Prevalence of Resistant Gram-Negative Bacilli in Bloodstream Infection in Febrile Neutropenia Patients Undergoing Hematopoietic Stem Cell Transplantation: A Single Center Retrospective Cohort Study

Early bacteremia following allogeneic hematopoietic stem cell transplantation without antibiotic prophylaxis: epidemiology and antimicrobial resistance

OBJECTIVE

Bacteremia is a serious complication in patients undergoing allogeneic hematopoietic stem cell transplantation. The aim of this study was to determine the frequency, epidemiological profile, and risk factors of bacteremia early after allogeneic hematopoietic stem cell transplantation.

METHODS

An observational descriptive retrospective study was conducted in patients who received transplants between January 2016 and December 2021. Early bacteremia was defined as blood stream infection occurring between Day 0 and Day 100 after transplantation.

RESULTS

Forty episodes of early bacteremia occurred in 36/245 transplanted patients. Fifteen episodes (37.5%) were due to gram-positive bacteria and 25 (62.5%) to gram-negative bacteria. The most frequent species isolated were coagulase negative staphylococci (CoNS) in gram-positive bacteremia (n = 8/15), and Klebsiella species (8/25) and Pseudomonas species (8/25) in gram-negative bacteremia. Twenty-nine episodes of bacteremia (72.5%) occurred during the first 30 days after transplantation with a median time of nine days (range: 0-90 days). Coagulase negative staphylococci were methicillin-resistant in 75% of cases, the only Staphylococcus aureus isolated was methicillin-resistant. All gram-positive bacilli were penicillin-resistant. Gram-negative bacilli were multidrug resistant in 61.5% of cases. In multivariate analysis, bone marrow as source of graft (p-value = 0.02) and cytomegalovirus reactivation (p-value = 0.02) were significantly associated with an increased risk of bacteremia. Mortality attributable to bacteremia was 2.8%. The one-year overall survival was not significantly different between those with and without bacteremia.

CONCLUSIONS

Bacteremia was more frequent within the first 30 days after transplantation indicating the crucial role of neutropenia. An increase in multidrug resistant gram-negative bacteremia was noted.

Addressing the surge of infections by multidrug-resistant Enterobacterales in hematopoietic cell transplantation

Patients undergoing hematopoietic cell transplantation (HCT) have an increased risk of developing severe infections. In recent years, bloodstream infections caused by Gram-negative bacteria have been increasingly reported among HCT recipients, and many of these infections are caused by bacterial strains of the Enterobacterales order. Among these pathogens, particularly concerning are the multidrug-resistant Enterobacterales (MDRE), such as Extended Spectrum β-lactamase-producing Enterobacterales and Carbapenem-resistant Enterobacterales, since infections caused by these pathogens are difficult to treat due to the limited antimicrobial options and are associated with worse transplant outcomes. We summarized the evidence from studies published in PubMed and Scopus on the burden of MDRE infections in HCT recipients, and strategies for the management and prevention of these infections, including strict adherence to recommended infection control practices and multidisciplinary antimicrobial stewardship, the use of probiotics, and fecal microbiota transplantation, are also discussed.

Systematic review on epidemiology of Escherichia coli in bloodstream infection of patients undergoing hematopoietic stem cell transplantation

Introduction

We aimed to conduct a systematic review of the epidemiology of Escherichia coli in bloodstream infections (BSI) of hematopoietic stem cell transplantation patients.

Methods

For a comprehensive search of studies that reported the prevalence of E. coli and antibiotic resistance in bloodstream infections from 2000 to January 1, 2024, databases such as PubMed, EMBASE, Google Scholar, Scopus, and Web of Science were searched. The main keywords used were: Escherichia coli, epidemiology, bloodstream infection, microbial resistance, antibiotic resistance, hematopoietic malignancy, hematopoietic stem cell transplantation. After applying eligibility criteria, and quality assessment of studies, data analysis was done by comprehensive meta-analysis (CMA) software.

Results

The prevalence of bacterial bloodstream infections amongst different studies varied between 8-51%. Also, bloodstream infections caused by E. coli varied between 2.5-57%. Prevalence of extended-spectrum β-lactamases (ESBLs) of Escherichia coli in bloodstream infections varied between 15-80%. As well, the mortality rate caused by Escherichia coli strains in bloodstream infection varied between 6.7-27.3%. Resistance to ciprofloxacin, cefepime, third- and fourth-generation cephalosporins, was reported to be the highest (prevalence of 100%), and the lowest was against amikacin, with a prevalence between 13-38%.

Conclusions

The high prevalence of Escherichia coli-related BSI, and subsequent mortality, especially by multidrug resistance and ESBL strains, in patients undergoing hematopoietic stem cell transplantation, requires essential measures to prevent the spread of microbial resistance.

An Emergent Change in Epidemiologic and Microbiological Characteristics of Bloodstream Infections in Adults With Febrile Neutropenia Resulting From Chemotherapy for Acute Leukemia and Lymphoma at Reference Centers in Chile, Ecuador, and Peru

Background

Febrile neutropenia is a life-threatening condition commonly observed in patients with hematologic malignancies. The aim of this article is to provide updated knowledge about bloodstream infections in febrile neutropenia episodes within the Andean region of Latin America.

Method

This retrospective study was based in 6 hospitals in Chile, Ecuador, and Peru and included adult patients with acute leukemia or lymphoma and febrile neutropenia between January 2019 and December 2020.

Results

Of the 416 febrile neutropenia episodes, 38.7% had a bloodstream infection, 86% of which were caused by gram-negative rods, with Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa being the most frequently identified bacteria. K pneumoniae isolates were more frequently resistant than E coli to cefotaxime (65% vs 39.6%), piperacillin-tazobactam (56.7% vs 27.1%), and imipenem (35% vs 2.1%) and were more frequently multidrug resistant (61.7% vs 12.5%). Among P aeruginosa, 26.7% were resistant to ceftazidime, piperacillin-tazobactam, and imipenem, and 23.3% were multidrug resistant. Overall 30-day mortality was 19.8%, being higher with vs without a bloodstream infection (26.7% vs 15.3%, P = .005). Fever duration was also significantly longer, as well as periods of neutropenia and length of hospital stay for patients with bloodstream infection. Additionally, the 30-day mortality rate was higher for episodes with inappropriate vs appropriate empirical antibiotic therapy (41.2% vs 26.6%, P = .139).

Conclusions

Considering the high rates of bacteria-resistant infection and 30-day mortality, it is imperative to establish strategies that reduce the frequency of bloodstream infections, increasing early identification of patients at higher risks of multidrug bacteria resistance, and updating existing empirical antibiotic recommendations.

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.

Dissecting bloodstream infections in febrile neutropenic patients with hematological malignancies, a decade-long single center retrospective observational study (2009-2019)

BACKGROUND

The use of ill-suited antibiotics is a significant risk factor behind the increase in the mortality, morbidity, and economic burden for patients who are under treatment for hematological malignancy (HM) and bloodstream infections (BSI). Such unfitting treatment choices intensify the evolution of resistant variants which is a public health concern due to possible healthcare-associated infection spread to the general population. Hence, this study aims to evaluate antibiograms of patients with BSI and risk factors associated with septicemia.

METHODS

A total of 1166 febrile neutropenia episodes (FNE) among 513 patients with HM from the National Center for Cancer Care and Research (NCCCR), Qatar, during 2009-2019 were used for this study. The socio-demographic, clinical, microbial, and anti-microbial data retrieved from the patient's health records were used.

