Invasive aspergillosis: epidemiology, diagnosis and management in immunocompromised patients

Contemporary Gene Flow is a Major Force Shaping the Aspergillus fumigatus Population in Auckland, New Zealand

Aspergillus fumigatus is a globally distributed opportunistic fungal pathogen capable of causing highly lethal invasive aspergillosis in immunocompromised individuals. Recent studies have indicated that the global population consists of multiple, divergent genetic clusters that are geographically broadly distributed. However, most of the analyzed samples have come from continental Eurasia and the Americas where the effects of ancient versus recent factors are difficult to distinguish. Here, we investigated environmental A. fumigatus isolates from Auckland, New Zealand, a geographically isolated population, and compared them with those from other parts of the world to determine the relative roles of historical differentiation and recent gene flow in shaping A. fumigatus populations. Our data suggest that the Auckland A. fumigatus population contains both unique indigenous genetic elements as well as genetic elements that are similar to those from other regions such as Europe, Africa, and North America. Though the hypothesis of random recombination was rejected, we found abundant evidence for phylogenetic incompatibility and recombination within the Auckland A. fumigatus population. Additionally, susceptibility testing identified two triazole-resistant strains, one of which contained the globally distributed mutation TR₃₄/L98H in the cyp51A gene. Our results suggest that contemporary gene flow, likely due to anthropogenic factors, is a major force shaping the New Zealand A. fumigatus population.

High Efficiency Drug Repurposing Design for New Antifungal Agents

Current antifungal interventions have often limited efficiency in treating fungal pathogens, particularly those resistant to commercial drugs or fungicides. Antifungal drug repurposing is an alternative intervention strategy, whereby new utility of various marketed, non-antifungal drugs could be repositioned as novel antifungal agents. In this study, we investigated “chemosensitization” as a method to improve the efficiency of antifungal drug repurposing, wherein combined application of a second compound (viz., chemosensitizer) with a conventional, non-antifungal drug could greatly enhance the antifungal activity of the co-applied drug. Redox-active natural compounds or structural derivatives, such as thymol (2-isopropyl-5-methylphenol), 4-isopropyl-3-methylphenol, or 3,5-dimethoxybenzaldehyde, could serve as potent chemosensitizers to enhance antifungal activity of the repurposed drug bithionol. Of note, inclusion of fungal mutants, such as antioxidant mutants, could also facilitate drug repurposing efficiency, which is reflected in the enhancement of antifungal efficacy of bithionol. Bithionol overcame antifungal (viz., fludioxonil) tolerance of the antioxidant mutants of the human/animal pathogen Aspergillus fumigatus. Altogether, our strategy can lead to the development of a high efficiency drug repurposing design, which enhances the susceptibility of pathogens to drugs, reduces time and costs for new antifungal development, and abates drug or fungicide resistance.

Intracellular Delivery of Biologically-Active Fungal Metabolite Gliotoxin Using Magnetic Nanoparticles

Gliotoxin (GT), a secondary metabolite produced by Aspergillus molds, has been proposed as a potential anti-tumor agent. Here we have developed a nanoparticle approach to enhance delivery of GT in tumor cells and establish a basis for its potential use as therapeutical drug. GT bound to magnetic nanoparticles (MNPs) retained a high anti-tumor activity, correlating with efficient intracellular delivery, which was increased in the presence of glucose. Our results show that the attachment of GT to MNPs by covalent bonding enhances intracellular GT delivery without affecting its biological activity. This finding represents the first step to use this potent anti-tumor agent in the treatment of cancer.

Clinical mycology in Latin America and the Caribbean: A snapshot of diagnostic and therapeutic capabilities

Despite the existence of endemic mycoses in Latin America and the Caribbean, in addition to a large population of patients at risk for invasive mycoses, the capability of medical centres to perform a proper diagnosis in mycology has not been studied in the region. Moreover, availability of antifungal drugs in the region is unknown. Here, we report the results of a survey involving 129 centres in 24 countries. Only 9% of centres would have the potential to apply for the minimum standards in mycology, as determined by the European Confederation of Medical Mycology. There is an urgent need to improve diagnostic conditions in Latin America and the Caribbean, as well as providing access to safer and more efficacious antifungal drugs.

Azole-resistant and -susceptible Aspergillus fumigatus isolates show comparable fitness and azole treatment outcome in immunocompetent mice

No data are available on the in vivo impact of infections with in vitro azole-resistant Aspergillus fumigatus in immunocompetent hosts. Here, the aim was to investigate fungal fitness and treatment response in immunocompetent mice infected with A. fumigatus (parental strain [ps]) and isogenic mutants carrying either the mutation M220K or G54W (cyp51A). The efficacy of itraconazole (ITC) and posaconazole (PSC) was investigated in mice, intravenously challenged either with a single or a combination of ps and mutants (6 × 105 conidia/mouse). Organ fungal burden and clinical parameters were measured. In coinfection models, no fitness advantage was observed for the ps strain when compared to the mutants (M220K and G54W) independent of the presence or absence of azole-treatment. For G54W, M220K, and the ps, no statistically significant difference in ITC and PSC treatment was observed in respect to fungal kidney burden. However, clinical parameters suggest that in particular the azole-resistant strain carrying the mutation G54W caused a more severe disease than the ps strain. Mice infected with G54W showed a significant decline in body weight and lymphocyte counts, while spleen/body weight ratio and granulocyte counts were increased. In immunocompetent mice, in vitro azole-resistance did not translate into therapeutic failure by either ITC or PSC; the immune system appears to play the key role in clearing the infection.

A Prospective Real-World Study of the Impact of an Antifungal Stewardship Program in a Tertiary Respiratory-Medicine Setting

There has been an increase in fungal infections in patients with chronic lung disease over the past decades, which is associated with rapidly increasing costs to health care systems. An antifungal stewardship team was introduced to a tertiary cardiopulmonary hospital, consisting of a medical mycologist and pharmacy support providing weekly stewardship ward rounds, twice-monthly multidisciplinary team meetings, and a dedicated weekly outpatient clinic. A database was set up to record the activity of the stewardship team. During the first 18 months of implementation, the antifungal stewardship team had reviewed 178 patients, with 285 recommendations made to inpatients, and 287 outpatient visits. The commonest diagnoses treated were allergic bronchopulmonary aspergillosis and chronic pulmonary aspergillosis. Cystic fibrosis was the largest patient group treated, followed by asthma and interstitial lung disease. There was a significant sustained reduction in monthly antifungal expenditure (P = 0.005) by £130,000 per month. There was also a significant reduction in antifungal use, measured as the defined daily dose/100 bed days (P = 0.017). There were no significant changes in expenditure on diagnostic tests. There has been a trend toward more patients having therapeutic levels of voriconazole (P = 0.086) and a significant increase in therapeutic levels of posaconazole (P < 0.0001). This study shows that an effective antifungal stewardship program can significantly reduce expenditure in a specialist respiratory service.

