Culture-Based Methods and Molecular Tools for Azole-Resistant Aspergillus fumigatusDetection in a Belgian University Hospital

ABSTRACTAzole-resistant Aspergillus fumigatusis an increasing worldwide problem with major clinical implications. Surveillance is warranted to guide clinicians to provide optimal treatment to patients. To investigate azole resistance in clinical Aspergillusisolates in our institution, a Belgian university hospital, we conducted a laboratory-based surveillance between June 2015 and October 2016. Two different approaches were used: a prospective culture-based surveillance using VIPcheck on unselected A. fumigatus(n= 109 patients, including 19 patients with proven or probable invasive aspergillosis [IA]), followed by molecular detection of mutations conferring azole resistance, and a retrospective detection of azole-resistant A. fumigatusin bronchoalveolar lavage fluid using the commercially available AsperGenius PCR (n= 100 patients, including 29 patients with proven or probable IA). By VIPcheck, 25 azole-resistant A. fumigatusspecimens were isolated from 14 patients (12.8%). Of these 14 patients, only 2 had proven or probable IA (10.5%). Mutations at the cyp51Agene were observed in 23 of the 25 A. fumigatusisolates; TR34/L98H was the most prevalent mutation (46.7%), followed by TR46/Y121F/T289A (26.7%). Twenty-seven (27%) patients were positive for the presence of Aspergillusspecies by AsperGenius PCR. A. fumigatuswas detected by AsperGenius in 20 patients, and 3 of these patients carried cyp51Amutations. Two patients had proven or probable IA and cyp51Amutation (11.7%). Our study has shown that the detection of azole-resistant A. fumigatusin clinical isolates was a frequent finding in our institution. Hence, a rapid method for resistance detection may be useful to improve patient management. Centers that care for immunocompromised patients should perform routine surveillance to determine their local epidemiology.