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 1,243 records · Page 69Linked to original sources
PubMed2004

A CD14 promoter polymorphism is associated with CD14 expression and Chlamydia-stimulated TNF alpha production.

CD14, a pattern recognition receptor on monocyte and macrophage, plays a central role in innate immunity through recognition of bacterial lipopolysaccharide and initiation of inflammatory response. Recently, CD14/-260C>T promoter gene polymorphism has been found to be related to a risk of inflammatory diseases. Our results showed that the C allele frequency among Chinese in Taiwan was lower than those in Western countries. The membrane CD14 expression was significantly higher in TT as compared with CT and CC genotypes (P=0.034, 0.044, respectively). There was a higher level of soluble CD14 in TT and CT genotypes than in CC genotypes. In addition, TNFalpha production in whole blood was significantly higher in TT genotype than in CC genotype after stimulation by Chlamydiae. In conclusion, the single base pair polymorphism of CD14 promoter gene is associated with CD14 expression and Chlamydia-stimulated TNFalpha production, and may thus play some role in the chlamydia-induced inflammatory response.

Adult↗
PubMed1997

Type III secretion genes identify a putative virulence locus of Chlamydia.

Four genes of Chlamydia psittaci strain guinea pig inclusion conjunctivitis (GPIC), whose predicted products are highly homologous to structural and regulatory components of a contact-dependent or type III secretion apparatus, were isolated. Related to genes present in several animal and plant bacterial pathogens, these genes may represent a section of a previously undetected chromosomal virulence locus analogous to several recently described virulence-associated type III secretion loci. The existence of contact-dependent secretion in Chlamydia strongly suggests that these bacteria use pathogenic mechanisms that are similar to those of other intracellular bacterial pathogens. Unlike other intracellular bacteria, however, chlamydiae are metabolically inactive extracellularly and only become capable of global protein synthesis several hours after infection. This implies that chlamydial contact-dependent secretion is only active from within, uniquely after the bacteria have been internalized by eukaryotic cells. The possible role(s) of this pathway in chlamydial pathogenesis are discussed.

Amino Acid Sequence↗
PubMed2005

Changes in testing methods for genital Chlamydia trachomatis in New South Wales, Australia, 1999 to 2002.

BACKGROUND: Over the last decade, significant advances have occurred in the area of chlamydia diagnostics. The relative frequency of different testing methods employed in the diagnosis of Chlamydia trachomatis infection in New South Wales has not been previously reported. METHODS: Testing methods--both laboratory method and specimen type--employed in the diagnosis of chlamydia cases notified in New South Wales between 1999 and 2002 were collated from Health Department records. RESULTS: During a period of increasing notifications, the proportion of men diagnosed with C. trachomatis using nucleic acid tests (NATs) increased from 36% in 1999 to 90% in 2002. Among women, the proportion diagnosed using NATs increased from 42% in 1999 to 92% in 2002. Urine samples were consistently used in the diagnosis of two-thirds of the men, and one-third of the women. CONCLUSION: Between 1999 and 2002, a rapid shift towards NATs for genital C. trachomatis took place in New South Wales.

Chlamydia Infections↗
PubMed2006

A survey of partner notification practices among general practitioners and their use of an internet resource for partner notification for Chlamydia trachomatis.

OBJECTIVES: To determine in which circumstances Victorian general practitioners (GPs) offer chlamydia testing to patients, the attitudes of GPs in relation to contact tracing, how often GPs use a pre-printed partner letter and patient brochure and what proportion of GPs have immediate internet access in their consulting rooms. METHODS: This study involved two parts, an initial survey of a sample of GPs in Victoria and a study of GP use of a website that provided treatment guidelines, a printable client brochure and a partner letter. RESULTS: Of 418 eligible GPs, 221 (53%, 48-58%, 95% CI) returned completed surveys. Of these, 213 (97%, 93-99%, 95% CI) GPs believed that patients were largely responsible for notifying partners. Partner letters were rarely used: 167 (76%, 70-81%, 95% CI) GPs reported they never used partner letters, 18 (8%, 5-13%, 95% CI) GPs reported rare use and 23 (10%, 7-15%, 95% CI) GPs reportedusing them sometimes. Of the GPs, 181 (82%, 77-87%, 95% CI) reported they would find a partner letter and patient brochure on a website helpful. During the study, the website was accessed by 28 GPs (25%, 17-34%, 95% CI) in Gippsland and 17 GPs (8%, 5-13%, 95% CI) in Geelong who received positive chlamydia results on 110 and 208 clients respectively. CONCLUSIONS: GPs mostly considered patients responsible for partner notification but uncommonly used partner letters or an information brochure to assist them. Importantly, GPs reported that they could improve partner notification if further support was provided. In addition, when a website was provided with useful documents on it, up to 25% of GPs used it. This indicates that simple and inexpensive interventions can support GPs with strategies that may improve the control of chlamydia.

