Invasive fungal infections in paediatric acute myeloid leukaemia

A comprehensive assessment of the prolonged febrile neutropenia evaluation in pediatric oncology patients

BACKGROUND

Pediatric oncology patients with prolonged (≥96 hours) febrile neutropenia (absolute neutrophil count < 500/μL) often undergo an evaluation for invasive fungal disease (IFD) and other infections. Current literature suggests that beta-D-glucan (BDG), galactomannan, bronchoalveolar lavage (BAL), and computed tomography (CT) scans (sinus, chest, and abdomen/pelvis) may help determine a diagnosis in this population.

METHODS

In a retrospective cohort study of all cancer/stem cell transplant patients (diagnosed 2005-2019) from one pediatric hospital, all episodes with prolonged febrile neutropenia or IFD evaluations (defined as sending a fungal biomarker or performing a CT scan to assess for infection) were identified.

RESULTS

In total, 503 episodes met inclusion criteria and 64% underwent IFD evaluations. In total, 36.4% of episodes documented an infection after initiation of prolonged febrile evaluation, most commonly Clostridioides difficile colitis (6.4%) followed by a true bacterial bloodstream infection (BSI) (5.2%), proven/probable IFD (4.8%), and positive respiratory pathogen panel (3.6%). There was no difference in sinus CTs showing sinusitis (74% vs 63%, p = 0.46), whereas 32% of abdomen/pelvis CTs led to a non-IFD diagnosis, and 25% of chest CTs showed possible pneumonia. On chest CT, the positive predictive value (PPV) for IFD was 19% for nodules and 14% for tree and bud lesions. BDG had a PPV of 25% for IFD and GM 50%. BAL diagnosed IFD once and pneumocystis jirovecii pneumonia twice.

CONCLUSIONS

Chest CTs and abdomen/pelvis CTs provide clinically relevant information during the prolonged febrile neutropenia evaluation, whereas BDG, galactomannan, BAL, and sinus CTs have less certain utility.

Adverse effects of antibiotics in children with cancer: are short-course antibiotics for febrile neutropenia part of the solution?

INTRODUCTION

Febrile neutropenia is a common complication experienced by children with cancer or those undergoing hematopoietic stem cell transplantation. Repeated episodes of febrile neutropenia result in cumulative exposure to broad-spectrum antibiotics with potential for a range of serious adverse effects. Short-course antibiotics, even in patients with high-risk febrile neutropenia, may offer a solution.

AREAS COVERED

This review addresses the known broad effects of antibiotics, highlights developments in understanding the relationship between cancer, antibiotics, and the gut microbiome, and discusses emerging evidence regarding long-term adverse antibiotic effects. The authors consider available evidence to guide the duration of empiric antibiotics in pediatric febrile neutropenia and directions for future research.

EXPERT OPINION

Broad-spectrum antibiotics are associated with antimicrobial resistance, Clostridioides difficile infection, invasive candidiasis, significant disturbance of the gut microbiome and may seriously impact outcomes in children with cancer or undergoing allogenic hematopoietic stem cell transplant. Short-course empiric antibiotics are likely safe in most children with febrile neutropenia and present a valuable opportunity to reduce the risks of antibiotic exposure.

Role of Polymerase Chain Reaction-Based Diagnosis of Respiratory Viruses in Febrile Neutropenic Patients

