CVCs) could lead to serious bloodstream infections. Removal of the infected CVC and reinsertion of a new CVC are not always feasible and alternative lock therapy may be considered. We conducted a multicenter trial to assess the efficacy and safety of the lock therapy.

METHODS

Between October 2013 and August 2014, we prospectively enrolled 20 patients with catheter-related bloodstream infections (CRBSIs) or central line-associated bloodstream infections (CLABSIs) in our sister institutions in three countries including Brazil, Lebanon, and Japan. The 20 patients who received M-EDTA-EtOH lock therapy were compared to 24 control patients who had their CVCs removed and a new CVC inserted.

RESULTS

Both groups had comparable clinical characteristics. In the lock therapy group, 95% of the patients had microbiological eradication within 96 h after starting lock therapy versus 83% of the patients in the control group (p = .36). In the lock group, the CVC was salvaged and retained for a median of 21 days (range 7-51) from the onset of bacteremia.

CONCLUSION

Our study suggests that M-EDTA-EtOH lock therapy may be an effective intervention to salvage long-term CVCs in the setting of CLABSI/CRBSI and hemodialysis cancer patients with limited vascular access.

Intracatheter Antifungal Lock Leading to Detrimental Complications

As peritoneal dialysis (PD)-related fungal infection is associated with a high mortality rate, the international guidelines recommend immediate removal of the PD catheter in conjunction with at least 2-weeks of antifungal treatment. Some authors have reported successful management of such cases without removing the PD catheter - by instilling an antifungal lock into the retained PD catheter. However, the use of antifungal locks has generally not been well accepted as the standard treatment for fungal peritonitis in PD patients. We report two cases where antifungal lock were performed in PD patients presented with PD-related fungal infection that not only had no effect on abating the infection but also causing paradoxical outcomes.

Role of Antibiotic Lock Therapy for the Treatment of Catheter-Related Bloodstream Infections

Catheter-related bloodstream infections are often difficult to treat because they are caused by organisms that embed themselves in a bio film layer on the catheter surface, resulting in an increased resistance to antimicrobial agents. Systemic antibiotics are usually administered but, although generally effective in eliminating circulating bacteria, they frequently fail to sterilize the line, leaving the patient at a continuing risk of complications or recurrence. A successful approach to managing these infections requires making an appropriate decision regarding whether the catheter should be removed or retained using antibiotic lock therapy; and choosing the type and duration of antimicrobial therapy based on the type of organism and its resistance pattern. Studies that have evaluated antibiotic lock therapy have varied in the types of antibiotics and concentrations used, the addition of heparin to the solutions, and dwell times in the catheter lumen. Guidelines from the Infectious Diseases Society of America include use of antibiotic lock therapy as a therapeutic option for intraluminal infections when the device is not removed and, although not routine, as prophylaxis for catheter-related infection in select patient populations. However, there are no published guidelines on the concentration of heparin or antibiotics that should be used, and minimal published data on the stability of heparin combinations with antibiotics. It is to be hoped that antibiotic locks will be subject to randomized controlled trials of sufficient power to confirm or refute their use.

Successful Clearance of Catheter-Related Bloodstream Infection by Antibiotic Lock Therapy Using Ampicillin

Objective:

To report a case in which ampicillin was used successfully as lock therapy for a central venous intravascular catheter and to discuss the implications of ampicillin used in this modality.

Case Summary:

A 14-month-old girl with a long-term central venous catheter acquired a polymicrobial (Escherichia coli and Enterococcus durans) bloodstream infection. The central venous catheter was suspected as the source for the bacteremia based on the timing and number of positive blood cultures in relation to therapy with antibiotics. Antibiotic sensitivity testing revealed ampicillin monotherapy to be an ideal choice to treat both organisms. A combination of systemic therapy via a temporary catheter and antibiotic lock therapy of the central venous catheter was then instituted using ampicillin without anticoagulants. The patient tolerated this therapy without complications, and follow-up cultures demonstrated effective clearance of the bacteria.

Discussion:

Antibiotic lock therapy has been shown to be useful in the treatment of catheter-related bloodstream infections. However, many antibiotics have yet to be tested with this modality. Ampicillin, which is frequently used in the treatment of Enterococcus and E. coli infections, has not previously been reported as a single agent for lock therapy.

Conclusions:

Ampicillin may be a useful agent with the relatively new modality of lock therapy for central venous catheters. Further studies are needed to demonstrate possible compatibility of this agent with anticoagulants, such as heparin, as well as its efficacy in treating catheter-related bloodstream infections.

The clinical importance of fungal biofilms

Fungal biofilms have become an increasingly important clinical problem. The widespread use of antibiotics, frequent use of indwelling medical devices, and a trend toward increased patient immunosuppression have resulted in a creation of opportunity for clinically important yeasts and molds to form biofilms. This review will discuss the diversity and importance of fungal biofilms in the context of clinical medicine, provide novel insights into the clinical management of fungal biofilm infection, present evidence why these structures are recalcitrant to antifungal therapy, and discuss how our knowledge and understanding may lead to novel therapeutic intervention.

