Outcomes of therapy: vancomycin-resistant enterococcal bacteremia in hematology and bone marrow transplant patients

Daptomycin-Resistant Enterococcus Bacteremia Is Associated with Prior Daptomycin Use and Increased Mortality after Liver Transplantation

Background

Risk factors for acquisition of vancomycin-resistant Enterococcus (VRE) include immunosuppression, antibiotic exposure, indwelling catheters, and manipulation of the gastrointestinal tract, all of which occur in liver transplant recipients. VRE infections are documented in liver transplantation (LT); however, only one single center study has assessed the impact of daptomycin-resistant Enterococcus (DRE) in this patient population.

Methods

We conducted a retrospective multicenter cohort study comparing liver transplant recipients with either VRE or DRE bacteremia. The primary outcome was death within 1 year of transplantation. Multivariable logistic regression analyses were performed to calculate adjusted odds ratios for outcomes of interest.

Results

We identified 139 cases of Enterococcus bacteremia following LT, of which 78% were VRE and 22% were DRE. When adjusted for total intensive care unit days in the first transplant year, liver-kidney transplantation, and calcineurin inhibitor use, patients with DRE bacteremia were 2.65 times more likely to die within 1 year of transplantation (adjusted odds ratio [aOR], 2.648; 95% CI, 1.025–6.840; P = .044). Prior daptomycin exposure was found to be an independent predictor of DRE bacteremia (aOR, 30.62; 95% CI, 10.087–92.955; P < .001).

Conclusions

In this multicenter study of LT recipients with Enterococcus bacteremia, DRE bacteremia was associated with higher 1-year mortality rates when compared with VRE bacteremia. Our data provide strong support for dedicated infection prevention and antimicrobial stewardship efforts for transplant patients. Further research is needed to support the development of better antibiotics for DRE and practical guidance focusing on identification and prevention of colonization and subsequent infection in liver transplant recipients at high risk for DRE bacteremia.

Vancomycin-resistant enterococci infection and predisposing factors for infection and mortality in patients with acute leukaemia and febrile neutropenia

BACKGROUND

Vancomycin-resistant enterococcus (VRE) is an infectious agent that can increase morbidity and mortality, especially in patients with neutropenia in haematology departments. We analysed VRE infections and mortality rates among VRE colonized patients with acute leukaemia, defined predisposing risk factors for infection and mortality, and investigated the influence of daptomycin or linezolid treatment on mortality.

PATIENTS-METHODS

We included 200 VRE colonized adult acute leukaemia patients with febrile neutropenia between January 2010 and January 2016. Data were collected from electronic files.

RESULTS

There were 179 patients in the colonized group, and 21 patients in the infected group. Enterococcus faecium (van A) was isolated from all patients. The infection rate was 10.5 %, and the types of infections noted were as follows: bloodstream (n = 14; 66.7 %), skin and soft tissue (n = 3; 14.3 %), urinary (n = 2; 9.5 %), and others (9.5 %). In the multivariate logistic regression analysis, exposure to invasive procedures, coinfection status, and >15 days of VRE positivity were independent risk factors for VRE infections. In hospital mortality rates were 57.1 % in the infected group, and 9.5 % in the colonized group (p < 0.001). Older age, female gender, absolute neutropenia, and coinfection status were statistically significant predictor of survival.

CONCLUSION

Vancomycin-resistant enterococcus infections are associated with high morbidity and mortality in haematology patients with neutropenia. Clinicians should be aware of predisposing risk factors for VRE infection to avoid unfavourable outcomes. We believe that larger studies are necessary regarding the influence of treatment with daptomycin and linezolid.

Epidemiology, treatment and outcomes of bloodstream infection due to vancomycin-resistant enterococci in cancer patients in a vanB endemic setting

Background

Vancomycin-resistant enterococcus (VRE) is an important cause of infection in immunocompromised populations. Few studies have described the characteristics of vanB VRE infection. We sought to describe the epidemiology, treatment and outcomes of VRE bloodstream infections (BSI) in a vanB predominant setting in malignant hematology and oncology patients.

Methods

A retrospective review was performed at two large Australian centres and spanning a 6-year period (2008–2014). Evaluable outcomes were intensive care admission (ICU) within 48 h of BSI, all-cause mortality (7 and 30 days) and length of admission.

