Serological investigation of the role of selected sexually transmitted infections in the aetiology of ectopic pregnancy

Establishment and performance evaluation of multiplex PCR-dipstick DNA chromatography assay for simultaneous diagnosis of four sexually transmitted pathogens

INTRODUCTION

Rapid, sensitive, and specific diagnostic methods are indispensable for sexually transmitted infections (STIs). In this study, a multiplex PCR-dipstick DNA chromatography assay for diagnosis of four STI pathogens, namely Neisseria gonorrhoeae (N. gonorrhoeae), Mycoplasma hominis (M. hominis), Ureaplasma (U. urealyticum and U. parvum), and Chlamydia trachomatis (C. trachomatis), was established and evaluated.

METHODS

Based on the hybridization of probes and interaction between streptavidin and biotin, PCR products were visualized through hybridization of specific probes and enzymatic color generation. The sensitivity and specificity of all four pathogens were evaluated. Clinical performance of the test was evaluated using 295 specimens, and comparisons among results were determined via culture or colloidal gold assay.

RESULTS

No cross-reactions were observed, confirming the high specificity of this method. The limit of detection (LOD) of the four STI pathogens was 100 copies/μL. The sensitivity between PCR-dipstick DNA chromatography and culture or colloidal gold assay ranged from 84.6% to 100%. The specificity was between 93.5% and 96.6%, positive predictive value ranged from 53.6% to 86.7%, negative predictive value was over 98.3%, kappa value ranged from 0.676 to 0.864 (Cohen's kappa coefficient test), and the agreement rate was over 93.5%.

CONCLUSION

In conclusion, PCR-dipstick DNA chromatography serves as a rapid, sensitive, and specific method for simultaneous diagnosis of four STI pathogens.

Relation of Chlamydia trachomatis infections to ectopic pregnancy: A meta-analysis and systematic review

BACKGROUND

In a multitude of previous studies, Chlamydia trachomatis (CT) plays an important role in the occurrence of ectopic pregnancy (EP). However, the predictive value of CT infections in the occurrence of EP has not been estimated worldwide. We thus evaluated, by means of a meta-analysis, the current status of the association between CT infections with EP and the potential predictive value of CT infections in EP.

METHODS

We evaluated studies performed between the database construction time and August 2018 published in PubMed, the Cochrane Library, EMBASE, and the Web of Science (SCI). The relationship between CT and EP was calculated based upon the predetermined entry criteria for control group selection and the original data. The related articles were analyzed using a random-effects model, and the heterogeneity of the studies was assessed using the I index. Data were analyzed with the STATA 12.0 software.

RESULTS

Twenty-five studies that recruited 11960 patients were included in the present meta-analysis, and the relation of CT infections with EP were assessed. The association between CT infections and EP risk showed an odds ratio (OR) of 3.03, with a 95% confidence interval (CI) of 2.37 to 3.89. Our results showed that there was a statistically significant difference between the intervention and control groups. The prevalence of CT infections in EP was then calculated by a subgroup analysis: African (OR, 2.22; 95% CI, 1.14-4.31), European (OR, 3.16; 95% CI, 2.10-4.47), North American (OR, 3.07; 95% CI, 1.78-5.31), and Asian (OR, 3.39; 95% CI, 1.95-5.90).

CONCLUSIONS

From the results of numerous studies conducted on different continents, this meta-analysis showed a clear association between EP and prior CT infections, that is, CT infections increase the risk of EP occurrence.

Chlamydia trachomatis and mycoplasma infections in tubal pregnancy

Chlamydia trachomatis (CT) infection is an important factor for tubal pregnancy. However, whether Ureaplasma urealyticum (UU) and Mycoplasma hominis (MH) infections are also involved in tubal pregnancy remains unknown. This study is aimed to detect CT, UU, and MH in cervical secretions from patients with tubal pregnancy and control women in early pregnancy, to explore their prevalence rates and drug susceptibilities. Analysis was performed on patients with tubal pregnancy and those requiring termination of early pregnancy at <12 weeks from July 2013 to March 2014. Cervical secretions were tested for UU/MH with a UU/MH isolation and culture kit and for CT antigen by an immunochromatographic assay. Mycoplasma samples were tested for resistance to 12 antibiotics. There were no cases of CT infection detected. Mycoplasma infection rates (single or mixed) were similar in the tubal pregnancy and control groups, but the total rate of infection was higher for tubal pregnancy. All MH samples were sensitive to tetracyclines as well as josamycin and azithromycin. Josamycin and clarithromycin were effective against all UU cultures. Over 50% of the samples tested were resistant to ciprofloxacin.