The Collaborative Cross mouse model for dissecting genetic susceptibility to infectious diseases

Infectious diseases, also known as communicable diseases, refer to a full range of maladies caused by pathogen invasion to the host body. Host response towards an infectious pathogen varies between individuals, and can be defined by responses from asymptomatic to lethal. Host response to infectious pathogens is considered as a complex trait controlled by gene-gene (host-pathogen) and gene-environment interactions, leading to the extensive phenotypic variations between individuals. With the advancement of the human genome mapping approaches and tools, various genome-wide association studies (GWAS) were performed, aimed at mapping the genetic basis underlying host susceptibility towards infectious pathogens. In parallel, immense efforts were invested in enhancing the genetic mapping resolution and gene-cloning efficacy, using advanced mouse models including advanced intercross lines; outbred populations; consomic, congenic; and recombinant inbred lines. Notwithstanding the evident advances achieved using these mouse models, the genetic diversity was low and quantitative trait loci (QTL) mapping resolution was inadequate. Consequently, the Collaborative Cross (CC) mouse model was established by full-reciprocal mating of eight divergent founder strains of mice (A/J, C57BL/6J, 129S1/SvImJ, NOD/LtJ, NZO/HiLtJ, CAST/Ei, PWK/PhJ, and WSB/EiJ) generating a next-generation mouse genetic reference population (CC lines). Presently, the CC mouse model population comprises a set of about 200 recombinant inbred CC lines exhibiting a unique high genetic diversity and which are accessible for multidisciplinary studies. The CC mouse model efficacy was validated by various studies in our lab and others, accomplishing high-resolution (< 1 MB) QTL genomic mapping for a variety of complex traits, using about 50 CC lines (3-4 mice per line). Herein, we present a number of studies demonstrating the power of the CC mouse model, which has been utilized in our lab for mapping the genetic basis of host susceptibility to various infectious pathogens. These include Aspergillus fumigatus, Klebsiella pneumoniae, Porphyromonas gingivalis and Fusobacterium nucleatum (causing oral mixed infection), Pseudomonas aeruginosa, and the bacterial toxins Lipopolysaccharide and Lipoteichoic acid.

Additional oxidative stress reroutes the global response of Aspergillus fumigatus to iron depletion

BACKGROUND

Aspergillus fumigatus has to cope with a combination of several stress types while colonizing the human body. A functional interplay between these different stress responses can increase the chances of survival for this opportunistic human pathogen during the invasion of its host. In this study, we shed light on how the H2O2-induced oxidative stress response depends on the iron available to this filamentous fungus, using transcriptomic analysis, proteomic profiles, and growth assays.

RESULTS

The applied H2O2 treatment, which induced only a negligible stress response in iron-replete cultures, deleteriously affected the fungus under iron deprivation. The majority of stress-induced changes in gene and protein expression was not predictable from data coming from individual stress exposure and was only characteristic for the combination of oxidative stress plus iron deprivation. Our experimental data suggest that the physiological effects of combined stresses and the survival of the fungus highly depend on fragile balances between economization of iron and production of essential iron-containing proteins. One observed strategy was the overproduction of iron-independent antioxidant proteins to combat oxidative stress during iron deprivation, e.g. the upregulation of superoxide dismutase Sod1, the thioredoxin reductase Trr1, and the thioredoxin orthologue Afu5g11320. On the other hand, oxidative stress induction overruled iron deprivation-mediated repression of several genes. In agreement with the gene expression data, growth studies underlined that in A. fumigatus iron deprivation aggravates oxidative stress susceptibility.

CONCLUSIONS

Our data demonstrate that studying stress responses under separate single stress conditions is not sufficient to understand how A. fumigatus adapts in a complex and hostile habitat like the human body. The combinatorial stress of iron depletion and hydrogen peroxide caused clear non-additive effects upon the stress response of A. fumigatus. Our data further supported the view that the ability of A. fumigatus to cause diseases in humans strongly depends on its fitness attributes and less on specific virulence factors. In summary, A. fumigatus is able to mount and coordinate complex and efficient responses to combined stresses like iron deprivation plus H2O2-induced oxidative stress, which are exploited by immune cells to kill fungal pathogens.

DNA Barcoding Coupled with High Resolution Melting Analysis Enables Rapid and Accurate Distinction of Aspergillus species

We describe a high-resolution melting (HRM) analysis method that is rapid, reproducible, and able to identify reference strains and further 40 clinical isolates of Aspergillus fumigatus (14), A. lentulus (3), A. terreus (7), A. flavus (8), A. niger (2), A. welwitschiae (4), and A. tubingensis (2). Asp1 and Asp2 primer sets were designed to amplify partial sequences of the Aspergillus benA (beta-tubulin) genes in a closed-, single-tube system. Human placenta DNA, further Aspergillus (3), Candida (9), Fusarium (6), and Scedosporium (2) nucleic acids from type strains and clinical isolates were also included in this study to evaluate cross reactivity with other relevant pathogens causing invasive fungal infections. The barcoding capacity of this method proved to be 100% providing distinctive binomial scores; 14, 34, 36, 35, 25, 15, 26 when tested among species, while the within-species distinction capacity of the assay proved to be 0% based on the aligned thermodynamic profiles of the Asp1, Asp2 melting clusters allowing accurate species delimitation of all tested clinical isolates. The identification limit of this HRM assay was also estimated on Aspergillus reference gDNA panels where it proved to be 10-102 genomic equivalents (GE) except the A. fumigatus panel where it was 103 only. Furthermore, misidentification was not detected with human genomic DNA or with Candida, Fusarium, and Scedosporium strains. Our DNA barcoding assay introduced here provides results within a few hours, and it may possess further diagnostic utility when analyzing standard cultures supporting adequate therapeutic decisions.

Prevention of Cyclophosphamide-Induced Immunosuppression in Mice with the Antimicrobial Peptide Sublancin

Sublancin is a glycosylated antimicrobial peptide produced by Bacillus subtilis 168 with combined antibacterial and immunomodulatory activities. The purpose of this study was to evaluate the protective effects of sublancin on immunosuppression in cyclophosphamide-treated mice. In normal mice, the phagocytic activity of mouse peritoneal macrophages was significantly enhanced by oral administration of sublancin (1.0 mg/kg body weight) to BALB/c mice for 7 days (P < 0.01). In addition, the mRNA expression of IL-1β, IL-6, and TNF-α in peritoneal macrophages from sublancin- (1.0 mg/kg body weight) administered mice was significantly increased (P < 0.05). In cyclophosphamide-treated mice, oral sublancin administration accelerated the recovery of peripheral white blood cells, red blood cells, hemoglobins, and platelets and enhanced the macrophage phagocytic activity. Furthermore, sublancin restored the mRNA levels of IL-2, IL-4, and IL-6 in the spleen. Finally, the intestinal absorption of sublancin was poor as detected in the Caco-2 transwell system. Taken together, these findings suggest that sublancin plays a crucial role in the protection against immunosuppression in cyclophosphamide-treated mice and could be a potential candidate for use in immune therapy regimens.

