Differences in beta-glucan levels in culture supernatants of a variety of fungi

Colorimetric sensing for translational applications: from colorants to mechanisms

Colorimetric sensing offers instant reporting via visible signals. Versus labor-intensive and instrument-dependent detection methods, colorimetric sensors present advantages including short acquisition time, high throughput screening, low cost, portability, and a user-friendly approach. These advantages have driven substantial growth in colorimetric sensors, particularly in point-of-care (POC) diagnostics. Rapid progress in nanotechnology, materials science, microfluidics technology, biomarker discovery, digital technology, and signal pattern analysis has led to a variety of colorimetric reagents and detection mechanisms, which are fundamental to advance colorimetric sensing applications. This review first summarizes the basic components (e.g., color reagents, recognition interactions, and sampling procedures) in the design of a colorimetric sensing system. It then presents the rationale design and typical examples of POC devices, e.g., lateral flow devices, microfluidic paper-based analytical devices, and wearable sensing devices. Two highlighted colorimetric formats are discussed: combinational and activatable systems based on the sensor-array and lock-and-key mechanisms, respectively. Case discussions in colorimetric assays are organized by the analyte identities. Finally, the review presents challenges and perspectives for the design and development of colorimetric detection schemes as well as applications. The goal of this review is to provide a foundational resource for developing colorimetric systems and underscoring the colorants and mechanisms that facilitate the continuing evolution of POC sensors.

Lower (1,3)-beta-d-glucan sensitivity and in vitro levels in Candida auris and Candida parapsilosis strains

OBJECTIVES

The serum (1,3)-beta-d-glucan (BDG) assay gives quicker results and has higher sensitivity than blood cultures, therefore it is advised for early diagnosis of invasive candidemia and/or discontinuation of empirical therapy. Its sensitivity may depend on different factors. The aim of our study was to analyse the in vitro and in vivo BDG levels in clinical isolates of three species of Candida responsible for candidemia.

METHODS

C. albicans, C. parapsilosis, and C. auris strains were collected from blood cultures of patients who had a concurrent (-1 to +3 days) serum BDG test (Fungitell assay). Supernatants of all strains were tested in quadruplicate for BDG levels.

RESULTS

Twenty-two C. auris, 14 C. albicans, and ten C. parapsilosis strains were included. The median BDG levels in supernatants were 463 pg/mL (interquartile range [IQR] 379-648) for C. auris, 1080 pg/mL (IQR 830-1276) for C. albicans, and 755 pg/mL (IQR 511-930) for C. parapsilosis, with the significant difference among the species (p < 0.0001). Median serum BDG levels (IQR) were significantly lower in case C. auris and C. parapsilosis vs. C. albicans (p < 0.0001), respectively, 50 pg/mL (IQR 15-161) and 57 pg/mL (IQR 18-332), vs. 372 pg/mL (IQR 102-520). Sensitivity of serum BDG was 39% (95% confidence interval [CI], 18-64) in case of C. auris, 30% (95% CI, 8-65) C. parapsilosis and 78% (95% CI, 49-94) C. albicans candidemia.

DISCUSSION

In our centre C. auris and C. parapsilosis strains have lower BDG content as compared with C. albicans, with a potential impact on serum BDG performance for the diagnosis of candidemia.

Radioimmunotherapy as a pathogen-agnostic treatment method for opportunistic mucormycosis infections

Invasive fungal infections (IFIs) such as mucormycosis are causing devastating morbidity and mortality in immunocompromised patients as anti-fungal agents do not work in the setting of a suppressed immune system. The coronavirus disease 2019 (COVID-19) pandemic has created a novel landscape for IFIs in post-pandemic patients, resulting from severe immune suppression caused by COVID-19 infection, comorbidities (diabetes, obesity) and immunosuppressive treatments such as steroids. The antigen-antibody interaction has been employed in radioimmunotherapy (RIT) to deliver lethal doses of ionizing radiation emitted by radionuclides to targeted cells and has demonstrated efficacy in several cancers. One of the advantages of RIT is its independence of the immune status of a host, which is crucial for immunosuppressed post-COVID-19 patients. In the present work we targeted the fungal pan-antigens 1,3-beta-glucan and melanin pigment, which are present in the majority of pathogenic fungi, with RIT, thus making such targeting pathogen-agnostic. We demonstrated in experimental murine mucormycosis in immunocompetent and immunocompromised mice that lutetium-177 (177Lu)-labelled antibodies to these two antigens effectively decreased the fungal burden in major organs, including the brain. These results are encouraging because they show the effectiveness of pathogen-agnostic RIT in significantly decreasing fungal burden in vivo, while they can also potentially be applied to treat the broad range of invasive fungal infections that express the pan-antigens 1,3-beta-glucan or melanin.

Scedosporium infection disseminated "from toe to head" in allogeneic stem cell transplant recipient: a case report

BACKGROUND

Scedosporium is a lesser-known non-Aspergillus genus of mold that can present in unsuspecting ways. If overlooked, it may disseminate and cause high mortality in high-risk allogeneic stem cell transplant recipients.

CASE PRESENTATION

This case report describes a 65-year-old patient with Acute Myeloid Leukemia who underwent an allogeneic hematopoietic stem cell transplant after a period of prolonged neutropenia with fluconazole prophylaxis. She suffered severe debility with altered mentation from a S. apiospermum infection which likely disseminated from a toe wound to the lung and central nervous system. She was successfully treated with liposomal amphotericin B and voriconazole, but faced a prolonged recovery from physical and neurologic sequela.

CONCLUSIONS

The case highlights the importance of adequate anti-mold prophylaxis in high-risk patients, and the value of a thorough physical examination in this patient population, with particular attention to skin and soft tissue findings.

Genetic Mouse Models of Pneumocystis Pneumonia

Pneumocystis jirovecii causes pneumonia in immunocompromised patients. A major challenge in drug susceptibility testing and in understanding host/pathogen interactions is that Pneumocystis spp. are not viable in vitro. Continuous culture of the organism is not currently available, and therefore, developing new drug targets is very limited. Due to this limitation, mouse models of Pneumocystis pneumonia have proven to be an invaluable resource to researchers. In this chapter, we provide an overview of selected methods used in mouse models of infection including, in vivo Pneumocystis murina propagation, routes of transmission, genetic mouse models available, a P. murina life form-specific model, a mouse model of PCP immune reconstitution inflammatory syndrome (IRIS), and the experimental parameters associated with these models.

Lomentospora prolificans Disseminated Infections: A Systematic Review of Reported Cases

BACKGROUND

Lomentospora prolificans, a rare, highly virulent filamentous fungus with high rates of intrinsic resistance to antifungals, has been associated with different types of infections in immunocompromised as well as immunocompetent individuals.

