Evaluation of a rapid assay for detection of Chlamydia trachomatis infections in outpatient clinics in South Kalimantan, Indonesia.
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A multicenter cross-sectional survey was conducted comparing a commercially available chlamydial optical immunoassay (OIA) to the chlamydial ligase chain reaction (LCR). Endocervical samples from 415 outpatients visiting clinics from three hospitals in South Kalimantan, Indonesia, were evaluated. Relative to the LCR, the overall sensitivity and specificity of the OIA were 31.6 and 98.9%, respectively. The sensitivity of the OIA varied among the three hospital laboratories, ranging from 20 to 50%. The OIA performance was slightly lower on samples from patients attending dermatovenereology clinics than on samples from nondermatovenereology clinic patients. The results indicate that the OIA did not perform well compared to LCR. (+info)
Development of a quantitative gene expression assay for Chlamydia trachomatis identified temporal expression of sigma factors.
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Chlamydia trachomatis is an important human pathogen which possesses a unique bi-phasic developmental cycle. We used lightcycler methodology to quantitatively measure gene transcript levels in C. trachomatis strain L2. By measuring 16S rRNA transcript levels, we determined C. trachomatis L2 to have a generation time of approximately 3 h and an inclusion burst size of 200-300 particles. The three chlamydial sigma factor genes rpoD (sigma66), rpsD (sigma28) and rpoN (sigma54) exhibited different patterns of temporal expression. rpoD was central to early chlamydial development, whereas rpsD and rpoN were temporally expressed, coinciding with elementary body (EB) to reticulate body (RB) conversion and RB to EB conversion, respectively. (+info)
Chlamydia trachomatis: impact on human reproduction.
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Chlamydia trachomatis infections are the most prevalent bacterial sexually transmitted infections (STI) recognized throughout the world. Worldwide, the magnitude of morbidity associated with sexually transmitted chlamydial infections is enormous. C.trachomatis is a common cause of urethritis and cervicitis, and sequelae include pelvic inflammatory disease (PID), ectopic pregnancy, tubal factor infertility, epididymitis, proctitis and reactive arthritis. The sharp worldwide increase in the incidence of PID during the past two decades has led to the secondary epidemics of tubal factor infertility and ectopic pregnancy. Chlamydial PID is the most important preventable cause of infertility and adverse pregnancy outcome. Chlamydial infections, like STI in general, are primarily a woman's health care issue since the manifestations and consequences are more damaging to the reproductive health in women than in men. Based on the available evidence, approximately 20% of women with chlamydial lower genital tract infection will develop PID, approximately 4% develop chronic pelvic pain, 3% infertility, and 2% adverse pregnancy outcome. However, these estimates are based on relatively weak evidence. Research on the link between C.trachomatis and male aspects of infertility has been much more limited. Currently recommended treatment regimens include azithromycin in a single dose or doxycycline for 7 days. These therapies are highly efficacious. Timely management of sex partners is essential for decreasing the risk for re-infection. Immunopathogenesis of C.trachomatis infection is one of the main focal points of current research into Chlamydia. Chlamydial infection fills the general prerequisites for disease prevention by screening, i.e. chlamydial infections are highly prevalent, usually asymptomatic, are associated with significant morbidity, can be reliably diagnosed, and are treatable. Screening programmes for C.trachomatis will be of paramount importance in the prevention of long-term sequelae. The cost of screening is only a fraction of the health care costs incurred due to complications resulting from undiagnosed and untreated chlamydial infections. Current strategies to control C.trachomatis still largely depend on clinic-based screening of symptomatic patients, and have not been successful. The development of highly sensitive and specific nucleic acid amplification tests for the diagnosis of chlamydial infections has been an important advance in the ability to conduct population-based screening programmes to prevent complications. Thus, the case for screening is clearly made, but much detail remains to be worked out. (+info)
In-vitro activity of gatifloxacin against Chlamydia trachomatis and Chlamydia pneumoniae.
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We compared the activity of gatifloxacin, a new quinolone, ofloxacin and erythromycin against five isolates of Chlamydia trachomatis and 20 isolates of Chlamydia pneumoniae, including TW183 and clinical isolates from the USA and Japan. Testing was done in cycloheximide-treated HEp-2 cells. Gatifloxacin was slightly less active against C. trachomatis and slightly more active against C. pneumoniae than ofloxacin, with MICs at which 90% of the isolates had no inclusions and minimal chlamydicidal concentrations at which 90% of the isolates had no inclusions after passage of 0.25 mg/L. Gatifloxacin was less active than erythromycin for both species. (+info)
Impairment of natural killer cell activity in Chlamydia trachomatis infected individuals.
