Prevalence of Chlamydia trachomatis Infection in Young Women and Associated Predictors

Sequence, structure prediction, and epitope analysis of the polymorphic membrane protein family in Chlamydia trachomatis

The polymorphic membrane proteins (Pmps) are a family of autotransporters that play an important role in infection, adhesion and immunity in Chlamydia trachomatis. Here we show that the characteristic GGA(I,L,V) and FxxN tetrapeptide repeats fit into a larger repeat sequence, which correspond to the coils of a large beta-helical domain in high quality structure predictions. Analysis of the protein using structure prediction algorithms provided novel insight to the chlamydial Pmp family of proteins. While the tetrapeptide motifs themselves are predicted to play a structural role in folding and close stacking of the beta-helical backbone of the passenger domain, we found many of the interesting features of Pmps are localized to the side loops jutting out from the beta helix including protease cleavage, host cell adhesion, and B-cell epitopes; while T-cell epitopes are predominantly found in the beta-helix itself. This analysis more accurately defines the Pmp family of Chlamydia and may better inform rational vaccine design and functional studies.

Antibody responses to Chlamydia trachomatis vaccine candidate antigens in Chlamydia-infected women and correlation with antibody-mediated phagocytosis of elementary bodies

Murine research has revealed a significant role for antibody responses in protection against Chlamydia reinfection. To explore potential humoral immune markers of protection elicited by Chlamydia trachomatis (CT) antigens in humans in the context of presumed clinical correlates of protection, we used both an IgG1-based ELISA and a conventional total IgG ELISA to evaluate antibody responses. We evaluated responses to five CT outer membrane proteins (PmpE, PmpF, PmpG, PmpH, and MOMP), along with other promising CT antigens (Pgp3 and HSP60), negative control antigens (RecO and AtpE), and CT elementary bodies (EBs) in sera from a well-characterized cohort of 60 women with different CT infection outcomes, including two outcomes that are likely clinical correlates of protective immunity: spontaneous resolution of infection and absence of reinfection after treatment. Furthermore, we used a flow cytometry-based assay to measure antibody-mediated phagocytosis by neutrophils in these sera. Results demonstrated that IgG1 ELISA displayed higher sensitivity than conventional total IgG ELISA in assessing antibody responses to CT EBs and antigens. Pgp3 IgG1 ELISA exhibited the highest sensitivity compared to IgG1 ELISA incorporating CT EBs or other antigens, confirming Pgp3 IgG1 ELISA as an ideal assay for CT antibody detection. Most (95%) sera from women with CT infection outcomes exhibited antibody-mediated phagocytosis of CT EBs, which was significantly correlated with IgG1 antibody responses to MOMP, Pgp3, HSP60, and PmpF. However, neither IgG1 responses to CT antigens and EBs nor antibody-mediated phagocytosis were associated with clinical correlates of protection. These findings suggest that neither CT IgG1 antibody detection nor antibody-mediated phagocytosis will be useful as immune correlates of protection against CT infection in humans.

Prevalence, risk factors and genotyping of chlamydia trachomatis from endocervical specimens of infertile women at a tertiary care hospital, Vietnam

BACKGROUND

To our knowledge, the prevalence, risk factors and distribution of C. trachomatis genotypes are rarely mentioned in Vietnam. This study aimed to find the prevalence, risk factors and distribution of C. trachomatis genotypes in infertile Vietnamese women.

METHODS

Endocervical swabs were collected from infertile women at the National Hospital of Obstetrics and Gynecology, Vietnam, between January 2020 and December 2021. All samples were analyzed for C. trachomatis presence by Cobas 4800 CT/NG Test. Sequencing methods of ompA gene were used to determine the C. trachomatis genotypes. An approximately 1200 bp ompA fragment was aligned with reference sequences from GenBank to identify the corresponding genotype.

RESULTS

The prevalence of endocervical C. trachomatis infection was 15.6% of 761 participants. Factors independently associated with CT infection among infertile women, obtained by multivariate analysis, included abnormal vaginal discharge, cervicitis, lower abdominal pain, a history of ectopic pregnancy, having more than one sex partner, and age at first intercourse. Among the samples, genotype E (25.93%) was most frequently found, followed by genotypes D/Da (22.23%), F (13.58%), G/Ga (12.35%), J (12.35%), H (6.17%), K (3.70%), B/Ba (2.47%), and I/Ia (1.23%), respectively. Genotype F was related to types of infertility, and genotype H was associated with a history of miscarriage.

