Breakthrough filamentous fungal infections in pediatric hematopoetic stem cell transplant and oncology patients receiving caspofungin

The clinical impact of primary granulocyte-colony stimulating factor prophylaxis in children with acute lymphoblastic leukemia who underwent induction chemotherapy

BACKGROUND

Data describing the risk factors for the occurrence of severe infections in acute lymphoblastic leukemia (ALL) patients following induction chemotherapy and the role of prophylactic granulocyte-colony stimulating factor (G-CSF) in the era of antimicrobials prophylaxis are limited.

METHODS

This study enrolled 188 children aged ≤18 years with newly diagnosed ALL who received Taiwan Pediatric Oncology Group ALL-2002 and 2013 treatments between January 1, 2010 and June 30, 2021. Prophylactic G-CSF was administered when a patient continues neutropenia after achieving the first bone marrow remission since June 1, 2015. Clinical factors were assessed for their association with severe infections.

RESULTS

From January 2010 to May 2015, 80 children experienced a total of 11 (13.5%) episodes of severe infections; while 10 (9.2%) episodes were reported to occur in 108 patients who received prophylactic G-CSF. Reduction of severe infections occurrence did not achieve statistical significance during prophylactic G-CSF administration in ALL patients. Compared with ALL-high risk (HR) and very high risk patients with no G-CSF prophylaxis, the use of G-CSF prophylaxis significantly reduced episodes of febrile neutropenia. Occurrence of grade III-IV intestinal ileus, grade II-III oral mucositis, prolonged neutropenia, central venous catheter (CVC) placement, or the requirement insulin therapy for hyperglycemia were associated with higher risk of bloodstream infections.

CONCLUSIONS

ALL-HR patients with G-CSF prophylaxis were associated with reduction of febrile neutropenia episodes. Occurrence of severe ileus, oral mucositis, hyperglycemia, CVC placement, or prolonged neutropenia were associated with severe infections in ALL patients receiving induction chemotherapy.

Role of Antifungal Prophylaxis in Invasive Fungal Infection in Children with Acute Lymphoblastic Leukemia—A Retrospective Cross-Sectional Study

Introduction Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Its outcome in India is not as good as that in the western world. One of the important reasons for lesser survival rates is opportunistic infections, including invasive fungal infections (IFIs). Antifungal prophylaxis (AFP) in ALL children is routinely not followed. However, owing to its incidence in high-risk ALL, this study is focused on the use of AFP in those children.

Objectives This retrospective study investigated the role of AFP in newly diagnosed children with high-risk ALL on intensive blocks of therapy on regimens B and C of the United Kingdom Acute Lymphoblastic Leukemia 2003 protocol.

Materials and Methods The study was conducted in a tertiary care center from 1st December 2013 to 31st December 2019 and included children with ALL from 1 to 18 years of age. Routine AFP with voriconazole was commenced for high-risk ALL children from 1st July 2017 onward in our center. We analyzed data of all IFIs in children before and after AFP with National Cancer Institute high-risk status who had been started on regimen B induction and regimen B or C consolidation and intensification phases.

Results A total of 55 children with high-risk ALL were included in the study. The median age was 4 years, with the majority being between the age of 1 and 10 years (38 out of 55; 65%) and predominantly male (36 out of 55; 69%). Total incidence of IFI in our cohort was 51% (28 out of 55). A significant number of children (16 out of 22 [70%]) who were not on prophylaxis developed IFI versus children (12 out of 33 [28%]) on prophylaxis (p = 0.008). The most common organisms isolated were Candida parapsilosis and Candida tropicalis. Children not receiving AFP were found to be 4.7 times (95% confidence interval: 1.44–15.13) more likely to get IFI than the ones receiving AFP. The presence of concurrent bacterial infection increases the risk of IFI (p = 0.04).

Conclusion The incidence of IFI was high in high-risk ALL children who were not on AFP. The introduction of routine AFP reduced the incidence of IFI.

