Characteristics comparisons of bacteremia in allogeneic and autologous hematopoietic stem cell-transplant recipients with levofloxacin prophylaxis and influence on resistant bacteria emergence

The addition of doxycycline to fluoroquinolones for bacterial prophylaxis in autologous stem cell transplantation for multiple myeloma

BACKGROUND

Bacterial prophylaxis with a fluoroquinolone (FQ) during autologous stem cell transplant (ASCT) is common, although not standardized among transplant centers. The addition of doxycycline (doxy) to FQ prophylaxis was previously linked to reduced neutropenic fever and bacteremia in multiple myeloma (MM) patients undergoing ASCT although several confounders were present. We compared the incidence of neutropenic fever and bacteremia between MM patients variably receiving prophylaxis with FQ alone and FQ-doxy during ASCT.

METHODS

Systematic retrospective chart review of MM patients who underwent ASCT between January 2016 and December 2021. The primary objective was to determine the effect of bacterial prophylaxis on neutropenic fever and bacteremia within 30 days of ASCT. Multivariable logistic regression for neutropenic fever and univariate logistic regression for bacteremia accounted for differences in subject characteristics between groups.

RESULTS

Among 341 subjects, 121 received FQ and 220 received FQ-doxy for prophylaxis. Neutropenic fever developed in 67 (55.4%) and 87 (39.5%) subjects in the FQ and FQ-doxy groups, respectively (p = .005). Bacteremia was infrequent, with 5 (4.1%) and 5 (2.3%) cases developing in the FQ and FQ-doxy groups, respectively (p = .337). Among Gram-negative bacteremia events, 7/7 Escherichia coli strains were FQ-resistant, and 5/7 were ceftriaxone-resistant.

CONCLUSION

The FQ-doxy prophylaxis group had fewer cases of neutropenic fever than the FQ group, however, there was no significant difference in bacteremia. High rates of antibiotic resistance were observed. An updated randomized controlled trial investigating appropriate prophylaxis for ASCT in the context of current oncology standards and changing antimicrobial resistance rates is warranted.

The indirect effects of CMV reactivation on patients following allogeneic hematopoietic stem cell transplantation: an evidence mapping

Cytomegalovirus (CMV) reactivation following allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a challenging problem, and the impact on the risk of overall mortality (OM) and non-relapse mortality (NRM) in patients following allo-HSCT is still controversial. Utilizing the evidence mapping method, we aimed to assess the effect of CMV infection on outcomes of patients post-transplantation and identify research gaps through systematic reviews (SRs) and clinical studies. PubMed, EMBASE, Web of Science, and Cochrane library databases were searched from inception until 5 July 2022 to identify relevant literature. After systematic literature screening and data extraction, evidence mapping of the effects of CMV reactivation on patients post-allo-HSCT was conducted. Three SRs and 22 clinical studies were included. In one SR, CMV reactivation was associated with an increased risk of mortality (HR 1.46; 95% CI, 1.24-1.72; P ≤ 0.001). In two SRs, CMV reactivation was associated with NRM. One SR reported CMV reactivation was potentially associated with significant protection against relapse in patients with acute myelocytic leukemia (AML), but no significant correlation with graft-versus-host disease (GVHD) was found. Lastly, in one SR CMV reactivation significantly increased the risk of invasive fungal disease (IFD). Most clinical articles reported that CMV reactivation increased the risk of renal dysfunction, poor graft function, re-hospitalization, and bacterial infections. CMV reactivation following allo-HSCT is associated with an increased risk of OM, NRM, IFD, and renal dysfunction, as well as a reduced risk of relapse in patients with AML.

Lactoferricin B Combined with Antibiotics Exhibits Leukemic Selectivity and Antimicrobial Activity

The fusion of penetrating peptides (PPs), e.g., cell penetration peptides (CPPs) or antimicrobial peptides (AMPs), together with antimicrobial agents is an expanding research field. Specific AMPs, such as lactoferricin B (LfcinB), have demonstrated strong antibacterial, antifungal, and antiparasitic activity, as well as valuable anticancer activity, proving beneficial in the development of anticancer conjugates. The resulting conjugates offer potential dual functionality, acting as both an anticancer and an antimicrobial agent. This is especially necessary in cancer treatment, where microbial infections pose a critical risk. Leukemic cells frequently exhibit altered outer lipid membranes compared to healthy cells, making them more sensitive to compounds that interfere with their membrane. In this study, we revisited and reanalyzed our earlier research on LfcinB and its conjugates. Furthermore, we carried out new experiments with a specific focus on cell proliferation, changes in membrane asymmetric phosphatidylserine location, intracellular reactive oxygen species (ROS) generation, mitochondrial functions, and in vitro bacterial topoisomerase inhibition.

