COVID-19 associated mucormycosis surge: A review on multi-pathway mechanisms

Mucormycosis is a fungal infection caused by moulds from the Mucorales order. Concerns have been mounting due to the alarming increase in severe morbidity and mortality associated with mucormycosis during the COVID-19 pandemic. This condition, known as COVID-19-associated mucormycosis (CAM), has been linked to various environmental, host-related, and medical factors on a global scale. We have categorized the most significant potential risk factors for developing mucormycosis in individuals with a previous history of coronavirus infection into 10 major categories. These categories include acute hyperglycemia, the impact of cytokine release, immune response deficiencies in COVID-19 patients, microvasculopathy and dysfunction of endothelial cells, imbalances in iron metabolism, metabolic acidosis, organ damage resulting from COVID-19, underlying health conditions (such as diabetes), environmental factors, and medical treatments that can be iatrogenic in nature (such as inappropriate glucocorticoid use). Many of these factors can lead to potentially life-threatening infections that can complicate the treatment of COVID-19. Physicians should be vigilant about these factors because early detection of mucormycosis is crucial for effective management of this condition.

Breakthrough invasive fungal infections: Who is at risk?

The epidemiology of invasive fungal infections (IFIs) in immunocompromised individuals has changed over the last few decades, partially due to the increased use of antifungal agents to prevent IFIs. Although this strategy has resulted in an overall reduction in IFIs, a subset of patients develop breakthrough IFIs with substantial morbidity and mortality in this population. Here, we review the most significant risk factors for breakthrough IFIs in haematology patients, solid organ transplant recipients, and patients in the intensive care unit, focusing particularly on host factors, and highlight areas that require future investigation.

MALDI-TOF MS for the rapid identification and drug susceptibility testing of filamentous fungi

The present study aimed to evaluate the applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identifying filamentous fungi and assessing the in vitro activities of common antifungal drugs against different kinds of filamentous fungi that are commonly encountered in a clinical setting. A total of 123 strains of filamentous fungi (24 species) were submitted for identification by MALDI-TOF MS, and the findings were compared with those obtained by conventional methods. The discrepancies were further investigated by internal transcribed spacer (ITS) sequence analysis. Then, 79 strains were randomly selected for further testing by the minimum inhibitory concentration Etest method. MALDI-TOF MS correctly identified 114 (92.70%) of the 123 filamentous fungi and failed to identify six isolates (4.9%). By contrast, the conventional identification methods made 113 (91.9%) correct identifications. In addition, 15 isolates of filamentous fungi were further identified by ribosomal DNA-ITS sequencing. In the in vitro antifungal susceptibility test, voriconazole showed the strongest antifungal activity among the tested drugs against a broad range of filamentous fungi. Caspofungin showed a better in vitro antifungal activity than fluconazole, itraconazole, and amphotericin B. MALDI-TOF MS offers a cost/time-saving, high-throughput and accurate working protocol for identifying filamentous fungi. Voriconazole could still serve as the first-line drug for treating serious infections caused by filamentous fungi, while caspofungin may be another treatment option for fungal infections.

Auditing fungal disease in leukemia patients in a tertiary care center: opportunities and challenges for an antifungal stewardship program

Invasive fungal disease (IFD) is responsible for significant morbidity and mortality in patients with acute leukemia. Antifungal stewardship (AFS) programs are utilized in this patient group but have been infrequently evaluated in clinical practice. Adults diagnosed with acute leukemia at an Australian tertiary center over two years were identified, with subsequent auditing of IFD prophylaxis and treatment, and identification of further opportunities for AFS activities. Proven or probable IFD occurred in 6% of cases, including 14% of acute lymphoblastic leukemia (ALL) patients and 6% of acute myeloid leukemia (AML) patients. Mold-active antifungal prophylaxis was used in 84% of cases overall, including in 94% of AML cases and 23% of ALL cases. Local auditing identified target areas for AFS in this complex patient cohort, including modification of clinical guidelines, enhanced patient screening, improved access to fungal diagnostics and therapeutic drug monitoring, and the establishment of a specialized, embedded AFS program.

Systemic Antifungal Prophylaxis in Patients Hospitalized in Hematology Units in France: The AFHEM Cross-Sectional Observational Study

INTRODUCTION

The frequency of invasive fungal diseases (IFDs) has increased in recent years. Within a context where both treatments and guidelines are fast evolving, we aim to shed new light on IFD management in hematologic departments in France.

METHODS

A multicenter cross-sectional observational study was prospectively conducted in 24 French centers in September and October 2013.

