Chlamydia trachomatis - the agent

Temporal and spatial differences in the vaginal microbiome of Chinese healthy women

Background

Up the reproductive tract, there are large differences in the composition of vaginal microbes. Throughout the menstrual cycle, the structure of the vaginal microbiome shifts. Few studies have examined both in combination. Our study was designed to explore trends in the microbiome of different parts of the vagina in healthy women over the menstrual cycle.

Methods

We performed metagenomic sequencing to characterize the microbiome differences between the cervical orifice and mid-vagina throughout the menstrual cycle.

Results

Our results showed the vaginal microbiome of healthy women in the cervical orifice and the mid-vagina was similar during the periovulatory and luteal phases, with Lactobacillus being the dominant bacteria. In the follicular phase, Acinetobacter was detected in the cervical orifice. From the follicular phase to the luteal phase, the community state types (all five community status types were defined as CSTs) in samples No. 10 and No. 11 changed from CST III to CST I. In addition, the composition of the vaginal microbiome in healthy women from different regions of China was significantly different. We also detected viruses including Human alphaherpesvirus 1 (HSV-1) during periovulatory phase.

Conclusion

This study is valuable for understanding whether the microbial composition of the vagina is consistent in different parts of the menstrual cycle.

Epigenetic changes induced by pathogenic Chlamydia spp

Chlamydia trachomatis, C. pneumoniae, and C. psittaci, the three Chlamydia species known to cause human disease, have been collectively linked to several pathologies, including conjunctivitis, trachoma, respiratory disease, acute and chronic urogenital infections and their complications, and psittacosis. In vitro, animal, and human studies also established additional correlations, such as between C. pneumoniae and atherosclerosis and between C. trachomatis and ovarian cancer. As part of their survival and pathogenesis strategies as obligate intracellular bacteria, Chlamydia spp. modulate all three major types of epigenetic changes, which include deoxyribonucleic acid (DNA) methylation, histone post-translational modifications, and microRNA-mediated gene silencing. Some of these epigenetic changes may be implicated in key aspects of pathogenesis, such as the ability of the Chlamydia spp. to induce epithelial-to-mesenchymal transition, interfere with DNA damage repair, suppress cholesterol efflux from infected macrophages, act as a co-factor in human papillomavirus (HPV)-mediated cervical cancer, prevent apoptosis, and preserve the integrity of mitochondrial networks in infected host cells. A better understanding of the individual and collective contribution of epigenetic changes to pathogenesis will enhance our knowledge about the biology of Chlamydia spp. and facilitate the development of novel therapies and biomarkers. Pathogenic Chlamydia spp. contribute to epigenetically-mediated gene expression changes in host cells by multiple mechanisms.

Chlamydia trachomatis infection in women living in remote areas in Amazonas, Brazil-a self-collection screening experience

Chlamydia trachomatis infection is the most common sexually transmitted bacterial infection among women. In Brazil, there is no organized screening program for C. trachomatis, and the actual prevalence of infection is unknown. This study aimed to determine the prevalence of C. trachomatis infection in women living in riverside communities in the Amazon, using self-collection employing the Evalyn® Brush and polymerase chain reaction. A total of 299 riverine women aged 18-81 years, mean age 35.7 (±12.8) years, predominantly agricultural workers, with low schooling and living with a partner, participated in this study. The prevalence of C. trachomatis infection was found to be 3.7% (95% CI 1.8-6.5), most of them being symptomatic. The mean age of the first sexual intercourse reported by women was 15.2 (±2.3) years, and the majority reported having had none or only one partner in the last 12 months, with very low adherence to consistent condom use (15.4%). Most women (98.3%) reported having approved using the vaginal self-collecting brush, and only 4.7% reported having difficulty in handling the brush. We consider that a vaginal self-collecting device is adequate for diagnosing C. trachomatis infection in women living in remote, hard-to-reach areas.

Characterization of Chlamydia trachomatis omp1 genotypes detected in eye swab samples from remote Australian communities

Chlamydia trachomatis conjunctival samples collected over a 6-month period from individuals with clinical signs of trachoma and located in remote communities in the Australian Northern Territory were differentially characterized according to serovar and variants. The rationale was to gain an understanding of the epidemiology of an apparent increased prevalence of acute trachoma in areas thought to be less conducive to this disease. Characterization was performed through sequencing of a region of the omp1 gene spanning the four variable domains and encoding the major outer membrane protein. Nucleotide and deduced amino acid sequences were genotyped by using a BLAST similarity search and were examined by phylogenetic analyses to illustrate evolutionary relationships between the clinical and GenBank reference strains. The predominant genotype identified corresponded to that of serovar C (87.1%), followed by the genotype corresponding to serovar Ba (12.9%). All nucleotide and amino acid sequences exhibited minor levels of variation with respect to GenBank reference sequences. The omp1 nucleotide sequences of the clinical samples best aligned with those of the conjunctival C. trachomatis reference strains C/TW-3/OT and Ba/Apache-2. All clinical samples (of serovar C) exhibited four or five nucleotide changes compared with C/TW-3/OT, while all serovar Ba samples had one or two nucleotide differences from Ba/Apache-2. Phylogenetic analyses revealed close relationships between these Northern Territory chlamydial samples and the respective reference strains, although the high proportion of sequence variants suggests an evolutionarily distinct C. trachomatis population causing eye infections in Australia. Given that such genotypic information has gone unreported, these findings provide knowledge and a foundation for trachoma-associated C. trachomatis variants circulating in the Northern Territory.