Prevalence and distribution of Chlamydia trachomatis genovars in Indian infertile patients: a pilot study

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.

Evaluation of Chlamydia trachomatis Genotypes in Endocervical Specimens by Sequence Analysis of ompA Gene among Women in Tehran

Tehran's actual prevalence of Chlamydia trachomatis (CT) and its genotypes are still unclear. Molecular typing of CT strains can provide essential epidemiological knowledge and contribute to improved control measures. In this study, we aimed to determine the prevalence of CT and its genotypes in the endocervical infections of females who attended the gynecology and infertility clinics in Tehran. A total of 291 women were tested for chlamydial infection by in-house PCR using specific primers for the CT cryptic plasmid. Nested PCR for amplification of the ompA gene in positive samples was carried out, genotyping was performed by sequencing this gene, and further phylogenetic analysis was conducted. Sexual infection by CT was observed in 10.3% (30/291) of the subjects, and the mean age of patients was 30.4. The ompA gene was sequenced in 27 samples, revealing E genotypes 40.7%, (n = 11), F 25.9%, (n = 7), G 18.5%, (n = 5), D 11.1%, (n = 3), and K 3.7%, (n = 1). This study emphasizes the importance of the diversity among CT genotypes in our studied population and the need for wide-screening the neglected bacterial infection among women in Tehran.

Genetic and clinical characteristics of genital Chlamydia trachomatis infection in Guangzhou, China

BACKGROUND

Genital Chlamydia trachomatis (CT) is one of the most common agents of sexually transmitted infections and can cause severe disorders. This study aimed to analyse the genetic and clinical characteristics of genital CT infection among women in Guangzhou, China.

METHODS

From September 2020 to August 2021, a total of 8955 female patients were enrolled in this study. The presence of genital CT was detected by real-time PCR, and 273 positive samples were randomly selected for further genetic and clinical characteristics analysis.

RESULTS

The positive rate of genital CT infection was 7.5% (670/8955), with the highest rate in women aged 21-30 years. A total of 8 genotypes were identified: DH, J, K, and recombinant genotype Ba/D. The predominant genotype was J (n = 78, 28.6%), followed by E (n = 63, 23.1%), F (n = 48, 17.6%), and D (n = 38, 13.9%). Abnormal vaginal discharge (n = 165, 61.8%), cervical columnar epithelial ectopy (n = 124, 46.4%), vaginal itching (n = 77, 28.8%), and lower abdominal pain (n = 61, 22.8%) were the predominant symptoms. Additionally, genotype G infection exhibited a significantly higher rate of abnormal vaginal discharge (P = 0.03) and genotype D infection exhibited a higher white blood cell count (P = 0.01) than the other genotypes. Phylogenetic analysis revealed a total of 20 variants with 25 mutation positions and the H2 variant in four patients was first discovered in our study.

CONCLUSIONS

Genotypes J, E, F, and D were the major genotypes of genital CT in Guangzhou, and they manifested as abnormal vaginal discharge, cervical columnar epithelial ectopy, vaginal itching, and lower abdominal pain. The present study provides guidance for future integrated interventions to reduce the burden of genital CT infection and accelerate the development of vaccines.

The Correlation between Chlamydia Trachomatis and Female Infertility: A Systematic Review

The impact of Chlamydia trachomatis (CT) infection on female's fertility is not completely established yet, since the level of evidence associating these factors is still weak. Hence, the goal of the present review is to contribute to a better elucidation of this matter. The electronic database chosen was the Medline/PubMed, with the last survey on May 11, 2021. Publication date was used as a filter, with the previous 5 years having been selected. The following describers were used: chlamydia trachomatis AND infertility; chlamydia trachomatis AND tubal alteration AND infertility; chlamydia AND low pregnancy rates. From the 322 studies screened, 293 that failed to meet our eligibility criteria were excluded. Subsequently, we removed seven studies for not having the possible correlation between CT infections and female infertility as its main focus, and three for being about sexually transmitted infections (STIs) in general. Moreover, two studies designed as reviews were also excluded. Ergo, we included 17 studies in our qualitative analysis. The authors conducted research individually and analyzed carefully the studies selected. As we retrieved the information needed for our study through reading the texts, no contact was made with the authors of the studies selected. This systematic review corroborates the hypothesis that CT infection potentiates female infertility, as 76.47% of the included studies found a positive correlation between them. We conclude that there is an important association between CT infection and female infertility. Ergo, making CT screening part of the infertility investigation routine is relevant and has a reasonable justification.

