Chlamydia trachomatis: the Persistent Pathogen

Integrating lncRNAs and mRNAs Expression Profiles in Penicillin-Induced Persistent Chlamydial Infection in HeLa Cells

Chlamydia trachomatis (C. trachomatis) is a major etiological agent of sexually transmitted infection. Some stressing conditions can result in persistent chlamydial infection, which is thought to be associated with severe complications including ectopic pregnancy and tubal factor infertility. Long noncoding RNAs (lncRNAs) have been identified as key modulators in many biological processes. Nevertheless, the role of lncRNAs in persistent chlamydial infection is still unclear. In this study, we used lncRNA and mRNA microarray to identify the global lncRNAs and mRNAs expression in penicillin-induced persistent chlamydial infection in HeLa cells as well as the control group (HeLa cells without C. trachomatis infection). Among 1005 differentially expressed lncRNAs, 585 lncRNAs were upregulated and 420 downregulated in persistent chlamydial infection, while 410 mRNAs were identified to express differentially, of which 113 mRNAs were upregulated and 297 downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis with differentially expressed genes were performed. We then constructed the lncRNA-miRNA-mRNA competing endogenous RNAs (ceRNAs) network. Four mRNAs were validated to be changed by quantitative real-time PCR which were correlated with the microarray result. Integration of protein-protein interaction network was constructed and hub genes were identified. These findings provide a new perspective on the molecular mechanisms of penicillin-induced persistent chlamydial infection.

Bridging the gap between development of point-of-care nucleic acid testing and patient care for sexually transmitted infections

The incidence rates of sexually transmitted infections (STIs), including the four major curable STIs - chlamydia, gonorrhea, trichomoniasis and, syphilis - continue to increase globally, causing medical cost burden and morbidity especially in low and middle-income countries (LMIC). There have seen significant advances in diagnostic testing, but commercial antigen-based point-of-care tests (POCTs) are often insufficiently sensitive and specific, while near-point-of-care (POC) instruments that can perform sensitive and specific nucleic acid amplification tests (NAATs) are technically complex and expensive, especially for LMIC. Thus, there remains a critical need for NAAT-based STI POCTs that can improve diagnosis and curb the ongoing epidemic. Unfortunately, the development of such POCTs has been challenging due to the gap between researchers developing new technologies and healthcare providers using these technologies. This review aims to bridge this gap. We first present a short introduction of the four major STIs, followed by a discussion on the current landscape of commercial near-POC instruments for the detection of these STIs. We present relevant research toward addressing the gaps in developing NAAT-based STI POCT technologies and supplement this discussion with technologies for HIV and other infectious diseases, which may be adapted for STIs. Additionally, as case studies, we highlight the developmental trajectory of two different POCT technologies, including one approved by the United States Food and Drug Administration (FDA). Finally, we offer our perspectives on future development of NAAT-based STI POCT technologies.

YAP1 induces marrow derived suppressor cell recruitment in Chlamydia trachomatis infection

Chlamydia trachomatis (C. trachomatis) is the most commonly diagnosed bacterial sexually transmitted infection (STI) worldwide. Marrow derived suppressor cells (MDSCs) are a heterogeneous population of immature monocytes and granulocytes, which are effective inhibitors for T cell activation. This study explores the role of MDSCs in the immune escape mechanism of C. trachomatis. We established a vaginal infection model of a BALB/c-Chlamydia trachomatis mouse pneumonia strain (MoPn), and compared the percentages of MDSCs, CD4⁺T, and CD8⁺T cells in the spleen and cervix of mice before and after infection. The expression levels of arginase-1 (Arg-1) and inducible nitric oxide synthase (iNOS) in MDSCs, and the expression level of transcriptional co-activator yes-associated protein 1 (YAP1) in the cervix were also compared. The results show that the proportion of MDSCs increases, while the proportion of CD4⁺T and CD8⁺T cells decreases after C. trachomatis-infection. The expression of Arg-1 and iNOS in MDSCs and YAP1 in host cells is up-regulated. C. trachomatis growth is inhibited after the inhibition of YAP1 in host cells. The proportion of MDSCs decreases after in vivo pharmacological inhibition of YAP1 in the C. trachomatis-infected mouse model. These results demonstrate, for the first time, the participation of MDSC in the immune escape of C. trachomatis under the action of YAP1.

Lipid larceny: channelizing host lipids for establishing successful pathogenesis by bacteria

Lipids are complex organic compounds made up of carbon, oxygen, and hydrogen. These play a diverse and intricate role in cellular processes like membrane trafficking, protein sorting, signal transduction, and bacterial infections. Both Gram-positive bacteria (Staphylococcus sp., Listeria monocytogenes, etc.) and Gram-negative bacteria (Chlamydia sp., Salmonella sp., E. coli, etc.) can hijack the various host-lipids and utilize them structurally as well as functionally to mount a successful infection. The pathogens can deploy with various arsenals to exploit host membrane lipids and lipid-associated receptors as an attachment for toxins' landing or facilitate their entry into the host cellular niche. Bacterial species like Mycobacterium sp. can also modulate the host lipid metabolism to fetch its carbon source from the host. The sequential conversion of host membrane lipids into arachidonic acid and prostaglandin E2 due to increased activity of cPLA-2 and COX-2 upon bacterial infection creates immunosuppressive conditions and facilitates the intracellular growth and proliferation of bacteria. However, lipids' more debatable role is that they can also be a blessing in disguise. Certain host-lipids, especially sphingolipids, have been shown to play a crucial antibacterial role and help the host in combating the infections. This review shed light on the detailed role of host lipids in bacterial infections and the current understanding of the lipid in therapeutics. We have also discussed potential prospects and the need of the hour to help us cope in this race against deadly pathogens and their rapidly evolving stealthy virulence strategies.

Host-Pathogen Interactions of Chlamydia trachomatis in Porcine Oviduct Epithelial Cells

Chlamydia trachomatis (Ct) causes the most prevalent bacterial sexually transmitted disease leading to ectopic pregnancy and infertility. Swine not only have many similarities to humans, but they are also susceptible to Ct. Despite these benefits and the ease of access to primary tissue from this food animal, in vitro research in swine has been underutilized. This study will provide basic understanding of the Ct host–pathogen interactions in porcine oviduct epithelial cells (pOECs)—the counterparts of human Fallopian tube epithelial cells. Using NanoString technology, flow cytometry, and confocal and transmission-electron microscopy, we studied the Ct developmental cycle in pOECs, the cellular immune response, and the expression and location of the tight junction protein claudin-4. We show that Ct productively completes its developmental cycle in pOECs and induces an immune response to Ct similar to human cells: Ct mainly induced the upregulation of interferon regulated genes and T-cell attracting chemokines. Furthermore, Ct infection induced an accumulation of claudin-4 in the Ct inclusion with a coinciding reduction of membrane-bound claudin-4. Downstream effects of the reduced membrane-bound claudin-4 expression could potentially include a reduction in tight-junction expression, impaired epithelial barrier function as well as increased susceptibility to co-infections. Thereby, this study justifies the investigation of the effect of Ct on tight junctions and the mucosal epithelial barrier function. Taken together, this study demonstrates that primary pOECs represent an excellent in vitro model for research into Ct pathogenesis, cell biology and immunity.

Bioinspired drug delivery strategies for repurposing conventional antibiotics against intracellular infections

Bacteria have developed a wealth of strategies to avoid and resist the action of antibiotics, one of which involves pathogens invading and forming reservoirs within host cells. Due to the poor cell membrane permeability, stability and retention of conventional antibiotics, this renders current treatments largely ineffective, since achieving a therapeutically relevant antibiotic concentration at the site of intracellular infection is not possible. To overcome such challenges, current antibiotics are 'repurposed' via reformulation using micro- or nano-carrier systems that effectively encapsulate and deliver therapeutics across cellular membranes of infected cells. Bioinspired materials that imitate the uptake of biological particulates and release antibiotics in response to natural stimuli are recently explored to improve the targeting and specificity of this 'nanoantibiotic' approach. In this review, the mechanisms of internalization and survival of intracellular bacteria are elucidated, effectively accentuating the current treatment challenges for intracellular infections and the implications for repurposing conventional antibiotics. Key case studies of nanoantibiotics that have drawn inspiration from natural biological particles and cellular uptake pathways to effectively eradicate intracellular pathogens are detailed, clearly highlighting the rational for harnessing bioinspired drug delivery strategies.

