Fungal diagnosis: how do we do it and can we do better?

Fusarium and Neocosmospora: fungal priority pathogens in laboratory diagnosis

Fusarium and Neocosmospora are two fungal genera recently recognized in the list of fungal priority pathogens. They cause a wide range of diseases that affect humans, animals, and plants. In clinical laboratories, there is increasing concern about diagnosis due to limitations in sample collection and morphological identification. Despite the advances in molecular diagnosis, due to the cost, some countries cannot implement these methodologies. However, recent changes in taxonomy and intrinsic resistance to antifungals reveal the necessity of accurate species-level identification. In this review, we discuss the current phenotypic and molecular tools available for diagnosis in clinical laboratory settings and their advantages and disadvantages.

PET Imaging of Active Invasive Fungal Infections with d-[5-11C]-Glutamine

The increasing prevalence and severity of invasive fungal infections (IFIs), especially in immunocompromised populations, has amplified the need for rapid diagnosis of fungal pathogens. Radiotracers derived from d-amino acids (DAAs) show promise as bacterial-specific positron emission tomography (PET) imaging agents due to their preferential consumption by bacteria and largely nonutilization by hosts. Unlike mammals, fungi can utilize external DAAs including d-glutamine for their growth by rapidly upregulating DAA oxidases. Additionally, glutamine is essential for fungal nitrogen assimilation, survival, and virulence. We previously validated d-[5-11C]-glutamine (d-[5-11C]-Gln) as an efficient radiotracer targeting live bacterial soft-tissue infections. Here, we further expanded this investigation to evaluate its translational potential for PET imaging of IFIs in immunocompetent mouse models subcutaneously (SubQ) and intramuscularly (IM) infected with Candida albicans (C. albicans), using its l-isomer counterpart (l-[5-11C]-Gln) as a control. Comparative studies between pathogens showed significantly (p < 0.05) higher uptake in fungi (C. albicans and C. tropicalis) versus tested bacterial species for d-[5-11C]-Gln, suggesting that it could potentially serve as a more sensitive radiotracer for detection of fungal infections. Additionally, comparative PET imaging studies in immunocompetent infected mice demonstrated significantly higher infection-to-background ratios for d- versus l-[5-11C]-Gln in both SubQ (ratio = 1.97, p = 0.043) and IM (ratio = 1.97, p = 0.028) infections. Fungal infection imaging specificity was confirmed with no significant difference observed between localized inflammation sites versus untreated muscle background (heat-killed injection site/untreated muscle: ∼1.1). Taken together, this work demonstrates the translational potential of d-[5-11C]-Gln for noninvasive PET imaging of IFIs.

Long-Reads-Based Metagenomics in Clinical Diagnosis With a Special Focus on Fungal Infections

Identification of the causative infectious agent is essential in the management of infectious diseases, with the ideal diagnostic method being rapid, accurate, and informative, while remaining cost-effective. Traditional diagnostic techniques rely on culturing and cell propagation to isolate and identify the causative pathogen. These techniques are limited by the ability and the time required to grow or propagate an agent in vitro and the facts that identification based on morphological traits are non-specific, insensitive, and reliant on technical expertise. The evolution of next-generation sequencing has revolutionized genomic studies to generate more data at a cheaper cost. These are divided into short- and long-read sequencing technologies, depending on the length of reads generated during sequencing runs. Long-read sequencing also called third-generation sequencing emerged commercially through the instruments released by Pacific Biosciences and Oxford Nanopore Technologies, although relying on different sequencing chemistries, with the first one being more accurate both platforms can generate ultra-long sequence reads. Long-read sequencing is capable of entirely spanning previously established genomic identification regions or potentially small whole genomes, drastically improving the accuracy of the identification of pathogens directly from clinical samples. Long-read sequencing may also provide additional important clinical information, such as antimicrobial resistance profiles and epidemiological data from a single sequencing run. While initial applications of long-read sequencing in clinical diagnosis showed that it could be a promising diagnostic technique, it also has highlighted the need for further optimization. In this review, we show the potential long-read sequencing has in clinical diagnosis of fungal infections and discuss the pros and cons of its implementation.

Prevalence of pulmonary mycoses in smear-negative patients with suspected tuberculosis in the Brazilian Amazon

BACKGROUND

Pulmonary mycoses resemble clinically and radiologically chronic pulmonary tuberculosis. Studies describing the prevalence, etiology and clinical features of pulmonary mycosis are of crucial importance in the Brazilian Amazon.

AIMS

To estimate the frequency of pulmonary mycoses in smear-negative tuberculosis patients; to describe their demographic, epidemiological, and clinical characteristics; and to evaluate diagnostic methods.

METHODS

A cross-sectional study was conducted at two tuberculosis reference institutions in Amazonas, Brazil. We included 213 patients and collected clinical data, blood and induced sputum to perform serological, direct microscopy, microbiologic culture and PCR-based assays to identify infections caused by Aspergillus fumigatus, Paracoccidioides brasiliensis, Histoplasma capsulatum, Cryptococcus, and HIV. Chest computed tomography was also performed.

RESULTS

Pulmonary mycoses were diagnosed in 7% (15/213) of the cases, comprising ten aspergillosis cases, three cases of paracoccidioidomycosis and one case each of histoplasmosis and cryptococcosis. Among the patients with pulmonary mycoses, 86.7% were former tuberculosis patients. The most significant clinical characteristics associated with pulmonary mycoses were cavity-shaped lung injuries, prolonged chronic cough and hemoptysis.

CONCLUSIONS

Our study confirmed the high prevalence of pulmonary mycoses in smear-negative tuberculosis patients in the Brazilian Amazon.

Ultrastructural Study of Cryptococcus neoformans Surface During Budding Events

Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals. It is surrounded by three concentric structures that separate the cell from the extracellular space: the plasma membrane, the cell wall and the polysaccharide (PS) capsule. Although several studies have revealed the chemical composition of these structures, little is known about their ultrastructural organization and remodeling during C. neoformans budding events. Here, by combining the latest and most accurate light and electron microscopy techniques, we describe the morphological remodeling that occurs among the capsule, cell wall and plasma membrane during budding in C. neoformans. Our results show that the cell wall deforms to generate a specialized region at one of the cell’s poles. This region subsequently begins to break into layers that are slightly separated from each other and with thick tips. We also observe a reorganization of the capsular PS around the specialized regions. While daughter cells present their PS fibers aligned in the direction of budding, mother cells show a similar pattern but in the opposite direction. Also, daughter cells form multilamellar membrane structures covering the continuous opening between both cells. Together, our findings provide compelling ultrastructural evidence for C. neoformans surface remodeling during budding, which may have important implications for future studies exploring these remodeled specialized regions as drug-targets against cryptococcosis.