Background Neutropenic patients are commonly affected by respiratory infections, whereas respiratory viral infections causing high morbidity and mortality are routinely diagnosed in developing countries like India. Our study aimed to investigate the prevalence of respiratory viral infections in pediatric cancer patients with febrile neutropenia.  Methods This prospective study was performed on 45 neutropenia patients with hematological malignancies. Nasal swabs were collected and analyzed by real-time multiplex polymerase chain reaction (PCR), covering the following viruses: influenza A virus, influenza B virus, human parainfluenza virus (subtypes 1-4), human respiratory syncytial virus A and B, enterovirus, human-coronavirus (HCoV: HKU1, NL63, 229E, and OC43), human bocavirus, adenovirus, human rhinovirus, human-metapneumovirus A and B, human paraechovirus, and a bacterium Mycoplasma pneumoniae. Patients enrolled in the study since the COVID-19 pandemic was also detected for the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results Of the 45 cases included in our study, 26 cases showed the presence of at least one positivity by PCR (57.7%): 23 patients had monoinfection with only one virus, two patients were found positive for coinfection with two viruses, and one patient was found positive for three viruses. The most detected viruses were human rhinovirus (26.9%, n=7) and coronavirus 19 (19.2%, n=5). A total of 11.5% of the patients had multiple viral infections. About 19 (42.2%) of the patients enrolled in our study had no viral pathogen detected. Conclusion We found that respiratory viruses contribute significantly to the development of neutropenic fever, as evidenced by the results of our prospective study. Individualizing infection treatment can reduce antibiotic use in immunocompromised patients. Thus, routine screening for viremia may be warranted in this clinical setting.

Invasive fungal diseases impact on outcome of childhood ALL - an analysis of the international trial AIEOP-BFM ALL 2009

In children with acute lymphoblastic leukemia (ALL), risk groups for invasive fungal disease (IFD) with need for antifungal prophylaxis are not well characterized, and with the advent of new antifungal compounds, current data on outcome are scarce. Prospectively captured serious adverse event reports of children enrolled in the international, multi-center clinical trial AIEOP-BFM ALL2009 were screened for proven/probable IFD, defined according to the updated EORTC/MSG consensus definitions. In a total of 6136 children (median age 5.2 years), 224 proven/probable IFDs (65 yeast and 159 mold) were reported. By logistic regression, the risk for proven/probable IFDs was significantly increased in children ≥12 years and those with a blast count ≥10% in the bone marrow on day 15 (P < 0.0001 each). Proven/probable IFDs had a 6-week and 12-week mortality of 10.7% and 11.2%, respectively. In the multivariate analysis, the hazard ratio for event-free and overall survival was significantly increased for proven/probable IFD, age ≥12 years, and insufficient response to therapy (P < 0.001, each). Our data define older children with ALL and those with insufficient treatment-response at high risk for IFD. As we show that IFD is an independent risk factor for event-free and overall survival, these patients may benefit from targeted antifungal prophylaxis.

Astaxanthin decreases the growth-inhibitory dose of cytarabine and inflammatory response in the acute lymphoblastic leukemia cell line NALM-6

BACKGROUND

In spite of the great progress in acute lymphoblastic leukemia (ALL) treatment, a large number of patients still suffer from chemotherapy drug toxicity. As a routine medication for ALL treatment, cytarabine (Ara-C) has many side effects on the patients. Astaxanthin (ASX), on the other hand, is a carotenoid with antioxidant, anti-inflammatory and anti-cancer properties.

PURPOSE

The present study investigated the effects of ASX in combination with Ara-C on cell proliferation, apoptosis induction, and cell cycle arrest in NALM-6 cell line.

METHODS

NALM6 cells were treated with different concentrations of ASX, Ara-C, and their co-treatment. Cytotoxic effects were evaluated using MTT assay. After treating the cells with the IC50 dose of ASX, Ara-C and their co-treatment, we studied apoptosis induction, cell cycle arrest, and expression of apoptotic, anti-apoptotic, and inflammatory genes.

RESULT

MTT assay demonstrated that co-treatment of cytarabine and ASX had greater cytotoxicity effects compared with the IC50 dose of Ara-C alone. After 48 h of treatment of NALM-6 cells with the combination dose, expression levels of apoptotic genes (P53, caspase-8, 3), the anti-apoptotic gene (Bcl-xL) and inflammatory genes (IL-6, TNF-α) changed significantly compared to the untreated group (p < 0.05).

CONCLUSIONS

Co-treatment of ASX and Ara-C has synergism effects on apoptosis pathways, cell proliferation inhibition, and decreased inflammation.

