Performance of Aspergillus PCR in cerebrospinal fluid for the diagnosis of cerebral aspergillosis

A case of intracranial infection caused by Aspergillus flavus originating from chronic otitis media

Central nervous system (CNS) aspergillosis is uncommon in immunocompetent patients. We present a 64-year-old man with chronic otitis media and uncontrolled diabetes. Aspergillus flavus was identified in cerebrospinal fluid via metagenomics next-generation sequencing technology. Initial voriconazole treatment offered limited relief, but personalized dosage adjustments, guided by drug concentration, led to remission. This case underscores the importance of diverse diagnostic approaches and tailored therapy for CNS Aspergillus infections.

Hematopoietic stem cell transplantation and the noncytomegalovirus herpesviruses

Although hematopoietic stem cell transplantation (HSCT) and other cellular therapies have significantly improved outcomes in the management of multiple hematological and nonhematological malignancies, the resulting impairment in humoral and cellular response increases the risk for opportunistic infection as an undesirable side effect. With their ability to establish latent infection and reactivate when the host immune system is at its weakest point, the Herpesviridae family constitutes a significant proportion of these opportunistic pathogens. Despite recent advancements in preventing and managing herpesvirus infections, they continue to be a common cause of significant morbidity and mortality in transplanted patients. Herein, we aim to provide and update on herpesvirus other than cytomegalovirus (CMV) affecting recipients of HSCT and other cellular therapies.

A Multiplex PCR and DNA-Sequencing Workflow on Serum for the Diagnosis and Species Identification for Invasive Aspergillosis and Mucormycosis

There has been significant increase in the use of molecular tools for the diagnosis of invasive aspergillosis (IA) and mucormycosis. However, their range of detection may be too limited as species diversity and coinfections are increasing. Here, we aimed to evaluate a molecular workflow based on a new multiplex PCR assay detecting the whole Aspergillus genus and the Mucorales order followed by a species-specific PCR or a DNA-sequencing approach for IA and/or mucormycosis diagnosis and species identification on serum. Performances of the MycoGENIE Aspergillus spp./Mucorales spp. duplex PCR kit were analyzed on a broad range of fungal strains and on sera from high-risk patients prospectively over a 12-month period. The kit allowed the detection of nine Aspergillus species and 10 Mucorales (eight genera) strains assessed. No cross-reactions between the two targets were observed. Sera from 744 patients were prospectively analyzed, including 35 IA, 16 mucormycosis, and four coinfections. Sensitivity varies from 85.7% (18/21) in probable/proven IA to 28.6% (4/14) in COVID-19-associated pulmonary aspergillosis. PCR-positive samples corresponded to 21 A. fumigatus, one A. flavus, and one A. nidulans infections. All the disseminated mucormycosis were positive in serum (14/14), including the four Aspergillus coinfections, but sensitivity fell to 33.3% (2/6) in localized forms. DNA sequencing allowed Mucorales identification in serum in 15 patients. Remarkably, the most frequent species identified was Rhizomucor pusillus (eight cases), whereas it is barely found in fungal culture. This molecular workflow is a promising approach to improve IA and mucormycosis diagnosis and epidemiology.

Cerebral vasculitis due to Aspergillus spp. in immunocompromised patients: literature review

OBJECTIVES

Invasive aspergillosis is a threat for immunocompromised patients. We present a case series of aggressive cerebral vasculitis caused by Aspergillus spp. infection in immunocompromised patients.

METHODS

We present a retrospective case series of three autopsy-proven invasive cerebral aspergillosis with diffuse vasculitis affecting large caliber cerebral vessels.

RESULTS

Three patients were immunosuppressed: one on rituximab, one on corticosteroids, and one with a renal transplant. Two of these patients were diagnosed with cerebral aspergillosis on postmortem.

CONCLUSION

Aspergillus cerebral vasculitis is a rare form of invasive aspergillosis that should be considered in an immunocompromised individual with suggestive lesions on imaging. It should be suspected as a possible cause of aseptic neutrophil meningitis.

