J Mycol Infect.  2024 Sep;29(3):137-154. 10.17966/JMI.2024.29.3.137.

Aspergillus aureoterreus, A. pseudonomiae, A. siamensis, and A. flocculosus-ochraceopetaliformis as Four New Pathogens of Eye Infection in DNA Barcoding Markers

• Kuwatjanakul W
• Khoi TT
• Wonglakorn L
• Samerpitak K

• KMID: 2563176
• DOI: http://doi.org/10.17966/JMI.2024.29.3.137

Abstract

Background
The use of a morphological method to determine Aspergillus species in routine laboratory investigation has always been challenged with low sensitivity and low specificity. Time-consuming specimen preparation and insufficient expertise are the crucial reasons. DNA barcoding markers have been introduced for identification as another gold standard method.
Objective
To investigate DNA barcoding markers in identifying Aspergillus strains isolated from patients with eye infection.
Methods
This study extracted 12 DNA samples of 12 Aspergillus strains. DNA barcoding genes, i.e., ITS, betatubulin (BT2), calmodulin (CAL), and actin (ACT) genes, were amplified and sequenced by polymerase chain reaction and Sanger's sequencing methods. All gene sequences were compared to those of the type or reference species collected from public databases. The species were identified with phylogenetic analyses in free applications from public websites.
Results
ITS, BT2 and CAL, and ACT identified 5, 6, and 3 species and 3, 2, and 1 species complex of Aspergillus, respectively. DNA barcoding with multi-locus sequence typing revealed four new pathogens of human eye infection, including A. aureoterreus, A. pseudonomiae, A. siamensis, and A. flocculosus-ochraceopetaliformis.
Conclusion
The DNA barcoding markers identified Aspergillus species with better specificity than the conventional method. The markers and techniques need to be used as tools for routine Aspergillus identification.

Keyword

Aspergillus infection; DNA barcoding; Fungal keratitis; New fungal pathogen