Enterococcal bacteremia is associated with increased risk of mortality in recipients of allogeneic hematopoietic stem cell transplantation

Comparison of morbidity and mortality after bloodstream infection with vancomycin-resistant versus -susceptible Enterococcus faecium: a nationwide cohort study in Denmark, 2010-2019

The emergence of bloodstream infections (BSI) caused by vancomycin-resistant Enterococci (VRE) has caused concern. Nonetheless, it remains unclear whether these types are associated with an excess risk of severe outcomes when compared with infections caused by vancomycin-susceptible Enterococci (VSE). This cohort study included hospitalized patients in Denmark with Enterococcus faecium-positive blood cultures collected between 2010 and 2019 identified in the Danish Microbiology Database. We estimated 30-day hazard ratio (HR) of death or discharge among VRE compared to VSE patients adjusted for age, sex, and comorbidity. The cohort included 6071 patients with E. faecium BSI (335 VRE, 5736 VSE) among whom VRE increased (2010-13, 2.6%; 2014-16, 6.3%; 2017-19; 9.4%). Mortality (HR 1.08, 95%CI 0.90-1.29; 126 VRE, 37.6%; 2223 VSE, 37.0%) or discharge (HR 0.89, 95%CI 0.75-1.06; 126 VRE, 37.6%; 2386 VSE, 41.6%) was not different between VRE and VSE except in 2014 (HR 1.87, 95% CI 1.18-2.96). There was no interaction between time from admission to BSI (1-2, 3-14, and >14 days) and HR of death (P = 0.14) or discharge (P = 0.45) after VRE compared to VSE, despite longer time for VRE patients (17 vs. 10 days for VSE, P < 0.0001). In conclusion, VRE BSI was not associated with excess morbidity and mortality. The excess mortality in 2014 only may be attributed to improved diagnostic- and patient-management practices after 2014, reducing time to appropriate antibiotic therapy. The high level of mortality after E. faecium BSI warrants further study.

Characteristics of Enterococcus species bloodstream infections among adults with and without onco-hematological malignancies: Experiences from the national center of Hungary

Introduction

Over the past decade, enterococcal bloodstream infection (BSI) shows increasing incidence globally among the elderly and in patients with comorbidities. In this study, we aimed to assess microbiological and clinical characteristics and long-term outcomes of BSIs caused by Enterococcus spp. in adult patients with and without active onco-hematological malignancies hospitalized at a national referral institute.

Methods

A prospective analysis of consecutive enterococcal BSI cases was conducted in the National Institute of Hematology and Infectious Diseases (Budapest, Hungary) between December 2019 and April 2022. We compared characteristics and outcomes at 30-days and 1 year after diagnosis among patients with and without onco-hematological malignancies.

Results

In total, 141 patients were included (median age 68 ± 21 years, female sex 36.9%), 37% (52/141) had active onco-hematological malignancies. The distribution of species was as follows: 50.4% Enterococcus faecalis, 46.1% Enterococcus faecium, 1.4% Enterococcus avium and Enterococcus gallinarum, and 0.7% Enterococcus raffinosus. No statistically significant differences in all-cause mortality rates were observed between patient subgroups at 30 days (32.7 vs. 28.1%; P = 0.57) and 1 year (75.0 vs. 60.7%; P = 0.09).

Conclusion

Enterococcal bloodstream infections yielded a relevant burden of morbidity, but with no statistical difference in long-term outcomes of adult patients with and without active onco-hematological malignancies.

A systematic review on the excess health risk of antibiotic-resistant bloodstream infections for six key pathogens in Europe

BACKGROUND

Antimicrobial resistance is a global threat, which requires novel intervention strategies, for which priority pathogens and settings need to be determined.

OBJECTIVES

We evaluated pathogen-specific excess health burden of drug-resistant bloodstream infections (BSIs) in Europe.

METHODS

A systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, and grey literature for the period January 1990 to May 2022.

STUDY ELIGIBILITY CRITERIA

Studies that reported burden data for six key drug-resistant pathogens: carbapenem-resistant (CR) Pseudomonas aeruginosa and Acinetobacter baumannii, third-generation cephalosporin or CR Escherichia coli and Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium. Excess health outcomes compared with drug-susceptible BSIs or uninfected patients. For MRSA and third-generation cephalosporin E. coli and K. pneumoniae BSIs, five or more European studies were identified. For all others, the search was extended to high-income countries.

PARTICIPANTS

Paediatric and adult patients diagnosed with drug-resistant BSI.

INTERVENTIONS

Not applicable.

ASSESSMENT OF RISK OF BIAS

An adapted version of the Joanna-Briggs Institute assessment tool.

METHODS OF DATA SYNTHESIS

Random-effect models were used to pool pathogen-specific burden estimates.

RESULTS

We screened 7154 titles, 1078 full-texts and found 56 studies on BSIs. Most studies compared outcomes of drug-resistant to drug-susceptible BSIs (46/56, 82.1%), and reported mortality (55/56 studies, 98.6%). The pooled crude estimate for excess all-cause mortality of drug-resistant versus drug-susceptible BSIs ranged from OR 1.31 (95% CI 1.03-1.68) for CR P. aeruginosa to OR 3.44 (95% CI 1.62-7.32) for CR K. pneumoniae. Pooled crude estimates comparing mortality to uninfected patients were available for vancomycin-resistant Enterococcus and MRSA BSIs (OR of 11.19 [95% CI 6.92-18.09] and OR 6.18 [95% CI 2.10-18.17], respectively).

CONCLUSIONS

Drug-resistant BSIs are associated with increased mortality, with the magnitude of the effect influenced by pathogen type and comparator. Future research should address crucial knowledge gaps in pathogen- and infection-specific burdens to guide development of novel interventions.

Post-transplantation cyclophosphamide is associated with increased bacterial infections

Post-transplant cyclophosphamide (PTCy) is increasingly used to reduce graft-versus-host disease after hematopoietic cell transplantation (HCT); however, it might be associated with more infections. All patients who were ≥2 years old, receiving haploidentical or matched sibling donor (Sib) HCT for acute leukemias or myelodysplastic syndrome, and either calcineurin inhibitor (CNI)- or PTCy-based GVHD prophylaxis [Haploidentical HCT with PTCy (HaploCy), 757; Sibling with PTCy (SibCy), 403; Sibling with CNI-based (SibCNI), 1605] were included. Most bacterial infections occurred within the first 100 days; 953 patients (34.5%) had at least 1 infection and 352 patients (13%) had ≥2 infections. Patients receiving PTCy had a greater incidence of bacterial infections by day 180 [HaploCy 46%; SibCy 48%; SibCNI 35%; p < 0.001]. Compared with the SibCNI without infection cohort, 1.99-fold, 3.33-fold, 2.78-fold, and 2.53-fold increased TRM was seen for the HaploCy cohort without infection and HaploCy, SibCy, and SibCNI cohorts with infection, respectively. Bacterial infections increased mortality [HaploCy (HR1.84, 99% CI: 1.45-2.33, p < 0.0001), SibCy cohort (HR,1.68, 99% CI: 1.30-2.19, p < 0.0001), and SibCNI cohort (HR,1.76, 99% CI: 1.43-2.16, p < 0.0001). PTCy was associated with increased bacterial infections regardless of donor, and bacterial infections were associated with increased mortality irrespective of GVHD prophylaxis. Patients receiving PTCy should be monitored carefully for bacterial infections following PTCy.

Incidence, Etiology, Risk Factors, and Outcomes of Bloodstream Infection after a Second Hematopoietic Stem Cell Transplantation

Objective Infections after a second hematopoietic stem cell transplantation (HSCT) occur commonly and are associated with high mortality. However, studies on bloodstream infection (BSI) after a second HSCT are lacking. We therefore evaluated the details of BSI after a second HSCT. Methods We retrospectively evaluated the incidence, etiology, risk factors, and outcomes of BSI after a second HSCT. Patients Fifty-two adult patients with hematological malignancies who underwent allogeneic HSCT, including cord blood transplantation (CBT; n=33), as the second transplantation were enrolled. The second transplantation was limited to allogeneic HSCT. Patients who underwent HSCT for graft failure were excluded. Results The median HSCT interval was 438 (range: 39-3,893) days. Overall, 31 (59.6%) patients received autologous HSCT as the first HSCT. The cumulative incidence of BSI was 40.4% at 100 days after the second HSCT, with Gram-positive bacteria accounting for the majority (30.8%) of pathogens. Overall, 92.0% of BSIs occurred during the pre-engraftment period, and Enterococcus faecium accounted for 29.6% of pathogens. On a multivariate analysis, CBT was most closely associated with pre-engraftment BSI after the second HSCT (hazard ratio: 3.43, 95% confidence interval: 1.05-11.23, p=0.042). The 1-year survival rate after the second HSCT was lower in patients with BSI than in patients without BSI (p=0.10). Conclusion BSI is common after a second HSCT, especially with CBT. During the pre-engraftment period, BSI caused by pathogens such as E. faecium should be anticipated and appropriately treated to improve transplant outcomes.