Adult↗
PubMed1994

Comparison of Giemsa and fluorescent monoclonal antibody staining of inoculated cell cultures for diagnosis of Chlamydia trachomatis.

Three methods of isolation and identification of Chlamydia trachomatis inclusions in cell monolayers were compared: Giemsa staining followed by darkfield microscopy of cycloheximide treated Buffalo green monkey kidney monolayers (BGM), fluorescent monoclonal antibody staining of cycloheximide treated BGM and of HeLa 229 monolayers. In an unselected group of 895 patients with suspected chlamydial infections including contacts of symptomatic patients, significantly more positive chlamydia isolates were detected with immunofluorescent monoclonal antibody staining of BGM and HeLa 229 than with Giemsa staining followed by darkfield microscopy on BGM. However, there was no disparity between the 2 staining methods with specimens from 156 patients with untreated non-gonococcal urethritis. In all chlamydia positive specimens, significantly more inclusions were seen after BGM-immunofluorescence than after HeLa-immunofluorescence or BGM-Giemsa. The extra cost associated with immunofluorescence staining was justified by the time saved in scanning.

Animals↗
PubMed1995

Comparison of antigen detection, polymerase chain reaction and culture for detection of Chlamydia trachomatis in genital infection.

An in-house polymerase chain reaction (PCR) test using ribosomal RNA gene primers was compared with chlamydia antigen detection (DIF) and culture for the detection of Chlamydia trachomatis. Five hundred and forty-eight fresh (unstored) genital swabs and 174 urines (collected at the same time) from patients attending a sexually-transmitted diseases clinic were examined. PCR, DIF and culture detected chlamydia in 43, 35 and 42 swabs respectively from the 43 resolved positive cases. The specificity on the resolved negative specimens was 100% for each of the tests. From the urines, PCR and DIF detected the organism in 16 and 15 cases respectively of the 23 resolved positive males tested but in only 2 and 3 cases respectively of the 9 resolved positive females tested. Specificities were 100% in all cases. Both of the non-culture tests manifested problems with urine due to inhibitory activity (in PCR test) or excessive debris (in DIF test) in about 5% of the specimens. Culture of the urines yielded sensitivities of 40% in the males and 22% in the females. Overall PCR was more sensitive than either culture or DIF on both urethral and cervical swabs and urines. The urines yielded less than three-quarters the number of positives that was obtained from the swabs and were considered to be an unsatisfactory specimen for chlamydial diagnosis. It is concluded that PCR is a satisfactory alternative to culture on genital swabs and may be preferable in situations where the viability of the organisms is in question. DIF remains useful because of its speed and simplicity but is insufficiently sensitive to be relied upon by itself.

Adolescent↗
PubMed2006

Urine-based testing for Chlamydia trachomatis using polymerase chain reaction, leucocyte esterase and urethral and cervical smears.

The performance of Roche polymerase chain reaction (PCR) Amplicor to detect Chlamydia trachomatis in first-voided urine specimens from 422 males and 456 females attending two clinics for sexually transmitted infections was evaluated in comparison with cultures of urethral and cervical specimens. At the same time, the ability of leucocyte esterase (LE) in first-voided urine and the presence of leucocytes in urethral and cervical smears to identify C. trachomatis-infected individuals based on PCR and culture was determined. The prevalence of C. trachomatis infection was 10.9% in men and 7.7% in women. Sensitivity, specificity, positive predictive value and negative predictive value of Amplicor was 93.5%, 99.7%, 97.7% and 99.2% in males and 91.4%, 99.5%, 94.1% and 99.3% in females. All Chlamydia-infected men were identified by means of a combination of urethritis (4 leucocytes in the urethral smear) and/or a positive LE test in urine, although the specificity was only 42.2%. In women, the combination of urethritis and/or cervicitis and/or a positive LE test identified 85.7% of Chlamydia-infected patients with a specificity of 38.2%. It is concluded that a combination of urethral and/or cervical smears and LE testing of urine can be used as a screening test to select patients, especially males, for specific C. trachomatis testing.

