Mucor germinans, a novel dimorphic species resembling Paracoccidioides in a clinical sample: questions on ecological strategy.

Dimorphism is known among the etiologic agents of endemic mycoses as well as in filamentous Mucorales. Under appropriate thermal conditions, mononuclear yeast forms alternate with multi-nucleate hyphae. Here, we describe a dimorphic mucoralean fungus obtained from the sputum of a patient with Burkitt lymphoma and ongoing graft-versus-host reactions. The fungus is described as Mucor germinans sp. nov. Laboratory studies were performed to simulate temperature-dependent dimorphism, with two environmental strains Mucor circinelloides and Mucor kunryangriensis as controls. Both strains could be induced to form multinucleate arthrospores and subsequent yeast-like cells in vitro. Multilateral yeast cells emerge in all three Mucor species at elevated temperatures. This morphological transformation appears to occur at body temperature since the yeast-like cells were observed in the lungs of our immunocompromised patient. The microscopic appearance of the yeast-like cells in the clinical samples is easily confused with that of Paracoccidioides. The ecological role of yeast forms in Mucorales is discussed.IMPORTANCEMucormycosis is a devastating disease with high morbidity and mortality in susceptible patients. Accurate diagnosis is required for timely clinical management since antifungal susceptibility differs between species. Irregular hyphal elements are usually taken as the hallmark of mucormycosis, but here, we show that some species may also produce yeast-like cells, potentially being mistaken for Candida or Paracoccidioides. We demonstrate that the dimorphic transition is common in Mucor species and can be driven by many factors. The multi-nucleate yeast-like cells provide an effective parameter to distinguish mucoralean infections from similar yeast-like species in clinical samples.

In Vitro Antifungal Susceptibility Profiles of 12 Antifungal Drugs against 55 Trichophyton schoenleinii Isolates from Tinea Capitis Favosa Patients in Iran, Turkey, and China.

Trichophyton schoenleinii is an anthropophilic dermatophyte mainly causing tinea favosa of the scalp in certain regions of the world, especially Africa and Asia. We investigated the in vitro susceptibilities of 55 T. schoenleinii isolates collected over the last 30 years from Iran, Turkey, and China to 12 antifungals using the CLSI broth microdilution method. Our results revealed that terbinafine and ketoconazole were the most potent antifungal agents among those tested, independently of the geographic regions where strains were isolated.

Systemic Antifungal Agents: Current Status and Projected Future Developments.

By definition, an antifungal agent is a drug that selectively destroys fungal pathogens with minimal side effects to the host. Despite an increase in the prevalence of fungal infections particularly in immunocompromised patients, only a few classes of antifungal drugs are available for therapy, and they exhibit limited efficacy in the treatment of life-threatening infections. These drugs include polyenes, azoles, echinocandins, and nucleoside analogs. This chapter focuses on the currently available classes and representatives of systemic antifungal drugs in clinical use. We further discuss the unmet clinical needs in the antifungal research field; efforts in reformulation of available drugs such as Amphotericin B nanoparticles for oral drug delivery; development of new agents of known antifungal drug classes, such as albaconazole, SCY-078, and biafungin; and new drugs with novel targets for treatment of invasive fungal infections, including nikkomycin Z, sordarin derivatives, VT-1161 and VT-1129, F901318, VL-2397, and T-2307.

Topical and systemic antifungals in dermatology practice.

INTRODUCTION: Dermatophytosis is generally defined as an infection of the hair, nails, or glabrous skin. These infections are caused by the keratinophilic fungi Trichophyton spp., Microsporum spp., and Epidermophyton, which have been recovered from both symptomatic and asymptomatic individuals. Although dermatophytosis is generally not a life-threatening condition, these types of infections are among the most common infections worldwide, and their incidence has continued to increase consistently in recent years. Area covered: This article provides an overview of the general characteristics of dermatophytes, including their taxonomy and epidemiology, as well as the different clinical forms and laboratory diagnostics of dermatophytosis. We further classify the topical and systemic antifungal compounds currently used to treat dermatophyte infections. Expert commentary: Antifungal therapy is a central component of patient management for dermatophytosis, and depending on the strategy chosen, topical and/or systemic drugs can be used. However, for effective treatment, it is important to correctly determine the causal agents at the species level, which will enable administration of suitable therapeutics and initiation of appropriate management strategies.

Discrimination of Aspergillosis, Mucormycosis, Fusariosis, and Scedosporiosis in Formalin-Fixed Paraffin-Embedded Tissue Specimens by Use of Multiple Real-Time Quantitative PCR Assays.

