Trends on Aspergillus Epidemiology—Perspectives from a National Reference Laboratory Surveillance Program

Abstract

Identification of Aspergillus to species level is important since sibling species may display variable susceptibilities to multiple antifungal drugs and also because correct identification contributes to improve the knowledge of epidemiological studies. Two retrospective laboratory studies were conducted on Aspergillus surveillance at the Portuguese National Mycology Reference Laboratory. The first, covering the period 2017–2018, aimed to study the molecular epidemiology of 256 Aspergillus isolates obtained from patients with respiratory, subcutaneous, or systemic infections and from environmental samples. The second, using our entire collection of clinical and environmental A. fumigatus isolates (N = 337), collected between 2012 and 2019, aimed to determine the frequency of azole-resistant A. fumigatus isolates. Aspergillus fumigatus sensu stricto was the most frequent species in both clinical and environmental samples. Overall, and considering all Aspergillus sections identified, a high frequency of cryptic species was detected, based on beta-tubulin or calmodulin sequencing (37% in clinical and 51% in environmental isolates). Regarding all Fumigati isolates recovered from 2012–2019, the frequency of cryptic species was 5.3% (18/337), with the identification of A. felis (complex), A. lentulus, A. udagawae, A. hiratsukae, and A. oerlinghauensis. To determine the frequency of azole resistance of A. fumigatus, isolates were screened for azole resistance using azole-agars, and 53 possible resistant isolates were tested by the CLSI microdilution reference method. Nine A. fumigatus sensu stricto and six Fumigati cryptic isolates showed high minimal inhibitory concentrations to itraconazole, voriconazole, and/or posaconazole. Real-time PCR to detect cyp51A mutations and sequencing of cyp51A gene and its promoter were performed. The overall frequency of resistance to azoles in A. fumigatus sensu stricto was 3.0%. With this retrospective analysis, we were able to detect one azole-resistant G54R mutant A. fumigatus environmental isolate, collected in 2015. The TR34/L98H mutation, linked to environmental transmission route of azole resistance, was the most frequently detected mutation (N = 4; 1.4%). Our findings underline the demand for correct identification and susceptibility testing of Aspergillus isolates.

Azole resistance in Aspergillus fumigatus. The first 2‐year's Data from the Danish National Surveillance Study, 2018–2020

“…Three single point amino acid alterations (G54A, G54R and G432S) have been associated with azole resistance in both azole‐treated patients and the environment 27–30 . Five patients in this surveillance programme harboured isolates with a G54R and one patient an isolate with a G432S alteration.…”

“…4 Three single point amino acid alterations (G54A, G54R and G432S) have been associated with azole resistance in both azoletreated patients and the environment. [27][28][29][30] Five patients in this surveillance programme harboured isolates with a G54R and one patient an isolate with a G432S alteration. Unfortunately, we did not have access to clinical information or prior medication data to enable a discussion of the origin of these resistance mechanisms.…”

Synergy Between Pseudomonas aeruginosa Filtrates And Voriconazole Against Aspergillus fumigatus Biofilm Is Less for Mucoid Isolates From Persons With Cystic Fibrosis

“…001-03Yr.16). Assays were performed using the A. fumigatus virulent patient isolate 10AF [ATCC 90240 ( Denning et al., 1990 ; Denning and Stevens, 1991 )], or a VCZ-resistant isolate (AF21-23) with the most common mutation, TR34/L98H, in the promotor and within the cyp51A gene, which encodes the 14-demethylase enzyme critical to ergosterol synthesis ( Sabino et al., 2021 ). Sixteen P. aeruginosa isolates from CF patients (7 with mucoid phenotype and 9 with non-mucoid phenotype) and eight isolates of P. aeruginosa recovered from non-CF patients were randomly chosen from a library of patient cultures, and obtained after written informed consent, for biobanking of the specimens and subsequent use of the patients, approved by the Stanford University (SU) Institutional Review Board.…”

COVID-19-Associated Invasive Pulmonary Aspergillosis in the Intensive Care Unit: A Case Series in a Portuguese Hospital

“…Molecular identification of Aspergillus isolates was performed as described previously [ 16 ]. Antifungal susceptibility profiles were determined by broth microdilution reference method for susceptibility testing of molds.…”

“…Antifungal susceptibility profiles were determined by broth microdilution reference method for susceptibility testing of molds. The M38-A2 protocol from the Clinical and Laboratory Standards Institute was applied for determining the Minimal Inhibitory Concentrations (MIC) for itraconazole, voriconazole and posaconazole, as previously performed [ 16 ].…”