Dual-Activity Fluoroquinolone-Transportan 10 Conjugates Offer Alternative Leukemia Therapy during Hematopoietic Cell Transplantation

Hematopoietic cell transplantation (HCT) is often considered a last resort leukemia treatment, fraught with limited success due to microbial infections, a leading cause of mortality in leukemia patients. To address this critical issue, we explored a novel approach by synthesizing antileukemic agents containing antibacterial substances. This innovative strategy involves conjugating fluoroquinolone antibiotics, such as ciprofloxacin (CIP) or levofloxacin (LVX), with the cell-penetrating peptide transportan 10 (TP10). Here, we demonstrate that the resultant compounds display promising biologic activities in preclinical studies. These novel conjugates not only exhibit potent antimicrobial effects but are also selective against leukemia cells. The cytotoxic mechanism involves rapid disruption of cell membrane asymmetry leading to membrane damage. Importantly, these conjugates penetrated mammalian cells, accumulating within the nuclear membrane without significant effect on cellular architecture or mitochondrial function. Molecular simulations elucidated the aggregation tendencies of TP10 conjugates within lipid bilayers, resulting in membrane disruption and permeabilization. Moreover, mass spectrometry analysis confirmed efficient reduction of disulfide bonds within TP10 conjugates, facilitating release and activation of the fluoroquinolone derivatives. Intriguingly, these compounds inhibited human topoisomerases, setting them apart from traditional fluoroquinolones. Remarkably, TP10 conjugates generated lower intracellular levels of reactive oxygen species compared with CIP and LVX. The combination of antibacterial and antileukemic properties, coupled with selective cytostatic effects and minimal toxicity toward healthy cells, positions TP10 derivatives as promising candidates for innovative therapeutic approaches in the context of antileukemic HCT. This study highlights their potential in search of more effective leukemia treatments. SIGNIFICANCE STATEMENT: Fluoroquinolones are commonly used antibiotics, while transportan 10 (TP10) is a cell-penetrating peptide (CPP) with anticancer properties. In HCT, microbial infections are the primary cause of illness and death. Combining TP10 with fluoroquinolones enhanced their effects on different cell types. The dual pharmacological action of these conjugates offers a promising proof-of-concept solution for leukemic patients undergoing HCT. Strategically designed therapeutics, incorporating CPPs with antibacterial properties, have the potential to reduce microbial infections in the treatment of malignancies.

Clinical features of febrile neutropenia and bloodstream infection in autologous hematopoietic cell transplantation: Comparison to those in intensive chemotherapy for acute myeloid leukemia

BACKGROUND

In autologous hematopoietic cell transplantation (HCT), myelosuppression and mucosal damage are more severe than those in conventional chemotherapy because of high-dose chemotherapy, but the duration of neutropenia is shorter due to stem cell rescue.

METHODS

We retrospectively evaluated febrile neutropenia (FN) and bloodstream infection (BSI) in 208 patients who underwent their first autologous HCT at our institution between 2007 and 2019. They were compared to those in patients who underwent intensive chemotherapy for acute myeloid leukemia (AML) (130 induction/salvage and 191 consolidation).

RESULTS

The median neutropenic period in autologous HCT, AML induction/salvage and consolidation was 9, 26.5, and 19 days, respectively. The incidence of FN was 93.8%, 92.3%, and 81.7%, and that of BSI in initial FN was 7.2%, 7.5% and 26.3%, respectively. The incidence of oral mucositis (≥ grade 2) was 63.1%, 9.2% and 12.2%, and that of diarrhea (≥ grade 2) was 53.3%, 9.2% and 6.4%, respectively. Although there were significant differences in the incidence of shaking chills, the degree of fever and the value of CRP between patients with and without BSI in initial FN of AML chemotherapy, no significant risk factors or predictive factors for BSI were identified in autologous HCT.