Metagenomic Next-Generation Sequencing of Cerebrospinal Fluid for the Diagnosis of Cerebral Aspergillosis

Purpose: Cerebral aspergillosis (CA) is a rare but often fatal, difficult-to-diagnose, opportunistic infection. The utility of metagenomic next-generation sequencing (mNGS) for diagnosis of CA is unclear. We evaluated the usefulness of mNGS of the cerebrospinal fluid (CSF) for the diagnosis of CA. Methods: This prospective study involved seven consecutive patients with confirmed CA in whom CSF mNGS was performed. Serum (1→3)-β-D-glucan and galactomannan levels were determined, and histopathological examination and mNGS of the CSF were conducted. CSF specimens from three non-infected patients were used as positive controls. Results: mNGS of the CSF was positive in six of the seven confirmed CA cases (85.71% sensitivity). In the cryptococcal meningitis group (control), mNGS of the CSF was positive for Aspergillus in two patients (84.62% specificity). The positive likelihood ratio, negative likelihood ratio, and Youden's index of mNGS for CA in the CSF were 5.565, 0.169, and 0.7, respectively. Among the six mNGS-positive cases, more than two Aspergillus species were found in four (4/6, 66.67%). In the positive controls, the addition of one A. fumigatus spore yielded a standardised species-specific read number (SDSSRN) of 25.45 by mNGS; the detection rate would be 0.98 if SDSSRN was 2. Conclusion: mNGS facilitates the diagnosis of CA and may reduce the need for cerebral biopsy in patients with suspected CA. Trial Registration Number: Chinese Clinical Trial Registry, ChiCTR1800020442.

Practice Guidelines for the Diagnosis of COVID-19-Associated Pulmonary Aspergillosis in an Intensive Care Setting

Coronavirus disease-2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) is a new disease characterized by secondary Aspergillus mold infection in patients with COVID-19. It primarily affects patients with COVID-19 in critical state with acute respiratory distress syndrome, requiring intensive care and mechanical ventilation. CAPA has a higher mortality rate than COVID-19, posing a serious threat to affected individuals. COVID-19 is a potential risk factor for CAPA and has already claimed a massive death toll worldwide since its outbreak in December 2019. Its second wave is currently progressing towards a peak, while the third wave of this devastating pandemic is expected to follow. Therefore, an early and accurate diagnosis of CAPA is of utmost importance for effective clinical management of this highly fatal disease. However, there are no uniform criteria for diagnosing CAPA in an intensive care setting. Therefore, based on a review of existing information and our own experience, we have proposed new criteria in the form of practice guidelines for diagnosing CAPA, focusing on the points relevant for intensivists and pulmonary and critical care physicians. The main highlights of these guidelines include the role of CAPA-appropriate test specimens, clinical risk factors, computed tomography of the thorax, and non-culture-based indirect and direct mycological evidence for diagnosing CAPA in the intensive care unit. These guidelines classify the diagnosis of CAPA into suspected, possible, and probable categories to facilitate clinical decision-making. We hope that these practice guidelines will adequately address the diagnostic challenges of CAPA, providing an easy-to-use and practical algorithm to clinicians for rapid diagnosis and clinical management of the disease.

Approach to Neurologic Complications in the Immunocompromised Patient

Neurologic complications are common in immunocompromised patients, including those with advanced human immunodeficiency virus, transplant recipients, and patients on immunomodulatory medications. In addition to the standard differential diagnosis, specific pathogens and other conditions unique to the immunocompromised state should be considered in the evaluation of neurologic complaints in this patient population. A thorough understanding of these considerations is critical to the inpatient neurologist in contemporary practice, as increasing numbers of patients are exposed to immunomodulatory therapies. In this review, we provide a chief complaint-based approach to the clinical presentations and diagnosis of both infectious and noninfectious complications particular to immunocompromised patients.

Neurologic Infections in Patients on Immunomodulatory and Immunosuppressive Therapies

PURPOSE OF REVIEW

Both broadly immunosuppressive medications and selective immunomodulatory agents that act on particular components of the immune system are increasingly used in the treatment of neurologic and non-neurologic diseases. These therapies predispose patients to particular infections, some of which may affect the nervous system. Therefore, familiarity with the clinical and radiologic features of neurologic infections associated with specific immunomodulatory therapies is of importance for the practicing neurologist. This article reviews these neuroinfectious conditions, as well as other neurologic complications unique to transplant recipients and other patients who are immunocompromised.

RECENT FINDINGS

Diagnosis of infectious pathogens in patients who are immunocompromised may be particularly challenging because a decreased immune response can lead to atypical imaging or laboratory findings. Next-generation sequencing and other novel diagnostic modalities may improve the rate of early identification of neurologic infections in patients who are immunocompromised and ultimately ameliorate outcomes in this vulnerable population.

SUMMARY

A broad range of bacterial, viral, fungal, and parasitic infections of the nervous system can complicate solid organ and hematopoietic cell transplantation as well as other forms of immunocompromise. In addition to neurologic infections, such patients are at risk of neurotoxic and neuroinflammatory complications related to immunomodulatory and immunosuppressive therapies. Early recognition of infectious and noninfectious complications of immunocompromise is essential to guide appropriate treatment, which can include antimicrobial therapy and, in some cases, withdrawal of the predisposing medication with a transition to an alternative regimen.

