Abstract: In order to facilitate molecular epidemiologic study of chlamydial urogenital infections,a method that aviods culture was developed to determine the serovars of Chlamydia trachomatis(CT). Polymerase chain reaction was used first to amplify a large part of the major outer membrane protien gene(omp1). The amplified DNA was then digested simultaneously with restriction endonuclease Alu I and Msp I and the resulting fragments were separated on 10% polyacrylamide gels. After silver nitrate staining, a total of 13 characteristic patterns were observed for the 15 serovars. Serovar C and J were similar in pattern, but could be distinguished by cleavage with HinfⅠ. Using Dde I and EcoRI, the patterns of serovar H and L₃ could be differentiated from each other. Analysis of 12 CT-positive clinical specimens gave the following results: 6D,2E,2F,1F/G and 1B strains. This study indicates that the omp1-based genotyping is useful for large-scale epidemiologic studies of chlamydial infections.

Key words: Chlamydia trachomatis, Outer memberane protein gene, Polymerase chain reaction, Restriction fragment length polymorphism