Colonization, bloodstream infection, and mortality caused by vancomycin-resistant enterococcus early after allogeneic hematopoietic stem cell transplant

Risk for development of vancomycin resistant enterococci bacteremia among colonized or infected patients, a multiple center, retrospective study in Palestine

Vancomycin-Resistant Enterococcus (VRE) is one of the key antibiotic-resistant pathogens that challenges the health system with its threat to human health. Most VRE infections occur in hospital settings as these pathogens are known to colonize hospital environments and maintain their viability for long periods. Without good infection control measures, these pathogens can spread in the hospital setting and cause hospital-acquired infections including bacteremia. In this study, we report the isolation of VRE from patient samples hospitalized in four Palestinian hospitals. The American Society for Microbiology proceedings were utilized to culture and identify VRE. During the 5-year study period between December 2020 and March 2024, 736 VRE isolates were detected, and 30 (4.76%) patients with bacteremia were reported. Excellent infection control measures including active surveillance swabs, contact precaution and following strict isolation protocols were important to limit the spread of these pathogens, as well as limiting the consumption of antibiotics, especially Vancomycin. In this research article, we discuss the detection of VRE in the different hospitals located in West Bank and East Jerusalem. We also analyze the prevalence of VRE in other body sites including anal surveillance swab, urine, wound and stool cultures that may be associated with developing VRE bacteremia. The cumulative average of VRE causing bacteremia was of urinary origin, followed by wound and stool positive cultures, respectively. Hospital number 2 had the highest risk of developing bacteremia in patients with other VRE positive culture or swab with a percentage of 11.3%.

Etiology, Risk Factors, and Outcomes of Bacteremia in Patients With Hematologic Malignancies and Febrile Neutropenia in Uganda

Background

We determined the etiology, risk factors, and outcomes associated with bacteremia in patients with hematologic malignancies and febrile neutropenia (FN) at the Uganda Cancer Institute (UCI).

Methods

UCI adult and pediatric inpatients with hematologic malignancies and FN were prospectively enrolled and followed up to determine 30-day mortality. Blood drawn from participants with FN was cultured in the BACTEC 9120 blood culture system. Antimicrobial susceptibility testing was performed with the disk diffusion method on identified bacteria. Logistic regression and Cox proportional hazards regression were applied to estimate associations between participant characteristics and FN, bacteremia, and mortality.

Results

Of 495 participants, the majority (n = 306 [62%]) were male. Median age was 23 years (interquartile range, 11-42 years). Of the 132 participants who experienced FN, 43 (33%) had bacteremia. Participants with younger age (odds ratio [OR], 0.98; P = .05), severe neutropenia (OR, 2.9; P = .01), hypotension (OR, 2.46; P = .04), mucositis (OR, 2.77; P = .01), and receipt of chemotherapy (OR, 2.25; P = .03) were more likely to have bacteremia. Fifty (78%) bacteria isolated were gram negative. Escherichia coli (n = 25 [50%]) was predominant. Thirty-seven of 43 (86%) episodes were caused by multidrug-resistant (MDR) bacteria. Thirty-day overall survival for participants with bacteremia was significantly lower than that for participants with no bacteremia (P = .05). MDR bacteremia (hazard ratio, 1.84; P = .05) was associated with increased risk of death.

Conclusions

Bacteremia was frequent in patients with hematologic cancer and FN and was associated with poor survival. MDR bacteria were the main cause of bacteremia and mortality. There is a need for robust infection control and antimicrobial stewardship programs in cancer centers in sub-Saharan Africa.

Global landscape of vancomycin-resistant enterococci in hematopoietic stem-cell transplantation patients: a systematic review and meta-analysis

BACKGROUND

One of the main risks of infection after hematopoietic stem cell transplantation (HSCT) is infection by gram-positive bacteria, including vancomycin-resistant enterococci (VRE). Based on the format of a global review and meta-analysis study, this study aims to investigate the incidence of VRE bloodstream infection (BSI) after HSCT in colonized individuals.

METHODS

The keywords of the systematic search included vancomycin-resistant enterococci and HSCT. These words were searched in Google Scholar, PubMed/Medline, Scopus, and Web of Science databases from January 1, 2000, to March 1, 2024. Studies that reported the prevalence of vancomycin-resistant enterococci in patients undergoing HSCT were included. The random effects model was used for the meta-analyses. Investigations were conducted according to PRISMA guidelines, and the protocol was registered in PROSPERO: CRD42024543491.

RESULTS

Out of 1100 screened papers, 28 were eligible. The random effects model was established to analyze the incidence of VRE BSI after HSCT. The pooled prevalence of co-infection for Allo-HSCT recipients was 3.023 (95% CI, Z-value = -3.5, p-value < 0.0001), and this value for Auto-HSCT recipients was 11.89 (95% CI, Z-value = -2.923, p-value < 0.001). These results showed that the rate of BSI due to vancomycin-resistant enterococcus in Auto-HSCT recipients is higher than Allo-HSCT.

CONCLUSIONS

The prevalence of vancomycin-resistant enterococci in Auto-HSCT recipients is higher than that of Allo-HSCT, possibly due to colonization of the intestines of these people with vancomycin-resistant enterococci before transplantation. VRE Colonization before transplantation increases the likelihood of post-transplant VRE BSI and other bacterial infections, including Gram-negative. The strains should be analyzed by sequencing before and after HSCT for a more detailed investigation.

Carbapenem Versus Non-carbapenem Therapy in Hematology Patients: Extended-Spectrum Beta-Lactamase Positive Enterobacteriaceae Colonization Impact

BACKGROUND

Extended-spectrum beta-lactamase-producing Enterobacteriacea (ESBL-E) infections are a major source of mortality and morbidity in patients with hematologic cancers. One of the most significant risk factors for bacterial illness is prior colonization with resistant germs. Empiric usage of carbapenems is recommended for the treatment of infections in patients with a positive colonization history.

OBJECTIVES

We aimed to determine the outcome of empirical carbapenem (de-escalation) versus non-carbapenem (escalation) therapy in adult hematology patients who have rectal extended-spectrum beta-lactamase positive ESBL-E colonization.