In a retrospective multicenter study, 102 formalin-fixed paraffin-embedded (FFPE) tissue specimens with histopathology results were tested. Two 4- to 5-µm FFPE tissue sections from each specimen were digested with proteinase K, followed by automated nucleic acid extraction. Multiple real-time quantitative PCR (qPCR) assays targeting the internal transcribed spacer 2 (ITS2) region of ribosomal DNA, using fluorescently labeled primers, was performed to identify clinically important genera and species of Aspergillus, Fusarium, Scedosporium, and the Mucormycetes The molecular identification was correlated with results from histological examination. One of the main findings of our study was the high sensitivity of the automated DNA extraction method, which was estimated to be 94%. The qPCR procedure that was evaluated identified a range of fungal genera/species, including Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus, Aspergillus niger, Fusarium oxysporum, Fusarium solani, Scedosporium apiospermum, Rhizopus oryzae, Rhizopus microsporus, Mucor spp., and Syncephalastrum Fusarium oxysporum and F. solani DNA was amplified from five specimens from patients initially diagnosed by histopathology as having aspergillosis. Aspergillus flavus, S. apiospermum, and Syncephalastrum were detected from histopathological mucormycosis samples. In addition, examination of four samples from patients suspected of having concomitant aspergillosis and mucormycosis infections resulted in the identification of two A. flavus isolates, one Mucor isolate, and only one sample having both R. oryzae and A. flavus Our results indicate that histopathological features of molds may be easily confused in tissue sections. The qPCR assay used in this study is a reliable tool for the rapid and accurate identification of fungal pathogens to the genus and species levels directly from FFPE tissues.

Quantitative Analysis of Single-Nucleotide Polymorphism for Rapid Detection of TR34/L98H- and TR46/Y121F/T289A-Positive Aspergillus fumigatus Isolates Obtained from Patients in Iran from 2010 to 2014.

We employed an endpoint genotyping method to update the prevalence rate of positivity for the TR34/L98H mutation (a 34-bp tandem repeat mutation in the promoter region of the cyp51A gene in combination with a substitution at codon L98) and the TR46/Y121F/T289A mutation (a 46-bp tandem repeat mutation in the promoter region of the cyp51A gene in combination with substitutions at codons Y121 and T289) among clinical Aspergillus fumigatus isolates obtained from different regions of Iran over a recent 5-year period (2010 to 2014). The antifungal activities of itraconazole, voriconazole, and posaconazole against 172 clinical A. fumigatus isolates were investigated using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. For the isolates with an azole resistance phenotype, the cyp51A gene and its promoter were amplified and sequenced. In addition, using a LightCycler 480 real-time PCR system, a novel endpoint genotyping analysis method targeting single-nucleotide polymorphisms was evaluated to detect the L98H and Y121F mutations in the cyp51A gene of all isolates. Of the 172 A. fumigatus isolates tested, the MIC values of itraconazole (≥16 mg/liter) and voriconazole (>4 mg/liter) were high for 6 (3.5%). Quantitative analysis of single-nucleotide polymorphisms showed the TR34/L98H mutation in the cyp51A genes of six isolates. No isolates harboring the TR46/Y121F/T289A mutation were detected. DNA sequencing of the cyp51A gene confirmed the results of the novel endpoint genotyping method. By microsatellite typing, all of the azole-resistant isolates had genotypes different from those previously recovered from Iran and from the Dutch TR34/L98H controls. In conclusion, there was not a significant increase in the prevalence of azole-resistant A. fumigatus isolates harboring the TR34/L98H resistance mechanism among isolates recovered over a recent 5-year period (2010 to 2014) in Iran. A quantitative assay detecting a single-nucleotide polymorphism in the cyp51A gene of A. fumigatus is a reliable tool for the rapid screening and monitoring of TR34/L98H- and TR46/Y121F/T289A-positive isolates and can easily be incorporated into clinical mycology algorithms.

Genotyping of Clostridium perfringens isolated from healthy and diseased ostriches (Struthio camelus).

BACKGROUND AND OBJECTIVES: Clostridium perfringens is more prevalent type of clostridia genus isolated from the intestinal tract of ostrich (Struthio camelus). Necrotic enteritis (NE) is a potentially fatal gastrointestinal (GI) disease of poultry and other avian species, which produces marked destruction of intestinal lining in digestive tract caused by C. perfringens. Pathogenicity and lesions are correlated with the toxins produced, thus toxin typing of the bacterium has diagnostic and epidemiological significance. The aims of the present study were to determine the biotypes of C. perfringens among ostrich's farms either diseased and healthy ones and to screen the isolates for major toxin genes (cpa, cpb, etx, and iA, cpb2, and cpe). MATERIALS AND METHODS: Thirty isolates of C. perfringens were obtained from NE-positive and NE-negative ostrich flocks in Khorasan-e-Razavi porvince and analyzed by multiplex PCR assay. RESULTS: All isolates were positive for alpha toxin gene (cpa) and five of those were positive for beta toxin gene (cpb). The presence of cpb2 gene was detected in a high percentage of isolates originating from both healthy (93.3%) and diseased flocks (80%). None of the isolate carried enterotoxin gene (cpe). CONCLUSION: The results suggest that types A and C of C. perfringens are the most prevalent types in ostrich in Iran. Due to detection of beta2 toxin gene in isolates from both healthy and diseased birds, it appears that the presence of cpb2 is not considered a risk by itself.