Results

Overall, 106 BSI episodes were observed in 96 patients, predominantly Enterococcus faecium vanB (105/106, 99%). Antibiotics were administered for a median of 17 days prior to BSI, and 76/96 (79%) were neutropenic at BSI onset. Of patients screened before BSI onset, 49/72 (68%) were found to be colonised. Treatment included teicoplanin (59), linezolid (6), daptomycin (2) and sequential/multiple agents (21). Mortality at 30-days was 31%. On multivariable analysis, teicoplanin was not associated with mortality at 30 days.

Conclusions

VRE BSI in a vanB endemic setting occurred in the context of substantive prior antibiotic use and was associated with high 30-day mortality. Targeted screening identified 68% to be colonised prior to BSI. Teicoplanin therapy was not associated with poorer outcomes and warrants further study for vanB VRE BSI in cancer populations.

Observational retrospective single-centre study in Japan to assess the clinical significance of serum daptomycin levels in creatinine phosphokinase elevation

WHAT IS KNOWN AND OBJECTIVE

Daptomycin-induced creatinine phosphokinase (CPK) elevation is reported to be associated with its trough level (C_trough ; breakpoint of 24.3 μg/mL). However, even with high-dose treatment (ie, > 8 mg/kg), the safety of daptomycin treatment is widely demonstrated with low or no significant incidence of CPK elevation or other adverse effects, despite the possibility of C_trough above 24.3 μg/mL. Therefore, we questioned the clinical significance of C_trough levels of 24.3 μg/mL. In this study, we retrospectively evaluated the significance of C_trough in the clinical setting, in addition to completing a retrospective safety assessment of daptomycin utilizing electronic health records.

METHODS

Patients who had received daptomycin treatment for > 4 days from July 2011 to June 2015 were enrolled. Serum daptomycin levels, including C_trough and peak (C_peak ), were measured by high-performance liquid chromatography equipped with a photodiode array. To evaluate the safety, patients' characteristics and relevant laboratory test values were reviewed retrospectively using an electronic medical record system.

RESULTS AND DISCUSSION

A total of 52 therapeutic cases for 46 patients were identified; of these, C_trough and C_peak levels were measured in 27 and 28 cases, respectively, and 6 patients received multiple courses of daptomycin treatment. The median age of the 52 patients was 68 years (range: 19-88 years), and 14 patients initially had an estimated creatinine clearance of less than 30 mL/min. Seven cases indicated a C_trough of above 24.3 μg/mL; however, none of these presented CPK elevation, which meets with the study definition for abnormality. Furthermore, of the two patients with abnormal CPK elevations, only one patient had a measured C_trough (of 10.9 μg/mL). Their CPK abnormalities were temporal and did not result in treatment discontinuation. The other four patients discontinued daptomycin treatment due to suspicions of adverse effects. Of the discontinued patients, two had measured C_trough levels; these were 8.6 and 8.1 μg/mL. All patients with abnormal CPK elevation or treatment discontinuation exhibited C_trough levels lower than 24.3 μg/mL. In this study, two patients receiving high-dose daptomycin (ie, 9.4 and 10.0 mg/kg) had observed C_trough levels similar to patients who received doses of daptomycin < 9 mg/kg.

WHAT IS NEW AND CONCLUSIONS

The safety of daptomycin treatment was suggested in this study. C_trough level of 24.3 μg/mL was not suggested as a significant clinical index for the incidence of CPK elevation, adverse effects or treatment discontinuation. Thus, acceptable tolerability towards higher C_trough levels than 24.3 μg/mL was also suggested, though further studies are required. On the other hand, low levels of daptomycin in blood were unexpectedly observed in two cases, despite the high-dose treatments. Accordingly, the monitoring of serum daptomycin levels may also be useful to assess cases in which subtherapeutic levels were achieved.

Vancomycin-resistant Enterococcus in solid organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation address vancomycin-resistant enterococci (VRE) infections in SOT candidates and recipients. VRE are an important cause of infection and have been named by the CDC as a serious public threat. Typically, a commensal of the gastrointestinal tract, VRE may become pathogenic after abdominal organ manipulation like transplantation. This guideline reviews the microbiology, antimicrobial resistance mechanisms, epidemiology, and clinical manifestations of VRE infection in the context of solid organ transplantation. Treatment regimens including combination therapies and novel investigational agents are also reviewed. Finally, an updated appraisal of infection control measures relevant to VRE infection and colonization is presented.

Vancomycin-resistant enterococcus infection in the hematopoietic stem cell transplant recipient: an overview of epidemiology, management, and prevention

Vancomycin-resistant enterococcus (VRE) is now one of the leading causes of nosocomial infections in the United States. Hematopoietic stem cell transplantation (HSCT) recipients are at increased risk of VRE colonization and infection. VRE has emerged as a major cause of bacteremia in this population, raising important clinical questions regarding the role and impact of VRE colonization and infection in HSCT outcomes as well as the optimal means of prevention and treatment. We review here the published literature and scientific advances addressing these thorny issues and provide a rational framework for their approach.