Pediatric Invasive Fungal Risk Score in Cancer and Hematopoietic Stem Cell Transplantation Patients With Febrile Neutropenia

BACKGROUND

Invasive fungal diseases (IFDs) are opportunistic infections that result in significant morbidity and mortality in pediatric oncology patients. Predictive risk tools for IFD in pediatric cancer are not available.

METHODS

We conducted a 7-year retrospective study of pediatric oncology patients with a diagnosis of febrile neutropenia at UCM Comer Children's Hospitals. Fourteen clinical, laboratory, and treatment-related risk factors for IFD were analyzed. Stepwise variable selection for multiple logistic regression was used to develop a risk prediction model for IFD. Two comparative analyses have been conducted: (i) all suspected IFD cases and (ii) all proven and probable IFD cases.

RESULTS

A total of 667 febrile neutropenia episodes were identified in 265 patients. IFD was diagnosed in 62 episodes: 13 proven, 27 probable, and 22 possible. In the final multiple logistic regression models, 5 variables were independently significant for both analyses: fever days, neutropenia days, hypotension, and absolute lymphocyte count <250 at the time of diagnosis. The odds ratio and a relative weight for each factor were then calculated and summed to calculate a predictive score. A risk score of ≤4 and ≤5 (10/11 maximum) for each model signifies low risk, respectively (<1.2% incidence). Model discrimination was evaluated by the area under the receiver operator characteristics curve with an area under the curve of 0.95/0.94 for each model.

CONCLUSION

Our prediction IFD risk models perform well, are easy-to-use, and are based on readily available clinical data. Profound lymphopenia absolute lymphocyte count <250 mm3 could serve as a new important prognostic marker for the development of IFD in pediatric cancer and hematopoietic stem cell transplant patients.

Fungal diagnostic testing and therapy: navigating the neutropenic period in children with high-risk leukemia

Children, adolescents, and young adults receiving intensive chemotherapy for acute myeloid leukemia or high-risk or relapsed acute lymphoblastic leukemia sustain prolonged periods of neutropenia that predispose them to invasive fungal disease (IFD). For many decades the standard of care for these patients was to initiate empirical antifungal therapy after a period of prolonged fever and neutropenia. Recent publications have yielded important evidence on the utility of different diagnostic and therapeutic approaches aimed at reducing the impact of IFD among these patients during these vulnerable periods. This case-based review highlights and interprets the published data to provide context for the IFD diagnostic and therapeutic recommendations proposed in multiple published guidelines. Personalized approaches are offered at points where evidence is lacking. Time points where specific knowledge gaps exist are identified along the clinical trajectory of the prolonged neutropenic period to illustrate areas for future investigation.

Invasive fungal disease in children with acute myeloid leukaemia: An Australian multicentre 10-year review

BACKGROUND

Invasive fungal disease (IFD) is a common and important complication in children with acute myeloid leukaemia (AML). We describe the epidemiology of IFD in a large multicentre cohort of children with AML.

METHODS

As part of the retrospective multicentre cohort TERIFIC (The Epidemiology and Risk factors for Invasive Fungal Infections in immunocompromised Children) study, proven/probable/possible IFD episodes occurring in children with primary or relapsed/refractory AML from 2003 to 2014 were analysed. Crude IFD prevalence, clinical characteristics, microbiology and treatment were assessed. Kaplan-Meier survival analysis was used to estimate 6-month survival.

RESULTS

There were 66 IFD episodes diagnosed in 63 children with AML. The majority (75.8%) of episodes occurred in the context of primary AML therapy. During primary AML therapy, the overall prevalence was 20.7% (95% CI 15.7%-26.5%) for proven/probable/possible IFD and 10.3% (95% CI 6.7%-15.0%) for proven/probable IFD. Of primary AML patients, 8.2% had IFD diagnosed during the first cycle of chemotherapy. Amongst pathogens implicated in proven/probable IFD episodes, 74.4% were moulds, over a third (37.9%) of which were non-Aspergillus spp. Antifungal prophylaxis preceded 89.4% of IFD episodes, most commonly using fluconazole (50% of IFD episodes). All-cause mortality at 6 months from IFD diagnosis was 16.7% with IFD-related mortality of 7.6% (all in cases of proven IFD).

