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PubMed1992

Proposal of Chlamydia pecorum sp. nov. for Chlamydia strains derived from ruminants.

Chlamydia pecorum sp. nov. is proposed as the fourth species of the genus Chlamydia on the basis of the results of a genetic analysis of Chlamydia strains that were isolated from cattle and sheep which had various diseases, including sporadic encephalitis, infectious polyarthritis, pneumonia, and diarrhea. The levels of DNA-DNA homology between C. pecorum and strains of C. psittaci, Chlamydia pneumoniae, and Chlamydia trachomatis were less than 10%. Several DNA probes were used to identify C. pecorum. The C. pecorum strains were distinguished from C. psittaci strains by the results of immunological assays, including an immunofluorescence antibody assay performed with monoclonal antibodies and an immunoblot analysis of the immunological specificity of the major outer membrane protein. Species identification was based on results obtained from DNA analyses and serology. The type strain of C. pecorum is strain ATCC VR628.

Animals↗
PubMed1997

Polymerase chain reaction (PCR) detection of porcine Chlamydia trachomatis and ruminant Chlamydia psittaci serovar 1 DNA in formalin-fixed intestinal specimens from swine.

In previous studies chlamydiae were detected immunohistologically in the gut of 66 out of 311 pigs. The aim of the present investigation was the classification of these intestinal porcine chlamydiae. For the study, DNA extracted from 52 paraffin-embedded intestinal tissues was amplified in nested polymerase chain reactions (PCRs) with Chlamydia omp1 genus- and species-specific primers. Some of the amplification products were cloned and sequenced. In 45 cases DNA could be amplified with genus-specific primers. Species-specific PCR and sequencing showed that in 42 cases the chlamydial omp1 genotype was Chlamydia trachomatis. Sequenced DNA fragments were 95-99% identical with the porcine strain S45. In three further cases sequencing analysis provided DNA sequences which were 100% identical with Chlamydia psittaci B577 (serovar 1) omp1 genotype. So far as the authors are aware this is the first report on the occurrence of C. psittaci serovar 1 in pigs.

Animals↗
PubMed2002

Inhibition of apoptosis by gamma interferon in cells and mice infected with Chlamydia muridarum (the mouse pneumonitis strain of Chlamydia trachomatis).

The effect of gamma interferon (IFN-gamma) on apoptosis due to infection by Chlamydia muridarum (the mouse pneumonitis strain of Chlamydia trachomatis) was studied in epithelial cells in culture and in the genital tracts of mice. IFN-gamma concentrations that induce the formation of aberrant, persistent chlamydiae inhibit apoptosis due to C. muridarum infection. In cells treated with an IFN-gamma concentration that leads to the development of a heterogenous population of normal and aberrant Chlamydia vacuoles, apoptosis was inhibited preferentially in cells that contained the aberrant vacuoles. The inhibitory effect of IFN-gamma appears to be due in part to expression of host cell indoleamine 2,3-dioxygenase activity, since inhibition of apoptosis could be partially reversed through coincubation with exogenous tryptophan. Apoptotic cells were observed in the genital tracts of wild-type mice infected with C. muridarum, and a significantly larger number of apoptotic cells was detected in infected IFN-gamma-deficient mice. These results suggest that IFN-gamma may contribute to pathogenesis of persistent Chlamydia infections in vivo by preventing apoptosis of infected cells.

Animals↗
PubMed1991

Comparison of the Clearview Chlamydia test, Chlamydiazyme, and cell culture for detection of Chlamydia trachomatis in women with a low prevalence of infection.

Two antigen detection systems, Clearview Chlamydia (Unipath Ltd., Bedford, United Kingdom) and Chlamydiazyme (Abbott Laboratories, North Chicago, Ill.), were compared with culture for the diagnosis of chlamydia infection in women attending gynecological clinics. Chlamydia trachomatis was isolated from 43 (4.5%) of the 965 women tested. In comparison with tissue culture, the Clearview Chlamydia and Chlamydiazyme tests had sensitivities of 79.0 and 74.4%, respectively, and both had a specificity of 99.6%. The results show that the Clearview Chlamydia test is comparable to Chlamydiazyme for the detection of C. trachomatis from endocervical specimens in a population with a low prevalence of infection.

Adolescent↗
PubMed2005

Discordance between trends in chlamydia notifications and hospital admission rates for chlamydia related diseases in New South Wales, Australia.

