Chlamydia trachomatis serovar distributions in Russian men and women: a comparison with Dutch serovar distributions.

The data on serovar distributions of Chlamydia trachomatis - the most diagnosed sexually transmitted infection (STI) worldwide - are important for epidemiologic purposes and transmission studies but are completely lacking in Russia. The aim of the current study is to determine the serogroup and serovar distributions in Russian men and women and compare these data with Dutch serogroup and serovar distributions. In Russian men and women, serogroup B was the most prevalent (46%), followed by the intermediate serogroup (I group; 33%) and serogroup C (21%). The distribution was comparable between men and women. The serogroup distribution was similar to the previously published distribution in Dutch cohorts. However, on a serovar level statistically very significant differences were observed, reaching up to P < 0.0001. The serovars B and G/Ga had higher prevalences compared with the reported Dutch prevalences, while serovars F, H, I/Ia, J and K had lower prevalences compared with the Dutch studies. In conclusion, this is the first report of Russian C. trachomatis serovar/serogroup distributions. Serogroup B is the most prevalent, followed by serogroup I and serogroup C with no statistical differences on the serogroup level. However, significant differences between Russia and the Netherlands were observed in the distribution of C. trachomatis serovars.

TLR2 haplotypes in the susceptibility to and severity of Chlamydia trachomatis infections in Dutch women.

Chlamydia trachomatis infections may cause several disease conditions ranging from asymptomatic infections to severe upper genital tract pathology, thereby causing significant morbidity worldwide. Remarkable interindividual differences in the clinical course of C. trachomatis infection have been observed, and are mainly based on variation in genes encoding immune-regulatory and bacteria-sensing proteins. Toll-like receptors (TLRs) are closely involved in pathogen recognition and host defense in C. trachomatis infections. The aim of this study is to assess the role of TLR2 single nucleotide polymorphisms and haplotypes in the susceptibility to, and severity of C. trachomatis infections. The study comprised a sexually transmitted disease cohort of 468 Dutch Caucasian women and a control group of 321 women. The subfertility cohort consisted of 56 women with clinically well-defined tubal pathology. The results showed no significant differences in individual TLR2 genotype frequencies in the susceptibility for C. trachomatis infections between the C. trachomatis-positive group and controls. However, haplotype 1 was statistically significant (P = 0.015) and was associated with protection against tubal pathology following C. trachomatis infection. The same haplotype was also significantly decreased (P = 0.021) in increasing severity of C. trachomatis infections (asymptomatic > symptomatic > tubal pathology) suggesting a protective effect of this haplotype against the development of late complications.

Analyses of polymorphisms in the inflammasome-associated NLRP3 and miRNA-146A genes in the susceptibility to and tubal pathology of Chlamydia trachomatis infection.

Susceptibility to Chlamydia trachomatis infections is 40% host based. microRNA-146a is a negative regulator of Tolllike receptor (TLR) signaling and possesses functional polymorphisms which decrease the production of premiR-146a and mature miR-146a. Single nucleotide polymorphisms (SNPs) in NLRP3 are associated with decreased NLRP3 expression and hypoproduction of interleukin (IL)-1beta. We investigated whether the SNPs miR-146a G>C (rs2910164), NLRP3 C>T (rs4925663) and G>A (rs12065526) are associated with the susceptibility to and severity of C. trachomatis infection. The genotypes of three SNPs were tested in two cohorts: cohort 1 consists of Dutch women (n = 318) attending a sexually transmitted disease (STD) clinic and cohort 2 (n = 277) consists of subfertile (n = 184) and healthy Finnish women (n=93). While in cohort 1 the analyzed SNPs were not associated with the susceptibility to C. trachomatis infections (C. trachomatis-positive vs. C. trachomatis-negative), we showed in C. trachomatis-positive women that the NLRP3 mutant AG and AA genotypes were a risk factor for the development of symptoms (P = 0.047, OR = 2.9) and more specifically for having lower abdominal pain (genotype AA: P = 0.022, OR = 31.3). In the Finnish tubal pathology group versus the control group no statistical significant differences in the incidences of the SNPs studied were found, nor for the degree of tubal pathology. In conclusion, the mutant NLRP3 A allele is a risk factor for the development of symptoms, specifically lower abdominal pain, after a C. trachomatis infection in women attending an STD clinic.

Significantly higher serologic responses of Chlamydia trachomatis B group serovars versus C and I serogroups.

Chlamydia trachomatis serovars are divided into three serogroups, namely serogroup B, serogroup I (Intermediate) and serogroup C, and subsequently into 19 different serovars. Worldwide, serogroup B is the most prevalent followed by serogroup I. Clear differences have been observed in the duration of infection and growth kinetics between serovars from different serogroups in murine and cell culture models. Reasons for these observed differences are bacterial and host related, and are not well understood. The aim of this study was to determine the differences in immunoglobulin (Ig) G responses between the three serogroups in a group of patients infected with different serovars. Serovars were assessed from 235 C. trachomatispositive patients and quantitative IgG responses were determined. Analyses of variance were used to compare the IgG responses between the three serogroups. Of the serovars, 46% were B group (with serovar E the most prevalent: 35.3%), 39.6% were I group and 14.3% were C group. A highly significant difference in serologic response was shown when comparing the mean IgG concentrations (AU/mL) of patients having serovars in the most prevalent serogroup compared to the other serogroups: B = 135, C = 46 and I = 60 (B vs. C and B vs. I, P < 0.001). In conclusion, the most prevalent serovars generate the highest serologic responses.