Persistent catheter-related bacteremia: clearance with antibiotics and urokinase

Urokinase-based lock solutions for catheter salvage: A case of an upcoming kidney transplant recipient

Catheter-related bloodstream infection (CRBSI) is a significant complication among patients on haemodialysis (HD) who are dependent on a central venous catheter (CVC) for an extended period. Catheter removal as first-line treatment can induce accelerated venous access site depletion in patients on HD who rely on it to survive. It is possible to retain the catheter in stable patients without septic syndrome while administering systemic antibiotics and antibiotic lock therapy. Herein, we report the case of a patient on HD with CRBSI who was successfully treated with intravenous levofloxacin- and urokinase-based antibiotic lock, without catheter removal prior to kidney transplantation. The use of urokinase in combination with antibiotics in lock solutions for treating catheter infections is rare. We verified the physical compatibility of levofloxacin and urokinase by visual inspection, turbidimetric measurements, and particle count. To our knowledge, this was a rare case demonstrating the effective use of urokinase and levofloxacin in a catheter lock for CRBSI in a patient on HD. Considering the need for highly concentrated antimicrobials and the availability of various antibiotics, the compatibility and stability of the lock solution is a matter of concern. Further studies are warranted to assess the stability and compatibility of various antibiotics in combination with urokinase.

Urokinase Lock or Flush Solution for Prevention of Bloodstream Infections Associated with Central Venous Catheters for Chemotherapy: A Meta-Analysis of Prospective Randomized Trials

Background

Intravascular devices (IVDs) carry significant risk of device-associated bloodstream infection (BSI). Catheter thrombosis increases the likelihood of microbial colonization of the catheter and BSI. Urokinase has been studied for the prevention of BSI associated with IVDs. We undertook a systematic review to determine the efficacy of urokinase-heparin lock or flush solution compared with heparin alone in preventing IVD-associated BSI.

Methods

Computerized databases were searched for relevant publications in English from January 1966 to 1 January 2007. We identified randomized controlled trials comparing a urokinase-heparin lock or flush solution with heparin alone for prevention of BSI associated with long-term IVDs. Summary effect sizes were calculated with assessment of heterogeneity.

Results

Five randomized, controlled trials involving a total of 991 patients being treated with IVDs met the inclusion criteria; all five studies were conducted among patients with cancer; three of these studies were undertaken in children and two in adults. The summary risk ratio with a urokinase-heparin lock solution for IVD-associated BSI was 0.77 (95% confidence interval [CI], 0.60–0.98; p=0.01). Results of the test for heterogeneity were not statistically significant (p=0.53).

Conclusions

Use of a urokinase lock solution in high-risk patient populations being treated with long-term central IVDs may reduce the risk of BSI. However, there are few randomized trials and methodologic limitations of these preclude more robust recommendations regarding the use of urokinase to prevent BSI. Further adequately powered studies should seek to evaluate the efficacy of urokinase and optimize dosage and instillation regimen.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Interventions other than anticoagulants and systemic antibiotics for prevention of central venous catheter-related infections in children with cancer

BACKGROUND

Use of central venous catheters (CVC) in treatment of children with cancer is associated with infective complications. Current evidence-based guidelines to prevent catheter-related infections are mainly relevant to the adult population. They are not cancer (especially not childhood cancer) specific. Two existing Cochrane reviews have looked at prophylactic antibiotics and anticoagulants to prevent CVC-related infections.

OBJECTIVES

The primary objective was to find which interventions, if any, were effective in preventing CVC-related infections in children with cancer. Further objectives were to examine the effectiveness of each intervention in the following subgroups: implanted versus external catheters, haematological versus non-haematological malignancies, and in those receiving haematopoietic stem cell transplants (HSCT) versus no HSCT.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2008, Issue 4), MEDLINE (January 1950 to January 2009), EMBASE (January 1980 to January 2009) and CINAHL(R) (January 1982 to March 2009). We also searched reference lists of relevant articles and proceedings of relevant international conferences (2004 to 2008).

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing any intervention (other than anticoagulants, systemic antibiotics and antibiotic lock techniques) versus no intervention, placebo or any other intervention to prevent CVC-related infections in children with cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, assessed trial quality and extracted data. Where necessary, we contacted study authors for further data and clarification of methods.

