Aspergillus Species and Antifungals Susceptibility in Clinical Setting in the North of Portugal: Cryptic Species and Emerging Azoles Resistance in A. fumigatus

Abstract

<i>Aspergillus</i> spp. are agents of a broad-spectrum of diseases among humans. Their growing resistance to azoles, the cornerstone in the management of human aspergillosis, is a worrisome problem around the world. Considering lack of data from Portugal on this topic, particularly from the northern region, a retrospective surveillance study was planned to assess frequency of cryptic <i>Aspergillus</i> species and azoles resistance. A total of 227 clinical isolates, mainly from the respiratory tract (92.1%), collected from three hospitals serving a population of about three million people, were studied for their epidemiology and antifungal susceptibility patterns determined by the E.DEF.9.3 protocol of EUCAST. Employing molecular methods, seven <i>Aspergillus</i> complexes were identified; <i>Aspergillus fumigatus sensu stricto</i> was the most frequent isolate (86.7%). A 7.5% prevalence of cryptic species was found; <i>A. welwitschiae</i> (<i>A. niger</i> complex-3.1%) and <i>A. lentulus</i> (<i>A. fumigatus complex</i>-2.2%) were the most frequent. Amongst cryptic species, it was found a percentage of resistance to voriconazole, posaconazole and isavuconazole of 47.1, 82.4, and 100%, respectively. Five <i>A. fumigatus sensu stricto</i> showed pan-azole resistance. Sequencing their <i>cyp51A</i> gene revealed the presence of one isolate with TR46/Y121F/T289A mutation and two isolates with TR34/L98H mutation. This study emphasizes the need to identify strains to the species level and to evaluate their antifungal susceptibility in all human originated <i>Aspergillus</i> spp. isolates, particularly those from invasive aspergillosis.