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

Predictors of Failure of Catheter Salvage in Incident Hemodialysis Patients

Purpose

Catheter-related bloodstream infection is a frequent complication for patients who use catheter as dialysis access. This study was performed to identify the risk factors for failed catheter salvage.

Methods

We enrolled patients who received non-tunneled catheters as initial vascular access during a two-year period. Catheter salvage was attempted in all symptomatically mild patients. Patients were prospectively followed for 8 weeks starting from the day of infection. Risk factors for salvage failure were explored.

Results

A total of 77 bacteremia episodes occurred in 69 patient, with an infection rate of 1.61 per 1,000 catheter days. Salvage was successful in 73.4% of all episodes. We found that higher ferritin levels (greater vs. lower than 500 mg/l, (odds ratio (OR) 6.388, 95% confidence interval (CI) 2.073, 19.686), higher phosphate levels (greater vs. lower than 5.5 mg/dl, OR 4.084, 95% CI 1.391, 11.978) and shorter time intervals between catheterization and infection (within vs. beyond 3 weeks, OR 4.190, 95% CI 1.279, 13.725) predicted salvage failure.

Conclusions

Catheter salvage can be a reasonable initial strategy for symptomatically mild patients. We propose salvaging aggressively and waiting watchfully; however, clinical judgment is prior to any specific management protocol.

[Venous catheter-related infections]

Central venous catheter-related infections can lead to a substantial increase in morbidity and mortality in patients. Nowadays, with the increase in multi-resistant bacteria, the recent appearance of new antibiotics, and the development of new treatment guidelines, means that this has to be constantly reviewed. The objective of this review is to briefly define the epidemiological and pathogenic concepts and to look in detail at the preventive and therapeutic measures of this type of infection. Practical aspects are presented of different clinical situations such as, antibiotic-lock of the central venous catheter, and the withdrawal or maintenance of the catheter.

Clinical outcome after a totally implantable venous access port-related infection in cancer patients: a prospective study and review of the literature

Morbidity and mortality after a totally implantable venous access port (TIVAP)-related infection in oncology patients have rarely been studied. We conducted this study to assess the incidence and factors associated with the following outcome endpoints: severe sepsis or septic shock at presentation, cancellation of antineoplastic chemotherapy, and mortality at week 12. We conducted a prospective single-center observational study including all adult patients with solid cancer who experienced a TIVAP-related infection between February 1, 2009, and October 31, 2010. Patients were prospectively followed for 12 weeks. Among 1728 patients receiving antineoplastic chemotherapy during the inclusion time, 72 had an episode of TIVAP-related infection (4.2%) and were included in the study (median age, 60 yr; range, 28-85 yr). The incidence of complications was 18% for severe sepsis or septic shock (13/72 patients), 30% for definitive cancellation of antineoplastic chemotherapy (14/46 patients who still had active treatment), and 46% for death at week 12 (33/72 patients). Factors associated with severe sepsis or septic shock were an elevated C-reactive protein (CRP) level and an infection caused by Candida species; 4 of the 13 severe episodes (31%) were due to coagulase-negative staphylococci (CoNS). Factors associated with death at week 12 were a low median Karnofsky score, an elevated Charlson comorbidity index, the metastatic evolution of cancer, palliative care, and an elevated CRP level at presentation. Hematogenous complications (that is, infective endocarditis, septic thrombophlebitis, septic pulmonary emboli, spondylodiscitis, septic arthritis, or organ abscesses) were found in 8 patients (11%). In conclusion, patients' overall condition (comorbidities and autonomy) and elevated CRP level were associated with an unfavorable clinical outcome after a TIVAP-related infection. Candida species and CoNS were responsible for severe sepsis or septic shock.

Full and broad-spectrum in vivo eradication of catheter-associated biofilms using gentamicin-EDTA antibiotic lock therapy