Daptomycin nonsusceptible vancomycin resistant Enterococcus bloodstream infections in patients with hematological malignancies: risk factors and outcomes

Daptomycin is typically the treatment of choice for vancomycin resistant Enterococcus (VRE) bloodstream infections (BSI) in patients with hematological malignancies, but increasingly daptomycin nonsusceptible VRE are being reported. We reviewed our experience with daptomycin nonsusceptible VRE BSI among patients with hematological malignancies. We compared risk factors and outcomes of 20 patients with daptomycin nonsusceptible VRE BSI (case patients) with 40 matched control patients with daptomycin susceptible VRE BSI. Case patients had more complications (6/20 vs. 2/40, p = .013); all-cause mortality was similar in both groups. By multivariable analysis, only prior daptomycin exposure within 90 days was significantly associated with daptomycin nonsusceptible VRE BSI (odds ratio 26.71; p < .0001). In 25% of case patients, all of whose VRE isolates had an initial minimum inhibitory concentration (MIC) of 4 μg/mL, nonsusceptibility developed during treatment, raising the question of whether higher doses of daptomycin should be used for VRE BSI in hematology patients.

Daptomycin versus linezolid for the treatment of vancomycin-resistant enterococcal bacteraemia: implications of daptomycin dose

Treatment options for vancomycin-resistant enterococci (VRE) bloodstream infection are limited. Studies comparing daptomycin or linezolid in treating VRE bloodstream infection have conflicting results and suggest daptomycin underdosing. The responses to different daptomycin doses have not been studied. We conducted a multicentre prospective cohort study to compare linezolid and daptomycin (≥6 mg/kg) for the treatment of VRE bloodstream infection. The primary outcome was 14-day mortality. We used multivariate logistic regression analysis for outcome analysis and a generalized additive model for dose-dependent response estimation. Two hundred twelve patients were included (daptomycin, n = 141; linezolid, n = 71). All-cause 14-day mortality was higher in the daptomycin group (36.9% vs. 21.1%; p 0.03). After adjusting for confounders in logistic regression, mortality was lower in the linezolid group (adjusted odds ratio (aOR), 0.45; 95% confidence interval (CI), 0.21-0.96; p 0.04). The generalized additive model showed that higher-dose daptomycin (≥9 mg/kg) was associated with better survival than lower-dose daptomycin (6-9 mg/kg). Logistic regression showed that linezolid (aOR, 0.36; 95% CI, 0.17-0.79; p 0.01) and higher-dose daptomycin (aOR, 0.26; 95% CI, 0.09-0.74; p 0.01) independently predicted lower mortality compared to lower-dose daptomycin. Linezolid was not superior to higher-dose daptomycin in terms of mortality (aOR, 1.40; 95% CI, 0.45-4.37; p 0.57). Higher-dose daptomycin had lower mortality than lower-dose daptomycin. Despite higher mortality for lower-dose daptomycin than linezolid, linezolid conferred no survival benefit compared to higher-dose daptomycin. Our findings suggest that the recommended daptomycin dose is suboptimal for treating VRE bacteraemia.

The prevention and management of infections due to multidrug resistant organisms in haematology patients

Infections due to resistant and multidrug resistant (MDR) organisms in haematology patients and haematopoietic stem cell transplant recipients are an increasingly complex problem of global concern. We outline the burden of illness and epidemiology of resistant organisms such as gram-negative pathogens, vancomycin-resistant Enterococcus faecium (VRE), and Clostridium difficile in haematology cohorts. Intervention strategies aimed at reducing the impact of these organisms are reviewed: infection prevention programmes, screening and fluoroquinolone prophylaxis. The role of newer therapies (e.g. linezolid, daptomycin and tigecycline) for treatment of resistant and MDR organisms in haematology populations is evaluated, in addition to the mobilization of older agents (e.g. colistin, pristinamycin and fosfomycin) and the potential benefit of combination regimens.

Invasive gram-positive bacterial infection in cancer patients

Systematic studies have shown that gram-positive organisms are the leading cause of invasive bacterial disease in patients with cancer. A broad range of gram-positive bacteria cause serious infections in the cancer patient with the greatest burden of disease being due to staphylococci, streptococci, and enterococci. The evolution of cancer therapy and the changing epidemiology of major gram-positive pathogens mean that ongoing efforts are needed to understand and mitigate the impact of these bacteria in patients with malignancy. The development of novel antibacterials, optimization of treatment approaches, implementation of improved vaccines, and manipulation of the microbiome are all active areas of investigation in the goal of improving the survival of the cancer patient through amelioration of the disease burden of gram-positive bacteria.

