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PubMed2003

Chlamydia infection in children with acquired subglottic stenosis.

The purpose of the study was to find out the frequency of occurrence and the role of Chlamydia infection in the pathogenesis of acquired subglottic stenosis in children. Forty-nine patients of the age from 1 year 10 months to 15 years with acquired cicatricial laryngotracheal stenosis were examined. The immunofluorescent method was used to detect serum antibodies to the antigens of Chlamydia trachomatis and Chlamydia pneumoniae. Dilutions of 1:32 for C. trachomatis and 1:64 for C. pneumoniae were considered positive. The results of the study suggested both a high frequency (26.5%) of Chlamydia infection (C. pneumoniae) of the children with acquired subglottic stenosis, as well as 92% of infected children were either with tracheotomies or had been decannulated earlier. It reasonable to test children with a tracheostomy for the presence of Chlamydia infection to perform timely and specific antibiotic therapy.

Adolescent↗
PubMed1999

[Chlamydia trachomatis conjunctivitis in the newborn].

Infections of the conjunctiva are frequent in the neonatal period. While Neisseria gonorrhoea and chemical agents were considered as the main etiologies of ophtalmiae neonatorum in the past, Chlamydia trachomatis is today a major cause of neonatal conjunctivitis. Thus in a study of 180 uni-or bilateral neonatal conjunctivitis the authors found a prevalence of Chlamydia trachomatis infection of 41%. The importance of the etiological diagnosis of neonatal conjunctivitis is emphasized, in order to define a specific treatment. Etiological diagnosis of Chlamydia trachomatis infection is based upon immunofluorescence and molecular diagnosis techniques (PCR, LCR). Prevention of neonatal Chlamydia trachomatis conjunctivitis relies upon screening and treatment of Chlamydia trachomatis infections in pregnant women and their partners. Treatment requires oral macrolides, the topical treatment being ineffective.

Anti-Bacterial Agents↗
PubMed1988

Chlamydia: its influence in chronic secretory otitis media.

Since Chlamydia trachomatis was isolated from middle ear effusions of neonates with natally acquired chlamydial infection (Tipple et al., 1979), there have been several studies to detect chlamydia in older children with chronic secretory otitis media, mainly by tissue culture. In this study, the aspirates of 106 middle ear effusions of 60 children with chronic secretory otitis media were investigated for the presence of C. trachomatis, other bacteria and viruses. An amplified enzyme-linked immunoassay was used to detect the presence of chlamydia. The bacteriological and virological results mirrored previous studies in the United Kingdom and no chlamydia were found. Chlamydia do not appear to be related to the aetiology of this disease in the population examined.

Bacteria↗
PubMed2001

Low iron availability modulates the course of Chlamydia pneumoniae infection.

Chlamydiae are obligate intracellular bacteria residing exclusively in host cell vesicles termed inclusions. We have investigated the effects of deferoxamine mesylate (DAM)-induced iron deficiency on the growth of Chlamydia pneumoniae and Chlamydia trachomatis serovar L2. In epithelial cells subjected to iron starvation and infected with either C. pneumoniae or C. trachomatis L2, small inclusions were formed, and the infectivity of chlamydial progeny was impaired. Moreover, for C. trachomatis L2, we observed a delay in homotypic fusion of inclusions. The inhibitory effects of DAM were reversed by adding exogenous iron-saturated transferrin, which restored the production of infectious chlamydiae. Electron microscopy examination of iron-deprived specimens revealed that the small inclusions contained reduced numbers of C. pneumoniae that were mostly reticulate bodies. We have previously reported specific accumulation of transferrin receptors (TfRs) around C. pneumoniae inclusions within cells grown under normal conditions. Using confocal and electron microscopy, we show here a remarkable increase in the amount of TfRs surrounding the inclusions in iron-starved cultures. It has been shown that iron is an essential factor in the growth and survival of C. trachomatis. Here, we postulate that, for C. pneumoniae also, iron is an indispensable element and that Chlamydia may use iron transport pathways of the host by attracting TfR to the phagosome.

Chlamydia trachomatis↗
PubMed1983

[Gonorrheal urethritis--frequently a mixed Chlamydia and Mycoplasma infection. Results in 143 male patients with acute gonorrhea].

Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis are frequently demonstrated in cases of acute gonorrhoeic urethritis. Among 143 males (average age 22.5 years) Chlamydia was demonstrated in 29%, U. urealyticum in 34% and M. hominis in 13%. Penicillin treatment of gonorrhoea does not affect Chlamydia and Mycoplasma so that these organisms will persist in the lower urogenital tract. Generally postgonorrhoeic urethritis is associated with Chlamydia or Mycoplasma infection. Nearly all patients were cured by tetracyclin or erythromycin administration. Incidence and complications of gonorrhoea co-infected with Chlamydia and Mycoplasma should be taken into account in its diagnosis and treatment.

Adolescent↗
PubMed1995

Lipid metabolism in Chlamydia trachomatis-infected cells: directed trafficking of Golgi-derived sphingolipids to the chlamydial inclusion.

Chlamydia trachomatis undergoes its entire life cycle within an uncharacterized intracellular vesicle that does not fuse with lysosomes. We used a fluorescent Golgi-specific probe, (N-[7-(4-nitrobenzo-2-oxa-1,3-diazole)]) aminocaproylsphingosine (C6-NBD-Cer), in conjunction with conventional fluorescence or confocal microscopy to identify interactions between the Golgi apparatus and the chlamydial inclusion. We observed not only a close physical association between the Golgi apparatus and the chlamydial inclusion but the eventual presence of a metabolite of this fluorescent probe associated with the chlamydiae themselves. Sphingomyelin, endogenously synthesized from C6-NBD-Cer, was specifically transported to the inclusion and incorporated into the cell wall of the intracellular chlamydiae. Incorporation of the fluorescent sphingolipid by chlamydiae was inhibited by brefeldin A. Chlamydiae therefore occupy a vesicle distal to the Golgi apparatus that receives anterograde vesicular traffic from the Golgi normally bound for the plasma membrane. Collectively, the data suggest that the chlamydial inclusion may represent a unique compartment within the trans-Golgi network.

4-Chloro-7-nitrobenzofurazan↗
PubMed2005

Discordant detection of Chlamydia pneumoniae in patients with carotid artery disease using polymerase chain reaction, immunofluorescence microscopy and serological methods.

AIM: To determine the presence of Chlamydia pneumoniae in carotid plaque and peripheral blood mononuclear cells (PBMCs) using a combination of serology, direct antigen detection by immunofluorescence (IF) microscopy and polymerase chain reaction (PCR), and to compare the results obtained from each assay. METHODS: A total of 54 atherosclerotic carotid plaques were tested for the presence of Chlamydia by PCR and IF methods. Of these 54 patients with carotid artery disease (CAD), 43 were also tested for the presence of C. pneumoniae DNA in PBMCs and for Chlamydia antibodies using two methods, the Medac Chlamydien rELISA and Focus Chlamydia microimmunofluorescence (MIF) methods. RESULTS: Eighteen of the 54 (33%) carotid specimens were positive for the presence of C. pneumoniae DNA, whereas only two of 43 (5%) patients had C. pneumoniae DNA present within their PBMC fraction. Chlamydial antibodies were detected by MIF and/or rELISA in 56% (24/43) of the patients tested. None of the 43 patients was C. pneumoniae positive in all of the test specimens (plaque, PBMCs and serum). CONCLUSIONS: Chlamydia pneumoniae is commonly found in Australian patients with CAD. Serology and PCR-based detection of C. pneumoniae in PBMCs and plaque give highly discordant results.

Aged↗
PubMed2004

Chlamydia inhibit host cell apoptosis by degradation of proapoptotic BH3-only proteins.

Chlamydia are obligate intracellular bacteria that replicate in a vacuole inside a host cell. Chlamydial infection has been shown to protect the host cell against apoptotic stimuli. This is likely important for the ability of Chlamydia to reproduce in human cells. Here we show that resistance to apoptosis is conveyed by the destruction of the proapoptotic BH3-only proteins Bim/Bod, Puma, and Bad during infection. Apoptotic stimuli were blocked upstream of the mitochondrial activation of Bax/Bak. During infection with both species, Chlamydia trachomatis and Chlamydia pneumoniae, Bim protein gradually disappeared without noticeable changes in Bim mRNA. The disappearance was blocked by inhibitors of the proteasome. Infected cells retained sensitivity to Bim expressed by transfection, indicating functional relevance of the Bim disappearance. Fusion to Bim targeted the green fluorescent protein for destruction during infection. Analysis of truncation mutants showed that a short region of Bim containing the BH3 domain was sufficient for destruction during chlamydial infection. Like Bim, Puma and Bad proteins disappeared during infection. These results reveal a novel way by which microbes can interfere with the host cell's apoptotic machinery, and provide a molecular explanation of the cellular resistance to apoptosis during infection with Chlamydia.