CONCLUSIONS

The profile of infectious complications in autologous HCT was characterized by a high incidence of FN maybe due to mucosal damage. On the other hand, the incidence of BSI was lower compared to that in AML consolidation chemotherapy.

Bacterial Bloodstream Infections after Allogeneic Hematopoietic Stem Cell Transplantation: Etiology, Risk Factors and Outcome in a Single-Center Study

Background—Allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients are subject to major risks for bacterial bloodstream infections (BSIs), including emergent multidrug-resistant (MDR) organisms, which still represent the main cause of morbidity and mortality in transplanted patients. Methods: We performed an observational, retrospective, single-center study on patients undergoing allo-HSCT between 2004 and 2020 at the Stem Cell Transplant Unit in Turin to assess the incidence, etiology, and outcomes of BSIs and to explore any risk factors for bacteriaemia. Results: We observed a total of 178 bacterial BSIs in our cohort of 563 patients, resulting in a cumulative incidence of 19.4%, 23.8%, and 28.7% at 30, 100, and 365 days, respectively. Among isolated bacteria, 50.6% were Gram positive (GPB), 41.6% were Gram negative (GNB), and 7.9% were polymicrobial infections. Moreover, BSI occurrence significantly influenced 1-year overall survival. High and very high Disease Risk Index (DRI), an haploidentical donor, and antibacterial prophylaxis were found as results as independent risk factors for bacterial BSI occurrence in multivariate analysis. Conclusions: In our experience, GNB have overwhelmed GPB, and fluoroquinolone prophylaxis has contributed to the emergence of MDR pathogens. Local resistance patterns and patients’ characteristics should therefore be considered for better management of bacteremia in patients receiving an allogeneic HSCT.

Levofloxacin prophylaxis and parenteral nutrition have a detrimental effect on intestinal microbial networks in pediatric patients undergoing HSCT

The gut microbiome (GM) has shown to influence hematopoietic stem cell transplantation (HSCT) outcome. Evidence on levofloxacin (LVX) prophylaxis usefulness before HSCT in pediatric patients is controversial and its impact on GM is poorly characterized. Post-HSCT parenteral nutrition (PN) is oftentimes the first-line nutritional support in the neutropenic phase, despite the emerging benefits of enteral nutrition (EN). In this exploratory work, we used a global-to-local networking approach to obtain a high-resolution longitudinal characterization of the GM in 30 pediatric HSCT patients receiving PN combined with LVX prophylaxis or PN alone or EN alone. By evaluating the network topology, we found that PN, especially preceded by LVX prophylaxis, resulted in a detrimental effect over the GM, with low modularity, poor cohesion, a shift in keystone species and the emergence of modules comprising several pathobionts, such as Klebsiella spp., [Ruminococcus] gnavus, Flavonifractor plautii and Enterococcus faecium. Our pilot findings on LVX prophylaxis and PN-related disruption of GM networks should be considered in patient management, to possibly facilitate prompt recovery/maintenance of a healthy and well-wired GM. However, the impact of LVX prophylaxis and nutritional support on short- to long-term post-HSCT clinical outcomes has yet to be elucidated.

Bacteremia in Hematopoietic Stem Cell Recipients Receiving Fluoroquinolone Prophylaxis: Incidence, Resistance, and Risk Factors

Background

Bacteremia is a common complication in hematopoietic stem cell transplant (HSCT) recipients. Prophylactic fluoroquinolone is recommended and used in these individuals. Breakthrough infections can occur with fluoroquinolone-resistant strains. We aimed to identify the incidence, resistance, and risk factors for bacteremia in HSCT recipients receiving fluoroquinolone prophylaxis.

Materials and Methods

This retrospective study was performed on patients who received fluoroquinolone prophylaxis and underwent autologous and allogeneic HSCT between 2015 and 2019. The incidence of bacteremia, comorbidity, treatment, and invasive procedures was compared in these patients with and without bacteremia.

