Improving diagnosis of central venous catheter-related bloodstream infection by using differential time to positivity as a hospital-wide approach at a cancer hospital

Utility of Differential Time to Positivity in Diagnosing Central Line-Associated Bloodstream Infections: A Systematic Review and Meta-Analysis

BACKGROUND

Differential time to positivity (DTP), defined as pathogen growth at least 2 hours earlier from catheter versus paired peripheral blood cultures, is sometimes used to diagnose central line-associated bloodstream infections (CLABSIs). Previous studies assessing DTP, however, have been small, provided conflicting results, and did not assess heterogeneity across important subgroups.

METHODS

We systematically reviewed the diagnostic characteristics of DTP for CLABSI using MEDLINE, Embase, WoS, CINAHL, LILACS, AMED, and the Cochrane database. Studies were included if they reported sensitivities, specificities, predictive values, likelihood ratios, or 2 × 2 tables of DTP for diagnosing CLABSI. Extracted data were analyzed by using forest plots, bivariate model meta-analysis, and QUADAS-2 quality assessment.

RESULTS

We identified 274 records, of which 23 met the criteria for meta-analysis. Among 2526 suspected CLABSIs, DTP demonstrated a summary sensitivity of 81.3% (95% confidence interval [CI]: 72.8%-87.7%), specificity of 91.8% (95% CI: 84.5%-95.8%), positive likelihood ratio of 9.89 (95% CI: 5.14-19.00), and negative likelihood ratio of 0.20 (95% CI: .14-.30). Covariate analysis based on catheter duration, study design, and patient immune status demonstrated no significant differences. However, DTP performed worse for Staphylococcus aureus (low sensitivity but high specificity) and Candida (high sensitivity but low specificity) compared to other organisms.

CONCLUSIONS

DTP performs well in ruling CLABSIs in or out. Obtaining paired catheter and peripheral blood cultures for DTP when the infectious source is unclear may prevent unnecessary line removal and diagnostic tests. However, this must be balanced against higher contamination rates from catheter cultures.

Usefulness of differential time to positivity between catheter and peripheral blood cultures for diagnosing catheter-related bloodstream infection: Data analysis from routine clinical practice in the intensive care unit

PURPOSE

To assess the accuracy of differential time to positivity (DTP) method for the diagnosis of catheter-related bloodstream infections (CRBSI) in the routine practice of our intensive care unit (ICU).

MATERIALS AND METHODS

Over a five-year study period, ICU patients with a central venous catheter in place for ≥48 h and undergoing DTP test with catheter tip culture were analyzed. We investigated: the accuracy of DTP test with the usual threshold of 120 min in confirming the clinical suspicion of CRBSI; the most accurate threshold value of DTP to detect CRBSI; the diagnostic accuracy of the ratio (rather than the difference) between times to positivity.

RESULTS

Among 278 episodes of paired blood cultures, 13% were CRBSIs. DTP value ≥120 min used for the diagnosis of CRBSI yielded 41% sensitivity and 74% specificity. Performance of DTP values in predicting CRBSI was low (AUC = 0.60 [95%CI: 0.48-0.72]). Cutoff value of the ratio between times to positivity was 0.80, with 46% sensitivity and 79% specificity.

CONCLUSIONS

The routine use of the DTP method at any cutoff point has inadequate accuracy in detecting CRBSI in the real every day clinical practice. Not even the ratio between times to positivity seems to be clinically useful.

Korean Guidelines for Use of Antibiotics for Intra-abdominal Infections in Adults

The guidelines are intended to provide practical information for the correct use of antibiotics for intra-abdominal infections in Korea. With the aim of realizing evidence-based treatment, these guidelines for the use of antibiotics were written to help clinicians find answers to key clinical questions that arise in the course of patient care, using the latest research results based on systematic literature review. The guidelines were prepared in consideration of the data on the causative pathogens of intra-abdominal infections in Korea, the antibiotic susceptibility of the causative pathogens, and the antibiotics available in Korea.

Guidance Statement for the Management of Febrile Neutropenia in Pediatric Patients Receiving Cancer-Directed Therapy in Central America and the Caribbean

PURPOSE

Our objective was to provide regionally appropriate, resource-conscious recommendations for the diagnosis and treatment of pediatric patients with febrile neutropenia.

