Invasive mold infections of the central nervous system in patients with hematologic cancer or stem cell transplantation (2000–2016): Uncommon, with improved survival but still deadly often

Cerebrospinal fluid galactomannan detection for the diagnosis of central nervous system aspergillosis: a diagnostic test accuracy systematic review and meta-analysis

BACKGROUND

Cerebrospinal fluid (CSF) galactomannan is an adjunctive test for central nervous system (CNS) aspergillosis diagnosis with unclear diagnostic test characteristics.

OBJECTIVES

To evaluate the diagnostic test characteristics of CSF galactomannan in CNS aspergillosis.

METHODS

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, Web of Science, and Scopus, from inception to 24 February 2023.

STUDY ELIGIBILITY CRITERIA

Prospective and retrospective studies with 1-group and 2-group designs using any galactomannan assay on CSF to diagnose CNS aspergillosis.

PARTICIPANTS

Adult and/or paediatric patients with CNS aspergillosis.

TEST(S)

Galactomannan testing on CSF specimens.

REFERENCE STANDARD

European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium (EORTC/MSGERC) diagnostic criteria, or equivalent.

ASSESSMENT OF RISK OF BIAS

QUADAS-2 assessment in duplicate.

METHODS OF DATA SYNTHESIS

Bivariate restricted maximum likelihood estimation random-effects meta-analysis, summarized using forest and summary receiver operating characteristic plots; bivariate meta-regression models to investigate heterogeneity; and subgroup and sensitivity analyses to explore subgroup effects and methodologic choices (PROSPERO registration: CRD42022296331; funding: none).

RESULTS

We included eight studies (n = 342 participants). The summary estimates of CSF galactomannan sensitivity and specificity were 69.0% (95% CI, 57.2-78.7%) and 94.4% (95% CI, 82.8-98.3%), respectively. Using meta-regression, galactomannan cut-off (p = 0.38), EORTC/MSGERC criteria version (p = 0.48), or whether the reference standard was defined as both proven and probable or only proven aspergillosis (p = 0.48) did not explain observed heterogeneity. No subgroup effects were demonstrated by analysing the EORTC/MSGERC criteria reference standard used (e.g. 2002 vs. 2008 definitions) or whether paediatric patients were included. Diagnostic sensitivity was improved using a galactomannan cut-off of 1.0, and by excluding high risk of bias and 1-group design studies.

DISCUSSION

CSF galactomannan is a highly specific but insensitive test for use as a component of CNS aspergillosis diagnosis. Few included studies, no prospective studies, and a high risk of bias are study limitations.

Cerebral Infectious Opportunistic Lesions in a Patient with Acute Myeloid Leukaemia: The Challenge of Diagnosis and Clinical Management

Central nervous system (CNS) lesions, especially invasive fungal diseases (IFDs), in immunocompromised patients pose a great challenge in diagnosis and treatment. We report the case of a 48-year-old man with acute myeloid leukaemia and probable pulmonary aspergillosis, who developed hyposthenia of the left upper limb, after achieving leukaemia remission and while on voriconazole. Magnetic resonance imaging (MRI) showed oedematous CNS lesions with a haemorrhagic component in the right hemisphere with lepto-meningitis. After 2 weeks of antibiotics and amphotericin-B, brain biopsy revealed chronic inflammation with abscess and necrosis, while cultures were negative. Clinical recovery was attained, he was discharged on isavuconazole and allogeneic transplant was postponed, introducing azacitidine as a maintenance therapy. After initial improvement, MRI worsened; brain biopsy was repeated, showing similar histology; and 16S metagenomics sequencing analysis was positive (Veilonella, Pseudomonas). Despite 1 month of meropenem, MRI did not improve. The computer tomography and PET scan excluded extra-cranial infectious-inflammatory sites, and auto-immune genesis (sarcoidosis, histiocytosis, CNS vasculitis) was deemed unlikely due to the histological findings and unilateral lesions. We hypothesised possible IFD with peri-lesion inflammation and methyl-prednisolone was successfully introduced. Steroid tapering is ongoing and isavuconazole discontinuation is planned with close follow-up. In conclusion, the management of CNS complications in immunocompromised patients needs an interdisciplinary approach.

