Antibiotic-lock therapy for long-term intravascular catheter-related bacteraemia: results of an open, non-comparative study

Salvage strategy for long-term central venous catheter-associated Staphylococcus aureus infections in children: a multi-centre retrospective study in France

OBJECTIVES

Catheter removal is recommended in adults with Staphylococcus aureus central-line-associated bloodstream infection (CLABSI) but is controversial in children with long-term central venous catheters (LTCVC). We evaluated the occurrence of catheter salvage strategy (CSS) in children with S. aureus LTCVC-associated CLABSI and assessed determinants of CSS failure.

METHODS

We retrospectively included children (<18 years) with an LTCVC and hospitalized with S. aureus CLABSI in eight French tertiary-care hospitals (2010-2018). CSS was defined as an LTCVC left in place ≥72 h after initiating empiric antibiotic treatment for suspected bacteraemia. Characteristics of patients were reviewed, and multi-variable logistic regression was performed to identify factors associated with CSS failure (i.e., persistence, recurrence or complications of bacteraemia).

RESULTS

We included 273 episodes of S. aureus LTCVC-associated CLABSI. CSS was chosen in 194 out of 273 (71%) cases and failed in 74 of them (38%). The main type of CSS failure was the persistence of bacteraemia (39 of 74 cases, 53%). Factors independently associated with CSS failure were: history of catheter infection (adjusted odds ratio (aOR) 3.18, 95% confidence interval (CI) 1.38-7.36), CLABSI occurring on an implantable venous access device (aOR 7.61, 95% CI 1.98-29.20) when compared with tunnelled-cuffed CVC, polymicrobial CLABSI (aOR 3.45, 95% CI 1.25-9.50), and severe sepsis at the initial stage of infection (aOR 4.46, 95% CI 1.18-16.82).

CONCLUSIONS

CSS was frequently chosen in children with S. aureus LTCVC-associated CLABSI, and failure occurred in one-third of cases. The identified risk factors may help clinicians identify children at risk for CSS failure.

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 Vitro and In Vivo Antimicrobial Activity of Hypochlorous Acid against Drug-Resistant and Biofilm-Producing Strains

The aims of this study were as follows. First, we determined the antimicrobial efficacy of hypochlorous acid (HClO) against bacterial, fungal, and yeast strains growing planktonically and growing in biofilms. Second, we sought to compare the activity of the combination of daptomycin and HClO versus those of the antimicrobial agents alone for the treatment of experimental catheter-related Staphylococcus epidermidis infection (CRI) using the antibiotic lock technique (ALT) in a rabbit model. HClO was generated through direct electric current (DC) shots at determined amperages and times. For planktonic susceptibility studies, 1 to 3 DC shots of 2, 5, and 10 mA from 0 to 300 s were applied. A DC shot of 20 mA from 0 to 20 min was applied to biofilm-producing strains. Central venous catheters were inserted into New Zealand White rabbits, inoculated with an S. epidermidis strain, and treated with saline solution or ALT using daptomycin (50 mg/mL), HClO (20 mA for 45 min), or daptomycin plus HClO. One hundred percent of the planktonic bacterial, fungal, and yeast strains were killed by applying one DC shot of 2, 5, and 10 mA, respectively. One DC shot of 20 mA for 20 min was sufficient to eradicate 100% of the tested biofilm-producing strains. Daptomycin plus HClO lock therapy showed the highest activity for experimental CRI with S. epidermidis. HClO could be an effective strategy for treating infections caused by extensively drug-resistant or multidrug-resistant and biofilm-producing strains in medical devices and chronic wounds. The results of the ALT using daptomycin plus HClO may be promising. IMPORTANCE Currently, drug-resistant infections are increasing and there are fewer antibiotics available to treat them. Therefore, there is an urgent need to find new antibiotics and nonantimicrobial strategies to treat these infections. We present a new nonantibiotic strategy based on hypochlorous acid generation to treat long-term catheter-related and chronic wounds infections.

In vitro Activities of N-Acetyl Cysteine and Levofloxacin as a Catheter Lock Therapy against Catheter-Associated Infections

AIMS

Since management of catheter-associated infections, which are generally biofilm-based, is attempted in certain patients such as older and frail patients by using a catheter lock solution (CLS), we examined the combination of N-acetyl cysteine (NAC), an antibiofilm agent, and levofloxacin, a broad-spectrum antimicrobial agent, for this purpose.

METHODS AND RESULTS

Intravascular catheters were colonized with methicillin-resistant Staphylococcus epidermidis, levofloxacin-sensitive/methicillin-resistant S. aureus, levofloxacin-resistant/methicillin-resistant S. aureus, vancomycin-resistant Enterococcus, Escherichia coli, Klebsiella pneumoniae, or Pseudomonas aeruginosa and treated with a CLS containing normal saline, NAC, levofloxacin, or NAC plus levofloxacin (NACLEV) and then cultured to assess their antimicrobial activities. We also examined antibiofilm and antimicrobial activities of each CLS by scanning electron microscopy (SEM) and the mechanical integrity of catheters exposed to CLS. Treatment of colonized catheters with NACLEV-CLS significantly reduced colonization (P < 0.005) against all pathogens. SEM images also indicate reduction in colonization with NACLEV-CLS with considerable reduction in both visible bacteria and the associated biofilm. Mean tensile strength of catheters exposed to CLS was not significantly different compared to controls (P>0.05).