METHODS

Two hundred three rectal swab cultures were collected from 130 patients, admission or during hospitalization between June 2014 and May 2015. Patients were followed till January 2016 for future infections due to ESBL-E. Empirical antibiotic treatment was started according to the patient's medical condition without consideration of previous colonization status. Stable patients received empirical escalation therapy. All-cause and early mortality of infections are analyzed.

RESULTS

Seventy-three (36%) swabs were positive for ESBL-E. Patients with rectal ESBL-E colonization were defined as cases; patients without colonization were defined as controls. Prospective infection due to ESBL-E in the case and control group was 6.8% and 2.3%, respectively. No statistically significant relation was found between colonization and prospective infection due to ESBL-E (p=0.110). There was no all-cause or early mortality in prospective infections with ESBL-E. Among case patients, one patient each died from all-cause mortality in the escalation (n=55) and de-escalation (n=3) group. The all-cause mortality in the antibiotic switch group (n=30) was eight, including five patients in the early mortality group although the bacteriologic agents were susceptible to the given antibiotics.

CONCLUSION

In our institution, rectal colonization with ESBL-E was high, but contracting an infection due to ESBL-E was surprisingly low. Colonization with ESBL-E may not necessarily end with an infection in some situations. In stable patients, disregarding colonization features before empirical therapy did not seem to be inappropriate.

The role of the universal sugar transport system components PtsI (EI) and PtsH (HPr) in Enterococcus faecium

Vancomycin-resistant enterococci (VRE) pose a serious threat to public health because of their limited treatment options. Therefore, there is an increasing need to identify novel targets to develop new drugs. Here, we examined the roles of the universal PTS components, PtsI and PtsH, in Enterococcus faecium to determine their roles in carbon metabolism, biofilm formation, stress response, and the ability to compete in the gastrointestinal tract. Clean deletion of ptsHI resulted in a significant reduction in the ability to import and metabolize simple sugars, attenuated growth rate, reduced biofilm formation, and decreased competitive fitness both in vitro and in vivo. However, no significant difference in stress survival was observed when compared with the wild type. These results suggest that targeting universal or specific PTS may provide a novel treatment strategy by reducing the fitness of E. faecium.

Nutritional Strategies To Improve VRE Control

The rise of Vancomycin-resistant enterococci (VRE) strains among cellular therapy recipients raises concerns due to increased morbidity, mortality, and hospitalization costs, particularly impacting transplanted patients with diminished survival expectations. Recent research linking lactose to Enterococcus growth and graft-versus-host disease (GVHD) emphasizes the need for data on reducing lactose in the diets of VRE-carrying patients, especially in cellular therapy contexts like CAR-T or allogeneic hematopoietic stem cell transplantation. Responding to elevated VRE positivity rates in rectal swabs among patients in our BMT Unit, a unique nutritional strategy was implemented, introducing lactose-free milk and strictly enforcing lactose-free diets. This approach resulted in a significant reduction in VRE carriers, with a 16% positivity rate in the Lactose Group versus 3.6% in the Lactose-Free Group, as of June 2023. These results indicate the potential efficacy of this innovative nutritional strategy in high-risk departments, such as BMT Units and Intensive Care Units, with implications for reducing isolation strategies and inappropriate antibiotic use in cases of VRE colonization.

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.

Impact of vancomycin resistance in Enterococcus faecium bloodstream infection on mortality: A retrospective analysis of nationwide surveillance data

OBJECTIVES

It is unclear whether the poor outcome of patients with severe vancomycin-resistant enterococci (VRE) infection is attributable to vancomycin resistance or to Enterococcus faecium (Efm), which predominates among VRE.

METHODS

Retrospective study of a prospectively identified cohort from nationwide surveillance. A cohort of consecutive, nonduplicate episodes of monomicrobial bloodstream infections (BSIs) caused by Efm in 2016 was selected. The primary outcome was all-cause, 30-day, in-hospital mortality. Inverse probability weighting was applied using the propensity score for vancomycin-resistant Efm (VREfm) BSI.

RESULTS

A total of 241 Efm BSI episodes were included, of which 59 (24.5%) were VREfm. Patients with VREfm BSI were younger but had similar comorbidities to those with vancomycin-sensitive Efm (VSEfm) BSI. Multivariable logistic regression revealed that younger age, previous piperacillin-tazobactam use, and steroid use were significant risk factors for VREfm BSI, but 30-day in-hospital mortality did not differ significantly between groups (35.6% and 23.6% for VREfm and VSEfm, respectively; odds ratio, 1.79; 95% confidence interval, 0.95-3.37; P = 0.101). However, Cox regression with inverse probability weighting revealed that vancomycin resistance was independently associated with an increased risk of mortality (adjusted hazard ratio, 2.18; 95% confidence interval, 1.03-4.62; P = 0.041).

CONCLUSION

In patients with Efm BSI, vancomycin resistance was independently associated with mortality.

Vancomycin-resistant enterococci (VRE) in hospital settings across European borders: a scoping review comparing the epidemiology in the Netherlands and Germany

The rising prevalence of vancomycin-resistant enterococci (VRE) is a matter of concern in hospital settings across Europe without a distinct geographical pattern. In this scoping review, we compared the epidemiology of vancomycin-resistant Enterococcus spp. in hospitals in the Netherlands and Germany, between 1991 and 2022. We searched PubMed and summarized the national antibiotic resistance surveillance data of the two countries. We included 46 studies and summarized national surveillance data from the NethMap in the Netherlands, the National Antimicrobial Resistance Surveillance database in Germany, and the EARS-Net data. In total, 12 studies were conducted in hospitals in the Netherlands, 32 were conducted in German hospitals, and an additional two studies were conducted in a cross-border setting. The most significant difference between the two countries was that studies in Germany showed an increasing trend in the prevalence of VRE in hospitals, and no such trend was observed in studies in the Netherlands. Furthermore, in both Dutch and German hospitals, it has been revealed that the molecular epidemiology of VREfm has shifted from a predominance of vanA towards vanB over the years. According to national surveillance reports, vancomycin resistance in Enterococcus faecium clinical isolates fluctuates below 1% in Dutch hospitals, whereas it follows an increasing trend in German hospitals (above 20%), as supported by individual studies. This review demonstrates that VRE is more frequently encountered in German than in Dutch hospitals and discusses the underlying factors for the difference in VRE occurrence in these two neighboring countries by comparing differences in healthcare systems, infection prevention control (IPC) guidelines, and antibiotic use in the Netherlands and Germany.