Global impact of antibacterial resistance in patients with hematologic malignancies and hematopoietic cell transplant recipients

Patients with hematologic malignancies and hematopoietic cell transplant (HCT) recipients are at high risk of developing bacterial infections. These patients may suffer severe consequences from these infections if they do not receive immediate effective therapies, and thus are uniquely threatened by antimicrobial-resistant bacteria. Here, we outline how the emergence of specific resistant bacteria threatens the effectiveness of established approaches to prevent and treat infections in this population. The emergence of fluoroquinolone resistance among Enterobacterales and viridans group streptococci may decrease the effectiveness of fluoroquinolone prophylaxis during neutropenia. The emergence of Enterobacterales that produce extended-spectrum β-lactamases or carbapenemases and of increasingly resistant Pseudomonas aeruginosa may result in neutropenic patients experiencing delayed time to active antibacterial therapy, and consequently worse clinical outcomes. The ability to select targeted antibacterial therapies after the availability of susceptibility data may be limited in patients infected with metallo-β-lactamase-producing Enterobacterales and difficult-to-treat P. aeruginosa. Vancomycin-resistant enterococci and Stenotrophomonas maltophilia can cause breakthrough infections in patients already being treated with broad-spectrum β-lactam antibiotics. Resistance can also limit the ability to provide oral stepdown antibacterial therapy for patients who could otherwise be discharged from hospitalization. We also outline strategies that have the potential to mitigate the negative impact of antimicrobial resistance, including interventions based on active screening for colonization with resistant bacteria and the use of novel rapid diagnostic assays. Additional research is needed to better understand how these strategies can be leveraged to combat the emerging crisis of antimicrobial resistance in patients with hematologic malignancies and HCT recipients.

Microbiology and Clinical Outcome of Bloodstream Infections in Patients After Hematopoietic Stem Cell Transplantation

Purpose

Patients after hematopoietic stem cell transplantation (HSCT) are often followed by bloodstream infections (BSIs). BSI is an important cause of non-relapse mortality (NRM) in HSCT patients.

Methods

We conducted a retrospective cohort study of patients (aged >14 years) who underwent HSCT at our hospital from 2017 to 2021. Population characteristics, BSI microbiology, resistance to common antibiotics, and 30-day all-cause mortality were analyzed.

Results

Of 3054 patients, 169 (5.5%) had BSIs after HSCT. Male, not in complete remission at transplantation and longer duration of neutropenia were risk factors for the development of BSI after HSCT. These BSIs were Gram-negative bacterial (n=123, 69.49%), Gram-positive bacterial (n=27, 15.25%), fungal (n=11, 6.36%), and polymicrobial (n=16, 9.25%). Among the Gram-negative bacteria, the proportions of isolates resistant to ceftazidime, cefepime, and piperacillin-tazobactam were similar (72.93%, 74.80%, and 77.42%, respectively). The overall drug resistance rates of amikacin and imipenem were 16.13% and 43.90%, respectively. Staphylococcus isolates were methicillin-resistant. In Enterococcus isolates, the penicillin resistance rate was 84.62%. Eleven isolates of Candida tropicalis were resistant to fluconazole and were sensitive to amphotericin B and flucytosine. The 30-day all-cause mortality rate of the 169 patients with BSIs was 8.88%. The 30-day all-cause mortality of patients with Gram-negative bacterial BSIs was 7.32%, 25.00% for polymicrobial BSIs, and 36.36% for fungal BSIs. The 30-day all-cause mortality of patients with fungal BSIs was significantly higher than that of patients with Gram-negative (P=0.0023) and Gram-positive bacteria (P=0.0023). Fungal BSI and non-Hodgkin's lymphoma (NHL) were associated with higher 30-day mortality.

Conclusion

Our study reveals the microbiological characteristics and 30-day all-cause mortality in patients with bloodstream infections after HSCT. Our data provides strong support for empirical antimicrobial therapy and infection prevention strategies for patients with BSIs after HSCT.

Antimicrobial Stewardship on Patients with Neutropenia: A Narrative Review Commissioned by Microorganisms

The emergence of antibiotic resistance poses a global health threat. High-risk patients such as those with neutropenia are particularly vulnerable to opportunistic infections, sepsis, and multidrug-resistant infections, and clinical outcomes remain the primary concern. Antimicrobial stewardship (AMS) programs should mainly focus on optimizing antibiotic use, decreasing adverse effects, and improving patient outcomes. There is a limited number of published studies assessing the impact of AMS programs on patients with neutropenia, where early appropriate antibiotic choice can be the difference between life and death. This narrative review updates the current advances in strategies of AMS for bacterial infections among high-risk patients with neutropenia. Diagnosis, drug, dose, duration, and de-escalation (5D) are the core variables among AMS strategies. Altered volumes of distribution can make standard dose regimens inadequate, and developing skills towards a personalized approach represents a major advance in therapy. Intensivists should partner antibiotic stewardship programs to improve patient care. Assembling multidisciplinary teams with trained and dedicated professionals for AMS is a priority.

Mortality in pediatric oncology and stem cell transplant patients with bloodstream infections

Background

Bloodstream infections (BSI) continue to represent a significant source of morbidity for pediatric oncology patients, however less is known regarding this population's risk of death. We sought to evaluate the risk of BSI and death at a large pediatric cancer center.

Methods

We retrospectively collected inpatient data from pediatric oncology and hematopoietic stem cell transplant (HSCT) patients over a 9-year period. We performed univariate and multivariable modeling to assess risk of BSI and mortality examining the following variables: demographics, underlying malignancy, history of HSCT, central line type, and febrile neutropenia (FN).

Results

During the study period, 6763 admissions from 952 patients met inclusion criteria. BSI occurred in 367 admissions (5.4%) from 231 unique individuals. Risk factors for BSI include younger age, diagnoses of hemophagocytic lymphohistiocytosis or acute myeloid leukemia, ethnicity, and history of HSCT. Mortality for those with BSI was 6.5%, compared to 0.7% without (OR 7.2, CI 4.1 - 12.7, p<0.0001). In patients with BSI, admissions with FN were associated with reduced mortality compared to admissions without FN (OR 0.21, CI 0.05 - 0.94, p=0.04). In both univariate and multivariable analysis, no other risk factor was significantly associated with mortality in patients with BSI.

Conclusion

BSI is a significant source of mortality in pediatric oncology and HSCT patients. While demographic variables contribute to the risk of BSI, they did not influence mortality. These findings highlight the importance of BSI prevention to reduce the risk of death in pediatric oncology patients. Future studies should focus on comprehensive BSI prevention.

Risk factors and outcomes associated with persistent vancomycin resistant Enterococcal Bacteremia

Background

Prior studies have identified that vancomycin resistant enterococcus (VRE) bacteremia that persists for four days or more is an independent predictor of mortality. Despite this, there is no published data to identify those patients at highest risk of developing persistent VRE bacteremia.

Methods

This was a single center, retrospective, case-control study of adult patients with a VRE bloodstream infection (BSI). Case patients were those with persistent bacteremia (≥ 4 days despite VRE-directed therapy) and control patients were those with non-persistent bacteremia. Logistic regression was used to assess risk factors associated with persistent VRE BSIs. Secondary outcomes included in-hospital mortality, recurrent bacteremia, and breakthrough bacteremia.

Results

During the study period, 24/108 (22%) patients had persistently positive blood cultures. Risk factors for persistent bacteremia included severe neutropenia (OR 2.13), 4 out of 4 positive index blood cultures (OR 11.29) and lack of source control (OR 11.88). In an unadjusted analysis, no statistically significant differences in in-hospital mortality (58% versus 40%; p = 0.121), recurrent bacteremia (17% versus 6%; p = 0.090), or breakthrough bacteremia (13% versus 7%; p = 0.402) were observed between groups.