OBJECTIVE

To systematically address all relevant evidence regarding L. prolificans disseminated infections in the literature.

METHODS

We searched Medline via PubMed and Scopus databases through July 2022. We performed a qualitative synthesis of published articles reporting disseminated infections from L. prolificans in humans.

RESULTS

A total of 87 studies describing 142 cases were included in our systematic review. The pathogen was most frequently reported in disseminated infections in Spain (n = 47), Australia (n = 33), the USA (n = 21), and Germany (n = 10). Among 142 reported cases, 48.5% were males. Underlying conditions identified for the majority of patients included malignancy (72.5%), hemopoietic stem cell transplantation (23.2%), solid organ transplantation (16%), and AIDS (2%). Lungs, central nervous system, skin, eyes, heart and bones/joints were the most commonly affected organs. Neutropenia was recorded in 52% of patients. The mortality rate was as high as 87.3%.

CONCLUSIONS

To the best of our knowledge, this is the first systematic review conducted on disseminated infections due to this rare microorganism. Physicians should be aware that L. prolificans can cause a diversity of infections with high mortality and primarily affects immunocompromised and neutropenic patients.

Parietal composition of Lichtheimia corymbifera: Differences between spore and germ tube stages and host-pathogen interactions

The molecular composition and structural organization of the cell wall of filamentous fungi underlie the ability of the host to identify them as pathogens. Although the organization of the fungal cell wall, composed of 90% polysaccharides, is similar from one fungus to another, small variations condition their ability to trigger pattern recognition receptors. Because the incidence of mucormycosis, an emerging life-threatening infection caused by the species of the order Mucorales is increasing worldwide, the precise composition of the cell wall of two strains of Lichtheimia corymbifera was investigated in the early growth stages of germination (spores and germ-tubes) using trimethylsilylation and confocal microscopy. This study also characterizes the response of THP-1 cells to Mucorales. The study identified the presence of uncommon monosaccharides (fucose, galactose, and glucuronic acid) whose respective proportions vary according to the germination stage, revealing early parietal reorganization. Immunofluorescence studies confirmed the exposure of β-glucan on the surface of swollen spores and germ-tubes. Both spores and germ-tubes of L. corymbifera promoted an early and strong pro-inflammatory response, through TLR-2. Our results show the singularity of the cell wall of the order Mucorales, opening perspectives for the development of specific diagnostic biomarkers.

Effect of Flagellin Pre-Exposure on the Inflammatory and Antifungal Response of Bronchial Epithelial Cells to Fungal Pathogens

Bronchial epithelial cells (BEC) play a crucial role in innate immunity against inhaled fungi. Indeed, in response to microorganisms, BEC synthesize proinflammatory cytokines involved in the recruitment of neutrophils. We have recently shown that BEC exert antifungal activity against Aspergillus fumigatus by inhibiting filament growth. In the present study, we first analyzed the inflammatory and antifungal responses of BEC infected by several fungal species such as Aspergillus spp., Scedosporium apiospermum and Candida albicans, which are frequently isolated from the sputum of people with chronic pulmonary diseases. The airways of these patients, such as people with cystic fibrosis (pwCF), are mainly colonized by P. aeruginosa and secondary by fungal pathogens. We have previously demonstrated that BEC are capable of innate immune memory, allowing them to increase their inflammatory response against A. fumigatus following a previous contact with Pseudomonas aeruginosa flagellin. To identify the impact of bacteria exposure on BEC responses to other fungal infections, we extended the analysis of BEC innate immune memory to Aspergillus spp., Scedosporium apiospermum and Candida albicans infection. Our results show that BEC are able to recognize and respond to Aspergillus spp., S. apiospermum and C. albicans infection and that the modulation of BEC responses by pre-exposure to flagellin varies according to the fungal species encountered. Deepening our knowledge of the innate immune memory of BEC should open new therapeutic avenues to modulate the inflammatory response against polymicrobial infections observed in chronic pulmonary diseases such as CF.

Invasive Fungal Infection Caused by Magnusiomyces capitatus in an Immunocompromised Pediatric Patient with Acute Lymphoblastic Leukemia in Mexico City: A Case Report

Magnusiomyces capitatus (also denominated “Geotrichum capitatum” and “the teleomorph stage of Saprochaete capitata”) mainly affects immunocompromised patients with hematological malignancies in rare cases of invasive fungal infections (IFIs). Few cases have been reported for pediatric patients with acute lymphoblastic leukemia (ALL), in part because conventional diagnostic methods do not consistently detect M. capitatus in infections. The current contribution describes a systemic infection in a 15-year-old female diagnosed with ALL. She arrived at the Children’s Hospital of Mexico City with a fever and neutropenia and developed symptoms of septic shock 4 days later. M. capitatus ENCB-HI-834, the causal agent, was isolated from the patient’s blood, urine, bile, and peritoneal fluid samples. It was identified with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and a phylogenetic reconstruction using internal transcribed spacer (ITS) and 28S ribosomal sequences. The phylogenetic sequence of M. capitatus ENCB-HI-834 clustered with other M. capitatus-type strains with a 100% identity. In vitro antifungal testing, conducted with the Sensititre YeastOne susceptibility system, found the following minimum inhibitory concentration (MIC) values (μg/mL): posaconazole 0.25, amphotericin B 1.0, fluconazole > 8.0, itraconazole 0.25, ketoconazole 0.5, 5-flucytosine ≤ 0.06, voriconazole 0.25, and caspofungin > 16.0. No clinical breakpoints have been defined for M. capitatus. This is the first clinical case reported in Mexico of an IFI caused by M. capitatus in a pediatric patient with ALL. It emphasizes the importance of close monitoring for a timely and accurate diagnosis of neutropenia-related IFIs to determine the proper treatment with antibiotics, antifungals, and chemotherapy for instance including children with ALL.

Lomentospora prolificans: An Emerging Opportunistic Fungal Pathogen

Lomentospora prolificans is an emerging opportunistic pathogen that primarily affects immunocompromised individuals leading to disseminated disease with high mortality rates while also causing infections in healthy populations. Successful recovery from infection is difficult due to high rates of intrinsic resistance to antifungals. Rapid and readily available diagnostic methods, aggressive surgical debridement wherever appropriate, and effective and timely antifungal treatment are the pillars for successful management. Future research will need to clarify the environmental niche of the fungus, further investigate the pathophysiology of infection and define species-specific therapeutic targets.