Biofilms that develop on indwelling devices are a major concern in clinical settings. While removal of colonized devices remains the most frequent strategy for avoiding device-related complications, antibiotic lock therapy constitutes an adjunct therapy for catheter-related infection. However, currently used antibiotic lock solutions are not fully effective against biofilms, thus warranting a search for new antibiotic locks. Metal-binding chelators have emerged as potential adjuvants due to their dual anticoagulant/antibiofilm activities, but studies investigating their efficiency were mainly in vitro or else focused on their effects in prevention of infection. To assess the ability of such chelators to eradicate mature biofilms, we used an in vivo model of a totally implantable venous access port inserted in rats and colonized by either Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, or Pseudomonas aeruginosa. We demonstrate that use of tetrasodium EDTA (30 mg/ml) as a supplement to the gentamicin (5 mg/ml) antibiotic lock solution associated with systemic antibiotics completely eradicated Gram-positive and Gram-negative bacterial biofilms developed in totally implantable venous access ports. Gentamicin-EDTA lock was able to eliminate biofilms with a single instillation, thus reducing length of treatment. Moreover, we show that this combination was effective for immunosuppressed rats. Lastly, we demonstrate that a gentamicin-EDTA lock is able to eradicate the biofilm formed by a gentamicin-resistant strain of methicillin-resistant S. aureus. This in vivo study demonstrates the potential of EDTA as an efficient antibiotic adjuvant to eradicate catheter-associated biofilms of major bacterial pathogens and thus provides a promising new lock solution.

Antibiotic catheter locks in the treatment of tunneled hemodialysis catheter-related blood stream infection

We prospectively examined the efficacy of systemic antibiotics and antibiotic catheter locks for the treatment of tunneled hemodialysis catheter related blood stream infections (CRBSI). Patients with clinical signs of tunnel or metastatic infection were excluded. All patients with suspected CRBSI were treated empirically with systemic antibiotics at the onset of symptoms before final culture and susceptibility results were available. Once the organism was identified, antibiotics treatment was tailored and antibiotic catheter locks were instilled after each dialysis treatment. Clearance of infection was documented by negative surveillance cultures after completion of antibiotic course. Out of 46 episodes of CRBSI; 16 were due to gram positive organisms, 22 were due to gram negative organisms, and 8 were polymicrobial (≥2 organisms) infections. 19 cases required removal of dialysis catheter. Antibiotic lock protocol was successful for eradicating infection in 27 of 46 episodes (59%). The likelihood of a clinical cure was identical in both gram-positive and gram-negative infections (63% and 62% respectively). Antibiotic lock protocol remains an option in the treatment of clinically stable patients with CRBSI; however, success rate of this protocol in eradicating the infection is modest.

Antibiotic lock solutions allow less systemic antibiotic exposure and less catheter malfunction without adversely affecting antimicrobial resistance patterns

There are current concerns that antibiotic lock solutions (ABL) can induce antimicrobial resistance in long-term hemodialysis patients. Retrospective chart review of 157 children on hemodialysis between January 1997 and June 2006 was performed. In ERA I, only systemic antibiotics were used. In ERA II, ABL were added to systemic antibiotics when needed. In ERA III, ABL were used for treatment of all cases of catheter-related bacteremia (CRB) and for CRB prophylaxis in high-risk patients. The study includes 111,325 catheter days. The CRB incidence was 3.9 CRB/1000 catheter days. There was significant decrease for the total systemic antibiotic exposure (P = 0.0484) and the percentage of catheters lost to malfunction (P = 0.001) in ERA III. Protocol ABL exposure was associated with a trend to increased tobramycin-gentamicin resistance for gram-positive CRBs (P = 0.2586) but with improved tobramycin-gentamicin resistance for gram-negative (P = 0.0949) and polymicrobial CRBs (P = 0.1776) and improved vancomycin resistance for gram-positive CRBs (P = 0.0985). This retrospective analysis does not support the premise that ABL use will promote antimicrobial resistance in the hemodialysis population. The decreased exposure to systemic antibiotics by vigorous ABL use may even improve the antimicrobial resistance patterns in this population in the long term.

A rat model of central venous catheter to study establishment of long-term bacterial biofilm and related acute and chronic infections

Formation of resilient biofilms on medical devices colonized by pathogenic microorganisms is a major cause of health-care associated infection. While in vitro biofilm analyses led to promising anti-biofilm approaches, little is known about their translation to in vivo situations and on host contribution to the in vivo dynamics of infections on medical devices. Here we have developed an in vivo model of long-term bacterial biofilm infections in a pediatric totally implantable venous access port (TIVAP) surgically placed in adult rats. Using non-invasive and quantitative bioluminescence, we studied TIVAP contamination by clinically relevant pathogens, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis, and we demonstrated that TIVAP bacterial populations display typical biofilm phenotypes. In our study, we showed that immunocompetent rats were able to control the colonization and clear the bloodstream infection except for up to 30% that suffered systemic infection and death whereas none of the immunosuppressed rats survived the infection. Besides, we mimicked some clinically relevant TIVAP associated complications such as port-pocket infection and hematogenous route of colonization. Finally, by assessing an optimized antibiotic lock therapy, we established that our in vivo model enables to assess innovative therapeutic strategies against bacterial biofilm infections.

