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

The impact of colonization by multidrug resistant bacteria on graft survival, risk of infection, and mortality in recipients of solid organ transplant: systematic review and meta-analysis

BACKGROUND

The Global increase in colonization by multidrug-resistant (MDR) bacteria poses a significant concern. The precise impact of MDR colonization in solid organ transplant recipients (SOTR) remains not well established.

OBJECTIVES

To assess the impact of MDR colonization on SOTR's mortality, infection, or graft loss.

METHODS AND DATA SOURCES

Data from PROSPERO, OVID Medline, OVID EMBASE, Wiley Cochrane Library, ProQuest Dissertations, Theses Global, and SCOPUS were systematically reviewed, spanning from inception until 20 March 2023. The study protocol was registered with PROSPERO (CRD42022290011) and followed the PRISMA guidelines. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, INTERVENTIONS, AND ASSESSMENT OF RISK OF BIAS: Cohorts and case-control studies that reported on adult SOTR colonized by Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum β-lactamase (ESBL) or carbapenem-resistant Enterobacteriaceae. (CRE), or MDR-pseudomonas, and compared to noncolonized, were included. Two reviewers assessed eligibility, conducted a risk of bias evaluation using the Newcastle-Ottawa Scale, and rated certainty of evidence using the GRADE approach.

METHODS OF DATA SYNTHESIS

We employed RevMan for a meta-analysis, using random-effects models to compute pooled odds ratios (OR) and 95% confidence intervals (CI). Statistical heterogeneity was determined using the I2 statistic.

RESULTS

15,202 SOTR (33 cohort, six case-control studies) were included, where liver transplant and VRE colonization (25 and 14 studies) were predominant. MDR colonization significantly increased posttransplant 1-year mortality (OR, 2.35; 95% CI, 1.63-3.38) and mixed infections (OR, 10.74; 95% CI, 7.56-12.26) across transplant types (p < 0.001 and I2 = 58%), but no detected impact on graft loss (p 0.41, I2 = 0). Subgroup analysis indicated a higher association between CRE or ESBL colonization with outcomes (CRE: death OR, 3.94; mixed infections OR, 24.8; ESBL: mixed infections OR, 10.3; no mortality data) compared to MRSA (Death: OR, 2.25; mixed infection: OR, 7.75) or VRE colonization (Death: p 0.20, mixed infections: OR, 5.71).

CONCLUSIONS

MDR colonization in SOTR, particularly CRE, is associated with increased mortality. Despite the low certainty of the evidence, actions to prevent MDR colonization in transplant candidates are warranted.

Are enterococcal bloodstream infections an independent risk factor for a poorer 5-year survival or just a marker for severity of illness?-The Munich multicentric enterococci cohort

IMPORTANCE

The present study provides a substantial contribution to literature, showing that patients with enterococcal bloodstream infections (BSI) have a lower survival rate than those with Escherichia coli (E. coli) bloodstream infections after adjusting for 17 limiting prognostic factors and excluding patients with a limited life expectancy [metastatic tumor disease, Charlson Comorbidity Index (CCI) (greater than or equal to) 5]. This difference in the 5-year long-term survival was mainly driven by Enterococcus faecium (ECFM) bloodstream infections, with vancomycin resistance not being a significant contributing factor. Our findings imply that E. faecium bloodstream infections seem to be an independent risk factor for poor long-term outcomes. As such, future research should confirm this relationship and prioritize investigating its causality through prospective studies.

Vancomycin resistant enterococcus risk factors for hospital colonization in hematological patients: a matched case-control study

BACKGROUND

Vancomycin-resistant enterococcus (VRE) was the fastest growing pathogen in Europe in 2022 (+ 21%) but its clinical relevance is still unclear. We aim to identify risk factors for acquired VRE rectal colonization in hematological patients and evaluate the clinical impact of VRE colonization on subsequent infection, and 30- and 90-day overall mortality rates, compared to a matched control group.

METHODS

A retrospective, single center, case-control matched study (ratio 1:1) was conducted in a hematological department from January 2017 to December 2020. Case patients with nosocomial isolation of VRE from rectal swab screening (≥ 48 h) were matched to controls by age, sex, ethnicity, and hematologic disease. Univariate and multivariate logistic regression compared risk factors for colonization.