Rhizopus arrhizus infection in mice causes brain histopathological alterations and exacerbates neuronal apoptosis

Rhizopus arrhizus is a fungus that can cause central nervous system infections in animals, resulting in high morbidity and mortality, but the mechanism of injury is rarely reported. In this study, we investigated the mechanism of Rhizopus arrhizus damage to the central nervous system of mice by observing the clinical neurological symptoms and resolving the pathological changes in the ultrastructure of brain tissues, combined with the alteration of apoptosis-related genes and immunohistochemistry (IHC). The results showed that all the mice in the treated group died, the brain pyknosis of neurons, there were black mycelium aggregates around the blood vessels, and apoptotic vesicles were produced. The RT-qPCR results showed that, compared with the control group, the relative transcriptome levels of Caspase 8 and BcL-2 genes were significantly increased (P < 0.05), the relative transcriptome level of Caspase 9 gene was highly significant (P < 0.01), the relative transcriptome level of Caspase 3 and Bax gene was significantly decreased (P < 0.05), and the ratio of Bcl-2/Bax was significantly increased (P < 0.05) in the brains of the treated group. TUNEL staining showed that the rate of neuronal apoptosis in the treated group of mice was extremely significantly higher than that in the control group (P < 0.01). This study shows that Rhizopus arrhizus strain XMLO1 causes brain damage by triggering neuronal apoptosis. This study provided a theoretical basis for revealing the mechanism of Rhizopus arrhizus infection.

Invasive pulmonary and central nervous system aspergillosis in a child: A case report and literature review

RATIONALE

Children with haematological malignancies have a higher risk of developing aggressive pulmonary aspergillosis and a higher mortality rate. The most common site of extrapulmonary aspergillosis in children is the central nervous system (CNS), and the death rate is higher when CNS is affected. Therefore, early diagnosis and treatment of invasive aspergillosis are essential for reducing mortality.

PATIENT CONCERNS

We report a case of an 8-year-old girl with acute lymphoblastic leukaemia who developed invasive pulmonary aspergillosis complicated by CNS aspergillosis. Aspergillus was confirmed by metagenomic sequencing of pathogenic microorganisms.

DIAGNOSES

Invasive pulmonary and central nervous system aspergillosis.

INTERVENTIONS

The patient was treated with combined systemic antifungal agents (voriconazole and liposomal amphotericin B) and intrathecal injection of amphotericin B.

OUTCOMES

The treatment was well tolerated and resulted in remarkable clinical and radiological head improvements.

LESSONS

Invasive aspergillosis has a high mortality rate and requires early diagnosis and treatment. Pathogenic microbial metagenomic sequencing is a convenient method to assist in the early diagnosis of aspergillosis. Voriconazole is the drug of choice for the treatment of invasive aspergillosis. When CNS aspergillosis occurs, it can be combined with other systemic antifungal drugs and intrathecal injection of amphotericin B.

Development of a murine model to study the cerebral pathogenesis of Aspergillus fumigatus

IMPORTANCE

Molds are environmental fungi that can cause disease in immunocompromised individuals. The most common pathogenic mold is Aspergillus fumigatus, which is typically inhaled into the lungs and causes invasive pulmonary disease. In a subset of these patients, this infection can spread from the lungs to other organs including the brain, resulting in cerebral aspergillosis. How A. fumigatus causes brain disease is not well understood and these infections are associated with extremely high mortality rates. Thus, we developed an animal model to study the pathogenesis of cerebral aspergillosis to better understand this disease and develop better treatments for these life-threatening infections.

Evolution of neuroimaging findings in angioinvasive cerebral aspergillosis in a pediatric patient with leukemia during long-term observation

The central nervous system is one of the most common sites of aspergillosis involvement in immunocompromised people, just after sinopulmonary infections. Neuroimaging modalities are crucial for the diagnosis of cerebral aspergillosis (CA). Here, we describe a rare case of concurrent mixed aspergillosis infection with Aspergillus fumigatus and Aspergillus niger in a 2-year-old leukemic boy. The first neuroimaging finding, which was followed by focal seizures, was recognized as extensive cerebral hemorrhage in the absence of thrombocytopenia and coagulopathy. As the patient survived for more than 4 months after diagnosis, we were able to perform a neuroimaging evaluation during long-term observation. In serial neuroimaging studies, a secondary fungal abscess was observed at the site of hemorrhagic infarctions. Finally, the patient died from bacterial sepsis. In this case study, we try to categorize the neuroimaging findings of CA into distinct phases to better understand how CA changes over time.

