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PubMed2000

Reexamining the prevalence of Chlamydia trachomatis infection among gay men with urethritis: implications for STD policy and HIV prevention activities.

BACKGROUND: Evidence of an STD-HIV interaction and the availability of noninvasive urine-based screening tests have resulted in an increased focus on chlamydial infections in men. GOAL: To evaluate the prevalence of chlamydial infections among men with urethritis at the San Francisco City Clinic (SFCC). STUDY DESIGN: In 1997, male SFCC patients diagnosed with urethritis were tested for chlamydia using urine-based ligase chain reaction and for gonorrhea using urethral culture. RESULTS: Gonorrhea was identified in 45% of men who have sex with men (MSM) versus 26% of men who have sex with women (MSW). Among men with gonorrhea, chlamydia coinfection was found among 15.2% of MSM and 8.4% of MSW. Among men with nongonococcal urethritis, 18% and 20% of MSM and MSW had chlamydial infection, respectively. Young age was associated with chlamydial infection in MSM. CONCLUSION: After a period of low chlamydial infection rates in MSM during the pre-AIDS era, infection rates are increasing among this population. SFCC's revised clinical practice guidelines include chlamydia testing of MSM with urethritis.

Adolescent↗
PubMed2001

Prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae in Turkey among men With urethritis.

BACKGROUND: Chlamydia trachomatis and Neisseria gonorrhoeae are known to cause urethritis. However, only a small number of studies in Eastern European countries have investigated the causes of urethritis. GOALS: To determine the prevalence of C trachomatis and N gonorrhoeae among men with symptomatic urethritis in Istanbul, Turkey, and to determine whether contact with a commercial sex worker increased the likelihood of chlamydial infections. STUDY DESIGN: Men with a diagnosis of urethritis at the Istanbul Faculty of Medicine were screened for C trachomatis and N gonorrhoeae by Abbott's ligase chain reaction (LCR) using either urethral swabs or first-void urine. N gonorrhoeae cultures were done on a subset of these patients. RESULTS: The study enrolled 813 men. All of the men denied condom use during their previous sexual exposures. The overall prevalence of C trachomatis, as determined by LCR, was 15.7%. Only 192 patients were screened for both organisms. N gonorrhoeae prevalence was 9.4%. There was no difference in the chlamydia prevalence between men who had contact with commercial sex workers (CSWs) and men who had no such contact (15.3% versus 17.2%). However, clients of foreign CSWs were more likely to have chlamydia than clients of registered Turkish CSWs. CONCLUSIONS: C trachomatis and N gonorrhoeae are commonly found in Turkish men with urethritis. The findings did not show more chlamydial infection among men who had contact with CSWs than among men who had no such contact. The failure to use condoms among these men must be addressed.

Adult↗
PubMed2003

Patient-delivered therapy for chlamydia: putting research into practice.

BACKGROUND: In 2001 California State lawmakers authorized patient-delivered therapy for sex partners of patients with chlamydial infection. Several studies have suggested that patient-delivered therapy is effective in the treatment of infected partners. GOAL: The goal was to inform clinicians of the effectiveness and feasibility of patient-delivered therapy for the management of partners of sexually transmitted disease cases. STUDY DESIGN: A review of studies regarding patient-delivered therapy was performed. A descriptive cross-sectional analysis of clinic data was also done. The proportion of patients with chlamydia receiving therapy for partners and stratification by year and selected characteristics were evaluated with statistical analysis software (SAS). RESULTS: Studies suggested patient-delivered therapy decreased the incidence of chlamydia infection and the risk of reinfection from an untreated partner. The annual proportion of cases in which patient-delivered therapy occurred at the San Francisco STD Clinic was approximately 23%. CONCLUSIONS: Patient-delivered therapy is a beneficial and feasible addition to partner notification in the management of chlamydia. Expansion of patient-delivered therapy should be considered seriously in public health policy and clinical care.

Adult↗
PubMed2005

Chlamydia screening of at-risk young women in managed health care: characteristics of top-performing primary care offices.

