title: Detection of Chlamydia trachomatis by isothermal ramification amplification method: a feasibility study.
abstract: Chlamydia trachomatis is the leading cause of sexually transmitted disease in the United States. Effective screening for this agent can facilitate prompt treatment and prevent its sequelae. The recent introduction of liquid-based cytology has made possible the simultaneous screening of cervical intraepithelial lesions and detection of C. trachomatis in a single collection vial. In this study we determined whether cytological fluid could support DNA-based amplification for the detection of C. trachomatis. Three methods were compared, including ramification amplification (RAM), real-time PCR with molecular beacon, and Abbott's ligase chain reaction (LCx). RAM is a novel, recently introduced, isothermal DNA amplification technique that utilizes a circular probe for target detection and achieves exponential amplification through the mechanism of primer extension, strand displacement, and ramification. Our results show that RAM can detect as few as 10 C. trachomatis elementary bodies in less than 2 h, comparable to results with real-time PCR. Thirty clinical specimens collected in PreservCyt solution were tested by LCx, real-time PCR, and RAM. Among 30 specimens, 15 were positive by PCR and LCx and 14 were positive by RAM. One specimen missed by RAM had an inadequate amount of residual cellular material. Our results show that nucleic acid amplification methods can serve to detect C. trachomatis and presumably other sexually transmitted agents in cytological fluid and that the RAM assay can be an alternative to PCR and LCx because of its simplicity and isothermal amplification.
authors.affiliation: Department of Pathology, Mount Sinai School of Medicine, New York University, New York, New York 10029, USA.
authors.forename: Wandi
authors.initials: W
authors.lastname: Zhang
authors.forename: Menashi
authors.initials: M
authors.lastname: Cohenford
authors.forename: Brian
authors.initials: B
authors.lastname: Lentrichia
authors.forename: Henry D
authors.initials: HD
authors.lastname: Isenberg
authors.forename: Elkin
authors.initials: E
authors.lastname: Simson
authors.forename: Hengjin
authors.initials: H
authors.lastname: Li
authors.forename: Jizu
authors.initials: J
authors.lastname: Yi
authors.forename: David Y
authors.initials: DY
authors.lastname: Zhang
mesh_terms: D001826:Body Fluids / Q000382:microbiology; D002584:Cervix Uteri / Q000382:microbiology; D002690:Chlamydia Infections / Q000382:microbiology*; D002692:Chlamydia trachomatis / Q000235:genetics / Q000302:isolation & purification*; D015342:DNA Probes / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D006801:Humans; D022521:Ligase Chain Reaction; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods; D013696:Temperature
chemical_list: D015342:DNA Probes; D004269:DNA, Bacterial