Pre- and post-engraftment bloodstream infection rates and associated mortality in allogeneic hematopoietic stem cell transplant recipients

Epidemiology of bloodstream infections and the impact of antimicrobial resistance in pediatric hematopoietic cell transplant

Bloodstream infections (BSI) pose a substantial threat to the well-being and survival of patients undergoing hematopoietic stem cell transplantation (HSCT). Risk factors for these infections vary across the different post-HSCT phases. In the pre-engraftment period, patients are particularly susceptible to infection due to prolonged neutropenia, mucosal damage, and extensive use of central venous line (CVL). In the post-engraftment phase, the emergence of graft versus host diseases further compounds the risk. The epidemiology of these infections has undergone notable changes over the years due to multifactorial reasons, including the evolution of protocols that intensify immunosuppression. In this context, the emergence of multi-drug resistance (MDR) microorganisms can be a challenge due to the elevated risk of mortality in these vulnerable patients. Unfortunately, there is a lack of comprehensive data on this topic, particularly in pediatrics. This article aims to provide a summary of the epidemiology of BSI in the different post-transplant phases and the impact of MDR pathogens. Having knowledge about the local epidemiology of BSI can be instrumental in tailoring targeted therapies, leading to improved survival rates in HSCT recipients.

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

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

High frequency of viridians group streptococci bacteremia in pediatric neuroblastoma high-risk patients during induction chemotherapy

Existing literature on febrile neutropenia (FN) has categorized patients with acute leukemia or those undergoing allogeneic stem cell transplantation (SCT) as being high risk for severe infection, bacteremia, and poor outcomes. Comprehensive studies of infection risk in pediatric high-risk neuroblastoma (NB-HR) during induction chemotherapy are limited, and mostly merged within the solid tumor (ST) group. Therefore, it is unclear whether infectious complications and outcomes for NB-HR are the same as in other ST groups. We conducted a retrospective medical record review of pediatric FN patients in a single center from March 2009 to December 2016. FN episodes were categorized into five groups based on underlying diagnosis (acute myelogenous leukemia (AML), acute lymphocytic leukemia (ALL), NB-HR during induction chemotherapy, other solid tumors, and SCT). Comparative analyses of infectious complications between patients with NB-HR and those with other types of cancer diagnoses were performed. A total of 667 FN episodes (FNEs) were identified in 230 patients. FNEs occurred in 82 episodes with NB-HR. Bloodstream infection (BSI) occurred in 145 (21.7%) of total FN episodes. The most isolated organisms were the viridians group streptococci (VGS) (25%). NB-HR patients have higher rates of VGS bacteremia (OR 0.15, 95% [CI 0.04, 0.56]) and are more likely to be admitted to the Pediatric Intensive Care Unit (PICU) compared to patients with other solid tumors (OR 0.36, 95% [CI 0.15, 0.84]). Interestingly, there is no difference in VGS rates between patients with NB-HR and those with AML despite the fact that NB-HR patients do not receive a cytosine arabinoside (AraC)-based regimen. This large neuroblastoma cohort showed that patients with NB-HR during induction chemotherapy are at higher risk for VGS bacteremia and PICU admissions compared with patients with other solid tumors. Further prospective studies are needed to investigate infection-related complications in this high-risk group and to improve morbidity and mortality.

Klebsiella quasipneumoniae in intestine damages bile acid metabolism in hematopoietic stem cell transplantation patients with bloodstream infection

BACKGROUND

Bloodstream infection (BSI) is a serious hematopoietic stem cell transplantation (HSCT) complication. The intestinal microbiome regulates host metabolism and maintains intestinal homeostasis. Thus, the impact of microbiome on HSCT patients with BSI is essential.

METHODS

Stool and serum specimens of HSCT patients were prospectively collected from the pretransplant conditioning period till 4 months after transplantation. Specimens of 16 patients without BSI and 21 patients before BSI onset were screened for omics study using 16S rRNA gene sequencing and untargeted metabolomics. The predictive infection model was constructed using LASSO and the logistic regression algorithm. The correlation and influence of microbiome and metabolism were examined in mouse and Caco-2 cell monolayer models.

RESULTS

The microbial diversity and abundance of Lactobacillaceae were remarkably reduced, but the abundance of Enterobacteriaceae (especially Klebsiella quasipneumoniae) was significantly increased in the BSI group before onset, compared with the non-BSI group. The family score of microbiome features (Enterobacteriaceae and Butyricicoccaceae) could highly predict BSI (AUC = 0.879). The serum metabolomic analysis showed that 16 differential metabolites were mainly enriched in the primary bile acid biosynthesis pathway, and the level of chenodeoxycholic acid (CDCA) was positively correlated with the abundance of K. quasipneumoniae (R = 0.406, P = 0.006). The results of mouse experiments confirmed that three serum primary bile acids levels (cholic acid, isoCDCA and ursocholic acid), the mRNA expression levels of bile acid farnesol X receptor gene and apical sodium-dependent bile acid transporter gene in K. quasipneumoniae colonized mice were significantly higher than those in non-colonized mice. The intestinal villus height, crypt depth, and the mRNA expression level of tight junction protein claudin-1 gene in K. quasipneumoniae intestinal colonized mice were significantly lower than those in non-colonized mice. In vitro, K. quasipneumoniae increased the clearance of FITC-dextran by Caco-2 cell monolayer.

CONCLUSIONS

This study demonstrated that the intestinal opportunistic pathogen, K. quasipneumoniae, was increased in HSCT patients before BSI onset, causing increased serum primary bile acids. The colonization of K. quasipneumoniae in mice intestines could lead to mucosal integrity damage. The intestinal microbiome features of HSCT patients were highly predictive of BSI and could be further used as potential biomarkers.

Clinical impact and early prediction of carbapenem-resistant Pseudomonas aeruginosa bacteraemia in allogeneic hematopoietic stem cell transplantation recipients

OBJECTIVE

Although antipseudomonal agents are administered in high-risk patients, no reports have focused on the risk of carbapenem-resistant (CR) Pseudomonas aeruginosa bacteraemia in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients.

METHODS

We retrospectively studied a cohort of adult allo-HSCT recipients with P. aeruginosa bacteraemia, focusing on a comparison between carbapenem-sensitive (CS) and CR P. aeruginosa after initiating conditioning chemotherapy at our institute between January 2005 and December 2020. The incidence, all-cause 30-d mortality of P. aeruginosa bacteraemia, and risk factors for carbapenem resistance among patients with P. aeruginosa bacteraemia in allo-HSCT recipients were evaluated.

RESULTS

Forty-eight patients with P. aeruginosa bacteraemia were included, with an incidence of 3.84/100 recipients (CS = 1.92 vs. CR = 1.92). The all-cause 30-d mortality was significantly higher in CR P. aeruginosa bacteraemia (CS = 4.2% vs. CR = 39.1%; P = 0.003). The factor significantly associated with CR P. aeruginosa bacteraemia was carbapenem use for at least 3 d within 30 d before the onset of bacteraemia (odds ratio = 8.92; 95% confidence interval: 1.35-58.90). Inappropriate antimicrobial selection was significantly more frequent in CR P. aeruginosa bacteraemia (CS = 0% vs. CR = 29.2%; P ˂ 0.009).

CONCLUSION

Empirical combination therapy with reference to antimicrobial susceptibility profiles in each institution should be considered when CR P. aeruginosa bacteraemia is suspected in allo-HSCT recipients based on the risk of carbapenem exposure.

