Aspergillus Felis Research Articles

Two New Antifungal Indole Alkaloids from an Endophytic Fungi Aspergillus felis Obtained from Cigar Tobacco

Two New Antifungal Indole Alkaloids from an Endophytic Fungi Aspergillus felis Obtained from Cigar Tobacco

Three new isoquinoline alkaloids from the cigar tobacco-derived endophytic fungus Aspergillus felis

The isoquinoline alkaloids have attracted widespread attention from chemists and biologists due to their complex structures and prominent bioactivities. With the aims of screening for antiviral compounds produced by fungi, in this study, three new (1-3), together with four known (4–7) isoquinolines were isolated from the cigar tobacco-derived endophytic fungus Aspergillus felis. Their structures were determined by means of HRESIMS and NMR spectroscopic studies. Interestingly, an anti-TMV test revealed that compounds 2 and 4 showed high activity with inhibition rates of 43.2% and 38.4%, respectively. These rates are higher than those of the positive control ningnanmycin (33.2%). The isolation of the above isoquinolines may provide materials for the study of more potent anti-TMV inhibitors and contribute to an improved utilization of cigar tobacco-derived endophytic fungi.

Comments on Case Report: A fatal case of Aspergillus felis infection in an immunocompetent host.

Comments on Case Report: A fatal case of Aspergillus felis infection in an immunocompetent host.

Diversity and Distribution of Aspergillus fumigatus and Its Related Species in Izu and Ogasawara Islands, Japan.

The taxon Aspergillus section Fumigati comprises several causative agents of aspergillosis. Here, the distribution of Aspergillus sect. Fumigati in outdoor environments of Izu and Ogasawara Islands was investigated. Different strains were isolated from soil samples collected from 68 sites on 9 islands (Izu-oshima, Toshima, Shikinejima, Kozushima, Miyakejima, Hachijojima, Mukojima, Chichijima, and Hahajima), including different landscapes, and identified using morphological characteristics and calmodulin (CaM) sequences. Seven Aspergillus sect. Fumigati species were identified. The occurrence frequency of Aspergillus fumigatus was higher in forest sites on the islands, except for Ogasawara Islands, whereas that of species other than A. fumigatus was higher in bare land and grassland sites on all islands. The occurrence frequency of A. fumigatus was more than 50% on islands between Izu-oshima and Toshima, decreased on islands between Shikinejima and Hachijojima, and was zero on Ogasawara Islands. Considering other Aspergillus species, Aspergillus felis showed high occurrence frequency on islands between Izu-oshima and Shikinejima, Aspergillus pseudoviridinutans on islands between Kozushima and Hachijojima, and Aspergillus udagawae on Ogasawara Islands. At two study sites (grassland and forest sites), the soil was sampled throughout the year to evaluate whether the occurrence frequency of each fungal species was affected by sampling season. At the grassland site, A. pseudoviridinutans was isolated at more than 90% frequency, regardless of the sampling season. A. fumigatus occurrence frequency at the forest site ranged from 0% to 60% and greatly varied among sampling seasons. Thus, differences in island location and landscape affected the distribution of Aspergillus sect. Fumigati.

First reported human death due to invasive Aspergillus felis infection in an immunocompetent host

First reported human death due to invasive Aspergillus felis infection in an immunocompetent host

Molecular Characterization of Fungi Associated with Dump Site Soil

Aims: A study was conducted to identify fungal species isolated from dumpsite soil in University of Port Harcourt using molecular techniques.
 Methodology: Molecular methods for determining the species of a fungus based on the amplification and sequencing of the internal subscribed spacer (ITS) region of the fungal rRNA operon using molecular markers was applied. Soil sample was collected from a dumpsite in the University of Port Harcourt, Rivers State, Nigeria. Isolation of fungi associated with the dumpsite soil was carried out using spread plate method. Fungal genomic DNA was extracted using Quick-DNA Fungal/Bacterial Miniprep kit. The ITS1-2 gene of the isolates was amplified by Polymerase Chain Reaction (PCR) using the primer pair; ITS4 and ITS5.
 Results: The sequences of the amplified ITS region were blasted against known sequences on the National Centre for Biotechnology Information (NCBI) database. Nucleotide sequence analysis revealed the species identity of the fungal isolates to be: Aspergillus fumigatus, Trichoderma harzianum, Aspergillus felis, Aspergillus templicola, Aspergillus flavipes, Aspergillus fumigatus and Cunninghamella binariae. Phylogenetic analysis was carried out to ascertain the relationship between the isolates and other closely-related isolates on GenBank. Isolates 2 (Trichoderma harzianum) and 7 (Cunninghamella binariae), 3 (Aspergillus felis) and 6 (Aspergillus fumigatus), and 4 (Aspergillus templicola) and 5 (Aspergillus flavipes) were found to be more closely related to each other.
 Conclusion: The molecular techniques employed successfully identified the organisms to the species level as these techniques are based on the genetic constitution of organisms. The result obtained from this study will complement the information on the fungal organisms associated with dumpsite soil.

