First report of a case of meningitis caused by Cryptococcus adeliensis in a patient with acute myeloid leukemia

Genomic Characterization of the Titan-like Cell Producing Naganishia tulchinskyi, the First Novel Eukaryote Isolated from the International Space Station

Multiple strains of a novel yeast belonging to genus Naganishia were isolated from environmental surfaces aboard the International Space Station (ISS). These strains exhibited a phenotype similar to Titan cell (~10 µm diameter) morphology when grown under a combination of simulated microgravity and 5% CO₂ conditions. Confocal, scanning, and transmission electron microscopy revealed distinct morphological differences between the microgravity-grown cells and the standard Earth gravity-grown cells, including larger cells and thicker cell walls, altered intracellular morphology, modifications to extracellular fimbriae, budding, and the shedding of bud scars. Phylogenetic analyses via multi-locus sequence typing indicated that these ISS strains represented a single species in the genus Naganishia and were clustered with Naganishia diffluens. The name Naganishia tulchinskyi is proposed to accommodate these strains, with IF6SW-B1^T as the holotype. The gene ontologies were assigned to the cell morphogenesis, microtubule-based response, and response to UV light, suggesting a variety of phenotypes that are well suited to respond to microgravity and radiation. Genomic analyses also indicated that the extracellular region, outer membrane, and cell wall were among the highest cellular component results, thus implying a set of genes associated with Titan-like cell plasticity. Finally, the highest molecular function matches included cytoskeletal motor activity, microtubule motor activity, and nuclear export signal receptor activity.

A global view on fungal infections in humans and animals: opportunistic infections and microsporidioses

After cardiovascular diseases, infectious diseases are the second most common cause of death worldwide. Although these infections are caused mainly by viruses or bacteria, a systematically growing prevalence of human and animal opportunistic fungal infections is noticeable worldwide. More attention is being paid to this problem, especially due to the growing frequency of recalcitrant and recurrent mycoses. The latter are classically divided into superficial, which are the most common type, subcutaneous, and systemic. This work discusses opportunistic fungal pathogens without proven horizontal transmission between different animal species including humans and microsporidia as spore-forming unicellular parasites related to fungi; however, with a yet undetermined taxonomic position. The review also mentions aetiological agents, risk factors, epidemiology, geographical distribution, and finally symptoms characteristic for individual disease entities. This paper provides insight into fungal infections from a global perspective and simultaneously draws attention to emerging pathogens, whose prevalence is continuously increasing. Finally, this work also takes into consideration the correct nomenclature of fungal disease entities and the importance of secondary metabolites in the pathogenesis of fungal infections.

Sequential infection of Epstein-Barr virus and cryptococcal encephalitis after umbilical cord blood transplantation in a child with X-linked adrenoleukodystrophy

Dual infection with two pathogens can be found in few cases of encephalitis. Cases of sequential infection with EBV and cryptococcal encephalitis in post-transplant patients are rare. We describe a 5-year-old boy with X-linked adrenoleukodystrophy who presented sequential infection with EBV and cryptococcal encephalitis after umbilical cord blood transplant. The patient showed fever, vomiting and emotional agitation with EBV DNA detected in CSF on day 100. The child underwent 3 doses of intravenous rituximab with a good response. However, the child presented with right facial paralysis, headache, and fever on day 130 after 2 weeks of clinical stability. Brain MRI demonstrated chronic granuloma formed with ring enhancement. FilmArray ME PCR confirmed the existence of Cryptococcus neoformans/gattii in the CSF. The child underwent sequential treatment with amphotericin liposome B and flucytosine. Maintenance treatment with fluconazole was administered for 1 year. Facial paralysis was on longer present on day 260. Cryptococcus neoformans/gattii was not detected on day 310. The biochemistry and cell count of the CSF were completely normal on day 520. Follow-up 2.5 years after presentation, brain MRI changes showed near complete resolution of the lesions. The child survived for 3 years to the last following-up. Invasive cryptococcal encephalitis is rare and life-threatening complication of transplantation. It is important to recognize dual infections, and perform treatment quickly to improve the prognosis of encephalitis after transplantation.

