Voriconazole (VRC) is Effective against Posaconazole (POSA)-Preexposed Aspergillus fumigatus (AF) in Experimental Aspergillosis in Flies.


Author address: 

MD Anderson Cancer Ctr., Houston, TX.


Background: Recent trials showed POSA as effective prophylaxis in patients with hematologic malignancy. As aspergillosis (IA) was the most frequent breakthrough mycosis in these studies, and VRC has emerged as preferred treatment for IA, it is be important to determine whether pre-exposure of Aspergillus to POSA results in lack of activity of subsequent VRC in IA. Such in vivo data are lacking. Methods: We used AF conidia with or without prior exposure to POSA (3 serial passages on plates with either YAG or YAG+0.025µg/ml POSA). We infected Tl flies (2-4 day (d) old female flies, 30 per group) by injection (Lionakis et al. JID 2005) and assessed survival 8 d post infection (three independent experiments). Following infection, flies were fed either regular food, or food containing 1mg/ml VRC. Results: VRC-fed flies infected with AF conidiae without pre-exposure to POSA had a 28% 8d survival compared to 0% of infected flies who were fed no VRC-containing food (P=.0015). Exposure of AF to POSA prior to infection did not affect the protective effect of sequential VRC, resulting in 23% 8d survival (P=NS). There were no differences in lethality in VRC untreated flies infected with either POSA pre-exposed or not AF conidiae. Conclusions: Prior exposure of AF to POSA does not have any effect on the efficacy of VRC in protecting Tl flies post infection. Prior exposure to POSA does not have any effect on AF virulence in Tl flies

abstract No: 


Full conference title: 

47th Interscience Conference on Antimicrobial agents and Chemotherapy
    • ICAAC 47th