BACKGROUND: In Australia, notification rates for chlamydia have increased fourfold since the early 1990s. An increasing incidence of genital Chlamydia trachomatis infection would be expected to lead to a rise in the incidence of chlamydia related diseases. OBJECTIVES: To determine trends in hospital admission rates for pelvic inflammatory disease (PID), ectopic pregnancy, and epididymo-orchitis in New South Wales. METHODS: Age specific admission rates from 1992 to 2001 were ascertained using inpatient data from all hospitals within the state. RESULTS: Among women aged 15-34 years, hospital admission rates for PID fell from 165 per 100,000 population in 1992 to 64 per 100,000 population in 2001 (p for trend<0.0001). 15% of PID cases in women aged 15-24 years were chronic, compared with 32% in those aged 25-34 years, and 46% in the 35-44 year age group. The incidence of ectopic pregnancy and admission rates for epididymo-orchitis remained constant. CONCLUSIONS: On a population level, trends in the incidence of chlamydia related diseases do not necessarily parallel those of reported chlamydia rates and ecological associations between the two need to be interpreted with caution.

Acute Disease↗
PubMed2006

Simplifying chlamydia testing: an innovative Chlamydia trachomatis testing approach using the internet and a home sampling strategy: population based study.

OBJECTIVES: To measure the coverage, gender distribution, and participants' prevalence of genital Chlamydia trachomatis infections using a new internet based self selective testing approach by means of home sampling in the general population in Sweden. To investigate factors associated with these measures. METHODS: Observational survey of people actively ordering coded testing packages, and checking their test results, from a known website. No personal invitations were sent out. All inhabitants (256 885 men and women) in a Swedish county were eligible to participate. A special interest was taken in coverage, gender distribution, participants' chlamydia prevalence, and determinants for infection. RESULTS: Testing was highest in the age group 20-24 years, where 298/9495 (3.1%) of all women and 171/9574 (1.8%) of all men in the population participated. The overall population participation (all ages) was 906/256 885 (0.4%). 40% (364/906) of the tests were from men and 60% (542/906) from women. The prevalence of Chlamydia trachomatis infection was 6.0% (95% CI: 3.6% to 8.4%) among male participants and 4.6% (95% CI: 2.8% to 6.4%) among female participants. Prevalence increased with decreasing age. Believing to be infected and having symptoms were the strongest determinants of infection. CONCLUSION: Simplifying and increasing the accessibility of chlamydia testing by means of internet and home sampling proved feasible. Self risk assessment improves the chance of finding people infected by Chlamydia trachomatis, especially among men, if an accessible testing method is offered. This new method can serve as a supplement to regular preventive methods and might encourage young people to be tested.

Adolescent↗
PubMed2004

Re-infection of Chlamydia trachomatis in patients presenting to the genitourinary medicine clinic in Portsmouth: the chlamydia screening pilot study - three years on.

Chlamydia trachomatis is the most common bacterial sexually transmitted infection (STI) in the UK. The Department of Health set up an opportunistic screening programme for genital chlamydia infection, focusing on sexually active 16-24-year-old women and some men. This study identified those patients re-attending the genitourinary medicine (GUM) clinic and followed them up until September 2002. We examined the reasons for attendance and re-infection with chlamydia. Two hundred and eighty-five patients re-attended the clinic. Two-thirds of these had changed their sexual partners in the follow-up period. Fifty-six patients were diagnosed with genital chlamydia infection in subsequent clinic visits. The majority of them had changed their sexual partners, suggesting new acquisition of infection. This suggests that in this age group re-screening should be offered at a year interval. Patients diagnosed with genital chlamydia infection should be referred to the GUM clinic for further STI screening and partner notification.

Adolescent↗
PubMed1989

[The usefulness of Chlamydia testpack for the diagnosis of Chlamydia trachomatis infection in genito-urinary tract].

A comparative study between Chlamydia Testpack and Chlamydiazyme for the detection of chlamydial antigen was performed. In 61 cases suspected of being chlamydial infection, Chlamydia Testpack had a specificity of 92% and a sensitivity of 88% when compared with Chlamydiazyme. On the result of study using Chlamydia trachomatis serotype B, the sensitivity of Chlamydia Testpack which had a lower limit of 6 x 10(4)/ml of EB was less than that of Chlamydiazyme which had a lower limit of 0.7 x 10(4). However, the large number of EB presented in almost all positive specimen, indicated that Chlamydia Testpack could be used to screen the clinical materials.