Disseminated invasive aspergillosis caused by Aspergillus felis in a cat

A 2‐year‐old male desexed Ragdoll cat with a 1‐year history of sneezing and nasal discharge presented with a large subcutaneous cervical mass, identified as the right medial retropharyngeal lymph node on computed tomography (CT). A right orbital mass, destructive sino‐nasal cavity disease and multiple pulmonary nodules were also identified. Aspergillus felis was cultured from the lymph node. After treatment with posaconazole and liposomal amphotericin B the lymph node enlargement and orbital mass resolved but left frontal sinus involvement and pulmonary lesions persisted despite additional caspofungin therapy. The cat was euthanized 14 months after diagnosis with dysphagia and chronic progressive exophthalmos. A meningeal granuloma with intravascular fungal hyphae was identified at post‐mortem and A felis was cultured from the left frontal sinus and a right retrobulbar fungal granuloma. This case demonstrates that disseminated disease is a possible sequel to invasive fungal rhinosinusitis caused by A felis in cats.

Ubiquitous Distribution of Azole-Resistant Aspergillus fumigatus- Related Species in Outdoor Environments in Japan.

Aspergillus fumigatus-related species are responsible for causing aspergillosis, which is a fatal infectious disease. Recently, there has been a series of reports of A. fumigatus-related species that are resistant to azole drugs used in clinical practice for the treatment of fungal infections. Some of these species have been isolated from outdoor environments. Testing the drug susceptibility of the strains from outdoor environments, therefore, is important. In this study, we isolated and cultured 72 strains of A. fumigatus-related species from the outdoor environment in Japan. The isolates identified via morphological observation and molecular phylogenetic analysis were Aspergillus felis, Aspergillus lentulus, Aspergillus pseudoviridinutans, Aspergillus udagawae, and Aspergillus wyomingensis. The results of the drug susceptibility testing revealed that A. felis (6 of 14 strains) and A. pseudoviridinutans (13 of 17 strains) were resistant to itraconazole (ITCZ), with 4 mg/L or higher minimum inhibitory concentrations (MICs). The voriconazole (VRCZ)-resistant strains with 4 mg/L or higher MICs were A. felis (14 of 14), A. lentulus (4 of 4), A. pseudoviridinutans (15 of 17), A. udagawae (23 of 34), A. wyomingensis (1 of 3), and A. pseudoviridinutans (1 of 3). Among them, A. felis (1 of 14) and A. pseudoviridinutans (7 of 17) demonstrated 8 mg/L or higher MICs for ITCZ and VRCZ. These results indicate that A. fumigatus-related species resistant to ITCZ and VRCZ are widely distributed in outdoor environments in Japan.

Effects of cytochalasin E on Paracoccidioides brasiliensis.

To determine the effects of cytochalasin E, isolated from the extremophile fungus Aspergillus felis, on the cells of Paracoccidioides brasiliensis Pb18. Cytochalasin E showed a minimal inhibitory concentration of 3·6μmoll-1 and minimum fungicidal concentration of 7·2μmoll-1 on P. brasiliensis by invitro microdilution and IC50 >964·0μmoll-1 on murine macrophages. Its selectivity index (>263) indicated that this compound has selectivity for fungal cells. Morphological alterations were determined by optical and fluorescence microscopy, as well as scanning and transmission electron microscopy. Cytochalasin E affected P. brasiliensis bud-forming pseudohyphae, cell morphology, cell walls and cell membranes; caused the release of cellular material; and resulted in the production of reactive oxygen species. In murine macrophages, it affected cytoskeletal actin and inhibited phagocytosis. Cytochalasin E may be useful as an antifungal prototype against P. brasiliensis and in studies on phagocytosis. Paracoccidioides spp. are the etiological agents of paracoccidioidomycosis (PCM). Treatment is prolonged to control the clinical manifestations and prevent relapse. The study on the effects of cytochalasin E in P. brasiliensis is important because it can be used as a prototype for new antifungal drugs and consequently, broadens the treatment options for PCM.