Pelvic inflammatory disease in the adolescent and young adult: An update

Pelvic inflammatory disease (PID) is an infection of the female upper genital tract that is typically polymicrobial with classic core involvement of Neisseria gonorrhoeae and/or Chlamydia trachomatis, though other endogenous flora from the vagino-cervical areas can be involved as well. It is often a sexually transmitted disease but other etiologic routes are also noted. A variety of risk factors have been identified including adolescence, young adulthood, adolescent cervical ectropion, multiple sexual partners, immature immune system, history of previous PID, risky contraceptive practices and others. An early diagnosis and prompt treatment are necessary to reduce risks of PID complications such as chronic pelvic pain, ectopic pregnancy and infertility. Current management principles of PID are also reviewed. It is important for clinicians to screen sexually active females for common sexually transmitted infections such as Chlamydia trachomatis and provide safer sex education to their adolescent and young adult patients. Clinicians should provide comprehensive management to persons with PID and utilize established guidelines such as those from the US Centers for Disease Control and Prevention (CDC).

Alterations of Vaginal Microbiota in Women With Infertility and Chlamydia trachomatis Infection

Chlamydia trachomatis (C. trachomatis) is the most common etiological agent of bacterial sexually transmitted infections (STIs) worldwide and causes serious health sequelae such as cervicitis, pelvic inflammatory disease, and even infertility if ascending from the lower to the upper female genital tract. Previous studies have revealed the pivotal role of vaginal microbiota in susceptibility to STIs. However, alterations in the vaginal microbiota in women who are infertile and infected with C. trachomatis remain unknown. This study used metagenomic analysis of sequenced 16S rRNA gene amplicons to examine the vaginal microbial profiles of women with tubal infertility who were C. trachomatis-negative and those who were C. trachomatis-positive pre- and post-antibiotic treatment. Women who were C. trachomatis-negative and deemed healthy were recruited as references of eubiosis and dysbiosis. Women with tubal infertility and C. trachomatis infection presented a unique Lactobacillus iners-dominated vaginal microbiota rather than one dominated by Lactobacillus crispatus and displayed a decrease in Lactobacillus, Bifidobacterium, Enterobacter, Atopobium, and Streptococcus, accompanied by decreased levels of cytokines such as interferon (IFN)-γ and interleukin (IL)-10. This altered vaginal microbiota could be restored with varying degrees after standard treatment for C. trachomatis. This shift could be a predictive vaginal microbiota signature for C. trachomatis infection among females with tubal infertility, while no significant differences in phylum, class, and operational taxonomic unit (OTU) levels were observed between women with tubal infertility who were C. trachomatis-negative and healthy controls. This is the first study to provide data on the association of vaginal microbiota with C. trachomatis infection among women with tubal infertility and highlights unprecedented potential opportunities to predict C. trachomatis infection.

Inhibition of Chlamydial Infection by CRISPR/Cas9-SAM Mediated Enhancement of Human Peptidoglycan Recognition Proteins Gene Expression in HeLa Cells

The global problem of emerging resistance of microorganisms to antibiotics makes the search for new natural substances with antibacterial properties relevant. Such substances include peptidoglycan recognition proteins (PGLYRP), which are the components of the innate immunity of many organisms, including humans. These proteins have a unique mechanism of action that allows them to evade the resistance of bacteria to them, as well as to be active against both Gram-positive and Gram-negative bacteria. However, the use of antimicrobial recombinant proteins is not always advisable due to the complexity of local delivery of the proteins and their stability; in this regard it seems appropriate to activate the components of the innate immunity. The aim of this study was to increase the expression level of native peptidoglycan recognition protein genes in HeLa cells using genome-editing technology with synergistic activation mediators (CRISPR/Cas9-SAM) and evaluate antichlamydial effect of PGLYRP. We demonstrated activation of the chlamydial two-component gene system (ctcB-ctcC), which played a key role in the mechanism of action of the peptidoglycan recognition proteins. We generated the HeLa cell line transduced with lentiviruses encoding CRISPR/Cas9-SAM activation system with increased PGLYRP gene expression. It was shown that activation of the own peptidoglycan recognition proteins gene expression in the cell line caused inhibition of the chlamydial infection development. The proposed approach makes it possible to use the capabilities of innate immunity to combat infectious diseases caused by Gram-positive and Gram-negative bacteria.

Chlamydia Trachomatis Infection: Their potential implication in the Etiology of Cervical Cancer

Pathogenic bacterial strains can alter the normal function of cells and induce different levels of inflammatory responses that are connected to the development of different diseases, such as tuberculosis, diarrhea, cancer etc. Chlamydia trachomatis (C. trachomatis) is an intracellular obligate gram-negative bacterium which has been connected with the cervical cancer etiology. Nevertheless, establishment of causality and the underlying mechanisms of carcinogenesis of cervical cancer associated with C. trachomatis remain unclear. Studies reveal the existence of C. trachomatis in cervical cancer patients. The DNA repair pathways including mismatch repair, nucleotide excision, and base excision are vital in the abatement of accumulated mutations that can direct to the process of carcinogenesis. C. trachomatis recruits DDR proteins away from sites of DNA damage and, in this way, impedes the DDR. Therefore, by disturbing host cell-cycle control, chromatin and DDR repair, C. trachomatis makes a situation favorable for malignant transformation. Inflammation originated due to infection directs over production of reactive oxygen species (ROS) and consequent oxidative DNA damage. This review may aid our current understanding of the etiology of cervical cancer in C. trachomatis-infected patients.

Akt Phosphorylation Influences Persistent Chlamydial Infection and Chlamydia-Induced Golgi Fragmentation Without Involving Rab14

Chlamydia trachomatis is an obligate intracellular bacterium that causes multiple diseases involving the eyes, gastrointestinal tract, and genitourinary system. Previous studies have identified that in acute chlamydial infection, C. trachomatis requires Akt pathway phosphorylation and Rab14-positive vesicles to transmit essential lipids from the Golgi apparatus in survival and replication. However, the roles that Akt phosphorylation and Rab14 play in persistent chlamydial infection remain unclear. Here, we discovered that the level of Akt phosphorylation was lower in persistent chlamydial infection, and positively correlated with the effect of activating the development of Chlamydia but did not change the infectivity and 16s rRNA gene expression. Rab14 was found to exert a limited effect on persistent infection. Akt phosphorylation might regulate Chlamydia development and Chlamydia-induced Golgi fragmentation in persistent infection without involving Rab14. Our results provide a new insight regarding the potential of synergistic repressive effects of an Akt inhibitor with antibiotics in the treatment of persistent chlamydial infection induced by penicillin.

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.

Presence of Chlamydia trachomatis DNA in the amniotic fluid in women with preterm prelabor rupture of membranes

OBJECTIVE

The primary aim of this study was to assess the rate and load of amniotic fluid Chlamydia trachomatis DNA and their associations with intra-amniotic infection and intra-uterine inflammatory complications in women with preterm prelabor rupture of membranes (PPROM). The secondary aim was to assess the short-term morbidity of newborns from PPROM pregnancies complicated by amniotic fluid C. trachomatis DNA.

METHODS

A retrospective study of 788 women with singleton pregnancies complicated by PPROM between 24 + 0 and 36 + 6 weeks of gestation was performed. Transabdominal amniocenteses were performed at the time of admission. C. trachomatis DNA in the amniotic fluid was assessed by real-time polymerase chain reaction using a commercial AmpliSens® C. trachomatis/Ureaplasma/Mycoplasma hominis-FRT kit, and the level of Ct DNA was quantified.

RESULTS

Amniotic fluid C. trachomatis DNA complicated 2% (16/788) of the PPROM pregnancies and was present in very low loads (median 57 copies DNA/mL). In addition to amniotic fluid C. trachomatis DNA, other bacteria were detected in 62% (10/16) of the C. trachomatis DNA-complicated PPROM pregnancies. Amniotic fluid C. trachomatis DNA was associated with intra-amniotic infection, histologic chorioamnionitis (HCA), and funisitis in 31%, 47%, and 33%, respectively. The presence of C. trachomatis DNA accompanied by Ureaplasma species in the amniotic fluid was associated with a higher rate of HCA than the presence of amniotic fluid C. trachomatis DNA alone. The composite neonatal morbidity in newborns from PPROM pregnancies with amniotic fluid C. trachomatis DNA was 31%.

CONCLUSION

The presence of C. trachomatis DNA in the amniotic fluid is a relatively rare condition in PPROM. Amniotic fluid C. trachomatis DNA in PPROM is not related to intensive intra-amniotic and intr-auterine inflammatory responses or adverse short-term neonatal outcomes.

