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G. S. De Hoog - One of the best experts on this subject based on the ideXlab platform.

  • Combination of Amphotericin B and Terbinafine against Melanized Fungi Associated with Chromoblastomycosis
    Antimicrobial Agents and Chemotherapy, 2018
    Co-Authors: Shuwen Deng, G. S. De Hoog, L. Yang, Roxana G. Vitale, Haleh Rafati, M. Seyedmousavi, Ali Tolooe, Wanqing Liao
    Abstract:

    Our in vitro studies showed that a combination of amphotericin B and terbinafine had synergistic effects against the majority of melanized fungi associated with chromoblastomycosis (CBM) and similar infections, including those with Cladophialophora carrionii , Cladophialophora arxii , Exophiala dermatitidis , Exophiala spinifera , Fonsecaea monophora , Fonsecaea nubica , Fonsecaea pedrosoi , and Phialophora verrucosa. This drug combination could provide an option for the treatment of severe or unresponsive cases of CBM, particularly in cases due to species of Fonsecaea and Cladophialophora .

  • detection and identification of opportunistic Exophiala species using the rolling circle amplification of ribosomal internal transcribed spacers
    Journal of Microbiological Methods, 2013
    Co-Authors: Mohammad Javad Najafzadeh, Somayeh Dolatabadi, Saradeghi M Keisari, Ali Naseri, Peiying Feng, G. S. De Hoog
    Abstract:

    Deep infections by melanized fungi deserve special attention because of a potentially fatal, cerebral or disseminated course of disease in otherwise healthy patients. Timely diagnostics are a major problem with these infections. Rolling circle amplification (RCA) is a sensitive, specific and reproducible isothermal DNA amplification technique for rapid molecular identification of microorganisms. RCA-based diagnostics are characterized by good reproducibility, with few amplification errors compared to PCR. The method is applied here to species of Exophiala known to cause systemic infections in humans. The ITS rDNA region of five Exophiala species (E. dermatitidis, E. oligosperma, E. spinifera, E. xenobiotica, and E. jeanselmei) was sequenced and aligned in view of designing specific padlock probes to be used for the detection of single nucleotide polymorphisms (SNPs) of the Exophiala species concerned. The assay proved to successfully amplify DNA of the target fungi at the level of species; while no cross-reactivity was observed. Amplification products were visualized on 1% agarose gels to verify the specificity of probe-template binding. Amounts of reagents were minimized to avoid the generation of false positive results. The sensitivity of RCA may help to improve early diagnostics of these difficult to diagnose infections.

  • dishwashers a man made ecological niche accommodating human opportunistic fungal pathogens
    Fungal Biology, 2011
    Co-Authors: Polona Zalar, G. S. De Hoog, M Novak, Nina Gundecimerman
    Abstract:

    Habitats in human households may accommodate microorganisms outside the common spectrum of ubiquitous saprobes. Enrichment of fungi that may require specific environmental conditions was observed in dishwashers, 189 of which were sampled in private homes of 101 towns or communities. One-hundred-two were sampled from various localities in Slovenia; 42 from other European countries; 13 and 3 from North and South America, respectively; 5 from Israel; 10 from South Africa; 7 from Far East Asia; and 7 from Australia. Isolation was performed on samples incubated at 37 °C. Species belonging to genera Aspergillus, Candida, Magnusiomyces, Fusarium, Penicillium and Rhodotorula were found occasionally, while the black yeasts Exophiala dermatitidis and Exophiala phaeomuriformis (Chaetothyriales) were persistently and most frequently isolated. Sixty-two percent of the dishwashers were positive for fungi, and 56 % of these accommodated Exophiala. Both Exophiala species are known to be able to cause systemic disease in humans and frequently colonize the lungs of patients with cystic fibrosis. We conclude that high temperature, high moisture and alkaline pH values typically occurring in dishwashers can provide an alternative habitat for species also known to be pathogenic to humans.

  • Exophiala asiatica a new species from a fatal case in china
    Medical Mycology, 2009
    Co-Authors: G. S. De Hoog, Yu Xin Wang, Duan Li Wang
    Abstract:

    We describe a new species, Exophiala asiatica, isolated from an infection of the pharynx in a 20-year-old, immunocompetent woman in Nanjing, China. The infection was initiated by a fishbone prick in the pharynx, soon developed with facial nodules but subsequently seemed to have disappeared. Tonsil ulceration with progressive soreness of the pharynx was observed 3 years later. Dysphagia, headache and paralysis occurred four years after first signs of infection. Hyphae and yeast-like cells were detected in tissue and a black fungus was recovered repeatedly from pharynx tissue. Despite antifungal therapy for more than one year, the patient died of apparent cerebral dissemination of the etiologic agent. On the basis of morphology, nutritional physiology, ribosomal small subunit DNA and ITS sequence data the strain could not be matched with any existing species. A new species, Exophiala asiatica, is therefore proposed.