Novel Insights into Fungal Infections Prophylaxis and Treatment in Pediatric Patients with Cancer

Invasive fungal diseases (IFDs) are a relevant cause of morbidity and mortality in children with cancer. Their correct prevention and management impact patients’ outcomes. The aim of this review is to highlight the rationale and novel insights into antifungal prophylaxis and treatment in pediatric patients with oncological and hematological diseases. The literature analysis showed that IFDs represent a minority of cases in comparison to bacterial and viral infections, but their impact might be far more serious, especially when prolonged antifungal therapy or invasive surgical treatments are required to eradicate colonization. A personalized approach is recommended since pediatric patients with cancer often present with different complications and require tailored therapy. Moreover, while the Aspergillus infection rate does not seem to increase, in the near future, new therapeutic recommendations should be required in light of new epidemiological data on Candidemia due to resistant species. Finally, further studies on CAR-T treatment and other immunotherapies are needed in patients with unique needs and the risk of complications. Definitive guidelines on IFD treatment considering the evolving epidemiology of antifungal resistance, new therapeutic approaches in pediatric cancer, novel antifungal drugs and the importance of an appropriate antifungal stewardship are urgently needed.

Rhizomucor pusillus Infection in a Patient with Acute Myeloid Leukaemia After Haematopoietic Stem Cell Transplantation: Clinical Impact of Metagenomics Next-Generation Sequencing

Long-term chemotherapy and immunosuppressants in acute myeloid leukaemia (AML) patients can result in a high risk of opportunistic infections. Rhizomucor pusillus is an opportunistic pathogen that exists in nature, but infection caused by R. pusillus is rare in the clinic. Notably, the sensitivity and detection time of conventional diagnostic tools for this fungus usually falls short of the needs of clinical diagnosis, resulting in treatment failure. Currently, metagenomics next-generation sequencing (mNGS) has played an important role in the detection of pathogens. Here, we report a case of R. pusillus pneumonia in a haematopoietic stem cell transplantation (HSCT) patient, detected by the mNGS method.

A Survival Analysis of Invasive Fungal Diseases in Children with Cancer

Objective This study aimed to determine the survival in a retrospective cohort of 152 patients treated for invasive fungal diseases (IFD) (133 proven and 19 probable) in 9 years.

Methods Our study included patients aged 0 to 18 years diagnosed with cancer at our institution and with proven or probable IFD, treated from 2011 to 2019. Weibull distribution was used for hazard ratios and accelerated failure time models for the outcome “death attributed to IFD.”

Results Our median age was 97 months. The most frequent diagnosis was leukemia (39, 25.7%). A total of 37 patients received prophylaxis with fluconazole (24.3%). Among 133 fungal isolates, the most frequent were Candida species in blood 81 (53.2%). Moreover, 43 deaths were attributed to IFD (28.3%). Survival probabilities were lower for pulmonary IFD (46.9%, p = 0.0017), leukemia (62.5%, p = 0.004), and neutropenia <500 cells/mm3 (55.4%, p < 0.0001). For Candida fungemia, survival probabilities were 76.6% (p = 0.043). In Weibull models, the diagnosis of leukemia shortened survival times by a factor of 0.006, relapse of disease by 0.05, lymphoma by 0.04, pulmonary IFD by 0.04, and neutropenia by 0.015. Hematopoietic stem cell transplantation did not affect the survival times as well as prophylaxis with fluconazole.

Conclusion Host factors, such as neutropenia, relapse of disease, and hematologic malignancies, are determinants in the survival times of children with IFD as well as pulmonary involvement.

[Fungal infection in immunocompromised children]

In recent years, immunodeficiency condition has experienced a rise among children, who are at risk of invasive fungal infections (IFI) due to their health condition. Cancer, non-malignant hematological diseases, as primary immunodeficiencies, hematopoietic stem cell transplantation (HSCT), extreme prematurity, or critically ill condition in Pediatric Intensive Care Unit (PICU) are some immunosuppressive situations in children. The use of oncologic therapies, including immunotherapy and monoclonal antibodies, for the treatment of the aforementioned health conditions has led to an increase in morbidity and mortality rates of IFI in children. The underlying diseases and their management, comorbidities, the diagnostic tests used (both molecular and imaging), as well as the treatment used can be significantly different between adult patients and children admitted to PICU or with cancer. In pediatrics, the treatment of IFI is based primarily on pharmacokinetic studies performed in adults. In higher risk patients prophylaxis should be considered and, in the case of an IFI diagnosis, an antifungal treatment should be administered as early as possible, supported by the reversion of the immune dysfunction and surgery when appropriate.

