Related Experiment Video
Updated: Sep 13, 2025
Isolation and Selection of Entomopathogenic Fungi from Soil Samples and Evaluation of Fungal Virulence against Insect Pests
Published on: September 28, 2021
Comparison of Morphological, Virulence, and Antifungal Susceptibility Characteristics Within Aspergillus Lentulus
Xiaodong Wang1, Cuirong Gao2, Aikedai Yusufu1
1Department of Dermatology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People's Republic of China.
Background:
The emerging pathogenic species Aspergillus lentulus, within the Aspergillus fumigatus complex, poses a significant threat to patient health owing to its high rates of drug resistance and mortality. The aim of this study was to characterize the intraspecies morphology, virulence, and in vitro antifungal susceptibility of A. lentulus.
Methods:
We cultured A. lentulus isolates from different sources (three clinical isolates and one environmental isolate), along with A. fumigatus (n=1) and Aspergillus fumigatiaffinis (n=1), to observe colony color, diameter, sporulation timing, and spore production. Virulence was assessed using a Galleria mellonella infection model, and survival curves were generated to evaluate strain pathogenicity. Antifungal susceptibility was determined using the colorimetric microdilution method with Sensititre YeastOne® panels.
Results:
Compared to A. fumigatus and A. fumigatiaffinis, A. lentulus exhibited whitish colonies with pale green overtones, delayed sporulation initiation, and reduced spore yield. The four A. lentulus isolates showed intrastrain variability in the timing of colony color transition, growth rates, sporulation onset, and spore quantification. Virulence experiments demonstrated that all A. lentulus isolates successfully infected G. mellonella larvae and exhibited concentration- and time-dependent survival patterns. Clinical isolates consistently showed significantly lower larval survival rates than the environmental isolates at all infection concentrations. Antifungal susceptibility testing revealed the following minimum inhibitory concentration (MIC) ranges for A. lentulus: posaconazole 0.5-2 μg/mL, itraconazole 1-2 μg/mL, and voriconazole 2-8 μg/mL. Specifically, the clinical isolate A. lentulus-10199 and environmental isolate A. lentulus-10201 exhibited elevated voriconazole MICs (8 μg/mL). All strains demonstrated high MICs for amphotericin B (≥4 μg/mL) and caspofungin (≥8 μg/mL).
Conclusion:
Aspergillus lentulus exhibited both interstrain and intrastrain variations in growth rate and sporulation characteristics. Clinical isolates demonstrated greater virulence potential than environmental isolates. Aspergillus lentulus displayed favorable susceptibility to posaconazole but reduced susceptibility to voriconazole, amphotericin B, and caspofungin.
Insights
Emerging Aspergillus lentulus shows varied growth and virulence, with clinical strains being more potent. This fungus is susceptible to posaconazole but resistant to voriconazole, amphotericin B, and caspofungin.
Area of Science:
- Medical Mycology
- Infectious Diseases
Background:
- Aspergillus lentulus, part of the Aspergillus fumigatus complex, is an emerging pathogen.
- It presents a significant health risk due to high drug resistance and mortality rates.
Purpose of the Study:
- To characterize the intraspecies morphology of Aspergillus lentulus.
- To assess the virulence of Aspergillus lentulus.
- To determine the in vitro antifungal susceptibility of Aspergillus lentulus.
Main Methods:
- Cultured Aspergillus lentulus, Aspergillus fumigatus, and Aspergillus fumigatiaffinis isolates.
- Assessed virulence using a Galleria mellonella infection model.
- Determined antifungal susceptibility via colorimetric microdilution with Sensititre YeastOne® panels.
Main Results:
- Aspergillus lentulus displayed distinct morphology, delayed sporulation, and reduced spore yield compared to other species.
- Intraspecies variability was observed in growth and sporulation characteristics.
- Clinical Aspergillus lentulus isolates showed higher virulence than environmental isolates in the Galleria mellonella model.
- Antifungal susceptibility testing revealed favorable susceptibility to posaconazole but reduced susceptibility to voriconazole, amphotericin B, and caspofungin, with some isolates showing elevated voriconazole MICs.
Conclusions:
- Aspergillus lentulus exhibits significant inter- and intrastrain variations in morphology and sporulation.
- Clinical isolates of Aspergillus lentulus possess greater virulence potential.
- Posaconazole demonstrates favorable activity against Aspergillus lentulus, while voriconazole, amphotericin B, and caspofungin show reduced susceptibility.