RESULTS

A total of 83 cases were matched with 83 controls. Risk factors for VRE colonization were febrile neutropenia, bone marrow transplant, central venous catheter, bedsores, reduced mobility, altered bowel habits, cachexia, previous hospitalization and antibiotic treatments before and during hospitalization. VRE bacteraemia and Clostridioides difficile infection (CDI) occurred more frequently among cases without any impact on 30 and 90-days overall mortality. Vancomycin administration and altered bowel habits were the only independent risk factors for VRE colonization at multivariate analysis (OR: 3.53 and 3.1; respectively).

CONCLUSIONS

Antimicrobial stewardship strategies to reduce inappropriate Gram-positive coverage in hematological patients is urgently required, as independent risk factors for VRE nosocomial colonization identified in this study include any use of vancomycin and altered bowel habits. VRE colonization and infection did not influence 30- and 90-day mortality. There was a strong correlation between CDI and VRE, which deserves further investigation to target new therapeutic approaches.

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.

Colonization by multidrug-resistant bacteria in hematological patients undergoing hematopoietic stem cell transplantation and clinical outcomes: A single-center retrospective cohort study

BACKGROUND

Bloodstream infections are a leading cause of death in patients who undergo hematopoietic stem cell transplantation (HSCT) and are more severe when caused by multidrug-resistant (MDR) bacteria. This study proposed to investigate if colonization by MDR bacteria negatively affects the clinical outcomes in hematological patients after HSCT, as well as to evaluate possible risk factors for death due to bacteremia by the same colonizing agent.

METHODS

A single-center retrospective cohort study was conducted with 405 hematological patients submitted to a single HSCT procedure between 2015 and 2021. Patients were classified as colonized (n = 132) or noncolonized (n = 273) based on the surveillance cultures from D-30 to D+30 of transplantation, and their relevant clinical and laboratory data were collected until D+100.

RESULTS

Colonization by MDR bacteria increased blood culture positivity by all micro-organisms and also specifically by MDR bacteria, with a more pronounced effect when caused by carbapenemase-producing Klebsiella pneumoniae. Patients colonized with carbapenem-resistant K. pneumoniae had increased overall mortality (HR = 4.07, 95% CI 1.85-8.91, P = .0005) and had prolonged hospital length of stay in the context of autologous transplantation. Risk factors for death due to bacteremia by the same colonizing agent were neutropenia, colonization by carbapenem-resistant K. pneumoniae and use of high-dose total body irradiation in conditioning.

CONCLUSION

Hematological patients colonized by MDR bacteria presented a higher incidence of bloodstream infections, and colonization by carbapenemase-producing K. pneumoniae was associated with reduced overall survival.

Comparison of Risk Stratification Approaches to Identify Patients with Clostridioides difficile Infection at Risk for Multidrug-Resistant Organism Gut Microbiota Colonization

INTRODUCTION

Multidrug-resistant organisms (MDRO) commonly colonize the gut microbiota of patients with Clostridioides difficile infection (CDI). This increases the likelihood of systemic infections with these MDROs. To help guide MDRO screening and/or empiric antibiotic therapy, we derived and compared predictive indices for MDRO gut colonization in patients with CDI.

METHODS

This was a multicenter, retrospective cohort study of adult patients with CDI from July 2017 to April 2018. Stool samples were screened for MDRO via growth and speciation on selective antibiotic media and confirmed using resistance gene polymerase chain reaction. A regression-based risk score for MDRO colonization was constructed. Predictive performance via area under the receiver operating characteristic curve (aROC) of this index was compared with two other simplified risk stratification approaches: (1) prior healthcare exposure and/or high-CDI risk antibiotics; (2) number of prior high-CDI risk antibiotics.

RESULTS

50 (20.8%) of 240 included patients had MDRO colonization; 35 (14.6%) VRE, 18 (7.5%) MRSA, 2 (0.8%) CRE. Prior fluoroquinolone (aOR 2.404, 95% CI 1.095-5.279) and prior vancomycin (1.996, 95% CI 1.014-3.932) were independently associated with MDRO colonization while prior clindamycin (aOR 3.257, 95% CI 0.842-12.597) and healthcare exposure (aOR 2.138, 95% CI 0.964-4.740) were retained as explanatory variables. The regression-based risk score significantly predicted MDRO colonization (aROC 0.679, 95% CI 0.595-0.763), but was not significantly more predictive than prior healthcare exposure + prior antibiotics (aROC 0.646, 95% CI 0.565-0.727) or number of prior antibiotic exposures (aROC 0.642, 95% CI 0.554-0.730); P > 0.05 for both comparisons.