CONCLUSIONS

IFD is a common and serious complication during paediatric AML therapy. Mould infections, including non-Aspergillus spp. predominated in this cohort. A systematic approach to the identification of patients at risk, and a targeted prevention strategy for IFD is needed.

Clinical Characteristics of Invasive Fungal Infections in Pediatric Oncology Patients With Solid Tumors

Invasive fungal infections (IFIs) are an important cause of morbidity and mortality in children with cancer. Studies on the clinical characteristics of IFI in children with solid tumors are limited. This Dutch retrospective cohort study reviewed the medical records of 61 children with solid tumors to analyze the clinical characteristics during their full treatment period. Seven IFI episodes were reported in 6/61 patients (10%), all diagnosed with intermediate-risk or high-risk Wilms tumor or neuroblastoma. Larger studies are necessary to reveal the determinants of IFI in this group of patients and the value of fungal prophylaxis.

Fungal infections in children with haematologic malignancies and stem cell transplant recipients

Children with haematologic malignancies and haematopoietic stem cell transplant recipients are at high risk for invasive fungal diseases (IFD). There has been an increased number of at-risk children over the past two decades due to improvements in cancer therapies resulting in improved survival of children with high-risk and refractory malignancies. The predominant organisms that cause IFD include Candida spp., Aspergillus spp. and the Mucorales molds. Clinical presentations of IFD vary based on host immune status and the causative organism. Though serum biomarkers such as the galactomannan assay and beta-D-glucan assay have been validated in adults, there are limited data regarding their diagnostic value in children. Thus, the gold standard for IFD diagnosis remains tissue biopsy with histopathological and microbiological evaluation. Treatment of IFD is multimodal and involves antifungal drugs, correction of immune dysfunction and surgical resection when feasible. Paediatric practice regarding IFD is largely extrapolated from data generated in adult patients; in this review, we evaluate both primary paediatric studies and guidelines intended for adult patients that are applied to paediatric patients. There remain significant knowledge gaps with respect to the prevention, diagnosis and treatment of IFD in immunocompromised children, and further research is needed to help guide management decisions.

Mucormycosis in children with haematological malignancies is a salvageable disease: a report from the Israeli Study Group of Childhood Leukemia

Mucormycosis has emerged as an increasingly important cause of morbidity and mortality in immunocompromised patients, but contemporary data in children are lacking. We conducted a nationwide multicentre study to investigate the characteristics of mucormycosis in children with haematological malignancies. The cohort included 39 children with mucormycosis: 25 of 1136 children (incidence 2·2%) with acute leukaemias prospectively enrolled in a centralized clinical registry in 2004-2017, and an additional 14 children with haematological malignancies identified by retrospective search of the databases of seven paediatric haematology centres. Ninety-two percent of mucormycosis cases occurred in patients with acute leukaemias. Mucormycosis was significantly associated with high-risk acute lymphoblastic leukaemia (OR 3·75; 95% CI 1·51-9·37; P = 0·004) and with increasing age (OR 3·58; 95% CI 1·24-9·77; P = 0·01). Fifteen patients (38%) died of mucormycosis. Rhinocerebral pattern was independently associated with improved 12-week survival (OR 9·43; 95% CI 1·47-60·66; P = 0·02) and relapsed underlying malignancy was associated with increased 12-week mortality (OR 6·42; 95% CI, 1·01-40·94; P = 0·05). In patients receiving frontline therapy for their malignancy (n = 24), one-year cumulative mucormycosis-related mortality was 21 ± 8% and five-year overall survival was 70 ± 8%. This largest paediatric population-based study of mucormycosis demonstrates that children receiving frontline therapy for their haematological malignancy are often salvageable.