Therapeutics for Vancomycin-Resistant Enterococcal Bloodstream Infections

Vancomycin-resistant enterococci (VRE) are common causes of bloodstream infections (BSIs) with high morbidity and mortality rates. They are pathogens of global concern with a limited treatment pipeline. Significant challenges exist in the management of VRE BSI, including drug dosing, the emergence of resistance, and the optimal treatment for persistent bacteremia and infective endocarditis. Therapeutic drug monitoring (TDM) for antimicrobial therapy is evolving for VRE-active agents; however, there are significant gaps in the literature for predicting antimicrobial efficacy for VRE BSIs. To date, TDM has the greatest evidence for predicting drug toxicity for the three main VRE-active antimicrobial agents daptomycin, linezolid, and teicoplanin. This article presents an overview of the treatment options for VRE BSIs, the role of antimicrobial dose optimization through TDM in supporting clinical infection management, and challenges and perspectives for the future.

Gut colonization with vancomicyn-resistant enterococci among patients with hematologic malignancies

BACKGROUND

Vancomycin-resistant enterococci (VRE) are well known agents that colonize the gastrointestinal tract of immunocompromised patients, especially those with hematologic malignancies. The aim of the current study was to determine the incidence of and risk factors for colonization with VRE among patients with hematologic malignancies.

MATERIALS

For a nine-month period, all patients admitted to the Hematology ward at University Hospital in Pleven, Bulgaria who had hematologic malignancy and duration of hospitalization of more than 48 h were screened for colonization with VRE. The data collected from patients and their medical records during the entire hospital stay included: demographic characteristics, clinical information and information about all antimicrobials used. A longitudinal study was used to assesses the risk factors and statistical analysis was performed using SPSS version 27.0.

RESULTS

A total of 119 patients were enrolled in the study. Colonization with VRE was established in 18 of them. One patient carried two species, resulting in a total of 19 VRE: 12 Enterococcus gallinarum, 4 Enterococcus casseliflavus, 2 Enterococcus faecium and 1 Enterococcus faecalis. VanA phenotype, with high-level resistance of vancomycin (MIC ≥ 256 μg/ml) and teicoplanin (MIC = 96 μg/ml), was demonstrated by one E. faecium, which carried vanA. The other E. faecium and E. faecalis expressed low-level resistance to vancomycin (MICs: 8 μg/ml and 12 μg/ml), susceptibility to teicoplanin (MICs = 0.5 μg/ml) and vanB was detected. All E. gallinarum and E. casseliflavus showed low-level resistance to vancomycin and susceptibility to teicoplanin. E. gallinarum strains were positive for vanC1 and E. casseliflavus for vanC2. Only two patients were colonized with vanA or vanB enterococci and the rest 16 were positive for vanC. The univariate analysis revealed that patient's age (70-79 years; p = 0.025) and multiple myeloma (p = 0.001) are risk factors for VRE acquisition among the investigated patients. In addition, the multivariate analysis confirmed that patient's age (70-79 years) is an independent risk factor for VRE colonization.

CONCLUSIONS

Our results showed that 15.1% of patients with hematologic malignancies were colonized with VRE. There was a distinct prevalence of vanC enterococci. Among the analyzed risk factors, advanced age and multiple myeloma contributed to VRE acquisition.

The Dutch Working Party on Antibiotic Policy (SWAB) Recommendations for the Diagnosis and Management of Febrile Neutropenia in Patients with Cancer

INTRODUCTION

This guideline was written by a multidisciplinary committee with mandated members of the Dutch Society for Infectious Diseases, Dutch Society for Hematology, Dutch Society for Medical Oncology, Dutch Association of Hospital Pharmacists, Dutch Society for Medical Microbiology, and Dutch Society for Pediatrics. The guideline is written for adults and pediatric patients.

METHOD

The recommendations are based on the answers to nine questions formulated by the guideline committee. To provide evidence-based recommendations we used all relevant clinical guidelines published since 2010 as a source, supplemented with systematic searches and evaluation of the recent literature (2010-2020) and, where necessary, supplemented by expert-based advice.

RESULTS

For adults the guideline distinguishes between high- and standard-risk neutropenia based on expected duration of neutropenia (> 7 days versus ≤ 7 days). Where possible a distinction has been made between pediatric and adult patients.

CONCLUSION

This guideline was written to aid diagnosis and management of patients with febrile neutropenia due to chemotherapy in the Netherlands. The guideline provides recommendation for children and adults. Adults patient are subdivided as having a standard- or high-risk neutropenic episode based on estimated duration of neutropenia. The most important recommendations are as follows. In adults with high-risk neutropenia (duration of neutropenia > 7 days) and in children with neutropenia, ceftazidime, cefepime, and piperacillin-tazobactam are all first-choice options for empirical antibiotic therapy in case of fever. In adults with standard-risk neutropenia (duration of neutropenia ≤ 7 days) the MASCC score can be used to assess the individual risk of infectious complications. For patients with a low risk of infectious complications (high MASCC score) oral antibiotic therapy in an outpatient setting is recommended. For patients with a high risk of infectious complications (low MASCC score) antibiotic therapy per protocol sepsis of unknown origin is recommended.

