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

PLoS One. 2020 Mar 9;15(3):e0229561. doi: 10.1371/journal.pone.0229561. eCollection 2020.

Abstract

The identification of Aspergillus species and azole resistance is highly important for the treatment of invasive aspergillosis (IA), which requires improvements in current fungal diagnostic methods. We aimed to develop multiplex real-time PCR to identify major Aspergillus section and azole resistance. BenA and cyp51A genes were used to design primers, probes, and control DNA for multiplex PCR. Qualitative and quantitative analysis was conducted for 71 Aspergillus and 47 non-Aspergillus isolates. Further, the limit of detection (LOD) and limit of quantitation (LOQ) from hyphae or conidia were determined according to the culture time. Newly developed real-time PCR showed 100% specificity to each Aspergillus section (Fumigati, Nigri, Flavi, and Terrei), without cross-reaction between different sections. In quantitative analysis of sensitivity measurements, LOD and LOQ were 40 fg and 400 fg, respectively. Melting temperature analysis of the cyp51A promoter to identify azole resistance showed temperatures of 83.0 ± 0.3°C and 85.6 ± 0.6°C for susceptible A. fumigatus and resistant isolates with TR34 mutation, respectively. The minimum culture time and fungal colony size required for successful detection were 24 h and 0.4 cm in diameter, respectively. The developed multiplex real-time PCR can identify common Aspergillus sections quantitatively and detect presence of the TR34 mutation. Further, this method shows high sensitivity and specificity, allowing successful detection of early-stage fungal colonies within a day of incubation. These results can provide a template for rapid and accurate diagnosis of IA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antifungal Agents / pharmacology
  • Aspergillosis / microbiology
  • Aspergillus / classification
  • Aspergillus / genetics*
  • Azoles / pharmacology
  • Cytochrome P-450 Enzyme System / genetics
  • DNA Primers
  • Drug Resistance, Fungal / genetics*
  • Fungal Proteins / genetics
  • Invasive Fungal Infections / drug therapy
  • Invasive Fungal Infections / genetics
  • Microbial Sensitivity Tests
  • Multiplex Polymerase Chain Reaction / methods*
  • Real-Time Polymerase Chain Reaction / methods
  • Species Specificity

Substances

  • Antifungal Agents
  • Azoles
  • DNA Primers
  • Fungal Proteins
  • Cytochrome P-450 Enzyme System
  • cytochrome P-450 CYP51A, Aspergillus

Grants and funding

This research was supported by an industry-university research grant (5-2019-D0166-00004) through the Yuhan Corporation. The funder provided support in the form of salaries for authors [WBK, CP and HSC], but did not have any additional role in the study design, data collection, and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘Author contributions’ section.