Antifungal Lock Therapy with Liposomal Amphotericin B: A Prospective Trial

We conducted a prospective pilot study to evaluate the potential role of combined systemic antifungal and liposomal amphotericin B lock therapy in children with intestinal insufficiency with fungal catheter-related bloodstream infections whose central venous catheters had not been removed. Our results provide supportive evidence for the conduct of larger clinical trials to confirm the efficacy and safety of this approach.

The prevention, diagnosis and management of central venous line infections in children

With advancing paediatric healthcare, the use of central venous lines has become a fundamental part of management of neonates and children. Uses include haemodynamic monitoring and the delivery of lifesaving treatments such as intravenous fluids, blood products, antibiotics, chemotherapy, haemodialysis and total parenteral nutrition (TPN). Despite preventative measures, central venous catheter-related infections are common, with rates of 0.5-2.8/1000 catheter days in children and 0.6-2.5/1000 catheter days in neonates. Central line infections in children are associated with increased mortality, increased length of hospital and intensive care unit stay, treatment interruptions, and increased complications. Prevention is paramount, using a variety of measures including tunnelling of long-term devices, chlorhexidine antisepsis, maximum sterile barriers, aseptic non-touch technique, minimal line accessing, and evidence-based care bundles. Diagnosis of central line infections in children is challenging. Available samples are often limited to a single central line blood culture, as clinicians are reluctant to perform painful venepuncture on children with a central, pain-free, access device. With the advancing evidence basis for antibiotic lock therapy for treatment, paediatricians are pushing the boundaries of line retention if safe to do so, due to among other reasons, often limited venous access sites. This review evaluates the available paediatric studies on management of central venous line infections and refers to consensus guidelines such as those of the Infectious Diseases Society of America (IDSA).

The Role of Antifungals against Candida Biofilm in Catheter-Related Candidemia

Catheter-related bloodstream infection (C-RBSI) is one of the most frequent nosocomial infections. It is associated with high rates of morbidity and mortality. Candida spp. is the third most common cause of C-RBSI after coagulase-negative staphylococci and Staphylococcus aureus and is responsible for approximately 8% of episodes. The main cause of catheter-related candidemia is the ability of some Candida strains-mainly C. albicans and C. parapsilosis-to produce biofilms. Many in vitro and in vivo models have been designed to assess the activity of antifungal drugs against Candida biofilms. Echinocandins have proven to be the most active antifungal drugs. Potential options in situations where the catheter cannot be removed include the combination of systemic and lock antifungal therapy. However, well-designed and -executed clinical trials must be performed before firm recommendations can be issued.

Antibiotic lock therapy: review of technique and logistical challenges

Antibiotic lock therapy (ALT) for the prevention and treatment of catheter-related bloodstream infections is a simple strategy in theory, yet its real-world application may be delayed or avoided due to technical questions and/or logistical challenges. This review focuses on these latter aspects of ALT, including preparation information for a variety of antibiotic lock solutions (ie, aminoglycosides, beta-lactams, fluoroquinolones, folate antagonists, glycopeptides, glycylcyclines, lipopeptides, oxazolidinones, polymyxins, and tetracyclines) and common clinical issues surrounding ALT administration. Detailed data regarding concentrations, additives, stability/compatibility, and dwell times are summarized. Logistical challenges such as lock preparation procedures, use of additives (eg, heparin, citrate, or ethylenediaminetetraacetic acid), timing of initiation and therapy duration, optimal dwell time and catheter accessibility, and risks of ALT are also described. Development of local protocols is recommended in order to avoid these potential barriers and encourage utilization of ALT where appropriate.

Central venous catheter-associated bloodstream infections in pediatric hematology-oncology patients and effectiveness of antimicrobial lock therapy

BACKGROUND

Central line-associated bloodstream infection (CLABSI) is a serious complication in hematology-oncology patients. This study aimed to analyze the prevalence of CLABSI and the effectiveness of antimicrobial lock therapy (ALT) in pediatric patients.

METHODS

BSIs of all pediatric hematology-oncology patients admitted to a children's hospital between January 2009 and December 2013 were reviewed. The United States National Healthcare Safety Network and Infectious Diseases Society of America guidelines were used to define CLABSI and catheter-related BSI (CRBSI). The incidence, laboratory and microbiology characteristics, poor outcome, and effectiveness of ALT were analyzed.

