Treatment principles for the management of mold infections

Clinical manifestations and susceptibility of Scedosporium/Lomentospora infections at a tertiary medical centre in Taiwan from 2014 to 2021: A retrospective cohort study

BACKGROUND

Scedosporiosis/lomentosporiosis is a globally emerging and crucial fungal infection. However, clinical data on Scedosporium/Lomentospora infections in Taiwan are scarce.

OBJECTIVES

This study aimed to explore the clinical characteristics of Scedosporium/Lomentospora-infected patients and evaluate the susceptibility of these isolates to antifungal agents.

METHODS

The clinical features of Scedosporium/Lomentospora-infected patients at a tertiary teaching hospital in Northern Taiwan between 2014 and 2021 were retrospectively reviewed; isolates from these patients were identified to species level for antifungal susceptibility testing.

RESULTS

Among 44 patients, 27 (61.4%) had scedosporiosis/lomentosporiosis, whereas 17 (38.6%) were colonised with Scedosporium/Lomentospora species. Scedosporium apiospermum was the main coloniser; scedosporiosis was primarily caused by S. boydii. Trauma history, steroid and immunosuppressant use were the most common risk factors for developing these infections. Among 27 patients with scedosporiosis/lomentosporiosis, one was lost to follow-up and seven (7/26, 26.9%) died. Most patients with S. apiospermum infection have a history of trauma, leading to cutaneous, bone and ocular infections. Pulmonary, sinus and disseminated infections and mortality were frequently reported in patients with S. boydii infection. Voriconazole's minimum inhibitory concentration was low for S. boydii, S. apiospermum and S. aurantiacum. Caspofungin, micafungin and anidulafungin were active against S. boydii and S. apiospermum. A potentially novel Scedosporium species was identified in this study, with distinct clinical manifestations and antifungal susceptibility.

CONCLUSIONS

At our centre, S. boydii is the main causative species of scedosporiosis; voriconazole could be the first-line treatment in Taiwan. Our study supports the importance of speciation, rather than only categorising these isolates into S. apiospermum species complex.

Invasive fungal infections in hematologic malignancies: Incidence, management, and antifungal therapy

The incidence of invasive fungal infections (IFIs) has increased in recent years as a result of increasing the incidence of hematologic malignancies (HMs). IFIs, as the opportunistic diseases, are the most important concern in these patients with a high mortality rate. These infections are one of the leading causes of morbidity and mortality in HM patients and an important factor in increasing the costs of patients' management because of the prolonged hospitalization and the inevitable need to use antifungal agents. Due to the changes in the pattern of organisms causing IFIs, unavailability of effective and safe antifungal drugs, and high rate of drug resistance as well as lack of fast and accurate diagnostic methods, these infections have become a serious and life-threatening problem necessitating effective prevention and treatment strategies using suitable antifungal agents, especially in high-risk patients. The aim of the present study was to review the pathogens causing various types of IFIs, diagnostic methods, and novel prophylactic and therapeutic antifungal regimens in HM patients according to the new published studies and clinical trials.

The Fragile Patient: Considerations in the Management of Invasive Mould Infections (IMIs) in India

Invasive mould infections (IMIs), which are mostly caused by Aspergillus spp. and Mucormycetes, are opportunistic infections that impose a substantial threat to patients who are considered to be 'fragile'. There is no fixed definition for fragile patients; however, patients with cancer or acquired immunodeficiency syndrome (AIDS), patients who have undergone organ transplants, and patients being treated in the intensive care units (ICUs) were considered fragile. Management of IMIs in fragile patients is challenging, owing to their compromised immune status. The diagnostic challenges associated with IMIs due to insufficient sensitivity and specificity of the current diagnostic tests lead to delayed treatment. A widening demographic of at-risk patients and a broadening spectrum of pathogenic fungi have added to the challenges to ascertain a definite diagnosis. A recent surge of mucormycosis associated with SARS-CoV-2 infections and the resultant steroid usage has been reported. Liposomal amphotericin B (L-AmB) is the mainstay for treating mucormycosis while voriconazole has displaced amphotericin B as the mainstay for treating Aspergillus infection due to its better response, improved survival, and fewer severe side effects. The selection of antifungal treatment has to be subjected to more scrutiny in fragile patients owing to their comorbidities, organ impairment, and multiple ongoing treatment modalities. Isavuconazole has been documented to have a better safety profile, stable pharmacokinetics, fewer drug-drug interactions, and a broad spectrum of coverage. Isavuconazole has thus found its place in the recommendations and can be considered a suitable option for treating fragile patients with IMIs. In this review, the authors have critically appraised the challenges in ascertaining an accurate diagnosis and current management considerations and suggested an evidence-based approach to managing IMIs in fragile patients.

