A Case of Scopulariopsis brevicaulis Endocarditis with Mycotic Aneurysm in an Immunocompetent Host

Native Aortic Valve Endocarditis Caused by Scopulariopsis Species: Case Report, Considerations for Management, and Review of Literature

We present the first case of native aortic valve endocarditis caused by Scopulariopsis. Intraoperative images and videos from valve replacement surgery illustrate the severity of fungal endocarditis. This case demonstrates the aggressive presentation of left-sided fungal endocarditis, highlights challenges with treating highly resistant fungi, and considers the potential utility of olorofim.

Fungal Endocarditis: Pathophysiology, Epidemiology, Clinical Presentation, Diagnosis, and Management

Fungal endocarditis accounts for 1% to 3% of all infective endocarditis cases, is associated with high morbidity and mortality (>70%), and presents numerous challenges during clinical care. Candida spp. are the most common causes of fungal endocarditis, implicated in over 50% of cases, followed by Aspergillus and Histoplasma spp. Important risk factors for fungal endocarditis include prosthetic valves, prior heart surgery, and injection drug use. The signs and symptoms of fungal endocarditis are nonspecific, and a high degree of clinical suspicion coupled with the judicious use of diagnostic tests is required for diagnosis. In addition to microbiological diagnostics (e.g., blood culture for Candida spp. or galactomannan testing and PCR for Aspergillus spp.), echocardiography remains critical for evaluation of potential infective endocarditis, although radionuclide imaging modalities such as 18F-fluorodeoxyglucose positron emission tomography/computed tomography are increasingly being used. A multimodal treatment approach is necessary: surgery is usually required and should be accompanied by long-term systemic antifungal therapy, such as echinocandin therapy for Candida endocarditis or voriconazole therapy for Aspergillus endocarditis.

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.

Current knowledge on the etiology and epidemiology of Scopulariopsis infections

Scopulariopsis is a common fungus in the environment, characterized by its intrinsic resistance to the available antifungal drugs. Around 70 cases of infection by this fungus have been described in the literature. Pulmonary and disseminated infections are the most common and their treatment is difficult; therefore, very diverse approaches have been taken, with varied results. A successful outcome has been reported in only a few cases, generally attributed to a multitreatment strategy combining medical and surgical procedures that ultimately led to the resection of the infected tissue if possible, identification of the mould, and an aggressive long-term antifungal therapy. Although most of the infections are caused by Scopulariopsis brevicaulis, a few other species have also been linked to these cases, although molecular evidence has not been proven for all of them. On this basis, more knowledge on the epidemiology, presentation, diagnosis, treatment, and prognosis of these unusual infections would improve their management. This review aims to compile the current data on Scopulariopsis infections.

In Vitro Inhibiting Effects of Three Fungal Species on Eggs of Donkey Gastrointestinal Strongyles

Recently, donkeys have gained popularity mainly due to the use of donkey milk by the cosmetic industry and for human consumption. Gastrointestinal strongyles (GIS) are considered a potential cause of disease and reduced production in infected donkeys. European laws limit the use of anthelmintic drugs for the control of GIS in dairy donkey farms, thus the need to develop alternative control methods. This study aimed to test the in vitro inhibiting effects of three chitin degrading fungi (Scopulariopsis brevicaulis, Metarhizium anisopliae, and Beauveria bassiana) on the hatch and viability of donkey GIS eggs by using the egg hatch test, and to compare their activity to that of Pochonia chlamydosporia. About 150 eggs were added to 0.5 mL of sterile saline solution containing about 1.4 × 10⁸ spores of each fungal species or with 0.5 mL of sterile saline solution only (untreated controls). After incubation, the percentage of egg hatch reduction was calculated, and data were statistically analyzed. All fungi were able to significantly reduce (p < 0.05) the hatch of GIS eggs compared to the untreated controls. Further studies that aim to investigate the efficiency of these fungi in reducing donkey GIS eggs in contaminated environments are encouraged.

Rapid Assays for Specific Detection of Fungi of Scopulariopsis and Microascus Genera and Scopulariopsis brevicaulis Species

Purpose

Fungi of Scopulariopsis and Microascus genera cause a wide range of infections, with S. brevicaulis being the most prevalent aetiological agent of mould onychomycosis. Proper identification of these pathogens requires sporulating culture, which considerably delays the diagnosis. So far, sequencing of rDNA regions of clinical isolates has produced ambiguous results due to the lack of reference sequences in publicly available databases. Thus, there is a clear need for the development of new molecular methods that would provide simple, rapid and highly specific identification of Scopulariopsis and Microascus species. The objective of this study was to develop simple and fast assays based on PCR and real-time PCR for specific detection of fungi from Scopulariopsis and Microascus genera, and separately, S. brevicaulis species.

Methods

On the basis of alignment of β-tubulin gene sequences, Microascus/Scopulariopsis-specific primers were designed and S. brevicaulis-specific primers were reevaluated. DNA from cultured fungal isolates, extracted in a two-step procedure, was used in Microascus/Scopulariopsis-specific and S. brevicaulis-specific PCR and real-time PCR followed by electrophoresis or melting temperature analysis, respectively.

Results

The specificity of the assays was confirmed, as positive results were obtained only for Scopulariopsis spp. and Microascus spp. isolates tested in Microascus/Scopulariopsis-specific assay, and only for S. brevicaulis and S. koningii (syn. S. brevicaulis) isolates in a S. brevicaulis-specific assay, respectively, and no positive results were obtained neither for other moulds, dermatophytes, yeast-like fungi, nor for human DNA.

Conclusions

The developed assays enable fast and unambiguous identification of Microascus spp. and Scopulariopsis spp. pathogens.

Virulence and Resistance to Antifungal Therapies of Scopulariopsis Species

Scopulariopsisis an emerging opportunistic fungus characterized by its high resistance to antifungal therapies. We have developed a murine model of disseminated infection in immunosuppressed animals by intravenous inoculation ofScopulariopsis brevicaulisandScopulariopsis brumptii, the most clinically relevant species, in order to evaluate their virulence and their responses to conventional antifungal treatments. Survival and tissue burden studies showed thatS. brumptiiwas more virulent thanS. brevicaulis The three drugs tested, liposomal amphotericin B, posaconazole, and voriconazole, prolonged the survival of mice infected withS. brumptii, but none showed efficacy againstS. brevicaulis The different therapies were only able to modestly reduce the fungal burden of infected tissue; however, in general, despite the high serum levels reached, they showed poor efficacy in the treatment of the infection. Unfortunately, the most effective therapy forScopulariopsisinfections remains unresolved.