Clinical and microbiological characteristics of proven invasive aspergillosis due to rare/cryptic species in allogeneic hematopoietic stem cell transplant recipients

Is neutropenia still the main risk factor for invasive aspergillosis? A contemporary university hospital retrospective cohort of invasive aspergillosis in neutropenic and non-neutropenic patients

INTRODUCTION

In times of mold active prophylaxis, invasive aspergillosis (IA) epidemiology is evolving. Presentation in non-neutropenic may differ from neutropenic. We investigated the cases of IA in our center with a focus on differences between neutropenic and non-neutropenic, and analyzed the impact of cryptic and non-fumigatus Aspergillus species.

METHODS

Retrospective observational study including all adult patients admitted to the Puerta de Hierro-Majadahonda Hospital between January 2018 and April 2024 with IA.

RESULTS

112 IA were identified. Only 11 (9.8%) had neutropenia as risk factor for IA. Most frequent risk factors were corticosteroids (77.2%), SOT (46.5%), SARS-CoV2 (29.7%) and CMV replication (28.7%). 89.3% were pulmonary IA with 6 cases (5.4%) of disseminated infection. A. fumigatus was the most frequent species 48 (51.6%). 13 cases (14%) were caused by cryptic Aspergillus spp. Non-neutropenic patients, compared to neutropenic patients, were more likely to have positive fungal cultures (83.2% versus 54.5%, p = 0.023[NS]), and not to present a halo sign (7.4% versus 45.5%, p = 0.003 [NS]). In addition, in non-neutropenic patients, compared to neutropenic patients, there was a trend towards a greater probability of positive GM from BAL (81.3% versus 66.7%, p = 0.304) and a trend towards a lower probability of positive serum GM (25.7% versus 45.5%, p = 0.137). 41/112 (36.6%) cases presented breakthrough IFI and in 51.2%, (21/41 cases), the isolate was resistant to the prior antifungal. One presented A. fumigatus with the TR34-L98H mutation.

CONCLUSION

Risk factors different than neutropenia are currently the most common in IA. The clinical presentation in non-neutropenic patients differs from neutropenic. Resistance to antifungals is emerging especially in breakthrough IA.

Invasive aspergillosis caused by cryptic species in transplant recipients: A review

The clinical and microbiological characteristics of invasive aspergillosis (IA) caused by cryptic Aspergillus species have not been well-defined in transplant settings. However, IA is among the most common mould infections in solid organ and hematopoietic stem cell transplant recipients. Among 55 causative isolates in the 53 reported cases, Aspergillus calidoustus, A. lentulus, A. tubingensis, and A. udagawae were the four most common causative cryptic Aspergillus species. Newer diagnostic modalities, such as matrix-assisted laser desorption ionization-time of flight mass spectrometry, may help diagnose these cryptic species. Of the 24 cases with detailed clinical information, 13 had antifungal breakthrough infections. The 12-week mortality rates of all 24 cases, 7 cases of A. calidoustus, and 7 cases of A. lentulus were 46%, 43%, and 43%, respectively. Based on antifungal susceptibility profiles obtained from previous studies, an empiric antifungal regimen such as liposomal amphotericin B with or without echinocandin is recommended for A. calidoustus. A combination of an anti-mould azole and liposomal amphotericin B with or without an echinocandin is suggested for A. lentulus and A. udagawae. Additionally, any one of voriconazole, isavuconazole, or posaconazole with or without liposomal amphotericin B with or without an echinocandin is indicated for A. tubingensis. Newer antifungal agents may have more significant activity against Aspergillus cryptic species.

MicroRNAs in infectious diseases: potential diagnostic biomarkers and therapeutic targets

MicroRNAs (miRNAs) are conserved, short, non-coding RNAs that play a crucial role in the post-transcriptional regulation of gene expression. They have been implicated in the pathogenesis of cancer and neurological, cardiovascular, and autoimmune diseases. Several recent studies have suggested that miRNAs are key players in regulating the differentiation, maturation, and activation of immune cells, thereby influencing the host immune response to infection. The resultant upregulation or downregulation of miRNAs from infection influences the protein expression of genes responsible for the immune response and can determine the risk of disease progression. Recently, miRNAs have been explored as diagnostic biomarkers and therapeutic targets in various infectious diseases. This review summarizes our current understanding of the role of miRNAs during viral, fungal, bacterial, and parasitic infections from a clinical perspective, including critical functional mechanisms and implications for their potential use as biomarkers and therapeutic targets.

Changes in fungal taxonomy: mycological rationale and clinical implications

Numerous fungal species of medical importance have been recently subjected to and will likely continue to undergo nomenclatural changes as a result of the application of molecular approaches to fungal classification together with abandonment of dual nomenclature. Here, we summarize those changes affecting key groups of fungi of medical importance, explaining the mycological (taxonomic) rationale that underpinned the changes and the clinical relevance/importance (where such exists) of the key nomenclatural revisions. Potential mechanisms to mitigate unnecessary taxonomic instability are suggested, together with approaches to raise awareness of important changes to minimize potential clinical confusion.

IFISTRATEGY: Spanish National Survey of Invasive Fungal Infection in Hemato-Oncologic Patients

Recent advances in the treatment of hematologic malignancies have improved the overall survival rate, but the number of patients at risk of developing an invasive fungal infection (IFI) has increased. Invasive infections caused by non-Candida albicans species, non-Aspergillus molds, and azole-resistant Aspergillus fumigatus have been increasingly reported in recent years. We developed a cross-sectional multicenter survey which involved a total of 55 hematologists and infectious disease specialists from a total of 31 Spanish hospitals, to determine the most frequent strategies used for the management of IFIs. Data collection was undertaken through an online survey which took place in 2022. Regarding key strategies, experts usually prefer early treatment for persistent febrile neutropenia, switching to another broad-spectrum antifungal family if azole-resistant Aspergillus is suspected, broad-spectrum azoles and echinocandins as prophylactic treatment in patients receiving midostaurin or venetoclax, and liposomal amphotericin B for breakthrough IFIs after prophylaxis with echinocandins in patients receiving new targeted therapies. For antifungals failing to reach adequate levels during the first days and suspected invasive aspergillosis, the most appropriate strategy would be to associate an antifungal from another family.

Case Commentary: Long-term fosmanogepix use in a transplant recipient with disseminated aspergillosis caused by azole-resistant Aspergillus calidoustus

Aspergillus calidoustus is an emerging, azole-resistant, cryptic Aspergillus species in immunosuppressed patients that often features extrapulmonary involvement and carries high mortality. The case presented by J. F. Camargo, R. Jabr, A. D. Anderson, L. Lekakis, et al. (Antimicrob Agents Chemother 66:e02206-21, 2022, https://doi.org/10.1128/aac.02206-21 ) describes a transplant recipient with disseminated A. calidoustus infection who was successfully treated with surgical source control, tapering of immunosuppression, and long-term, combination antifungal treatment that included the first-in-class fosmanogepix, which targets fungal mannoprotein trafficking and anchoring.

Successful treatment of disseminated disease due to highly resistant Aspergillus calidoustus with a novel antifungal therapy

Invasive aspergillosis is the most common invasive mold infection following a hematopoietic cell transplant. Widespread use of antifungal prophylaxis has led to increasing incidence of cryptic Aspergillus species. Aspergillus calidoustus is one of those emerging species and is notorious for multidrug resistance to antifungals. Here we report a case of disseminated A. calidoustus infection in a hematopoietic stem cell transplant recipient, who was successfully treated with combination therapy that included a novel antifungal.