Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Chlamydia trachomatis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1990

Detection and differentiation of Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae by DNA amplification.

The polymerase chain reaction was used to detect major outer membrane protein (MOMP) gene sequences from the three species of Chlamydia. Using three primer pairs and one restriction enzyme digestion, three distinct genotypes, corresponding to the three species, Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci, were demonstrated. C. trachomatis was amplified by all three primer pairs and the amplified fragment was digested by EcoRI. C. pneumoniae was amplified by only two of the three primer pairs, and the amplified fragment was digested by EcoRI. C. psittaci was amplified by only two of the pairs and the amplified fragment was EcoRI-resistant. C. trachomatis was detected in direct patient specimens, tissue culture specimens, and fixed specimens, and all serovars of C. trachomatis were detectable. The polymerase chain reaction can detect and differentiate the three species of Chlamydia and may prove a valuable diagnostic tool.

Bacterial Outer Membrane Proteins↗
PubMedDate not supplied

Detection of IgM antibodies to Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci from Japanese infants and children with pneumonia.

Chlamydia trachomatis (C. trachomatis) is now well established as a pathogen of neonatal inclusion conjunctivitis and infantile pneumonia. C. pneumoniae (TWAR) and C. psittaci also cause pneumonia and other respiratory infections. Serum samples from 223 Japanese infants and children with pneumonia were tested for IgM antibodies to C. trachomatis, C. pneumoniae and C. psittaci. IgM antibodies to C. trachomatis were measured by an enzyme immunoassay (EIA) and by a microimmunofluorescence (MIF) test. IgM antibodies to C. pneumoniae and C. psittaci were determined by MIF. Of 223 patients, 48 (21.5%) were positive for IgM antibodies to C. trachomatis, 11 (4.9%) were positive for C. pneumoniae and 5 (2.2%) were positive for C. psittaci. From nasopharyngeal swabs collected from 87 infants with pneumonia (0 to 1 year of age), we attempted to isolate C. trachomatis with tissue culture. C. trachomatis was isolated from 23 (26.4%) of 87 infants with pneumonia, and IgM antibodies to C. trachomatis were detected in 17 (19.5%) of them. Our data suggest a role for chlamydial infection in childhood pneumonia beyond infancy with both C. trachomatis and C. pneumoniae being contributing pathogens.

Adolescent↗
PubMed1994

Immunoreactivity of the 60 kDa cysteine-rich proteins of Chlamydia trachomatis, Chlamydia psittaci and Chlamydia pneumoniae expressed in Escherichia coli.

The 60 kDa cysteine-rich proteins (CrPs) of Chlamydia are developmentally regulated outer envelope proteins synthesized late in the chlamydial growth cycle. These proteins, found only on the extracellular infectious elementary bodies, elicit major antibody responses in chlamydial infection. We have cloned and expressed in Escherichia coli the complete 60 kDa CrP genes from Chlamydia trachomatis, C. psittaci and C. pneumoniae. The recombinant products were expressed as either 'native' proteins or as fusions with the bacteriophage T7 gene 10 protein. Electron microscopy showed that recombinant proteins were produced as insoluble inclusions within the E. coli host cells. The recombinant 60 kDa CrPs were purified and used to raise high titre polyclonal antisera. In immunoblot analysis these antisera reacted with the 60 kDa CrPs from purified elementary bodies of all three chlamydial species in a genus-specific manner. Further molecular analysis allowed the genus-specific cross-reacting epitopes to be localized by using overlapping synthetic peptides covering the C. trachomatis 60 kDa CrP. Immunogold labelling experiments, using purified infectious elementary bodies from the three chlamydial species indicated that the 60 kDa CrPs are not surface accessible to antibody binding.

Amino Acid Sequence↗
PubMed1996

Prevalence of Chlamydia trachomatis, Chlamydia psittaci and Chlamydia pneumoniae antibodies in blood donors and attendees of STD clinics.