Biodiversity of species of Aspergillus section Fumigati in semi-desert soils in Argentina

The distribution of Aspergillus species in soil has been widely studied all over the world. The aim of this study was the phenotypic and genotypic characterization of species Aspergillus belonging to section Fumigati present in soils from two Argentinian semi-desert areas having different geological conditions. Altogether, 23 isolates belonging to Aspergillus section Fumigati were recovered and identified using a polyphasic approach including phenotypic and molecular identifications. Aspergillus fumigatus sensu stricto and Aspergillus fumigatiaffinis had the highest frequency, of occurrence while isolates closely related to Aspergillus udagawae and Aspergillus felis were rarely observed. A. fumigatiaffinis and isolates closer to A. udagawae were isolated for the first time from Argentinian soils and this is the first report on the occurrence of species belonging to the A. felis clade in South America. Recent scientific interests in biodiversity, as well as the increasing importance of aspergilli as causative agents of human and animal diseases increase the need to understand the diversity and occurrence of these fungi in nature.

Small Animal Aspergillosis and Cryptococcosis in Japan

Canine and feline upper respiratory tract (URT) infection due to Aspergillus spp. is considered an emerging disease, with the number of reported cases continuing to rise in Japan. Aspergillus fumigatus has been the most frequently reported etiologic agent of sino-orbital aspergillosis in dogs and cats; the other Aspergillus species, Aspergillus felis, Aspergillus fischeri, Aspergillus udagawae, Aspergillus viridinutans, and A. fumigatus, have also been implicated in feline cases. The minimum inhibitory concentrations (MICs) of antifungal drugs are elevated for these cryptic species compared with A. fumigatus. Some reports showed that the feline infections due to cryptic species did not respond to treatment with antifungal drugs. These results suggest that species identification and antifungal susceptibility testing of infecting agents are important to ensure effective treatment of feline URT aspergillosis. Feline cryptococcosis in Japan is typically attributed to Cryptococcus neoformans var. grubii. We isolated a fluconazole-resistant strain of C. grubii from a feline cryptococcosis. The predicted amino acid sequence of the lanosterol 14-α demethylase gene (ERG11) protein in the isolate was identical to that of the C. grubii reference strain. RT-PCR analysis of ERG11 and ATP binding cassette (ABC) transporter-encoding gene (AFR1) indicated that the isolate had increased transcription factor function for ERG11 and AFR1 compared with fluconazole-susceptible strains. This observation, in combination with the lack of resistance to other azoles (that is, lack of cross resistance), suggests that resistance in our isolate was the result of overexpression of the endogenous ERG11 and ABC transporter. Further ecological and epidemiological studies on small animal mycoses in Japan are needed to monitor the emergence of antifungal drug resistant strains.

Alkaloidal metabolites from Aspergillus felis and their activities against Paracoccidioides brasiliensis

In this study, the fungus Aspergillus felis (strain UFMGCB 8030) was isolated from rocks in the Atacama Desert, Chile. Its CH2Cl2 extract exhibited antifungal activity (MIC of 1.9μg/mL) against Paracoccidioides brasiliensis (Pb18), which is the etiological agent for paracoccidioidomycosis. The crude extract was purified, and a new cytochalasin derivative, cytochalasin Z15E (1), and one ardeemin derivative, 5-N-acetyl-8-β-isopropyl-ardeemin (4), in addition to five known secondary metabolites, rosellichalasin (2), cytochalasin E (3), gancidin (5), pseurotin A1 (6), and 2,4-dihydroxyacetophenone (7), were isolated. The structures of these compounds were confirmed by 1D and 2D NMR spectroscopy and HR-ESI⿿MS. Cytochalasin E was the most active compound with MIC an value of 3.6μM, while the other isolated compounds exhibited weak antifungal activities (MIC values >100.0μM).

Antifungal activity of extracts from Atacama Desert fungi against Paracoccidioides brasiliensis and identification of Aspergillus felis as a promising source of natural bioactive compounds.

Fungi of the genus Paracoccidioides are responsible for paracoccidioidomycosis. The occurrence of drug toxicity and relapse in this disease justify the development of new antifungal agents. Compounds extracted from fungal extract have showing antifungal activity. Extracts of 78 fungi isolated from rocks of the Atacama Desert were tested in a microdilution assay against Paracoccidioides brasiliensis Pb18. Approximately 18% (5) of the extracts showed minimum inhibitory concentration (MIC) values≤ 125.0 µg/mL. Among these, extract from the fungus UFMGCB 8030 demonstrated the best results, with an MIC of 15.6 µg/mL. This isolate was identified as Aspergillus felis (by macro and micromorphologies, and internal transcribed spacer, β-tubulin, and ribosomal polymerase II gene analyses) and was grown in five different culture media and extracted with various solvents to optimise its antifungal activity. Potato dextrose agar culture and dichloromethane extraction resulted in an MIC of 1.9 µg/mL against P. brasiliensis and did not show cytotoxicity at the concentrations tested in normal mammalian cell (Vero). This extract was subjected to bioassay-guided fractionation using analytical C18RP-high-performance liquid chromatography (HPLC) and an antifungal assay using P. brasiliensis. Analysis of the active fractions by HPLC-high resolution mass spectrometry allowed us to identify the antifungal agents present in the A. felis extracts cytochalasins. These results reveal the potential of A. felis as a producer of bioactive compounds with antifungal activity.

