The 1B vaccine strain of Chlamydia abortus produces placental pathology indistinguishable from a wild type infection

Chlamydia abortus is one of the most commonly diagnosed causes of infectious abortion in small ruminants worldwide. Control of the disease (Enzootic Abortion of Ewes or EAE) is achieved using the commercial live, attenuated C. abortus 1B vaccine strain, which can be distinguished from virulent wild-type (wt) strains by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Published studies applying this typing method and whole-genome sequence analyses to cases of EAE in vaccinated and non-vaccinated animals have provided strong evidence that the 1B strain is not attenuated and can infect the placenta causing disease in some ewes. Therefore, the objective of this study was to characterise the lesions found in the placentas of ewes vaccinated with the 1B strain and to compare these to those resulting from a wt infection. A C. abortus-free flock of multiparous adult ewes was vaccinated twice, over three breeding seasons, each before mating, with the commercial C. abortus 1B vaccine strain (Cevac® Chlamydia, Ceva Animal Health Ltd.). In the second lambing season following vaccination, placentas (n = 117) were collected at parturition and analysed by C. abortus-specific real-time quantitative PCR (qPCR). Two placentas, from a single ewe, which gave birth to live twin lambs, were found to be positive by qPCR and viable organisms were recovered and identified as vaccine type (vt) by PCR-RFLP, with no evidence of any wt strain being present. All cotyledons from the vt-infected placentas were analysed by histopathology and immunohistochemistry and compared to those from wt-infected placentas. Both vt-infected placentas showed lesions typical of those found in a wt infection in terms of their severity, distribution, and associated intensity of antigen labelling. These results conclusively demonstrate that the 1B strain can infect the placenta, producing typical EAE placental lesions that are indistinguishable from those found in wt infected animals.

Assessment of evidence for or against contributions of Chlamydia pneumoniae infections to Alzheimer's disease etiology

Alzheimer's disease, the most common form of dementia, was first formally described in 1907 yet its etiology has remained elusive. Recent proposals that Aβ peptide may be part of the brain immune response have revived longstanding contention about the possibility of causal relationships between brain pathogens and Alzheimer's disease. Research has focused on infectious pathogens that may colonize the brain such as herpes simplex type I. Some researchers have proposed the respiratory bacteria Chlamydia pneumoniae may also be implicated in Alzheimer's disease, however this remains controversial. This review aims to provide a balanced overview of the current evidence and its limitations and future approaches that may resolve controversies. We discuss the evidence from in vitro, animal and human studies proposed to implicate Chlamydia pneumoniae in Alzheimer's disease and other neurological conditions, the potential mechanisms by which the bacterium may contribute to pathogenesis and limitations of previous studies that may explain the inconsistencies in the literature.

Relationship between peripheral arterial occlusive disease (PAOD) and chronic Chlamydophila (Chlamydia) pneumoniae infection

We carried out a meta-analysis of observational case-control studies published before May 2004 to assess the degree of association between Chlamydophila pneumoniae (Cp) infection and PAOD. A search of the Medline database was performed using atherosclerosis and "Chlamyd* pneumoniae" as keywords. Strict criteria were applied for the selection of case studies, which had to be studies of Cp seroprevalence or of Cp detection in patients versus controls. Forty-three published studies that met these criteria were selected. An association between PAOD and Cp was revealed by immunohistochemical analysis (OR=15.4, 95%CI=5.0–46.9) and nested PCR studies of arterial biopsies (OR=4.3, 95%CI=1.8–10), by PCR study of non-arterial samples (OR=2.9, 95%CI=1.2–7.0), by other direct-detection tests (OR=16.7, 95%CI=7.0–39.8), and by ELISA and MIF tests to detect high IgG (OR=2, 95%CI=1.1–3.5 and OR=1.7, 95%CI=1.0–2.9, respectively) and IgA (OR=1.9, 95%CI=1.1–3.4 and OR=1.5, 95%CI=1.1–2.0, respectively) titers. No significant association was found in simple PCR studies of arterial biopsies, MIF tests to detect low IgG titers or IgM, or ELISA studies to detect IgM. According to this review, the association between Cp infection and PAOD depends on the analytical method adopted. Establishing a relationship between Cp and PAOD will require a case-control study with an adequate number of cases and samples that uses a combination of direct and indirect techniques to identify the presence of the bacterium in different types of sample from the same subjects, correlating the results with the activity of the disease.

The impact of pathogen burden on leukocyte telomere length in the Multi-Ethnic Study of Atherosclerosis

Several infections have been linked to telomere shortening and in some cases these associations have varied by sex. We assessed the association between seropositivity to four persistent pathogens (cytomegalovirus (CMV), herpes simplex virus-1, Helicobacter pylori, Chlamydia pneumoniae), and total pathogen burden on leukocyte telomere length in a diverse US sample. Data came from the Multi-Ethnic Study of Atherosclerosis, a population-based cohort study. We utilized cross-sectional survey data, and biological samples from participants tested for pathogens and telomere length (N = 163). Linear regression was used to examine the association between seropositivity for individual pathogens as well as total pathogen burden and telomere length, adjusting for various confounders. CMV seropositivity and increased total pathogen burden level were significantly associated with shorter telomere length among females (β = -0·1204 (standard error (s.e.) 0·06), P = 0·044) and (β = -0·1057 (s.e. = 0·05), P = 0·033), respectively. There was no statistically significant association among males. Our findings suggest that prevention or treatment of persistent pathogens, in particular CMV, may play an important role in reducing telomere shortening over the life course among women. Future research is needed to confirm these novel findings in larger longitudinal samples.

Prospective etiological investigation of community-acquired pulmonary infections in hospitalized people living with HIV

The study of the etiological agents of community-acquired pulmonary infections is important to guide empirical therapy, requires constant updating, and has a substantial impact on the prognosis of patients. The objective of this study is to determine prospectively the etiology of community-acquired pulmonary infections in hospitalized adults living with HIV. Patients were submitted to an extended microbiological investigation that included molecular methods. The microbiological findings were evaluated according to severity of the disease and pneumococcal vaccine status. Two hundred twenty-four patients underwent the extended microbiological investigation of whom 143 (64%) had an etiology determined. Among the 143 patients with a determined etiology, Pneumocystis jirovecii was the main agent, detected in 52 (36%) cases and followed by Mycobacterium tuberculosis accounting for 28 (20%) cases. Streptococcus pneumoniae and Rhinovirus were diagnosed in 22 (15%) cases each and influenza in 15 (10%) cases. Among atypical bacteria, Mycoplasma pneumoniae was responsible for 12 (8%) and Chlamydophila pneumoniae for 7 (5%) cases. Mixed infections occurred in 48 cases (34%). S pneumoniae was associated with higher severity scores and not associated with vaccine status. By using extended diagnostics, a microbiological agent could be determined in the majority of patients living with HIV affected by community-acquired pulmonary infections. Our findings can guide clinicians in the choice of empirical therapy for hospitalized pulmonary disease.

Evaluation of Chlamydophila Abortus DNA Extraction Protocols for Polymerase Chain Reaction Diagnosis in Paraffin-Embedded Tissues

Polymerase chain reaction (PCR) has gained increasing importance as a tool for directly demonstrating the presence of Chlamydophila in the placentas of aborted sheep and goats. However, because of the zoonotic potential of the disease, it is advisable to use fixed materials. To evaluate 4 different DNA extraction protocols in paraffin-embedded sections for PCR, previously immunohistochemically diagnosed placental samples from outbreaks of abortions in goats and sheep were used. The samples were also used to evaluate the effect of the duration of fixation in formalin on PCR. A protocol that uses Tris-HCl pH 8.5 with EDTA and subsequent digestion with proteinase K was found to be an easy protocol for obtaining excellent PCR products for Chlamydophila abortus diagnosis from formalin-fixed and paraffin-embedded specimens. It was also found that if samples are fixed in formalin for more than 2 weeks, the PCR technique is affected more adversely than immunohistochemical methods.

