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PubMed2001

Application of blood-based polymerase chain reaction for detection of Chlamydia pneumoniae in acute respiratory tract infections.

The aim of this study was to investigate whether blood-based polymerase chain reaction could serve as a diagnostic tool to identify individuals with acute respiratory Chlamydia pneumoniae infection. Respiratory specimens and peripheral blood mononuclear cells of 58 patients were analyzed using nested polymerase chain reaction and cell culture. Fifteen patients were polymerase chain reaction-positive for Chlamydia pneumoniae. Nine patients were positive in only the respiratory specimen; two in both the respiratory and blood sample (time intervals between onset of symptoms and sample collection, 3-10 days and 3-4 weeks, respectively); and four in only the blood sample. Detection of Chlamydia pneumoniae DNA in peripheral blood mononuclear cells does not seem to be a suitable marker for acute respiratory Chlamydia pneumoniae infection.

Acute Disease↗
PubMed2005

Chlamydia pneumoniae seropositivity and risk of ischemic stroke: a nested case-control study.

Chlamydia pneumoniae has been linked with increased risk of cardiovascular disease, but data on stroke are sparse. We examined whether seropositivity to Chlamydia pneumoniae was associated with the risk of ischemic stroke in a nested case-control study. Data on Chlamydia pneumoniae serology, lifestyle factors, and medical history were obtained at baseline. Verified cases (n = 254) were compared with gender- and age-matched controls (n = 254). Positive IgA (> or = 1:16) or IgG (> or = 1:64) titers were associated with an increased risk of acute ischemic stroke, i.e. adjusted odds ratios (ORs) were 1.54 (95% confidence interval, CI: 0.96-2.47) and 1.28 (95% CI: 0.83-1.95). The adjusted OR was 1.77 (95% CI: 1.04-3.00) when both titers were elevated. The highest point estimates were seen for ischemic stroke due to large-artery atherosclerosis, adjusted OR: 6.32 (95% CI: 0.76-52.61) (IgG (> or = 1:64)). No clear associations were found for other types of ischemic stroke. The strength of the association varied depending on gender and the chosen cut-off values for the antibody titers. These results partly support the hypothesis that serologic evidence of Chlamydia pneumoniae infection may be associated with an increased risk of ischemic stroke. However, the risk may differ according to gender, subtype of ischemic stroke, and cut-off value of antibody titers.

Aged↗
PubMed2003

Chlamydia pneumoniae infection and restenosis in patients with coronary heart disease.

BACKGROUND: The aim of this study was to establish whether Chlamydia pneumoniae is implicated in the development of restenosis in patients with coronary heart disease (CHD) after percutaneous transluminal coronary angioplasty (PTCA). PATIENTS AND METHODS: 67 patients were selected for study after they underwent control angiography after PTCA. Sera were tested for anti-chlamydial antibodies with a genus specific ELISA and a species-specific microimmunofluorescence test (MIFT). Oropharyngeal specimens were examined for the presence of antigen with a Chlamydia immunofluorescence test (IFT), C. pneumoniae IFT and semi-nested PCR. In addition, anamnestic findings were also included. To determine the general level of antibodies, an age- and sex matched control group of 180 persons was also examined for Chlamydia and C. pneumoniae serology. RESULTS: Coronary angiography revealed that 31 of the 67 patients had developed a restenosis. There was no significant correlation between serological and angiographic findings. However, the MIFT showed a higher positive rate, especially in IgA, in the restenosis group. C. pneumoniae was detected in the oropharynx by PCR and/or IFT in 20.8% and 16.0% of the cases in patients with and without a restenosis. PCR found more C. pneumoniae-positive cases in the restenosis patients than IFT. No association was found between the detection of Chlamydia antigen and serology. The women with restenosis were more frequently smokers (p = 0.012). Men with restenosis were significantly older (p = 0.015). C. pneumoniae serology based on the rELISA or the MIFT did not show any correlation with restenosis. CONCLUSION: No evidence was found to suggest that positive C. pneumoniae serology is a risk factor for the development of restenosis. However, whether the species-specific serological test, especially for IgA-antibodies, and the detection of C. pneumoniae in oropharyngeal specimens by PCR might be reliable diagnostic markers in these cases remains to be determined.