RESULTS

We analyzed the sensitivity of gram-negative and gram-positive bacilli reported in HM-FN-BSI patients. Out of the total 512 microorganisms isolated, 416 (81%) were gram-negative bacteria (GNB), 76 (15%) were gram-positive bacteria (GPB) and 20 (4%) were fungi. Furthermore, in 416 GNB, 298 (71.6%) were Enterobacteriaceae sp. among which 121 (41%) were ESBL (Extended Spectrum Beta-Lactamase) resistant to Cephalosporine third generation and Piperacillin-Tazobactam, 54 (18%) were Carbapenem-resistant or multidrug-resistant organism (MDRO). It's noteworthy that the predominant infectious agents in our hospital include E. coli, Klebsiella species, and P. aeruginosa. Throughout the study period, the mortality rate due to BSI was 23%. Risk factors that show a significant correlation with death are age, disease status, mono or polymicrobial BSI and septic shock.

CONCLUSION

Decision pertaining to the usage of antimicrobials for HM-FN-BSI patients is a critical task that relies on the latest pattern of prevalence, treatment resistance, and clinical outcomes. Analysis of the antibiogram of HM-FN-BSI patients in Qatar calls for a reconsideration of currently followed empirical antibiotic therapy towards better infection control and antimicrobial stewardship.

Hematopoietic stem-cell transplantation in a zoo of multidrug-resistant organisms: Data from a cancer center in eastern India

BACKGROUND

Infections by multidrug-resistant organisms (MDRO) are a major hurdle in hematopoietic stem-cell transplants (HSCTs). Conditioning regimens lead to mucosal barrier injury, which in-turn leads to transmigration of gut bacteria and sepsis. Pre-transplant stool and throat surveillance cultures can guide empirical antibiotic policy during the neutropenic period. In this paper, we document colonization with MDRO in pre-transplant surveillance cultures and the correlation with bloodstream infections in HSCT patients and analyze transplant outcomes with respect to these infections.

METHODS

A single-center, retrospective study on HSCT was performed between January 2021 and December 2021. The incidence of bacterial infections, percentage of MDROs, correlation with pre-transplant stool/throat surveillance cultures, and their impact on overall 100-day and post-100-day to 6-month post-transplant survival were analyzed.

RESULTS

Sixty-four patients were included in the study. Pre-transplant stool surveillance cultures were positive for MDRO in 85.9% of patients. Almost half (48.5%) of the isolates were positive for carbapenemase-producing genes (mainly New Delhi metallo-beta-lactamase-1 [NDM-1] and oxacillinase-48 [OXA-48]). Eighteen patients (18/64, 28%) had a positive blood culture for MDRO in the peri-engraftment neutropenic period. Correlation between surveillance and blood cultures was seen in 61% (11/18) of patients. All-cause mortality was 14.1% (9/64) and 25% (16/64) in patients at 100 days and 6 months post-HSCT, respectively. The 100-day and post-100-day all-cause mortality rates were higher in patients with Gram-negative MDRO bloodstream infections (p < .012 and <.008, respectively).

CONCLUSION

MDRO infections can adversely affect HSCT outcomes. Pre-transplant stool and throat surveillance cultures may guide empirical antibiotic policy and lead to favorable transplant outcomes.

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

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

Prevalence and Outcomes of Carbapenem-resistant Bloodstream Infection in Children With Cancer

INTRODUCTION

Carbapenem-resistant (CR) infections cause major morbidity and mortality. Data on CR infections in children with cancer are scarce, especially from the developing world. The aim of this study was to evaluate the characteristics and outcomes of bacteremia with CR organisms (CRO) compared with bacteremia with Carbapenem-sensitive organisms in children with cancer.

METHODS

This retrospective observational study was conducted in a tertiary pediatric oncology center in South India. Data on all bloodstream infections with Gram-negative organisms (CRO and Carbapenem sensitive-organisms) in children with malignancy ≤14 years of age from August 2017 to July 2021 were retrieved. The outcome was determined as survival and all-cause death 28 days after the date of Bloodstream infection (BSI) onset.

RESULTS

Sixty-four Gram-negative BSI were identified, with 24% (n=15) in the Carbapenem-Resistant Bloodstream Infection (CR-BSI) group and 76% (n=49) in the Carbapenem-sensitive-Bloodstream Infection group. The patients included 35 males (64%) and 20 females (36%), with ages ranging from 1 year to 14 years (median age: 6.2 y). The most common underlying disease was hematologic malignancy (92.2%, n=59). Children with CR-BSI had a higher incidence of prolonged neutropenia, septic shock, pneumoniae, enterocolitis, altered consciousness, and acute renal failure and were associated with 28-day mortality in univariate analysis. The most common carbapenem-resistant Gram-negative bacilli isolates were Klebsiella species (47%) and Escherichia coli (33%). All carbapenem-resistant isolates were sensitive to colistin, and 33% were sensitive to Tigecycline. The case-fatality rate was 14% (9/64) in our cohort. The overall 28 days mortality was significantly higher in patients with CR-BSI than in those with Carbapenem-sensitive Bloodstream Infection (28-day mortality: 43.8% vs. 4.2%, P =0.001).

CONCLUSIONS

Bacteremia with CRO has higher mortality in children with cancer. Prolonged neutropenia, pneumoniae, septic shock, enterocolitis, acute renal failure, and altered consciousness were predictors of 28-day mortality in carbapenem-resistant septicemia.

Clinical Characteristics and Prognosis of Bloodstream Infection with Carbapenem-Resistant Pseudomonas aeruginosa in Patients with Hematologic Malignancies

Objective

To analyze the clinical characteristics and prognostic risk factors of carbapenem-resistant Pseudomonas aeruginosa (CRPA) bloodstream infections in patients with hematologic malignancies.

Methods

Medical records and drug susceptibility data of patients with hematologic malignancies complicated by CRPA bloodstream infections admitted to the Cancer Hospital of Zhengzhou University between January 1, 2018, and December 31, 2022, were retrospectively analyzed.

Results

A total of 64 patients were included in the study, with a mortality rate of 37.5% (24/64) at 28 days after the occurrence of CRPA bloodstream infection. In Cox regression analysis, an absolute neutrophil count <0.5×109/L at discharge (HR 0.039, 95% CI 0.006 ~ 0.258, p=0.001), admission to the intensive care unit (HR 7.546, 95% CI 1.345 ~ 42.338, p= 0.022), and a higher Pitt bacteremia score (HR 0.207, 95% CI 0.046 ~ 0.939, p = 0.041) were independent risk factors associated with 28-day mortality. Survival analysis showed that patients receiving ceftazidime-avibactam-based (HR 0.368, 95% CI 0.107~ 1.268, p = 0.023) or polymyxin B (HR 2.561, 95% CI 0.721 ~ 9.101, p = 0.015) therapy had a higher survival rate.

Conclusion

Patients with hematologic neoplasms had high mortality from CRPA bloodstream infections, and admission to the intensive care unit, higher Pitt bacteremia score (PBS) scores, granulocyte deficiency, and granulocyte deficiency at discharge were independently associated with higher mortality. Early anti-infective treatment with ceftazidime-avibactam or polymyxin B may improve the clinical prognosis of patients.

Bloodstream infections due to Carbapenem-Resistant Enterobacteriaceae in hematological patients: assessment of risk factors for mortality and treatment options

PURPOSE

Bloodstream infection (BSI) caused by Carbapenem-Resistant Enterobacteriaceae (CRE) are associated with poor outcomes in hematological patients. The aim of this study was to identify risk factors for mortality and evaluate the value of epidemiological feature of carbapenemases in guiding antimicrobial treatment options.

METHODS

Hematological patients with monomicrobial CRE BSI between January 2012 and April 2021 were included. The primary outcome was all-cause mortality 30 days after BSI onset.

