P3-S1.15 The molecular diagnosis of rectal GC and CT infections using the FTA elute card for specimen collection and the real-time multiplex PCR for detection

Background To evaluate the potential use of the Whatman Indicating FTA Elute Micro Card for collection, transport, and storage of rectal swab specimens for subsequent detection of STD pathogens in MSM using a TaqMan-based real-time multiplex PCR. Methods Two rectal swabs were obtained by the physician from each participant in a study to determine carriage of STD pathogens among MSM. One of the swabs was placed into a tube containing 1 ml of Genelock transport medium and while the other swab was firmly pressed onto an FTA Card with three side to side motions held at approximately 60° angle each time. Genomic DNA was eluted from three discs (3 mm diameter) punched out of each card after storage at room temperature for up to 6 months and tested by a real-time multiplex PCR assay which simultaneously detects lymphogranuloma venereum (LGV), non- LGV, Chlamydia trachomatis (CT), and Neisseria gonorrhoeae (GC), and human DNA control. For comparison, an aliquot of sample from genelock tube was extracted using the Qiagen DNA mini kit and tested with same real-time multiplex PCR assay. Results Using purified DNA obtained from the Genelock specimens, the real-time multiplex PCR assay detected nine GC and 17 non-LGV CT; while 7 GC and 15 non-LGV CT were detected in DNA samples eluted from the FTA Cards and used directly for PCR. There were three GC and non-LGV co-infections and no LGV was detected using both specimen collection methods. A substantial number of specimens were found to be PCR inhibitory either collected in Genelock (18.3%) or on FTA Cards (15.4%). Conclusions The FTA Elute Micro Card allows stable storage and convenient transport of rectal swab specimens at room temperature. DNA can be eluted from the card with simple processes instead of numerous purification procedures for downstream real-time PCR amplification and aetiology detection. This preliminary evaluation shows the potential use of FTA Card for rectal specimen collection and PCR testing, and may also provide a cost-saving alternative to expensive international shipping of specimens on dry ice from remote study sites.