Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Chlamydia”

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 1,225 records · Page 68Linked to original sources
PubMed2005

Modelling the impact of opportunistic screening on the sequelae and public healthcare costs of infection with Chlamydia trachomatis in Australian women.

OBJECTIVES: To describe the health outcomes and public healthcare costs of a single screening for Chlamydia trachomatis in Australian women aged 15-34 years. METHODS: A decision analytic model was used to determine the epidemiological estimates of prevalence and costs of C. trachomatis infection and its diagnosis, treatment and sequelae. RESULTS: We estimate that in any female population in Australia, with a Chlamydia prevalence rate of 5.7% or higher, a single screening examination for Chlamydia is cost saving for the public healthcare system. CONCLUSIONS: We found that opportunistic screening of high-risk populations is likely to be cost saving to the public healthcare system, although there is not sufficient evidence to support periodic population screening. As our model uses conservative epidemiological and public healthcare cost estimates, the health and financial impacts of C. trachomatis used in the model may be an underestimate of the true costs of infection.

Adolescent↗
PubMed2005

Immunization with the Chlamydia trachomatis major outer membrane protein, using adjuvants developed for human vaccines, can induce partial protection in a mouse model against a genital challenge.

To test several vaccines for Chlamydia trachomatis we vaccinated BALB/c and C3H/HeN female mice with a purified preparation of the native mouse pneumonitis (MoPn) major outer membrane protein (MOMP). The MOMP was formulated with anyone of three different adjuvants MF59, LT-K63 or LT-R72. As a negative control the animals were immunized with ovalbumin. Positive controls were inoculated intranasally (i.n.) with 10(4) inclusion-forming units (IFU) of C. trachomatis MoPn. High levels of Chlamydia-specific antibodies were detected in the serum and vaginal washes of the mice immunized with MOMP. Using a lymphoproliferative assay (LPA) a significant response was obtained in splenocytes from most of the groups of mice vaccinated with MOMP. Two weeks after the last immunization the mice were challenged in the left ovarian bursa with 10(5) IFU of C. trachomatis MoPn and vaginal cultures were collected for a period of 6 weeks. Overall, BALB/c and C3H/HeN mice immunized with MOMP showed a decrease in the severity and length of the infection but the difference with the controls was not statistically significant. Following mating the percentage of mice with bilateral fertility was not significantly different between mice vaccinated with MOMP and their respective ovalbumin-immunized controls. However, the C3H/HeN mice immunized with MOMP using MF59 or LTR72 as adjuvants had significantly more embryos per mouse than the control groups. In conclusion, mice immunized with native MOMP and adjuvants developed for human vaccines showed significant Chlamydia-specific immune response and a limited protection against infection and long-term sequelae.

Animals↗
PubMed2005

Mucosal immunization with recombinant MOMP genetically linked with modified cholera toxin confers protection against Chlamydia trachomatis infection.

Chlamydia trachomatis is a major human health pathogen due to its role in sexually transmitted diseases. Thus, there is a need to develop an effective vaccine at the mucosal surface against this pathogen. In an effort to develop a mucosal vaccine, a modified cholera toxin gene was genetically linked to the C. trachomatis MoPn NiggII MOMP gene to generate a recombinant protein with the mucosal adjuvant properties of the cholera toxin and immunological antigenicity of the chlamydial protein. The recombinant fusion protein (rMOMP) was expressed in E. coli, purified and analyzed by SDS-PAGE, immunoblot, and GM1-ELISA, and subsequently used to immunize BALB/c mice via intranasal (i.n.) and intravaginal (vag.) routes. The rMOMP protein administered via the i.n. route induced a higher concentration of anti-MOMP specific antibodies in both serum and vaginal washes as compared to mice immunized with Chlamydia or PBS. Antibody isotype analysis revealed that i.n. administration of rMOMP to mice induced higher concentrations of serum and vaginal wash IgA, IgG1, IgG2a, and IgG2b antibodies. Vaginal washes from all immunized mice following a chlamydial challenge infection were analyzed by indirect immunoflourescence to study the level of protection provided by various immunogens. Maximum protection against C. trachomatis as assessed by reduction in C. trachomatis inclusion forming units (IFU) was provided by i.n. immunization of mice with rMOMP. This is a first report using genetic fusion of cholera toxin and MOMP genes and provides a novel approach for the design and development of a mucosal vaccine against Chlamydia.