MAIN RESULTS

Three trials involving two different interventions were included. Two trials involving 680 children compared flushing CVC with urokinase (with or without heparin) versus heparin alone. Neither of these trials reported on the primary outcome of catheter-related blood stream infection (CRBSI). There was a non-significantly decreased rate of catheter-associated infection (CAI) (Rate Ratio 0.72, 95% confidence interval 0.12 to 4.41) in the urokinase (with or without heparin) arm compared with the heparin arm.One trial involving 113 children compared frequency of catheter dressing change every 15 days versus every 4 days. It did not report on CRBSI or CAI. There were no premature catheter removals for infection in either of the trial arms.

AUTHORS' CONCLUSIONS

Three RCTs for only two types of interventions to prevent CVC-related infections in children with cancer have been identified. Flushing CVC with urokinase (with or without heparin) compared to heparin alone possibly leads to decrease in CAI rates. Changing catheter dressings every 15 days versus every 4 days does not lead to more premature catheter removals due to infection although data were insufficient to assess if catheter-related infection rates were changed.

Tissue plasminogen activator to prevent central venous access device infections: a systematic review of central venous access catheter thrombosis, infection and thromboprophylaxis

The recent unequivocal demonstration that prophylaxis, three to four weekly factor infusions, is effective in preventing joint disease in children with haemophilia, has provided impetus to initiate prophylaxis early in such children. Yet, nearly a quarter (22%) of the 83% who required central venous access devices for factor infusion developed central venous access catheter (CVAD)-related infection. This limitation of CVAD use prevents many families from initiating prophylaxis. The frequent occurrence of local thrombosis accompanying CVAD-related infection in surgical patients and autopsy cases, the thrombogenic plastic CVAD surfaces, and local clot formation at the insertion site, suggest the potential role of thrombolytic agents in preventing these infections. Yet, correlation between CVAD-related infection and local thrombosis in children with haemophilia are lacking, and thromboprophylaxis to prevent CVAD-related infection is controversial. Tissue plasminogen activator (t-PA), a recombinant serine protease glycoprotein that lyses plasmin-bound fibrin and is safe and effective in the treatment of occluded catheters, has not been evaluated in the prevention of these infections. We performed a literature review of CVAD-related infection, CVAD-related thrombosis, and thromboprophylaxis studies to evaluate the role of t-PA in the prevention of these infections in children with haemophilia. Metanalysis of published thromboprophylaxis trials demonstrate current prophylaxis regimens do not prevent CVAD infection, and further, that thrombosis and infection do not necessarily occur simultaneously. Pilot data demonstrate CVAD infection reduction in haemophilic children by monthly t-PA in 18 haemophilic children, suggesting the potential role of t-PA in CVAD infection prevention. Clinical trials to evaluate t-PA in CVAD infection prevention are justified.

Diagnosis and treatment of catheter-related infections in paediatric oncology: an update

Otherwise unexplained clinical signs of infection in patients with long-term tunnelled or totally implanted central venous access devices (CVADs) are suspected to be CVAD-associated. Diagnostic methods include catheter swabs, blood cultures and cultures of the catheter tip or port reservoir. In the case of a suspected CVAD-related bloodstream infection in paediatric oncology patients, in-situ treatment without prompt removal of the device can be attempted. Removal of the CVAD should be considered if bacteraemia persists or relapses > or = 72 h after the initiation of (in-vitro effective) antibacterial therapy administered through the line. Timely removal of the device is also recommended if the patient suffers from a complicated infection, or if Staphylococcus aureus, Pseudomonas aeruginosa, multiresistant Acinetobacter baumannii or Candida spp. are isolated from blood cultures. Duration of therapy depends on the immunological recovery of the patient, the pathogen isolated and the presence of related complications, such as thrombosis, pneumonia, endocarditis and osteomyelitis. Antibiotic lock techniques in addition to systemic treatment are beneficial for Gram-positive infections. Although prospectively controlled studies are lacking, the concomitant use of urokinase locks and taurolidine secondary prophylaxis seem to favour catheter salvage.

