Journal of Clinical Virology - Volume 82 - Supplement 1 - September 2016

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S42 Abstracts / Journal of Clinical Virology 82S (2016) S1–S142
Clinical positive samples: The PCR efficiency using RealStar®
CMV PCR Kit 1.0 was in the range 102.2–105.4, while the PCR effi-
ciency using Quidel CMV kit was in the range 111.6–124.2. Six of
the 13 samples showed ≥10 times higher viral load using Quidel
CMV kit than using RealStar® CMV PCR Kit 1.0.
Conclusions: Overall, both CMV assays performed well at our
laboratory. Viral load measured by RealStar® CMV PCR Kit 1.0 were
very close to the expected results from both QCMD panel and 1st
WHO standard, while viral load measured by Quidel CMV kit were
about one Log 10 IU/ml higher than expected. The same was seen
for the clinical samples, where Quidel CMV kit resulted in a higher
viral load compared to RealStar® CMV PCR Kit 1.0 for almost half
the samples. Based on the comparison it appeared that using Quidel
CMV kit would result in a higher level of viral load compared to
RealStar® CMV PCR Kit 1.0. This could potentially influence treat-
ment of patients.
Abstract no: 304
Presentation at ESCV 2016: Poster 42
Performance of the IDS-iSYS “walk away”
immunoassay system for the assessment of
immunity to rubella virus and cytomegalovirus
M. Baccard Longere ∗, J. Lupo , J. Tolenaere ,
C. Delmas orand
1 Laboratoire de Virologie, CHU Grenoble, Université
Grenoble Alpes, France
2 Laboratoire de Virologie, CHU Grenoble, Institut de
Biologie Structurale Université Grenoble Alpes,
France
3 Immunodiagnostic Systems, Paris France
Background: Reliable and easy screening of IgG and IgM anti-
bodies against Rubella virus (RV) and Cytomegalovirus (CMV) is
of crucial importance in pregnant women in order to differentiate
absence of infection, past infection, primary infection or rein-
fection. Here we report the performance of a new commercial
automated immunoassay system, IDS-iSYS, for the assessment of
immunity to RV and CMV on a large panel of samples.
Material and methods: Two panels of 168 sera (162 patients)
and 350 sera (331 patients) were retrospectively selected from our
university hospital routine screening for RV and CMV serology,
respectively.
The immunoassays routinely used in our laboratory for the
detection of IgG (± IgG avidity) and IgM antibodies against RV
and CMV (Enzygnost® Immunoassay, Siemens Healthcare Diagnos-
tics; Ela test PKS® MedacDiagnostics and Vidas® assay bioMerieux)
were used as “reference tests” to classify the samples as (i) seroneg-
ative (IgG and IgM negative); (ii) past infection (IgM neg, IgG pos
with high IgG avidity); primary infection (IgM pos and IgG pos with
low IgG avidity) or reinfection or reactivation (IgM pos and IgG pos
with high IgG avidity
The determination of RV and CMV IgG avidity with the IDS-iSYS
system was also compared to the IgG avidity assessed with the
Vidas assay. Sensitivity (Sens.), specificity (Spec.) and concordance
(Conc.) of the IDS-iSYS parameters were compared to the reference
tests.
Results: RV panel-sera: 50 seronegative, 67 past infections, 36
primary infections, 1 reinfection. The IDS-iSYS IgG Sens., Spec.
and Conc. compared to the Enzygnost IgG assay were 97.4% (95%
IC:96.4–98.9), 100% (95% IC:92.9–100) and 96.7 (95% IC:92.4–98.6),
respectively. The IDS-iSYS IgM Sens., Spec. and Conc. compared
to Vidas IgM assay were 100% (95%: CI 89.2–100), 100% (95%: CI
97.1–100) and 100% (95% CI: 97.6–100). The IDS-iSYS IgG avidity
assay was tested on 24 and 52 sera with respectively a low or high
aviditywith the Vidas avidity assay and the overall Conc. was 94.8%.
The specificity of the IDS-iSYS IgG avidity assay to exclude a primary
infection of less than 2 months was 100%.
CMV panel-sera: 116 seronegative, 130 past infections, 101 pri-
mary infections. The IDS-iSYS IgG Sens., Spec. and Conc. compared
with the Enzygnost IgG assay were 98.7(95% CI: 96.2–99.6), 99.2%
(95% CI: 95.2–99.9) and 98.9 (95% CI: 97–99.6), respectively. The
IDS-iSYS IgMSens., Spec. and Conc. were compared to the ELAT Test
PKS Medac IgM assay as reference test. The Spec. was 100% (95%:
CI 96.7–100) both for the seronegative panel and the past infection
panel (CI 95%: 98.4–100). The Sens was 94.3 (95%:CI 87.3–97.6).
The Conc was 95.4% (CI 95%: 92.6–97.2). The IDS-iSYS IgG avidity
assay was tested on 96 and 107 sera with respectively a low or high
avidity with the Vidas avidity assay and the overall Conc. was 92.6%
(95%: CI 88–95.5). The specificity of the IDS-iSYS IgG avidity assay
to exclude a primary infection of less than 3 months was 100%
Conclusion:The IDS-iSYS is a real “Walk-Away System”; easy to
use, fast and secure and appears to offer new reliable commercial
immunoassays for the detection of IgG and IgM antibodies against
Rubella virus and Cytomegalovirus.
Abstract no: 31
Presentation at ESCV 2016: Poster 43
Characterization of oseltamivir-resistant
population dynamics in immunosuppressed
patients with prolonged excretion using ddPCR
platform and comparison with deep sequencing
analysis
M. Pichon ∗, A. Gaymard , L. Josset ,
M. Valette , G. Millat , B. Lina , V. Escuret
1 Virology Department, University Hospital of Lyon,
France
2 Virpath, Inserm U1111 – CNRS UMR 5308, Lyon,
France
3 Molecular Biology Department, University Hospital
of Lyon, France
Introduction: TheH275Ymutation inneuraminidase (NA) is the
most frequently encounteredmutation responsible for oseltamivir-
resistance in A(H1N1) influenza viruses (IV). Digital Droplets PCR
(ddPCR) is a rising method to explore single nucleotide poly-
morphism (SNP). ddPCR is known to have higher sensitivity than
real-time PCR (qPCR) and ability to obtain absolute quantifications
for subpopulations. After comparison of ddPCR, qPCR and deep
sequencing (NGS) performances, we explored the resistant sub-
population kinetics for two immunocompromised patients with
sustained shedding of A(H1N1)pdm09.
Methods: Overall 90 samples were analysed by two PCR tech-
nics using same primers and probes. (i) qPCR was performed using
ABI 7500 platform (Applied Biosystem, USA). Results were analysed
using SDS software. (ii) ddPCR assay was carried out according to
manufacturer’s instructions using the QX100 ddPCR platform (Bio-
rad laboratories, USA). ddPCR resultswere analysed by Quantasoft®
software. We strengthened our results by a NGS assay using PGM
platform (Lifetechnologies, USA). Reads were analysed using Sam-
Tools software and pileup files were analysed to evaluate the
proportion of each variant of interest. Discrimination performances
and sensitivity of the ddPCR assay were evaluated on mixes of wild
type (WT) H275-NA and mutated Y275-NA-coding segments at
different concentrations. Then, we evaluated mutation frequency