Serum galactomannan for diagnosing invasive aspergillosis in pediatric patients: A meta-analysis

BACKGROUND

The serum galactomannan (GM) assay is used to diagnose invasive aspergillosis (IA). We conducted a systematic review and analysis to estimate the overall accuracy of the serum GM test for diagnosing pediatric IA.

METHOD

A systematic literature review was conducted of all relevant studies published in PubMed and EMbase databases up to March 10, 2017. We selected and assessed articles that reported diagnostic data related to serum GM for diagnosis of pediatric IA. Pooled diagnostic odds ratios (DORs) and summary receiver operating characteristics (SROCs) were constructed with a cutoff value of 0.5. Additionally, pooled sensitivity (SEN), specificity (SPE), and positive and negative likelihood ratios (PLR and NLR, respectively) were estimated for summarizing overall test performance.

RESULTS

Seventeen studies were included in this systematic review. The total number of patients (age range 0-21 years old) was 1768, with 178 that had proven or probable IA. The pooled serum GM assay results, with a cutoff value of 0.5 for proven or probable IA, were DOR: 41.16 (95% confidence interval (CI) 21.48-78.86), SEN: 0.85 (95% CI 0.72-0.93), SPE: 0.88 (95% CI 0.80-0.93), PLR: 6.92 (95% CI 4.40-10.88), and NLR: 0.17 (95% CI 0.09-0.32). The SROC was 0.93.

CONCLUSION

Serum GM can be used to assist in diagnosis of proven or probable pediatric IA. However, serum GM test results should be interpreted in combination with clinical findings in pediatric IA cases, as the test results are not always sensitive or specific enough for pediatric IA.

Acylhydrazones as Antifungal Agents Targeting the Synthesis of Fungal Sphingolipids

The incidence of invasive fungal infections has risen dramatically in recent decades. Current antifungal drugs are either toxic, likely to interact with other drugs, have a narrow spectrum of activity, or induce fungal resistance. Hence, there is a great need for new antifungals, possibly with novel mechanisms of action. Previously our group reported an acylhydrazone called BHBM that targeted the sphingolipid pathway and showed strong antifungal activity against several fungi. In this study, we screened 19 derivatives of BHBM. Three out of 19 derivatives were highly active against Cryptococcus neoformansin vitro and had low toxicity in mammalian cells. In particular, one of them, called D13, had a high selectivity index and showed better activity in an animal model of cryptococcosis, candidiasis, and pulmonary aspergillosis. D13 also displayed suitable pharmacokinetic properties and was able to pass through the blood-brain barrier. These results suggest that acylhydrazones are promising molecules for the research and development of new antifungal agents.

New insights into the clinical characteristics and prognostic factors of pulmonary fungal infections from a retrospective study in Southwestern China

Background

Despite increasing incidence of pulmonary fungal infections (PFIs) worldwide, the clinical characteristics and prognostic factors remain poorly understood. The goal of this study was to investigate the clinical features, laboratory findings, and outcomes of hospitalized patients diagnosed with PFIs.

Methods

We retrospectively enrolled 123 patients at a university hospital in Southwestern China between February 2014 and May 2016, who were diagnosed with PFIs based on clinical presentations and laboratory tests including fungal culture and pathological examination. Medical records were reviewed and analyzed. Prognostic factor associated with mortality was evaluated by multivariate regression analysis.

Results

Of the 123 PFI patients enrolled, the mean age was 67 years with 72% of them being males. In addition to common clinical features reported previously, these patients exhibited distinct characteristics, with the elderly accounting for 79% of all cases, and with prolonged hospitalization being the most prevalent risk factor (74%) and chronic obstructive pulmonary disease (COPD) being the most common underlying disease (45%). Invasive operation was significantly more frequently involved in patients with unfavorable treatment responses than in patients with favorable responses (45.6 vs 7.4%, P=0.000). By multivariate regression analysis, invasive operation (odds ratio [OR]: 5.736, 95% confidence interval [CI]: 2.008–16.389, P=0.001) and hypoalbuminemia (OR: 3.936, 95% CI: 1.325–11.696, P=0.014) were independent prognostic factors of mortality in PFIs.

Conclusion

This study provides new insights into the clinical characteristics and prognostic factors of PFIs and highlights the necessity to be aware of PFIs in patients with COPD and patients receiving invasive operation in order to improve clinical management of these patients.

Relationship of environmental disturbances and the infectious potential of fungi

Fungi are critical organisms for the environment and offer many benefits to modern society through their application in the pharmaceutical, beverage and food industries. In contrast, fungal pathogens are emerging threats to humans, animals, plants and insects with potential to cause devastating mortality, morbidity and economic loss. Outbreaks associated with anthropogenic alterations of the environment, including climate change-related events such as natural disasters, are responsible for human, animal and plant disease. Similarly, fungi and their metabolites also have a negative impact in agriculture, posing a serious threat to our food supplies. Here, we describe the existing knowledge and importance of understanding the relationship of fungi and the environment in the context of human, animal and plant disease. Our goal is to encourage communication between scientists and the general public to create informed awareness about the impact of fungi in their daily lives and their environment.

Retrospective review of immunocompromised children undergoing skin biopsy for suspected invasive infection: Analysis of factors predictive of invasive mold

OBJECTIVES

Cutaneous lesions are often the first marker of invasive mold infection, which can cause substantial morbidity in immunocompromised children. The purpose of this study was to describe the evaluation and outcomes of immunocompromised children who presented with findings requiring skin biopsy because of concern about invasive infection. In children who were biopsied, we sought to determine the factors predictive of invasive mold infection.

METHODS

A retrospective review was conducted at the Children's Hospital of Philadelphia. Patients included in the study were immunocompromised individuals younger than 26 years old who underwent skin biopsy by the inpatient dermatology consultation team between January 1, 2003, and March 15, 2015, because of development of new cutaneous lesions that were suspected of being invasive infection.

RESULTS

One hundred five encounters met the inclusion criteria. Fifty (47.6%) biopsied individuals had an infectious pathogen identified on histopathology or culture. Mold was the most common (36%) pathogen, followed by bacteria (32%) and yeast (26%). The presence of a single lesion (P = .001) and prior occlusion at the site of the lesion (P < .001) were associated with mold on biopsy. The combination of a single lesion, history of occlusion, and tissue necrosis on examination was highly predictive for invasive mold infection (86.3% [95% confidence interval 55.1-97.0%]). Of the 18 individuals with confirmed invasive mold infection, 13 (72%) underwent surgical resection, of whom 12 (92%) survived the 30-day follow-up period.

