Abstract: Chlamydia trachomatis infection is one of the prevalent sexaully transmitted diseases(STD) of the urogenital tract. A total of 110 clinical specimens from patients attending STD clinics were detected by using polymerase chain reaction (PCR), and were compared with direct fluorescent assay (DFA). Oligonucleotide primers were designed to amplify a fragment within the conserved region of a major outer membrane protein(MOMP) gene of Chlamydia trachomatis, the positive rate of PCR was 59.1% (65/110), and negative rate 40.9% (45/110). The positive rate of DFA was 39.1% (43/110), and negative rate were 60.9% (67/110). The Chlamydia trachomatis positive rates were significantly different between PCR and DFA (P<0.01). The relationship between the course of disease and the detection rates by PCR and DFA was analyzed. The positive rate of PCR was not related to the course of disease (P>0.05),but the positive rate of DFA was related to the course of the disease, the longer the course of disease(>2 months) the lower the positive rate of DFA (P<0.01). It is the authers′ opinion that PCR is useful for those patients with long course of disease and negative DFA result.

Key words: Chlamydia trachomatis, Polymerase chain reaction, Direct fluorescent assay