Apoptosis↗
PubMed2004

Indirect estimation of Chlamydia screening coverage using public health surveillance data.

Although routine screening of all sexually active adolescent females for Chlamydia trachomatis infection is recommended at least annually in the United States, no national or state-specific population-based estimates of chlamydia screening coverage are known to exist. Conclusions regarding screening coverage have often been based on surveys of health care provider or facility screening practices, but such surveys do not consider persons who do not seek care at these facilities or who seek care at more than one facility. The authors developed a method to estimate the proportion of sexually active females aged 15-19 years screened for chlamydia in 45 states and the District of Columbia by using national data on chlamydia positivity, estimates of sexual activity from the National Survey of Family Growth, and chlamydial infections reported to the Centers for Disease Control and Prevention. Because of uncertainty regarding these values and related assumptions, credibility intervals were calculated by using a Monte Carlo model. When this model was used, the median state-specific proportion of sexually active females aged 15-19 years screened in 2000 was 60% (90% credibility interval: 55, 66). These results and this method should be evaluated for their utility in guiding implementation of national and state chlamydia control programs.

Adolescent↗
PubMedDate not supplied

In vitro activity of rifamycins alone and in combination with other antibiotics against Chlamydia trachomatis.

Rifamycins are highly active against Chlamydia trachomatis, but the possible development of resistance has been of concern. The ability of rifampin, rifamide, and DL473 to induce resistance in chlamydiae and the effect of combinations of antibiotics on chlamydiae were evaluated in tissue culture. When chlamydiae were exposed to stepwise increases in the concentration of rifampin or rifamide, resistance rapidly emerged. Stepwise resistance did not emerge after exposure to DL473, although organisms resistant to one rifamycin were resistant to all three. Single-step emergence of resistance to rifampin or DL473 was also demonstrated. However, these resistant organisms were difficult to maintain in tissue culture. Combinations of ampicillin, erythromycin, or a tetracycline with rifampin or DL473 were neither synergistic nor antagonistic against chlamydiae. However, subinhibitory amounts of erythromycin or oxytetracycline prevented the emergence of resistance to rifampin. Such combinations may prove useful in therapy for chlamydial infections.

Chlamydia trachomatis↗
PubMed2002

Atherosclerosis in dialysis patients: does Chlamydia pneumoniae infection contribute to cardiovascular damage?

Cardiovascular risk in the dialysis population is exceedingly high, and there is now convincing evidence that inflammation is strongly linked to atherosclerosis in this population. The source of inflammation in dialysis patients still remains undefined. Bacterial contamination during the extracorporeal circulation and bioincompatibility explain only a very small part of the high prevalence of inflammation [as defined by raised C-reactive protein (CRP)] in these patients. In the general population, several infectious agents have been implicated as likely culprits of atherosclerosis, and Chlamydia pneumoniae is the most suspected. In dialysis patients, the presence of a high titre of anti-C. pneumoniae antibodies is associated with the severity of atherosclerosis. The CREED database (Cardiovascular Risk Extended Evaluation in Dialysis patients) has on file 278 patients tested for C. pneumoniae and followed-up for 4 years. Interestingly, in this database, the risk for cardiovascular death is approximately 4 times higher in the group of patients (n=50) seropositive for Chlamydia and with raised CRP than in those with no evidence of Chlamydia infection and normal CRP. Yet seropositivity to Chlamydia did not significantly increase the risk associated with raised CRP. These data suggest that raised CRP and C. pneumoniae seropositivity is a high risk situation, but it remains very uncertain as to whether Chlamydia infection per se contributes to the high cardiovascular risk of dialysis patients.

Arteriosclerosis↗
PubMed1999

Chlamydia transmission: concurrency, reproduction number, and the epidemic trajectory.

To identify factors that influence individual and group transmission of Chlamydia, the authors conducted community-wide contact tracing of chlamydia cases in Colorado Springs, Colorado, from mid-1996 to mid-1997. Case patients identified persons with whom they had had contact during the 6 months preceding diagnosis; contacts were actively sought and offered DNA amplification testing. Sexual contact networks were used to identify "source cases" and "spread cases," permitting estimation of the basic reproduction number (R0) for individuals and groups. Network and epidemiologic factors influencing R0 were assessed using univariate and multivariate procedures. Of 1,309 case patients, 1,131 (86%) were interviewed, and 2,409 contacts were identified. The 1,131 interviewed cases yielded 623.9 computed spread cases, for an overall R0 of 0.55. Few subgroups analyzed yielded a mean R0 exceeding unity-an observation in keeping with routine surveillance information which suggests that chlamydia incidence is declining in Colorado Springs. Concurrency, a network measure of simultaneous partnerships, was the most powerful predictor of transmission. Direct estimation of basic reproduction numbers for chlamydia using contact tracing techniques is feasible and can produce useful data with which to prioritize control efforts, evaluate interventions, and gauge the place of chlamydia on the epidemic continuum.

