Performance of the beta-glucan test for the diagnosis of invasive fusariosis and scedosporiosis: a meta-analysis

The comparative genomic analysis provides insight into the divergent inhibitory activity metabolites in pathogen-driven three Pseudomonas palleroniana strains against primary pathogens of Pseudostellaria heterophylla

Pseudostellaria heterophylla (Miq.) Pax ex Pax et Hoffm. is a member of the Caryophyllaceae family, in which dried tuberous root is the well-known traditional Chinese medicine (TCM) and a widespread food ingredient in Asia. In recent years, the large-scale cultivation of P. heterophylla has led to frequent infectious diseases caused by multiple pathogens. However, efficient and safe approaches for preventing and managing P. heterophylla diseases have become urgent for this high-quality industrial development. Herein, a culturable microbiome of diseased P. heterophylla rhizosphere soil was constructed, and the broad-spectrum antifungal activity of Pseudomonas was screened. Three P. palleroniana strains, B-BH16-1, B-JK4-1, and HP-YBB-1B, were isolated and identified with vigorous antifungal activity by confrontation method. We employed the PacBio RS II single-molecule real-time (SMRT) sequencing and Illumina sequencing methods to obtain the genome of these three isolates. Phylogenetic, synteny, and ANI analysis showed that the lineage between strain B-JK4-1 with B-BH16-1 or HY-YBB-1B was closer than that between strain B-BH16-1 with HP-YBB-1B. The comparative genome of strains B-BH16-1, B-JK4-1, and HP-YBB-1B showed marked differences in secondary metabolite biosynthesis genes among these three P. palleroniana strains. Strain B-BH16-1, B-JK4-1, and HP-YBB-1 produced tolaasin I/tolaasin F (23 genes), sessilin A (37 genes), and putisolvin (39 genes), respectively. CAZyme analysis showed that 126, 129, and 127 CAZymes were identified in strains B-BH16-1, B-JK4-1, and HP-YBB-1B genomes, which genes in auxiliary activities (AA), carbohydrate esterases (CE), and glycosyl transferases (GT) categories were different among these three strains. These results provide new insights into the divergent antifungal metabolites in pathogen-driven three P. palleroniana strains against primary pathogens of Pseudostellaria heterophylla.

Invasive Fungal Infection by Scedosporium apiospermum with Cerebral Involvement in a Pediatric Patient Affected by Chronic Granulomatous Disease After Hematopoietic Cell Transplant

A 5-year-old boy affected by chronic granulomatous disease (CGD) underwent two allogeneic hematopoietic cell transplants (HCT) from the same unrelated donor. The first HCT was complicated by prolonged fever and primary graft failure. While fully aplastic, the patient developed a disseminated infection by Scedosporium apiospermum involving the knee and parasternal skin (day +34 and +40 post-HCT). The patient was treated with voriconazole and granulocyte transfusions followed by a second HCT 80 days after the first HCT. At day +105, the patient developed fever, headache, and altered level of consciousness associated with multiple bilateral cerebral abscesses at magnetic resonance imaging. The serum B-D-glucan test was positive. Micafungin was added to voriconazole. Despite an initial clinical improvement, the patient developed hydrocephalus. Scedosporium apiospermum was cultured from cerebrospinal fluid. Liposomal amphotericin B, instead of micafungin, was combined with voriconazole as salvage therapy. Unfortunately, the patient developed uncal herniation and died at day +193 from HCT. This case shows that the prognosis of scedosporiosis remains poor despite adequate antifungal treatment. Noteworthy, the B-D-Glucan test is confirmed useful as a non-invasive marker for early diagnosis and may help the differential diagnosis of mycoses.

American Society of Transplantation and Cellular Therapy Series: #8-Management and Prevention of Non-Aspergillus Molds in Hematopoietic Cell Transplantation Recipients

The Practice Guidelines Committee of the American Society of Transplantation and Cellular Therapy partnered with its Transplant Infectious Disease Special Interest Group to create a guideline focusing on non-Aspergillus invasive molds, which are uncommon yet lethal invasive fungal diseases in the peri-hematopoietic cell transplant (HCT) period. We used a compendium-style approach by dissecting this broad, heterogeneous, and highly complex topic into a series of standalone frequently asked questions (FAQs) and tables. Adult and pediatric infectious diseases and HCT content experts developed, then answered FAQs, and finalized topics with harmonized recommendations. All the evidence for non-Aspergillus invasive mold infection is non-RCT and mostly level III, therefore there are no recommendation grades, and instead key references are provided. Through this format, this "8th" topic in the series focuses on the relevant risk factors, diagnostic considerations, prophylaxis, and treatment approaches relevant to rare mold infections in the pre- and post-transplant periods.