Clinical Outcomes of Daptomycin for Vancomycin-resistant Enterococcus Bacteremia

PURPOSE

In light of recent evidence suggesting enhancement of daptomycin activity against vancomycin-resistant Enterococcus (VRE) by ampicillin and other β-lactam antibiotics, we evaluated the safety profile and clinical efficacy of daptomycin with and without concomitant β-lactam antimicrobials in the treatment of VRE (faecium or faecalis) bacteremia from multiple centers across the United States.

METHODS

Data were collected retrospectively as part of a larger multicenter registry (The Cubicin Outcomes Registry and Experience). Efficacy and clinical outcomes in patients with VRE bacteremia who received at least 3 days of daptomycin with or without concomitant β-lactams were analyzed. Although all the cases involved daptomycin-susceptible VRE, additional analysis was performed to examine whether the adjunctive β-lactam would play a more pivotal role in cases where the daptomycin MIC was in the upper limit of the susceptibility range, indicating that daptomycin monotherapy efficacy may be relatively compromised compared with cases with lower daptomycin MICs.

FINDINGS

Two hundred sixty-two patients from 33 hospitals were evaluated. Most patients had at least one significant comorbidity, such as solid-organ or bone marrow transplantation (16%), neutropenia (36%), dialysis dependency (20%), or critical illness (36%) requiring care in an intensive care unit. Overall treatment success was 86% (n = 225/262), and treatment success for patients taking concomitant β-lactams was 86% (n = 105/122). Logistic regression identified treatment failure to be associated with sepsis (odds ratio = 3.42; P = 0.009) and an elevated daptomycin MIC (3-4 µg/mL) (odds ratio = 3.23, P = 0.013). No significant increase in clinical failure was seen among patients with elevated daptomycin MIC who received concomitant β-lactam therapy (clinical success, 88% vs 79% for MIC ≤2 vs 3-4 µg/mL, respectively; P = 0.417). Of 262 patients, 33 (13%) experienced ≥1 adverse event possibly related to daptomycin (increased creatine kinase in 8 patients).

IMPLICATIONS

Overall, daptomycin was effective and well tolerated for VRE bacteremia, with lower effectiveness noted with daptomycin MIC of 3 to 4 µg/mL. Concomitant β-lactam therapy with daptomycin may improve clinical outcomes in this setting. Further studies are needed to characterize the potential benefit of concomitant β-lactams with daptomycin.

Empiric use of linezolid in febrile hematology and hematopoietic stem cell transplantation patients colonized with vancomycin-resistant Enterococcus spp

OBJECTIVES

We conducted a retrospective study on the impact of the empiric use of linezolid on mortality in vancomycin-resistant Enterococcus spp (VRE)-colonized hematology and hematopoietic stem cell transplantation (HSCT) patients.

METHODS

VRE-colonized inpatients for whom complete data were available (n=100) were divided into two groups: those who received empiric linezolid in the course of fever refractory to broad-spectrum antibiotics, replacing the glycopeptide utilized for the previous 48 h, and those who did not (control group). All patients were followed until hospital discharge or death. The impact of linezolid and risk factors for all-cause mortality were evaluated; variables with p<0.10 were analyzed in a multivariate model. A Kaplan-Meier survival analysis was done to compare survival among febrile patients colonized by VRE who received empiric linezolid with patients who did not receive linezolid.

RESULTS

Patients empirically prescribed linezolid were generally younger (median age 33 vs. 44 years; p=0.008) and more likely to be recipients of an allogeneic HSCT (24 (68.6%) vs. 24 (36.9%); p=0.009) than patients who did not receive the drug. Fourteen (21.5%) VRE bloodstream infections were diagnosed, all in patients who did not receive empiric linezolid (p=0.002). In-hospital mortality was comparable in empiric linezolid and non-linezolid users (19 (54.3%) vs. 27 (41.5%), respectively; p=0.293). The Kaplan-Meier survival analysis showed no significant difference in survival comparing the group that received linezolid to the group that did not (p=0.72). Graft-versus-host disease (GVHD; odds ratio (OR) 5.90, 95% confidence interval (CI) 1.46-23.79; p=0.012) and persistence of neutropenia (OR 6.93, 95% CI 1.72-27.94; p=0.0065) were independent predictors of all-cause in-hospital death in HSCT patients, and persistence of neutropenia in non-HSCT patients (OR 8.12, 95% CI 1.22-53.8; p=0.030).