Kinetics of Infection and Effects on the Placenta of Clamydophila abortus in Experimentally Infected Pregnant Ewes

A Chlamydophila abortus-induced abortion model was carried out on the basis of the experimental infection of ewes at day 75 of gestation. The infection induced abortions and the birth of weak lambs during the last 3 weeks of pregnancy. To study the kinetics of the infection in the placenta and in other organs, infected ewes were killed at 105, 120, and 130 days of gestation and also several days after abortion or parturition. Infected ewes developed a systemic infection that caused a mild and transient pneumonia and focal hepatitis. Pathologic changes were observed in placentas at 120 day of gestation, although the lesions varied between animals and even between placentomes of the same placenta. The first placental area infected was the maternal stroma and epithelium next to the intercaruncular areas, where neutrophilic response seemed to control the infection. A substantial degree of multiplication of C. abortus was then observed in the trophoblast cells of the placentome, periplacentomal choriallantoic membranes, and hilius, with an inflammatory exudate composed mainly of neutrophils, some macrophages, and very scarce lymphocytes. After abortion, the lesions affected the intercotyledonary areas of the aborted placentas, whereas in the uterus significant lymphocyte infiltration was observed, together with a rapid decrease of the C. abortus antigen in the degenerated caruncular tissues.

Serotyping of US Isolates of Chlamydophila Psittaci from Domestic and Wild Birds

The identities of chlamydial strains, which can infect a given host, are important to know for disease prognosis, disease control, and epidemiology. The microimmunofluorescence test (MIFT) was used with a panel of 14 serovar-specific monoclonal antibodies (MAbs) to serotype 150 chlamydial isolates from domestic and wild birds. The isolates were obtained from birds submitted to diagnostic laboratories or during investigation of outbreaks. The 150 US isolates included 96 from the order Psittaciformes, 14 isolates from the order Columbiformes, 2 from the order Passeriformes, 16 from the order Galliformes, 12 from the order Struthioniformes, and 3 from the order Falconiformes. A total of 93, or 97%, of the Psittaciformes isolates were of serovar A; 11, or 79%, of the Columbiformes isolates were of serovar B; 64% of the Galliformes isolates were of serovar D, and all the Struthioniformes isolates were of serovar E. The 3 Falconiformes isolates did not react with any of the MAbs to the avian and mammalian isolates and are presumed to represent a new strain. The results show that specific chlamydial strains are usually associated with certain types of birds and that some serovars may be unusually virulent for certain species of birds. The MIFT using serovar-specific MAbs provides a rapid method to serotype new isolates, making it a useful system for epidemiological studies.

Identification of Chlamydophila Pneumoniae in an Emerald Tree Boa, Corallus Caninus

Tissues were evaluated from emerald tree boas, Corallus caninus, from a collection in which chlamydiosis was diagnosed. To determine the strain of chlamydia infecting these snakes, tissue samples from 5 frozen snakes were tested by a quantitative TaqMan polymerase chain reaction (PCR) test and a PCR sequence analysis test. Of the 22 samples tested, 9 were categorized as either positive or weakly positive with the TaqMan test, and 6 yielded an amplicon using a serial PCR test that amplified a portion of the 23S ribosomal RNA gene. A PCR product suitable for sequencing was obtained from the heart of one of the snakes. Sequence analysis showed that the snake had been infected with Chlamydophila pneumoniae. These findings show that C. pneumoniae can infect emerald tree boas, broadening the range of reptiles known to be infected by this primarily human pathogen.

The Type III Secretion System-Related CPn0809 from Chlamydia pneumoniae

Chlamydia pneumoniae is an intracellular Gram-negative bacterium that possesses a type III secretion system (T3SS), which enables the pathogen to deliver, in a single step, effector proteins for modulation of host-cell functions into the human host cell cytosol to establish a unique intracellular niche for replication. The translocon proteins located at the top of the T3SS needle filament are essential for its function, as they form pores in the host-cell membrane. Interestingly, unlike other Gram-negative bacteria, C. pneumoniae has two putative translocon operons, named LcrH_1 and LcrH_2. However, little is known about chlamydial translocon proteins. In this study, we analyzed CPn0809, one of the putative hydrophobic translocators encoded by the LcrH_1 operon, and identified an 'SseC-like family' domain characteristic of T3S translocators. Using bright-field and confocal microscopy, we found that CPn0809 is associated with EBs during early and very late phases of a C. pneumoniae infection. Furthermore, CPn0809 forms oligomers, and interacts with the T3SS chaperone LcrH_1, via its N-terminal segment. Moreover, expression of full-length CPn0809 in the heterologous host Escherichia coli causes a grave cytotoxic effect that leads to cell death. Taken together, our data indicate that CPn0809 likely represents one of the translocon proteins of the C. pneumoniae T3SS, and possibly plays a role in the translocation of effector proteins in the early stages of infection.

Systems Biology Approaches for the Prediction of Possible Role of Chlamydia pneumoniae Proteins in the Etiology of Lung Cancer

Accumulating evidence has recently supported the association of bacterial infection with the growth and development of cancers, particularly in organs that are constantly exposed to bacteria such as the lungs, colon, cervical cancer etc. Our in silico study on the proteome of Chlamydia pneumoniae suggests an unprecedented idea of the etiology of lung cancer and have revealed that the infection of C. pneumoniae is associated with lung cancer development and growth. It is reasonable to assume that C. pneumoniae transports its proteins within host-intracellular organelles during infection, where they may work with host-cell proteome. The current study was performed for the prediction of nuclear targeting protein of C. pneumoniae in the host cell using bioinformatics predictors including ExPASy pI/Mw tool, nuclear localization signal (NLS) mapper, balanced sub cellular localization predictor (BaCeILo), and Hum-mPLoc 2.0. We predicted 47/1112 nuclear-targeting proteins of C. pneumoniae connected with several possible alterations in host replication and transcription during intracellular infection. These nuclear-targeting proteins may direct to competitive interactions of host and C. pneumoniae proteins with the availability of same substrate and may be involved as etiological agents in the growth and development of lung cancer. These novel findings are expected to access in better understanding of lung cancer etiology and identifying molecular targets for therapy.

Pneumonia Outbreak Caused by Chlamydophila pneumoniae among US Air Force Academy Cadets, Colorado, USA

During October 2013–May 2014, there were 102 cases of pneumonia diagnosed in US Air Force Academy cadets. A total of 73% of tested nasal washes contained Chlamydophila pneumoniae. This agent can be considered to be present on campus settings during outbreaks with numerous, seemingly disconnected cases of relatively mild pneumonia.