Trends of Vancomycin-Resistant Enterococcus Infections in Cancer Patients

Objective Vancomycin-resistant Enterococcus (VRE) is an important cause of infection in immunocompromised populations. In Pakistan, very limited data are available regarding Enterococcus infection and its outcomes. We conducted this study to evaluate the trends including risk factors, treatment options, and outcomes of infections due to vancomycin-resistant enterococci in cancer patients in Pakistan. Methods We conducted a retrospective observational study. We extracted data from medical records of our center over a period of seven years. All admitted cancer patients with any vancomycin-resistant Enterococcus positive culture were included. The following parameters were evaluated: age, gender, type of cancer, febrile neutropenia, prior antibiotics, admission, comorbidities, system-wise infections (including bacteremia, catheter-related infection, pneumonia, urinary tract infections, intra-abdominal infection, bone and joint infections, skin and skin structure infections), intensive care unit admission, and 30-day all-cause mortality. Frequencies of infections, mortality, and drug susceptibility were evaluated over the course of seven years. Results Risk factors for enterococcal infection included prior exposure of piperacillin/tazobactam (n=209, 86.7%), meropenem (n=132, 54.8%), vancomycin (n=126, 52.3%), metronidazole (n=67, 27.8%), prior admission for more than 48 hours (n=198, 82.2%), and comorbidities (n=76, 31.5%), with acute kidney injury being most common (n=72, 95%) followed by diabetes mellitus (n=70, 92.1%). Precursor B cell acute lymphoblastic leukemia (pre-B ALL) was the most common malignancy in which infection occurred (n=54, 38.3%). Among patients who developed infection, 46% (n=111) had febrile neutropenia. Enterococcus species caused infection in 61% (n=147) and Enterococcus faecium in 39% (n=94). Bacteremia occurred in 45.2% (n=109) patients followed by urinary tract and intra-abdominal infection; 45.6% (n=110) patients were admitted to ICU, and 30-day all-cause mortality was 44.8% (n=108). Linezolid sensitivity was 100%. The total number of enterococci infections decreased over seven years. Frequency of E. species infection, bacteremia, intra-abdominal, skin-related infections, and recurrent infection also decreased, but the frequency of E. facium infections, ICU admission, and 30-day all-cause mortality was increased. Conclusion VRE infections have become less frequent but more severe in recent years with increase in mortality. Prior use of antibiotics (including piperacillin/tazobactam, vancomycin, carbapenems, and metronidazole), diagnosis of hematological malignancy, febrile neutropenia, diabetes mellitus, and renal failure are the risk factors for VRE infection. Bacteremia was the most common infection with high mortality rate. All strains remain sensitive to linezolid. Patients with these risk factors should be worked up for VRE and can be treated with linezolid empirically.

Controlling an Unprecedented Outbreak with Vancomycin-Resistant Enterococcus faecium in Germany, October 2015 to November 2019

Hospital outbreaks with vancomycin-resistant enterococci (VRE) pose a serious health threat and a challenge to infection prevention and control (IPC). We herein report on a VRE outbreak of unprecedented extent in Southern Germany (October 2015-November 2019). We used descriptive epidemiology and whole-genome sequencing (WGS) for a detailed outbreak investigation. Of the 2905 cases, 2776 (95.3%) were colonized, whereas from 127 (3.7%), VRE could be isolated from otherwise sterile body fluids or sites unlikely for enterococci colonization. Cases had a median age of 78 years (IQR 68-84) and 1339/2905 (46%) were female. The majority of isolates sequenced belonged to the clonal lineage ST80/CT1013 (212/397, 53%). Nosocomial transmission was observed as well as the constant import of VRE into the hospital. Extensive IPC measures were implemented and terminated the outbreak in late 2019, eventually. Our study shows that the combination of epidemiological and genomic analyses is indispensable for comprehensive outbreak investigations. The adaptation of IPC measures to these findings, their timely implementation, and strict execution also allow containment of large VRE outbreaks in hospital settings.

Intestinal Colonization with Carbapenem-Resistant Enterobacteriaceae in Acute Leukemia Patients: Risk Factors and Molecular Characteristics

Background

Carbapenem-resistant Enterobacteriaceae (CRE) colonization is associated with bacterial translocation, which can result in subsequent endogenous CRE infection. In the present study, we aim to investigate the colonization-related risk factors and molecular epidemiological characteristics of CRE in patients with acute leukemia.

Methods

From January 2021 to December 2021, acute leukemia patients were screened for CRE by fecal/perianal swabs. We identified the species, carbapenemase-encoding genes, and virulence genes of the colonizing strains and performed antimicrobial susceptibility tests and ERIC-PCR typing. Risk factors for CRE colonization were identified by univariate and multivariate analysis.

Results

We collected a total of 21 colonizing strains from 320 patients. All strains were resistant to meropenem. Klebsiella pneumoniae was the most abundant species, and ERIC-PCR typing showed low diversity. Univariate analysis showed that age, cephalosporins, penicillins, tigecyclines, and hematopoietic stem cell transplantation status were risk factors for CRE colonization; simultaneously discovered CRE strains played a dominant role in invasive infection of colonized patients. Logistic multivariate regression analysis showed that age, cephalosporins, and tigecyclines were independent risk factors for CRE intestinal colonization.

Conclusion

CRE colonization can increase the incidence of CRE infection in patients with acute leukemia. Early detection of CRE colonization through CRE screening is an important measure to control the spread of CRE.

Translating Microbiome Research From and To the Clinic

Extensive research has elucidated the influence of the gut microbiota on human health and disease susceptibility and resistance. We review recent clinical and laboratory-based experimental studies associating the gut microbiota with certain human diseases. We also highlight ongoing translational advances that manipulate the gut microbiota to treat human diseases and discuss opportunities and challenges in translating microbiome research from and to the bedside.

Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Multi-body-site colonization screening cultures for predicting multi-drug resistant Gram-negative and Gram-positive bacteremia in hematological patients

BACKGROUND

To investigate the multi-drug resistant bacteria (MDRB) colonization rate in hematological patients hospitalized for any cause using a multi-body-site surveillance approach, and determine the extent to which this screening strategy helped anticipate MDRB bloodstream infections (BSI).

METHODS

Single-center retrospective observational study including 361 admissions documented in 250 adult patients. Surveillance cultures of nasal, pharyngeal, axillary and rectal specimens (the latter two combined) were performed at admission and subsequently on a weekly basis. Blood culture samples were incubated in an automated continuous monitoring blood culturing instrument (BACTEC FX).