Administration, Intranasal↗
PubMed2002

Screening for Chlamydia trachomatis infection is indicated for women under 30 using emergency contraception.

A total of 838 women attending a large family planning clinic in Scotland for emergency contraception were offered screening for Chlamydia trachomatis infection. 569 were screened using ligase chain reaction test in first void urine at the time of presenting for emergency contraception and were retested 1 or 2 weeks later. Women aged under 20 and over 30 years were significantly more likely to decline to be tested than women aged 20 to 30. The prevalence of chlamydia was 7.6% in woman aged 24 or less, 5.3% in women aged 25 to 29, and 1.2% in women aged 30 or more. Only two women (< 1%) who tested negative at the time of using EC were positive 1 or 2 weeks later. Women under age 30 who use EC should be offered screening for chlamydia infection and testing at the time they attend for EC is adequate to detect the great majority of infected women.

Adolescent↗
PubMed2003

Effect of treatment for Chlamydia trachomatis during pregnancy.

OBJECTIVES: To screen and treat chlamydial infection in pregnant women in order to assess the effects of therapeutic intervention on the outcome of Chlamydia trachomatis-infected pregnancy. METHODS: Enrolled in the study were 350 women in the first to third trimesters of pregnancy. Endocervical swabs were collected for C. trachomatis diagnosis by DFA and PCR. A few STD infections, viz.: Neisseria gonorrhoeae, Candida spp., bacterial vaginosis, Trichomonas vaginalis and Treponema pallidum were ruled out. After excluding 22 patients infected with other sexually transmitted infections, a cohort of 328 pregnant women comprised the study population. Anti-chlamydial treatment (viz.: oral therapy with erythromycin stearate, 500 mg 4 times daily for 7 days) was given to 17 women (group I) and their partners. Fifteen patients of group I were retested by DFA and PCR assay for C. trachomatis infection 2 weeks following therapy. Other Chlamydia-positive patients (n=42) who were lost to follow-up were classified as untreated positive cases (group II) while group III included C. trachomatis negative cases (n=269). Data on obstetric outcome were recorded in a total of 164 cases. Statistical comparison of the data were done using the chi(2)-test and means were compared using Student's t-test. RESULTS: Among the 350 pregnant women enrolled initially for the study, C. trachomatis positivity was found to be 18.8% (n=66) in the endocervix by DFA and PCR assay. Co-infection with Candida spp., bacterial vaginosis, T. vaginalis and T. pallidum was 2.0%, 1.7%, 1.7% and 0.5%, respectively. None of the pregnant women was infected with N. gonorrhoeae. Pregnant women at an increased risk of chlamydial infection included those who had multiple births and were in second trimester of pregnancy. Fifteen patients of group I became Chlamydia-negative following treatment. Data on obstetric outcome were recorded in 11, 26 and 127 patients of groups I, II and III, respectively. The mean duration of gestation for premature deliveries was found to be significantly higher in group I in comparison with group II [35.5 vs. 33.1 weeks (P<0.05)], thereby showing an improved effect of treatment on pregnancy outcome. The mean of low birth weight births was higher in group I compared with group II (2200.0 vs. 2113.3 g), however, this was statistically non-significant. Stillbirths were significantly higher among group II in comparison with group III [11.5% vs. 4.7% (chi(2)=1.79; P<0.5)]. No stillbirths were recorded in patients who had taken anti-chlamydial treatment. CONCLUSIONS: Our findings suggest that routine screening and treatment of C. trachomatis infection in pregnant women, especially those in high risk groups, should be mandatory to reduce the adverse effects on obstetric outcome.

Adult↗
PubMed1984

Ultrastructure of Chlamydia trachomatis infection of the mouse oviduct.

