Performance evaluation of a new culture colorimetric detection assay

Objective: To evaluate the performance of the culture colorimetric detection assay MYCO WELL D-ONE® (MWD-ONE), designed to detect sexually transmitted infections using real-time polymerase chain reaction (PCR) as a reference method. Materials and Methods: One hundred and ten urogenital samples were screened for Gardnerella vaginalis (GV), Trichomonas vaginalis (TV), Mycoplasma hominis (MH), Mycoplasma spp., and Ureaplasma urealyticum (UU)/Ureaplasma parvum (UP) using the MWD-ONE and real-time PCR assays Gardnerella vaginalis/Lacto-bacillus species Real-TM Quant and Anyplex II STI-7 Detection, respectively. Results: GV was detected in 33 samples by both the MWD-ONE and real-time PCR, while 6 samples gave discordant results. TV was detected by both MWD-ONE and Anyplex II STI-7 Detection kits in 3 samples, while 107 were negative. MH was detected by both methods in 5 cases, 4 samples gave discordant results, and 101 were negative. Mycoplasma genitalium (MG) was detected by Anyplex II STI-7 in 2 cases, 1 of which was detected as Mycoplasma spp. by MWD-ONE. Ten samples were positive by MWD-ONE, and 98 were negative with both assays. With regard to UU/UP, 24 cases were detected by MWD-ONE and Anyplex PCR, 25 by PCR only, 4 by MWD-ONE, and 57 tested negative with both methods. The positive predictive values (PPV) and negative predictive values (NPV) of the MWD-ONE assay for the pathogens tested were as following: GV, PPV 94.3%, NPV 94.7%; TV, PPV and NPV 100%; MH, PPV 71.4%, NPV 98.1%; Mycoplasma spp., PPV 9.1%, NPV 98.9%; and Ureaplasma spp., PPV 85.7 %, NPV 69.5 %. The agreement between the MWD-ONE and PCR was strong for GV and MH (k=0.8 and 0.7, respectively); perfect for TV (k=1); and moderate for UU/UP (k=0.4). Conclusion: MWD-ONE assay appears to be suitable for routine testing of sexually transmitted infections.