M2 Polarization of Human Macrophages Favors Survival of the Intracellular Pathogen Chlamydia pneumoniae

Intracellular pathogens have developed various strategies to escape immunity to enable their survival in host cells, and many bacterial pathogens preferentially reside inside macrophages, using diverse mechanisms to penetrate their defenses and to exploit their high degree of metabolic diversity and plasticity. Here, we characterized the interactions of the intracellular pathogen Chlamydia pneumoniae with polarized human macrophages. Primary human monocytes were pre-differentiated with granulocyte macrophage colony-stimulating factor or macrophage colony-stimulating factor for 7 days to yield M1-like and M2-like macrophages, which were further treated with interferon-γ and lipopolysaccharide or with interleukin-4 for 48 h to obtain fully polarized M1 and M2 macrophages. M1 and M2 cells exhibited distinct morphology with round or spindle-shaped appearance for M1 and M2, respectively, distinct surface marker profiles, as well as different cytokine and chemokine secretion. Macrophage polarization did not influence uptake of C. pneumoniae, since comparable copy numbers of chlamydial DNA were detected in M1 and M2 at 6 h post infection, but an increase in chlamydial DNA over time indicating proliferation was only observed in M2. Accordingly, 72±5% of M2 vs. 48±7% of M1 stained positive for chlamydial lipopolysaccharide, with large perinuclear inclusions in M2 and less clearly bordered inclusions for M1. Viable C. pneumoniae was present in lysates from M2, but not from M1 macrophages. The ability of M1 to restrict chlamydial replication was not observed in M1-like macrophages, since chlamydial load showed an equal increase over time for M1-like and M2-like macrophages. Our findings support the importance of macrophage polarization for the control of intracellular infection, and show that M2 are the preferred survival niche for C. pneumoniae. M1 did not allow for chlamydial proliferation, but failed to completely eliminate chlamydial infection, giving further evidence for the ability of C. pneumoniae to evade cellular defense and to persist in human macrophages.

Genomic factors related to tissue tropism in Chlamydia pneumoniae infection

BACKGROUND

Chlamydia pneumoniae (Cpn) are obligate intracellular bacteria that cause acute infections of the upper and lower respiratory tract and have been implicated in chronic inflammatory diseases. Although of significant clinical relevance, complete genome sequences of only four clinical Cpn strains have been obtained. All of them were isolated from the respiratory tract and shared more than 99% sequence identity. Here we investigate genetic differences on the whole-genome level that are related to Cpn tissue tropism and pathogenicity.

RESULTS

We have sequenced the genomes of 18 clinical isolates from different anatomical sites (e.g. lung, blood, coronary arteries) of diseased patients, and one animal isolate. In total 1,363 SNP loci and 184 InDels have been identified in the genomes of all clinical Cpn isolates. These are distributed throughout the whole chlamydial genome and enriched in highly variable regions. The genomes show clear evidence of recombination in at least one potential region but no phage insertions. The tyrP gene was always encoded as single copy in all vascular isolates. Phylogenetic reconstruction revealed distinct evolutionary lineages containing primarily non-respiratory Cpn isolates. In one of these, clinical isolates from coronary arteries and blood monocytes were closely grouped together. They could be distinguished from all other isolates by characteristic nsSNPs in genes involved in RB to EB transition, inclusion membrane formation, bacterial stress response and metabolism.

CONCLUSIONS

This study substantially expands the genomic data of Cpn and elucidates its evolutionary history. The translation of the observed Cpn genetic differences into biological functions and the prediction of novel pathogen-oriented diagnostic strategies have to be further explored.

Molecular evidence for genetic distinctions between Chlamydiaceae detected in Siamese crocodiles (Crocodylus siamensis) and known Chlamydiaceae species

Chlamydiosis, caused by Chlamydiaceae, is a zoonotic disease found in humans and several species of animals, including reptiles and amphibians. Although chlamydiosis in saltwater crocodiles has been previously reported in South Africa and Papua New Guinea, the reported strains have not been identified or confirmed. Therefore, the main aim of this study was to sequence and characterize Chamydiaceae isolated from Siamese crocodiles. Results showed the 16S ribosomal (r) RNA and the 16S/23S rRNA gene of the crocodile isolates were closely related to the genus Chlamydophila with matched identity greater than 98%. The phylogenetic tree constructed from the 16S/23S rRNA gene showed the crocodile cluster diverges far from Cp. caviae with a 100% bootstrap value. The tree based on the ompA gene loci distinguished the crocodile strains into genotypes I, II, and III. The present study is the first report on Chlamydophila detected in Siamese crocodiles that is genetically distinct from the known species of Chlamydiaceae.

Higher titers of anti-Chlamydia pneumoniae IgG in diabetic retinopathy: a cross-sectional study

BACKGROUND

Chronic inflammation has a role in the pathogenesis of diabetic retinopathy. Infection with intracellular organisms may incite chronic inflammation. This study was conducted to investigate the association between previous infection with Chlamydia pneumoniae (an intracellular microorganism) and diabetic retinopathy.

METHODS

Patients with type 2 diabetes mellitus (30-60 years old) and age-matched normal controls were recruited. Patients with history of cardiovascular or cerebrovascular disease, recent pulmonary infection and the presence of age-related macular degeneration were excluded from the study. Complete ophthalmic examinations were performed. Fasting blood sugar and haemoglobin levels were measured in diabetic patients and controls, and HgbA1c , blood urea nitrogen, creatinine and 24-h urine protein were measured in diabetic patients. Anti-C. pneumoniae IgG (enzyme-linked immunosorbent assay) was measured in the sera of all participants.

RESULTS

A total of 215 type 2 diabetic patients and 243 normal healthy controls were included. Anti-C. pneumoniae IgG titers were higher in patients affected by diabetic retinopathy than participants without retinopathy (74.78 ± 33.38 vs 66.18 ± 31.40, p = 0.028). Diabetic patients with diabetic retinopathy also had higher titers than diabetic patients without diabetic retinopathy (74.78 ± 33.38 vs 66.11 ± 33.41, p = 0.042). Of different variables including age, body mass index, haemoglobin level, glycated haemoglobin level, fasting blood sugar, mean arterial pressure and blood urea nitrogen, only age (r = 0.17; p = 0.001) and body mass index (r = 0.15; p = 0.003) were correlated with anti-C. pneumoniae IgG levels. In regression analysis, the presence of diabetic retinopathy was still a determinant of the antibody level (p = 0.03).

CONCLUSION

Anti-C. pneumoniae IgG titers were higher in patients with diabetic retinopathy, which may indicate a role of this infection in the pathogenesis of diabetic retinopathy.

Enzymatic characterization of Chlamydophila pneumoniae phospholipase D

Chlamydophila pneumoniae, an aetiological agent of respiratory infection, is also thought to play an immuno-pathogenetic role in atherosclerosis by contributing to inflammation and plaque instability. Phospholipase D (PLD) is an enzyme involved in lipid metabolism and may have a direct or indirect impact on virulence and the inflammatory response. Some aspects of the developmental cycle of C. pneumoniae suggest a direct implication of its PLD (CpPLD) in the pathogenesis, specifically by affecting the regulation of lipid metabolism and lipid exchange between C. pneumoniae and host cells. Our previous studies disclosed a specific anti-CpPLD antibody response in patients with acute coronary syndromes chronically infected with C. pneumoniae, and demonstrated that this antigen is a factor able to drive the inflammatory process in atherosclerosis. Due to the intriguing aspects of the CpPLD, the present study investigated CpPLD enzymatic activity of the protein and the two domains that include one HKD motif each polypeptide. Our results showed that CpPLD was able to synthesize the cardiolipin (CL) but unable to hydrolyze phospholipids. It was also observed that each single HKD motif has an independent CL synthetase activity. This enzymatic activity of CpPLD could be important in the inflammatory process within the atherothrombotic events.

[Chlamydia pneumoniae persistent infection is associated with primary IgA nephropathy]

OBJECTIVE

To explore the correlations between Chlamydia pneumoniae (CP) infection and IgA nephropathy (IgAN).

