High Prevalence of Co-Infections by Invasive and Non-Invasive Chlamydia trachomatis Genotypes during the Lymphogranuloma Venereum Outbreak in Spain
OBJECTIVE To investigate molecular epidemiology of Chlamydia trachomatis infection among patients recruited from different clinic settings in Shenzhen, China. METHODS A total of 2534 patients from the sexually transmitted disease (STD) clinics, obstetrics and gynaecology (OBGYN) clinics and genitourinary medicine (GUM) clinics in 34 hospitals participated in the study. The C trachomatis infection was determined using COBAS Amplicor system. DNA extracted in C trachomatis-positive samples was amplified using a nested PCR based on ompA gene and then genotyped using a microsphere suspension array. RESULTS The overall prevalence of genital C trachomatis infection was 17.7%. The prevalence in patients at STD or GUM clinics was significantly higher than that in patients at OBGYN clinics. Being male (adjusted OR (AOR) 2.5, 95% CI 1.8 to 3.4), having no consistent use of a condom with casual partners in the past 3 months (AOR 1.7, 95% CI 1.1 to 2.8) and having any STD symptoms (AOR 3.3, 95% CI 2.0 to 5.4) were independently associated with C trachomatis infection. Eight genotypes were identified. The most prevalent genotypes were F (22.3%), E (22.0%) and D/Da (12.7%). Other genotypes were G/Ga (8.0%), J (7.3%), K (2.7%), H (2.7%) and I/Ia (0.4%). Eighty-two samples (18.3%) were infected with multiple genotypes. Genotype D/Da among patients from GUM clinics was more common than those from STD or OBGYN clinics. Infections with genotypes G and F were statistically associated with abnormal vaginal discharge (p=0.001) and being married (p=0.014), respectively. Infection with multiple genotypes was more common among patients with a higher income (p=0.011). CONCLUSION A substantial prevalence of genital C trachomatis infection in Shenzhen suggests the importance of detection and treatment of the infection in high-risk groups.