Diagnosis and management of invasive fungal infections due to non-Aspergillus moulds

Invasive fungal infection (IFI) due to moulds other than Aspergillus are a significant cause of morbidity and mortality. Non-Aspergillus mould (NAM) infections appear to be on the increase due to an ever-expanding population of immunocompromised hosts. In this review, Mucorales, Scedosporium species, Lomentospora prolificans and Fusarium species are examined in detail, and the microbiology, risk factors, diagnosis and treatment of emerging NAMs such as Paecilomyces variotti, Purpureocillium lilacinum and Rasamsonia are summarized. The challenges in diagnosis are emphasized and the emerging importance of molecular methods is discussed. Treatment of IFI due to NAMs is a multi-pronged and multi-disciplinary approach. Surgery, correction of underlying risk factors, and augmentation of the host immune response are as important as antifungal therapy. Many of these NAMs are intrinsically resistant to the currently licensed antifungal agents, so selection of therapy needs to be guided by susceptibility testing. There are new antifungal agents in development, and these have the potential to improve the efficacy and safety of antifungal treatment in the future. Ongoing research is required to fully delineate the epidemiology of NAM infections, and to develop better diagnostic tools and treatments so that outcomes from these infections can continue to improve.

Progress on nonculture based diagnostic tests for invasive mould infection

PURPOSE OF REVIEW

This review describes the current status of diagnosing invasive mould disease and Pneumocystis pneumonia using nonconventional diagnostics methods.

RECENT FINDINGS

There has been significant development in the range of nonculture mycological tests. Lateral flow tests (LFTs) for diagnosing aspergillosis complement galactomannan ELISA testing, and LFTs for other fungal diseases are in development. Rapid and low through-put B-D-Glucan assays increase access to testing and there has been significant progress in the standardization/development of molecular tests. Despite this, no single perfect test exists and combining tests (e.g., antigen and molecular testing) is likely required for the optimal diagnosis of most fungal diseases.

SUMMARY

Based on established clinical performance few mycological tests can be used alone for optimal diagnosis of fungal disease (FD) and combining tests, including classical approaches is the preferred route for confirming and excluding disease. Next-generation sequencing will likely play an increasing role in how we diagnose disease, but optimization, standardization and validation of the entire molecular process is needed and we must consider how host biomarkers can stratify risk. Given the burden of FD in low- and medium-income countries, improved access to novel but more so existing diagnostic testing is critical along with simplification of testing processes.

Fusarium spp. causing invasive disease in humans: A case series from north India

Owing to their inherent resistance to different classes of antifungals, early identification of Fusarium spp. is crucial. In this study, 10 clinical isolates were included from patients with invasive fusariosis involving lungs, sinuses, or both. Clinico-radiological data were collected. Samples were processed by standard laboratory procedures. Three gene regions (ITS, TEF1, and RPB2) were amplified by PCR for multilocus sequencing. Fusarium MLST, FUSARIUM-ID, and FUSARIOID-ID databases were used for final identification. Antifungal susceptibility testing was performed by broth microdilution following CLSI M38-A3 and Sensititre™ YeastOne™ YO9 plate. Pulmonary involvement was seen in all patients, and sino-nasal involvement was present in six. Radiologically, consolidations and cavitations were present in eight and six cases, respectively. Halo sign was present in six; reverse halo sign was also found in three of them. Direct microscopy showed septate hyphae that were morphologically different from those found in aspergillosis. Results of the molecular identification were as follows: two Fusarium irregulare, one Fusarium pernambucanum, one Fusarium incarnatum, one Fusarium sp. FIESC 30, two Fusarium keratoplasticum, one Fusarium falciforme, one Fusarium pseudonygamai, and one Fusarium delphinoides. For both Fusarium solani (FSSC) and Fusarium incarnatum-equiseti (FIESC) species complexes, amphotericin B had the lowest minimum inhibitory concentrations (MICs). Importantly, for terbinafine, all FIESC isolates had low MICs, while FSSC isolates had high MICs. In some cases, early identification of Fusarium spp. is possible by means of morphology of hyphae on direct microscopy and findings on radiology. Molecular identification, at least to the species complex level, is crucial for the choice of antifungals.