RESULTS

There were 246 cases of CLABSI in 146 patients (mean age, 10.0 years), including 66 (26.8%) cases of CRBSI. The incidence of CLABSI was 4.49/1000 catheter-days, and the infection was responsible for 32.9% of the complications these patients developed and 9.3% of contributable mortality. Patients with acute myeloid leukemia had the highest infection density (5.36/1000 patient-days). Enterobacteriaceae (40.2%) and coagulase-negative staphylococci (CoNS; 20.7%) were the predominant pathogens. In multivariate analysis, older age, male sex, elevated C-reactive protein, acute lymphoblastic leukemia, and candidemia were associated with poor outcome. The success rate of ALT was 58.6% (17/29) for the treatment of CoNS and 78.3% (29/37) for Enterobacteriaceae infections. Patients with candidemia (n = 18) had the highest mortality (33.4%) and catheter removal rate (66.7%). Chlorhexidine as the disinfectant decreased the 1-year CLABSI rate from 13.7/1000 to 8.4/1000 catheter-days (p = 0.02).

CONCLUSION

CoNS and Enterobacteriaceae are the predominant pathogens in CLABSI among pediatric hematology-oncology patients. ALT is effective and showed no significant side effect. New disinfection practice and infection control measures can decrease CLABSI.

Comparison of different doses of vancomycin andteicoplanin lock solutions in catheters colonized with Staphylococcus epidermidis: An in vitro, blinded, antibiotic lock study

BACKGROUND

The antibiotic lock (AL) technique is used for sterilization ofthe intraluminal surface of catheters. This technique consists of filling a catheter lumen with an antibiotic solution and allowing it to dwell for a time sufficient to sterilize the device. Glycopeptide antibiotics (vancomycin and teicoplanin) are commonly used agents for this purpose. But studies evaluating the different dosages of these antibiotics, their optimum concentrations, and duration in AL treatment are lacking.

OBJECTIVE

The aim of this study was to compare the efficacy of differentdoses of vancomycin/saline solution (VSS) and teicoplanin/saline solution (TSS) and to establish the optimal dosage and time needed to eliminate intraluminal methicillin-resistant Staphylococcus epidermidis colonization.

METHODS

This in vitro AL study was conducted at the Department of Infectious Diseases and Clinical Microbiology, Adnan Menderes University Medical Faculty, Aydin, Turkey. Catheters were divided into 2 groups those colonized with slime-forming S epidermidis, and those colonized with non-slime-forming S epidermidis. In each group, catheters were locked with VSS or TSS at 1-, 3-, and 5-mg/mL doses. Catheters instilled with saline solution were used as the control group. After 12 hours of incubation, the catheters were drained and filled with human plasma. Instillation of human plasma or AL solution was alternated every 12 hours to simulate clinical conditions. Every other day, catheters locked with each antibiotic dose or saline were cultured to determine colony count. These procedures were maintained until the catheters were sterile.

RESULTS

The baseline counts of slime-forming and non-slime-forming S epidermidisadhered to 1-cm segment catheters were 39 × 106 and 32 × 106 colony-forming units, respectively. The bacterial count was decreased significantly from baseline on the first day after the start of treatment (day 1) (P < 0.001). At the end of day 7, all catheters treated with antibiotics were sterile. The de creases in bacterial count were statistically similar in catheters treated with all doses of VSS and TSS. Also, the decrease in intraluminal colonization was statistically similar in catheters colonized with slime-forming S epidermidis and non-slime-forming S epidermidis.

CONCLUSION

In this in vitro, blinded AL study, the efficacy of vancomycin and teicoplanin lock solutions were similar and sterilized the catheters in 7 days, suggesting that the 2 antibiotics might be selected for shorter durations compared with those currently recommended for AL treatment in catheter-related infections due to methicillin-resistant staphylococci.

Antibiotic-lock therapy: a clinical viewpoint

Antibiotic lock therapy (ALT) - instillation of high concentrations of anti-microbial agent with or without anti-coagulant into the lumen of central venous catheters - is considered a valid conservative treatment for catheter-related bloodstream infection (CRBSI) in patients highly dependent on maintaining the catheter. Results from randomized controlled studies have indicated that the effectiveness of ALT is moderate, but recent findings from experimental studies and observational case series point to considerable efficacy and safety of this therapy, which is usually associated with concomitant systemic treatment. In this article, the current knowledge about ALT for patients with CRBSI is reviewed and discussed, with emphasis on existing controversies and the results obtained according to the various uses of the catheters and the etiologies of infection.

Bench-to-bedside review: Challenges of diagnosis, care and prevention of central catheter-related bloodstream infections in children

Central venous catheters (CVCs) are indispensable in modern pediatric medicine. CVCs provide secure vascular access, but are associated with a risk of severe complications, in particular bloodstream infection. We provide a review of the recent literature about the diagnostic and therapeutic challenges of catheter-related bloodstream infection (CRBSI) in children and its prevention. Variations in blood sampling and limitations in blood culturing interfere with accurate and timely diagnosis of CRBSI. Although novel molecular testing methods appear promising in overcoming some of the present diagnostic limitations of conventional blood sampling in children, they still need to solidly prove their accuracy and reliability in clinical practice. Standardized practices of catheter insertion and care remain the cornerstone of CRBSI prevention although their implementation in daily practice may be difficult. Technology such as CVC impregnation or catheter locking with antimicrobial substances has been shown less effective than anticipated. Despite encouraging results in CRBSI prevention among adults, the goal of zero infection in children is still not in range. More high-quality research is needed in the field of prevention, accurate and reliable diagnostic measures and effective treatment of CRBSI in children.