CONCLUSION

Skin biopsy enabled the detection of a pathogen that informed directed therapeutic interventions in nearly half of participants. Institutions caring for immunocompromised children should ensure adequate staffing of clinical personnel approved to perform skin biopsies.

Primary prophylaxis of invasive fungal infections in patients with haematological malignancies: 2017 update of the recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society for Haematology and Medical Oncology (DGHO)

Immunocompromised patients are at high risk of invasive fungal infections (IFI), in particular those with haematological malignancies undergoing remission-induction chemotherapy for acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS) and recipients of allogeneic haematopoietic stem cell transplants (HSCT). Despite the development of new treatment options in the past decades, IFI remains a concern due to substantial morbidity and mortality in these patient populations. In addition, the increasing use of new immune modulating drugs in cancer therapy has opened an entirely new spectrum of at risk periods. Since the last edition of antifungal prophylaxis recommendations of the German Society for Haematology and Medical Oncology in 2014, seven clinical trials regarding antifungal prophylaxis in patients with haematological malignancies have been published, comprising 1227 patients. This update assesses the impact of this additional evidence and effective revisions. Our key recommendations are the following: prophylaxis should be performed with posaconazole delayed release tablets during remission induction chemotherapy for AML and MDS (AI). Posaconazole iv can be used when the oral route is contraindicated or not feasible. Intravenous liposomal amphotericin B did not significantly decrease IFI rates in acute lymphoblastic leukaemia (ALL) patients during induction chemotherapy, and there is poor evidence to recommend it for prophylaxis in these patients (CI). Despite substantial risk of IFI, we cannot provide a stronger recommendation for these patients. There is poor evidence regarding voriconazole prophylaxis in patients with neutropenia (CII). Therapeutic drug monitoring TDM should be performed within 2 to 5 days of initiating voriconazole prophylaxis and should be repeated in case of suspicious adverse events or of dose changes of interacting drugs (BIItu). General TDM during posaconazole prophylaxis is not recommended (CIItu), but may be helpful in cases of clinical failure such as breakthrough IFI for verification of compliance or absorption.

Analysis of the clinical features of invasive bronchopulmonary aspergillosis

INTRODUCTION

Early diagnosis of invasive bronchopulmonary aspergillosis (IBPA) is difficult, so the mortality rate is high.

OBJECTIVE

To discuss the clinical features of IBPA.

METHODS

We retrospectively analyzed the clinical features, imaging findings, laboratory test, diagnosis and treatment of 115 patients with IBPA diagnosed from October 2004 to June 2013 in Zhongshan Hospital, Fudan University.

RESULTS

The main clinical manifestations were cough in 58 patients (50.4%), expectoration in 37 patients (32.2%), fever in 18 patients (15.7%), shortness of breath in 26 patients (22.6%), hemoptysis in 26 patients (22.6%) and chest pain in 7 patients (6.0%). The main CT findings were nodules in 35 patients (30.4%), consolidation shadows or patchy shadows in 62 patients (53.9%) and cavity in 14 patients (12.2%). Percutaneous pulmonary biopsy was conducted in 25 patients (21.7%), TBLB in 58 patients (50.4%) and thoracoscopic surgery in 32 patients (27.8%). The positive rate of GM test was 73.5% (72/98). Thirty patients who received lobectomy were followed up for 1-3 years. Fifty-five patients who received monotherapy with antifungal agents were followed up for 1-3 years, and 12 patients were healed. The lesions for 23 patients were obviously absorbed, 10 patients had aggravation and two patients died.

CONCLUSIONS

The clinical manifestations of IBPA were unspecific. The main symptoms were cough and expectorate. Patients with different immunologic function had different imaging findings. The halo sign and new moon sign for diagnosis was not as common as reported. Interventional therapy under bronchoscope is very important for patients with ATB.

Pharmacodynamic studies of voriconazole: informing the clinical management of invasive fungal infections

INTRODUCTION

Voriconazole is a broad-spectrum antifungal agent commonly used to treat invasive fungal infections (IFI), including aspergillosis, candidiasis, Scedosporium infection, and Fusarium infection. IFI often occur in immunocompromised patients, leading to increased morbidity and mortality.

AREAS COVERED

The objective of this review is to summarize the pharmacodynamic properties of voriconazole and to provide considerations for potential optimal dosing strategies. Studies have demonstrated superior clinical response when an AUC/MIC >25 or Cmin/MIC >1 is attained in adult patients, correlating to a trough concentration range as narrow as 2-4.5 mg/L; however, these targets are poorly established in the pediatric population. Topics in this discussion include voriconazole use in multiple age groups, predisposing patient factors for IFI, and considerations for clinicians managing IFI. Expert commentary: The relationship between voriconazole dosing and exposure is not well defined due to the large inter- and intra-subject variability. Development of comprehensive decision support tools for individualizing dosing, particularly in children who require higher dosing, will help to increase the probability of achieving therapeutic efficacy and decrease sub-therapeutic dosing and adverse events.

Chronic immunosuppression in the mature patient

In the ever-aging population of the world, the field of geriatrics continues to grow in importance. As human beings age, the skin undergoes a unique array of changes that predispose it to a specific set of dermatoses, infections, and neoplasms. Some of these physiologic alterations are comparable to the changes that happen in immunosuppressed individuals. Given the importance of immunosuppressive medications in treatment of many common skin conditions, we have reviewed the current literature to assist the practicing clinician in using immunosuppressive medications in the geriatric population.

Comparative evaluation of galactomannan test with bronchoalveolar lavage and serum for the diagnosis of invasive aspergillosis in patients with hematological malignancies

INTRODUCTION

Invasive pulmonary aspergillosis (IPA) is a major cause of morbidity and mortality in patients with hematological malignancies. In recent years, testing for values of galactomannan (GM) in serum and bronchoalveolar lavage (BAL) fluid has been investigated as a diagnostic test for IPA for such patients, but global experience and consensus on optical density (OD) cutoffs, especially for BAL galactomannan remains lacking.

METHODS

We performed a prospective case-control study to determine an optimal BAL GM OD cutoff for IPA in at-risk patients. Cases were subjects with hematological diagnoses who met established revised definitions for proven or probable IPA established by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group (EORTC/MSG, 2008), without the use of BAL GM results. Exclusion criteria included the use of piperacillin/tazobactam and use of antifungals that were active against Aspergillus spp. before bronchoscopy. There were two control groups: patients with hematological diagnoses not meeting definitions for proven or probable IPA and patients with nonhematological diagnoses with no evidence of aspergillosis. Following bronchoscopy and BAL, GM testing was performed using the Platelia Aspergillus seroassay in accordance with the manufacturer's instructions.