METHODS

A multinational panel of Central American and Caribbean clinicians who deliver pediatric oncology care prioritized clinically important questions and then used the Grading of Recommendations Assessment, Development and Evaluation methodology to provide recommendations on the selected topics.

RESULTS

Twenty-two questions and 2 definitions were included in the guideline, which was intended to establish minimum care standards for pediatric patients treated in regional centers. Of all the included studies, 6.9% were conducted in low- and middle-income countries, and no studies were performed in countries represented on the panel.

CONCLUSION

The panel made recommendations on the basis of existing evidence but identified important gaps in knowledge from the region and from resource-limited settings that may affect the clinical applicability of these recommendations. These deficiencies suggest a research agenda that will enable future guidelines to be more responsive to the local context.

The effects of TGF-β1 on staphylococcus epidermidis biofilm formation in a tree shrew biomaterial-centered infection model

Background

Transforming growth factor-β1 (TGF-β1) has a wide range of biological functions. It antagonizes lymphocyte response, inhibits pro-inflammatory cytokines, and serves as a signal to turn off the immune response and inflammatory response. To study the correlation between TGF-β1 and T helper (Th)1/Th2 cytokine levels in tree shrews, and to explore the effects of different levels of TGF-β1 on central venous catheter (CVC)-centered Staphylococcus epidermidis biofilm formation in tree shrews.

Methods

Tree shrews were injected with different concentrations of TGF-β1, and venous blood was drawn after 48 h to measure the levels of Th1 and Th2 cytokines. A CVC was placed into the femoral vein, and TGF-β1 at different concentrations and PIA− (ATCC12228) and PIA+ (ATCC35984) standard strains of Staphylococcus epidermidis were injected into the tree shrews to establish a biomaterial-centered infection (BCI) model. After 72 h, the CVC was removed, and biofilm formation was detected using the API bacterial identification system, semi-quantitative biofilm formation assay, and scanning electron microscopy.

Results

In the groups treated with TGF-β1 at different concentrations, the levels of Th1 cytokines interleukin-2 (IL-2), tumor necrosis factor (TNF), and interferon-γ (IFN-γ) were lower than those of normal group, while the levels of Th2 cytokines IL-6, IL-4 and IL-10 were higher than those of normal group. In the TGF-β1 groups at different concentrations, the positive rate of Staphylococcus epidermidis ATCC35984 biofilm formation was higher than that in non-TGF-β1 group, while there was no significant difference in the positive rate of Staphylococcus epidermidis ATCC12228 biofilm formation compared with that of the non-TGF-β1 group.

Conclusions

TGF-β1 causes the imbalance of Th1/Th2 cytokines and Th1/Th2 shift in tree shrews, leading to Th1 cell-led decline in cellular immune function. TGF-β1 promotes PIA+ Staphylococcus epidermidis biofilm formation in the tree shrew BCI model, but it has no significant influence on PIA-Staphylococcus epidermidis biofilm formation on the surface of CVCs.

Should non-bacteraemic patients with a colonized catheter receive antimicrobial therapy?

OBJECTIVES

The impact of antimicrobial therapy on the outcomes of patients with colonized catheters and no bacteraemia has not been assessed. This study assessed whether targeted antibiotic therapy is related to a poor outcome in patients with positive cultures of blood drawn through a non-tunnelled central venous catheter (CVC) and without concomitant bacteraemia.

METHODS

This was a retrospective study involving adult patients with positive blood cultures drawn through a CVC and negative peripheral vein blood cultures. Patients were classified into two groups: those with clinical improvement and those with a poor outcome. These two groups were compared. The outcome was considered poor in the presence of one or more of the following: death, bacteraemia or other infection due to the same microorganism, and evidence of catheter-related bloodstream infection.

RESULTS

A total of 100 patients were included (31 with a poor outcome). The only independent predictors of a poor outcome were a McCabe and Jackson score of 1-2 and a median APACHE score of 5. No association was found between the use of targeted antimicrobial therapy and a poor outcome when its effect was adjusted for the rest of the variables.