COVID-19-Associated Rhino-Orbital Mucormycosis in a Tertiary Health Care Center in Odisha, India

Background Mucormycosis is an opportunistic infection that mainly affects immunocompromised individuals, including those with uncontrolled diabetes, malignancies, or those who have exposure to high-dose corticosteroids for a long time. Western Odisha, India, witnessed a significant rise in post-COVID-19 rhino-orbital mucormycosis (ROM), which created a need for comprehensive research on post-COVID-19 ROM. Objective This study aimed to investigate the prevalence, clinical characteristics, and outcomes of post-COVID-19 ROM in a tertiary care hospital in Western Odisha, India, with the objective of understanding ROM as a nationally notifiable disease. Subjects and methods A prospective hospital-based study was conducted. Mucormycosis cases were reported within the period, from May 17, 2021, to July 31, 2021, including all post-COVID-19 patients who exhibited clinical manifestations of mucormycosis. Patients with histopathologically negative reports of mucormycosis were excluded. Results Of the 35 included, 25 were diagnosed with ROM. The age group of 46-50 years showed a predominance (n=6), with a mean age of 50.53 years. The male-to-female ratio was 2:1. Specifically, 88% of the patients included had diabetes mellitus, 8% had chronic kidney diseases, 8% had sepsis, and 4% had hypertension. ROM was the predominant manifestation (60%, n=15), with the majority presenting with orbital cellulitis (80%), followed by unilateral orbital apex syndrome (12%), bilateral orbital apex syndrome (4%), ophthalmic vein involvement (4%), and osteomyelitis of the maxillary sinus (4%). Irrigation of the wound was performed, and all 25 ROM patients received IV liposomal amphotericin B (L-AMB). Conclusion Post-COVID-19 status with elevated blood sugar levels was a major risk factor for ROM. Early diagnosis, debridement, L-AMB, retrobulbar AMB deoxycholate, and exenteration are the possible solutions.

Central Nervous System Fungal Infections in Children With Leukemia and Undergoing Hematopoietic Stem Cell Transplantation: A Retrospective Multicenter Study

BACKGROUND

Central nervous system fungal infections (CNSFI) are seen in patients with hematologic malignancies and have high morbidity and mortality. Because of their rarity, there is limited data on CNSFI in children with no established treatment protocols or guidelines.

MATERIALS AND METHODS

In this multicenter retrospective study, 51 pediatric patients with leukemia, 6 of whom had undergone bone marrow transplantation, with proven or probable CNSFI were evaluated. Fungal infections were defined as proven or probable based on European Organisation for Research and Treatment of Cancer criteria. Proven CNSFI was diagnosed by appropriate central nervous system (CNS) imaging or tissue sample findings in combination with positive microbiological results of cerebrospinal fluid. A positive culture, microscopic evidence of hyphae, a positive result of the galactomannan assays are defined as positive microbiological evidence. Probable CNSFI was defined as appropriate CNS imaging findings together with proven or probable invasive fungal infections at another focus without CNS when there is no other explanatory condition. Data was collected by using the questionnaire form (Supplemental Digital Content 1, http://links.lww.com/JPHO/A541 ).

RESULTS

Seventeen patients had proven, 34 patients had probable CNSFI. Headaches and seizures were the most common clinical findings. The median time between the onset of fever and diagnosis was 5 days. The most common fungal agent identified was Aspergillus . Sixteen patients received single-agent, 35 received combination antifungal therapy. Surgery was performed in 23 patients. Twenty-two patients (43%) died, 29 of the CNSFI episodes recovered with a 20% neurological sequelae.

CONCLUSION

CNSFIs should be considered in the differential diagnosis in patients with leukemia and refractory/recurrent fever, headache, neurologicalocular symptoms, and a radiologic-serological evaluation should be performed immediately. Early diagnosis and prompt management, both medical and surgical, are essential for improving clinical outcomes.

