Species distribution and antifungal susceptibility of clinical Aspergillus isolates: A multicentre study in Taiwan, 2016–2020

Epidemiological knowledge is important to guide antifungal therapy.


| INTRODUC TI ON
Members of the genus Aspergillus are ubiquitous saprophytic moulds that produce airborne conidia. They are implicated in diverse opportunistic fungal infections in humans, including keratitis; otomycosis; skin and soft tissue infections; and respiratory tract infections, including sinusitis, allergic bronchopulmonary aspergillosis, chronic pulmonary aspergillosis and invasive pulmonary aspergillosis (IPA). 1 The genus Aspergillus contains various species belonging to different sections, with Aspergillus fumigatus, A. flavus, A. terreus and section Nigri species being the most frequent in clinical samples. 1 Over the past decades, DNA sequencing-based identification has led to describing novel and morphologically similar cryptic species in different Aspergillus sections. 1 Given the species-specific characteristics in terms of the sites of infection and antifungal susceptibility, correct species identification is clinically relevant because it can aid in managing Aspergillus diseases, particularly invasive aspergillosis (IA). 2,3 Azoles and amphotericin B (AMB) are the mainstay therapies for aspergillosis treatment, and echinocandins are alternative or salvage therapy. 3 Nevertheless, some Aspergillus species have inherently reduced susceptibility to one or more antifungal classes and acquired azole resistance in A. fumigatus mostly due to mutations in the cyp51A gene has emerged, both compromising the therapeutic efficacy of antifungals. 3,4 Therefore, the 2017 ESCMID-ECMM-ERS Aspergillus guideline recommended identifying the Aspergillus isolates to the species complex level and performing antifungal susceptibility testing (AFST) for both clinical guidance in individual patients with aspergillosis and for epidemiological resistance surveillance along with cyp51A analysis in azole-resistant A. fumigatus (ARAF) isolates to monitor the trend of cyp51A mutation profiles. 3 Sequence-based identification and reference susceptibility testing are not routinely performed for clinically relevant Aspergillus isolates in most clinical laboratories in Asian countries, including Taiwan. 5 Given the lack of data, a national surveillance programme to elucidate the local epidemiology is necessary. The Taiwan

| MATERIAL S AND ME THODS
Twenty-five hospitals, comprising 11 medical centres and 14 regional hospitals in Taiwan, participated in the TSARM program ( Figure S1).
Briefly, during July-September 2016, 2018 and 2020, Aspergillus isolates from all types of clinical samples collected for routine diagnostic fungal culture test were obtained from the participating hospitals and sent to the TMRC for further analyses.
Aspergillus species were identified based on the macroscopic and microscopic characteristics and calmodulin gene sequencing. All isolates were grown on Sabouraud dextrose agar for 2-3 days at 35°C.
AMB was active against most Aspergillus isolates except for A. In conclusion, this study depicts the molecular epidemiology and species characteristics of Aspergillus in Taiwan, which aids in selecting appropriate antifungal therapy and underlines the need of speciation and susceptibility testing of disease-causing Aspergillus.

ACK N O WLE D G E M ENTS
We gratefully thank the following hospitals for participating the TSARM program (TSARM hospitals) and sharing the clinical

CO N FLI C T O F I NTER E S T S TATEM ENT
None to declare.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.