RESULTS

There were 51 cases and 20 controls. Cases had higher BAL fluid GM OD indices (ODIs) (mean: 1.27 and range: 0.4-3.78) compared with controls (mean: 0.26 and range: 0.09-0.35). Receiver operating characteristic analysis demonstrated an optimum ODI cutoff of 1.0, with high specificity (100%) and sensitivity (87.5%) for diagnosing IPA.

CONCLUSIONS

Our results support BAL GM testing as a reasonably safe test with higher sensitivity compared to serum GM testing in at-risk patients with hematological diseases. A higher OD cutoff is necessary to avoid overdiagnosis of IPA.

Long-term follow up of invasive aspergillosis in allogeneic stem cell transplantation recipients and leukemia patients: Differences in risk factors and outcomes

Antifungal prophylaxis (AP) has dramatically changed the epidemiology of invasive aspergillosis (IA). To better understand the differences in terms of clinical significance of IA between allogeneic stem cell transplantation (allo-SCT) recipients and patients treated for leukemia, we report a single-center study of 735 unselected consecutive patients treated between 2000 and 2004, before the era of systematic AP. Probable or confirmed IA were observed in 29 patients (2008 EORTC/MSG criteria), including 7/235 undergoing allo-SCT (5.2%), 19/380 treated for acute leukemia (5.0%), 1/116 for chronic lymphocytic leukemia (0.9%) and 2/104 for myelodysplastic syndrome (1.9%). In allo-SCT recipients, IA occurred later than in leukemia patients, after the neutropenic period. The median time between the last treatment and the diagnosis of IA was 231 days (range, 68-341) in allo-SCT recipients and 17 days (6-57) in leukemia patients (P<0.001). Importantly, the 7 cases of IA after allo- SCT occurred only in patients treated with corticosteroids for graft-versus-host disease (GVHD). Mortality directly related to IA was 24%. The 100-day, 2-year and 10-year overall survival were 42.9%, 0%, 0% in allo-SCT recipients compared to 68.1%, 18.2%, 13.6% in leukemia patients, respectively (P≥0.05). These poor outcomes were mainly attributable to non-relapse mortality (NRM). In conclusion, our data allows distinguishing 2 types of IA occurring at different time in the treatment course. In both cases, the NRM is very high and treatment remains challenging. Thus, systematic broad-spectrum AP against Aspergillus should be considered in acute leukemia patients during the neutropenic phase and in all patients undergoing allo-SCT who develop GVHD.

Aspergillus fumigatus-induced early inflammatory response in pulmonary microvascular endothelial cells: Role of p38 MAPK and inhibition by silibinin

Human invasive pulmonary aspergillosis (IPA) is a serious infectious disease mainly caused by Aspergillus fumigatus (A. fumigatus). Pulmonary microvascular endothelial cells (PMVECs) are important ones in the human lung tissue. However, it remains unclear about the role of PMVECs in IPA. In the present study, we cocultured PMVECs with A. fumigatus. We observed that A. fumigatus induced dose- and time-dependent increases of interleukin 6 (IL-6), interleukin 1β (IL-1β) and intercellular adhesion molecule 1 (ICAM-1) concentration in the cultures. Significant increases in IL-6, IL-1β, E-selectin, and ICAM-1 mRNA expression were also observed in the cultures treated with A. fumigatus. While preincubation with SB203580 (10μM) did not cause significant changes in IL-6, IL-1β and ICAM-1 concentration in the cocultures, significant IL-6, IL-1β and ICAM-1 concentration decreases were observed in the cocultures preincubated with SB203580 (20μM). Neither SP600125 (10-20μM) nor PD98059 (10-20μM) caused significant changes in IL-6, IL-1β and ICAM-1 concentration in the cocultures. PCR results also showed that SB203580 (20μM) (neither SP600125 (20μM) nor PD98059 (20μM)) preincubation significantly decreased IL-6, IL-1β, E-selectin and ICAM-1 mRNA expression in the cocultures. In addition, significant p38 MAPK phosphorylation increase was observed in the PMVECs cultures treated with A. fumigatus. Furthermore, silibinin pre-treatment and post-treatment were observed to significantly down-regulate mRNA and protein expression of proinflammatory factors and adhesion molecules in the cocultures. Finally, we observed that silibinin significantly inhibited A. fumigatus-induced p38 MAPK activation in PMVECs. Our results indicated that PMVECs might participate in IPA early inflammation which is mediated by p38 MAPK. Silibinin may inhibit A. fumigatus-induced inflammation in PMVECs through p38 MAPK.

Galactofuranose antigens, a target for diagnosis of fungal infections in humans

The use of biomarkers for the detection of fungal infections is of interest to complement histopathological and culture methods. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. D-Galactofuranose (Galf) is the antigenic epitope in glycoconjugates of several pathogenic fungi. Since Galf is not biosynthesized by mammals, it is an attractive candidate for diagnosis of infection. A monoclonal antibody that recognizes Galf is commercialized for detection of aspergillosis. The linkage of Galf in the natural glycans and the chemical structures of the synthesized Galf-containing oligosaccharides are described in this paper. The oligosaccharides could be used for the synthesis of artificial carbohydrate-based antigens, not enough exploited for diagnosis.

D-Galactofuranose (Galf) is the unit in polysaccharides and glycoconjugates of several pathogenic fungi that is recognized by the immune system. Since Galf is not synthesized by mammals, it is an attractive candidate for diagnosis of infection. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. An antibody that recognizes Galf is commercialized for the detection of aspergillosis. Chemically synthesized Galf-containing oligosaccharides, reviewed in this paper, could therefore be used for the synthesis of artificial carbohydrate-based antigens and in diagnosis.

Ecology of aspergillosis: insights into the pathogenic potency of Aspergillus fumigatus and some other Aspergillus species

Fungi of the genus Aspergillus are widespread in the environment. Some Aspergillus species, most commonly Aspergillus fumigatus, may lead to a variety of allergic reactions and life-threatening systemic infections in humans. Invasive aspergillosis occurs primarily in patients with severe immunodeficiency, and has dramatically increased in recent years. There are several factors at play that contribute to aspergillosis, including both fungus and host-related factors such as strain virulence and host pulmonary structure/immune status, respectively. The environmental tenacity of Aspergilllus, its dominance in diverse microbial communities/habitats, and its ability to navigate the ecophysiological and biophysical challenges of host infection are attributable, in large part, to a robust stress-tolerance biology and exceptional capacity to generate cell-available energy. Aspects of its stress metabolism, ecology, interactions with diverse animal hosts, clinical presentations and treatment regimens have been well-studied over the past years. Here, we synthesize these findings in relation to the way in which some Aspergillus species have become successful opportunistic pathogens of human- and other animal hosts. We focus on the biophysical capabilities of Aspergillus pathogens, key aspects of their ecophysiology and the flexibility to undergo a sexual cycle or form cryptic species. Additionally, recent advances in diagnosis of the disease are discussed as well as implications in relation to questions that have yet to be resolved.

