First evaluation of polymerase chain reaction assays used for diagnosis of Mycoplasma genitalium in Russia

Background Diagnosis of Mycoplasma genitalium is entirely based on nucleic acid amplification tests (NAATs). In Russia, several M. genitalium polymerase chain reaction (PCR) assays have been developed; however, any evaluation of their performance has never been performed. Objective To assess the performance of five PCRs developed and currently used in Russia for diagnosis of M. genitalium. Materials and methods Vaginal swabs and first voided urine samples (FVUs) from 281 females and urethral swabs and FVUs from 125 males were analysed using three conventional PCRs and two real-time PCRs developed by three Russian companies. As reference tests, a real-time PCR targeting the MgPa adhesin gene was used; positive results were confirmed by two conventional PCRs targeting the 16S rRNA gene and MgPa gene, respectively. For evaluation of detection limits and analytical specificities, a blinded control panel consisting of dilutions of six strains of M. genitalium and 14 other Mycoplasma species was tested. Results The prevalence of M. genitalium was 2.5% among females and 9.6% among males. The highest sensitivity (71.4-100% in different specimens) was exhibited by one real-time PCRs. Conventional PCRs from two manufacturers failed to detect M. genitalium in any of the seven positive female FVUs. All tests had a 100% clinical specificity; however, one cross-reacted with Mycoplasma pneumoniae. Conclusions Only one of the five Russian PCRs displayed reasonable sensitivity for all specimen types, but the specificities of all assays were high. Accordingly, improvements regarding sensitivity of all the tests are needed. However, larger studies, including other populations, evaluating these assays are crucial.