Adolescent↗
PubMed2002

Is the increase in notifications of Chlamydia trachomatis infections in Sweden the result of changes in prevalence, sampling frequency or diagnostic methods?

Based on clinical and laboratory surveillance data, trends in the incidence rates of genital Chlamydia trachomatis infections in Sweden between 1991 and 1999 were analysed according to age group and sex. The influence of changes in laboratory methods on the reported infections was assessed. After a decrease in the incidence rate of infection of 36% between 1991 and 1994, followed by a period of stability, a 20% increase was observed between 1997 and 1999 (from 157 to 189/100,000). Between 1991 and 1999 the female:male ratio decreased from 1.7 to 1.4. Incidence rates started to increase in 1994 in the 15-19 y age group for both sexes. Crude Chlamydia positivity increased from 4.1% (352,050 people tested) in 1994 to 5.4% (305,946 people tested) in 1999. This increase in Chlamydia positivity was seen both in laboratories that had changed to more sensitive methods and in those that had not. Changes in laboratory methods can therefore only partially explain the increase in notified cases. Increased screening of men may have contributed to the increase, but rising incidence rates in all young age groups of both sexes suggest a true increase in prevalence.

Adolescent↗
PubMed1993

Seasonality of Chlamydia trachomatis genital infections in university women.

Previous studies have shown seasonal fluctuations in the incidence of most sexually transmitted diseases, with a peak in the third quarter, but none have specifically evaluated Chlamydia trachomatis genital infections. From 1989 to 1991, 8,234 women presenting to the student health centers of Florida's two largest universities for routine gynecologic care and diagnosis of sexually transmitted diseases were tested for Chlamydia trachomatis genital infections. The bimonthly variation in incidence was statistically significant, with a significant peak in the months of August and September of 10.70%, compared with the yearly average of 8.74%. Because the pattern of incidence of chlamydia in university women is seasonal, those concerned with healthcare should increase their efforts during the third quarter to identify infected individuals and to provide preventive programs.

Adult↗
PubMed2005

Prevalence of rectal, urethral, and pharyngeal chlamydia and gonorrhea detected in 2 clinical settings among men who have sex with men: San Francisco, California, 2003.

BACKGROUND: The Centers for Disease Control and Prevention developed screening and diagnostic testing guidelines for chlamydia and gonorrhea at urethral, rectal, and pharyngeal sites for men who have sex with men (MSM). However, in most clinical settings, rectal chlamydial testing is not performed for MSM, and primarily sexually transmitted disease (STD) clinics alone perform routine rectal and pharyngeal gonorrhea screening for asymptomatic men. METHODS: We evaluated the prevalence of rectal, urethral, and pharyngeal chlamydial and gonococcal infections among MSM seen at the municipal STD clinic and the gay men's community health center. We also determined the proportion of asymptomatic rectal infections, described the patterns of single and multiple anatomic sites of infection, and evaluated the proportion of chlamydial infections that would be missed and not treated if MSM were not routinely tested for chlamydia. We tested specimens using previously validated nucleic acid amplification tests (NAATs). RESULTS: The prevalence of infection varied by anatomic site (chlamydia: rectal, 7.9%; urethral, 5.2%; and pharyngeal, 1.4%; for gonorrhea, rectal, 6.9%; urethral, 6.0%; and pharyngeal, 9.2%). Approximately 85% of rectal infections were asymptomatic supporting the need for routine screening. Because 53% of chlamydial infections and 64% of gonococcal infections were at nonurethral sites, these infections would be missed and not treated if only urethral screening was performed. In addition, >70% of chlamydial infections would be missed and not treated if MSM were tested only for gonorrhea. CONCLUSIONS: Because these infections enhance both HIV transmission and susceptibility, clinical settings serving MSM should evaluate the prevalence of chlamydial and gonococcal infections by anatomic site using validated NAATs.

