Real-time TaqMan polymerase chain reaction assays for quantitative detection and differentiation of Ureaplasma urealyticum and Ureaplasma parvum

Abstract

Evidence has been presented that the species currently known as Ureaplasma urealyticum should be separated into 2 species— Ureaplasma parvum (previously, U. urealyticum biovar 1) and U. urealyticum (previously, U. urealyticum biovar 2). Differentiation and quantification of U. parvum and U. urealyticum can provide important information of the epidemiology of Ureaplasma infections. We developed 2 real-time TaqMan polymerase chain reaction (PCR) assays that would allow rapid, specific, sensitive, quantitative detection and convenient differentiation of U. parvum and U. urealyticum. One hundred twenty-eight clinical specimens were studied and compared with results obtained by culture methods and conventional PCR. The positive rate of real-time TaqMan PCR (59.4%, 76 of 128) was higher than that of culture methods (42.2%, 54 of 128) and conventional PCR (50%, 64 of 128). Of 76 positive specimens, 86.8% (66) contained U. parvum only, 10.5% (8) contained U. urealyticum only, and 2.6% (2) contained both. The copy numbers of 11 positive specimens were in the range of 10 1 to 10 3 copies per reaction mixture, 18 in the range of 10 3 to 10 5, and 47 in the range of 10 5 to 10 8. In the future, quantitative detection and convenient differentiation of real-time TaqMan PCR assays will assist in the study of the pathogenesis and epidemiology of Ureaplasma infections.