Fungal brain infections

Retrovirus-Derived RTL9 Plays an Important Role in Innate Antifungal Immunity in the Eutherian Brain

Retrotransposon Gag-like (RTL) genes play a variety of essential and important roles in the eutherian placenta and brain. It has recently been demonstrated that RTL5 and RTL6 (also known as sushi-ichi retrotransposon homolog 8 (SIRH8) and SIRH3) are microglial genes that play important roles in the brain's innate immunity against viruses and bacteria through their removal of double-stranded RNA and lipopolysaccharide, respectively. In this work, we addressed the function of RTL9 (also known as SIRH10). Using knock-in mice that produce RTL9-mCherry fusion protein, we examined RTL9 expression in the brain and its reaction to fungal zymosan. Here, we demonstrate that RTL9 plays an important role, degrading zymosan in the brain. The RTL9 protein is localized in the microglial lysosomes where incorporated zymosan is digested. Furthermore, in Rtl9 knockout mice expressing RTL9ΔC protein lacking the C-terminus retroviral GAG-like region, the zymosan degrading activity was lost. Thus, RTL9 is essentially engaged in this reaction, presumably via its GAG-like region. Together with our previous study, this result highlights the importance of three retrovirus-derived microglial RTL genes as eutherian-specific constituents of the current brain innate immune system: RTL9, RTL5 and RTL6, responding to fungi, viruses and bacteria, respectively.

Clinicomycological overview of brain abscess in a tertiary care center: A 38 year retrospection: Fungal brain abscess

INTRODUCTION

Brain abscesses (BA) form approximately 8% of intracranial masses in developing and 1-2% in western countries. Fungal BA (FBA) are aggressive and represent a catastrophic manifestation compared to protozoan and bacterial BA. Diagnosis of FBA is rare and usually done postmortem.

OBJECTIVES

The present retrospective study analyses the clinico-mycological aspects of FBA presented to our neurosurgical services over a period of 38 years, from January 1979 to April 2017.

MATERIALS AND METHODS

Patients diagnosed as definitive cases of FBA were included in the study. Clinico- demographic and microbiological data were collected from medical records. BA pus was examined for fungal etiology using standard microbiological procedures.

RESULTS

During the period of 38 years out of total 2,916 brain abscesses, 29 cases of FBA were diagnosed with an overall incidence rate of 0.99% per year. Cladophialophora bantiana (44%) was the most predominant isolate followed by Aspergillus spp and others. Male preponderance was seen with a male:female ratio of 4.8:1. There was no predilection for any age group. Headache, limb weakness and fever were the most common presentations. Amphotericin B was given in 44.8% of cases. Craniotomy with excision (48.2%) was the predominant surgical management. Outcome was fatal in 62% of the cases.

CONCLUSION

Neurotropic C. bantiana is the predominant isolate causing fungal brain abscess. The incidence and trends of fungi causing brain abscess do not show significant change. Young immunocompetent outdoor working males were predominantly susceptible to fungal infection. Advance in the diagnostic modalities show promising in diagnosis of FBA. High index of suspicion with early diagnosis, prompt antifungal therapy and aggressive surgical management is required as FBA are associated with high mortality rate.

Impact of Surgical and Medical Treatment on Survival of Patients with Cerebral Aspergillosis: Systematic Review of the Literature

OBJECTIVE

Cerebral aspergillosis carries a high mortality. Rapid diagnosis and treatment can increase survival, but symptoms and imaging findings are nonspecific. The literature on cerebral aspergillosis consists mostly of case reports and case series and lacks large-scale review of data.

METHODS

We performed a review of the literature using PubMed in March 2019. We recorded the year of publication, age and sex of patients, neurosurgical involvement, the antifungals administered, use of intrathecal antifungals, and the outcome of patients. The relationships among variables were tested using bivariant statics and linear regression.

RESULTS

A total of 324 studies met the eligibility criteria, and 198 studies including 248 patients were included. Surgical resection (odds ratio [OR], 0.45; 95% confidence interval [CI], 0.25-0.80; P < 0.01) and administration of voriconazole (OR, 0.32; 95% CI, 0.18-0.55; P < 0.001) or itraconazole (OR, 0.36; 95% CI, 0.16-0.72; P < 0.001) were shown to be significantly associated with survival.

CONCLUSIONS

Given the significant survival benefits for patients who received voriconazole and surgical intervention, we suggest early antifungal medical treatment and resection.

Infectious Disease Complications in Patients with Cancer

Critically ill patients with cancer are vulnerable to infections because of the underlying malignancy, tumor-directed therapy, immunosuppression, breaches in mucosa or skin, malnutrition, and other factors. Neutropenia remains the most important risk factor for infection. Infectious complications occurring in critically ill patients with cancer can affect the bloodstream, lungs, gastrointestinal tract, central nervous system, urinary tract, and the skin. Pneumonias are the leading cause of infection in patients with cancer admitted to the intensive care unit. Consideration of opportunistic pathogens in the differential diagnosis is important in patients with impaired cellular and/or humoral immunity or compromised splenic function.