Results

There were 553 patients included in the study, 68 (12.3%) had bacteremia. The incidence of bacteremia is 8.2% of autologous HSCT recipients and 18.4% of allogeneic HSCT recipients. The significant risk factors associated with bacteremia were steroid-using (odds ratio [OR]:13.83, 95% confidence interval [CI]: 2.88 - 66.40), higher Charlson Comorbidity Index (CCI)-mean (OR: 1.57, 95% CI: 1.15 - 2.16), diabetes mellitus (OR: 4.29, 95% CI: 1.11 - 16.48) in autologous HSCT, steroid-using (OR: 6.84, 95% CI: 1.44 - 32.33), longer duration of neutropenia (OR: 1.05, 95% CI: 1.01 - 1.09) using central venous catheter (OR: 7.81, 95% CI: 1.00 - 61.23) in allogeneic HSCT. Seventy-three pathogens were isolated from a total of 68 bacteremia episodes. The most commonly occurring agents were Escherichia coli, Klebsiella pneumoniae and Enterococcus spp. Resistance to fluoroquinolones was 87.2%, 70.0% and 60.0% among these strains, respectively.

Conclusion

High CCI, diabetes mellitus, use of steroids and long-term neutropenia and use of central venous catheters were significantly associated with the breakthrough bacteremia in HSCT recipients receiving fluoroquinolone prophylaxis. Fluoroquinolone prophylaxis may reduce the incidence of bacteremia but may select strains resistant to fluoroquinolone.

Clinical Analysis of Bloodstream Infections During Agranulocytosis After Allogeneic Hematopoietic Stem Cell Transplantation

Purpose

To explore the epidemiological characteristics and risk factors of bloodstream infections (BSI) in patients who develop agranulocytosis fever after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study also provides a basis for the clinical treatment of BSI.

Methods

A retrospective analysis of 397 allo-HSCT patients in the Department of Hematology of our hospital was conducted from January 2013 to December 2017 to analyze the incidence of BSI, the distribution and types of pathogenic bacteria, and drug resistance rates. We also determined whether various parameters are risk factors to BSI, including the patient age, gender, disease type, transplantation method, stem cell source, pre-treatment with anti-thymocyte globulin (ATG), and agranulocytosis time.

Results

Among the 397 allo-HSCT patients, 294 had a fever during the period of agranulocytosis, and 52 cases were found to have BSI. The incidence of BSI in patients with agranulocytosis fever was 17.7% (52/294). Among the 60 pathogens detected, 43 (71.67%), 10 (16.67%), and 7 (11.67%) were Gram negative strains, Gram positive strains, and fungi, respectively. The most common bacteria were Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The detection rate of extended-spectrum β-lactamase (ESBL) was 40.0%, and carbapenem-resistant Enterobacteriaceae (CRE) accounted for 17.9%. Single-factor and multi-factor analyses showed that pre-treatment with ATG, agranulocytosis time (≥21 days), and stem cell source were risk factors for BSI.

Conclusion

We found that in our hospital, BSIs in allo-HSCT patients are mainly caused by Gram-negative bacteria, and the resistance rate to carbapenem drugs is high. Pre-treatment with ATG, agranulocytosis time (≥21 days), and stem cell source are risk factors for BSI.

Functional capacity, pulmonary function, and quality of life in hematopoietic stem cell transplantation survivors

OBJECTIVE

Hematopoietic stem cell transplantation (HSCT) is used as a treatment for several diseases. The objective was to evaluate the functional capacity, pulmonary function, and quality of life (QoL) in HSCT survivors.

METHODS

The patients were submitted to spirometry and six-minute walk test (6MWT) and evaluation of QoL (Functional Assessment of Cancer Therapy Bone Marrow Transplantation-FACT-BMT) and the level of physical activity (Human Activity Profile-HAP) in the post-HSCT outpatient ambulatory.

RESULTS

The sample was composed of 103 individuals with a mean age of 42.1 ± 12 and a median HSCT time of 5 (2-11) years. The average distance walked in the 6MWT was 524.7 ± 73.5 m; the FACT-BMT score, 82 ± 8.7 points; FEV₁, 76.8 ± 22.6%; and HAP, 71.9 ± 11.2 points. There was a significant difference between debilitated and physically active individuals for the variables: forced expiratory volume in the first second (FEV₁) in liters (p = 0.008) and % of predicted (p = 0.017), FEV₁/FVC (p = 0.032), distance on the 6MWT (p < 0.001), fatigue after the 6MWT (p < 0.001), and physical well-being (p = 0.005).