Dynamic changes in serum (1-3)-β-D-glucan caused by intravenous immunoglobulin infusion: A prospective study

PURPOSE

The purpose of this study was to investigate the dynamic changes in serum (1-3)-β-D-glucan (BDG) caused by intravenous immunoglobulins (IVIG) infusion in adults.

METHODS

This study included patients who received IVIG infusion from October 2021 to October 2022 during hospitalization. We randomly examined two IVIG samples for every patient. Serum samples were collected at nine time points: before (Tpre), immediately (T1-0), 6h (T1-1) and 12h (T1-2) later on the first day; immediately (T2-0) and six hours later (T2-1) on the second day during IVIG infusion, and within three days after IVIG infusion (Ta1, Ta2, and Ta3, respectively). The Friedman test was used for statistical analysis.

RESULTS

A total of 159 serum BDG from 19 patients were included in the analysis. The BDG content of IVIG ranged from 249 pg/ml to 4812 pg/ml. Patients had significantly elevated serum BDG on T1-0 (176 (113, 291) pg/ml, p = 0.002) and Ta1 (310 (199, 470) pg/ml, p < 0.001), compared with Tpre (41 (38, 65) pg/ml). The increments of serum BDG (ΔBDG) were associated with BDG concentration of IVIG (Spearman r = 0.59, p = 0.02). Individuals with abnormal renal function indexes showed higher serum ΔBDG values at Ta1 (403 (207, 484) pg/ml) than patients with normal renal function (172 (85, 316) pg/ml, p = 0.036).

CONCLUSION

Patients who received IVIG had significantly higher serum BDG values. Elevated BDG levels correlate with BDG content of IVIG and abnormal renal function indexes.

Scedosporiosis and lomentosporiosis: modern perspectives on these difficult-to-treat rare mold infections

SUMMARYAlthough Scedosporium species and Lomentospora prolificans are uncommon causes of invasive fungal diseases (IFDs), these infections are associated with high mortality and are costly to treat with a limited armamentarium of antifungal drugs. In light of recent advances, including in the area of new antifungals, the present review provides a timely and updated overview of these IFDs, with a focus on the taxonomy, clinical epidemiology, pathogenesis and host immune response, disease manifestations, diagnosis, antifungal susceptibility, and treatment. An expansion of hosts at risk for these difficult-to-treat infections has emerged over the last two decades given the increased use of, and broader population treated with, immunomodulatory and targeted molecular agents as well as wider adoption of antifungal prophylaxis. Clinical presentations differ not only between genera but also across the different Scedosporium species. L. prolificans is intrinsically resistant to most currently available antifungal agents, and the prognosis of immunocompromised patients with lomentosporiosis is poor. Development of, and improved access to, diagnostic modalities for early detection of these rare mold infections is paramount for timely targeted antifungal therapy and surgery if indicated. New antifungal agents (e.g., olorofim, fosmanogepix) with novel mechanisms of action and less cross-resistance to existing classes, availability of formulations for oral administration, and fewer drug-drug interactions are now in late-stage clinical trials, and soon, could extend options to treat scedosporiosis/lomentosporiosis. Much work remains to increase our understanding of these infections, especially in the pediatric setting. Knowledge gaps for future research are highlighted in the review.

Fusarium species central nervous system infection

PURPOSE OF REVIEW

Fusarium species are an increasingly important cause of meningitis and invasive disease in immunocompromised patients as well as in otherwise healthy patients as observed in two recent healthcare-associated outbreaks. This review summarizes recently published information on treatment and diagnosis of this infection.

RECENT FINDINGS

Incidence of Fusarium species meningitis and invasive fusariosis are increasing. Molecular techniques are improving the speed of diagnosis. New antifungal agents in development show good in vitro activity against some Fusarium species. New technologies, including cerebrospinal fluid (CSF) filtration, may play a role in treatment of central nervous system (CNS) disease. Due to the continued prime importance of the host immune system in recovery, immunomodulatory treatments may play a role in treatment.

SUMMARY

The overall incidence of CNS fusariosis is increasing with a continued poor prognosis, but new diagnostic and treatment modalities are in development which may offer improvements.

PCR diagnostic platforms for non-Aspergillus mold infections: ready for routine implementation in the clinic?