Brain aspergilloma in an immunocompetent individual: A case report

Background:

Aspergillosis is caused by fungi from the Aspergillus species, mainly Aspergillus fumigatus. Patients with aspergillosis typically have an underlying immunosuppression, and it is rare within the central nervous system (CNS) in an immunocompetent host. The mortality rate is as high as 90% if untreated, and the diagnosis is usually delayed due to nonspecific clinical presentation. This study described a case of CNS aspergillosis in an immunocompetent patient, through which we sought to discuss the current knowledge regarding brain Aspergillus focusing in the immunocompetent host.

Case Description:

A 45-year-old male presented with 2 years of low-intensity headache and history of chronic sinusitis with epistaxis in the left nostril. Fifteen days before admission, he had high-intensity headache, episodes of transient aphasia, and seizure. Imaging showed a contrast-enhancing mass within the left maxillary sinus and another lesion in the left frontal lobe. The left frontal craniotomy was conducted, and complete resection was achieved. Biopsy identified A. fumigatus, and antifungal therapy was initiated. After 2 weeks, a new lesion was detected in the right frontal lobe, and the patient underwent a new procedure with complete lesion resection. Follow-up at 3 weeks did not reveal any evidence of residual or recurrent disease. The patient did not develop neurological complaints and was referred for resection of the remaining lesion by an otolaryngology team.

Conclusion:

Being one of the few cases reporting a successful outcome for brain aspergilloma in an immunocompetent patient after complete surgical resection and amphotericin B and itraconazole therapy, we sought to reveal novel insight into brain aspergillosis.

Candida meningitis in neurosurgical patients: a single-institute study of nine cases over 7 years

Candida meningitis in neurosurgical patients is relatively unusual but is associated with a high mortality rate. We present our experience with this infection and discuss the clinical characteristics, treatment options and outcomes. We retrospectively reviewed neurosurgical patients with multiple positive cerebrospinal fluid (CSF) culture results in our hospital from January 2013 to December 2019. Nine patients were available for review according to our inclusion and exclusion criteria. Four species of Candida were isolated from the CSF samples and Candida albicans accounted for half of all infections. Eight infections were associated with ventricle peritoneal shunt, lumbar cistern peritoneal shunt or external ventricular drain. All of these foreign intracranial materials were removed or changed and all the patients received antifungal treatment, including fluconazole and/or voriconazole. It is associated with severe long-term outcomes in survivors and a mortality rate that reaches 11.1%. Prior treatments with broad-spectrum and high-grade antibiotics and anaemia are possible risk factors for Candida meningitis. We advise that foreign intracranial material should be removed or changed as early as possible and the timing of re-shunt operation can be 1 month after control of Candida meningitis has been achieved, with several negative CSF culture results.

Central Nervous System Fungal Infection-Related Stroke: A Descriptive Study of Mold and Yeast-Associated Ischemic Stroke

OBJECTIVE

Central nervous system (CNS) ischemic events caused by fungal infections are rare, and clinical characteristics of these ischemic events are largely unknown. The objective of this manuscript is to highlight characteristics of fungal-related strokes and describe possible mechanistic differences between CNS mold and yeast infection-related strokes.

METHODS

We report a single-center retrospective case series of all adult patients who presented with concurrent CNS fungal infection and stroke between 2010 and 2018. Patients believed to have a stroke etiology due to cardioembolic, atheroembolic, or strokes nontemporally associated with a CNS fungal infection and those with incomplete stroke workups were excluded from analysis.

RESULTS

Fourteen patients were identified with ischemic stroke and concurrent CNS fungal infection without other known ischemic stroke etiology. Eight patients had a CNS yeast infection, and 6 had a CNS mold infection. All patients presented with recurrent or progressive stroke symptoms. Six patients were immune-compromised. Four patients admitted to intravenous drug use. All yeast infections were identified by cerebrospinal fluid culture or immunologic studies while all but one of the mold infections required identification by tissue biopsy. Leptomeningeal enhancement was only associated with CNS yeast infections, while basal ganglia stroke was only associated with CNS mold infections.

CONCLUSION

Ischemic stroke secondary to CNS fungal infections should be considered in patients with recurrent or progressive cryptogenic stroke, regardless of immune status and cerebrospinal fluid profile. CNS yeast and mold infections have slightly different stroke and laboratory characteristics and should have a distinct diagnostic method. Depending on clinical suspicion, a thorough diagnostic approach including spinal fluid analysis and biopsy should be considered.

Intracranial aspergillosis amongst immunocompetent patients: An experience with combined surgical and medical management of 18 patients

OBJECTIVE

Fungal infections of central nervous system (CNS) commonly affect immunocompromised patients, however, recently such cases have been reported even amongst immunocompetent patients.

PATIENTS & METHODS

In this study, we retrospectively analyzed outcome of 18 immunocompetent patients with histopathologically proven intracranial Aspergillosis undergoing combined surgical and medical management.