Next-Generation Sequencing-Based Decision Support for Intensivists in Difficult-to-Diagnose Disease States: A Case Report of Invasive Cerebral Aspergillosis

Aspergillus spp. are widespread environmental pathogens that can induce invasive aspergillosis, especially in immunocompromised patients. An 86-year-old female patient presented with a rare case of invasive cerebral aspergillosis. The aspergilloma invaded the intracranial region originating from the ethmoidal sinus and the orbital apex. In contrast to routine diagnostic procedures, next-generation sequencing (NGS) was able to identify the fungal pathogen in the cerebrospinal fluid as well as in plasma samples, supporting the biopsy-based diagnosis of invasive cerebral aspergillosis. Therefore, NGS-based diagnostics may be of particular importance for difficult-to-diagnose disease states, when conventional diagnostic procedures fail.

Clinical manifestations, diagnosis, and treatment outcome of CNS aspergillosis: A systematic review of 235 cases

Aspergillus is a ubiquitous ascomycete that can cause a variety of clinical presentations depending on immune status. Central nervous system aspergillosis is a fatal disease with non-specific clinical features. The aim of this systematic review was to evaluate the epidemiology, clinical features, diagnosis and therapeutic interventions in CNS aspergillosis patients. We also aimed to examine the possible predictors of mortality in neuroaspergillosis. Literature search was performed in Medline, PubMed, and Google scholar and all patients≥18 years with proven CNS aspergillosis were included. A total of 175 articles (235 patients) were included in the final analysis. Their mean age was 51 years and the majority were male (57.4%). Overall case-fatality was 45.1%. Aspergillus fumigatus was the most common species (70.8%) followed by A. flavus (18.6%). Corticosteroids (22.6%), malignancy (19.1%) and diabetes mellitus (14%) were the most common risk factors. Neuroimaging findings included cerebral abscess (70.2%), meningitis (14%), infarction (13.2%) and mycotic aneurysm (8.9%). Disseminated disease (29.2% vs 17.8%, p 0.03), CSF hypoglycorrhachia (48.1% vs 22.2%, P: 0.001) and heightened CSF galactomannan (3.62 vs 2.0ng/ml, p 0.05), were the factors associated with poor outcome in neuroaspergillosis. Persons infected with Aspergillus flavus (13.1% vs 3.1%, P: 0.01), and having been treated with Voriconazole (51.9% vs 29.2%, P: 0.004) were more likely to survive. Our review will provide insight into the different spectrums of CNS aspergillosis. Notwithstanding the promising role of Voriconazole, future work is required to ascertain the role of combination antifungal therapy.

Update on fungal infections of the central nervous system: emerging pathogens and emerging diagnostics

PURPOSE OF REVIEW

Fungal infections of the central nervous system (CNS) are relatively uncommon but associated with significant morbidity and mortality. We reviewed recent literature highlighting new approaches to management of these complex patients.

RECENT FINDINGS

Fungal infections are increasingly recognized as important causes of CNS disease in both immunocompromised and immunocompetent hosts. Globally, cryptococcal meningitis remains a leading cause of death in HIV-infected persons in resource-limited settings. Emerging fungal pathogens with increased virulence and resistance to numerous classes of antifungal agents have been identified and represent a management challenge. Newer diagnostic techniques focused on antigen detection or molecular amplification of fungal pathogens offer promise in the expediated diagnosis and treatment of CNS fungal infections.

SUMMARY

Meningitis and brain abscess because of invasive fungal pathogens are frequently fatal infections. Newer laboratory tests allowing antigen detection or molecular amplification from cerebrospinal fluid are more sensitive than culture and allow earlier initiation of effective therapy.

Chronic Meningitis

PURPOSE OF REVIEW

This article describes the clinical presentation, diagnostic approach (including the use of novel diagnostic platforms), and treatment of select infectious and noninfectious etiologies of chronic meningitis.

RECENT FINDINGS

Identification of the etiology of chronic meningitis remains challenging, with no cause identified in at least one-third of cases. Often, several serologic, CSF, and neuroimaging studies are indicated, although novel diagnostic platforms including metagenomic deep sequencing may hold promise for identifying organisms. Infectious etiologies are more common in those at risk for disseminated disease, specifically those who are immunocompromised because of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), transplantation, or immunosuppressant medications. An important step in identifying the etiology of chronic meningitis is assembling a multidisciplinary team of individuals, including those with specialized expertise in ophthalmology, dermatology, rheumatology, and infectious diseases, to provide guidance regarding diagnostic procedures.