CONCLUSIONS

HSCT survivors have long-term changes in functional capacity, pulmonary function, and QoL. Subjects more active had better results in pulmonary function and functional capacity.

Levofloxacin for Antibacterial Prophylaxis in Pediatric Patients With Acute Myeloid Leukemia or Undergoing Hematopoietic Stem Cell Transplantation

OBJECTIVE

This study aimed to evaluate the use of levofloxacin for the prevention of bacterial infections in pediatric patients with acute myeloid leukemia or those undergoing hematopoietic stem cell transplantation.

METHODS

This study was a single-center, retrospective review designed to assess the frequency of bacteremia with levofloxacin prophylaxis compared with historical controls that used other, clinician-directed antibacterial prophylaxis. The primary outcome of the study was microbiologically documented bacteremia. Secondary outcomes included febrile neutropenia, clinically documented infection, duration of neutropenia, treatment antibiotic exposure days, Clostridioides difficile infection, and infection-related mortality.

RESULTS

Of the 60 patients included, 24 patients with 32 hospital admissions received levofloxacin and 36 patients with 48 hospital admissions received clinician-directed prophylaxis. There was no difference found in the frequency of bacteremia between levofloxacin and clinician-directed prophylaxis (15.6% vs 10.4%, p = 0.49). There was no difference in the incidence of febrile neutropenia, clinically documented infection, treatment antibiotic exposure days, or 30-day infection-related mortality between the 2 groups. The levofloxacin group had a longer mean duration of neutropenia compared with clinician-directed prophylaxis (26.8 days vs 16.4 days, p = 0.01).

CONCLUSIONS

There was no difference in bacteremia between levofloxacin prophylaxis and clinician-directed prophylaxis in pediatric patients with acute myeloid leukemia or those undergoing hematopoietic stem cell transplantation. Levofloxacin prophylaxis is an appropriate alternative for the prevention of serious bacterial infections in this patient population, although further studies are needed to confirm these results.

Cost-effectiveness of levofloxacin prophylaxis against bacterial infection in pediatric patients with acute myeloid leukemia

BACKGROUND

Infections are the leading cause of therapy-related mortality in pediatric patients with acute myeloid leukemia (AML). Although effectiveness of levofloxacin antibacterial prophylaxis in oncology patients is recognized, its cost-effectiveness is unknown. This study evaluated epidemiologic data regarding levofloxacin use and the cost-effectiveness of this strategy as the cost per bacteremia episode, intensive care unit (ICU) admission, and death avoided in children with AML.

PROCEDURE

A retrospective cohort study using the Pediatric Health Information System (PHIS) database compared demographic and clinical characteristics and receipt of levofloxacin prophylaxis in children with AML admitted for chemotherapy from January 1, 2014, through December 31, 2018. We then developed a decision analysis model in this population that compared costs associated with bacteremia, ICU admission, or death secondary to bacteremia to levofloxacin prophylaxis cost from a healthcare perspective. Time horizon is one chemotherapy cycle. Probabilistic and one-way sensitivity analyses evaluated model uncertainty.

RESULTS

Prophylaxis cost $8491 per bacteremia episode prevented compared with an average added hospital cost of $119 478. Prophylaxis cost $81 609 per ICU admission avoided, compared with an average added hospital cost of $94 181. Prophylaxis cost $220 457 per death avoided. In sensitivity analysis, at a willingness-to-pay threshold of $100 000 per bacteremia episode avoided, prophylaxis remained cost-effective in 94.6% of simulations. Prophylaxis use was more common in recent years in patients with relapsed disease and with chemotherapy regimens considered more intensive.

CONCLUSION

Prophylaxis is cost-effective in preventing bacterial infections in patients with AML. Findings support increased use in patients considered at high risk of bacterial infection secondary to myelosuppression.