RESULTS

A total of 94 patients were documented in the study period. Escherichia coli was the most common Enterobacteriaceae, followed by Klebsiella pneumoniae. 66 CRE strains were tested for carbapenemase genes, and 81.8% (54/66) were positive, including NDM (36/54), KPC (16/54), IMP (1/54). Besides, one E. coli isolate was found to express both NDM and OXA-48-like genes. Overall, 28 patients received an antimicrobial treatment containing ceftazidime-avibactam (CAZ-AVI), of which 21 cases were combined with aztreonam. The remaining 66 patients were treated with other active antibiotics (OAAs). The 30-day mortality rate was 28.7% (27/94) for all patients, and was only 7.1% ((2/28) for patients treated with CAZ-AVI. In multivariate analysis, the presence of septic shock at BSI onset (OR 10.526, 95% CI 1.376-76.923) and pulmonary infection (OR 6.289, 95% CI 1.351-29.412) were independently risk factors for 30-day mortality. Comparing different antimicrobial regimens, CAZ-AVI showed a significant survive benefit than OAAs (OR 0.068, 95% CI 0.007-0.651).

CONCLUSION

CAZ-AVI-containing regimen is superior to OAAs for CRE BSI. As the predominance of blaNDM in our center, we recommend the combination with aztreonam when choose CAZ-AVI.

Epidemiology, drug resistance analysis and mortality risk factor prediction of gram-negative bacteria infections in patients with allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment for many malignant and refractory diseases. However, infections, as the most common complication after transplantation, often lead to poor long-term prognosis of patients. In this study, we collected electronic medical records of allo-HSCT recipients with gram-negative bacteria (GNB) infections between January 2012 and September 2021, analyzed epidemiological characteristics and antibiotic sensitivity, and determined independent risk factors for carbapenem-resistant GNB (CR-GNB) infections and death by Logistic and Cox regression models. During the 9-year period, 183 of 968 patients developed GNB infections, of which 58 died. The most common pathogen was Klebsiella pneumoniae. CR-GNB, especially carbapenem-resistant Klebsiella pneumonia (CRKP), carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenem-resistant Escherichia coli (CREC) had a high resistance rate to commonly used clinical antibiotics. Independent risk factors for CR-GNB infections were use of carbapenem antibiotics for >3 days one month before transplantation (OR = 3.244, 95% CI 1.428-7.369, P = 0.005), use of special immunosuppressants after transplantation (OR = 1.21, 95% CI 1.008-1.452, P = 0.041), and time of hematopoietic reconstruction >20 days (OR = 2.628, 95% CI 1.369-5.043, P = 0.004). Independent risk factors for mortality were interval between diagnosis and transplantation >180 days (HR = 2.039, 95% CI 1.05 to 3.963, P = 0.035), total bilirubin levels during infection >34.2 μmol/L (HR = 3.39, 95% CI 1.583-7.256, P = 0.002) and septic shock (HR = 5.345, 95% CI 2.655-10.761, P = 0.000). In conclusion, GNB has a high incidence and mortality in allo-HSCT recipients. Early transplantation for eligible patients, attention to liver function protection, timely identification and treatment of septic shock can help to improve the prognosis of patients.

Impact of Adding a Rapid PCR-Based Blood Culture Identification Panel to the Antimicrobial Stewardship Program of Patients with Febrile Neutropenia in a Peruvian Referral Hospital

The addition of Biofire^® FilmArray^® Blood Culture Identification panel 2 (BCID2) to the antimicrobial stewardship program (ASP) could improve outcomes in bloodstream infections (BSI) of patients with febrile neutropenia (FN). A pre- and post-quasi-experimental single-center study was conducted at a reference hospital in Peru. Three groups were considered: patients with BSI before ASP intervention (control group), patients with BSI after ASP intervention (group 1), and patients with BSI after ASP intervention plus BCID2 PCR Panel implementation (group 2). Overall, 93 patients were identified (32 control, 30 group 1, 31 group 2). The median time to effective therapy was significantly shorter in group 2 compared to group 1 and control group, respectively (3.75 vs. 10 h, p = 0.004; 3.75 vs. 19 h, p < 0.001). No significant differences in terms of relapse of bacteremia, in-hospital mortality (all cause), and 30-day-all-cause hospital readmission between the three study periods were found. The appropriateness of empirical antimicrobial use, adding or change, and the following de-escalation or discontinuation was significant when the two intervention periods were compared with the control group (p < 0.001). In addition to the lack of local studies documenting the microbiological profile of FN episodes, adding syndromic panels-based testing could allow for the consolidation of ASP strategies.

Development of a Risk Prediction Model of Subsequent Bloodstream Infection After Carbapenem-Resistant Enterobacteriaceae Isolated from Perianal Swabs in Hematological Patients

Purpose

Patients with hematological diseases are at high risk of carbapenem-resistant Enterobacteriaceae (CRE) infection, and CRE-related bloodstream infection (BSI) is associated with high mortality risk. Therefore, developing a predictive risk model for subsequent BSI in hematological patients with CRE isolated from perianal swabs could be used to guide preventive strategies.

Methods

This was a single-center retrospective cohort study at a tertiary blood diseases hospital, including all hematological patients hospitalized from 10 October 2017 to 31 July 2021. We developed a predictive model using multivariable logistic regression and internally validated it using enhanced bootstrap resampling.

Results

Of 421 included patients with CRE isolated from perianal swabs, BSI due to CRE occurred in 59. According to the multivariate logistic analysis, age (OR[odds ratio]=1.04, 95% CI[confidence interval]: 1.01-1.06, P=0.004), both meropenem and imipenem minimal inhibitory concentration (MIC) of the isolate from perianal swabs>8ug/mL (OR=5.34, 95% CI: 2.63-11.5, P<0.001), gastrointestinal symptoms (OR=3.67, 95% CI: 1.82-7.58, P<0.001), valley absolute neutrophil count (10⁹/L)>0.025 (OR=0.07, 95% CI: (0.02-0.19, P<0.001) and shaking chills at peak temperature (OR=6.94, 95% CI: (2.60-19.2, P<0.001) were independently associated with CRE BSI within 30 days and included in the prediction model. At a cut-off of prediction probability ≥ 21.5% the model exhibited a sensitivity, specificity, positive predictive value and negative predictive value of 79.7%, 85.6%, 96.27% and 47.47%. The discrimination and calibration of the prediction model were good on the derivation data (C-statistics=0.8898; Brier score=0.079) and enhanced bootstrapped validation dataset (adjusted C-statistics=0.881; adjusted Brier score=0.083). The risk prediction model is freely available as a mobile application at https://liujia1992.shinyapps.io/dynnomapp/.

Conclusion

A prediction model based on age, meropenem and imipenem MIC of isolate, gastrointestinal symptoms, valley absolute neutrophil count and shaking chills may be used to better inform interventions in hematological patients with CRE isolated from perianal swabs.

Risk Factors for Mortality and Outcomes in Hematological Malignancy Patients with Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infections

Background

This study aimed to identify risk factors for mortality and outcomes in hematological malignancy (HM) patients with bloodstream infection (BSI) caused by carbapenem-resistant Klebsiella pneumoniae (CRKP).

Methods

A retrospective study was conducted at a tertiary teaching hospital in Henan Province, China, between January 2018 and December 2021. All BSIs caused by CRKP in hospitalized HM patients were identified. Data on patient demographics, disease, laboratory tests, treatment regimens, outcomes of infection, and the antimicrobial susceptibility of each isolate were collected from medical records.

Results

A total of 129 patients with CRKP BSI were included in the study, and the 28-day mortality rate was 80.6% (104/129). In Cox analysis an absolute neutrophil count < 500 at discharge (hazard ratio [HR] 6.386, 95% confidence interval [CI] 3.074–13.266, p < 0.001), intensive care unit admission (HR 1.834, 95% CI 1.065–3.157, p = 0.029), and higher Pitt bacteremia score (HR 1.185, 95% CI 1.118–1.255, p < 0.001) were independent risk factors associated with 28-day mortality. Survival curve analysis indicated that compared with ceftazidime-avibactam-based therapy, both polymyxin b (HR 8.175, 95% CI 1.099–60.804, p = 0.040) and tigecycline (HR 14.527, 95% CI 2.000–105.541, p =0.008) were associated with a higher risk of mortality.

