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PLEX-ID Technology as a Single Tool for the Detection and Typing of Microbiological
Infections in Immuno-Compromised Patients
Jérôme Le Goff 1 , Linda Feghoul 1 , Jean Menotti 1 , Jean Luc Donay 1 , Séverine Mercier-Delarue 1 ,
Jean Louis Pons 1 , Marcus Picard-Maureau² and François Simon 1
1- Université Paris-Diderot, Hôpital Saint-Louis, Paris, France
2- Abbott Ibis Biosciences, 65205 Wiesbaden, Germany
Introduction : the PLEX-ID technology (Abbott Ibis Biosciences), combining broad-range multiwell
PCR and mass spectrometry enables the detection and identification of a large spectrum of pathogens in
a single test. The PLEX-ID analysis is based on a broad multiwell PCR followed by an electrospray
ionization of the generated amplicons to analyse their time of flight by mass spectrometry. The weight
of the amplicons allows to determine their base compositions. The PLEX-ID technology allows to
identify large a variety of pathogens from various sample types (blood, plasma, biopsy, CSF, BAL..) in a
few hours, enabling the resolution of mixtures and according to the assay, a high resolution in
genotyping. A large panel of assays is available, from public health and biothreat to medical diagnostics.
That integrated solution allows the analysis of up to 15 x 96-well plates over 12 hours for a total
throughput of up to 250 samples per day.
We evaluated in our university hospital, specialized in Hematopoietic stem cells (HSC) and kidney
transplants, the performances and reliability of the PLEX-ID technology.
Objectives : to compare the accuracy and the rate of infections detected by PLEX-ID clinical assays and
routine standard methods and to compare the turnaround times of both procedures.
Methods : We evaluated 3 different clinical PLEX-ID assays for medical microbiology.
- The Viral IC assay detects 174 RNA and DNA viruses species and 2611 subspecies. We first analyzed
275 frozen samples from 54 children and 11 adults infected with Adv (245) and from non-infected
patients (30). In a second study, we parallelized the routine vs PLEX-ID in 79 fresh samples from HSC
and kidney transplants.
- The BAC Detection assay identifies 6026 species of bacteria and Candida and 4 antibiotic
resistance markers ( kpc, mec A, van A, van B). Peripheral blood and catheter sampling were tested in
BACT Alert blood culture (bioMérieux) and PLEX-ID. Preliminary study included 48 samples from
adult patients.
- The Broad Fungal assay identifies 2108 species. Fresh broncho-alveolar lavages and nasopharyngal
aspirates from 25 patients were compared between fungal culture and PLEX-ID analysis.
Additional samples collected from patients with undiagnosed fever were included in the BAC and
Fungal studies.
Results : All the negative PLEX-ID results in clinical samples were negative in the routine procedure
considered as the gold standard, pointing the excellent PLEX-ID negative predictive value. A high
negative predictive value was also observed with stored plasma samples in Viral IC assay.
- Viral IC assay in Adenovirus-infected patients: ADV was detected in 96.4% of ADV positive stored
plasma. The accuracy for species identification was 0.985. Out of 29 routine-negative samples collected
from known ADV infected patients, 7 were positive with PLEX-ID. Viral loads determined with
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