Antibiotic and other lock treatments for tunnelled central venous catheter-related infections in children with cancer

BACKGROUND

The risk of developing a tunnelled central venous catheter (CVC)-related infection ranges between 0.1 and 2.3 per 1000 catheter days for children with cancer. These infections are difficult to treat with systemic antibiotics (salvage rate 24% - 66%) due to biofilm formation in the CVC. Lock treatments can achieve 100 - 1000 times higher concentrations locally without exposure to high systemic concentrations.

OBJECTIVES

Our objective was to investigate the efficacy of antibiotic and other lock treatments in the treatment of CVC-related infections in children with cancer compared to a control intervention. We also assessed adverse events of lock treatments.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, issue 3, 2011), MEDLINE/PubMed (1945 to August 2011) and EMBASE/Ovid (1980 to August 2011). In addition we searched reference lists from relevant articles and the conference proceedings of the International Society for Paediatric Oncology (SIOP) (from 2006 to 2010), American Society of Clinical Oncology (ASCO) (from 2006 to 2010), the Multinational Association of Supportive Care in Cancer (MASCC) (from 2006 to 2011), the American Society of Hematology (ASH) (from 2006 to 2010) and the International Society of Thrombosis and Haematology (ISTH) (from 2006 to 2011). We scanned the ISRCTN Register and the National Institute of Health Register for ongoing trials (www.controlled-trials.com) (August 2011).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing an antibiotic lock or other lock treatment (with or without concomitant systemic antibiotics) with a control intervention (other lock treatment with or without concomitant systemic antibiotics or systemic antibiotics alone) for the treatment of CVC-related infections in children with cancer. For the description of adverse events, cohort studies were also eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, extracted data and performed 'Risk of bias' assessments of included studies. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Two RCTs evaluated urokinase lock treatment with concomitant systemic antibiotics (n = 56) versus systemic antibiotics alone (n = 48), and one CCT evaluated ethanol lock treatment with concomitant systemic antibiotics (n = 15) versus systemic antibiotics alone (n = 13). No RCTs or CCTs evaluating antibiotic lock treatments were identified. All studies had methodological limitations and clinical heterogeneity between studies was present. We found no evidence of significant difference between ethanol or urokinase lock treatments with concomitant systemic antibiotics and systemic antibiotics alone regarding the number of participants cured, the number of recurrent CVC-related infections, the number of days until the first negative blood culture, the number of CVCs prematurely removed, ICU admission and sepsis. Not all studies were included in all analyses. No adverse events occurred in the five publications of cohort studies (one cohort was included in two publications) assessing this outcome; CVC malfunctioning occurred in three out of five publications of cohort studies assessing this outcome.

AUTHORS' CONCLUSIONS

No significant effect of urokinase or ethanol lock in addition to systemic antibiotics was found. However, this could be due to low power or a too-short follow-up. The cohort studies identified no adverse events; some cohort studies reported CVC malfunctioning. No RCTs or CCTs were published on antibiotic lock treatment alone. More well-designed RCTs are needed to further explore the effect of antibiotic or other lock treatments in the treatment of CVC-related infections in children with cancer.

Reducing central line infections in pediatric and neonatal patients

The stakes for the prevention of central line associated bloodstream infections (CLABSIs) have increased dramatically over the past decade. Over the past 10 years, the rate of CLABSI in the pediatric population has dropped markedly due to the significant investment in this initiative. Although there has been a substantial increase in studies on CLABSIs, difficulties in studying CLABSIs have limited the quality of the evidence produced. These difficulties include challenges in the sample size required to complete trials, pressure from external regulatory forces to reduce CLABSI rates, and challenges in defining CLABSIs. The definition of CLABSI is continuously being updated to improve the misclassification bias inherent in defining CLABSI. This is especially relevant given the stress placed on decreasing health-care-associated infections and the negative consequences associated if unsuccessful. In order to prevent CLABSIs, pediatric and neonatal intensive care units have formed bundles of basic evidenced-based strategies leading to effective reduction of CLABSIs. These basic bundles have been modified for spread to other nonintensive care areas, also yielding great results. However, additional therapies above the basic bundle have yielded mixed results, and more research is needed to understand the cost effectiveness of these therapies in the setting of decreasing CLABSI rates. As a goal, a "getting to zero" CLABSI rate should be set, but it may not be possible without significant resource allocation.