CONCLUSIONS

These in-vitro results suggest that NACLEV-CLS can significantly reduce all bacterial colonization and potentially help salvage infected catheters without affecting the catheter's mechanical integrity.

SIGNIFICANCE AND IMPACT OF STUDY

This study presents a novel CLS with a broad spectrum of antimicrobial activity against catheter-associated infections, particularly in long-term catheters.

EDTA and Taurolidine Affect Pseudomonas aeruginosa Virulence In Vitro-Impairment of Secretory Profile and Biofilm Production onto Peritoneal Dialysis Catheters

Peritoneal catheter-associated biofilm infection is reported to be the main cause of refractory peritonitis in peritoneal dialysis patients. The application of antimicrobial lock therapy, based on results on central venous catheters, may be a promising option for treatment of biofilm-harboring peritoneal catheters. This study investigated the effects of two lock solutions, EDTA and taurolidine, on an in vitro model of Pseudomonas aeruginosa biofilm-related peritoneal catheter infection. Silicone peritoneal catheters were incubated for 24 h with a bioluminescent strain of P. aeruginosa. Then, serial dilutions of taurolidine and/or EDTA were applied (for 24 h) once or twice onto the contaminated catheters, and P. aeruginosa viability/persistence were evaluated in real time up to 120 h using a Fluoroskan reader. On selected supernatants, high-performance liquid chromatography mass spectrometry (HPLC-MS) analysis was performed to measure the production of autoinducers (AI), phenazines, and pyocyianines. Taurolidine alone or in combination with EDTA caused a significant decrease of bacterial load and biofilm persistence on the contaminated catheters. The treatment did not lead to the sterilization of the devices, yet it resulted in a substantial destructuration of the catheter-associated P. aeruginosa biofilm. HPLC-MS analysis showed that the treatment of biofilm-harboring catheters with taurolidine and EDTA also affected the secretory activity of the pathogen. EDTA and taurolidine affect P. aeruginosa biofilm produced on peritoneal catheters and profoundly compromise the microbial secretory profile. Future studies are needed to establish whether such lock solutions can be used to render peritoneal catheter-related infections more susceptible to antibiotic treatment. IMPORTANCE An in vitro model allows studies on the mechanisms by which the lock solutions exert their antimicrobial effects on catheter-associated biofilm, thus providing a better understanding of the management of devise-associated infections.

Comparing success rates in central venous catheter salvage for catheter-related bloodstream infections in adult patients on home parenteral nutrition: a systematic review and meta-analysis

BACKGROUND

Catheter-related bloodstream infection (CRBSI) is a life-threatening complication of parenteral nutrition. Therefore, optimal management, ideally with catheter salvage, is required to maintain long-term venous access.

OBJECTIVES

We aimed to evaluate successful catheter salvage rates in patients on home parenteral nutrition (HPN).

METHODS

Studies were retrieved from medical databases, conference proceedings, and article reference lists. Data were collected relating to clinical outcomes of 3 treatments: systemic antibiotics, antimicrobial lock therapy (ALT), and catheter exchange. ORs and 95% CIs were calculated from a mixed logistic effects model.

RESULTS

From 10,036 identified publications, 28 met the inclusion criteria (22 cohort studies, 5 case-control studies, and 1 randomized clinical trial), resulting in a total of 4911 CRBSIs. To achieve successful catheter salvage, the addition of an antimicrobial lock solution was superior to systemic antibiotics alone (OR: 1.75; 95% CI: 1.21, 2.53; P = 0.003). Recurrence of infection was less common in studies that used ALT than in those that used systemic antibiotics alone (OR: 0.26; 95% CI: 0.11, 0.61; P = 0.002). The catheter exchange group was excluded from multilevel regression analysis because only 1 included study applied this treatment. Successful salvage rates were highest for coagulase-negative staphylococci, followed by Gram-negative rods and Staphylococcus aureus .

CONCLUSIONS

The addition of an antimicrobial lock solution seems beneficial for successful catheter salvage in HPN-dependent patients with a CRBSI. Future prospective randomized studies should identify the most effective and pathogen-specific strategy.This review was registered at www.crd.york.ac.uk/PROSPERO as CRD42018102959.

Analysis of risk factors of PICC-related bloodstream infection in newborns: implications for nursing care

Background

It is necessary to analyze the characteristics and risk factors of catheter-related bloodstream infection (CRBSI) in newborns with peripherally inserted central catheter (PICC).

Methods

Newborns undergoing PICC catheterization in the neonatal department of our hospital from January 1, 2020 to January 31, 2021 were included. The characteristics of newborns with and without CRBSI newborns were compared and analyzed. Logistic regression analyses were performed to evaluate the risk factors of CRBSI in newborns with PICC.

Results

Three hundred eighty-six newborns with PICC were included, of whom 41 newborns had the CRBSI, the incidence of CRBSI in newborns with PICC was 10.62%. There were significant differences regarding the birth weight, durations of PICC stay, 5-min Apgar score, site of PICC insertion of PICC between CRBSI and no CRBSI group (all P < 0.05), and there were no significant differences regarding the gender, gestational age, cesarean section, mechanical ventilation and length of hospital stay between CRBSI and no CRBSI group (all P > 0.05). Escherichia coli (26.08%) and Staphylococcus aureus (23.92%) were the most common CRBSI pathogens in newborns with PICC. Logistic regression analysis indicated that birth weight ≤ 1500 g (OR 1.923, 95% CI 1.135–2.629), durations of PICC stay ≥ 21 days (OR 2.077, 95% CI 1.024–3.431), 5-min Apgar score ≤ 7 (OR 2.198, 95% CI 1.135–3.414) and femoral vein insertion of PICC (OR 3.044, 95% CI 1.989–4.306) were the independent risk factors of CRBSI in neonates with PICC (all P < 0.05).