Medical emergencies in pediatric blood & marrow transplant and cellular therapies

Hematopoietic stem cell transplant (HCT) is used for many pediatric malignant and non-malignant diseases. However, these patients are at a high risk for emergencies post-transplant, related to prior comorbidities and treatments for the underlying disease, high dose chemotherapy regimen related toxicities, prolonged myelosuppression, and opportunistic infections due to their immunocompromised state. Emergencies can be during preparative regimen and hematopoietic progenitor cell (HPC) infusion, acute post-transplant (pre-engraftment) and late during post engraftment. Infectious complications are the most common cause of morbidity and mortality in the peri-transplant period. Sinusoidal obstructive syndrome is another life-threatening emergency seen in children undergoing HCT, especially in infants. Timely recognition and administration of defibrotide with/without steroids is key to the management of this complication. Another complication seen is transplant associated thrombotic microangiopathy. It can cause multiorgan failure if left untreated and demands urgent identification and management with complement blockade agents such as eculizumab. Cytokine release syndrome and cytokine storm is an important life-threatening complication seen after cellular therapy, and needs emergent intervention with ICU supportive care and tocilizumab. Other complications in acute period include but are not limited to: seizures from busulfan or other chemotherapy agents, PRES (posterior reversible encephalopathy syndrome), diffuse alveolar hemorrhage, idiopathic pulmonary syndrome and allergic reaction to infusion of stem cells. Acute graft versus host disease (GvHD) is a major toxicity of allogeneic HCT, especially with reduced intensity conditioning, that can affect the skin, liver, upper and lower gastrointestinal tract. There has been major development in new biomarkers for early identification and grading of GvHD, which enables application of treatment modalities such as post-transplant cyclophosphamide and JAK/STAT inhibitors to prevent and treat GvHD. Myelosuppression secondary to the chemotherapy increases risk for engraftment syndrome as well as coagulopathies, thus increasing the risk for clotting and bleeding in the pediatric population. The purpose of this article is to review recent literature in these complications seen with pediatric hematopoietic cell transplant (HCT) and cellular therapies and provide a comprehensive summary of the major emergencies seen with HCT.

Bacterial Bloodstream Infections in Patients Undergoing Allogeneic Hematopoietic Cell Transplantation With Post-Transplantation Cyclophosphamide

This study investigates the incidence and predictors for bacterial bloodstream infection (BSI) in 330 adults undergoing allo-HCT, and explores the effect of post-transplantation cyclophosphamide (PTCY) on the probability of presenting this complication. All patients received levofloxacin during the aplastic phase. Only the first episode of BSI was counted as an event. Patients were classified into 2 groups: PTCY-based (n = 200) versus other prophylaxis (n = 130). One hundred twenty-four patients were diagnosed with a first episode of BSI, most of them during the first 30 days (70.2%). Proportions of BSIs caused by Gram-positive bacteria were comparable to those caused by Gram-negative bacteria (48.3% versus 45.9%). The cumulative incidence of BSI was higher in patients receiving PTCY than in those receiving other prophylaxis (days 30 and 100: 35.0% and 37.0% versus 13.1% and 18.5%, P < .001). At day 30, the likelihood of BSI was 2.41 (P = .012) times higher in the PTCY group than in the non-PTCY group. The 30-day mortality rate in all patients with BSI was 8.0%, lower (P = .002) in the PTCY group (2.3%) than in the non-PTCY group (21.6%). Finally, the overall survival of patients receiving PTCY and diagnosed with BSI was similar to that of patients without presenting this complication. © 2023 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Clinical Characteristics, Microbiology, and Risk Factors for Mortality of Pre-Engraftment and Post-Engraftment Bloodstream Infection in Hematopoietic Stem Cell Transplantation Recipients

BACKGROUND

Bloodstream infection (BSI) is a common and serious complication that may lead to high mortality during the different phases after hematopoietic stem cell transplant (HSCT). We investigated BSI in patients undergoing HSCT to provide an appropriate clinical anti-infection experience and improve the prognosis of recipients with BSI after HSCT.

METHODS

A total of 105 patients with BSI after HSCT at our center from January 2015 to June 2020 were included in this retrospective study. We analyzed the clinical and microbiological data, and the risk factors for mortality at 3 months after BSI.

RESULTS

Of the 1141 HSCT recipients, 105 (9.2%) patients presented with 122 episodes of BSI, of which we isolated 85 (65.9%) gram-negative bacteria, 32 (24.8%) gram-positive bacteria and 12 (9.3%) fungi. Multidrug-resistant bacteria (MDR) were more than 70% of all pathogens and carbapenem-resistant organisms (CRO) were 25.6%. There were 55 episodes of BSI in the pre-engraftment phase and 67 episodes in the post-engraftment phase. The mortality of post-engraftment BSI was significantly higher than that of pre-engraftment (56.7% vs 32.7%, p = 0.005). Through multivariate analysis, the independent risk factors for all-cause mortality at 3 months after BSI were higher levels of procalcitonin (PCT), failure to cover appropriate antibiotics timely, and CRO BSI in pre-engraftment period or multidrug-resistant gram-negative bacteria (MDRGNB) BSI in post-engraftment period.

CONCLUSION

Although the incidence of BSI was lower after HSCT, MDR-dominated BSI had a high mortality rate. Rapid identification of infection or pathogens' classification with various testing methods and the more sensible and timely antibiotic cover are critical to the outcome of BSI after HSCT.

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

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

Application of Phagotherapy in the Treatment of Burn Patients (Review)

Treatment of patients with a burn injury is a complex process involving multicomponent multidirectional intensive therapy of the majority of organs and systems damaged by thermal effects on the skin, alternating with repeated surgical interventions aimed at removing nonviable tissues with subsequent plastic closure of wound defects. After the recovery from the burn shock, local infectious complications are considered to be the leading problem that decelerates the process of recovery and is the main cause of lethal outcomes. Since the skin integrity is broken, microorganisms penetrate readily into the internal environment of the human organism resulting in a septic state with multiple organ failure. A widespread and often uncontrollable use of antibacterial drugs in medical practice has led to the emergence of multiple drug resistance (MDR) in microorganisms. Introduction of drugs made on the basis of bacteriophages into practice is presently becoming increasingly important. This is confirmed by the growing interest in this field of pharmacology, the development of special programs aimed at studying the processes of phage and bacterial cell interaction. This review presents the main types of bacteria pertaining to MDR pathogens, principles of their classification, and the risk factors for infecting patients. The mechanisms of the selective action of phage particles on a bacterial cell and the possibility of using phage therapy in the treatment of burn injury (experimental and clinical data) based on the analysis of foreign literature are demonstrated as well as new positive properties of phages related to the changes in the macroorganism immune status caused by the interaction with bacteriophage particles.

Intensive oral care can reduce bloodstream infection with coagulase-negative staphylococci after neutrophil engraftment in allogeneic hematopoietic stem-cell transplantation

PURPOSE

Bloodstream infection (BSI) is a major complication of allogeneic hematopoietic stem-cell transplantation (allo-SCT). There are several causes of BSI; in particular, severe oral mucositis (OM) can induce BSI due to coagulase-negative staphylococci (CoNS). The OM severity may be reduced with intensive oral care. Thus, we evaluated whether the type of oral care affects the BSI incidence eventually.

METHOD

We performed retrospective analysis on 206 recipients who underwent allo-SCT from 2006 to 2017 at our institute. Intensive oral care by a dental specialist was performed for 111 recipients (intensive-care group) and self-oral care was performed by 95 recipients (self-care group). Incidence of BSI was assessed by type of the oral care, before neutrophil engraftment (pre-E-BSI) and after neutrophil engraftment (post-E-BSI) period until 180 days after allo-SCT.

RESULT

A total of 112 BSI occurred in 90 of the 206 recipients and 120 bacteria were identified, with CoNS being the most prevalent. There was no significant difference in the incidence of pre-E-BSI between the self-care and intensive-care groups (30.8% and 30.6%, respectively; P = 0.508). Meanwhile, the incidence of post-E-BSI was significantly lower in the intensive-care group than in the self-care group (14.3% and 28.6%; P = 0.008). In addition, the intensive-care group had significantly lower incidence of post-E-BSI with CoNS than the self-care group (8.5% and 21.5%, respectively; P = 0.009).

CONCLUSION

Intensive oral care through the period of allo-HCT can significantly reduce the post-E-BSI occurrence, especially due to CoNS.

