Current knowledge on the etiology and epidemiology of Scopulariopsis infections

Studies on Antifungal Properties of Methacrylamido Propyl Trimethyl Ammonium Chloride Polycations and Their Toxicity In Vitro

The biological activity of polycations is usually associated with their biocidal properties. Their antibacterial features are well known, but in this work, observations on the antifungal properties of macromolecules obtained by methacrylamido propyl trimethyl ammonium chloride (MAPTAC) polymerization are presented. The results, not previously reported, make it possible to correlate antifungal properties directly with the structure of the macromolecule, in particular the molecular mass. The polymers described here have antifungal activity against some filamentous fungi. The strongest effect occurs for polymers with a mass of about 0.5 mDa which have confirmed activity against the multidrug-resistant species Scopulariopsis brevicaulis, Fusarium oxysporum, and Fusarium solani, as well as the dermatophytes Trichophyton mentagrophytes, Trichophyton rubrum, Trichophyton interdigitale, and Trichophyton tonsurans. In addition, this publication describes the effects of these macromolecular systems on serum and blood components and provides a preliminary assessment of toxicity on cell lines of skin-forming cells, i.e., fibroblasts and keratinocytes. Additionally, using a Franz diffusion chamber, a negligibly low transport of the active polymer through the skin was demonstrated, which is a desirable effect for externally applied antifungal drugs. IMPORTANCE Infectious diseases are a very big medical, social, and economic problem. Even before the COVID-19 pandemic, certain infections were among of the most common causes of death. The difficulties in the treatment of infectious diseases concern in particular fungal diseases, against which we have only a few classes of drugs represented by a few substances. The publication presents the preliminary results of the in vitro antifungal activity studies of four MAPTAC polymers on different fungal species and their cytotoxicity to human cells (fibroblasts and keratinocytes). The paper also compares these properties with analogous ones of two commonly used antifungal drugs, ciclopirox and terbinafine.

Discovery of entomopathogenic fungi across geographical regions in southern China on pine sawyer beetle Monochamus alternatus and implication for multi-pathogen vectoring potential of this beetle

Entomopathogen-based biocontrol is crucial for blocking the transmission of vector-borne diseases; however, few cross-latitudinal investigations of entomopathogens have been reported for vectors transmitting woody plant diseases in forest ecosystems. The pine sawyer beetle Monochamus alternatus is an important wood borer and a major vector transmitting pine wilt disease, facilitating invasion of the pinewood nematode Bursaphelenchus xylophilus (PWN) in China. Due to the limited geographical breadth of sampling regions, species diversity of fungal associates (especially entomopathogenic fungi) on M. alternatus adults and their potential ecological functions have been markedly underestimated. In this study, through traditional fungal isolation with morphological and molecular identification, 640 fungal strains (affiliated with 15 genera and 39 species) were isolated from 81 beetle cadavers covered by mycelia or those symptomatically alive across five regional populations of this pest in southern China. Multivariate analyses revealed significant differences in the fungal community composition among geographical populations of M. alternatus, presenting regionalized characteristics, whereas no significant differences were found in fungal composition between beetle genders or among body positions. Four region-representative fungi, namely, Lecanicillium attenuatum (Zhejiang), Aspergillus austwickii (Sichuan), Scopulariopsis alboflavescens (Fujian), and A. ruber (Guangxi), as well as the three fungal species Beauveria bassiana, Penicillium citrinum, and Trichoderma dorotheae, showed significantly stronger entomopathogenic activities than other fungi. Additionally, insect-parasitic entomopathogenic fungi (A. austwickii, B. bassiana, L. attenuatum, and S. alboflavescens) exhibited less to no obvious phytopathogenic activities on the host pine Pinus massoniana, whereas P. citrinum, Purpureocillium lilacinum, and certain species of Fusarium spp.-isolated from M. alternatus body surfaces-exhibited remarkably higher phytopathogenicity. Our results provide a broader view of the entomopathogenic fungal community on the vector beetle M. alternatus, some of which are reported for the first time on Monochamus spp. in China. Moreover, this beetle might be more highly-risk in pine forests than previously considered, as a potential multi-pathogen vector of both PWN and phytopathogenic fungi.