Conclusion

In HM patients CRKP BSI resulted in high mortality. Intensive care unit admission, higher Pitt bacteremia score, and absolute neutrophil count < 500 at discharge were independently associated with higher mortality. Early initiation of new agents such as ceftazidime-avibactam may improve outcomes.

Pseudomonas aeruginosa Pneumonia: Evolution of Antimicrobial Resistance and Implications for Therapy

Pseudomonas aeruginosa (PA), a non-lactose-fermenting gram-negative bacillus, is a common cause of nosocomial infections in critically ill or debilitated patients, particularly ventilator-associated pneumonia (VAP), and infections of urinary tract, intra-abdominal, wounds, skin/soft tissue, and bloodstream. PA rarely affects healthy individuals, but may cause serious infections in patients with chronic structural lung disease, comorbidities, advanced age, impaired immune defenses, or with medical devices (e.g., urinary or intravascular catheters, foreign bodies). Treatment of pseudomonal infections is difficult, as PA is intrinsically resistant to multiple antimicrobials, and may acquire new resistance determinants even while on antimicrobial therapy. Mortality associated with pseudomonal VAP or bacteremias is high (> 35%) and optimal therapy is controversial. Over the past three decades, antimicrobial resistance (AMR) among PA has escalated globally, via dissemination of several international multidrug resistant "epidemic" clones. We discuss the importance of PA as a cause of pneumonia including health care-associated pneumonia, hospital-acquired pneumonia, VAP, the emergence of AMR to this pathogen, and approaches to therapy (both empirical and definitive).

Surveillance Stool Culture and its Association with Microbiologically Documented Infection During Febrile Neutropenia in Patients with Acute Leukemia (AL) Undergoing Induction Chemotherapy

The study aimed at identifying the profile of gut colonization of patients with acute leukemia who underwent induction chemotherapy and its association with induction events and outcome. Baseline bacterial stool culture with resistance pattern of isolates were recorded. Multi-drug resistance was defined as resistance to at least two antibiotic classes including beta lactam and fluoroquinolones. During induction chemotherapy, blood and clinically indicated cultures were taken during febrile neutropenic episodes. Association studies were done between gut colonization and induction events/outcome. Among 109 patients enrolled, 71 (65.13%) patients undergoing induction chemotherapy were colonized with bacteria, with nearly 50% of colonizers harboring multi-drug resistant bacteria. Organisms isolated from stool pre-induction were mostly gram negative (98%), with Escherichia coli and Klebsiella pneumoniae being the commonest. 65.13% patients developed febrile neutropenia. Overall multi-drug resistant positivity during febrile neutropenia was 70.14%. Concordance of 8.45% was observed between isolates from stool and organisms isolated from cultures during febrile neutropenia. There were significant proportion of gut colonized gram-negative multi-drug resistance bacteria among patients with acute leukemia. There was a low concordance rate between baseline stool isolates and subsequent cultures during the induction. There was no significant association between gut colonization and induction events/outcomes studied.

Clinical outcome from hematopoietic cell transplant patients with bloodstream infection caused by carbapenem-resistant P. aeruginosa and the impact of antimicrobial combination in vitro

Bloodstream infection (BSI) caused by carbapenem-resistant P. aeruginosa (CRPA) has high mortality in hematopoietic stem cell transplant (HSCT) recipients. We performed MIC, checkerboard, time-kill assay, PFGE, PCR, and whole genome sequence and described the clinical outcome through Epi Info comparing the antimicrobial combination in vitro. Mortality was higher in BSI caused by CRPA carrying the lasB virulence gene. The isolates were 97% resistant to meropenem displaying synergistic effect to 57% in combination with colistin. Seventy-three percent of the isolates harbored bla_SPM-1 and Tn4371 and belonged to ST277. The synergistic effect in vitro with meropenem with colistin appeared to be a better therapeutic option.

Bloodstream Infections and Outcomes Following Allogeneic Hematopoietic Cell Transplantation: A Single-Center Study

This study investigated the single-center incidence and risk factors for bloodstream infections (BSIs) in 651 adults who underwent allogeneic hematopoietic cell transplantation (alloHCT) between 2015 and 2019 and explored the impact of these BSIs on post-transplantation outcomes. Antibiotic prophylaxis with ciprofloxacin was given during the aplastic phase. Overall, the median patient age was 57 years, 79.7% of patients received an alternative donor graft, and 68.7% received post-transplantation cyclophosphamide (PTCy) as part of their graft-versus-host disease (GVHD) prophylaxis. Of the 651 patients, 358 (55.0%) had at least 1 episode of BSI, and the overall mortality rate secondary to this complication was 7.5% (12.6% among those diagnosed with at least 1 episode of BSI). BSI was more often diagnosed during the first 30 days (58.7%), and gram-positive bacteria were the most prevalent microorganisms isolated during the entire post-transplantation follow-up (62%). A high Disease Risk Index (hazard ratio [HR], 1.47; P < .029) and receipt of PTCy-based GVHD prophylaxis (HR, 3.33; P < .001) were identified as risk factors for BSI. Additionally, univariate analysis showed that patients diagnosed with a BSI during post-transplantation follow-up had worse overall survival (HR, 2.48; P < .001) and higher nonrelapse mortality (HR, 2.68; P < .001) than those without BSI. In conclusion, alloHCT recipients with a BSI had a higher risk of mortality compared with those who did not develop BSI. The inclusion of PTCy as part of GVHD prophylaxis was identified as an independent risk factor for BSI during early post-transplantation follow-up. Single-center analyses focused on reporting the incidence and risk factors for BSI highlight the need for active implementation of preemptive strategies to decrease BSI incidence in the alloHCT setting. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

[Analysing pathogenic bacterial spectrum and drug resistance of bloodstream infection in patients with allogeneic hematopoietic stem cell transplantation]

Objective: To elucidate the clinical characteristics of bloodstream infection in patients with allogeneic hematopoietic stem cell transplantation (allo-HSCT) in our hospital and improves the survival of transplant patients with bloodstream infection. Methods: Two hundred and ten patients with allo-HSCT from the Department of Hematology were retrospectively analyzed between October 2014 and September 2019. Pathogen distribution, drug resistance, risk factors, and outcomes were investigated in 49 allo-HSCT patients with bloodstream infections. Results: Forty-nine of 210 patients with allo-HSCT had bloodstream infection, and 59 pathogenic microorganisms were identified, mainly Gram-negative bacteria (67.8%) , of which E. coli had the highest incidence (23.7%) , CRO accounted for 42.5%, and Grampositive bacteria accounted for 23.7% (without vancomycin or linezolid-resistant strain) . Additionally, fungi accounted for 8.5%. Univariate analysis suggested that the risk factors of bloodstream infection were gender, pretransplant disease status, and conditioning regimen. In contrast, multivariate analysis showed that bloodstream infection was mainly related to conditioning regimens. Further grouping results showed that 77.6% of patients with neutropenia had bloodstream infections, and 22.4% of patients with non-neutropenia had bloodstream infections; 81.0% of patients with active infections before transplantation had bloodstream infections, while bloodstream infection occurred in 16.9% of patients without active infection. Survival analysis showed that long-term survival of patients with bloodstream infection is shorter than that of patients without bloodstream infection and long-term survival of patients with CRO infection is shorter than that of patients without CRO infection. The survival of patients with neutropenia longer than 14 d is shorter than that of patients with neutropenia shorter than 14 d. Furthermore, there is no correlation between whether there is an active infection before transplantation and whether they are in a neutropenic state at the time of infection and survival. Conclusion: Our results suggest that effective prevention of bloodstream infections from drug-resistant bacteria, particularly CRO, shortening the duration of neutropenia, eradication of potential infections before transplantation, and patient-adaptive conditioning could reduce transplant-related mortality and improve prognosis.