RESULTS

In total, 3463 surveillance cultures were performed (pharyngeal, n = 1201; axillary-rectal, n = 1200; nasal, n = 1062). MDRB colonization was documented in 122 out of 361 (33.7%) admissions corresponding to 86 patients (34.4%). A total of 149 MDRB were isolated from one or more body sites, of which most were Gram-negative bacteria, most frequently non-fermenting (n = 83) followed by Enterobacterales (n = 51). BSI were documented in 102 admissions (28%) involving 87 patients. Overall, the rate of BSI caused by MDRB was significantly higher (p = 0.04) in the presence of colonizing MDRB (16 out of 47 admissions in 14 patients) than in its absence (9 out of 55 admissions in 9 patients). Colonization by any MDRB was independently associated with increased risk of MDRB-BSI (HR, 3.70; 95% CI, 1.38-9.90; p = 0.009).

CONCLUSION

MDRB colonization is a frequent event in hematological patients hospitalized for any reason and is associated with an increased risk of MDRB BSI. The data lend support to the use of MDRB colonization surveillance cultures for predicting the occurrence of MDRB BSI in this cohort.

Evaluating Initial Empiric Therapy for Neutropenic Fever in Vancomycin-Resistant Enterococcus-Colonized Patients

Objectives

Vancomycin-resistant enterococcus infections impact mortality in oncology patients. Given the low rate of vancomycin-resistant enterococcus bacteremia, low virulence of vancomycin-resistant enterococcus, and advent of rapid diagnostic systems, vancomycin-resistant enterococcus-directed empiric therapy in vancomycin-resistant enterococcus-colonized patients with neutropenic fever may be unnecessary, promoting increased antimicrobial resistance, drug-related toxicity, and cost.

Methods

Vancomycin-resistant enterococcus-colonized adults admitted for hematopoietic stem cell transplantation or induction therapy for acute leukemia/myeloid sarcoma with neutropenic fever were stratified by vancomycin-resistant enterococcus bacteremia development and empiric vancomycin-resistant enterococcus-directed antimicrobial strategy for first neutropenic fever (Empiric Therapy vs. non-Empiric Therapy). Primary endpoints included vancomycin-resistant enterococcus-related, in-hospital, and 100-day mortality rates. Secondary outcomes included vancomycin-resistant enterococcus bacteremia incidence for first neutropenic fever and the entire hospitalization, length of stay, Clostridioides difficile infection rate, and duration and cost of vancomycin-resistant enterococcus-directed therapy.

Results

During first neutropenic fever, 3 of 70 eligible patients (4%) developed vancomycin-resistant enterococcus bacteremia. Although all 3 (100%) were non-Empiric Therapy, no mortality (0%) occurred. Of 67 patients not developing vancomycin-resistant enterococcus bacteremia, 42 (63%) received Empiric Therapy and 25 (37%) non-Empiric Therapy. Empiric Therapy had significantly greater median duration (3 days vs. 0 days; P<.001) and cost ($1604 vs. $0; P<.001) of vancomycin-resistant enterococcus-directed therapy but demonstrated no significant differences in clinical outcomes.

Conclusion

Available data suggest Empiric Therapy may offer no clinical benefit to this population, regardless of whether vancomycin-resistant enterococcus is identified in blood culture or no pathogen is found. Such an approach may only expose the majority of patients to unnecessary vancomycin-resistant enterococcus-directed therapy and drug-related toxicities while increasing institutional drug and monitoring costs. Even in the few patients developing vancomycin-resistant enterococcus bacteremia, waiting until the organism is identified in culture to start directed therapy likely makes no difference in mortality. This lack of benefit warrants consideration to potentially omit empiric vancomycin-resistant enterococcus-directed therapy in first neutropenic fever in many of these patients.

Antimicrobial Stewardship and the Infection Control Practitioner: A Natural Alliance

Antibiotic overuse and misuse has contributed to rising rates of multidrug-resistant organisms and Clostridioides difficile. Decreasing antibiotic misuse has become a national public health priority. This review outlines the goals of antimicrobial stewardship, essential members of the program, implementation strategies, approaches to measuring the program's impact, and steps needed to build a program. Highlighted is the alliance between antimicrobial stewardship programs and infection prevention programs in their efforts to improve antibiotic use, improve diagnostic stewardship for C difficile and asymptomatic bacteriuria, and decrease health care-associated infections and the spread of multidrug-resistant organisms.

Critical Care of Hematopoietic Stem Cell Transplant Patients

Life-threatening complications are frequent after hematopoietic stem cell transplant (HSCT), and optimum critical care is essential to ensuring good outcomes. The immunologic consequences of HSCT result in a markedly different host response to critical illness. Infection is the most common cause of critical illness but noninfectious complications are frequent. Respiratory failure or sepsis are the typical presentations but the sequelae of HSCT can affect nearly any organ system. Pattern recognition can facilitate anticipation and early intervention in post-HSCT critical illness. HSCT critical care is a multidisciplinary endeavor. Continued investigation and focus on process improvement will continue to improve outcomes.

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

BACKGROUND

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

PATIENTS-METHODS

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

RESULTS

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

CONCLUSION

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

Impact of a Clostridioides Difficile Testing Computerized Clinical Decision Support Tool on an Adult Stem Cell Transplantation and Hematologic Malignancies Unit

Clostridioides difficile infection rates are higher in hospitalized hematopoietic stem cell transplantation (HSCT) recipients and patients with hematologic malignancy (HM) compared with the general population. This is related both to extensive exposure to antibiotics as well as to frequent and often prolonged hospitalization. In this population, with numerous potential causes of diarrhea, a subset of C difficile detected is presumed to represent colonization rather than clinical infection. The use of decision support tools to guide ordering in hospitalized patients has been reported to decrease both C difficile testing and detection rates. Following implementation of a computerized decision support tool on our HSCT/HM unit, we observed a >2-fold decrease in C difficile testing volume and National Healthcare Safety Network-defined laboratory identifications of C difficile. Furthermore, the rate of oral vancomycin use, as well as the incidence of vancomycin-resistant enterococci colonization and bloodstream infection, decreased in the postintervention period.