CONCLUSIONS

The empiric use of linezolid in VRE-colonized hematology patients had no impact on mortality, which appeared rather to be associated with the persistence of neutropenia in general and GVHD in the HSCT group.

Daptomycin versus linezolid for treatment of vancomycin-resistant enterococcal bacteremia: systematic review and meta-analysis

Background

Linezolid, which has bacteriostatic activity, is approved for the treatment of vancomycin-resistant enterococci (VRE) infections. Meanwhile, daptomycin exerts bactericidal activity against VRE, but is not approved for the treatment of VRE bacteremia. Only a few studies with small sample sizes have compared the effectiveness of these drugs for treatment of VRE bacteremia.

Methods

PubMed, EMBASE, and the Cochrane Library were searched for studies of VRE bacteremia treatment published before January 1, 2014. All studies reporting daptomycin and linezolid treatment outcomes simultaneously were included. The endpoints were mortality and microbiological cure. The adjusted odds ratios (aORs) of mortality in daptomycin- and linezolid-treated patients were extracted if available. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for all outcomes using a random-effects model.

Results

Thirteen studies (532 patients receiving daptomycin, 656 patients receiving linezolid) met the selection criteria. All studies had retrospective cohort designs and relatively small sample sizes. Eight studies compared the aORs of mortality in daptomycin- and linezolid-treated patients. Four studies were published as conference papers and there was significant heterogeneity among these studies (I² = 63%, p = 0.04). Daptomycin use was not associated with better microbiological cure (daptomycin vs. linezolid, OR: 0.67, 95% CI: 0.42–1.06, p = 0.09). However, mortality was higher in patients receiving daptomycin (OR: 1.43, 95% CI: 1.09–1.86, p = 0.009). Subgroup analysis of studies that reported aORs indicated that daptomycin was associated with higher mortality (OR: 1.59, 95% CI: 1.02–2.50, p = 0.04). There was no evidence of publication bias, but all enrolled studies were retrospective, had small sample sizes, and had substantial limitations.

Conclusions

Although limited data is available, the current meta-analysis shows that linezolid treatment for VRE bacteremia was associated with a lower mortality than daptomycin treatment. However, the results should be interpreted cautiously because of limitations inherent to retrospective studies and the high heterogeneity among studies. A large randomized trial is needed to confirm the present results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0687-9) contains supplementary material, which is available to authorized users.

Vancomycin-Resistant Enterococcal Bacteremia Pharmacotherapy

Objective: To review the literature on the pharmacotherapy of bloodstream infections (BSI) caused by vancomycin-resistant enterococci (VRE). Data Sources: A MEDLINE literature search was performed for the period 1946 to May 2014 using the search terms Enterococcus, enterococci, vancomycin-resistant, VRE, bacteremia, and bloodstream infection. References were also identified from selected review articles. Study Selection and Data Extraction: English-language case series, cohort studies, and meta-analyses assessing the options in the pharmacotherapy of VRE BSIs in adult patients were evaluated. Data Synthesis: Studies were identified that utilized linezolid, quinupristin/dalfopristin (Q/D), and daptomycin. In all, 8 comparative retrospective cohort studies, 2 meta-analyses of daptomycin and linezolid, and 3 retrospective comparisons of linezolid and Q/D were included for review. Mortality associated with VRE BSIs was high across studies, and the ability to determine differences in outcomes between agents was confounded by the complex nature of the patients included. Two meta-analyses comparing daptomycin with linezolid for VRE BSIs found modest advantages for linezolid, but these conclusions may be hampered by heterogeneity within the included studies. Conclusions: VRE BSIs remain a difficult-to-treat clinical situation. Differences in toxicity between the agents used to treat it are clear, but therapeutic differences are more difficult to discern. Meta-analyses suggest that a moderate advantage for linezolid over daptomycin may exist, but problems with the nature of studies that they included make definitive conclusions difficult.

Assessing outcomes of adult oncology patients treated with linezolid versus daptomycin for bacteremia due to vancomycin-resistant Enterococcus

Background

The incidence and severity of vancomycin-resistant Enterococcus blood stream infections continue to rise and is a significant burden in the healthcare setting. Literature thus far is minimal regarding treatment outcomes in patients with malignancy and vancomycin-resistant Enterococcus bacteremia. Appropriate antibiotic selection is vital to treatment success due to high rates of resistance, limited antimicrobials and mortality in this patient population. We conducted this study to determine whether treatment outcomes differed between cancer patients treated with linezolid and those treated with daptomycin for vancomycin-resistant Enterococcus bacteremia.

