The Synergistic Effect of Tacrolimus (FK506) or Everolimus and Azoles Against Scedosporium and Lomentospora Species In Vivo and In Vitro

Scedosporium species and Lomentospora prolificans fungaemia is uniformly fatal in patients with haematological malignancy

Scedosporium and Lomentospora species are environmental moulds that are virulent in immunocompromised hosts and rarely cause bloodstream infection (BSI). Patients with Scedosporium and Lomentospora species BSI were identified by the state public laboratory service in Queensland, Australia, over a 20-year period. Twenty-two incident episodes occurred among 21 residents; one patient had a second episode 321 days following the first. Of these, 18 were Lomentospora prolificans, three were Scedosporium apiospermum complex and one was a nonspeciated Scedosporium species. Seventeen (81%) patients died during their index admission, and all-cause mortality at 30, 90 and 365 days was 73%, 82% and 91% respectively. All 20 patients with haematological malignancy died within 365 days of follow-up with a median time to death of 9 days (interquartile range, 6-20 days) following diagnoses of BSI.

In Vitro and In Vivo Evaluation of Synergistic Effects of Everolimus in Combination with Antifungal Agents on Exophiala dermatitidis

To investigate the combined function of the novel oral mTOR inhibitor, everolimus, with antifungal agents and their potential mechanisms against Exophiala dermatitidis, the CLSI microliquid-based dilution method M38-A2, chequerboard technique, and disk diffusion testing were performed. The efficacy of everolimus was evaluated in combination with itraconazole, voriconazole, posaconazole, and amphotericin B against 16 clinically isolated strains of E. dermatitidis. The synergistic effect was determined by measuring the MIC and fractional inhibitory concentration index. Dihydrorhodamine 123 was used for the quantification of ROS levels. The differences in the expression of antifungal susceptibility-associated genes were analyzed following different types of treatment. Galleria mellonella was used as the in vivo model. While everolimus alone showed minimal antifungal effects, combinations with itraconazole, voriconazole, posaconazole, or amphotericin B resulted in synergy in 13/16 (81.25%), 2/16 (12.5%), 14/16 (87.75%), and 5/16 (31.25%) of isolates, respectively. The disk diffusion assay revealed that the combination of everolimus and antifungal drugs showed no significant increase in the inhibition zones compared with the single agent, but no antagonistic effects were observed. Combination of everolimus and antifungal agents resulted in increased ROS activity (everolimus + posaconazole versus posaconazole [P < 0.05], everolimus + amphotericin B versus amphotericin B [P < 0.002]). Simultaneously, compared to mono-treatment, the combination of everolimus + itraconazole suppressed the expression of MDR2 (P < 0.05) and the combination of everolimus + amphotericin B suppressed the expression of MDR3 (P < 0.05) and CDR1B (P < 0.02). In vivo, combinations of everolimus and antifungal agents improved survival rates, particularly the combination of everolimus + amphotericin B (P < 0.05). In summary, the in vivo and in vitro experiments performed in our study suggest that the combination of everolimus with azoles or amphotericin B can have synergistic effects against E. dermatitidis, potentially due to the induction of ROS activity and inhibition of efflux pumps, providing a promising new approach for the treatment of E. dermatitidis infections. IMPORTANCE Cancer patients with E. dermatitidis infection have high mortality if untreated. Clinically, the conventional treatment of E. dermatitidis is poor due to the long-term use of antifungal drugs. In this study, we have for the first time investigated the interaction and action mechanism of everolimus combined with itraconazole, voriconazole, posaconazole, and amphotericin B on E. dermatitidis in vitro and in vivo, which provided new ideas and direction for further exploring the mechanism of drug combination and clinical treatment of E. dermatitidis.

Combined Application of Tacrolimus with Cyproconazole, Hymexazol and Novel {2-(3-R-1H-1,2,4-triazol-5-yl)phenyl}amines as Antifungals: In Vitro Growth Inhibition and In Silico Molecular Docking Analysis to Fungal Chitin Deacetylase

Agents with antifungal activity play a vital role as therapeutics in health care, as do fungicides in agriculture. Effectiveness, toxicological profile, and eco-friendliness are among the properties used to select suitable substances. Furthermore, a steady supply of new agents with different modes of action is required to counter the well-known potential of human and phyto-pathogenic fungi to develop resistance against established antifungals. Here, we use an in vitro growth assay to investigate the activity of the calcineurin inhibitor tacrolimus in combination with the commercial fungicides cyproconazole and hymexazol, as well as with two earlier reported novel {2-(3-R-1H-1,2,4-triazol-5-yl)phenyl}amines, against the fungi Aspergillus niger, Colletotrichum higginsianum, Fusarium oxysporum and the oomycete Phytophthora infestans, which are notoriously harmful in agriculture. When tacrolimus was added in a concentration range from 0.25 to 25 mg/L to the tested antifungals (at a fixed concentration of 25 or 50 mg/L), the inhibitory activities were distinctly enhanced. Molecular docking calculations revealed triazole derivative 5, (2-(3-adamantan-1-yl)-1H-1,2,4-triazol-5-yl)-4-chloroaniline), as a potent inhibitor of chitin deacetylases (CDA) of Aspergillus nidulans and A. niger (AnCDA and AngCDA, respectively), which was stronger than the previously reported polyoxorin D, J075-4187, and chitotriose. The results are discussed in the context of potential synergism and molecular mode of action.

Analysis of the synergistic antifungal activity of everolimus and antifungal drugs against dematiaceous fungi

Introduction

Chromoblastomycosis (CBM) is a form of chronic mycosis that affects the skin and mucous membranes and is caused by species of dematiaceous fungi including Exophiala spp., Phialophora spp., and Fonsecaea spp. The persistence of this disease and limitations associated with single-drug treatment have complicated efforts to adequately manage this condition.

Methods

In this study, a microdilution assay was used to explore the synergistic antifungal activity of everolimus (EVL) in combination with itraconazole (ITC), voriconazole (VRC), posaconazole (POS), and amphotericin B (AMB) against a range of clinical dematiaceous fungal isolates.

Results

These analyses revealed that the EVL+POS and EVL+ITC exhibited superior in vitro synergistic efficacy, respectively inhibiting the growth of 64% (14/22) and 59% (13/22) of tested strains. In contrast, the growth of just 9% (2/22) of tested strains was inhibited by a combination of EVL+AMB, and no synergistic efficacy was observed for the combination of EVL+VRC.

Discussion

Overall, these findings indicate that EVL holds promise as a novel drug that can be synergistically combined with extant antifungal drugs to improve their efficacy, thereby aiding in the treatment of CBM.

Case report: Disseminated Scedosporium apiospermum infection with invasive right atrial mass in a heart transplant patient

Scedosporium apiospermum associated endocarditis is extremely rare. We report a case of a disseminated S. apiospermum infection with an invasive right atrial mass in a 52-year-old male, 11 months after heart transplantation, referred to our institution for an endogenous endophthalmitis with a one-month history of diffuse myalgias and fatigue. The patient had been supported two times with extracorporeal membrane oxygenation (ECMO) during the first three postoperative months. The echocardiography on admission revealed a mass in the right atrium attached to a thickened lateral wall. The whole-body [18F]FDG PET/CT revealed systemic dissemination in the lungs, muscles, and subcutaneous tissue. Blood cultures were positive on day three for filamentous fungi later identified as S. apiospermum. The disease was refractory to a 3-week dual antifungal therapy with voriconazole and anidulafungin in addition to reduced immunosuppression, and palliative care was implemented.