Evaluation and Management of Bacterial and Fungal Infections Occurring in Patients with a Hematological Malignancy: A 2011 Update

Patients with a hematological malignancy are a heterogeneous patient population who are afflicted with diseases that range from rapidly fatal acute leukemia to indolent lymphoma or chronic leukemia. Treatment options for these patients range from observation to hematopoietic stem cell transplantation (HSCT), but all patients are more susceptible to infection. The problem of infection is dynamic with continued shifts in pathogenic organisms and microbial susceptibilities, new treatment regimens that further diminish immune function, and patients receiving treatment who are now older and frailer. The classic patterns of immunodeficiency for patients with a hematological malignancy include: periods of profound neutropenia, increased iatrogenic risks (i.e., central vascular catheters), and cellular immune suppression that affects HSCT recipients, patients with lymphoid malignancies, and those receiving treatment with corticosteroids or agents like alemtuzumab [1–4]. Recent advances in antimicrobial drug development, new technology, clinical trial results, and further clinical experience have enhanced the database on which to make infection prophylaxis and treatment decisions. However, the practicing clinician must remember that the majority of basic infection management principles for patients who are neutropenic remain unchanged.

Antifungal lock therapy

The widespread use of intravascular devices, such as central venous and hemodialysis catheters, in the past 2 decades has paralleled the increasing incidence of catheter-related bloodstream infections (CR-BSIs). Candida albicans is the fourth leading cause of hospital-associated BSIs. The propensity of C. albicans to form biofilms on these catheters has made these infections difficult to treat due to multiple factors, including increased resistance to antifungal agents. Thus, curing CR-BSIs caused by Candida species usually requires catheter removal in addition to systemic antifungal therapy. Alternatively, antimicrobial lock therapy has received significant interest and shown promise as a strategy to treat CR-BSIs due to Candida species. The existing in vitro, animal, and patient data for treatment of Candida-related CR-BSIs are reviewed. The most promising antifungal lock therapy (AfLT) strategies include use of amphotericin, ethanol, or echinocandins. Clinical trials are needed to further define the safety and efficacy of AfLT.

Antifungal lock therapy

The widespread use of intravascular devices, such as central venous and hemodialysis catheters, in the past 2 decades has paralleled the increasing incidence of catheter-related bloodstream infections (CR-BSIs). Candida albicans is the fourth leading cause of hospital-associated BSIs. The propensity of C. albicans to form biofilms on these catheters has made these infections difficult to treat due to multiple factors, including increased resistance to antifungal agents. Thus, curing CR-BSIs caused by Candida species usually requires catheter removal in addition to systemic antifungal therapy. Alternatively, antimicrobial lock therapy has received significant interest and shown promise as a strategy to treat CR-BSIs due to Candida species. The existing in vitro, animal, and patient data for treatment of Candida-related CR-BSIs are reviewed. The most promising antifungal lock therapy (AfLT) strategies include use of amphotericin, ethanol, or echinocandins. Clinical trials are needed to further define the safety and efficacy of AfLT.

Short-dwell ethanol lock therapy in children is associated with increased clearance of central line-associated bloodstream infections

BACKGROUND

Central line-associated bloodstream infection (CLABSI) is a known complication of central line use. Salvage of infected central lines with ethanol lock therapy (ELT) with systemic antimicrobials may be an alternative treatment option in children.

METHODS

Retrospective review was performed in children with CLASBI who underwent short-dwell ELT (70% ethanol, 4- to 25-hour dwell times ≤3 days) with systemic antimicrobials from January 1, 2007 to July 15, 2009.

RESULTS

A total of 59 patients, aged 2 months to 19 years (mean ± SD = 6.3 ± 6.1 years) with 80 episodes of CLABSI were included. The CLABSI eradication rate was 86% (69/80 episodes; 95% confidence interval [CI] 78%, 94%), significantly greater than 50% (Z = 2.35, P < .05), the estimated clearance rate of CLABSI eradication using systemic antimicrobials alone. Overall central line retention was 78% (60/77 episodes, 95% CI 69%, 87%). ELT was well tolerated.

CONCLUSIONS

These findings suggest the potential benefit of short-dwell ELT combined with systemic antimicrobials in CLABSI treatment. Randomized controlled trials are needed.