Conclusion

For newborns with low birth weight, longer durations of PICC stay and femoral vein PICC insertion, they may have higher risks of CRBSI, and medical staff should take targeted measures to reduce the development of CRBSI.

Can vancomycin lock therapy extend the retention time of infected long-term catheters?

We assessed the success rate of vancomycin catheter lock therapy (VLT) in combination with systemic antimicrobials in patients with staphylococcal catheter-related bloodstream infection (C-RBSI). Over a 6-year period, we retrospectively collected clinical and microbiological data from patients with long-term central venous catheters and staphylococcal C-RBSI who were treated with systemic antimicrobials and VLT. We then assessed the success rate of VLT based on two criteria: 1) catheter retention time> 3 months and 2) catheter in place until end of use. We found 217 staphylococcal C-RBSI episodes, 115 (53.0%) of which were managed with conservative therapy. Of these, 76 (66.1%) were treated with VLT (85.5% coagulase-negative staphylococci and 14.5% Staphylococcus aureus). The success rate of VLT was 42.1% with criterion 1 and 71.1% with criterion 2. We did not find statistically significant differences between success and failure in the majority of the clinical data recorded. We only found differences for crude mortality in criterion 1 and for parenteral nutrition in criterion 2. The success of catheter retention using VLT was moderate, reaching slightly more than 70% when the catheter was kept in place until the end of use.

Bactericidal and Antiproliferative Effects of Peripheral Parenteral Nutrition Solutions with Sodium Bisulfite on Pathogenic Microorganisms in Catheter Lumens

Catheter-related bloodstream infections (CRBSIs) due to pathogenic microorganisms pose a major threat to patients requiring parenteral nutrition (PN). Additives contained in medicines and foods have antiproliferative and bacteriostatic effects on pathogenic microorganisms. Therefore, PN solutions containing additives may also have an antibacterial effect. However, so far, there have been no reports on or observations of a PN solution with bactericidal activity. In this study, we assessed several nutrition solutions with antimicrobial activities and investigated their effects on pathogenic microorganisms colonizing catheter lumens. We selected the highly acidic Plas-Amino^® (PA), which contains a large amount of sodium bisulfite as a preservative and potentially has an antimicrobial effect. In this study, we used the following pathogenic bacteria as the main causatives of CRBSIs: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Serratia marcescens, Pseudomonas aeruginosa, and Candida albicans. We then created a catheter lumen microorganism contamination model and evaluated the antibacterial effect of PA; we found that all bacteria in the control group grew significantly in the catheter lumen in a time-dependent manner at 48 and 72 h. On the other hand, we demonstrated that PA has bactericidal effects on S. aureus, S. epidermidis, B. cereus, S. marcescens, and P. aeruginosa in the catheter lumen and confirmed that it has a remarkable antiproliferative effect on C. albicans. Hence, we concluded that highly acidic PN solutions that contain a preservative like sodium bisulfite have bactericidal and growth inhibition effects on microorganisms in the catheter lumens of patients with CRBSIs and patients with totally implantable central venous access devices, in whom it is difficult to remove the catheter.

High success rate in salvage of catheter-related bloodstream infections due to Staphylococcus aureus, on behalf of project group of Italian society of nephrology

BACKGROUND

Catheter-related bloodstream infections caused by Staphylococcus aureus represent one of the most fearful infections in chronic haemodialysis patients with tunnelled central venous catheters. Current guidelines suggest prompt catheter removal in patients with positive blood cultures for S. aureus. This manoeuvre requires inserting a new catheter into the same vein or another one and is not without its risks.

METHODS

A protocol based on early, prompt diagnosis and treatment has been utilized in our renal unit since 2012 in an attempt to salvage infected tunnelled central venous catheters. We prospectively observed 247 tunnelled central venous catheters in 173 haemodialysis patients involving 167,511 catheter days.

RESULTS

We identified 113 catheter-related bloodstream infections (0.67 episodes per 1000 days/tunnelled central venous catheter). Forty were caused by S. aureus, including 19 by methicillin-resistant S. aureus (79% saved) and 21 by methicillin-sensitive S. aureus (90% saved), of which 34 (85%) were treated successfully. Eight recurrences occurred and six (75%) were successfully treated. A greater than 12 h time to blood culture positivity for S. aureus was a good prognostic index for successful therapy and tunnelled central venous catheter rescue.

CONCLUSION

Our data lead us to believe that it is possible to successfully treat catheter-related bloodstream infection caused by S. aureus and to avoid removing the tunnelled central venous catheter in many more cases than what has been reported in the literature. On the third day, it is mandatory to decide whether to replace the tunnelled central venous catheter or to carry on with antibiotic therapy. Apyrexia and amelioration of laboratory parameters suggest continuing systemic and antibiotic lock therapy for no less than 4 weeks, otherwise, tunnelled central venous catheter removal is recommended.

Clinical profile and outcome of antibiotic lock therapy for bloodstream infections in pediatric hematology/oncology patients in a tertiary care hospital, Karachi, Pakistan

Background

Intravascular catheters are susceptible to infections, thus requiring catheter removal and leading to increased morbidity and costs. Antibiotic lock therapy (ALT) is a therapeutic technique that is used to salvage the catheter. The aim of this study was to evaluate the outcome of antibiotic lock therapy in bloodstream infections in pediatric hematology/oncology patients in a tertiary care hospital, Karachi.