Prevention and management of central line-associated bloodstream infections in hospital practice

In this article aimed at hospitalists, we examine the literature on preventive measures for central line-associated bloodstream infections (CLABSIs) and optimal management once a CLABSI has been established. We focus on a number of core preventive measures and the contemporary approach of bundling these measures for maximal impact in reducing infection rates. We then discuss empiric and pathogen-specific antibiotic therapy, including the role of newer antimicrobial agents, as well as the management of an infected central venous catheter.

sTREM-1 and LBP in central venous catheter-associated bloodstream infections in pediatric intestinal failure

OBJECTIVE

Central venous catheter-associated bloodstream infections (CVC-BSIs) are a major cause of morbidity and mortality in the pediatric intestinal failure (IF) population. We assessed plasma lipopolysaccharide-binding protein (LBP) and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) as biomarkers for CVC-BSI. We hypothesized that sTREM-1 and LBP rise with BSI and decline following treatment, and that baseline LBP is higher in the IF population than in controls.

PATIENTS AND METHODS

Patients younger than 4 years were recruited from the IF registry at Cincinnati Children's Hospital. LBP and sTREM-1 levels were measured on 22 patients with IF at baseline, 17 patients with IF with BSIs, and 11 healthy controls.

RESULTS

Mean sTREM-1 level (pg/mL) and LBP level (μg/mL) rose with CVC-BSI over baseline (115.0 ± 51.2 vs 85.9 ± 27.6, P = 0.011 and 79.8 ± 45.4 vs 20.5 ± 11.3, P < 0.001, respectively) and declined following antibiotic therapy (115.0 ± 51.2 vs 77.9 ± 29.8, P = 0.003 and 79.8 ± 45.4 vs 26.2 ± 10.8, P < 0.001, respectively). Receiver operating characteristic curves showed that neither sTREM-1 nor LBP is sufficient to predict bacteremia versus fever without bacteremia (area under these curves = 0.57 and 0.82, respectively). Baseline LBP was higher in hospitalized patients than in outpatients (27.5 ± 8.7 vs 13.5 ± 9.2, P = 0.002), patients with previous BSIs versus those without (23.5 ± 10.4 vs 10.1 ± 8.3, P = 0.016), and those listed for transplantation versus those not listed (29.6 ± 9.8 vs 16.2 ± 9.5, P = 0.033).

CONCLUSIONS

sTREM-1 and LBP rise with CVC-BSI in IF and decline after treatment; however, neither distinguishes infection from nonbacteremic febrile episodes. Baseline LBP may be a marker of disease severity in IF.

Clinical management of dialysis catheter-related bacteremia with concurrent exit-site infection

Dialysis catheter-related bacteremia (CRB) can frequently be treated with systemic antibiotics, in conjunction with an antibiotic lock, in an attempt to salvage the catheter. It is unknown whether CRB associated with an exit-site infection can be treated with such an approach. We retrospectively queried a prospective, computerized vascular access database, and identified 1436 episodes of CRB, of which 64 cases had a concurrent exit site. The frequency of concurrent exit-site infection was 9.6% with Staphylococcus epidermidis, 6.1% with Staphylococcus aureus, and only 0.7% with Gram negative CRB (p < 0.001 for Staphylococcus vs. Gram negative rods). Five serious complications (four major sepses and one endocarditis) occurred in 24 patients with S. aureus infection, but none in 32 episodes of S. epidermidis infection (p = 0.01). Catheter survival was significantly shorter in patients with S. aureus infections. The median catheter survival (without infection or dysfunction) was 14 days with S. aureus vs. 30 days with S. epidermidis infection (p = 0.035). In conclusion, concurrent exit-site infection is seen most commonly in association with Staphylococcal CRB. When the infecting organism is S. epidermidis, attempted salvage with systemic antibiotics and an antibiotic lock is reasonable. However, prompt catheter removal is indicated when the pathogen is S. aureus.

The spectrum of infections in catheter-dependent hemodialysis patients

BACKGROUND AND OBJECTIVES

Catheter-dependent hemodialysis patients may develop access-related and nonaccess-related infections that may be managed in the outpatient arena or in the hospital. The goal of this study was to quantify infections in such patients, to characterize their clinical presentations, and to evaluate factors determining need for hospitalization.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We collected prospective data on the clinical management of catheter-dependent hemodialysis patients with suspected infection at a large dialysis center. We documented the presenting symptoms, type of infection, pathogen, and whether hospitalization occurred.