Cell-free next-generation sequencing impacts diagnosis and antimicrobial therapy in immunocompromised hosts: A retrospective study

BACKGROUND

Cell-free next-generation sequencing (cfNGS) may have a unique role in the diagnosis of infectious complications in immunocompromised hosts. The rapid turnaround time and non-invasive nature make it a promising supplement to standard of care.

METHODS

This retrospective, observational single-center study at a tertiary care medical center in Virginia investigated the use of cfNGS in clinical practice. Patients over age 18 years with cfNGS performed for any indication were included. The primary outcome was detection of bacteria and/or fungi on cfNGS. The secondary outcomes were concordance, and abundance of fungal and bacterial organism concentration detected over time from symptom onset, and clinical impact.

RESULTS

Thirty-six patients (92% immunosuppressed) were identified and included. Twenty-one (58%) tests detected one to five organisms (14/21 bacteria, 8/21 fungi, and 6/21 viruses). The clinical impact of cfNGS was positive in 52.8% of cases, negative in 2.8%, and negligible in 44.4%. Positive tests prompted therapy changes in 12 of 21 patients; six of 20 bacteria and seven of eight fungi identified were considered clinically pathogenic. Three bacteria identifications and six fungi identifications prompted targeted treatment. When fungal species were not identified by cNFGS, antifungal de-escalation occurred in seven patients.

CONCLUSION

cfNGS assisted in critical management changes, including initiation of treatment for identified organisms and antimicrobial de-escalation. Its non-invasive nature and rapid turnaround time make this an important adjunct to standard of care testing that may assist in providing earlier, targeted therapy, especially when opportunistic pathogens remain high on the differential diagnosis.

Sanguinarine, Isolated From Macleaya cordata, Exhibits Potent Antifungal Efficacy Against Candida albicans Through Inhibiting Ergosterol Synthesis

In recent decades, infections caused by the opportunistic fungus Candida albicans have increased, especially in patients with immunodeficiency. In this study, we investigated the mechanism of action of sanguinarine (SAN) against C. albicans both in vitro and in vivo. SAN exhibited antifungal activity against C. albicans clinical isolates, with MICs in the range of 112.8-150.5 μM. Furthermore, scanning electron and transmission electron microscopy showed that SAN induced morphological changes as well as structure disruption in C. albicans cells, including masses of cellular debris, ruptured cell walls, and membrane deformation. Flow cytometry revealed that SAN could lead to cell membrane damage, and ergosterol content analysis indicated that SAN could cause ergosterol content reduction exceeding 90%. Further, we validated the efficacy of SAN against candidiasis caused by C. albicans in a murine model, and SAN significantly improved survival and reduced weight loss compared to vehicle. The treatment of 1.5 and 2.5 mg/kg/d SAN obviously reduced the fungal burden in the kidney. In addition, histopathological examination indicated that no fungal cells were observed in lung and kidney tissues after SAN treatment. Hence, this study suggests that SAN is a promising plant-derived compound for the development of an effective anticandidal agent.

