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Caspofungin Resistance in Clinical Aspergillus Flavus Isolates Publisher Pubmed



Yassin Z1 ; Lotfali E2 ; Khourgami MR3 ; Omidi N4 ; Fattahi A5 ; Nasrollahi SA5 ; Ghasemi R6
Authors
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Authors Affiliations
  1. 1. Antimicrobial Resistance Research Center, Iran University of Medical Sciences, Tehran, Iran
  2. 2. Department of Medical Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
  3. 3. Rajaie Cardiovascular, Medical, and Research Center, Rajaie Hospital, Iran University of Medical Sciences, Tehran, Iran
  4. 4. Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
  5. 5. Center for Research and Training in Skin Diseases and Leprosy, Tehran University of Medical Sciences, Tehran, Iran
  6. 6. Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Source: Journal of Medical Mycology Published:2021


Abstract

Introduction and Aims: The present study was conducted to determine the candidate genes involved in caspofungin (CAS) resistance in clinical isolates of Aspergillus flavus (A. flavus). Materials and Methods: The antifungal susceptibility assay of the CAS was performed on 14 clinical isolates of A. flavus using the CLSI-M-38-A2 broth micro-dilution protocol. Since CAS had various potencies, the minimum effective concentration (MEC) of anidulafungin (AND) was also evaluated in the present study. The FKS1 gene sequencing was conducted to assess whether mutations occurred in the whole FKS1 gene as well as hot spot regions of the FKS1 gene of the two resistant isolates. A complementary DNA-amplified fragment length polymorphism (CDNA-AFLP) method was performed to investigate differential gene expression between the two resistant and two sensitive clinical isolates in the presence of CAS. Furthermore, quantitative real-time PCR (QRT-PCR) was utilized to determine the relative expression levels of the identified genes. Results: No mutations were observed in the whole FKS1 gene hot spot regions of the FKS1 genes in the resistant isolates. A subset of two genes with known biological functions and four genes with unknown biological functions were identified in the CAS-resistant isolates using the CDNA-AFLP. The QRT-PCR revealed the down-regulation of the P-type ATPase and ubiquinone biosynthesis methyltransferase COQ5 in the CAS-resistant isolates, compared to the susceptible isolates. Conclusion: The findings showed that P-type ATPase and ubiquinone biosynthesis methyltransferase COQ5 might be involved in the CAS-resistance A. flavus clinical isolates. Moreover, a subset of genes was differentially expressed to enhance fungi survival in CAS exposure. Further studies are recommended to highlight the gene overexpression and knock-out experiments in A. flavus or surrogate organisms to confirm that these mentioned genes confer the CAS resistant A. flavus. © 2021 SFMM