Genital Tract Infection during Pregnancy and its Association with Preterm Delivery

Genital tract infection (GTI) remains a significant health concern. It is estimated that in 2016, there were 370 million people who suffer from chlamydia, gonorrhea, and trichomoniasis; and 708 million others suffer from genital herpes and condyloma acuminatum. It has been reported that in pregnant women, GTI is associated with preterm delivery. The mechanisms of GTI-associated preterm delivery need to be further understood to prevent neonatal mortality and morbidity that could be the risk factor for neonates’ growth and development disorders. This article aims to describe various types of GTI and the associated pathogenesis causing preterm birth. A literature search was conducted to retrieve recent articles published in English from online databases including Pubmed, ScienceDirect, and Google Scholar. This literature study found that GTI evokes inflammatory responses that trigger several mechanisms leading to preterm delivery. The inflammatory responses in GTI include the production of proinflammatory cytokines and robust activation of neutrophils. The key mechanisms that stimulate preterm delivery in GTI include the events of early uterine contraction, preterm premature rupture of membranes, and induction of cervical ripening; which are under normal circumstances in a full-term pregnancy, those mechanisms are regulated by progesterone and prostaglandin levels along with suppression of the inflammatory responses. In conclusion, this paper has described the underlying mechanisms of preterm delivery in pregnant women with ISG. However, such mechanisms remain unclear in candida and gonococcal infection; thus, prompting the need for further studies. 

Identification of differentially expressed genes and signaling pathways in human conjunctiva and reproductive tract infected with Chlamydia trachomatis

Background

Currently, Chlamydia trachomatis–specific host defense mechanisms in humans remain poorly defined. To study the characteristics of host cells infected early with Chlamydia trachomatis, we used bioinformatics methods to analyze the RNA transcription profiles of the conjunctiva, fallopian tubes, and endometrium in humans infected with Chlamydia trachomatis.

Method

The gene expression profiles of GSE20430, GSE20436, GSE26692, and GSE41075 were downloaded from the Gene Expression Synthesis (GEO) database. Then, we obtained the differentially expressed genes (DEGs) through the R 4.0.1 software. STRING was used to construct protein–protein interaction (PPI) networks; then, the Cytoscape 3.7.2 software was used to visualize the PPI and screen hub genes. GraphPad Prism 8.0 software was used to verify the expression of the hub gene. In addition, the gene–miRNA interaction was constructed on the NetworkAnalyst 3.0 platform using the miRTarBase v8.0 database.

Results

A total of 600 and 135 DEGs were screened out in the conjunctival infection group and the reproductive tract infection group, respectively. After constructing a PPI network and verifying the hub genes, CSF2, CD40, and CSF3 in the reproductive tract infection group proved to have considerable statistical significance.

Conclusion

In our research, the key genes in the biological process of reproductive tract infection with Chlamydia trachomatis were clarified through bioinformatics analysis. These hub genes may be further used in clinical treatment and clinical diagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40246-021-00313-8.

Chlamydia trachomatis: Cell biology, immunology and vaccination

Chlamydia trachomatis is the causative agent of a highly prevalent sexually transmitted bacterial disease and is associated with a number of severe disease complications. Current therapy options are successful at treating disease, but patients are left without protective immunity and do not benefit the majority asymptomatic patients who do not seek treatment. As such, there is a clear need for a broad acting, protective vaccine that can prevent transmission and protect against symptomatic disease presentation. There are three key elements that underlie successful vaccine development: 1) Chlamydia biology and immune-evasion adaptations, 2) the correlates of protection that prevent disease in natural and experimental infection, 3) reflection upon the evidence provided by previous vaccine attempts. In this review, we give an overview of the unique intra-cellular biology of C. trachomatis and give insight into the dynamic combination of adaptations that allow Chlamydia to subvert host immunity and survive within the cell. We explore the current understanding of chlamydial immunity in animal models and in humans and characterise the key immune correlates of protection against infection. We discuss in detail the specific immune interactions involved in protection, with relevance placed on the CD4+ T lymphocyte and B lymphocyte responses that are key to pathogen clearance. Finally, we provide a timeline of C. trachomatis vaccine research to date and evaluate the successes and failures in development so far. With insight from these three key elements of research, we suggest potential solutions for chlamydial vaccine development and promising avenues for further exploration.

[Prevalence and Risk Factors of Chlamydia Trachomatis Infection Among Women Consulting at the Sexually Transmitted Infection Centre in la Reunion: A Cross-Sectional Study]

Introduction

Chlamydia trachomatis (CT) infection is the commonest bacterial sexually transmitted infection (STI) in the world. Often asymptomatic, it can lead to significant complications in women. In France, since 2003, systematic screening for CT in STI center has been recommended for women aged less than 25 year. The main objective of this study was to determine CT prevalence in patients attending STI centers in Reunion Island. The second objective was to explore the determinants of this infection.

Method

A cross-sectional survey using an anonymous questionnaire was conducted among women attending STI center in two hospitals in western and southern Reunion Island during one year. All women who had performed a CT PCR, based on vaginal self-swabs, were included.

Results

Among the 620 patients tested, the prevalence of infection was 6.6% (95% CI [4.7-8.6]). By age group, the highest prevalence was between 12 and 17 years with 14.3% positive tests compared to 7.5% and 3.9% respectively in 18-24 and 25-67 year age group (p = 0.003). The risk factors for CT were a young age (p = 0.02), a first sexual intercourse between 11 and 14 years old (p = 0.01), lack of previous STI screening history (p = 0.02), and the following motives for seeking screening: "partner unfaithfulness" (p = 0.01) and "infected partner" (p = 0.02).

Conclusion

This study highlights the high prevalence of CT among Reunionese minors. A more systematic screening and a reinforcement of STI awareness among young people in Reunion Island seem to be essential.

Eutopic endometrium from women with endometriosis and chlamydial endometritis share immunological cell types and DNA repair imbalance: A transcriptome meta-analytical perspective

The aim of this study was to identify the key similarities between the eutopic endometrium of women with endometriosis and chlamydia-induced endometritis taking into account tissue microenvironment heterogeneity, transcript gene profile, and enriched pathways. A meta-analysis of whole transcriptome microarrays was performed using publicly available data, including samples containing both glandular and stromal endometrial components. Control samples were obtained from women without any reported pathological condition. Only samples obtained during the proliferative menstrual phase were included. Cellular tissue heterogeneity was predicted using a method that integrates gene set enrichment and deconvolution approaches. The batch effect was estimated by principal variant component analysis and removed using an empirical Bayes method. Differentially expressed genes were identified using an adjusted p-value < 0.05 and fold change = 1.5. The protein-protein interaction network was built using the STRING database and interaction score over 400. The Molecular Signatures Database was used to analyse the functional enrichment analysis. Both conditions showed similarities in cell types in the microenvironment, particularly CD4⁺ and CD8⁺ Tem cells, NKT cells, Th2 cells, basophils, and eosinophils. With regards to the regulation of cellular senescence and DNA integrity/damage checkpoint, which are commonly enriched pathways, 21 genes were down-regulated and directly related to DNA repair. Compared to the endometriosis samples, some chlamydial endometritis samples presented a lack of enriched immune pathways. Our results suggest that both conditions show similar distributions of microenvironment cell types, the downregulation of genes involved in DNA repair and cell cycle control, and pathways involved in immune response evasion.

Chlamydial clinical isolates show subtle differences in persistence phenotypes and growth in vitro

Urogenital Chlamydia trachomatis infection is the most common sexually transmitted bacterial infection throughout the world. While progress has been made to better understand how type strains develop and respond to environmental stress in vitro, very few studies have examined how clinical isolates behave under similar conditions. Here, we examined the development and persistence phenotypes of several clinical isolates, to determine how similar they are to each other, and the type strain C. trachomatis D/UW-3/Cx. The type strain was shown to produce infectious progeny at a higher magnitude than each of the clinical isolates, in each of the six tested cell lines. All chlamydial strains produced the highest number of infectious progeny at 44 h post-infection in the McCoy B murine fibroblast cell line, yet showed higher levels of infectivity in the MCF-7 human epithelial cell line. The clinical isolates were shown to be more susceptible than the type strain to the effects of penicillin and iron deprivation persistence models in the MCF-7 cell line. While subtle differences between clinical isolates were observed throughout the experiments conducted, no significant differences were identified. This study reinforces the importance of examining clinical isolates when trying to relate in vitro data to clinical outcomes, as well as the importance of considering the adaptations many type strains have to being cultured in vitro.