Methods

A retrospective review was performed from January 2013 to December 2017 of pediatric hematology/oncology patients with bloodstream infections and who received ALT at Aga Khan University Hospital. All cases of polymicrobial infections, catheter removal, or malfunction before the completion of ALT were excluded. Descriptive analysis was carried out using SPSS version 20.

Results

A total of nine hematology/oncology patients were eligible. The catheter was salvaged in 7/9 (77.8%) children, and in 2/9 (22.2%) cases, catheter was removed because of persistent bacteremia. The most common organism isolated was Staphylococcus non-aureus species (33.3%). Relapse with a similar pathogen occurred in 2 (22.2%) patients and 2 (22.2%) of them developed an exit-site infection.

Conclusion

In our experience, in almost two thirds of the cases, the catheter was salvaged, but disappointingly, relapses were high when the infection was due to Staphylococcus spp. Although this is a small study, our results show that ALT can be a potential safe adjunctive strategy to treat catheter-related bloodstream infections (CRBSI). However, we need larger prospective studies to test the safety and efficacy of ALT to develop specific ALT recommendations and guidelines particularly in children.

Diagnosis and treatment of catheter-related bloodstream infection: Clinical guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology and (SEIMC) and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC)

Catheter-related bloodstream infections (CRBSI) constitute an important cause of hospital-acquired infection associated with morbidity, mortality, and cost. The aim of these guidelines is to provide updated recommendations for the diagnosis and management of CRBSI in adults. Prevention of CRBSI is excluded. Experts in the field were designated by the two participating Societies (the Spanish Society of Infectious Diseases and Clinical Microbiology and [SEIMC] and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units [SEMICYUC]). Short-term peripheral venous catheters, non-tunneled and long-term central venous catheters, tunneled catheters and hemodialysis catheters are covered by these guidelines. The panel identified 39 key topics that were formulated in accordance with the PICO format. The strength of the recommendations and quality of the evidence were graded in accordance with ESCMID guidelines. Recommendations are made for the diagnosis of CRBSI with and without catheter removal and of tunnel infection. The document establishes the clinical situations in which a conservative diagnosis of CRBSI (diagnosis without catheter removal) is feasible. Recommendations are also made regarding empirical therapy, pathogen-specific treatment (coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus spp., Gram-negative bacilli, and Candida spp.), antibiotic lock therapy, diagnosis and management of suppurative thrombophlebitis and local complications.

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.

Role of Lock Therapy for Long-Term Catheter-Related Infections by Multidrug-Resistant Bacteria

The management of long-term central venous catheter (LTCVC) infections by multidrug-resistant (MDR) bacteria in cancer patient is a challenge. The objectives of this study were to analyze outcomes in cancer patients with LTCVC-associated infection, identify risks for unfavorable outcomes, and determine the impact of MDR bacteria and antibiotic lock therapy (ALT) in managing such infections. We evaluated all LTCVC-associated infections treated between January 2009 and December 2016. Infections were reported in accordance with international guidelines for catheter-related infections. The outcome measures were 30-day mortality and treatment failure. We analyzed risk factors by Cox forward-stepwise regression. We identified 296 LTCVC-associated infections; 212 (71.6%) were classified as bloodstream infections (BSIs). The most common agent was Staphylococcus aureus Forty-six (21.7%) infections were due to MDR Gram-negative bacteria. ALT was used in 62 (29.2%) patients, with a 75.9% success rate. Risk factors identified for failure of the initial treatment were having a high sequential organ failure assessment (SOFA) score at diagnosis of infection and being in palliative care; introduction of ALT at the start of treatment was identified as a protective factor. Risk factors identified for 30-day mortality after LTCVC-associated infection were a high SOFA score at diagnosis, infection with MDR bacteria, and palliative care; introduction of ALT at the start of treatment, hematological malignancies, and adherence to an institutional protocol for the management of LTCVC-associated infection were identified as protective factors. Despite the high incidence of infection with MDR bacteria, ALT improves the outcome of LTCVC-associated infection in cancer patients.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Infection of totally implantable venous access devices: A review of the literature

Totally implantable venous access devices, or ports, are essential in the therapeutic management of patients who require long-term intermittent intravenous therapy. Totally implantable venous access devices guarantee safe infusion of chemotherapy, blood transfusion, parenteral nutrition, as well as repeated blood samples. Minimizing the need for frequent vascular access, totally implantable venous access devices also improve the patient's quality of life. Nonetheless, totally implantable venous access devices are not free from complications. Among those, infection is the most relevant, affecting patients' morbidity and mortality-both in the hospital or outpatient setting-and increasing healthcare costs. Knowledge of pathogenesis and risk factors of totally implantable venous access device-related infections is crucial to prevent this condition by adopting proper insertion bundles and maintenance bundles based on the best available evidence. Early diagnosis and prompt treatment of infection are of paramount importance. As a totally implantable venous access device-related infection occurs, device removal or a conservative approach should be chosen in treating this complication. For both prevention and therapy, antimicrobial lock is a major matter of controversy and a promising field for future clinical studies. This article reviews current evidences in terms of epidemiology, pathogenesis and risk factors, diagnosis, prevention, and treatment of totally implantable venous access device-related infections.