Frequency and Determinants of Invasive Fungal Infections in Children With Solid and Hematologic Malignancies in a Nonallogeneic Stem Cell Transplantation Setting: A Narrative Review

Invasive fungal infections (IFIs) are an important cause of morbidity and mortality in children with cancer. An overview of studies on the frequency and determinants of IFI in pediatric oncology patients in nonallogeneic stem cell transplantation settings is lacking. We performed a literature review in Pubmed and Embase, and included 13 prospective and 23 retrospective studies. The IFI frequency (proven/probable based on EORTC criteria) in nonallogeneic stem cell transplantation pediatric cancer patients ranged between 1.0% and 38.0%, with the highest frequencies reported in hematologic malignancies. The most common fungal species seen in the studied population was Candida, followed by Aspergillus. IFI are not well investigated in solid tumor patients. Significant recurrent determinants from univariate analysis were the diagnosis acute myeloid leukemia, (prolonged) neutropenia and an older age (above 10 years). The only 2 significant determinants based on multivariate analysis were the preceding number of days of broad-spectrum antibiotics (odds ratio, 1.05; 95% confidence interval, 1.02-1.07; P=0.0006) and the number of days of corticosteroids (odds ratio, 1.05; 95% confidence interval, 1.02-1.09; P=0.005), that were both based on a group of acute myeloid leukemia patients only. Future studies are necessary to determine the frequency and determinants of IFI in pediatric oncology including a representative number of solid tumor patients.

Epidemiology of invasive fungal infections in immunocompromised children; an Australian national 10-year review

BACKGROUND

A thorough understanding of local and contemporary invasive fungal infection (IFI) epidemiology in immunocompromised children is required to provide a rationale for targeted prevention and treatment strategies.

METHODS

Retrospective data over 10 years from four tertiary pediatric oncology and hematopoietic stem cell transplant (HSCT) units across Australia were analyzed to report demographic, clinical, and mycological characteristics of IFI episodes, and crude IFI prevalence in select oncology/HSCT groups. Kaplan-Meier survival analyses were used to calculate 180-day overall survival.

RESULTS

A total of 337 IFI episodes occurred in 320 children, of which 149 (44.2%), 51 (15.1%), and 110 (32.6%) met a modified European Organization for Research and Treatment of Cancer (mEORTC) criteria for proven, probable, and possible IFI, respectively. There were a further 27 (8.0%) that met a "modified possible IFI" criteria. Median age at IFI diagnosis was 8.4 years. Crude mEORTC IFI prevalence in acute lymphoblastic leukemia, acute myeloid leukemia, solid tumor, and allogeneic HSCT cohorts was 10.6%, 28.2%, 4.4%, and 11.7%, respectively. Non-Aspergillus species represented 48/102 (47.1%) molds identified, and non-albicans Candida represented 66/93 (71.0%) yeasts identified. There were 56 deaths among 297 children who met mEORTC criteria, with 180-day overall survival for proven, probable, and possible IFIs of 79.7%, 76.2%, and 84.4%, respectively.

CONCLUSION

Non-Aspergillus molds and non-albicans Candida contributed substantially to pediatric IFI in our study, with high IFI prevalence in leukemia and allogeneic HSCT cohorts. Inclusion of IFIs outside of European Organization for Research and Treatment of Cancer criteria revealed an IFI burden that would go otherwise unrecognized in published reports.

A non-randomized trial to assess the safety, tolerability, and pharmacokinetics of posaconazole oral suspension in immunocompromised children with neutropenia

Background

Posaconazole (POS) is a potent triazole antifungal agent approved in adults for treatment and prophylaxis of invasive fungal infections (IFIs). The objectives of this study were to evaluate the pharmacokinetics (PK), safety, and tolerability of POS oral suspension in pediatric subjects with neutropenia.

Methods

This was a prospective, multicenter, sequential dose-escalation study. Enrolled subjects were divided into 3 age groups: AG1, 7 to <18 years; AG2, 2 to <7 years; and AG3, 3 months to <2 years. AG1 and AG2 were divided into 3 dosage cohorts: DC1, 12 mg/kg/day divided twice daily (BID); DC2, 18 mg/kg/day BID; and DC3, 18 mg/kg/day divided thrice daily (TID). AG3 was also divided into DC1 and DC2; however, no subjects were enrolled in DC2. Subjects received 7–28 days of POS oral suspension. PK samples were collected at predefined time points. The POS PK target was predefined as ~90% of subjects with C_avg (AUC /dosing interval) between 500 and 2500 ng/mL, with an anticipated mean steady state C_avg exposure of ~1200 ng/mL.