INTRODUCTION

While Aspergillus spp. remain the predominant cause of invasive mold infections, non-Aspergillus molds, such as the Mucorales or Fusarium spp., account for an increasing proportion of cases. The diagnosis of non-Aspergillus invasive mold infections (NAIMI) is challenging because of the low sensitivity and delay of conventional microbiological tests. Therefore, there is a particular interest to develop molecular tools for their early detection in blood or other clinical samples.

AREAS COVERED

This extensive review of the literature discusses the performance of Mucorales-specific PCR and other genus-specific or broad-range fungal PCR that can be used for the diagnosis of NAIMI in diverse clinical samples, with a focus on novel technologies.

EXPERT OPINION

PCR currently represents the most promising approach, combining good sensitivity/specificity and ability to detect NAIMI in clinical samples before diagnosis by conventional cultures and histopathology. Several PCR assays have been designed for the detection of Mucorales in particular, but also Fusarium spp. or Scedosporium/Lomentospora spp. Some commercial Mucorales PCRs are now available. While efforts are still needed for standardized protocols and the development of more rapid and simpler techniques, PCR is on the way to becoming an essential test for the early diagnosis of mucormycosis and possibly other NAIMIs.

Epidural anesthesia causes outbreak of mycotic aneurysms: complications of Fusarium solani meningitis

BACKGROUND

A health advisory was issued in response to a fungal meningitis outbreak linked to epidural anesthesia exposure in two plastic surgery clinics in Mexico, from January 1 to May 13, 2023. This descriptive analysis describes the neuroendovascular and neurosurgical observations and management of patients treated at a single stroke center located along the US-Mexico Border.

METHODS

We conducted a retrospective chart review of fungal meningitis patients presenting between April and July 2023.

RESULTS

Among the patients diagnosed with fungal meningitis (n=12), the majority (n=11) were afflicted with angio-invasive Fusarium solani. 83% received dual antifungal therapy, with 40% initiated on alternate-day intrathecal amphotericin B. Diagnostic cerebral angiography was performed on all patients, revealing aneurysms in 58% of cases, predominantly within the posterior circulation, notably the basilar artery, with a median size of 4.2 mm (IQR 3.3-4.8). Treatment strategies included flow diversion (70%) and primary coiling (14%) for aneurysms. Ventriculostomy placement was undertaken in 67% of patients, with 37.5% of these requiring conversion to ventriculoperitoneal shunts. Subarachnoid hemorrhage development was uniformly associated with 100% mortality.

CONCLUSIONS

In patients presenting with Fusarium solani meningitis, weekly angiographic surveillance proved instrumental for monitoring aneurysm and vasospasm development. Conventional angiography outperformed CT angiography due to its enhanced ability to detect small aneurysms. A proactive approach to aneurysm treatment is advocated, given their elevated rupture risk. While our findings suggest the potential reversibility of angiographic vasospasm with effective antifungal treatment, we acknowledge the challenge of drawing definitive conclusions based on a limited sample size.

Approach to diagnostic evaluation and prevention of invasive fungal disease in patients prior to allogeneic hematopoietic stem cell transplant

In recent years, advancements in the treatment landscape for hematological malignancies, such as acute myeloid leukemia and acute lymphoblastic leukemia, have significantly improved disease prognosis and overall survival. However, the treatment landscape is changing and the emergence of targeted oral therapies and immune-based treatments has brought forth new challenges in evaluating and preventing invasive fungal diseases (IFDs). IFD disproportionately affects immunocompromised hosts, particularly those undergoing therapy for acute leukemia and allogeneic hematopoietic stem cell transplant. This review aims to provide a comprehensive overview of the pretransplant workup, identification, and prevention of IFD in patients with hematological malignancy. The pretransplant period offers a critical window to assess each patient's risk factors and implement appropriate prophylactic measures. Risk assessment includes evaluation of disease, host, prior treatments, and environmental factors, allowing a dynamic evaluation that considers disease progression and treatment course. Diagnostic screening, involving various biomarkers and radiological modalities, plays a crucial role in early detection of IFD. Antifungal prophylaxis choice is based on available evidence as well as individual risk assessment, potential for drug-drug interactions, toxicity, and patient adherence. Therapeutic drug monitoring ensures effective antifungal stewardship and optimal treatment. Patient education and counselling are vital in minimizing environmental exposures to fungal pathogens and promoting medication adherence. A well-structured and individualized approach, encompassing risk assessment, prophylaxis, surveillance, and patient education, is essential for effectively preventing IFD in hematological malignancies, ultimately leading to improved patient outcomes and overall survival.