METHODS

Seventy patients with primary IgAN were enrolled in the study. Seventy serum specimens from healthy blood donors and twelve renal autopsy specimens from accidental death bodies were regarded as control groups. Serum CP IgG and CP IgA antibody titers were detected by indirect immunofluorescence. CP DNA of renal tissue was measured by fluorescent quantitative PCR. Finally, using statistical methods, we analyzed the correlations of CP infection and CP DNA of renal tissue with clinical manifestations and kidney pathological changes of IgAN patients.

RESULTS

The rate of CP persistent infection in IgAN group was higher than that of healthy blood donor group (P<0.01). The rate was not significantly different within the IgAN group, such as among acute infection, previous infection and no infection subgroups (P>0.05). It was higher in the patients with gross proteinuria and/or durative renal insufficiency than in non-gross proteinuria patients (P<0.05). The scores of glomerular patholopical and tubulointerstitial injury of CP persistent infection patients were higher than those of non-persistent infection ones (P<0.05). The renal injury of CP persistent infection patients was more severe than that of non-persistent infection ones. The positive rate of CP DNA in gross proteinuria and/or renal insufficiency patients was higher than that of non-gross proteinuria patients (P<0.05). The scores of glomerular pathological and tubulointerstitial injury of positive CP DNA patients were respectively higher than those of negative CP DNA ones (P<0.05, P<0.01). The renal injury of patients with positive CP DNA was more severe than that of negative CP DNA ones. CP persistent infection was obviously correlated with renal CP DNA (P<0.01).

CONCLUSION

Primary IgAN is associated with CP persistent infection, but not with CP previous infection or CP acute infection.

Chlamydia pneumoniaeRespiratory Infections in Taiwan

To understand the epidemiology of Chlamydia pneumoniae acute infections in Taiwan, we collected 116 paired and 244 single sera from patients suspected of C. pneumoniae infection and conducted microimmunofluorescence test. Eighty-three patients (83/360, 23%) met the diagnostic criteria of current C. pneumoniae infection. The C. pneumoniae infections were significantly higher in men than in women (P< or =0.0001) and were most frequent in the group of 40-49 year-olds, and the people older than 70 years old. C. pneumoniae infection often occurred in the late autumn lasting to the cold winter and in the transition period between the spring and summer.

Chlamydophila pneumoniae and Mycoplasma pneumoniae were not identified in sinus mucosa of patients with chronic rhinosinusitis

Chronic rhinosinusitis is a symptomatic inflammation of the mucosa of the nose and paranasal sinuses lasting for at least 12 weeks. Atypical bacteria Chlamydophila pneumoniae and Mycoplasma pneumoniae are important causes of human respiratory tract infection. Also, they were identified in bronchial respiratory epithelium of patients with chronic obstructive pulmonary disease or asthma. Having in mind the unified airway concept, it is also possible that these bacteria can cause persistent infection of sinus mucosa in patients with chronic rhinosinusitis. Sixty consecutive patients with chronic rhinosinusitis who underwent the functional endoscopic sinus surgery due to medical therapy failure were included in the study. During the operation, sinuses were irrigated with sterile 0.9% NaCl solution and this lavage was immediately aspirated. Aspirates were used for the detection of C. pneumoniae and M. pneumoniae DNA using real-time PCR. C. pneumoniae and M. pneumoniae DNA were not detected in samples analysed. Atypical bacteria C. pneumoniae and M. pneumoniae did not cause persistent infection of sinus mucosa in patients with chronic rhinosinusitis.

Low yield by molecular detection of Chlamydophila pneumoniae in respiratory samples in Belgium questioning its etiological role in respiratory tract infections

The actual burden of respiratory infections due to Chlamydophila pneumoniae is difficult to assess due to the major differences in positivity rates between PCR- and serology-based methods. The aim of the current study was to objectively analyse the yield of PCRs for the detection of C. pneumoniae in respiratory samples and to evaluate the additional value of performing laboratory diagnosis for C. pneumoniae in a setting of respiratory infection. The data based on routine analysis of respiratory samples with request for C. pneumoniae detection were collected from 4 large Belgian hospitals during 2 consecutive years. In total 3560 respiratory samples have been analysed and overall only 7 samples (0.2%) were found positive. Based on these observations, the critical evaluation of the actual role of C. pneumoniae in the etiology of lower respiratory infections and consequently of the extensive use of diagnostic tools for the detection of C. pneumoniae is needed.

Chlamydophila pneumoniae in human immortal Jurkat cells and primary lymphocytes uncontrolled by interferon-γ

Lymphocytes are a potential host cell for Chlamydophila pneumoniae, although why the bacteria must hide in lymphocytes remains unknown. Meanwhile, interferon (IFN)-γ is a crucial factor for eliminating chlamydiae from infected cells through indoleamine 2,3-dioxygenase (IDO) expression, resulting in depletion of tryptophan. We therefore assessed if lymphocytes could work as a shelter for the bacteria to escape IFN-γ. C. pneumoniae grew normally in human lymphoid Jurkat cells, even in the presence of IFN-γ or under stimulation with phorbol myristate acetate plus ionomycin. Although Jurkat cells expressed IFN-γ receptor CD119, their lack of IDO expression was confirmed by RT-PCR and western blotting. Also, C. pneumoniae survived in enriched human peripheral blood lymphocytes, even in the presence of IFN-γ. Furthermore, C. pneumoniae in spleen cells obtained from IFN-γ knockout mice with C57BL/6 background was maintained in a similar way to wild-type mice, supporting a minimal role of IFN-γ-related response for eliminating C. pneumoniae from lymphocytes. Thus, we concluded that IFN-γ did not remove C. pneumoniae from lymphocytes, possibly providing a shelter for C. pneumoniae to escape from the innate immune response, which has direct clinical significance.

Development and evaluation of a MAb-based ELISA for detection of Chlamydophila pneumoniae infection with variable domain 2 and 3 of the major outer membrane protein

OBJECTIVE

This paper aims to develop a monoclonal antibodies (MAbs)- based ELISA for detecting Chlamydophila pneumoniae (C. pneumoniae) antigens in humans with the variable domains (VD) 2 and 3 of the major outer membrane protein (MOMPVD2-VD3) and to assess its sensitivity and specificity by comparing with a widely used MAb that is able to recognize the elementary bodies of C. pneumoniae.

METHODS

MOMPVD2-VD3 were overexpressed in Escherichia coli and purified by affinity chromatography. Mice were immunized with the recombinant antigen, and hybridomas secreting MAbs were screened. Three stable hybridomas clones were selected and named 5D6, 7G3, and 8C9. The MAbs-based ELISA was scrutinized for species-specific recognition with a number of human throat swab samples from Group I (156 patients with typical respiratory illness clinically confirmed before) and Group II (57 healthy donors).

RESULTS

In Group I, 55 positive cases were detected by anti-EB MAb-based ELISA, 51 cases were positive by MAbs 5D6-based ELISA, and 33 and 38 cases were positive by MAb 8C9 and 7G3-based ELISA respectively. Of the 57 samples from Group II "healthy donors", 5 were positive and 52 were negative with both anti-EB and 5D6-based tests, while 2 and 3 positive cases were identified by the other two MAb-based ELISAs respectively.

CONCLUSION

The novel MOMPVD2-VD3 MAb-based assay may have higher specificity than the anti-EB MAb, which may possibly be used as an alternative tool for the diagnosis of C. pneumoniae infection.