Daptomycin antibiotic lock therapy in a rat model of staphylococcal central venous catheter biofilm infections

Antibiotic lock therapy (ALT) is an adjunctive procedure to prevent or treat central venous catheter infections, ensuing catheter-related bacteremia, and catheter-related metastatic infections. Daptomycin is a cyclic lipopeptide that is rapidly bactericidal against methicillin-susceptible and -resistant Staphylococcus aureus. The efficacies of daptomycin against central venous catheter biofilms, catheter-related bacteremia, and catheter-related metastatic infections were evaluated by adapting a previously reported central venous catheter biofilm model in rats. Combined daptomycin ALT and systemic dosing resulted in the clearance of an established in vivo S. aureus central venous catheter biofilm after just two daily ALT treatments (30 min with daptomycin at 5 mg/ml) with concurrent systemic daptomycin dosing (40 mg/kg of body weight/day subcutaneously [s.c.]; equivalent exposure of 6 mg/kg/day in people). Daptomycin ALT solutions formulated in either saline or lactated Ringer's solution were equally fast in eradicating established in vivo methicillin-resistant Staphylococcus epidermidis (MRSE) central venous catheter biofilms. However, the lactated Ringer's formulation was superior to that of saline in sustaining the bacterial clearance of treated central venous catheters (83% versus 50%). In MRSE-infected central venous catheter studies, 3 days of daptomycin or vancomycin ALT (18 h at 5 mg/ml) with systemic s.c. dosing (40 mg/kg/day daptomycin or 100 mg/kg/day vancomycin) was equally effective 1 week posttherapy in maintaining cleared central venous catheters (90% [n = 10] versus 100% [n = 8]). These results suggest that daptomycin ALT, along with systemic dosing, could be an effective treatment option for the prevention or eradication of staphylococcal central venous catheter biofilm infections, thereby reducing the occurrence of catheter-related bacteremia or catheter-related metastatic infections.

Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia. Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving. What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens. Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care-associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Executive Summary: Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer: 2010 Update by the Infectious Diseases Society of America

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia.

Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving.

What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens.

Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care–associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Catheter-related bloodstream infections: catheter management according to pathogen

Central-line access is an essential part of modern healthcare practice; however, catheter-related bloodstream infection is a major problem that causes substantial morbidity and mortality, and excess length of stay and cost. The risk of infection depends on the type of device, the site of insertion, the underlying conditions and the appropriate prevention measures taken during catheter insertion. Management of catheter-related bloodstream infection involves deciding on catheter removal, antimicrobial catheter lock solution and the type and duration of systemic antimicrobial therapy. Systemic antimicrobial use is essential but, although generally effective in controlling sepsis, it often fails to sterilise the line, increasing the incidence of complications or recurrence. The decision regarding whether the catheter should be removed or retained is therefore crucial. One of the major factors to be considered is the type of organism involved in the catheter-related infection. This review outlines the epidemiology, pathogenesis, diagnosis, microbiology and management of catheter-related infections, mainly focusing on the management of the intravascular device according to the pathogen.

Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection: 2009 Update by the Infectious Diseases Society of America

These updated guidelines replace the previous management guidelines published in 2001. The guidelines are intended for use by health care providers who care for patients who either have these infections or may be at risk for them.

[Stability: a factor to consider in antibiotic-lock solutions]

Antibiotic-lock therapy (ALT) has been related to a reduction in the need for catheter withdrawal in patients with catheter-related infection. The stability of the antimicrobial solutions used in ALT has not been sufficiently investigated. A systematic literature review was performed to identify articles including studies on the stability of ALT solutions. Nine studies fulfilled the inclusion criteria requiring specific drug determination techniques, and no apparent drug alterations were observed. The main microorganisms studied were Staphylococcus spp., Pseudomonas aeruginosa, and Klebsiella pneumoniae. The antibiotics included cefazolin, ceftazidime, ciprofloxacin, colistin, gentamicin, ticarcillin/clavulanate, and vancomycin in solution, administered alone or in combinations, with or without heparin. All solutions were fairly stable except for ciprofloxacin at a concentration of 10mg/mL. Few studies applied strict criteria to assess the stability of antibiotic solutions used in ALT; hence, the currently available data are limited. Therefore, it seems advisable to include appropriate stability studies in further research on the use of ALT.

The role of chelators in preventing biofilm formation and catheter-related bloodstream infections

PURPOSE OF REVIEW

As metallic cations are essential to microbial adherence, biofilm formation, and bacterial growth, efforts have been directed toward utilizing metal-binding chelators that have the capability of inhibiting bacterial growth by disrupting surface adherence and preventing biofilm production. This review focuses on recent advances in the role of chelators in biofilm disruption and prevention of catheter-related bloodstream infections.

RECENT FINDINGS

The most important factor in the pathogenesis of catheter-related bloodstream infections is the intraluminal colonization of the central venous catheters through the formation of bacterial biofilm matrix in which microbial organisms embed themselves and eventually become a source of catheter-related bloodstream infections. It has been demonstrated that high-affinity metal-binding chelators including ethylenediamine-tetraacetic acid and citrate have the capacity of inhibiting microbial growth by disrupting surface adherence and preventing biofilm production. Furthermore, ethylenediamine-tetraacetic acid and citrate have been clinically shown to be highly effective and outperform heparin in the prevention and treatment of catheter-related bloodstream infections when used as a component of antimicrobial catheter lock solutions.

