Droplet digital PCR (ddPCR) for the detection and quantification of Ureaplasma spp.

BACKGROUND Ureaplasma spp. are associated with various infectious diseases in females, but there is still limited evidence regarding whether they are related to nonspecific cervicitis. The aim of this study was to develop and evaluate a digital droplet PCR (ddPCR) assay for the detection and quantification of Ureaplasma spp. in cervical swabs. METHODS A total of 267 non-specific cervicitis (NSC) patients and 195 asymptomatic females were included in this study. We produced standard curves for Ureaplasma spp. to evaluate the analytical performance of the ddPCR assay. Then, we detected and quantified the bacterial load of Ureaplasma spp. in cervical swabs. RESULTS The prevalences of U. parvum were 37.8% (101/267) and 29.7% (58/195),  U. urealyticum were 9.0% (24/267) and 8.7% (17/195) in the NSC group and control group, respectively. In addition, the median copy number of U. parvum was 2.5 × 104 copies/ml (n = 101) in the NSC group and 9.2 × 103 copies/ml (n = 58) in the control group. The U. parvum load in the NSC group was significantly higher than that in the asymptomatic individuals (P < 0.001). whereas the median load of U. urealyticum was 8.4 × 103 copies/ml (n = 24) and 1.4 × 103 (n = 17) copies/ml in the two groups, respectively, , the difference was not statistically significant (P = 0.450). CONCLUSIONS Our study is the first to develop a droplet digital PCR (ddPCR) method for the detection and quantification of Ureaplasma spp. in clinical samples, and the method has excellent analytical performance and a wide range of clinical application prospects.