RESULTS

The age of patients ranged from 5-65 years. Fourteen out of 18 patients had well defined lesions while 4 had diffuse disease. Paranasal sinuses were involved in 8 & cavernous sinus in 3 patients. Six patients had hydrocephalus. Four patients developed infarcts during their clinical course. Surgical interventions included gross (n = 4) or subtotal excision (n = 8), decompressive craniectomy & biopsy of lesion (n = 4), biopsy only (n = 2) and ventriculoperitoneal shunt placement (n = 6). All patients received postoperative antifungal therapy. The duration of follow up ranged from 10-60 months. Overall mortality was 44.4%. Mortality amongst patients undergoing gross total and subtotal excision was 25% & 50% respectively. Patients undergoing DC had a mortality of 25%. Both patients undergoing only biopsy died. Hydrocephalus was associated with a very high mortality (83.3%). Amongst surviving patients (n = 10), 6 patients became disease free & rest 4 had stable disease at last follow up.

CONCLUSIONS

Intracranial aspergillosis is associated with high morbidity & mortality even amongst immunocompetent patients. An aggressive multidisciplinary management is thus needed to improve outcome. Our study shows that a combination of surgical excision or decompressive craniectomy and antifungal therapy can be helpful in improving prognosis of these patients.

National trends in incidence, prevalence and disability-adjusted life years of invasive aspergillosis in Iran: a systematic review and meta-analysis

Objectives: We aimed to study the epidemiology, prevalence, incidence, clinical manifestations, underlying diseases, treatments, outcomes, and societal impact through disability-adjusted life years (DALYs) of IA in Iran. Methods: A random-effect meta-analytic model was fitted to estimate the prevalence and incidence of IA in Iran. We also calculated DALYs. Results: Out of 79 published studies during the past 25 years from Iran, 23 met the inclusion criteria. A total of 2947 patients were included, of whom 396 (13.4%) patients were diagnosed with IA according to EORTC/MSG and ICU criteria. The main underlying condition for IA was hematologic disorders (39.4%). A. flavus 86 (43%) was the most common isolate. The pooled prevalence and incidence rates were 20.5 (95% CI 12.5 to 29.9) and 4.8 (95% CI 2.3-8.2) per 100,000 population, respectively. Total DALYs was estimated 164.13 per 100,000 population. YLLs constitute the majority of IA burden compared to YLDs (162.80 YLLs/100,000 population vs 1.33 YLDs per 100,000 population). The highest YLL rates were found in people aged 45-49 (62.9 YLLs/100,000 population) and 30-34 years (45.2 YLLs/100,000 population), respectively. Conclusion: This study indicates an increasing burden of IA in Iran, despite the extensive use of prophylaxis, challenging the public health, especially immunocompromised patients.

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.

Medical treatment of brain aspergilloma followed by MRI: A case report

This is a brain aspergilloma case in an immunocompetent patient who suffered from a rare fungal infection transmitted from the mediastinum to the brain and eventually caused pancreatitis. This fungal infection affected the thalamus, hypothalamus, and extended to the midbrain. This case showed a good prognosis for the brain aspergilloma without need for any surgical intervention. The radiological documentation for the brain aspergilloma shows a positive response to a combination of voriconazole and Keppra.

Invasive Aspergillus terreus morphological transitions and immunoadaptations mediating antifungal resistance

Background and aims

Aspergillus terreus Thom is a pathogen of public health and agricultural importance for its seamless abilities to expand its ecological niche. The aim of this study was holistically to investigate A. terreus morphological and immunoadaptations and their implication in antifungal resistance and proliferation during infection.

Materials and methods

In-depth unstructured mining of relevant peer-reviewed literature was performed for A. terreus morphological, immune, resistance, and genetic diversity based on the sequenced calmodulin-like gene.

Results

Accessory conidia and phialidic conidia produced by A. terreus confer discrete anti-fungal resistance that ensures survivability during therapies. Interestingly, by producing unique metabolites such as Asp–melanin and terretonin, A. terreus is capable of hijacking macrophages and scavenging iron, respectively. As such, A. terreus has established a rare mechanism to mitigate phagocytosis and swing the interaction dynamics in favor of its proliferation and survival in hosts.

Conclusion

It is further unraveled that besides A. terreus genetic diversity, morphological, biochemical, and immunologic adaptations associated with conidia germination and discharge of chemical signals during infection enable masking of the host defense as an integral part of its strategy to survive and rapidly colonize hosts.

Aspergillosis of the central nervous system in a previously healthy patient that simulated Creutzfeldt-Jakob disease

BACKGROUND

The presence of Aspergillus in the central nervous system (CNS) is rare in immunocompetent patients but not in immunocompromised patients who may have a more common infection. This article describes a case of an adult immunocompetent patient with a diagnosis of cerebral aspergillosis and with a clinical process of rapidly progressive dementia which simulated a Creutzfeldt-Jakob syndrome.