Methods

This single-center, retrospective study included adult patients hospitalized on the oncology service with documented vancomycin-resistant Enterococcus faecium or Enterococcus faecalis bacteremia who received at least 48 h of either linezolid or daptomycin as primary treatment.

Results

A total of 65 patients were included in the analysis. Thirty-two patients received daptomycin as primary treatment, and 33 patients received linezolid as primary treatment. Twenty-six (76.5%) patients in the linezolid cohort versus 22 (71%) patients in the daptomycin cohort achieved microbiological cure ( p = 0.6141). Median length of stay in days (30 vs. 42, p = 0.0714) and mortality (7/32 (20.6%) vs. 8/33 (25.8%), p = 0.6180) were also similar between the linezolid and daptomycin treated patients, respectively.

Conclusion

No differences in microbiological cure, length of stay or mortality were identified between the groups. This study suggests that linezolid and daptomycin are each reasonable options for treating vancomycin-resistant Enterococcus bacteremia in oncology patients. Further prospective, randomized controlled trials are needed to assess the optimal treatment for vancomycin-resistant Enterococcus bacteremia in this patient population.

Daptomycin for the treatment of bacteraemia due to vancomycin-resistant enterococci

Treatment of severe infections caused by vancomycin-resistant enterococci (VRE) is challenging due to the scarcity of reliable therapeutic alternatives. In this context, daptomycin (DAP), a lipopeptide antibiotic, has emerged as an interesting alternative as it is one of the few compounds that retain in vitro bactericidal activity against VRE isolates, although it has not been approved for this purpose by regulatory agencies. In this review, we will summarise the clinical, animal and in vitro evidence evaluating the efficacy of DAP for the management of deep-seated VRE infections. In addition, we will address important clinical concerns such as the emergence of DAP resistance during therapy and reports of therapeutic failure with DAP monotherapy. Finally, we will discuss possible future strategies (such as the use of higher doses and/or combination therapies) to optimise the use of this antibiotic against VRE.

Risk factors for vancomycin-resistant enterococcus bacteremia and its influence on survival after allogeneic hematopoietic cell transplantation

Vancomycin-resistant enterococcus (VRE) is a well-known infectious complication among immunocompromised patients. We performed a retrospective analysis to identify risk factors for the development of VRE bacteremia (VRE-B) within 15 months after allogeneic hematopoietic cell transplantation (alloHCT) and to determine its prognostic importance for other post-transplant outcomes. Eight hundred consecutive adult patients who underwent alloHCT for hematologic diseases from 1997 to 2011 were included. Seventy-six (10%) developed VRE-B at a median of 46 days post transplant. Year of transplant, higher HCT comorbidity score, a diagnosis of ALL, unrelated donor and umbilical cord blood donor were all significant risk factors on multivariable analysis for the development of VRE-B. Sixty-seven (88%) died within a median of 1.1 months after VRE-B, but only four (6%) of these deaths were attributable to VRE. VRE-B was significantly associated with worse OS (hazard ratio 4.28, 95% confidence interval 3.23-5.66, P<0.001) in multivariable analysis. We conclude that the incidence of VRE-B after alloHCT has increased over time and is highly associated with mortality, although not usually attributable to VRE infection. Rather than being the cause, this may be a marker for a complicated post-transplant course. Strategies to further enhance immune reconstitution post transplant and strict adherence to infection prevention measures are warranted.

Multidrug-resistant bacterial infections after liver transplantation: An ever-growing challenge

Bacterial infections are a leading cause of morbidity and mortality among solid organ transplant recipients. Over the last two decades, various multidrug-resistant (MDR) pathogens have emerged as relevant causes of infection in this population. Although this fact reflects the spread of MDR pathogens in health care facilities worldwide, several factors relating to the care of transplant donor candidates and recipients render these patients particularly prone to the acquisition of MDR bacteria and increase the likelihood of MDR infectious outbreaks in transplant units. The awareness of this high vulnerability of transplant recipients to infection leads to the more frequent use of broad-spectrum empiric antibiotic therapy, which further contributes to the selection of drug resistance. This vicious cycle is difficult to avoid and leads to a scenario of increased complexity and narrowed therapeutic options. Infection by MDR pathogens is more frequently associated with a failure to start appropriate empiric antimicrobial therapy. The lack of appropriate treatment may contribute to the high mortality occurring in transplant recipients with MDR infections. Furthermore, high therapeutic failure rates have been observed in patients infected with extensively-resistant pathogens, such as carbapenem-resistant Enterobacteriaceae, for which optimal treatment remains undefined. In such a context, the careful implementation of preventive strategies is of utmost importance to minimize the negative impact that MDR infections may have on the outcome of liver transplant recipients. This article reviews the current literature regarding the incidence and outcome of MDR infections in liver transplant recipients, and summarizes current preventive and therapeutic recommendations.