Dexamethasone and Methylprednisolone Promote Cell Proliferation, Capsule Enlargement, and in vivo Dissemination of C. neoformans

Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals, who often have some inflammatory condition and, therefore, end up using glucocorticoids, such as dexamethasone and methylprednisolone. Although the effects of this class of molecules during cryptococcosis have been investigated, their consequences for the biology of C. neoformans is less explored. Here, we studied the effects of dexamethasone and methylprednisolone on the metabolism and on the induction of virulence factors in C. neoformans. Our results showed that both glucocorticoids increased fungal cell proliferation and surface electronegativity but reduced capsule and secreted polysaccharide sizes, as well as capsule compaction, by decreasing the density of polysaccharide fibers. We also tested whether glucocorticoids could affect the fungal virulence in Galleria mellonella and mice. Although the survival rate of Galleria larvae increased, those from mice showed a tendency to decrease, with infected animals dying earlier after glucocorticoid treatments. The pathogenesis of spread of cryptococcosis and the interleukin secretion pattern were also assessed for lungs and brains of infected mice. While increases in the spread of the fungus to lungs were observed after treatment with glucocorticoids, a significant difference in brain was observed only for methylprednisolone, although a trend toward increasing was also observed for dexamethasone. Moreover, increases in both pulmonary and cerebral IL-10 production, reduction of IL-6 production but no changes in IL-4, IL-17, and INF-γ were also observed after glucocorticoid treatments. Finally, histopathological analysis confirmed the increase in number of fungal cells in lung and brain tissues of mice previously subjected to dexamethasone or methylprednisolone treatments. Together, our results provide compelling evidence for the effects of dexamethasone and methylprednisolone on the biology of C. neoformans and may have important implications for future clinical treatments, calling attention to the risks of using these glucocorticoids against cryptococcosis or in immunocompromised individuals.

Small-molecule inhibitors for the Prp8 intein as antifungal agents

Self-splicing proteins, called inteins, are present in many human pathogens, including the emerging fungal threats Cryptococcus neoformans (Cne) and Cryptococcus gattii (Cga), the causative agents of cryptococcosis. Inhibition of protein splicing in Cryptococcus sp. interferes with activity of the only intein-containing protein, Prp8, an essential intron splicing factor. Here, we screened a small-molecule library to find addititonal, potent inhibitors of the Cne Prp8 intein using a split-GFP splicing assay. This revealed the compound 6G-318S, with IC₅₀ values in the low micromolar range in the split-GFP assay and in a complementary split-luciferase system. A fluoride derivative of the compound 6G-318S displayed improved cytotoxicity in human lung carcinoma cells, although there was a slight reduction in the inhibition of splicing. 6G-318S and its derivative inhibited splicing of the Cne Prp8 intein in vivo in Escherichia coli and in C. neoformans Moreover, the compounds repressed growth of WT C. neoformans and C. gattii In contrast, the inhibitors were less potent at inhibiting growth of the inteinless Candida albicans Drug resistance was observed when the Prp8 intein was overexpressed in C. neoformans, indicating specificity of this molecule toward the target. No off-target activity was observed, such as inhibition of serine/cysteine proteases. The inhibitors bound covalently to the Prp8 intein and binding was reduced when the active-site residue Cys1 was mutated. 6G-318S showed a synergistic effect with amphotericin B and additive to indifferent effects with a few other clinically used antimycotics. Overall, the identification of these small-molecule intein-splicing inhibitors opens up prospects for a new class of antifungals.

Systemic mycoses: a potential alert for complications in COVID-19 patients

As the global COVID-19 pandemic spreads worldwide, new challenges arise in the clinical landscape. The need for reliable diagnostic methods, treatments and vaccines for COVID-19 is the major worldwide urgency. While these goals are especially important, the growing risk of co-infections is a major threat not only to the health systems but also to patients' lives. Although there is still not enough published statistical data, co-infections in COVID-19 patients found that a significant number of patients hospitalized with COVID-19 developed secondary systemic mycoses that led to serious complications and even death. This review will discuss some of these important findings with the major aim to warn the population about the high risk of concomitant systemic mycoses in individuals weakened by COVID-19.

Cell wall polysaccharides from pathogenic fungi for diagnosis of fungal infectious disease

Invasive fungal diseases are associated with significant morbidity and mortality, particularly in immunocompromised individuals. Early and accurate diagnosis is crucial for effective treatment. Despite traditional methods such as microbiological culture, histopathology, radiology and direct microscopy are available, antigen/antibody-based diagnostics are emerging for diagnosis of invasive fungal infections (IFI). Fungal cell wall is a unique structure composed of polysaccharides that are well correlated with fungal burden during fungal infections. Based on this feature, cell wall polysaccharides have been explored as antigens in IFIs diagnostics such as the galactomannan assay, mannan test, β-glucan assay and cryptococcal CrAg test. Herein, we provide an overview on the cell wall polysaccharides from three opportunistic pathogens: Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans, and their applications for IFIs diagnosis. The clinical outcome of newly developed cell wall polysaccharides-based diagnostics is also discussed.

Pathogen and host genetics underpinning cryptococcal disease

Cryptococcosis is a severe fungal disease causing 220,000 cases of cryptococcal meningitis yearly. The etiological agents of cryptococcosis are taxonomically grouped into at least two species complexes belonging to the genus Cryptococcus. All of these yeasts are environmentally ubiquitous fungi (often found in soil, leaves and decaying wood, tree hollows, and associated with bird feces especially pigeon guano). Infection in a range of animals including humans begins following inhalation of spores or aerosolized yeasts. Recent advances provide fundamental insights into the factors from both the pathogen and its hosts which influence pathogenesis and disease. The complex interactions leading to disease in mammalian hosts have also updated from the availability of better genomic tools and datasets. In this review, we discuss recent genetic research on Cryptococcus, covering the epidemiology, ecology, and evolution of Cryptococcus pathogenic species. We also discuss the insights into the host immune response obtained from the latest genetic modified host models as well as insights from monogenic disorders in humans. Finally we highlight outstanding questions that can be answered in the near future using bioinformatics and genomic tools.

Treatment of invasive fungal infections in intensive care units with micafungin: The MYRIADE study

BACKGROUND

Invasive fungal infections (IFIs) contribute significantly to nosocomial illness in intensive care units (ICUs). Current practice guidelines recommend echinocandins, such as micafungin, for the treatment of invasive candidiasis. However, limited information on their use in real-world practice is available.

OBJECTIVE

To describe the conditions of the use of micafungin in daily clinical practice and to evaluate its effectiveness and tolerability under real-world conditions.

PATIENTS/METHODS

This observational, prospective, multicentre study was performed in 34 ICUs in France. The study population consisted of 275 patients ≥16 years old who received treatment with micafungin during the inclusion period. Dose and duration of treatment were at the discretion of the physician.

RESULTS

Proven invasive candidiasis was documented before treatment in 106 patients (38.6%); 263 patients (95.6%) received the recommended dose (100 mg/day); 78 patients (28.8%) were treated for the recommended duration. A successful outcome was observed for 217 patients (79.2%). This proportion was significantly higher (83.3%; P < .0001) in patients treated for ≥14 days. Three patients discontinued treatment due to an adverse event considered related to micafungin. No clear impact of micafungin on hepatic function was observed.

CONCLUSION

Micafungin was effective in >75% of patients treated for IFIs in ICUs in France; outcomes may be improved with closer adherence to the recommended treatment duration.