OBJECTIVE: To estimate the prevalence of Chlamydia trachomatis, C. psittaci and C. pneumoniae antibodies in sera from altogether 931 blood donors, patients with symptoms of urethritis, assumed salpingitis and sexually acquired reactive arthritis (SARA), and women with fertility problems. METHODS: IgG antibodies to C. trachomatis, C. psittaci and C. pneumoniae were determined by microimmunofluorescence (MIF) tests. All patients were also tested for genital C. trachomatis infection using direct immunofluorescence (DIF) tests. RESULTS: The DIF-positive cases had a significantly (p < 0.0001) higher prevalence of C. trachomatis antibodies than the DIF negatives, i.e. 88.5% versus 14% in men with urethritis, 94.3% versus 36.4% in women with salpingitis, 66.7% versus 16.7% in SARA patients and 90.6% versus 20.8% in women with fertility problems. Antibody reactivity to all three chlamydial species was found significantly (p < 0.0001) more often in the patient groups and in those with a DIF-confirmed genital C. trachomatis infection than in blood donors. CONCLUSIONS: Presence of serum antibodies to C. trachomatis is tightly associated with the presence of chlamydiae in the genital tract, which also influences the cross-reactivities occurring in the MIF tests between chlamydial species.

Journal Article↗
PubMed2001

Acute and chronic urinary tract infections caused by Chlamydia trachomatis.

Chlamydia trachomatis is one of the causes of acute and chronic urinary tract infections and acute or silent salpingitis. Chronic or recurrent female urinary or genital tract infections with Chlamydia trachomatis have been recognised as a significant factor in the development of acute or chronic renal interstitial inflammation or increased risk of ectopic pregnancy. In most cases Chlamydia trachomatis is sexually transmitted. Moreover, it is one of the most common sexually transmitted pathogens. The current estimate is that in the United States there occur 4.5 million new infections each year. We describe 3 cases of recurrent urinary tract infections due to Chlamydia trachomatis.

Acute Disease↗
PubMedDate not supplied

Antigens of Chlamydia trachomatis.

Chlamydia trachomatis is an obligate intracellular parasite that elaborates antigens on its surface. These antigens are divided into genus-, species-, subspecies-, and serovar-specific determinants. The genus, or group antigen(s), are lipopolysaccharides similar to those found in gram-negative bacteria and a glycolipid that is secreted by infected cell cultures. Species-specific antigens differentiate Chlamydia trachomatis from Chlamydia psittaci and are expressed on the outer membrane. These proteins range in molecular weight from 155,000 to approximately 40,000. Monoclonal antibodies to outer-membrane proteins have demonstrated the presence of subspecies-reactive antigenic determinants. Type-specific antigens are associated with the major outer-membrane protein and are secreted from infected cells as well. The molecular weights of these proteins range from 30,000 to 40,000. These antigens may participate in the binding of the organism to target cells and in an enzymatic process of some type that initiates endocytosis. The significance of the soluble antigens detected in the microenvironment in vitro may suggest immune-complex formation, a process that could contribute to the immunopathology of the disease.

Antigens, Bacterial↗
PubMed2000

Update on Chlamydia trachomatis.

Chlamydia trachomatis is one the most important sexually transmitted diseases; it can cause serious sequelae despite the absence of symptoms in some people. It's estimated that about 25% of women who have acute salpingitis become infertile, and chlamydial infection is the commonest cause. The introduction of screening programs for its detection are still a topic of discussion. The literature shows that the total cost of examination and treatment of complications known to be associated with genital chlamydial infection (PID, chronic pelvic pain, tubal factor infertility) is generally higher than the total cost of a large-scale Chlamydia screening program. The selection of a diagnostic test for detection of chlamydial genital infection depends on availability, local expertise, and prevalence of Chlamydia trachomatis in the test population. Cell culture is too expensive in nonendemic regions, so the use of non-culture techniques is very attractive. PCR (polymerase chain reaction) and LCR (ligase chain reaction) are actually the two most commonly used alternatives to conventional methods for detecting STD agents. In fact, PCR and LCR have proved useful for detection of Chlamydia trachomatis in cervical and urethral samples both in symptomatic and asymptomatic women. Recently, testing of first-void urine (FVU) specimens with these techniques has shown that the amplification tests are as sensitive as tests with endocervical swab cultures.

Animals↗
PubMed2003

A mathematical model for the investigation of the Th1 immune response to Chlamydia trachomatis.

Chlamydia are bacterial pathogens of humans and animals causing the important human diseases trachoma, sexually transmitted chlamydial disease and pneumonia. Of the human chlamydial diseases, sexually transmitted disease caused by Chlamydia trachomatis is a major public health concern. Chlamydia trachomatis replicates intracellularly and is characterised by a complex developmental cycle. Chlamydia is susceptible to humoral and cell-mediated immunity. Here we investigate the Th1 cell-mediated immune response against Chlamydia-infected cells as the response changes over the chlamydial developmental cycle. We suggest a form for the immune response over one developmental cycle by modelling the change in the number of intracellular chlamydial particles and assume peptides are presented in proportion to the number of replicating forms of chlamydial particles. We predict, perhaps non-intuitively, that persistent Chlamydia should be induced and forced not to return to the lytic cycle. We also suggest that extending the length of the time of the lytic cycle will effectively decrease the required efficacy of the Th1 response to eliminate the pathogen. We produce plots of active disease progression, control and clearance for varying levels of Th1 effectiveness.

