-
Nature Reviews. Microbiology Jun 2016Chlamydia spp. are important causes of human disease for which no effective vaccine exists. These obligate intracellular pathogens replicate in a specialized membrane... (Review)
Review
Chlamydia spp. are important causes of human disease for which no effective vaccine exists. These obligate intracellular pathogens replicate in a specialized membrane compartment and use a large arsenal of secreted effectors to survive in the hostile intracellular environment of the host. In this Review, we summarize the progress in decoding the interactions between Chlamydia spp. and their hosts that has been made possible by recent technological advances in chlamydial proteomics and genetics. The field is now poised to decipher the molecular mechanisms that underlie the intimate interactions between Chlamydia spp. and their hosts, which will open up many exciting avenues of research for these medically important pathogens.
Topics: Bacterial Proteins; Chlamydia; Chlamydia Infections; Chlamydia trachomatis; Cytoplasm; Host-Pathogen Interactions; Humans; Immunity, Innate; Proteomics; Type V Secretion Systems
PubMed: 27108705
DOI: 10.1038/nrmicro.2016.30 -
Vaccine May 2021Chlamydia trachomatis is the causative agent of a highly prevalent sexually transmitted bacterial disease and is associated with a number of severe disease... (Review)
Review
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.
Topics: Animals; Bacterial Vaccines; CD4-Positive T-Lymphocytes; Chlamydia Infections; Chlamydia trachomatis; Humans; Vaccination
PubMed: 33771390
DOI: 10.1016/j.vaccine.2021.03.043 -
Clinical and Vaccine Immunology : CVI Oct 2017is an obligate intracellular bacterium whose only natural host is humans. Although presenting as asymptomatic in most women, genital tract chlamydial infections are a... (Review)
Review
is an obligate intracellular bacterium whose only natural host is humans. Although presenting as asymptomatic in most women, genital tract chlamydial infections are a leading cause of pelvic inflammatory disease, tubal factor infertility, and ectopic pregnancy. has evolved successful mechanisms to avoid destruction by autophagy and the host immune system and persist within host epithelial cells. The intracellular form of this organism, the reticulate body, can enter into a persistent nonreplicative but viable state under unfavorable conditions. The infectious form of the organism, the elementary body, is again generated when the immune attack subsides. In its persistent form, ceases to produce its major structural and membrane components, but synthesis of its 60-kDa heat shock protein (hsp60) is greatly upregulated and released from the cell. The immune response to hsp60, perhaps exacerbated by repeated cycles of productive infection and persistence, may promote damage to fallopian tube epithelial cells, scar formation, and tubal occlusion. The chlamydial and human hsp60 proteins are very similar, and hsp60 is one of the first proteins produced by newly formed embryos. Thus, the development of immunity to epitopes in the chlamydial hsp60 that are also present in the corresponding human hsp60 may increase susceptibility to pregnancy failure in infected women. Delineation of host factors that increase the likelihood that will avoid immune destruction and survive within host epithelial cells and utilization of this knowledge to design individualized preventative and treatment protocols are needed to more effectively combat infections by this persistent pathogen.
Topics: Asymptomatic Infections; Chaperonin 60; Chlamydia Infections; Chlamydia trachomatis; Female; Host-Pathogen Interactions; Humans; Infertility; Pelvic Inflammatory Disease; Pregnancy; Pregnancy Complications, Infectious; Pregnancy, Ectopic
PubMed: 28835360
DOI: 10.1128/CVI.00203-17 -
The Journal of Infectious Diseases Aug 2021Pelvic inflammatory disease (PID) is a syndrome that causes substantial morbidity, including chronic pelvic pain, to women globally. While limited data are available... (Review)
Review
Pelvic inflammatory disease (PID) is a syndrome that causes substantial morbidity, including chronic pelvic pain, to women globally. While limited data are available from low- and middle-income countries, national databases from the United States and Europe suggest that PID incidence may be decreasing but the rate of decrease may differ by the etiologic cause. Recent studies of women with PID have reported that fewer than half of women receiving a diagnosis of PID have gonococcal or chlamydial infection, while Mycoplasma genitalium, respiratory pathogens, and the constellation of bacteria associated with bacterial vaginosis may account for a substantial fraction of PID cases. The clinical diagnosis of PID is nonspecific, creating an urgent need to develop noninvasive tests to diagnose PID. Advances in serologic testing for Chlamydia trachomatis and Neisseria gonorrhoeae could advance epidemiologic studies, while the development of vaccines against these sexually transmitted pathogens could affect incident PID and associated morbidity.