CASE DESCRIPTION

A 34-year-old adult was previously healthy and had no medical history of any significance. The patient had suffered only facial trauma 8 months before admission. One month prior to admission, he showed rapidly progressing changes in his behavior and higher mental functions. He was admitted to the emergency room with an occipital headache with 2 months of history. By the time he arrived, he suffered from total disability and was prostrate. He was diagnosed with meningeal and demential syndrome in the process of being studied. After starting the diagnostic approach by investigating cerebrospinal fluid, a magnetic resonance of the skull, an electroencephalogram, a brain biopsy was indicated. The histopathological study reported the presence of the hyphae characteristics of Aspergillus. The patient died 7 days after the diagnosis.

CONCLUSION

Cerebral aspergillosis is a common aggressive disease in immunosuppressed patients. However, the disease is rare in individuals with respected immunity and in individuals with neurological impairment and a rapid and progressive deterioration of mental functions. The suspected diagnosis should always be considered given its poor prognosis and the encouraging efficacy of antifungal treatment administered in a timely manner.

Molecular diagnosis of invasive mycoses of the central nervous system

INTRODUCTION

In September 2012, the Centers for Disease Control and Prevention (CDC) began investigating an outbreak of fungal meningitis among patients who had received contaminated preservative-free methyl prednisolone acetate injections from the New England Compounding Center in Framingham, Massachusetts. Thousands of patients were potentially exposed to tainted corticosteroids, but establishing the diagnosis of fungal meningitis during the nationwide outbreak was difficult because little was known about the natural history of the disease. Areas covered: The challenges associated with this outbreak highlighted the need for rapid and reliable methodologies to assist in the diagnosis of invasive mycoses of the central nervous system (IMCNS), which may be devastating and difficult to treat. In this paper, we review the causative agents of these potentially-lethal infections, which include cryptococcal meningitis, cerebral aspergillosis, and hematogenous Candida meningoencephalitis. Expert commentary: While microscopy, culture, and histopathologic identification of fungal pathogens remain the gold standard for diagnosis, new platforms and species-specific assays have recently emerged, including lateral flow immunoassays (LFA), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and multiplex PCR in conjunction with magnetic resonance (MR) to potentially aid in the diagnosis of IMCNS.

Successful treatment of primary cerebral mucormycosis: Role of microbiologist

Fungal brain abscess is rare with a rapidly progressive disease with fulminant course and invariably fatal outcome, unless diagnosed early and treated rapidly. We report a 56-year-old woman diagnosed to have fungal abscess who recovered completely following amphotericin B treatment. She presented with weakness of the right hand, deviation of mouth to left and aphasia for 2 days. Computed tomography of the brain revealed a left frontal capsuloganglionic hypodense lesion. Stereotactic biopsy was performed, and microbiological confirmation of non-septate fungal hyphae from pus from aspirate within 2 h helped initiate timely and appropriate treatment leading to cure. Histopathology and culture later confirmed mucormycosis.

Fungal Infection in the Brain: What We Learned from Intravital Imaging

Approximately 1.2 billion people suffer from fungal diseases worldwide. Arguably, the most serious manifestation occurs when pathogenic fungi infect the brain, often causing fatal meningoencephalitis. For most fungi, infection occurs via the vascular route. The organism must first be arrested in the brain microvasculature and transmigrate into the brain parenchyma across the blood–brain barrier. As a result, host immune cells are recruited into the brain to contain the fungi. However, it remains poorly understood how fungi traffic to, and migrate into the brain and how immune cells interact with invading fungi in the brain. A new era of intravital fluorescence microscopy has begun to provide insights. We are able to employ this powerful approach to study dynamic interactions of disseminating fungi with brain endothelial cells as well as resident and recruited immune cells during the brain infection. In this review, with a focus on Cryptococcus neoformans, we will provide an overview of the application of intravital imaging in fungal infections in the brain, discuss recent findings and speculate on possible future research directions.

Management of granulomatous cerebral aspergillosis in immunocompetent adult patients: a review

Cerebral aspergillosis, is an infrequent, opportunistic infection of the central nervous system that accounts for 5-10% of all intracranial fungal pathology. It is uncommon in immunocompetent patients and has a significant disease burden, with high morbidity and mortality, even with appropriate treatment. Basic principles of abscess management should be employed, including aspiration and targeted anti-fungal therapy for 12-18 months. However, reported outcomes with a purely minimally invasive approach are poor and there should be a low threshold for surgical excision, especially in resource poor settings and in patients with deteriorating neurology harbouring sizeable masses. Evidence favouring gross total excision over subtotal resection is lacking, however. It is notable that these recommendations are largely based on retrospective case series and isolated case reports. There is a need therefore for international collaboration to evaluate management strategies for immunocompetent patients with cerebral aspergillosis.