Chlamydia trachomatis induces autophagy by p62 in HeLa cell

Chlamydia trachomatis is the most common bacterial pathogen causing sexually transmitted diseases. C. trachomatis infection is closely related to the development of cervical cancer, studies have shown that C. trachomatis can induce host cell autophagy. The autophagy related gene p62 plays an important role in the process of autophagy. To further understand the role of autophagy-associated gene p62 in autophagy of HeLa cells induced by C. trachomatis, p62-silencing cell line, HeLa229-shp62, and control cell line, HeLa229-shNC, were constructed, and a C. trachomatis-infected cell model was established. The autophagosome and C. trachomatis inclusions were observed under electron microscope. The autophagy level of C. trachomatis-infected HeLa cells was detected by Western blot. The results suggested that knockdown of p62 affected neither C. trachomatis infection of HeLa cells nor the initiation of C. trachomatis-induced autophagy, but at 48 h post C. trachomatis infection, autophagy levels were significantly inhibited in p62 silencing host cells. The study demonstrated the important role of p62 in the autophagy induced by C. trachomatis in HeLa cells, which could provide data support and theoretical basis for exploring the pathogenesis and prevention of C. trachomatis.

Generation of a novel affibody molecule targeting Chlamydia trachomatis MOMP

Abstract

Chlamydia trachomatis (C. trachomatis) is the leading cause of preventable blindness worldwide and the most prevalent cause of bacterial sexually transmitted diseases. At present, there is no available vaccine, and recurrences after antibiotics treatment are substantial problems. Major outer membrane protein (MOMP) accounts for 60% of the outer mass of C. trachomatis, functioning as trimeric porin, and it is highly antigenic. Therefore, MOMP is the most promising candidate for vaccine developing and target therapy of Chlamydia. Affibody, a new class of affinity ligands derived from the Z-domain in the binding region of Staphylococcus aureus protein A, has been the focus of researchers as a viable alternative to antibodies. In this study, the MOMP-targeted affibody molecule (Z_MOMP:461) was screened by phage-displayed peptide library. Further, the affinity and specificity were characterized by surface plasmon resonance (SPR) and Western blot. Immunofluorescence assay (IFA) indicated that the MOMP-binding affibody could recognize native MOMP in HeLa229 cells infected C. trachomatis. Immunoprecipitation assay confirmed further that Z_MOMP:461 molecule specifically recognizes the epitope on relaxed trimer MOMP. Our findings provide strong evidence that affibody molecule (Z_MOMP:461) serves as substitute for MOMP antibody for biological applications and has a great potential for delivering drugs for target therapy.

Key points

• We screened a novel affibody molecule Z_MOMP:461 targeting Chlamydia trachomatis MOMP.

• Z_MOMP:461 recognizes the recombinant and native MOMP with high affinity and specificity.

• Z_MOMP:461 could be internalized into live target cells.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-021-11128-x.

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.

Persistence of Intracellular Bacterial Pathogens-With a Focus on the Metabolic Perspective

Persistence has evolved as a potent survival strategy to overcome adverse environmental conditions. This capability is common to almost all bacteria, including all human bacterial pathogens and likely connected to chronic infections caused by some of these pathogens. Although the majority of a bacterial cell population will be killed by the particular stressors, like antibiotics, oxygen and nitrogen radicals, nutrient starvation and others, a varying subpopulation (termed persisters) will withstand the stress situation and will be able to revive once the stress is removed. Several factors and pathways have been identified in the past that apparently favor the formation of persistence, such as various toxin/antitoxin modules or stringent response together with the alarmone (p)ppGpp. However, persistence can occur stochastically in few cells even of stress-free bacterial populations. Growth of these cells could then be induced by the stress conditions. In this review, we focus on the persister formation of human intracellular bacterial pathogens, some of which belong to the most successful persister producers but lack some or even all of the assumed persistence-triggering factors and pathways. We propose a mechanism for the persister formation of these bacterial pathogens which is based on their specific intracellular bipartite metabolism. We postulate that this mode of metabolism ultimately leads, under certain starvation conditions, to the stalling of DNA replication initiation which may be causative for the persister state.

State-of-the-art polymeric nanoparticles as promising therapeutic tools against human bacterial infections

Infectious diseases kill over 17 million people a year, among which bacterial infections stand out. From all the bacterial infections, tuberculosis, diarrhoea, meningitis, pneumonia, sexual transmission diseases and nosocomial infections are the most severe bacterial infections, which affect millions of people worldwide. Moreover, the indiscriminate use of antibiotic drugs in the last decades has triggered an increasing multiple resistance towards these drugs, which represent a serious global socioeconomic and public health risk. It is estimated that 33,000 and 35,000 people die yearly in Europe and the United States, respectively, as a direct result of antimicrobial resistance. For all these reasons, there is an emerging need to find novel alternatives to overcome these issues and reduced the morbidity and mortality associated to bacterial infectious diseases. In that sense, nanotechnological approaches, especially smart polymeric nanoparticles, has wrought a revolution in this field, providing an innovative therapeutic alternative able to improve the limitations encountered in available treatments and capable to be effective by theirselves. In this review, we examine the current status of most dangerous human infections, together with an in-depth discussion of the role of nanomedicine to overcome the current disadvantages, and specifically the most recent and innovative studies involving polymeric nanoparticles against most common bacterial infections of the human body.

Serologic markers of Chlamydia trachomatis and other sexually transmitted infections and subsequent ovarian cancer risk: Results from the EPIC cohort

A substantial proportion of epithelial ovarian cancer (EOC) arises in the fallopian tube and other epithelia of the upper genital tract; these epithelia may incur damage and neoplastic transformation after sexually transmitted infections (STI) and pelvic inflammatory disease. We investigated the hypothesis that past STI infection, particularly Chlamydia trachomatis, is associated with higher EOC risk in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort including 791 cases and 1669 matched controls. Serum antibodies against C. trachomatis, Mycoplasma genitalium, herpes simplex virus type 2 (HSV-2) and human papillomavirus (HPV) 16, 18 and 45 were assessed using multiplex fluorescent bead-based serology. Conditional logistic regression was used to estimate relative risks (RR) and 95% confidence intervals (CI) comparing women with positive vs. negative serology. A total of 40% of the study population was seropositive to at least one STI. Positive serology to C. trachomatis Pgp3 antibodies was not associated with EOC risk overall, but with higher risk of the mucinous histotype (RR = 2.30 [95% CI = 1.22-4.32]). Positive serology for chlamydia heat shock protein 60 (cHSP60-1) was associated with higher risk of EOC overall (1.36 [1.13-1.64]) and with the serous subtype (1.44 [1.12-1.85]). None of the other evaluated STIs were associated with EOC risk overall; however, HSV-2 was associated with higher risk of endometrioid EOC (2.35 [1.24-4.43]). The findings of our study suggest a potential role of C. trachomatis in the carcinogenesis of serous and mucinous EOC, while HSV-2 might promote the development of endometrioid disease.

Shift work influences the outcomes of Chlamydia infection and pathogenesis

Shift work, performed by approximately 21 million Americans, is irregular or unusual work schedule hours occurring after 6:00 pm. Shift work has been shown to disrupt circadian rhythms and is associated with several adverse health outcomes and chronic diseases such as cancer, gastrointestinal and psychiatric diseases and disorders. It is unclear if shift work influences the complications associated with certain infectious agents, such as pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility resulting from genital chlamydial infection. We used an Environmental circadian disruption (ECD) model mimicking circadian disruption occurring during shift work, where mice had a 6-h advance in the normal light/dark cycle (LD) every week for a month. Control group mice were housed under normal 12/12 LD cycle. Our hypothesis was that compared to controls, mice that had their circadian rhythms disrupted in this ECD model will have a higher Chlamydia load, more pathology and decreased fertility rate following Chlamydia infection. Results showed that, compared to controls, mice that had their circadian rhythms disrupted (ECD) had higher Chlamydia loads, more tissue alterations or lesions, and lower fertility rate associated with chlamydial infection. Also, infected ECD mice elicited higher proinflammatory cytokines compared to mice under normal 12/12 LD cycle. These results imply that there might be an association between shift work and the increased likelihood of developing more severe disease from Chlamydia infection.