Diagnostic yield of routine daily blood culture in patients on veno-arterial extracorporeal membrane oxygenation

BACKGROUND

Bloodstream infections (BSIs) are frequent on veno-arterial extracorporeal membrane oxygenation (V-A ECMO). Performing routine blood cultures (BCs) may identify early paucisymptomatic BSIs. We investigated the contribution of systematic daily BCs to detect BSIs on V-A ECMO.

METHODS

This was a retrospective study including all adult patients requiring V-A ECMO and surviving more than 24 h. Our protocol included routine daily BCs, from V-A ECMO insertion up to 5 days after withdrawal; other BCs were performed on-demand.

RESULTS

On the 150 V-A ECMO included, 2146 BCs were performed (1162 routine and 984 on-demand BCs); 190 (9%) were positive, including 68 contaminants. Fifty-one (4%) routine BCs revealed BSIs; meanwhile, 71 (7%) on-demand BCs revealed BSIs (p = 0.005). Performing routine BCs was negatively associated with BSIs diagnosis (OR 0.55, 95% CI [0.38; 0.81], p = 0.002). However, 16 (31%) BSIs diagnosed by routine BCs would have been missed by on-demand BCs. Independent variables for BSIs diagnosis after routine BCs were: V-A ECMO for cardiac graft failure (OR 2.43, 95% CI [1.20; 4.92], p = 0.013) and sampling with on-going antimicrobial therapy (OR 2.15, 95% CI [1.08; 4.27], p = 0.029) or renal replacement therapy (OR 2.05, 95% CI [1.10; 3.81], p = 0.008). Without these three conditions, only two BSIs diagnosed with routine BCs would have been missed by on-demand BCs sampling.

CONCLUSIONS

Although routine daily BCs are less effective than on-demand BCs and expose to contamination and inappropriate antimicrobial therapy, a policy restricted to on-demand BCs would omit a significant proportion of BSIs. This argues for a tailored approach to routine daily BCs on V-A ECMO, based on risk factors for positivity.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Potential of ultrasound in allogeneic stem cell transplantation and transplant-related complications]

Allogeneic hematopoietic stem cell transplantation (HCT) is a complex therapeutic procedure causing significant morbidity and mortality, including the gastrointestinal tract. Early diagnosis and treatment of HCT-associated complications are, therefore, of utmost importance to improve overall HCT outcome. Sonography can be a powerful diagnostic tool and is easily accessible at the bedside of HCT patients. In the hands of a sonography-experienced physician, it allows for instant diagnosis and can also rule out several important transplant-associated complications. Here we review available evidence on the diagnostic and clinical value of ultrasound prior, during and after HCT.

The impact of graft cell source on bloodstream infection in the first 100 days after allogeneic hematopoietic cell transplantation

Bloodstream infection (BSI) is a major infectious complication after allogeneic hematopoietic cell transplantation (HCT). To clarify the impact of graft cell source on the incidence of BSI after transplantation, we retrospectively examined 782 adult patients receiving their first allogeneic HCT: 122 recipients of related peripheral blood stem cells or bone marrow, 215 recipients of unrelated bone marrow, and 445 recipients of unrelated umbilical cord blood (U-CB). The cumulative incidence of BSI was 42.5% at 100 days after transplantation (95% confidence interval, 39.0-46.0). Gram-positive cocci were present in 64.2% of detected isolates. Among the pre-transplant factors including age, performance status, primary disease, disease status, graft cell source, sex and ABO blood type matching, and the intensity of conditioning regimen, U-CB use was identified as the most significant risk factor for BSI by multivariate analysis (hazard ratio, 1.76; 95% confidence interval, 1.40-2.22; p < 0.00001). Among the U-CB recipients, those who are not in remission at the time of transplantation were at the greatest risk of BSI (hazard ratio, 1.69; 95% confidence interval, 1.14-2.50; p < 0.01). The study makes it clear that graft cell source has an impact on BSI development after allogeneic HCT.

Chlorhexidine gluconate bathing in children with cancer or those undergoing hematopoietic stem cell transplantation: A double-blinded randomized controlled trial from the Children's Oncology Group

BACKGROUND

To the authors' knowledge, information regarding whether daily bathing with chlorhexidine gluconate (CHG) reduces central line-associated bloodstream infection (CLABSI) in pediatric oncology patients and those undergoing hematopoietic stem cell transplantation (HCT) is limited.

METHODS

In the current multicenter, randomized, double-blind, placebo-controlled trial, patients aged ≥2 months and <22 years with cancer or those undergoing allogeneic HCT were randomized 1:1 to once-daily bathing with 2% CHG-impregnated cloths or control cloths for 90 days. The primary outcome was CLABSI. Secondary endpoints included total positive blood cultures, acquisition of resistant organisms, and acquisition of cutaneous staphylococcal isolates with an elevated CHG mean inhibitory concentration.

RESULTS

The study was stopped early because of poor accrual. Among the 177 enrolled patients, 174 were considered as evaluable (88 were randomized to the CHG group and 86 were randomized to the control group). The rate of CLABSI per 1000 central line days in the CHG group was 5.44 versus 3.10 in the control group (risk difference, 2.37; 95% confidence interval, 0.05-4.69 [P = .049]). Post hoc conditional power analysis demonstrated a 0.2% chance that the results would have favored CHG had the study fully enrolled. The rate of total positive blood cultures did not differ between groups (risk difference, 2.37; 95% confidence interval, -0.41 to 5.14 [P = .078]). The number of patients demonstrating the new acquisition of resistant organisms did not differ between groups (P = .54). Patients in the CHG group were found to be more likely to acquire cutaneous staphylococcal isolates with an elevated CHG mean inhibitory concentration (P = .032).

CONCLUSIONS

The data from the current study do not support the use of routine CHG bathing in children with cancer or those undergoing allogeneic HCT.

Targeting the gut microbiome: An emerging trend in hematopoietic stem cell transplantation

Mounting evidence has demonstrated the critical role of the gut microbiome in different cancer treatment modalities showing intensive crosstalk between microbiota and the host immune system. In cancer patients receiving hematopoietic stem cell transplantation (HSCT), conditioning regimens including chemotherapy, radiotherapy, and immunosuppressive therapy, as well as antimicrobial prophylaxis, result in intestinal barrier disruption and massive changes in microbiota composition. According to clinical studies, a drastic loss of microbial diversity during HSCT is associated with enhanced pro-inflammatory immune response and an increased risk of transplant-related complications such as graft-versus-host disease (GvHD) and mortality. In this review, we outline the current understanding of the role of microbiota diversity in the patient response to cancer therapies and highlight the impact of changes in the gut microbiome on clinical outcomes in post-HSCT patients. Moreover, the therapeutic implications of microbiota modulation by probiotics, prebiotics, and fecal microbiota transplantation (FMT) in hematologic cancer patients receiving HSCT are discussed.

Characteristics of gram-negative bacteremia during febrile neutropenia among allogeneic hematopoietic stem cell transplant recipients on levofloxacin prophylaxis

The aim of this study is to clarify the characteristics of gram-negative bacteremia (GNB), including extended-spectrum β-lactamase (ESBL)-producing pathogens, among allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients on levofloxacin (LVFX) prophylaxis. A retrospective analysis on GNB at the first episode of febrile neutropenia (FN) was conducted among allo-HSCT recipients (age ≥ 20 years) on 500 mg/day of oral LVFX prophylaxis. Epidemiological and microbiological features of GNB were investigated and compared between the inappropriate and appropriate empiric therapy groups. In total, FN occurred in 414 allo-HSCT cases, and bacteremia at the first episode of FN occurred in 169 cases. Overall, 29 GNB cases were documented, and the causative organisms identified were Escherichia coli in 21 cases (including 10 ESBLs), Klebsiella pneumoniae in 2, Pseudomonas aeruginosa in 2, and other in 4. The crude 30-day mortality rate was not significantly different among cases of GNB (6.9%), gram-positive bacteremia (GPB) (7.1%), or non-bacteremia (5.4%; P = 0.78). Cefepime (CFPM) was administered in all cases in the inappropriate empiric therapy group, and all causative organisms were ESBL-producing E. coli (ESBL-EC). All patients in the inappropriate empiric therapy group had a low Pitt bacteremia score (≤ 2). Thirty-day mortality did not differ significantly between the inappropriate and appropriate empiric therapy groups (1/10 vs. 1/15, P = 0.61). In conclusion, GNB was not a significant cause of death. In LVFX breakthrough ESBL-EC bacteremia among allo-HSCT recipients, the administration of CFPM as empiric therapy did not lead to significantly poor prognosis. Empiric CFPM administration might be an acceptable strategy.