Evaluation of a Novel Mitochondrial Pan-Mucorales Marker for the Detection, Identification, Quantification, and Growth Stage Determination of Mucormycetes

Mucormycosis infections are infrequent yet aggressive and serious fungal infections. Early diagnosis of mucormycosis and its discrimination from other fungal infections is required for targeted treatment and more favorable patient outcomes. The majority of the molecular assays use 18 S rDNA. In the current study, we aimed to explore the potential of the mitochondrial rnl (encoding for large-subunit-ribosomal-RNA) gene as a novel molecular marker suitable for research and diagnostics. Rnl was evaluated as a marker for: (1) the Mucorales family, (2) species identification (Rhizopus arrhizus, R. microsporus, Mucor circinelloides, and Lichtheimia species complexes), (3) growth stage, and (4) quantification. Sensitivity, specificity, discriminatory power, the limit of detection (LoD), and cross-reactivity were evaluated. Assays were tested using pure cultures, spiked clinical samples, murine organs, and human paraffin-embedded-tissue (FFPE) samples. Mitochondrial markers were found to be superior to nuclear markers for degraded samples. Rnl outperformed the UMD universal® (Molyzm) marker in FFPE (71.5% positive samples versus 50%). Spiked blood samples highlighted the potential of rnl as a pan-Mucorales screening test. Fungal burden was reproducibly quantified in murine organs using standard curves. Identification of pure cultures gave a perfect (100%) correlation with the detected internal transcribed spacer (ITS) sequence. In conclusion, mitochondrial genes, such as rnl, provide an alternative to the nuclear 18 S rDNA genes and deserve further evaluation.

Use of Micafungin for the Prevention and Treatment of Invasive Fungal Infections in Everyday Pediatric Care in France: Results of the MYRIADE Study

BACKGROUND

Invasive fungal infections are responsible for significant morbidity and mortality. Safety and effectiveness of antifungal agents is a particular concern in pediatric populations, where data are often limited. Micafungin is an echinocandin with demonstrated antifungal activity against a wide spectrum of Candida spp.; this subanalysis of data from the MYRIADE study describes the use of micafungin and its therapeutic outcomes in pediatric patients, in normal clinical practice.

METHODS

MYRIADE was an observational, multicenter, national, prospective, longitudinal study conducted from January 2010 to December 2012, in patients treated with micafungin using a prophylactic or curative strategy, across 17 sites [oncohematology (n = 8), neonatal intensive care units (ICUs) (n = 5) and pediatric ICUs (n = 4)]. The treatment regimen, the achievement of the therapeutic objective and the tolerance were reported.

RESULTS

The study population consisted of 110 pediatric patients (31 neonates, 24 children <2 years old and 55 children ≥2 to <16 years old). The therapeutic objective was achieved in 49/64 (76.6%) oncohematology patients, 28/29 (96.6%) neonatal ICU patients and 12/14 (85.7%) pediatric ICU patients. Twenty-four (21.8%) children developed an adverse event (AE); more AEs were observed in oncohematology patients compared with ICU patients [17 (26.1%) vs. 7 (15.6%)]. Only one serious AE, reported in an oncohematology patient, was considered related to micafungin.

CONCLUSIONS

In the first large observational study of micafungin treatment or prophylaxis conducted under real-world conditions in France, micafungin was effective and well tolerated for prophylaxis of invasive fungal infections in pediatric oncohematology patients and for curative purposes in pediatric and neonatal ICU patients.

Dermatologic Urgencies and Emergencies: What Every Pathologist Should Know

CONTEXT.—

Fatal dermatologic diseases and ones with high morbidity can occur in the inpatient setting. In such cases, prompt and accurate assessment of a bedside skin biopsy is required. This may be challenging for many pathologists who are not familiar with the complexity of skin pathology and skin terminology within the fields of dermatopathology and dermatology.

OBJECTIVE.—

To provide the pathologist with a practical, up-to-date, and "must-know" reference guide on dermatologic urgencies and emergencies from a real-world perspective, highlighting diagnostic pearls, diagnostic pitfalls, and commonly encountered practice gaps. This review will focus on key diseases with which every pathologist should be familiar, including angioinvasive fungal infections, Stevens-Johnson syndrome/toxic epidermal necrolysis, staph-scalded-skin syndrome, acute graft-versus-host disease, bullous pemphigoid, calciphylaxis, Sweet syndrome and its histiocytoid variant, pyoderma gangrenosum, and leukocytoclastic vasculitis, as well as those in their clinical and histopathologic differential.

DATA SOURCES.—

This review is based on peer-reviewed literature and our personal experiences with these diseases at major academic institutions, including one where a large number of stem cell transplants are performed. This review is unique as it represents collaborative expert opinion from both a dermatopathology and a dermatology standpoint.

CONCLUSIONS.—

This review outlines the critical role that the pathologist plays in the outcomes of patients with dermatologic urgencies and emergencies. Improved patient care will result from prompt and accurate histopathologic diagnoses as well as an open line of communication with the dermatologist.

Comprehensive Evaluation of Compendial USP<71>, BacT/Alert Dual-T, and Bactec FX for Detection of Product Sterility Testing Contaminants

The emergence of cell therapy programs in large academic centers has led to an increasing demand for clinical laboratories to assist with product sterility testing. Automated blood culture systems have shown promise as alternatives to the manual USP<71> compendial method, but current published data are limited by small organism test sets, particularly for molds. In 2015, failure of the Bactec FX system to detect mold contamination in two products prompted us to evaluate three test systems (compendial USP<71>, Bactec FX, and BacT/Alert Dual-T) over seven different culture combinations, using 118 challenge organisms representative of the NIH current good manufacturing practice (cGMP) environment. At <96 h and <144 h for bacterial and fungal detection, respectively, the compendial USP<71> method significantly outperformed the Bactec FX system (84.7% versus 64.4%; P = 0.0006) but not the BacT/Alert system at 32.5°C (78.8%; P = 0.3116). Extended incubation to 360 h with terminal visual inspection improved sensitivity, without a significant difference between compendial USP<71> and BacT/Alert testing (95.7% versus 89.0%; P = 0.0860); both systems were better than the Bactec FX system (71.2%; P < 0.0001 and P = 0.0003, respectively). The Bactec FX and BacT/Alert systems performed equivalently for 30 isolates derived from clinical bloodstream infections, confirming system optimization for clinical organisms rather than environmental contaminants. Paired Sabouraud dextrose agar (SDA) plates were always positive for fungi within the acceptable time frame. This study shows that the Bactec FX system is suboptimal for product sterility testing, and it provides strong data to support the use of BacT/Alert testing at 32.5°C paired with a supplemental SDA plate as an acceptable alternative to the compendial USP<71> method for product sterility testing.

Cisplatin protects mice from challenge of Cryptococcus neoformans by targeting the Prp8 intein

The Prp8 intein is one of the most widespread eukaryotic inteins, present in important pathogenic fungi, including Cryptococcus and Aspergillus species. Because the processed Prp8 carries out essential and non-redundant cellular functions, a Prp8 intein inhibitor is a mechanistically novel antifungal agent. In this report, we demonstrated that cisplatin, an FDA-approved cancer drug, significantly arrested growth of Prp8 intein-containing fungi C. neoformans and C. gattii, but only poorly inhibited growth of intein-free Candida species. These results suggest that cisplatin arrests fungal growth through specific inhibition of the Prp8 intein. Cisplatin was also found to significantly inhibit growth of C. neoformans in a mouse model. Our results further showed that cisplatin inhibited Prp8 intein splicing in vitro in a dose-dependent manner by direct binding to the Prp8 intein. Crystal structures of the apo- and cisplatin-bound Prp8 inteins revealed that two degenerate cisplatin molecules bind at the intein active site. Mutation of the splicing-site residues led to loss of cisplatin binding, as well as impairment of intein splicing. Finally, we found that overexpression of the Prp8 intein in cryptococcal species conferred cisplatin resistance. Overall, these results indicate that the Prp8 intein is a novel antifungal target worth further investigation.

