Monitoring of invasive aspergillos is antifungal therapy by quantitative reverse transcriptase real-time polymerase chain reaction (qRT- PCR)

Hossein Khodadadi*1, Ladan Karimi 2, Hadis Jafarian 1, Keyvan Pakshir 1, Kamiar Zomorodian 1.

Author address: 

1 Shiraz University of Medical Sciences; Medical Parasitology and Mycology; 2 Social Security Organization; Shahid Beheshti Hospital; Microbiology.

Abstract: 

Background: Assessment of antifungal therapeutic efficacy of invasive aspergillosis (IA) is essential
and reliable methods to quantify response to anti-Aspergillus drugs are desirable. Although serum
beta-glucan (BG) and galactomannan (GM) levels were evaluated during antifungal therapy, the levels
of these antigens fluctuate irregularly and do not show early therapeutic response correctly. Recently
some efforts focused on detection and quantification of Aspergillus RNA in serum as a biomarker. We
developed a quantitative reverse transcriptase real-time polymerase chain reaction (qRT-PCR) for
following up responses to antifungals in IA patients.
Material/methods: Total RNA was extracted from 188 blood samples of 36 patients with proven or
probable IA during their antifungal therapy regimen. The loads of Aspergillus 18S rRNA were
quantified by a newly designed pan-Aspergillus qRT-PCR. GM levels in serum were measured
simultaneously and clinical outcome were assessed. The correlation between the changes of
circulating Aspergillus RNA load and serum GM levels and the clinical outcome were statistically
compared.
Results: Thirty-six patients with newly diagnosed IA and receiving anti-Aspergillus drugs were
evaluated weekly for 10 weeks. 34 out of 188 (18.1%) blood samples belonging to 9 patients had
positive qRT-PCR results. Aspergillus RNA load decreasing was seen in 7 patients. Fungal RNA
decrease began from third week of antifungal therapy initiation. This decrease associated with an
excellent response to antifungals. Although changes of blood Aspergillus RNA load correlates with
clinical outcome, the fungal RNA load did not show correlation with GM levels.
Conclusions: Changes of blood Aspergillus RNA load during antifungal therapy correlates with final
clinical outcome. The measurement of changes of circulating Aspergillus RNA load in combination with
other assays may help for monitoring the response to anti-fungal therapy.

2017

abstract No: 

P0982

Full conference title: 

27th European Congress of Clinical Microbiology and Infectious Diseases (2017, Vienna)
    • ECCMID 27th (2017)