Titan cell formation is unique to Cryptococcus species complex

Members of the Cryptococcus species complex stand out by unique virulence factors that allowed evolutionary transition to pathogenesis. Among the factors contributing to cryptococcosis is a morphological transformation into giant (Titan) cells. It remains unclear whether species outside of the C. neoformans/C. gattii species complex are capable of titanization. We utilized two recently developed protocols that allow obtaining Titan cells in vitro to test if titanization occurs in non-C. neoformans/C. gattii species. We find that none of the tested strains, representing 10 species of basidiomycetous yeasts and the ascomycetous yeast Saccharomyces cerevisiae, undergo significant titanization under conditions that promote robust Titan cell formation in C. neoformans/C. gattii species complex. C. terreus formed occasional enlarged cells through a mechanism potentially similar to that of titanization. Our findings suggest that titanization is a rare phenomenon among basidiomycetous yeasts that occurs mostly in members of the C. neoformans/C. gattii species complex.

Infections due to Rare Cryptococcus Species. A Literature Review

Infections due to rare Cryptococcus species (other than C. neoformans species complex, C. gattii species complex, C. albidus or C. laurentii) are barely reported. The aim of this work is to present a comprehensive literature review of all the papers describing infections due to these species referenced in the main databases (PubMed/MEDLINE, ScienceDirect, Scopus, and Google Scholar). Clinical and epidemiological data together with laboratory findings (identification and antifungal susceptibility) of each isolate were analyzed. Fifty-eight cryptococosis due to rare species were described in 46 papers between 1934-2018. These reports included 16 rare Cryptococcus spp. that were generally associated with nervous system infections and fungemias. Some species are non-capsulated and are not able to grow at 37 °C. Few species were identified by commercially available methods, making internal transcriber spacer (ITS) and D1/D2 regions sequencing mandatory. The most potent antifungal was amphotericin B (although some species showed high MIC values). The studied strains showed high MICs values to 5-fluorocytosine (all >64 µg/mL), echinocandins (all >8 µg/mL), and fluconazole (>80% of the MICs >4 µg/mL). Due to the scarcity of the data and the absence of guidelines for the treatment of these infections, this review could be informative and could help in the diagnosis and treatment of these infections.

Cryptococcus Species Other Than Cryptococcus neoformans and Cryptococcus gattii: Are They Clinically Significant?

Background

Cryptococcus spp is a major cause of opportunistic infections in immunocompromised patients, primarily due to Cryptococcus neoformans and Cryptococcus gattii. There are occasional reports of other Cryptococcus species causing invasive human disease. However, their epidemiology and clinical significance are not fully defined. We sought to describe cases with cultures positive for Cryptococcus species other than C neoformans and C gattii.

Methods

A retrospective descriptive analysis of clinical and laboratory data of patients with cultures growing Cryptococcus species other than C neoformans and C gattii from November 2011 to February 2019 was performed. Three Mayo Clinic sites in Arizona, Florida, and Minnesota were included.

Results

From 176 cases with a culture growing Cryptococcus spp, 54 patients (30%) had a culture for Cryptococcus other than C neoformans and C gattii in the study time frame. The most common species were Cryptococcus magnus, Cryptococcus laurentii, and Cryptococcus ater. The organisms were isolated and identified in culture of bronchoalveolar lavage (11), skin (11), urine (7), oral (4), sinus (3), intraoperative soft tissue (3), sputum (2), synovial fluid (2), cerebrospinal fluid (2), and intravenous catheter (2), among others (7).

Only 8 (15%) cases were considered to be potentially pathogenic, with 1 case of invasive disease. Antifungal treatment was fluconazole, itraconazole, and griseofulvin, for a mean systemic antifungal duration of 42 days.

Conclusions

This large series of patients with Cryptococcus spp other than C neoformans and C gattii suggests that these species rarely cause clinically significant infection in humans. Only 1 case of invasive disease was found.

Cryptococcosis in Hematopoietic Stem Cell Transplant Recipients: A Rare Presentation Warranting Recognition