Fulminant Rhizomucor pusillus mucormycosis during anti-leukemic treatment with blinatumomab in a child: A case report and review of the literature

This is the first published case report of a child with acute lymphatic leukemia developing a fatal mucormycosis during blinatumomab treatment. The patient showed multiple, systemic thromboembolic lesions with ischemia, bleeding and infarction in almost all organs. The child succumbed to increased brain pressure resulting in cerebral herniation. This case particularly illustrates the fulminant progression and huge challenges of diagnosing and treating mucormycosis in children with hemato-oncological diseases during treatment with targeted therapeutic antibodies (blinatumomab).

Infections Caused by Fusarium Species in Pediatric Cancer Patients and Review of Published Literature

Fusarium species have emerged as responsible for a broad spectrum of infections, including superficial, locally invasive and disseminated ones, especially in the hospital environment. Since there are few reports of invasive and disseminated fusariosis in children, the aim of this study was to report four cases of nosocomial infection caused by this microorganism in children with cancer hospitalized in a public children's hospital located in Brazil. Two of these patients were female and two were male. All patients presented febrile neutropenia, while three patients had acute lymphocytic leukemia and one patient had Wilms' tumor as underlying disease. In two cases, fungi were isolated from blood and identified as Fusarium oxysporum species complex after phenotypic and genotypic studies, while in two other cases fungi were isolated from skin biopsies and identified as Fusarium solani species complex. One patient died 12 days after the onset of cutaneous lesions. All isolates, after susceptibility testing, presented high levels of minimum inhibitory concentration for itraconazole, voriconazole and amphotericin B. Considering the emergence of filamentous fungi as etiologic agents of nosocomial infections, health professionals should be aware of the problems these infections, especially fungal ones, may cause to debilitated patients.

The current treatment landscape: other fungal diseases (cryptococcosis, fusariosis and mucormycosis)

Compared with major invasive mycoses such as aspergillosis and candidiasis, the antifungal stewardship management strategies of other fungal diseases have different opportunities and considerations. Cryptococcosis, fusariosis and mucormycosis are globally prevalent invasive fungal diseases (IFDs), but are not currently included in antifungal prophylaxis guidelines for immunocompromised hosts. Since the implementation of biomarkers as part of diagnostic screening strategies, the concept of pre-emptive antifungal therapy has emerged for these IFDs. Management of cryptococcosis, the most common IFD worldwide, generally utilizes a pre-emptive or therapeutic strategy that does not involve prophylaxis or empirical antifungal treatment strategies. Antifungal stewardship outcomes for cryptococcosis may vary according to the availability of local resources. Invasive fusariosis, the second-most common form of non-Aspergillus mould infection among haematological malignancy patients, can be managed with pre-emptive (or diagnostic-driven) approaches based on the monitoring of serum galactomannan (GM) antigen in increased-risk populations. The success of antimicrobial stewardship programmes in decreasing the burden of invasive fusariosis in selected patient populations depends on the development and implementation of rapid diagnostic strategies for early and appropriate administration of therapy. Mucormycosis may emerge as a breakthrough IFD in haematology or solid organ transplant recipients receiving antifungals that lack activity against Mucorales. The concept of pre-emptive antifungal therapy has thus arisen for mucormycosis in the haematology setting because of the recent availability of circulating Mucorales DNA measurement. These examples demonstrate the challenges of implementing antifungal stewardship programmes in areas with limited resources, as well as in IFDs that are difficult to diagnose and treat.

Use of Fungal Diagnostics and Therapy in Pediatric Cancer Patients in Resource-Limited Settings

Fungal diseases are an important cause of mortality in immunocompromised hosts, and their incidence in pediatric cancer patients in low- to middle-income countries is underestimated. In this review, we present relevant, up-to-date information about the most common opportunistic and endemic fungal diseases among children with cancer, their geographic distribution, and recommended diagnostics and treatment. Efforts to improve the care of children with cancer and fungal disease must address the urgent need for sustainable and cost-effective solutions that improve training, fungal disease testing capability, and the use of available resources. We hope that the collective information presented here will be used to advise healthcare providers, regional and country health leaders, and policymakers of the current challenges in diagnosing and treating fungal infections in children with cancer in low- to middle-income countries.

A Prospective, International Cohort Study of Invasive Mold Infections in Children

BACKGROUND

Invasive mold infections (IMIs) are a leading cause of mortality in immunocompromised children, yet there has never been an international epidemiologic investigation of pediatric IMIs.

METHODS

This international, prospective cohort study was performed to characterize the epidemiology, antifungal therapy, and outcomes of pediatric IMIs. Children (≤18 years) with proven or probable IMIs were enrolled between August 2007 and May 2011 at 22 sites. Risk factors, underlying diagnoses, and treatments were recorded. Outcomes were assessed at 12 weeks after diagnosis using European Organization for Research and Treatment of Cancer/Mycoses Study Group response criteria.