A practical update on the epidemiology and risk factors for the emergence and mortality of bloodstream infections from real-world data of 3014 hematological malignancy patients receiving chemotherapy

Background: Bloodstream infection (BSI) is a common and serious complication after patients with hematologic malignancies (HM) receiving chemotherapy. This study examined real-world data seeking to characterize HM BSI and identify risk factors for BSI emergence and mortality.

Methods: We retrospectively analyzed the pathogenic epidemiology, antibiotic resistance, and BSI risk factors in a single-center cohort including 3014 consecutive patients with HM receiving chemotherapy between 2013 and 2016. Results of the pathogenic epidemiology were validated via comparison to available reported data.

Results: We found that 725 patients (24.1%) had BSIs. Gram-negative (G-) bacteria represented 64.7% of the 744 isolated pathogenic strains, while Gram-positive (G+) bacteria and fungi accounted for 27.7% and 7.7% of the BSIs, respectively. The most common isolates were Klebsiella pneumoniae (19.2%), and 95.1% of the multidrug-resistant strains (MDR) were extended-spectrum beta-lactamase producing strains. G- bacteria were the main microflora responsible for BSI in our cohort of Chinese HM patients compared to studies in developed countries or in neutropenic children with HM or solid tumors. Multivariate analysis revealed that male sex, age ≥ 45 and < 65 yr, hospital length of stay ≥ 9d, neutropenia ≥ 7d before cultures, ≥ 2 antibiotics, and infections (gastrointestinal, perirectal, or urinary tract) independently predicted BSI emergence. Furthermore, age ≥ 65 yr, neutropenia ≥ 7d before blood cultures, no HM remission, lower white blood cell count, ≥ 3 antibiotics, respiratory infections, and Acinetobacter baumannii and Stenotrophomonas maltophilia BSI were independent predictors of 30-day mortality.

Conclusions: G- bacteria were the predominant microflora during the study period and antibiotic resistance levels of the pathogens detected were high, especially for MDR strains. The mortality of BSI patients was high in this large cohort. Close attention should be paid to the risk factors identified here to facilitate timely and effective clinical management of such patients.

Septic Arthritis and Osteomyelitis Caused by Chryseobacterium indologenes in a Mute Swan (Cygnus olor) and a Ring-Billed Gull (Larus delawarensis)

A 20-year-old female mute swan (Cygnus olor) originally in a flock of free-living swans on a Long Island, New York, lake, was presented for facial swelling and decreased appetite. An adult male ring-billed gull (Larus delawarensis) was also presented to the same wildlife rescue center for bilateral lameness of 1-week duration. Once referred for veterinary evaluation and care, both species were diagnosed with septic arthritis and osteomyelitis caused by Chryseobacterium indologenes and treated with orbifloxacin until complete recovery. Chryseobacterium indologenes is infrequently diagnosed as an opportunistic pathogen in human medicine, and less so in veterinary medicine. In human patients, this bacterium is the cause of various infections, including meningitis, pneumonia, and implant failure. However, in veterinary medicine its pathogenicity has only been reported in fish, and sporadically mentioned as a culture result in tree frogs and turtles, where it was generally considered insignificant. In this report a clinical presentation, diagnosis, treatment, and outcome of osteomyelitis and septic arthritis caused by C indologenes is described in 1 anseriforme and in 1 charadriiforme species.

The Roles of γδ T Cells in Hematopoietic Stem Cell Transplantation

The αβ T-cell-depleted hematopoietic stem cell transplantation (HSCT) leads to lower relapse and better outcome, and may correlate strongly with expansion of donor-derived γδ T cells. γδ T cells play an important role in immune reconstitution and can exert a graft-versus-leukemia effect after HSCT. This review showed the recent literature on immune functions of γδ T cells after HSCT. The discrepancies between studies of γδ T cells in graft-versus-host disease may cause by its heterogeneous and various distinct subsets. And reconstitution of γδ T cells may play a potential immunoregulatory role in the infections after HSCT.

Carbapenem-Resistant Enterobacteriaceae-Implications for Treating Acute Leukemias, a Subgroup of Hematological Malignancies

Acute leukemias (AL) are a group of aggressive malignant diseases associated with a high degree of morbidity and mortality. Patients with AL are highly susceptible to infectious diseases due to the disease itself, factors attributed to treatment, and specific individual risk factors. Enterobacteriaceae presence (e.g., Klebsiella pneumonia and Escherichia coli) is a frequent cause of bloodstream infections in AL patients. Carbapenem-resistant Enterobacteriaceae (CRE) is an emerging health problem worldwide; however, the incidence of CRE varies greatly between different regions. Carbapenem resistance in Enterobacteriaceae is caused by different mechanisms, and CRE may display various resistance profiles. Bacterial co-expression of genes conferring resistance to both broad-spectrum β-lactam antibiotics (including carbapenems) and other classes of antibiotics may give rise to multidrug-resistant organisms (MDROs). The spread of CRE represents a major treatment challenge for clinicians due to lack of randomized clinical trials (RCTs), a limited number of antibiotics available, and the side-effects associated with them. Most research concerning CRE infections in AL patients are limited to case reports and retrospective reviews. Current research recommends treatment with older antibiotics, such as polymyxins, fosfomycin, older aminoglycosides, and in some cases carbapenems. To prevent the spread of resistant microbes, it is of pivotal interest to implement antibiotic stewardship to reduce broad-spectrum antibiotic treatment, but without giving too narrow a treatment to neutropenic infected patients.

D-index as a marker of bloodstream infections in patients with allogeneic hematopoietic stem cell transplantation

BACKGROUND

Neutropenia is a risk factor for development of infections; however, the direct effect of neutropenia on development of bloodstream infection (BSI) is not known. D-index, which is area between the neutrophil time curve and a neutrophil count of 0.5 × 10⁹ /L, incorporates the combined effect of severity and duration of neutropenia. We aimed to evaluate whether D-index can be used as a marker for BSI in patients with allogeneic stem cell transplantation.

METHOD

We conducted a retrospective cohort study of patients undergoing allogeneic stem cell transplantation between January 1, 2005, and September 30, 2015. The primary outcome measure was the development of BSI within 30 days of transplantation.

RESULTS

A total of 714 patients were included in the study of whom 101 developed BSI. Patients with BSI had a significantly higher median D-index value compared with patients who did not have BSI (4990 vs. 3570, P < .001). As a marker, the performance of the D-index was similar to that of the duration of profound neutropenia (P = .18) and significantly better than the total duration of neutropenia (P = .001).

CONCLUSION

The D-index performed better than the total duration of neutropenia as a marker for BSI in patients with allogeneic stem cell transplantation. There was no difference between D-index and, a more easily calculable indicator, duration of profound neutropenia.

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.

Treatment-Related Mortality From Infectious Complications in an Acute Leukemia Clinic

Background

The main causes of mortality in patients with acute leukemia are the infectious complications. The author wanted to know the induction-related mortality and treatment-related mortality in the acute leukemia patients at the Instituto Nacional de Cancerologia (INCan), Mexico. Also the author is interested in finding out the micro-organism and the main site of infection to make some changes in the management of patients in these clinics. Primary objective was induction chemotherapy-related mortality and treatment-related mortality. Secondary objective was to determine the site of infection, micro-organism, type of chemotherapy related with more mortality and relapse mortality.

Methods

This was a retrospective case-series analysis of all patients who were admitted to the INCan Acute Leukemia Clinic between January 2012 and December 2015 with febrile neutropenic complications. We reviewed the case histories of all patients, including those with acute lymphoblastic leukemia (ALL), acute myeloblastic leukemia (AML), acute biphenotypic leukemia and acute promyelocytic leukemia, regardless of disease status (newly diagnosed or relapsed) at the time of clinic attendance. Patients who died as the result of an infectious complication during the analysis window were identified, and their demographics, disease characteristics, treatment history (chemotherapy within 45 days of date of death) and details of the infectious complication resulting in death were collected.