[Contemporary risks of infections by Mycoplasma pneumoniae and Chlamydophila pneumoniae]

Atypical microorganisms, like Mycoplasma pneumoniae and Chlamydophila pneumoniae are common subject of studies because of caused diseases. In the last years, attention is paid on serious complications, which persistent infection of this atypical pathogens can cause and on the immunological body answer for them.

[Role of Chlamydia trachomatis and Chlamydophila pneumoniae in damage of eye posterior segment structures]

AIM

Study the ability of Chlamydia trachomatis and Chlamydophila pneumoniae to damage structures of eye posterior segment, features of development of such infectious process, its morphological and clinical characteristics.

MATERIALS AND METHODS

6 rabbits with confirmed absence of C. trachomatis, C. pneumoniae were used in the study. 3 animals were infected with C. trachomatis culture and 3 animals--with C. pneumoniae culture. Subconjunctival and intravitreal mode of infectious agent introduction were used, as well as instillation of its culture into conjunctival sac. Microbiological diagnostics included microscopy with direct immunofluorescence, culture method and determination of antibody titers. Infectious process was studied by using ophthalmologic methods and histological examination. Observation period was 4 months.

RESULTS

In all the animals a development of infectious process at early stages after the infection was confirmed. Conjunctivitis symptoms, inflammatory exudation into vitreous humor, chorioretinal inflammation loci, disorders in transparency of optical media and detachment of retina were clinical manifestations. In 2 animals infected with C. trachomatis severe panuveitis was noted. In 4 animals infectious process assumed subclinical characteristics (infection with both C. trachomatis or C. pneumoniae). In pathomorphologic studies data on the ability of C. trachomatis and C. pneumoniae to cause damage to cells of retina, pigment epithelium and choroid were obtained.

CONCLUSION

C. trachomatis and C. pneumoniae may play a significant role in pathology of vitreous humor, retina, pigment epithelium and choroid.

Chlamydia pneumoniae-specific IgE is prevalent in asthma and is associated with disease severity

Background

Several Chlamydia pneumoniae (Cp) biomarkers have been associated with asthma but Cp-specific IgE (Cp IgE) has not been investigated extensively. Our objective was to investigate Cp IgE in community adult asthma patients.

Methods

(1) Prevalence of Cp IgE (measured by immunoblotting) and Cp DNA (by polymerase chain reaction) in peripheral blood, and biomarker associations with asthma severity. (2) Case-control studies of Cp IgE association with asthma using healthy blood donor (study 1) and non-asthmatic clinic patient (study 2) controls.

Results

Of 66 asthma subjects (mean age 40.9 years, range 5–75, 59% male, 45% ever-smokers) 33 (50%) were Cp IgE positive and 16 (24%) were Cp DNA positive (P = 0.001 for association of Cp IgE and DNA). Cp IgE was detected in 21% of mild intermittent asthma v 79% of severe persistent asthma (test for trend over severity categories, P = 0.002). Cp IgE detection was significantly (P = 0.001) associated with asthma when compared to healthy blood donor controls but not when compared to clinic controls.

Conclusions

Half of this sample of community asthma patients had detectable IgE against C. pneumoniae. Cp IgE was strongly and positively associated with asthma severity and with asthma when healthy blood donor controls were used. These results support the inclusion of Cp IgE as a biomarker in future studies of infectious contributions to asthma pathogenesis.

Detection of the ompA gene of Chlamydophila pecorum in captive birds in Argentina

Bacteria belonging to the family Chlamydiaceae cause a broad spectrum of diseases in a wide range of hosts, including humans, other mammals and birds. However, very little is known about chlamydial infections in birds in our region. In the present study, we examined 28 clinically normal birds in illegal captivity that were confiscated in the province of C6rdoba, Argentina. The objective was to detect Chlamydophila spp. in cloacal swabs by genetic analysis of the ompA gene. Nested-PCR of the ompA gene identified five samples as Chlamydophila pecorum and the sequence analysis demonstrated the presence of the ompA gene of C. pecorum in these birds. On the other hand, Chlamydophila psittaci was not detected. These birds could be either asymptomatic reservoirs or subclinical carriers of C. pecorum. This is the first report of the detection of C. pecorum in Argentina.

The role of Chlamydia and Chlamydophila infections in reactive arthritis

Chlamydia trachomatis and Chlamydophila pneumoniae are human pathogens; the former being the etiologic agent for trachoma as well as a prevalent sexually transmitted bacterium, while C. pneumoniae is a respiratory pathogen responsible for community-acquired pneumonia. Patients with reactive arthritis show evidence of present or past Chlamydial infection. Chlamydia spp., has been strongly implicated as a triggering factor for reactive arthritis. We describe the simultaneous occurrence of C. pneumoniae and C. trachomatis infections in a subject with reactive arthritis. We suggest treatment for a patient with Chlamydia-associated arthritis to define a means by which persistent organisms can be induced to return to the active developmental cycle, thereby making them more accessible to antibiotic activity.

Within-population diversity of koala Chlamydophila pecorum at ompA VD1-VD3 and the ORF663 hypothetical gene

Infection of koalas by Chlamydophila pecorum is very common and causes significant morbidity, infertility and mortality. Fundamental to management of the disease is an understanding of the importance of multi-serotype infection or pathogen virulence in pathogenesis; these may need consideration in plans involving koala movement, vaccination, or disease risk assessment. Here we describe diversity of ompA VD1-3, and ORF663 hypothetical gene tandem repeat regions, in a single population of koalas with diverse disease outcomes. We PCR amplified and sequenced 72 partial ompA segments and amplified 25 tandem repeat segments (ORF663 hypothetical gene) from C. pecorum obtained from 62 koalas. Although several ompA genotypes were identified nationally, only one ompA genotype existed within the population studied, indicating that severe chlamydial disease occurs commonly in free-ranging koalas in the absence of infection by multiple MOMP serotypes of C. pecorum. In contrast, variation in tandem repeats within the ORF663 hypothetical gene was very high, approaching the entire range reported for pathogenic and non-pathogenic C. pecorum of European ruminants; providing an impetus for further investigation of this as a potential virulence trait.

Analysis of Chlamydia pneumoniae infection in mononuclear cells by reverse transcription-PCR targeted to chlamydial gene transcripts

Chlamydia pneumoniae (C. pneumoniae) is an important etiological agent of respiratory infections including pneumonia. C. pneumoniae DNA can be detected in peripheral blood mononuclear cells indicating that monocytes can assist the spread of infection to other anatomical sites. Persistent infection established at these sites could promote inflammation and enhance pathology. Thus, the mononuclear cells are in a strategic position in the development of persistent infection. To investigate the intracellular replication and fate of C. pneumoniae in mononuclear cells, we have established an in vitro model in the human Mono Mac 6 cell line. In the present study, we analyzed the transcription of 11 C. pneumoniae genes in Mono Mac 6 cells during infection by real-time RT-PCR. Our results suggest that the transcriptional profile of the studied genes in monocytes is different from that seen in epithelial cells. Furthermore, our study shows that genes related to secretion are transcribed, and secreted bacterial proteins are also translated during infection of monocytes, creating novel opportunities for the management of chlamydial infection of monocytes.

[Promoting effect of Chlamydia pneumoniae infection on human laryngeal carcinoma HEp-2 cell adhesion and migration]

OBJECTIVE

To explore the effect of Chlamydia pneumoniae (C.pn) infection on human laryngeal carcinoma cell line HEp-2 cell adhesion and migration, to further clarify the role and mechanism of C.pn infection in tumor metastasis.