CONCLUSIONS

This study showed that antimicrobial therapy was not associated with a poor outcome in non-bacteraemic patients with positive blood cultures drawn through a CVC.

Guideline for the Management of Fever and Neutropenia in Children With Cancer and Hematopoietic Stem-Cell Transplantation Recipients: 2017 Update

Purpose To update a clinical practice guideline (CPG) for the empirical management of fever and neutropenia (FN) in children with cancer and hematopoietic stem-cell transplantation recipients. Methods The International Pediatric Fever and Neutropenia Guideline Panel is a multidisciplinary and multinational group of experts in pediatric oncology and infectious diseases that includes a patient advocate. For questions of risk stratification and evaluation, we updated systematic reviews of observational studies. For questions of therapy, we conducted a systematic review of randomized trials of any intervention applied for the empirical management of pediatric FN. The Grading of Recommendation Assessment, Development and Evaluation approach was used to make strong or weak recommendations and to classify levels of evidence as high, moderate, low, or very low. Results Recommendations related to initial presentation, ongoing management, and empirical antifungal therapy of pediatric FN were reviewed; the most substantial changes were related to empirical antifungal therapy. Key differences from our 2012 FN CPG included the listing of a fourth-generation cephalosporin for empirical therapy in high-risk FN, refinement of risk stratification to define patients with high-risk invasive fungal disease (IFD), changes in recommended biomarkers and radiologic investigations for the evaluation of IFD in prolonged FN, and a weak recommendation to withhold empirical antifungal therapy in IFD low-risk patients with prolonged FN. Conclusion Changes to the updated FN CPG recommendations will likely influence the care of pediatric patients with cancer and those undergoing hematopoietic stem-cell transplantation. Future work should focus on closing research gaps and on identifying ways to facilitate implementation and adaptation.

Surveillance of bloodstream infections in pediatric cancer centers - what have we learned and how do we move on?

Pediatric patients receiving conventional chemotherapy for malignant disease face an increased risk of bloodstream infection (BSI). Since BSI may represent an acute life-threatening event in patients with profound immunosuppression, and show further negative impact on quality of life and anticancer treatment, the prevention of BSI is of paramount importance to improve and guarantee patients' safety during intensive treatment. The great majority of all pediatric cancer patients (about 85%) have a long-term central venous access catheter in use (type Broviac or Port; CVAD). Referring to the current surveillance definitions a significant proportion of all BSI in pediatric patients with febrile neutropenia is categorized as CVAD-associated BSI. This state of the art review summarizes the epidemiology and the distinct pathogen profile of BSI in pediatric cancer patients from the perspective of infection surveillance. Problems in executing the current surveillance definition in this patient population are discussed and a new concept for the surveillance of BSI in pediatric cancer patients is outlined.

Neutropenia in the Febrile Child

Fever in the pediatric population is a common chief complaint presenting to the emergency department and may be one of the first indications of a life-threatening infection, especially in patients with neutropenia. Given that pediatric patients with febrile neutropenia frequently present to emergency departments for emergent care, it is critical for emergency medicine physicians and pediatricians and family physicians working in the emergency department to know the key aspects of the clinical approach to these patients. This review of the clinical evaluation and treatment of the pediatric patient presenting with fever and confirmed or suspected neutropenia will provide health care providers with the necessary tools to effectively care for this patient population.

Clinical prognostic factors for time to positivity in cancer patients with bloodstream infections

PURPOSE

Time to positivity (TTP) has been used in recent years as a simple and rapid method for the additional characterization of the degree of bacteremia. However, prognostic factors for TTP in cancer patients with bloodstream infections have rarely been studied. The aim of this study was to investigate the clinical factors for TTP involving various isolated organisms in cancer patients.

METHODS

We analyzed 386 episodes of bloodstream infections (BSIs) in patients with or without cancer during a 19 month period. Information on age, gender, tumor type, ICU stay, organisms, multidrug resistance (MDR), TTP and outcome was collected. Multivariate logistic regression analysis was performed.

