Abstract: HAN Yan, YIN Yue-ping, SHI Mei-qin, CHEN Shao-chun, XIANG Zhi, LI Hong-min. Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical Collage; National Center for Sexually Transmitted Disease Control, China Center for Disease Control and Prevention, Nanjing 210042, China Corresponding author: YIN Yue-ping, Email: yinyp@ncstdlc.org 【Abstract】 Objective To assess the prevalence of urogenital infection with and genotype distribution of C. trachomatis among female sex workers （FSWs） from different entertainment venues in Wuzhou and Hezhou cities of Guangxi Zhuang Autonomous Region. Methods A total of 810 FSWs were recruited to this study by convenience sampling from entertainment venues in Wuzhou and Hezhou cities of Guangxi Zhuang Autonomous Region from July 2009 to September 2010. Based on the venues where they solicited clients，the FSWs were classified into three tiers, i.e., high-tier, middle-tier and low-tier. Cervical swabs were collected from all of these subjects followed by detection of C. trachomatis with the Amplicor PCR test kit. Then, DNA was extracted from C. trachomatis-positive specimens and subjected to nested PCR assay targeting the ompA gene followed by bidirectional sequencing. The genotype of C. trachomatis was determined according to the sequence of ompA gene. Chi-square test was conducted to compare the urogenital infection rate and genotype distribution of C. trachomatis between different tiers of FSWs. Results Among the 805 FSWs, the prevalence rate of urogenital C. trachomatis infection was 20.0% （161/805）. Chi-square test showed that the prevalence rate of urogenital C. trachomatis infection was significantly lower in high- and middle-tier FSWs than in low-tier FSWs（χ2 = 3.97, 5.95, respectively, both P < 0.05）. Nine genotypes of C. trachomatis were identified in these FSWs, with serotype F as the most prevalent genotype （39/154, 25.3%）. Low-tier FSWs showed a higher frequency of genotype E （χ2 = 5.02，P < 0.05） but a lower frequency of genotype K （Fisher′s Exact test, P = 0.048） compared with middle-tier FSWs. Conclusions Low-tier FSWs show a high rate of urogenital infection with C. trachomatis, with serotype E as the prevalent type. Since C. trachomatis serovar E-infected patients are likely to be missed by symptom-based screening and preventive strategies, standardized screening for and efficient treatment of urogenital C. trachomatis infection should be enhanced among low-tier FSWs for the prevention of C. trachomatis transmission. 【Key words】 Chlamydia trachomatis ; Genes; Prostitution