Adolescent↗
PubMed1994

[The prevalence of anti-Chlamydia trachomatis and anti-Chlamydia pneumoniae antibodies in Brazzaville].

The prevalence study of antibodies to Chlamydia trachomatis and Chlamydia pneumoniae in Brazzaville were screened from 108 women (56 pregnant women, 18 infertile women and 34 women affected with genital tract infections) and 108 blood donors (control subjects) by indirect microimmunofluorescent assay. 57.4% of studied women were carrying Chlamydia trachomatis antibodies, and 51.8% had C. pneumoniae antibodies. Prevalence of Chlamydia antibodies by women group studied was estimated to be: in pregnancy women group 51.7% of C. trachomatis antibodies and 62.5% of C. pneumoniae antibodies; in infertile women group 61.1% of C. trachomatis antibodies and 33.3% of C. pneumoniae antibodies; in women affected with genital tract infections group: 64.7% of C. trachomatis antibodies and 44.1% of C. pneumoniae antibodies. In blood donors group, the prevalence of IgG antibodies against Chlamydia trachomatis is 27.7% and 37% for IgG antibodies against C. pneumoniae.

Adolescent↗
PubMed1989

Ultrastructural studies on the intracellular fate of Chlamydia psittaci (strain guinea pig inclusion conjunctivitis) and Chlamydia trachomatis (strain lymphogranuloma venereum 434): modulation of intracellular events and relationship with endocytic mechanism.

Previous observations on the highly infectious LGV strain 434 of Chlamydia trachomatis and the guinea pig inclusion conjunctivitis (GPIC) strain of C. psittaci (which requires centrifugation of inocula with host cell monolayers for maximum infectivity) indicated that infectivity differences were expressed, not at entry, but at an intracellular stage affecting multiplication. Centrifugation increased the potential of internalized chlamydiae to undergo productive infection. Here, analysis of the intracellular fate of chlamydiae by ultrastructural methods indicates that strain GPIC exhibits two patterns of behaviour depending on the mode of inoculation. Strain GPIC showed limited entry, with 47% of intracellular organisms becoming associated with thorotrast-labelled lysosomes, following static incubation with monolayers. In contrast, with centrifugation, entry was not limited and association with lysosomes was reduced to 12%; strain 434 behaved similarly but independently of the mode of inoculation. The different results for strain GPIC correlated with distinct entry mechanisms. Entry during static incubation was unimpaired either by treatment with cytochalasin D or by temperature reduction to 20 degrees C, suggesting that it was pinocytic. Entry during centrifugation was markedly impaired by both treatments, suggesting that it was phagocytic. The data lead to two novel conclusions: first, that chlamydiae can apparently enter cells by both pinocytic and phagocytic mechanisms; second, that the entry mechanism influences intracellular fate. It is suggested that entry mechanism is linked to selection of the vesicle membrane forming around the internalizing chlamydiae. This, in turn, may influence both intracellular translocation and subsequent inhibition or promotion of multiplication of the internalized parasite.

Animals↗
PubMed1978

Parasite-specified phagocytosis of Chlamydia psittaci and Chlamydia trachomatis by L and HeLa cells.

Phagocytosis of the 6BC strain of Chlamydia psittaci and the lymphogranuloma venereum 440L strain of Chlamydia trachomatis by L cells and HeLa 229 cells occurred at rates and to extents that were 10 to 100 times greater than those observed for the phagocytosis of Escherichia coli and polystyrene latex spheres. Both species of Chlamydia were efficiently taken up by host cells of a type they had not previously encountered. Phagocytosis of chlamydiae was brought about by the interaction of parasite surface ligands with elements of the host cell surface. The chlamydial ligands were readily denatured by heat, were masked by antibody, and were resistant to proteases and detergents. The host cell components were reversibly removed by proteases. Chlamydial phagocytosis was inhibited when host cells were incubated for many hours with cycloheximide. It was suggested that the presence on the chlamydial cell surface of ligands with high affinity for normal, ubiquitously occurring structures on the surface of host cells is an evolutionary adaptation to intracellular existence. The term parasite-specified phagocytosis was used to describe the efficient phagocytosis of chlamydiae by nonprofessional phagocytes and to distinguish it from the host-specified immunological and non-immunological phagocytosis carried out by professional phagocytes.