RESULTS

An infection was suspected in 305 separate cases and confirmed in 88%. The 268 diagnosed infections included catheter-related bacteremia (69%), another access-related infection (19%), and nonaccess-related infection (12%). The overall frequency of infection was 4.62 per 1000 catheter-days. Hospitalization occurred in 37% of all infections, but it varied greatly (72% for nonaccess-related infection, 34% for catheter-related bacteremia, and 4% for exit-site infection). Among patients with catheter-related bacteremia, the likelihood of hospitalization varied by pathogen, being 53% for Staphylococcus aureus, 30% for Enterococcus, 23% for Staphylococcus epidermidis, and 17% for gram-negative rods (P < 0.001). The likelihood of hospitalization was not associated with age, gender, or diabetes. Fever was a presenting symptom in only 47% of cases of catheter-related bacteremia.

CONCLUSIONS

Catheter-dependent patients have a high burden of infection. It is important to evaluate patients with suspected infection for various access-related and nonaccess-related infections. A low threshold is indicated for suspecting catheter-related bacteremia because the patients frequently present without fever.

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.

Anti-infective locks for treatment of central line-associated bloodstream infection: a systematic review and meta-analysis

Central line-associated bloodstream infections (CLABSI) are associated with considerable morbidity, mortality and economic costs. In most cases, catheter removal is considered an essential component of managing CLABSI. However, in patients with poor access, catheter salvage may have to be attempted rather than removal and replacement of catheters. Anti-infective lock therapy (ALT) - instilling an antibiotic or antiseptic into the catheter lumen - is a novel way of treating CLABSI while attempting to salvage the catheter. However, data on the efficacy of ALT for catheter salvage is limited. In this systematic review, we critically review the evidence regarding the use of ALT for catheter salvage. We identified 8 studies including a total of 396 patients that compared ALT with systemic antibiotic therapy alone or an alternate method of catheter salvage (guidewire replacement). We found that the combination of systemic antibiotics and culture-guided lock therapy was superior to systemic antibiotics alone (OR: 0.20, 95% CI: 0.10-0.39), with 10% of locked patients requiring replacement compared to 33% of subjects without locks. There was a 20% relapse rate in the ALT group and a 30% relapse rate in the control group (OR: 0.43, 95% CI: 0.18-1.03). There was insufficient data on catheter exchange over a wire compared with ALT to permit conclusions. Our data support the use of ALT in conjunction with systemic antibiotics for catheter salvage. Large randomized controlled trials of ALT examining dose, dwell times and relapse rates stratified by infecting pathogen are needed.

Clinical outcome of catheter salvage in neutropenic cancer patients with catheter-related infection

BACKGROUND

Catheter-related infections (CRI) cause significant morbidity and mortality in cancer patients, particularly during episodes of chemotherapy-induced neutropenia. This study was performed to evaluate clinical features and outcomes of CRI in neutropenic cancer patients.

METHODS

We retrospectively analyzed clinical characteristics and outcome of febrile neutropenic cancer patients with CRI who visited the emergency department from January 1996 to June 2007.

RESULTS

A total of 51 neutropenic cancer patients with CRI were identified and 53 organisms were isolated from culture specimens. The mean ± standard deviation patient age was 50 ± 15 y and the most common underlying disease was lymphoma (n = 27, 53%). Gram-positive organisms accounted for 77% of all isolated pathogens (41/53). Initial catheter salvage was attempted in 38 episodes of CRI, of which 20 were successful. In the current study the overall success rate of catheter salvage attempts was 52.6%. The failure rate of catheter salvage was significantly higher in CRI caused by Gram-negative pathogens than by Gram-positive pathogens.

CONCLUSION

Although catheter salvage should be cautiously attempted for cancer patients with CRI, it might not be a treatment option for neutropenic cancer patients with CRI caused by Gram-negative bacteria.

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.

Current strategies for the prevention and management of central line-associated bloodstream infections

Central venous catheters are an invaluable tool for diagnostic and therapeutic purposes in today’s medicine, but their use can be complicated by bloodstream infections (BSIs). While evidence-based preventive measures are disseminated by infection control associations, the optimal management of established central line-associated BSIs has been summarized in infectious diseases guidelines. We prepared an overview of the state-of-the-art of prevention and management of central line-associated BSIs and included topics such as the role of antibiotic-coated catheters, the role of catheter removal in the management, and a review of currently used antibiotic compounds and the duration of treatment.