Cryptococcosis, a life-threatening mycosis caused mainly by Cryptococcus neoformans, appears to be distinctly rare in hematopoietic stem cell transplant (HSCT) recipients. When it occurs, this fungal infection is a major limitation for a successful transplant. This review comprehensively analyses 24 cases, reported in the literature, of patients with haematological malignancies including leukemias, multiple myeloma, and lymphomas, as indication for HSCT, who presented with cryptococcosis after transplantation. Of the 24 cases, 11 each occurred in patients receiving allogeneic and autologous stem cell transplants, from bone marrow, peripheral blood, and umbilical cord blood. HSCT recipients were slightly more often male, and the age of the patients ranged from 12 to 74 years. Antifungal prophylaxis was reported in most cases. Clinical manifestations of cryptococcal disease included more frequently central nervous system involvement followed by fungaemia, disseminated infection, pulmonary cryptococcosis, cerebellitis, and diarrhea. Diagnosis differed depending on the clinical presentation but habitually included cryptococcal antigen assay, India ink, and culture. Notably, not only C. neoformans but also C. albidus, C. terreus, C. laurentii, and C. adeliensis were identified as the causal species, the last two including strains resistant to fluconazole. Amphotericin B, alone or in combination, was the most common antifungal drug used for the treatment of cryptococcosis in HSCT recipients. Due to the small number of cases, it was not possible to establish if mortality rate, which was the same as survival rate, depends on the effect of the immunosuppressive regimen, the site of cryptococcal infection, and/or the antifungal therapy used to control the mycosis. Although uncommon, the recognition of cryptococcal disease in stem cell transplant is essential for a timely and adequate treatment, improved prognosis, reduced morbidity and mortality, and successful transplantation.

Cryptococcal meningitis following umbilical cord blood transplantation, association between the occurrence of cryptococcal infection and tacrolimus discontinuation among allogeneic hematopoietic stem cell recipients

Few cases of cryptococcal infection following umbilical cord blood transplantation (UCBT) have been reported. We report a case, where cryptococcal infection occurred soon after rapidly reducing the dose of tacrolimus in a UCBT recipient who received micafungin prophylaxis during the early phase of transplantation. The etiology of cryptococcal infection following allogeneic hematopoietic stem cell transplantation (allo-HSCT), including UCBT, might be associated with rapid dose-reduction of calcineurin inhibitors, such as tacrolimus during early phase of allo-HSCT. To our knowledge, this is the first English-language report to describe in detail a case of cryptococcal meningitis with fungemia during early phase of UCBT.

Atypical Morphology and Disparate Speciation in a Case of Feline Cryptococcosis

A 6-year-old, spayed female cat was presented with acute respiratory signs and pleural effusion. Computed tomography scan revealed a large, lobulated mass effect in the ventral right hemithorax with concurrent sternal lymphadenopathy. A cytologic sample of the mass contained pyogranulomatous inflammation, necrotic material, and abundant yeast structures that lacked a distinct capsule and demonstrated rare pseudohyphal forms. Fungal culture and biochemical testing identified the yeast as Cryptococcus albidus, with susceptibility to all antifungal agents tested. However, subsequent 18S PCR identified 99% homology with a strain of Cryptococcus neoformans and only 92% homology with C. albidus. The patient responded well to fluconazole therapy unlike the only known previous report of C. albidus in a cat. The unusual cytologic morphology in this case underscores the need for ancillary testing apart from microscopy for fungal identification. Though C. albidus should be considered as a potential feline pathogen, confirmation with PCR is recommended when such rare non-neoformans species are encountered.

Yeasts

Yeasts are unicellular organisms that reproduce mostly by budding and less often by fission. Most medically important yeasts originate from Ascomycota or Basidiomycota. Here, we review taxonomy, epidemiology, disease spectrum, antifungal drug susceptibility patterns of medically important yeast, laboratory diagnosis, and diagnostic strategies.

Isolation and molecular characterization of Cryptococcus species isolated from pigeon nests and Eucalyptus trees

Background and Purpose:

Cryptococcus species are pathogenic and non-pathogenic basidiomycete yeasts that are found widely in the environment. Based on phenotypic methods, this genus has many species; however, its taxonomy is presently being re-evaluated by modern techniques. The Cryptococcus species complex includes two sibling taxa of Cryptococcus neoformans and Cryptococcus gattii. We aimed to investigate the possible distribution of Cryptococcus species in pigeon nests and Eucalyptus trees in Ilam, Iran, using molecular techniques.

Materials and Methods:

Two hundred and seventy-four specimens were collected from pigeon nests and Eucalyptus trees during 2016-2017. All the specimens were sub-cultured on Sabouraud Glucose Agar with chloramphenicol and bird seed agar. For molecular identification, the ITS15.8SITS2 rDNA region was amplified using the first and fourth internal transcribed spacer (ITS1 and ITS4, respectively) primers. The purified products were applied for cycle sequencing reactions in forward direction with ITS1 primer. The obtained results were analyzed with Chromas 2.3.

