Screening for M220 mutation in azole-resistant Aspergillus fumigatus isolates from clinical and environmental specimens in Cuba

Abstract

Aspergillosis is a fungal disease caused by different Aspergillus species and have high morbidity/mortality rates. Aspergillus fumigatus is the main aetiological agent related to most of Aspergillus infections. The use of triazoles is recommended as first line of treatment, however, the reports of azole-resistant A. fumigatus due to mutations in CYP51 have increased around the world. The goals were to determine the antifungal susceptibility patterns for triazoles in thirty A. fumigatus isolates from clinical and environmental samples and to detect mutation M220 in the resistant ones. Determination of minimum inhibitory concentrations of every isolate was performed by using the Etest commercial method for itraconazole, voriconazole and posaconazole. For the resistant isolates, a PCR was performed for amplifying a 173 bp fragment of cyp51A and the resulting amplicons were sequenced. Nine out of 30 isolates were resistant to itraconazole and none were resistant to voriconazole or posaconazole. The alignment of sequences with a CYP51 A. fumigatus wild type strain did not show any modifications at codon 220. Other molecular mechanisms of resistance are probably related to the resistant phenotypes isolated.