Diagnosis of Chlamydia trachomatis genital infections in the era of genomic medicine

PURPOSE

Chlamydial genital infections constitute significant sexually transmitted infections worldwide. The often asymptomatic status of C. trachomatis (CT) infections leads to an increased burden on human reproductive health, especially in middle- and low-income settings. Early detection and management of these infections could play a decisive role in controlling this public health burden. The objective of this review is to provide an insight into the evolution of diagnostic methods for CT infections through the development of new molecular technologies, emphasizing on -omics' technologies and their significance as diagnostic tools both for effective patient management and control of disease transmission.

METHODS

Narrative review of the diagnostic methodologies of CT infections and the impact of the introduction of -omics' technologies on their diagnosis by review of the literature.

RESULTS

Various methodologies are discussed with respect to working principles, required specifications, advantages, and disadvantages. Implementing the most accurate methods in diagnosis is highlighted as the cornerstone in managing CT infections.

CONCLUSION

Diagnostics based on -omics' technologies are considered to be the most pertinent modalities in CT testing when compared to other available methods. There is a need to modify these effective and accurate diagnostic tools in order to render them more available and feasible in all settings, especially aiming on turning them to rapid point-of-care tests for effective patient management and disease control.

High-resolution multilocus sequence typing for Chlamydia trachomatis: improved results for clinical samples with low amounts of C. trachomatis DNA

Background

Several Multilocus Sequence Typing (MLST) schemes have been developed for Chlamydia trachomatis. Bom’s MLST scheme for MLST is based on nested PCR amplification and sequencing of five hypervariable genes and ompA. In contrast to other Chlamydia MLST schemes, Bom’s MLST scheme gives higher resolution and phylogenetic trees that are comparable to those from whole genome sequencing. However, poor results have been obtained with Bom’s MLST scheme in clinical samples with low concentrations of Chlamydia DNA.

Results

In this work, we present an improved version of the scheme that is based on the same genes and MLST database as Bom’s MLST scheme, but with newly designed primers for nested-1 and nested-2 steps under stringent conditions. Furthermore, we introduce a third primer set for the sequencing step, which considerably improves the performance of the assay. The improved primers were tested in-silico using a dataset of 141 Whole Genome Sequences (WGS) and in a comparative analysis of 32 clinical samples. Based on cycle threshold and melting curve analysis values obtained during Real-Time PCR of nested-1 & 2 steps, we developed a simple scoring scheme and flow chart that allow identification of reaction inhibitors as well as to predict with high accuracy amplification success. The improved MLST version was used to obtain a genovars distribution in patients attending an STI clinic in Tel Aviv.

Conclusions

The newly developed MLST version showed great improvement of assay results for samples with very low concentrations of Chlamydia DNA. A similar concept could be applicable to other MLST schemes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-020-02077-y.

Mycoplasma hominis: An under recognized pathogen

Mycoplasma hominis, a commensal of the genital tract, is a potential underestimated pathogen causing both genitourinary and extragenital infections including neonatal infections. Septic arthritis, prosthetic joint infection, central nervous system (CNS) infections, infective endocarditis and abscess formation are common extragenital infections associated mainly with immunocompromised patients. Mycoplasma hominis lipoproteins play an important role in pathogenicity and directly interact with the host immune system. Polymerase chain reaction (PCR) is the mainstay of diagnosis. Increasing resistance to tetracyclines and quinolones which are used for treatment, is a matter of global concern. We reviewed PubMed literature and Google search engine on the recent developments of association of Mycoplasma hominis with various diseases, pathogenesis, diagnosis and treatment.