Single human B cell-derived monoclonal anti-Candida antibodies enhance phagocytosis and protect against disseminated candidiasis

The high global burden of over one million annual lethal fungal infections reflects a lack of protective vaccines, late diagnosis and inadequate chemotherapy. Here, we have generated a unique set of fully human anti-Candida monoclonal antibodies (mAbs) with diagnostic and therapeutic potential by expressing recombinant antibodies from genes cloned from the B cells of patients suffering from candidiasis. Single class switched memory B cells isolated from donors serum-positive for anti-Candida IgG were differentiated in vitro and screened against recombinant Candida albicans Hyr1 cell wall protein and whole fungal cell wall preparations. Antibody genes from Candida-reactive B cell cultures were cloned and expressed in Expi293F human embryonic kidney cells to generate a panel of human recombinant anti-Candida mAbs that demonstrate morphology-specific, high avidity binding to the cell wall. The species-specific and pan-Candida mAbs generated through this technology display favourable properties for diagnostics, strong opsono-phagocytic activity of macrophages in vitro, and protection in a murine model of disseminated candidiasis.

Late diagnosis and ineffective treatment of fungal infections lead to high mortality. Here, Rudkin et al. generate anti-Candida human monoclonal antibodies with diagnostic and therapeutic potential, by expressing recombinant antibodies from genes cloned from B cells of patients suffering candidiasis.

Comparative study of primary pulmonary cryptococcosis with multiple nodules or masses by CT and pathology

The manifestations of pulmonary cryptococcosis with multiple nodules or masses on computed tomography (CT) are diverse and difficult to differentiate from those of lung cancer and pulmonary tuberculosis. The present study compared the multislice spiral CT signs with pathological results and used the pathological results to explain the CT signs with the aim of improving the accuracy of the diagnosis of this disease. A retrospective analysis of 20 patients with primary pulmonary cryptococcosis with multiple nodules or masses was performed. Based on the CT signs, eight patients had been misdiagnosed with lung cancer accompanied by intrapulmonary metastasis andthree patients had been misdiagnosed with tuberculosis. The major CT manifestations were a cluster of nodules or masses located within 2 cm below the pleura and distributed along the bronchi. A total of nine patients had primary lesions with diameters of 1.1–2.0 cm and 12 patients had satellite lesions with diameters of 0.1–1.0 cm. Regarding treatment, 5 patients underwent surgical monotherapy, 12 patients underwent antifungal monotherapy and three patients received surgery in combination with antifungal therapy. HE staining indicated that Cryptococcus neoformans was engulfed by macrophages, which were surrounded by massive infiltrating lymphocytes and a large amount of fibrous tissue, which formed multinucleated macrophages or granulomas. Periodic acid-Schiff staining was positive and acid fast staining was negative. In conclusion, comparison of CT signs with the pathological manifestation of pulmonary cryptococcosis with multiple nodules or masses indicated that the pathological results may explain certain imaging signs. Combination of CT and pathological examination may provide a deeper understanding of this disease and improve the accuracy of its diagnosis.

Role of the small GTPase Rho1 in cell wall integrity, stress response, and pathogenesis of Aspergillus fumigatus

Aspergillus fumigatus is a major pathogen of invasive pulmonary aspergillosis. The small GTPase, Rho1, of A. fumigatus is reported to comprise a potential regulatory subunit of β-1,3-glucan synthase and is indispensable for fungal viability; however, the role of AfRho1 on the growth, cell wall integrity, and pathogenesis of A. fumigatus is still poorly understood. We constructed A. fumigatus mutants with conditional- and overexpression of Rho1 and found that defects of AfRho1 expression led to the reduction of β-1,3-glucan and glucosamine moieties on the cell wall, with down-regulated transcription of genes in the cell wall integrity signaling pathway and a decrease of calcofluor white (CFW)-stimulated mitogen-activated protein kinase (MpkA) phosphorylation and cytoplasmic leakage compared to those of the wild-type strain (WT). In addition, down-regulation of AfRho1 expression caused much higher sensitivity of A. fumigatus to H₂O₂ and alkaline pH compared to that of WT. Decrease of AfRho1 expression also attenuated the A. fumigatus pathogenicity in Galleria mellonella and inhibited conidial internalization into lung epithelial cells and inflammatory factor release. In contrast, overexpression of Rho1 did not alter A. fumigatus morphology, susceptibility to cell wall stresses, or pathogenicity relative to its parental strain. Taken together, our findings support AfRho1 as an essential regulator of the cell wall integrity, stress response, and pathogenesis of A. fumigatus.

Use of Galactomannan Antigen and Aspergillus DNA Real-time Polymerase Chain Reaction as Routine Methods for Invasive Aspergillosis in Immunosuppressed Children in Greece

PURPOSE

Invasive aspergillosis (IA) remains a critical issue in immunosuppressed patients. Detection of galactomannan antigen (GM) in serum samples is included as a criterion of IA by the European Organization for the Research and Treatment of Cancer/Mycoses Study Group. Nevertheless, Aspergillus DNA detection by polymerase chain reaction (PCR) has not yet been included because clinical data validation is lacking. The present study describes the simultaneous performance of GM and PCR tests as routine methods for IA diagnosis.

METHODS

During the period January 2012 to December 2017, a total of 156 white children hospitalized in a tertiary children's hospital of Athens (97 boys and 59 girls; age range, 5 months-14 years) were examined as possible cases of IA. Patients were classified into 4 groups based on their underlying diseases: hematologic malignancies (107 of 156 [68.6%]), solid tumors (16 of 156 [10.2%]), primary immunodeficiency (12 of 156 [7.7%]), and hereditary immunodeficiency (21 of 156 [13.5%]). GM detection was made with the Platelia Aspergillus Ag kit (Bio-Rad Laboratories, Hercules, California). Sera with a cut-off index ≥0.5 on at least 2 separate blood collections were considered positive. Serum detection of Aspergillus DNA was conducted with real-time PCR MycAssay Aspergillus assay (Myconostica Ltd, Cambridge, United Kingdom). PCR positivity was determined by using a threshold of 38 cycles in at least 1 serum sample. Four or more successive samples per patient were tested.

FINDINGS

Overall, 28 of 156 patients (53 of 744 serum samples) were found positive. Eleven patients were positive using both methods (24 samples). Four children were positive only by PCR (6 samples), whereas 13 (23 samples) were positive only with GM in consecutive samples. Agreement of both methods, GM(+)/PCR(+) or GM(-)/PCR(-), was found in 139 patients (90% of total patients) and 715 samples (96.1% of total samples). The agreement of both methods was found: (1) 85% in patients with hematologic malignancies; (2) 100% in patients with solid tumors; (3) 97.5% in patients with primary immunodeficiency; and (4) 98.8% in patients with hereditary immunodeficiency. Overall disagreement was observed in 17 patients, in which the positive result in any of the 2 methods was estimated as true positive in conjunction with radiologic and other clinical findings.