Combination antifungal therapy for breakthrough invasive mould disease in patients with haematological malignancies: when management reasoning eclipses evidence-based medicine

Timely diagnosis and treatment of invasive mould disease is challenging in severely immunocompromised patients, particularly for patients who develop breakthrough infections while on antifungal prophylaxis. Currently, there are no high-quality data on how to best diagnose and treat these infections. Many essential decisions affecting the management of breakthrough mould disease are made before a definitive diagnosis is established. In this scenario, sound management reasoning often favours the use of combination antifungal therapy, especially when antifungal resistance, suspicion of undetected sites of infection or pharmacokinetic/pharmacodynamic limitations at the site of infection are likely. In these scenarios, pre-emptive use of antifungal combination therapy with frequent re-evaluation with an aim of de-escalation could be justified for many high-risk patients.

Resistance to Antifungal Drugs

Pathogenic fungi have several mechanisms of resistance to antifungal drugs, driven by the genetic plasticity and versatility of their homeostatic responses to stressful environmental cues. We critically review the molecular mechanisms of resistance and cellular adaptations of pathogenic fungi in response to antifungals and discuss the factors contributing to such resistance. We offer suggestions for the translational and clinical research agenda of this rapidly evolving and medically important field. A better understanding of antifungal resistance should assist in developing better detection tools and inform optimal strategies for preventing and treating refractory mycoses in the future.

Review of T-2307, an Investigational Agent That Causes Collapse of Fungal Mitochondrial Membrane Potential

Invasive infections caused by Candida that are resistant to clinically available antifungals are of increasing concern. Increasing rates of fluconazole resistance in non-albicans Candida species have been documented in multiple countries on several continents. This situation has been further exacerbated over the last several years by Candida auris, as isolates of this emerging pathogen that are often resistant to multiple antifungals. T-2307 is an aromatic diamidine currently in development for the treatment of invasive fungal infections. This agent has been shown to selectively cause the collapse of the mitochondrial membrane potential in yeasts when compared to mammalian cells. In vitro activity has been demonstrated against Candida species, including C. albicans, C. glabrata, and C. auris strains, which are resistant to azole and echinocandin antifungals. Activity has also been reported against Cryptococcus species, and this has translated into in vivo efficacy in experimental models of invasive candidiasis and cryptococcosis. However, little is known regarding the clinical efficacy and safety of this agent, as published data from studies involving humans are not currently available.

A real-world prospective observational study on the efficacy and safety of liposomal amphotericin B in 426 patients with persistent neutropenia and fever

INTRODUCTION

Invasive fungal diseases are crucial causes of morbidity and mortality among patients with febrile neutropenia (FN). Though liposomal amphotericin B (L-AMB) is one of the agents recommended for first-line empirical antifungal therapy in patients with FN, large-scale clinical studies have not been performed in Japan.

METHODS

An open-label prospective multi-center study was carried out to evaluate the safety and efficacy of L-AMB in Japanese patients with FN suspected of having fungal infection.

RESULTS

Of the 426 patients registered, safety and efficacy evaluations were conducted for 424 and 399, respectively. By clinical response criteria using 5 composite endpoints, the response rate was 46.6% (186/399). The response rate by age were 54.5% (child: 30/55), 47.5% (adult: 97/204), 42.1% (elderly: 59/140) respectively. Regarding the composite endpoints, resolution of fever was observed in 61.2% (244/399), no breakthrough fungal infection in 99.0% (395/399), survival for 7 days or longer after the completion of treatment in 83.7% (334/399), no discontinuation of treatment due to toxicity or lack of efficacy in 60.9% (243/399), and successful treatment of any baseline fungal infection in 10/18. Adverse drug reactions (ADRs) developed in 61.1% (259/424), and frequent ADRs were hypokalemia, kidney dysfunction, and liver dysfunction, as previously reported.

CONCLUSIONS

The safety and efficacy profile of L-AMB in Japanese patients with FN suspected of having fungal infection were elucidated for the first time, through the analysis of a large number of cases including pediatric patients under real-world clinical settings collected in this nationwide study.

Risk factors and mortality in invasive Rasamsonia spp. infection: Analysis of cases in the FungiScope® registry and from the literature

BACKGROUND

The new Rasamsonia spp. complex can develop invasive infection in immunosuppression or chronic pulmonary disease. It has potential to be misidentified as other genera due to morphological similarities. Nowadays, there is a gap of knowledge on this fungi.