Simultaneous detection of eleven sexually transmitted agents using multiplexed PCR coupled with MALDI-TOF analysis

Purpose

Sexually transmitted infections (STIs), representing a major global health problem, are caused by different microbes, including bacteria, viruses, and protozoa. Unfortunately, infections of different sexually transmitted pathogens often present similar clinical symptoms, so it is almost impossible to distinguish them clinically. Therefore, the aim of the current study was to develop a sensitive, multitarget, and high-throughput method that can detect various agents responsible for STIs.

Methods

We developed and tested a 23-plex PCR coupled with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) assay (sexually transmitted infection-mass spectrometry, STI-MS) that simultaneously targets 11 different agents, including 8 most common clinical pathogens related to STIs (HSV-1, HSV-2, Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, Trichomonas vaginalis, Mycoplasma genitalium, and Haemophilus ducreyi) and 3 controversial microorganisms as pathogens (Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum).

Results

The results showed that the STI-MS approach can accurately detect the expected agents, without cross-reaction with other organisms. The limit of detection of each STI-MS assay was ranged from 1.739 to 10.009 copies/reaction, using probit analyses. The verification rate for each target organism of the STI-MS ranged from a minimum of 89.3% to a maximum of 100%, using conventional assays and ultrasensitive digital PCR to confirm the STI-MS-positive results. To further evaluate the clinical performance of this assay, 241 clinical specimens (124 urethral/cervical swabs and 117 urine) were tested in parallel using the STI-MS assay and monoplex real-time PCR for each agent. The overall validation parameters of STI-MS were extremely high including sensitivity (from 85.7% to 100%), specificity (from 92.3% to 100%), PPV (from 50% to 100%), and NPV (from 99.1% to 100%) for each target.

Conclusion

STI-MS is a useful high-throughput screening tool for detecting mixed infections of STIs and has great potential for application in large-scale epidemiological programs for specific microorganisms of STI.

Ectopic pregnancy following oral levonorgestrel emergency contraception use

Levonorgestrel is used worldwide as an emergency oral contraceptive. There have been occasional reports of ectopic pregnancy after oral levonorgestrel use. We present a case of ectopic tubal pregnancy after the use of oral levonorgestrel as an emergency contraceptive in a 37-year-old woman with a history of treatment for Chlamydia trachomatis infection. She conceived after sexual intercourse on menstrual day 14 of the first menstrual cycle following a normal delivery. After salpingectomy for this right tubal pregnancy, her following pregnancy was an ectopic pregnancy in the contralateral tube, which was treated with laparoscopic salpingectomy. Histopathological examination revealed endometriosis. We should be aware of ectopic pregnancy even after emergency contraceptive use, especially in patients with risk factors, such as Chlamydia infection and endometriosis. Because the efficacy of levonorgestrel decreases after ovulation, we should check the stage of the cycle before prescription.

Blood Cadmium Concentrations in Women with Ectopic Pregnancy

The purpose of this study is to investigate the relationship between the blood level of cadmium and the occurrence of ectopic pregnancy. Forty-one (41) case patients with ectopic pregnancy and 41 uncomplicated intrauterine pregnant patients as controls were recruited. The concentrations of cadmium (Cd) were measured from blood samples using atomic absorption spectrometry. The cases and controls were similar in age, body mass index, and smoking habits. The median blood level of Cd was 0.32 μg/l (interquartile range [IQR] 0.00-0.71) in the women with ectopic pregnancies and 0.34 μg/l (IQR 0.09-0.59) in the controls. There was no significant association between blood cadmium levels and ectopic pregnancy.

Systemic antibody response to Chlamydia Trachomatis infection in patients either infected or reinfected with different Chlamydia serovars

INTRODUCTION

Chlamydia trachomatis is the etiological agent for the most prevalent bacterial sexually transmitted infection in both developed and developing countries. The aim of present study was to characterize the antibody response between two groups of individuals, having either a single C. trachomatis infection and or repeated infections.

MATERIAL AND METHODS

Current study consisted of two groups, one with an initial Chlamydia infection and a second with repeated infections. A titre based estimation of specific serum (IgG and IgA) levels using ELISA were performed, which further validated by western blot. In vitro neutralizing ability of each patient's serum against both homologous and heterologous strains was also determined.

RESULTS

Individuals infected with one of the C. trachomatis serovars D, E or K exhibited a strong systemic antibody response as characterized by ELISA and western blot. These individuals may have developed at least some level of protection as they only represented single infection. By comparison, individuals infected with serovar D, E or F that exhibited low systemic antibody response often presented repeated C. trachomatis infections, suggesting an association with poor immune response. An in vitro neutralizing level of 60-90% was observed in the human sera against homologous serovar D and two heterologous C. trachomatis serovars E and K, compared to <40% against heterologous serovars F.