Topics: Chlamydia Infections; Chlamydia trachomatis; Female; Gonorrhea; Humans; Incidence; Neisseria gonorrhoeae; Pelvic Inflammatory Disease; United States
PubMed: 34396398
DOI: 10.1093/infdis/jiab116 -
Frontiers in Public Health 2021infection has been associated with adverse pregnancy and neonatal outcomes such as premature rupture of membranes, preterm birth, low birth weight, conjunctivitis, and... (Review)
Review
infection has been associated with adverse pregnancy and neonatal outcomes such as premature rupture of membranes, preterm birth, low birth weight, conjunctivitis, and pneumonia in infants. This review evaluates existing literature to determine potential benefits of antenatal screening and treatment of in preventing adverse outcomes. A literature search revealed 1824 studies with 156 full-text articles reviewed. Fifteen studies were selected after fulfilling inclusion criteria. Eight studies focused on chlamydial screening and treatment to prevent adverse pregnancy outcomes such as premature rupture of membranes, preterm birth, low birth weight, growth restriction leading to small for gestational age infants, and neonatal death. Seven studies focused on the effects of chlamydial screening and treatment on adverse infant outcomes such as chlamydial infection including positive mucosal cultures, pneumonia, and conjunctivitis. Given the heterogeneity of those studies, this focused review was exclusively qualitative in nature. When viewed collectively, 13 of 15 studies provided some degree of support that antenatal chlamydial screening and treatment interventions may lead to decreased adverse pregnancy and infant outcomes. However, notable limitations of these individual studies also highlight the need for further, updated research in this area, particularly from low and middle-income settings.
Topics: Chlamydia Infections; Chlamydia trachomatis; Female; Humans; Infant, Newborn; Pregnancy; Pregnancy Complications, Infectious; Pregnancy Outcome; Premature Birth
PubMed: 34178906
DOI: 10.3389/fpubh.2021.531073 -
American Family Physician Apr 2022
Topics: Chlamydia; Chlamydia Infections; Chlamydia trachomatis; Humans
PubMed: 35426650
DOI: No ID Found -
Current Topics in Microbiology and... 2018Chlamydial infections lead to a number of clinically relevant diseases and induce significant morbidity in human populations. It is generally understood that certain... (Review)
Review
Chlamydial infections lead to a number of clinically relevant diseases and induce significant morbidity in human populations. It is generally understood that certain components of the host immune response to infection also mediate such disease pathologies. A clear understanding of pathogenic mechanisms will enable us to devise better preventive and/or intervention strategies to mitigate the morbidity caused by these infections. Over the years, numerous studies have been conducted to explore the immunopathogenic mechanisms of Chlamydia-induced diseases of the eye, reproductive tract, respiratory tract, and cardiovascular systems. In this article, we provide an overview of the diseases caused by Chlamydia, animal models used to study disease pathology, and a historical context to the efforts to understand chlamydial pathogenesis. Furthermore, we discuss recent findings regarding pathogenesis, with an emphasis on the role of the adaptive immune response in the development of chlamydial disease sequelae. Finally, we summarize the key insights obtained from studies of chlamydial pathogenesis and avenues that remain to be explored in order to inform the next steps of vaccine development against chlamydial infections.
Topics: Adaptive Immunity; Animals; Chlamydia Infections; Chlamydia trachomatis; Disease Models, Animal; Humans
PubMed: 27370346
DOI: 10.1007/82_2016_18 -
PloS One 2017Chlamydial disease continues to be one of the main factors threatening the long-term survival of the koala (Phascolarctos cinereus). Despite this, large epidemiological...