OBJECTIVES: Despite effective approaches for managing chlamydial infection, asymptomatic disease remains highly prevalent. We linked administrative data with physician data from the American Medical Association physician survey to identify characteristics of primary care offices associated with best chlamydia screening practices. STUDY: Criteria from the National Committee for Quality Assurance provided chlamydia screening rates. We defined top-performing offices as those with rates in the top decile among 978 primary care offices from 26 states. RESULTS: Offices screened an average of 16.2% of at-risk, young women, but top-performing offices screened 42.2%. Top-performing offices on average had more black physicians (12.5%, 5.1%, P = 0.001) and were more often located in zip code areas with median income less than $30,000 (22.6%, 5.5%, P = 0.001). CONCLUSIONS: Although chlamydia screening rates are alarmingly low overall, there is substantial variation across offices. Understanding predictors of better office performance may lead to effective interventions to promote screening.

Adolescent↗
PubMed2005

Management of Chlamydia cases and their partners: results from a home-based screening program organized by municipal public health services with referral to regular health care.

BACKGROUND: We evaluated the management of Chlamydia trachomatis cases and partners found in a systematic home-based chlamydia screening project in the Netherlands among 15- to 29-year-old women and men, organized by the Municipal Public Health Services (MHS). METHODS: Infected participants (165/8339 = 2%) were referred to regular curative services. The treating physician provided feedback on treatment and partner notification. RESULTS: Including the effect of a reminder, the treatment rate of all index cases was 91% (150/165); among persons with non-Dutch ethnicity, 81% (25/31). The majority of cases (82%) consulted the general practitioner for treatment as opposed to sexually transmitted disease/MHS clinics (18%). Eighty-five percent of cases were treated within 2 weeks. The confirmed treatment rate of partners in the last 6 months was 49% (86/176); 57% (81/141) for current versus 14% (5/35) for other partners. Patient referral was advised in an additional 18% (25/141) of current partners and in 9% (3/35) of other partners (potential treatment). CONCLUSION: Home-based chlamydia screening and treatment through regular treatment facilities has proven to be effective in the Netherlands. The necessity of a reminder to increase treatment rate and the lower treatment rate in non-Dutch high-risk groups deserve attention. Low confirmed treatment rate of current partners carries the potential of reinfection, and patient-delivered treatment should be expanded.

Adolescent↗
PubMed2005

Acceptability and consequences of screening for chlamydia trachomatis by home-based urine testing.

OBJECTIVE: The objective of this study was to study the acceptability and consequences of home-based chlamydia (CT) screening by Municipal Health Services (MHS) among 15- to 29-year-old participants. STUDY: This study consisted of a cross-section of 156 CT-positives and 600 random sampled CT-negatives after receiving the result of their CT test. RESULTS: Thirty-eight percent of the men and 59% of the women responded. The screening method was well-accepted. Seventy percent (52) of the CT-positives were surprised about their result. Infected women more often than men reported a feeling of being dirty and of anxiety about infertility. Curiosity for the CT result was decisive for participation in 68% and perception of personal risk was poor. The willingness to be tested regularly was determined by present chlamydial infection, young age, multiple lifetime partners, short relationship, and earlier test for chlamydia. CONCLUSIONS: Chlamydia screening organised by MHS is acceptable for future screening. Participants with an elevated risk are interested in screening as long as test kits are easily available. Counseling with focus on effects of CT, especially on women, is essential. Alternative approaches are needed to motivate men and non-Dutch high-risk groups.

Adolescent↗
PubMed2006

Condom use and risk of gonorrhea and Chlamydia: a systematic review of design and measurement factors assessed in epidemiologic studies.

BACKGROUND: Studies of condom use to reduce risk of most sexually transmitted infection provide inconsistent results. This inconsistency is often attributed to methodologic limitations yet has not been assessed systematically. OBJECTIVES: The objectives of this study were to review studies of condom use and risk of gonorrhea and chlamydia, and to evaluate the importance of 4 key design and measurement factors on condom effectiveness estimates. DESIGN: We reviewed studies published 1966-2004 to assess risk reduction for gonorrhea and/or chlamydia associated with male condom use. RESULTS: Of 45 studies identified, most found reduced risk of infection associated with condom use. All studies reviewed had methodologic limitations: only 28 (62%) distinguished consistent from inconsistent use; 2 (4%) reported on correct use or use problems; 13 (29%) distinguished incident from prevalent infection; and one (2%) included a population with documented exposure to infection. Eight of 10 studies with 2 or more of these attributes reported statistically significant protective effects for condom use versus 15 of 35 studies with zero or one attribute (80% vs. 43%, P = 0.04). CONCLUSIONS: Condom use was associated with reduced risk of gonorrhea and chlamydia in men and women in most studies, despite methodologic limitations that likely underestimate condom effectiveness. Epidemiologic studies that better address these factors are needed to provide more accurate assessment of condom effectiveness.