Conclusion

Patients with severe neutropenia, 4 out of 4 positive index blood culture bottles, and lack of source control were more likely to develop persistent VRE bacteremia despite directed antibiotic treatment.

Infectious complications after second allogeneic hematopoietic cell transplant in adult patients with hematological malignancies

We conducted a retrospective review of the infectious complications and outcomes over a 2-year follow-up period of adult patients who received a second allogeneic hematopoietic cell transplant (2nd allo-HCT) during a five-year period at two cancer centers in Michigan. Sixty patients, of whom 44 (73%) had acute leukemia or myelodysplastic syndrome, were studied. The majority (n = 37,62%) received a 2nd allo-HCT because of relapsed leukemia. Infection episodes after the 2nd allo-HCT totaled 112. Bacteria were identified in 76 episodes, the majority of which occurred pre-engraftment. The most common infecting organisms were Enterococcus species and Clostridioides difficile. Viral infections, predominantly cytomegalovirus, accounted for 59 infection episodes and occurred mostly in pre-engraftment and early post-engraftment periods. There were 16 proven/probable fungal infections, of which 9 were invasive aspergillosis or candidiasis. Mortality was 45% (n = 27) at one year and 65% (n = 39) at 2 years after transplant, and 16 deaths (41%) were due to infection. Of those 16 infection deaths, 8 were bacterial, 4 fungal, 2 both bacterial and fungal, and 2 viral. Failure to engraft neutrophils or platelets was significantly associated with decreased survival, p < 0.0001 and p < 0.001, respectively. Infections are common after a 2nd allo-HCT and are associated with a high mortality rate.

Epidemiological and genetic characteristics of vancomycin-resistant Enterococcus faecium isolates in a University Children's Hospital in Germany: 2019 to 2020

Background

Vancomycin-resistant Enterococcus faecium (VREfm) strains are one of the most important pathogens causing nosocomial infections in Germany. Due to limited treatment options and an increased risk for acquisition in immunocompromised children, surveillance to monitor occurrence of VREfm in paediatric clinical facilities is of critical importance. Following an unusual accumulation of VREfm positive patients between April 2019 and August 2020 at Dr. von Hauner Children’s Hospital in Munich, Germany, our study aimed to identify dynamics and routes of transmission, and analyse the affected population in view of previously described host risk factors for VREfm colonisation or infection.

Methods

The hospital database was used to collect epidemiological and clinical data of VREfm cases. Descriptive statistical analyses were conducted to outline patient characteristics and depict possible differences between VREfm-colonised and -infected children. An outbreak investigation determining genetic relatedness among VREfm isolates was performed by core genome multilocus sequence typing (cgMLST). To examine potential transmission pathways, results of genome analysis were compared with epidemiological and clinical data of VREfm positive patients.

Results

VREfm acquisition was documented in a total of 33 children (< 18 years). Seven VREfm-colonised patients (21.2%), especially those with a haemato-oncological disease (4/7; p = 0.011), showed signs of clinical infection. cgMLST analysis revealed seven distinct clusters, demonstrating a possible connection within each clonal lineage. Additional eight singletons were identified. Comparison with epidemiological and clinical data provided strong evidence for a link between several VREfm positive patients within the hospital.

Conclusions

A nosocomial spread—at least in part—was the most likely reason for the unusual accumulation of VREfm cases. The study highlights that there is a constant need to increase efforts in hygiene measures, infection control and antibiotic stewardship to combat VREfm transmission events within German paediatric hospitals. Continuous monitoring of adherence to respective policies might reduce the occurrence of clustered cases and prevent future outbreaks.

Infections in Hospitalized Cancer Patients

Cancer patients are at an increased risk of developing infections that are primarily treatment-driven but may also be malignancy-driven. While cancer treatments such as chemotherapy, radiotherapy, and surgery have been known to improve malignancy morbidity and mortality, they also have the potential to weaken immune defenses and induce periods of severe cytopenia. These adverse effects pave the way for opportunistic infections to complicate a hospitalized cancer patient's clinical course. Understanding the risk each patient inherently has for developing a bacterial, fungal, or viral infection is critical to choosing the correct prophylactic treatment in conjunction with their scheduled cancer therapy. This review discusses the most common types of infections found in hospitalized cancer patients as well as the current guidelines for prophylactic and antimicrobial treatment in cancer patients. In addition, it describes the interaction between antibiotics and cancer therapies for consideration when treating infection in a cancer patient.

Severe acute graft-versus-host disease increases the incidence of blood stream infection and mortality after allogeneic hematopoietic cell transplantation: Japanese transplant registry study

This study aimed to clarify the risk factors and prognosis associated with blood stream infection (BSI) in allogeneic hematopoietic cell transplantation (allo-HCT), and the relationship between BSI and acute graft-versus-host disease (aGVHD). This retrospective analysis included 11,098 patients in the Japanese national transplant registry. A total of 2172 patients developed BSI after allo-HCT, with 2332 identified pathogens. The cumulative incidences of BSI were 15.5% at 30 days and 20.9% at 100 days after allo-HCT. In a multivariate analysis, severe (grade III-IV) aGVHD was associated with a higher risk of BSI (vs. grade 0-I aGVHD: hazard ratio [HR] 3.34 [95% confidence interval (CI), 2.85-3.92; P < 0.001]). In a multivariate analysis, severe aGVHD before BSI was associated with a higher risk of overall mortality after BSI (vs. grade 0-I aGVHD: HR 2.61 [95% CI 2.18-3.11; P < 0.001]). In addition, BSI (vs. no-BSI: HR 1.20 [95% CI, 1.12-1.29; P < 0.001]) and severe aGVHD (vs. grade 0-I aGVHD: HR 1.97 [95% CI, 1.83-2.12; P < 0.001]) were independent risk factors for overall mortality after allo-HCT. In the setting of allo-HCT, severe aGVHD was associated with increases in both BSI incidence and post-BSI overall mortality. Furthermore, BSI was an independent risk factor for overall mortality.

Secular trends of Blood stream infections in allogeneic hematopoietic cell transplant recipients 72 hours prior to death

INTRODUCTION

Blood stream infections (BSI) frequently cause morbidity and mortality in allogeneic (allo) hematopoietic cell transplant (HCT) recipients. Characteristics of causative organisms shortly before death have not been previously described. Early treatment with antimicrobial agents targeting the recent surge in multidrug-resistant (MDR) pathogens may lead to better outcomes.

METHODS

This is retrospective study including 529 allo HCT recipients who died between 2000 and 2013. All patients who had BSI that happened 72 hours before death were included. BSI and criteria for antimicrobial resistance were defined according to the Centers for Disease Control and Prevention and the National Healthcare Safety Network surveillance criteria.

RESULTS

Overall, 104 BSI were identified from 91 patients. Bacterial infections accounted for 87% of the infections which were comprised by 37% gram-negative organisms and 50% gram-positive bacteria. The most common species were Enterococcus (30%), Staphylococcus (16%), and Pseudomonas (16%). Most enterococci were vancomycin resistant (87%), 100% of staphylococci were resistant to methicillin, and 64% of Pseudomonas were MDR. Over time there was a significant increase in vancomycin-resistant enterococcal (P = .01) and gram-negative BSI (P = .01). Blood stream infections were either the primary or secondary cause of death in 53% of patients.

CONCLUSIONS

In allo HCT recipients, vancomycin-resistant enterococcal infections caused the majority of BSI 72 hours prior to death. Our findings provide information that may guide empiric antibiotic coverage in critically ill HCT recipients.

Profiling of bacterial bloodstream infections in hematological and oncological patients based on a comparative survival analysis

Bloodstream infections (BSI) are a frequent complication in patients with hematological and oncological diseases. However, the impact of different bacterial species causing BSI and of multiple BSI remains incompletely understood. We performed a retrospective study profiling 637 bacterial BSI episodes in hematological and oncological patients. Based on the 30-day (30d) overall survival (OS), we analyzed different types of multiple BSI and grouped BSI-associated bacteria into clusters followed by further assessment of clinical and infection-related characteristics. We discovered that polymicrobial BSI (different organisms on the first day of a BSI episode) and sequential BSI (another BSI before the respective BSI episode) were associated with a worse 30d OS. Different bacterial groups could be classified into three BSI outcome clusters based on 30d OS: favorable (FAV) including mainly common skin contaminants, Escherichia spp. and Streptococcus spp.; intermediate (INT) including mainly Enterococcus spp., vancomycin-resistant Enterococcus spp., and multidrug-resistant gram-negative bacteria (MDRGN); and adverse (ADV) including MDRGN with an additional carbapenem-resistance (MDRGN+CR). A polymicrobial or sequential BSI especially influenced the outcome in the combination of two INT cluster BSI. The presence of a polymicrobial BSI and the assignment into the BSI outcome clusters were identified as independent risk factors for 30d mortality in a Cox multivariate regression analysis. The assignment to a BSI outcome cluster and the differentiated perspective of multiple BSI open new insights into the prognosis of patients with BSI and should be further validated in other patient cohorts.