SUMMARY

Chronic meningitis is defined as inflammation involving the meninges that lasts at least 4 weeks and is associated with a CSF pleocytosis. Chronic meningitis has numerous possible infectious and noninfectious etiologies, making it challenging to definitively diagnose patients. Therefore, a multifaceted approach that combines history, physical examination, neuroimaging, and laboratory analysis, including novel diagnostic platforms, is needed. This article focuses on key aspects of the evaluation of and approach to patients with chronic meningitis. Specific infectious etiologies and differential diagnoses of subacute and chronic meningitis, including noninfectious etiologies, are addressed.

Galactomannan and PCR in the Central Nervous System to Detect Invasive Mold Disease - A Retrospective Analysis in Immunocompromised Children

Invasive mold disease (IMD) of the central nervous system (CNS) is a severe infectious complication in immunocompromised patients, but early microbiological diagnosis is difficult. As data on the value of biomarkers in the CNS are scarce, in particular in children, we retrospectively analyzed the performance of galactomannan (GM) and PCR assays in CNS samples of 15 children with proven and probable CNS IMD and of 32 immunocompromised children without fungal infection. Galactomannan in the cerebrospinal fluid (CSF) was assessed in nine of the 15 pediatric patients and was positive in five of them. Polymerase chain reaction (PCR) was performed in eight of the 15 patients and detected nucleic acids from molds in six patients. Galactomannan and PCR in CNS samples were the only positive microbiologic parameter in the CNS in three and two patients, respectively. In four patients, PCR specified the pathogen detected in microscopy. Galactomannan and PCR results remained negative in the CSF of all immunocompromised children without evidence for CNS IMD. Our data suggest that GM and PCR in CNS specimens are valuable additional tools in diagnosing CNS IMD and should be included in the work up of all pediatric patients with suspected mold disease of the CNS.

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.

Special scenarios in the management of central nervous system aspergillosis: a case series and review of literature

Aspergillus is a rare but important opportunistic pathogen to invade the central nervous system (CNS). It is a significant pathogen of not only immunocompromised but also immunocompetent patients. Its manifestations are pleiotropic, reflecting multiple mechanisms of pathogenesis and host interactions. Despite significant advances in diagnostic methods and therapeutic options, the mortality remains high. Several advances have been made in medications and surgical management, yet, current treatment practices lack uniformity. Patient woes are further heightened by the high costs of treatment and prolonged duration of therapy. In view of the challenging aspects of this disease, we present a short review of four challenging cases touching on the varied aspects of management of CNS aspergillosis covering pathogenesis, diagnostic pitfalls, surgical and medical options and evidence-based guidelines for the management of the same.

[Infections of the central nervous system by protozoa, helminths and fungi]

A plethora of different parasites and fungi can lead to infections of the central nervous system (CNS) and cause different clinical symptoms and outcomes depending on the pathogen and the anatomic location of the infection. The diagnosis and treatment of these eukaryotic infections is challenging. The prevalence of CNS infections depends on many factors, including geographical location, living conditions, genetic background and the immune status of the individual. In Germany, infections of the CNS by fungi and parasites are rare but can lead to considerable morbidity. Some parasitic and fungal CNS infections are becoming increasingly more prevalent and clinically relevant due to the increasing number of immunocompromised people. Case fatality rates of these infections, which are difficult to diagnose and to treat, are high. This article provides an overview of a subjective selection of parasitic and fungal infections of the CNS relevant to clinical practice in Germany and presents the diagnostic and therapeutic options.

Neurological Complications Occurring After Liver Transplantation: Role of Risk Factors, Hepatic Encephalopathy, and Acute (on Chronic) Brain Injury

Orthotopic liver transplantation (LT) remains the only way to definitively cure patients with the most severe liver diseases. Because the survival rate is now fairly high, important questions about neurological sequelae or quality of life after LT have emerged. Indeed, LT represents a peculiar situation because up to 30% of patients present with neurological symptoms after LT compared with only 4% after cardiac transplant and 0.5% after renal transplant. These postoperative neurological symptoms have long been interpreted as sequelae of hepatic encephalopathy (HE). However, postoperative decompensation of an unknown cerebral condition due to the pathophysiology of cirrhosis or undiagnosed neurodegenerative disorders or aging constitute other possibilities that are underrecognized. Some patients who undergo LT for acute liver failure and patients with cirrhosis without episodes of HE and without any previous cerebral alteration also display post-LT neurological symptoms. This latter situation speaks in favor of a direct adverse effect of either general anesthesia, the surgical procedure, or factors related to the postoperative intensive care unit (ICU) environment. The role of inflammation, which has been described in the ICU setting, could also be a crucial determinant. In this review, we will discuss the neurological complications associated with LT, the neurocognitive complications after LT, and how to assess the LT-related neurological or neurocognitive complications. Furthermore, we will review the various hypotheses surrounding post-LT neurocognitive impairment and will conclude with recommendations for future directions.