The Diagnostic Values of Peptidoglycan, Lipopolysaccharide, and (1,3)-Beta-D-Glucan in Patients with Suspected Bloodstream Infection: A Single Center, Prospective Study

This study aimed to assess the diagnostic values of peptidoglycan (PGN), lipopolysaccharide (LPS) and (1,3)-Beta-D-Glucan (BDG) in patients with suspected bloodstream infection. We collected 493 heparin anticoagulant samples from patients undergoing blood culture in Peking Union Medical College Hospital from November 2020 to March 2021. The PGN, LPS, and BDG in the plasma were detected using an automatic enzyme labeling analyzer, GLP-F300. The diagnostic efficacy for PGN, LPS, and BDG were assessed by calculating the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). This study validated that not only common bacteria and fungi, but also some rare bacteria and fungi, could be detected by testing the PGN, LPS, and BDG, in the plasma. The sensitivity, specificity, and total coincidence rate were 83.3%, 95.6%, and 94.5% for PGN; 77.9%, 95.1%, and 92.1% for LPS; and 83.8%, 96.9%, and 95.9% for BDG, respectively, which were consistent with the clinical diagnosis. The positive rates for PGN, LPS, and BDG and the multi-marker detection approach for PGN, LPS, and BDG individually were 11.16%, 17.65%, and 9.13%, and 32.86% significantly higher than that of the blood culture (p < 0.05). The AUC values for PGN, LPS, and BDG were 0.881 (0.814−0.948), 0.871 (0.816−0.925), and 0.897 (0.825−0.969), separately, which were higher than that of C-reactive protein (0.594 [0.530−0.659]) and procalcitonin (0.648 [0.587−0.708]). Plasma PGN, LPS, and BDG performs well in the early diagnosis of bloodstream infections caused by Gram-positive and Gram-negative bacterial and fungal pathogens.

Evaluating comparative β-glucan production aptitude of Saccharomyces cerevisiae, Aspergillus oryzae, Xanthomonas campestris, and Bacillus natto

β-glucan is a natural polysaccharide derivative composed of a group of glucose monomers with β-glycoside bonds that can be synthesized intra- or extra-cellular by various microorganisms such as yeasts, bacteria, and moulds. The study aimed to discover the potential of various microorganisms such as Saccharomyces cerevisiae, Aspergillus oryzae, Xanthomonas campestris, and Bacillus natto in producing β-glucan. The experimental method used and the data were analyzed descriptively. The four microorganisms above were cultured under a submerged state in Yeast glucose (YG) broth for 120 h at 30 °C with 200 rpm agitation. During the growth, several parameters were examined including total population by optical density, the pH, and glucose contents of growth media. β-glucan was extracted using acid-alkaline methods from the growth media then the weight was measured. The results showed that S. cerevisiae, A. oryzae X. campestris, and B. natto were prospective for β-glucans production in submerged fermentation up to 120 h. The highest β-glucans yield was shown by B. natto (20.38%) with the β-glucans mass of 1.345 ± 0.08 mg and globular diameter of 600 μm. The highest β-glucan mass was achieved by A. oryzae of 82.5 ± 0.03 mg with the total population in optical density of 0.1246, a final glucose level of 769 ppm, the pH of 6.67, and yield of 13.97% with a globular diameter of 1400 μm.

Beta-D-Glucan in Patients with Haematological Malignancies

(1-3)-beta-D-glucan (BDG) is an almost panfungal marker (absent in zygomycetes and most cryptococci), which can be successfully used in screening and diagnostic testing in patients with haematological malignancies if its advantages and limitations are known. The aim of this review is to report the data, particularly from the last 5 years, on the use of BDG in haematological population. Published data report mainly on the performance of the Fungitell™ assay, although several others are currently available, and they vary in method and cut-off of positivity. The sensitivity of BDG for invasive fungal disease (IFD) in haematology patients seems lower than in other populations, possibly because of the type of IFD (lower sensitivity was found in case of aspergillosis compared to candidiasis and pneumocystosis) or the use of prophylaxis. The specificity of the test can be improved by using two consecutive positive assays and avoiding testing in the case of the concomitant presence of factors associated with false positive results. BDG should be used in combination with clinical assessment and other diagnostic tests, both radiological and mycological, to provide maximum information. Good performance of BDG in cerebrospinal fluid (CSF) has been reported. BDG is a useful diagnostic method in haematology patients, particularly for pneumocystosis or initial diagnosis of invasive fungal infections.

β-1,3-D-glucan and galactomannan as biomarkers for the detection of invasive Geotrichum and Magnusiomyces infections: a retrospective evaluation

OBJECTIVES

Magnusiomyces and Geotrichum species are ascomycetous yeasts that can cause potentially life-threatening invasive fungal infections commonly referred to as geotrichosis. In this study, we aimed to estimate the incidence and mortality of these infections in a German tertiary care centre. Furthermore, we evaluated the suitability of the fungal biomarkers galactomannan (GM) and β-1,3-D-glucan (BDG), which are both recommended as surrogate markers for M. capitatus infection by the ESCMID and ECMM joint clinical guidelines for the diagnosis and management of rare invasive yeast infections, for detection of invasive geotrichosis.

METHODS

Cases meeting the inclusion criteria for invasive Magnusiomyces/Geotrichum infection were retrospectively identified. Serum samples and culture supernatants were analysed with two commercially available fungal antigen tests (Platelia Aspergillus Ag EIA and Wako β-Glucan Test). For a control cohort, outpatient samples sent for lues testing were included.

RESULTS

Thirty-eight cases of Magnusiomyces/Geotrichum infection were identified over an eleven-year observation period. In the majority of cases, the fungus was isolated from intraabdominal specimens of patients with a history of abdominal surgery/procedures (n=32). All cases of fungemia occurred exclusively in haemato-oncologic patients (n=14). 30 day-survival was 42% in the fungemia and 43% in the intraabdominal geotrichosis group. Serum samples were available for 23 patients (14 bloodstream and nine intraabdominal infections). While BDG sensitivity was 65%, none of the sera was GM positive. This finding was supported by in vitro experiments analysing fungal culture supernatants: M. capitatus secretes significant amounts of BDG but not GM. Specificity was 96% for BDG and 100% for GM.

CONCLUSIONS

Magnusiomyces and Geotrichum infections are not limited to haemato-oncologic patients. Contrasting the current ESCMID/ECMM recommendation, our results indicate that GM is no suitable biomarker for the diagnosis of Magnusiomyces infection. Contrarily, BDG sensitivity is comparable to that of candidemia.

Use of topical amphotericin in a case of refractory sino-orbital angioinvasive mucormycosis

The standard of care for treatment of sino-orbital mucormycosis involves aggressive surgical debridement and liposomal amphotericin, and the roles of adjunctive and topical therapies are less clear. Here we describe a case of severe refractory sino-orbital mucormycosis in an immunocompetent patient who responded to combination therapy with liposomal amphotericin, isavuconazole, micafungin, and topical amphotericin deoxycholate after failing to achieve negative surgical margins.