SUMMARY

It is suggested that the addition of chelators such as ethylenediamine-tetraacetic acid and citrate to antimicrobial lock solutions provides an innovative and superior alternative to heparin lock solution in the prevention and treatment of catheter-related bloodstream infections.

Treatment of central venous catheter fungal infection using liposomal amphotericin-B lock therapy

The current standard of care for a fungal central venous catheter infection in a pediatric patient usually requires removal without any other feasible options. Although removal may reduce the rate of Candida-associated complications, literature reviews question whether the outcomes of removal substantiate this being the standard of care. We report 6 cases of central venous catheter fungal infections treated with liposomal amphotericin-B lock therapy. These cases consisted of 4 patients, 2 of whom received recurrent therapy. In 4 of these cases, there was successful eradication of the infectious fungal agent, allowing continued use of the catheter. A controlled study of antifungal lock therapy should be considered as a potential alternative to removal.

Vascular catheter-associated infections: a microbiological and therapeutic update

The increasing incidence of central venous catheter (CVC)-related infections can be ascribed to the wider indications to central venous catheterization, to the higher attention to this issue paid by clinicians and microbiologists, and to the patient population referred to hospitals, increasingly characterized by different degrees of immunosuppression and often in critical clinical conditions. This phenomenon implies a higher health care burden and higher related costs, as well as a significant attributable mortality, that varies however according to the pathogen involved. The microorganisms most frequently involved in CVC-related infections are coagulase-negative staphylococci, Staphylococcus aureus, aerobic Gram-negative bacilli, and Candida albicans. In the management of suspected or proven central venous catheter-related infections, several issues need to be addressed: the need to remove the device or the possibility of salvage, the immediate start of calculated antibiotic therapy or the possibility of waiting for results of microbiological diagnostics and proceeding to etiologically-guided therapy. The preferred conservative method is the "Antibiotic-Lock technique" (ALT), based on the endoluminal application of antibacterials at extremely high concentrations in situ for a period of time long enough to ensure bactericidal activity. On the other hand, immediate catheter removal and initiation of appropriate calculated therapy immediately after an adequate diagnostic work-up are strongly recommended in a clinical setting of severe sepsis or septic shock.

Fusidic acid and heparin lock solution for the prevention of catheter-related bloodstream infections in critically ill neonates: a retrospective study and a prospective, randomized trial

OBJECTIVE

Catheter-related bloodstream infections (CRBSIs) are one of the main morbidities in critically ill neonates. The objective of the present study was to assess the efficacy of a fusidic acid-heparin lock in the prevention of CRBSIs.

DESIGN

A preliminary retrospective study showed that staphylococcal infections were largely prevalent. We planned a prospective, randomized trial to ascertain whether fusidic acid and heparin lock of central venous catheters would reduce the incidence of CRBSIs.

SETTING

Level III neonatal intensive care unit.

PATIENTS

One hundred three neonates were enrolled and randomly assigned to a treatment group (n = 50) or control group (n = 53).

INTERVENTIONS

Fusidic acid (4 mg/mL) and heparin (10 IU/mL) lock in the treatment group.

MEASUREMENTS AND MAIN RESULTS

The treatment group showed significantly lower incidence of CRBSIs (6.6 vs. 24.9 per 1000 catheter days; p < .01; relative risk 0.28; 95% confidence interval 0.13-0.60). No staphylococcal infections occurred in the treatment group, while in the control group Staphylococcus remained the main agent of CRBSI. Cost analysis comparing the present study and for the treatment of CRBSIs proved that antibiotic lock is financially favorable.

CONCLUSIONS

Fusidic acid-heparin lock solution reduced the incidence of CRBSIs in our neonatal intensive care unit. However, we recommend basing antibiotic lock on local CRBSI epidemiology. With regard to fusidic acid, further and broader studies could be useful to confirm our results.

Optimal antimicrobial catheter lock solution, using different combinations of minocycline, EDTA, and 25-percent ethanol, rapidly eradicates organisms embedded in biofilm

Antimicrobial lock solutions may be needed to salvage indwelling catheters in patients requiring continuous intravenous therapy. We determined the activity of minocycline, EDTA, and 25% ethanol, alone or in combination, against methicillin-resistant Staphylococcus aureus and Candida parapsilosis catheter-related bloodstream infection strains in two established models of biofilm colonization. Biofilm-colonized catheter segments from a modified Robbins device and a silicone disk biofilm colonization model were exposed to these antimicrobial agents for 15 or 60 min, respectively. After exposure, segments were sonicated and cultured. To determine regrowth after incubation at 37 degrees C, following the brief exposure to the antimicrobial agents, an equal number of segments were washed, reincubated for 24 h, and then sonicated and cultured. The triple combination of minocycline-EDTA (M-EDTA) in 25% ethanol was the only antimicrobial lock solution that completely eradicated S. aureus and C. parapsilosis in biofilm of all segments tested in the two models, and it completely prevented regrowth. In addition, M-EDTA in 25% ethanol was significantly more effective in rapidly eradicating the growth or regrowth of methicillin-resistant S. aureus and C. parapsilosis biofilm colonization in the two models than the other solutions--minocycline, EDTA, M-EDTA, 25% ethanol, and EDTA in ethanol. We conclude that M-EDTA in 25% ethanol is highly effective at rapidly eradicating S. aureus and C. parapsilosis embedded in biofilm adhering to catheter segments.

