Direkte detektion af Streptococcus agalactiae ved brug af automatiseret GenomEra CDXTM

Lone Elisabet Dons, Khaled Ghatian, Antti-Heikki Tapio

    Publikation: Konferencebidrag uden forlag/tidsskriftAbstraktForskningpeer review

    1 Downloads (Pure)


    Direct detection of Streptococcus agalactiae using the automated GenomEra CDXTM
    Khaled Ghathian, Lone Dons and Antti-Heikki Tapio
    Dept. of Clinical Microbiology, Hvidovre University Hospital, Copenhagen, Denmark
    Streptococcus agalactiae (GBS) is a pathogenic bacterium which is the most common cause of early-onset sepsis and invasive infections in pregnant women and it is associated with high morbidity and mortality rates. The rate of colonization of GBS in women varies between 10-30 % that is why the GBS colonization is in most cases asymptomatic. In our department, we detect GBS by direct plate culturing on 5 % blood agar and overnight incubation in CO2 incubator, where clinical sensitivity and specificity can be low. The GenomEra CDXTM GBS assay (ABACUS) can detect GBS from enriched broth media in less than one hour. The early detection of GBS can complement the culture protocols by increasing the diagnostic sensitivity. Therefore, efficient screening and identification of pregnant women colonized with GBS is important and need a rapid and reliable method for the detection of GBS.
    We studied 130 vaginal swabs from women (18-45 years old). The study was a prospective clinical study where the clinical performance of the GenomEra CDXTM GBS assay was compared to an established method. The reference method used in this study was the subculture of the enriched LIM-broth (Copan) on 5 % horse blood (Statens Serum Institut) and ChromIDTMStreptoB (Biomérieux) agar plates, which were incubated for 18–24 hours at 35–37 0C with 5 % CO2. Suspected GBS colonies (both hemolytic and non-hemolytic) were verified with MALDI-TOF mass spectrometry. For detection by GenomEra CDXTM GBS assay, all vaginal swabs were incubated in LIM broth (Copan) for 4 hours and overnight (24 hours). After the incubation 20 μl sample was taken from the culture for the GenomEra GBS assay sample preparation and MALDI-TOF procedure.
    In total, 130 vaginal swabs were analyzed, but 50 (no.1-50) vaginal swab samples were excluded due to contamination and 80 (no. 51-130) samples were used in calculation of sensitivity and specificity. Among the 80 samples, 36 GBS and 44 non-GBS were detected by the reference method. Detection sensitivity for GenomEra CDXTM GBS (4 hours and 24 hours procedure) were 94.4 (34/36) % and 100 (36/36) %, respectively. Six false-positive GBS results (GenomEra CDXTM 4 hour procedure) and nine false-positive GBS results (GenomEra CDXTM 24 hour procedure) were obtained from non-GBS-containing swabs, yielding a specificity of 81.8 % and 79.6 %, respectively.
    Reliable and simplified direct detection of GBS were available within one hour after 4 hours incubation in enriched LIM-broth by the GenomEra CDXTM .
    Bidragets oversatte titelDirekte detektion af Streptococcus agalactiae ved brug af automatiseret GenomEra CDXTM
    Antal sider1
    StatusUdgivet - 2016
    Begivenhed26th European Congress of Clinical Microbiology and Infectious Diseases - Amsterdam, Holland
    Varighed: 9 apr. 201612 apr. 2016
    Konferencens nummer: 26th


    Konference26th European Congress of Clinical Microbiology and Infectious Diseases


    • bioanalytikeruddannelsen
    • Streptococcus agalactiae
    • detektion