Age Distribution↗
PubMed1990

Immunity to Chlamydia psittaci with particular reference to sheep.

Chlamydia psittaci, a zoonotic bacterium, is the causal agent of enzootic abortion of ewes, an important disease of sheep in many European countries. The major thrust of current chlamydial research is directed towards the human pathogen Chlamydia trachomatis. This review attempts to bring together relevant information concerning the host immune response to all members of the genus Chlamydiae and show how this has led to an increased understanding of the ovine humoral and cell mediated immune responses to C. psittaci while emphasising areas where there is still a lack of knowledge. Specifically the review looks at the common immuno-accessible antigens of the Chlamydiae and the antibody responses produced during infection, as well as covering the role of T cells and cytokines in the protective immune response.

Abortion, Veterinary↗
PubMed1991

Abortion in Japanese cows caused by Chlamydia psittaci.

An outbreak of abortion in cows occurring in Niigata Prefecture was shown to be caused by Chlamydia psittaci. Elementary bodies characteristic of Chlamydia were found in the liver of aborted fetuses and C. psittaci antigen was demonstrated by indirect immunofluorescence. Chlamydia was isolated from the liver of aborted fetuses by the yolk sac inoculation of developing chick embryos and by the intraperitoneal inoculation of guinea pigs. Abortion occurred mostly in middle or late pregnancy. Aborted fetuses showed subcutaneous edema and gelatinous infiltration, enlarged liver and spleen, and dark red pleural and ascitic fluid. Focal necrosis was shown in the liver, spleen and lymph nodes. Serological findings and isolation of Chlamydia from fecal specimens indicated a wide dissemination of C. psittaci among cows in the area.

Abortion, Veterinary↗
PubMed1994

Comparison of polymerase chain reaction, direct immunofluorescence, cell culture and enzyme immunoassay for the detection of Chlamydia psittaci in bull semen.

The polymerase chain reaction (PCR), direct immunofluorescence (DIF; JMAGEN Chlamydia, DAKO Diagnostics, UK), cell culture (CC) and enzyme immunoassay (EIA; Syva Micro Trak) were evaluated for detection of Chlamydia psittaci in bull semen. Three specimens were collected from each of 47 bulls at 3-6 month intervals (134 samples). Judging by the number of samples tested (n = 134), PCR showed a sensitivity of 90.9%, DIF of 93.9%, CC of 72.7% and EIA of 81.8%. PCR, DIF, CC and EIA were 100% specific, respectively. Of the 47 bulls the maximum number of chlamydia-positive animals (n = 14) was revealed when repeated tests were made by PCR. PCR detected 21.4% more positives than DIF and CC and 35.7% more than EIA. Although CC was less sensitive judging by the number of samples tested, it was as sensitive as DIF (78.6%) when judged by the number of bulls investigated. All bulls found to be chlamydia-positive remained so throughout the investigation, which lasted 18 months.

Animals↗
PubMed2005

Chlamydia pneumoniae in an ex vivo human artery culture model.

The role of the obligate intracellular pathogen Chlamydia pneumoniae in the development of atherosclerosis could not be completely clarified. Reasons are the highly discrepant results obtained in the hitherto existing studies and the lack of an experimental system allowing the direct examination of chlamydial effects in the human vasculature. We established a human ex vivo organ culture model for the characterization of vascular chlamydial infection. Ninety sections of renal arteries, obtained from nephrectomies, were inoculated with Chlamydia pneumoniae. Using a monoclonal FITC-conjugated antibody, chlamydial LPS was broadly detected in inoculated arteries during the entire observation period of 35 days. However, recultivation of viable organisms from the artery vessel wall was impossible, indicating that productive infection in human arteries did not occur even under optimized conditions. This was substantiated by low recovery rates of Chlamydia pneumoniae, low amounts of detectable chlamydial 16S rRNA and ultramorphological presence of polymorph multilamellar bodies in experimentally infected smooth muscle cells originating from aortas, coronary and renal arteries. We could demonstrate that the complex environment of a human artery did not support the growth of Chlamydia pneumoniae although the presence of chlamydial LPS in the artery vessel wall following experimental infection was a common event. The presence of chlamydial LPS in the absence of viable organisms within the artery vessel wall may explain the failure of antibiotic treatment strategies for atherosclerosis.