Results:

Thirty-three out of 186 cultures (17.7%) and 11 out of 88 cultures (12.5%) were positive among pigeon nest and Eucalyptus tree specimens, respectively. Cryptococcus albidus (17.2%), C. albidus var. kuetzingii (3.4%), C. adeliensis (3.4%), C. uzbekistanensis (3.4%), and C. neoformans var. grubii (3.4%) were isolated from pigeon nests, and Cryptococcusadeliensis (25%) was the only Cryptococcus species isolated from Eucalyptus trees.

Conclusion:

The presence of pigeons and Eucalyptus trees in the vicinity of some particular places such as rest homes and hospitals should be considered as a risk factor for the immunocompromised population.

Cryptococcal meningitis post autologous stem cell transplantation

Disseminated Cryptococcus disease occurs in patients with defective T-cell immunity. Cryptococcal meningitis following autologous stem cell transplant (SCT) has been described previously in only 1 patient, 4 months post SCT and while off antifungal prophylaxis. We present a unique case of Cryptococcus meningitis pre-engraftment after autologous SCT, while the patient was receiving fluconazole prophylaxis. A 41-year-old man with non-Hodgkin's lymphoma underwent autologous SCT. Post-transplant prophylaxis consisted of fluconazole 400 mg daily, levofloxacin 500 mg daily, and acyclovir 800 mg twice daily. On day 9 post transplant, he developed fever and headache. Peripheral white blood cell count (WBC) was 700/μL. Magnetic resonance imaging of the brain showed lesions consistent with meningoencephalitis. Cerebrospinal fluid (CSF) analysis revealed a WBC of 39 with 77% lymphocytes, protein 63, glucose 38, CSF pressure 20.5 cmH2 O, and a positive cryptococcal antigen. CSF culture confirmed Cryptococcus neoformans. The patient was treated with liposomal amphotericin B 5 mg/kg intravenously daily, and flucytosine 37.5 mg/kg orally every 6 h. He was switched to fluconazole 400 mg daily after 3 weeks of amphotericin therapy, with sterilization of the CSF with negative CSFCryptococcus antigen and negative CSF culture. Review of the literature revealed 9 cases of cryptococcal disease in recipients of SCT. Median time of onset was 64 days post transplant. Only 3 meningitis cases were described; 2 of them after allogeneic SCT. Fungal prophylaxis with fluconazole post autologous SCT is recommended at least through engraftment, and for up to 100 days in high-risk patients. A high index of suspicion is needed to diagnose and treat opportunistic infections, especially in the face of immunosuppression and despite adequate prophylaxis. Infection is usually fatal without treatment, thus prompt diagnosis and therapy might be life saving.

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Meningitis caused by Filobasidium uniguttulatum: case report and overview of the literature

Cryptococcal meningitis is mainly caused by Cryptococcus neoformans and Cryptococcus gattii, but occasionally other Cryptococcus species and phylogenetically related species are involved. Herein, we present a case of cryptococcal meningitis from China, which was caused by an azole and flucytosine resistant Filobasidium uniguttulatum. In addition, we present an overview of the literature of meningitis caused by Cryptococcus species other than C. neoformans and C. gattii. Eight cases were related to infections of the central nervous system. Leukaemia and cancer were important risk factors in HIV-negative patients. Molecular identification and susceptibility testing are important for proper management of patients because the species involved may differ in susceptibility to antifungal drugs.

Cryptococcus gattii: an emerging fungal pathogen infecting humans and animals

Infectious fungi are among a broad group of microbial pathogens that has and continues to emerge concomitantly due to the global AIDS pandemic as well as an overall increase of patients with compromised immune systems. In addition, many pathogens have been emerging and re-emerging, causing disease in both individuals who have an identifiable immune defect and those who do not. The fungal pathogen Cryptococcus gattii can infect individuals with and without an identifiable immune defect, with a broad geographic range including both endemic areas and emerging outbreak regions. Infections in patients and animals can be severe and often fatal if untreated. We review the molecular epidemiology, population structure, clinical manifestations, and ecological niche of this emerging pathogen.