Antimicrobial Stewardship in a Hematological Malignancy Unit: Carbapenem Reduction and Decreased Vancomycin-Resistant Enterococcus Infection

BACKGROUND

Antibiotic stewardship is challenging in hematological malignancy patients.

METHODS

We performed a quasiexperimental implementation study of 2 antimicrobial stewardship interventions in a hematological malignancy unit: monthly antibiotic cycling for febrile neutropenia that included cefepime (± metronidazole) and piperacillin-tazobactam and a clinical prediction rule to guide anti-vancomycin-resistant Enterococcus faecium (VRE) therapy. We used interrupted time-series analysis to compare antibiotic use and logistic regression in order to adjust observed unit-level changes in resistant infections by background community rates.

RESULTS

A total of 2434 admissions spanning 3 years pre- and 2 years postimplementation were included. Unadjusted carbapenem and daptomycin use decreased significantly. In interrupted time-series analysis, carbapenem use decreased by -230 days of therapy (DOT)/1000 patient-days (95% confidence interval [CI], -290 to -180; P < .001). Both VRE colonization (odds ratio [OR], 0.64; 95% CI, 0.51 to 0.81; P < .001) and infection (OR, 0.41; 95% CI, 0.2 to 0.9; P = .02) decreased after implementation. This shift may have had a greater effect on daptomycin prescribing (-160 DOT/1000 patient-days; 95% CI, -200 to -120; P < .001) than did the VRE clinical prediction score (-30 DOT/1000 patient-days; 95% CI, -50 to 0; P = .08). Also, 46.2% of Pseudomonas aeruginosa isolates were carbapenem-resistant preimplementation compared with 25.0% postimplementation (P = .32). Unit-level changes in methicillin-resistant Staphylococcus aureus and extended-spectrum beta lactamase (ESBL) incidence were explained by background community-level trends, while changes in AmpC ESBL and VRE appeared to be independent. The program was not associated with increased mortality.

CONCLUSIONS

An antibiotic cycling-based strategy for febrile neutropenia effectively reduced carbapenem use, which may have resulted in decreased VRE colonization and infection and perhaps, in turn, decreased daptomycin prescribing.

Clinical characteristics and drug susceptibility patterns of Corynebacterium species in bacteremic patients with hematological disorders

The aim of this study was to clarify the clinical and microbiological characteristics of Corynebacterium bacteremia in hematological patients. We retrospectively reviewed the medical records of patients with Corynebacterium bacteremia from April 2013 to June 2018. The causative Corynebacterium species were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Drug susceptibility tests were performed using the broth microdilution method recommended by the Clinical and Laboratory Standards Institute. In total, 147 cases of Corynebacterium bacteremia were identified during the study period. Corynebacterium striatum was the most frequent pathogen. Catheter-related bloodstream infection was diagnosed in 19.7% of all patients, and moderate/severe oral or severe gastrointestinal mucosal impairment was detected in 19.7%. Polymicrobial infection was found in about 20% of cases, with Enterococcus faecium being the most frequent isolate. The overall 30-day mortality was 34.7% (51/147). Multivariate analysis showed that E. faecium co-infection (odds ratio (OR) 9.3; 95% confidence interval (CI) 2.1-40), systemic corticosteroids (OR 3.6; 95% CI 1.4-8.9), other immunosuppressive drugs (OR 0.32; 95% CI 0.13-0.76), and a Pitt bacteremia score ≥4 (OR 12; 95% CI 3.9-40) were significant risk factors for overall 30-day mortality. The drug susceptibility rates for beta-lactam antimicrobial agents were quite low. All isolates were susceptible to glycopeptides and linezolid. However, some C. striatum isolates were resistant to daptomycin. Corynebacterium bacteremia can occur in the presence of several types of mucosal impairment. Our drug susceptibility data indicate that Corynebacterium bacteremia in hematological patients could be treated by glycopeptides or linezolid.

Epidemiology and Outcomes of Vancomycin-Resistant Enterococcus Infections in the U.S. Military Health System

INTRODUCTION

Vancomycin-resistant enterococci (VRE) are classified by the Centers for Diseases Control and Prevention as a serious antibiotic resistance threat. Our study aims to characterize the epidemiology, associated conditions, and outcomes of VRE infections among hospitalized patients in the U.S. military health system (MHS).

MATERIALS AND METHODS

We performed a retrospective cohort study of patients with VRE infection using the MHS database. Cases included all patients admitted to a military treatment facility for ≥2 days from October 2008 to September 2015 with a clinical culture growing Enterococcus faecalis, Enterococcus faecium, or Enterococcus species (unspecified), reported as resistant to vancomycin. Co-morbid conditions and procedures associated with VRE infection were identified by multivariable conditional logistic regression. Patient case-mix adjusted outcomes including in-hospital mortality, length of stay, and hospitalization cost were evaluated by high-dimensional propensity score adjustment.

RESULTS

During the seven-year study period and among 1,161,335 hospitalized patients within the MHS, we identified 577 (0.05%) patients with VRE infection. A majority of VRE infections were urinary tract infections (57.7%), followed by bloodstream (24.7%), other site/device-related (12.9%), respiratory (2.9%), and wound infections (1.8%). Risk factors for VRE infection included invasive gastrointestinal, pulmonary, and urologic procedures, indwelling devices, and exposure to 4th generation cephalosporins, but not to glycopeptides. Patients hospitalized with VRE infection had significantly higher hospitalization costs (attributable difference [AD] $135,534, P<0.001), prolonged hospital stays (AD 20.44 days, P<0.001, and higher in-hospital mortality (case-mix adjusted odds ratio 5.77; 95% confidence interval 4.59-7.25).

CONCLUSIONS

VRE infections carry a considerable burden for hospitalized patients given their impact on length of stay, hospitalization costs, and in-hospital mortality. Active surveillance and infection control efforts should target those identified as high-risk for VRE infection. Antimicrobial stewardship programs should focus on limiting exposure to 4th generation cephalosporins.

Enterococcal bacteraemia 'silent but deadly': a population-based cohort study

BACKGROUND

The high mortality rate of patients with enterococcal infections has been shown to be associated with the severity of underlying comorbidities.

AIMS

To characterise the epidemiology, clinical characteristics, outcomes and predictors of mortality in patients with enterococcal bacteraemia.

METHODS

This was a retrospective cohort study of all enterococcal bacteraemia episodes in the Barwon region between January 2010 and March 2017. We assessed the epidemiology, clinical characteristics, outcomes and predictors of mortality using descriptive statistics and simple and multiple logistic regression analyses.

RESULTS

The incidence of enterococcal bacteraemia was 19.9/100 000 person-years. Males comprised 68.4%, and the median age was 71 years. Common comorbidities were gastrointestinal tract disease, urological disease, malignancies and cardiovascular disease. Infective endocarditis was observed in 15% of patients, and 1 of 27 also had colorectal cancer. Twelve patients referred for colonoscopy demonstrated previously undiagnosed colorectal neoplasia in 75% of these cases. The 30-day and 1-year mortality rates were 11.7 and 40.2% respectively. Sixty-nine cases with vancomycin-resistant Enterococcus were observed. Multiple logistic regression suggested that the presence of underlying urological malignancy (adjusted odds ratio = 3.57, 95% confidence intervals = 1.10-11.65, P = 0.035) and colorectal cancer (adjusted odds ratio = 4.47, 95% confidence intervals = 1.36-14.66, P = 0.014) were significant predictors of 1-year mortality.

CONCLUSIONS

Microbiological cure was inversely associated with 30-day mortality. The presence of underlying urological and colorectal malignancy was a predictor of 1-year mortality. We identified the importance of evaluating patients with Enterococcus faecalis bacteraemia for underlying colorectal neoplasia. Routine colonoscopy is recommended in patients with E. faecalis bacteraemia or infective endocarditis with an unclear source of infection.