IL-12 Influence mTOR to Modulate CD8+ T Cells Differentiation through T-bet and Eomesodermin in Response to Invasive Pulmonary Aspergillosis

Objective: To investigate whether mTOR signaling pathway regulate the proliferation and differentiation of CD8⁺ T cells by transcription factors T-bet and Eomes, and explore the role of IL-12 in this biological procedure. Methods: Aspergillus fumigatus spore suspension nasal inhalation was used to establish the invasive pulmonary aspergillosis (IPA) mouse model. After inoculation, rapamycin (2mg/kg) each day or IL-12 (5ug/kg) every other day was given for 7 days. The blood samples were obtained before the mice sacrificed and lung specimens were taken. Pathological sections were stained with hematoxylin and eosin (HE). The number of CD8⁺effective memory T cells (Tem) and the expression of IFN-γ, mTOR, ribosomal protein S6 kinase (S6K), T-bet and EOMES were measured by flow cytometry. The levels of IL-6, IL-10 and Galactomannan (GM) were determined by ELISA. Results: After IL-12 treatment, the number of CD8⁺ Tem and the expression of IFN-γ increased significantly; while quite the opposite results were observed when the mTOR pathway was blocked by rapamycin. The expression of mTOR and S6K as well as the level of IFN-γ of the IL-12 treatment group were significantly higher than those in IPA and IPA + rapamycin groups. In addition, IL-12 promoted increasing T-bet and down regulating Eomes to make the Tem transformation. The final immune effector was high level of inflammatory cytokines (IL-6) and low level of anti-inflammatory factors (IL-10) and this strengthened immune response to the Aspergillus infection. Conclusions: The biological effects of Tem could significantly affect IPA infection host immune regulation, which depended on the activation of mTOR signaling pathway by IL-12.

Multicenter Study of Method-Dependent Epidemiological Cutoff Values for Detection of Resistance in Candida spp. and Aspergillus spp. to Amphotericin B and Echinocandins for the Etest Agar Diffusion Method

Method-dependent Etest epidemiological cutoff values (ECVs) are not available for susceptibility testing of either Candida or Aspergillus species with amphotericin B or echinocandins. In addition, reference caspofungin MICs for Candida spp. are unreliable. Candida and Aspergillus species wild-type (WT) Etest MIC distributions (microorganisms in a species-drug combination with no detectable phenotypic resistance) were established for 4,341 Candida albicans, 113 C. dubliniensis, 1,683 C. glabrata species complex (SC), 709 C. krusei, 767 C. parapsilosis SC, 796 C. tropicalis, 1,637 Aspergillus fumigatus SC, 238 A. flavus SC, 321 A. niger SC, and 247 A. terreus SC isolates. Etest MICs from 15 laboratories (in Argentina, Europe, Mexico, South Africa, and the United States) were pooled to establish Etest ECVs. Anidulafungin, caspofungin, micafungin, and amphotericin B ECVs (in micrograms per milliliter) encompassing ≥97.5% of the statistically modeled population were 0.016, 0.5, 0.03, and 1 for C. albicans; 0.03, 1, 0.03, and 2 for C. glabrata SC; 0.06, 1, 0.25, and 4 for C. krusei; 8, 4, 2, and 2 for C. parapsilosis SC; and 0.03, 1, 0.12, and 2 for C. tropicalis The amphotericin B ECV was 0.25 μg/ml for C. dubliniensis and 2, 8, 2, and 16 μg/ml for the complexes of A. fumigatus, A. flavus, A. niger, and A. terreus, respectively. While anidulafungin Etest ECVs classified 92% of the Candida fks mutants evaluated as non-WT, the performance was lower for caspofungin (75%) and micafungin (84%) cutoffs. Finally, although anidulafungin (as an echinocandin surrogate susceptibility marker) and amphotericin B ECVs should identify Candida and Aspergillus isolates with reduced susceptibility to these agents using the Etest, these ECVs will not categorize a fungal isolate as susceptible or resistant, as breakpoints do.

Special Issue: Novel Antifungal Drug Discovery

This Special Issue is designed to highlight the latest research and development on new antifungal compounds with mechanisms of action different from the ones of polyenes, azoles, and echinocandins. The papers presented here highlight new pathways and targets that could be exploited for the future development of new antifungal agents to be used alone or in combination with existing antifungals. A computational model for better predicting antifungal drug resistance is also presented.

Aspergillus fumigatus CalA binds to integrin α5β1 and mediates host cell invasion

Aspergillus fumigatus is an opportunistic fungal pathogen that invades pulmonary epithelial cells and vascular endothelial cells by inducing its own endocytosis, but the mechanism by which this process occurs is poorly understood. Here, we show that the thaumatin-like protein CalA is expressed on the surface of the A. fumigatus cell wall, where it mediates invasion of epithelial and endothelial cells. CalA induces endocytosis in part by interacting with integrin α₅β₁ on host cells. In corticosteroid-treated mice, a ΔcalA deletion mutant has significantly attenuated virulence relative to the wild-type strain, as manifested by prolonged survival, reduced pulmonary fungal burden and decreased pulmonary invasion. Pretreatment with an anti-CalA antibody improves survival of mice with invasive pulmonary aspergillosis, demonstrating the potential of CalA as an immunotherapeutic target. Thus, A. fumigatus CalA is an invasin that interacts with integrin α₅β₁ on host cells, induces endocytosis and enhances virulence.

Reorganization of plasma membrane lipid domains during conidial germination

Neurospora crassa, a filamentous fungus, in the unicellular conidial stage has ideal features to study sphingolipid (SL)-enriched domains, which are implicated in fundamental cellular processes ranging from antifungal resistance to apoptosis. Several changes in lipid metabolism and in the membrane composition of N. crassa occur during spore germination. However, the biophysical impact of those changes is unknown. Thus, a biophysical study of N. crassa plasma membrane, particularly SL-enriched domains, and their dynamics along conidial germination is prompted. Two N. crassa strains, wild-type (WT) and slime, which is devoid of cell wall, were studied. Conidial growth of N. crassa WT from a dormancy state to an exponential phase was accompanied by membrane reorganization, namely an increase of membrane fluidity, occurring faster in a supplemented medium than in Vogel's minimal medium. Gel-like domains, likely enriched in SLs, were found in both N. crassa strains, but were particularly compact, rigid and abundant in the case of slime cells, even more than in budding yeast Saccharomyces cerevisiae. In N. crassa, our results suggest that the melting of SL-enriched domains occurs near growth temperature (30°C) for WT, but at higher temperatures for slime. Regarding biophysical properties strongly affected by ergosterol, the plasma membrane of slime conidia lays in between those of N. crassa WT and S. cerevisiae cells. The differences in biophysical properties found in this work, and the relationships established between membrane lipid composition and dynamics, give new insights about the plasma membrane organization and structure of N. crassa strains during conidial growth.