Daptomycin use in neutropenic patients with documented gram-positive infections

PURPOSE

The goal of this study was to describe the outcomes associated with daptomycin treatment of documented gram-positive infections in patients with neutropenia.

METHODS

All patients with neutropenia (≤500 cells/m(3)) and at least one documented gram-positive culture from 2006-2009 were identified from a retrospective, multicenter, and observational registry (Cubicin(®) Outcome Registry and Experience (CORE(®))). Investigators assessed patient outcome (cured, improved, failed, nonevaluable) at the end of daptomycin therapy. All patients were included in the safety analysis.

RESULTS

The efficacy population had 186 patients; 159 (85 %) patients had either cure (n = 108, 58 %) or improved (n = 51, 27 %) as an outcome. Success rates (cure plus improved) by the lowest WBC during daptomycin were 98/116 (84 %) for ≤100 cells/m(3) and 61/70 (87 %) for 101-499 cells/m(3), P = 0.6. Most patients had cancer; 135/186 (73 %) had hematological malignancy; 26/186 (14 %) had solid tumors, and 9 (5 %) had both. One hundred fifty-six (84 %) patients received other antibiotics before daptomycin treatment; 82 % vancomycin, of which 31 % failed vancomycin. The most common infections were bacteremia (78 %), skin and skin structure infections (8 %), and urinary tract infections/pyelonephritis (6 %). The most common pathogens were vancomycin-resistant Enterococcus faecium (47 %), methicillin-resistant Staphylococcus aureus (20 %), and coagulase-negative staphylococci (19 %). The median (min, max) initial daptomycin dose was 6 mg/kg (3.6, 8.3). The median (min, max) daptomycin duration of therapy was 14 days (1, 86). Possibly related adverse events occurred in 12/209 patients (6 %), and 13 patients (6 %) discontinued daptomycin due to adverse event.

CONCLUSIONS

The results suggest that daptomycin appeared useful and well tolerated in neutropenic patients, and the degree of neutropenia did not affect daptomycin success rates. Comparative clinical trials are needed to confirm these findings.

Systematic review and meta-analysis of linezolid versus daptomycin for treatment of vancomycin-resistant enterococcal bacteremia

Limited therapeutic options exist for the treatment of vancomycin-resistant Enterococcus (VRE) bacteremia; the most commonly used are daptomycin and linezolid. We attempted a systematic review and meta-analysis of the comparative efficacy of those two agents. Studies comparing daptomycin to linezolid treatment for VRE bacteremia, published until August 2012, were identified from the MEDLINE, EMBASE, CENTRAL, ISI Web of Science, and SCOPUS databases. All comparative studies on patients older than 18 years of age that provided mortality data were considered eligible for this systematic review and meta-analysis. Τhe primary outcome of the meta-analysis was 30-day all-cause mortality. Ten retrospective studies including 967 patients were identified. Patients treated with daptomycin had significantly higher 30-day all-cause mortality (odds ratio [OR], 1.61; 95% confidence interval [CI], 1.08 to 2.40) and infection-related mortality (OR, 3.61; 95% CI, 1.42 to 9.20) rates than patients treated with linezolid. When data from all 10 studies were combined, overall mortality was also significantly increased among patients treated with daptomycin (OR, 1.41; 95% CI, 1.06 to 1.89). These findings were confirmed when odds ratios adjusted for potential confounders were pooled. Relapse rates among patients treated with daptomycin were also higher (OR, 2.51; 95% CI, 0.94 to 6.72), although this difference did not reach statistical significance. Adverse event rates were not significantly different between the two groups. Notwithstanding the absence of randomized prospective data, available evidence suggests that mortality rates may be higher with daptomycin than with linezolid among patients treated for VRE bacteremia.