  • Exophiala spinifera and its allies diagnostics from morphology to dna barcoding
    Medical Mycology, 2008
    Co-Authors: J S Zeng, G. S. De Hoog
    Abstract:

    Diagnostic features of morphology, physiology, serology and genetics of species belonging to the Exophiala spinifera clade (including 11 species: Exophiala oligosperma, E. spinifera, E. xenobiotica, E. jeanselmei, E. Exophialae, E. nishimurae, E. bergeri, E. nigra, Rhinocladiella similis, Ramichloridium basitonum and Phaeoannellomyces elegans), comprising a large number of human-associated Exophiala species, are summarized. Several species have closely similar morphological characters and physiological profiles. Taxonomy is therefore primarily based on sequence diversity of the Internal Transcribed Spacer (ITS) region of ribosomal DNA (rDNA). Multilocus sequencing has shown that ITS is reliable for identification of the species in this clade, and is a therefore a good candidate for barcoding species of Exophiala. Species-specific fragments were searched in the ITS region of species in the Exophiala spinifera clade and can be used to design probes for diagnosis by hybridization.

Nurgul Sasmaz - One of the best experts on this subject based on the ideXlab platform.

Seyedmojtaba Seyedmousavi - One of the best experts on this subject based on the ideXlab platform.

  • atr ftir spectroscopy highlights the problem of distinguishing between Exophiala dermatitidis and e phaeomuriformis using maldi tof ms
    Microbial Ecology, 2016
    Co-Authors: Cagri Ergin, Aylin Dogen, Betil Ozhakbaysan, Dilara Ogunc, Ramazan Gumral, Seyedmojtaba Seyedmousavi, Macit Ilkit, Yasemin Baygu
    Abstract:

    The present study compared two chemical-based methods, namely, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, to understand the misidentification of Exophiala dermatitidis and Exophiala phaeomuriformis. The study utilized 44 E. dermatitidis and 26 E. phaeomuriformis strains, which were partially treated with strong acids and bases for further evaluation. MALDI-TOF MS and ATR-FTIR spectroscopy data of the two Exophiala species were compared. Data groupings were observed for the chromic acid- and nitric acid-treated species when the black yeast sources were categorized as creosoted-oak sleepers, concrete sleepers, or dishwasher isolates. The MALDI-TOF MS data for the metalloenzyme-containing regions were consistent with the ATR-FTIR spectroscopy data. These results indicated that environmental isolates might contain metals not found in human isolates and might interfere with chemical-based identification methods. Therefore, MALDI-TOF MS reference libraries should be created for clinical strains and should exclude petroleum-associated environmental isolates.

Erkin Oztas - One of the best experts on this subject based on the ideXlab platform.

Sybren G De Hoog - One of the best experts on this subject based on the ideXlab platform.

  • comparison of the rolling circle amplification and ligase dependent reaction methods for the identification of opportunistic Exophiala species
    Medical Mycology, 2018
    Co-Authors: Engin Kaplan, Macit Ilkit, Sybren G De Hoog
    Abstract:

    We developed two ligase-dependent probe amplification assays based on rolling circle amplification (RCA) and the ligase-dependent reaction (LDR) to differentiate species of Exophiala targeting the rDNA internal transcribed spacer region. We focused on Exophiala dermatitidis and E. phaeomuriformis, two opportunistic inhabitants of indoor wet cells, and further detected E. heteromorpha, E. xenobiotica, and E. crusticola; 57 reference isolates representing the five species were tested. Depending on the RCA probes used, the sensitivity was 100%, and the specificity ranged from 3.7% to 88.6% (median: 46.1%). In contrast, the sensitivity and specificity of the LDR probes targeting the same isolates were 88.6-100% (median: 95.8%) and 95.4-100% (median: 97.7%), respectively. We analyzed 198 additional environmental isolates representing the same Exophiala species. Overall, the sensitivity and specificity of LDR ranged from 89.7% to 100% (median: 94.1%) and from 93.9% to 100% (median: 96.9%), respectively. The assessment of performance and validation of LDR probes using SYBR Green quantitative polymerase chain reaction revealed high reproducibility and an acceptable range limit, in line with the guidelines of the European Network of GMO Laboratories. In conclusion, the LDR assay was more reliable and less expensive than RCA for species-level identification of Exophiala isolates.