OBJECTIVES

To provide knowledge base of risk factors and therapeutic decisions in invasive Rasamsonia spp. complex infection.

PATIENTS/METHODS

Cases of invasive infection due to Rasamsonia spp. (formerly Geosmithia/Penicillium spp.) from FungiScope^® registry and all reported cases from a literature were included.

RESULTS

We identified 23 invasive infections due to Rasamsonia spp., six (26.1%) in the FungiScope^® registry. Main risk factors were chronic granulomatous disease (n = 12, 52.2%), immunosuppressive treatment (n = 10, 43.5%), haematopoietic stem cell transplantation (n = 7, 30.4%), graft-versus-host disease and major surgery (n = 4, 17.4%, each). Predominantly affected organs were the lungs (n = 21, 91.3%), disease disseminated in seven cases (30.4%). Fungal misidentification occurred in 47.8% (n = 11), and sequencing was used in 69.6% of the patients (n = 16) to diagnose. Breakthrough infection occurred in 13 patients (56.5%). All patients received antifungal treatment, mostly posaconazole (n = 11), caspofungin (n = 10) or voriconazole (n = 9). Combination therapy was administered in 13 patients (56.5%). Susceptibility testing showed high minimum inhibitory concentrations for azoles and amphotericin B, but not for echinocandins. No preferable treatment influencing favourable outcome was identified. Overall mortality was 39% (n = 9).

CONCLUSION

Rasamsonia spp. are emerging fungi causing life-threatening infections, especially in immunocompromised and critically ill patients. Mortality is high. Treatment is challenging and clinicians dealing with this patient population should become aware of this infection constituting a medical emergency.

Management of Invasive Fungal Infections in Adult Patients with Hematological Malignancies in Greece during the Financial Crisis: Challenges and Recommendations

There are concerns that the financial crisis in Greece negatively affected the management of invasive fungal infections (IFIs) among patients with hematological malignancies (HM). A working group (WG) was formed to explore the situation and make recommendations. A questionnaire was created and distributed to physicians caring for patients with HM, to gather information in a standardized manner on prescribing physicians, patient characteristics, availability of diagnostics, antifungal treatment practices and the conditions and particularities of Greek hospitals. A total of 141 physicians from 36 hematology units and laboratories located in 26 Greek hospitals participated. Regarding hospitalization conditions, only 56% reported that their patients were treated in isolated single or double bed rooms, 22% reported availability of HEPA filters, 47% reported construction works in progress, and an alarming 18% reported the presence of birds on open windows. Regarding diagnosis, only 31% reported availability of biomarkers for diagnosis of IFIs, 76% reported that CT scans were performed in a timely fashion, 42% reported prompt availability of broncho-alveolar lavage, and only 6% availability of therapeutic drug monitoring. Of concern, 26% of the responders reported non-availability of some antifungals. In conclusion, significant challenges exist for the optimal management of IFIs in patients with HM in Greece.

Prolonged voriconazole treatment in a patient with chronic lymphocytic leukemia resulting in a litany of chronic overlapping toxicities

Voriconazole is a triazole antifungal with activity against a number of yeast and mold species including Candida, Aspergillosis, Fusarium, and Coccidioides. Invasive fungal infections are associated with high morbidity and mortality, prolonged treatment courses, and occasionally lifelong suppressive therapy. Voriconazole therapy can result in a number of acute toxicities that clinicians are frequently aware of including hepatotoxicity, visual disturbances, and hallucinations; however, there is limited experience with extended durations of voriconazole therapy. We describe the case of a 62-year-old man who developed Coccidioides meningitis as a result of prolonged neutropenia from treatment for chronic lymphocytic leukemia. He was initially treated with a number of different antifungal agents including voriconazole, liposomal amphotericin B, fluconazole, and itraconazole; however, he developed acute toxicity due to those agents. He was successfully re-challenged with voriconazole, and maintained therapeutic serum concentrations throughout treatment. As a result of prolonged voriconazole exposure of over 14 years, he has suffered a number of toxicities, most significantly including actinic keratosis, squamous cell carcinoma, and skeletal fluorosis. To our knowledge, this is the longest continuous use of voriconazole therapy currently in the literature.