Prevalence of Chlamydia trachomatis in an asymptomatic female population attending cervical cytology services of three healthcare centers in Medellín, Colombia

Introducción.

La infección de transmisión sexual causada por Chlamydia trachomatis es la más frecuente de etiología bacteriana en el mundo. Aunque puede ser asintomática en la mayoría de los casos, C. trachomatis puede generar diversos problemas de salud reproductiva en mujeres, como cervicitis, endometritis y salpingitis. A pesar de su importancia, en Medellín no se cuenta con suficientes datos epidemiológicos sobre esta infección.

Objetivo.

Determinar la prevalencia de C. trachomatis en mujeres de Medellín, determinar los posibles factores de riesgo y evaluar la relación con la infección por el virus de papiloma humano (HPV).

Materiales y métodos.

Se hizo un estudio transversal multicéntrico para detectar la infección por C. trachomatis en 1.282 mujeres mediante reacción en cadena de la polimerasa (PCR) convencional y el estuche comercial LightMix 480 HT CT/NG™ (Roche, Basilea, Suiza).

Resultados.

La prevalencia total de la infección por C. trachomatis fue de 4,1 % (IC_95% 2,9-5,3). Se encontró una relación significativa de la infección con la edad, el consumo de cigarrillo y el uso de anticonceptivos hormonales.

Conclusión.

La prevalencia de la infección es similar a la reportada en otros lugares del país y del mundo, siendo las mujeres más jóvenes las más afectadas. En cuanto a la presentación del HPV, no se encontró ningún tipo de relación con C. trachomatis.

Recent Advances in Polymeric Nanoparticle-Encapsulated Drugs against Intracellular Infections

Polymeric nanocarriers (PNs) have demonstrated to be a promising alternative to treat intracellular infections. They have outstanding performance in delivering antimicrobials intracellularly to reach an adequate dose level and improve their therapeutic efficacy. PNs offer opportunities for preventing unwanted drug interactions and degradation before reaching the target cell of tissue and thus decreasing the development of resistance in microorganisms. The use of PNs has the potential to reduce the dose and adverse side effects, providing better efficiency and effectiveness of therapeutic regimens, especially in drugs having high toxicity, low solubility in the physiological environment and low bioavailability. This review provides an overview of nanoparticles made of different polymeric precursors and the main methodologies to nanofabricate platforms of tuned physicochemical and morphological properties and surface chemistry for controlled release of antimicrobials in the target. It highlights the versatility of these nanosystems and their challenges and opportunities to deliver antimicrobial drugs to treat intracellular infections and mentions nanotoxicology aspects and future outlooks.

MYCO WELL D-ONE detection of Ureaplasma spp. and Mycoplasma hominis in sexual health patients in Wales

The genital mycoplasmas are a unique group of inherently antibiotic-resistant sexually transmitted bacteria, often associated with non-gonococcal urethritis and bacterial vaginosis. The MYCO WELL D-ONE is a culture-based assay that aims to detect these organisms whilst concurrently screening them for antibiotic resistance. Urine and/or swabs from 856 informed and consented participants attending Welsh sexual health clinics were subjected to MYCO WELL D-ONE analysis, alongside qPCR and culture titration methodologies to determine sensitivity, specificity, PPV, NPV and accuracy. Resistance was confirmed by CLSI-compliant susceptibility testing and genetic mechanisms determined. The MYCO WELL D-ONE displayed a sensitivity and specificity of 91.98% and 96.44% for the detection of Ureaplasma spp., with sensitivity and specificity values of 78.23% and 98.84% for Mycoplasma hominis, compared with qPCR. Swabs harboured significantly greater bacterial loads than urine samples for both Ureaplasma spp. and M. hominis. Levofloxacin resistance rates, mediated by Ser83Leu mutation in ParC, for Ureaplasma spp. were 0.54%. Tetracycline resistance rates, mediated by tet(M), were 0.54% and 2% for Ureaplasma spp. and M. hominis, respectively; sequence analysis of tet(M)-positive Ureaplasma spp. and M. hominis strains isolated from a single individual confirmed separate resistance gene origins. The MYCO WELL D-ONE is a sensitive and specific assay for the detection of Ureaplasma spp. and M. hominis in genitourinary medicine samples, facilitating the accurate detection of these organisms within low-technology environments. While good for antibiotic resistance screening, accurate confirmation by MIC determination or molecular methods are required, and more optimally performed on urine samples.

Low-dose doxycycline induces Chlamydia trachomatis persistence in HeLa cells

Chlamydia persistence is a viable but non-replicative stage, induced by several sub-lethal stressor agents, including beta-lactam antibiotics. So far, no data about the connection between doxycycline and chlamydial persistence has been described in literature. We investigated the ability of doxycycline to induce C. trachomatis (CT) persistence in an in vitro model of epithelial cell infection (HeLa cells), comparing the results with the well-established model of penicillin-induced persistence. The effect of doxycycline was explored on 10 different CT strains by analysing (i) the presence of aberrant inclusions, (ii) chlamydial recovery, (iii) the expression of different chlamydial genes (omcB, euo, Ct110, Ct604, Ct755, HtrA) and (iv) the effects on epithelial cell viability. For each strain, the presence of foreign genomic islands responsible of tetracycline resistance was excluded. We found that low doses of doxycycline can induce a condition of CT persistence. For concentrations of doxycycline equal to 0.03-0.015 mg/L, CT inclusions are smaller and aberrant and CT cycle is characterized by the presence of viable but non-dividing RBs with the complete abolishment of chlamydial cytotoxic effect. Infectious EBs can be recovered after removal of the drug. During doxycycline-induced persistence, the expression of the late gene omcB is decreased, indicating the blocking of RB-to-EB conversion. Conversely, as for penicillin G, a significant up-regulation of the stress response HtrA gene is found in doxycycline-treated cells. This study provides a novel in vitro cell model to examine the characteristics of doxycycline-induced persistent CT infection.

Chlamydia trachomatis and Human Papillomavirus Infection in Women From Southern Hunan Province in China: A Large Observational Study

Chlamydia trachomatis and human papillomavirus (HPV) are the most common pathogens of sexually transmitted infections (STIs), which can increase the risk of cervical cancer and infertility. The purpose of this study was to evaluate the prevalence, genotype and risk factors of C. trachomatis and/or HPV infection in women attending the annual physical examination, assistant reproductive treatment and visiting the gynecology clinics from Southern Hunan province in China. Cervical-swab samples were collected from 5006 participants. We found that the overall prevalence of C. trachomatis, HPV infection and C. trachomatis/HPV coinfection was 4.7% (236/5006), 15.5% (778/5006) and 1.2% (59/5006), while the prevalence of asymptomatic infection of that was 3.8% (38/1006), 10.8% (109/1006) and 0.6% (6/1006), respectively. Furthermore, 25.0% (59/236) of C. trachomatis infection and 7.6% (59/778) of HPV infection were attributable to C. trachomatis and HPV coinfection. C. trachomatis and HPV infection were more often observed in young women of less than 25 years (10.4% and 21.3%, respectively) and in the outpatients from gynecology clinics (5.2% and 18.0%, respectively). Of note, a higher prevalence of C. trachomatis infection was observed in HPV-positive women (7.6%) than HPV- negative ones (4.2%), and vice versa. The top three C. trachomatis genotypes were E (1.4%), F (1.1%) and J (0.8%), and the counterparts of HPV genotypes were HPV52 (4.2%), HPV16 (2.3%) and HPV58 (2.2%), respectively. Among the 151 outpatients with colposcopy data, HPV infection was associated with severe cervical lesions with OR of 15.86 (95% CI 3.14–80.0, P < 0.001) while C. trachomatis infection was more likely associated with a low grade colposcopy impression (OR = 3.25, 95% CI: 1.22–8.65, P = 0.018). Our data highlight the high prevalence of asymptomatic C. trachomatis and HPV infection, particularly among women of <25 years. The two pathogens may serve as mutual risk factors to increase the risk of infections and cervical lesions. Widespread implementation of HPV and C. trachomatis screening programs, especially for young women, would be an effective strategy to relieve the burden of sexually transmitted infections.