In vitro antifungal activity of antipsychotic drugs and their combinations with conventional antifungals against Scedosporium and Pseudallescheria isolates

In the present study, in vitro antifungal activities of five antipsychotic drugs (i.e., chlorpromazine hydrochloride, CPZ; trifluoperazine hydrochloride, TPZ; amantadine hydrochloride; R-(-)-deprenyl hydrochloride, and valproic acid sodium salt) and five conventional antifungal drugs (i.e., amphotericin B, AMB; caspofungin, CSP; itraconazole; terbinafine, TRB and voriconazole, VRC) were investigated in broth microdilution tests against four clinical and five environmental Scedosporium and Pseudallescheria isolates. When used alone, phenothiazines CPZ and TPZ exerted remarkable antifungal effects. Thus, their in vitro combinations with AMB, CSP, VRC, and TRB were also examined against the clinical isolates. In combination with antifungal agents, CPZ was able to act synergistically with AMB and TRB in cases of one and two isolates, respectively. In all other cases, indifferent interactions were revealed. Antagonism was not observed between the tested agents. These combinations may establish a more effective and less toxic therapy after further in vitro and in vivo studies for Scedosporium and Pseudallescheria infections.

Evaluation of candidal colonization and specific humoral responses against Candida albicans in patients with psoriasis

BACKGROUND

Psoriasis is an inflammatory skin disease that can considerably affect a patient's quality of life. Environmental and genetic factors, as well as superantigens and toxins from Candida species, may play various roles in the exacerbation and persistence of psoriasis. In the present study, we evaluated candidal colonization and specific humoral responses against Candida albicans in patients with psoriasis.

METHODS

A total of 100 patients with psoriasis vulgaris and 50 healthy control individuals were enrolled in the study. Skin and oral specimens from all participants were cultured on CHROMagar Candida medium. Isolated yeast-like fungi were identified using the sequence of the D1/D2 domain of the 26S rRNA gene. Enzyme-linked immunosorbent assays (ELISAs) were used to detect immunoglobulin M (IgM), IgA, and IgG antibodies against C. albicans in sera of patients and healthy individuals.

RESULTS

Candida species were isolated from the skin of 15% of patients and 4% of controls and from oral specimens of 60% of patients and 20% of controls. There was a significant difference in candidal colonization between patients and controls (P < 0.05). Serum IgM, IgA, and IgG levels against C. albicans were significantly lower in patients with psoriasis than in controls (P < 0.05). There was no significant association between serum levels of specific antibodies against C. albicans or the frequency of candidal colonization with the clinical severity of the disease (P > 0.05).

CONCLUSIONS

The results of the present study show a higher rate of candidal colonization in patients with psoriasis in comparison with controls and a reduction in humoral immune responses in patients.

Evaluation of Candida Colonization and Specific Humoral Responses against Candida albicans in Patients with Atopic Dermatitis

The aim of this study was to assess the candidal colonization and specific humoral responses against Candida albicans in patients with atopic dermatitis. One hundred patients with atopic dermatitis and 50 healthy individuals were enrolled in the study. Skin and oral specimens from all participants were cultured on CHROMagar Candida medium. Isolated yeasts were identified by using the sequence of the D1/D2 domain of the 26S rRNA gene. ELISA was used for detection of IgM, IgA, and IgG antibodies against C. albicans in sera of participants. Candida species were isolated from the skin and oral cavity of 31% of the patients and 12% of the controls. There was no significant difference between Candida colonization in patients and controls (P>0.05). Candida albicans was isolated from the skin and oral cavity of 23% of the patients and 6% of the controls (P< 0.05). There were no significant differences between serum levels of IgM and IgA in patients and controls (P>0.05). Serum level of IgG was significantly lower in patients than in controls (P<0.05). Type of Candida colonization can change in patients with atopic dermatitis. In addition, these patients have abnormalities in the production of antibodies against Candida albicans that may have a role in the pathogenesis of atopic dermatitis.

Infektionen

In diesem Kapitel werden zunächst die für die Neurointensivmedizin wesentlichen bakteriellen Infektionen (Meningitis, spinale und Hirnabszesse, Spondylodiszitis, septisch-embolische Herdenzephalitis) abgehandelt, die trotz gezielt eingesetzter Antibiotika und neurochirurgischer Therapieoptionen noch mit einer erheblichen Morbidität und Mortalität behaftet sind. Besonderheiten wie neurovaskuläre Komplikationen, die Tuberkulose des Nervensystems, Neuroborreliose, Neurosyphilis und opportunistische Infektionen bei Immunsuppressionszuständen finden hierbei besondere Berücksichtigung. Der zweite Teil dieses Kapitels behandelt akute und chronische Virusinfektionen des ZNS sowie in einem gesonderten Abschnitt die HIVInfektion und HIV-assoziierte Krankheitsbilder sowie Parasitosen und Pilzinfektionen, die in Industrieländern seit Einführung der HAART bei HIV zwar eher seltener, aber mit zunehmender Globalisierung auch in unseren Breiten immer noch anzutreffen sind.

Differentiation of pyogenic and fungal brain abscesses with susceptibility-weighted MR sequences

INTRODUCTION

Conventional magnetic resonance imaging (MRI) techniques are insufficient to determine the causative agent of brain abscesses. We investigated: (1) the value of susceptibility-weighted MR sequences (SWMRS) in the differentiation of fungal and pyogenic brain abscesses; and (2) the effect of different SWMRS (susceptibility-weighted imaging (SWI) versus venous blood oxygen level dependent (VenoBOLD)) for the detection of specific imaging characteristics of pyogenic brain abscesses.