Comparison of β-D-Glucan levels between Candida auris and other Candida species at the time of candidaemia: a retrospective study

OBJECTIVES

To compare serum β-D-glucan (BDG) levels in candidaemia with different Candida species, especially C. auris.

METHODS

Aga Khan University clinical laboratory database was retrospectively reviewed from January 2015 to December 2019. Blood culture positive cases with any Candida species and concomitant BDG level were included.

RESULTS

Among the 192 cases included in our study, 48 were C. albicans, 54 C. auris, eight C. glabrata, 32 C. parapsilosis, 43 C. tropicalis and seven other Candida species. The level of BDG was significantly lower in C. auris (median 62.43, interquartile range (IQR) 12.80-182.94 pg/mL) compared to C. albicans (median 266.83, IQR 66.29-523.43 pg/mL) and C. tropicalis (median 324.41, IQR 105.20-523.44 pg/mL). The sensitivity of serum BDG was significantly lower for C. auris (43.75%, 95% CI 29.5-58.8%) than C. tropicalis (79.07%, 95% CI 64.0-90.0%).

DISCUSSION

Serum BDG has lower sensitivity in patients with suspected C. auris candidaemia in our setting. Considering that C. auris has higher morbidity and mortality than other species, a more sensitive test is required.

Galactomannan and 1, 3-β-D-Glucan Assay in Bronchoalveolar Lavage Fluid for the Diagnosis of Invasive Pulmonary Aspergillosis in Malignant and Non-malignant Patients

BACKGROUND: Serum 1, 3-β-D-glucan (BDG) assay was recommended for diagnosing fungal infections. AIM: We aimed to assess 1, 3-β-D-glucan in bronchoalveolar lavage (BAL) fluid in invasive pulmonary aspergillosis (IPA). METHODS: Out of 104 patients clinically suspected fungal, 45 were probable, 18 possible, and 41 unlikely according to EORTC/MSG 2008 criteria. Measuring BAL BDG and galactomannan were done. RESULTS: The sensitivity, specificity, and positive and negative predictive values (PPV and NPV) for BDG were 44%, 71%, 62%, and 54%; for galactomannan 84%, 83%, 84%, and 83%; and 93%, 66%, 75%, and 90%, respectively, when combining both tests. A significant different performance of GM; p = 0.0008 was detected in patients with malignant disorders when compared to non-malignant; but not for BDG; p = 0.121. CONCLUSION: We can conclude that BAL-BDG is helpful if positive in a clinically suspected IFI case, but if negative cannot rule out fungal infection. Thus, combining results of BAL-GM and BAL-BDG are recommended.

Low sensitivity of conventional fungal agars in fungemia by Rhodotorula mucilaginosa: description of two cases

Background

Although most bloodstream yeast infections are caused by Candida spp., infections by rare or less common species have increased in recent years. Diagnosis of infections caused by these species is difficult due to the lack of specific symptoms and adequate diagnostic tools.

Cases presentation

We describe two cases of fungemia by Rhodotorula mucilaginosa within a few months of each other, in a secondary Spanish hospital. In both cases, diagnosis was challenging. Blood subcultures in conventional fungal media were persistently negatives and the use of non-conventional fungal media was essential for isolating the yeasts and achieving a correct diagnosis. 1–3 beta-d-glucan detection and a panfungal PCR assay were helpful techniques to confirm the diagnosis

Conclusion

It is highly important to establish an early diagnosis for fungemia. The process is challenging because often non-specific symptoms are presents. When yeasts grow in blood cultures other genera than Candida spp. could be the cause of infection. Patient risk factors should be assessed to incorporate alternative culture media and the available rapid diagnostic test, in order to provide an early recognition of the pathogen.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-021-00427-w.

Clinical Relevance and Prognostic Value of Persistently Negative (1,3)-β-D-Glucan in Adults With Candidemia: A 5-year Experience in a Tertiary Hospital

BACKGROUND

The clinical relevance and the potential prognostic role of persistently negative (1,3)-β-D-glucan (BDG) in adults with proven candidemia is unknown.

METHODS

This retrospective study included all adults diagnosed with candidemia our tertiary university hospital from 2012-2017 who had at least 2 serum BDG determinations throughout the episode of fungemia (Fungitell Assay; positive cut-off ≥80pg/mL). Epidemiology and clinical outcomes were compared between patients with all negative versus any positive BDG tests. Poor clinical outcomes included complications due to candidemia or 30-day all-cause mortality.

RESULTS

Overall, 26/148 (17.6%) candidemic adults had persistently negative BDG tests. These patients were less likely to present Candida growth in all 3 sets of blood cultures (15.4% vs 45.1%; P = .005) and had less severe clinical presentations (median Pitt score, 0 [interquartile range {IQR} 0-1] vs 1 [IQR 0-2] in patients with any positive BDG test; P = .039). Although adequate treatment was equally provided to both groups (96.2% in persistently negative group vs 93.4 in positive group; P = .599), the persistently negative group had a higher rate of microbiological clearance in the first follow-up blood cultures (92.3% vs 69.7% in positive group; P = .005), fewer complications due to candidemia (7.7% vs 33.6% in positive group; P = .008), a lower 30-day mortality rate (3.8% vs 23.8% in positive group; P = .004), and a shorter in-hospital stay (34 days [IQR 18-55] vs 51 days [IQR 35-91] in positive group; P = .003). In the multivariate analysis, persistently negative BDG tests were independently associated with better prognoses (odds ratio 0.12, 95% confidence interval 0.03-0.49; P = .003).

CONCLUSIONS

Candidemic patients with persistently negative BDG tests present a better prognosis than the comparative group, probably due to a lower systemic fungal burden. In this context, the appropriate use of persistently negative BDG results could be an aid to individualize therapeutic management in the near future.

Johnson E, Littlechild J, Winlove CP, Vollmer F, Gow NAR. Biosensors and Diagnostics for Fungal Detection

Early detection is critical to the successful treatment of life-threatening infections caused by fungal pathogens, as late diagnosis of systemic infection almost always equates with a poor prognosis. The field of fungal diagnostics has some tests that are relatively simple, rapid to perform and are potentially suitable at the point of care. However, there are also more complex high-technology methodologies that offer new opportunities regarding the scale and precision of fungal diagnosis, but may be more limited in their portability and affordability. Future developments in this field are increasingly incorporating new technologies provided by the use of new format biosensors. This overview provides a critical review of current fungal diagnostics and the development of new biophysical technologies that are being applied for selective new sensitive fungal biosensors to augment traditional diagnostic methodologies.