RESULTS

The mean TTP of Enterobacteriaceae in patients with hepatocellular carcinoma, gastroenterological cancer, and lung cancer was shorter than in non-cancer patients (9.86 ± 3.22, 10.05 ± 3.47, 8.85 ± 2.78 vs 13.11 ± 5.37 h). The mean TTP of nonfermentative bacilli in patients with lung cancer (12.37 ± 5.96 h) and hematologic diseases (8.72 ± 4.21 h) was also shorter than in non-cancer patients (20.74 ± 2.46 h), and the mean TTP of Staphylococcus isolates was significantly different between non-cancer patients (22.06 ± 3.71 h) and hematologic disease patients (11.93 ± 5.44 h). The presence of a benign tumor was a significant prognostic factor for a long TTP only in the Staphylococci group (OR 0.076, 95 % CI 0.014-0.412), according to multivariate analysis. MDR (OR 2.178, 95 % CI 1.196-4.239) was an independent significant predictor in the Enterobacteriaceae group, with a short TTP, and it was also a significant clinical factor for a long TTP in nonfermentative bacilli and the Staphylococci group (OR 5.037, 95 % CI 1.065-23.82; OR 0.167, 95 % CI 0.059-0.474).

CONCLUSION

Time to positivity provides useful diagnostic and prognostic information for the differentiation of frequently isolated organisms. This information may help clinicians to use the correct antibiotics in a timely manner to treat cancer patients with BSIs based on clinical factor analysis.

Importance of blood cultures from peripheral veins in pediatric patients with cancer and a central venous line

BACKGROUND

When an infection is suspected in a child with cancer and a central venous line (CVL), cultures are often only obtained from the CVL and not from a peripheral vein (PV). This study was undertaken to evaluate the importance of concomitant blood cultures from the CVL and a PV.

PROCEDURE

Clinical data and the results of all cultures taken concomitantly from the CVL and a PV were registered prospectively in children admitted with fever from April 2008 to December 2012 at the Department of Pediatrics at Aarhus University Hospital Skejby.

RESULTS

During the study period 654 paired cultures obtained from the CVL and from a PV within two hour of each other were included. A true bloodstream infection (BSI) was registered in 112 episodes. In 20 (17%) out of 112, true BSI growth of a microorganism was detected only in the culture from a PV including seven cases of Escherichia coli and three cases of Staphylococcus aureus. In 52 episodes the same microorganism was cultured from both the CVL and a PV. Twenty-four of these episodes were classified as catheter-related bloodstream infections (CRBSI) using differential time to positivity. In total, 64 (57%) of all true BSI were defined as CRBSI.

CONCLUSIONS

Blood cultures should be obtained from a PV in addition to cultures from CVL at the onset of fever in pediatric patients with cancer in order to maximize the findings of true BSIs. The frequency of CRBSI may be over-estimated if blood cultures are drawn from CVL only.

The safety and efficacy of midlines compared to peripherally inserted central catheters for adult cystic fibrosis patients: a retrospective, observational study

BACKGROUND

Intravenous antibiotics are the cornerstone of treatment for patients with cystic fibrosis (CF). Midlines are a type of vascular access device (VAD) used exclusively in one treatment facility within Australia, most other centres use peripherally inserted central catheters (PICCs).

OBJECTIVE

To ascertain the safety and efficacy of midlines for CF patients receiving intravenous antibiotics.

DESIGN

Retrospective observational.

SETTING

A large, major metropolitan teaching hospital in Adelaide, South Australia.

PARTICIPANTS

Adult patients with a diagnosis of CF, who had a PICC or midline inserted for the commencement of antibiotic therapy during the period 2004-2010 to treat a respiratory exacerbation.

METHODS

Medical records and hospital reports were used to record rates of adverse events and unexpected removal of VADs. The primary outcome was a composite measure of adverse events (catheter-related blood stream infection, deep vein thrombosis, occlusion, pain, infiltration, bleeding, phlebitis, catheter leakage and dislodgement) and whether the VAD was removed unexpectedly.

