Systemic Antifungal Agents: Current Status and Projected Future Developments

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Using an immunocompetent murine model of invasive aspergillosis (IA), we previously reported that the efficacy of liposomal amphotericin B (L-AmB) (Ambisome) is not hampered by the presence of azole resistance mutations in Aspergillus fumigatus (S. Seyedmousavi, W. J. G. Melchers, J. W. Mouton, and P. E. Verweij, Antimicrob Agents Chemother 57:1866 -1871, 2013, https://doi.org/10.1128/AAC.02226 -12). We here investigated the role of immune suppression, i.e., neutropenia and steroid treatment, in L-AmB efficacy in mice infected with wild-type (WT) A. fumigatus and with azole-resistant A. fumigatus harboring a TR 34 /L98H mutation in the cyp-51A gene. Survival of treated animals at day 14 in both immunosuppressed models was significantly better than that of nontreated controls. A dose-response relationship was observed that was independent of the azole-resistant mechanism and the immunosuppression method used. In the neutropenic model, 100% survival was reached at an L-AmB dose of 16 mg/kg of body weight for the WT strain and the TR 34 /L98H isolate. In the steroid-treated group, 90.9% survival and 100% survival were achieved for the WT isolate and the TR 34 /L98H isolate with an L-AmB dose of 16 mg/kg, respectively. The 50% effective dose (ED 50 ) was 1.40 mg/kg (95% confidence interval [CI], 0.66 to 3.00 mg/kg) for the WT isolate and 1.92 mg/kg (95% CI, 0.60 to 6.17 mg/kg) for the TR 34 /L98H isolate in the neutropenic model and was 2.40 mg/kg (95% CI, 1.93 to 2.97 mg/kg) for the WT isolate and 2.56 mg/kg (95% CI, 1.43 to 4.56 mg/kg) for the TR 34 /L98H isolate in the steroid-treated group. Overall, there were no significant differences between the two different immunosuppressed conditions in the efficacy of L-AmB against the wild-type and azole-resistant isolates (P Ͼ 0.9). However, the required L-AmB exposure was significantly higher than that seen in the immunocompetent model.

Section: Figmentioning

confidence: 88%

In Vivo Efficacy of Liposomal Amphotericin B against Wild-Type and Azole-Resistant Aspergillus fumigatus Isolates in Two Different Immunosuppression Models of Invasive Aspergillosis

Seyedmousavi

Mouton

Melchers

et al. 2017

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“…However, this requires further investigation. Understanding the correlation between the genotype of the isolates and the clinical disease (45), which may vary from country to country, and therapeutic modalities, including the antifungal susceptibility patterns of causative agents against a panel of available systemic antifungal compounds (46), is a valuable asset for clinicians, clinical mycology/microbiology laboratories, and health care professionals and may guide personalized therapy.…”

Section: Discussionmentioning

confidence: 99%

Genetic Diversity and In Vitro Antifungal Susceptibility of 200 Clinical and Environmental Aspergillus flavus Isolates

Armaki

Hedayati

Ansari

et al. 2017

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Aspergillus flavus has been frequently reported as the leading cause of invasive aspergillosis in certain tropical and subtropical countries. Two hundred A. flavus strains originating from clinical and environmental sources and collected between 2008 and 2015 were phylogenetically identified at the species level by analyzing partial ␤-tubulin and calmodulin genes. In vitro antifungal susceptibility testing was performed against antifungals using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. In addition, genotyping was performed using a short-tandem-repeat (STR) assay of a panel of six microsatellite markers (A. flavus 2A, 2B, 2C, 3A, 3B, and 3C), in order to determine the genetic variation and the potential relationship between clinical and environmental isolates. The geometric means of the minimum inhibitory concentrations/minimum effective concentrations (MICs/MECs) of the antifungals across all isolates were (in increasing order): posaconazole, 0.13 mg/liter; anidulafungin, 0.16 mg/liter; itraconazole, 0.29 mg/liter; caspofungin, 0.42 mg/liter; voriconazole, 0.64 mg/liter; isavuconazole, 1.10 mg/liter; amphotericin B, 3.35 mg/liter; and flucytosine, 62.97 mg/liter. All of the clinical isolates were genetically different. However, an identical microsatellite genotype was found between a clinical isolate and two environmental strains. In conclusion, posaconazole and anidulafungin showed the greatest in vitro activity among systemic azoles and echinocandins, respectively. However, the majority of the A. flavus isolates showed reduced susceptibility to amphotericin B. Antifungal susceptibility of A. flavus was not linked with the clinical or environmental source of isolation. Microsatellite genotyping may suggest an association between clinical and environmental strains, although this requires further investigation.

“…In an athymic murine model of CBM caused by F. pedrosoi, terbinafine, especially at the highest dose, was able to reduce the inflammatory response to the infection to levels similar to those with azoles (33), although a total cure in patients with CBM remains difficult to achieve (26,34). On the other hand, various formulations of amphotericin B have been developed and are now available in most countries (35). The compound is nevertheless not recommended as a first-line therapy in chronic infections because of its adverse effects, such as nephrotoxicity, neurotoxicity, hematological side effects, and allergic reactions (36).…”

mentioning

confidence: 99%

“…The compound is nevertheless not recommended as a first-line therapy in chronic infections because of its adverse effects, such as nephrotoxicity, neurotoxicity, hematological side effects, and allergic reactions (36). However, the use of combination therapy can reduce cost-and toxicity-related effects and may prevent the emergence of resistance (35). Combination therapy is also recommended in salvage therapy scenarios for patients with antifungalresistant and invasive refractory mycoses (37).…”

mentioning

confidence: 99%

Combination of Amphotericin B and Terbinafine against Melanized Fungi Associated with Chromoblastomycosis

Deng¹,

Hoog

et al. 2018