Molecular Detection and Genotyping by Sequencing

Detection of LGV Chlamydia serovars by real-time PCR on confirmed C. trachomatis samples and genotyping by direct sequencing of confirmed LGV serovars.

Chlamydia positive culture or positive rectal, endocervical, urethral, urine, biopsies as well as specimens in buffer (such as Roche Cobas CTNG buffer, APTIMA buffer. Other specimen types can be considered upon request. The minimum volume required is 1mL.

Swab or cytobrush

Place cytobrushes or swabs in 2 mL of transport medium. Specimens may be stored and shipped refrigerated to NML within 48h of sample collection or must be stored and shipped frozen. Fresh biopsies must be stored frozen at all times and shipped on dry ice.

Shipping of specimens shall be done by a TDG certified individual in accordance with TDG regulations. For additional information regarding classification of specimens for the purposes of shipping, consult either Part 2 Appendix 3 of the TDG Regulations or section 3.6.2 of the IATA Dangerous Goods Regulations as applicable.

This service is offered for LGV suspected cases on positive C. trachomatis samples only. Specimens for C. trachomatis screening are not accepted unless part of pre-arranged collaborative study.

Completed “Viral STI, Polyoma and Herpesvirus Testing” requisition form including sender lab name, address and telephone number, patient identifier, date of birth or age, sex, specimen reference #, type of specimen, date collected, test requested, buffer type, reason for testing and any other relevant clinical information.

Please contact the VSTI lab if you wish to use an excel sheet format requisition to accommodate batch submission of specimens.

N/A

Detection of LGV Chlamydia in Chlamydia positive specimens is performed by a multiplex real time PCR assay (1). The analytical sensitivity for the detection of LGV is between 10 and 100 copies/reaction while the detection for the cryptic plasmid is about 100 copies/reaction. The serovar is confirmed by amplification and sequencing of the ompA gene and the pmpH gene. Optimization of the assay to include the pgp3 gene is in progress.

Please note that this method is less sensitive than diagnostic kits available and is not intended for Chlamydia trachomatis screening.

10 calendar days for LGV detection and 21 calendar days for LGV genotyping.  Please contact lab to inquire about shorter turnaround time.

1. Chen CY, Chi KH, Alexander S, Ison CA, Ballard RC. A real-time quadriplex PCR assay for the diagnosis of rectal lymphogranuloma venereum and non-lymphogranuloma venereum Chlamydia trachomatis infections. Sex Transm Infect. 2008 Aug;84(4):273-6.
2. Smit PW, Cornelissen AR, Bruisten SM (2020) Reduction of non-typeable results using a plasmid oriented Lymfogranuloma venereum PCR for typing of Chlamydia trachomatis positive samples. PLoS ONE 15(6): e0233990. https://doi.org/10.1371/journal.pone.0233990