Results

The percentage of subjects meeting the PK target was <90% across all age groups and dosage cohorts (range: 31% to 80%). The percentage of subjects that achieved the C_avg target of 500 to 2500 ng/mL on Day 7 ranged from 31% to 80%, with the lowest proportion in subjects 2 to <7 years receiving 12 mg/kg/day BID (AG2/DC1) and the highest proportion in subjects 7 to <18 years receiving 18 mg/kg/day TID (AG1/DC3). At all three dose levels (12 mg/kg/day BID, 18 mg/kg/day BID and 18 mg/kg/day TID), subjects in AG1 (7 to <18 years old) had higher mean PK exposures at steady state than those in AG2. High variability in exposures was observed in all groups. POS oral suspension was generally well tolerated and most of the reported adverse events were related to the subjects’ underlying diseases.

Conclusion

The POS PK target of 90% of subjects with C_avg between 500 and 2500 ng/mL was not achieved in any of the age groups across the different dosage cohorts. New formulations of the molecule with a greater potential to achieve the established PK target are currently under investigation.

Trial registration

ClinicalTrials.gov identifier: NCT01716234

Risk Factors for Invasive Fungal Disease in Pediatric Cancer and Hematopoietic Stem Cell Transplantation: A Systematic Review

BACKGROUND

Although a number of risk factors have been associated with invasive fungal disease (IFD), a systematic review of the literature to document pediatric-specific factors has not been performed.

METHODS

We used the Ovid SP platform to search Medline, Medline In-Process, and Embase for studies that identified risk factors for IFD in children with cancer or those who undergo hematopoietic stem cell transplantation (HSCT). We included studies if they consisted of children or adolescents (<25 years) who were receiving treatment for cancer or undergoing HSCT and if the study evaluated risk factors among patients with and those without IFD.

RESULTS

Among the 3566 studies screened, 22 studies were included. A number of pediatric factors commonly associated with an increased risk for IFD were confirmed, including prolonged neutropenia, high-dose steroid exposure, intensive-timing chemotherapy for acute myeloid leukemia, and acute and chronic graft-versus-host disease. Increasing age, a factor not commonly associated with IFD risk, was identified as a risk factor in multiple published cohorts.

CONCLUSIONS

With this systematic review, we have confirmed IFD risk factors that are considered routinely in daily clinical practice. Increasing age should also be considered when assessing patient risk for IFD. Future efforts should focus on defining more precise thresholds for a particular risk factor (ie, age, neutropenia duration) and on development of prediction rules inclusive of individual factors to further refine the risk prediction.

Guideline for the Management of Fever and Neutropenia in Children With Cancer and Hematopoietic Stem-Cell Transplantation Recipients: 2017 Update

Purpose To update a clinical practice guideline (CPG) for the empirical management of fever and neutropenia (FN) in children with cancer and hematopoietic stem-cell transplantation recipients. Methods The International Pediatric Fever and Neutropenia Guideline Panel is a multidisciplinary and multinational group of experts in pediatric oncology and infectious diseases that includes a patient advocate. For questions of risk stratification and evaluation, we updated systematic reviews of observational studies. For questions of therapy, we conducted a systematic review of randomized trials of any intervention applied for the empirical management of pediatric FN. The Grading of Recommendation Assessment, Development and Evaluation approach was used to make strong or weak recommendations and to classify levels of evidence as high, moderate, low, or very low. Results Recommendations related to initial presentation, ongoing management, and empirical antifungal therapy of pediatric FN were reviewed; the most substantial changes were related to empirical antifungal therapy. Key differences from our 2012 FN CPG included the listing of a fourth-generation cephalosporin for empirical therapy in high-risk FN, refinement of risk stratification to define patients with high-risk invasive fungal disease (IFD), changes in recommended biomarkers and radiologic investigations for the evaluation of IFD in prolonged FN, and a weak recommendation to withhold empirical antifungal therapy in IFD low-risk patients with prolonged FN. Conclusion Changes to the updated FN CPG recommendations will likely influence the care of pediatric patients with cancer and those undergoing hematopoietic stem-cell transplantation. Future work should focus on closing research gaps and on identifying ways to facilitate implementation and adaptation.

