Evaluation of the new COBAS TaqMan CT test v2.0 and impact on the proportion of new variant Chlamydia trachomatis by the introduction of diagnostics detecting new variant C trachomatis in Orebro county, Sweden

Hadad, Ronza; Fredlund, Hans; Unemo, Magnus

doi:10.1136/sti.2008.033142

Cited by 17 publications

(16 citation statements)

References 28 publications

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“…Using a combined reference standard to define true-positive samples, we found that 9.1% of the 1,632 consecutive male and female urine samples examined were positive for C. trachomatis. The percentage of positive samples is in accordance with the observed Chlamydia-positive sample rate in different areas of Sweden (1,5) and with the findings of a previous study comprising samples from the same part of Sweden (2). The new variant strain constituted 24% of the C. trachomatis-positive samples.…”

Section: Discussionsupporting

confidence: 73%

Comparison of the Abbott RealTi m e CT New Formulation Assay with Two Other Commercial Assays for Detection of Wild-Type and New Variant Strains of Chlamydia trachomatis

2010

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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 A new variant of Chlamydia trachomatis with a deletion in the cryptic plasmid has been described in Sweden (3, 4). In a previous study. we compared the Gen-Probe Aptima Combo 2 (AC2) and Aptima CT assays, directed against different rRNA targets of C. trachomatis, with the Abbott m2000 real-time PCR assay and the Roche Cobas Amplicor CT assay. The two latter assays both target a sequence within the area deleted in cryptic plasmid of the new variant (2). We used routine samples from females and males to confirm that the new variant strain was present in one-fourth of the C. trachomatis-positive samples from the Malmö area in Sweden and that the two assays targeting the cryptic plasmid were unable to detect the plasmid mutant (2). Modifications of the Abbott m2000 and Roche Cobas assays have now been released; each consists of a duplex PCR with different targets in C. trachomatis. The new formulation of the m2000 real-time PCR adds a different target region in the cryptic plasmid to the original plasmid PCR test, and the new version 2 of the Roche Cobas TaqMan CT assay combines the original plasmid PCR with a PCR targeting the omp1 gene in C. trachomatis.The aim of this study was to compare and assess the analytical performance of the Abbott RealTime CT new formulation assay (Abbott m2000 real-time PCR clinical diagnostic system) with those of version 2 of the Roche Cobas TaqMan CT test and the Gen-Probe Aptima Combo 2 assay for clinical samples from a population with a high rate of the plasmid mutant strain. MATERIALS AND METHODSConsecutive first-catch urine samples submitted to the Department of Clinical Microbiology, Malmö University Hospital, Malmö, Sweden, and received from Monday to Thursday, from May 2008 to June 2008, were included in the study. Samples (n ϭ 1,632) were from male and female patients undergoing routine screening for C. trachomatis. Upon arrival, aliquots were transferred to the Gen-Probe and Abbott collection devices according to the respective package insert...

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Section: Discussionsupporting

confidence: 73%

Comparison of the Abbott RealTi m e CT New Formulation Assay with Two Other Commercial Assays for Detection of Wild-Type and New Variant Strains of Chlamydia trachomatis

2010

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“…However, most of the participating laboratories are in the UK (see Table 1). For surveillance and educational purposes, a blinded EQA specimen (Specimen 9119 in UK NEQAS Distribution 2402, issued in January 2009, as well as blinded specimens of three wildtype C. trachomatis strains) containing the nvCT, 1.67-3x10 4 elementary bodies per ml of reconstituted lyophilised specimen, was prepared as previously described [10]. Vacuum integrity and moisture content (<2%) of the freeze-dried specimen were validated and approved before distribution to all 283 participants.…”

Section: Methodsmentioning

confidence: 99%

“…Subsequently, nvCT was identified in high proportions (10-65%) in most counties across Sweden. The affected NAATs were used in two thirds of the Swedish counties, and many thousands of false negative samples were reported [3][4][5]. Previous studies, using ompA gene sequencing and a new multilocus sequence typing (MLST), showed that the nvCT seems to be of clonal nature, belonging to genotype E and displaying a unique MLST sequence type [3,5].…”

Section: Introductionmentioning

confidence: 99%

“…Both Abbott Laboratories and Roche Diagnostics have now designed new sensitive and specific dual-target assays, namely the Abbott RealTime CT/NG (Abbott; new version, CE mark-certified in January 2008) that targets another sequence of the cryptic plasmid in addition to the sequence affected by the nvCT deletion, and the Cobas TaqMan CT v2.0 (Roche; CE mark-certified in June 2008) that detects the chromosomal ompA gene in addition to the sequence affected by the nvCT deletion [4]. Despite active surveillance and a number of studies performed in many countries [6], only sporadic cases of nvCT have so far been reported outside Scandinavia, e.g.…”

Section: Introductionmentioning

confidence: 99%

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Can the Swedish new variant of Chlamydia trachomatis (nvCT) be detected by UK NEQAS participants from seventeen European countries and five additional countries/regions in 2009?

et al. 2009

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“…Not only are these assays highly sensitive and specific, these can be easily implemented in a high throughput laboratory [133,[135][136][137][138].…”

Section: Defining the New "Gold Standard" Assaymentioning

confidence: 99%

Diagnosis of Chlamydia trachomatis Infection

Visser¹,

Hoosen²

2012

Chlamydia

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Evaluation of the new COBAS TaqMan CT test v2.0 and impact on the proportion of new variant Chlamydia trachomatis by the introduction of diagnostics detecting new variant C trachomatis in Orebro county, Sweden

Cited by 17 publications

References 28 publications

Comparison of the Abbott RealTi m e CT New Formulation Assay with Two Other Commercial Assays for Detection of Wild-Type and New Variant Strains of Chlamydia trachomatis

Comparison of the Abbott RealTi m e CT New Formulation Assay with Two Other Commercial Assays for Detection of Wild-Type and New Variant Strains of Chlamydia trachomatis

Can the Swedish new variant of Chlamydia trachomatis (nvCT) be detected by UK NEQAS participants from seventeen European countries and five additional countries/regions in 2009?

Diagnosis of Chlamydia trachomatis Infection

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