A Systematic Review to Assess the Relationship between Disseminated Cerebral Aspergillosis, Leukemias and Lymphomas, and Their Respective Therapeutics

Disseminated disease following invasive pulmonary aspergillosis (IPA) remains a significant contributor to mortality amongst patients with hematologic malignancies (HMs). At the highest risk of mortality are those with disseminated disease to the central nervous system, known as cerebral aspergillosis (CA). However, little is known about the risk factors contributing to disease amongst HM patients. A systematic review using PRISMA guidelines was undertaken to define HM patient subgroups, preventative measures, therapeutic interventions, and outcomes of patients with disseminated CA following IPA. The review resulted in the identification of 761 records, of which 596 articles were screened, with the final inclusion of 47 studies and 76 total patients. From included articles, the proportion of CA was assessed amongst HM patient subgroups. Further, pre-and post-infection characteristics, fungal species, and mortality were evaluated for the total population included and HM patient subgroups. Patients with acute myeloid leukemia and acute lymphoid lymphoma, patients receiving corticosteroids as a part of their HM therapeutic regimen, and anti-fungal prophylaxis constitute the top identified patient populations at risk for disseminated CA. Overall, information presented here indicates that measures for the prevention of IPA should be taken in higher-risk HM patient subgroups. Specifically, the type of anti-fungal therapy used should be carefully considered for those patients with IPA and increased risk for cerebral dissemination. Additional reports detailing patient characteristics are needed to define further the risk of developing disseminated CA from IPA in patients with HMs.

Antibody responses and CNS pathophysiology of Mucormycosis in Chronic SARS CoV-2 infection: Current Therapies against Mucormycosis

The incidence rate of opportunistic secondary infections through invasive fungi has been observed to be 14.5% to 27% in the SARS CoV pandemic during the year 2003. But, the incidence of SARS CoV-2 is accompanied by the substantial rise in secondary opportunistic infections like mucormycosis (black fungus) mainly in the immunocompromised individuals, and diabetic patients taking steroids. Substantial rates of COVID-19 cases with mucormycosis were reported in India and other parts of the world. Previous research reports delineated the ability of Mucorales in invading the various tissues like lungs, brain, sinus through the GRP78 and subsequently this infection could invoke crusting, edema, and necrosis of brain parenchyma, ptosis, proptosis, and vision loss due to intraorbital & intracranial complications. Similarities of these pathophysiological complications with already existing diseases are causing clinicians to face several challenges in order to diagnose and treat this disease effectively at the early stage. This minireview depicts the mucormycosis-induced immune, and pathophysiological alterations in COVID-19 patients comorbid with diabetes, immunosuppression, and also reported the various clinical manifestations, and the therapeutic modalities and the failures of anti-fungal vaccines. Therefore, the emerging mucormycosis in COVID-19 patients need a rapid investigation and selective optimization of the effective therapeutic modalities including antifungal vaccines to minimize mortality rate.

Mucormycosis: An opportunistic pathogen during COVID-19

The pandemic of coronavirus disease 2019 (COVID-19) still remains on an upsurge trend. The second wave of this disease has led to panic in many countries, including India and some parts of the world suffering from the third wave. As there are no proper treatment options or remedies available for this deadly infection, supportive care equipment's such as oxygen cylinders, ventilators and heavy use of steroids play a vital role in the management of COVID-19. In the midst of this pandemic, the COVID-19 patients are acquiring secondary infections such as mucormycosis also known as black fungus disease. Mucormycosis is a serious, but rare opportunistic fungal infection that spreads rapidly, and hence prompt diagnosis and treatment are necessary to avoid high rate of mortality and morbidity rates. Mucormycosis is caused by the inhalation of its filamentous (hyphal form) fungi especially in the patients who are immunosuppressed. Recent studies have documented alarming number of COVID-19 patients with mucormycosis infection. Most of these patients had diabetes and were administered steroids for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and were consequently more prone to mucormycosis. Hence, the present review emphasizes mucormycosis and its related conditions, its mechanism in normal and COVID-19 affected individuals, influencing factors and challenges to overcome this black mold infection. Early identification and further investigation of this fungus will significantly reduce the severity of the disease and mortality rate in COVID-19 affected patients.

