title: Comparison of the Abbott RealTime CT new formulation assay with two other commercial assays for detection of wild-type and new variant strains of Chlamydia trachomatis.
abstract: In an analytical-method comparison study of clinical samples, the Abbott RealTime CT new formulation assay (m2000 real-time PCR), consisting of a duplex PCR targeting different parts of the cryptic plasmid in Chlamydia trachomatis, was compared both with version 2 of the Roche Cobas TaqMan CT assay, comprising a duplex PCR for a target in the cryptic plasmid and the omp1 gene, and with the Gen-Probe Aptima Combo 2 assay (AC2) targeting the C. trachomatis 23S rRNA molecule. First-catch urine samples from Sweden were tested in Malmö, Sweden, for C. trachomatis with the m2000 real-time PCR assay and with an in-house PCR for the new variant C. trachomatis strain with a deletion in the cryptic plasmid. Aliquots of the urine samples were sent to Aarhus, Denmark, where they were further examined with the TaqMan CT and AC2 assays. A positive prevalence of 9.1% (148/1,632 urine samples examined) was detected according to the combined reference standard. The sensitivities and specificities of the three assays were as follows: for the Abbott m2000 assay, 95.3% (141/148) and 99.9% (1,483/1,485), respectively; for the Roche TaqMan assay, 82.4% (122/148) and 100.0% (1,485/1,485); and for the Gen-Probe AC2 assay, 99.3% (147/148) and 99.9% (1,484/1,485). The plasmid mutant strain was detected in 24% (36/148) of the C. trachomatis-positive samples. There is a difference in sensitivity between the new formulations of the Abbott and the Roche assays, but both assays detected the wild-type and new variant C. trachomatis strains equally well.
authors.affiliation: Department of Clinical Microbiology, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark. jkm@dadlnet.dk
authors.forename: Jens Kjølseth
authors.initials: JK
authors.lastname: Møller
authors.forename: Lisbeth Nørum
authors.initials: LN
authors.lastname: Pedersen
authors.forename: Kenneth
authors.initials: K
authors.lastname: Persson
mesh_terms: D000328:Adult; D001431:Bacteriological Techniques / Q000379:methods*; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000235:genetics / Q000302:isolation & purification*; D003718:Denmark; D005260:Female; D006801:Humans; D008297:Male; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D013548:Sweden; D014556:Urine / Q000382:microbiology; D055815:Young Adult
chemical_list: D011933:Reagent Kits, Diagnostic