IMPLICATIONS

The combination of GM and PCR, provided high diagnostic accuracy in consecutive samples (twice a week). Clinical, radiologic, and other laboratory findings should be taken into consideration in the evaluation of GM and PCR.

Molecular detection of fungal pathogens in clinical specimens by 18S rDNA high-throughput screening in comparison to ITS PCR and culture

The rising incidence of invasive fungal infections and the expanding spectrum of fungal pathogens makes early and accurate identification of the causative pathogen a daunting task. Diagnostics using molecular markers enable rapid identification of fungi, offer new insights into infectious disease dynamics, and open new possibilities for infectious disease control and prevention. We performed a retrospective study using clinical specimens (N = 233) from patients with suspected fungal infection previously subjected to culture and/or internal transcribed spacer (ITS) PCR. We used these specimens to evaluate a high-throughput screening method for fungal detection using automated DNA extraction (QIASymphony), fungal ribosomal small subunit (18S) rDNA RT-PCR and amplicon sequencing. Fungal sequences were compared with sequences from the curated, commercially available SmartGene IDNS database for pathogen identification. Concordance between 18S rDNA RT-PCR and culture results was 91%, and congruence between 18S rDNA RT-PCR and ITS PCR results was 94%. In addition, 18S rDNA RT-PCR and Sanger sequencing detected fungal pathogens in culture negative (N = 13) and ITS PCR negative specimens (N = 12) from patients with a clinically confirmed fungal infection. Our results support the use of the 18S rDNA RT-PCR diagnostic workflow for rapid and accurate identification of fungal pathogens in clinical specimens.

Clinical characteristics and treatment outcomes of pulmonary invasive fungal infection among adult patients with hematological malignancy in a medical centre in Taiwan, 2008-2013

BACKGROUND/PURPOSE

This study was aimed to investigate clinical characteristics and treatment outcomes of pulmonary invasive fungal infection (IFI) among patients with hematological malignancy.

METHODS

All patients with hematological malignancy who were treated at a medical centre from 2008 to 2013 were evaluated. Pulmonary IFI was classified according to the European Organization for Research and Treatment of Cancer 2008 consensus.

RESULTS

During the study period, 236 (11.3%) of 2083 patients with hematological malignancy were diagnosed as pulmonary IFI, including 41 (17.4%) proven, 75 (31.8%) probable, and 120 (50.8%) possible cases. Among the 116 patients of proven and probable cases of pulmonary IFI, aspergillosis alone (n = 90, 77.6%) was predominant, followed by cryptococcosis alone (n = 9, 7.8%), and mucormycosis (n = 4, 3.4%). The overall incidence of patients with pulmonary IFI was 5.9 per 100 patient-years. The highest incidence (per 100 patient-year) was found in patients with acute myeloid leukaemia (13.7) followed by acute lymphoblastic leukaemia (11.3), and myelodysplastic syndrome/severe aplastic anaemia (6.7). Fourteen (5.9%) of the 236 patients with pulmonary IFI died within 12 weeks after diagnosis of pulmonary IFI. Univariate analysis revealed that elderly age (>65 years) (P = 0.034), lack of response to anti-fungal treatment (P < 0.001), and admission to the intensive care unit (ICU) (P < 0.001) were predictors of poor prognosis. However, only admission to the ICU was an independent predictor of poor prognosis for 12-week mortality (P = 0.022) based on multivariate analysis.

CONCLUSION

Patients with acute leukaemia and myelodysplastic syndrome/severe aplastic anaemia were at high risk of pulmonary IFI.

Lung Infections

A review of pulmonary infections of all types with diagnostic and morphological features.

Novel recombinant multiepitope proteins for the detection of anti-Cryptococcus antibodies

AIM

To produce and test recombinant multiepitope proteins as an alternative assay for the serological diagnosis of cryptococcosis.

MATERIALS & METHODS

Previously, synthetic peptides were used to detect anti-Cryptococcus antibodies, and in silico analyses showed that the union of peptides would improve the results. Here, the coding sequences of these peptides were assembled into synthetic genes. Four genes have been cloned and expressed in Escherichia coli, producing recombinant multiepitope proteins: proteins A, B, C and D.

RESULTS

All constructs yielded good results; however, protein D showed the best results, with a sensitivity of 88.57% and specificity of 100%.

CONCLUSION

The multiepitope proteins were shown to be potential antigens for the diagnosis of cryptococcosis in an attempt to detect anti-Cryptococcus antibodies.

Evaluation of the diagnostic performance of panfungal polymerase chain reaction assay in invasive fungal diseases

Timely diagnosis of invasive fungal diseases (IFDs) is important, as delays in treatment initiation are associated with increased mortality rates. However, early diagnosis of IFDs in immunocompromised patients remains difficult. The conventional diagnostic methods currently used for IFDs are not sufficiently effective. Molecular tests, such as polymerase chain reaction (PCR)-based assays, have great potential to improve the early diagnosis of IFDs due to their sensitivity and specificity. In the present study, the diagnostic performance of panfungal PCR assays in IFD patients who received bone marrow transplantation was evaluated. The results suggested that panfungal PCR assay offered a quick and convenient guide for clinical decision-making by identifying higher numbers of fungal species in comparison with the conventional blood culture method. Furthermore, panfungal PCR assay exhibited a sensitivity of 93% and a specificity of 71% in the diagnosis of IFD patients based on the EORTC/MSG criteria. Thus, the present study concluded that the reported PCR-based method was effective and sensitive in early IFD diagnosis and should be integrated into clinical decision-making for the treatment of IFDs in the future.

Factors associated with early mycological clearance in HIV-associated cryptococcal meningitis

INTRODUCTION

The first-line combination therapy for HIV-associated cryptococcal meningitis (CM), a condition of high mortality particularly in the first two weeks of treatment, consists of amphotericin B plus flucytosine (5-FC). Given that 5-FC remains unavailable in many countries, the knowledge of factors influencing mycological clearance in patients treated with second-line therapy could contribute to effective management.

OBJECTIVES

To determine the factors associated with the clearance of Cryptococcus sp. from the cerebrospinal fluid by the second week of effective antifungal therapy (early mycological clearance) in HIV-associated CM.

METHODS

Retrospective cohort study based on secondary data corresponding to HIV-associated CM cases hospitalized at a tertiary health care center in Lima, Peru where 5-FC remains unavailable. Risk factors associated with early mycological clearance were analyzed by generalized linear regression models.

RESULTS

From January 2000 to December 2013, 234 individuals were discharged with a diagnosis of HIV-associated CM; in 215 we retrieved the required data. The inpatient mortality was 20% (43/215), 15 of them in the first two weeks of treatment. In the final model (157 cases), adjusted for age, previous episode of CM, ART use, type of antifungal treatment, raised intracranial pressure, frequency of therapeutic lumbar punctures, baseline fungal burden and treatment period, the factors associated with early mycological clearance were: Amphotericin B deoxycholate plus fluconazole as combination therapy (RR, 1.56; 95% CI, 1.14-2.14); severe baseline intracranial pressure (≥35 cm H2O) (RR, 0.57; 95% CI, 0.33-0.99); and baseline fungal burden over 4.5 log10 CFU/mL (RR, 0.61 95% CI: 0.39-0.95).

CONCLUSIONS

In a setting without access to first-line therapy for CM, the combination therapy with amphotericin B deoxycholate plus fluconazole was positively associated with early mycological clearance, while high fungal burden and severe baseline intracranial pressure were negatively associated, and thus related to failure.

