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Anecdotal clinical reports suggested a benefit of adjunct immune checkpoint inhibitors (ICIs) to treat invasive mucormycosis. However, proof-of-concept data in animal models and mechanistic insights into the effects of ICIs on host defense against Mucorales are lacking. Therefore, we studied the effects of PD-1 and PD-L1 inhibitors (4 doses of 250 µg/kg) on outcomes and immunopathology of invasive pulmonary mucormycosis (IPM) in cyclophosphamide- and cortisone acetate-immunosuppressed mice. Rhizopus arrhizus -infected mice receiving either of the ICI treatments had significantly improved survival, less morbidity, and lower fungal burden compared to isotype-treated infected mice. While early improvement of morbidity/mortality was comparable between the ICI treatments, anti-PD-L1 provided more consistent sustained protection through day 7 post-infection than anti-PD-1. Both ICIs enhanced the fungicidal activity of ex-vivo splenocytes and effectively counteracted T-cell exhaustion; however, macrophages of ICI-treated mice showed compensatory upregulation of other checkpoint markers. Anti-PD-1 elicited stronger pulmonary release of proinflammatory cytokines and chemokines than anti-PD-L1, but also induced cytokines associated with potentially unfavorable type 2 T-helper-cell and regulatory T-cell responses. Although no signs of hyperinflammatory toxicity were observed, mice with IPM receiving ICIs, particularly anti-PD-1, had elevated serum levels of IL-6, a cytokine linked to ICI toxicities. Altogether, inhibition of the PD-1/PD-L1 pathway improved clinical outcomes of IPM in immunosuppressed mice, even without concomitant antifungals. PD-L1 inhibition yielded more favorable immune responses and more consistent protection from IPM-associated morbidity and mortality than PD-1 blockade. Future dose-effect studies are needed to define the "sweet spot" between ICI-induced augmentation of antifungal immunity and potential immunotoxicities., Competing Interests: DK reports honoraria and research support from Gilead Sciences and Astellas Pharma. He received consultant fees from Astellas Pharma, Merck, and Gilead Sciences, and is a member of the Data Review Committee of Cidara Therapeutics, AbbVie, Scynexis, and the Mycoses Study Group. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wurster, Albert, Bharadwaj, Kasembeli, Tarrand, Daver and Kontoyiannis.)

Background: Mucormycosis is a destructive invasive mold infection afflicting patients with diabetes and hematologic malignancies. Patients with diabetes are often treated with statins, which have been shown to have antifungal properties. We sought to examine the effects of statins on Rhizopus oryzae, a common cause of mucormycosis., Methods: Clinical strains of R. oryzae were exposed to lovastatin, atorvastatin, and simvastatin and the minimum inhibitory concentrations (MICs) were determined. R. oryzae germination, DNA fragmentation, susceptibility to oxidative stress, and ability to damage endothelial cells were assessed. We further investigated the impact of exposure to lovastatin on the virulence of R. oryzae, Results: All statins had MICs of >64 µg/mL against R. oryzae Exposure of R. oryzae to statins decreased germling formation, induced DNA fragmentation, and attenuated damage to endothelial cells independently of the expression of GRP78 and CotH. Additionally, R. oryzae exposed to lovastatin showed macroscopic loss of melanin, yielded increased susceptibility to the oxidative agent peroxide, and had attenuated virulence in both fly and mouse models of mucormycosis., Conclusions: Exposure of R. oryzae to statins at concentrations below their MICs decreased virulence both in vitro and in vivo. Further investigation is warranted into the use of statins as adjunctive therapy in mucormycosis., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)