Progress and Perspectives in Point of Care Testing for Urogenital Chlamydia trachomatis Infection: A Review

Worldwide, genital infection with Chlamydia trachomatis (C. trachomatis) is one of the most common sexually transmitted infections. Most infections are asymptomatic. However, particularly in women, untreated infection with C. trachomatis can lead to complications that include pelvic inflammatory disease, infertility, and tubal ectopic pregnancy. Rapid methods for early and accurate diagnosis for infection with C. trachomatis that can be performed in the clinic would allow for earlier treatment to prevent complications. Traditional laboratory-based tests for C. trachomatis infection include culture, enzyme immunoassay, direct immunofluorescence, nucleic acid hybridization, and nucleic acid amplification tests, which take time but have high diagnostic sensitivity. Novel and rapid diagnostic tests include extraordinary optical transmission (EOT), loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA), and microwave-accelerated metal-enhanced fluorescence (MAMEF). Although these new tests offer the promise of rapid screening and diagnosis, they may have lower diagnostic sensitivity. This review aims to provide an overview of traditional methods for the diagnosis of urogenital infection with C. trachomatis, the current status of POC testing for urogenital C. trachomatis infection and discusses recent progress and perspectives.

Insights into penicillin-induced Chlamydia trachomatis persistence

Chlamydia persistence is a viable, but non-cultivable, growth stage, resulting in a long-term relationship with the infected host cell. In vitro, this condition can be induced by different stressor agents, including beta-lactam antibiotics, as penicillin. The aim of this study was to get new insights into the interactions between Chlamydia trachomatis (serovars D and L2) and the epithelial host cells (HeLa) during persistence condition. In particular, we evaluated the following aspects, by comparing the normal chlamydial development cycle with penicillin-induced persistence: (i) cell survival/death, (ii) externalization of phosphatidylserine, (iii) caspase 1 and caspase 3/7 activation, and (iv) reactive oxygen species (ROS) production by the infected cells. At 72 h post-infection, the cytotoxic effect displayed by CT was completely abolished for both serovars and for all levels of multiplicity of infection only in the cells with aberrant CT inclusions. At the same time, CT was able to switch off the exposure of the lipid phosphatidylserine on the surface of epithelial cells and to strongly inhibit the activation of caspase 1 and caspase 3/7 only in penicillin-treated cells. Forty-eight hours post-infection, CT elicited a significant ROS expression both in case of a normal cycle and in case of persistence. However, serovar L and penicillin-free infection activated a higher ROS production compared to serovar D and to penicillin-induced persistence, respectively. In conclusion, we added knowledge to the cellular dynamics taking place during chlamydial persistence, demonstrating that CT creates a suitable niche to survive, switching off signals able to activate phagocytes/leukocytes recruitment. Nevertheless, persistent CT elicits ROS production by the infected cells, potentially contributing to the onset of chronic inflammation and tissue damages.

Impact of genital Chlamydia trachomatis infection on reproductive outcomes among infertile women undergoing tubal flushing: a retrospective cohort at a fertility centre in Uganda

Background

The impact of current C. trachomatis on clinical pregnancy and live birth rates among women undergoing tubal flushing is largely unknown. This study aimed to investigate whether current female genital C. trachomatis infection affects the chance of achieving a clinical pregnancy and a live birth, among infertile women undergoing tubal flushing, at a fertility centre in Uganda.

Methods

A retrospective Cohort study at a peri-urban fertility centre. A total of 253 eligible women with tubal factor infertility, who underwent tubal flushing, were enrolled and categorised according to their exposure to current genital C. trachomatis infection. These women were followed up for a period of 12 months, with the primary outcome measure being clinical pregnancy and live birth. Secondary outcome measures included pregnancy loss and procedural related adverse events.

Results

Exposure to current genital C. trachomatis infection reduced chance of clinical pregnancy (adjusted relative risk 0.42; 95% confidence interval, 0.18–0.96) and a live birth (adjusted relative risk 0.37; 95% confidence interval, 0.14–0.95) after tubal flushing. Women with current C. trachomatis infection had an increased risk of adverse events (adjusted relative risk, 1.20; 95% confidence interval, 1.08–1.34). However, current C. trachomatis infection did not affect the risk of spontaneous abortion and ectopic pregnancy.

Conclusion

Current genital C. trachomatis infection in women with tubal factor infertility, undergoing tubal flushing, lowers their chance of pregnancy and live birth.

Bacterial Load of Chlamydia trachomatis in the Posterior Oropharynx, Tonsillar Fossae, and Saliva among Men Who Have Sex with Men with Untreated Oropharyngeal Chlamydia

The aim of this study was to determine whether Chlamydia trachomatis could be detected in saliva and if infection is specific to an anatomical site in the oropharynx. Men who have sex with men (MSM) who were diagnosed with oropharyngeal chlamydia at the Melbourne Sexual Health Centre in 2017-2018 were invited to participate upon returning for treatment. Swabs at the tonsillar fossae and posterior oropharynx and a saliva sample were collected. Throat samples were tested for C. trachomatis by the Aptima Combo 2 assay. The bacterial loads of C. trachomatis in all samples were assessed by quantitative PCR (qPCR) detecting the ompA gene. We calculated the positivity and bacterial load of C. trachomatis for all samples. Forty-two MSM were included. The median age was 28 years (interquartile range [IQR], 24 to 33 years). Thirty-two participants (76.2%; 95% confidence interval [CI], 60.5% to 87.9%) had C. trachomatis detected by qPCR at both the tonsillar fossae and the posterior oropharynx, followed by 9.5% (n = 4; 95% CI, 2.7% to 22.6%) positive at the posterior oropharynx only and 4.8% (n = 2; 95% CI, 0.58% to 16.2%) positive at the tonsillar fossae only. Twenty-nine MSM had C. trachomatis detected in saliva (69.0%; 95% CI, 52.9% to 82.3%). The median C. trachomatis load in saliva was 446 copies/ml (IQR, 204 to 1,390 copies/ml), that in the tonsillar fossae was 893 copies/swab (IQR, 390 to 13,224 copies/ml), and that in the posterior oropharynx was 1,204 copies/swab (IQR, 330 to 16,211). There was no significant difference in C. trachomatis load between the tonsillar fossae and the posterior oropharynx (P = 0.119). Among MSM with oropharyngeal chlamydia, nearly three-quarters had chlamydia DNA detected in saliva, although the viability and implications for transmission are unknown.

Toll-Like Receptor 3 Deficiency Leads to Altered Immune Responses to Chlamydia trachomatis Infection in Human Oviduct Epithelial Cells

Reproductive tract pathology caused by Chlamydia trachomatis infection is an important global cause of human infertility. To better understand the mechanisms associated with Chlamydia-induced genital tract pathogenesis in humans, we used CRISPR genome editing to disrupt Toll-like receptor 3 (TLR3) function in the human oviduct epithelial (hOE) cell line OE-E6/E7 in order to investigate the possible role(s) of TLR3 signaling in the immune response to Chlamydia Disruption of TLR3 function in these cells significantly diminished the Chlamydia-induced synthesis of several inflammation biomarkers, including interferon beta (IFN-β), interleukin-6 (IL-6), interleukin-6 receptor alpha (IL-6Rα), soluble interleukin-6 receptor beta (sIL-6Rβ, or gp130), IL-8, IL-20, IL-26, IL-34, soluble tumor necrosis factor receptor 1 (sTNF-R1), tumor necrosis factor ligand superfamily member 13B (TNFSF13B), matrix metalloproteinase 1 (MMP-1), MMP-2, and MMP-3. In contrast, the Chlamydia-induced synthesis of CCL5, IL-29 (IFN-λ1), and IL-28A (IFN-λ2) was significantly increased in TLR3-deficient hOE cells compared to their wild-type counterparts. Our results indicate a role for TLR3 signaling in limiting the genital tract fibrosis, scarring, and chronic inflammation often associated with human chlamydial disease. Interestingly, we saw that Chlamydia infection induced the production of biomarkers associated with persistence, tumor metastasis, and autoimmunity, such as soluble CD163 (sCD163), chitinase-3-like protein 1, osteopontin, and pentraxin-3, in hOE cells; however, their expression levels were significantly dysregulated in TLR3-deficient hOE cells. Finally, we demonstrate using hOE cells that TLR3 deficiency resulted in an increased amount of chlamydial lipopolysaccharide (LPS) within Chlamydia inclusions, which is suggestive that TLR3 deficiency leads to enhanced chlamydial replication and possibly increased genital tract pathogenesis during human infection.