RESULTS

Four hundred ninety-four hospitalized children and adult patients suffering from hematologic malignancy were enrolled: 147 (30%) were allogeneic hematopoietic stem cell transplant (HSCT) recipients, 131 (27%) were patients with acute myeloblastic leukemia or myelodysplastic syndrome (MDS), 71 (14%) were patients with acute lymphoblastic leukemia who did not undergo allogeneic HSCT, and the 145 (29%) remaining patients did not belong to the three above groups. Two hundred forty-six patients (50%) received antifungal treatment, which was prophylactic in 187 (76%) treated patients. These rates were similar across all groups (63-80%). Patients received prophylaxis with an azole (79%), intravenous amphotericin B formulation (10%), echinocandin (9%), or two combination drugs (2%).

CONCLUSION

Results indicate that prophylaxis is the leading antifungal strategy in French hematology units, regardless of the disease condition, representing 76% of prescriptions for antifungal therapy.

FUNDING

Astellas Pharma France.

Glucose-6-phosphate dehydrogenase deficiency and risk of invasive fungal disease in patients with acute myeloid leukemia

Invasive fungal diseases (IFD) are still a leading cause of morbidity and mortality in patients with acute myeloid leukemia (AML). Glucose-6-phosphate dehydrogenase is an enzyme that leads to the production of NADPH, required to destroy microorganisms in the respiratory burst reaction of white blood cells. We evaluated the role of G6PD deficiency in susceptibility of IFD in 108 AML patients undergoing intensive chemotherapy. In all, 28 patients harbored G6PD deficiency (G6PD-), whereas 80 were normal (G6PD +). Incidence of IFD was significantly higher in G6PD- patients compared to G6PD + patients (35.7% vs. 5%, p = .0002, OR = 10, 95% CI = 2.96-37.5). Higher risk of mold infections (17.9% vs. 5%, p = .048, OR = 4.1, 95% CI = 1.0-16.6) and Candida sepsis (17.9% vs. 0%, p = .0009, OR = 37.68, 95% CI =2.0-707.1) was observed in G6PD - patients. The evaluation of G6PD activity may help to identify AML patients at higher risk of IFD, allowing to design more intensive surveillance and therapeutic strategies.

Risk factors and prophylaxis against invasive fungal disease for haematology and stem cell transplant recipients: an evolving field

INTRODUCTION

Due to increasing intensity and complexity of therapies and longer survivorship, many patients with haematologic malignancy (HM) are at risk of invasive fungal disease (IFD). Mortality from IFD is high and treatment of an episode of IFD results in an excess length of hospital stay and costs and delays delivery of curative therapy of the underlying haematologic condition. Therefore, prevention and early recognition and treatment of IFD are crucial. Areas covered: Risk factors particular to certain HMs and haematopoietic stem cell transplantation, as well as those risk factors universal to all HM groups are examined. Expert commentary: Risk stratification identifies those patients who would benefit most from mould active versus yeast active prophylaxis and those who can be safely managed with monitoring and clinically driven interventions for IFD. This approach aids in antifungal stewardship.

Evaluation of invasive aspergillosis risk of immunocompromised patients alternatively hospitalized in hematology intensive care unit and at home

Contrary to hospital exposure, little is known about the indoor fungal exposure of hematology patients at home. The aim of our study was to investigate the mold exposure of hematology patients both at home and at hospital to assess their invasive aspergillosis (IA) risk. Fungal exposure was assessed by quantifying opportunistic molds at hospital during hospitalization and in homes of 53 hematology patients. IA was diagnosed in 13 of 53 patients and invasive fungal infection (IFI) in one patient. In hospital, no opportunistic species, or low levels of opportunistic species, were found in 98% of weekly controls. Only 2% of hematology intensive care unit (ICU) controls showed a high level of Aspergillus fumigatus spores in corridor air. Five patients IA were hospitalized during these periods. Seven dwellings of 53 (5/14 dwellings of patients with IA/IFI and 2/39 dwellings of non-IA patients) had a percentage of A. fumigatus and Aspergillus flavus to total mold (significant predictor variable of IA/IFI in our study, general linear model, P-value = 0.02) as high as 15%. Maintaining a 'zero Aspergillus' goal at hospital is essential, and establishing specific and individually opportunistic mold monitoring at home could help to further reduce the IA risk through continuous surveillance.

PRACTICAL IMPLICATIONS

This study emphasizes the fact that preventive measures should not be aimed only at the hospital setting: among patients diagnosed with invasive aspergillosis/invasive fungal infection (IA/IFI), 5 of 14 (36%) were exposed to opportunistic fungal species at home exclusively. Moreover, four of these five patients were living in homes having the highest percentage of Aspergillus fumigatus and Aspergillus flavus (>15%), one of which had 48% of A. fumigatus. Therefore, our work supports the need for a counselor to carry out an environmental survey in patients’ homes.