We used two established neutropenic murine models of pulmonary aspergillosis and mucormycosis to explore the association between the posaconazole area under the concentration-time curve (AUC)-to-MIC ratio (AUC/MIC) and treatment outcome. Posaconazole serum pharmacokinetics were verified in infected mice to ensure that the studied doses reflected human exposures with the oral suspension, delayed-release tablet, and intravenous formulations of posaconazole. Sinopulmonary infections were then induced in groups of neutropenic mice with Aspergillus fumigatus strain 293 (posaconazole MIC, 0.5 mg/liter) or Rhizopus oryzae strain 969 (posaconazole MIC, 2 mg/liter) and treated with escalating daily dosages of oral posaconazole, which was designed to achieve AUCs ranging from 1.10 to 392 mg · h/liter. After 5 days of treatment, lung fungal burden was analyzed by quantitative real-time PCR. The relationships of the total drug AUC/MIC and the treatment response were similar in both models, with 90% effective concentrations (EC90s) corresponding to an AUC/MIC threshold of 76 (95% confidence interval [CI], 46 to 102) for strain 293 versus 87 (95% CI, 66 to 101) for strain 969. Using a provisional AUC/MIC target of >100, these exposures correlated with minimum serum posaconazole concentrations (Cmins) of 1.25 mg/liter for strain 293 and 4.0 mg/liter for strain 969. The addition of deferasirox, but not liposomal amphotericin or caspofungin, improved the activity of a suboptimal posaconazole regimen (AUC/MIC, 33) in animals with pulmonary mucormycosis. However, no combination was as effective as the high-dose posaconazole monotherapy regimen (AUC/MIC, 184). Our analysis suggests that posaconazole pharmacodynamics are similar for A. fumigatus and R. oryzae when indexed to pathogen MICs., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

Background Myocutaneous mucormycosis is encountered in settings of extreme mechanical forces such as combat-related blast injuries or natural catastrophes. It is unclear whether the virulence of Mucorales is affected by mechano-biological factors such as shear forces (SF). Methods Spores of clinical strains of Rhizopus arrhizus , Rhizomucor pusillus , and Mucor circinelloides (107/mL in PBS) were either kept in static culture (control) or exposed to shear forces (SF) by magnetic stirring for 30 minutes. Mycelial expansion was monitored in the IncuCyte time-lapse microscopy system. For in vivo studies, the dorsal thorax of wild-type Drosophila melanogaster flies (n = 66–76 per condition) was pricked with a needle dipped in control or SF-exposed spore solutions. Flies were also infected with non-exposed spores suspended in cell-free supernatant taken from SF-exposed spores. Survival was monitored for 7 days post-infection. Results Growth rates and morphogenesis of all isolates were not altered by SF. However, SF-exposed spores of all tested Mucorales isolates exhibited increased pathogenicity in the fly model (7-day survival: SF 8–14%, control 36–44%, P < 0.001). Introducing different resting periods after SF resulted in gradual attenuation of the hyper-virulent phenotype, with survival rates of infected flies returning to the level seen with non-SF-exposed spores after 120 min post-SF resting (Panel A). To gain a mechanistic insight, we added cyclosporine A (CsA, 100 µg/mL) during shear challenge. Compared with SF-exposed spores, CsA addition improved 7-day survival of R. arrhizus -infected flies from 1% to 29% (P < 0.001), whereas the pathogenicity of non-SF-exposed spores was not influenced by CsA. Interestingly, supernatants from SF-exposed R. arrhizus rendered non-exposed spores hyper-virulent (Panel B, P = 0.003). Conclusion SF induces a transient hypervirulent phenotype of Mucorales. Our findings suggest that soluble mediators contribute to increased pathogenicity. Largely attenuated hyper-virulence in the presence of CsA corroborated the previously described relevance of the calcineurin pathway in fungal mechano-biology. RNA sequencing studies are in progress to identify epigenetic alterations in Mucorales following SF. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

We compared the in vitro pharmacodynamics of isavuconazole, voriconazole, and posaconazole against 92 clinical isolates from documented cases of invasive aspergillosis, mucormycosis, fusariosis, and phaeohyphomycosis. Whereas inhibitory and fungicidal concentrations of these triazoles were predictably similar with the exception of Mucorales , isavuconazole appeared to have improved pharmacodynamics against Fusarium solani. [ABSTRACT FROM AUTHOR]