Current Pharmaceutical Aspects of Synthetic Quinoline Derivatives

Quinoline derivatives are considered broad-spectrum pharmacological compounds that exhibit a wide range of biological activities. Integration of quinoline moiety can improve its physical and chemical properties and also pharmacological behavior. Due to its wide range of pharmaceutical applications, it is a very popular compound to design new drugs for the treatment of multiple diseases like cancer, dengue fever, malaria, tuberculosis, fungal infections, AIDS, Alzheimer's disease and diabetes. In this review, our major focus is to pay attention to the biological activities of quinoline compounds in the treatment of these diseases such as anti-viral, anti-cancer, anti-malarial, antibacterial, anti-fungal, anti-tubercular and anti-diabetic.

Occam or Hickham? The diagnostic dilemma of an inflammatory brain lesion in the setting of pulmonary aspergillosis and previous neurosurgery

INTRODUCTION

Occam's Razor is a precept which invites one to consider the simplest and most unifying diagnosis as correct. In the modern era, clinical diagnosis remains critical in selecting appropriate therapies yet grows ever more complex with increased information from diagnostic technologies, but not always with sufficient granularity to answer the clinical question with certainty. We present an example of this dilemma in a patient with complex partial seizures on a background of pulmonary aspergillosis and historic clipping of a middle cerebral artery (MCA) aneurysm.

CASE DESCRIPTION

A 69-year-old female presented with progressive headaches, temporal lobe seizures, poor short-term memory and weight loss. She had suffered a subarachnoid haemorrhage 22 years earlier requiring surgical repair of a right MCA aneurysm. She was treated for breast cancer in 2006 followed by pulmonary aspergilloma in 2014 for which systemic antifungals were discontinued due to toxicity. Imaging revealed a right temporal inflammatory lesion adjacent to the aneurysm clip. Gastrointestinal toxicity and haemoptysis complicated the clinical and radiological response to systemic steroids. Cerebral aspergillosis was considered given her medical history despite an equivocal fungal screen, but intolerable side effects negated the continued use of systemic antifungals. Surgical exploration to establish a definitive diagnosis and potentially treat the underlying cause was recommended despite the high surgical risk involved and subsequently revealed a foreign body type granuloma, and excluded aspergillosis. Tuberculosis and other granulomatous disease processes were excluded.

CONCLUSION

This case illustrates the importance of pathological diagnosis to guide therapy and reminds us that the occasional patient will encounter multiple, rare and unrelated diseases during their lifetime. A high index of suspicion is necessary in patients who have undergone surgical aneurysm repair involving muslin as it may be subject to secondary infection and or granuloma formation many years later.

Aspergillosis of central nervous system in patients with leukemia and stem cell transplantation: a systematic review of case reports

Background

Aspergillosis of Central Nervous System (CNS) is a highly lethal infection in patients with leukemia and Stem Cell Transplantation (SCT).

Methods

Case reports of CNS aspergillosis in patients with leukemia and SCT published between 1990 and August 2020 were gathered using a structured search through PubMed/Medline.

Results

Sixty-seven cases were identified over the searches of the PubMed bibliographic database and then, 59 cases were included in the final analysis. Europe had the largest share of cases at 57.6% (34 reports), followed by Americas and Asia. Affected patients were predominantly males (58.6%) and the mean age of the patients was 36.1 years, while 62.7% of the patients were under the age of 50 years. The most common leukemia types include Acute Lymphoblastic Leukemia (ALL), Chronic Lymphocytic Leukemia (CLL), and Acute Myeloid Leukemia (AML) at 43.4%, 27.4%, and 23.5%, respectively. Furthermore, stem cell transplantation was reported in 11 cases. The overall mortality was 33%; however, the attributable mortality rate of CNS aspergillosis was 24.5%. Altered mental status, hemiparesis, cranial nerve palsies, and seizures were the clearest manifestations of infection and lung involvement reported in 57% of the patients. Histopathologic examination led to the diagnosis of infection in 57% of the patients followed by culture (23.7%), galactomannan assay (8.5%), and molecular method (3.3%). Amphotericin B and voriconazole were the most frequently used drugs for infection treatment. Good results were not obtained in one-third of the patients treated by voriconazole. Finally, neurosurgical intervention was used for 23 patients (39%).

Conclusion

CNS aspergillosis is a rapidly progressive infection in leukemic patients. Thus, these patients should be followed up more carefully. Furthermore, management of induction chemotherapy, use of different diagnostic methods, and use of appropriate antifungal can lead to infection control.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-021-00452-9.