Chlamydial inclusions were found in the luminal epithelium of all segments of the oviducts (ostium, ampulla, and isthmus) of mice experimentally inoculated with the mouse pneumonitis (MoPn) biovar of Chlamydia trachomatis. Electron microscopy of infected oviducts revealed chlamydial inclusions in both ciliated and nonciliated cells of the oviduct epithelium. Inclusions contained typical elementary, intermediate and reticulate bodies as well as numerous "miniature reticulate bodies" and membrane ghosts. Small, vesicle-like structures were observed in infected cells near inclusions but were not seen in apparently uninfected cells nor in the oviducts of mice inoculated with the control (sterile tissue culture supernate) suspension. Chlamydia-like particles were seen in vacuoles of polymorphonuclear leukocytes. Intracellular Chlamydia-like particles were not seen in any other cell type in the mouse oviduct. Infection of the mouse oviduct with MoPn is a convenient model for the study of C. trachomatis morphology in vivo.

Animals↗
PubMed1981

The role of chlamydiae in genitourinary disease.

The incidence of chlamydial organisms in early morning urine specimens obtained from 53 men and 50 women without evidence of urinary tract pathology was 2 per cent in both groups. Early morning urine specimens and/or prostatic fluid or semen was examined in 50 patients with chronic prostatitis and 39 (56 per cent) yielded this organism. Of 31 patients with epididymo-orchitis the early morning urine specimens yielded chlamydiae in 12 (39 per cent) and in those with the acute form of disease the incidence was 56 per cent. The chlamydia recovery rate was 27 per cent in 119 women with cystourethritis. Within these groups of patients approximately 50 per cent of sexual partners had urine cultures positive for chlamydia. The importance of reinfection and the need for careful treatment of patients and consort should be stressed. An appropriate transport medium is necessary for specimen collection and adequate culture facilities are required to achieve effective chlamydial recovery. Trimethoprim-sulfamethoxazole and tetracycline were used effectively in the study for primary and secondary drug therapy.

Adolescent↗
PubMed2000

Human leukocyte antigen class II DQ alleles associated with Chlamydia trachomatis tubal infertility.

OBJECTIVE: To investigate epidemiologic tubal infertility risk factors and the relationship between HLA class II alleles and Chlamydia trachomatis tubal infertility. METHODS: Forty-seven women with tubal infertility and 46 fertile controls were studied in Nairobi, Kenya. A questionnaire was administered and serum collected for measurement of C trachomatis antibodies. HLA class II molecular typing was done with DNA extracted from peripheral blood lymphocytes. The prevalence of C trachomatis microimmunofluorescence antibody, chlamydia heat shock protein 60 antibody, and HLA class II alleles was compared among cases of tubal infertility and fertile controls. RESULTS: Women with tubal infertility more often had histories of pelvic inflammatory disease (15% versus 0%; odds ratio [OR] 16; 95% confidence interval [CI] 5.5, 47) histories of spontaneous abortion (34% versus 7%; OR 6.7; 95% CI 2.8, 16), and antibodies to C trachomatis (53% versus 26%; OR 3.2; 95% CI 1.3, 7.7) than controls. Among infertile women, DQA*0101 and DQB*0501 alleles were positively associated with C trachomatis tubal infertility (OR 4.9; 95% CI 1.3, 18.6, and OR 6.8; 95% CI 1.6, 29.2, respectively). DQA*0102 was negatively associated with C trachomatis tubal infertility (OR 0.2; 95% CI 0.005, 0.6). CONCLUSION: Chlamydia trachomatis infection is an important cause of tubal infertility in Nairobi. The association of specific HLA class II alleles with C trachomatis microimmunofluorescence seropositivity among women with tubal infertility suggests that the DQ locus might modify susceptibility to and pathogenicity of C trachomatis infection.

Adult↗
PubMed1998

Ultrastructure of the murine cervix following infection with Chlamydia trachomatis.

We have used electron microscopy to follow the course of Chlamydia trachomatis infection in the mouse cervix. Although numerous elementary bodies (EBs) were observed on the surface of epithelial cells, evidence of coated pits or entry of EBs into epithelial cells were rarely observed. After 2 days postinoculation, inclusions contained numerous reticulate bodies (RBs) and a few intermediate forms (IBs). At 4 days postinoculation, microvilli were no longer present on infected cells and inclusions had often ruptured and released chlamydiae into the cytoplasm of the cells. Aberrant and miniature RBs, similar to those which have been described in in vitro models for persistence, were observed. Unlike the case in vitro where inclusion cause rupture of the cell, infection in vivo may result in rupture of inclusions within the cytoplasm of infected cells. Our observations also suggest that persistent chlamydia can form in some of the cells of the cervical epithelium that are infected by the initial inoculation.