Clinical evaluation of two different (1,3)-ß-d-glucan assays for diagnosis of invasive fungal diseases: A retrospective cohort study

BACKGROUND

Early diagnosis of invasive fungal diseases (IFDs) remains a major challenge in routine clinical practice.

OBJECTIVES

The aim of this retrospective cohort study was to evaluate the diagnostic performance of the fungal biomarker (1,3)-ß-d-glucan (BDG) using the β-Glucan test (GT) and the well-established Fungitell assay® (FA) in real-life clinical practice.

PATIENTS/METHODS

We included 109 patients with clinical suspicion of IFD who were treated at Jena University Hospital, Germany, between November 2018 and March 2019. The patients were classified according to the latest update of the EORTC/MSG consensus definitions of IFD. The first serum sample of every patient was analysed for BDG using the FA and the GT, respectively.

RESULTS

Fifty-six patients (51.4%) had at least one host factor for IFD. In patients with proven (n = 11) or probable IFDs (n = 20), median BDG concentrations were 145.0 pg/ml for the FA and 5.1 pg/ml for the GT, respectively. A positive test result of both BDG assays at manufacturer's cut-offs predicted 89.5%-98.3% of proven or probable IFD, but the sensitivity of both assays was limited: The FA identified 60.7% of IFDs (cut-off: 80 pg/ml). Reducing the GT cut-off value from 11.0 to 4.1 pg/ml increased the detection rate of IFDs from 35.5% to 54.8%.

CONCLUSIONS

A positive test result of both BDG assays at manufacturer's cut-off was highly predictive for IFD, but except for Pneumocystis jirovecii pneumonia sensitivities were limited. Adjustment of the GT cut-off value equalised sensitivities of GT and FA.

Scedosporium Cell Wall: From Carbohydrate-Containing Structures to Host-Pathogen Interactions

Scedosporium species are filamentous fungi usually found in sewage and soil from human-impacted areas. They cause a wide range of diseases in humans, from superficial infections, such as mycetoma, to invasive and disseminated cases, especially associated in immunocompromised patients. Scedosporium species are also related to lung colonization in individuals presenting cystic fibrosis and are considered one of the most frequent fungal pathogens associated to this pathology. Scedosporium cell wall contains glycosylated molecules involved in important biological events related to virulence and pathogenicity and represents a significant source of antigens. Polysaccharides, peptidopolysaccharides, O-linked oligosaccharides and glycosphingolipids have been identified on the Scedosporium surface. Their primary structures were determined based on a combination of techniques including gas chromatography, ESI-MS, and ¹H and ¹³C nuclear magnetic resonance. Peptidorhamnnomannans are common cell wall components among Scedosporium species. Comparing different species, minor structural differences in the carbohydrate portions were detected which could be useful to understand variations in virulence observed among the species. N- and O-linked peptidorhamnomannans are major pathogen-associated molecular patterns and, along with α-glucans, play important roles in triggering host innate immunity. Glycosphingolipids, such as glucosylceramides, have highly conserved structures in Scedosporium species and are crucial for fungal growth and virulence. The present review presents current knowledge on structural and functional aspects of Scedosporium glycoconjugates that are relevant for understanding pathogenicity mechanisms and could contribute to the design of new agents capable of inhibiting growth and differentiation of Scedosporium species. Other cell components such as melanin and ectophosphatases will be also included.

Current knowledge on the etiology and epidemiology of Scopulariopsis infections

Scopulariopsis is a common fungus in the environment, characterized by its intrinsic resistance to the available antifungal drugs. Around 70 cases of infection by this fungus have been described in the literature. Pulmonary and disseminated infections are the most common and their treatment is difficult; therefore, very diverse approaches have been taken, with varied results. A successful outcome has been reported in only a few cases, generally attributed to a multitreatment strategy combining medical and surgical procedures that ultimately led to the resection of the infected tissue if possible, identification of the mould, and an aggressive long-term antifungal therapy. Although most of the infections are caused by Scopulariopsis brevicaulis, a few other species have also been linked to these cases, although molecular evidence has not been proven for all of them. On this basis, more knowledge on the epidemiology, presentation, diagnosis, treatment, and prognosis of these unusual infections would improve their management. This review aims to compile the current data on Scopulariopsis infections.

Radioimmunotherapy of Blastomycosis in a Mouse Model With a (1→3)-β-Glucans Targeting Antibody

Invasive fungal infections (IFI) cause devastating morbidity and mortality, with the number of IFIs more than tripling since 1979. Our laboratories were the first to demonstrate that radiolabeled microorganism-specific monoclonal antibodies are highly effective for treatment of experimental fungal, bacterial and viral infections. Later we proposed to utilize surface expressed pan-antigens shared by major IFI-causing pathogens such as beta-glucans as RIT targets. Here we evaluated in vivo RIT targeting beta-glucan in Blastomyces dermatitidis which causes serious infections in immunocompromised and immunocompetent individuals and in companion dogs. B. dermatitidis cells were treated with the 400-2 antibody to (1→3)-β-glucans radiolabeled with the beta-emitter 177Lutetium (¹⁷⁷Lu) and alpha-emitter 213Bismuth (²¹³Bi) and the efficacy of cell kill was determined by colony forming units (CFUs). To determine the antigen-specific localization of the 400-2 antibody in vivo, C57BL6 mice were infected intratracheally with 2 × 10⁵B. dermatitidis cells and given ¹¹¹In-400-2 antibody 24 h later. To evaluate the killing of B. dermatitidis cells with RIT, intratracheally infected mice were treated with 150 μCi ²¹³Bi-400-2 and their lungs analyzed for CFUs 96 h post-infection. ²¹³Bi-400-2 proved to be more effective in killing B. dermatitidis cells in vitro than ¹⁷⁷Lu-400-2. Three times more ¹¹¹In-400-2 accumulated in the lungs of infected mice, than in the non-infected ones. ²¹³Bi-400-2 lowered the fungal burden in the lungs of infected mice more than 2 logs in comparison with non-treated infected controls. In conclusion, our results demonstrate the ability of an anti-(1-3)-beta-D-glucan antibody armed with an alpha-emitter ²¹³Bi to selectively kill B. dermatitidis cells in vitro and in vivo. These first in vivo results of the effectiveness of RIT targeting pan-antigens on fungal pathogens warrant further investigation.

Fungal Infections of the Stem Cell Transplant Recipient and Hematologic Malignancy Patients

Despite advances in chemotherapy and supportive care, morbidity and mortality remain high for patients with hematologic malignancies (HMs). Those who require hematopoietic stem cell transplantation (HSCT) often require significant immunosuppression and are subject to a variety of complications. These patients carry multiple risk factors for infectious complications, including the development of invasive fungal infections, compared with the general population. Because antifungal prophylaxis has been widely adopted, there has been a shift away from invasive candidiasis toward invasive mold infections, including breakthrough infections. For patients with HM and HSCT, we outline the epidemiology, manifestations, diagnosis, and treatment of invasive fungal infections.