Prevalence, concordance and reproductive sequelae after Chlamydia trachomatis infection in Mexican infertile couples

There are few concordance studies on the Chlamydia trachomatis (infection among infertile couples. The objective of this research was to know the prevalence, concordance and reproductive sequelae that couples may develop when both partners show a C. trachomatis infection. A cross-sectional study among 688 infertile couples using the C. trachomatis detection by real-time PCR was performed. The infertility causes were obtained from their medical records. The prevalence of infection was 8.68%. The percentage of concordance was 22.4% (13 couples). A presence of tubal occlusion was only associated with infected-discordant women [RR = 3.46, 95% CI (1.54-7.74), p < .003]. Seminal values were not associated with discordant men. The concordant couples showed association with the infection and tubal occlusion [RR = 3.19, 95% CI (1.09-9.34), p < .05], and oligozoospermia [RR = 12.17, 95% CI (4.29-34.54), p < .001], hypospermia [RR = 14.13, 95% CI (4.78-41.84), p < .001]. An alteration in semen quality was shown particularly in men whose sexual partners show a tubal pathology. This could occur due to a C. trachomatis infection in the testis, which underlines the need to carry out effective and efficient strategies to identify and treat all sexual partners exposed to C. trachomatis.

Distribution of Chlamydia trachomatis omp A genotypes in patients attending a sexually transmitted disease outpatient clinic in New Delhi, India

Background & objectives:

Limited data are available on the typing of Chlamydia trachomatis in India. Serovars D to K of C. trachomatis are chiefly responsible for urogenital infections. Thus, this study was conducted to determine the distribution of C. trachomatis serovars in patients with urogenital infections and to characterize ompA gene of the detected C. trachomatis isolates by sequence analysis. Presence of other co-infections was also evaluated.

Methods:

Endocervical swabs were collected from 324 women and urethral swabs/urine were collected from 193 men attending the sexually transmitted diseases outpatient clinic. The samples were screened for C. trachomatis by cryptic plasmid PCR and ompA gene PCR. Genotyping was performed by PCR-restriction fragment length polymorphism (RFLP) and sequencing of the ompA gene. Samples were screened for genital mycoplasmas, Neisseria gonorrhoeae, Treponema pallidum and human immunodeficiency virus (HIV).

Results:

C. trachomatis was found in 15.0 per cent men and 10.8 per cent women. Serovar D was the most prevalent followed by serovars E, F, I and G. Twenty two C. trachomatis isolates were selected for ompA gene sequencing. No mixed infection was found. Variability in ompA sequences was seen in 31.8 per cent cases. Both PCR-RFLP and ompA gene sequencing showed concordant results. The presence of Ureaplasma spp. and Mycoplasma hominis was observed in 18.7 and 9.5 per cent patients, respectively. Co-infection of C. trachomatis was significantly associated with Ureaplasma urealyticum and HIV.

Interpretation & conclusions:

The high occurence of C. trachomatis infections warrants its screening in addition to other sexually transmitted infections namely U. urealyticum and HIV. Genotyping of the ompA gene may provide additional information for vaccine development.