The effect of fungicides on yeast communities associated with grape berries

The influence of three commonly used fungicides (iprodione, pyrimethanil and fludioxonil plus cyprodinil) on the density and diversity of yeast populations present on grape berries was evaluated. At the time of harvest, the fungicide residues on grapes were below the maximum permitted levels. In general, larger yeast counts were found on the treated grapes than on the control samples. Among 23 species identified, Cryptococcus magnus, Rhodotorula glutinis and Sporidiobolus pararoseus dominated on sound grape berries. The results showed that the tested fungicides had only a minor impact on the composition of grape berry communities in comparison with the effect of weather conditions and the mode of grape berry sampling. Halo assays using filter discs loaded with fungicides were used as in vitro tests of the sensitivity of grape berry isolates. The fungicide containing pyrimethanil suppressed the growth of all basidiomycetous yeast species, while the sporadically occurring fermentative yeasts were unaffected. Fungicides with fludioxonil plus cyprodinil and iprodione as active substances showed specificity for certain species. Our results suggest that after the safety interval, the presence of fungicides has a minor impact on the composition of grape berry communities, although at the time of fungicide applications, the yeast species composition changes.

Phylogeny and phenotypic characterization of pathogenic Cryptococcus species and closely related saprobic taxa in the Tremellales

The basidiomycetous yeasts Cryptococcus neoformans and Cryptococcus gattii are closely related sibling species that cause respiratory and neurological disease in humans and animals. Within these two recognized species, phylogenetic analysis reveals at least six cryptic species defined as molecular types (VNI/II/B, VNIV, VGI, VGII, VGIII, and VGIV) that comprise the pathogenic Cryptococcus species complex. These pathogenic species are clustered in the Filobasidiella clade within the order Tremellales. Previous studies have shown that the Filobasidiella clade also includes several saprobic fungi isolated from insect frass, but information evaluating the relatedness of the saprobes and pathogens within this cluster is limited. Here, the phylogeny encompassing a subset of species in the Tremellales lineage that clusters closely with the pathogenic Cryptococcus species complex was resolved by employing a multilocus sequencing approach for phylogenetic analysis. Six highly conserved genomic loci from 15 related basidiomycete species were sequenced, and the alignments from the concatenated gene sequences were evaluated with different tree-building criteria. Furthermore, these 15 species were subjected to virulence and phenotype assays to evaluate their pathogenic potential. These studies revealed that Cryptococcus amylolentus and Tsuchiyaea wingfieldii, two nonpathogenic sibling species, are the taxa most closely related to the pathogens C. neoformans and C. gattii and together with Filobasidiella depauperata form a Cryptococcus sensu stricto group. Five other saprobic yeast species form the Kwoniella clade, which appears to be a part of a more distantly related sensu lato group. This study establishes a foundation for future comparative genomic approaches that will provide insight into the structure, function, and evolution of the mating type locus, the transitions in modes of sexual reproduction, and the emergence of human pathogenic species from related or ancestral saprobic species.

Subcutaneous cryptococcosis due to Cryptococcus diffluens in a patient with sporotrichoid lesions case report, features of the case isolate and in vitro antifungal susceptibilities

Environmental fungi, in particular primary pathogens and Cryptococcus spp. can be responsible for skin lesions mimicking sporotrichosis. In this paper, we report a case of subcutaneous cryptococcosis in an apparently healthy, young male patient due to a non-C. neoformans Cryptococcus species, C. diffluens. The isolate showed in vitro phenotypic switching that may affect virulence and host inflammatory and immune responses, and in vitro resistance to amphotericin B and 5-flucytosin. This species shares several phenotypic traits with C. neoformans, and, therefore, decisive diagnosis should be based on biopsy and culturing results followed by molecular identification.

Pneumonia and pleural effusion due to Cryptococcus laurentii in a clinically proven case of AIDS

Non-neoformans cryptococci were previously considered to be saprophytes and nonpathogenic to humans. Cryptococcus laurentii is frequently used as a biological means to control fruit rot. Interestingly, C laurentii has recently been reported to be a rare cause of infection in humans. The authors report a case of pulmonary cryptococcosis caused by C laurentii in a diabetic AIDS patient who was on antituberculosis and antiretroviral treatments. The sputum smear revealed capsulated yeast cells that were identified as C laurentii. Repeated pleural fluid culture revealed growth of C laurentii. Both respiratory samples were negative for acid-fast bacilli. Moraxella catarrhalis and Klebsiella pneumoniae were also found in the sputum, but not in the pleural fluid. The patient had a good response to oral fluconazole therapy at 600 mg/day for five weeks and was then discharged. The present article is the first to report on the rare pulmonary involvement of C laurentii in the Indian HIV population. These unusual forms of cryptococci create a diagnostic predicament in the rapid diagnosis of pulmonary cryptococcosis. A high degree of suspicion and improvement of techniques for culture and identification will contribute to the early diagnosis and treatment of unusual fungal infections.

