Eur J Clin Microbiol Infect Dis (2006) 25: 167–174
DOI 10.1007/S10096-006-0112-4
ARTICLE
C. Moore
.
M. Valappil
.
S. Corden
.
D. Westmoreland
Enhanced clinical utility of the NucliSens EasyQ RSV A+B Assay
for rapid detection of respiratory syncytial virus in clinical
samples
Published online: 14 March 2006
# Springer-Verlag 2006
Abstract The aim of the present study was to compare
traditional methods for the detection of respiratory syncy-
tial virus with a newly developed commercial assay based
on real-time nucleic acid sequence based amplification.
Respiratory syncytial virus is a major cause of severe
respiratory infection in infants and in certain groups of
older children and adults. Treatment options are limited,
but a rapid diagnosis improves patient management and
infection control. The rapid diagnosis of respiratory
syncytial virus currently relies on antigen detection assays.
These tests are limited to use in certain good-quality types
of samples, which are rarely obtained from adult patients.
Molecular-based assays for the detection of respiratory
syncytial virus are shown to be highly sensitive, specific,
and more rapid than cell culture techniques. This retro-
spective study compared traditional laboratory techniques
for the detection of respiratory syncytial virus in 508
respiratory samples collected during the winter months of
2003–2004 against the recently developed, commercially
available NucliSens EasyQ Respiratory Syncytial Virus A
+B assay (bioMérieux, Marcy l’Etoile, France), which is
based on real-time nucleic acid sequence based amplifica-
tion using molecular beacons and an internal control. Using
traditional techniques, the prevalence of respiratory syn-
cytial virus in the samples tested was found to be 21%.
Using the real-time nucleic acid sequence-based amplifi-
cation assay, an additional 41 samples from patients with a
clinically diagnosed respiratory illness were found to be
positive for respiratory syncytial virus. The NucliSens
EasyQ assay was shown to be sensitive and specific for the
detection of respiratory syncytial virus A+B in different
types of respiratory samples. Moreover, the time required to
complete the assay was <4 h, so results could be obtained
on the same day as sample receipt in the laboratory.
Introduction
Respiratory syncytial virus (RSV) is the leading cause of
lower respiratory tract infection in infancy and early
childhood and is acknowledged as being an important
cause of morbidity in certain adult populations [1, 2]. It is
the single most common cause of bronchiolitis in infants,
with around 2% of those infected requiring hospitalisation
in developed countries annually [1, 3]. In adult popula-
tions, it is estimated that up to 15% of pneumonia
hospitalisations during the winter months are caused by
RSV infection [2].
RSV epidemics are highly predictable annual occur-
rences. In temperate climates, the ‘‘RSV season’’ generally
peaks during November to March, with RSV rarely isolated
during the summer. In tropical or subtropical regions, an
increased incidence of RSV occurs during rainy seasons
[4]. Two subtypes of RSV exist, A and B, which co-
circulate within the population. Epidemiological studies
suggest that RSV type A may be associated with a more
severe infection than RSV type B, although this has not
been proven conclusively [1, 5, 6]. No vaccine is currently
available, and treatment options for RSV are limited. A
rapid diagnosis of RSV, however, allows for appropriate
patient management and infection control measures [7].
RSV is a labile virus, which has implications for the
laboratory diagnosis of infection, particularly if the method
of choice is cell culture [8]. The cell line used in most
routine diagnostic laboratories for isolation of RSV is HEp-
2, with viral growth being identified by the characteristic
syncytia (giant cell) formation from which the virus derives
its name. Whilst RSV can be isolated from most respiratory
samples, more rapid results can be achieved by using an
RSV antigen detection assay such as direct immunofluo-
rescence of washed epithelial cells obtained from clinical
samples such as nasopharyngeal aspirates and bronchoal-
C. Moore (*)
.
M. Valappil
.
S. Corden
.
D. Westmoreland
Wales Specialist Virology Centre, National Public Health
Service for Wales Microbiology Cardiff,
University Hospital of Wales, Heath Park,
Cardiff, CF 14 4XW, UK
e-mail: catherine.moore@nphs.wales.nhs.uk
Tel.: +44-29-20742046
Fax: +44-29-20743000