In vitro amphotericin B resistance in clinical isolates of Aspergillus terreus, with a head-to-head comparison to voriconazole

Amphotericin B therapy continues to be the "gold standard'? in the treatmen t of invasive aspergillosis in the immunocompromised host. Although Aspergi llus fumigatus and Aspergillus flavus constitute the major species, several reports have described invasive pulmonary or disseminated disease due to t he less common Aspergillus terreus and dismal clinical outcomes with high-d ose amphotericin B. We therefore evaluated 101 clinical isolates of A. terr eus for their susceptibility to amphotericin B and the investigational tria zole voriconazole by using the National Committee for Clinical Laboratory S tandards M27-A method modified for mould testing. Forty-eight-hour MICs ind icated 98 and 0% resistance to amphotericin B and voriconazole, respectivel y. We conclude that A. terreus should be added to the list of etiologic age nts refractory to conventional amphotericin B therapy and suggest the poten tial clinical utility of voriconazole in aspergillosis due to this species.