High-Dose Daptomycin Is Effective as an Antibiotic Lock Therapy in a Rabbit Model of Staphylococcus epidermidis Catheter-Related Infection

Long-term catheter-related bloodstream infections (CRBSIs) involving coagulase-negative staphylococci are associated with poor patient outcomes, increased hospitalization, and high treatment costs. The use of vancomycin lock therapy has been an important step forward in treatment of these biofilms, although failures occur in 20% of patients. In this study, we report that a high dose of daptomycin lock therapy may offer a therapeutic advantage for these CRBSIs in just 24 h of treatment.

Vascular Access: Past, Present, and Future

Vascular access is the Achilles’ heel of hemodialysis. Current vascular access approaches for hemodialysis include arteriovenous (AV) fistula, AV graft, and central venous catheter. Strengths and weaknesses of each access type are described. New technology and procedures in introducing an access, monitoring access function, and salvaging a non-functioning access are also described.

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.

Salvage Strategy for Long-Term Central Venous Catheter-Associated Staphylococcus aureus Infections in Children

Introduction: Current international guidelines strongly recommend catheter removal in case of S. aureus central line-associated bloodstream infection (CLASBI), but a catheter salvage strategy may be considered in children given age-related specificities. No data is available regarding the outcome of this strategy in children. This study aims to evaluate catheter salvage strategy in children with S. aureus CLABSI, and to determine treatment failure rates and associated risk factors. Methods: We retrospectively analyzed data for all children <18 years having S. aureus CLABSI on a long-term central venous catheter in a tertiary hospital from 2010 to 2014. We defined catheter salvage strategy as a central venous catheter left in place ≥3 days after initiation of empiric treatment for suspected bacteremia, and catheter salvage strategy failure as the persistence or relapse of bacteremia with a S. aureus strain harboring the same antibiotic susceptibility pattern, or the occurrence or the worsening of local or systemic infectious complication between 72 h and 28 days after the first positive blood culture. Results: During the study period, 49 cases of S. aureus CLABSI on long-term central venous catheters were observed in 41 children (including 59% with long-term parenteral nutrition) and 6 (15%) isolates were resistant to methicillin. A catheter salvage strategy was chosen in 37/49 (76%) cases and failed in 12/37 (32%) cases. Initial presence of bloodstream co-infection, serum concentration of vancomycin under the targeted value and inadequate empiric treatment were significantly associated with catheter salvage therapy failure. Conclusions: The catheter salvage strategy of S. aureus CLABSI on a long-term central venous catheter was frequent in the studied hospital and failed only in one third of cases.

Study of Crystal Formation and Nitric Oxide (NO) Release Mechanism from S-Nitroso-N-acetylpenicillamine (SNAP)-Doped CarboSil Polymer Composites for Potential Antimicrobial Applications

Stable and long-term nitric oxide (NO) releasing polymeric materials have many potential biomedical applications. Herein, we report the real-time observation of the crystallization process of the NO donor, S-nitroso-N-acetylpenicillamine (SNAP), within a thermoplastic silicone-polycarbonate-urethane biomedical polymer, CarboSil 20 80A. It is demonstrated that the NO release rate from this composite material is directly correlated with the surface area that the CarboSil polymer film is exposed to when in contact with aqueous solution. The decomposition of SNAP in solution (e.g. PBS, ethanol, THF, etc.) is a pseudo-first-order reaction proportional to the SNAP concentration. Further, catheters fabricated with this novel NO releasing composite material are shown to exhibit significant effects on preventing biofilm formation on catheter surface by Pseudomonas aeruginosa and Proteus mirabilis grown in CDC bioreactor over 14 days, with a 2 and 3 log-unit reduction in number of live bacteria on their surfaces, respectively. Therefore, the SNAP-CarboSil composite is a promising new material to develop antimicrobial catheters, as well as other biomedical devices.

Central venous catheters and biofilms: where do we stand in 2017?

The use of central venous catheters (CVC) is associated with a risk of microbial colonization and subsequent potentially severe infection. Microbial contamination of the catheter leads to the development of a microbial consortia associated with the CVC surface and embedded in an extracellular matrix, named biofilm. This biofilm provides bacterial cells the ability to survive antimicrobial agents and the host immune system and to disseminate to other sites of the body. The best preventive strategy is to avoid any unnecessary catheterization or to reduce indwelling duration when a CVC is required. Beside aseptic care and antibiotic-impregnated catheters (like minocycline/rifampin), preventive locks can be proposed in some cases, whereas non-biocidal approaches are under active research like anti-adhesive or competitive interactions strategies. When the diagnosis of catheter-related bloodstream infection (CRBSI) is suspected on clinical symptoms, it requires a microbiological confirmation by paired blood cultures in order to avoid unnecessary catheter removal. The treatment of CRBSI relies on catheter removal and systemic antimicrobials. However, antibiotic lock technique (ALT) can be used as an attempt to eradicate biofilm formed on the inside lumen of the catheter in case of uncomplicated long-term catheter-related BSI caused by coagulase-negative staphylococci (CoNS) or Enterobacteriaceae. Recently, promising strategies have been developed to improve biofilm eradication; they rely on matrix degradation or destabilization or the development of anti-persister compounds, targeting the most tolerant bacterial cells inside the biofilm. Understanding biofilm formation at the molecular level may help us to develop new approaches to prevent or treat these frequent infections.

