Showing papers on "Chlamydia psittaci published in 1999"

Emended description of the order Chlamydiales, proposal of Parachlamydiaceae fam. nov. and Simkaniaceae fam. nov., each containing one monotypic genus, revised taxonomy of the family Chlamydiaceae, including a new genus and five new species, and standards for the identification of organisms.

Abstract: The current taxonomic classification of Chlamydia is based on limited phenotypic, morphologic and genetic criteria This classification does not take into account recent analysis of the ribosomal operon or recently identified obligately intracellular organisms that have a chlamydia-like developmental cycle of replication Neither does it provide a systematic rationale for identifying new strains In this study, phylogenetic analyses of the 16S and 23S rRNA genes are presented with corroborating genetic and phenotypic information to show that the order Chlamydiales contains at least four distinct groups at the family level and that within the Chlamydiaceae are two distinct lineages which branch into nine separate clusters In this report a reclassification of the order Chlamydiales and its current taxa is proposed This proposal retains currently known strains with > 90% 16S rRNA identity in the family Chlamydiaceae and separates other chlamydia-like organisms that have 80--90% 16S rRNA relatedness to the Chlamydiaceae into new families Chlamydiae that were previously described as ‘Candidatus Parachlamydia acanthamoebae’ Amann, Springer, Schonhuber, Ludwig, Schmid, Muller and Michel 1997, become members of Parachlamydiaceae fam nov, Parachlamydia acanthamoebae gen nov, sp nov ‘Simkania’ strain Z becomes the founding member of Simkaniaceae fam nov, Simkania negevensis gen nov, sp nov The fourth group, which includes strain WSU 86--1044, was left unnamed The Chlamydiaceae, which currently has only the genus Chlamydia, is divided into two genera, Chlamydia and Chlamydophila gen nov Two new species, Chlamydia muridarum sp nov and Chlamydia suis sp nov, join Chlamydia trachomatis in the emended genus Chlamydia Chlamydophila gen nov assimilates the current species, Chlamydia pecorum, Chlamydia pneumoniae and Chlamydia psittaci, to form Chlamydophila pecorum comb nov, Chlamydophila pneumoniae comb nov and Chlamydophila psittaci comb nov Three new Chlamydophila species are derived from Chlamydia psittaci: Chlamydophila abortus gen nov, sp nov, Chlamydophila caviae gen nov, sp nov and Chlamydophila felis gen nov, sp nov Emended descriptions for the order Chlamydiales and for the family Chlamydiaceae are provided These families, genera and species are readily distinguished by analysis of signature sequences in the 165 and 235 ribosomal genes

Computational Analysis of the Polymorphic Membrane Protein Superfamily of Chlamydia trachomatis and Chlamydia pneumoniae

Abstract: Whole sequence genome analysis is invaluable in providing complete profiles of related proteins and gene families. The genome sequences of the obligate intracellular bacteria Chlamydia trachomatis and Chlamydia pneumoniae both encode proteins with similarity to several 90-kDa Chlamydia psittaci proteins. These proteins are members of a large superfamily, C. trachomatis with 9 members and C. pneumoniae with 21 members. All polymorphic membrane proteins (Pmp) are heterogeneous, both in amino acid sequence and in predicted size. Most proteins have apparent signal peptide leader sequences and hence are predicted to be localized to the outer membrane. The unifying features of all proteins are the conserved amino acid motifs GGAI and FXXN repeated in the N-terminal half of each protein. In both genomes, the pmp genes are clustered at various locations on the chromosome. Phylogenetic analysis suggests six related families, each with at least one C. trachomatis and one C. pneumoniae orthologue. One of these famil...

Prevalence of feline Chlamydia psittaci and feline herpesvirus 1 in cats with upper respiratory tract disease

Abstract: The epidemiology of feline chlamydiosis and feline herpesvirus 1 (FHV1) infection in cats was determined using a duplex polymerase chain reaction assay. In cats with upper respiratory tract disease (URTD), prevalences of 66 (14.3%) of 462 cats and 98 (21.2%) of 462 cats were found for Chlamydia psittaci and FHV1, respectively. In cats without URTD, prevalences were 1/87 (1.1%) for both pathogens. Younger cats, cats sampled in summer, and cats with conjunctivitis were more likely to be positive for C psittaci than were cats sampled in other seasons and cats without conjunctivitis. Cats with recent contact with cats outside the household, cats with acute disease, and sneezing cats were more likely to be positive for FHV1 than were cats that had not had recent contact with cats outside the household, cats with chronic disease, and cats that were not sneezing. Purebred cats were less likely to be positive for FHV1 than were mixed breed cats and prevalence varied with year of sampling. Coinfection with both pathogens was lower than would be expected from their respective prevalences. Vaccinated cats were equally likely to be positive for FHV1 as unvaccinated cats. In sneezing cats FHV1 was more likely to be detected than C psittaci, particularly in acute cases, and when sneezing was not accompanied by conjunctivitis. Cats with reproductive disease concurrent with URTD were more likely to be infected with FHV1 than with C psittaci. Thus, the factors that should be considered in clinical diagnoses of C psittaci infections are the presence of conjunctivitis, age, and season, whereas contact with other cats, acute disease, and sneezing should be considered in diagnoses of FHV1 infection.