Immunopathology and biology-based treatment of steroid-refractory graft-versus-host disease

Acute graft-versus-host disease (GVHD) is 1 of the major life-threating complications after allogeneic cell transplantation. Although steroids remain first-line treatment, roughly one-half of patients will develop steroid-refractory GVHD (SR-GVHD), which portends an extremely poor prognosis. Many agents that have shown encouraging response rates in early phase 1/2 trials for prevention and treatment have been unsuccessful in demonstrating a survival advantage when applied in the setting of SR-GVHD. The discovery of novel treatments has been further complicated by the absence of clinically informative animal models that address what may reflect a distinct pathophysiology. Nonetheless, the combined knowledge of established bone marrow transplantation models and recent human trials in SR-GVHD patients are beginning to illuminate novel mechanisms for inhibiting T-cell signaling and promoting tissue tolerance that provide an increased understanding of the underlying biology of SR-GVHD. Here, we discuss recent findings of newly appreciated cellular and molecular mechanisms and provide novel translational opportunities for advancing the effectiveness of treatment in SR-GVHD.

Bloodstream Infection Due to Vancomycin-resistant Enterococcus Is Associated With Increased Mortality After Hematopoietic Cell Transplantation for Acute Leukemia and Myelodysplastic Syndrome: A Multicenter, Retrospective Cohort Study

BACKGROUND

We examined the impact of vancomycin-resistant Enterococcus (VRE) bloodstream infection (BSI) on outcomes of allogeneic hematopoietic cell transplantation (HCT) utilizing the Center for International Blood and Marrow Transplant Research database.

METHODS

Adult and pediatric patients (N = 7128) who underwent first HCT for acute leukemia or myelodysplastic syndrome from 2008 through 2012 were analyzed as 3 groups-VRE BSI, non-VRE BSI, without BSI-according to BSI status at 100 days (D100) after allogeneic HCT. Multivariable models examined the effect of VRE BSI for overall survival (OS) and nonrelapse mortality (NRM) at 1 year.

RESULTS

Of 7128 patients, 258 (3.2%) had VRE BSI, 2398 (33.6%) had non-VRE BSI, and 4472 (63%) had no BSI. The median time to VRE BSI and non-VRE BSI were D11 and D15, respectively. Compared with non-VRE BSI patients, VRE BSI patients were older, had advanced-stage acute leukemia, and received umbilical cord blood (UCB) allografts. In multivariable models, VRE BSI was associated with lower OS (relative risk [RR], 2.9;(99% confidence interval [CI], 2.2-3.7) and increased NRM (RR, 4.7; 99% CI, 3.6-6.2) (P < .0001) for both. Other predictors for worse OS and increased NRM were non-VRE BSI, older age, advanced disease stage, UCB allograft, - mismatch, comorbidity index ≥3, and cytomegalovirus seropositivity (P < .001 for all variables).

CONCLUSIONS

VRE BSI is associated with lowest OS and highest NRM compared with patients without BSI or non-VRE BSI. Novel interventions that address the pathophysiology of VRE BSI have the potential of improving survival after HCT.

Effectiveness of Bath Wipes After Hematopoietic Cell Transplantation: A Randomized Trial

Objective: Bacteremia is a leading cause of morbidity and mortality in children undergoing hematopoietic cell transplantation (HCT). Infections of vancomycin-resistant enterococci (VRE) and multidrug resistant (MDR) gram-negative rods (GNRs) are common in this population. Our objective was to assess whether experimental bath wipes containing silver were more effective than standard bath wipes containing soap at reducing skin colonization by VRE and MDR GNRs, and nonmucosal barrier injury bacteremia. Study Design: Patients undergoing autologous or allogeneic HCT in a tertiary referral center were randomized to receive experimental or standard bath wipes for 60 days post-HCT. Skin swabs were collected at baseline, discharge, and day +60 post-HCT. The rate of VRE colonization was chosen as the marker for efficacy. Results: Experimental bath wipes were well tolerated. Before the study, the rate of colonization with VRE in HCT recipients was 25%. In an interim analysis of 127 children, one (2%) patient in the experimental arm and two (3%) in the standard arm were colonized with VRE. Two (3%) patients had nonmucosal barrier injury bacteremia in the standard arm, with none in the experimental arm. MDR GNRs were not isolated. The trial was halted because the interim analyses indicated equivalent efficacy of the two methods. Conclusions: Skin cleansing with silver-containing or standard bath wipes resulted in very low and equivalent rates of bacteremia and colonization with VRE and MDR GNRs in children post-HCT. Future studies in other high-risk populations are needed to confirm these results.

Enterococcal Bacteremia in Children With Malignancies and Following Hematopoietic Stem Cell Transplantation: A 15-Year Single-Center Experience

BACKGROUND

Data on enterococcal bacteremia (EB) in immunocompromised children are scarce. We aimed to describe EB in children with hematologic malignancies (HM), solid tumors and/or following allogeneic hematopoietic stem cell transplantation (HSCT) and analyze their ampicillin and vancomycin resistance.

METHODS

We conducted an observational retrospective study in the tertiary-care Hadassah University Medical Center (2001-2015). We collected demographic, clinical and laboratory data on EB and compared ampicillin and vancomycin sensitive with resistant episodes.

RESULTS

Fifty-six of 1123 children developed 74 episodes of EB; 62.1% Enterococcus faecium, 36.5% Enterococcus faecalis; and 1.4% Enterococcus gallinarum. EB developed in 12.1% of HSCT patients, 5.1% of HM, 6.3% of neuroblastoma and 1.0% of other solid tumors patients. Of these episodes, 85.1% were nosocomial, and 71.6% developed while on antibiotic therapy. Resistance rates were: to ampicillin, 57.6%; to vancomycin (vancomycin-resistant enterococci), 21.6%; and higher rates among E. faecium. Among vancomycin-resistant enterococci, 1 of 16 was linezolid and 2 of 10 daptomycin resistant. Overall 7- and 30-day mortality rates were 2.7% and 5.4%, respectively. Thirty-day mortality was 18.2% in recurrent episodes and 0% in the first-time EB episodes (P = 0.006). In multivariate analysis, high treatment intensity was associated with ampicillin resistance [odds ratio (OR) = 3.18, 95% confidence interval (CI): 1.31-9.12], prior penicillin exposure (OR = 7.50, 95% CI: 1.41-39.81) and breakthrough on vancomycin (OR = 18.83, 95% CI: 3.31-101.14) with vancomycin resistance.

CONCLUSIONS

EB occurs mainly as a nosocomial infection in children receiving high-intensity chemotherapy, especially in those with neuroblastoma, HM and following HSCT. Antibiotic resistance is common. Vancomycin resistance can occur regardless of previous vancomycin use. Prognosis in immunocompromised children with EB is better than previously reported. Recurrent EB is associated with increased mortality.

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.

Does vancomycin resistance increase mortality in Enterococcus faecium bacteraemia after orthotopic liver transplantation? A retrospective study

BACKGROUND

The relevance of vancomycin resistance in enterococcal blood stream infections (BSI) is still controversial. Aim of this study was to outline the effect of vancomycin resistance of Enterococcus faecium on the outcome of patients with BSI after orthotopic liver transplantation (OLT).

METHODS

The outcome of OLT recipients developing BSI with vancomycin-resistant (VRE) versus vancomycin-susceptible Enterococcus faecium (VSE) was compared based on data extraction from medical records. Multivariate regression analyses identified risk factors for mortality and unfavourable outcomes (defined as death or prolonged intensive care stay) after 30 and 90 days.

RESULTS

Mortality was similar between VRE- (n = 39) and VSE- (n = 138) group after 30 (p = 0.44) or 90 days (p = 0.39). Comparable results occurred regarding unfavourable outcomes. Mean SOFA_Non-GCS score during the 7-day-period before BSI onset was the independent predictor for mortality at both timepoints (HR 1.32; CI 1.14-1.53; and HR 1.18; CI 1.08-1.28). Timely appropriate antibiotic therapy, recent ICU stay and vancomycin resistance did not affect outcome after adjusting for confounders.

CONCLUSION

Vancomycin resistance did not influence outcome among patients with Enterococcus faecium bacteraemia after OLT. Only underlying severity of disease predicted poor outcome among this homogenous patient population.

TRIAL REGISTRATION

This study was registered at the German clinical trials register (DRKS-ID: DRKS00013285).

