<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>This study aimed to investigate azole resistance mechanisms in <italic>Aspergillus flavus,</italic> which involve <italic>cyp</italic>51A and <italic>cyp</italic>51B genes. Real-time Reverse Transcriptase qPCR method was applied to determine the overexpression of <italic>cyp</italic>51A and <italic>cyp</italic>51B genes for 34 <italic>A. flavus</italic> isolates. PCR sequencing of these two genes was used to detect the presence of gene mutations. Susceptibility test found sensitivity to voriconazole (VOR) in all strains. 14.7% and 8.8% of isolates were resistant to itraconazole (IT) and posaconazole (POS), respectively, with a cross-resistance in 5.8%. For the double resistant isolates (IT/POS), the expression of <italic>cyp</italic>51A was up to 17-fold higher. PCR sequencing showed the presence of 2 mutations in <italic>cyp</italic>51A: a synonymous point mutation (P61P) in eight isolates, which did not affect the structure of CYP51A protein, and another non synonymous mutation (G206L) for only the TN-33 strain (cross IT/POS resistance) causing an amino acid change in the protein sequence. However, we noted in <italic>cyp</italic>51B the presence of the only non-synonymous mutation (L177G) causing a change in amino acids in the protein sequence for the TN-31 strain, which exhibits IT/POS cross-resistance. A short single intron of 67 bp was identified in the <italic>cyp</italic>51A gene, whereas three short introns of 54, 53, and 160 bp were identified in the <italic>cyp</italic>51B gene. According to the models provided by PatchDock software, the presence of non-synonymous mutations did not affect the interaction of CYP51A and CYP51B proteins with antifungals. In our study, the overexpression of the <italic>cyp</italic>51A and <italic>cyp</italic>51B genes is the primary mechanism responsible for resistance in <italic>A. flavus</italic> collection. Nevertheless, other resistance mechanisms can be involved.</p>
</abstract>

This study aimed to investigate azole resistance mechanisms in Aspergillus flavus, which involve cyp51A and cyp51B genes. Real-time Reverse Transcriptase qPCR method was applied to determine the overexpression of cyp51A and cyp51B genes for 34 A. flavus isolates. PCR sequencing of these two genes was used to detect the presence of gene mutations. Susceptibility test found sensitivity to voriconazole (VOR) in all strains. 14.7% and 8.8% of isolates were resistant to itraconazole (IT) and posaconazole (POS), respectively, with a cross-resistance in 5.8%. For the double resistant isolates (IT/POS), the expression of cyp51A was up to 17-fold higher. PCR sequencing showed the presence of 2 mutations in cyp51A: a synonymous point mutation (P61P) in eight isolates, which did not affect the structure of CYP51A protein, and another non synonymous mutation (G206L) for only the TN-33 strain (cross IT/POS resistance) causing an amino acid change in the protein sequence. However, we noted in cyp51B the presence of the only non-synonymous mutation (L177G) causing a change in amino acids in the protein sequence for the TN-31 strain, which exhibits IT/POS cross-resistance. A short single intron of 67 bp was identified in the cyp51A gene, whereas three short introns of 54, 53, and 160 bp were identified in the cyp51B gene. According to the models provided by PatchDock software, the presence of non-synonymous mutations did not affect the interaction of CYP51A and CYP51B proteins with antifungals. In our study, the overexpression of the cyp51A and cyp51B genes is the primary mechanism responsible for resistance in A. flavus collection. Nevertheless, other resistance mechanisms can be involved.

Investigation of Azole Resistance Involving <italic>cyp</italic>51A and <italic>cyp</italic>51B Genes in Clinical <italic>Aspergillus flavus</italic> Isolates

Polish Journal of Microbiology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Investigation of Azole Resistance Involving 51A and 51B Genes in Clinical  Isolates

This study aimed to investigate azole resistance mechanisms in Aspergillus flavus, which involve cyp51A and cyp51B genes. Real-time Reverse Transcriptase qPCR...

Investigation of Azole Resistance Involving cyp51A and cyp51B Genes in Clinical Aspergillus flavus Isolates

Article Category: Original Paper

Published Online: May 03, 2024

Page range: 131 - 142

Received: Aug 03, 2023

Accepted: Dec 03, 2023

DOI: https://doi.org/10.33073/pjm-2024-001

Keywords
antifungal susceptibility, mechanisms of resistance, azole resistance, DNA mutation, 51A, 51B

© 2024 Dhoha Ghorbel et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Investigation of Azole Resistance Involving cyp51A and cyp51B Genes in Clinical Aspergillus flavus Isolates

Article Category: Original Paper

Published Online: May 03, 2024

Page range: 131 - 142

Received: Aug 03, 2023

Accepted: Dec 03, 2023

DOI: https://doi.org/10.33073/pjm-2024-001

Keywordsantifungal susceptibility, mechanisms of resistance, azole resistance, DNA mutation, 51A, 51B

© 2024 Dhoha Ghorbel et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
antifungal susceptibility, mechanisms of resistance, azole resistance, DNA mutation, 51A, 51B