A multiplex assay of Trichomonas vaginalis, Chlamydia trachomatis and Neisseria gonorrhoeae infections in genital specimens.

Introduction: A significant proportion of patients with Sexually Transmitted Infections (STIs) are coinfected with multiple pathogens. We report here development of a multiplex PCR for simultaneous detection of Chlamydia trachomatis (C.trachomatis), Neisseria gonorrhoeae (N.gonorrhoeae) and Trichomonas vaginalis (T.vaginalis) in genital specimens from women.

Methodology: After detection of the organisms by routine techniques including PCR, culture and direct smear, multiplex-PCR was optimized to detect ompI gene of CT, parC of NG, ITS ribosomal RNA of TV as target genes. The limit of detection (LOD) was determined using serially diluted genomic DNA from known number of each pathogen.

Results: Totally 300 volunteers with mean age of 36.5 ±7.03 years were included and 266 (88.7%) had genitourinary clinical manifestations. Of 300 women, 150 (50.0%) were infected. Of them, 17 (5.7%) had N. gonorrhoeae, 98 (32.7%) T. vaginalis and 35 (11.7%) C. trachomatis. Multiplex-PCR revealed a total of 10 coinfections (3.3%) including 2 specimens of C. trachomatis/ N. gonorrhoeae, 3 specimens of C .trachomatis/ T. vaginalis and 5 specimens of N. gonorrhoeae/T. vaginalis coinfections. The sensitivity and specificity of multiplex-PCR for detecting N. gonorrhoeae were 100% and 98.59% (279 of 283) respectively and, for C. trachomatis and T. vaginalis were 100%. The LOD was 0.1 pg of DNA for C. trachomatis and N. gonorrhoeae, and 1.5 pg for T. vaginalis.

Conclusions: The performance of this multiplex-PCR makes it a sensitive, rapid and affordable technique in clinical laboratory for simultaneous detection of STIs.