Clinical outcomes of antimicrobial lock solutions used in a treatment modality: a retrospective case series analysis

BACKGROUND

Antimicrobial lock therapy (ALT) may be considered as adjunctive therapy in the treatment of catheter-related bloodstream infections (CRBSI) when catheter removal is not a favorable option.

OBJECTIVE

To evaluate the outcomes associated with ALT as adjunctive treatment of CRBSI.

METHODS

This was a 24-month retrospective case series analysis evaluating patients treated for more than 24 hours with ALT. The primary outcome was blood culture sterilization for 30 days posttherapy. The impact of ALT duration and time to initiation on central venous catheter (CVC) salvage were evaluated. Logistic regression modeled the association between ALT and sterilization rates, with a prespecified level of significance (α) of 0.1.

RESULTS

Twenty-six cases were included in data analysis. Patients included ranged from 5 months to 82 years of age; 77% of patients were receiving total parenteral nutrition or chemotherapy. The majority of patients received vancomycin, daptomycin, or gentamicin combined with heparin in a lock solution. Blood culture sterilization was achieved in 69.2% of cases, and sterilization plus CVC retention was achieved in 11 cases (42.3%). Longer durations of ALT (≥9 days) were significantly correlated with blood culture sterilization (odds ratio = 1.367, P = 0.077).

CONCLUSION

ALT used as an adjunct to systemic therapy for adequate duration in CRBSI can achieve CVC sterilization and retainment without subsequent infectious complications.

PREFABL: predictors of failure of antibiotic locks for the treatment of catheter-related bacteraemia

BACKGROUND

Antibiotic lock (ABL) solutions can effectively treat catheter-related bacteraemia (CRB) without the need for catheter exchange. This approach does not increase secondary infectious complications. We evaluated the risk factors that contribute to failure when CRB is treated with ABLs and systemic antibiotics in paediatric haemodialysis patients.

METHODS

A retrospective chart review of 72 children on haemodialysis between January 2004 and June 2006 was performed. We evaluated risk factors for ABL treatment using patients' characteristics, CRB/catheter characteristics and patients' biochemical profiles. The first CRB of each catheter was included in the statistical analysis. Our end points were outcome at 2 weeks of treatment and at 6 weeks following treatment. Compound symmetry covariance structure was employed for statistical analysis.

RESULTS

We treated 149 CRB in 50 patients. The incidence was 3.4 CRB/1000 catheter days. Thirty CRB failed to be cleared with the use of ABL and systemic antibiotics at 2 weeks of treatment (30/149, 20 vs 80%, P < 0.001). Twenty-four of these catheters required exchange. Thirty-nine of the treated catheters got re-infected within the next 6 weeks (39/125, 31 vs 69%, P < 0.001). CRB aetiology was the only statistically significant independent variable for 2-week outcome (P = 0.033). Coagulase-negative Staphylococcus CRB had higher odds of being cleared at 2 weeks compared with other CRB aetiologies. For the 6-week outcome, the statistically significant independent variables in the final model included age (P = 0.048) and serum phosphorous level (P < 0.001). Younger age and higher serum phosphorous levels were independent risk factors for failure at 6 weeks with re-infection. Area under the receiver operating characteristic (ROC) curve for the model of the 2-week outcome was 0.736 with the percentage of correct predictions at 81.2%. Area under the ROC curve for the model of the 6-week outcome was 0.689 with the percentage of correct predictions at 75.5%.

CONCLUSIONS

CRB can effectively be treated with ABLs and systemic antibiotics. CRB aetiology is the only independent variable of early treatment failure. Younger age and higher serum phosphorous levels are independent risk factors for re-infection at 6 weeks.

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.

Comparison of various antimicrobial agents as catheter lock solutions: preference for ethanol in eradication of coagulase-negative staphylococcal biofilms

Coagulase-negative staphylococci (CoNS) are the main causative agents of bacteraemia in infants managed in neonatal intensive care units (NICUs). Intraluminal colonization of long-term central venous catheters by these bacteria and subsequent biofilm formation are the prerequisites of the bloodstream infections acquired in NICUs. The catheter lock technique has been used to treat catheter colonization; however, the optimum choice of antimicrobial agents and their corresponding concentrations and exposure times have not been determined. The effectiveness of catheter lock solutions (CLSs) was assessed by determining the minimal biofilm eradication concentration of antimicrobial agents against CoNS biofilms. Five conventional antibiotics (oxacillin, gentamicin, vancomycin, ciprofloxacin and rifampicin) alone or in combination, as well as ethanol, were evaluated. Ethanol was found to be superior to all of these conventional antibiotics when used as a CLS. A time–kill study and confocal laser scanning microscopy revealed that exposure to 40 % ethanol for 1 h was sufficient to kill CoNS biofilm cells. To our knowledge, this is the first in vitro study to provide solid evidence to support the rationale of using ethanol at low concentrations for a short time as a CLS, instead of using conventional antibiotics at high concentrations for a long period to treat catheter-related bloodstream infections.