Adolescent↗
PubMed1999

Chlamydia pneumoniae as a triggering infection in reactive arthritis.

OBJECTIVE: To determine the role of Chlamydia pneumoniae as a triggering infection in reactive arthritis (ReA). METHODS: Sixty patients with acute arthritis were screened for the evidence of triggering infections. In all patients, bacterial stool cultures, culture of Chlamydia trachomatis in urethra/cervix, and/or bacterial serology were studied. Chlamydia pneumoniae antibodies were measured by specific microimmunofluorescence test. RESULTS: Thirty-five of 60 patients fulfilled the diagnostic criteria for ReA. Thirty-one patients had microbial/serological evidence of preceding infection due to Salmonella, Yersinia, Campylobacter or Chlamydia trachomatis, or they had enteritis or urethritis prior to arthritis. Four additional patients had high antibody titre for C. pneumoniae. Three of these four patients had preceding lower respiratory symptoms, and were positive for HLA-B27. The clinical picture of C. pneumoniae-positive ReA patients was similar to that of ReA patients with other definite aetiology. CONCLUSION: Chlamydia pneumoniae is a triggering factor in approximately 10% of patients with acute ReA.

Adult↗
PubMed2000

Evaluation of chlamydia and gonorrhea screening criteria: San Francisco sexually transmitted disease clinic: 1997 to 1998.

BACKGROUND AND OBJECTIVES: The advent of more sensitive diagnostic testing technologies and competition in public healthcare spending have resulted in a reevaluation of sexually transmitted disease (STD) screening practices in an attempt to target populations at greatest risk. Screening among populations with a < 2% prevalence of chlamydia and a < 1% prevalence of gonorrhea may not be cost-effective. GOAL: To identify subpopulations with a low prevalence of chlamydia or gonorrhea. STUDY DESIGN: The prevalence of genital chlamydia and gonorrhea among asymptomatic STD patients screened from 1997 to 1998 at San Francisco City Clinic was stratified by demographic and behavioral risk factors. RESULTS: The prevalence of chlamydia and gonorrhea was 3.4% and 1.1% among asymptomatic women and 4.0% and 1.0% among asymptomatic men, respectively. Two low-prevalence subpopulations identified among asymptomatic patients were women older than 29 years (chlamydia, 1.2%) and men who have sex with women (gonorrhea, 0.8%). CONCLUSIONS: These data identified low-prevalence subpopulations among asymptomatic STD patients. As a result, the STD screening criteria at San Francisco City Clinic were changed accordingly.

Adolescent↗
PubMed2002

Cost-effectiveness of five strategies for gonorrhea and chlamydia control among female and male emergency department patients.

BACKGROUND: Previous studies have shown screening for gonorrhea and chlamydia to be cost-effective for limiting the sequelae of infection and the associated costs of management. GOAL: To evaluate the cost-effectiveness of enhanced screening for gonorrhea and chlamydia in an emergency department (ED) setting. STUDY DESIGN: Five strategies were compared with use of decision analysis for theoretical cohorts of 10,000 female and 10,000 male ED patients aged 18 years to 31 years: standard ED practice, three enhanced screening strategies, and mass treatment. Main outcome measures were untreated gonorrhea or chlamydia cases and their sequelae, transmission to a partner, congenital outcomes, and cost to prevent a case. This analysis, from the perspective of the healthcare sector, included medical case costs expressed in US dollars (1999), discounted at an annual rate of 3%. RESULTS: Mass treatment was the most cost-effective strategy among women and men. Of the screening strategies for women, universal screening combined with standard practice was the most cost-effective; it was used for treating 499 more cases of gonorrhea and chlamydia than was standard practice, saving $95.70 per case treated. Standard ED practice remained the most cost-effective strategy for men under a variety of circumstances. CONCLUSION: The authors recommend urine ligase chain reaction screening for gonorrhea and chlamydia in women aged 18 years to 31 years in the ED, in conjunction with standard ED practice, to decrease the occurrence of the sequelae and costs associated with infection.

Adolescent↗
PubMed1989

Adherence of multiple serovars of Chlamydia trachomatis to a common receptor on HeLa and McCoy cells is mediated by thermolabile protein(s).