Turkeys are protected from infection with Chlamydia psittaci by plasmid DNA vaccination against the major outer membrane protein.

Abstract: Plasmid DNA expressing the major outer membrane protein (MOMP) of an avian Chlamydia psittaci serovar A strain has been tested for its ability to raise an immune response and induce protection against challenge with the same serovar. A combined parenteral (intramuscular injection) and mucosal route (DNA drops administered to the nares) of DNA inoculation was compared with gene gun-based immunization. The gene gun delivery of pcDNA1/MOMP as well as the intramuscular-intranasal DNA delivery primed both T-helper and B cell memory, although rMOMP-expressing cells did not induce high antibody responses. Evidence for the priming of the memory was provided by the fact that the pcDNA1/MOMP inoculations raised antibodies belonging to the IgG and not IgM isotype. However, in response to challenge only five out of 15 vaccinated turkeys showed four-fold increases in serum IgG after challenge. By contrast, evidence for the priming of T cell memory in response to challenge was found in all vaccinated turkeys, as shown by the significantly heightened proliferative responses of peripheral blood lymphocytes following vaccination. Both immunization methods produced similar serological and lymphocyte proliferative responses. Notwithstanding the immunization method, a significant level of protection was observed in all pcDNA1/MOMP-immunized turkeys. The efficacy of MOMP-based DNA vaccination as a means of preventing severe clinical signs, lesions and chlamydia excretion in a turkey model of C. psittaci infection was demonstrated.

Identification of Two Novel Genes Encoding 97- to 99-Kilodalton Outer Membrane Proteins of Chlamydia pneumoniae

Abstract: Two genes encoding 97- to 99-kDa Chlamydia pneumoniae VR1310 outer membrane proteins (Omp4 and Omp5) with mutual similarity were cloned and sequenced. The proteins were shown to be constituents of the C. pneumoniae outer membrane complex, and the deduced amino acid sequences were similar to those of putative outer membrane proteins encoded by the Chlamydia psittaci and Chlamydia trachomatis gene families. By use of a monospecific polyclonal antibody against purified recombinant Omp4, it was shown that without heating, the protein migrated at 65 to 75 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoelectron microscopy showed that epitopes of Omp4 were exposed on the surface of C. pneumoniae elementary bodies, reticulate bodies, and outer membrane complex. Proteins encoded by the C. pneumoniae gene family seem to be dominant antigens in experimentally infected mice.

IL-12 Administered During Chlamydia psittaci Lung Infection in Mice Confers Immediate and Long-Term Protection and Reduces Macrophage Inflammatory Protein-2 Level and Neutrophil Infiltration in Lung Tissue

Abstract: Protection against infections with the intracellular bacterium Chlamydia spp. requires Th1-polarized CD4+ T cell immunity. In BALB/c mouse lung infections, immediate innate and nascent Chlamydia-specific immune responses following intranasal inoculation of Chlamydia psittaci strain B577 were modulated by 7-day i.p. administration of murine rIL-12, the initiation cytokine for Th1 immunity. Treatment with IL-12 reduced the severity of chlamydial pneumonia, abolished mortality (37.5% in untreated mice), and significantly reduced numbers of chlamydial organisms in lungs. On day 4 after inoculation, the neutrophil:macrophage ratio in bronchointerstitial pneumonias was 1.96 in untreated mice and 0.51 in IL-12-treated mice. This immediate, IL-12-mediated shift in innate inflammatory phenotype was correlated with a significant reduction of lung concentrations of the neutrophil chemoattractant macrophage inflammatory protein (MIP)-2 (putative murine homologue of human IL-8), monocyte chemotactic protein-1, and TNF-alpha; and a reduction in MIP-1alpha and IFN-gamma, at high-dose infection only, and IL-12-independent IL-10 levels. Chlamydia-specific Ab titers and Ig isotype ratios indicated an IL-12-dependent Th1 shift. Recall responses of IL-12-primed mice to secondary chlamydial lung infection eliminated chlamydiae more effectively and generated a lung cytokine profile conducive to perpetuation of the Th1 memory population. These data support the hypothesis that genetic differences in endogenous IL-12 production and response pathways could determine disease outcomes characterized by poor chlamydial clearance and a purulent inflammatory infiltrate vs effective elimination of chlamydiae in a macrophage-dominated response.