METHODS

We studied six patients with fungal and ten patients with pyogenic brain abscesses. Imaging characteristics on conventional MRI, diffusion-weighted imaging (DWI) and SWMRS were recorded in all abscesses. All lesions were assessed for the presence of a "dual-rim sign" on SWMRS.

RESULTS

Homogenously hyperintense lesions on DWI were present in 60 % of patients with pyogenic abscesses, whereas none of the patients with fungal abscesses showed such lesions. On SWMRS, 90 % of patients with pyogenic abscesses and 60 % of patients with fungal abscesses had only lesions with a low-signal-intensity rim. On SWI, the dual-rim sign was apparent in all pyogenic abscesses. None of the fungal abscesses on SWI (P = 0.005) or any of the pyogenic abscesses on VenoBOLD (P = 0.005) were positive for a dual-rim sign.

CONCLUSIONS

In fungal abscesses, the dual-rim sign is not present but a prominent peripheral rim or central susceptibility effects on SWI will be seen. The appearance of pyogenic abscesses on SWMRS depends on the used sequence, with the dual-rim sign a specific feature of pyogenic brain abscesses on SWI.

Magnetic resonance imaging in fungal infections of the brain

An invasive fungal infection is a rare disease that can occur in otherwise healthy individuals. Fungi themselves are universal, and they are overall harmless organisms that cause at most a self-limiting disease in the general population. Immunocompromised individuals, whether iatrogenically, genetically, or acquired, present a group who are especially susceptible to a life-threatening disease from a normally innocuous pathogen. Fungi are normally inhaled and are cleared by pulmonary defense mechanisms in immunocompetent hosts. Invasion begins when these mechanisms fail in depressed immunity. Through bypassing of the pulmonary immune system, fungi can spread hematogenously. Fungal infections of the central nervous system are the most common extrapulmonary manifestation after fungal inhalation. Other risk factors of fungemia include prolonged indwelling catheters, maxillofacial infections, uncontrolled diabetes mellitus, systemic antibiotics, implanted neurosurgical devices, and intravenous drug abuse. Thus, other than direct inoculation via surgical complications or open trauma, central nervous system fungal infections are almost never primary.

Fungal central nervous system infections: prevalence and diagnosis

Fungal infections of the central nervous system (CNS) are rare but they pose a significant challenge. Their prevalence spans a wide array of hosts including immunosuppressed and immunocompetent individuals, patients undergoing neurosurgical procedures and those carrying implantable CNS devices. Cryptococcus neoformans and Aspergillus spp. remain the most common pathogens. Magnetic resonance imaging can help localize the lesions, but diagnosis is challenging since invasive procedures may be needed for the retrieval of tissue, especially in cases of fungal abscesses. Antigen and antibody tests are available and approved for use in the cerebrospinal fluid (CSF). PCR-based techniques are promising but they are not validated for use in the CSF. This review provides an overview on the differential diagnosis of the fungal CNS disease based on the host and the clinical syndrome and suggests the optimal use of diagnostic techniques. It also summarizes the emergence of Cryptococcus gatti and an unanticipated outbreak caused by Exserohilum rostratum.

Madurella mycetomatis as an agent of brain abscess: case report and review of literature

Fungal cerebral abscesses are rare and usually seen in immunocompromised individuals. We report a case and review published literature of Madurella mycetomatis as an agent of cerebral abscess. We found contiguous head and neck infections to be the principal cause of cerebral maduromycosis caused by M. mycetomatis. Early recognition of Madurella spp. as the causative agent is essential to avoid cerebral spread.

Opportunistic Fonsecaea pedrosoi brain abscess in a patient with non-cirrhotic portal fibrosis-induced hypersplenism--a novel association

Non-cirrhotic portal fibrosis, a common cause of splenomegaly in tropical countries, can lead to hypersplenism and pancytopenia. Hypersplenism in this setting has not been associated with opportunistic infections. We describe a patient with hypersplenism secondary to non-cirrhotic portal fibrosis who developed a Fonsecaea pedrosoi brain abscess and succumbed to the illness despite aggressive management.

In vitro interactions of amantadine hydrochloride, R-(-)-deprenyl hydrochloride and valproic acid sodium salt with antifungal agents against filamentous fungal species causing central nervous system infection

The mortality rates of fungal infections that affect the central nervous system are high in consequence of the absence of effective antifungal drugs with good penetration across the blood-brain barrier and the blood-cerebrospinal fluid barrier. In the present work in vitro antifungal activities of three good penetrating non-antifungal drugs (amantadine hydrochloride, R-(-)-deprenyl hydrochloride, valproic acid sodium salt) and their combinations with three antifungal agents (amphotericin B, itraconazole, terbinafine) were tested with broth microdilution method against eight fungal isolates belonging to Zygomycetes (Lichtheimia corymbifera, Rhizomucor miehei, Rhizopus microsporus var. rhizopodiformis, Saksenaeavasiformis) and Aspergillus genus (A. flavus, A. fumigatus, A. nidulans, A. terreus). These are known to be possible agents of central nervous fungal infections (CNFI). When used alone, the investigated nonantifungal drugs exerted slight antifungal effects. In their combinations with antifungal agents they acted antagonistically, additively and synergistically against zygomyceteous isolates. Primarily antagonistic interactions were revealed between the investigated drugs in case of Aspergilli, but additive and synergistic interactions were also observed. The additive and synergistic combinations allowed the usage of reduced concentrations of antifungal agents to inhibit the fungal growth in our study. These combinations would be a basis of an effective, less toxic therapy for treatment of CNFI.