CONCLUSION

A simplified approach using prior healthcare exposure and receipt of prior antibiotics known to increase CDI risk identified patients at risk for MDRO gut microbiome colonization as effectively as individual patient/antibiotic risk modeling.

Increasing trend in enterococcal bacteraemia and vancomycin resistance in a tertiary care hospital in Croatia, 2017-2021

BACKGROUND

The epidemiology of enterococcal bacteraemia has changed worldwide and vancomycin-resistant enterococci increasingly cause healthcare-associated infections) with limited treatment options. Studies show heterogeneity among countries, regions and individual hospitals.

METHODS

We retrospectively analysed enterococcal bacteraemia with Enterococcus faecalis and E. faecium at the largest hospital in Croatia, University Hospital Centre Zagreb from January 2017 to December 2021.

RESULTS

A total of 432 cases of enterococcal bacteraemia were identified with 256 (59.3%) due to E. faecalis and 176 (40.7%) to E. faecium. Enterococcal bacteraemia occurred more frequently in men (n = 270; 62.5%) and the median age of all patients was 62 years (IQR: 0-92). We found statistically significant increase in the incidence trend of bacteraemic episodes with an annual percent change of 20.9% (95% confidence interval 14.3 to 27.8; p = .002) predominantly due to an increase of E. faecalis bacteraemia. The majority of patients (362/432; 83.8%) had healthcare-associated infections and 38.0% (165/432) of patients were in the intensive care unit. The proportion of vancomycin-resistant enterococcal bacteraemia increased from 12.7% (n = 8/63) in 2017 to 25.7% (n = 29/113) in 2021, statistically significant increasing trend (p = .0455), mainly due to an increased proportion of vancomycin-resistant E. faecium (p = .0169).

CONCLUSIONS

This is the first study describing the trends in enterococcal bacteraemia and vancomycin-resistance in enterococci in Croatia. We found a rising trend in enterococcal bacteraemia and in the proportion of vancomycin resistance and identified the most vulnerable patient groups, notably intensive care unit patients.

Infection prevention requirements for the medical care of immunosuppressed patients: recommendations of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute

In Germany, guidelines for hygiene in hospitals are given in form of recommendations by the Commission for Hospital Hygiene and Infection Prevention (Kommission für Krankenhaushygiene und Infektionsprävention, "KRINKO"). The KRINKO and its voluntary work are legitimized by the mandate according to § 23 of the Infection Protection Act (Infektionsschutzgesetz, "IfSG"). The original German version of this document was published in February 2021 and has now been made available to the international professional public in English. The guideline provides recommendations on infection prevention and control for immunocompromised individuals in health care facilities. This recommendation addresses not only measures related to direct medical care of immunocompromised patients, but also management aspects such as surveillance, screening, antibiotic stewardship, and technical/structural aspects such as patient rooms, air quality, and special measures during renovations.

Enterococcal bacteremia in mice is prevented by oral administration of probiotic Bacillus spores

Whether and how probiotics promote human health is a controversial issue. Their claimed benefit for counteracting gastrointestinal infection is linked predominantly to reducing pathogen abundance within the intestinal microbiota. Less understood mechanistically is the reported value that probiotics could have in reducing systemic infections. Enterococcus faecalis is an opportunistic pathogen that causes systemic infection after translocation through the intestinal epithelium, particularly in hospitalized and immune-depleted patients receiving antibiotic therapy. In this study, we used an E. faecalis mouse infection model with wild-type and isogenic mutant strains deficient in genes of the E. faecalis Fsr (fecal streptococci regulator) quorum-sensing system. We show that E. faecalis translocation from the mouse gut into the blood is mediated by the Fsr quorum-sensing system through production of the protease GelE, which compromises intestinal epithelium integrity. Furthermore, we demonstrate that orally administered probiotic Bacillus subtilis spores blocked E. faecalis translocation from the gut to the bloodstream and subsequent systemic infection in mice by inhibiting Fsr activity. These findings demonstrate that a key aspect of Enterococcus pathogenesis is controlled by quorum sensing, which can be targeted with probiotic Bacillus spores.