Brief reports Comparative in-vitro activity of moxifloxacin, minocycline and azithromycin against Chlamydia spp.

Abstract: The in-vitro activity of moxifloxacin, a new 8-methoxyquinolone, was compared with minocycline and azithromycin against 40 strains of Chlamydia trachomatis, Chlamydia pneumoniae and Chlamydia psittaci. Both the MIC and the MBC of moxifloxacin ranged from 0.03 to 0.125 mg/L. MICs of minocycline ranged from 0.015 to 0.06 mg/L and MBCs between 0.03 and 0.25 mg/L. MICs of azithromycin ranged from 0.03 to 0.125 mg/L and the MBCs between 0.06 and 0.5 mg/L. MBC values of moxifloxacin were the same as MICs in 32 (80%) of 40 strains tested, whereas those of minocycline and azithromycin were two to four times higher than their MICs. These data confirm those previously obtained indicating that quinolones kill chlamydial strains at concentrations equivalent to their MICs.

Multiplex polymerase chain reaction for the simultaneous detection of Mycoplasma pneumoniae, Chlamydia pneumoniae, and Chlamydia psittaci in respiratory samples.

Abstract: AIMS: To develop a multiplex polymerase chain reaction (PCR) for the simultaneous detection of Mycoplasma pneumoniae, Chlamydia pneumoniae, and Chlamydia psittaci in respiratory samples. METHODS: Oligonucleotide primers for the amplification of the DNA of these three organisms were optimised for use in combination in the same reaction. PCR products were detected by hybridisation with pooled internal probes using an enzyme linked immunosorbent assay. Those with positive signals were further differentiated using species specific probes. Quality of DNA extraction and PCR inhibition were controlled by amplification of a human mitochondrial gene. A panel of 53 respiratory samples with known results was evaluated blindly. This was followed by a retrospective study on sputa collected from 244 patients with suspected community acquired pneumonia. RESULTS: The multiplex assay had a lower sensitivity than PCR with individual primers by about one log. The resultant sensitivity was considered acceptable for diagnostic use. Of the panel of 53 samples, nine of 11 M pneumoniae, 11 of 11 C pneumoniae, six of seven C psittaci, and 24 of 24 negative samples were correctly identified. Of the 244 patients with pneumonia, seven (2.9%) had detectable M pneumoniae, six (2.5%) had C pneumoniae, and one (0.4%) had C psittaci. The case notes from 11 patients were studied. The PCR finding was of possible significance in at least eight of these patients. CONCLUSIONS: This multiplex PCR assay has the potential to be used as a diagnostic and epidemiological tool. Further prospective studies are needed to establish its clinical value.

Microbial Aetiology of Community-Acquired Pneumonia in Hospitalised Patients

Abstract: Adult patients hospitalised with community-acquired pneumonia were studied prospectively to determine the microbial aetiology of pneumonia. Between April 1996 and March 1997, blood and sputum samples were collected for culture. Throat swabs were obtained for isolation of viruses and for detection of antigens of Chlamydia pneumoniae, influenza viruses A and B, respiratory syncytial virus and parainfluenza virus. Antibodies against Legionella spp., Mycoplasma pneumoniae, Chlamydia pneumoniae, Chlamydia psittaci, Coxiella burnetii, influenza viruses A and B, respiratory syncytial virus, adenovirus and parainfluenza virus were tested in serum samples. Two hundred eleven patients were included in the study; paired sera were available from 152 patients. Blood culture was positive in 23 (10.9%) patients, Streptococcus pneumoniae being the bacterium isolated most frequently. A fourfold or greater rise or fall in the Chlamydia pneumoniae IgG and/or IgM antibody titre was found in 20 (9.5%) patients and a high antibody titre (> or = 1:512) in the first and/or the second serum sample in 18 (18.5%) patients. Antibodies confirming acute Mycoplasma pneumoniae infection were found in 12 (5.7%) patients, Legionella spp. in six (2.8%), Chlamydia psittaci in two and Coxiella burnetii in one. Three patients had pulmonary tuberculosis. Only two patients had a virus present in the throat swab (adenovirus in one patient and echovirus in the other), and in nine patients, viral antigen was detected. Acute viral infection was confirmed in 51 (24.1%) patients. Bacterial pneumonia was diagnosed in 84 (39.8%) patients, 23 of whom had concurrent viral infection. Acute viral pneumonia without any other identified pathogen was diagnosed in 28 patients. Streptococcus pneumoniae and Chlamydia pneumoniae were the most frequently identified microorganisms.