Evaluation of the possible influence of trailing and paradoxical effects on the clinical outcome of patients with candidemia

OBJECTIVE

Paradoxical growth (PG) and trailing effect (TE) are frequently observed during antifungal susceptibility testing (AFST). These two phenomena interfere with the determination of the minimal inhibitory concentration (MIC). The aim of this study was to assess the clinical impact of TE and PG.

METHODS

We analysed the frequency of TE and PG of 690 Candida isolates collected from a population-based study performed in Spain (CANDIPOP) and correlated the results with clinical outcome of the patients.

RESULTS

Around 70% (484/690) of the isolates exhibited TE to azoles. Candida tropicalis showed the highest presence of TE (39/53 isolates exhibited residual growth >25% of control). No TE was seen in most of the isolates from the psilosis complex. PG was mainly associated with echinocandins. In patients treated with fluconazole within the first 48 hours after blood sampling (n = 221), the presence of TE to azoles tended to be associated with lower 30-day mortality (odds ratio (OR) 0.55, 95% confidence interval (CI) 0.25-1.00) but not with clinical failure (OR 0.85, 95% CI 0.45-1.54). In the subgroup of 117 patients treated with echinocandins, the presence of PG was not associated with patient's response to antifungal treatment (OR for 30-day mortality 1.63, 95% CI 0.76-4.03; OR for clinical failure 1.17, 95% CI 0.53-2.70).

CONCLUSIONS

TE or PG are widely expressed among Candida spp., although they do not seem to influence clinical outcome.

Equine Pulmonary Cryptococcosis: A Comparative Literature Review and Evaluation of Fluconazole Monotherapy

Cryptococcus is the most common fungal respiratory pathogen in Australian horses, manifesting primarily as pulmonary granulomas. Disease severity at presentation is dependent on the athletic use of the horse. The diagnosis and estimation of disease severity are centred around clinical findings, cytological evaluation of respiratory tract secretions, diagnostic imaging, and antigen titre testing. Both the lateral flow assay and the latex cryptococcal antigen titre are used, and important similarities and differences between species are discussed. Cryptococcus gattii occurs with greater frequency than Cryptococcus neoformans in equine pulmonic cryptococcosis and can be successfully treated with enteral fluconazole monotherapy, with disease severity determining treatment length.

Similar efficacy of broad-range ITS PCR and conventional fungal culture for diagnosing fungal infections in non-immunocompromised patients

Background

Broad-range fungal inter spacer region (ITS) polymerase chain reaction (PCR) has been evaluated for the detection and identification of fungi in clinical specimens from severely immunocompromised patients, but not in non-selected patients. Thus, the aim of this study was to compare the diagnostic performance of ITS PCR with that of fungal culture and to investigate its clinical impact on the diagnosis of fungal infections in non-immunocompromised patients. The corresponding patients’ data were retrieved by detailed medical chart reviews.

Results

Results from 251 specimens showed a high concordance of 89.6 % for ITS PCR and fungal culture. The analytical sensitivity and specificity of ITS PCR considering culture as gold standard were 87.7 and 90.3 %, respectively, the positive and negative predictive value (PPV and NPV) were 76 and 95.5 %, respectively. Assessing the clinical probability of a fungal infection based on detailed chart reviews, PCR had a clinical sensitivity of 88.9 %, a specificity of 86.3 %, a PPV of 64.0 % and a NPV of 96.6 %. The overall performance of fungal broad-range PCR was similar to that of culture.

Conclusions

Our data show that, in non-selected and non-immunocompromised patients, the performance of ITS PCR is similar to that of culture for detecting fungal infections, not the least because sensitivity of culture in patients under antifungal treatment is surprisingly high. Compared to culture, PCR has the advantage of a rapid time-to-result (approximately two working days), proper identification of rare pathogens, prompt initiation of a species-targeted antifungal treatment, and prospects for automation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-016-0752-1) contains supplementary material, which is available to authorized users.

Invasive aspergillosis successfully treated by combined antifungal therapy and immunosuppressive monotherapy two months following heart transplantation

Invasive aspergillosis is becoming increasingly prevalent, especially following transplantation. Invasive aspergillosis is associated with mortality. Successful therapy is related to early diagnosis and proper therapy. We present the case of a 61-year-old man suffering from invasive aspergillosis 2 months following heart transplantation. He was suffering from hypertrophic cardiomyopathy and he underwent orthotropic heart transplantation. He was readmitted to the Department of Cardiology 69 days following transplantation due to symptoms of productive cough for 5 days. It was accompanied by chest pain, shortness of breath, and fever up to 39°C. He was slightly cyanotic and confused on physical examination. The patient's status deteriorated within the following 2 days. On bronchoscopic specimen examinations Aspergillus mould filaments were detected and the serum galactomannan index was 12.162. His blood saturation decreased to 85%. C-reactive protein serum level increased to 273 mg/l. The patient was admitted to the intensive care unit and intubated due to severe respiratory insufficiency. Computed tomography revealed massive, mostly homogeneous consolidation. The patient was treated with 200 mg of voriconazole and 50 mg of caspofungin daily. Caspofungin therapy was continued for 23 days and voriconazole was administered parenterally for 62 days. Voriconazole therapy was continued orally for 9 months. During combined antifungal therapy, the galactomannan serum index constantly decreased from 12.1 to 0.33 (end-point of caspofungin therapy) and to 0.23 (end-point of voriconazole parenteral administration). His immunosuppressive therapy was limited to calcineurin inhibitor (tacrolimus) monotherapy. Post-treatment imaging 9 months after diagnosis confirmed the efficacy of therapy as a lack of pulmonary infiltration associated with left apical peribronchial scarring as a result of treatment. The present case proved the efficiency of combined (voriconazole and caspofungin) antibiotic therapy in invasive pulmonary aspergillosis. Computed tomography findings followed by the serum galactomannan index are useful tools for early diagnosis. Additional modification of the immunosuppressive regimen can be performed safely in the early postoperative period in case of severe infection.

(1,3)-β-d-Glucan-based antifungal treatment in critically ill adults at high risk of candidaemia: an observational study

OBJECTIVES

To determine the effects of a strategy that uses serum (1,3)-β-d-glucan (BDG) results for antifungal treatment of ICU patients at high risk of invasive candidiasis.

PATIENTS AND METHODS

Adult patients admitted to the ICU from January 2012 to June 2014 were included if they exhibited sepsis at the time of BDG testing and they met Candida score components ≥3. A retrospective analysis of collected data was performed.

RESULTS

In total, 198 patients were studied. Of 63 BDG-positive patients, 47 with candidaemia and 16 with probable Candida infection, all [31.8% (63/198)] received antifungal therapy. Of 135 BDG-negative patients, 110 [55.5% (110/198)] did not receive antifungal therapy, whereas 25 [12.6% (25/198)] were initially treated. Overall, antifungal therapy was started in 88 cases (44.4%), mostly with echinocandins. Antifungals were discontinued in 14 of 25 patients, as negative BDG results became available, and in 16 BDG-false-positive patients for whom subsequent findings allowed candidaemia (and other forms of invasive candidiasis) to be ruled out. Candidaemia was diagnosed only in one patient who did not receive prior antifungal therapy. The median antifungal therapy duration in candidaemic patients differed significantly from that in non-candidaemic patients [14 (IQR, 6-18) days versus 4 (IQR, 3-7) days; P < 0.001]. Using this approach, antifungal therapy was avoided in ∼73% of potentially treatable patients and it was shortened in another ∼20%.