[Consensus document for the treatment of bacteremia and endocarditis caused by methicillin-resistent Staphylococcus aureus. Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica]

Bacteremia and endocarditis due to methicillin-resistant Staphylococcus aureus (MRSA) are prevalent and clinically important. The rise in MRSA bacteremia and endocarditis is related with the increasing use of venous catheters and other vascular procedures. Glycopeptides have been the reference drugs for treating these infections. Unfortunately their activity is not completely satisfactory, particularly against MRSA strains with MICs > 1 microg/mL. The development of new antibiotics, such as linezolid and daptomycin, and the promise of future compounds (dalvabancin, ceftobiprole and telavancin) may change the expectatives in this field.The principal aim of this consensus document was to formulate several recommendations to improve the outcome of MRSA bacteremia and endocarditis, based on the latest reported scientific evidence. This document specifically analyzes the approach for three clinical situations: venous catheter-related bacteremia, persistent bacteremia, and infective endocarditis due to MRSA.

Microbial inactivation properties of a new antimicrobial/antithrombotic catheter lock solution (citrate/methylene blue/parabens)

Background. Microbial infections are the most serious complications associated with indwelling central venous catheters. A catheter lock solution that is both antibacterial and antithrombotic is needed. The goal of this study was to determine whether a new catheter lock solution containing citrate, methylene blue and parabens has antimicrobial properties against planktonic bacteria and against sessile bacteria within a biofilm. These effects were compared to the antimicrobial properties of heparin at 2500 units/ml.

Methods. The tested solution (C/MB/P comprising 7% sodium citrate, 0.05% methylene blue and 0.165% parabens) and individual components were challenged against gram-positive and gram-negative organisms and fungi. Control solutions were heparin with preservatives. Studies included evaluation of eradication of planktonic bacteria and sessile organisms in a biofilm grown on polymeric and glass coupons. Biofilm samples were inspected by scanning electron microscopy, atomic force microscopy and vital stains.

Results. The C/MB/P solution, contrary to heparin, kills most tested planktonic microorganisms within 1 h of incubation. All tested organisms have an MIC of 25% or less of the original concentration of a new catheter lock. Bacteria strains did not develop resistance over more than 40 passages of culture suspensions. The C/MB/P solution is able to kill nearly all sessile bacteria in biofilm growth on plastic or glass discs in 1 h. Microscopic methods demonstrated extensive physical elimination of biofilm deposits from treated coupons. In contrast, heparin had a minimal effect on planktonic or biofilm organisms.

Conclusions. The new multicomponent lock solution has strong antimicrobial properties against both planktonic and sessile microorganisms. By comparison, heparin with preservative has weak antibacterial properties against planktonic and biofilm bacteria. The tested catheter lock may have usefulness in preventing bacterial colonization of haemodialysis catheters and diminishing the incidence of catheter-related bacteraemia.

Treatment of dialysis catheter-related Enterococcus bacteremia with an antibiotic lock: a quality improvement report

BACKGROUND

Catheter-related bacteremia (CRB) is a frequent complication of tunneled dialysis catheters, and Enterococcus is a common infecting organism. CRB may be treated by instilling an antibiotic lock into the catheter lumen in conjunction with systemic antibiotics. The efficacy of this approach in Enterococcus bacteremia is unknown.

DESIGN

Quality improvement report.

SETTING & PARTICIPANTS

64 catheter-dependent hemodialysis outpatients with vancomycin-sensitive Enterococcus bacteremia treated with a uniform antibiotic lock protocol. Clinical outcomes were tracked prospectively. QUALITY IMPROVEMENT PLANS: Patients received intravenous vancomycin for 3 weeks in conjunction with a vancomycin lock instilled into both catheter lumens after each dialysis session.

MEASURES

Treatment failure was defined as persistent fever 48 hours after initiation of antibiotic therapy or recurrent Enterococcus bacteremia within 90 days. A clinical cure was defined as fever resolution without recurrent bacteremia. Major infection-related complications within 6 months were documented.