Results

Of the 313 patients studied during that time period, 84 (27%) died as a result of infectious complications. Lung infections were the most common, accounting for 67% of all deaths from infectious complications. Escherichia coli producing extended-spectrum beta-lactamases was the most frequently isolated infectious organism (12 patients; 14%). The majority of deaths occurred during either induction therapy (27 patients; 32%) or treatment for a first relapse (25 patients; 30%). Hyperfractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone (hyper-CVAD) was the chemotherapy regimen most commonly received within 45 days prior to death (17 patients; 20%).

Conclusions

Our findings suggest a need for long-term management and supportive care to prevent infectious complication-associated fatalities during both initial chemotherapy and subsequent disease relapse in patients with acute leukemia. The use of prophylaxis will help patients to prevent complications.

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.

Infections Due to Carbapenem-Resistant Bacteria in Patients With Hematologic Malignancies

In developed countries, hematological malignancies (HM) account for 8 to 10% of cancers diagnosed annually and one-third of patients with HM (HMP) are expected to die from their disease. The former wide spectrum “magic bullet,” imipenem, has been ousted by the emergence of carbapenem resistant (CR) pathogens. In endemic areas, infections with CR-bacteria occur in vulnerable patients, notably in HMP, who suffer from high mortality related to infectious complications. In this work, we reviewed epidemiologic and clinical factors associated with CR-infections in adult HMP and data on CR-related mortality and antibiotic treatments in this population. We found that resistance profile of strains involved in HMP infections, mainly bacteremia, reflect local epidemiology. Significant risk factors for infections with CR-bacteria include sex male, age around 50 years old, acute leukemia, selvage chemotherapy, neutropenia, and digestive colonization by CR-bacteria. Mortality rate is high in HMP infected with CR-Enterobacteriaceae, more particularly in case of acute myeloid leukemia and unresolved neutropenia, due to inappropriate empiric management and delayed administration of targeted antibiotics, such as tigecycline, colistin, or new associations of active drugs. Thus, we developed an algorithm for clinicians, assessing the incremental risk for CR-bacterial infection occurrence and mortality in febrile HMP, to guide decisions related to empirical therapeutic strategies.

Cancer patients with neutropenic septic shock: etiology and antimicrobial resistance

BACKGROUND/AIMS

Among patients with febrile neutropenia that developed after chemotherapy, high-risk patients, such as those having clinical instability or Multinational Association of Supportive Care in Cancer score of < 21, require hospitalization for intravenous empiric antibiotic therapy. Monotherapy with an anti-pseudomonal ß-lactam agent is recommended. Although many studies reported the microbial etiology of infections and resistant patterns of febrile neutropenia, the patients were not well characterized as having neutropenic septic shock. Therefore, this study aimed to determine the microbial spectrum of infections and resistance patterns of their isolates in patients with chemotherapy-induced neutropenic septic shock.

METHODS

Data of adult patients diagnosed with neutropenic septic shock in the emergency department between June 2012 and December 2016 were extracted from a prospectively compiled septic shock registry at a single academic medical center. Thereafter, microbiological studies and antimicrobial susceptibility tests were conducted.

RESULTS

In total, 109 bacteria were found in patients with neutropenic septic shock. Gram-negative bacteria were the predominant causative organisms (84, 77.1%). Moreover, 33 microorganisms (30.3%) were multidrug-resistant (MDR) bacteria with extended-spectrum ß-lactamase-producing Escherichia coli (17, 50%) being the commonest. The most commonly affected sites in patients with MDR bacterial infections were the gastrointestinal tract (45%) and unknown (43.5%). Approximately 48.5% of MDR bacteria were resistant to cefepime but not to piperacillin-tazobactam or carbapenem.

CONCLUSION

MDR bacteria were prevalent in patients with chemotherapy-induced neutropenic septic shock. Therefore, piperacillin-tazobactam or carbapenem may be considered as empiric antibiotics if MDR bacteria are suspected to be causative agents.

Parotitis due to Burkholderia cepacia infection after autologous hematopoietic stem cell transplantation

Burkholderia cepacia predominantly causes opportunistic infections in hospitalized and immunocompromised patients such as patients with cystic fibrosis, cancer, or human immunodeficiency virus (HIV). Nonetheless, Burkholderia cepacia is infrequently reported to cause infection in hematopoietic stem cell transplantation (HSCT) recipients. Herein, we report a rare case of suppurative parotitis in a 31-year-old patient with T-cell lymphoblastic lymphoma (T-LBL) who underwent auto-HSCT. The secretion from the Stensen duct was collected, and Burkholderia cepacia was detected using the VITEK-2 identification system. Additionally, sensitive antibiotic therapy against this bacterium was also effective. This is the first case of parotitis triggered by Burkholderia cepacia after auto-HSCT, and it is also the first reported domestic case. This case emphasizes the importance of considering bacterial infections in general and Burkholderia cepacia specifically in HSCT patients with post-transplant parotitis.

Infectious Complications in Patients With Multiple Myeloma After High-Dose Chemotherapy Followed by Autologous Stem Cell Transplant: Nationwide Study of the Infectious Complications Study Group of the Polish Adult Leukemia Group

BACKGROUND

Multiple myeloma (MM) has become a chronic disease in majority of patients, and remission consolidation with autologous hematopoietic stem cell transplant (ASCT) remains the backbone of treatment in transplant-eligible patients.

OBJECTIVE

The aim of this multicenter cross-sectional nationwide retrospective study was to evaluate the epidemiology, etiology, and outcome of infections in patients with MM undergoing ASCT in 13 Polish transplant centers, carried out on behalf of the Infectious Complications Study Group of the Polish Adult Leukemia Group.

METHODS

A total number of consecutive 1374 patients with MM treated in Polish adult transplant centers from 2012 to 2014 were followed for infectious complications up to day +100 after ASCT in nationwide study.

RESULTS

Altogether 490 infection episodes in 336 patients (49% male, aged 21-72 years) were reported, including 145 episodes of neutropenic fever (103 patients) and 34 episodes of clinically documented infections (CDIs) (27 patients). Among microbiologically confirmed infections there were 251 episodes of bacterial infections (180 patients), 42 episodes of fungal infections (38 patients), and 18 episodes of viral infections (17 patients). The overall incidence of infections reached 13.1% for bacterial, 3.6% for fungal, and 1.3% for viral infections. There were 16 cases of infection-related deaths after ASCT (1.2%). The mortality risk factors included multidrug-resistant bacteria etiology (odds ratio [OR], 3.5; P = .033), coexistence of bacterial and fungal infection (OR, 6.3; P = .002), and CDI (OR, 5.5; P = .007).

CONCLUSION

ASCT in patients with MM was connected with low risk of life-threatening infections. However, multidrug-resistant bacteria bacterial etiology, mixed etiology, and CDI increased the risk of fatal outcome.

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.