Clinical characteristics and prognoses of pulmonary mucormycosis in four children

IMPORTANCE

Pulmonary mucormycosis is life threatening and carries a poor prognosis. Identification of factors that improve prognosis is urgently necessary.

OBJECTIVE

To analyze the clinical features and outcomes of pulmonary mucormycosis in children.

METHODS

A retrospective analysis of clinical data of four cases with pulmonary mucormycosis was conducted in Beijing Children's Hospital from January 2017 to December 2018.

RESULTS

Underlying diseases were identified in all four cases (diabetes in three individuals and a hematological malignancy in one individual). The predominant clinical manifestations were fever, cough, chest pain and hemoptysis. Imaging features included consolidation or nodules with cavities. All four cases were treated with liposomal amphotericin B, one case underwent lobectomy, and three cases received a full course of posaconazole. All four cases were cured.

INTERPRETATION

Patients with pulmonary mucormycosis often have underlying diseases. Imaging features are relatively characteristic. Treatment with liposomal amphotericin B at an early stage and a sufficient course of posaconazole for maintenance significantly improves prognosis.

Saprochaete clavata Invasive Infections - A New Threat to Hematological-Oncological Patients

Background

Saprochaete clavata (formerly Geotrichum clavatum, now proposed as Magnusiomyces clavatus) is a filamentous yeast-like fungus that has recently been described as an emerging pathogen mostly in patients with acute leukemia.

Methods

This is a retrospective study of patients diagnosed with proven and probable S. clavata infection at the University Hospital, Hradec Králové, Czechia between March 2005 and December 2017. Previous cases were identified from the literature and FungiScope^® database.

Results

Six new cases (5 females, 1 male) of blood-stream S. clavata infections at the hemato-oncological department were described including epidemiological data of additional 48 patients colonized with the species. Overall, 116 strains of S. clavata were isolated from different clinical specimens of 54 patients; most of them belonged to the respiratory tract (60.3%). S. clavata was the most frequent species among arthroconidial yeasts (Trichosporon, Galactomyces, Magnusiomyces) recovered from the blood. All our patients with S. clavata infection had profound neutropenia, a central venous catheter, broad-spectrum antibiotics and antifungal prophylaxis; four had a history of a biliary tract system disease. The diagnosis was based on a positive blood culture in all patients. Four patients died of multiorgan failure and sepsis despite treatment with lipid-based amphotericin B and/or voriconazole. From the literature and FungiScope database, 67 previous cases of S. clavata infections were evaluated in context of our cases.

Conclusion

Saprochaete clavata infection represents a life-threatening mycosis in severely immunocompromised patients. The successful outcome of treatment seems to be critically dependent on the early diagnosis and the recovery of underlying conditions associated with immune dysfunction or deficiency.

Saprochaete clavata infections in patients undergoing treatment for haematological malignancies: A report of a monocentric outbreak and review of the literature

Saprochaete clavata is a rare cause of fungaemia with deep organ involvement in patients with haematological malignancies with reported mortality rates of 60%-80%. We describe four cases of S clavata infection in a haematology unit over several months that were treated with voriconazole-based regimens. We also review the literature on factors that could contribute to earlier recognition and effective treatment of S clavata. We included all cases of culture-positive S clavata from sterile sites with associated signs of infection in patients undergoing treatment for a haematological malignancy. Isolates were identified by MALDI-TOF MS, and spectrum profiles were used to prepare clustering analysis of isolates. Susceptibility testing was performed using a commercial microtitre methods. Saprochaete clavata was isolated from the bloodstream in three cases and bronchial alveolar lavage (BAL) fluid in one case. Clustering analysis suggested strains of S clavata were clonal without evidence of divergence although a common source was not identified. Susceptibility testing yielded elevated MICs to fluconazole (8 mg/L) and echinocandins (>1-8 mg/L). All patients were treated with voriconazole-based regimens resulting in survival of 3/4 patients, who continued chemotherapy for their underlying malignancy without evidence of relapse. Saprochaete clavata is a rare but aggressive cause of breakthrough yeast infection in patients undergoing treatment for haematological malignancies, particularly patients with a prior history of echinocandin treatment. Timely initiation of appropriate treatment, aided by more rapid identification in microbiology laboratory, can reduce the risk of deep organ dissemination and patient death.

Evaluation of biomarkers: Galactomannan and 1,3-beta-D-glucan assay for the diagnosis of invasive fungal infections in immunocompromised patients from a tertiary care centre

Purpose

Due to limitations of traditional microbiological techniques, standardised fungal biomarker tests such as Galactomannan Index (GMI) and 1,3-beta-D-glucan (BDG) are being preferred for diagnosis of invasive fungal infections (IFIs). These tests have been extensively used in developed countries but seldom in developing countries. The present study was performed to evaluate these tests for the diagnosis of IFIs in immunocompromised patients at an Indian tertiary care centre.

Materials and Methods

A retrospective hospital-based study was done in immunocompromised patients with clinical suspicion of IFI. The demographic, clinical, radiological and mycological details of the patients were recorded. The patients were categorised into proven, probable and no IFI (as per European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria). The sensitivity and specificity of BDG Fungitell and Platelia Aspergillus antigen assays was estimated.

Results

A total of 70 consecutive patients were included, of which 41 had IFI (10 proven and 31 probable) while 29 had no IFI. A significant association was found between IFI and the presence of a central venous line (P = 0.035) and history of intake of T-cell immunosuppressants (P = 0.001). Median BDG values (pg/ml) in patients with proven IFI, probable IFI and no IFI were 300 (range: 70-500), 165 (range: 53-500) and 45 (range: 31-500), respectively. The receiver operating characteristic (ROC) curve analysis for BDG revealed an area under the curve of 0.995, sensitivity: 97.4% and specificity: 96.6% for IFI diagnosis. The ROC curve analysis of GMI revealed an AUC of 0.75 and 90% patients with invasive aspergillosis (IA) had positive GMI.

Conclusion

BDG has good sensitivity and specificity for distinguishing IFI from no IFIs and GMI may be used for diagnosing IA.