Febrile Neutropenia in Acute Leukemia. Epidemiology, Etiology, Pathophysiology and Treatment

Acute leukemias are a group of aggressive malignant diseases associated with a high degree of morbidity and mortality. An important cause of both the latter is infectious complications. Patients with acute leukemia are highly susceptible to infectious diseases due to factors related to the disease itself, factors attributed to treatment, and specific individual risk factors in each patient. Patients with chemotherapy-induced neutropenia are at particularly high risk, and microbiological agents include viral, bacterial, and fungal agents. The etiology is often unknown in infectious complications, although adequate patient evaluation and sampling have diagnostic, prognostic and treatment-related consequences. Bacterial infections include a wide range of potential microbes, both Gram-negative and Gram-positive species, while fungal infections include both mold and yeast. A recurring problem is increasing resistance to antimicrobial agents, and in particular, this applies to extended-spectrum beta-lactamase resistance (ESBL), Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and even carbapenemase-producing Enterobacteriaceae (CPE). International guidelines for the treatment of sepsis in leukemia patients include the use of broad-spectrum Pseudomonas-acting antibiotics. However, one should implant the knowledge of local microbiological epidemiology and resistance conditions in treatment decisions. In this review, we discuss infectious diseases in acute leukemia with a major focus on febrile neutropenia and sepsis, and we problematize the diagnostic, prognostic, and therapeutic aspects of infectious complications in this patient group. Meticulously and thorough clinical and radiological examination combined with adequate microbiology samples are cornerstones of the examination. Diagnostic and prognostic evaluation includes patient review according to the multinational association for supportive care in cancer (MASCC) and sequential organ failure assessment (SOFA) scoring system. Antimicrobial treatments for important etiological agents are presented. The main challenge for reducing the spread of resistant microbes is to avoid unnecessary antibiotic treatment, but without giving to narrow treatment to the febrile neutropenic patient that reduce the prognosis.

Lactose drives Enterococcus expansion to promote graft-versus-host disease

Disruption of intestinal microbial communities appears to underlie many human illnesses, but the mechanisms that promote this dysbiosis and its adverse consequences are poorly understood. In patients who received allogeneic hematopoietic cell transplantation (allo-HCT), we describe a high incidence of enterococcal expansion, which was associated with graft-versus-host disease (GVHD) and mortality. We found that Enterococcus also expands in the mouse gastrointestinal tract after allo-HCT and exacerbates disease severity in gnotobiotic models. Enterococcus growth is dependent on the disaccharide lactose, and dietary lactose depletion attenuates Enterococcus outgrowth and reduces the severity of GVHD in mice. Allo-HCT patients carrying lactose-nonabsorber genotypes showed compromised clearance of postantibiotic Enterococcus domination. We report lactose as a common nutrient that drives expansion of a commensal bacterium that exacerbates an intestinal and systemic inflammatory disease.

Contribution of specific pathogens to bloodstream infection mortality in neutropenic patients with hematologic malignancies: Results from a multicentric surveillance cohort study

Bloodstream infection (BSI) remains a serious complication in patients with hematologic malignancies and neutropenia. The risk factors for mortality after BSI and the contributions of BSI pathogens to mortality remain incompletely understood. We evaluated first BSI among adult neutropenic patients undergoing high-dose chemotherapy for hematologic malignancies in the setting of (a) an early disease stage of autologous (auto-HSCT) or allogeneic (allo-HSCT) hematopoietic stem cell transplantation or (b) for acute leukemia. Risk factors for intensive care admission and all-cause mortality were analyzed by multivariable logistic regression 7 and 30 days after onset of the first BSI in the first neutropenic episode. Between 2002 and 2015, 9080 patients met the study inclusion criteria, and 1424 (16%) developed BSIs, most of them during the first week of neutropenia. Mortality during neutropenia within 7 days and 30 days after BSI onset was 2.5% and 5.1%, respectively, and differed considerably between BSI pathogens. Both 7-day and 30-day mortalities were highest for Pseudomonas aeruginosa BSI (16.7% and 26.7%, respectively) and lowest for BSI due to coagulase-negative Staphylococcus spp. (CoNS) and Streptococcus spp. BSI pathogens were independently associated with 7-day mortality included P aeruginosa, Klebsiella spp., Enterobacter spp., Serratia spp., and enterococci. Only gram-negative BSI and candidemia were associated with admission to intensive care within 7 days after BSI onset. BSI caused by P aeruginosa continues to carry a particularly poor prognosis in neutropenic patients. The unexpected association between enterococcal BSI and increased mortality needs further study.

Adjunctive gentamicin did not improve outcome of enterococcal bacteraemia in neutropenic patients: a propensity scored matched study

BACKGROUND

Patients with haematologic malignancies receiving chemotherapy have a high risk of developing febrile neutropenia and bloodstream infections. The benefit of adjunctive gentamicin treatment for enterococcal bloodstream infections is debated. In this study, we compare the treatment outcome of a cell wall-active antibiotic with and without gentamicin for enterococcal bacteraemia in patients with neutropenia.

METHODS

The observational study was performed from 1999 through 2016. Patients with bacteraemia due to non-high level gentamicin-resistant enterococci were included. Analyses were performed in two data sets of episodes with enterococcal bacteraemia. One data set consisting of all included episodes (full cohort, n = 154) and one with propensity score-matched episodes (n = 96). The primary endpoint was death within 30 days, and the secondary outcomes were defervescence and persistence of enterococcal bloodstream infection after initiation of anti-enterococcal therapy.

RESULTS

Episodes with gentamicin treatment (n = 82, full cohort; n = 48, propensity score-matched cohort) were comparable with episodes without gentamicin treatment (n = 72, full cohort; n = 48, propensity score-matched cohort) with regard to patient- and disease-related characteristics. Enterococcus faecium (40.9%) was the most frequently isolated organism. In the propensity score-matched cohort, there was no difference in 30-days mortality (14.6% in episodes with gentamicin versus 16.7% in episodes without gentamicin, p = 1), median time to defervescence (1 versus 2 days, p = .37) or persistence of enterococcal bloodstream infection for ≥72 h (9.4% versus 7.5%, p = 1).

CONCLUSIONS

In our study with neutropenic patients, treatment with a cell wall-active antibiotic without adjunctive gentamicin for episodes with enterococcal bloodstream infection was as effective as combination therapy with gentamicin.

Infectious Complications After Umbilical Cord Blood Transplantation for Hematological Malignancy

Background

Umbilical cord blood transplant (UCBT) is used for patients who do not have a matched donor, but engraftment often takes longer than with a standard allogeneic transplant, likely increasing the risk for infection. We characterized specific infections and outcomes in adults undergoing UCBT at our 2 centers.

Methods

All adults who underwent UCBT between January 1, 2006 and December 31, 2015 were included. Infectious episodes from 6 months before to 2 years after UCBT were reviewed.

Results

Fifty-seven patients underwent UCBT; 47 had neutrophil engraftment. A total of 179 infectious episodes occurred in 55 patients, 73 (41%) within 30 days post-UCBT. Viruses caused 85 (47%) infections. Cytomegalovirus caused 32 infectious episodes and was most common from day 30 to 100. Human herpesvirus 6 occurred in 28 episodes, was most common within 30 days, and caused 1 death. Bacteria were responsible for 82 (46%) infections, most commonly bacteremias due to Staphylococcus spp, Enterococcus spp, and Enterobacteriaceae. Of 11 invasive fungal infections, 9 were aspergillosis, 4 of which were fatal. Overall mortality was 56% in the first year. Thirteen deaths were from infection; 11 occurred in the first 100 days and 7 in the first 30 days post-UCBT. Of 10 patients who never engrafted, 9 died, 6 from infection, within 100 days post-UCBT.

Conclusions

Infectious complications were common after UCBT, especially in the first 30 days. Deaths from viral infections were fewer than expected. Delayed engraftment and nonengraftment continue to convey increased risk for fatal bacterial and fungal infections post-UCBT.

Bacteremias following autologous stem cell transplantation for multiple myeloma: Risk factors and outcomes

BACKGROUND

Autologous stem cell transplantation (ASCT) is a commonly used treatment for multiple myeloma (MM). This retrospective cohort study characterizes the risk factors and outcomes associated with bacteremia following ASCT at a single center.

METHODS

We conducted a retrospective analysis in subjects who underwent ASCT for multiple myeloma and other malignancies from May 2014 to March 2015 at a single center. The control cohort included all subjects undergoing ASCT in the same time period who did not develop bacteremia.