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Natural killer (NK) cell activity is impaired in Chlamydia trachomatis-infected patients. The mechanisms behind the altered NK functions are not clear, but data concerning NK and antibody-dependent cellular cytotoxicity (ADCC) activity have been reported. To investigate whether this impairment is related to a defect at the target cell binding and/or the postbinding level, we evaluated highly purified NK cells obtained from 125 C. trachomatis-infected patients and compared them with 101 normal controls for their ability to kill K-562 and U-937 cell lines using a 51Cr release assay; release tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma); and kill anti-IgM preincubated P-815 cell line (ADCC activity). We found a decrease in the lytic capability of NK cells from C. trachomatis-infected patients against target cell lines; decreased ability to kill bound target cells; and low levels of released TNF-alpha and INF-gamma after incubation with U-937 cells. Taken together, these findings suggest that the impaired NK cell reaction during chlamydial infection is related to defects both at the target and postbinding levels. However, the precise mechanisms remain to be determined. The inability to restore normal NK activity after long-term culture in the presence of high levels of recombinant IL-2 support the hypothesis of an anergic process during chlamydial infection. (+info)
The intercellular adhesion molecule type-1 is required for rapid activation of T helper type 1 lymphocytes that control early acute phase of genital chlamydial infection in mice.
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Recent studies in animal models of genital chlamydial disease revealed that early recruitment of dendritic cells and specific T helper type-1 (Th1) cells into the genital mucosae is crucial for reducing the severity of the acute phase of a cervico-vaginal infection and arresting ascending disease. These immune effectors are therefore important for preventing major complications of genital chlamydial infection. Other in vitro studies showed that intercellular adhesion molecule-1 (ICAM-1) plays a role in the antichlamydial action of specific CD4+ and CD8+ T cells. In the present study, we investigated the clinicopathological consequences of ICAM-1 deficiency during chlamydial genital infection in ICAM-1 knockout (ICAM-1KO) mice, and analysed the cellular and molecular immunological bases for any observed pathology or complication. Following a primary genital infection of female ICAM-l-/- and ICAM-1+/+ mice, the intensity of the disease during the first 3 weeks (as assessed by shedding of chlamydiae in the genital tract) was significantly greater in ICAM-1KO mice than in ICAM-1+/+ mice (P < 0.0001), although both ICAM-l-/- and ICAM-1+/+ mice subsequently cleared the primary infection. There was greater ascending disease during the initial stage of the infection, and a higher incidence of tubal disease (hydrosalpinx formation) after multiple infections in ICAM-l-/- mice. Analysis of the cellular and molecular bases for the increased acute and ascending disease in ICAM-l-/- mice revealed that the high affinity of ICAM-1 for leucocyte function antigen type-1 is a property that promotes rapid activation of specific Th1 cells, as well as their early recruitment into the genital mucosa. Moreover, ICAM-1 was more important for naive T-cell activation than primed Th1 cells, although its absence delayed or suppressed immune T-cell activation by at least 50%. Taken together, these results indicated that ICAM-1 is crucial for rapid T-cell activation, early recruitment and control of genitally acquired Chlamydia trachomatis. (+info)
Screening for Chlamydia trachomatis in subfertile women.
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Chlamydia trachomatis is the most common sexually transmitted disease in the UK and Europe. The majority of female infections are asymptomatic and recognized sequelae include pelvic inflammatory disease, infertility, and ectopic pregnancy. Women with chlamydial infection who undergo uterine instrumentation are recognized to be at risk of ascending infection. Most patients attending for infertility investigations and treatment will undergo some form of uterine instrumentation. Published data regarding the prevalence of chlamydial infection in the subfertile are few and conflicting. In this study, more than 400 consecutive women presenting for infertility investigation and treatment at a single regional fertility centre were screened for Chlamydia: Half were screened using enzyme immunoassay (EIA) and half by ligase chain reaction (LCR). Prevalence by diagnostic test was 0% with EIA and 1.9% with LCR. Overall, the low prevalence was at least partly explained by older age. Until more evidence comes from studies testing consecutive subfertile patients both with EIA and a DNA amplification method such as LCR, centres using EIA should consider using prophylactic antibiotics prior to uterine instrumentation. (+info)
Subclinical chlamydial infection of the female mouse genital tract generates a potent protective immune response: implications for development of live attenuated chlamydial vaccine strains.
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Chlamydia trachomatis is a major cause of sexually transmitted disease (STD) for which a vaccine is needed. CD4(+) T-helper type 1 (Th1) cell-mediated immunity is an important component of protective immunity against murine chlamydial genital infection. Conventional vaccine approaches have not proven effective in eliciting chlamydial-specific CD4 Th1 immunity at the genital mucosa. Thus, it is possible that the development of a highly efficacious vaccine against genital infection will depend on the generation of a live attenuated C. trachomatis vaccine. Attenuated strains of C. trachomatis do not exist, so their potential utility as vaccines cannot be tested in animal models of infection. We have developed a surrogate model to study the effect of chlamydial attenuation on infection and immunity of the female genital tract by treating mice with a subchlamydiacidal concentration of oxytetracycline following vaginal infection. Compared to untreated control mice, antibiotic-treated mice shed significantly fewer infectious organisms (3 log(10)) from the cervico-vagina, produced a minimal inflammatory response in urogenital tissue, and did not experience infection-related sequelae. Antibiotic-treated mice generated levels of chlamydia-specific antibody and cell-mediated immunity equivalent to those of control mice. Importantly, antibiotic-treated mice were found to be as immune as control untreated mice when rechallenged vaginally. These findings demonstrate that subclinical chlamydial infection of the murine female genital tract is sufficient to stimulate a potent protective immune response. They also present indirect evidence supporting the possible use of live attenuated chlamydial organisms in the development of vaccines against chlamydial STDs. (+info)