Preliminary Studies on the Mechanism of Antifungal Activity of New Cationic β-Glucan Derivatives Obtained from Oats and Barley

New chemical structures with antifungal properties are highly desirable from the point of view of modern pharmaceutical science, especially due to the increasingly widespread instances of drug resistance in the case of these diseases. One way to solve this problem is to use polymeric drugs, widely described as biocidal, positively charged macromolecules. In this work, we present the synthesis of new cationic β-glucan derivatives that show selective antifungal activity and at the same time low toxicity toward animal and human cells. Two β-glucans isolated from oats and barley and modified using glycidyltrimethylammonium chloride were obtained and evaluated for biocidal properties on the cells of mammals and pathogenic fungi and bacteria. These compounds were found to be nontoxic to fibroblast and bacterial cells but showed selective toxicity to certain species of filamentous fungi (Scopulariopsis brevicaulis) and yeasts (Cryptococcus neoformans). The most important aspect of this work is the attempt to explain the mechanisms of action of these compounds by studying their interaction with biological membranes. This was achieved by examining the interactions with model biological membranes representative of given families of microorganisms using Langmuir monolayers. The data obtained partly show correlations between the results for model systems and biological experiments and allow indicating that the selective antifungal activity of cationic β-glucans is related to their interaction with fungal biological membranes and partly lack of such interaction toward cells of other organisms. In addition, the obtained macromolecules were characterized by spectral methods (Fourier transform infrared (FTIR) and ¹H nuclear magnetic resonance (NMR) spectroscopies) to confirm that the desired structure was obtained, and their degree of modification and molecular weights were determined.

Performance of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Identification of Scedosporium, Acremonium-Like, Scopulariopsis, and Microascus Species

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a powerful microorganism identification tool. Research on MALDI-TOF MS identification of rare filamentous fungi is still lacking. This study aimed to evaluate the performance of MALDI-TOF MS in the identification of Scedosporium, Acremonium-like, Scopulariopsis, and Microascus species. Sabouraud broth cultivation and formic acid/acetonitrile protein extraction were used for MALDI-TOF MS identification by a Bruker Biotyper system. An in-house database containing 29 isolates of Scedosporium, Acremonium-like, Scopulariopsis, and Microascus spp. was constructed. A total of 52 clinical isolates were identified using the Bruker Filamentous Fungi Library v1.0 (FFL v1.0) alone, and Filamentous Fungi Library v1.0 plus the in-house library, respectively. The mass spectrum profile (MSP) dendrograms of the 28 Scedosporium isolates, 26 Acremonium-like isolates, and 27 Scopulariopsis and Microascus isolates were constructed by MALDI Biotyper OC 4.0 software, respectively. The correct species identification rate significantly improved when using the combined databases compared with that when using FFL v1.0 alone (Scedosporium spp., 75% versus 0%; Acremonium-like spp., 100% versus 0%; Scopulariopsis and Microascus spp., 100% versus 62.5%). The MSP dendrograms differentiated Acremonium-like species, Scopulariopsis and Microascus species clearly, but cannot distinguish species in the Scedosporium apiospermum complex. In conclusion, with an expanded database, MALDI-TOF MS is an effective tool for the identification of Scedosporium, Acremonium-like, Scopulariopsis, and Microascus species.

Pulmonary Microascus cirrosus infection in an immunocompetent patient with bronchiectasis: A case report

Microascus species are widely distributed and rarely cause invasive infection in humans. Here we report a case of lung Microascus cirrosus infection in an immunocompetent patient with bronchiectasis. While on systemic voriconazole and aerosolized amphotericin B for three months, the patient's overall condition improved. This case report highlights the possibility of rare pathogen infection occurred in a bronchiectasis patient, as well as the importance of accurate diagnosis and individualized therapy of pulmonary Microascus infection.

Nebulized Micafungin Treatment for Scopulariopsis/Microascus Tracheobronchitis in Lung Transplant Recipients

Scopulariopsis/Microascus isolates cause infections with high mortality in lung transplant recipients. Treatment is challenging due to antimicrobial resistance. We describe two cases of Scopulariopsis/Microascus tracheobronchitis in lung transplant recipients successfully treated with nebulized micafungin. This antifungal was well tolerated and achieved high concentrations in epithelial lining fluid up to 14 h after nebulization without significant plasma concentrations. Nebulized micafungin may be a safe and effective option for the treatment of fungal tracheobronchitis.