RESULTS

During the study period, 363 ASCTs were completed in 282 discrete patients. Bacteremia was documented in 13% of all transplants. Enterococcus faecium was the most frequent species overall (14/62, 23%). Vancomycin resistance was present in 93% of E faecium isolates. Bacteremia was associated with a significantly decreased survival in patients who received their transplant after the first year of myeloma treatment. Overall survival (OS) was not significantly different in the two cohorts among patients undergoing ASCT within the first year of myeloma treatment. Survival analysis showed a significantly decreased OS in patients who developed Enterococcus bacteremia as compared to the non-bacteremia cohort. Enterococcal bacteremia was associated with significantly longer duration of neutropenia (mean 14 vs 9.7 days, P = 0.01), hospitalization (mean 61.7 vs 20.4 days, P = 0.0006), and higher mortality (69% vs 25%, P = 0.01) as compared to other bacteremias.

CONCLUSION

We found a high incidence of E faecium and a low incidence of MRSA and Pseudomonas bacteremias following ASCT in our patient population. Survival analysis in our cohort suggests that the effect of underlying disease status and cumulative chemotherapy is critically important in determining outcomes related to bacteremia. Enterococcal bacteremias following ASCT were associated with significantly higher morbidity and mortality than non-enterococcal bacteremias.

Bloodstream infections with vancomycin-resistant enterococci are associated with a decreased survival in patients with hematological diseases

Enterococcus species are commensals of the human gastrointestinal tract with the ability to cause invasive infections. For patients with hematological diseases, enterococcal bloodstream infections (BSI) constitute a serious clinical complication which may even be aggravated if the pathogen is vancomycin-resistant. Therefore, we analyzed the course of BSI due to vancomycin-susceptible enterococci (VSE) in comparison to vancomycin-resistant enterococci (VRE) on patient survival. In this retrospective single-center study, BSI were caused by VRE in 47 patients and by VSE in 43 patients. Baseline patient characteristics were similar in both groups. Concerning infection-related characteristics, an increased CRP value and an increased rate of prior colonization with multidrug-resistant organisms were detected in the VRE BSI group. More enterococcal invasive infections were found in the VSE group. The primary endpoint, overall survival (OS) at 30 days after BSI, was significantly lower in patients with VRE BSI compared to patients with VSE BSI (74.5% vs. 90.7%, p = 0.039). In a multivariate regression analysis, VRE BSI and a Charlson comorbidity index higher than 4 were independent factors associated with 30-day mortality. Moreover, we found that VRE with an additional teicoplanin resistance showed a trend towards an even lower OS.

Utilizing genomic analyses to investigate the first outbreak of vanA vancomycin-resistant Enterococcus in Australia with emergence of daptomycin non-susceptibility

INTRODUCTION

The majority of vancomycin-resistant Enterococcus faecium (VREfm) in Australia is of the vanB genotype. An outbreak of vanA VREfm emerged in our haematology/oncology unit between November 2014 and May 2015. The first case of daptomycin non-susceptible E. faecium (DNSEfm) detected was a patient with vanA VREfm bacteraemia who showed clinical failure of daptomycin therapy, prompting microbiologic testing confirming daptomycin non-susceptibility.

OBJECTIVES

To describe the patient profiles, antibiotic susceptibility and genetic relatedness of vanA VREfm isolates in the outbreak.

METHODS

Chart review of vanA VREfm colonized and infected patients was undertaken to describe the demographics, clinical features and outcomes of therapy. Whole genome sequencing of vanA VREfm isolates involved in the outbreak was conducted to assess clonality.

RESULTS

In total, 29 samples from 24 patients tested positive for vanA VREfm (21 screening swabs and 8 clinical isolates). Five isolates were DNSEfm (four patients colonized, one patient with bacteraemia), with only one patient exposed to daptomycin previously. In silico multi-locus sequence typing of the isolates identified 25/26 as ST203, and 1/26 as ST796. Comparative genomic analysis revealed limited core genome diversity amongst the ST203 isolates, consistent with an outbreak of a single clone of vanA VREfm.

CONCLUSIONS

Here we describe an outbreak of vanA VREfm in a haematology/oncology unit. Genomic analysis supports transmission of an ST203 vanA VRE clone within this unit. Daptomycin non-susceptibility in 5/24 patients left linezolid as the only treatment option. Daptomycin susceptibility cannot be assumed in vanA VREfm isolates and confirmatory testing is recommended.

Enterococcal bacteremia in febrile neutropenic children and adolescents with underlying malignancies, and clinical impact of vancomycin resistance

PURPOSE

Enterococci are a common cause of bacteremia in immunocompromised patients. Although the increase of vancomycin-resistant enterococci (VRE) makes appropriate antibiotic therapy difficult, clinical characteristics of enterococcal bacteremia and the impact of VRE infection on outcomes have rarely been reported in immunocompromised children.

METHODS

We enrolled children and adolescents (< 19 years of age) with underlying malignancies who were diagnosed with enterococcal bacteremia during febrile neutropenia between 2010 and 2017. Medical records of the enrolled children were retrospectively reviewed to evaluate the clinical characteristics of enterococcal bacteremia and impact of VRE infection on outcomes.

RESULTS

Thirty-six episodes of enterococcal bacteremia were identified in 30 patients. VRE infection was identified in 11 episodes (30.6%); the 7- and 30-day mortalities were 27.8% and 44.4%, respectively. Acute lymphoblastic leukemia (50.0%) and acute myeloid leukemia (30.6%) were the most common underlying disorders. Three (8.3%) of the patients were in complete remission, and palliative and reinduction chemotherapies were administered in 47.2% and 36.1% of episodes, respectively. Empirical antibiotic therapy was appropriate in 64.0% of patients with vancomycin-susceptible enterococcal infection and in none of the VRE-infected patients (p = 0.001). However, the 30-day mortality was not significantly different between the two patient groups (44.0% vs. 45.5%, p = 1.000).

CONCLUSIONS

Most episodes of enterococcal bacteremia occurred in advanced stages of underlying malignancies, and still showed high mortality. The prognosis seemed to be related to the underlying disease condition rather than vancomycin resistance of the isolated enterococci, although the number of enrolled patients was small.

Impact of Empiric Treatment for Vancomycin-Resistant Enterococcus in Colonized Patients Early after Allogeneic Hematopoietic Stem Cell Transplantation

In recent years, vancomycin-resistant Enterococcus (VRE) colonization is being increasingly encountered in transplant recipients, and VRE has become one of the leading causes of bacteremia early after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Data are sparse on the effect of empiric VRE therapy for febrile, neutropenic allo-HSCT recipients colonized with VRE. All allo-HSCT recipients aged ≥18years who developed VRE bacteremia (VREB) between 2005 and 2014 were identified and categorized as to whether they received empiric or directed VRE therapy. There were 434 (33%) VRE-colonized and 872 (67%) non-VRE-colonized patients during the study period, and 172 of the 434 (40%) VRE-colonized patients received empiric therapy. There was no significant difference in incidence of VREB among colonized patients who did or did not receive empiric therapy (28 of 172 [16%] vs 55 of 262 [21%]; P = .22). There were 95 patients with VREB, of which the majority (83 of 95; 87%) was known to be VRE-colonized. Of the 95 VREB episodes, 29 (31%) were treated with empiric VRE therapy, whereas 66 (69%) were treated with directed therapy. No significant differences in clinical outcomes, including median duration of bacteremia (2 days vs 2 days; P = .39), recurrent VREB (3 of 29 [10%] vs 5 of 66 [8%]; P = .65), 30-day all-cause mortality (1 of 29 [3%] vs 4 of 66 [6%]; P = .62), or VRE-attributable mortality (1 of 29 [3%] vs 1 of 66 [2%]; P = .55), were observed between the empiric therapy and directed therapy groups. Kaplan-Meier curve analysis showed no significant difference in survival at 30days in allo-HSCT recipients with VREB who received empiric therapy and those who received directed therapy (97% vs 94%; P = .62). Based on our data, we recommend against empiric use of VRE-active agents for fever and neutropenia in VRE-colonized patients undergoing allo-HSCT.

Vancomycin-resistant enterococci (VRE): a reason to isolate?