Aged↗
PubMedDate not supplied

Clinical and immunological responses of ewes following vaccination with an experimental formalin-inactivated Chlamydia psittaci (ovis) vaccine and subsequent challenge with the live organism during pregnancy.

The protection afforded by an experimental, killed, adjuvanted vaccine derived from the A22 strain of Chlamydia psittaci (ovis) against ovine enzootic abortion was studied. The vaccine was used undiluted (group A), at a dilution of 10(-3) (group B) and at a dilution of 10(-6) (group C). A fourth control group (group D) was inoculated with all components of the vaccine except the chlamydial antigen. A group of rams (group R) was also vaccinated with the chlamydial antigen diluted to 10(-3). Animals were challenged 70 days after mating with the A22 strain of C. psittaci (ovis) and were studied throughout pregnancy and the subsequent lambing period. Their cell-mediated immune responses were examined using a skin test and their humoral immune responses were studied using an ELISA. Tests for excretion of chlamydiae in their faeces and genital tract during pregnancy and after parturition and in the faeces of their lambs were made. The reproductive performance of the ewes was assessed by calculating the average weight of lambs produced per ewe in each group. The experimental vaccine protected the ewes in groups A and B against challenge with C. psittaci (ovis) as none showed clinical signs of OEA or excreted chlamydiae. The average weight of lambs produced per ewe in both groups was greater than 4 kg. Both groups seroconverted after vaccination but not all of them were positive to the skin test. The experimental vaccine at 10(-6) dilution of antigen did not protect the ewes as three of 10 ewes displayed clinical OEA and excreted chlamydiae in the products of parturition.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Veterinary↗
PubMed1995

Respiratory chlamydia: the management of an outbreak.

This investigation was undertaken in response to the occurrence of nine cases of respiratory chlamydial infection in 8 months within the district of Dudley. All nine cases of respiratory chlamydia were due to Chlamydia psittaci, not Chlamydia pneumoniae. Five cases had avian exposure, but no other aetiological factors were identified. Faecal specimens were obtained from only two of the implicated birds and were negative. Two local aviaries were identified as sources of implicated birds. The two aviaries were themselves linked. Bird faecal specimens were taken from the two implicated aviaries and were both positive for Chlamydia psittaci. Appropriate public health control measures were introduced in these aviaries. A press statement was released to identify and advise, by telephone, those who purchased birds from the aviaries.

Adult↗
PubMed2004

Chlamydia pneumoniae infection related atherosclerotic clinical variables on carotid stenosis.

OBJECTIVE: Research results showed that Chlamydia pneumoniae infection is related to atherosclerosis. C. pneumoniae infection may exacerbate atherogenesis. We investigated the presence of this microorganism for patients who underwent carotid endarterectomy and evaluated clinical values of C. pneumoniae infection on carotid stenosis. METHODS: Twenty patients with carotid stenosis were enrolled in this prospective study between 1997 and 1999. The patients were observed on whether they were positive or negative in four C. pneumoniae measures, namely; IgA titers, IgG titers, presence of electron microscopy, and immunocytochemistry in the endarterectomy specimens. Possible clinical findings for atherosclerosis were also observed of Chlamydial measures such as the percentage of carotid stenosis, cholesterol and triglyceride levels, smoking status, symptomatic or non-transient ischaemic attack or stroke, previous ischaemic event, calcification at surgery, ulceration on angiographies, ulceration at surgery and hypertension were included in this evaluation. RESULTS: Specific C. pneumoniae IgG were detected as positive in 9 (45%) of 20 patient samples. These patients were regarded as having chronic Chlamydia pneumoniae infection. None of the patients were positive for IgA antibody. This result demonstrated no evidence of reinfection. Immunocytochemistry and electron microscopy were positive in 7 (35%) of the 20 patients and correlated with positive serological results. The proportion of previous ischaemic events, calcification at surgery, ulceration on angiography, and ulceration at surgery were found significantly higher ( p < 0.05 ) for patients who are positive for chlamydial measures than those who are negative. CONCLUSION: The results of this study demonstrated an association between C. pneumoniae to atherosclerosis. The proportion of patients who are positive for Chlamydia measures (IgG titers, electron microscopy, and immunocytochemistry) is significantly higher for those who were positive for each of these clinical variables (PIE, CALCI, U1, and U2) than who were negative. We emphasise, the higher incidence in clinical variables of PIE, CALCI, U1, and U2 in Chlamydia measures positive group may support the association of C. pneumoniae with atherosclerotic events.