Infections associated with medical devices: pathogenesis, management and prophylaxis

The insertion or implantation of foreign bodies has become an indispensable part in almost all fields of medicine. However, medical devices are associated with a definitive risk of bacterial and fungal infections. Foreign body-related infections (FBRIs), particularly catheter-related infections, significantly contribute to the increasing problem of nosocomial infections. While a variety of micro-organisms may be involved as pathogens, staphylococci account for the majority of FBRIs. Their ability to adhere to materials and to promote formation of a biofilm is the most important feature of their pathogenicity. This biofilm on the surface of colonised foreign bodies is regarded as the biological correlative for the clinical experience with FBRI, that is, that the host defence mechanisms often seem to be unable to handle the infection and, in particular, to eliminate the micro-organisms from the infected device. Since antibacterial chemotherapy is also frequently not able to cure these infections despite the use of antibacterials with proven in vitro activity, removal of implanted devices is often inevitable and has been standard clinical practice. However, in specific circumstances, such as infections of implanted medical devices with coagulase-negative staphylococci, a trial of salvage of the device may be justified. All FBRIs should be treated with antibacterials to which the pathogens have been shown to be susceptible. In addition to systemic antibacterial therapy, an intraluminal application of antibacterial agents, referred to as the 'antibiotic-lock' technique, should be considered to circumvent the need for removal, especially in patients with implanted long-term catheters. To reduce the incidence of intravascular catheter-related bloodstream infections, specific guidelines comprising both technological and nontechnological strategies for prevention have been established. Quality assurance, continuing education, choice of the catheter insertion site, hand hygiene and aseptic techniques are aspects of particular interest. Furthermore, all steps in the pathogenesis of biofilm formation may represent targets against which prevention strategies may be directed. Alteration of the foreign body material surface may lead to a change in specific and nonspecific interactions with micro-organisms and, thus, to a reduced microbial adherence. Medical devices made out of a material that would be antiadhesive or at least colonisation resistant would be the most suitable candidates to avoid colonisation and subsequent infection. Another concept for the prevention of FBRIs involves the impregnation of devices with various substances such as antibacterials, antiseptics and/or metals. Finally, further studies are needed to translate the knowledge on the mechanisms of biofilm formation into applicable therapeutic and preventive strategies.

Catheter-Related Bloodstream Infections in the Intensive Care Unit Population

Catheter-related bloodstream infections (CRBIs) are a cause of significant morbidity and mortality in intensive care unit patients. Development of CRBIs may occur by several mechanisms. The role of fibrin and biofilm development and their impact on therapy are described. Multiple preventative strategies related to the insertion and maintenance of the catheter site have been identified. Topical antisepsis and use of antibiotic-impregnated catheters are also beneficial for reducing the incidence of CRBI. Antibiotic lock solutionsmay be effective in preventing CRBI for select patients with longterm catheter use. Treatment of CRBIs should be based on suspected organisms, whichmost commonly include staphylococci, gram-negatives, including Pseudomonas aeruginosa andCandida species. Duration of treatment and decisions regarding catheter removal are controversial. Evaluation and treatment of potential complications of CRBIs, including endocarditis, infected thrombophlebitis, osteomyelitis, and endophthalmitis, are essential.

Catheter design influences recurrence of catheter-related bloodstream infection in children with cancer

PURPOSE

Multiple studies have demonstrated that catheter-related bloodstream infections (CRBI) can be successfully treated without catheter removal (in situ therapy), but there is insufficient information available to determine if catheter design can influence the eradication of bacteremia or recurrence.

PATIENTS AND METHODS

Bacteremic episodes in patients at St Jude Children's Research Hospital between January 1996 and May 2001 were identified and patient records were reviewed.

RESULTS

A total of 172 unique episodes of CRBI were identified. In situ therapy resulted in successful eradication of bacteremia in 87% of the episodes. Bacteremia recurred in 10% of the episodes. Although catheter design (Hickman and Broviac versus totally implantable central venous catheter) did not influence short-term eradication of bacteremia, totally implantable central venous catheters were significantly associated with recurrence of bacteremia (odds ratio, 10; 95% confidence interval, 3.1 to 33.3). In a multivariable analysis, this association between catheter design and recurrence remained statistically significant after adjustment for other factors that influenced recurrence in this study (isolation of coagulase-negative staphylococci and inadequate duration of initial antibiotic therapy).

CONCLUSION

This study demonstrates that patients with CRBI with a totally implantable central venous catheter in place are more likely to develop recurrent bacteremia. Management strategies to prevent recurrence in this setting should be explored.

Ethanol-lock technique in the treatment of bloodstream infections in pediatric oncology patients with broviac catheter

PURPOSE

To assess the ethanol-lock technique as a means of treating central venous line infections. Bloodstream infections in patients with tunneled central venous catheters can lead to removal of the lines.