Adult↗
PubMed1992

Inapparent genital infection with Chlamydia trachomatis and its potential role in the genesis of Reiters syndrome.

An infectious etiology has been suggested for Reiter's syndrome (RS) because the disease has often been observed to follow episodes of urethritis or dysentery. Despite demonstrations of bacterial antigens in the synovial tissues of RS patients, it is not clear whether viable organisms are present in the synovium in any particular stage of this disease. Furthermore, it is not clear how either viable organisms or their product(s) might reach the joints. Infection with the bacterium Chlamydia trachomatis is the most common sexually transmitted disease in the United States, and as such this organism has emerged as a primary pathogen associated with RS. Previous work from our group has shown that synovial biopsy tissues from a majority of RS patients studied show significant levels of apparently intact chlamydial RNA, even when synovial or urethral cultures from the same patients are unequivocally negative for the organism. We show here that inapparent urethral infection with chlamydia occurs with high prevalence in men, and that inapparent cervical infection with the organism occurs at high prevalence in women. These data provide an important link in the relationship between initial chlamydial infection and possible subsequent genesis of RS, and they may give useful insight into mechanisms by which chlamydial infection can lead to development of this disease. Our data argue further that inapparent infection may be a significant factor in pathogenesis for all chlamydia-related diseases, and they suggest that, contrary to current ideas, C. trachomatis can generate disseminated infection.

Arthritis, Reactive↗
PubMed2000

Repeat Chlamydia trachomatis infection in women: analysis through a surveillance case registry in Washington State, 1993-1998.

Repeat infections with Chlamydia trachomatis are associated with increased risk for long-term sequelae. The authors analyzed the frequency and predictors of repeat chlamydial infection by using a population-based chlamydia registry in Washington State and evaluated whether women would seek care at the same clinic for repeat infections. Among 32,698 women with an appropriately treated initial chlamydial infection during 1993-1998, 15% developed one or more repeat infections during a mean follow-up time of 3.4 years. Among women less than age 20 years at the time of initial infection, 6% were reinfected by 6 months, 11% by 1 year, and 17% by 2 years. Young age was the strongest predictor for one and two or more repeat infections after controlling for the length of follow-up and other variables. Only 36% of the repeat infections were diagnosed at the same clinical setting as the initial infection, and 50% were diagnosed at the same type of clinic. Adolescent girls had the least consistency in the source of care for chlamydia. This study suggests that efforts to prevent repeat chlamydial infection in young women remain an urgent public health priority and that the burden of repeat infection may be substantially higher than estimates from clinic-based studies.

Adolescent↗
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↗
PubMed2006

Lessons learned from recruiting young female students to a randomised controlled trial of chlamydia screening.

BACKGROUND: Recruitment is a problem in many trials. Two female medical students offered to help with recruiting problems in a community-based trial of chlamydia screening to prevent pelvic inflammatory disease. We need to recruit 2500 sexually active female students and ask them to provide a self-taken low vaginal swab and complete a questionnaire with follow-up after a year. OBJECTIVES: To identify recruitment difficulties in a community-based trial of chlamydia screening and to investigate how they might be overcome. DESIGN: Descriptive study. SETTING: London South Bank and Kingston Universities. METHODS: The students observed the recruitment methods used for the first 4 months of the trial. This comprised single researchers recruiting individual women in student bars and common rooms. With the researchers they piloted a new method of group recruitment with pairs of researchers making announcements at the end of lectures after first sending out all male students and those aged>25 years. This involved extra time planning and liaising with the lecturers in advance of recruitment sessions. RESULTS: The recruitment rate had been averaging only 25 participants per week. Many students were ineligible: never been sexually active, too old, recently been tested for chlamydia. Many eligible students were reluctant to take part because of embarrassment or anxiety about providing a swab. Using a new method of group recruitment after lectures we recruited 192 participants in 2 weeks. CONCLUSION: For a study on a sensitive topic, two researchers recruiting women in groups after lectures may be a more effective and cost-effective way than individual recruitment by researchers working alone.