Improving Oral Health and Modulating the Oral Microbiome to Reduce Bloodstream Infections from Oral Organisms in Pediatric and Young Adult Hematopoietic Stem Cell Transplantation Recipients: A Randomized Controlled Trial

Bloodstream infections (BSIs) from oral organisms are a significant cause of morbidity and mortality in hematopoietic stem cell transplantation (HSCT) recipients. There are no proven strategies to decrease BSIs from oral organisms. The aim of this study was to evaluate the impact of daily xylitol wipes in improving oral health, decreasing BSI from oral organisms, and modulating the oral microbiome in pediatric HSCT recipients. This was a single-center 1:1 randomized controlled trial in pediatric HSCT recipients age >2 years. Age-matched healthy children were enrolled to compare the oral microbiome. The oral hygiene standard of care (SOC) group continued to receive the standard oral hygiene regimen. The xylitol group received daily oral xylitol wipes (with .7 g xylitol) in addition to the SOC. The intervention started from the beginning of the transplantation chemotherapy regimen and extended to 28 days following transplantation. The primary outcome was oral health at interval time points, and secondary outcomes included BSIs from oral organisms in the first 30 days following transplantation, oral microbiome abundance, and diversity and oral pathogenic organism abundance. The study was closed early due to efficacy after an interim analysis of the first 30 HSCT recipients was performed (SOC group, n = 16; xylitol group, n = 14). The xylitol group had a significantly lower rate of gingivitis at days 7, 14, and 28 following transplantation (P = .031, .0039, and .0005, respectively); oral plaque at days 7 and 14 (P = .045 and .0023, respectively); and oral ulcers >10 mm at day 14 (P = .049) compared with the SOC group. The xylitol group had no BSI from oral organisms compared with the SOC group, which had 4 (P = .04). The xylitol group had significantly lower abundance of potential BSI pathogens, such as Staphylococcus aureus (P = .036), Klebsiella pneumoniae (P = .033), and Streptococcus spp (P = .011) at the day after transplantation compared with the SOC group. Healthy children and young adults had significantly increased oral microbiome diversity compared with all HSCT recipients (P < .001). The addition of xylitol to standard oral care significantly improves oral health, decreases BSI from oral organisms, and decreases the abundance of pathogenic oral organisms in pediatric and young adult HSCT recipients.

Conjugates of Ciprofloxacin and Levofloxacin with Cell-Penetrating Peptide Exhibit Antifungal Activity and Mammalian Cytotoxicity

Seven conjugates composed of well-known fluoroquinolone antibacterial agents, ciprofloxacin (CIP) or levofloxacin (LVX), and a cell-penetrating peptide transportan 10 (TP10-NH₂) were synthesised. The drugs were covalently bound to the peptide via an amide bond, methylenecarbonyl moiety, or a disulfide bridge. Conjugation of fluoroquinolones to TP10-NH₂ resulted in congeners demonstrating antifungal in vitro activity against human pathogenic yeasts of the Candida genus (MICs in the 6.25–100 µM range), whereas the components were poorly active. The antibacterial in vitro activity of most of the conjugates was lower than the activity of CIP or LVX, but the antibacterial effect of CIP-S-S-TP10-NH₂ was similar to the mother fluoroquinolone. Additionally, for two representative CIP and LVX conjugates, a rapid bactericidal effect was shown. Compared to fluoroquinolones, TP10-NH₂ and the majority of its conjugates generated a relatively low level of reactive oxygen species (ROS) in human embryonic kidney cells (HEK293) and human myeloid leukemia cells (HL-60). The conjugates exhibited cytotoxicity against three cell lines, HEK293, HepG2 (human liver cancer cell line), and LLC-PK1 (old male pig kidney cells), with IC₅₀ values in the 10–100 µM range and hemolytic activity. The mammalian toxicity was due to the intrinsic cytoplasmic membrane disruption activity of TP10-NH₂ since fluoroquinolones themselves were not cytotoxic. Nevertheless, the selectivity index values of the conjugates, both for the bacteria and human pathogenic yeasts, remained favourable.

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.