Chlamydia trachomatis↗
PubMed1985

Synthesis of protein in host-free reticulate bodies of Chlamydia psittaci and Chlamydia trachomatis.

Synthesis of protein by the obligate intracellular parasitic bacteria Chlamydia psittaci (6BC) and Chlamydia trachomatis (serovar L2) isolated from host cells (host-free chlamydiae) was demonstrated for the first time. Incorporation of [35S]methionine and [35S]cysteine into trichloroacetic acid-precipitable material by reticulate bodies of chlamydiae persisted for 2 h and was dependent upon a exogenous source of ATP, an ATP-regenerating system, and potassium or sodium ions. Magnesium ions and amino acids stimulated synthesis; chloramphenicol, rifampin, oligomycin, and carbonyl cyanide p-trifluoromethoxyphenylhydrazone (a proton ionophore) inhibited incorporation. Ribonucleoside triphosphates (other than ATP) had little stimulatory effect. The optimum pH for host-free synthesis was between 7.0 and 7.5. The molecular weights of proteins synthesized by host-free reticulate bodies closely resembled the molecular weights of proteins synthesized by reticulate bodies in an intracellular environment, and included outer membrane proteins. Elementary bodies of chlamydiae were unable to synthesize protein even when incubated in the presence of 10 mM dithiothreitol, a reducing agent which converted the highly disulfide bond cross-linked major outer membrane protein to monomeric form.

Bacterial Outer Membrane Proteins↗
PubMed1979

[The replication cycle of Chlamydia trachomatis and Chlamydia psittaci: ultrastructural analysis].

An ultrastructural comparative analysis is reported on the replication cycle of six strains of Chlamydia trachomatis, recently isolated, and Chlamydia psittaci strain 6BC, grown in cell cultures. Important morphological distinctions of the bacterial walls are documented. In Chlamydia trachomatis the cell wall seems more rigid. This causes, during the morphogenesis of the elementary body, its separation from the cell membrane with formation of an electron transparent space, which is not demonstrable in Chlamydia psittaci. As a result of this process, the appearance of "ghosts" and "mini reticular bodies" is documented. Budding and multiple fission are suggested as possible mechanisms of replication of Chlamydia trachomatis, in coexistence or/as alternative to binary fission.

Cell Wall↗
PubMed2006

Does population screening for Chlamydia trachomatis raise anxiety among those tested? Findings from a population based chlamydia screening study.

BACKGROUND: The advent of urine testing for Chlamydia trachomatis has raised the possibility of large-scale screening for this sexually transmitted infection, which is now the most common in the United Kingdom. The purpose of this study was to investigate the effect of an invitation to be screened for chlamydia and of receiving a negative result on levels of anxiety, depression and self-esteem. METHODS: 19,773 men and women aged 16 to 39 years, selected at random from 27 general practices in two large city areas (Bristol and Birmingham) were invited by post to send home-collected urine samples or vulvo-vaginal swabs for chlamydia testing. Questionnaires enquiring about anxiety, depression and self-esteem were sent to random samples of those offered screening: one month before the dispatch of invitations; when participants returned samples; and after receiving a negative result. RESULTS: Home screening was associated with an overall reduction in anxiety scores. An invitation to participate did not increase anxiety levels. Anxiety scores in men were lower after receiving the invitation than at baseline. Amongst women anxiety was reduced after receipt of negative test results. Neither depression nor self-esteem scores were affected by screening. CONCLUSION: Postal screening for chlamydia does not appear to have a negative impact on overall psychological well-being and can lead to a decrease in anxiety levels among respondents. There is, however, a clear difference between men and women in when this reduction occurs.

Adolescent↗
PubMed1997

Mixed infections with porcine Chlamydia trachomatis/pecorum and infections with ruminant Chlamydia psittaci serovar 1 associated with abortions in swine.

In a previous immunohistological study, chlamydiae were detected in 5 out of 139 cases of swine abortion, and a possible implication of C. psittaci serovar 1 was suggested. The present study sought to classify the chlamydiae found in the fetal organs of these abortions. DNA extracted from 15 paraffin-embedded tissue specimens (10 livers and 5 lungs, obtained from 10 fetuses from 9 cases of abortion) was amplified in a nested PCR with Chlamydia omp1 genus-specific primers. Chlamydia DNA was amplified in 9 liver and 2 lung specimens. Eight of the amplification products were cloned, and 5 clones of each amplification were sequenced. Sequence analysis demonstrated in 7 specimens the simultaneous presence of porcine C. trachomatis S45 and C. pecorum 1710S omp1 genotypes. All DNA fragments of 1 amplification were identical to the ruminant C. psittaci B577 omp1 genotype (serovar 1). The results suggest that mixed infections with porcine C. trachomatis and C. pecorum dominate chlamydial infections associated with abortion in swine, but ruminant abortigenic C. psittaci are also found.