Galactomannan, β-D-Glucan, and Polymerase Chain Reaction-Based Assays for the Diagnosis of Invasive Fungal Disease in Pediatric Cancer and Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

We systematically reviewed and analyzed the available data for galactomannan (GM), β-D-glucan (BG), and polymerase chain reaction (PCR)-based assays to detect invasive fungal disease (IFD) in patients with pediatric cancer or undergoing hematopoietic stem cell transplantation when used as screening tools during immunosuppression or as diagnostic tests in patients presenting with symptoms such as fever during neutropenia (FN). Of 1532 studies screened, 25 studies reported on GM (n = 19), BG (n = 3), and PCR (n = 11). All fungal biomarkers demonstrated highly variable sensitivity, specificity, and positive predictive values, and these were generally poor in both clinical settings. GM negative predictive values were high, ranging from 85% to 100% for screening and 70% to 100% in the diagnostic setting, but failure to identify non-Aspergillus molds limits its usefulness. Future work could focus on the usefulness of combinations of fungal biomarkers in pediatric cancer and HSCT.

Frequent Respiratory Viral Infections in Children with Febrile Neutropenia - A Prospective Follow-Up Study

OBJECTIVE

Febrile neutropenia is common in children undergoing chemotherapy for the treatment of malignancies. In the majority of cases, the cause of the fever is unknown. Although respiratory viruses are commonly associated with this condition, the etiologic significance of this finding remains unclear and is therefore the subject of this study.

STUDY DESIGN

Nasopharyngeal aspirates were collected during 87 episodes of febrile neutropenia in children age 0-18 years, being treated at a children's oncology unit between January 2013 and June 2014. Real-time polymerase chain reaction was used to determine the presence of 16 respiratory viruses. Follow-up samples were collected from children who tested positive for one or more respiratory viruses. Rhinoviruses were genotyped by VP4/VP2 sequencing. Fisher's exact test and Mann-Whitney U test were used for group comparisons.

RESULTS

At least one respiratory virus was detected in samples from 39 of 87 episodes of febrile neutropenia (45%), with rhinoviruses the most frequently detected. Follow-up samples were collected after a median of 28 days (range, 9-74 days) in 32 of the 39 virus-positive episodes. The respiratory viral infection had resolved in 25 episodes (78%). The same virus was detected at follow-up in one coronavirus and six rhinovirus episodes. Genotyping revealed a different rhinovirus species in two of the six rhinovirus infections.

CONCLUSION

The frequency of respiratory viral infections in this group of patients suggests an etiologic role in febrile neutropenia. However, these findings must be confirmed in larger patient cohorts.

Impaired killing of Candida albicans by granulocytes mobilized for transfusion purposes: a role for granule components

Granulocyte transfusions are used to treat neutropenic patients with life-threatening bacterial or fungal infections that do not respond to anti-microbial drugs. Donor neutrophils that have been mobilized with granulocyte-colony stimulating factor (G-CSF) and dexamethasone are functional in terms of antibacterial activity, but less is known about their fungal killing capacity. We investigated the neutrophil-mediated cytotoxic response against C. albicans and A. fumigatus in detail. Whereas G-CSF/dexamethasone-mobilized neutrophils appeared less mature as compared to neutrophils from untreated controls, these cells exhibited normal ROS production by the NADPH oxidase system and an unaltered granule mobilization capacity upon stimulation. G-CSF/dexamethasone-mobilized neutrophils efficiently inhibited A. fumigatus germination and killed Aspergillus and Candida hyphae, but the killing of C. albicans yeasts was distinctly impaired. Following normal Candida phagocytosis, analysis by mass spectrometry of purified phagosomes after fusion with granules demonstrated that major constituents of the antimicrobial granule components, including major basic protein (MBP), were reduced. Purified MBP showed candidacidal activity, and neutrophil-like Crisp-Cas9 NB4-KO-MBP differentiated into phagocytes were impaired in Candida killing. Together, these findings indicate that G-CSF/dexamethasone-mobilized neutrophils for transfusion purposes have a selectively impaired capacity to kill Candida yeasts, as a consequence of an altered neutrophil granular content.