CONCLUSIONS

This study supports the use of serum BDG results in the management of systemic antifungal drug prescription in septic patients. These findings need to be confirmed in additional studies.

Evaluation of five conventional and molecular approaches for diagnosis of cryptococcal meningitis in non-HIV-infected patients

Cryptococcal meningitis (CM) is a life-threatening mycosis primarily occurring in HIV-infected individuals. Recently, non-HIV-infected hosts were increasingly reported to form a considerable proportion. However, the majority of the reported studies on the diagnosis of CM patients were performed on HIV-infected patients. For evaluation of various diagnostic approaches for CM in non-HIV-infected patients, a range of conventional and molecular assays used for diagnosis of CM were verified on 85 clinical CSFs from non-HIV-infected CM patients, including India ink staining, culture, a newly developed loop-mediated isothermal amplification (LAMP), the lateral flow assay (LFA) of cryptococcal antigen detection and a qPCR assay. The LFA had the highest positive detection rate (97.6%; 95% CI, 91.8-99.7%) in non-HIV-infected CM patients, followed by the LAMP (87.1%; 95% CI, 78.0-93.4%), the qPCR (80.0%; 95% CI, 69.9-87.9%), India ink staining (70.6%; 95% CI, 59.7-80.0%) and culture (35.3%; 95% CI, 25.2-46.4%). All culture positive specimens were correctly identified by the LFA.

Virulence of Cryptococcus sp. Biofilms In Vitro and In Vivo using Galleria mellonella as an Alternative Model

Cryptococcus neoformans and C. gattii are fungal pathogens that are most commonly found in infections of the central nervous system, which cause life-threatening meningoencephalitis and can grow as a biofilm. Biofilms are structures conferring protection and resistance of microorganism to the antifungal drugs. This study compared the virulence of planktonic and biofilm cells of C. neoformans and C. gattii in Galleria mellonella model, as well as, the quantification of gene transcripts LAC1, URE1, and CAP59 by real time PCR. All three of the genes showed significantly increased expressions in the biofilm conditions for two species of Cryptococcus, when compared to planktonic cells. C. neoformans and C. gattii cells in the biofilm forms were more virulent than the planktonic cells in G. mellonella. This suggests that the biofilm conditions may contribute to the virulence profile. Our results contribute to a better understanding of the agents of cryptococcosis in the host-yeast aspects of the interaction.

The signal peptide peptidase SppA is involved in sterol regulatory element-binding protein cleavage and hypoxia adaptation in Aspergillus nidulans

Using forward genetics, we revealed that the signal peptide peptidase (SPP) SppA, an aspartyl protease involved in regulated intramembrane proteolysis (RIP), is essential for hypoxia adaptation in Aspergillus nidulans, as well as hypoxia-sensitive mutant alleles of a sterol regulatory element-binding protein (SREBP) srbA and the Dsc ubiquitin E3 ligase complex dscA-E. Both null and dead activity [D337A] mutants of sppA failed to grow in hypoxia, and the growth defect of ΔsppA was complemented by nuclear SrbA-N381 expression. Additionally, SppA interacted with SrbA in the endoplasmic reticulum, where SppA localized in normoxia and hypoxia. Expression of the truncated SrbA-N414 covering the SrbA sequence prior to the second transmembrane region rescued the growth of ΔdscA but not of ΔsppA in hypoxia. Unlike ΔdscA and ΔdscA;ΔsppA double mutants, in which SrbA cleavage was blocked, the molecular weight of cleaved SrbA increased in ΔsppA compared to the control strain in immunoblot analyses. Overall, our data demonstrate the sequential cleavage of SrbA by Dsc-linked proteolysis followed by SppA, proposing a new model of RIP for SREBP cleavage in fungal hypoxia adaptation. Furthermore, the function of SppA in hypoxia adaptation was consistent in Aspergillus fumigatus, suggesting the potential roles of SppA in fungal pathogenesis.

Pulmonary aspergillosis diagnosed by endoscopic ultrasound fine-needle aspiration

Pulmonary aspergillosis generally occurs in patients with prolonged neutropenia or immunosupression. Definitive diagnosis depends on the demonstration of the organism in tissue, as positive culture result from sputum, needle biopsy, or bronchoalveolar lavage fluid. Even though endoscopic ultrasound (EUS) fine needle aspiration (FNA) of paraesophageal/mediastinal lesions has been used numerous times, this is the first case that reports an aspergilloma diagnosed by EUS-FNA, allowing us to reach a definitive diagnosis. We present a patient with a nodular lesion located in the right upper lobe lung, with ground-glass opacity. Upper EUS revealed an ill-defined hypoechoic paraesophageal lesion with a central annular image. Culture results from EUS-FNA were positive for Aspergillus fumigatus. There are no previous reports of EUS imaging features of pulmonary aspergillosis. We believe that this central annular image in an ill-defined hypoechoic paraesophageal lesion may be a characteristic feature.

[Cryptococcosis: a potential aetiology of facial ulceration]

Cutaneous cryptococcosis is an uncommon aetiology of chronic facial ulceration but which may be associated to a potentially lethal focus of cryptococcosis.

OBSERVATION

A 35-year-old AIDS patient under antiretroviral therapy, presented with a chronic facial ulceration. Histopathological examination of a biopsy of the facial ulceration showed an inflammatory granuloma and masses of yeasts. Mycological culture of the cerebrospinal fluid revealed Cryptococcus neoformans. The diagnosis of AIDS-related cutaneous cryptococcosis of the face and cryptococcal meningitis was concluded.

DISCUSSION

Cryptococcosis should be thought as a potential aetiology of a chronic facial ulceration in an AIDS patient. Screening of other foci of the cryptococcosis such as that of the central nervous system is mandatory. Mycological examinations are of great interest for the diagnosis in rare resources setting.

Diagnostic of Fungal Infections Related to Biofilms

Fungal biofilm-related infections, most notably those caused by the Candida and Aspergillus genera, need to be diagnosed accurately and rapidly to avoid often unfavorable outcomes. Despite diagnosis of these infections is still based on the traditional histopathology and culture, the use of newer, rapid methods has enormously enhanced the diagnostic capability of a modern clinical mycology laboratory. Thus, while accurate species-level identification of fungal isolates can be achieved with turnaround times considerably shortened, nucleic acid-based or antigen-based detection methods can be considered useful adjuncts for the diagnosis of invasive forms of candidiasis and aspergillosis. Furthermore, simple, reproducible, and fast methods have been developed to quantify biofilm production by fungal isolates in vitro. In this end, isolates can be categorized as low, moderate, or high biofilm-forming, and this categorization may reflect their differential response to the conventional antifungal therapy. By means of drug susceptibility testing performed on fungal biofilm-growing isolates, it is now possible to evaluate not only the activity of conventional antifungal agents, but also of novel anti-biofilm agents. Despite this, future diagnostic methods need to target specific biofilm components/molecules, in order to provide a direct proof of the presence of this growth phenotype on the site of infection. In the meantime, our knowledge of the processes underlying the adaptive drug resistance within the biofilm has put into evidence biofilm-specific molecules that could be potentially helpful as therapeutic targets. Surely, the successful management of clinically relevant fungal biofilms will rely upon the advancement and/or refinement of these approaches.

