Quantitative PCR Detection Of Circulating Dna In Serum For Early Diagnosis Of Mucormycosis

Ref ID: 18761

Author:

L. Millon, ScD (Doctor of Science) – Professor1,2, F. Grenouillet, ScD – Hospital Practionner 1,2, F. Larosa, MD – Hospital Practionner 1, A. P. Bellanger, PhD – Associate Professor 1,2, F. Skana, BSc – technician 1, S. Rocchi, MSc – ScD student 1,2,

Author address:

1Univ. Hosp., Besancon, France, 2UMR CNRS 6249, Besançon, France, 3Univ. Hosp., Besancon, France.

Full conference title:

52nd Annual ICAAC

Date: 9 September 2014

Abstract:

Background: Early specific diagnosis and prompt therapeutic intervention with active antifungal treatment such as amphotericin B is essential for improving the outcome of mucormycosis. Our aim was to assess detection of circulating DNA of the most common species of mucorales for early diagnosis of mucormycosis in patients at risk. Methods: We retrospectively evaluated a combination of 3 qPCR assays targeting Mucor/Rhizopus, Lichtheimia, and Rhizomucor using serial serum samples from 10 patients diagnosed with proven mucormycosis between 2006 and 2012 in our hospital. Serum sampled between D-68 and D10 from the time of diagnosis were tested. Automatic DNA extraction was performed using a Large Volume MagNa Pure Isolation Kit (Roche Diagnostics). qPCR was performed on a Light Cycler 480 (Roche Diagnostics) using the primers and hydrolysis probes targeting Mucor sp/Rhizopus sp, Lichtheimia sp, and Rhizomucor sp described by Haugland et al (http://www.epa.gov/microbes/moldtech.htm). Results: DNA from Mucorales was detected in the serum of 9/10 patients before mucormycosis diagnosis was confirmed by histopathological examination and/or positive culture. Positive PCR was observed on serum sampled from 68 to 3 days before diagnosis, with quantification cycle between 39 and 25 cycles. All the qPCR results were concordant with culture and/or PCR-based identification of the causing agents in tissue (Lichtheimia sp, Rhizomucor sp, Mucor sp/Rhizopus sp in 4, 3, and 2 patients respectively). qPCR was negative in only one patient with proven cutaneous mucormycosis caused by Lichteimia sp. Conclusion: Our study suggests that using specific qPCR targeting several species of mucorales according to local ecology for screening patients at risk could be useful in a clinical setting. Cost/efficacy of this strategy should be evaluated. However, given the human and economic cost of mucormycosis, the importance of rapid diagnosis to initiate a prompt, specific antifungal therapy, and the low cost of a high-throughput qPCR system, this strategy could be highly attractive.

Abstract Number: M-1692

Conference Poster: y

Conference Year: 2012

Link to conference website: NULL

New link: NULL

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