Successful Salvage of Central Venous Catheters in Patients with Catheter-Related or Central Line-Associated Bloodstream Infections by Using a Catheter Lock Solution Consisting of Minocycline, EDTA, and 25% Ethanol

In cancer patients with long-term central venous catheters (CVC), removal and reinsertion of a new CVC at a different site might be difficult because of the unavailability of accessible vascular sites. In vitro and animal studies showed that a minocycline-EDTA-ethanol (M-EDTA-EtOH) lock solution may eradicate microbial organisms in biofilms, hence enabling the treatment of central line-associated bloodstream infections (CLABSI) while retaining the catheter in situ Between April 2013 and July 2014, we enrolled 30 patients with CLABSI in a prospective study and compared them to a historical group of 60 patients with CLABSI who had their CVC removed and a new CVC inserted. Each catheter lumen was locked with an M-EDTA-EtOH solution for 2 h administered once daily, for a total of 7 doses. Patients who received locks had clinical characteristics that were comparable to those of the control group. The times to fever resolution and microbiological eradication were similar in the two groups. Patients with the lock intervention received a shorter duration of systemic antibiotic therapy than that of the control patients (median, 11 days versus 16 days, respectively; P < 0.0001), and they were able to retain their CVCs for a median of 74 days after the onset of bacteremia. The M-EDTA-EtOH lock was associated with a significantly decreased rate of mechanical and infectious complications compared to that of the CVC removal/reinsertion group, who received a longer duration of systemic antimicrobial therapy. (This study has been registered at ClinicalTrials.gov under registration no. NCT01539343.).

Evaluation of the usefulness of a quantitative blood culture in the diagnosis of catheter-related bloodstream infection: Comparative analysis of two periods (2002 and 2012)

INTRODUCTION

A retrospective study was conducted to investigate the usefulness of systematic quantitative blood culture (QBC) in the diagnosis of catheter-related bloodstream infection (CRBSI) during two 1-year periods (2002 and 2012).

METHODS

The study included all QBC requests sent to the microbiology laboratory for suspected CRBSI in adults (≥18 years) with any type of intravascular catheter (IVC). Based on a ratio of ≥4:1CFU/mL of the same microorganism between IVC blood culture from any lumen and peripheral blood culture, 5 diagnostic groups were defined: confirmed or probable CRBSI, primary BSI, other focus of infection, and colonization.

RESULTS

In total, 4521 QBCs were evaluated; 24% positive in 2002 and 16% in 2012 (P<0.0001). There were 243 episodes of suspected CRBSI (101 in 2002 and 142 in 2012). Confirmed CRBSI episodes were higher in 2002 than 2012 (56% vs 34%) (P<0.0001), whereas colonization episodes were lower (18% vs 38%) (P=0.0006). Gram-positive cocci decrease in 2012 relative to 2002 (56% vs 79.7%) (P=0.022). Almost one-third (32%) of confirmed CRBSI would have been missed if blood from all catheter lumens had not been cultured.

CONCLUSIONS

QBC is a useful method for diagnosing CRBSI. Blood samples from all catheter lumens must be cultured to avoid missing around one-third of CRBSI diagnoses.

In vitro efficacy of daptomycin and teicoplanin combined with ethanol, clarithromycin or gentamicin as catheter lock solutions

Background

Despite widespread use, optimum choice of antimicrobial agents, concentrations, combinations and exposure times have not been determined for antibiotic lock technique (ALT). Our objective was to evaluate the efficacy of different antibiotic combinations using an in vitro model of catheter-related infection. Daptomycin (DAP) 5 mg/mL, teicoplanin (TEC) 5 mg/mL, both alone and combined with gentamicin (GM) 2.5 mg/mL, clarythromycin (CLA) 5 mg/mL or ethanol 35 % were evaluated against four clinical strains of methicillin resistant coagulase negative staphylococci. Lock solutions were renewed every 24 h.

Results

After 72 h catheters were reincubated with culture media to investigate bacterial regrowth. All antibiotic combinations resulted in significant reductions (p < 0.05) of Log(10) cfu/mL at 72 h for both organisms compared with controls. DAP resulted in significant reductions of Log(10) for all organism versus TEC (p = 0.001). Only DAP reached the limit of detection at 72 h, however did not prevent regrowth after 24 h of ALT removal. DAP + Ethanol and TEC + ethanol eradicated biofilm at 72 h, but only DAP + ethanol (against all strains) and DAP + CLA (against two strains) prevented regrowth at 24 h after ALT removal.

Conclusions

Based on these data, ALT with DAP + ethanol and DAP + CLA should be explored in clinical trials.

Synergy of ambroxol with vancomycin in elimination of catheter-related Staphylococcus epidermidis biofilm in vitro and in vivo

Central venous catheters are widely used in neonatal intensive care units (NICUs) nowadays. The commonest cause of catheter-related bloodstream infections (CRBSIs) is coagulase-negative staphylococci (CoNS). Ambroxol, an active metabolite of bromhexine, exhibits antimicrobial activity against strains producing biofilm and enhances the bactericidal effect of some antibiotic by breaking the structure of biofilm. In this study, we aimed to determine the effect of ambroxol with vancomycin on the biofilm of Staphylococcus epidermidis (S. epidermidis) in vitro and in vivo. In the in vitro study, the biofilm of S. epidermidis was assessed by XTT reduction assay and analysed by confocal laser scanning microscopy (CLSM). In the in vivo study, a rabbit model of CRBSIs was created by intravenous intubation with a tube covered with S. epidermidis biofilm. The rabbits received one of the following four treatments by means of antibiotic lock therapy: normal heparin, ambroxol, vancomycin, or vancomycin plus ambroxol each for 3 days. The microstructure of the biofilm was assessed by scanning electron microscopy (SEM). The number of bacterial colonies in the organs (liver, heart, and kidney) and on the intravenous tubes was measured on agar plates. Pathological changes in the organs (liver, heart, and kidney) were observed with Hematoxylin-Eosin staining. The ambroxol exhibits significant efficacy to potentiate the bactericidal effect of vancomycin on S. epidermidis biofilm both in vitro and in vivo. The antibiotic lock therapy using a combination of ambroxol and vancomycin reveals a high ability to eradicate S. epidermidis biofilms in vivo. These results provide the basis of a useful anti-infection strategy for the treatment of CRBSIs.