Ambulatory Care Facilities↗
PubMed2006

Prediction of Chlamydia trachomatis infection: application of a scoring rule to other populations.

BACKGROUND: Active case finding is crucial to reduce transmission and consequences of Chlamydia trachomatis (CT) infections. We previously proposed the use of a prediction rule for CT infection for selective screening of high-risk individuals in a population. To support such an application, the prediction rule needs to be validated in other populations. METHODS: We studied participants aged 15 to 29 years in a population-based study in Amsterdam (n = 1,788) and an outreach screening project among high-risk youth in Rotterdam (n = 172). Validity was indicated by discriminative ability (area under the receiver operating characteristic curve [AUC]) and by calibration, which was visualized in plots and tested with the Hosmer-Lemeshow (H-L) goodness-of-fit test. Cutoffs of predicted risk were examined for their effect on sensitivity and the fraction of participants that would need to be screened. RESULTS: Discriminative ability was reasonable both for the Amsterdam study (AUC 0.66; 95% confidence interval [CI], 0.58-0.74) and for the Rotterdam study (AUC 0.68; 95% CI, 0.58-0.79). The observed CT prevalence was lower than predicted in Amsterdam (H-L P = 0.02) and nonsignificantly higher in Rotterdam (H-L P = 0.20). By screening 77% of the Amsterdam population, 93% of the cases would have been detected, whereas in the Rotterdam study, no cases would be missed by screening 75%. CONCLUSION: The chlamydia prediction rule showed a reasonable external validity in two studies. These findings support the use of the rule as a tool for selective chlamydia screening, although only a limited fraction of participants can be excluded when a high sensitivity is required.

Adolescent↗
PubMed2007

Risk selection and targeted interventions in community-based control of chlamydia.

PURPOSE OF REVIEW: To describe recent developments in the community-based approach of high-risk groups for Chlamydia trachomatis infection, and to discuss the assessment of impact of selective systematic screening on the transmission of C. trachomatis in the community. RECENT FINDINGS: Two large home-based screening programs in Europe have recently shown that systematic postal screening for C. trachomatis infection is feasible, but certain high-risk groups are poor participators. This underscores the need for risk selection and targeted approaches. A prediction rule has been developed which can assist in identifying high-risk groups and can be used as a tool for (self) selection for screening. The Internet has been shown to be a promising medium to promote chlamydia testing. School-based programs also succeed in including high-risk groups in screening programs. Recently developed dynamic simulation models, which take into account transmission of C. trachomatis, can assist in the development and evaluation of targeted screening strategies. SUMMARY: Chlamydia will not likely be controlled by one standard approach. Risk selection strategies need further development and different systematic approaches at the community level, including postal screening, school-based screening, and the Internet may produce the desired public health effect of decreasing morbidity and reducing the transmission of C. trachomatis in the community.

Chlamydia Infections↗
PubMed1992

Heterotypic protection of mice against chlamydial salpingitis and colonization of the lower genital tract with a human serovar F isolate of Chlamydia trachomatis by prior immunization with recombinant serovar L1 major outer-membrane protein.

Intrauterine infection of mice with a human genital tract isolate of Chlamydia trachomatis (serovar F) resulted in salpingitis. In some cases, oviduct damage was sufficient to cause infertility due to lumenal blockage. Parenteral immunization with a purified, heterologous, recombinant major outer-membrane (rMOMP) preparation reduced the proportion of animals developing severe salpingitis by 77% compared with mock-immunized controls, but failed to reduce chlamydial colonization of the lower genital tract. In contrast, mice immunized with rMOMP directly into the Peyer's patches to stimulate mucosal immunity shed fewer chlamydiae from the vagina than controls, but showed little reduction in oviduct damage. No consistent correlation was observed between antibody levels to rMOMP in immunized mice and reduced lower genital tract colonization. Immunization with rMOMP via the presacral space, a route previously shown to stimulate mucosal immunity in the genital tract, produced high levels of circulating anti-rMOMP IgG but only traces of anti-rMOMP IgA in vaginal secretions. There was no difference in the severity of salpingitis in these animals compared with mock-immunized controls. Immunization with rMOMP conferred no protection against infertility resulting from direct inoculation of chlamydiae into the oviducts.