METHODS

HEp-2 cells were infected with C.pn after the culture and propagation of C.pn. The cytopathic effect was observed by microscopy. Morphological characteristics of C.pn inclusions in HEp-2 cells were examined by fluorescence microscopy and acridine orange staining. The ultrastructural changes of C.pn inclusions in the HEp-2 cells were examined by transmission electron microscopy (TEM). Cell adhesion assay was performed to investigate the effect of C.pn infection on the adhesion of HEp-2 cells to collagen I. Wound-healing assay and transwell assay were performed to explore the effect of C.pn infection on HEp-2 cell migration.

RESULTS

At 72 h post-infection, C.pn infected-HEp-2 cells were swollen and partially desquamated. Numerous vacuoles (inclusions) were observed and C.pn inclusions occupied almost the whole cytoplasm of the HEp-2 cells. Grape-like C.pn inclusions were observed in the HEp-2 cells stained with acridine orange under a fluorescence microscope at 72 h after infection. Under TEM, there were more mature pear-shaped elementary bodies, but less larger and round reticulate bodies in the HEp-2 cells infected with C.pn for 72 h. In the cell adhesion assay, the A value in C.pn infection group was 0.669 ± 0.011, significantly higher than that in the control group (0.558 ± 0.005) at 2 h after infection (P < 0.001). The cell adhesion ratio in the C.pn infection group was 119.89%. The migration distance of C.pn infected-HEp-2 cells in the wound-healing assay was significantly longer than that of control cells at 24 h after infection (P < 0.05). HEp-2 cells infected with C.pn for 12 h migrated more than the control cells in the transwell assay (23.40 ± 2.41 vs 10.40 ± 1.67) (P < 0.001).

CONCLUSIONS

C.pn infection can significantly promote HEp-2 cell adhesion to collagen I and migration of HEp-2 cells, indicating that C.pn infection may play an important role in promoting the metastasis of laryngeal cancer.

[The phylogenetic position of Chlamydia strains isolated from monkeys and humans with Chlamydial pathology in the family Chiamydiaceae. Genotypic and phenotypic properties of this pathogen]

Based on the results of the comparative analysis concerning relatedness and evolutional difference of the 16S - 23S nucleotide sequences of the middle ribosomal cluster and 23S rRNA I domain, and based on identification of phylogenetic position for Chlamydophila pneumoniae and Chlamydia trichomatis strains released from monkeys, relatedness of the above stated isolates with similar strains released from humans and with strains having nucleotide sequences presented in the GenBank electronic database has been detected for the first time ever. Position of these isolates in the Chlamydiaceae family phylogenetic tree has been identified. The evolutional position of the investigated original Chlamydia and Chlamydophila strains close to analogous strains from the GenBank electronic database has been demonstrated. Differences in the 16S - 23S nucleotide sequence of the middle ribosomal cluster and 23S rRNA I domain of plasmid and non-plasmid Chlamydia trachomatis strains released from humans and monkeys relative to different genotype groups (group B- B, Ba, D, Da, E, L1, L2, L2a; intermediate group - F, G, Ga) have been revealed for the first time ever. Abnormality in incA chromosomal gene expression resulting in Chlamydia life and development cycle disorder and decrease of Chlamydia virulence can be related to probable changes in the nucleotide sequence of the gene under consideration.

[Chlamydophila pneumoniae infections in younger children. Experience of one centre. Preliminary report]

BACKGROUND

Very few recent Polish data are available on the epidemiology of Chlamydophil pneumoniae (C. pneumoniae) as causative agent among paediatric patients, hospitalized with respiratory tract disorders. Extending these data would serve as rationale for empirical antimicrobial therapy. The aim of the study was to evaluate the frequency of C. pneumoniae infections in younger children hospitalized with prolonged cough and/or prolonged pneumonia.

MATERIAL AND METHODS

110 children, aged 0.3-7.0 yrs., hospitalized from January 1st to March 3 1st 2009 for the above reasons were retrospectively enrolled in the study. Diagnosis of C. pneumoniae was based on ELISA IgM antibodies positive test. Patients with ambiguous IgM titre were excluded from further study (n=12).

RESULTS

Of 98 finally investigated children, C. pneumoniae infection was found in 28 patients (28.5%) with the highest frequency in February 2009 (15 cases). It was diagnosed more frequentlyin toddlers (over 1.73 yrs. of age) than in infants and youngest children (p=0,014; OR=4,10 95%C1=1,4-12,0). In patients with active C pneumoniae infection WBC were significantly lower (p=0,001), but within normal range (8647/mm3, +/- SD: 3247/mm3). Other factors such as sex, clinical symptoms and some chosen laboratory markers did not differ significantly between subgroups of sero-positive/sero-negative patients.

CONCLUSIONS

Performed analysis suggests a significant role of C. pneumoniae etiology in younger children with prolonged respiratory tract symptoms and can be a useful tool in empirical antibacterial treatment. Further studies for a longer period, larger groups of patients and additional confirmation of sero-positive cases are needed.

[Retinal lesion in experimental chlamydia eye infection]

Until the present time, ophthalmic chlamydiasis has been generally associated with diseases of auxiliary organs of the eye and its anterior segment: conjunctivitis and iridocyclitis. The morphological substrate of eye posterior segment lesion caused by C. trachomatis and C. pneumonia was studied in this investigation. The pathomorphological pattern characteristic of chlamydia-induced rabbit retinal and vitreous body lesions is composed of vitreoretinal lymphocyte-macrophageal infiltrations of varying intensity, posterior hyaloid membrane detachment, peripheral foci or folding of the retina, impaired nuclei of photoreceptors and bipolar neurons, pigment epithelial damage occurring in different concurrences in relation to the species of a causative agent and the clinical picture.

Chlamydophila felis: plasmid detection in Italian isolates

Plasmids have been detected in the majority of strains in the genus Chlamydia and in many Chlamydophila species. Previous studies showed that FP Pring and FP Cello Chlamydophila felis strains have an extrachromosomial plasmid, whereas the FP Baker strain does not. Azuma et al. recently sequenced the entire genomic DNA sequence of the Japanese Cp. felis strain Fe/C-56 and described a 7,552 base pair circular plasmid. In the present study a highly conserved plasmid gene was detected in 11 Italian Cp. felis isolates, showing 100% nucleotide identity with the plasmid gene of Fe/C-56 Cp. felis strain.

[The implication of Chlamydia pneumoniae in damage to human aortic endotheliocytes in atherosclerosis]

A cytological technique was used to study the impressions of the aortic intima of dead patients. Endothelial cell Chlamydia pneumoniae (CP) was detected in 26 (56.5%) of 46 dead patients; the bacterium was found in the unaffected intact intimal areas in 9 (19.6%) cases. Three morphological forms of CP--inclusions, spots, and aggregates were described. The whole life cycle of CP and the specific features of disintegration of the host cell--the endothelium were observed. CP leads to extensive infection and aponecrotic death of all types of endothelial cells above the fatty streaks and plaques. Focal chlamydial destruction of an endothelial layer results in intimal surface erosion and thrombogenesis. An inflammatory response to damaged endothelial cells may be responsible for the initiation and progression of atherosclerosis and plaque destabilization.