Diagnosis and treatment of bacteremia and endocarditis due to Staphylococcus aureus. A clinical guideline from the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC)

Both bacteremia and infective endocarditis caused by Staphylococcus aureus are common and severe diseases. The prognosis may darken not infrequently, especially in the presence of intracardiac devices or methicillin-resistance. Indeed, the optimization of the antimicrobial therapy is a key step in the outcome of these infections. The high rates of treatment failure and the increasing interest in the influence of vancomycin susceptibility in the outcome of infections caused by both methicillin-susceptible and -resistant isolates has led to the research of novel therapeutic schemes. Specifically, the interest raised in recent years on the new antimicrobials with activity against methicillin-resistant staphylococci has been also extended to infections caused by susceptible strains, which still carry the most important burden of infection. Recent clinical and experimental research has focused in the activity of new combinations of antimicrobials, their indication and role still being debatable. Also, the impact of an appropriate empirical antimicrobial treatment has acquired relevance in recent years. Finally, it is noteworthy the impact of the implementation of a systematic bundle of measures for improving the outcome. The aim of this clinical guideline is to provide an ensemble of recommendations in order to improve the treatment and prognosis of bacteremia and infective endocarditis caused by S. aureus, in accordance to the latest evidence published.

Biofilm-related infections: bridging the gap between clinical management and fundamental aspects of recalcitrance toward antibiotics

Surface-associated microbial communities, called biofilms, are present in all environments. Although biofilms play an important positive role in a variety of ecosystems, they also have many negative effects, including biofilm-related infections in medical settings. The ability of pathogenic biofilms to survive in the presence of high concentrations of antibiotics is called "recalcitrance" and is a characteristic property of the biofilm lifestyle, leading to treatment failure and infection recurrence. This review presents our current understanding of the molecular mechanisms of biofilm recalcitrance toward antibiotics and describes how recent progress has improved our capacity to design original and efficient strategies to prevent or eradicate biofilm-related infections.

In vitro activity of gentamicin, vancomycin or amikacin combined with EDTA or l-arginine as lock therapy against a wide spectrum of biofilm-forming clinical strains isolated from catheter-related infections

OBJECTIVES

Treatment of catheter-related bloodstream infections (CRBSI) is hampered by the characteristic tolerance of bacterial biofilms towards antibiotics. Our objective was to study the effect of the combination of antibiotics and the alkaline amino acid l-arginine or the cation chelator EDTA on the bacterial killing of in vitro biofilms formed by an array of clinical strains responsible for CRBSI and representative of epidemiologically relevant bacterial species.

METHODS

Among 32 strains described in a previous clinical study, we focused on the most antibiotic-tolerant strains including CoNS (n = 4), Staphylococcus aureus (n = 4), Enterococcus faecalis (n = 2), Pseudomonas aeruginosa (n = 4) and Enterobacteriaceae (n = 4). We used an in vitro biofilm model (96-well plate assay) to study biofilm tolerance and tested various combinations of antibiotics and non-antibiotic adjuvants. Gentamicin, amikacin or vancomycin was combined with disodium EDTA or l-arginine for 24 h to reproduce the antibiotic lock therapy (ALT) approach. Killing of biofilm bacteria was measured by cfu quantification after a vigorous step of pipetting up and down in order to detach all biofilm bacteria from the surface of the wells.

RESULTS

Both of our adjuvant strategies significantly increased the effect of antibiotics against biofilms formed by Gram-positive and Gram-negative bacterial pathogens. The combination of gentamicin + EDTA was active against all tested strains apart from one P. aeruginosa. The combination of gentamicin + l-arginine was active against most of the tested strains with the notable exception of CoNS for which no potentiation was observed. We also demonstrated that amikacin + EDTA was active against Gram-negative bacteria and that vancomycin + EDTA was active against Gram-positive bacteria.

CONCLUSIONS

The addition of EDTA enhanced the activity of gentamicin, amikacin and vancomycin against biofilms formed by a wide spectrum of bacterial strains responsible for CRBSI.

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.

Stability and compatibility of antimicrobial lock solutions

PURPOSE

Published stability and compatibility data on a growing array of solutions used for antimicrobial lock therapy (ALT) are reviewed.

