The Emergence of Rare Clinical Aspergillus Species in Qatar: Molecular Characterization and Antifungal Susceptibility Profiles

Abstract

Aspergillus are ubiquitous mold species that infect immunocompetent and immunocompromised patients. The symptoms are diverse and range from allergic reactions, bronchopulmonary infection, and bronchitis, to invasive aspergillosis. The aim of this study was to characterize 70 Aspergillus isolates recovered from clinical specimens of patients with various clinical conditions presented at Hamad general hospital in Doha, Qatar, by using molecular methods and to determine their in vitro antifungal susceptibility patterns using the Clinical and Laboratory Standards Institute (CLSI) M38-A2 reference method. Fourteen Aspergillus species were identified by sequencing β-tubulin and calmodulin genes, including 10 rare and cryptic species not commonly recovered from human clinical specimens. Aspergillus welwitschiae is reported in this study for the first time in patients with fungal rhinosinusitis ( n = 6) and one patient with a lower respiratory infection. Moreover, Aspergillus pseudonomius is reported in a patient with fungal rhinosinusitis which is considered as the first report ever from clinical specimens. In addition, Aspergillus sublatus is reported for the first time in a patient with cystic fibrosis. In general, our Aspergillus strains exhibited low MIC values for most of the antifungal drugs tested. One strain of Aspergillus fumigatus showed high MECs for echinocandins and low MICs for the rest of the drugs tested. Another strain of A. fumigatus exhibited high MIC for itraconazole and categorized as non-wild type. These findings require further analysis of their molecular basis of resistance. In conclusion, reliable identification of Aspergillus species is achieved by using molecular sequencing, especially for the emerging rare and cryptic species. They are mostly indistinguishable by conventional methods and might exhibit variable antifungal susceptibility profiles. Moreover, investigation of the antifungal susceptibility patterns is necessary for improved antifungal therapy against aspergillosis.

Aspergillus fumigatusand aspergillosis: From basics to clinics

“…2017 , Talbot & Barrs 2018 , Zoran et al. 2018 , Salah et al. 2019 , Mendoza et al.…”

Development of multiplex real-time PCR for rapid identification and quantitative analysis of Aspergillus species

“…The method of Aspergillus species identification includes morphologic identification of fungi through culture and molecular identification via the polymerase chain reaction (PCR) [5,6]. The former method is currently the gold standard; however, its use can depend largely on clinical specimen quality and the proficiency of the microbiology test personnel [6,7] The latter method, molecular identification of filamentous ascomycetes, is mainly conducted through sequence analysis of the internal transcribed spacer (ITS) region, and β-tubulin (benA) and calmodulin (CaM) genes are also used for cryptic species-level identification [2,8,9]. However sequencing-based identification is time-consuming, as it takes 5-17 days to reach the final diagnosis; specifically, it takes 3-14 days to produce conidia following fungal culture from the clinical sample, followed by an additional 2-3 days to extract DNA from the conidia and obtain sequencing analysis results [10,11].…”

“…Therefore, to take advantage and overcome the shortcomings of the multi-step molecular diagnosis method, there have been many efforts to explore new diagnostic approaches [6][7][8][9][10][11][12][13][14]. In this study, we aimed to develop a method for rapid molecular identification by using a multiplex platform that allows for quantitative analysis of major Aspergillus sections and rapid detection of azole resistance.…”

Aspergillus derived mycotoxins in food and the environment: Prevalence, detection, and toxicity

“…A. fumigatus is a widespread species responsible for human aspergillosis with a mortality rate of 40–90 % in immune-compromised patients. Approximately 90 % of human IA infections have been identified [ 288 ].Furthermore, A. flavus causes about 30 % of all aspergillosis cases in the United States [ 289 ], affecting around 11 million patients annually.…”