Adult↗
PubMed1994

Association of Chlamydia IgG Titers with Laproscopic Findings of Dystrophic Calcification and Hydrosalpinges but not with Endosalpingiosis

Psammoma bodies are discrete forms of dystrophic calcification which represent cross-sections of calcified papillary formations. At laparoscopy, these have been confused with both endometriosis and cancer. A recent abstract (Khare et al: AAGL, 1993) reported the association of peritoneal psammoma bodies (grain-like inclusions) with positive IgG chlamydia titers (p=0.012). The purpose of this study is to investigate a possible correlation of chlamydia IgG titers with endosalpinges. Histologic slides and charts of 60 consecutive women were reviewed in a blinded fashion for calcification, hydrosalpinx, endosalpingiosis, and other significant changes. Although dystrophic calcification and hydrosalpinges were associated with positive chlamydia IgG titers (p<0.05), endosalpingiosis was found in only one patient. This study confirms previous studies in showing a relationship of chlamydia IgG titers with dystrophic calcification and hydrosalpinges but did not demonstrate a relationship with endosalpingiosis.

Journal Article↗
PubMed2000

Phage infection of the obligate intracellular bacterium, Chlamydia psittaci strain guinea pig inclusion conjunctivitis.

The infectious cycle of phiCPG1, a bacteriophage that infects the obligate intracellular pathogen, Chlamydia psittaci strain Guinea Pig Inclusion Conjunctivitis, was observed using transmission electron microscopy of phage-hyperinfected, Chlamydia-infected HeLa cells. Phage attachment to extracellular, metabolically dormant, infectious elementary bodies and cointernalisation are demonstrated. Following entry, phage infection takes place as soon as elementary bodies differentiate into metabolically active reticulate bodies. Phage-infected bacteria follow an altered developmental path whereby cell division is inhibited, producing abnormally large reticulate bodies, termed maxi-reticulate bodies, which do not mature to elementary bodies. These forms eventually lyse late in the chlamydial developmental cycle, releasing abundant phage progeny in the inclusion and, upon lysis of the inclusion membrane, into the cytosol of the host cell. Structural integrity of the hyperinfected HeLa cell is markedly compromised at late stages. Released phage particles attach avidly to the outer leaflet of the outer membranes of lysed and unlysed Chlamydiae at different stages of development, suggesting the presence of specific phage receptors in the outer membrane uniformly during the chlamydial developmental cycle. A mechanism for phage infection is proposed, whereby phage gains access to replicating chlamydiae by attaching to the infectious elementary body, subsequently subverting the chlamydial developmental cycle to its own replicative needs. The implications of phage infection in the context of chlamydial infection and disease are discussed.

Animals↗
PubMed1994

The role of Chlamydia pneumoniae in severe acute tonsillitis.