In recent years, an increase in invasive VRE infections has been reported worldwide, including Germany. The most common gene encoding resistance to glycopeptides is VanA, but predominant VanB clones are emerging. Although neither the incidence rates nor the exact routes of nosocomial transmission of VRE are well established, screening and strict infection control measures, e.g. single room contact isolation, use of personal protective clothing by hospital staff and intensified surface disinfection for colonized individuals, are implemented in many hospitals. At the same time, the impact of VRE infection on mortality remains unclear, with current evidence being weak and contradictory. In this short review, we aim to give an overview on the current basis of evidence on the clinical effectiveness of infection control measures intended to prevent transmission of VRE and to put these findings into a larger perspective that takes further factors, e.g. VRE-associated mortality and impact on patient care, into account.

Hospital acquired vancomycin resistant enterococci in surgical intensive care patients - a prospective longitudinal study

Background

Vancomycin resistant enterococci (VRE) occur with enhanced frequency in hospitalised patients. This study elucidates the prevalence of VRE on admission among surgical intensive care unit (SICU) patients, whether these patients are at special risk for VRE acquisition and which risk factors support this process.

Methods

Patients admitted to SICUs of the University Hospital Münster were examined during August-October 2017. VRE screening was performed within 48 h after admission and directly prior to discharge of patients. In parallel risk factors were recorded to estimate their effect on VRE acquisition during SICU stay.

Results

In total, 374 patients (68% male) with a median age of 66 years were admitted to one of the SICUs during the investigation period. Of all, 336 patients (89.8%) were screened on admission and 268 (71.7%) on discharge. Nine patients were admitted with previously known VRE colonisation. Twelve (3.6%) further patients were VRE positive on admission. During ICU stay, eight (3.0%) additional patients turned out to be VRE colonised. Risk factors found to be significantly associated with VRE acquisition were median length of stay on the ICU (14 vs. 3 days; p = 0.01), long-term dialysis (12.5% vs. 2.0% of patients; p = 0.05), and antibiotic treatment with flucloxacillin (28.6% vs. 7.2% of patients; p = 0.01) or piperacillin/tazobactam (57.1% vs. 26.6% of patients; p = 0.01).

Conclusions

SICU patients are not at special risk for VRE acquisition. Previous stay on a SICU should therefore not be considered as specific risk factor for VRE colonisation.

Timepoints of vancomycin-resistant Enterococcus colonization predict outcomes of acute myeloid leukemia patients undergoing allogeneic hematopoietic cell transplantation

BACKGROUND

In hematology and oncology, in particular in the setting of allogeneic hematopoietic stem cell transplantation (allo-HSCT), vancomycin-resistant Enterococcus spp. (VRE) colonization rates are high due to previous hospital stays and preceding antibiotic treatment and colonized patients have a lower overall survival (OS).

OBJECTIVE

We reanalyzed our previously published cohort, to unravel which colonization timepoints before and during allo-HSCT might be predictive for the subsequent outcome.

PATIENTS AND METHODS

We report about 268 patients with acute myeloid leukemia receiving an allo-HSCT between 2006 and 2016.

RESULTS

We identified 129 never-colonized patients, 15 previously colonized patients (positive only before admission for allo-HSCT), 41 persistently colonized patients (positive before and at admission for allo-HSCT), and 83 newly colonized patients (positive only during allo-HSCT). Persistently and newly colonized patients had a worse 60 months OS due to increased incidence of non-relapse-related mortality (NRM) than never-colonized patients (OS: never-colonized: 61.0% vs persistently colonized: 43.5%; P = 0.023 vs newly colonized: 45.6%; P = 0.046). In contrast, OS and NRM of never-colonized and previously colonized patients as well as between persistently and newly colonized patients were similar.

CONCLUSION

Patients can lose their VRE colonization status and acquisition of VRE during inpatient stay for allo-HSCT decreases survival to a similar extend as persistent colonization.

Prediction of Bloodstream Infection Due to Vancomycin-Resistant Enterococcus in Patients Undergoing Leukemia Induction or Hematopoietic Stem-Cell Transplantation

Background.

Bloodstream infection (BSI) to due vancomycin-resistant Enterococcus (VRE) is an important complication of hematologic malignancy. Determining when to use empiric anti-VRE antibiotic therapy in this population remains a clinical challenge.

Methods.

A single-center cohort representing 664 admissions for induction or hematopoietic stem-cell transplant (HSCT) from 2006 to 2014 was selected. We derived a prediction score using risk factors for VRE BSI and evaluated the model's predictive performance by calculating it for each of 16232 BSI at-risk inpatient days.

Results.

VRE BSI incidence was 6.5% of admissions (2.7 VRE BSI per 1000 BSI at-risk days). Adjusted 1-year mortality and length of stay were significantly higher in patients with VRE BSI. VRE colonization (adjusted odds ratio [aOR] = 8.4; 95% confidence interval [CI] = 3.4-20.6; P < .0001), renal insufficiency (aOR = 2.4; 95% CI = 1.0-5.8; P = .046), aminoglycoside use (aOR = 4.7; 95% CI = 2.2-9.8; P < .0001), and antianaerobic antibiotic use (aOR = 2.8; 95% CI = 1.3-5.8; P = .007) correlated most closely with VRE BSI. A prediction model with optimal performance included these factors plus gastrointestinal disturbance, severe neutropenia, and prior beta-lactam antibiotic use. The score effectively risk-stratified patients (area under the receiver operating curve = 0.84; 95% CI = 0.79-0.89). At a threshold of ≥5 points, per day probability of VRE BSI was increased nearly 4-fold.

Conclusions.

This novel predictive score is based on risk factors reflecting a plausible pathophysiological model for VRE BSI in patients with hematological malignancy. Integrating VRE colonization status with risk factors for developing BSI is a promising method of guiding rational use of empiric anti-VRE antimicrobial therapy in patients with hematological malignancy. Validation of this novel predictive score is needed to confirm clinical utility.

Pretransplant Gut Colonization with Intrinsically Vancomycin-Resistant Enterococci (E. gallinarum and E. casseliflavus) and Outcomes of Allogeneic Hematopoietic Cell Transplantation

Pretransplant gut colonization with intrinsically vancomycin-resistant enterococci (iVRE) (Enterococcus gallinarum and Enterococcus casseliflavus) is uncommon and with unknown clinical impact. In a matched-pairs analysis of patients with versus without iVRE colonization (n = 18 in each group), we demonstrated significantly higher 2-year overall survival (86% [95% confidence interval, 52% to 96%] versus 35% [95% confidence interval, 8% to 65]; P <.01) and lower nonrelapse mortality (P <.01) among colonized patients. Putative metabolomes differentiated iVRE from E. faecalis/faecium and may contribute to a healthier gut microbiome in iVRE-colonized patients.

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.

Multidrug-resistant Enterobacteriaceae, Pseudomonas aeruginosa, and vancomycin-resistant Enterococcus: Three major threats to hematopoietic stem cell transplant recipients

Hematopoietic stem cell transplant (HSCT) recipients are uniquely threatened by the emergence of multidrug-resistant (MDR) bacteria because these patients rely on immediate active antimicrobial therapy to combat bacterial infections. This review describes the epidemiology and treatment considerations for three challenging MDR bacterial pathogens in HSCT recipients: MDR Enterobacteriaceae, including extended-spectrum β-lactamase (ESBL)-producing and carbapenem-resistant Enterobacteriaceae (CRE), Pseudomonas aeruginosa, and vancomycin-resistant Enterococcus (VRE). These bacteria are common causes of infection in this population and bacteremias caused by these organisms are associated with high mortality rates. Carbapenems remain the treatments of choice for serious infections due to ESBL-producing Enterobacteriaceae in HSCT recipients. Administration of β-lactam agents as an extended infusion is associated with improved outcomes in patients with severe infections caused by P. aeruginosa. Older agents used for the treatment of CRE and MDR P. aeruginosa infections, such as polymyxins and aminoglycosides, have major limitations. Newer agents, such as ceftazidime-avibactam and ceftolozane-tazobactam have great potential for the treatment of Klebsiella pneumoniae carbapemenase-producing CRE and MDR P. aeruginosa, respectively, but more pre-clinical and clinical data are needed to better evaluate their efficacy. Daptomycin dosages ≥8 mg/kg/day are recommended to treat VRE infections in this population, particularly in the setting of increasing daptomycin resistance. Strategies to prevent these infections include strict adherence to recommended infection control practices and multidisciplinary antimicrobial stewardship. Last, gastrointestinal screening to guide empirical therapy and the use of polymerase chain reaction-based rapid diagnostics may decrease the time to administration of appropriate therapy for these infections, thereby leading to improved outcomes.