Detection of Aspergillus-specific antibodies by agar gel double immunodiffusion and IgG ELISA in feline upper respiratory tract aspergillosis

Feline upper respiratory tract aspergillosis (URTA) is an emerging infectious disease. The aims of this study were: (1) to assess the diagnostic value of detection of Aspergillus-specific antibodies using an agar gel double immunodiffusion (AGID) assay and an indirect immunoglobulin G (IgG) ELISA; and (2) to determine if an aspergillin derived from mycelia of Aspergillus fumigatus, Aspergillus niger and Aspergillus flavus can be used to detect serum antibodies against cryptic Aspergillus spp. in Aspergillus section Fumigati. Sera from cats with URTA (group 1: n = 21) and two control groups (group 2: cats with other upper respiratory tract diseases, n = 25; group 3: healthy cats and cats with non-respiratory, non-fungal illness, n = 84) were tested. Isolates from cats with URTA comprised A. fumigatus (n = 5), A. flavus (n = 1) and four cryptic species: Aspergillus felis (n = 12), Aspergillus thermomutatus (Neosartorya pseudofischeri, n = 1), Aspergillus lentulus (n = 1) and Aspergillus udagawae (n = 1).Brachycephalic purebred cats were significantly more likely to develop URTA than other breeds (P = 0.013). The sensitivity (Se) of the AGID was 43% and the specificity (Sp) was 100%. At a cut-off value of 6 ELISA units/mL, the Se of the IgG ELISA was 95.2% and the Sp was 92% and 92.9% for groups 2 and 3 cats, respectively. Aspergillus-specific antibodies against all four cryptic species were detected in one or both assays. Assay Se was not associated with species identity. Detection of Aspergillus-specific antibodies by IgG ELISA has high Se and Sp for diagnosis of feline URTA.

Multi-resistant aspergillosis due to cryptic species.

Reports of cryptic species causing aspergillosis in humans are increasing in the literature. Cryptic species are defined as those which are morphologically indistinguishable, although their identifications can be confirmed using molecular or other techniques which continue to become more widely available in the clinical setting. Antifungal resistance has often been noted in these cases, and indeed there does appear to be a higher prevalence of reduced susceptibility in cryptic species. Many of these observations are published as individual case reports or as a small component of larger data sets, making it challenging to review and compare the data fully. This review article seeks to describe the susceptibility trends and key learning outcomes of specific cases of infections caused by cryptic species, including Aspergillus alliaceus, Aspergillus calidoustus, Aspergillus felis, Aspergillus lentulus, Aspergillus tubingensis, Aspergillus viridinutans and Neosartorya pseudofischeri. These reports highlight the clinical need for full accurate identification and susceptibility testing to guide patient care.

Computed tomographic features of feline sino-nasal and sino-orbital aspergillosis

Feline upper respiratory tract aspergillosis (URTA) occurs as two distinct anatomical forms, namely, sino-nasal aspergillosis (SNA) and sino-orbital aspergillosis (SOA). An emerging pathogen, Aspergillus felis, is frequently involved. The pathogenesis of URTA, in particular the relationship between the infecting isolate and outcome, is poorly understood. In this study, computed tomography was used to investigate the route of fungal infection and extension in 16 cases (SNA n = 7, SOA n = 9) where the infecting isolate had been identified by molecular testing.All cases had nasal cavity involvement except for one cat with SNA that had unilateral frontal sinus changes. There was a strong association between the infecting species and anatomic form (P = 0.005). A. fumigatus infections remained within the sino-nasal cavity, while cryptic species infections were associated with orbital and paranasal soft-tissue involvement and with orbital lysis. Cryptic species were further associated with a mass in the nasal cavity, paranasal sinuses or nasopharynx. Orbital masses showed heterogeneous contrast enhancement, with central coalescing hypoattenuating foci and peripheral rim enhancement. Severe, cavitated turbinate lysis, typical of canine SNA, was present only in cats with SNA. These findings support the hypothesis that the nasal cavity is the portal of entry for fungal spores in feline URTA and that the route of extension to involve the orbit is via direct naso-orbital communication from bone lysis. Additionally, a pathogenic role for A. wyomingensis and a sinolith in a cat with A. udagawae infection are reported for the first time.