Systematic review and meta-analysis of linezolid and daptomycin for treatment of vancomycin-resistant enterococcal bloodstream infections

Bloodstream infections due to vancomycin-resistant enterococci (VRE-BSI) result in substantial patient mortality and cost. Daptomycin and linezolid are commonly prescribed for VRE-BSI, but there are no clinical trials to determine optimal antibiotic selection. We conducted a systematic review for investigations that compared daptomycin and linezolid for VRE-BSI. We searched Medline from 1966 through 2012 for comparisons of linezolid and daptomycin for VRE-BSI. We included searches of EMBASE, clinicaltrials.gov, and national meetings. Data were extracted using a standardized instrument. Pooled odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using a fixed-effects model. Our search yielded 4,243 publications, of which 482 contained data on VRE treatment. Most studies (452/482) did not present data on BSI or did not provide information on linezolid or daptomycin. Among the remaining 30 studies, 9 offered comparative data between the two agents. None were randomized clinical trials. There was no difference in microbiologic (n = 5 studies, 517 patients; OR, 1.0; 95% CI, 0.4 to 1.7; P = 0.95) and clinical (n = 3 studies, 357 patients; OR, 1.2; 95% CI, 0.7 to 2.0; P = 0.7) cures between the two antibiotics. There was a trend toward increased survival with linezolid compared to daptomycin treatment (n = 9 studies, 1,074 patients; OR, 1.3; 95% CI, 1.1 to 1.8; I(2) = 0 [where I(2) is a measure of inconsistency]), but this did not reach statistical significance (P = 0.054). There are limited data to inform clinicians on optimal antibiotic selection for VRE-BSI. Available studies are limited by small sample size, lack of patient-level data, and inconsistent outcome definitions. Additional research, including randomized clinical trials, is needed before conclusions can be drawn about treatment options for VRE therapy.

Evaluation of the Treatment of Vancomycin-Resistant Enterococcal Urinary Tract Infections in a Large Academic Medical Center

BACKGROUND:

Vancomycin-resistant enterococci (VRE) are a common cause of nosocomial urinary tract infections (UTIs) among hospitalized patients. Clinicians need to differentiate between VRE-associated urinary colonization, asymptomatic bacteriuria, and UTIs to determine the need for treatment and length of therapy.

OBJECTIVE:

To characterize the diagnosis and management of VRE from urinary sources, including compliance with institutional treatment guidelines, and identify risk factors associated with clinical failure.

METHODS:

We performed a retrospective, single-center, cohort study among patients with VRE-positive cultures from urinary sources over a 3-year study period (July 2008-September 2011). Descriptive statistics were used to evaluate demographics, diagnostics, guideline compliance, pharmacotherapy, and outcomes. Risk factors associated with clinical failure were identified by multivariate logistic regression analysis.

RESULTS:

Two hundred sixty-nine distinct episodes of VRE met inclusion criteria among 252 patients. Forty-seven percent and 77% of episodes occurred in patients admitted to an intensive care unit and hospitalized for 7 or more days, respectively. Fifty-eight percent of the episodes were classified as asymptomatic bacteriuria or colonization. Compliance with institutional treatment guidelines for the appropriate drug, dose, and duration occurred in approximately 70% of the cases. Among noncompliant cases (n = 83), 48 (58%) were overtreated, and 35 (42%) were undertreated. Clinical failure among all cases was common, including mortality (17.1%). Factors independently associated with clinical failure determined on multivariate analysis included weight 100 kg or more (OR 5.30; 95% CI 1.42–12.21; p = 0.014), renal disease (OR 2.57; 95% CI 1.02–6.47; p = 0.048), indwelling catheter (OR 4.62; 95% CI 1.05–18.24; p = 0.046), and VRE bloodstream infection (OR 15.71; 95% CI 2.9–128.7; p < 0.001).

CONCLUSIONS:

Improved education is needed to minimize cases of overtreatment and undertreatment of VRE-associated UTIs and decrease inappropriate drug-related costs and clinical failure rates. Risk factors for clinical failure can be used to risk stratify VRE-associated UTIs and further guide treatment decisions.

[Daptomycin in Gram-positive bacterial infections in oncohematological patients and transplant recipients]

Gram-positive infections are a major cause of morbidity and mortality in oncohematological patients and transplant recipients. The most frequently isolated Gram-positive organisms are the coagulase-negative staphylococci, Staphylococcus aureus and Enterococcus spp., and viridans group streptococci. Antibiotic resistance in these organisms is increasing and poses a challenge to clinicians. Daptomycin is rapidly bactericidal against a broad spectrum of gram-positive bacteria, including strains resistant to other drugs. The present article reviews some aspects of Gram-positive infections in these immunocompromised patients and provides a detailed analysis of experience with daptomycin in the treatment of these infections.