Immunologic and Pharmacologic Aspects in an Elderly Recipient of Liver Transplant With Pulmonary Aspergillosis and Multiple Comorbidities

The net state of immunosuppression, the occurrence of infections, drug-drug interactions, and toxicity can compromise the outcome of liver transplant recipients with multiple comorbidities. We present a 67-year-old man who developed early posttransplant severe chronic obstructive pulmonary disease exacerbation, pulmonary aspergillosis, and cytomegalovirus reactivation. Drug-drug interactions between azoles and cyclosporine, along with renal and liver toxicity, required adjustments in dosage. Interferon-gamma production from antigen-stimulated T cells was recorded. Early diagnosis and treatment, along with therapeutic drug monitoring and recovery of T-cell immunity, were key factors for a positive outcome.

Economic evaluation of azoles as primary prophylaxis for the prevention of invasive fungal infections in Spanish patients undergoing allogeneic haematopoietic stem cell transplant

Patients undergoing allogeneic haematopoietic stem cell transplantation (alloHSCT) are at risk of developing invasive fungal infections (IFIs). Even with introduction of oral triazole antifungal agents (fluconazole, itraconazole, posaconazole and voriconazole) IFI-associated morbidity and mortality rates and economic burden remain high. Despite their proven efficacy, it is currently unknown which is the most cost-effective antifungal prophylaxis (AFP) agent. To determine the costs and outcomes associated with AFP, a decision-analytic model was used to simulate treatment in a hypothetical cohort of 1000 patients undergoing alloHSCT from the perspective of the Spanish National Health System. Generic itraconazole was the least costly AFP (€162) relative to fluconazole (€500), posaconazole oral suspension (€8628) or voriconazole (€6850). Compared with posaconazole, voriconazole was associated with the lowest number of breakthrough IFIs (36 vs 60); thus, the model predicted fewer deaths from breakthrough IFI for voriconazole (24) than posaconazole (33), and the lowest predicted costs associated with other licensed antifungal treatment and IFI treatment in a cohort of 1000. Voriconazole resulted in cost savings of €4707 per patient compared with posaconazole. Itraconazole demonstrated a high probability of being cost-effective. As primary AFP in alloHSCT patients 180 days posttransplant, voriconazole was more likely to be cost-effective than posaconazole regarding cost per additional IFI and additional death avoided.

Triazole Resistance in Aspergillus spp.: A Worldwide Problem?

Since the first description of an azole-resistant A. fumigatus strain in 1997, there has been an increasing number of papers describing the emergence of azole resistance. Firstly reported in the USA and soon after in Europe, it has now been described worldwide, challenging the management of human aspergillosis. The main mechanism of resistance is the modification of the azole target enzyme: 14-α sterol demethylase, encoded by the cyp51A gene; although recently, other resistance mechanisms have also been implicated. In addition, a shift in the epidemiology has been noted with other Aspergillus species (mostly azole resistant) increasingly being reported as causative agents of human disease. This paper reviews the current situation of Aspergillus azole resistance and its implications in the clinical setting.

High Intracellular Concentrations of Posaconazole Do Not Impact on Functional Capacities of Human Polymorphonuclear Neutrophils and Monocyte-Derived Macrophages In Vitro

Posaconazole is a commonly used antifungal for the prophylaxis and treatment of invasive fungal infections. We previously demonstrated that the intracellular concentration of posaconazole in peripheral blood mononuclear cells (PBMCs) and polymorphonuclear neutrophils (PMNs) was greatly increased compared to the plasma concentration. As these professional phagocytes are crucial to combat fungal infections, we set out to investigate if and how, beneficial or deleterious, this high loading of intracellular posaconazole impacts the functional capacities of these cells. Here, we show that high intracellular concentrations of posaconazole do not significantly impact PMN and monocyte-derived macrophage function in vitro In particular, killing capacity and cytoskeletal features of PMN, such as migration, are not affected, indicating that these cells serve as vehicles for posaconazole to the site of infection. Moreover, since posaconazole as such slowed the germination of Aspergillus fumigatus conidia, infected neutrophils released less reactive oxygen species (ROS). Based on these findings, we propose that the delivery of posaconazole by neutrophils to the site of Aspergillus species infection warrants control of the pathogen and preservation of tissue integrity at the same time.

Use of intravoxel incoherent motion diffusion-weighted MR imaging for assessment of treatment response to invasive fungal infection in the lung

OBJECTIVES

The purpose of this study was to determine whether intravoxel incoherent motion (IVIM) -derived parameters and apparent diffusion coefficient (ADC) could act as imaging biomarkers for predicting antifungal treatment response.

METHODS

Forty-six consecutive patients (mean age, 33.9 ± 13.0 y) with newly diagnosed invasive fungal infection (IFI) in the lung according to EORTC/MSG criteria were prospectively enrolled. All patients underwent diffusion-weighted magnetic resonance (MR) imaging at 3.0 T using 11 b values (0-1000 sec/mm²). ADC, pseudodiffusion coffiecient D*, perfusion fraction f, and the diffusion coefficient D were compared between patients with favourable (n=32) and unfavourable response (n=14).

RESULTS

f values were significantly lower in the unfavourable response group (12.6%±4.4%) than in the favourable response group (30.2%±8.6%) (Z=4.989, P<0.001). However, the ADC, D, and D* were not significantly different between the two groups (P>0.05). Receiver operating characteristic curve analyses showed f to be a significant predictor for differentiation, with a sensitivity of 93.8% and a specificity of 92.9%.

CONCLUSIONS

IVIM-MRI is potentially useful in the prediction of antifungal treatment response to patients with IFI in the lung. Our results indicate that a low perfusion fraction f may be a noninvasive imaging biomarker for unfavourable response.

KEY POINTS

• Recognition of IFI indicating clinical outcome is important for treatment decision-making. • IVIM can reflect diffusion and perfusion information of IFI lesions separately. • Perfusion characteristics of IFI lesions could help differentiate treatment response. • An initial low f may predict unfavourable response in IFI.