SUMMARY

ALT involves the instillation of a highly concentrated antimicrobial, often in combination with an anticoagulant, into a central venous catheter (CVC) lumen; this technique is often used for prophylaxis after CVC insertion or as an adjunctive treatment in cases of central line-associated bloodstream infection (CLABSI) if catheter removal is not feasible. Optimal selection of stable and compatible antimicrobials and additives can maximize catheter dwell times, streamline pharmacy compounding practices, and help ensure patient safety. Of 98 articles on ALT solutions identified in a literature search, 17 met the prespecified criteria for the use of validated stability and compatibility methodology. Antimicrobials active against common CLABSI pathogens that may be appropriate for ALT include cefazolin, cefotaxime, ceftazidime, ciprofloxacin, daptomycin, gentamicin, linezolid, telavancin, ticarcillin-clavulanic acid, and vancomycin; validated data demonstrate the stability of these agents in solution with heparin or nonheparin anticoagulants over 72-96 hours or longer. Other antifungal agents and antiinfectives (e.g., ethyl alcohol) have been used in specific patients and ALT situations. The prolonged stability of several antimicrobial-additive combinations may allow for extended dwell times and less frequent lock solution exchanges.

CONCLUSION

Pharmacists' knowledge of diverse combinations of antimicrobial agents and additives in lock solutions, including several shown to be stable and compatible for extended periods, can help expand and optimize the use of ALT in both treatment and prophylactic modalities.

Catheter-related bloodstream infections

Central-venous-catheter-related bloodstream infections (CRBSIs) are an important cause of hospital-acquired infection associated with morbidity, mortality, and cost. Consequences depend on associated organisms, underlying pre-morbid conditions, timeliness, and appropriateness of the treatment/interventions received. We have summarized risk factors, pathogenesis, etiology, diagnosis, and management of CRBSI in this review.

pH-mediated potentiation of aminoglycosides kills bacterial persisters and eradicates in vivo biofilms

BACKGROUND

Limitations in treatment of biofilm-associated bacterial infections are often due to subpopulation of persistent bacteria (persisters) tolerant to high concentrations of antibiotics. Based on the increased aminoglycoside efficiency under alkaline conditions, we studied the combination of gentamicin and the clinically compatible basic amino acid L-arginine against planktonic and biofilm bacteria both in vitro and in vivo.

METHODS

Using Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli bioluminescent strains, we studied the combination of L-arginine and gentamicin against planktonic persisters through time-kill curves of late stationary-phase cultures. In vitro biofilm tolerance towards gentamicin was assessed using PVC 96 well-plates assays. Efficacy of gentamicin as antibiotic lock treatment (ALT) at 5 mg/mL at different pH was evaluated in vivo using a model of totally implantable venous access port (TIVAP) surgically implanted in rats.

RESULTS

We demonstrated that a combination of gentamicin and the clinically compatible basic amino acid L-arginine increases in vitro planktonic and biofilm susceptibility to gentamicin, with 99% mortality amongst clinically relevant pathogens, i.e. S. aureus, E. coli and P. aeruginosa persistent bacteria. Moreover, although gentamicin local treatment alone showed poor efficacy in a clinically relevant in vivo model of catheter-related infection, gentamicin supplemented with L-arginine led to complete, long-lasting eradication of S. aureus and E. coli biofilms, when used locally.

CONCLUSION

Given that intravenous administration of L-arginine to human patients is well tolerated, combined use of aminoglycoside and the non-toxic adjuvant L-arginine as catheter lock solution could constitute a new option for the eradication of pathogenic biofilms.

Long-term catheterization: current approaches in the diagnosis and treatment of port-related infections

Since the first description in 1982, totally implanted venous access ports have progressively improved patients' quality of life and medical assistance when a medical condition requires the use of long-term venous access. Currently, they are part of the standard medical care for oncohematologic patients. However, apart from mechanical and thrombotic complications, there are also complications associated with biofilm development inside the catheters. These biofilms increase the cost of medical assistance and extend hospitalization. The most frequently involved micro-organisms in these infections are gram-positive cocci. Many efforts have been made to understand biofilm formation within the lumen catheters, and to resolve catheter-related infection once it has been established. Apart from systemic antibiotic treatment, the use of local catheter treatment (ie, antibiotic lock technique) is widely employed. Many different antimicrobial options have been tested, with different outcomes, in clinical and in in vitro assays. The stability of antibiotic concentration in the lock solution once instilled inside the catheter lumen remains unresolved. To prevent infection, it is mandatory to perform hand hygiene before catheter insertion and manipulation, and to disinfect catheter hubs, connectors, and injection ports before accessing the catheter. At present, there are still unresolved questions regarding the best antimicrobial agent for catheter-related bloodstream infection treatment and the duration of concentration stability of the antibiotic solution within the lumen of the port.

Antibiotic-lock therapy for long-term catheter-related bacteremia: a review of the current evidence

Catheter-related bloodstream infections (CRBSIs) are a major cause of morbidity and mortality, especially among patients receiving hemodialysis, parenteral nutrition and chemotherapy. Antibiotic-lock therapy (ALT) represents a promising technique in the modern treatment of CRBSIs. In this review, we attempt to clarify the potential role of ALT in the treatment of long-term catheter-related bacteremia, based on the available evidence from published studies reporting on this issue. We identified 28 articles that were considered appropriate to be included in our review, only three of which were comparative studies. There is some evidence that ALT administered concurrently with systemic therapy may represent a significant therapeutic approach for CRBSIs involving long-term catheters. Prolonged infection-free catheter survival in the reported series is suggestive of sterilization of the catheters by ALT. The only reported comparison shows better outcome with ALT than with catheter exchange. Immunodeficient states, such as HIV, and the use of totally implanted devices instead of tunneled catheters may predispose to CRBSI treatment failure. No serious adverse effects, such as emergence of resistance or increased infectious complications, were found to be associated with the use of ALT in the reviewed studies. However, more comparative studies should be performed to examine this important therapeutic issue further.

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.