AbstractBackgroundLittle is known about rectal Chlamydia trachomatis (CT) infection in outpatients attending sexually transmitted disease (STD) clinics in China. In this study, we aimed to explore the clinical and epidemiologic features of rectal CT infection in this population.MethodsA cross-sectional study was conducted among patients attending STD clinics in Tianjin and Guangxi provinces of China from June 2018 to August 2020. Bivariate and multivariate logistic regression analysis were developed to explore the association of different risk factors for urogenital and rectal CT infection.ResultsThe prevalence of urogenital and rectal CT was 11.2% (154/1374) and 4.9% (68/1377), respectively. The rectal CT prevalence among female and male patients was 7.8% (60/767) and 1.3% (8/610), respectively. The most common genotype in urogenital CT–positive samples was genotype E (29.9%), while the most common genotype among rectal CT–positive samples was genotype J (23.4%). More than 85% (52/60) of women infected with rectal CT were co-infected with urogenital CT. About 90.0% (36/40) of women shared similar genotypes between rectal and urogenital samples. Females and patients infected with urogenital CT were deemed to be at an increased risk for rectal CT infection. A high proportion of rectal CT infection had concurrent urogenital CT infection, especially in women, and most of the co-infections were shared among the same genotypes.ConclusionsIt would be prudent to encourage awareness and introduce detection tests and treatment strategies for rectal CT infection particularly in female patients visiting STD clinics in China.