Real-time in vivo imaging of fungal migration to the central nervous system

Recent technical advances have afforded valuable new insights into the pathogenesis of fungal infections in the central nervous system (CNS), which continue to cause devastating complications, particularly in immunocompromised individuals. To cause CNS mycosis, organisms such as Cryptococcus neoformans become blood borne and progress through a series of pathogenic checkpoints that culminate in fungal replication in the brain. Critical steps include fungal arrest in the vasculature of the brain, interaction and signalling of the fungal and endothelial cells leading to transmigration with subsequent parenchymal invasion and fungal replication in the CNS. Previous studies that made use of in vitro and ex vivo approaches contributed greatly to our understanding of brain invasion by fungi. However, the knowledge gained from previous studies relied on in vitro models that did not account for vascular haemodynamics. For this reason, more refined approaches that model blood flow and vascular anatomy are required, andultimately studying fungal invasion and dissemination in vivo. Indeed, in vivo imaging (also known as intravital imaging) has emerged as a valuable technique to probe host-pathogen interactions. In this review, with a focus on C. neoformans, we will provide an overview of the applications of the prior techniques and recent advances, their strengths and limitations in characterizing the migration of fungi into the brain, and unanswered questions that may provide new directions for research.

Complement Attack against Aspergillus and Corresponding Evasion Mechanisms

Invasive aspergillosis shows a high mortality rate particularly in immunocompromised patients. Perpetually increasing numbers of affected patients highlight the importance of a clearer understanding of interactions between innate immunity and fungi. Innate immunity is considered to be the most significant host defence against invasive fungal infections. Complement represents a crucial part of this first line defence and comprises direct effects against invading pathogens as well as bridging functions to other parts of the immune network. However, despite the potency of complement to attack foreign pathogens, the prevalence of invasive fungal infections is increasing. Two possible reasons may explain that phenomenon: First, complement activation might be insufficient for an effective antifungal defence in risk patients (due to, e.g., low complement levels, poor recognition of fungal surface, or missing interplay with other immune elements in immunocompromised patients). On the other hand, fungi may have developed evasion strategies to avoid recognition and/or eradication by complement. In this review, we summarize the most important interactions between Aspergillus and the complement system. We describe the various ways of complement activation by Aspergillus and the antifungal effects of the system, and also show proven and probable mechanisms of Aspergillus for complement evasion.

Molecular mechanisms of cryptococcal meningitis

Fungal meningitis is a serious disease caused by a fungal infection of the central nervous system (CNS) mostly in individuals with immune system deficiencies. Fungal meningitis is often fatal without proper treatment, and the mortality rate remains unacceptably high even with antifungal drug interventions. Currently, cryptococcal meningitis is the most common fungal meningitis in HIV-1/AIDS, and its disease mechanism has been extensively studied. The key steps for fungi to infect brain and cause meningitis after establishment of local infection are the dissemination of fungal cells to the bloodstream and invasion through the blood brain barrier to reach the CNS. In this review, we use cryptococcal CNS infection as an example to describe the current molecular understanding of fungal meningitis, including the establishment of the infection, dissemination, and brain invasion. Host and microbial factors that contribute to these infection steps are also discussed.

Infektionen

Trotz Weiterentwicklung moderner Antibiotika in den letzten Jahren sind die Letalitätszahlen der bakteriellen (eitrigen) Meningitis weiterhin hoch; Überlebende haben häufig neurologische Residuen. Die ungünstigen klinischen Verläufe der bakteriellen Meningitis sind meist Folge intrakranieller Komplikationen, wie z. B. eines generalisierten Hirnödems, einer zerebrovaskulären arteriellen oder venösen Beteiligung oder eines Hydrozephalus.