Management of fever and neutropenia in the adult patient with acute myeloid leukemia

INTRODUCTION

Febrile neutropenia represents one of the most common treatment-associated complications in the management of acute myeloid leukemia (AML) and is considered an oncologic emergency. Rapid and detailed workup as well as the initiation of empiric broad-spectrum antibiotic therapy are critical to avoid sepsis and to reduce mortality. Although a definitive source of infection is frequently not identified, the severely immunosuppressed status of the AML patient undergoing cytotoxic therapy results in a high risk for a wide array of bacterial, fungal, and viral etiologies.

AREAS COVERED

The authors herein review the diagnostic and therapeutic approach to the neutropenic leukemia patient based on the current knowledge. Special consideration is given to the rapidly changing therapeutic landscape in AML, creating new challenges in the management of infectious complications.

EXPERT OPINION

Multidrug-resistant organisms pose a major challenge in the management of neutropenic fever patients with hematologic malignancies - including AML. Future directions to improve outcomes demand innovative treatment approaches as well as advances in biomarker research to facilitate diagnosis and disease monitoring. Recent achievements in AML-targeted therapy led to an increased incidence of differentiation syndrome, a potentially life-threatening side effect that frequently resembles clinical infection and requires prompt recognition and aggressive intervention.

Does oral doxycycline treatment affect eradication of urine vancomycin-resistant Enterococcus? A tertiary hospital study

Background

Vancomycin-resistant Enterococcus (VRE) has become more common in nosocomial infections, especially in urine samples. However, until now, no treatment regimen has been proven to effectively eradicate urine VRE colonization. Therefore, to evaluate the efficacy of doxycycline in eradicating urine VRE and shortening VRE isolation period, we compared VRE colony detection period between doxycycline-treated and untreated patients.

Methods

A retrospective cohort study of 83 patients with VRE colonization in urine cultures was conducted at a tertiary academic hospital from January 2011 to February 2018. Kaplan-Meier survival analysis was used to evaluate eradication rates in the treatment and non-treatment groups. Factors affecting urine VRE colonization persistence were analyzed by multiple logistic regression analysis.

Results

The overall rate of VRE eradication during the entire hospital stay was higher in the doxycycline treatment group (90.5%) than in the non-treatment group (58.1%, p=0.014). Survival analysis showed that the 5-, 10-, and 20-day cumulative eradication rates were 78.3%, 100%, and 100% in the doxycycline treatment group, and 18.5%, 45.7%, and 67.8% in the non-treatment group, respectively, thereby indicating that eradication rates were higher in the doxycycline treatment group than in the non-treatment group (p<0.001). Only doxycycline treatment was shown to affect urine VRE colonization persistence in multivariate logistic regression analysis.

Conclusion

Doxycycline treatment enhanced the eradication rate of urine VRE colonization and appeared to be useful in shortening VRE isolation period.

ICU Complications of Hematopoietic Stem Cell Transplant, Including Graft vs Host Disease

Hematopoietic stem cell transplant (HSCT) is an essential treatment modality for many malignant and non-malignant hematologic diseases. Advances in HSCT techniques have dramatically decreased peri-transplant morbidity and mortality, but it remains a high-risk procedure, and a significant number of patients will require critical care during the transplant process. Complications of HSCT are both infectious and non-infectious, and the intensivist must be familiar with common infections, the management of neutropenic sepsis and septic shock, the management of respiratory failure in the immunocompromised host, and a plethora of HSCT-specific complications. Survival from critical illness after HSCT is improving, but the mortality rate remains unacceptably high. Continued research and optimization of critical care provision in this population should continue to improve outcomes.

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.

Antimicrobial Stewardship in Hematological Patients at the intensive care unit: a global cross-sectional survey from the Nine-i Investigators Network

A global cross-sectional survey was performed to gather data on the current treatment of infections caused by multidrug-resistant (MDR) bacteria among hematological patients admitted to ICUs worldwide. The survey was performed in April 2019 using an electronic platform (SurveyMonkey®) being distributed among 83 physicians and completed by 48 (57.8%) responders. ESBL Enterobacteriaceae, carbapenem-resistant K. pneumoniae and carbapenem-resistant P. aeruginosa were the main concerns. Previous MDR infection (34% of responders), MDR colonization (20%) and previous antibiotic exposure within the last 3 months (20.5%) were considered the most relevant risk factors of bloodstream infection (BSI) due to MDR bacteria. In 48.8% of the ICUs, there was no antimicrobial stewardship (AMS) team focused on hematological patients. Updates on local epidemiology of MDR pathogens were provided in 98% of the centers, using phone or verbal communications (56.1% and 53.7%, respectively). In presence of febrile neutropenia, initial therapy consisted of anti-Gram-negative plus anti-Gram-positive antibiotics for 41% of participants. Antibiotic de-escalation and/or discontinuation of therapy were considered as a promising strategy for the prevention of MDR development (32.4%). Factors associated with antibiotic de-escalation were clinical improvement (43.6%) and neutrophil count recovery (12.8%). Infectious Disease consultation and AMS interventions were not determining factors for de-escalation decisions (more than 50% of responders). Infection control and educational programs were valued as necessary measures for implementation by ICU practitioners. These findings should guide future efforts on collaborative team working, improving compliance with adequate treatment protocols, implementing antimicrobial stewardship programs in critically ill hematological patients, and educational activities.

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.

Pathogenicity of Enterococci

Enterococci are unusually well adapted for survival and persistence in a variety of adverse environments, including on inanimate surfaces in the hospital environment and at sites of infection. This intrinsic ruggedness undoubtedly played a role in providing opportunities for enterococci to interact with other overtly drug-resistant microbes and acquire additional resistances on mobile elements. The rapid rise of antimicrobial resistance among hospital-adapted enterococci has rendered hospital-acquired infections a leading therapeutic challenge. With about a quarter of a genome of additional DNA conveyed by mobile elements, there are undoubtedly many more properties that have been acquired that help enterococci persist and spread in the hospital setting and cause diseases that have yet to be defined. Much remains to be learned about these ancient and rugged microbes, particularly in the area of pathogenic mechanisms involved with human diseases.