New Concepts in Diagnostics for Invasive Mycoses: Non-Culture-Based Methodologies

Non-culture-based diagnostics have been developed to help establish an early diagnosis of invasive fungal infection. Studies have shown that these tests can significantly impact the diagnosis of infection in high risk patients. Aspergillus galactomannan EIA testing is well-recognized as an important adjunct to the diagnosis of invasive aspergillosis and can be detected in serum, bronchoalveolar lavage and other fluids. Galactomannan testing used along with PCR testing has been shown to be effective when integrated into care paths for high risk patients for both diagnoses and as a surrogate marker for outcome when used in serial testing. Beta-d-glucan assays are non-specific for several fungal genera including Aspergillus and Candida and in high risk patients have been an important tool to augment the diagnosis. Lateral flow technology using monoclonal antibodies to Aspergillus are available that allow rapid testing of clinical samples. While standard PCR for Candida remains investigational, T2 magnetic resonance allows for the rapid diagnosis of Candida species from blood cultures. Aspergillus PCR has been extensively validated with standardized approaches established for these methods and will be included in the diagnostic criteria in the revised European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC-MSG) definitions. Finally, these non-culture-based tests can be used in combination to significantly increase the detection of invasive mycoses with the ultimate aim of establishing an early diagnosis of infection.

Scedosporium and Lomentospora: an updated overview of underrated opportunists

Species of Scedosporium and Lomentospora are considered as emerging opportunists, affecting immunosuppressed and otherwise debilitated patients, although classically they are known from causing trauma-associated infections in healthy individuals. Clinical manifestations range from local infection to pulmonary colonization and severe invasive disease, in which mortality rates may be over 80%. These unacceptably high rates are due to the clinical status of patients, diagnostic difficulties, and to intrinsic antifungal resistance of these fungi. In consequence, several consortia have been founded to increase research efforts on these orphan fungi. The current review presents recent findings and summarizes the most relevant points, including the Scedosporium/Lomentospora taxonomy, environmental distribution, epidemiology, pathology, virulence factors, immunology, diagnostic methods, and therapeutic strategies.

False-positive elevation of 1,3-beta-D-glucan caused by continuous administration of penicillin G

The 1,3-beta-D-Glucan (BDG) assay is widely used for the diagnosis of fungal infections, especially in patients with hematologic malignancies. Some antimicrobials have been reported to cause false-positive results for BDG, but there has been no report on the effect of penicillin G (PCG) on BDG levels. We experienced a patient who developed false-positive BDG elevation during the administration of PCG for osteomyelitis due to Streptococcus pneumoniae infection. The serum BDG level increased up to 81.0 pg/ml during the continuous administration of PCG at 24 million units per day. However, chest and paranasal CT scan showed no evidence of fungal infection. The BDG level decreased to 38.0 pg/ml at 14 hours after the discontinuation of PCG. The amount of BDG in one vial of PCG inferred from these serum BDG levels is very similar to the actual BDG concentration in a vial of PCG. Therefore, during the administration of PCG, elevated BDG levels should be interpreted with caution, as they may be false-positive results.

Invasive Scopulariopsis alboflavescens infection in patient with acute myeloid leukemia

Scopulariopsis alboflavescens is a soil saprophyte that is widely distributed in nature. Recently, there have been increasing number of reports of invasive infections with Scopulariopsis species in immunocompromised patients. In this report, we described an adult woman with acute myeloid leukemia and who developed S. alboflavescens pneumonia. Liposomal amphotericin B and voriconazole combination therapy was unsuccessful and the patient died because of pneumonia. Scopulariopsis is highly resistant to available antifungal agents and almost invariably fatal. This case report should alert clinicians to the importance of listing Scopulariopsis as a pathogenic fungus in immunocompromised patients.

Antifungal Activity of Plasmacytoid Dendritic Cells and the Impact of Chronic HIV Infection

Due to the effectiveness of combined antiretroviral therapy, people living with HIV can control viral replication and live longer lifespans than ever. However, HIV-positive individuals still face challenges to their health and well-being, including dysregulation of the immune system resulting from years of chronic immune activation, as well as opportunistic infections from pathogenic fungi. This review focuses on one of the key players in HIV immunology, the plasmacytoid dendritic cell (pDC), which links the innate and adaptive immune response and is notable for being the body’s most potent producer of type-I interferons (IFNs). During chronic HIV infection, the pDC compartment is greatly dysregulated, experiencing a substantial depletion in number and compromise in function. This immune dysregulation may leave patients further susceptible to opportunistic infections. This is especially important when considering a new role for pDCs currently emerging in the literature: in addition to their role in antiviral immunity, recent studies suggest that pDCs also play an important role in antifungal immunity. Supporting this new role, pDCs express C-type lectin receptors including dectin-1, dectin-2, dectin-3, and mannose receptor, and toll-like receptors-4 and -9 that are involved in recognition, signaling, and response to a wide variety of fungal pathogens, including Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, and Pneumocystis jirovecii. Accordingly, pDCs have been demonstrated to recognize and respond to certain pathogenic fungi, measured via activation, cytokine production, and fungistatic activity in vitro, while in vivo mouse models indicated a strikingly vital role for pDCs in survival against pulmonary Aspergillus challenge. Here, we discuss the role of the pDC compartment and the dysregulation it undergoes during chronic HIV infection, as well as what is known so far about the role and mechanisms of pDC antifungal activity.

Use of 1,3-β-D-glucan in invasive fungal diseases in hematology patients

INTRODUCTION

Invasive fungal diseases (IFD) remain a leading cause of morbidity and mortality in hematology patients. Within a diagnostic-driven approach, the use of the serum (1,3)-ß-D-glucan (BDG) test represents a valid tool for the early diagnosis and treatment of IFD. Areas covered: The available literature on the use of BDG in hematology patients was systematically retrieved. Then, it was reviewed and discussed, to identify key issues pertaining to a clinically-oriented narrative presentation of the topic. Expert commentary: The use of BDG in hematology patients at risk for invasive aspergillosis (IA) is secondary to the use of galactomannan. However, since BDG is not specific for IA, it offers an advantage of diagnosing also other IFD, such as candidiasis and pneumocystosis. The limitations of BDG include high costs and lower sensitivity in hematology patients compared to other cohorts. The risk of false positive results is possibly lower in real life than in theory, since glucan-free equipment is available and modern dialysis membranes and blood products usually do not release BDG. Thus, in experienced hands and selected clinical situations, BDG is a useful diagnostic tool, particularly due to short turnover time to results and versatility in diagnosing different IFD.