Infektionskrankheiten

Virale Infektionen zählen immer noch weltweit, besonders in den Entwicklungsländern, zu den häufigsten Todesursachen. Durch internationale systematische Impfkampagnen der WHO ist die Welt Pocken-frei geworden. Die Inzidenz der Infektionen, die durch eine Immunprophylaxe verhindert werden können, wurde drastisch gesenkt (Poliomyelitis, Tollwut). In den 1980er Jahren trat eine neue Tierseuche beim Rind auf, die bovine spongyforme Enzephalopathie (BSE), die mit der neuen Variante der Creutzfeldt-Jakob-Krankheit (vCJK) in Zusammenhang steht (Nahrungskette). Im selben Zeitraum begann die explosionsartige weltweite Verbreitung eines neuen Retrovirus, des HIV. Trotz intensiver Aufklärungskampagnen und neuen therapeutischen Möglichkeiten (HAART, hoch aktive antiretrovirale Therapie) ist es bis zur Jahrtausendwende nicht gelungen, die weitere Ausbreitung der HIV-Infektion zu verhindern. Seit 2007 ist eine allmähliche Eindämmung der Infektion zu erkennen, die Neuinfektionen sind weltweit rückläufig. Durch den breiteren Einsatz der HAART sind Lebensqualität und Lebenserwartung enorm gestiegen, die Sterberate der AIDS-Infizierten ist seit 2005 um mehr als 50 % zurückgegangen.

Central nervous system infectious complications early after liver transplantation

Infectious complications contribute to significant patient morbidity and mortality in orthotopic liver transplant (OLT) recipients. Early central nervous system (CNS) involvement (within the first month after OLT) by infectious disease is essentially set off by aggressive surgical procedures, severe morbid conditions of the pretransplant period, initial graft dysfunction, permanence of intravascular catheters, and prolonged mechanical ventilation. The type and severity of CNS infection may be determined by many factors, such as posttransplant adverse events; prolonged or repeated surgery with massive intraoperative transfusions, net state of immunosuppression, recurrence of infections by immunomodulating viruses, and retransplantation. Bacteria, viruses, and fungi can spread to the CNS just as they affect the abdomen, blood stream, respiratory tract, urine, drainages, etc. Because immunosuppressive drugs may modify the clinical presentation of CNS infections, it is very important to maintain vigilance and attend to minor neurologic symptoms. Special attention should therefore be given to cerebral investigation in patients with prolonged pulmonary contamination, unresponsive fever, and heavy corticosteroid therapy, primarily when they became disoriented, develop seizures, or exhibit focal neurologic signs. Clinical response to medical therapy may sometimes be poor because of chronic encapsulation of the pathogen, development of resistance, and/or catastrophic hemorrhagic complications.

Fungal infections of the central nervous system in HIV-negative patients: experience from a tertiary referral center of South India

Objective:

To describe the clinical, radiological, and cerebrovascular fluid (CSF) findings and the outcome of microbiologically or histopathologically proven fungal infections of the central nervous system (CNS) in HIV-negative patients.

Methodology and Results:

We identified definite cases of CNS mycosis by screening the medical records of our institute for the period 2000–2008. The clinical and imaging details and the outcome were abstracted from the medical records and entered in a structured proforma. There were 12 patients with CNS mycosis (i.e., 2.7% of all CNS infections treated in this hospital); six (50%) had cryptococcal infection, three (25%) had mucormycosis, and two had unclassified fungal infection. Four (33%) of them had diabetes as a predisposing factor. The common presentations were meningoencephalitis (58%) and polycranial neuritis (41%). Magnetic resonance imaging revealed hydrocephalus in 41% and meningeal enhancement in 25%, as well as some unusual findings such as subdural hematoma in the bulbocervical region, carpeting lesion of the base of the skull, and enhancing lesion in the cerebellopontine angle. The CSF showed pleocytosis (66%), hypoglycorrhachia (83%), and elevated protein levels (100%). The diagnosis was confirmed by meningocortical biopsy (in three cases), paranasal sinus biopsy (in four cases), CSF culture (in three cases), India ink preparation (in four cases), or by cryptococcal polysaccharide antigen test (in three cases). Out of the ten patients for whom follow-up details were available, six patients recovered with antifungal medications (amphotericin B, 1 mg/kg/day for the minimum period of 6 weeks) and/or surgical treatment. Four patients expired (only one of them had received antifungal therapy).

Conclusions:

Most patients with CNS mycosis recover with appropriate therapy, but the diagnosis and management of these rare infections remains a challenge to clinicians.

Successful treatment of a case with rhino-orbital-cerebral mucormycosis by the combination of neurosurgical intervention and the sequential use of amphotericin B and posaconazole

Rhino-orbital-cerebral (ROC) mucormycosis is an uncommon, acute and aggressive fungal infection. It remains a challenging problem to clinicians despite aggressive debridement surgery and antifungal therapy. The authors describe a case of ROC mucormycosis with pericranial abscess occurring in a female patient with uncontrolled diabetes mellitus. The infection initially developed in the right-sided nasal sinus and later progressed through the paranasal sinuses with the invasion of the peri-orbital and frontotemporal region, due to the delayed diagnosis and treatment. Numerous non-septate hyphae of the zygomycetes were identified by a punch biopsy from the nasal cavity and by an open biopsy of the involved dura. The patient was treated successfully with extensive debridement of her necrotic skull and surrounding tissues, drainage of her pericranial abscess and antifungal therapy, including intravenous amphotericin B for 61 days and oral posaconazole for the following 26 days. She returned to a normal life and has had no recurrence since the end of her treatment 15 months ago.