Predictors and outcome of catheter-related bacteremia in children on chronic hemodialysis

Tunneled central venous catheters are often used in children on chronic hemodialysis. This study was done to evaluate the spectrum of catheter-related bacteremia (CRB) and to determine predictors of recurrent CRB in children on hemodialysis. Chart review was performed in 59 children from a pediatric dialysis unit with chronic, tunneled, cuffed hemodialysis catheters between January 1999 and December 2003. CRB was diagnosed in 48 of 59 (81%) patients. The incidence of CRB was 4.8/1,000 catheter days. Overall catheter survival (290+/-216 days) was significantly longer than infection-free catheter survival (210+/-167 days, p<0.05). Organisms isolated were gram-positive in 67%, gram-negative in 14%, and polymicrobial in 19%. Systemic antibiotics cleared CRB in 34% and an additional 23% cleared with the inclusion of antibiotic-heparin locks; 43% required catheter exchange. There was a significant likelihood of early catheter exchange with polymicrobial CRB (p<0.01). Catheter loss occurred from infection in 63%. Risk factors for CRB included young age (<10 years) and presence of human immunodeficiency virus (HIV) infection. Patients with >2 initial positive blood cultures (p<0.0001) had a significantly higher rate of recurrence after 6 weeks of initial treatment. In conclusion, CRB remains a major determinant of catheter loss. However, overall catheter survival is longer than infection-free catheter survival, suggesting that systemic antibiotics with antibiotic-heparin locks should be the initial step in the management of CRB and this approach may salvage some catheters.

Use of Vancomycin-Containing Lock or Flush Solutions for Prevention of Bloodstream Infection Associated with Central Venous Access Devices: A Meta-Analysis of Prospective, Randomized Trials

BACKGROUND

Prolonged exposure to central venous access devices carries significant risk of device-associated bloodstream infection (BSI), which is associated with morbidity, added health care costs, and attributable mortality. We aimed to determine the efficacy of vancomycin-heparin lock or flush solution in preventing BSI in patients being treated with long-term central venous intravascular devices (IVDs).

METHODS

We collected data from January 1966 to January 2006 from multiple computerized databases and compiled reference lists of identified articles. We identified prospective, randomized controlled trials comparing a vancomycin-heparin lock or flush solution with heparin alone for prevention of BSI associated with long-term central venous IVDs. Using a standardized form, we abstracted data regarding study quality, patient characteristics, and incidence of BSI.

RESULTS

Seven randomized, controlled trials involving a total of 463 patients being treated with IVDs met the inclusion criteria; 5 studies were conducted among patients with cancer, 1 among a critically ill neonatal population, and 1 among patients with cancer or who required parenteral nutrition. We could not detect publication bias. The summary risk ratio with a vancomycin heparin-lock solution for IVD-associated BSI was 0.49 (95% confidence interval [CI], 0.26-0.95; P = .03). Results of the test for heterogeneity were statistically significant; however, when a single study was removed from the analysis, heterogeneity was no longer present. Use of vancomycin as a true lock solution--instilling it for a defined period, rather than simply flushing it directly through the device--conferred a much greater benefit, with a risk ratio of 0.34 (95% CI, 0.12-0.98; P = .04). The 2 studies that performed prospective surveillance cultures to identify colonization or infection by vancomycin-resistant organisms did not find an increased risk.

CONCLUSIONS

Use of a vancomycin lock solution in high-risk patient populations being treated with long-term central IVDs reduces the risk of BSI. The use of an anti-infective lock solution warrants consideration for patients who require central access but who are at high risk of BSI, such as patients with malignancy or low-birthweight neonates.

Candida glabrata fungemia cured by antibiotic-lock therapy: case report and short review

Catheter removal is now the standard recommendation of catheter-related fungemia even when tunneled devices are used. However, in the clinical practice, this procedure is not always without risks. Antibiotic-lock technique can resolve many cases of catheter-related bacteraemia, but cure of catheter-related candidemia by this method has been attempted in very few instances, reviewed in this article. Herein, we report a case of non-complicated Candida glabrata fungemia related to a Hickman catheter used for parenteral nutrition, cured with intraluminal amphotericin B in addition to systemic therapy. This case demonstrates that 'antifungal-lock therapy' can be effectively used in selected cases of catheter-related candidemia.