CONCLUSION

Individuals infected with serovars D and K showed a potential association between circulating antibody response and re-infection risk. While the patients infected with serovars E showed a disconnection between systemic antibody response and re-infection risk.

Prevalence of Curable Sexually Transmitted Infections in Pregnant Women in Low- and Middle-Income Countries From 2010 to 2015: A Systematic Review

BACKGROUND

Current literature comparing the prevalence rates of curable sexually transmitted infections (STIs) in pregnant women in various global regions is limited. As a result, antenatal screening practices for curable STIs in pregnant women, specifically Treponema pallidum (syphilis), Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), and Trichomonas vaginalis (TV) vary around the world, differing by country and particular STI.

METHODS

We conducted a systematic review of publications on STI prevalence among pregnant women in 30 different low- and middle-income countries. We searched PubMed for studies reporting prevalence of syphilis, CT, NG, and TV in pregnant women. English language studies published between January 1, 2010, and March 1, 2015, were included. The adjusted mean STI prevalence by region was calculated via multivariable linear regression adjusting for health care setting, women's mean age, study sample size, and sensitivity of diagnostic test.

RESULTS

We identified 75 studies that met inclusion criteria, providing 116 point prevalence estimates for curable STIs among 3,489,621 pregnant women. Adjusted mean prevalence for NG ranged from 1.2% (95% confidence interval [CI], 1.0-1.3) in Latin America to 4.6% (95% CI, 4.0-5.2) in Southern Africa; syphilis prevalence ranged from 1.1% (95% CI, 0.5-1.6) in Asia to 6.5% (95% CI, 4.7-6.3) in Southern Africa; CT ranged from 0.8% (95% CI, 0.4-1.1) in Asia to 11.2% (95% CI, 6.0-16.4) in Latin America; and TV ranged from 3.9% (95% CI, 2.2-5.6) in Latin America to 24.6% (95% CI, 17.9-31.4) in Southern Africa.

CONCLUSIONS

Although we observed a wide variation in STI burden in pregnancy after adjusting for age, test, and health care setting, further valid comparison may depend on adjustment for access to care and screening practices.

Patients with cervical Ureaplasma Urealyticum and Chlamydia Trachomatis infection undergoing IVF/ICSI-ET: The need for new paradigm

Genital tract infections with ureaplasma urealyticum (UU) and chlamydia trachomatis (CT) are the most frequent sexually-transmitted disease worldwide. UU and CT infections are considered to be the leading cause for infertility and adverse pregnancy outcomes. However, little is known about the specific effect of cervical UU and CT infections on the etiology of female infertility, as well as the pregnancy outcomes of the patients undergoing in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET). In order to find the association between cervical UU and/or CT infection and pregnancy outcomes, we conducted a retrospective case-control study on the patients undergoing IVF/ICSI-ET with cervical UU and/or CT infection. A total of 2208 patients who received IVF/ICSI-ET were enrolled in this study. Data on the general conditions, pregnancy history and clinical pregnant outcomes were analyzed in terms of the cervical UU and CT detection. Our results revealed that cervical UU and CT infections were the risk factors for ectopic pregnancy and tubal factor-induced infertility. Moreover, the pregnancy rate, abortion rate, ectopic pregnancy rate and premature birth rate in patients with UU and/or CT infections showed no significant difference when compared with the control group. We recommend that cervical UU and CT detection should be an optional item for infertility patients and clinical UU detection should differentiate the subtypes of cervical UU. Positive cervical UU and CT infections should not be taken as strict contraindications for IVF/ICSI-ET.

Danger signals, inflammasomes, and the intricate intracellular lives of chlamydiae

Chlamydiae are obligate intracellular bacterial pathogens, and as such are sensitive to alterations in the cellular physiology of their hosts. Chlamydial infections often cause pathologic consequences due to prolonged localized inflammation. Considerable advances have been made in the last few years regarding our understanding of how two key inflammation-associated signaling pathways influence the biology of Chlamydia infections: inflammation regulating purinergic signaling pathways significantly impact intracellular chlamydial development, and inflammasome activation modulates both chlamydial growth and infection mediated pro-inflammatory cytokine production. We review here elements of both pathways, presenting the latest developments contributing to our understanding of how chlamydial infections are influenced by inflammasomes and purinergic signaling.

Genital Chlamydia trachomatis: understanding the roles of innate and adaptive immunity in vaccine research

Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide, and despite significant advances in chlamydial research, a prophylactic vaccine has yet to be developed. This Gram-negative obligate intracellular bacterium, which often causes asymptomatic infection, may cause pelvic inflammatory disease (PID), ectopic pregnancies, scarring of the fallopian tubes, miscarriage, and infertility when left untreated. In the genital tract, Chlamydia trachomatis infects primarily epithelial cells and requires Th1 immunity for optimal clearance. This review first focuses on the immune cells important in a chlamydial infection. Second, we summarize the research and challenges associated with developing a chlamydial vaccine that elicits a protective Th1-mediated immune response without inducing adverse immunopathologies.