Production and purification of low calcium response protein H of Chlamydophila pneumoniae

Chlamydophila pneumoniae possesses a type III secretion system (TTSS), which allows the bacteria to secrete effector molecules into the inclusion membrane and into the cytosol of the host cell. Low calcium response protein H (LcrH), as a part of the TTSS, is a chaperone protein expressed from the middle to late stages of the chlamydial developmental cycle. Gene of LcrH (CPn0811) in a 6His-tagged form was cloned from C. pneumoniae CWL029, expressed and purified from Escherichia coli using the HIS-select TALON CellThru Resin. The purity was checked with mass spectrometry. The samples were used for immunization of BALB/c mice. The inducible E. coli clone, which over-expresses the chlamydial LcrH, permits the study of the biological properties of this protein.

[Effector proteins of Clamidia]

The review summarizes the recent published data on molecular mechanisms of Chlamidiae - host cell interaction, first of all on chlamydial effector proteins. Such proteins as well as III transport system proteins that transfer many effector proteins into host cytoplasm are attractive targets for drug therapy of chlamydial infections. The majority of the data concerns two species, Chlamydia trachomatis and Chlamydophila pneumoniae. C. trachomatis protein TARP, which is presynthesized in elementary bodies, plays an essential role in the initial stages of the infection. Patogen proteins participating in the next stage, that is the intracellular inclusion traffic to the centrosome, are CT229 of C. trachomatis and Cpn0585 of C. pneumoniae, which interact with cellular Rab GTPases. In C. trachomatis, IncA protein plays a key role in chlamydial inclusions fusion, CT847 modulates life cycle of the host cell, LDA3 is essential in acquisition of nutrients. CPAF protease and inclusion membrane proteins IncG and CADD participate in suppression of apoptosis of infected cells. The proteases CPAF and CT441, as well as deubiquitinating ChlaDub1 protein, contribute to avoiding the immune response.

[Relationship between primary ocular adnexal mucosa-associated lymphoid tissue lymphoma and eye infection]

OBJECTIVE

To study the role of pathogenic microorganisms commonly associated with chronic eye disease, including Chlamydia psittaci, Chlamydia trachomatis, Chlamydia pneumoniae, herpes simplex virus (HSV) type 1 and type 2, and adenovirus type 8 and type 19, in the development of primary ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphoma in Chinese patients.

METHODS

Sixty-eight archival cases of primary ocular adnexal lymphoproliferative lesions, including 38 cases of MALT lymphoma, 3 cases of non-MALT lymphoma and 27 cases of chronic inflammation, were enrolled into the study. DNA was extracted from the paraffin-embedded tissue samples. The presence of DNA of C. psittaci, C. trachomatis, C. pneumoniae, HSV type 1, HSV type 2, adenovirus type 8 and adenovirus type 19 were analyzed by multiplex touchdown enzyme time-release polymerase chain reaction (TETR-PCR).

RESULTS

All of the specimens yielded PCR products of over 100 base pairs and were thus suitable for TETR-PCR screening of infectious agents. The prevalence of DNA of C. psittaci, C. trachomatis and adenovirus type 19 were 0 in MALT lymphoma, non-MALT lymphoma and chronic inflammation. There were 2 cases positive for C. pneumoniae DNA, amongst the 38 cases of MALT lymphoma studied (5.3%, 2/38). HSV type 1, HSV type 2 and adenovirus type 8 DNA was found in each of the 3 patients with chronic inflammation.

CONCLUSION

The study indicates that C. psittaci, C. trachomatis, C. pneumoniae, HSV type 1, HSV type 2, adenovirus type 8 and adenovirus type 19 probably play little role in the pathogenesis of ocular adnexal MALT lymphoma in Chinese patients.

Chlamydophila pneumonia: Specific mRNA in aorta ascendens in patients undergoing coronary artery by-pass grafting

The objective of this prospective study was to investigate if Chlamydophila pneumoniae (Cp)-specific DNA and mRNA are present in tissue samples from the wall of aorta ascendens in patients undergoing by-pass surgery for coronary artery disease (CAD) that includes stable angina pectoris (SAP, 25 patients) and acute coronary syndrome (ACS, 19 patients). Viable Cp was detected in 8/44 (18%) patients using reversed transcriptase PCR (RT-PCR) against bacterial mRNA with detection of cDNA using real-time PCR against the MOMP gene. Cp DNA was detected by nested PCR in 22/44 (50%) patients and by real-time PCR in 13/44 (30%) patients. In total, 24/44 (55%) patients were positive for Cp nucleic acid in any PCR. Antibodies to Cp were detected in 13/24 (54%) Cp PCR-positive and in 15/20 (75%) Cp PCR-negative patients. Nested PCR was run on throat swabs from all patients. No significant differences were noted between SAP and ACS patients regarding PCR results or serology. It has been suggested that Cp may be a 'silent passenger' picked up by the atherosclerotic plaque. Our findings of viable and metabolically active bacteria in aortic tissue add further support to the hypothesis that Cp may have an active role in the pathogenesis of atherosclerosis.

Preeclampsia and Chlamydia Pneumoniae: Is There a Link?

Several parallels exist between preeclampsia and atherosclerosis. Both are multifactorial diseases that share risk factors such as obesity, insulin resistance, lipid abnormalities, and elevated serum homocysteine. There are also similarities in the biochemical changes seen in both diseases, including elevated serum triglycerides, decreased HDL cholesterol and enhanced formation of small, dense LDL particles as well as vascular atherosclerotic lesions. Chronic infection with Chlamydia pneumoniae has been linked to coronary artery disease. This study evaluated a possible link between the incidence of preeclampsia and infection with C. pneumoniae by examining the rate of seropositivity in 81 women with preeclampsia, and 206 women with normal pregnancies. Although our data confirmed well-known risk factors for preeclampsia such as obesity, diabetes, and hypertension, we found no difference in the rate of seropositivity between preeclampsia and normal pregnancy. On the contrary, the presence of chlamydial antibodies was lower in preeclampsia. Multiparous women with preeclampsia showed a significantly lower rate of seropositivity than multiparous normal women and nulliparous preeclamptics. In addition, women with a history of preeclampsia who developed preeclampsia in the current pregnancy also had a significantly lower rate of seropositivity.

[Chlamydophila pneumoniae: from its proteomics to arteriosclerosis]

Chlamydophila pneumoniae is a highly prevalent intracellular human pathogen with a unique biphasic life cycle. It is a common cause of upper respiratory infection and pneumonia, and is currently being studied as a potential risk factor for the development of atherosclerotic cardiovascular disease. The outer membrane surface antigens of C. pneumoniae are highly complex: some, such as the major outer membrane protein, are specific, but poorly immunodominant, whereas others have stronger immunogenicity, but are cross-reactive among Chlamydia species. Therefore, new, highly immunodominant, species-specific antigens should be sought. In this regard, the polymorphic membrane proteins (PMPs) are a) unique to Chlamydiae, b) often exposed on the surface of the bacteria, and c) highly immunogenic; these factors make them potential candidates for application in laboratory assays. Other chlamydial antigens, such as heat shock protein (HSP) 60, have been associated with atherosclerotic lesions because of their ability to induce an immunological attack on the endothelial wall. Over the last decade, several studies have suggested a potential role of chronic C. pneumoniae infection in human atherosclerosis. Nevertheless, prospective studies with sufficiently large samples and a healthy comparison group, using a combination of direct and indirect microbiological techniques in the same subject and sample, are needed to establish a relationship between the infection and disease activity.

