Rapid and sensitive detection of Chlamydia trachomatis sexually transmitted infections in resource-constrained settings in Thailand at the point-of-care

Infection is often asymptomatic, causing the epidemiology to be underestimated. [...]we have developed a rapid, inexpensive, easy-to-interpret, sensitive and specific point-of-care (POC) C. trachomatis detection system, using loop-mediated isothermal amplification (LAMP) for target C. trachomatis DNA amplification, followed by gold nanoparticle probe (AuNP) for colorimetric C. trachomatis specific readout. Results Optimization of LAMP-AuNP Loop primers LF and LB, which specifically locate the dumbbell products of LAMP, allow for extra amplification of the loop amplicons. [...]a sufficient amount of amplicons for detection by GE (or AuNP) were made at the shorter assay time. The results demonstrated an LOD of 22.5 copies for PCR-GE and 45 copies for LAMP-GE and LAMP-AuNP. [...]increasing the LAMP reaction incubation from 20 to 35 minutes allowed the LOD to become consistent at 11.25 copies (S4 Fig, lane 1). The colorimetric change of the LAMP-AuNP was confirmed by UV-vis spectrophotometry [7]. [...]the LAMP-AuNP has an LOD of 45 copies when incubated for 20 minutes and 11.25 copies when incubated for 35 minutes.