RESULTS

There were 231 midlines and 97 PICCs inserted into 64 patients (39 male and 25 female; age range 18-47 years old). Presented as per 1000 VAD days, patients with PICCs and midlines had similar rates of adverse events (14 and 11 adverse events per 1000 VAD days, respectively). Unexpected removal was higher for patients with midlines (6.90 per 1000 VAD days) than for PICCs (2.89 per 1000 VAD days). Incident rate ratios (IRRs) showed that patients with midlines and PICCs had similar rates of adverse events (IRR 1.18, P=0.617, CI 0.62-2.22) although the removal rate of patients with midlines was twice that of patients with PICCs (IRR 2.24, P=0.079, CI 0.91-5.56). As an absolute risk there were only 4.09 more cases of removal for patients with midlines per 1000 VAD days than those with PICCs.

CONCLUSIONS

Midlines may be an alternative to PICCs for adult CF patients although further research is required with a larger sample size to enable definitive conclusions.

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.

Predictors of bloodstream infection associated with permanently implantable venous port in solid cancer patients

BACKGROUND

The purpose of this study is to characterize the risk factors of bloodstream infection (BSI) associated with the use of permanent implantable venous ports (Port-A) in solid cancer patients.

METHODS

Solid cancer patients implanted with a Port-A were prospectively observed for the occurrence of Port-A-associated BSI (PABSI), defined as BSI without other identifiable infection foci. A PABSI risk score was developed using the Cox proportional hazards model.

RESULTS

A total of 415 patients were registered; 88 PABSI episodes occurred in 58 patients (incidence1.05 per 1000 catheter-days). All but one patient had stage IV cancer. Independent predictors of PABSI occurrence included neutropenia, total parenteral nutrition (TPN), chronic steroid use, invasive procedures, postoperative antibiotics, and preoperative antibiotics. A PABSI risk score with a cut-off value of 0 (sensitivity 88.5%, specificity 64.3%) was defined for stage IV cancer patients as follows: neutropenia, +1.350; TPN, +1.256; chronic steroid use, +1.947; preoperative antibiotics, -0.970; postoperative antibiotics, +0.959; and invasive procedures, +1.098. The median PABSI-free survival was 4.47 months for patients with scores ≥ 0 but not reached for patients with scores <0 (P < 0.0001).

CONCLUSION

The PABSI risk score can assist in identifying high-risk solid cancer patients and may assist in designing future preventive strategies.

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.

Guideline for the management of fever and neutropenia in children with cancer and/or undergoing hematopoietic stem-cell transplantation

PURPOSE

To develop an evidence-based guideline for the empiric management of pediatric fever and neutropenia (FN).

METHODS

The International Pediatric Fever and Neutropenia Guideline Panel is a multidisciplinary and multinational group composed of experts in pediatric oncology and infectious disease as well as a patient advocate. The Panel was convened for the purpose of creating this guideline. We followed previously validated procedures for creating evidence-based guidelines. Working groups focused on initial presentation, ongoing management, and empiric antifungal therapy. Each working group developed key clinical questions, conducted systematic reviews of the published literature, and compiled evidence summaries. The Grades of Recommendation Assessment, Development, and Evaluation approach was used to generate summaries, and evidence was classified as high, moderate, low, or very low based on methodologic considerations.

RESULTS

Recommendations were made related to initial presentation (risk stratification, initial evaluation, and treatment), ongoing management (modification and cessation of empiric antibiotics), and empiric antifungal treatment (risk stratification, evaluation, and treatment) of pediatric FN. For each recommendation, the strength of the recommendation and level of evidence are presented.

CONCLUSION

This guideline represents an evidence-based approach to FN specific to children with cancer. Although some recommendations are similar to adult-based guidelines, there are key distinctions in multiple areas. Implementation will require adaptation to the local context.