Intercontinental study on pre-engraftment and post-engraftment Gram-negative rods bacteremia in hematopoietic stem cell transplantation patients: Risk factors and association with mortality

OBJECTIVES

We present here data on Gram-negative rods bacteremia (GNRB) rates, risk factors and associated mortality.

METHODS

Data on GNRB episodes were prospectively collected in 65 allo-/67 auto-HSCT centers in 24 countries (Europe, Asia, Australia). In patients with and without GNRB, we compared: demography, underlying disease, HSCT-related data, center` fluoroquinolone prophylaxis (FQP) policy and accreditation status, and involvement of infection control team (ICT).

RESULTS

The GNRB cumulative incidence among 2818 allo-HSCT was: pre-engraftment (pre-eng-allo-HSCT), 8.4 (95% CI 7-9%), post-engraftment (post-eng-allo-HSCT), 5.8% (95%CI: 5-7%); among 3152 auto-HSCT, pre-eng-auto-HSCT, 6.6% (95%CI: 6-7%), post-eng-auto-HSCT, 0.7% (95%CI: 0.4-1.1%). GNRB, especially MDR, was associated with increased mortality. Multivariate analysis revealed the following GNRB risk factors: (a) pre-eng-allo-HSCT: south-eastern Europe center location, underlying diseases not at complete remission, and cord blood source; (b) post-eng-allo-HSCT: center location not in northwestern Europe; underlying non-malignant disease, not providing FQP and never accredited. (c) pre-eng-auto-HSCT: older age, autoimmune and malignant (vs. plasma cell) disease, and ICT absence.

CONCLUSIONS

Benefit of FQP should be explored in prospective studies. Increased GNRB risk in auto-HSCT patients transplanted for autoimmune diseases is worrying. Infection control and being accredited are possibly protective against bacteremia. GNRB are associated with increased mortality.

Patterns of infection and infectious-related mortality in patients receiving post-transplant high dose cyclophosphamide as graft-versus-host-disease prophylaxis: impact of HLA donor matching

Post-transplant cyclophosphamide (PTCy) has become a promising option after allo-SCT, but infections may be more common than in traditional protocols. We herein report 117 consecutive adults who received PTCy-based alloSCT in our hospital: HaploSCT (34%), MRD (19%), and VUD (47%), respectively. The 18-month incidence of severe bacterial, viral, and IFI was 56%, 69%, and 8.7%, without differences between donor type, except for CMV infection and viral hemorrhagic cystitis, which had a higher incidence in the haploSCT cohort (58% vs. 43% and 30% vs. 8% on day +90, p < 0.05). Late infections by conventional respiratory viruses were common in all groups [33/87 (38%)]. The 2-year survival was 72% and did not differ by donor type. IRM at day 30, day 100, and 18 months was 1.7%, 4.4%, and 12%, without differences by donor type (p = 0.7). The primary cause of IRM was bacterial infection (42%). Grade 2–4 acute GvHD was the only independent predictor of IRM. Donor type had no impact on IRM or on survival. In our study, severe infections were common in all donor types using PTCy, with higher rates of early post-engraftment CMV-I and viral HC in haploSCT recipients, although lethal infections were uncommon and similar in all donor types.

Microbiology of Bloodstream Infections in Children After Hematopoietic Stem Cell Transplantation: A Single-Center Experience Over Two Decades (1997-2017)

Background

Bloodstream infections (BSIs) occur frequently after hematopoietic stem cell transplantation (HSCT). We examined the microbiology of BSI in pediatric HSCT recipients over a 2-decade period at our institution to inform empirical antimicrobial prescribing and infection prevention strategies.

Methods

We conducted a retrospective cohort study of children (<18 years) who underwent HSCT at Duke University between 1997 and 2015. We used recurrent-event gap-time Cox proportional hazards models to determine the hazards of all-cause and cause-specific BSI according to HSCT year. We compared the median time to BSI by causative organism type and evaluated for temporal trends in the prevalence of antibiotic resistance among causative organisms.

Results

A total of 865 BSI occurred in 1311 children, including 412 (48%) Gram-positive bacterial, 196 (23%) Gram-negative bacterial, 56 (6%) fungal, 23 (3%) mycobacterial, and 178 (21%) polymicrobial BSI. The hazard of all BSIs did not change substantially over time during the study period, but the hazard of fungal BSIs declined over time during the study period (P = .04). Most fungal BSIs (82%) occurred in the first 100 days after HSCT, whereas mycobacterial BSIs occurred later after HSCT than BSIs caused by other organisms (P < .0001). The prevalence of vancomycin resistance among BSIs caused by Enterococcus faecium increased during the study period (P = .0007). The risk of 2-year mortality in children was increased with BSI (P = .02), Gram-negative bacterial BSI (P = .02), and fungal BSI (P < .0001).

Conclusions

Despite expanded practices for BSI prevention over the past several decades, the incidence of BSI remains high in pediatric HSCT recipients at our institution. Additional strategies are urgently needed to effectively prevent BSIs in this high-risk population.

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.

Sepsis secondary to multifocal Enterococcus faecium infection: A case report

INTRODUCTION

Nosocomial Enterococcus faecium (E faecium) infections are common among immunocompromised patients; however, sepsis caused by E faecium is rarely encountered in the clinical setting.

PATIENT CONCERNS

A 69-year-old woman with a previous history of tuberculosis (TB), developed symptoms of recurrent fever, paroxysmal cough, and exertional dyspnea for over 2 months before she presented to the hospital.

DIAGNOSIS

The patient was initially misdiagnosed with recurrent TB, and did not respond to anti-TB therapy. Culture results of blood, endotracheal necrotic tissue, and urine confirmed a diagnosis of multifocal E faecium infection.

INTERVENTIONS

On definitive diagnosis, the patient received intensive antimicrobial combination treatment with linezolid, teicoplanin, caspofungin, and voriconazole on the basis of antimicrobial susceptibility results.

OUTCOMES

After transient improvement, the patient's condition deteriorated due to secondary infections, and the patient died after discharge against medical advice.

CONCLUSION

E faecium bacteremia may cause sepsis in immunocompromised patients, and has a high mortality rate. Careful pathogen detection and early initiation of treatment is crucial to good patient outcome.

Bloodstream Infections and Delayed Antibiotic Coverage Are Associated With Negative Hospital Outcomes in Hematopoietic Stem Cell Transplant Recipients

BACKGROUND

Bloodstream infections (BSIs) are common after hematopoietic stem cell transplantation (HSCT) and are associated with increased long-term morbidity and mortality. However, short-term outcomes related to BSI in this population remain unknown. More specifically, it is unclear whether choices related to empiric antimicrobials for potentially infected patients are associated with patient outcomes.

RESEARCH QUESTION

Are potential delays in appropriate antibiotics associated with hospital outcomes among HSCT recipients with BSI?

STUDY DESIGN AND METHODS

We conducted a retrospective cohort study at a large comprehensive inpatient academic cancer center between January 2014 and June 2017. We identified all admissions for HSCT and prior recipients of HSCT. We defined potential delay in appropriate antibiotics as > 24 h between positive blood culture results and the initial dose of an antimicrobial with activity against the pathogen.