Adult↗
PubMed2002

Chlamydia antibody testing in screening for tubal factor subfertility: the significance of IgG antibody decline over time.

BACKGROUND: Chlamydia (C.) trachomatis antibody testing in screening for tubal factor subfertility is limited by false negative results, i.e. negative Chlamydia antibody tests in patients with tubal pathology at laparoscopy. The present study was performed to determine whether decline in C. trachomatis IgG antibodies over time is responsible for those false negative results. METHODS: A total of 39 women with an initial titre of > or =64 were re-studied after 4-7 years. A new serum sample was collected from each patient. The initial and the second serum sample were tested for C. trachomatis IgG antibodies using a micro-immunofluorescence assay (MIF). A species-specific enzyme-linked immunosorbent assay (ELISA) was used to validate the MIF test results. All patients filled out a questionnaire to determine risk factors for renewed C. trachomatis infection between the initial and second serum sample. RESULTS: Seven of the 39 patients (18.0%) showed a decline (>2 titre steps) in IgG antibodies by MIF over a period of 4-7 years, but IgG antibodies never became undetectable. In the 7/39 patients who showed a decline by MIF, signal/cut-off values by ELISA did not change. CONCLUSION: A decline in IgG antibody titre is not a significant cause of false negative Chlamydia antibody test results.

Adult↗
PubMed1979

Infection with Chlamydia trachomatis: involvement of multiple anatomic sites in neonates.

In a study of infection due to Chlamydia trachomatis in infants, chlamydiae were recovered not only from the conjunctiva and respiratory tract but also from the vagina and rectum. The timing of recovery suggested that the vagina and conjunctivae are exposed to chlamydiae at birth and that pneumonia and gastrointestinal infection occur later. Sampling of the rectum may be a useful procedure for the diagnosis of chlamydial disease in infants.

Chlamydia Infections↗
PubMed1982

Serology of Chlamydia trachomatis in infants.

Sera from 502 infants with pneumonia were tested for antibodies to Chlamydia trachomatis by the microimmunofluorescence test; 175 (34.9%) were positive for IgM antibodies (titer, greater than or equal to 1:32). Chlamydiae were recovered from 42 (46.2%) of 91 IgM antibody-positive infants as compared with six (3.3%) of 181 IgM antibody-negative infants (P less than 0.0001). Two (4%) of 46 of the infants with inclusion conjunctivitis, but not pneumonia, had titers of IgM antibody of greater than or equal to 1:32; both shed the organism from the rectum. IgM antibody to C. trachomatis is not maternally transmitted to infants and was detected at a low rate (1.1%) in infants with nonpneumonic conditions. Diagnosis of pneumonia due to Chlamydia in infants by isolation of the agent is slow and unreliable. High levels of IgM antibody (greater than 1:32) appear to reflect a systemic chlamydial infection and offer the possibility of a same-day diagnosis. Thus, the detection of specific IgM antibodies to C. trachomatis may be the method of choice in diagnosing chlamydial pneumonia in infants.

Antibodies, Viral↗
PubMed1985

The interaction of Chlamydia trachomatis with host cells: ultrastructural studies of the mechanism of release of a biovar II strain from HeLa 229 cells.

Serotypes of Chlamydia trachomatis classified as biovar II strains (immunotypes A, Ba, and B-K) are currently recognized as important human pathogens that produce disease characterized by a rather complex pathogenesis. We have studied some morphological phenomena in the interaction of C. trachomatis (strain UW3/Cx, serotype D) with HeLa 229 cells to define the mechanisms of release of these obligate intracellular parasites. Fluorescent-antibody staining of unfixed HeLa cells infected with chlamydiae suggested that this biotype of C. trachomatis can exit cells without concomitant death of the host cell. The mechanisms by which chlamydiae were released from cells were studied by scanning and transmission electron microscopy. Ultrastructural observations indicated that the chlamydial inclusion was segregated from host cytoplasm and transported to the host cell surface by a process similar to exocytosis. These observations of interactions between C. trachomatis and the host cell in vitro may be relevant for understanding the complex pathogenesis these organisms produce in vivo, specifically their ability to produce asymptomatic or latent infections.

Chlamydia Infections↗