Changing epidemiology of bloodstream infection in a 25-years hematopoietic stem cell transplant program: current challenges and pitfalls on empiric antibiotic treatment impacting outcomes

We aimed to describe epidemiology changes in bloodstream infections (BSI) episodes in hematopoietic stem cell transplant (HSCT) recipients throughout a 25-year period (1993-2017), comparing five-year time spans, and we evaluate their impact on inappropriate empirical antibiotic treatment (IEAT) and mortality. During the study period, 1164 BSI episodes were documented in patients undergoing HSCT (71.6% allogenic and 29% autologous). A significant decrease in gram-positive cocci (GPC) and increase in gram-negative bacilli (GNB) were observed (p < 0.001). Among GP, coagulase-negative staphylococci (CoNS) significantly decreased whereas rising E. faecium BSI was documented. Among GNB, E. coli, Pseudomonas aeruginosa and K. pneumoniae rates increased. Multidrug-resistant (MDR) GNB, especially ESBL-E. coli and MDR-P. aeruginosa, emerged in 2008 and has gradually increased. IEAT against MDR-P. aeruginosa, but not in other MDR-GNB, augmented throughout the study period. Overall, 30-day and related mortality rates were 12.7% and 7.7% respectively, both increasing over time (p < 0.001 and p = 0.025). In GNB, 30-day and related mortality were 18.5% and 12.8%, respectively, increasing over time (p < 0.001 and p = 0.004). To conclude, important BSI epidemiological changes were described in a 25-year period. Concerning increase in IEAT for P. aeruginosa infections and rising 30-day mortality rate were documented.

Age-dependent determinants of infectious complications profile in children and adults after hematopoietic cell transplantation: lesson from the nationwide study

Incidence and outcome of microbiologically documented bacterial/viral infections and invasive fungal disease (IFD) in children and adults after hematopoietic cell transplantation (HCT) were compared in 650 children and 3200 adults in multicenter cross-sectional nationwide study. Infections were diagnosed in 60.8% children and 35.0% adults, including respectively 69.1% and 63.5% allo-HCT, and 33.1% and 20.8% auto-HCT patients. The incidence of bacterial infections was higher in children (36.0% vs 27.6%; p < 0.0001). Infections with Gram-negative bacteria were more frequent than Gram-positives in adults (64.6% vs 44.8%; p < 0.0001). Outcome of bacterial infections was better in children (95.5% vs 91.4%; p = 0.0011). The IFD incidence (25.3% vs 6.3%; p < 0.0001) and outcome (88.0% vs 74.9%; p < 0.0001) were higher in children. The incidence of viral infections was higher in children after allo-HCT (56.3% vs 29.3%; p < 0.0001), and auto-HCT (6.6% vs 0.8%; p < 0.0001). Outcome of viral infections was better in children (98.6% vs 92.3%; p = 0.0096). Infection-related mortality was 7.8% in children and 18.4% in adults (p < 0.0001). No child after auto-HCT died of infection. Adult age, mismatched transplants, acute leukemia, chronic GVHD, CMV reactivation, infection with Gram-negatives, and duration of infection > 21 days were risk factors for death from infection. In conclusion, pediatric patients have 2.9-fold higher incidence and 2.5-fold better outcome of infections than adults after HCT.

The incidence, risk factors and outcomes of early bloodstream infection in patients with malignant hematologic disease after unrelated cord blood transplantation: a retrospective study

BACKGROUND

Bloodstream infection (BSI) is one of the major causes of morbidity and mortality for patients undergoing hematopoietic stem cell transplantation (HSCT). The unrelated cord blood transplantation (UCBT) can provided opportunities for patients without suitable donors for bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT), while few studies have addressed BSI after UCBT. The aim of this study was to analyse the incidence and risk factors of BSI, causative organisms, microbial resistance, and its impact on the clinical outcomes and survival of patients.

METHODS

There are 336 patients, were divided into two groups depending on whether developing BSI. Demographic characteristics, laboratory data, and clinical outcome were compared between different groups. The risk factors of BSI was examined using logistic regression and the survival was examined using the Kaplan-Meier method and log-rank test.

RESULTS

Ninety-two patients (27.4%) developed early BSI with 101 pathogenic bacteria isolated, and the median day of developing initial BSI was 4.5 d. Gram-negative bacteria were the most common isolate (60, 59.4%), followed by Gram-positive bacteria (40, 39.6%) and fungi (1, 1.0%). Thirty-seven (36.6%) isolates were documented as having multiple drug resistance (MDR). Myeloid malignancies, conditioning regimens including total body irradiation (TBI), and prolonged neutropenia were identified as the independent risk factors for early BSI. The 3-year OS was 59.9% versus 69.2% in the BSI group and no-BSI group (P = 0.0574), respectively. The 3-year OS of the MDR group was significantly lower than that of the non-BSI group (51.1% versus 69.2%, p = 0.013).

CONCLUSIONS

Our data indicate that the incidence of early BSI after UCBT was high, especially in patients with myeloid disease and a conditioning regimen including TBI and prolonged neutropenia. Early BSI with MDR after UCBT had a negative impact on long-term survival.

Stenotrophomonas maltophilia colonization during allogeneic hematopoietic stem cell transplantation is associated with impaired survival

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) offers potential cure to acute myeloid leukemia (AML) patients. However, infections with commensal bacteria are an important cause for non-relapse mortality (NRM). We have previously described the impact of multidrug-resistant organism (MDRO) colonization on the survival of allo-HSCT patients. In the aforementioned publication, according to consensus, we there did not consider the opportunistic gram-negative bacterium Stenotrophomonas maltophilia (S. maltophilia) to be an MDRO. Since rate of S. maltophilia colonization is increasing, and it is not known whether this poses a risk for allo-HSCT patients, we here analyzed here its effect on the previously described and now extended patient cohort. We report on 291 AML patients undergoing allo-HSCT. Twenty of 291 patients (6.9%) were colonized with S. maltophilia. Colonized patients did not differ from non-colonized patients with respect to their age, remission status before allo-HSCT, donor type and HSCT-comorbidity index. S. maltophilia colonized patients had a worse overall survival (OS) from 6 months up to 60 months (85% vs. 88.1% and 24.7% vs. 59.7%; p = 0.007) due to a higher NRM after allo-HSCT (6 months: 15% vs. 4.8% and 60 months: 40.1% vs. 16.2% p = 0.003). The main cause of mortality in colonized patients was infection (46.2% of all deaths) and in non-colonized patients relapse (58.8% of all deaths). 5/20 colonized patients developed an invasive infection with S. maltophilia. The worse OS after allo-HSCT due to higher infection related mortality might implicate the screening of allo-HSCT patients for S. maltophilia and a closer observation of colonized patients as outpatients.

Incidence, Risk Factors and Outcome of Pre-engraftment Gram-Negative Bacteremia After Allogeneic and Autologous Hematopoietic Stem Cell Transplantation: An Italian Prospective Multicenter Survey

Background

Gram-negative bacteremia (GNB) is a major cause of illness and death after hematopoietic stem cell transplantation (HSCT), and updated epidemiological investigation is advisable.

Methods

We prospectively evaluated the epidemiology of pre-engraftment GNB in 1118 allogeneic HSCTs (allo-HSCTs) and 1625 autologous HSCTs (auto-HSCTs) among 54 transplant centers during 2014 (SIGNB-GITMO-AMCLI study). Using logistic regression methods. we identified risk factors for GNB and evaluated the impact of GNB on the 4-month overall-survival after transplant.

Results

The cumulative incidence of pre-engraftment GNB was 17.3% in allo-HSCT and 9% in auto-HSCT. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most common isolates. By multivariate analysis, variables associated with GNB were a diagnosis of acute leukemia, a transplant from a HLA-mismatched donor and from cord blood, older age, and duration of severe neutropenia in allo-HSCT, and a diagnosis of lymphoma, older age, and no antibacterial prophylaxis in auto-HSCT. A pretransplant infection by a resistant pathogen was significantly associated with an increased risk of posttransplant infection by the same microorganism in allo-HSCT. Colonization by resistant gram-negative bacteria was significantly associated with an increased rate of infection by the same pathogen in both transplant procedures. GNB was independently associated with increased mortality at 4 months both in allo-HSCT (hazard ratio, 2.13; 95% confidence interval, 1.45-3.13; P <.001) and auto-HSCT (2.43; 1.22-4.84; P = .01).

Conclusions

Pre-engraftment GNB is an independent factor associated with increased mortality rate at 4 months after auto-HSCT and allo-HSCT. Previous infectious history and colonization monitoring represent major indicators of GNB.