CONCLUSIONS

The present study indicated a high prevalence of C. trachomatis in infertile Vietnamese women. The most common genotypes found in this population were E, D, and F. Our findings suggest that routine screening is necessary for early detection and performance of infection control methods.

Chlamydia trachomatis infection in Cuban adolescent and young populations

BACKGROUND

In Cuba, little is known regarding the prevalence of Chlamydia trachomatis (CT) infection in adolescents and young people. We study the frequency of CT infection in these populations, and its association with clinical-epidemiological variables.

METHODS

A total of 496 individuals aged 12 to 24 were recruited from November 2018 to November 2019. Of them, 302 were patients attending at sexually transmitted infections (STI) services and 194 were young volunteers. CT detections were carried out by real-time PCR and IgG serology.

RESULTS

The prevalence of CT using PCR was 9.1% (45/496); 12.3% (37/302) for subjects attending STI service and 4.1% (8/194) for young volunteers, being significantly higher in the first group (OR=3.25; p=.001). CT IgG antibodies was detected in 38.6% (81/210). Individuals from 12 to 17 years old were more likely infected with CT (OR=2.21; p=.010). Infection was associated with the early onset of sexual intercourse, the frequent changing of sexual partners and black ethnicity.

CONCLUSIONS

The results suggest that Cuban adolescents and young populations are at highest risk of acquiring CT infection and developing reproductive complications. The data obtained advise the needs of implementation of a routine CT screening strategy, for timely diagnosis, detection and treatment at the earliest ages.

Seroprevalence of Chlamydia trachomatis and Associated Factors among Vulnerable Riverine in the Brazilian Amazon

Due to social and individual conditions and access to health services, Amazonian riverside populations are highly vulnerable to sexually transmitted infections, including Chlamydia trachomatis. The aim is to estimate the seroprevalence of Chlamydia trachomatis and analyze the associated factors among riverside dwellers in a capital city in the Brazilian Amazon. A cross-sectional study was carried out with residents of the Combu Island, Belém. The study sample was calculated using the population survey technique in the EPI INFO. Only people aged 18 and over were included. ELISA serology was performed to detect antibodies against Chlamydia trachomatis. For data collection, a form containing vulnerability factor questions was applied. Binary regression analysis was performed using the Minitab 20 program. The study sample consisted of 325 participants. The prevalence of IgG/IgM antibodies against Chlamydia trachomatis was 22.2% and 5.5%, respectively. In the multiple regression, only participants with a broken condom were more likely to have antibodies against the bacteria (OR: 1.90; 95% CI: 1.01; 3.37; p = 0.046). Seroprevalence was associated with condom breakage. This factor demonstrates that despite having an attitude towards condom use, probably, they may have inadequate knowledge about the correct practice of introduction.

New insights into Chlamydia pathogenesis: Role of leukemia inhibitory factor

Chlamydia trachomatis (Ct) is the leading cause of bacterial sexually transmitted infections worldwide. Since the symptoms of Ct infection are often subtle or absent, most people are unaware of their infection until they are tested or develop severe complications such as infertility. It is believed that the primary culprit of Ct-associated tissue damage is unresolved chronic inflammation, resulting in aberrant production of cytokines, chemokines, and growth factors, as well as dysregulated tissue influx of innate and adaptive immune cells. A member of the IL-6 cytokine family, leukemia inhibitory factor (LIF), is one of the cytokines induced by Ct infection but its role in Ct pathogenesis is unclear. In this article, we review the biology of LIF and LIF receptor (LIFR)-mediated signaling pathways, summarize the physiological role of LIF in the reproductive system, and discuss the impact of LIF in chronic inflammatory conditions and its implication in Ct pathogenesis. Under normal circumstances, LIF is produced to maintain epithelial homeostasis and tissue repair, including the aftermath of Ct infection. However, LIF/LIFR-mediated signaling – particularly prolonged strong signaling – can gradually transform the microenvironment of the fallopian tube by altering the fate of epithelial cells and the cellular composition of epithelium. This harmful transformation of epithelium may be a key process that leads to an enhanced risk of infertility, ectopic pregnancy and cancer following Ct infection.

Chlamydia trachomatis Infection and Seropositivity in Women Reporting Sexual Contact to a Chlamydia-Infected Partner

ABSTRACT

Among 73 women presenting to a sexually transmitted infection (STI) clinic in Birmingham, Alabama for reported sexual contact to a chlamydia-infected partner, Chlamydia trachomatis was detected in genital specimens in 24 (32.8%), less often in women reporting prior chlamydial infection ( P = 0.001). Most women (93.2%) were C. trachomatis seropositive.