RESULTS

We evaluated 2,751 hospital admissions from 1,086 patients. Of these admissions, 395 (14.4%) involved one or more BSIs. Of these 395 hospitalizations, 44 (11.1%) involved potential delays in appropriate antibiotics. The incidence of mortality was higher in BSI hospitalizations than in those without BSI (23% vs 4.5%; P < .001). In multivariable analysis, BSI was an independent predictor of mortality (OR, 8.14; 95% CI, 5.06-13.1; P < .001). Mortality was higher for admissions with potentially delayed appropriate antibiotics than for those with appropriate antibiotics (48% vs 20%; P < .001). Potential delay in antibiotics was also an independent predictor of mortality in multivariable analysis (OR, 13.8; 95% CI, 5.27-35.9; P < .001).

INTERPRETATION

BSIs were common and independently associated with increased morbidity and mortality. Delays in administration of appropriate antimicrobials were identified as an important factor in hospital morbidity and mortality. These findings may have important implications for our current practice of empiric antibiotic treatment in HSCT patients.

Haploidentical Hematopoietic Stem Cell Transplantation Followed by 'Post-Cyclophosphamide': The Future of Allogeneic Stem Cell Transplant

Allogeneic hematopoietic cell transplant (Allo-HCT) is a potentially curative therapy for many malignant and nonmalignant hematological diseases. However, a suitable human leukocyte antigens (HLAs)-matched donor may not be available when the patient is in urgent need of a stem cell transplant. This challenge has been ameliorated to a large extent by the introduction of haploidentical donors. This type of donor shares one HLA haplotype with the recipient. Therefore, a patient's full sibling has a 50% chance of being haploidentical and a patient's biologic parents and children will all be haploidentical, thus providing an immediately accessible, motivated donor for almost every recipient. Haploidentical transplants previously incurred prohibitively poor outcomes, preventing their widespread use. However, several recent advances have dramatically improved the results, making them a more viable donor source. In this review, we discuss different types of donors used for Allo-HCT with a particular focus on the use of haploidentical donors and their future potential.

Microbiology and Risk Factors for Hospital-Associated Bloodstream Infections Among Pediatric Hematopoietic Stem Cell Transplant Recipients

Background

Children undergoing hematopoietic stem cell transplantation (HSCT) are at high risk for hospital-associated bloodstream infections (HA-BSIs). This study aimed to describe the incidence, microbiology, and risk factors for HA-BSI in pediatric HSCT recipients.

Methods

We performed a single-center retrospective cohort study of children and adolescents (<18 years of age) who underwent HSCT over a 20-year period (1997–2016). We determined the incidence and case fatality rate of HA-BSI by causative organism. We used multivariable Poisson regression to identify risk factors for HA-BSI.

Results

Of 1294 patients, the majority (86%) received an allogeneic HSCT, most commonly with umbilical cord blood (63%). During the initial HSCT hospitalization, 334 HA-BSIs occurred among 261 (20%) patients. These were classified as gram-positive bacterial (46%), gram-negative bacterial (24%), fungal (12%), mycobacterial (<1%), or polymicrobial (19%). During the study period, there was a decline in the cumulative incidence of HA-BSI (P = .021) and, specifically, fungal HA-BSIs (P = .002). In multivariable analyses, older age (incidence rate ratio [IRR], 1.03; 95% confidence interval [CI], 1.01–1.06), umbilical cord blood donor source (vs bone marrow; IRR, 1.69; 95% CI, 1.19–2.40), and nonmyeloablative conditioning (vs myeloablative; IRR, 1.85; 95% CI, 1.21–2.82) were associated with a higher risk of HA-BSIs. The case fatality rate was higher for fungal HA-BSI than other HA-BSI categories (21% vs 6%; P = .002).

Conclusions

Over the past 2 decades, the incidence of HA-BSIs has declined among pediatric HSCT recipients at our institution. Older age, umbilical cord blood donor source, and nonmyeloablative conditioning regimens are independent risk factors for HA-BSI among children undergoing HSCT.

Incidence, risk factors, and outcome of blood stream infections during the first 100 days post-pediatric allogeneic and autologous hematopoietic stem cell transplantations

Bloodstream infections (BSI) are a frequently observed complication after hematopoietic stem cell transplant (HSCT). Retrospective analysis of clinical and microbiological data during the first 100 days from 302 consecutive pediatric patients who underwent HSCT for a malignant disease at our institute between January 2013 and June 2017. A total of 164 patients underwent autologous and 138 allogeneic HSCT. The overall incidence of BSI was 37% with 92% of infectious episodes occurring during the pre-engraftment phase. Gram-positive bacteria (GPB) accounted for 54.6% of the isolated pathogens, gram-negative bacteria (GNB) for 43.9%, and fungi for 1.4%. Coagulase-negative staphylococci and Escherichia coli were the most commonly isolated GPB and GNB, respectively. Forty-five percent of GNB were extended-spectrum beta-lactamase producers and 21% were multidrug-resistant organisms. Fluoroquinolone resistance was 92% and 68%, among GPB and GNB, respectively. Risk factors for BSI in univariate analysis were allogeneic HSCT, delayed time to engraftment more than 12 days, previous BSI before HSCT, and alternative donor. In multivariate analysis, only HSCT type (allogeneic vs autologous P = .03) and previous BSI within 6 months before HSCT (P = .016) were significant. Overall survival at day 100 was 98% and did not differ significantly between patients with and without BSI (P = .76). BSI is common in children undergoing HSCT for malignant diseases. Allogeneic HSCT recipients and previous BSI within 6 months before HSCT are associated with increased risk of post-transplant BSI. With current supportive measures, BSI does not seem to confer an increased risk for 100-day mortality.

Infections after Allogenic Transplant with Post-Transplant Cyclophosphamide: Impact of Donor HLA Matching

Incidence and outcome of infections after allogeneic hematopoietic stem cell transplantation (HSCT) with post-transplant cyclophosphamide (PT-Cy) as graft-versus-host disease (GVHD) prophylaxis are largely unknown. Study aims were to estimate the incidence of pre-engraftment bloodstream infections (PE-BSIs) and viral infections (VIs; cytomegalovirus [CMV], adenovirus [ADV], human herpes virus 6 [HHV6], and BK-polyomavirus hemorrhagic-cystitis [BKPyV-HC]), their predictive factors, and infection-related mortality (IRM) after HSCT with PT-Cy. We analyzed 235 patients: 62%, 21%, and 17% received haploidentical (haplo), matched-unrelated donor (MUD), and matched-related donor, respectively. Overall, 72 patients had 77 PE-BSI episodes at a median time of 13 days after HSCT: cumulative incidence function (CIF) at 28 days was 32%, without differences among donor types (P = .988). By multivariate analysis, CIF of PE-BSI was higher in patients with severe neutropenia before HSCT (adjusted hazard ratio [AHR] = 2.90) and in multidrug-resistant Gram-negative bacteria rectal carriers (AHR = 2.68). IRM at 30 days was 5%, without differences by donor type (P = .106). Overall, 208 patients experienced ≥1 VIs (first occurrence among CMV, HHV6, ADV, BKPyV-HC) at a median time of 20 days after HSCT: CIF at 90 days was 91%, significantly higher in MUD and haplo (P = .0089). By multivariate analysis, also acute GVHD grade ≥2 (AHR = 1.32) and host/donor CMV-serology mismatch (positive/positive versus negative/negative: AHR = 2.95, positive/negative versus negative/negative: AHR = 2.41, negative/positive versus negative/negative: AHR = 2.35) affected VIs occurrence. IRM at 180 days was 8%, without differences among donor types (P = .106). In conclusion, study results did not show a significant impact of donor type on PE-BSI incidence; conversely, MUD and haploidentical transplants retained a higher occurrence of VIs in the early phase after HSCT.