The direct and indirect effects of vancomycin-resistant enterococci colonization in liver transplant candidates and recipients

Introduction: Vancomycin-resistant enterococci (VRE) colonization and subsequent infection results in increased morbidity, mortality and use of health-care resources. The burden of VRE colonization in liver transplant candidates and recipients is significant. VRE colonization is a marker of gut dysbiosis and its impact on the microbiota-liver axis, may negatively affect graft function and result in negative outcomes pre- and post-transplantation. Areas covered: In this article we describe the epidemiology of VRE colonization, risk factors for VRE infection, health-care costs associated with VRE, with a focus on the impact of VRE colonization on liver transplant recipients' fecal microbiota, the therapeutic strategies for VRE decolonization and proposed pathophysiologic mechanisms of VRE colonization in liver transplant recipients. Expert opinion: VRE colonization results in a significant loss of bacterial microbiome diversity. This may have metabolic consequences, with low production of short-chain fatty acids which may, in turn, result in immune dysregulation. As antibiotics have failed to decolonize the gut, alternative strategies such as fecal microbiota transplantation (FMT), stimulation of intestinal antimicrobial peptides and phage therapy warrants future studies.

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.

A retrospective cohort study of antibiotic exposure and vancomycin-resistant Enterococcus recolonization

OBJECTIVE

In the National Institutes of Health (NIH) Clinical Center, patients colonized or infected with vancomycin-resistant Enterococcus (VRE) are placed in contact isolation until they are deemed "decolonized," defined as having 3 consecutive perirectal swabs negative for VRE. Some decolonized patients later develop recurrent growth of VRE from surveillance or clinical cultures (ie, "recolonized"), although that finding may represent recrudescence or new acquisition of VRE. We describe the dynamics of VRE colonization and infection and their relationship to receipt of antibiotics.

METHODS

In this retrospective cohort study of patients at the National Institutes of Health Clinical Center, baseline characteristics were collected via chart review. Antibiotic exposure and hospital days were calculated as proportions of VRE decolonized days. Using survival analysis, we assessed the relationship between antibiotic exposure and time to VRE recolonization in a subcohort analysis of 72 decolonized patients.

RESULTS

In total, 350 patients were either colonized or infected with VRE. Among polymerase chain reaction (PCR)-positive, culture (Cx)-negative (PCR+/Cx-) patients, PCR had a 39% positive predictive value for colonization. Colonization with VRE was significantly associated with VRE infection. Among 72 patients who met decolonization criteria, 21 (29%) subsequently became recolonized. VRE recolonization was 4.3 (P = .001) and 2.0 (P = .22) times higher in patients with proportions of antibiotic days and antianaerobic antibiotic days above the median, respectively.

CONCLUSION

Colonization is associated with clinical VRE infection and increased mortality. Despite negative perirectal cultures, re-exposure to antibiotics increases the risk of VRE recolonization.

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.

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.

The Hematopoietic Cell Transplant Pharmacist: Roles, Responsibilities, and Recommendations from the ASBMT Pharmacy Special Interest Group

Pharmacists are increasingly recognized as an essential member of the multidisciplinary team for hematopoietic cell transplant (HCT) patients. However, until recently, their educational background, required training, and potential roles have not been well described. Therefore, the purpose of this manuscript is to provide supporting evidence for the HCT Clinical Pharmacist Role Description, which has been endorsed by several organizations including the American Society for Blood and Marrow Transplantation. This document provides justification for the various roles pharmacists fulfill with respect to medication management, transitions of care, patient and provider education, policy development, quality improvement, and research. Furthermore, evidence supporting the value, financially and otherwise, HCT pharmacists provide is reviewed. Pharmacists in the HCT setting are encouraged to report on novel practice models and potential impact of their services to increase awareness and utilization of HCT pharmacists.

Clinical impact of colonization with multidrug-resistant organisms on outcome after allogeneic stem cell transplantation in patients with acute myeloid leukemia

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment option for patients with acute myeloid leukemia (AML). During transplantation, patients undergo a period of severe neutropenia, which puts them at high risk for infectious complications. However, the impact of patient colonization with multidrug-resistant organisms (MDRO) on overall survival remains unclear.

METHODS

In this retrospective, single-center study, the authors analyzed data from 264 patients with AML who underwent a first allo-HSCT between January 2006 and March 2016 at their institution. Primary endpoints were overall survival and nonrelapse-related mortality.

RESULTS

One hundred forty-two of 264 patients (53.8%) were colonized by at least 1 MDRO, mainly with vancomycin-resistant Enterococcus faecalis/faecium (n = 122). The characteristics of colonized patients did not differ from those of MDRO-negative patients with respect to median age (53.5 vs 53 years), cytogenetic risk according to European LeukemiaNet criteria, remission status before allo-HSCT (first or second complete remission: 55.7% vs 60.7%, respectively; active disease: 44.4% vs 39.3%, respectively), donor type, or hematopoietic cell transplantation-comorbidity index (HCT-CI). Compared with noncolonized patients, MDRO-positive patients had an inferior probability of survival at 5 years (43.3% vs 65.5%; P = .002), primarily because of a higher cumulative incidence of nonrelapse-related mortality (33.9% vs 9.4%; P < .001). Death caused by infections occurred in 15.5% of colonized patients versus 4.9% of noncolonized patients. There was no difference in the cumulative incidence of relapse in MDRO-positive versus MDRO-negative patients (33.8% vs 42.1%, respectively; P = .798).

CONCLUSIONS

The current data emphasize the importance of regular MDRO screenings and prompt further investigations into the impact of colonization with MDRO on the immune system after allo-HSCT. Cancer 2018;124:286-96. © 2017 American Cancer Society.

The intestinal microbiota: Antibiotics, colonization resistance, and enteric pathogens

The human gastrointestinal tract hosts a diverse network of microorganisms, collectively known as the microbiota that plays an important role in health and disease. For instance, the intestinal microbiota can prevent invading microbes from colonizing the gastrointestinal tract, a phenomenon known as colonization resistance. Perturbations to the microbiota, such as antibiotic administration, can alter microbial composition and result in the loss of colonization resistance. Consequently, the host may be rendered susceptible to colonization by a pathogen. This is a particularly relevant concern in the hospital setting, where antibiotic use and antibiotic-resistant pathogen exposure are more frequent. Many nosocomial infections arise from gastrointestinal colonization. Due to their resistance to antibiotics, treatment is often very challenging. However, recent studies have demonstrated that manipulating the commensal microbiota can prevent and treat various infections in the intestine. In this review, we discuss the members of the microbiota, as well as the mechanisms, that govern colonization resistance against specific pathogens. We also review the effects of antibiotics on the microbiota, as well as the unique epidemiology of immunocompromised patients that renders them a particularly high-risk population to intestinal nosocomial infections.