RESULTS

Treatment failure occurred in 25 patients (39%) because of persistent fever in 10 and recurrent bacteremia in 15. Treatment success occurred in 39 patients (61%). A serious complication of Enterococcus CRB occurred in 4 of 64 patients (6%); endocarditis in 1 and osteomyelitis in 3. The frequency of serious complications was 16% (4 of 25 patients) in those with treatment failure compared with 0% (0 of 39 patients) in those with treatment success (P = 0.01).

LIMITATIONS

This was a single-center study. We did not measure serum vancomycin.

CONCLUSIONS

An antibiotic lock protocol permits catheter salvage in 61% of hemodialysis patients with Enterococcus CRB. Serious complications occur in 6% of patients and are more common in those with treatment failure.

What information should lead to a suspicion of catheter sepsis in HPN?

BACKGROUND & AIMS

The diagnosis of catheter sepsis in patients on home parenteral nutrition can be difficult and patients often do not present with classical symptoms of pyrexia whilst feeding. This study reviews the clinical and diagnostic criteria needed to diagnose catheter sepsis.

METHODS

A retrospective consecutive notes review of 2 years of patients presenting with catheter infections assessed symptoms, inflammatory markers and some liver function tests. The same data was also collected on those same patients who had successfully under gone line salvage. The two sets were compared using the Mann-Whitney U-test and predictive calculations were carried out using receiver operated characteristic curves.

RESULTS

Over the two year period there were 37 episodes of CRBSI in 31 patients recorded. Successful catheter salvage was achieved in 30 episodes (in 24 patients) which is an 81% salvage rate. The most significant abnormality seen was a raised C-reactive protein, but less than a third of patients had a raised white cell count. However, there were significant changes in the bilirubin (p=0.0007) and albumin (p=0.0013) in these patients. Almost a third of patients who feel unwell do not present with a raised temperature.

CONCLUSIONS

The diagnosis of CRBSI remains difficult, but it should be suspected in patients with newly abnormal CRP, albumin or bilirubin and in the non-specifically unwell patient a clinician should not be misled by a normal white cell count and apyrexia.

Comparison of early versus late use of antibiotic locks in the treatment of catheter-related bacteremia

BACKGROUND AND OBJECTIVES

This retrospective study compared the effectiveness of the timing of the antibiotic locks to clear catheter-related bacteremia in children on chronic hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The early antibiotic lock group received antibiotic locks along with systemic antibiotics from the very beginning of catheter-related bacteremia. The late antibiotic lock group was given only systemic antibiotics initially, and antibiotic locks were used late in the infection if the catheter-related bacteremia could not be cleared after resolution of symptoms.

RESULTS

There were 264 catheter-related bacteremias in 79 children during 6 yr of observation. Early antibiotic locks were able to clear catheter-related bacteremia and resolve the symptoms more effectively without the need for catheter exchange when compared with late antibiotic locks. A total of 84 catheter-related bacteremias required wire-guided exchange of the catheters. Late antibiotic locks required wire-guided catheter exchange more frequently than the early antibiotic locks. The post-catheter-related bacteremia infection-free survival of the catheters after wire-guided exchange were significantly longer than those of both antibiotic lock groups. Recurrence of catheter-related bacteremia within 45 d after wire-guided exchange occurred at similar rates compared with the antibiotic lock groups.

CONCLUSION

Antibiotic locks are significantly more effective in clearing catheter-related bacteremia when used early in infection, diminishing the need for catheter exchange. Wire-guided exchange has a late-onset advantage for infection-free survival compared with catheter in situ treatment. The recurrence rates in the first 45 d after catheter-related bacteremia are similar regardless of the treatment strategy.

Treatment of catheter-related bacteremia with tissue plasminogen activator antibiotic locks

