Background Sexually transmitted infections are caused by a relatively well defined group of pathogens. Their individual detection using cultural and molecular techniques is time-consuming and costly. Multiplex real-time PCR is a rapid and more cost-effective alternative and allows the detection of multiple infections.

Methods We have validated the Anyplex II^TM STI-7, a semiquantitative, highly multiplexed real-time PCR kit (Seegene), using a selection of specimens positive by routine methods (culture, PCR, cytology) for at least one of the 7 different targets. Specimens were assumed to be negative for those parameters not previously tested. DNA was isolated using the easyMAG^® (bioMérieux) followed by melting curve analysis-based PCR on a CFX96^TM thermocycler (BioRad) and automatic data interpretation with the Seegene Viewer software. Discrepant results were resolved with independent molecular tests.

Results Resolved results showed 100% sensitivity and specificity for Chlamydia trachomatis (17 positive/73 negative specimens), Neisseria gonorrhoeae (13/71), Trichomonas vaginalis (6/84), Mycoplasma genitalium (18/72) and Mycoplasma hominis (30/60). For Ureaplasma species (57/30) 100% sensitivity and 93.3% specificity were observed. The STI-7 test (the only test capable of separating the two major species) revealed that among the 57 Ureaplasma-positive specimens 7 (12.3%) were positive for U. urealyticum, 39 (68.4%) for U. parvum and 11 (19.3%) for both species. Often, 2 or more targets were detected, e.g. of the 17 C. trachomatis-positive specimens 8 were positive for 1 and 7 for 2 additional organisms. Ureaplasmas were the most prevalent species being present in about 2/3 of the specimens.

Conclusion We conclude that the STI-7 multiplex PCR is a rapid and reliable test for the simultaneous detection of the most important sexually transmitted pathogens providing an efficient means for a more thorough evaluation of the clinical significance of the various organisms.