Outcomes after bloodstream infection in hospitalized pediatric hematology/oncology and stem cell transplant patients

BACKGROUND

Pediatric hematology/oncology (PHO) patients receiving therapy or undergoing hematopoietic stem cell transplantation (HSCT) often require a central line and are at risk for bloodstream infections (BSI). There are limited data describing outcomes of BSI in PHO and HSCT patients.

METHODS

This is a multicenter (n = 17) retrospective analysis of outcomes of patients who developed a BSI. Centers involved participated in a quality improvement collaborative referred to as the Childhood Cancer and Blood Disorder Network within the Children's Hospital Association. The main outcome measures were all-cause mortality at 3, 10, and 30 days after positive culture date; transfer to the intensive care unit (ICU) within 48 hours of positive culture; and central line removal within seven days of the positive blood culture.

RESULTS

Nine hundred fifty-seven BSI were included in the analysis. Three hundred fifty-four BSI (37%) were associated with at least one adverse outcome. All-cause mortality was 1% (n = 9), 3% (n = 26), and 6% (n = 57) at 3, 10, and 30 days after BSI, respectively. In the 165 BSI (17%) associated with admission to the ICU, the median ICU stay was four days (IQR 2-10). Twenty-one percent of all infections (n = 203) were associated with central line removal within seven days of positive blood culture.

CONCLUSIONS

BSI in PHO and HSCT patients are associated with adverse outcomes. These data will assist in defining the impact of BSI in this population and demonstrate the need for quality improvement and research efforts to decrease them.

Gram-negative Bacteremia in Children With Hematologic Malignancies and Following Hematopoietic Stem Cell Transplantation: Epidemiology, Resistance, and Outcome

Gram-negative rod (GNR) infections adversely affect the outcome of patients with malignancies and following hematopoietic stem cell transplantation (HSCT). This retrospective observational study aimed to describe the epidemiology, outcome, and resistance patterns of GNR bacteremia in children with hematologic malignancies (HM) and after HSCT during the period spanning from 2010 to 2014 in a tertiary children's hospital. A total of 270 children were included in the analysis; 65 (24%) developed 85 episodes of GNR bacteremia; the rate was 36/122 (29.5%) in post-HSCT and 29/178 (16.3%) in HM patients (P<0.05). Overall, 10% of the GNRs were carbapenem resistant. In multivariate analysis, prolonged neutropenia (≥7 d; odds ratio: 19.5, 95% confidence interval: 2.6-148.4) and total hospitalization for a duration of >30 days in the last 3 months (odds ratio: 17.5, 95% confidence interval: 1.4-224.4) were associated with carbapenem-resistant GNR bacteremia. Thirty-day mortality following GNR bacteremia was 0% in HM and 7/52 episodes (13.5%) in HSCT patients (P<0.05). Carbapenem-resistant versus carbapenem-sensitive bacteremia was associated with longer duration of bacteremia (mean: 3.8 vs. 1.7 d), higher risk for intensive care unit hospitalization (44.4% vs. 10.1%), and higher mortality rate (33% vs. 5.8%) (P<0.05). To summarize, GNR bacteremia was frequent, especially in post-HSCT children. Carbapenem resistance adversely affects patients' outcome, increasing morbidity and mortality. Empirical antibiotic therapy must be adjusted to the local resistance patterns.

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

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

Allogeneic hematopoietic stem cell transplantation from unrelated donors is associated with higher infection rates in children with acute lymphoblastic leukemia-A prospective international multicenter trial on behalf of the BFM-SG and the EBMT-PDWP

Severe infections (SI) significantly impact on non‐relapse mortality after hematopoietic stem cell transplantation (HSCT). We assessed 432 children and adolescents with acute lymphoblastic leukemia (ALL) after total body irradiation based myeloablative HSCT within the multicenter ALL‐BFM‐SCT 2003 trial for SI grade 3 or higher according to common terminology criteria for adverse events. A total 172 patients experienced at least one SI. Transplantation from matched unrelated donors (MUD) was associated with any type of SI in the pre‐engraftment period (hazard ratio [HR]: 2.57; P < .001), and with any SI between day +30 and + 100 (HR: 2.91; P = .011). Bacterial (HR: 2.24; P = .041) and fungal infections (HR: 4.06; P = .057) occurred more often in the pre‐engraftment phase and viral infections more often before day +30 (HR: 2.66; P = .007) or between day +30 and + 100 (HR: 3.89; P = .002) after HSCT from MUD as compared to matched sibling donors. Chronic GvHD was an independent risk factor for any type of SI after day +100 (HR: 2.57; P < .002). We conclude that allogeneic HSCT from MUD in children and adolescents with pediatric ALL is associated with higher infection rates, which seems attributable to an intensified GvHD prophylaxis including serotherapy and methotrexate.

Gut Colonization Preceding Mucosal Barrier Injury Bloodstream Infection in Pediatric Hematopoietic Stem Cell Transplantation Recipients

The gastrointestinal tract is the predicted reservoir for most bloodstream infections (BSIs) after hematopoietic stem cell transplantation (HSCT). Whole-genome sequencing and comparative genomics have the potential to improve our understanding of the dynamics of gut colonization that precede BSI in HSCT recipients. Within a prospective cohort study of children (age <18 years) undergoing HSCT, 9 subjects met criteria for mucosal barrier injury BSI. We performed whole-genome sequencing of the blood culture isolate and weekly fecal samples preceding the BSI to compare the genetic similarity of BSI isolates to fecal strains. We evaluated temporal associations between antibiotic exposures and the abundances of BSI strains in the gut microbiota and correlated the detection of antibiotic resistance genes with the phenotypic antibiotic resistance of these strains. The median patient age was 2.6 years, and 78% were male. BSIs were caused by Escherichia coli (n = 5), Enterococcus faecium (n = 2), Enterobacter cloacae (n = 1), and Rothia mucilaginosa (n = 1). In the 6 BSI episodes with evaluable comparative genomics, the fecal strains were identical to the blood culture isolate (>99.99% genetic similarity). Gut domination by these strains preceded only 4 of 7 E. coli or E. faecium BSIs by a median of 17 days (range, 6 to 21 days). Increasing abundances of the resulting BSI strains in the gut microbiota were frequently associated with specific antibiotic exposures. E. cloacae and R. mucilaginosa were not highly abundant in fecal samples preceding BSIs caused by these species. The detection of antibiotic resistance genes for β-lactam antibiotics and vancomycin predicted phenotypic resistance in BSI strains. Bacterial strains causing mucosal barrier injury BSI in pediatric HSCT recipients were observed in the gut microbiota before BSI onset, and changes in the abundances of these strains within the gut preceded most BSI episodes. However, frequent sampling of the gut microbiota and sampling of other ecological niches is likely necessary to effectively predict BSI in HSCT recipients.

Parameters influencing the pharmacokinetics/pharmacodynamics of piperacillin/tazobactam in patients with febrile neutropenia and haematological malignancy: a prospective study

Objectives

To assess population pharmacokinetics (PK) and pharmacodynamics (PD) of both piperacillin and tazobactam in neutropenia patients and examine dosage requirements related to the MIC distribution for Gram-negative bacteria involved in bloodstream infections (BSIs).

Methods

We conducted a prospective study including adult haematological malignancy patients with febrile neutropenia receiving piperacillin/tazobactam as short (30 min) or prolonged (4 h) intravenous infusions. Concentration data were analysed using a population approach. Dosing simulations with the final model investigated factors influencing the PK/PD of piperacillin/tazobactam quantified by fT>MIC or PTA for piperacillin and tazobactam, respectively. In parallel, the local MIC distribution of β-lactams was documented for Gram-negative bacteria involved in BSIs.