Chlamydia pneumoniae has been implicated as a cause of tonsillitis and pharyngitis, but the incidence has varied from one to 19 per cent in various studies. We investigated 51 patients admitted to University College Hospital, Galway, with severe tonsillitis. Throat swabs were examined for evidence of Chlamydia pneumoniae using a direct monoclonal antibody test. Blood was taken for serology from 45 patients. A further specimen was taken at six weeks. A control group of 32 blood bank sera was used. Mean hospital stay was three days (one to eight). Five patients (10 per cent) were monospot positive. Chlamydia pneumoniae was identified by direct immunofluorescence on a tonsillar swab from one patient who did not seroconvert. IgG antibody was identified in 13 cases (29 per cent) and in seven of the control group (22 per cent). No serological evidence of recent infection was found. Chlamydia pneumoniae was not found to be a cause of severe acute tonsillitis in our study group.

Acute Disease↗
PubMed2000

Experimental enteric infection of gnotobiotic piglets with a Chlamydia psittaci strain of avian origin.

The pathogenicity of a Chlamydia psittaci isolate of pigeon origin was assessed using a litter of gnotobiotic piglets. At 3 days of age, six piglets were inoculated intragastrically with egg-grown chlamydiae, the remaining six pigs were sham-inoculated. The animals were observed for clinical signs, and they were killed and necropsied sequentially between 4 and 15 days of age. Clinical manifestations consisted of slight softening of the faeces between 6 and 10 days post-inoculation (DPI). Immunohistochemistry revealed chlamydial replication predominantly in the small intestine, initially within villous enterocytes, after 4 DPI mostly in the lamina propria. Histopathology showed villous atrophy and increased numbers of inflammatory cells in the gut up to 6 DPI. Chlamydial stages of normal morphology were identified within enterocytes using transmission electron microscopy. An enzyme-linked immunosorbent assay (ELISA) run on faecal samples revealed shedding of chlamydial antigen from 3 until 11 DPI. Systemic dissemination of Chlamydia occurred to a limited extent according to polymerase chain reaction and immunohistochemistry results of several extraintestinal organs. Corresponding histopathological changes were minimal. Sera of all pigs were negative for anti-chlamydial antibodies using a complement fixation test. In conclusion, inoculation of this isolate in gnotobiotic piglets resulted in a productive enteric infection with mild lesions, weak systemic dissemination, and faecal shedding, indicating the pig as a potential host for avian chlamydiae.

Animals↗
PubMed2002

Does infection with Chlamydia pneumoniae and/or Helicobacter pylori increase the expression of endothelial cell adhesion molecules in humans?

OBJECTIVE: To investigate if Chlamydia pneumoniae and/or Helicobacter pylori seropositivity is associated with elevated levels of soluble endothelial cell adhesion molecules (sCAMs) as markers of atherosclerotic activity. METHODS: Immunoglobulin A (IgA) and IgG antibodies to the two bacteria, soluble intercellular cell adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1) and E-selectin were measured in coronary heart disease (CHD) patients (n = 193) and age- and sex-matched controls (n = 193). Two different serological methods were used for the detection of Chlamydia antibodies: Labsystems microimmunofluorescence to detect species-specific C. pneumoniae antibodies and Medac's recombinant enzyme-linked immunosorbent assay to detect genus-specific lipopolysaccharide antibodies. RESULTS: The concentrations of sICAM-1 and E-selectin were higher in CHD patients with positive vs. negative Chlamydia lipopolysaccharide IgA (P = 0.044 for both). H. pylori antibodies alone did not predict raised levels of sCAMs, but in CHD patients sICAM-1 was increased with IgA seropositivity to both bacteria compared to double seronegativity (P = 0.034). Concentrations of sVCAM-1 were elevated in CHD patients with double IgA seropositivity compared to those with Chlamydia lipopolysaccharide IgA seropositivity alone (P = 0.018). CONCLUSION: Our results may indicate that C. pneumoniae contributes to increased inflammation in CHD, and that this contribution is even more pronounced when present in combination with H. pylori IgA antibodies.

Adult↗
PubMed1998

Enhancement of ATP levels and glucose metabolism during an infection by Chlamydia. NMR studies of living cells.