Animals↗
PubMed1997

Chlamydia psittaci infection in sheep: a paradigm for human reproductive tract infection.

Chlamydiae are important reproductive tract pathogens in a wide variety of animals. In humans, chronic or repeated infection of the female genital tract with Chlamydia trachomatis has been identified as a significant factor in the development of occlusive infertility or increased risk of ectopic pregnancy. The spectrum of reproductive disease recognized in sheep to be caused by Chlamydia psittaci has been primarily restricted to pregnant animals because the organism was clearly identified as a major cause of infectious abortion. However, following pregnancy failure, a chronic chlamydial infection can become established in the reproductive tracts of experimentally infected ewes. Persistent infection of the ewe's reproductive tract may eventually result in pathology, similar to that observed in women infected with C. trachomatis, thus decreasing the breeding life of affected ewes. Furthermore, ewes that experienced C. psittaci induced abortion provide a unique opportunity to study the host: parasite dynamic as it relates to persistent infection. This natural model of persistent infection may, in some ways, be superior to more contrived models in which the chlamydial isolate is not a normal reproductive pathogen of the study animal. Thus, the study of persistent chlamydial infection in sheep may be used for the benefit of both human and veterinary medicine.

Abortion, Veterinary↗
PubMed1999

Criteria for selective screening of cervical Chlamydia trachomatis infection in women attending private gynecology practices.

OBJECTIVE: To develop a screening strategy for Chlamydia trachomatis in private gynecology practices. STUDY DESIGN: Forty-six gynecologists in the greater Paris area systematically screened all consecutive female attenders during one week. Endocervical swabs were tested by enzyme immunoassay, and, if positive, was further confirmed by direct fluorescent antibody test. RESULTS: Overall (out of 1893 women tested), the chlamydia prevalence was 0.8% (95% confidence interval: 0.32-1.2%). Among women younger than 21 years, the prevalence was 5.2% (95%, CI 0.8-9.6). Having had a new sexual partner in the last year was associated with chlamydial infection, independent of age. However, half of the infected women had not had a new partner. CONCLUSION: Even in this low risk population, the prevalence was high among young women. Most of these infections would probably not have been detected. We developed a strategy which would have detected 81% of chlamydia positive women by testing only one third of the patients.

Adult↗
PubMed2000

Chlamydia and Chlamydiales: more than meets the eye.

This review summarizes the dramatic changes that have occurred in the taxonomy of bacteria known as Chlamydia. Best known for the diseases they cause in humans, these intracellular bacteria also comprise many species that are responsible for a wide variety of clinically and economically important diseases in livestock and companion animals. The old taxonomy grouped most of these species into C. psittaci because systematic methods for routinely distinguishing them were not available. DNA-based testing methods are now available that distinguish different chlamydial families, genera, and species. This summary reviews these tests and a number of oligonucleotide primers that distinguish these groups using PCR and PCR-RFLP. DNA-based methods are also being used to discover new families of chlamydia-like bacteria, at least one of which is responsible for abortion in cattle (Waddlia chondrophila). This review summarizes the pathogenic roles of the Chlamydiaceae, new families, and individual species within the order Chlamydiales. These discoveries create opportunities for veterinarians to carry out epidemiological studies of chlamydiae that previously were not possible.

Animals↗
PubMed1991

Evaluation of a DNA probe of plasmid origin for the detection of Chlamydia trachomatis in cultures and clinical specimens.