Chlamydia Infections↗
PubMed1989

[Inflammation of the female genital organs caused by Chlamydia trachomatis].

Chlamydia trachomatis has been presented in a growing number of recent papers as a causative agent of diseases such as cervicitis, endometritis, salpingitis and peritonitis. Based on the results available in literature, significance of an early detection of female genital tract inflammations caused by Chlamydia trachomatis because of its often asymptomatic flow, irreparable sequels of uncured inflammation and possible curing with tetracyclines and macrolides therapy has been discussed.

Chlamydia Infections↗
PubMed2006

Novel overlapping coding sequences in Chlamydia trachomatis.

Chlamydia trachomatis is the aetiological agent of trachoma and sexually transmitted infections. The C. trachomatis genome sequence revealed an organism adapted to the intracellular habitat with a high coding ratio and a small genome consisting of 1.042-kilobase (kb) with 895 annotated protein coding genes. Here, we repredict the protein-coding genes of the C. trachomatis genome using the gene-finder EasyGene that was trained specifically for C. trachomatis, and compare it with the primary C. trachomatis annotation. Our work predicts 15 genes not listed in the primary annotation and 853 that are in agreement with the primary annotation. Forty two genes from the primary annotation are not predicted by EasyGene. The majority of these genes are listed as hypothetical in the primary annotation. The 15 novel predicted genes all overlap with genes on the complementary strand. We find homologues of several of the novel genes in C. trachomatis Serovar A and Chlamydia muridarum. Several of the genes have typical gene-like and protein-like features. Furthermore, we confirm transcriptional activity from 10 of the putative genes. The combined evidence suggests that at least seven of the 15 are protein coding genes. The data suggest the presence of overlapping active genes in C. trachomatis.

Chlamydia trachomatis↗
PubMed1979

[The replication cycle of Chlamydia trachomatis and Chlamydia psittaci: ultrastructural analysis].

An ultrastructural comparative analysis is reported on the replication cycle of six strains of Chlamydia trachomatis, recently isolated, and Chlamydia psittaci strain 6BC, grown in cell cultures. Important morphological distinctions of the bacterial walls are documented. In Chlamydia trachomatis the cell wall seems more rigid. This causes, during the morphogenesis of the elementary body, its separation from the cell membrane with formation of an electron transparent space, which is not demonstrable in Chlamydia psittaci. As a result of this process, the appearance of "ghosts" and "mini reticular bodies" is documented. Budding and multiple fission are suggested as possible mechanisms of replication of Chlamydia trachomatis, in coexistence or/as alternative to binary fission.

Cell Wall↗
PubMed1991

The value of urine samples from men with non-gonococcal urethritis for the detection of Chlamydia trachomatis.

Chlamydia trachomatis was sought at first and subsequent clinic visits in urethral swabs and urines from 112 heterosexual men with acute non-gonococcal urethritis (NGU). In comparison with a urethral swab tested by Micro Trak (MT), a urine deposit tested in the same way was 90% as sensitive. Examining a urine deposit by the enzyme immunoassay IDEIA was a little less sensitive (89%) than examining a similar deposit by MT, and was less sensitive (82%) than examining a urethral swab by MT. The results of testing urines were little influenced by collecting them either before or after swabbing the urethra, and there was evidence that examining all of a urine sample by IDEIA would have increased sensitivity. Overall, 55 (49%) of the men were diagnosed as C trachomatis-positive based on the results of testing both a urethral swab and a urine sample. Furthermore, a small numbers of chlamydiae were detected by examining urine by MT and, to a lesser extent, by IDEIA, so that there is no reason why this non-invasive approach should not be successful in men other than those with acute NGU.

Chlamydia Infections↗
PubMed2005

Vaccination of newborn mice induces a strong protective immune response against respiratory and genital challenges with Chlamydia trachomatis.

