Molecular And Seroepidemiological Characteristics Among Female Genital Chlamydia Trachomatis Infection

Objective:Chlamydia trachomatis(C.trachomatis)is the most common bacterial sexually transmitted pathogen in the world.This study was to clarify the molecular,seroepidemiological and clinical characteristics of female reproductive tract C.trachomatis infection,providing reference basis for the effective control of C.trachomatis infection.Methods:A total of 8261 cervical samples and 743 serum samples were collected from female aged 16-70 during July 2019 to June 2021 in Chenzhou NO.1 People’s Hospital.Nested PCR combined with sequencing technology was used for C.trachomatis genotyping;DNAStar and MEGA7 software were used to compare and analyze the mutation sites of C.trachomatis omp1 VS1-VS2 fragment and the correlation degree and evolutionary distance between C.trachomatis DNA positive sample sequences;C.trachomatis pgp3 antibody was detected by luciferase immunosorbent assay(LISA);Routine leucorrhea,colposcopy and cervical cytology data were collecte.To analyzed their relation to C.trachomatis molecule and serum epidemiological characteristics.Result:1.The overall infection rate of C.trachomatis in female reproductive tract was 3.74%(309/8261),4.76%(165/3468)in gynecological group,3.36%(62/1843)in infertility women and 2.78%(82/2950)in physical examination women.There was significance in C.trachomatis infection rates among the three groups(P<0.05),while there was no significant difference in C.trachomatis infection rates between infertile women and physical examination women(P>0.05);Age was the risk factor of Ct infection(OR=0.951,95%CI:0.939-0.963,P<0.001);2.The abnormal level of leucorrhea cleanliness[63.13%(125/198)vs 33.97%(283/833),P<0.001]and the incidence of CIN[15.05%(14/93)vs 3.09%(36/1166),P<0.001]in C.trachomatis DNA positive patients were higher than those in C.trachomatis DNA negative patients;3.Among 309 C.trachomatis DNA positive samples,9 C.trachomatis genotypes(B,Da,D,E,F,G,H,J and K)were detected.The three most common genotypes were E[1.03%(85/8261)],F[0.87%(72/8261)],J[0.73%(60/8261)].The phylogenetic tree showed that the homology between F and G and between H,K,and J was high,and the homology between F and E was low;4.The overall mutation rate of C.trachomatis ompl VS1-VS2 was 27.30%(83/304).The mutation rate of genotypes J was 100%(59/59),and there was no mutation of genotypes B;5.There was no significant difference in inflammation[32.08%(17/53)vs 28.10%(43/153),P>0.05]and the incidence of CIN[15.09%(8/53)vs 7.19%(11/153),P>0.05]between patients with mutation of C.trachomatis omp1 VS1-VS2 fragment and patients without mutation.Colposcopy showed that the incidence of CIN in patients with C.trachomatis ornp1 VS1-VS2 meaningful mutation[40%(4/10)vs 8%(2/25),P<0.05]was higher than that in patients with nonsense mutation,while cervical cytology showed that there was no significant difference in the incidence of CIN between patients with C.trachomatis omp1 VS1-VS2 meaningful mutation and patients with nonsense mutation[21.05%(4/19)vs 11.76%(4/34),P>0.05];6.The total positive rate of C.trachomatis pgp3 antibody was 47.46%(355/748)in the asymptomatic infected population.The positive rate of pgp3 antibody in C.trachomatis DNA positive group was significantly higher than that in C.trachomatis DNA negative group[90%(45/50)vs 44.41%(310/698),P<0.05];There was no significant difference in the positive rate of pgp3 antibody between physical examination group and infertility group[86.67%(26/30)vs 95%(19/20),P>0.05];In the C.trachomatis DNA negative population,the infertility group was significantly higher than the physical examination group[56.74%(261/460)vs 20.59%(49/238),P<0.001].7.There was no significant difference between C.trachomatis pgp3 antibody positive and negative patients in the incidence of CIN[1.14%(3/263)vs 3.31%(6/181),P>0.05].Conclusion:1.In this study the overall infection rate of C.trachomatis among female reproductive tract is relatively high.The incidence of CIN and abnormal leucorrhea cleanliness in C.trachomatis DNA positive population were higher than those in C.trachomatis DNA negative population.Age is the risk factor of C.trachomatis infection,suggesting that it is necessary to strengthen the screening of C.trachomatis reproductive tract infection in young women;2.There was no significant difference in the positive rate of C.trachomatis DNA between infertile women and physical examination women,but the positive rate of C.trachomatis pgp3 in infertile population is significantly higher than that in physical examination population,suggesting that a large proportion of C.trachomatis infection occurred among female infertile indivduals was previous infection.