This study evaluates five cryptic plasmid-derived DNA probes in a 4-h slot-blot hybridization assay for the detection of Chlamydia trachomatis in cultures and clinical specimens. The probes, consisting of either the entire cloned 7.5 kbp cryptic plasmid pSE8 or one of four Hin dIII/Eco RI fragments measuring 710, 1055, 710, and 500 bp, respectively, were labelled with Photoprobe biotin. The probe was detected using a streptavidin-alkaline phosphatase conjugate followed by addition of BCIP and NBT. The sensitivity of the assay, using 25 ng of probe DNA, ranged from 50 pg (with the entire plasmid as probe) to 5 ng (with the 500 bp fragment as probe). A total of 103 reference strains of Chlamydia trachomatis and other bacteria were tested for reactivity with the probes. All 18 reference strains of C. trachomatis hybridized with the probes. None of the DNA from the heterologous organisms tested was found to hybridize with any of the probes. A total of 174 samples taken from patients visiting the STD clinic at the University Hospital, University of Seville were used in the study. The overall sensitivity of the assay, using the 710 bp biotinylated probe was 94.5% compared to culture while the specificity was 97.5%. Positive and negative predictive values were 96.5% and 97.5%, respectively. It appears that the plasmid-derived probes used in this study could serve as useful tools for the rapid and specific detection of Chlamydia trachomatis in cell cultures and clinical specimens.

Bacteria↗
PubMed2002

The role of Chlamydia trachomatis in prostatitis.

Ascending chlamydial infections have been thought to be an infective cause of prostatitis for the last three decades. Unfortunately, the definitive association between isolation of an infective agent and its prostatic origin is limited by various factors, although modern techniques of molecular biology for identification of the microorganisms are available. Two major problems are: (1) diagnostic material passing the urethra may reflect only urethral contamination, (2) prostatic biopsy specimens from the gland may also contain urethral material. The ejaculate has the same limitations, and an ideal test for detection of Chlamydia species in ejaculate specimens is not available yet. Investigations for local chlamydial IgA-antibodies may be useful; the overlap with Chlamydia pneumoniae and Chlamydia psittaci means a clear differentiation on an type-specific basis is necessary, which is normally provided by the 'elaborate' microimmunofluorescence test. Modern p-ELISAs using major outer membrane protein parts as antigens may deliver identical results in the future. In the follow-up of standardized prostatitis patients, a combination of such urological tests in EPS and seminal plasma combined with genital chlamydial DNA material, may further elucidate the chlamydial aetiology of prostate infection.

Antibodies, Bacterial↗
PubMed2002

Chlamydia trachomatis genes whose products are related to energy metabolism are expressed differentially in active vs. persistent infection.

The Chlamydia trachomatis genome encodes glycolysis and pentose phosphate pathway enzymes, two ATP/ADP exchange proteins, and other energy transduction-related components. We asked if and when chlamydial genes specifying products related to energy transduction are expressed during active vs. persistent infection in in vitro models and in synovia from Chlamydia-associated arthritis patients. Hep-2 cells infected with K serovar were harvested from 0-48 h post-infection (active infection). Human monocytes identically infected were harvested at 1, 2, 3, 5 days post-infection (persistent). RNA from each preparation and from synovial samples PCR-positive/-negative for Chlamydia DNA was subjected to RT-PCR targeting (a) chlamydial primary rRNA transcripts and adt1 mRNA, (b) chlamydial mRNA encoding enzymes of the glycolysis (pyk, gap, pgk) and pentose phosphate (gnd, tal) pathways, the TCA cycle (mdhC, fumC), electron transport system (cydA, cydB), and sigma factors (rpoD, rpsD, rpoN). Primary rRNA transcripts and adt1 mRNA were present in each infected preparation and patient sample; controls were negative for chlamydial RNA. In infected Hep-2 cells, all energy transduction-related genes were expressed by approximately 11 h post-infection. In monocytes, pyk, gap, pgk, gnd, tal, cydA mRNA were present in 1-2-day-infected cells but absent at 3 days and after; cydB, mdhC, fumC were expressed through 5 days post-infection. RT-PCR targeting mRNA from sigma factor genes indicated that lack of these gene products cannot explain selective transcriptional down-regulation during persistence. Analyses of RNA from synovial tissues mirrored those from the monocyte system. These data suggest that in the first phase of active chlamydial infection, ADP/ATP exchange provides energy required for metabolism; in active growth, glycolysis supplements host ATP. In persistence host, rather than bacterially produced, ATP is the primary energy source. Metabolic rate in persistent C. trachomatis is lower than in actively growing cells, as judged from assays for relative chlamydial primary rRNA transcript levels in persistent vs. actively growing cells.

Adenosine Triphosphate↗
PubMed2005

Can Chlamydia trachomatis directly damage your sperm?

