Loop-mediated isothermal amplification on crude DNA as a point-of-care test for the diagnosis of mycoplasma-related vaginitis during early pregnancy

Abstract

Background: Mycoplasma-related vaginitis gradually has been growing as a threat in adults—genitourinary infection contributes to funisitis, spontaneous abortion, and low birth weight. Until now, use of loop-mediated isothermal amplification (LAMP) to detect Ureaplasma urealyticum (UU), Mycoplasma hominis (MH), or Mycoplasma genitalium (MG) has been reported by some researchers. However, previous studies focused on purified DNA as the template for LAMP assay, which is usually extracted via commercial kit. Methods: We developed a LAMP assay for rapid detection of UU, MH, and MG genital mycoplasmas using a simple boiling method for DNA extraction, in a cohort of pregnant women with mycoplasma-related vaginitis. We monitored amplicons with the naked eye using SYBR Green I. Results: The cohort in our study showed a prevalence of 22.6% in pregnant women, as detected by UU-LAMP assay. Compared to the polymerase chain reaction (PCR) test with purified DNA, the sensitivity of the UU-LAMP in clinical specimens with crude DNA was 87.5% (95% confidence interval [CI], 64.6%–>99.9). For crude DNA specimens, UU-LAMP was more sensitive and reliable than PCR, with a higher agreement rate (96.8%) and Youden index value (0.88). Conclusions: As a point-of-care test, LAMP is a useful, specific, and efficient way to detect genital mycoplasmas in resource-limited settings, especially for crude DNA.