Several aspects of the adherence of purified elementary bodies (EB) of Chlamydia trachomatis to HeLa and to McCoy cells were examined using different techniques, including an ELISA. Serovar-specific, biotinylated monoclonal antibodies were used to detect cell-bound chlamydiae. In addition, purified chlamydiae were biotinylated and their adherence properties were studied. The assays were done at 4 degrees C to exclude the energy-dependent internalization of the cell-bound EB and host-cell membrane recycling that occur at 37 degrees C. Saturation kinetics were routinely observed at 4 degrees C, and the rate of adherence remained linear for approximately 60 min. Lineweaver-Burk analysis of the kinetics data showed that adherence of any one serovar was competitively inhibited by other serovars of C. trachomatis. This competition for the same receptor on the two alternative hosts, HeLa and McCoy, was also seen when the adherence assays were done at 37 degrees C in the presence of sodium azide, an energy poison that inhibits endocytosis of cell-bound chlamydiae. Chlamydiae exposed to 56 degrees C for 5 min, or treated with low doses of trypsin, failed to exhibit competitive inhibition, having suffered considerable loss of the ability to adhere to host-cells. These data suggest that heat- and trypsin-labile chlamydial moieties participate in the adherence reaction, and that oculo-genital serovars of C. trachomatis, including that of lymphogranuloma venereum, attach to the same receptor on the host-cell membrane.

Azides↗
PubMed1997

Diagnosis of Chlamydia pneumoniae infection in patients with chronic obstructive pulmonary disease by micro-immunofluorescence and ELISA.

The incidence of Chlamydia pneumoniae infection was determined in patients with chronic obstructive pulmonary diseases (COPD) by prospective serial serology. Chlamydia-specific IgG, IgM and IgA antibodies were detected with a recombinant DNA lipopolysaccharide (LPS) ELISA as well as with a micro-immunofluorescence (MIF) assay with C. pneumoniae elementary bodies. From 271 consecutive COPD patients who visited the outpatient clinic of the department of pulmonary diseases (211 males, 60 females, age range 34-88 years, mean age 66 SD 10 years), blood samples (n = 1058) were taken every 2-7 months; the observation period ranged from 3 to 19 months (mean 15 SD 4). The prevalence of chlamydial IgG was 72% with the MIF and 53% with the rDNA LPS ELISA. More than 90% of the COPD patients had no significant changes in their chlamydia-specific IgG, IgA and IgM titres in either test during the observation period. Seven (3%) patients had MIF results indicating acute C. pneumoniae infection during their surveillance period, of whom five were confirmed by rDNA LPS ELISA. Eleven (4%) additional patients were infected during observation, as determined by rDNA LPS ELISA only. These patients had significantly elevated C. pneumoniae-specific IgG and IgA MIF titres, as compared with the patients without infection. All 18 patients with serological evidence of acute infection during their surveillance period were re-tested in a commercial MIF test that can distinguish between C. pneumoniae, C. trachomatis and C. psittaci LPS-specific antibodies, but no evidence of C. trachomatis or C. psittaci infection was found. The incidence of chlamydial infection was 2.2 and 5.3/100 person-years, when diagnosed by MIF and rDNA LPS ELISA, respectively. It is concluded that the rDNA LPS chlamydia assay may currently be the most sensitive serological tool for diagnosing recent respiratory chlamydia infections and that C. pneumoniae infection occurs frequently in COPD patients.

Adult↗
PubMed1997

Widely used, commercially available Chlamydia pneumoniae antigen contaminated with mycoplasma.

Mycoplasma contamination was detected in a widely used commercially available Chlamydia pneumoniae antigen preparation. Contamination was studied with a mycoplasma group-specific 16S rRNA polymerase chain reaction (PCR) and sequence analysis. Several lots of the purified C. pneumoniae antigen from the Washington Research Foundation appeared to be contaminated with the same Mycoplasma species, which appeared to be closely related to M. arginini. Antigen slides prepared for the detection of chlamydia antibodies by MRL Diagnostics were contaminated with the same Mycoplasma sp. Chlamydia antigen slides from Labsystems OY and two chlamydia complement fixation reagents (Virion International Distribution Ltd and Behring Werke) were not contaminated. It is concluded that commercially available C. pneumoniae antigens may contain mycoplasma antigens as well. Although the impact of such mycoplasma contamination on the results of chlamydia serology may not be significant, routine screening of all antigen preparations obtained by tissue culture before their distribution and use is recommended.

Antibodies, Bacterial↗