Cryptococcus neoformans in the respiratory tract of squirrels, Callosciurus finlaysonii (Rodentia, Sciuridae)

Cryptococcosis is a fungal disease acquired from the environment, for which animals may serve as sentinels for human exposure. The occurrence of Cryptococcus spp. in the respiratory tract of 125 squirrels, Callosciurus finlaysonii, trapped in Southern Italy, was assessed. Upon examination of nasal swabs and lung tissue from each individual, a total of 13 (10.4%) animals scored positive for yeasts, 7 for Cryptococcus neoformans (C.n.) (5.6%) and 6 for other yeasts (4.8%). C.n. was isolated from the nostrils and lungs, with a high population size in nostrils. Two C.n. molecular types, VNI and VNIV, were identified, with C.n. var. grubii VNI the most prevalent. Phylogenetic analyses of ITS+ and URA5 sequences revealed that C.n. isolates were genetically similar to isolates from a range of geographical areas and hosts. Results suggest that C.n. can colonize or infect the respiratory tract of C. finlaysonii. The high occurrence and level of colonization of nasal cavities might be an indicator of environmental exposure to high levels of airborne microorganism. The close phylogenetic relationship of C.n. strains from squirrels with those from human and other animal hosts suggests a potential role for these animals as "sentinels" for human exposure.

Anti-infective prophylaxis in pediatric patients with acute myeloid leukemia

Pediatric patients undergoing treatment for acute myeloid leukemia (AML) are at high risk for infectious complications, predominantly due to Gram-negative bacteria, viridans group streptococci and fungal pathogens. In order to prevent infections in these patients, most institutions have implemented a number of non-pharmacological approaches to supportive care. In addition, antibiotic prophylaxis reduces bacterial infection, but may increase the emergence of resistance. Antifungal prophylaxis is generally recommended for children with AML. Whereas the use of hematopoietic growth factors has not resulted in improved survival, the efficacy of prophylactic granulocyte transfusions has to be determined.

Predictors and outcomes of viridans group streptococcal infections in pediatric acute myeloid leukemia: from the Canadian infections in AML research group

BACKGROUND

Viridans group streptococci (VGS) cause significant morbidity in children treated for acute myeloid leukemia (AML). Our goals were to determine the occurrence and impact of these infections in children treated for AML and to understand the factors that increase the risk of VGS infections and viridans streptococcal shock syndrome (VSSS) in this population.

METHODS

We conducted a retrospective, population-based cohort study that included children ≤18 years of age with de novo AML treated at 15 Canadian centers. We evaluated factors related to VGS infection and VSSS.

RESULTS

Among 341 children with AML, VGS occurred in 78 (22.9%) children over the entire course of therapy and 16 had recurrent episodes. VGS infection occurred in 97 of 1277 courses of chemotherapy (7.6%). VSSS occurred in 19.6% of these episodes and included 11 patients who required intensive care services with 2 VGS infections resulting in death. In multiple regression analysis, factors independently related to VGS included treatment on a Medical Research Council-based protocol (odds ratio (OR) 2.87, 95% confidence interval (CI) 1.53-5.39; P = 0.001), cytarabine dose per gram/m² (OR 1.04, 95% CI 1.01-1.07; P = 0.002) and prolonged neutropenia (OR 1.58, 95% CI: 0.97-2.56; P = 0.06). None of the evaluated factors were predictive of VSSS.

CONCLUSIONS

VGS infections occur in 7.6% of chemotherapy courses and remain an important cause of morbidity and even mortality in children being treated for AML. Interventions to reduce VGS need to be identified.