A closer look at pathogenesis of cerebral mucormycosis in diabetic condition: A mini review

Patients with diabetes are considered a high-risk group involved with cerebral mucormycosis (CM). Due to the potential of Mucorales to invade sinuses and its rapid progression into orbit and retro-orbital areas and even brain, in most cases, CM is fatal in patients with diabetes. In the last few decades, mucormycosis and background conditions responsible for the development of its infections have received a great deal of attention. Dysfunction of innate and adaptive immune system, the increased amount of available nutrition, expression of host factors, and free iron level in plasma in diabetic ketoacidosis are among the topics that have been mostly taken into account so far. Therefore, it is important to clarify the molecular mechanisms that let the Mucorales to involve the patients with diabetes, which even at early stages of diagnosis and treatment, there is minimum chance to control the disease.

Cerebral and pulmonary aspergillosis, treatment and diagnostic challenges of mixed breakthrough invasive fungal infections: case report study

Background

Breakthrough invasive fungal infections (bIFIs) are an area of concern in the scarcity of new antifungals. The mixed form of bIFIs is a rare phenomenon but could be potentially a troublesome challenge when caused by azole-resistant strains or non-Aspergillus fumigatus. To raise awareness and emphasize diagnostic challenges, we present a case of mixed bIFIs in a child with acute lymphoblastic leukemia.

Case presentation

A newly diagnosed 18-month-old boy with acute lymphoblastic leukemia was complicated with prolonged severe neutropenia after induction chemotherapy. He experienced repeated episodes of fever due to extended-spectrum beta-lactamase-producing Escherichia coli bloodstream infection and pulmonary invasive fungal infection with Aspergillus fumigatus (early-type bIFIs) while receiving antifungal prophylaxis. Shortly after pulmonary involvement, his condition aggravated by abnormal focal movement, loss of consciousness and seizure. Cerebral aspergillosis with Aspergillus niger diagnosed after brain tissue biopsy. The patient finally died despite 108-day antifungal therapy.

Conclusions

Mixed bIFIs is a rare condition with high morbidity and mortality in the patients receiving immunosuppressants for hematological malignancies. This case highlights the clinical importance of Aspergillus identification at the species level in invasive fungal infections with multiple site involvement in the patients on antifungal prophylaxis.

Central Nervous System Infections Due to Aspergillus and Other Hyaline Molds

Central nervous system infections due to Aspergillus spp and other hyaline molds such as Fusarium and Scedosporium spp are rare but fatal conditions. Invasion of the central nervous system (CNS) tends to occur as a result of hematogenous dissemination among immunocompromised patients, and by local extension or direct inoculation secondary to trauma in immunocompetent hosts. Efforts should be directed to confirm the diagnosis by image-guided stereotactic brain biopsy when feasible. Non-culture methods could be useful to support the diagnosis, but they have not been validated to be performed in cerebral spinal fluid. Treatment of these infections is challenging given the variable susceptibility profile of these pathogens and the penetration of antifungal agents into the brain.

Broad-spectrum antifungal activity of spirooxindolo-pyrrolidine tethered indole/imidazole hybrid heterocycles against fungal pathogens

Invasive fungal infections are one of the leading causes of nosocomial bloodstream infections with a limited treatment option. A series of derivatized spirooxindolo-pyrrolidine tethered indole and imidazole heterocyclic hybrids have been synthesized, and their antifungal activity against fungal strains were determined. Here we characterize the antifungal activity of a specific spirooxindolo-pyrrolidine hybrid, dubbed compound 9c, a spirooxindolo-pyrrolidine tethered imidazole synthesized with a 2-chloro and trifluoromethoxy substituent. The compound 9c exhibited no cytotoxicity against mammalian cell line at concentrations that inhibited fungal strains. Compound 9c also significantly inhibited the fungal hyphae and biofilm formation. Our results indicate that spirooxindolo-pyrrolidine heterocyclic hybrids potentially represent a broad class of chemical agents with promising antifungal potential.

