Detection of circulating DNA for the diagnosis of invasive fusariosis: retrospective analysis of 15 proven cases

Abstract

Fusarium spp. are plant pathogens and opportunistic pathogens in severely immunocompromised (hematological malignancy, neutropenia, solid organ transplantation, …) and severely burned patients. Invasive fusariosis often disseminates and mortality remains high partly due to delayed diagnosis in the absence of a positive culture. The aim of our study is to design a qPCR assay and evaluate the detection of Fusarium spp. DNA for early diagnosis of invasive infection. A qPCR assay was designed and optimized to identify all Fusarium species complex and secondarily evaluated on patient samples. A total of 81 blood samples from 15 patients diagnosed with proven invasive fusariosis from 9 centers in France were retrospectively tested. Circulating DNA was detected in 14 patients out of 15 (sensitivity of 93% [IC95, 70.1-99.7]). Detection was possible up to 18 days (median 6 days) before the diagnosis was confirmed by positive blood culture or biopsy. By comparison serum galactomannan and ß-D-glucan were positive in 7.1 and 58.3% of patients respectively. qPCR was negative for all patients with other invasive fungal diseases (IFD) tested (n = 12) and IFD-free control patients (n = 40). No cross-reactions were detected using DNA extracted from 81 other opportunistic fungi. We developed and validated a pan-Fusarium qPCR assay in serum/plasma with high sensitivity, specificity and reproducibility that could facilitates early diagnosis and treatment monitoring of invasive fusariosis.

Performance of the beta-glucan test for the diagnosis of invasive fusariosis and scedosporiosis: a meta-analysis

“…Of these, 30 were single case reports and 9 were cohort studies for which individual BDG data were available ( Supplementary Figure 1 ). 12 , 18–55 Two of these cohorts accounted for a substantial number of cases ( n = 23, 31.5%). 12 , 43 In total, 73 cases of proven or probable IF in patients with EORTC–MSGERC host factors were included.…”

“… 12 , 18–55 Two of these cohorts accounted for a substantial number of cases ( n = 23, 31.5%). 12 , 43 In total, 73 cases of proven or probable IF in patients with EORTC–MSGERC host factors were included. The characteristics of the patients and IF cases are described in Table 1 .…”

“… 5 , 7 , 8 , 77 , 78 However, there is currently no specific or validated assay for the diagnosis of IF or IS, although the development of specific PCR looks to be a promising approach. 12 …”

“…Of note, these data were mainly derived from two case-series (Nucci et al and Dellière et al) displaying very distinct results with GM sensitivity of 77% (10/13 cases) and 0% (0/10 cases), respectively. 12 , 43 Such discrepancies might be related to the type of Fusarium spp. with better GM sensitivity in studies where F. solani predominates and lower sensitivity when there is a majority of other Fusarium spp.…”

“…detection in serum has been developed with promising results. 12 Although the GM test displays some cross-reaction with Fusarium spp., variable sensitivity results (10%–80%) for the diagnosis of IF in serum have been reported. 12 , 13 …”