METHODS

Twenty-eight children and adolescents aged 2 to 18 years, with different types of cancer, had Broviac catheters and presented with positive blood culture and clinical signs of infection between January 2000 and December 2001. The ethanol-lock technique was performed 24 times in 18 patients in addition to empiric (initially) and specific (after antibiogram) intravenous antibiotic treatment. In another 15 cases, 13 children were treated with systemic antibiotics alone.

RESULTS

Sixty-seven percent of the patients treated with ethanol locks had no infectious relapse of any kind within 4 weeks of treatment or during subsequent aplasia, compared with 47% treated with systemic antibiotics alone. In one boy the catheter infection could not be cleared with systemic antibiotics alone, but after one course of ethanol locks no more blood culture-positive infectious episodes were observed. No severe clinical side effects of ethanol flush were observed. Mild symptoms that occurred were tiredness, headaches, dizziness, nausea, and light-headedness.

CONCLUSIONS

The ethanol-lock technique appears to be a safe, well tolerated, and effective way to treat central venous line infections, even in small children. A prospective randomized study should be designed to compare antibiotic-lock, ethanol-lock technique, and systemic antibiotics alone in the treatment of device-associated bloodstream infection.

A prospective double-blind randomized trial of urokinase flushes to prevent bacteremia resulting from luminal colonization of subcutaneous central venous catheters

PURPOSE

This study was undertaken to determine if central venous catheter (CVC)-related infection in children with cancer could be prevented by monthly flushing of the catheter with urokinase.

PATIENTS AND METHODS

Between August 1994 and July 1998, 103 patients with cancer were randomized at the time of subcutaneous CVC placement to receive monthly flushing of their catheters with either 5000 IU of urokinase-heparin or heparin alone. Patients subsequently had blood cultures taken from their CVCs during an episode of fever.

RESULTS

Seventy-four of the 103 patients (72%) enrolled in the study received at least 6 catheter flushes: 40 with urokinase-heparin and 34 with heparin. The median number of flushes was 9.5 in the urokinase-heparin group and 10.2 in the heparin-only group (P = 0.62). There were 5 positive blood cultures in the urokinase-heparin group and seven in patients receiving heparin alone (P = 0.27). Staphylococcus epidermidis was isolated from the blood of 3 patients receiving urokinase-heparin and 6 in those receiving heparin alone (P = 0.17).

CONCLUSION

Prophylactic monthly catheter flushes with 5000 IU urokinase did not significantly decrease the number of documented bacteremic events in children with cancer who have CVCs.

Infectious complications of venous access devices

Infection represents one of the most common venous access device (VAD)-related complications requiring catheter removal. Recognition of such complications is essential to provide appropriate therapy in the setting of active infection. This article reviews the definition of various types of infections, as well as reviewing the diagnosis, prevention, and treatment of VAD-related infections.

Synthesis and characterization of a novel biodegradable antimicrobial polymer

Bacterial infection is a frequent complication associated with the use of medical devices. In an effort to address this problem, antibacterial agents have been incorporated or applied directly onto the surfaces of numerous types of medical devices. This study assessed the feasibility of using a novel biodegradable polymer to release antibiotic drugs in response to inflammatory related enzymes. A model drug polymer was synthesized using 1,6-hexane diisocyanate (HDI), polycaprolactone diol (PCL), and a fluoroquinolone antibiotic, ciprofloxacin. Polymers were characterized by size-exclusion chromatography (SEC), and elemental analysis. Biodegradation studies were carried out by incubating the polymers with solutions of cholesterol esterase (CE) or phosphate buffer (pH 7.0) for 30 days at 37 degrees C. The degradation was assessed by high-performance liquid chromatography (HPLC), mass spectrometry (MS) and 14C radiolabel release. Subsequently, the activity of the released antibiotic was assessed against a clinical isolate of Pseudomonas aeruginosa. HPLC analysis showed the release of multiple degradation products which were identified, by tandem MS, to include ciprofloxacin and derivatives of ciprofloxacin. The microbiological assessment showed that the released ciprofloxacin possessed antimicrobial activity; 1 microg/ml was measured after 10 days. The results of this study suggest that these novel bioresponsive antimicrobial polymers or similar analogs show promise for use in the control of medical device associated infections.