Nucleic acid amplification methodologies for the detection of pulmonary mold infections

INTRODUCTION

The detection of pulmonary mold infections has historically required technically demanding methods obtained through invasive procedures. Nucleic acid amplification assays have the potential to circumvent the technical hurdles associated with diagnosis, but are not without potential pitfalls. Areas covered: In this paper, the authors review new assays for the diagnosis of pulmonary mold infections due to aspergillosis, mucormycosis, and hyalohyphomycoses as well as uncommon infections caused by dematiaceous molds. Expert commentary: Nucleic acid amplification assays have the potential to rapidly identify patients with invasive mycoses and could shorten the time to implementation of appropriate antimicrobial therapy. However, selection of appropriate patient populations will be crucial to ensure the highest Bayesian positive predictive value for any novel diagnostic platform.

Identification and Characterization of a Novel Aspergillus fumigatus Rhomboid Family Putative Protease, RbdA, Involved in Hypoxia Sensing and Virulence

Aspergillus fumigatus is the most common pathogenic mold infecting humans and a significant cause of morbidity and mortality in immunocompromised patients. In invasive pulmonary aspergillosis, A. fumigatus spores are inhaled into the lungs, undergoing germination and invasive hyphal growth. The fungus occludes and disrupts the blood vessels, leading to hypoxia and eventual tissue necrosis. The ability of this mold to adapt to hypoxia is regulated in part by the sterol regulatory element binding protein (SREBP) SrbA and the DscA to DscD Golgi E3 ligase complex critical for SREBP activation by proteolytic cleavage. Loss of the genes encoding these proteins results in avirulence. To identify novel regulators of hypoxia sensing, we screened the Neurospora crassa gene deletion library under hypoxia and identified a novel rhomboid family protease essential for hypoxic growth. Deletion of the A. fumigatus rhomboid homolog rbdA resulted in an inability to grow under hypoxia, hypersensitivity to CoCl2, nikkomycin Z, fluconazole, and ferrozine, abnormal swollen tip morphology, and transcriptional dysregulation-accurately phenocopying deletion of srbA. In vivo, rbdA deletion resulted in increased sensitivity to phagocytic killing, a reduced inflammatory Th1 and Th17 response, and strongly attenuated virulence. Phenotypic rescue of the ΔrbdA mutant was achieved by expression and nuclear localization of the N terminus of SrbA, including its HLH domain, further indicating that RbdA and SrbA act in the same signaling pathway. In summary, we have identified RbdA, a novel putative rhomboid family protease in A. fumigatus that mediates hypoxia adaptation and fungal virulence and that is likely linked to SrbA cleavage and activation.

Healthcare-associated outbreaks due to Mucorales and other uncommon fungi

BACKGROUND

Healthcare-associated outbreaks of fungal infections, especially with uncommon and emerging fungi, have become more frequent in the past decade.

MATERIALS AND METHOD

Here, we reviewed the history and definition of healthcare-associated outbreaks of uncommon fungal infections and discussed the principles of investigating, containing and treatment of these outbreaks.

RESULTS

In case of these uncommon diseases, occurrence of two or more cases in a short period is considered as an outbreak. Contaminated medical devices and hospital environment are the major sources of these outbreaks. Care must be taken to differentiate a real infection from colonization or contamination. Defining and identifying cases, describing epidemiologic feature of cases, finding and controlling the source of the outbreak, treating patients, and managing asymptomatic exposed patients are main steps for outbreak elimination. These fungal outbreaks are not only difficult to detect but also hard to treat. Early initiation of appropriate antifungal therapy is strongly associated with improved outcomes in infected patients. Choice of antifungal drugs should be made based on spectrum, pharmacodynamic and pharmacokinetic characteristics and adverse effects of available drugs. Combination antifungal therapy and surgical intervention may be also helpful in selected cases.

CONCLUSIONS

A multidisciplinary approach and close collaboration between all key partners are necessary for successful control of fungal outbreaks.