Detection of Chlamydia pneumoniae in atherosclerotic plaques of patients in Tehran, Iran

Persistent infection of arteries with organisms such as Chlamydia pneumoniae was previously found to contribute to the development of atherosclerosis. We investigate the presence of C. pneumoniae in atherosclerotic plaque by polymerase chain reaction and direct immunofluorescence assay, and we examine the correlation between clinical status and the presence of this bacterium in Iran. The study group consisted of 33 atherosclerotic plaque specimens from the arteries (26 coronary and 7 abdominal aorta) of patients who had undergone coronary artery bypass grafting surgery (CABG). The control group consisted of 31 specimens: 12 from biopsies of macroscopically healthy regions of the ascending aorta in patients who had undergone CABG and 19 autopsy specimens of normal coronary arteries. C. pneumoniae DNA and antigen were found in 6 (18%) and 7 (21%) of 33 endarterectomy specimens, respectively. C. pneumoniae was not detected in the control group by either method. The presence of C. pneumoniae in atherosclerotic plaques and its absence in healthy vessels supports the idea that C. pneumoniae may have a role in the development of atherosclerosis, especially in countries where infection is prevalent and where conventional risk factors fail to explain the exact reason for the high prevalence of atherosclerotic vascular disease.

Chlamydophila pneumoniae myopericarditis in a child

An 11-year-old boy with serologically confirmed Chlamydophila pneumoniae infection presented with clinical, laboratory, and echocardiographic changes consistent with myopericarditis. No reports on C. pneumoniae myopericarditis in children are found in the medical literature. The boy, previously healthy, presented with fever, rash, constitutional symptoms, elevated acute phase reactants, elevated cardiac enzymes, and high brain natriuretic peptide levels. Hemodynamic instabilities, including hypotension and mild hypoxia, were noted. Two-dimensional echocardiographic findings showed mildly depressed left ventricular systolic function and small pericardial effusion. Requiring inotropic support, the boy was treated with azithromycin 10 mg/kg once daily for 7 days and a single dose of intravenous immunoglobulin 2 g/kg. He recovered fully with improved left ventricular systolic function before hospital discharge. An early definitive diagnosis is essential to knowing the etiology of pediatric myocarditis. Specific therapy may play role in the management and prognosis of this disorder.

Amalgamation of Chlamydia pneumoniae inclusions with lipid droplets in foam cells in human atherosclerotic plaque

Chlamydia pneumoniae (Chlamydophila pneumoniae) infect macrophages and accelerates foam cell formation in in vitro experiments, but whether this might occur in human atherosclerosis is unknown. In the present study, we examined 17 carotid artery segments, obtained by endarterectomy, in which the presence of C. pneumoniae was confirmed by both polymerase chain reaction and immunohistochemistry. Electron microscopy demonstrated the presence of structures with the appearance of elementary, reticulate and aberrant bodies of C. pneumoniae in the cytoplasm of macrophage foam cells. The volume of the cytoplasm that was free from vacuoles and lipid droplets in C. pneumoniae-infected foam cells was dramatically reduced, and a phenomenon of the amalgamation of C. pneumoniae inclusions with lipid droplets was detected. Double immunohistochemistry showed that C. pneumoniae-infected foam cells contained a large number of oxidized low-density lipoproteins. The observations provide support to the hypothesis that C. pneumoniae could affect foam cell formation in human atherosclerosis.

Chlamydia pneumoniae infection and hyperlipidaemia-induced expression of P50 and c-Fos in the heart of C57BL6J mice

OBJECTIVE

The objective of this study was to investigate infection by Chlamydia pneumoniae (C. pneumoniae) and the combined effects of an atherogenic diet on the expression of AP-1 or the subunit of AP-1 (c-Fos) and NF-kappaB or the subunit of NF-kappaB (P50) in myocardial cells of C57BL/6J mice.

METHODS AND RESULTS

Thirty-six 8-week-old female C57BL/6J mice were divided into three groups: A, B and C (twelve mice in each group). Mice in group A were fed an atherogenic diet (consisting of 15% fat and 2.5% cholesterol). Those in group B and C (as blank control) were fed a regular diet. The mice in group B were infected with C. pneumoniae. Fourteen weeks later, the expression of P50 (subunit of NF-kappaB) and c-Fos (subunit of AP-1) in the heart was determined by indirect immunofluorescence in the myocardial cells. Binding activity of NF-kappaB and AP-1 in the heart was determined by electrophoretic mobility shift assay (EMSA). The expression of NF-kappaB and AP-1 in the myocardial cells was upregulated in group A and B, compared with group C (P < 0.05). There was no significant difference between group A and B.

CONCLUSION

The inflammatory process was already initiated in the myocardial cells in C57BL/6J mice at the early stage of C. pneumoniae infection and hyperlipidaemia. The expression of NF-kappaB and AP-1 was upregulated in mice infected by C. pneumoniae or fed an atherogenic diet. C. pneumoniae or hyperlipidaemia may involve the pathogenesis and progression of ischaemic cardiomyopathy.

Prevalence of Mycoplasma and Chlamydia pneumonia in severe community-acquired pneumonia among hospitalized children in Thailand

Pneumonia is the leading cause of pediatric morbidity and mortality worldwide, and Mycoplasma pneumoniae and Chlamydia pneumoniae are the two most common atypical pathogens. This study was designed to determine the prevalence and clinical impact of mycoplasma and chlamydia pneumonia in children hospitalized with severe pneumonia. Children 1 month-15 years old with a diagnosis of severe pneumonia (WHO criteria) were recruited between March 2005 and March 2006. Serologic studies were performed for anti-M. pneumoniae and anti-C. pneumoniae IgG/M on admission and 2-4 weeks afterward using ELISA. Of 52 patients, 13 (25%) were positive for Mycoplasma, 8 (15%) were positive for Chlamydia, 4 (7.6%) were positive for a mixed infection and 27 (52%) were negative. The subjects' mean age was 23.8+/-4.1 months. The mean of initial oxygen saturation on admission was 87.5+/-1.2%. Fever and prolonged cough were the leading symptoms. The mean of hospitalization was 18.8+/-2.6 days, chlamydia pneumonia had the longest duration, 30+/-10.2 days and 13/52 (25%) study subjects developed respiratory failure. Only 10% were treated with adequate antibiotic prior to serologic results. There was one mortality (1/52, 2%). Our study suggests that mycoplasma and chlamydia infections are commonly found among children hospitalized with severe pneumonia. Coverage with an appropriate antibiotic should be considered to hasten recovery.

Infection and atherosclerosis. An alternative view on an outdated hypothesis

Already at the beginning of the 20th century, a potential role for microbes in vascular diseases was suggested. However, until the late '70 of that century, not much attention has been paid to this infection hypothesis. Then, predominantly based on the pioneering work of Fabricant et al., evidence for a contributing or even initiating role for microbes in atherosclerosis, as well as other vascular diseases, was accumulating. Also, the seminal paper by Saikku and co-workers, demonstrating serological evidence of an association of Chlamydia pneumoniae, an obligate intracellular respiratory gram-negative bacterium, with chronic coronary heart disease and acute myocardial infarction, significantly boosted the research on the infection hypothesis. Since then, numerous papers have been published demonstrating associations between a large variety of pathogens and atherosclerotic disease. Furthermore, many molecular mechanisms have been suggested by which microbes may affect atherogenesis. Nevertheless, in recent large randomised prospective trials, evaluating the efficacy of antibiotic treatment for the secondary prevention of coronary events, no reduction in the rate of cardiovascular events was observed, thereby seriously challenging the validity of the infection hypothesis. Nevertheless, the large body of supporting evidence, which has accumulate over the past decades, should not be ignored and maybe we should look at the hypothesis, and in particular the mechanisms by which microbes affect the disease, from a different angle.