Ultrastructural and chemotaxonomic analysis of a xylanolytic strain of Cryptococcus adeliensis isolated from sheep droppings in Spain

Cryptococcus adeliensis was initially described as a psycrophilic species containing a single strain CBS 8351(T) isolated from decayed algae in Terre Adelie (Antartida). Later, a second strain of this species was isolated from an immunosuppressed patient affected by leukaemia in Germany and recently several strains from this species have been found in human patients and pigeon droppings of the same country. In this study, we isolated from sheep droppings in Spain a xylanolytic strain named LEVX01 that was phenotypically related to the strain CBS 8351(T) and showed a 100% similarity in the D1/D2 domain and 5.8S-ITS region sequences with respect to the remaining described strains of C. adeliensis. These findings suggest that this species has a wide geographical distribution and that the animal faeces are a common habitat for C. adeliensis. The chemotaxonomic analyses showed the absence of detectable amounts of xylose in the cell walls of the strains LEVX01 and CBS8351(T) in contrast to other Cryptococcus species. Interestingly, the ultrastructural study showed the presence of fimbriae in these two strains that could be involved in the attachment to the host cells and, as occurs in Candida albicans, they could also be a pathogenicity factor for the man.

Identification of medically important yeast species by sequence analysis of the internal transcribed spacer regions

Infections caused by yeasts have increased in previous decades due primarily to the increasing population of immunocompromised patients. In addition, infections caused by less common species such as Pichia, Rhodotorula, Trichosporon, and Saccharomyces spp. have been widely reported. This study extensively evaluated the feasibility of sequence analysis of the rRNA gene internal transcribed spacer (ITS) regions for the identification of yeasts of clinical relevance. Both the ITS1 and ITS2 regions of 373 strains (86 species), including 299 reference strains and 74 clinical isolates, were amplified by PCR and sequenced. The sequences were compared to reference data available at the GenBank database by using BLAST (basic local alignment search tool) to determine if species identification was possible by ITS sequencing. Since the GenBank database currently lacks ITS sequence entries for some yeasts, the ITS sequences of type (or reference) strains of 15 species were submitted to GenBank to facilitate identification of these species. Strains producing discrepant identifications between the conventional methods and ITS sequence analysis were further analyzed by sequencing of the D1-D2 domain of the large-subunit rRNA gene for species clarification. The rates of correct identification by ITS1 and ITS2 sequence analysis were 96.8% (361/373) and 99.7% (372/373), respectively. Of the 373 strains tested, only 1 strain (Rhodotorula glutinis BCRC 20576) could not be identified by ITS2 sequence analysis. In conclusion, identification of medically important yeasts by ITS sequencing, especially using the ITS2 region, is reliable and can be used as an accurate alternative to conventional identification methods.

Management of intracranial fungal infections in patients with haematological malignancies

The incidence of, and mortality associated with, invasive fungal infections remains far higher than hoped. As a consequence of the overall increase in the incidence of such infections over time, the incidence of central nervous system (CNS) fungal infections is also increasing and, despite improvements in diagnostic techniques and the introduction of novel antifungal agents, therapy for CNS infections is still associated with discouragingly poor results. In patients with haematological malignancies, opportunistic infections with Candida or Aspergillus remain the most common infections affecting the CNS; however, opportunistic infections with less well-known fungi are becoming more common and must be considered in the differential diagnosis. New techniques for the early diagnosis of invasive fungal infections are emerging. Pharmacologic options for treating invasive fungal infections have also improved during the past few years, with new drugs becoming available that have broader antifungal spectra and better safety profiles. Other novel treatment approaches, such as combination therapy, are also being explored. Early investigations have produced encouraging results; however, large, prospective studies involving many patients are necessary to validate the widespread use of these approaches. This review analyses the existing guidelines for treatment of CNS fungal infections and the literature available on the use of new drugs to generate sets of recommendations for treatment of these life-threatening infections in patients with haematological malignancies.