Thiamine antivitamins--an opportunity of therapy of fungal infections caused by Malassezia pachydermatis and Candida albicans

Severe skin diseases and systemic fungaemia are caused by Malassezia pachydermatis and Candida albicans respectively. Antifungal therapies are less effective because of chronic character of infections and high percentage of relapses. Therefore, there is a great need to develop new strategies of antifungal therapies. We previously found that oxythiamine decreases proliferation of yeast (Saccharomyces cerevisiae), therefore we suggest that thiamine antivitamins can be considered as antifungal agents. The aim of this study was the comparison of thiamine antivitamins (oxythiamine, amprolium, thiochrome, tetrahydrothiamine and tetrahydrooxythiamine) inhibitory effect on the growth rate and energetic metabolism efficiency in non-pathogenic S. cerevisiae and two potentially pathogenic species M. pachydermatis and C. albicans. Investigated species were cultured on a Sabouraud medium supplemented with trace elements in the presence (40 mg l(-1)) or absence of each tested antivitamins to estimate their influence on growth rate, enzyme activity and kinetic parameters of pyruvate decarboxylase and malate dehydrogenase of each tested species. Oxythiamine was the only antivitamin with antifungal potential. M. pachydermatis and S. cerevisiae were the most sensitive, whereas C. albicans was the least sensitive to oxythiamine action. Oxythiamine can be considered as supportive agent in superficial mycoses treatment, especially those caused by species from the genus Malassezia.

Diagnosis of Invasive Fungal Diseases in Hematological Malignancies: A Critical Review of Evidence and Turkish Expert Opinion (TEO-2)

One of the most problematic issues in hematological malignancies is the diagnosis of invasive fungal diseases. Especially, the difficulty of mycological diagnosis and the necessity of immediate intervention in molds have led to the adoption of “surrogate markers” that do not verify but rather strongly suggest fungal infection. The markers commonly used are galactomannan (GM), beta-glucan, and imaging methods. Although there are numerous studies on these diagnostic approaches, none of these markers serve as a support for the clinician, as is the case in human immunodeficiency virus (HIV) or cytomegalovirus (CMV) infections. This paper has been prepared to explain the diagnostic tests. As molecular tests have not been standardized and are not used routinely in the clinics, they will not be mentioned here.

Consensus guidelines for the treatment of yeast infections in the haematology, oncology and intensive care setting, 2014

Pathogenic yeast forms are commonly associated with invasive fungal disease in the immunocompromised host, including patients with haematological malignancies and patients of haemopoietic stem cell transplants. Yeasts include the Candida spp., Cryptococcus spp., Pneumocystis jirovecii and some lesser-known pathogens. Candida species remain the most common cause of invasive yeast infections (and the most common human pathogenic fungi). These guidelines present evidence-based recommendations for the antifungal management of established, invasive yeast infections in adult and paediatric patients in the haematology/oncology setting. Consideration is also given to the critically ill patient in intensive care units, including the neonatal intensive care unit. Evidence for 'pre-emptive' or 'diagnostic-driven antifungal therapy' is also discussed. For the purposes of this paper, invasive yeast diseases are categorised under the headings of invasive candidiasis, cryptococcosis and uncommon yeast infections. Specific recommendations for the management of Pneumocystis jirovecii are presented in an accompanying article (see consensus guidelines by Cooley et al. appearing elsewhere in this supplement).

Cryptococcal osteomyelitis in an adolescent survivor of T-cell acute lymphoblastic leukemia

Cryptococcosis is infrequent in children, and isolated cryptococcal osteomyelitis is rarely encountered. Here, we describe a 14-year-old patient in remission from T-cell acute lymphoblastic leukemia with osteomyelitis because of Cryptococcus neoformans var. grubii. The patient was effectively treated with antifungal therapy.

Aspergillus-Specific Lateral-Flow Device and Real-Time PCR Testing of Bronchoalveolar Lavage Fluid: a Combination Biomarker Approach for Clinical Diagnosis of Invasive Pulmonary Aspergillosis

Clinical experience with the impact of serum biomarkers for invasive fungal disease (IFD) varies markedly in hemato-oncology. Invasive pulmonary aspergillosis (IPA) is the most common manifestation, so we evaluated biomarkers in bronchoalveolar lavage (BAL) fluid. An Aspergillus-specific lateral-flow device (LFD), quantitative real-time PCR (qPCR), and the galactomannan (GM) test were used with 32 BAL fluid samples from 32 patients at risk of IPA. Eight patients had proven IPA, 3 had probable IPA, 6 had possible IPA, and 15 patients had no IPA by European Organization for Research and Treatment of Cancer Invasive Fungal Infections Cooperative Group/Mycoses Study Group of the National Institute of Allergy and Infectious Diseases (EORTC/MSG) criteria. The diagnostic accuracies of the tests were evaluated, and pairwise agreement between biomarkers was calculated. The diagnostic performance of the EORTC/MSG criteria was evaluated against the test(s) identified to be the most useful for IPA diagnosis. Using the EORTC/MSG criteria, the sensitivities of qPCR and LFD were 100% and the sensitivity of the GM test was 87.5% (GM test index cutoff, >0.8), with the tests having specificities of between 66.7 and 86.7%. The agreement between the results of qPCR and LFD was almost perfect (Cohen's kappa coefficient = 0.93, 95% confidence interval, 0.81 to 1.00). LFD and qPCR combined had a sensitivity of 100% and a specificity of 85.7%. Calcofluor staining and culture of all BAL fluid samples were negative for fungal infection. The median time from the start of mold-active antifungal therapy to the time of collection of BAL fluid was 6 days. Reversing roles and using dual testing by LFD and qPCR to classify cases, the EORTC/MSG criteria had a sensitivity of 83.3%. All three tests are useful for the diagnosis of IPA in BAL fluid samples. Despite the significant delays between the start of antifungal therapy and bronchoscopy, unlike microscopy and culture, the biomarkers remained informative. In particular, the combination of LFD and qPCR allows the sensitive and specific detection of IPA.

British Society for Medical Mycology best practice recommendations for the diagnosis of serious fungal diseases

Invasive fungal diseases are an important cause of morbidity and mortality in a wide range of patients, and early diagnosis and management are a challenge. We therefore did a review of the scientific literature to generate a series of key recommendations for the appropriate use of microbiological, histological, and radiological diagnostic methods for diagnosis of invasive fungal diseases. The recommendations emphasise the role of microscopy in rapid diagnosis and identification of clinically significant isolates to species level, and the need for susceptibility testing of all Aspergillus spp, if treatment is to be given. In this Review, we provide information to improve understanding of the importance of antigen detection for cryptococcal disease and invasive aspergillosis, the use of molecular (PCR) diagnostics for aspergillosis, and the crucial role of antibody detection for chronic and allergic aspergillosis. Furthermore, we consider the importance of histopathology reporting with a panel of special stains, and emphasise the need for urgent (<48 hours) and optimised imaging for patients with suspected invasive fungal infection. All 43 recommendations are auditable and should be used to ensure best diagnostic practice and improved outcomes for patients.