In recent years acquired azole resistance in Aspergillus fumigatus has been increasingly reported. A dominant mechanism of resistance (TR/L98H) was found in clinical and environmental isolates from the Netherlands and a link to the use of azoles in the environment was suggested. During the international surveillance of azole resistance in A. fumigatus (SCARE Network) intrinsic resistance was observed in 5 out of 209 clinical isolates collected in Italy and the TR/L98H was detected in all the 5 isolates. The aim of the present study was to investigate the prevalence of azole resistance in environmental A. fumigatus isolates collected in Italy. A total of 47 soil and compost samples were treated according to previously described methods (Snelders Appl.Environ.Microbiol 2009; 75:4053), plated on agar medium with and without itraconazole (4 mg/L) and incubated at 37° and 42°C for 72 hours. A. fumigatus isolates grown in presence of itraconazole were tested for antifungal susceptibility to itraconazole, posaconazole and voriconazole by EUCAST broth microdilution and E-test methods. Sequencing of b-tubulin and cyp51A genes was performed in resistant isolates. Elevated azole MICs were displayed by nine isolates from five different soil samples, namely apple orchard (1 isolate), compost (2), and cucurbit yields (6). The nine isolates were all confirmed to belong to A. fumigatus sensu stricto by b-tubulin sequencing. No cryptic species were detected. Seven out of the nine resistant isolates harboured the same TR/L98H mutation of cyp51A as well as a tandem repeat in the promoter region. These findings, together with the occurrence of resistant clinical isolates, suggest that the possibility of azole resistance should be taken in account in primary patient care.

Azole resistant Aspergillus fumigatus in the environment in Italy / A.M. Tortorano, V. Venier, A. Prigitano, M.C. Esposto, M. Cogliati. - In: MYCOSES. - ISSN 0933-7407. - 55:Suppl. 4(2012 Jun). (Intervento presentato al 18. convegno ISHAM 2012 tenutosi a Berlin nel 2012).

Azole resistant Aspergillus fumigatus in the environment in Italy

A.M. Tortorano;A. Prigitano;M.C. Esposto
Penultimo
;
M. Cogliati
2012

Abstract

In recent years acquired azole resistance in Aspergillus fumigatus has been increasingly reported. A dominant mechanism of resistance (TR/L98H) was found in clinical and environmental isolates from the Netherlands and a link to the use of azoles in the environment was suggested. During the international surveillance of azole resistance in A. fumigatus (SCARE Network) intrinsic resistance was observed in 5 out of 209 clinical isolates collected in Italy and the TR/L98H was detected in all the 5 isolates. The aim of the present study was to investigate the prevalence of azole resistance in environmental A. fumigatus isolates collected in Italy. A total of 47 soil and compost samples were treated according to previously described methods (Snelders Appl.Environ.Microbiol 2009; 75:4053), plated on agar medium with and without itraconazole (4 mg/L) and incubated at 37° and 42°C for 72 hours. A. fumigatus isolates grown in presence of itraconazole were tested for antifungal susceptibility to itraconazole, posaconazole and voriconazole by EUCAST broth microdilution and E-test methods. Sequencing of b-tubulin and cyp51A genes was performed in resistant isolates. Elevated azole MICs were displayed by nine isolates from five different soil samples, namely apple orchard (1 isolate), compost (2), and cucurbit yields (6). The nine isolates were all confirmed to belong to A. fumigatus sensu stricto by b-tubulin sequencing. No cryptic species were detected. Seven out of the nine resistant isolates harboured the same TR/L98H mutation of cyp51A as well as a tandem repeat in the promoter region. These findings, together with the occurrence of resistant clinical isolates, suggest that the possibility of azole resistance should be taken in account in primary patient care.
Settore MED/42 - Igiene Generale e Applicata
giu-2012
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/226932
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