Azithromycin: single 1.5 g dose in the treatment of patients with atypical pneumonia syndrome--a randomized study.

Abstract: An open comparative study was undertaken in order to assess the efficacy and safety of a single dose of azithromycin in the treatment of community-acquired atypical pneumonia. A total of 100 adult patients with atypical pneumonia syndrome were randomized to receive 1.5 g of azithromycin as a single dose, or 500 mg once daily for 3 days. The presence of Mycoplasma pneumoniae, Chlamydia pneumoniae, Chlamydia psittaci, Coxiella burnetii, and Legionella pneumophila infection was diagnosed by serological tests. Control clinical examinations were performed 72 h, 10-12 days and 4 weeks after treatment initiation. Among 96 patients (48 in each group) who were evaluable for clinical efficacy M. pneumoniae infection was confirmed in 24, C. pneumoniae in nine, C. psittaci in five, C. burnetii in six, and L. pneumophila in five. Forty-seven patients (97.9%) in each group were cured. Side effects were observed in two patients in the single-dose group, and one patient in the 3-day group. In conclusion, a single 1.5 g dose of azithromycin may be an alternative to the standard 3-day azithromycin regimen in the treatment of outpatients with atypical pneumonia syndrome.

Role of polymorphonuclear neutrophils in a murine model of Chlamydia psittaci-induced abortion.

Abstract: To assess the role of polymorphonuclear neutrophils (PMNs) in Chlamydia psittaci infection in a pregnant mouse model, pregnant and nonpregnant Swiss OF1 mice were depleted of PMNs by treatment with the RB6-8C5 monoclonal antibody before intraperitoneal infection with C. psittaci serotype 1. Nondepleted mice served as infection controls. Depleted mice aborted earlier and had a much higher mortality rate than nondepleted mice. Bacteriological analysis showed that the number of chlamydiae isolated from the spleens of depleted mice at 5 and 7 days postinfection was 100 times greater than that isolated from nondepleted mice. Histopathological analysis of the placentas of depleted mice showed widespread necrosis of the uteroplacental units, with weak immunoreaction to chlamydial antigen, while the placentas of nondepleted mice showed substantial neutrophil infiltration but no large areas of necrosis, with moderate to strong immunoreaction to chlamydial antigen. The livers of depleted mice showed numerous chlamydial inclusions in the hepatocytes, delayed microgranuloma formation, and in the pregnant animals extensive coagulative periportal necrosis. The livers of nondepleted mice displayed multiple small foci of PMNs and mononuclear cells with microgranuloma formation. Among this group of mice, the pregnant animals always had more hepatic damage than nonpregnant animals. Our results suggest that PMNs play an essential role in the response to C. psittaci primary infection, preventing the uncontrolled multiplication of chlamydiae in the liver and spleen.

Comparison of the polymerase chain reaction and culture for the detection of feline Chlamydia psittaci in untreated and doxycycline-treated experimentally infected cats.

Abstract: The diagnostic sensitivity of the polymerase chain reaction (PCR) was compared with that of culture on conjunctival swabs over the course of infection in 4 doxycycline-treated and 4 untreated cats that were experimentally infected with feline Chlamydia psittaci. Treated cats were given 25 mg (5 mg/kg) of doxycycline orally twice daily for 3 weeks from day 6 after challenge. Clinical signs improved within 3 days of institution of treatment. Culture remained positive for 1 day and PCR remained positive for up to 5 days after treatment was commenced. No recurrence of clinical signs occurred and the organism could not be detected by either PCR or culture for 2 weeks after cessation of therapy. In the 4 untreated cats, conjunctival swabs were taken daily to day 14 and every 2nd weekday to day 64 after challenge. PCR was significantly more sensitive than culture in untreated cats overall (PCR 85.7%, culture 72.9%, P approximately 0) and for cats with clinical signs (PCR 89.2%, culture 79.2%, P = .008). PCR and culture had equivalent sensitivity (100%) for cats showing clinical signs in the 1st month of infection, whereas PCR was considerably more sensitive than culture for cats showing clinical signs in the 2nd month (PCR 72.9%, culture 47.9%, P = .028). Organisms were not detected by PCR in blood or any tissue collected from treated or untreated cats at postmortem. Thus, effective treatment of chlamydiosis in cats is possible with much shorter treatment regimens than currently recommended, and PCR is the more sensitive diagnostic method in chronically infected cats.