Rare fungal infectious agents: a lurking enemy

In the expanding population of immunocompromised patients and those treated in intensive care units, rare fungal infectious agents have emerged as important pathogens, causing invasive infections associated with high morbidity and mortality. These infections may present either as de novo or as breakthrough invasive infections in high-risk patients with hematologic malignancies receiving prophylactic or empirical antifungal therapy or in patients with central venous catheters. Diagnosis and treatment are challenging. Physicians should have a high index of suspicion because early diagnosis is of paramount importance. Conventional diagnostic methods such as cultures and histopathology are still essential, but rapid and more specific molecular techniques for both detection and identification of the infecting pathogens are being developed and hopefully will lead to early targeted treatment. The management of invasive fungal infections is multimodal. Reversal of risk factors, if feasible, should be attempted. Surgical debridement is recommended in localized mold infections. The efficacy of various antifungal drugs is not uniform. Amphotericin B is active against most yeasts, except Trichosporon, as well as against Mucorales, Fusarium, and some species of Paecilomyces and dimorphic fungi. The use of voriconazole is suggested for the treatment of trichosporonosis and scedosporiosis. Combination treatment, though recommended as salvage therapy in some infections, is controversial in most cases. Despite the use of available antifungals, mortality remains high. The optimization of molecular-based techniques, with expansion of reference libraries and the possibility for direct detection of resistance mechanisms, is awaited with great interest in the near future. Further research is necessary, however, in order to find the best ways to confront and destroy these lurking enemies.

Intestinal Fungal Dysbiosis Is Associated With Visceral Hypersensitivity in Patients With Irritable Bowel Syndrome and Rats

BACKGROUND & AIMS

Visceral hypersensitivity is one feature of irritable bowel syndrome (IBS). Bacterial dysbiosis might be involved in the activation of nociceptive sensory pathways, but there have been few studies of the role of the mycobiome (the fungal microbiome) in the development of IBS. We analyzed intestinal mycobiomes of patients with IBS and a rat model of visceral hypersensitivity.

METHODS

We used internal transcribed spacer 1-based metabarcoding to compare fecal mycobiomes of 18 healthy volunteers with those of 39 patients with IBS (with visceral hypersensitivity or normal levels of sensitivity). We also compared the mycobiomes of Long-Evans rats separated from their mothers (hypersensitive) with non-handled (normally sensitive) rats. We investigated whether fungi can cause visceral hypersensitivity using rats exposed to fungicide (fluconazole and nystatin). The functional relevance of the gut mycobiome was confirmed in fecal transplantation experiments: adult maternally separated rats were subjected to water avoidance stress (to induce visceral hypersensitivity), then given fungicide and donor cecum content via oral gavage. Other rats subjected to water avoidance stress were given soluble β-glucans, which antagonize C-type lectin domain family 7 member A (CLEC7A or DECTIN1) signaling via spleen-associated tyrosine kinase (SYK), a SYK inhibitor to reduce visceral hypersensitivity, or vehicle (control). The sensitivity of mast cells to fungi was tested with mesenteric windows (ex vivo) and the human mast cell line HMC-1.

RESULTS

α diversity (Shannon index) and mycobiome signature (stability selection) of both groups of IBS patients differed from healthy volunteers, and the mycobiome signature of hypersensitive patients differed from that of normally sensitive patients. We observed mycobiome dysbiosis in rats that had been separated from their mothers compared with non-handled rats. Administration of fungicide to hypersensitive rats reduced their visceral hypersensitivity to normal levels of sensitivity. Administration of cecal mycobiomes from rats that had been separated from their mothers (but not non-handled mycobiome) restored hypersensitivity to distension. Administration of soluble β-glucans or a SYK inhibitor reduced visceral hypersensitivity, compared with controls. Particulate β-glucan (a DECTIN-1 agonist) induced mast cell degranulation in mesenteric windows and HMC-1 cells responded to fungal antigens by release of histamine.

CONCLUSIONS

In an analysis of patients with IBS and controls, we associated fungal dysbiosis with IBS. In studies of rats, we found fungi to promote visceral hypersensitivity, which could be reduced by administration of fungicides, soluble β-glucans, or a SYK inhibitor. The intestinal fungi might therefore be manipulated for treatment of IBS-related visceral hypersensitivity.

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.

Emergence of the Molds Other than Aspergillus in Immunocompromised Patients

Immunocompromised patients are at high risk for invasive fungal infections (IFIs); although Aspergillus remains the most common IFI caused by molds, other fungi, such as Mucorales, dematiaceous molds, and Fusarium spp, are being seen with increasing frequency. Presentations can vary, but sinopulmonary and disseminated infections are common. Our understanding of the pathogenesis of these infections is rudimentary. Fungal cultures and histopathology remain the backbone of diagnostics, as no good serologic markers are available. Polymerase chain reaction tests are being developed but currently remain investigational. Management of these infections is usually multidisciplinary, requiring surgical debridement along with antifungal therapy.

[Validation of a New (1 → 3)-β-D-Glucan Test Kit, Fungitec G Test MKⅡ " Nissui "]

Using 415 residual blood samples subjected to (1→3) -β-D-glucan assay, we studied the correlation of measurement results between Fungitec G Test MKII "Nissui" (Nissui Pharmaceutical Co., Ltd., Tokyo) and its predecessor, Fungitec G Test MK (Seikagaku Corporation, Tokyo), which is now out of production. Their major difference is that MK II uses reagents derived from blood cells of Limulus polyphemus, the American horseshoe crab, whereas MK used those of Tachypleus tridentatus, an Asian horseshoe crab. Passing-Bablok analysis showed a linear regression with nearly one-to-one correspondence (slope=1.065, intercept=-0.287) between the two test kits over the regular range of measurements (4.0 pg/ml -500 pg/ml ). This was also true when data were subdivided and analyzed in the low to medium (≦150 pg/ml ) and in the low range (≦50 pg/ml ). There were several cases, however, that showed a wide discrepancy between the pair of measurements. This discrepancy is believed to be due in part to the difference between Limulus and Tachypleus in their reactivity to β-glucans with diverse side chains. Despite of this, the even distribution on either side of the regression line of those samples that are associated with deep fungal infection and the abrupt disappearance of such samples below 20 pg/ml attest that MK II "Nissui" is an acceptable successor of MK.

Application of the 1,3-β-D-Glucan (Fungitell) Assay in the Diagnosis of Invasive Fungal Infections

With the high mortality rate associated with invasive fungal infections, methods for timely detection and diagnosis are necessary for appropriate and effective treatment. Testing for 1,3-β-D-glucan, a cell wall component of many medically important fungi, can be a useful adjunct in diagnosing such infections. The Fungitell assay (Associates of Cape Cod, East Falmouth, Massachusetts) is a US Food and Drug Administration-approved laboratory test that quantitatively measures 1,3-β-D-glucan levels and is widely available for clinical use as a relatively noninvasive method to aid in detecting the presence of invasive fungal infections. Numerous studies have evaluated its performance in clinical settings, and results have, overall, been favorable. It is not without its drawbacks, however, and the test must be interpreted and applied with care. Ordering practices are also widely variable among clinicians, and official guidelines have not been readily available. We present the details of this test and aim to propose evidence-based guidance for its use.