Make Sure You Have a Safety Net: Updates in the Prevention and Management of Infectious Complications in Stem Cell Transplant Recipients

Hematopoietic stem cell transplant recipients are at increased risk of infection and immune dysregulation due to reception of cytotoxic chemotherapy; development of graft versus host disease, which necessitates treatment with immunosuppressive medications; and placement of invasive catheters. The prevention and management of infections in these vulnerable hosts is of utmost importance and a key “safety net” in stem cell transplantation. In this review, we provide updates on the prevention and management of CMV infection; invasive fungal infections; bacterial infections; Clostridium difficile infection; and EBV, HHV-6, adenovirus and BK infections. We discuss novel drugs, such as letermovir, isavuconazole, meropenem-vaborbactam and bezlotoxumab; weigh the pros and cons of using fluoroquinolone prophylaxis during neutropenia after stem cell transplantation; and provide updates on important viral infections after hematopoietic stem cell transplant (HSCT). Optimizing the prevention and management of infectious diseases by using the best available evidence will contribute to better outcomes for stem cell transplant recipients, and provide the best possible “safety net” for these immunocompromised hosts.

Bacteremia in pediatric patients with hematopoietic stem cell transplantation

BACKGROUND

This study aimed to describe the incidence, microbiological profile, and risk factors associated with bacteremia in pediatric patients with hematopoietic stem cell transplantation (HSCT).

METHODS

A retrospective cohort study was performed on patients under 18 years old who underwent HSCT due to any indication, between January 2012 and January 2017. The patient data were collected from the first 100 days post-HSCT. Bacteremia was defined as the isolation of bacteria from at least one blood culture. The relation between bacteremia and associated risk factors was evaluated using univariate and multivariate analysis.

RESULTS

We enrolled a total of 111 pediatric patients who received HSCT during the period of study. The total number of patients who developed at least one episode of bacteremia was 46 (41.4%), and the total number of bacteremia episodes was 62. Rectal swabs were performed in 44 patients to detect prior colonization and this showed that 25% of them were positive, the main pathogen isolated being carbapenem-resistant enterobacteriaceae. The Gram-negative bacteria cases accounted for 60% of 62 events. The main Gram-negative bacteria isolated were Klebsiella pneumoniae and Escherichia coli and the majority were resistant strains. The mortality rate on day +100 for the whole cohort was 18% (n=20). Regarding the patients with bacteremia, the mortality rate on day +100 was 30% (n=14), and the cause of death was related to infection in 10 of them. We did not find any statistically significant risk factor for the development of bacteremia.

CONCLUSION

Bacteremia is common after HSCT, and there is a high frequency of resistant Gram-negative infections which is related to high mortality.

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.

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.

Fluoroquinolone Prophylaxis Is Highly Effective for the Prevention of Central Line-Associated Bloodstream Infections in Autologous Stem Cell Transplant Patients

Patients undergoing stem cell transplant (SCT) for the treatment of hematologic malignancy are at increased risk for central line-associated bloodstream infections (CLABSIs). The use of prophylactic antibiotics to prevent CLABSIs in the setting of autologous SCT is of unclear benefit. We aimed to evaluate the impact of levofloxacin prophylaxis on reducing CLABSIs in this high-risk population. Patients undergoing autologous SCT at a tertiary care hospital received levofloxacin prophylaxis from January 13, 2016 to January 12, 2017. Levofloxacin was administered from autologous SCT (day 0) until day 13, absolute neutrophil count > 500/mm³, or neutropenic fever, whichever occurred first. Clinical outcomes were compared with a baseline group who underwent autologous SCT but did not receive antibacterial prophylaxis during the previous year. The primary endpoint was incidence of CLABSIs assessed using Cox proportional hazards regression. A total of 324 patients underwent autologous SCT during the entire study period, with 150 receiving levofloxacin prophylaxis during the intervention period. The rate of CLABSIs was reduced from 18.4% during the baseline period to 6.0% during the intervention period. On multivariable analysis levofloxacin prophylaxis significantly reduced CLABSI incidence (hazard ratio, .33; 95% confidence interval [CI], .16 to .69; P = .003). There was also a reduction in the risk of neutropenic fever (odds ratio [OR], .23; 95% CI, .14 to .39; P < .001) and a trend toward a reduction in intensive care unit transfer for sepsis (OR, .33; 95% CI, .09 to 1.24; P = .10) in patients receiving levofloxacin prophylaxis. Notably, there was no increase in Clostridium difficile infection in the levofloxacin group (OR, .66; 95% CI, .29 to 1.49; P = .32). Levofloxacin prophylaxis was effective in reducing CLABSIs and neutropenic fever in patients undergoing autologous SCT. Further studies are needed to identify specific patient groups who will benefit most from antibiotic prophylaxis.