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

Azole-resistant Aspergillus fumigatus is 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 Aspergillus isolates 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. fumigatus in 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. fumigatus specimens were isolated from 14 patients (12.8%). Of these 14 patients, only 2 had proven or probable IA (10.5%). Mutations at the cyp51A gene were observed in 23 of the 25 A. fumigatus isolates; 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 Aspergillus species by AsperGenius PCR. A. fumigatus was detected by AsperGenius in 20 patients, and 3 of these patients carried cyp51A mutations. Two patients had proven or probable IA and cyp51A mutation (11.7%). Our study has shown that the detection of azole-resistant A. fumigatus in 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.

Epidemiology and reporting of candidaemia in Belgium: a multi-centre study.

The primary aim of this study was to collect national epidemiological data on candidaemia and to determine the reporting time of species identification and antifungal susceptibility in clinical practice. During a 1-year period (March 2013 until February 2014), every first Candida isolate from each episode of candidaemia was included prospectively from 30 Belgian hospitals. Identification and susceptibility testing were performed according to local procedures and isolates were sent to the National Reference Center for Mycosis. Species identification was checked by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and internal transcribed spacer (ITS) sequencing in case no reliable identification was obtained by MALDI-TOF MS. Antifungal susceptibility testing was performed according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) methodology. A total of 355 isolates were retrieved from 338 patients. The mean incidence rate of candidaemia was 0.44 (range: 0.07 to 1.43) per 1000 admissions or 0.65 (range: 0.11 to 2.00) per 10,000 patient days. Candida albicans was most frequently found (50.4 %), followed by C. glabrata (27.3 %) and C. parapsilosis sensu lato (9.8 %). The overall resistance to fluconazole was 7.6 %, ranging from 3.9 % in C. albicans to 20.0 % in C. tropicalis. Only one C. glabrata isolate was resistant to the echinocandins. Four days after blood culture positivity, 99.7 % of the identifications and 90.3 % of the antifungal profiles were reported to the treating clinician. Candidaemia incidence rates differed up to 20-fold among Belgian hospitals; no clear factors explaining this difference were identified. The overall antifungal resistance rates were low but high azole resistance rates were recorded in C. tropicalis.