First Report of Chlamydia Seroprevalence in Slaughter Pigs in Shandong Province, Eastern China

Chlamydia, a kind of obligate intracellular Gram-negative bacteria, can infect humans and animals worldwide, including pigs. However, the information on Chlamydia infection is unavailable in pigs in Shandong province, eastern China. To assess the seroprevalence and risk factors of Chlamydia infection in pigs in Shandong province, eastern China, a total of 2108 serum samples of slaughter pigs were collected between January 2017 and December 2018, and specific antibodies against Chlamydia were detected by the indirect hemagglutination assay. The overall Chlamydia seroprevalence was 24.15% (509/2108, 95% confidence interval: 22.32-25.97). Species, sampling regions, and rearing systems of pigs were considered as risk factors for Chlamydia infection through statistical analysis by SAS analysis (p < 0.05). These results indicated that Chlamydia is highly prevalent in slaughter pigs in Shandong province, eastern China, and may pose a potential risk for human health. To our knowledge, this is the first investigation of Chlamydia seroprevalence in slaughter pigs in Shandong province, eastern China. Moreover, this is the first report to compare the Chlamydia seroprevalence between domestic pigs and farmed wild boars in a same study, which may provide important data for preventing and controlling Chlamydia infection in pigs in China.

Diagnosing sexually transmitted infections in resource-constrained settings: challenges and ways forward

INTRODUCTION

Sexually transmitted infections (STIs) remain prevalent and are increasing in several populations. Appropriate STI diagnosis is crucial to prevent the transmission and sequelae of untreated infection. We reviewed the diagnostic accuracy of syndromic case management and existing point-of-care tests (POCTs), including those in the pipeline, to diagnose STIs in resource-constrained settings.

METHODS

We prioritized updating the systematic review and meta-analysis of the diagnostic accuracy of vaginal discharge from 2001 to 2015 to include studies until 2018. We calculated the absolute effects of different vaginal flowcharts and the diagnostic performance of POCTs on important outcomes. We searched the peer-reviewed literature for previously conducted systematic reviews and articles from 1990 to 2018 on the diagnostic accuracy of syndromic management of vaginal and urethral discharge, genital ulcer and anorectal infections. We conducted literature reviews from 2000 to 2018 on the existing POCTs and those in the pipeline.

RESULTS AND DISCUSSIONS

The diagnostic accuracy of urethral discharge and genital ulcer disease syndromes is relatively adequate. Asymptomatic Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections limit the use of vaginal discharge and anorectal syndromes. The pooled diagnostic accuracy of vaginal syndromic case management for CT/NG is low, resulting in high numbers of overtreatment and missed treatment. The absolute effect of POCTs was reduced overtreatment and missed treatment. Findings of the reviews on syndromic case management underscored the need for low-cost and accurate POCTs for the identification, first, of CT/NG, and, second, of Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV) and NG and MG resistance/susceptibility testing. Near-patient POCT molecular assays for CT/NG/TV are commercially available. The prices of these POCTs remain the barrier for uptake in resource-constrained settings. This is driving the development of lower cost solutions.

CONCLUSIONS

The WHO syndromic case management guidelines should be updated to raise the quality of STI management through the integration of laboratory tests. STI screening strategies are needed to address asymptomatic STIs. POCTs that are accurate, rapid, simple and affordable are urgently needed in resource-constrained settings to support the uptake of aetiological diagnosis and treatment.

Anti-chlamydial activities of cell-permeable hydrophobic dipeptide-containing derivatives

The obligate intracellular bacteria chlamydia is major human pathogen that causes millions of trachoma, sexually transmitted infections and pneumonia worldwide. We serendipitously found that both calpain inhibitors z-Val-Phe-CHO and z-Leu-Nle-CHO showed marked inhibitory activity against chlamydial growth in human epithelial HeLa cells, whereas other calpain inhibitors not. These peptidomimetic inhibitors consist of N-benzyloxycarbonyl group and hydrophobic dipeptide derivatives. Both compounds strongly restrict the chlamydial growth even addition at the 12 h post infection. Notably, inhibitors-mediated growth inhibition of chlamydia was independent on host calpain activity. Electron microscopic analysis revealed that z-Val-Phe-CHO inhibited chlamydial growth by arresting bacterial cell division and RB-EB re-transition, but not by changing into persistent state. We searched and found that z-Leu-Leu-CHO and z-Phe-Ala-FMK also inhibited chlamydial growth. Neither biotin-hydrophobic dipeptide nor morpholinoureidyl-hydrophobic dipeptide shows inhibitory effects on chlamydial intracellular growth. Our results suggested the possibility of some chemical derivatives based on z-hydrophobic dipeptide group for future therapeutic usage to the chlamydial infectious disease.

The Anti-Inflammatory Effect of Feiyangchangweiyan Capsule and Its Main Components on Pelvic Inflammatory Disease in Rats via the Regulation of the NF-κB and BAX/BCL-2 Pathway

Although gastroenteritis and pelvic inflammatory disease (PID) occur in the gastrointestinal tract and pelvis, respectively, they display similar pathogeneses. The incidence of inflammation in these conditions is usually associated with dysbacteriosis, and, at times, they are caused by the same pathogenic bacteria, Escherichia coli and Streptococcus aureus. Feiyangchangweiyan capsule (FYC) is a traditional Chinese patent medicine that is widely used to treat bacterial dysentery and acute and chronic gastroenteritis. However, whether it has an effect on PID is unclear. The aim of this study was to investigate the anti-inflammatory effect of FYC and its main components, gallic acid (GA), ellagic acid (EA), and syringin (SY), on a pathogen-induced PID model and illustrate their potential mechanism of action. Female specific pathogen-free SD rats (n = 1110) were randomly divided into control, PID, FYC, GA, EA, SY, GA + EA, GA + SY, EA + SY, GA + EA + SY, and Fuke Qianjin capsule (FKC) positive groups. Histological examination and enzyme-linked immunosorbent assay (ELISA) were carried out as well as western blot analysis to detect the expression of NF-κB, BAX, BCL-2, and JNK. In this study, FYC and its main components dramatically suppressed the infiltration of inflammatory cells, reduced the production of IL-1β, TNF-α, and MCP-1, and elevated the IL-10 level to varying degrees. We also found that FYC and its main components inhibited the expression of BAX induced by infection and increased the expression of Bcl-2. FYC, GA, EA, and SY could also block the activation of the NF-κB pathway. Finally, we found that the phosphorylation of JNK could be decreased by FYC, GA, and SY. FYC and its main components exhibit anti-inflammatory effect on a pathogen-induced PID model by regulating the NF-κB and apoptosis signaling pathways.

Selected Immunological Mediators and Cervical Microbial Signatures in Women with Chlamydia trachomatis Infection

In the female genital ecosystem, the complex interplay between the host immune system and the resident microflora protects against urogenital pathogens, like Chlamydia trachomatis C. trachomatis is responsible for urethritis and cervicitis; however, most chlamydial infections are asymptomatic and, thus, not treated, potentially leading to severe reproductive sequelae. Here we investigated the interaction between the levels of selected immune mediators and the community state types of the cervical microbiota in C. trachomatis-infected women. Cervical samples from 42 C. trachomatis-positive women and 103 matched healthy controls were analyzed through the metagenomic analysis of the hypervariable region v4 of the 16S rRNA gene and the determination of lactoferrin, interleukin 1α (IL-1α), IL-6, alpha interferon (IFN-α), IFN-β, and IFN-γ by ELISA. Overall, C. trachomatis infection was significantly associated with a microbiota dominated by anaerobic bacteria (P = 0.000002). In addition, a network of Gardnerella vaginalis, Prevotella amnii, Prevotella buccalis, Prevotella timonensis, Aerococcus christensenii, and Variovorax guangxiensis has been identified as a potential biomarker of C. trachomatis infection through multiple statistical approaches. Again, chlamydial infection was significantly correlated with an increased production of lactoferrin, IL-6, IL-1α, IFN-α, and IFN-β (P < 0.05), whereas very low levels of IFN-γ were observed in C. trachomatis-infected women, levels similar to those detected in healthy women. Our findings show a distinctive signature of C. trachomatis genital infection, characterized by a specific bacterial network, constituted by anaerobes, as well as by increased levels of lactoferrin and proinflammatory cytokines (IL-1α, IL-6, IFN-α, and IFN-β), accompanied by low levels of IFN-γ.IMPORTANCE To our knowledge, this is the first study that investigated the association of C. trachomatis with the cervical levels of lactoferrin and selected inflammatory mediators and their correlation with the different community state types characterizing the female genital ecosystem. C. trachomatis, known as the leading cause of bacterial sexually transmitted diseases, continues to be an important public health problem worldwide for its increasing incidence and the risk of developing severe reproductive sequelae, like pelvic inflammatory disease and infertility. Specifically, C. trachomatis tend to persist in the female genital tract, leading to a chronic inflammatory state characterized by increased production of immune mediators responsible for tissue damage. Therefore, our study may help to broaden the knowledge on the complex interplay between the female genital microbiota and the host immune system in response to C. trachomatis infection.