Chlamydia trachomatis infections can occur early in life and may result in long-term sequelae. To assess the feasibility of implementing a vaccine in newborns, groups of 2-day-old BALB/c mice were immunized intranasally (i.n.) with 1x10(4) inclusion forming units (IFU) of C. trachomatis mouse pneumonitis (MoPn). As a control, newborn mice were sham-immunized i.n. with minimal essential medium. In the vaccinated animals, strong Chlamydia-specific humoral and cell-mediated immune responses were observed. Six weeks after immunization, mice were challenged with MoPn i.n. or intravaginally (i.vag.). For the i.n. challenge, mice were inoculated with 10(4) or 10(5)IFU of MoPn per mouse, and in the case of the i.vag. challenge, each animal received 10(6)IFU. By day 10 post-infection (p.i.), the vaccinated mice challenged i.n. with 10(4)IFU, had gained an average of 6.7+/-1% of their body weight. In contrast, the sham-immunized mice had lost 14.9+/-1% of their weight (P<0.05). The mean number of IFU/lungs in the vaccinated animals was 800+/-300, while for the sham-immunized mice was 211+/-49x10(6) (P<0.05). Significant differences between the Chlamydia-vaccinated and the sham-immunized mice were also found in the groups challenged with 10(5)IFU. In the mice challenged i.vag., a significant decrease in the number of mice with positive cultures, and the intensity and duration of vaginal shedding was noted in the vaccinated mice compared to the sham-immunized mice (P<0.05). In conclusion, these results indicate that vaccination of neonatal mice can result in a protective response against a subsequent pulmonary or genital challenge with Chlamydia.

Animals↗
PubMed1980

Colonisation of pregnant and puerperal women and neonates with Chlamydia trachomatis.

Chlamydia trachomatis was cultured from cervical specimens of 14 (16.1%) of 231 women applying for legal abortion and from 23 (8.7%) of 273 puerperal women. The chlamydial isolation rate was related to the women's age. Of the pregnant and puerperal women under 20 years C trachomatis was isolated in 10% and 24% respectively; in those aged between 20 and 24 years the rates were 8.7% and 10.2% respectively whereas in those over 24 years the rates were 4.2% in both groups. Chlamydia were isolated more frequently from cervical specimens than from urethral specimens. However, if a cervical specimen alone had been examined the diagnosis would have been missed in three (17%) of 18 women. IgG antichlamydial antibodies (titre greater than or equal to 1/32) were detected by a micro-immunofluorescence test in samples of cord blood from 35 (25%) of 139 infants of the puerperal women. Of the 23 infants born to mothers harbouring chlamydia in the cervix C trachomatis was isolated from the conjuntival folds in five (22.5%). The chlamydial isolation rate from the eyes of the neonates was related to the time of sampling. None of the 108 infants examined between 6 and 7 days old was chlamydia-positive whereas chlamydia could be recovered from the conjunctival folds of four of them when re-examined from three to 23 days later.

Adult↗
PubMed2025

A platform supporting generation and isolation of random transposon mutants in Chlamydia trachomatis.

Chlamydia species represent a paradigm for understanding successful obligate intracellular parasitism. Despite limited genetic malleability, development of genetic tools has facilitated the elucidation of molecular mechanisms governing infectivity. Random mutagenesis approaches provide one of the most powerful strategies available to accomplish untargeted elucidation of gene function. Unfortunately, initial progress in transposon-mediated mutagenesis of Chlamydia has been challenging. To increase efficiency, we developed a plasmid-based system that couples conditional plasmid maintenance with a previously described strategy leveraging inducible expression of the Himar1-derived C9 transposase. Our pOri-Tn(Q) construct was maintained in Chlamydia trachomatis cultivated with antibiotics but was rapidly cured in the absence of antibiotic selection. pOri-Tn(Q) supported transposition events when transposase expression was induced during infection. Induction was accompanied by loss of the plasmid backbone when penicillin G was used to select for only the transposable element. C9 induction during iterative passaging was used to increase the overall insertion frequency and accumulate an expanded pool of transposon mutants. The approach supported isolation of individual mutant strains from the mixed pool, and whole-genome sequencing confirmed that the recovered strains harbored single insertions.IMPORTANCEChlamydia trachomatis is a prevalent human pathogen exerting a tremendous negative impact on human health. A complete understanding of how these bacteria create and maintain an intracellular niche and avoid/subvert host defense mechanisms to cause disease is lacking. The utility of transposon-mediated, random mutagenesis in supporting forward genetic studies is well established in a multitude of genetically tractable systems. This study reports the development of a plasmid-based system capable of generating mutant pools and supporting subsequent isolation of individual transposon mutants. This step is an important advance in providing a mechanism capable of supporting downstream studies interrogating chlamydial biology.