Improved diagnosis of central venous catheter-related bloodstream infections using the HB&L UROQUATTRO™ system

The diagnosis of catheter-related bloodstream infections (CRBSIs) in febrile patients with indwelling central venous catheters (CVCs) needs improvement. To diagnose CRBSIs more efficiently, we have developed a novel culture approach using the catheter tips removed from febrile patients. CVCs and blood cultures from 1,070 patients with only CVC-related infections were obtained over a period of 3 years (January 2009 to December 2011). The CVCs were evaluated by a semi-quantitative catheter culture method according to Maki's method and by our novel method, which is based on the use of the HB&L UROQUATTRO™ system (Alifax, Padova, Italy). Using our new method, 571 (571/1,070) of the infections were confirmed as CRBSIs. The remaining 487 patients had infections that were associated with hematologic malignancies, neutropenia, prior exposure to antibiotics, and a decreased CVC removal rate. Twelve samples were identified as false-positives. The percentage of patients with CRBSIs confirmed using the HB&L UROQUATTRO™ system was 53.36 % versus 34.95 % (p-value 0.004) using Maki's method (374/1,070 CVC Maki-positive samples). Our results indicate that our new culture method allows for an improved CRBSI diagnosis rate. A significant number of tip cultures (18.41 %) tested positive for CRBSIs using our system but were negative when tested using Maki's method. Moreover, the use of the HB&L UROQUATTRO™ system allowed us to significantly reduce diagnosis time; a negative CRBSI diagnosis could be made within 6 h and a positive diagnosis could be made within 22-28 h.

Strategies for catheter-related blood stream infection based on medical course in children receiving parenteral nutrition

PURPOSE

The central venous catheter (CVC) is a useful device for patients requiring parenteral nutrition (PN). However, the risk for catheter-related blood stream infection (CRBSI) is always present. We analyzed the medical course pattern and considered the strategies against febrile events in patients with CVC.

METHODS

Nine patients receiving PN in our institute from January 2009 to December 2010 were reviewed. Statistical analysis was performed with the Mann-Whitney U test. A p value of <0.05 was considered statistically significant.

RESULTS

Eighty-four febrile events were observed. Fifty-six specimens had a positive blood culture, and 52 (93%) specimens were found to be positive in 48 h. The fever dissolved within 48 h in 76 (90%) events after our scheduled treatment. Between the positive and negative blood culture groups, no statistical difference was observed in the count of white blood cell (p = 0.15), the proportion of neutrophils (p = 0.11) and C-reactive protein (p = 0.64). None of the CVCs were removed because of failure to control infection.

CONCLUSION

We recommend the treatment for CRBSI be initiated when patients with CVC develop a high-grade fever, even before exact identification of the cause of infection. The treatment can be corrected after the re-evaluation at 48 h.

Differential time to positivity (DTTP) for the diagnosis of catheter-related bloodstream infection: do we need to obtain one or more peripheral vein blood cultures?

The ideal number of blood samples to be obtained from peripheral veins (PVs) when differential time to positivity (DTTP) is being performed is an unresolved issue and most institutions obtain a single set. Our objective was to assess the number of proven central line-associated bloodstream infection (CLABSI) episodes that would have been recovered if blood had been cultured from one or two PVs. We performed a retrospective study in patients with proven CLABSI in which catheter lumens and two or more PV blood cultures were taken simultaneously. We calculated the number of episodes that would have been recovered if the culture of one or more PV blood cultures had been artificially eliminated. During a period of 4 years, we collected 60 episodes of proven CLABSI. Overall, if one PV culture had been eliminated in patients with two or three PV blood cultures, we would have documented 91.8% (p=0.362) and 96.9% (p>0.999) of episodes, respectively. If we had eliminated two PV blood cultures in patients with three PV blood cultures, 90.8% (p>0.999) of episodes would have been documented. When performing the DTTP technique to confirm CLABSI, a single paired PV blood culture was not associated with a significant number of missed CLABSI episodes.

Update on pathogenesis and diagnosis of intravascular catheter-related infections

Infections associated with the use of intravascular catheters cause a substantial morbidity and mortality. New knowledge in the pathogenesis of catheter related bloodstream infections has led to advances in the prevention and management of these infections. The purpose of the present chapter is to review the most relevant data published recently on pathogenesis and diagnosis of intravascular catheter-related infections. It is focus in four different aspects: a) pathogenesis of catheter-related infections and particularly factors affecting biofilm formation and modulation; b) pathogenesis of intravascular catheter-related infections caused by Staphylococcus lugdunensis; c) news on microbiological diagnosis of catheter-related bacteremia; and d) evaluation of current use of blood cultures in the era of continuous monitoring blood cultures systems.