Results

Over 10 months, 31 patients were enrolled, with 11 (35.5%) short and 20 (64.5%) prolonged infusion regimens. A one-compartment model adequately described the data for both drugs. Prolonged infusion, increased serum alkaline phosphatase (ALP) values and renal function impairment were associated with increased piperacillin fT>MIC. For patients with normal or augmented renal CL, dosing regimens q8h or q6h with 30 min of infusion were insufficient to achieve acceptable PTA for piperacillin/tazobactam at the median MIC value of 8 mg/L. Prolonged infusion of large doses was associated with the best PTA for both piperacillin and tazobactam.

Conclusions

In a population of haematological malignancy patients with neutropenia, renal function and ALP influenced the PK of piperacillin/tazobactam. Prolonged intravenous infusion would optimize the PK of piperacillin/tazobactam, especially in the case of augmented renal CL and/or low-range bacterial susceptibility.

Early versus late onset bloodstream infection during neutropenia after high-dose chemotherapy for hematologic malignancy

PURPOSE

The length of neutropenia has a significant impact on the incidence of bloodstream infection (BSI) in cancer patients, but limited information is available about the pathogen distribution in late BSI.

METHODS

Between 2002 and 2014, BSI episodes in patients with neutropenia receiving chemotherapy for hematologic malignancies were prospectively identified by multicenter, active surveillance in Germany, Switzerland and Austria. The incidence of first BSI episodes, their microbiology and time to BSI onset during the first episode of neutropenia of 15,988 patients are described.

RESULTS

The incidence rate of BSI episodes was 14.7, 8.7, and 4.7 per 1000 patient-days in the first, second, and third week of neutropenia, respectively. BSI developed after a median of 5 days of neutropenia (interquartile range [IQR] 3-10 days). The medium duration of neutropenia to BSI onset was 4 days in Escherichia coli (IQR 3-7 days), Klebsiella spp. (2-8 days), and Staphylococcus aureus (3-6 days). In contrast, BSI due to Enterococcus faecium occurred after a median of 9 days (IQR 6-14 days; p < 0.001 vs. other BSI). Late onset of BSI (occurring after the first week of neutropenia) was also observed for Stenotrophomonas maltophilia (12 days, IQR 7-17 days; p < 0.001), and non-albicans Candida spp. (13 days, IQR 8-19 days; p < 0.001).

CONCLUSIONS

Over the course of neutropenia, the proportion of difficult to treat pathogens such as E. faecium, S. maltophilia, and Candida spp. increased. Among other factors, prior duration of neutropenia may help to guide empiric antimicrobial treatment in febrile neutropenia.

Incidence and Outcomes of Bacterial Bloodstream Infections during Acute Graft-versus-Host Disease Involving the Gastrointestinal Tract after Hematopoietic Cell Transplantation

Despite the association of acute graft-versus-host disease (aGVHD) and bacterial bloodstream infections (BSIs) in hematopoietic cell transplant (HCT) recipients, relatively little is known about BSIs, specifically during gastrointestinal (GI) tract aGVHD (aGHVD-GI). The purpose of this study was to evaluate the incidence, risk factors, and mortality of BSIs complicating aGVHD-GI. This was a retrospective review of adult HCT recipients with grades I to IV aGVHD-GI between January 2009 and October 2017 at Oregon Health and Sciences University. BSIs occurring within 30 days of onset of aGVHD-GI were included. BSIs were categorized as "clinical" or "surveillance" based on chart review. A subgroup analysis of patients with grade IV aGVHD-GI examined potential BSI risk factors and cumulative survival at 30 and 45 days after onset of aGVHD-GI. Included were 229 patients. There were 45 unique BSIs in 39 patients (17%): 31 clinical (68.9%) and 14 surveillance (32.1%). The median time from aGVHD-GI onset to BSI was 18.5 days. BSIs were significantly more common during grade IV aGVHD-GI compared with grades I, II, or III. Fifty-two organisms were isolated during BSIs: 23 (44.2%) gram-positive and 29 (55.8%) gram-negative. Sixteen BSIs (36%) occurred during antibiotic exposure, and those were more likely to be caused by multidrug-resistant organisms. Prior BSI occurring between the time of HCT and onset of aGVHD-GI and receipt of etanercept for steroid-refractory aGVHD-GI were independently associated with BSI. Eight patients, all with grade IV aGVHD, representing 30.8% of patients with BSI in this subgroup, experienced infection-associated mortality. Cumulative survival at days 30 and 45 after onset of grade IV aGVHD-GI was similar among patients with and without BSI. BSI is a common complication of grade IV aGVHD-GI, resulting in significant infection-associated mortality. Interventions targeting those at highest risk may be warranted.

G-CSF-primed haplo-identical HSCT with intensive immunosuppressive and myelosuppressive treatments does not increase the risk of pre-engraftment bloodstream infection: a multicenter case-control study

A multicenter retrospective study in 131 patients (44 females/87 males) with hematological disorders who underwent G-CSF-primed/haplo-identical (Haplo-ID) (n = 76) or HLA-identical (HLA-ID) HSCT (n = 55) from February 2013 to February 2016 was conducted to compare the incidence and risk factors for pre-engraftment bloodstream infection (PE-BSI). In the Haplo-ID group, 71/76 patients with high-risk (n = 28) or relapsed/refractory hematological malignancies (n = 43) received FA5-BUCY conditioning (NCT02328950). All received trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis. Blood cultures and catheter tip cultures were obtained to confirm the BSI. PE-BSI was detected in 24/131 HSCT patients (18/76 in Haplo-ID and 6/55 in HLA-ID) after 28 febrile neutropenic episodes. Among 28 isolates for the 24 patients, 21 (75%) were G^neg bacteria, 6 (21.4%) G^pos and 1 (3.6%) fungi. Bacteria sources were central venous line infection (7/29.2%), gastroenteritis (6/25%), lower respiratory tract infection (LRTI; 5/20.8%), perianal skin infection (4/16.7%), and unknown (2/8.3%). The duration of neutropenia (P = 0.046) and previous G^neg bacteremia (P = 0.037) were important risk factors by univariate analysis, while the type of HSCT was not. A trend of TMP-SMX-resistant BSI in both groups may be due to routine antibacterial prophylaxis strategies. Our data show that G-CSF-primed Haplo-ID HSCT did not increase the risk of PE-BSI, even with intensive immunosuppressive treatments.

Febrile Neutropenia in Transplant Recipients

Febrile neutropenic patients are at increased risk of developing infections. During the initial stages of neutropenia, most of these infections are bacterial. The spectrum of bacterial infections depends to some extent on whether or not patients receive antimicrobial prophylaxis when neutropenic. Since most transplant recipients do, Gram-positive organisms predominate, due to the fact prophylaxis is directed primarily against Gram-negative organisms. Staphylococcus species (often methicillin-resistant), Streptococcus species (viridans group streptococci, beta-hemolytic streptococci), and Enterococcus species (including vancomycin-resistant strains) are isolated most often. Therefore, potent empiric Gram-positive coverage is recommended by many in this setting. Escherichia coli, Pseudomonas aeruginosa, and Klebsiella species are the most common Gram-negative pathogens isolated. Non-fermentative Gram-negative bacilli (Stenotrophomonas maltophilia, Acinetobacter species) are emerging as important pathogens. Many of these organisms acquire multiple mechanisms of resistance that render them multidrug resistant. The administration of prompt, broad-spectrum, empiric, antimicrobial therapy is essential and is generally based on local epidemiology and susceptibility/resistance patterns. Response rate to the initial regimen is generally in the range of 75–85%. Fungal infections develop in patients with prolonged neutropenia (greater than 7–10 days). Candida species and Aspergillus species are the predominant fungal pathogens, although many other fungi are opportunistic pathogens in this setting. Fungal infections are seldom documented microbiologically or on histopathology, and the administration of empiric antifungal therapy, when such infections are suspected, is the norm. Therapy is often prolonged, and outcomes are still suboptimal. The importance of infection control and antimicrobial stewardship cannot be overemphasized.