Challenge of supportive surgical care in pediatric oncology

The advent of aggressive treatment protocols and the development of new techniques and procedures now require that the pediatric surgeon be an integral part of all aspects of pediatric oncology care. Supportive care issues, rather than primary tumor management decisions, now dominate the pediatric surgeon's experience and range from managing the different types of vascular access devices and their complications to assessing the surgical implications of the toxic complications of current chemotherapy protocols. New treatments such as bone marrow transplantation have presented new challenges to the pediatric surgeon, while new techniques such as minimally invasive surgery have dramatically improved our ability to render compassionate and more effective care to our patients as they undergo these potentially toxic treatment regimens.

Use of urokinase in pediatric hematology/oncology patients

PURPOSE

This study was conducted to determine urokinase use practices in pediatric hematology/oncology centers.

METHODS

Pediatric hematology/oncology centers were surveyed by telephone regarding urokinase use in children with central venous catheters (CVCs).

RESULTS

A total of 92 centers participated in the study. Urokinase is the primary thrombolytic agent used in pediatric hematology/oncology centers; 67 of 92 (73%) centers had a written protocol for its use. Multiple boluses of urokinase were used in most centers; only 16 of 92 (17%) centers limited urokinase use to 1 bolus per episode of CVC occlusion. At 10 of 92 (11%) centers, adverse events (e.g., fever, chills, or bleeding) after urokinase administration were reported. At 83 of 91 (91%) centers, urokinase was routinely used to clear thrombi in children with central nervous system tumors despite contraindications. At 80 of 92 (87%) centers, occluded CVCs were replaced after unsuccessful thrombolytic therapy, but only 21% of the centers altered the CVC maintenance protocol after replacement. Written protocols, the use of multiple boluses, and urokinase infusions were more likely at larger centers (i.e., > 200 patients) than in medium (100-200 patients) or small (< 100 patients) centers.

CONCLUSIONS

Urokinase is a widely used alternative to replacement of occluded CVCs, but protocols very widely. Indiscriminate urokinase use can be expensive and potentially hazardous. Centers that use urokinase should have standardized protocols, monitor use and adverse effects, and periodically review efficacy data.

Risk factors for early infection of central venous catheters in pediatric patients

BACKGROUND

In an effort to avoid infections that can lead to the premature removal of indwelling central venous catheters (CVCs), the surgical technique and host factors present in pediatric recipients of permanent CVCs were reviewed.

STUDY DESIGN

All patients receiving CVCs over a 17-month period were identified. Those patients with fever and positive blood cultures drawn through the CVC within 45 days of line placement were labeled as having early infection. A case-control design was used to select two control patients for each infected patient. Charts from both the infection and control groups were reviewed for several factors present at the time of CVC placement, including fever, neutropenia (absolute neutrophil count [ANC] < 500 and ANC < 1,000), use of perioperative antibiotics, diagnosis, CVC site, and type of CVC. Chi-square test with Yates correction was used to compare the groups. Odds ratios (ORs) and 95% confidence intervals were derived.

RESULTS

Among the 473 CVCs placed, early infections developed in 53 patients (12%). The control group consisted of 106 patients. Neutropenia was present in 16 of 53 infected patients versus 8 of 106 controls (p = 0.004, OR = 5.30). Perioperative antibiotics were given to 25 of 53 infected patients versus 72 of 106 controls (p = 0.02, OR = 0.42). Fever was present in 12 of 53 infected patients versus 14 of 106 controls (p = 0.19, OR = 1.92). Factors that were equally prevalent between the groups and that did not appear to influence the CVC infection rate included a diagnosis of malignancy, CVC type, and site of placement. Of the 53 infected catheters, 16 (30%) could not be cleared of infection and were removed.

CONCLUSIONS

This study documents that neutropenia and failure to administer prophylactic antibiotics are risk factors for the development of early CVC infection in pediatric patients. To avoid early infection and possible premature CVC removal, we recommend that placement of permanent CVCs be postponed until the ANC is > 1,000. Perioperative antibiotics should be given. A trend toward higher infection rates was seen in patients with preoperative fever.