The Chlamydia species are obligate intracellular bacteria that proliferate only within the infected cell. Since the extracellular bacteria are metabolically inert and there are no cell-free systems for characterizing Chlamydia metabolism, we studied metabolic changes related to ATP synthesis and glycolysis in HeLa cells infected with Chlamydia psittaci during the course of the 2-day infection cycle using noninvasive 31P and 13C NMR methods. We find that the infection stimulates ATP synthesis in the infected cell, with a peak of ATP levels occurring midway through the infection cycle, when most of the metabolically active bacteria are proliferating. The infection also stimulates synthesis of glutamate with a similar time course as for ATP. The stimulation is apparently due to an enhancement in glucose consumption by the infected cell, which also results in an increased rate of lactate production and glutamate synthesis as well as higher glycogen accumulation during the infection. Concurrently, infection leads to an increase in the expression of the glucose transporter, GLUT-1, on HeLa cells, which may account for the enhanced glucose consumption. The chlamydiae are thus able to stimulate glucose transport in the host cell sufficiently to compensate for the extra energy load on the cell represented by the infection.

Adenosine Triphosphate↗
PubMed1996

A reverse transcriptase-PCR based assay for in-vitro antibiotic susceptibility testing of Chlamydia pneumoniae.

Infections caused by Chlamydia spp are an important cause of human disease, and the accuracy and reproducibility of antimicrobial susceptibility tests for these bacteria could have considerable clinical implications. We have developed a reverse transcriptase PCR (RT-PCR) based method to determine the antibiotic susceptibility of Chlamydia spp., and compared this with conventional tests using immunofluoresence (IF) staining. The MICs of antimicrobial agents for a test strain of Chlamydia pneumoniae were higher by RT-PCR as compared with IF staining, indicating the greater stringency of the former method. Using RT-PCR, doxycycline and tetracycline were the most active agents (MIC 1 mg/L), followed by erythromycin (1.6 mg/L), and ciprofloxacin (16 mg/L). Neither trimethoprim nor sulphamethoxazole (400 mg/L) inhibited growth as assessed by both techniques. The RT-PCR based method may thus represent an improved and less time consuming assay for in-vitro determination of the antibiotic susceptibility of Chlamydia spp.

Anti-Bacterial Agents↗
PubMed2003

Genome sequence of Chlamydophila caviae (Chlamydia psittaci GPIC): examining the role of niche-specific genes in the evolution of the Chlamydiaceae.

The genome of Chlamydophila caviae (formerly Chlamydia psittaci, GPIC isolate) (1 173 390 nt with a plasmid of 7966 nt) was determined, representing the fourth species with a complete genome sequence from the Chlamydiaceae family of obligate intracellular bacterial pathogens. Of 1009 annotated genes, 798 were conserved in all three other completed Chlamydiaceae genomes. The C.caviae genome contains 68 genes that lack orthologs in any other completed chlamydial genomes, including tryptophan and thiamine biosynthesis determinants and a ribose-phosphate pyrophosphokinase, the product of the prsA gene. Notable amongst these was a novel member of the virulence-associated invasin/intimin family (IIF) of Gram-negative bacteria. Intriguingly, two authentic frameshift mutations in the ORF indicate that this gene is not functional. Many of the unique genes are found in the replication termination region (RTR or plasticity zone), an area of frequent symmetrical inversion events around the replication terminus shown to be a hotspot for genome variation in previous genome sequencing studies. In C.caviae, the RTR includes several loci of particular interest including a large toxin gene and evidence of ancestral insertion(s) of a bacteriophage. This toxin gene, not present in Chlamydia pneumoniae, is a member of the YopT effector family of type III-secreted cysteine proteases. One gene cluster (guaBA-add) in the RTR is much more similar to orthologs in Chlamydia muridarum than those in the phylogenetically closest species C.pneumoniae, suggesting the possibility of horizontal transfer of genes between the rodent-associated Chlamydiae. With most genes observed in the other chlamydial genomes represented, C.caviae provides a good model for the Chlamydiaceae and a point of comparison against the human atherosclerosis-associated C.pneumoniae. This crucial addition to the set of completed Chlamydiaceae genome sequences is enabling dissection of the roles played by niche-specific genes in these important bacterial pathogens.

Adhesins, Bacterial↗