Bacterial blood stream infections (BSIs), particularly post-engraftment BSIs, are associated with increased mortality after allogeneic hematopoietic cell transplantation

We analyzed CIBMTR data to evaluate the incidence of non-relapse mortality (NRM) and association with overall survival (OS) for Bacterial blood stream infections (BSIs) occurring within 100 days of alloHCT in 2 different phases: pre/peri engraftment (BSI very early phase, BSI-VEP) and BSI post engraftment (BSI occurring between 2 weeks after engraftment and Day100, late early phase, BSI-LEP). Of 7,128 alloHCT patients, 2,656 (37%) had ≥1 BSI by day100. BSI-VEP, BSI-LEP, BSI-Both constituted 56% (n=1492), 31% (n=824), and 13% (n=340) of total BSI, respectively. Starting in 2009 we observed a gradual decline in BSI incidence through 2012 (61% to 48%). Patients with BSI-VEP were more likely to receive a myeloablative conditioning (MAC) regimen with total body irradiation (TBI). NRM was significantly higher in patients with any BSI (RR 1.82 95CI 1.63–2.04 for BSI-VEP, RR 2.46, 95%CI 2.05–2.96 for BSI-LEP, and RR 2.29, 95%CI 1.87–2.81 for BSI-Both) compared with those without BSI. OS was significantly lower in patients with any BSI compared with patients without BSI (RR 1.36, 95%CI 1.26–1.47 for BSI-VEP; RR 1.83, 95%CI 1.58–2.12 for BSI-LEP: RR 1.66, 95%CI 1.43–1.94 for BSI-Both). BSIs within day100 after alloHCT are common and remain a risk factor for mortality.

Infections in Allogeneic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has become a widely used modality of therapy for a variety of malignant and nonmalignant diseases. Despite advances in pharmacotherapy and transplantation techniques, infection remains one of the most severe and frequently encountered complications of allo-HSCT.

This chapter will address the risk factors for development of infection following allo-HSCT, including those related to the host, the conditioning regimen, and the graft, as well as the timing of opportunistic infections after allo-HSCT. The most common bacterial, viral, fungal, and parasitic infections, as well as issues surrounding their diagnostics and treatment, will be discussed. Finally, this chapter will address vaccination and other preventative strategies to be utilized when caring for patients undergoing allo-HSCT.

Gastrointestinal Graft-versus-Host Disease Is a Risk Factor for Postengraftment Bloodstream Infection in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Bloodstream infection (BSI) is a well-known cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. Here, we conducted a retrospective study to assess the morbidity, etiology, risk factors, and outcomes of BSI in the postengraftment period (PE-BSI) after allo-HSCT. Forty-three of 316 patients (13.6%) developed 57 PE-BSI episodes, in which 62 pathogens were isolated: Gram-positive bacteria, gram-negative bacteria, and fungi, respectively, accounted for 54.8%, 35.5%, and 9.7% of the isolates. Multivariate analysis revealed methylprednisolone use for graft-versus-host disease (GVHD) prophylaxis (odds ratio [OR], 6.49; 95% confidence interval [CI], 1.49 to 28.2; P = .013) and acute gastrointestinal GVHD (GI-GVHD) (OR, 8.82; 95% CI, 3.99 to 19.5; P < .0001) as risk factors for developing PE-BSI. This finding suggested that GI-GVHD increases the risk of bacterial translocation and subsequent septicemia. Moreover, among patients with GI-GVHD, insufficient response to corticosteroids, presumably related to an intestinal dysbiosis, significantly correlated with this complication. Patients with PE-BSI presented worse outcome compared with those without (3-year overall survival, 47.0% versus 18.6%; P < .001). Close microbiologic monitoring for BSIs and minimizing intestinal dysbiosis may be crucial to break the vicious cycle between GI-GVHD and bacteremia and to improve transplant outcomes especially in patients who require additional immunosuppressants.

Fecal microbiota transplantation reverses antibiotic and chemotherapy-induced gut dysbiosis in mice

Fecal microbiota transplantation (FMT) is now widely used to treat recurrent Clostridium difficile infection, but has been less studied as a means to restore microbiome diversity and composition following antibiotic or chemotherapy treatments. The purpose of our study was to assess the efficacy of FMT to reverse antibiotic- and chemotherapy-induced gut dysbiosis in a mouse model. C57BL/6J mice were treated with ampicillin for 1 week and/or received a single intraperitoneal injection of 5-Fluorouracil. Fresh stool was collected and analyzed using shotgun metagenomics and the Illumina sequencing platform. Ampicillin caused a significant and immediate decrease in bacterial species richness and diversity that persisted for one week. In mice that received FMT, disruption of the intestinal microbiota was reversed immediately. Antibiotic and chemotherapy administration caused significant alteration in species distribution, including a decrease in the relative proportions of Clostridium scindens and Faecalibacterium prausnitzii, and an increase in known pathogenic species. In mice receiving FMT, we observed a significant increase in species known to exhibit anti-inflammatory properties. Moreover, chemotherapy led to a critical decrease in key ‘health-promoting’ species and to an altered functional profile, especially when chemotherapy was administered in tandem with antibiotics, and that FMT can ameliorate these effects.

Early bacterial and fungal infection in children receiving allogeneic stem cell transplantation for acute lymphoblastic leukemia in Argentina

Infections are important complications associated with allogeneic HSCT. Describing infection rates in low- and middle-income countries provides data to infer efficacy of supportive care practices in these settings. In this retrospective cohort study, we included patients (age ≤ 18 years) who underwent a first allogeneic HSCT for ALL in a single center in Argentina between 1998 and 2016. The primary outcome was sterile site bacterial infection. Secondary outcomes were proven or probable invasive fungal infection, TRM, and infectious deaths. There were 68 allogeneic HSCT recipients with ALL included in this analysis. Overall, 17 (25.0%) experienced at least one sterile site bacterial infection and 10 (14.7%) experienced at least one proven or probable invasive fungal infection. The TRM rate was 19.1%, and 3 (4.4%) patients died of infection. In a middle-income country center in Argentina, pediatric allogeneic HSCT infection rates, TRM, and infection-related mortality were comparable to high-income countries. These data support continuation of allogeneic HSCT programs in similar resource-limited settings provided that adequate supportive care and monitoring of outcomes can be performed.

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.

A multi-center prospective study randomizing the use of fat emulsion in intensive glucose control after allogeneic hematopoietic stem cell transplantation using a myeloablative conditioning regimen

BACKGROUND & AIMS

Although parenteral nutrition (PN) is often used after allogeneic hematopoietic stem cell transplantation (allo-HSCT), there is controversy regarding PN management, for instance in the use of fat emulsion and glucose control (GC). To clarify these issues, we conducted a multi-center prospective study with intensive GC, randomizing the use of fat emulsion after allo-HSCT using a myeloablative conditioning regimen.

METHODS

The primary endpoint was the cumulative incidence of documented infectious disease, namely bacterial and fungal infection, at day 100 after allo-HSCT. Between August 2007 and March 2012, we enrolled 81 patients at 5 centers. Excluding 5 ineligible patients, 76 patients received the protocol treatment. The target fasting glucose level was 80-110 mg/dL.

RESULTS

The median follow-up of surviving patients was 1796 days. The cumulative incidences of documented infectious disease at day 100 were 16% (95% confidence interval [CI] 6-29%) in the no-fat group and 19% (95% CI 8-32%) in the fat group, indicating no significant difference. The mean glucose level at 28 days after allo-HSCT was 107 mg/dL in the no-fat group and 111 mg/dL in the fat group. Grade 3 hyperglycemia (>250 mg/dL) and grade 3 hypoglycemia (<40 mg/dL) occurred in 4 patients each (5.3%). Overall survival and non-relapse mortality rates at 4 years were 75% and 11% in the no-fat group and 69% and 8% in the fat group, respectively.

CONCLUSIONS

Irrespective of the use of fat emulsion, the long-term clinical outcomes of the enrolled patients were favorable under intensive GC. To further clarify the benefits of GC after allo-HSCT, a prospective study randomizing the level of GC is warranted.