  • in vitro activities of antifungal drugs against environmental Exophiala isolates and review of the literature
    Mycoses, 2018
    Co-Authors: Dolunay Gulmez, Aylin Dogen, Macit Ilkit, Sybren G De Hoog, Ozlem Dogan, Baris Boral, Sevtap Arikanakdagli
    Abstract:

    Exophiala is a genus of black fungi isolated worldwide from environmental and clinical specimens. Data on antifungal susceptibility of Exophiala isolates are limited and the methodology on susceptibility testing is not yet standardised. In this study, we investigated in vitro antifungal susceptibilities of environmental Exophiala isolates. A total of 87 Exophiala isolated from dishwashers or railway ties were included. A CLSI M38-A2 microdilution method with modifications was used to determine antifungal susceptibility for fluconazole, voriconazole, posaconazole, itraconazole, amphotericin B and terbinafine. Minimum inhibitory concentration (MIC) values were determined visually at 48 hours, 72 hours and 96 hours. MIC-0 endpoint (complete inhibition of growth) was used for amphotericin B and azoles, except fluconazole, for which MIC-2 endpoint (~50% inhibition compared to growth control) was used. Both MIC-0 and MIC-1 (~80% inhibition compared to growth control) results were analysed for terbinafine to enable comparison with previous studies. Fungal growth was sufficient for determination of MICs at 48 hours for all isolates except two Exophiala dermatitidis strains. At 72 hours, most active antifungal agents according to GM MIC were voriconazole and terbinafine, followed by posaconazole, itraconazole and amphotericin B in rank order of decreasing activity. While amphotericin B displayed adequate in vitro activity despite relatively high MICs, fluconazole showed no meaningful antifungal activity against Exophiala.

  • nomenclatural notes on nadsoniella and the human opportunist black yeast genus Exophiala
    Mycoses, 2017
    Co-Authors: Tarek A A Moussa, Hassan S Alzahrani, Naif M S Kadasa, Leandro F Moreno, A Gerrits H G Van Den Ende, Sybren G De Hoog, Abdullah M S Alhatmi
    Abstract:

    The opportunistic black yeast are particularly known through the genus Exophiala, characterised by annellidic budding cells. However, this phenotype is polyphyletic within the order Chaetothyriales. Seventeen generic names are available in the family Herpotrichiellaceae, one of which is Exophiala. Future taxonomy will be based on molecular phylogeny; each multi-species clade may qualify for one of these names. This paper focuses on the genus Nadsoniella, which is the oldest valid name in the Herpotrichiellaceae. Despite its Exophiala-like phenotype, the type species of Nadsoniella clusters in the jeanselmei-clade, competing with the sympodial genus Rhinocladiella. In contrast, Exophiala competes with morphologically pronounced genera Thysanorea and Veronaea. Replacing the current phenotypic system for phylogenetic nomenclature requires highly stable phylogenies, which currently are not available.

  • black yeast habitat choices and species spectrum on high altitude creosote treated railway ties
    Fungal Biology, 2013
    Co-Authors: Aylin Dogen, Macit Ilkit, Sybren G De Hoog
    Abstract:

    Polyextremotolerant black yeast-like fungi thrive in moderately hostile environments where they are concomitantly subjected to several types of stress, such as toxicity, scarce nutrient availability, and high or low temperature extremes. Their ability to assimilate alkylbenzenes (toxic environmental pollutants) enhances their growth in harsh conditions, including on railway ties. Samples were collected using cotton swabs, premoistened with physiological saline, from 658 oak and concrete railway ties at six train stations in Turkey at altitudes ranging between 1026 and 1427 m. The samples were inoculated on malt extract agar supplemented with chloramphenicol, and incubated at 26 °C for 4 weeks. Twenty-four samples (3.6 %), 17 from oak and 7 from concrete (5.6 % vs. 2 %; P = 0.02), tested positive for fungi. Exophiala crusticola was found to be the most common species (n = 13), followed by Exophiala phaeomuriformis (n = 7) and Exophiala heteromorpha (n = 4). These results suggest that hydrocarbons, particularly creosote-treated oak woods, support the growth of black yeasts, some of which are opportunists in humans.