Bloodstream infections in acute myeloid leukemia patients treated according to the Finnish Leukemia Group AML-2003 protocol - a prospective nationwide study

BACKGROUND

Infections greatly influence the outcome of acute myeloid leukemia (AML) patients receiving intensive treatment. The aim of this study was to establish the incidence, microbial etiology, risk factors and prognosis of bloodstream infections (BSIs) in patients with AML and compare the results with the previous treatment protocol (AML-92).

METHODS

Registery data were gathered prospectively from 357 patients aged 16-65 years recruited on the AML-2003 treatment protocol between November 2003 and November 2011 during different treatment cycles.

RESULTS

Blood culture data were available on 977 treatment episodes, in which there were 503 BSIs (51%). The overall incidence rate (IR) for BSIs (per 1000 hospital days) was 16.7. Twenty patients (5.6%) died due to an infection and 16 of them (80%) had a BSI. The most commonly detected microbes (polymicrobial episodes included) in blood cultures were coagulase-negative staphylococci (CoNS, 24.7%), viridans group streptococci (VGS, 19.1%), enterococci (13.9%) and Enterobacteriacae group (25.9%). The etiology of BSIs varied greatly from treatment cycle to cycle.

CONCLUSIONS

Enterococcal BSIs have increased compared to our previous treatment protocol, and they represent significant pathogens in blood cultures. Infection-related mortality has decreased despite the increase in the IR of BSIs. Enterococci seem to be an increasingly prominent pathogen underlying BSIs in the AML patients, especially during induction therapy (20%).

Microbiota-Based Therapies for Clostridium difficile and Antibiotic-Resistant Enteric Infections

Bacterial pathogens are increasingly antibiotic resistant, and development of clinically effective antibiotics is lagging. Curing infections increasingly requires antimicrobials that are broader spectrum, more toxic, and more expensive, and mortality attributable to antibiotic-resistant pathogens is rising. The commensal microbiota, comprising microbes that colonize the mammalian gastrointestinal tract, can provide high levels of resistance to infection, and the contributions of specific bacterial species to resistance are being discovered and characterized. Microbiota-mediated mechanisms of colonization resistance and pathogen clearance include bactericidal activity, nutrient depletion, immune activation, and manipulation of the gut's chemical environment. Current research is focusing on development of microbiota-based therapies to reduce intestinal colonization with antibiotic-resistant pathogens, with the goal of reducing pathogen transmission and systemic dissemination.

Clinical Impact of Colonization with Multidrug-Resistant Organisms on Outcome after Autologous Stem Cell Transplantation: A Retrospective Single-Center Study

A significant increase in infections caused by multidrug-resistant organisms (MDRO) has been observed in recent years, resulting in an increase of mortality in all fields of health care. Hematological patients are particularly affected by MDRO infections because of disease- and therapy-related immunosuppression. To determine the impact of colonization with MDRO on overall survival, we retrospectively analyzed data from patients undergoing autologous hematopoietic stem cell transplantation at our institution. In total, 184 patients were identified, mainly patients with lymphomas (n = 98, 53.3%), multiple myelomas (n = 80, 43.5%), germ cell cancers (n = 5, 2.7%), or acute myeloid leukemia (n = 1, .5%). Forty patients (21.7%) tested positive for MDRO colonization. At a median follow-up time of 21.5 months, the main causes of death were infection in colonized and disease progression in noncolonized patients. Nonrelapse mortality (NRM) was higher in patients who tested positive for MDRO than in the noncolonized group (25.4% versus 3%, P < .001). Interestingly, NRM in neutropenia after autologous transplantation did not differ between colonized and noncolonized patients. Colonized patients, however, had inferior overall survival after autologous transplantation in univariate (61.7% versus 73.3%, P = .005) as well as in multivariate analysis (hazard ratio, 2.463; 95% confidence interval, 1.311 to 4.626; P = .005). We conclude that the period after discharge from hospital after autologous transplantation seems critical and patients with MDRO colonization should be observed closely for infections in the post-transplantation period in outpatient care.

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

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

Emergence of Vancomycin-resistant Enterococci at a Teaching Hospital, Saudi Arabia

Background:

Vancomycin-resistant enterococci (VRE) are a major and emerging hospital-acquired pathogen associated with high mortality, particularly among the critically ill and Intensive Care Units (ICUs) patients. This study aimed to determine the prevalence and demographic and clinical characteristics of VRE among patients admitted to a university hospital in Riyadh, Saudi Arabia.

Methods:

A study was conducted during the period from September 2014 to November 2015 at King Khalid University Hospital, a tertiary care hospital in Riyadh, Saudi Arabia, including in-patients with VRE infection. Data were collected using laboratory results and the medical records of admitted patients and were analyzed using SPSS version 19.0 statistical software.

Results:

In a one-year period, 231 enterococci were isolated from blood, urine, exudates, sputum, stool, and body fluid. There were 191 (82.7%) vancomycin-sensitive enterococci (VSE) and 40 (17.3%) isolates were VRE. The Enterococcus species included E. faecalis 168 (72.7%), E. faecium, 53 (22.8%) E. gallinarum 5 (2.2%), and E. avium 5 (2.2%). VRE were more significant from blood specimens (P < 0.0001) while VSE were significantly more predominant from urine specimens (P < 0.0001). VRE were more commonly isolated from patients in ICUs and oncology unit (P = 0.0151 and P < 0.001, respectively) while VSE were more predominant in the medical and surgical areas (P = 0.0178 and P = 0.0178, respectively).

Conclusions:

This study highlights the high prevalence of VRE in the hospital and the association of enterococcal infections with high-risk areas and oncology units, which warrant more studies looking for better management of these infections.