Sequence type 17 is a predictor of subsequent bacteremia in vancomycin-resistant Enterococcus faecium-colonized patients: a retrospective cohort study

Background

Sequence type (ST) 17 vancomycin-resistant Enterococcus faecium (VREF) is frequently isolated in nosocomial settings. The aim of this study was to identify whether ST17 contributes to subsequent bacteremia more often than other STs among hospitalized patients carrying VREF.

Methods

A retrospective cohort study was conducted in patients carrying ST17 VREF and those with non-ST17 VREF. Rectal screening according to hospital policy was used to identify patients with VREF. Subsequent VREF bacteremia events within a year of detection of colonization were recorded. Cox regression analysis was used to adjust the covariates involved in determining the association between ST17 and subsequent bacteremia events.

Results

The cohorts comprised 52 patients with ST17 and 169 patients with non-ST17 VREF. One-year VREF bacteremia-free rates were 85.9% and 90.2%, respectively. In multivariate analysis, ST17 was associated with subsequent bacteremia at an adjusted hazard risk (aHR) of 4.02 (95% confidence interval [CI], 1.32–12.29). Liver transplantation (aHR, 40.08; 95% CI, 4.87–329.76) and hematologic malignancy (aHR, 20.97; 95% CI, 4.87–87.82) were also significant. All cases of subsequent bacteremia in ST17 VREF carriers were caused by ST17; however, subsequent bacteremia in non-ST17 carriers was often caused by ST17 or another ST variant.

Conclusions

A specific genotype, ST17 is a predictor of subsequent bacteremia in hospitalized patients carrying VREF. Patients with a hematologic malignancy and those receiving a liver transplant are also at high risk. More targeted strategies may be needed to prevent VREF infection in hospitals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-021-00980-1.

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.

Pharmacogenetics-Based Preliminary Algorithm to Predict the Incidence of Infection in Patients Receiving Cytotoxic Chemotherapy for Hematological Malignancies: A Discovery Cohort

Introduction: Infections in hematological cancer patients are common and usually life-threatening; avoiding them could decrease morbidity, mortality, and cost. Genes associated with antineoplastics’ pharmacokinetics or with the immune/inflammatory response could explain variability in infection occurrence.

Objective: To build a pharmacogenetic-based algorithm to predict the incidence of infections in patients undergoing cytotoxic chemotherapy.

Methods: Prospective cohort study in adult patients receiving cytotoxic chemotherapy to treat leukemia, lymphoma, or myeloma in two hospitals in Santiago, Chile. We constructed the predictive model using logistic regression. We assessed thirteen genetic polymorphisms (including nine pharmacokinetic—related genes and four inflammatory response-related genes) and sociodemographic/clinical variables to be incorporated into the model. The model’s calibration and discrimination were used to compare models; they were assessed by the Hosmer-Lemeshow goodness-of-fit test and area under the ROC curve, respectively, in association with Pseudo-R².

Results: We analyzed 203 chemotherapy cycles in 50 patients (47.8 ± 16.1 years; 56% women), including 13 (26%) with acute lymphoblastic and 12 (24%) with myeloblastic leukemia.

Pharmacokinetics-related polymorphisms incorporated into the model were CYP3A4 rs2242480C>T and OAT4 rs11231809T>A. Immune/inflammatory response-related polymorphisms were TLR2 rs4696480T>A and IL-6 rs1800796C>G. Clinical/demographic variables incorporated into the model were chemotherapy type and cycle, diagnosis, days in neutropenia, age, and sex. The Pseudo-R² was 0.56, the p-value of the Hosmer-Lemeshow test was 0.98, showing good goodness-of-fit, and the area under the ROC curve was 0.93, showing good diagnostic accuracy.

Conclusions: Genetics can help to predict infections in patients undergoing chemotherapy. This algorithm should be validated and could be used to save lives, decrease economic costs, and optimize limited health resources.

Colonization with multi-drug-resistant organisms negatively impacts survival in patients with non-small cell lung cancer

Objectives

Multidrug-resistant organisms (MDRO) are considered an emerging threat worldwide. Data covering the clinical impact of MDRO colonization in patients with solid malignancies, however, is widely missing. We sought to determine the impact of MDRO colonization in patients who have been diagnosed with Non-small cell lung cancer (NSCLC) who are at known high-risk for invasive infections.