Catheter-related complications of cancer therapy

Although the management of CVC-related infection appears complex and at times the literature seems to be contradictory, simple guidelines can direct the clinician in a stepwise fashion. Knowledge of the pathogenesis of each organism and the immune status of the host is crucial to decide whether catheter removal or retention is indicated. For example, in general, GNB bacteremia does not immediately prompt catheter removal in a neutropenic patient but does in a nonneutropenic host because of the gastrointestinal source of the former and a primary catheter source in the latter. In summary, as more CVCs are inserted in patients undergoing chemotherapeutic, antimicrobial, transfusional, and nutritional supportive care, novel approaches to prevention and treatment of the associated infectious complications inherent with such devices are needed. A multifaceted approach from impregnated catheters to local catheter-site antisepsis was reviewed. We may find, however, that as simple handwashing between patients is crucial to infection control, so too is a trained catheter-care team using total barrier precautions and ensuring proper local catheter maintenance critical to preventing CVC-related infections.

Urokinase in the treatment of bacteremia and candidemia in patients with right atrial catheters

BACKGROUND

Urokinase plasminogen activator was used in combination with antibiotic therapy given through the catheter to improve the treatment of right atrial catheter infections.

METHODS

One hundred fifty-four episodes of bacteremia and candidemia occurring in 97 children with malignant or hematologic conditions were treated. After 24 hours of antibiotic therapy, 1 ml urokinase (5000 units/ml) was instilled, dwelling 1 hour, and then removed; this was repeated within 24 hours. Antibiotic therapy was continued for then removed; this was repeated within 24 hours. Antibiotic therapy was continued for 10 to 35 days. Administration of urokinase was repeated once if infection recurred within 8 weeks of initial treatment.

RESULTS

There were no adverse affects from administration of urokinase. Bacteremia clearance failed after initial administration of urokinase in 12 episodes; this failure was mostly associated with the presence of gram-positive organisms. Blood culture results remained positive in three cases after repeat therapy. Bacteremia recurred in 15 of 125 episodes; in three cases bacteremia did not clear after repeat administration of urokinase or recurred again. Recurrence was lowest for gram-negative organisms and Candida sp. Less than 5% of catheters were removed as a result of treatment failure.

CONCLUSIONS

Administration of urokinase combined with antibiotic therapy is safe and may be effective in treating bacteremia and candidemia in patients with right atrial catheters. Use of urokinase may improve treatment of organisms that are otherwise difficult to control and may prevent recurrence of infection.

Prevention of biofilm formation by polymer modification

Bacterial biofilm formation on synthetic polymers plays an important role in industry and in modern medicine, leading, for example, to difficult-to-treat infections caused by colonized foreign bodies. Prevention of biofilm formation is a necessary step in the successful prophylaxis of such infections. One approach is to inhibit bacterial adherence by polymer surface modification. We have investigated polymer modification by glow discharge treatment in order to study the influence of the modified surface on bacterial adherence. Surface roughness, surface charge density and contact angles of the modified polymers were determined and related to the adherence of Staphylococcus epidermidis KH6. Although no influence of surface roughness and charge density on bacterial adherence was noticed, a correlation between the free enthalpy of adhesion (estimated from contact angle measurements) and adherence was observed. There seems to exist a certain minimum bacterial adherence, independent of the nature of the polymer surface. Modified polymers with negative surface charge allow for bacterial adherence close to the adherence minimum. These polymers could be improved further by the ionic bonding of silver ions to the surface. Such antimicrobial polymers are able to prevent bacterial colonization, which is a prerequisite for biofilm formation. It is suggested that modification of polymers and subsequent surface coupling of antimicrobials might be an effective approach for the prevention of bacterial biofilm formation.

Management of infection and occlusion associated with vascular access devices

OBJECTIVE

To provide an overview of the etiology, assessment, diagnosis, and management of infections and occlusions that occur with venous access devices (VADs).

CONCLUSIONS

The two major complications of VADs are infections and occlusions. Several strategies have been attempted to prevent and treat infections and occlusions; however, one specific method has yet to be determined. As a result, major controversies exist regarding the best method to manage these complications. Controlled randomized studies are needed to examine each type of VAD in relation to preventive and treatment strategies.

IMPLICATIONS FOR NURSING PRACTICE

Preservation of VADs demands the development of and adherence to specific guidelines for maintenance care as well as an awareness of the incidence, presentation, and management of complications. Clearly, prevention is the key to effective management of infection and occlusion associated with VADs. Nurses must be familiar with institutional policies and procedures for the care of VADs.