Chlamydia trachomatis↗
PubMed2006

IL-10 polymorphism and cell-mediated immune response to Chlamydia trachomatis.

Chlamydia trachomatis infection induces an inflammatory response that is crucial in resolving acute infection but may also play a key role in the pathogenesis of C trachomatis associated infertility. The immune response is linked to cytokine secretion pattern which is influenced by the host genetic background. To study a relationship between interleukin-10 (IL-10) promoter -1082 polymorphism and cell-mediated immune response during C trachomatis infection in vitro, lymphocyte proliferation and cytokine (IL-10, IFN-gamma, TNF-alpha, IL-2, IL-4 and IL-5) secretion were analysed in subjects with different IL-10 genotypes. Enhanced IL-10 secretion and reduced antigen-specific lymphocyte proliferative and IFN-gamma responses were found in subjects with IL-10 -1082 GG genotype when compared to those with -1082 AA genotype. CD14+ monocytes were main source of IL-10 indicating that these cells are important regulators of the antigen-specific cell-mediated responses during active C trachomatis infection. We conclude that impaired cell-mediated response to C trachomatis is associated with IL-10 genotype in subjects with high IL-10 producing capacity. A comparison of immune markers between subjects with a history of noncomplicated and complicated infection is needed to further understand the confounding factors associated with the development of C trachomatis associated sequelae.

Adolescent↗
PubMed2006

Core of the partner switching signalling mechanism is conserved in the obligate intracellular pathogen Chlamydia trachomatis.

Chlamydia trachomatis is an obligate intracellular bacterial pathogen that can cause sexually transmitted and ocular diseases in humans. Its biphasic developmental cycle and ability to evade host-cell defences suggest that the organism responds to external signals, but its genome encodes few recognized signalling pathways. One such pathway is predicted to function by a partner switching mechanism, in which key protein interactions are controlled by serine phosphorylation. From genome analysis this mechanism is both ancient and widespread among eubacteria, but it has been experimentally characterized in only a few. C. trachomatis has no system of genetic exchange, so here an in vitro approach was used to establish the activities and interactions of the inferred partner switching components: the RsbW switch protein/kinase and its RsbV antagonists. The C. trachomatis genome encodes two RsbV paralogs, RsbV(1) and RsbV(2). We found that each RsbV protein was specifically phosphorylated by RsbW, and tandem mass spectrometry located the phosphoryl group on a conserved serine residue. Mutant RsbV(1) and RsbV(2) proteins in which this conserved serine was changed to alanine could activate the yeast two-hybrid system when paired with RsbW, whereas mutant proteins bearing a charged aspartate failed to activate. From this we infer that the phosphorylation state of RsbV(1) and RsbV(2) controls their interaction with RsbW in vivo. This experimental demonstration that the core of the partner switching mechanism is conserved in C. trachomatis indicates that its basic features are maintained over a large evolutionary span. Although the molecular target of the C. trachomatis switch remains to be identified, based on the predicted properties of its input phosphatases we propose that the pathway controls an important aspect of the developmental cycle within the host, in response to signals external to the C. trachomatis cytoplasmic membrane.

Amino Acid Sequence↗
PubMed1985

Recent advances in Chlamydia trachomatis.

Chlamydia trachomatis is an obligate intracellular energy parasitic bacterium with a genome of 660 X 10(6) daltons, possessing a plasmid and unique life cycle which includes the differentiation of the infective elementary body to a replicative reticulate body. C. trachomatis is the etiological agent of trachoma, which affects approximately 500 million people in developing countries. Recently it became evident that in industrialised Western nations certain strains of C. trachomatis are the most common cause of sexually transmitted infections such as non-gonococcal urethritis, cervicitis, endometritis, salpingitis and subsequent ectopic pregnancies or infertility, perihepatitis, neonatal conjunctivitis and pneumonia, adult conjunctivitis and epididymitis. Since C. trachomatis infections are often asymptomatic, widespread screening of sexually active young people is needed in order to initiate early antibiotic treatment which may prevent serious complications such as ectopic pregnancies and infertility. Development of sensitive and simple techniques for mass screening for detection of Chlamydia in excretions as well as techniques for detection of specific markers of chronic internal infections (such as Chlamydia specific IgA antibodies) is of great importance.

Chlamydia Infections↗