Materials and methods

Patients who were screened for MDRO colonization within a 90-day period after NSCLC diagnosis of all stages were included in this single-center retrospective study.

Results

Two hundred and ninety-five patients were included of whom 24 patients (8.1%) were screened positive for MDRO colonization (MDRO^pos) at first diagnosis. Enterobacterales were by far the most frequent MDRO detected with a proportion of 79.2% (19/24). MDRO colonization was present across all disease stages and more present in patients with concomitant diabetes mellitus. Median overall survival was significantly inferior in the MDRO^pos study group with a median OS of 7.8 months (95% CI, 0.0–19.9 months) compared to a median OS of 23.9 months (95% CI, 17.6–30.1 months) in the MDRO^neg group in univariate (p = 0.036) and multivariate analysis (P = 0.02). Exploratory analyses suggest a higher rate of non-cancer-related-mortality in MDRO^pos patients compared to MDRO^neg patients (p = 0.002) with an increased rate of fatal infections in MDRO^pos patients (p = 0.0002).

Conclusions

MDRO colonization is an independent risk factor for inferior OS in patients diagnosed with NSCLC due to a higher rate of fatal infections. Empirical antibiotic treatment approaches should cover formerly detected MDR commensals in cases of (suspected) invasive infections.

An Update to Enterococcal Bacteremia: Epidemiology, Resistance, and Outcome

BACKGROUND

An increase in resistant gram-positive cocci, especially enterococci, requires an epidemiologic re-assay and its results may affect empirical treatments for these infections.

OBJECTIVE

In this study, we investigated the microbial epidemiology and resistance pattern of enterococcal bacteremia.

METHODS

This study was a cross-sectional study that investigates all cases of positive blood cultures with Enterococcus spp. at a tertiary referral colligates hospital in Tehran in 2018.

RESULTS

Enterococcus spp. was isolated from blood cultures of a total of 73 patients. The most patients were male 42 (57.7%). The mean age of the patients was 58.8 (±18.8) years. Hospital-acquired infection was the most type of infection involving enterococcal bacteremia (80.8%) comparing with community-acquired (6.7%) and health care-associated (12.3%). Renal failure and cancer were the most underlying disease in E. faecalis and E. faecium, respectively. Mortality for Vanco-mycin-resistant enterococci (VRE) was approximately two times more than the sensitive ones. Between the dead/alive groups, the following items were different significantly (P.Value<0.05): Vancomycin resistance for enterococcus isolated, immunodeficiency as underlying disease, Mechanical ventilation, hospitalization period, and the empiric regimen.

CONCLUSION

Increased antibiotic-resistant strains, especially Vancomycin-resistant enterococci (VRE), pose a serious threat to the general public, especially hospitalized patients, and increase mortality. Surveillance of microorganisms and antimi-crobial resistance is a crucial part of an efficient health care system.

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.

Clinical Characteristics and Risk Factors for Bloodstream Infection Due to Carbapenem-Resistant Klebsiella pneumoniae in Patients with Hematologic Malignancies

Purpose

The aim was to examine the clinical characteristics and risk factors for bloodstream infection (BSI) due to carbapenem-resistant Klebsiella pneumoniae (CRKP) in patients with hematologic malignancies.

Materials and Methods

A single-centre, retrospective case–control study representing 734 patients with hematologic malignancies between January 1, 2017, and December 31, 2018, was conducted. Demographic and clinical data were collected from the hospital electronic medical records system.

Results

Among the 734 patients with hematologic malignancies, 3% (22/734) of the patients developed CRKP BSI during their hospitalization. Overall 28-day all-cause mortality reached 77.3% (17/22). Patients with Pitt bacteremia score (PBS) >4, pneumonia and septic shock were more frequent in the non-survivors versus the survivors. Compared with the non-survivors in antimicrobial treatment, combination therapy of tigecycline and polymyxin B was more common in the survivors. The independent risk factors associated with CRKP BSI were CRKP rectal colonization (OR, 11.067; CI=4.43–27.644; P<0.001; 3 points), severe neutropenia (OR, 4.095; CI=0.876–19.141; P=0.073; 1 point) and invasive mechanical ventilation (IMV) within the previous 30 days to onset of BSI (OR, 18.444; CI=1.787–190.343; P=0.014; 4 points). The total risk score of ≥5 indicated that the probability of CRKP BSI occurrence was above 48%.