Although Chlamydia trachomatis causes symptomatic infection in the lower genital tract of approximately 50% of men, its role in the upper genital tract is less well known. Moreover, for a number of reasons, mostly based on methodological aspects, the impact of chlamydia on semen quality is controversial. Overall, in-vivo studies of C trachomatis in men have provided conflicting evidence as to whether it is associated with reduced fertility. By contrast, in-vitro studies show that co-incubation of spermatozoa with chlamydia causes a significant decline in numbers of motile sperm and results in premature sperm death. Since evidence suggests that chlamydial lipopolysaccharide is the principal factor leading to sperm apoptosis, a new line of inquiry would be to measure the levels of lipopolysaccharide in semen and relate these to parameters of semen quality, including that of sperm function. If these new lines of inquiry are proven, this could lead to potentially novel approaches in the treatment of infertile men.

Chlamydia Infections↗
PubMed2024

Circulation of avian Chlamydia abortus in the Netherlands and community-acquired pneumonia: an outbreak investigation and retrospective cohort study.

BACKGROUND: In 2021, a novel group of Chlamydia strains in wild birds was classified as avian Chlamydia abortus, with unknown zoonotic potential. We report relevant features of avian C abortus infections from a Dutch family cluster and unrelated historical cases using clinical, epidemiological, and microbiological data. METHODS: An outbreak of avian C abortus started in the Netherlands in December, 2022. Source investigation was done using questionnaires to interview patients and environmental sampling. The outbreak strain of avian C abortus was cultured from three patients from whom sufficient material was available for culture and underwent whole-genome analysis. The outbreak strains and retrospective cohort study strains previously submitted to the National Human Psittacosis surveillance programme in the Netherlands between 2010 and 2022 were typed by partial ompA sequencing. Strains with the same aberrant ompA genotype were further analysed with XerC gene plasmid analysis and compared with closely related Chlamydia sequences available in GenBank. FINDINGS: An avian C abortus strain caused a cluster of respiratory illness in four family members. Three patients were hospitalised with community-acquired pneumonia, one of whom was admitted to the intensive care unit. The faeces of wild birds were considered a probable source for the index infection. For two family members, human-to-human transmission was a plausible route. Ten historical cases could be identified with avian C abortus with the same ompA genotype. All patients had been admitted to hospital, at least five developed pneumonia, and one died. INTERPRETATION: This cluster supports that avian C abortus strains can cause human infections and underlines that human-to-human transmission should be considered when tracing the source of such infections. FUNDING: National Institute for Public Health and the Environment and Dutch Ministry of Agriculture, Fisheries, Food Security and Nature. TRANSLATION: For the Dutch translation of the abstract see Supplementary Materials section.

Humans↗
PubMed2005

Characterization of the disulfide bonds and free cysteine residues of the Chlamydia trachomatis mouse pneumonitis major outer membrane protein.

Members of the genus Chlamydia lack a peptidoglycan layer. As a substitute for peptidoglycan, it has been proposed that several cysteine rich proteins, including the major outer membrane protein (MOMP), form disulfide bonds to provide rigidity to the cell wall. Alignment of the amino acids sequences of the MOMP from various serovars of Chlamydia showed that they have from 7 to 10 cysteine residues and seven of them are highly conserved. Which of these are free cysteine residues and which are involved in disulfide bonds is unknown. The complexity of the outer membrane of Chlamydia precludes at this point the characterization of the structure of the cysteines directly in the bacteria. Therefore, mass spectrometric analysis of a purified and refolded MOMP was used in this study. Characterization of the structure of this preparation of the MOMP is critical because it has been shown, in an animal model, to be a very effective vaccine against respiratory and genital infections. Here, we demonstrated that in this MOMP preparation four cysteines are involved in disulfide bonds, with intramolecular pairs formed between Cys(48) and Cys(55) and between Cys(201) and Cys(203). A stepwise alkylation, reduction, alkylation process using two different alkylating reagents was required to establish the Cys(48)-Cys(55) disulfide pair. The other residues in MOMP, Cys(51), Cys(136), Cys(226), and Cys(351), are free cysteines and could potentially form disulfide-linked complexes with other MOMP or other membrane proteins.

Amino Acid Sequence↗