Chlamydiaceae: Diseases in Primary Hosts and Zoonosis

Bacteria of the Chlamydiaceae family are a type of Gram-negative microorganism typified by their obligate intracellular lifestyle. The majority of the members in the Chlamydiaceae family are known pathogenic organisms that primarily infect the host mucosal surfaces in both humans and animals. For instance, Chlamydia trachomatis is a well-known etiological agent for ocular and genital sexually transmitted diseases, while C. pneumoniae has been implicated in community-acquired pneumonia in humans. Other chlamydial species such as C. abortus, C. caviae, C. felis, C. muridarum, C. pecorum, and C. psittaci are important pathogens that are associated with high morbidities in animals. Importantly, some of these animal pathogens have been recognized as zoonotic agents that pose a significant infectious threat to human health through cross-over transmission. The current review provides a succinct recapitulation of the characteristics as well as transmission for the previously established members of the Chlamydiaceae family and a number of other recently described chlamydial organisms.

Akt/AS160 Signaling Pathway Inhibition Impairs Infection by Decreasing Rab14-Controlled Sphingolipids Delivery to Chlamydial Inclusions

Chlamydia trachomatis, an obligate intracellular bacterium, intercepts different trafficking pathways of the host cell to acquire essential lipids for its survival and replication, particularly from the Golgi apparatus via a Rab14-mediated transport. Molecular mechanisms underlying how these bacteria manipulate intracellular transport are a matter of intense study. Here, we show that C. trachomatis utilizes Akt/AS160 signaling pathway to promote sphingolipids delivery to the chlamydial inclusion through Rab14-controlled vesicular transport. C. trachomatis provokes Akt phosphorylation along its entire developmental life cycle and recruits phosphorylated Akt (pAkt) to the inclusion membrane. As a consequence, Akt Substrate of 160 kDa (AS160), also known as TBC1D4, a GTPase Activating Protein (GAP) for Rab14, is phosphorylated and therefore inactivated. Phosphorylated AS160 (pAS160) loses its ability to promote GTP hydrolysis, favoring Rab14 binding to GTP. Akt inhibition by an allosteric isoform-specific Akt inhibitor (iAkt) prevents AS160 phosphorylation and reduces Rab14 recruitment to chlamydial inclusions. iAkt further impairs sphingolipids acquisition by C. trachomatis-inclusion and provokes lipid retention at the Golgi apparatus. Consequently, treatment with iAkt decreases chlamydial inclusion size, bacterial multiplication, and infectivity in a dose-dependent manner. Similar results were found in AS160-depleted cells. By electron microscopy, we observed that iAkt generates abnormal bacterial forms as those reported after sphingolipids deprivation or Rab14 silencing. Taken together, our findings indicate that targeting the Akt/AS160/Rab14 axis could constitute a novel strategy to limit chlamydial infections, mainly for those caused by antibiotic-resistant bacteria.

Prevalence of Chlamydia trachomatis Infection Diagnosed by Polymerase Chain Reaction in Female Sex Workers in a Northern Mexican City

Purpose

We aimed to determine the association between Chlamydia trachomatis infection and female sex work, and the association between sociodemographic, obstetric, and behavioral characteristics of female sex workers and C. trachomatis infection.

Methods

Through a case–control study design, we studied 201 female sex workers and 201 age-matched women without sex work in Durango City, Mexico. C. trachomatis DNA was detected in cervical swab samples using polymerase chain reaction.

Results

C. trachomatis DNA was detected in 32 (15.9%) of the 201 cases and in 6 (3.0%) of the 201 controls (odds ratio [OR] = 6.15; 95% confidence interval [CI]: 2.5–15.0; P < 0.001). The frequency of infection with C. trachomatis in female sex workers did not vary (P > 0.05) regardless of the history of pregnancies, deliveries, cesarean sections, or miscarriages. Regression analysis of the behavioral characteristics showed that infection with C. trachomatis was associated only with consumption of alcohol (OR = 2.39; 95% CI: 1.0–5.71; P = 0.04). Conclusions: We conclude that C. trachomatis infection is associated with female sex work in Durango City, Mexico. This is the first age-matched case–control study on the prevalence of C. trachomatis infection in female sex workers in Mexico using detection of C. trachomatis DNA in cervical samples.

IL-10 Producing B Cells Dampen Protective T Cell Response and Allow Chlamydia muridarum Infection of the Male Genital Tract

A significant proportion of individuals develop chronic, persistent and recurrent genital tract infections with Chlamydia trachomatis, which has been attributed to the numerous strategies that the bacterium uses to subvert host immune responses. Animal chlamydia models have demonstrated that protective immune response is mediated by CD4⁺ Th1 cytokine responses. Herein, we demonstrate that early after infecting the male genital tract, C. muridarum triggers the production of IL-10 by splenic and lymph node cells. In addition, C. muridarum triggers IL-6 and TNFα secretion. Data obtained from in vitro and in vivo experiments revealed B cells as the major IL-10 contributors. Indeed, purified B cells produced high amounts of IL-10 and also exhibited enhanced expression of inhibitory molecules such as CD39, PD-L1 and PD1 after C. muridarum stimulation. In vitro experiments performed with sorted cell subsets revealed that Marginal Zone B cells were the main IL-10 producers. In vitro and in vivo studies using TLR-deficient mice indicated that TLR4 signaling pathway was essential for IL-10 production. In addition, in vivo treatments to neutralize IL-10 or deplete B cells indicated that IL-10 and B cells played a significant role in delaying bacterial clearance ability. Moreover, the latter was confirmed by adoptive cell transfer experiments in which the absence of IL-10-producing B cells conferred the host a greater capability to induce Th1 responses and clear the infection. Interestingly, NOD mice, which were the least efficient in clearing the infection, presented much more Marginal Zone B counts and also enhanced TLR4 expression on Marginal Zone B cells when compared to B6 and BALB/c mice. Besides, treatment with antibodies that selectively deplete Marginal Zone B cells rendered mice more capable of inducing enhanced IFNγ responses and clearing the infection. Our findings suggest that B cells play a detrimental role in C. muridarum infection and that activation by innate receptors like TLR4 and IL-10 production by these cells could be used by Chlamydia spp. as a strategy to modulate the immune response establishing chronic infections in susceptible hosts.

Chlamydia trachomatis Growth and Cytokine mRNA Response in a Prostate Cancer Cell Line

In the present paper, we report that C. trachomatis can be efficiently propagated and affect mRNA expression for two major cytokines, relevant to tumor progression, in CWR-R1 cells, a malignant prostate cell line. CWR-R1 and McCoy cells, a classic cell line for chlamydial research, were grown and infected with C. trachomatis under similar conditions. Cell monolayers were harvested for RNA analysis and immunostaining with major outer membrane protein (MOMP) antibody at 24, 48, and 72 hours of the postinfection (hpi) period. It was shown that the infectious cycle of chlamydial pathogen in CWR-R1 cells resembles the progression of C. trachomatis infection in McCoy cells but with a few important differences. First of all, the initial stage of C. trachomatis propagation in CWR-R1 cells (24 hpi) was characterized by larger inclusion bodies and more intense, specific immunofluorescent staining of infected cells as compared with McCoy cells. Moreover, there was a corresponding increase in infective progeny formation in CWR-R1 cells along with mRNA for EUO, a crucial gene controlling the early phase of the chlamydial development cycle (24 hpi). These changes were more minimal and became statistically insignificant at a later time point in the infectious cycle (48 hpi). Altogether, these data suggest that the early phase of C. trachomatis infection in CWR-R1 cells is accompanied by more efficient propagation of the pathogen as compared with the growth of C. trachomatis in McCoy cells. Furthermore, propagation of C. trachomatis in CWR-R1 cells leads to enhanced transcription of interleukin-6 and fibroblast growth factor-2, genes encoding two important proinflammatory cytokines implicated in the molecular mechanisms of chemoresistance of prostate cancer and its ability to metastasize. The possible roles of reactive oxygen species and impaired mitochondrial oxidation in the prostate cancer cell line are discussed as factors promoting the early stages of C. trachomatis growth in CWR-R1 cells.