Chlamydia trachomatis Infection in Pregnancy: The Global Challenge of Preventing Adverse Pregnancy and Infant Outcomes in Sub-Saharan Africa and Asia

Screening and treatment of sexually transmitted infections (STIs) in pregnancy represents an overlooked opportunity to improve the health outcomes of women and infants worldwide. Although Chlamydia trachomatis is the most common treatable bacterial STI, few countries have routine pregnancy screening and treatment programs. We reviewed the current literature surrounding Chlamydia trachomatis in pregnancy, particularly focusing on countries in sub-Saharan Africa and Asia. We discuss possible chlamydial adverse pregnancy and infant health outcomes (miscarriage, stillbirth, ectopic pregnancy, preterm birth, neonatal conjunctivitis, neonatal pneumonia, and other potential effects including HIV perinatal transmission) and review studies of chlamydial screening and treatment in pregnancy, while simultaneously highlighting research from resource-limited countries in sub-Saharan Africa and Asia.

Chlamydial polymorphic membrane proteins: regulation, function and potential vaccine candidates

Pmps (Polymorphic Membrane Proteins) are a group of membrane bound surface exposed chlamydial proteins that have been characterized as autotransporter adhesins and are important in the initial phase of chlamydial infection. These proteins all contain conserved GGA (I, L, V) and FxxN tetrapeptide motifs in the N-terminal portion of each protein. All chlamydial species express Pmps. Even in the chlamydia-related bacteria Waddlia chondrophila, a Pmp-like adhesin has been identified, demonstrating the importance of Pmps in Chlamydiales biology. Chlamydial species vary in the number of pmp genes and their differentially regulated expression during the infectious cycle or in response to stress. Studies have also demonstrated that Pmps are able to induce innate immune functional responses in infected cells, including production of IL-8, IL-6 and MCP-1, by activating the transcription factor NF-κB. Human serum studies have indicated that although anti-Pmp specific antibodies are produced in response to a chlamydial infection, the response is variable depending on the Pmp protein. In C. trachomatis, PmpB, PmpC, PmpD and PmpI were the proteins eliciting the strongest immune response among adolescents with and without pelvic inflammatory disease (PID). In contrast, PmpA and PmpE elicited the weakest antibody response. Interestingly, there seems to be a gender bias for Pmp recognition with a stronger anti-Pmp reactivity in male patients. Furthermore, anti-PmpA antibodies might contribute to adverse pregnancy outcomes, at least among women with PID. In vitro studies indicated that dendritic cells infected with C. muridarum were able to present PmpG and PmpF on their MHC class II receptors and T cells were able to recognize the MHC class-II bound peptides. In addition, vaccination with PmpEFGH and Major Outer Membrane Protein (MOMP) significantly protected mice against a genital tract C. muridarum infection, suggesting that Pmps may be an important component of a multi-subunit chlamydial vaccine. Thus, Pmps might be important not only for the pathogenesis of chlamydial infection, but also as potential candidate vaccine proteins.

The Role of the Immune Response in Chlamydia trachomatis Infection of the Male Genital Tract: A Double-Edged Sword

Chlamydia trachomatis (CT) is the most prevalent bacterial sexually transmitted infection in the world, with more than 100 million cases reported annually. While there have been extensive studies into the adverse effects that CT infection has on the female genital tract, and on the subsequent ability of these women to conceive, studies into the consequences on male fertility have been limited and controversial. This is in part due to the asymptomatic nature of the infection, where it is estimated that 50% of men with Chlamydia fail to show any symptoms. It is accepted, however, that acute and/or persistent CT infection is the causative agent for conditions such as urethritis, epididymitis, epididymo-orchitis, and potentially prostatitis. As with most infections, the immune system plays a fundamental role in the body’s attempts to eradicate the infection. The first and most important immune response to Chlamydia infection is a local one, whereby immune cells such as leukocytes are recruited to the site of infections, and subsequently secrete pro-inflammatory cytokines and chemokines such as interferon gamma. Immune cells also work to initiate and potentiate chronic inflammation through the production of reactive oxygen species (ROS), and the release of molecules with degradative properties including defensins, elastase, collagenase, cathespins, and lysozyme. This long-term inflammation can lead to cell proliferation (a possible precursor to cancer), tissue remodeling, and scarring, as well as being linked to the onset of autoimmune responses in genetically disposed individuals. This review will focus on the ability of the immune system to recognize and clear acute and persistent chlamydial infections in the male genital tract, and on the paradoxical damage that chronic inflammation resulting from the infection can cause on the reproductive health of the individual.