Prevalence and Genotype Distribution of Chlamydia trachomatis in Urine among Men Attending Sexually Transmitted Disease Clinics in Guangdong Province, China, in 2016

Studies have rarely assessed the genotype distribution of Chlamydia trachomatis (CT) in urine among men attending sexually transmitted disease clinics (MSCs) in China. This study was aimed at investigating the prevalence and molecular epidemiology of CT infection by examining urine samples among MSCs from different geographic areas of Guangdong Province, China. A cross-sectional study was conducted among MSCs from 10 human immunodeficiency virus sentinel surveillance sites in Guangdong Province. CT DNA was extracted from male urine samples and analyzed using a Roche cobas 4800 CT/NG. The ompA genes were amplified by nested PCR and sequenced. The leukocyte esterase test was performed by routine urine analysis at local clinics. Of the 1,903 samples, 163 (8.6%, 95% confidence interval [CI] 3.8-16.3%) tested positive for CT. The highest prevalence (10.5%) of CT infection was observed among participants aged between 21 and 30 years. A total of 130 CT-positive samples (79.8%, 130/163) were successfully genotyped by nested PCR, resulting in 8 genotypes. The most prevalent genotypes were D, E, F, and J, with proportions of 20.8%, 20.0%, 17.7%, and 16.9%, respectively. There were no significant correlations between the geographical areas, leukocyte esterase test results and genotype distribution. Promotion of detection and molecular epidemiology research is needed for effective and comprehensive prevention and control programs.

The impact of Chlamydia trachomatis infection on sperm parameters and male fertility: A comprehensive study

Chlamydia trachomatis (CT), an obligate intracellular bacterium, requires living cells to replicate. Half of men infected with CT are asymptomatic. CT infection can persist for up to four years within couples and affect their fertility. Chlamydia infection in men acts as a reservoir for transmission to women and can cause urinary tract inflammation, sperm DNA damage, and acute epididymitis. Semen samples from 1080 subfertile patients with normal and abnormal spermograms were examined to detect the presence of CT. An ELISA test was used to detect the presence of anti-CT IgA in these patients' seminal plasma. CT infection was also confirmed by molecular investigation using specific primers. In order to evaluate the effect of CT infections on the DNA Fragmentation Index (DFI), 40 CT-infected cases and 20 CT-negative controls were analyzed by a Sperm Chromatin Structure Assay using flow cytometry. Among 1080 patients with poor sperm parameters, 155 (14.3%) patients were diagnosed with CT, 11% among those with semen abnormalities and 26% among those without semen abnormalities patients. The DFI was statistically higher in cases than in controls (p < 0.05). Given the prevalence of infection and also the high frequency of asymptomatic CT infection among infertile individuals with poor sperm parameters, screening for infection in these patients is essential in order to avoid adverse sequelae. We propose that the higher rate of DFI in CT-infected infertile men might be an underlying cause of their infertility and this warrants greater attention.

Molecular typing of Chlamydia trachomatis: An overview

Urogenital infection due to Chlamydia trachomatis (CT) is one of the most common bacterial sexually transmitted infections (STIs) and is a major public health problem worldwide. Molecular characterisation of CT is important for understanding the pathophysiological mechanisms of chlamydial disease and its transmission dynamics in sexual networks. Traditionally, strain typing of CT was based on serotyping methods characterising the major outer membrane protein (MOMP). With the advent of polymerase chain reaction and sequencing the era of molecular typing began. Molecular characterization of CT strains is based on sequence analysis of ompA gene encoding MOMP. However, in due course of time, improvements were made to enhance the discriminatory power of sequencing and quality of epidemiological information. New high-resolution genotyping methods using multiple loci such as multilocus sequence typing (MLST) and multiple loci variable number of tandem repeats (MLVA) were developed but were unable to differentiate mixed infections (MIs). The development of DNA-hybridisation methods emerged as a major breakthrough in detecting MIs. Although MLST and MLVA are more discriminative than other genotyping methods, they are laborious and expensive. DNA microarray technique is an affordable alternative for genotyping. Since recombination is widespread in the CT genome, ompA is not a reliable marker for phylogenetic studies; hence, whole genome sequencing may provide maximum phylogenetic resolution of CT strains. A descriptive review is provided of the various molecular CT typing methods. The vital information gained can be used for formulating screening programmes, targeted prevention and optimising therapeutic measures aiming to reduce disease transmission.