Animals↗
PubMed2002

Infection of myocytes with chlamydiae.

Chlamydial infection has been associated with myocarditis in animals and humans. However, the mechanism resulting in myocarditis following infection is not known. Here, evidence is presented that both Chlamydia trachomatis and Chlamydia pneumoniae can infect and replicate in myocytes isolated from neonate rats. The infected myocytes contained chlamydial inclusions, indicative of chlamydial growth, and infectious particles were recovered from the infected myocytes. It was also found that chlamydial infection at a late stage induced significant damage to the infected myocytes, as evidenced by an increased lactate dehydrogenase release, reactive oxygen species production and a reduced ATP level. However, no nuclear apoptosis was detected in the infected myocytes. Collectively, these observations have demonstrated that Chlamydia spp. are able to both infect and damage myocytes, suggesting a potential role of chlamydial infection in myocarditis.

Adenosine Triphosphate↗
PubMed1987

Comparison of detection procedures for Chlamydia trachomatis, including enzyme immunoassays, in a mouse model of genital infection.

Two chlamydial enzyme immunoassays, Chlamydiazyme and IDEIA, were evaluated in a mouse model of chlamydial genital-tract infection. The Chlamydiazyme assay and the IDEIA were assessed on specimens from 10 and 11 mice, respectively. The animals were infected with Chlamydia trachomatis, strain SA2f, and the results obtained by these methods on vaginal specimens taken on 4 or 5 occasions during 41-42 days were compared with those obtained in cell culture and to a less extent by the MicroTrak direct immunofluorescence test. In comparison with culture, the Chlamydiazyme assay had a sensitivity of 62% and a specificity of 92%; IDEIA had a sensitivity of 76% and a specificity of 94%. These assays sometimes did not detect chlamydiae in specimens taken immediately before specimens which proved positive by culture and the immunoassays were less sensitive if swabs were taken after those for culture. The IDEIA also failed to detect chlamydiae in the late stage of the murine infection when chlamydial elementary bodies were seen by immunofluorescence. The implications of the observations for investigations in the human field as well as for further studies in the mouse are discussed.

Animals↗
PubMed1993

The morphology of Chlamydia pneumoniae.

The morphology of a recently isolated strain of Chlamydia pneumoniae, YK-41, was compared by electronmicroscopy with C. pneumoniae TWAR, Chlamydia trachomatis L2/434/Bu and Chlamydia psittaci Cal 10. The results showed that "pear-shaped" morphology was not typical of C. pneumoniae. Basic morphological features, such as surface projections and hexagonally arrayed, regular structures in the inside layer of the outer membrane of elementary bodies, were very similar in these strains. The structure of strain YK-41 was identical with that of C. trachomatis and C. psittaci, but the profiles of elementary bodies were different from those of C. pneumoniae TWAR strains.

Cell Membrane↗
PubMed2004

Effects of Chlamydia trachomatis infection on the expression of natural killer (NK) cell ligands and susceptibility to NK cell lysis.

Natural killer (NK) cells are an important component of the immediate immune response to infections, including infection by intracellular bacteria. We have investigated recognition of Chlamydia trachomatis (CT) by NK cells and show that these cells are activated to produce interferon (IFN)-gamma when peripheral blood mononuclear cells (PBMC) are stimulated with CT organisms. Furthermore, infection of epithelial cell lines with CT renders them susceptible to lysis by human NK cells. Susceptibility was observed 18-24 h following infection and required protein synthesis by the infecting chlamydiae, but not by the host cell; heat or UV inactivated chlamydiae did not induce susceptibility to NK cell lysis. CT infection was also shown to decrease the expression of classical and non-classical major histocompatibility complex (MHC) molecules on infected cells, thus allowing recognition by NK cells when combined with an activating signal. A candidate activating signal is MICA/B, which was shown to be expressed constitutively on epithelial cells.

Bacterial Proteins↗
PubMed1989

Chlamydia trachomatis infection in late pregnancy: a prospective study.