RESULTS

One hundred thirty-one pediatric patients with IMIs were enrolled; the most common IMI was invasive aspergillosis ([IA] 75%). Children with IA and those with other types of IMIs had similar underlying risk factors, except that children with IMIs caused by non-Aspergillus species were more likely to have received mold-active antifungal agents preceding diagnosis. The most commonly used antifungal classes after diagnosis were triazoles (82%) and polyenes (63%). Combination therapy was used in 53% of patients. Use of combination therapy was associated with an increased risk of adverse events (risk ratio, 1.98; 95% confidence interval, 1.06-3.68; P = .031), although there was no detectable difference in outcome.

CONCLUSIONS

Although risk factors for IMIs are similar across specific subtypes, preceding antifungal therapy may be an important modifier. Combination antifungal therapy requires further study to determine its true risks and benefits.

Caspofungin Treatment of Aspergillus fumigatus Results in ChsG-Dependent Upregulation of Chitin Synthesis and the Formation of Chitin-Rich Microcolonies

Treatment of Aspergillus fumigatus with echinocandins such as caspofungin inhibits the synthesis of cell wall β-1,3-glucan, which triggers a compensatory stimulation of chitin synthesis. Activation of chitin synthesis can occur in response to sub-MICs of caspofungin and to CaCl₂ and calcofluor white (CFW), agonists of the protein kinase C (PKC), and Ca²⁺-calcineurin signaling pathways. A. fumigatus mutants with the chs gene (encoding chitin synthase) deleted (ΔAfchs) were tested for their response to these agonists to determine the chitin synthase enzymes that were required for the compensatory upregulation of chitin synthesis. Only the ΔAfchsG mutant was hypersensitive to caspofungin, and all other ΔAfchs mutants tested remained capable of increasing their chitin content in response to treatment with CaCl₂ and CFW and caspofungin. The resulting increase in cell wall chitin content correlated with reduced susceptibility to caspofungin in the wild type and all ΔAfchs mutants tested, with the exception of the ΔAfchsG mutant, which remained sensitive to caspofungin. In vitro exposure to the chitin synthase inhibitor, nikkomycin Z, along with caspofungin demonstrated synergistic efficacy that was again AfChsG dependent. Dynamic imaging using microfluidic perfusion chambers demonstrated that treatment with sub-MIC caspofungin resulted initially in hyphal tip lysis. However, thickened hyphae emerged that formed aberrant microcolonies in the continued presence of caspofungin. In addition, intrahyphal hyphae were formed in response to echinocandin treatment. These in vitro data demonstrate that A. fumigatus has the potential to survive echinocandin treatment in vivo by AfChsG-dependent upregulation of chitin synthesis. Chitin-rich cells may, therefore, persist in human tissues and act as the focus for breakthrough infections.

An outbreak of invasive fusariosis in a children's cancer hospital

Fusarium is considered an emerging pathogen, and there are few reports of fusariosis in children. The objective of this study was to describe an outbreak of invasive fusariosis in a children's cancer hospital. A neutropenic 17-year-old male patient hospitalized for 10 days for a relapse of acute myeloid leukaemia, under chemotherapy, presented fever without any other symptoms; a thoracic computerized tomography showed bilateral pulmonary nodules. During voriconazole treatment, 1-cm reddened and painful subcutaneous nodules appeared on arms and legs and the culture of a skin biopsy revealed F. solani. Another case occurred 11 days later and started an outbreak investigation. Water samples for cultures were collected from taps, showers and water reservoirs. Air from all patient rooms was sampled. Faucets and the drains of sinks and showers were swabbed and cultured. Environmental and clinical isolates were typed. There were 10 confirmed cases of infection caused by Fusarium spp. F. oxysporum and F. solani were isolated from water, swabs and air in patient rooms. Many control measures were instituted, but the outbreak was only controlled 1 year after the first case, when water filters filtering 0.2 μm were installed at the exit of all faucets and showers in all patient rooms (points-of-use). Typing demonstrated that clinical isolates of F. oxysporum were similar to those of the environment. In conclusion, to our knowledge this is the first reported outbreak of invasive fusariosis in children with oncohaematologic disease. It was controlled using 0.2-μm filters in all tap faucets and showers.