Distribution study of Chlamydia trachomatis serovars among high-risk women in China performed using PCR-restriction fragment length polymorphism genotyping.

This was one of the first epidemiological studies in China focused on genital Chlamydia trachomatis serotype distribution in high-risk female populations using omp1 gene-based restriction fragment length polymorphism analysis. One thousand seven hundred seventy cervical swab samples from women attending sexually transmitted disease clinics and female sex workers in six cities in China (Shenzhen and Guangzhou in southern China, Nanjing and Shanghai in eastern China, and Nanning and Chengdu in southwestern China) were subjected to serovar genotyping. The proportion of omp1 genes successfully amplified in 240 C. trachomatis plasmid-positive samples was 94.2% (226/240). Serotypes E (n = 63; 27.9%), F (n = 53; 23.5%), G (n = 28; 12.4%), and D (n = 25; 11.1%) were most prevalent. Though there was no significant difference in the geographic distribution of C. trachomatis, serotype E was predominant in the South (32.1%) and East (27.1%), while serotype F was predominant in the Southwest (28.3%). Serotype F infection was associated with young age and single status. Serovar G was associated with lower abdominal pain; 47.5% of asymptomatic patients were infected with serovar E. These results provide information on distribution of genital C. trachomatis serotypes among high-risk women in China and indicate that high-risk women, including those who are asymptomatic, can be infected with multiple serovars of C. trachomatis, revealing exposure to multiple sources of infection. Although the scope for generalizations is limited by our small sample size, our results showing clinical correlations with genotypes are informative.