Mucormycosis of the Central Nervous System

Mucormycosis involves the central nervous system by direct extension from infected paranasal sinuses or hematogenous dissemination from the lungs. Incidence rates of this rare disease seem to be rising, with a shift from the rhino-orbital-cerebral syndrome typical of patients with diabetes mellitus and ketoacidosis, to disseminated disease in patients with hematological malignancies. We present our current understanding of the pathobiology, clinical features, and diagnostic and treatment strategies of cerebral mucormycosis. Despite advances in imaging and the availability of novel drugs, cerebral mucormycosis continues to be associated with high rates of death and disability. Emerging molecular diagnostics, advances in experimental systems and the establishment of large patient registries are key components of ongoing efforts to provide a timely diagnosis and effective treatment to patients with cerebral mucormycosis.

In vitro activity of voriconazole and amphotericin B against Candida albicans, Candida krusei, and Cryptococcus neoformans in human cerebrospinal fluid

PURPOSE

Fungal central nervous system (CNS) infections show a high mortality rate and only a few antifungal agents are available to treat these infections. We hypothesize that the different biochemical properties of human cerebrospinal fluid (CSF) compared to the standard growth medium lead to the altered activity of antifungal agents in CSF. We investigated the in vitro activity of two of these agents, i.e., amphotericin B (AmB) and voriconazole (VOR), against three different fungi in CSF in comparison to sabouraud-dextrose broth (SDB).

METHODS

CSF samples from patients who did not receive any antibiotics were collected. Time-kill curves were performed in CSF and SDB using static antibiotic concentrations of AmB and VOR against ATCC strains of Candida albicans, Candida krusei, and Cryptococcus neoformans.

RESULTS

In our experiments, both AmB and VOR showed superior activity in SDB compared to CSF. Nevertheless, AmB achieved fungicidal activity in CSF after 24 h against all test strains. Voriconazole only achieved fungistatic activity against C. albicans and C. neoformans in CSF.

CONCLUSIONS

In summary, our data demonstrate that growth of fungal pathogens but even more importantly activity of antifungal agents against Candida and Cryptococcus species can differ significantly in CSF compared to the standard growth medium. Both findings should be taken into consideration when applying PK/PD simulations to fungal infections of the CNS.

Fungal infections of the central nervous system and paranasal sinuses in onco-haematologic patients. Epidemiological study reporting the diagnostic-therapeutic approach and outcome in 89 cases

Invasive fungal infections (IFI) of the Central Nervous System (IFI-CNS) and Paranasal Sinuses (IFI-PS) are rare, life-threatening infections in haematologic patients, and their management remains a challenge despite the availability of new diagnostic techniques and novel antifungal agents. In addition, analyses of large cohorts of patients focusing on these rare IFI are still lacking. Between January 2010 and December 2016, 89 consecutive cases of Proven (53) or Probable (36) IFI-CNS (71/89) and IFI-PS (18/89) were collected in 34 haematological centres. The median age was 40 years (range 5-79); acute leukaemia was the most common underlying disease (69%) and 29% of cases received a previous allogeneic stem cell transplant. Aspergillus spp. were the most common pathogens (69%), followed by mucormycetes (22%), Cryptococcus spp. (4%) and Fusarium spp. (2%). The lung was the primary focus of fungal infection (48% of cases). The nervous system biopsy was performed in 10% of IFI-CNS, and a sinus biopsy was performed in 56% of IFI-PS (P = 0.03). The Galactomannan test on cerebrospinal fluid has been performed in 42% of IFI-CNS (30/71), and it was positive in 67%. Eighty-four pts received a first-line antifungal therapy with Amphotericine B in 58% of cases, Voriconazole in 31% and both in 11%. Moreover, 58% of patients received 2 or more lines of therapy and 38% were treated with a combination of 2 or more antifungal drugs. The median duration of antifungal therapy was 60 days (range 5-835). A surgical intervention was performed in 26% of cases but only 10% of IFI-CNS underwent neurosurgical intervention. The overall response rate to antifungal therapy (complete or partial response) was 57%, and 1-year overall survival was 32% without significant differences between IFI-CNS and IFI-PS. The overall mortality was 69% but the IFI attributable mortality was 33%. Mortality of IFI-CNS/PS remains high but, compared to previous historical data, it seems to be reduced probably due to the availability of newer antifungal drugs. The results arising from this large contemporary cohort of cases may allow a more effective diagnostic and therapeutic management of these very rare IFI complications in haematologic patients.