Abortion, Veterinary↗
PubMed1993

Comparison of serological tests for the detection of antibodies against Chlamydia trachomatis and Chlamydia pneumoniae in rheumatological patients.

In cases of reactive arthritis, a suspected Chlamydia trachomatis infection is often detected by serological methods. However, mostly tests with genus-specific antigens are used, neglecting the fact that antibodies against Chlamydia pneumoniae are highly prevalent in the adult population. Therefore we tested sera of 129 patients with various rheumatological disorders and of 18 healthy persons in parallel with a genus-specific test (IPAZYME) and with the species-specific microimmunofluorescence test for C. trachomatis and C. pneumoniae antibodies. The data showed that 55% of the 64 IPA-positive results were caused by antibodies (IgG) against Chlamydia pneumoniae, only 6% by anti-Chlamydia trachomatis IgG and 20% by both specificities. For IgA antibodies, the percentages were 44%, 12.5% and 12.5% respectively. In 12 IPA-positive cases, the MIF showed no reaction. 58% of all 147 sera tested with MIF had IgG antibodies against C. pneumoniae, 5% had anti-C. trachomatis IgG and 8% IgG against both species. The percentages for IgA were 29%, 2% and 2%, respectively. IgM positivity in MIF disappeared after absorption with rheumatoid factor absorbent. No significant differences were found between the various groups of patients. The data suggest that due to the high prevalence of anti-C. pneumoniae antibody, genus-species tests cannot be used as screening tests for the serological diagnosis of C. trachomatis infections.

Adolescent↗
PubMed1996

The value of isotype determination of serum antibodies against Chlamydia for the diagnosis of Chlamydia reactive arthritis.

In clinical rheumatology, the diagnosis of Chlamydia reactive arthritis is difficult because an incomplete form of the disease can closely resemble an undifferentiated seronegative mono/oligoarthritis. We investigated whether measuring specific isotypes of anti-Chlamydia antibodies in serum can improve the diagnosis, by comparing such antibody concentrations in the serum of patients with well-defined disease, i.e. Chlamydia trachomatis sexually acquired reactive arthritis (CT-SARA), with other arthritides. Antibody levels were determined by enzyme-linked immunosorbent assay (ELISA). When considering two different isotypes and their combination, the best sensitivity (63%) was obtained for IgM and/or IgA results with a specificity of 81%. The patients with CT-SARA and SARA had the highest levels of antibodies of all isotypes tested. It is concluded that, in our experimental conditions, only very high values of specific isotypes could indicate a diagnosis of Chlamydia reactive arthritis.

Adolescent↗
PubMed1991

[Prevalence of antibodies to Chlamydia pneumoniae (strain TWAR) and other Chlamydia in Japan].

Chlamydia pneumoniae (Strain TWAR), the new third species of genus Chlamydia, is emerging as an important human respiratory pathogen in Western countries. However, little is known about it in Japan. In this study, 1330 serum samples were tested for seroprevalence of three species of genus Chlamydia including C. pneumoniae in Hiroshima. Microimmunofluorescence test was used to measure serum IgG antibody, and formalin fixed elementary bodies of C. trachomatis, C. psittaci, and C. pneumoniae were used as antigen. Serum titer of 1:32 or greater was considered positive. Seropositive rate of C. pneumoniae began to increase around the 6 month to 3 year old age group and reached 44% in the 8 to 11 year olds. A peak of seroprevalence according to age was around 20 year old, and about half of the adults were seropositive. Outpatients and healthy persons held almost the same seropositive rate. The positive rate in childhood was higher and the peak appeared earlier than some former studies in Western countries. The seropositive rate of C. trachomatis was noted 1-2% in the 6 month-7 year old age group, but no seropositive child was found in the 8-15 year olds. The rate was increased after adolescence and reached 10% in adults. The seroprevalence of C. psittaci was 1%. These data suggest C. pneumoniae is the most prevalent Chlamydia in Japan and as prevalent as in the Western countries.

Adolescent↗