Conclusion

CRKP BSI in patients with hematologic malignancies is associated with high mortality. The risk factor-based prediction model might help clinicians to start prompt effective anti-infective therapy in patients with suspicion of CRKP BSI and improve outcomes.

A Baker's Dozen of Top Antimicrobial Stewardship Intervention Publications in 2019

Staying current on literature related to antimicrobial stewardship can be challenging given the ever-increasing number of published articles. The Southeastern Research Group Endeavor (SERGE-45) identified antimicrobial stewardship–related peer-reviewed literature that detailed an actionable intervention for 2019. The top 13 publications were selected using a modified Delphi technique. These manuscripts were reviewed to highlight the actionable intervention used by antimicrobial stewardship programs to provide key stewardship literature for teaching and training and to identify potential intervention opportunities within one’s institution.

Microbiota-based approaches to mitigate infectious complications of intensive chemotherapy in patients with acute leukemia

Despite advances in antimicrobial treatments, infection remains a common complication of intensive chemotherapy in patients with acute leukemia. It has become progressively apparent that the current antimicrobial focus has shortcomings that result from disruption of the commensal microbial communities of the gut. These effects, collectively known as dysbiosis, have been increasingly associated worldwide with growing complications such as Clostridioides difficile infection, systemic infections, and antibiotic resistance. A revision of the current practice is overdue. Several innovative concepts have been proposed and tested in animal models and humans, with the overarching goal of preventing damage to the microbiota and facilitating its recovery. In this review, we discuss these approaches, examine critical knowledge gaps, and explore how they may be filled in future research.

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.

Using VRE screening tests to predict vancomycin resistance in enterococcal bacteremia

BACKGROUND AND OBJECTIVE

Enterococcus causes clinically significant bloodstream infections (BSIs). In centers with a higher prevalence of vancomycin resistant enterococcus (VRE) colonization, a common clinical question is whether empiric treatment directed against VRE should be initiated in the setting of a suspected enterococcal BSI. Unfortunately, VRE treatment options are limited, and relatively expensive, and subject patients to the risk of adverse reactions. We hypothesized that the results of VRE colonization screening could predict vancomycin resistance in enterococcal BSI.

METHODS

We reviewed 370 consecutive cases of enterococcal BSI over a 7-year period at 2 tertiary-care hospitals to determine whether vancomycin-resistant BSIs could be predicted based on known colonization status (ie, patients with swabs performed within 30 days, more remotely, or never tested). We calculated sensitivity and specificity, and we plotted negative predictives values (NPVs) and positive predictive values (PPVs) as a function of prevalence.

RESULTS

A negative screening swab within 30 days of infection yielded NPVs of 90% and 95% in settings where <27.0% and 15.0% of enterococcal BSI are resistant to vancomycin, respectively. In patients with known VRE colonization, the PPV for VRE in enterococcal BSI was >50% at any prevalence exceeding 25%.

CONCLUSIONS

The results of a negative VRE screening test result performed within 30 days can help eliminate unnecessary empiric therapy in patients with suspected enterococcal BSI. Conversely, patients with positive VRE screening swabs require careful consideration of empiric VRE-directed therapy when enterococcal BSI appears likely.

Neutropenic Fever in the Intensive Care Unit

Neutropenic fever is a common and potentially life-threatening condition in patients treated for cancer. Rapid initiation of appropriate antimicrobial therapy is necessary to decrease the risk of mortality. Most infections are due to gram-positive organisms, but the mortality rate is higher for gram-negative infections. Multidrug-resistant organisms are an emerging threat to neutropenic patients. Increasing data suggest that the pathophysiology of neutropenic fever and neutropenic sepsis is substantially different from non-neutropenic fever and sepsis. Additional research is needed to both further elucidate the pathogenesis of neutropenic fever and to develop additional effective antimicrobials.

Gut dysbiosis during antileukemia chemotherapy versus allogeneic hematopoietic cell transplantation

BACKGROUND

In the field of malignant hematology, most microbiome studies have focused on recipients of allogeneic hematopoietic cell transplantation (allo-HCT). As a result, this population has remained the primary target for novel microbiota therapeutics. Because the types of insults to the microbiome are similar during hematopoietic cell transplantation and intensive antileukemia therapy, this study evaluated whether the dysbiosis states are similar in the 2 settings.