Disseminated aspergillosis causing intestinal failure following colectomy for perforated colitis

Disseminated aspergillosis is a rare, invasive, opportunistic, fungal infection associated with a high mortality. We report a non-fatal case diagnosed following extensive enterectomy for intestinal infarction in a patient recovering from emergency abdominal colectomy for perforated ulcerative colitis. This resulted in intestinal failure necessitating life-long parenteral nutrition and prolonged antifungal therapy.

Evaluation of pulmonary nodules and infection on chest CT with radiation dose equivalent to chest radiography: Prospective intra-individual comparison study to standard dose CT

PURPOSE

To compare prospectively, in patients undergoing chest computed tomography (CT) for pulmonary-nodules or infection, image-quality and accuracy of standard dose (SD) and reduced dose (RD) CT with tin-filtration.

MATERIAL AND METHODS

This IRB-approved study included 100 consecutive patients (36 female;median age 56 years) referred for follow-up of pulmonary-nodules (n=43) or suspicion of infection (n=57) undergoing single-energy CT with SD and RD using tin-filtration at 100 kVp (CTDIvol 2.47 mGy and 0.07 mGy, respectively). Images were reconstructed with advanced modeled iterative reconstruction (ADMIRE) at strength 3 and 5. Image-noise was measured. Two independent readers evaluated nodules and pulmonary-infection. SD CT served as reference standard.

RESULTS

No significant difference was found in noise between RD with ADMIRE5 and SD with ADMIRE3 (118HU ± 14 vs. 120HU ± 17; p=0.08). Sensitivity for detection of atelectasis and interstitial lung changes was higher in images reconstructed with ADMIRE5 (93% and 88%; respectively) than in those reconstructed with ADIMRE3 (77% and 78%; respectively). Sensitivity for detection of consolidations was 90% for ADMIRE3 and 89% for ADMIRE5. Sensitivity for nodule detection was 71% for ADMIRE3 and 81% for ADMIRE5. Specificity for detection of atelectasis and interstitial lung changes was 99% and 96% with ADMIRE5 and 99% and 96% with ADMIRE3. Specificity for detection of consolidations was 99% for ADMIRE3 and 5. Specificity for detection of nodules was 87% for both ADMIRE3 and 5.

CONCLUSION

Chest CT with a radiation dose equivalent to conventional radiography is feasible and allows for detection of pulmonary infection with high sensitivity, whereas the accuracy for detecting nodules is only moderate.

The effect of clinical characteristics on the performance of galactomannan and PCR for the diagnosis of invasive aspergillosis in febrile neutropenic patients

Rapid diagnosis and early treatment of invasive aspergillosis is crucial for the management of the patients with haematological malignancy. We evaluated 358 sera from 78 febrile neutropenic episodes in patient with invasive aspergillosis (IA) (one proven, 17 probable, and 60 possible) and 83 episodes in patients with no IA according to the EORTC/MSG criteria. Patient's specimens were tested by Mycassay Aspergillus PCR (first commercial real-time PCR test) and in house real-time PCR to investigate the presence of Aspergillus DNA, and by ELISA for detect the galactomannan (GM) antigen. We systematically investigated the medical background that can be effective on the test results. The hospitalisation period was longer in proven/probable episodes when compared with no IA (P = 0.001) and possible episodes. With regard to duration of neutropenia, the differences between both proven/probable with no IA (P = 0.023) and possible with no IA (P = 0.002) were highly significant. Similarly, the rates of T cell suppressant therapy in group proven/probable and possible episodes were significantly higher than in no IA (P = 0.005). There are significant differences in the performance of GM and PCR-based tests among studies, and standardisation is required. Therefore, it can be useful to determine the effective factors on these tests. The use of larger volume of sera improved the performance of real-time PCR for detection of Aspergillus DNA in high-risk adult patients in the present study. Some host factors such as duration of neutropenia and administration of T cell suppressants related to the development of IA.

Redundant synthesis of a conidial polyketide by two distinct secondary metabolite clusters in Aspergillus fumigatus

Filamentous fungi are renowned for the production of bioactive secondary metabolites. Typically, one distinct metabolite is generated from a specific secondary metabolite cluster. Here, we characterize the newly described trypacidin (tpc) cluster in the opportunistic human pathogen Aspergillus fumigatus. We find that this cluster as well as the previously characterized endocrocin (enc) cluster both contribute to the production of the spore metabolite endocrocin. Whereas trypacidin is eliminated when only tpc cluster genes are deleted, endocrocin production is only eliminated when both the tpc and enc non-reducing polyketide synthase-encoding genes, tpcC and encA, respectively, are deleted. EncC, an anthrone oxidase, converts the product released from EncA to endocrocin as a final product. In contrast, endocrocin synthesis by the tpc cluster likely results from incomplete catalysis by TpcK (a putative decarboxylase), as its deletion results in a nearly 10-fold increase in endocrocin production. We suggest endocrocin is likely a shunt product in all related non-reducing polyketide synthase clusters containing homologues of TpcK and TpcL (a putative anthrone oxidase), e.g. geodin and monodictyphenone. This finding represents an unusual example of two physically discrete secondary metabolite clusters generating the same natural product in one fungal species by distinct routes.

Aspergillus colonization in patients with chronic obstructive pulmonary disease

Background and Purpose:

Chronic obstructive pulmonary disease (COPD) has been recognized as a risk factor for invasive aspergillosis. Airway colonization by Aspergillus species is a common feature of chronic pulmonary diseases. Nowadays, the incidence of COPD has increased in critically ill patients. The aim of the present study was to isolate and identify Aspergillus colonies in the respiratory tract of COPD patients.

Materials and Methods:

This study was performed on 50 COPD patients, who were aged above 18 years, and were in intensive care units of three hospitals in Sari, Iran, for at least six days. All the samples obtained from sputum, bronchoalveolar lavage, and tracheal aspirates were cultured for fungi each week. According to the conventional techniques, Aspergillus isolates were initially based on growth and standard morphological characteristics. To confirm the identification of grown Aspergillus, the partial beta-tubulin gene was sequenced using specific primers.

Results:

A total of 50 patients, who met our inclusion criteria, were enrolled in the study during 2012-14. The results showed that 27 (54%) and 23 (46%) of the participants were male and female, respectively. The majority of the patients developed dyspnea followed by hemoptysis, chest pain, and high fever. Corticosteroids and broad-spectrum antibacterial agents were administered to 75% and 80% of the patients, respectively. Based on the conventional and molecular approaches, A. fumigatus (seven cases; 43.7%), A. flavus (five cases; 31.2%), A. niger (one case; 6.2%), A. terreus (one case; 6.2%), A. orezea (one case; 6.2%), and A. tubingensis (one case; 6.2%) were recovered.

Conclusion:

Recovery of Aspergillus species from the respiratory tract of COPD patients with pneumonia indicates two possibilities: either colonization or invasive aspergillosis.