Fungicidal Activity of Silver and Silica Nanoparticles against Aspergillus sydowii Isolated from the Soil in Western Saudi Arabia

Aspergillus sydowii is a mesophilic soil saprobe that is a food contaminant as well as a human pathogen in immune-compromised patients. The biological fabrication of silica and silver nanoparticles provides advancements over the chemical approach, as it is eco-friendly and cost-effective. In the present study, Aspergillus sydowii isolates were collected from the soil fields of six different sites in the western area of Saudi Arabia and then identified using the PCR technique following sequencing analysis by BLAST and phylogenetic analysis. Then, applied silica and silver nanoparticles were synthesized by biological methods, using Aspergillus niger as a reducer. Silver and silica nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The antifungal activity of silver and silica nanoparticles against Aspergillus sydowii isolates was evaluated using the disc diffusion method and the minimum inhibitory concentration (MIC). The physiochemical results emphasized the fabrication of silver and silica nanoparticles in spherical shapes with a diameter in the range of 15 and 40 nm, respectively, without any aggregation. MIC of Ag-NPs and Si-NPs against Aspergillus sydowii isolates were 31.25 and 62.5 µg/mL, respectively. Finally, the aim of the study is the use of silver as well as silica nanoparticles as antifungal agents against Aspergillus sydowii.

A F, Sahni RD, Michael JS. Cryptic aspergillosis: a rare entity and a diagnostic challenge

Introduction. Cryptic aspergillosis, caused by cryptic species of Aspergillus, is increasingly reported in humans and causes significant morbidity and mortality in immunocompromised individuals. The main aim of this study was to describe the occurrence of this entity at a large tertiary care centre and analyse the challenges in identifying them in a routine diagnostic laboratory.

Methods. This was a retrospective case review of all patients diagnosed with cryptic Aspergillus species from April 2019 to February 2020. The isolates were identified using conventional microbiological techniques, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI- TOF MS), 28S rRNA and internal transcribed spacer (ITS) sequencing.

Results. The species identified were Aspergillus tamarii, Aspergillus lentulus and Aspergillus sydowii. Identification by MALDI- TOF MS and sequencing was concordant for all except A. sydowii, with MALDI- TOF MS misidentifying it as Aspergillus thermomutans. All isolates showed low minimum inhibitory concentrations (MICs) for the panel of antifungal drugs.

Conclusion. Aspergillosis caused by cryptic Aspergillus species presents a diagnostic challenge. This study confirms the importance of molecular methods for accurate identification.

Characterization and proliferation capacity of potentially pathogenic fungi in marine and freshwater fish commercial feeds

In the aquaculture industry, the selection and quality of feed are highly relevant because their integrity and management have an impact on the health and development of organisms. In general, feeds contamination depends on storage conditions and formulation. Furthermore, it has been recognized that filamentous fungi are among the most important contaminating agent in formulated feeds. Therefore, the purpose of this research was to identify saprophytic fungi capable of proliferating in commercial feeds, as well as determining their prevalence, extracellular enzymes profile, ability to assimilate carbon sources, and finally their ability to produce aflatoxins. In order to do that, twenty-two fungi were isolated from commercial fish feeds. After, the species Aspergillus chevalieri, A. cristatus, A. sydowii, A. versicolor, A. flavus, A. creber, and Lichtheimia ramosa were identified. These fungi were able to produce extracellular enzymes, such as phosphatases, esterases, proteases, β-glucosidase, and N-acetyl-β-glucosaminidase. The isolated fungi showed no selective behavior in the assimilation of the different carbon sources, showing a strong metabolic diversity. Prevalence percentages above 85% were recorded. Among all fungi studied, A. flavus M3-C1 had the highest production of aflatoxins when this strain was inoculated directly in the feeds (295 ppb). The aflatoxin production by this strain under the experimental setting is above the permitted levels, and it has been established that high levels of aflatoxins in feeds can cause alterations in fish growth as well as the development of cancerous tumors in the liver, in addition to enhancing mortality.

Onychomycosis Associated with Superficial Skin Infection Due to Aspergillus sydowii in an Immunocompromised Patient

Opportunistic fungal infections of the skin and nail are frequently encountered in human. Recent years have shown increased incidence of fungal infections especially in immunocompromised patients. Onychomycosis in HIV-infected patients is reported to occur in 15-40%, four times more than in the general population. Here, we report a case of fingernail proximal subungual onychomycosis with associated skin infection caused by an opportunistic mold, Aspergillus sydowii, in a HIV positive individual. Isolation of A. sydowii from nail and skin of an immunocompromised person needs accurate identification for successful treatment.

Another possible risk for the Mediterranean Sea? Aspergillus sydowii discovered in the Port of Genoa (Ligurian Sea, Italy)

Aspergillus sydowii is a cosmopolitan fungus that has been responsible for the mass destruction of coral in the Caribbean Sea over the last 15years. To our knowledge, this study has found the first case of A. sydowii in the Mediterranean Sea, in marine-bottom sediments, water and calcareous shells of bivalve molluscs sampled during a campaign to characterise the mycobiota in the Port of Genoa (Italy). The area is characterised by adverse environmental conditions (high turbidity, organic pollution and high concentrations of phosphorus and nitrogen compounds). These parameters, in combination with a rising temperature, could contribute to A. sydowii bloom and dispersal. This fungal strain may have been imported into the Port of Genoa in the bilge water of vessels or by torrent input. This work represents the first step in the implementation of a monitoring programme to safeguard calcareous sponges and sea fan corals endemic in the Mediterranean Sea.

Aspergillus sydowii and Other Potential Fungal Pathogens in Gorgonian Octocorals of the Ecuadorian Pacific

Emerging fungal diseases are threatening ecosystems and have increased in recent decades. In corals, the prevalence and consequences of these infections have also increased in frequency and severity. Coral reefs are affected by an emerging fungal disease named aspergillosis, caused by Aspergillus sydowii. This disease and its pathogen have been reported along the Caribbean and Pacific coasts of Colombia. Despite this, an important number of coral reefs worldwide have not been investigated for the presence of this pathogen. In this work, we carried out the surveillance of the main coral reef of the Ecuadorian Pacific with a focus on the two most abundant and cosmopolitan species of this ecosystem, Leptogorgia sp. and Leptogorgia obscura. We collected 59 isolates and obtained the corresponding sequences of the Internal Transcribed Spacers (ITS) of the ribosomal DNA. These were phylogenetically analyzed using MrBayes, which indicated the presence of two isolates of the coral reef pathogen A. sydowii, as well as 16 additional species that are potentially pathogenic to corals. Although the analyzed gorgonian specimens appeared healthy, the presence of these pathogens, especially of A. sydowii, alert us to the potential risk to the health and future survival of the Pacific Ecuadorian coral ecosystem under the current scenario of increasing threats and stressors to coral reefs, such as habitat alterations by humans and global climate change.