Chlamydial disease continues to be one of the main factors threatening the long-term survival of the koala (Phascolarctos cinereus). Despite this, large epidemiological studies of chlamydial infection and disease in wild koala populations are lacking. A better understanding of the prevalence, transmission and pathogenesis is needed to improve control measures, such as the development of vaccines. We investigated the prevalence of Chlamydia pecorum infection and disease in 160 koalas in a peri-urban wild population in Queensland, Australia and found that 31% of koalas were Chlamydia PCR positive and 28% had clinically detectable chlamydial disease. Most infections were at the urogenital site (27%; both males and females) with only 14% at the ocular site. Interestingly, we found that 27% (4/15) of koalas considered to be sexually immature (9-13 months) were already infected with C. pecorum, suggesting that a significant percentage of animals are infected directly from their mother. Ocular infection levels were less prevalent with increasing age (8% in koalas older than 4 years), whereas the prevalence of urogenital tract infections remained high into older age (26% in koalas older than 4 years), suggesting that, after mother-to-young transmission, C. pecorum is predominantly a sexually transmitted infection. While 28% of koalas in this population had clinically detectable chlamydial disease (primarily urogenital tract disease), many PCR positive koalas had no detectable disease and importantly, not all diseased animals were PCR positive. We also observed higher chlamydial loads in koalas who were C. pecorum infected without clinical disease than in koalas who were C. pecorum infected with clinical disease. These results shed light on the potential mechanisms of transmission of C. pecorum in koalas and also guide future control measures, such as vaccination.
Topics: Animals; Chlamydia; Chlamydia Infections; Female; Female Urogenital Diseases; Male; Male Urogenital Diseases; Phascolarctidae; Polymerase Chain Reaction; Prevalence; Queensland
PubMed: 29281731
DOI: 10.1371/journal.pone.0190114 -
Deutsches Arzteblatt International Mar 2010Zoonoses were already a subject of intense interest even before the SARS and avian influenza epidemics arose. For many years, chlamydiae have been hypothesized to be... (Review)
Review
BACKGROUND
Zoonoses were already a subject of intense interest even before the SARS and avian influenza epidemics arose. For many years, chlamydiae have been hypothesized to be important zoonotic pathogens, because of their wide distribution and their infectious cycle. This article provides an overview of the current state of knowledge on this subject.
METHODS
The authors present a selective review of the literature as well as their own findings.
RESULTS
The scientific knowledge of the distribution and infectious cycle of chlamydiae is still inadequate. The laboratory diagnosis of chlamydial zoonoses remains unsatisfactory in both human and veterinary medicine, as there are no commercially available sensitive and species-specific tests. Acute chlamydial infections are usually treated with macrolides, tetracyclines, or quinolones. Persistent varieties are not covered by standard therapy.
CONCLUSIONS
There is a considerable need for research on chlamydial infections, especially with regard to the diagnosis and treatment of persistent varieties.
Topics: Animal Husbandry; Animals; Animals, Domestic; Bird Diseases; Birds; Cattle; Cattle Diseases; Chlamydia; Chlamydia Infections; Chronic Disease; Diagnosis, Differential; Humans; Oligonucleotide Array Sequence Analysis; Poultry Diseases; Psittacosis; Risk Factors; Sensitivity and Specificity; Species Specificity; Swine; Swine Diseases; Zoonoses
PubMed: 20358033
DOI: 10.3238/arztebl.2010.0174 -
American Family Physician Apr 2022Infections caused by Chlamydia trachomatis and Neisseria gonorrhoeae are increasing in the United States. Because most infections are asymptomatic, screening is key to...
Infections caused by Chlamydia trachomatis and Neisseria gonorrhoeae are increasing in the United States. Because most infections are asymptomatic, screening is key to preventing complications such as pelvic inflammatory disease and infertility and decreasing community and vertical neonatal transmission. All sexually active people with a cervix who are younger than 25 years and older people with a cervix who have risk factors should be screened annually for chlamydial and gonococcal infections. Sexually active men who have sex with men should be screened at least annually. Physicians should obtain a sexual history free from assumptions about sex partners or practices. Acceptable specimen types for testing include vaginal, endocervical, rectal, pharyngeal, and urethral swabs, and first-stream urine samples. Uncomplicated gonococcal infection should be treated with a single 500-mg dose of intramuscular ceftriaxone in people weighing less than 331 lb (150 kg). Preferred chlamydia treatment is a seven-day course of doxycycline, 100 mg taken by mouth twice per day. All nonpregnant people should be tested for reinfection approximately three months after treatment or at the first visit in the 12 months after treatment. Pregnant patients diagnosed with chlamydia or gonorrhea should have a test of cure four weeks after treatment.
Topics: Aged; Chlamydia Infections; Chlamydia trachomatis; Female; Gonorrhea; Homosexuality, Male; Humans; Infant, Newborn; Male; Neisseria gonorrhoeae; Pregnancy; Sexual and Gender Minorities; United States
PubMed: 35426632
DOI: No ID Found