Clinical Trials registration

NCT02088840.

Impact of fluoroquinolone prophylaxis during neutropenia on bloodstream infection: Data from a surveillance program in 8755 patients receiving high-dose chemotherapy for haematologic malignancies between 2009 and 2014

OBJECTIVES

Antibacterial chemoprophylaxis with fluoroquinolones (FQPx) has been commonly used in cancer patients with neutropenia, but its efficacy has been challenged by the emergence of fluoroquinolone resistance.

METHODS

The impact of FQPx on bloodstream infections (BSI) during neutropenia after high-dose chemotherapy for haematologic malignancies was evaluated through a multicenter hospital infection surveillance system for the period 2009-2014.

RESULTS

Among 8755 patients (4223 allogeneic [allo-] HSCT, 3602 autologous [auto-] HSCT, 930 high-dose chemotherapy for acute leukemia [HDC]), 5302 (61%) had received FQPx. Administration of FQPx was associated with fewer Gram-negative BSI in the overall study cohort patients (4.6% vs. 7.7%, adjusted subdistribution hazard ratio [aSHR] 0.59, 95%CI 0.50-0.70), in patients with HDC (3.7% vs. 9.2%, adjusted subdistribution hazard ratio [aSHR] 0.40, 95%CI 0.22-0.70) and auto-HSCT patients (4% vs. 9%, aSHR 0.43, 95%CI 0.33-0.56). In HDC patients, FQPx was associated with a marked reduction in all-cause mortality during neutropenia (2.3% vs. 7.8%, aSHR 0.30, 95%CI 0.15-0.58). Patients receiving FQPx had significantly more BSIs due to ESBL-positive Enterobacteriacea (0.8 vs. 0.3%, RR 2.2, 95%CI 1.17-4.26). BSIs by MRSA (n = 5) and VRE (n = 11) were rare in our cohort.

CONCLUSIONS

As used in the participating centers, FQPx was associated with reduced Gram-negative BSI and improved survival among HDC patients. Among HSCT patients, the benefits were less clear. If adapted to local resistance patterns and patient characteristics, FQPx still may be useful in the management of patients with haematologic malignancies.

De-Escalation and Discontinuation of Empirical Antibiotic Treatment in a Cohort of Allogeneic Hematopoietic Stem Cell Transplantation Recipients during the Pre-Engraftment Period

To investigate rates and outcomes of antibiotic de-escalation during pre-engraftment neutropenia in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. 110 consecutive HSCTs performed between January 2013 and March 2014 were analyzed. De-escalation was defined as narrowing the spectrum of antibiotic treatment either within (early) or after 96 hours (late) from starting antibiotics. Discontinuation, considered a form of de-escalation, was defined as stopping antibiotics before engraftment. De-escalation failure was defined as restarting/escalating antibiotics within 96 hours after de-escalation. Predictors of de-escalation were analyzed. Among 102 patients who started antibiotics and were included, 68 (67%) received monotherapy (mainly piperacillin-tazobactam, n = 58), whereas 34 (33%) received combination therapy (mainly meropenem plus glycopeptide, n = 24). Median duration of neutropenia was 17 days. Bloodstream infections (BSIs) were diagnosed in 28 patients (20%). Early de-escalation rate was 25.5% (n = 26) and mostly consisted of reducing the spectrum of β-lactams (n = 11, 42%). In comparison with theoretical scenario of continuing therapy until engraftment, the median savings in terms of antibiotic days were 10 for meropenem, 8 for piperacillin-tazobactam, and 7 for vancomycin. Failure rate of early de-escalation was 15% (4/26). Late de-escalation rate was 30.4% (n = 31) and failure rate 19% (6/31). The rate of de-escalation any time before engraftment was 55.9% (n = 57), including discontinuation in 33 patients (32%). Death at day 60 after HSCT occurred in 3 patients who never underwent de-escalation. Acute myeloid disease and BSIs were independent predictors of early de-escalation. De-escalation, including discontinuation, is feasible and safe in pre-engraftment neutropenia after allogeneic HSCT.

Epidemiology, risk factors and outcomes of multi-drug-resistant bloodstream infections in haematopoietic stem cell transplant recipients: importance of previous gut colonization

BACKGROUND

Bloodstream infections (BSI) are a major complication in the early phase of a haematopoietic stem cell transplant (HSCT).

AIM

To describe the incidence and risk factors for BSI occurring in the pre-engraftment phase of HSCT, and its impact on mortality.

METHODS

Clinical variables of 232 HSCT patients were analysed retrospectively between 2014 and 2015. Univariate Cox regression analyses were performed to test the association between each covariate and the outcome. Covariates with P < 0.10 on univariate analysis were included in a multiple Cox regression analysis using a backward elimination method.

FINDINGS

The cumulative incidence of BSI was 25.4%, mainly caused by Gram-negative bacteria (GNB) (55.2%). Approximately 40.5% of the patients had gut colonization by multi-drug-resistant (MDR) bacteria (vancomycin-resistant enterococcus and carbapenem-resistant GNB). Among patients colonized by MDR GNB, 20% developed an overt BSI due to MDR bacteria with the same pattern of sensitivity. Of the 13 deaths related to infection, 10 were patients with BSI caused by MDR GNB. The independent risk factors for BSI were gut colonization by MDR bacteria including GNB (P < 0.001) and duration of neutropenia >10 days (P = 0.005), and those associated with BSI caused by MDR bacteria were age >62 years (P = 0.03), use of total parenteral nutrition (TPN) (P < 0.001) and previous gut colonization by MDR GNB (P = 0.002).

CONCLUSIONS

Previous gut colonization by MDR was an independent risk factor for BSI, together with TPN and age, and had an impact on outcome. These findings suggest that gut decolonization may be a potential strategy to prevent BSI.

Risk factors for cefepime nonsusceptible Gram-negative infections in allogeneic hematopoietic cell transplant recipients

Purpose

Allogeneic hematopoietic cell transplant recipients undergo myelosuppressive chemotherapy to allow engraftment of stem cells and are at particularly high risk for bacterial infections and adverse outcomes. Patients undergoing hematopoietic cell transplant are at increased risk for healthcare-associated infections, including infections with multidrug-resistant pathogens. Cefepime is a commonly prescribed antibiotic for empiric therapy in hematopoietic cell transplant patients, but there is minimal data describing cefepime resistance rates, risk factors for resistance, and clinical outcomes associated with cefepime-resistant infections.

Methods

Adult (≥18 years old) allogeneic hematopoietic cell transplant recipients with a culture positive for a gram-negative rod between January 2010 and January 2016 were spilt into two groups: cefepime susceptible and cefepime nonsusceptible . The primary objective of this study was to identify risk factors for cefepime nonsusceptible through multivariable logistic regression.

Results

A total of 107 patients were included (27 cefepime nonsusceptible, 80 cefepime-susceptible), yielding a 25.2% nonsusceptibility rate. Multivariable analysis yielded age >60 years old, Klebsiella spp. infection, Acinetobacter spp. infection, healthcare exposures within 90 days, acute gastrointestinal graft-vs-host-disease, and chronic graft-vs-host-disease at multiple locations as significant risk factors for cefepime nonsusceptible. The receiver operating characteristic area under the curve of the model was 0.851. Thirty-day all-cause mortality (29.6% versus 16.3%, p = 0.13) and length of hospitalization (19 versus 12.5 days, p = 0.0650) were numerically higher in the cefepime nonsusceptible group.

Conclusions

Hematopoietic cell transplant patients with acute gastrointestinal graft versus host disease, extensive chronic graft-vs-host-disease, advanced age, previous healthcare exposures, or infections with Klebsiella and Acinetobacter are at increased risk for cefepime nonsusceptible. Patients infected with cefepime nonsusceptible pathogens may have higher rates of mortality and length of hospitalization.