Neuroinfections caused by fungi

BACKGROUND

Fungal infections of the central nervous system (FIs-CNS) have become significantly more common over the past 2 decades. Invasion of the CNS largely depends on the immune status of the host and the virulence of the fungal strain. Infections with fungi cause a significant morbidity in immunocompromised hosts, and the involvement of the CNS may lead to fatal consequences.

METHODS

One hundred and thirty-five articles on fungal neuroinfection in PubMed, Google Scholar, and Cochrane databases were selected for review using the following search words: "fungi and CNS mycoses", CNS fungal infections", "fungal brain infections", " fungal cerebritis", fungal meningitis", "diagnostics of fungal infections", and "treatment of CNS fungal infections". All were published in English with the majority in the period 2000-2018. This review focuses on the current knowledge of the epidemiology, clinical presentations, diagnosis, and treatment of selected FIs-CNS.

RESULTS

The FIs-CNS can have various clinical presentations, mainly meningitis, encephalitis, hydrocephalus, cerebral abscesses, and stroke syndromes. The etiologic factors of neuroinfections are yeasts (Cryptococcus neoformans, Candida spp., Trichosporon spp.), moniliaceous moulds (Aspergillus spp., Fusarium spp.), Mucoromycetes (Mucor spp., Rhizopus spp.), dimorphic fungi (Blastomyces dermatitidis, Coccidioides spp., Histoplasma capsulatum), and dematiaceous fungi (Cladophialophora bantiana, Exophiala dermatitidis). Their common route of transmission is inhalation or inoculation from trauma or surgery, with subsequent hematogenous or contiguous spread. As the manifestations of FIs-CNS are often non-specific, their diagnosis is very difficult. A fast identification of the etiological factor of neuroinfection and the application of appropriate therapy are crucial in preventing an often fatal outcome. The choice of effective drug depends on its extent of CNS penetration and spectrum of activity. Pharmaceutical formulations of amphotericin B (AmB) (among others, deoxycholate-AmBd and liposomal L-AmB) have relatively limited distribution in the cerebrospinal fluid (CSF); however, their detectable therapeutic concentrations in the CNS makes them recommended drugs for the treatment of cryptococcal meningoencephalitis (AmBd with flucytosine) and CNS candidiasis (L-AmB) and mucormycosis (L-AmB). Voriconazole, a moderately lipophilic molecule with good CNS penetration, is recommended in the first-line therapy of CNS aspergillosis. Other triazoles, such as posaconazole and itraconazole, with negligible concentrations in the CSF are not considered effective drugs for therapy of CNS fungal neuroinfections. In contrast, clinical data have shown that a novel triazole, isavuconazole, achieved considerable efficacy for the treatment of some fungal neuroinfections. Echinocandins with relatively low or undetectable concentrations in the CSF do not play meaningful role in the treatment of FIs-CNS.

CONCLUSION

Although the number of fungal species causing CNS mycosis is increasing, only some possess well-defined treatment standards (e.g., cryptococcal meningitis and CNS aspergillosis). The early diagnosis of fungal infection, accompanied by identification of the etiological factor, is needed to allow the selection of effective therapy in patients with FIs-CNS and limit their high mortality.

Advances in the diagnosis and treatment of fungal infections of the CNS

Fungal infections of the CNS are challenging to treat and their optimal management requires knowledge of their epidemiology, host characteristics, diagnostic criteria, and therapeutic options. Aspergillus and Cryptococcus species predominate among fungal infections of the CNS. Most of these fungi are ubiquitous, but some have restricted geographical distribution. Fungal infections of the CNS usually originate from primary sites outside the CNS (eg, fungal pneumonia) or occur after inoculation (eg, invasive procedures). Most patients with these infections have immunodeficiencies, but immunocompetent individuals can also be infected through heavy exposure. The infecting fungi can be grouped into moulds, yeasts, and dimorphic fungi. Substantial progress has been made with new diagnostic approaches and the introduction of novel antifungal drugs, but fungal infections of the CNS are frequently lethal because of diagnostic delays, impaired drug penetration, resistance to antifungal treatments, and inadequate restoration of immune function. To improve outcomes, future research should advance diagnostic methods (eg, molecular detection and fungus identification), develop antifungal compounds with enhanced CNS-directed efficacy, and further investigate crucial host defence mechanisms.