During a 1-year period, 3309 women were screened in pregnancy for Chlamydia trachomatis infection. A cervical swab was taken and chlamydial antigen was detected, using a monoclonal antibody ELISA technique, in 198 women (6%). The prevalence of chlamydial infection was high in women under 20 years (14.5%), single women (14.2%) and black women (16.8%). Binomial regression of these data estimates a relative risk of 2.9 for women under 20 years compared with women aged 25 and over. There was an interaction between race and marital status with a high risk in single white and single asian women (2.3, 4.5 respectively) but a similar risk in black single and black married women (3.0, 4.0 respectively). Parity and social class did not effect the prevalence of antigen carriage. There was no demonstrable effect of maternal antigen carriage on outcome of pregnancy, gestation or admission to neonatal unit. Infants of 174 antigen-positive mothers were followed-up. Tissue culture for Chlamydia trachomatis was positive in 43 (24%) infants. Complications occurred in 23 (53%): 17 had conjunctivitis, three had lower respiratory tract infection and three both complications. Amongst 131 chlamydia-negative infants, complications occurred in 21 (16%). Since this infection, in infants, responds promptly to erythromycin therapy, screening and treatment in pregnancy will convey little benefit in prevention of perinatal morbidity or perinatal mortality.

Adult↗
PubMed1991

Immunohistochemical detection of chlamydiae in formalin-fixed tissue sections: comparison of a monoclonal antibody with yolk derived antibodies (IgY).

Immunohistological detection of chlamydiae in formalin-fixed and paraffin-embedded sections of various organs from several species is described. In a retrospective study, two antisera, a commercially available monoclonal murine antibody (IgMur) and vitelline immunoglobulins (IgY), extracted from the egg yolk of immunized hens, were compared and tested for their applicability under routine condition. Both antisera were applied to tissues from which chlamydiae had been isolated or in which the presence of chlamydiae had been suspected in specially stained sections. Antigen labelling was optimal with the monoclonal antibody. Vitelline immunoglobulins produced some unspecific reactions, especially in lung tissue sections. Because of the antigenic relationship between the vitelline antibodies and tissues of birds, IgY are not suitable for the detection of psittacosis on avian substrates, when using an indirect immunological method. Staining in other tissues e.g. intestine or placenta was of equal quality as that attained with monoclonal antibodies. Depending on the advantages and disadvantages in every individual case, one of the two antibodies may be chosen for further studies. Vitelline antibodies should be preferred with respect to animal welfare.

Animals↗
PubMed2005

Drosophila melanogaster S2 cells: a model system to study Chlamydia interaction with host cells.

Chlamydia spp. are major causes of important human diseases, but dissecting the host-pathogen interactions has been hampered by the lack of bacterial genetics and the difficulty in carrying out forward genetic screens in mammalian hosts. RNA interference (RNAi)-based methodologies for gene inactivation can now be easily carried out in genetically tractable model hosts, such as Drosophila melanogaster, and offer a new approach to identifying host genes required for pathogenesis. We tested whether Chlamydia trachomatis infection of D. melanogaster S2 cells recapitulated critical aspects of mammalian cell infections. As in mammalian cells, C. trachomatis entry was greatly reduced by heparin and cytochalasin D. Inclusions were formed in S2 cells, acquired Golgi-derived sphingolipids, and avoided phagolysosomal fusion. Elementary body (EB) to reticulate body (RB) differentiation was observed, however, no RB to EB development or host cell killing was observed. RNAi-mediated inactivation of Rac, a Rho GTPase recently shown to be required for C. trachomatis entry in mammalian cells, inhibits C. trachomatis infection in S2 cells. We conclude that Drosophila S2 cells faithfully mimic early events in Chlamydia host cell interactions and provides a bona fide system to systematically dissect host functions important in the pathogenesis of obligate intracellular pathogens.

Actins↗
PubMed1988

The frequency of Chlamydia trachomatis in acute epididymitis.

Twenty-five patients with bacteriologically proven epididymitis were studied between 1984 and 1986. Thirteen were less than 35 years old and in 11 of them Chlamydia trachomatis was isolated; of the 2 remaining patients Escherichia coli was found in 1 and Neisseria gonorrhoeae in the other. In patients more than 35 years old, gram negative bacteria were the cause of infection in 10 and only 1 case was attributable to Chlamydia trachomatis. These results suggest that Chlamydia trachomatis is much more frequent in men under the age of 35 and the difference is statistically significant.

Acute Disease↗