METHODS

This study compared gut microbiota assemblages and community domination states in 2 cohorts of patients: patients with intensively treated acute leukemia (AL) and allo-HCT recipients. 16S ribosomal RNA gene profiling of thrice weekly stool samples was performed. Linear discriminant analysis effect size was used to determine differentially abundant taxa in groups of interest, and mixed modes were used to determine the predictors of microbiome states.

RESULTS

Microbiome changes in both cohorts were characterized by a marked loss of diversity and domination of low-diversity communities by Enterococcus. In the AL cohort, the relative abundance of Lactobacillus was also inversely correlated with diversity. Communities dominated by these genera were compositionally different.

CONCLUSIONS

Similarities in microbiota assemblages between the 2 cohorts support a broader scope for microbiota-directed therapeutics than previously considered, whereas specific differences suggest a personalized aspect to such therapeutics with the possibility of a differential response.

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.

Early Detection of Bacteraemia Using Ten Clinical Variables with an Artificial Neural Network Approach

An adequate model for predicting bacteraemia has not yet been developed. This study aimed to evaluate the performance of an artificial neural network (ANN)-based prediction model in comparison with previous statistical models. The performance of multi-layer perceptron (MLP), a representative ANN model, was verified via comparison with a non-neural network model. A total of 1260 bacteraemia episodes were identified in 13,402 patients. In MLP with 128 hidden layer nodes, the area under the receiver operating characteristic curve (AUC) of the prediction performance was 0.729 (95% confidence interval [CI]; 0.712–0.728), while in MLP with 256 hidden layer nodes, it was 0.727 (95% CI; 0.713–0.727). In a conventional Bayesian statistical method, the AUC was 0.7. The aforementioned two MLP models exhibited the highest sensitivity (0.810). The ranking of clinical variables was used to describe the influential power of the prediction. Serum alkaline phosphatase was one of the most influential clinical variables, and one-out search was the best ranking method for measuring the influence of the clinical variables. Furthermore, adding variables beyond the 10 top-ranking ones did not significantly affect the prediction of bacteraemia. The ANN model is not inferior to conventional statistical approaches. Bacteraemia can be predicted using only the top 10 clinical variables determined by a ranking method, and the model can be used in clinical practice by applying real-time monitoring.

Aztreonam and Vancomycin for Initial Treatment of Febrile Neutropenia in Penicillin-Allergic Patients During Hematopoietic Stem Cell Transplantation

Most patients who undergo hematopoietic stem cell transplantation develop neutropenic fever and are at high risk for developing potentially life-threatening infections. β-lactam antibiotics remain the cornerstone for initial empiric treatment of neutropenic fever. In cancer patients with allergy or intolerance to β-lactams, guidelines recommend using aztreonam with vancomycin (AV) for neutropenic fever treatment. To date, the efficacy of AV for the treatment of neutropenic fever during stem cell transplantation is unknown. A retrospective study was conducted to identify hematopoietic stem cell transplantation recipients who were initially treated with concomitant AV for neutropenic fever between 2007 and 2013. Febrile neutropenia was classified as neutropenia with unexplained fever, neutropenic fever with a local source of infection, or neutropenic fever with a microbiologically documented infection. Seventy-six patients were identified who received AV as initial treatment for neutropenic fever over the study period. Responses to AV for neutropenia with unexplained fever (n = 41), febrile neutropenia with local site of infection (n = 11 [pneumonia = 9, other = 2]), and neutropenic fever with microbiologically documented infection (n = 34) were 75%, 55% (45% pneumonia), and 46% respectively. Infection-related mortality was 5%. Aztreonam with vancomycin was effective in treating neutropenia with unexplained fever. For patients with neutropenic fever and local source or microbiologically documented infection, alternative antibiotic treatments should be considered.

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.

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.

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.

Unintended Consequences of Pretransplant Vancomycin-Resistant Enterococcus Screening on Antimicrobial Stewardship Among Allogeneic Hematopoietic Cell Transplant Recipients

We examined vancomycin-resistant enterococci (VRE)-directed antimicrobial use and VRE bacteremia in a cohort of allogeneic hematopoietic cell transplantation patients from a center where VRE screening is standard prior to transplant. In this cohort, VRE bacteremia (VREB) was infrequent. In patients without VREB, colonized patients received VRE therapy more often than noncolonized patients.Infect Control Hosp Epidemiol 2018;39:730-733.

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.