Susceptibility of fungi isolated from the respiratory tract of falcons to amphotericin B, itraconazole and voriconazole

Abstract

The minimum inhibitory concentrations (mics) of fungi isolated from the air sacs of falcons before (group 1), and during antifungal treatment with amphotericin B nebulisation and oral itraconazole or voriconazole (group 2), or with itraconazole alone (group 3) or voriconazole alone (group 4) were determined. Before treatment, 95 per cent of the isolates, including Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger and Aspergillus terreus, were susceptible to voriconazole at mics up to 0.38 microg/ml, and all the isolates were susceptible at mics up to 1 microg/ml. Before treatment, 21 per cent of the isolates, including A fumigatus (27.6 per cent), A flavus (16.6 per cent), A niger (100 per cent) and A terreus (23 per cent), were resistant (mic > or =1 microg/ml) to itraconazole; 51 per cent of the isolates, including A fumigatus (31 per cent), A flavus (78 per cent), A niger (14 per cent) and A terreus (77 per cent), had mics of over 1 microg/ml to amphotericin B, and after treatment their mics increased significantly. In contrast, there were no significant differences between the mics of voriconazole and itraconazole for the different Aspergillus species before and during treatment with these antifungal agents.

For Debate: May the Use of the Polyene Macrolide Natamycin as a Food Additive Foster Emergence of Polyene-Resistance in Candida Species?

“…In agreement with this study, another study revealed that in Spain and Austria environmental Amphothericin B resistant A. fumigatus strains could be isolated [8]. Hence, it is not surprising that almost all strains of A. fumigatus, A. flavus and A. terreus isolated from the air sac of falcons were Amphothericin B resistant [115,116]. As reviewed recently, resistance mechanisms were identical in environmental as well as clinical isolates, thus strongly suggesting that the mutation in the clinical isolate has been acquired from an environmental strain [98].…”

Aspergillusinfections in birds: a review

“…Literature regarding in vitro susceptibilities of antifungal agents for avian A. fumigatus strains in birds is scarce. The minimal inhibitory concentration of thiabendazole, 5-fluorocytosine, fluconazole, ketoconazole, caspofungin, amphotericin B, itraconazole and voriconazole for a limited number of A. fumigatus strains isolated from raptors has been determined using non-standardized methods (Redig & Duke, 1985;Silvanose et al, 2006Silvanose et al, , 2009. Currently, a reference method is available to test the antifungal susceptibility of filamentous fungi (Clinical and Laboratory Standards Institute document M38-A2), thus solving the lack of standardization.…”

Opportunistic infection of Aspergillus and bacteria in captive Cape vultures (Gyps coprotheres)

“…The emergence of avian A. fumigatus strains that are resistant to both itraconazole and voriconazole, the first line drugs against aspergillosis, is a challenge to be considered in the treatment of avian aspergillosis [18] . Further, in A. fumigatus infected birds, treatment by voriconazole have failed due to chronic fatigue syndrome usually induced by underlying Staphylococci infections [26] .…”