This retrospective study was completed to investigate the effectiveness of tissue plasminogen activator (TPA) antibiotic locks (ABL) along with systemic antibiotics (AB) to clear catheter-related bacteremia (CRB) in children on chronic hemodialysis. There were 76 CRBs in 37 children. CRBs were successfully cleared with AB/ABL in 63/76 (83%) cases. Ten of 76 (13%) CRBs were symptomatic at 48 h of treatment. These were seven polymicrobial, two gram-negative, and one Candida CRB. 13/76 (17%) episodes required catheter exchange, and all were wire-guided exchanges. TPA-ABL/AB cleared gram-positive and gram-negative CRBs significantly better than polymicrobial CRBs (p < 0.01). The infection-free survival and the rate of recurrence at 45 days was not statistically different between the TPA-ABL/AB group and the catheter-exchange group. If CRB was symptomatic at 48 h of treatment, recurrence at 6 weeks was more frequent with persistent use of TPA-ABL/AB (p < 0.05). There were no episodes of metastatic infections, catheter malfunction from occlusion, or catheter breakdown during the course of TPA-ABL treatments. In conclusion, TPA-ABL can be safely and effectively used in the management of CRB, increasing the probability of catheter survival and preserving the vascular access site. With the exception of polymicrobial CRB, there is no disadvantage in using TPA-ABL/AB over catheter exchange, as the infection-free survival and the rate of recurrence are comparable.

Decreasing gradient of antibiotic concentration in the lumen of catheters locked with vancomycin

The purpose of this study was to investigate if vancomycin concentration is maintained along the lumen of dialysis catheters after 48 h of lock therapy. Each lumen of nine catheters (three subclavian and six femoral) was locked with 2,500 mg/l of vancomycin for 48 h. After that period, the content of the lumen was aspirated with three different syringes of 0.4 ml each to measure the proximal, medial and distal vancomycin concentration. Vancomycin concentration was measured using a homogeneous particle-enhanced turbidimetric inhibition immunoassay. A non-parametric ANOVA, by means of a rank transformation on the antibiotic concentration, was used to assess the influence of the catheter segment (proximal, medial and distal) and the catheter type (femoral or subclavian). A significant decrease in vancomycin concentration from proximal to distal segments was observed (p < 0.001). In addition, the vancomycin concentration in subclavian catheters was significantly higher than in femoral catheters (p < 0.001). In our study there was a decreasing gradient in vancomycin concentration from proximal to distal segments of the catheter. This may explain the failure of antibiotic lock-therapy.

Treatment of dialysis catheter-related Staphylococcus aureus bacteremia with an antibiotic lock: a quality improvement report

BACKGROUND

Dialysis catheter-related bacteremia is often treated successfully by instilling an antibiotic-heparin solution into the catheter lumen (an antibiotic lock) in conjunction with systemic antibiotic therapy without removal of the catheter. The efficacy of this therapy is uncertain in Staphylococcus aureus bacteremia.

DESIGN

Quality improvement report.

SETTING & PARTICIPANTS

113 catheter-dependent hemodialysis outpatients with S aureus catheter-related bacteremia treated with a standardized antibiotic lock protocol. Data for all patients with catheter-related bacteremia are recorded in a prospective database.

QUALITY IMPROVEMENT PLAN

In conjunction with systemic antibiotic therapy (vancomycin for methicillin-resistant S aureus or cefazolin for methicillin-sensitive S aureus), an antibiotic lock was instilled into each catheter lumen after each dialysis session for 3 weeks.

MEASURES

Treatment failure is defined as persistent fever after 48 hours of antibiotic therapy or recurrent S aureus bacteremia within 90 days. Clinical cure is defined as resolution of fever and no recurrence of bacteremia. Major infection-related complications within 6 months were documented.

RESULTS

The catheter could not be salvaged in 67 patients (59%) because of persistent fever in 40 patients and recurrent bacteremia in 27 patients. A clinical cure was achieved in 46 patients (41%). A serious complication of catheter-related bacteremia occurred in 9.7% of all patients (11 of 113 patients). Serious complications were observed in 25% of patients (10 of 40 patients) with persistent fever, but only 1.4% of all other patients (1 of 73 patients; P < 0.0001).

LIMITATIONS

This was a single-center study. Serum antibiotic levels were not measured.

CONCLUSIONS

Routine antibiotic lock therapy is not appropriate for patients with S aureus catheter-related bacteremia. Serious complications occur primarily in patients with persistent fever.

Guidelines on the insertion and management of central venous access devices in adults

Central venous access devices are used in many branched of medicine where venous access is required for either long-term or a short-term care. These guidelines review the types of access devices available and make a number of major recommendations. Their respective advantages and disadvantages in various clinical settings are outlined. Patient care prior to, and immediately following insertion is discussed in the context of possible complications and how these are best avoided. There is a section addressing long-term care of in-dwelling devices. Techniques of insertion and removal are reviewed and management of the problems which are most likely to occur following insertion including infection, misplacement and thrombosis are discussed. Care of patients with coagulopathies is addressed and there is a section addressing catheter-related problems.