Genomic relatedness of Chlamydia isolates determined by amplified fragment length polymorphism analysis.

Abstract: Chlamydiae are obligate intracellularly growing bacteria. They are widespread throughout the world and infect both humans and animals. Currently, four species, Chlamydia pneumoniae, Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pecorum, belonging to the genus Chlamydia of the family Chlamydiaceae within the order Chlamydiales, are recognized (10, 11, 35). C. pneumoniae and C. trachomatis are primarily human pathogens. C. pneumoniae has been recognized as a major cause of respiratory infections. In addition, C. pneumoniae infection has been associated with new-onset asthma, exacerbation of chronic asthma, atherosclerotic disease, and, recently, Alzheimer’s dementia (2, 22). C. trachomatis is a major cause of sexually transmitted diseases and trachoma in humans (18). C. psittaci and C. pecorum are primarily animal pathogens, but C. psittaci may cause zoonotic infections (44). Restriction fragment length polymorphism (RFLP) analysis of PCR-amplified genes has been used to characterize chlamydial isolates. Using PCR-RFLP analysis of different genes, Chlamydia could be differentiated at the species level, and C. trachomatis and C. psittaci could be differentiated at a strain level corresponding to serovars and types (4, 12–14, 24, 29, 31, 53). However, C. pneumoniae isolates originating from all over the world could not be differentiated by this technique (4, 13, 29). Furthermore, the available sequence data for C. pneumoniae shows complete or nearly complete conservation for omp1, omp2, 16S rRNA, domain I of the 23S rRNA, RNase P RNA, the genes for the 53-kDa protein and the 76-kDa protein, dnaK, and waaA (kdtA) and the 16S-23S ribosomal DNA intergenic spacer (7, 13, 15, 17, 21, 26, 30, 39, 40, 55). By analysis of the whole genome using RFLP (1, 5, 9, 27, 28, 37, 38, 42), random amplification of polymorphic DNA (RAPD) (41, 45), or hybridization (5, 6, 9), the four species could be differentiated, and subgroups could be recognized within the C. trachomatis and C. psittaci species. These findings are in agreement with the power of discrimination of RFLP and RAPD at the species-to-strain level and of DNA-DNA hybridization at the genus-to-subspecies level (52). RFLP analysis of the genome of C. pneumoniae showed only two nearly identical patterns. One extra band was observed in two of eight C. pneumoniae isolates (5). However, DNA-DNA hybridization experiments showed 94 to 96% relatedness among C. pneumoniae isolates, suggesting at least some genomic variation (6). Recently, a novel high-resolution technique has been introduced for whole-genome analysis: amplified fragment length polymorphism (AFLP) (54). This technique requires relatively low amounts of genomic DNA. The DNA is digested by a combination of a restriction enzyme that has a high number of restriction sites in DNA and a restriction enzyme that has an average number of restriction sites in DNA. Selected sets of restriction fragments are amplified and analyzed on gels. This technique has proven its usefulness as a tool in bacterial taxonomy and epidemiology (16, 20, 43) and has also been applied in C. trachomatis research (32). Here, we report on the application of AFLP to analyze the differences among Chlamydia species and, within the species, among subgroups.

Methods of detection of Chlamydia psittaci in domesticated and wild birds.

Abstract: Objective To study the occurrence of Chlamydia psittaci in domesticated and wild birds and compare the sensitivity of molecular detection with cell culture isolation. Design Study of cell culture isolation and PCR detection of C psittaci in avian samples. Procedure Samples were obtained from 485 birds. Domesticated birds were selected at random from pet shops, private aviaries and zoos, while wild birds were captured locally, sampled, and immediately released. Swabs were collected from choanal slit, conjunctiva and cloaca of each bird and pooled. Samples were divided into equal portions for use in PCR dot-blot and cell culture detection. PCR and dot-blot detection was based on the ompB gene. Results Prevalence of infection varied markedly between flocks of captive birds. It was highest where there were frequent changes in the flock members or where there were many birds confined in small areas. C psittaci was not detected in wild birds or water birds. The sensitivity of cell culture compared to PCR dot-blot detection was 68%. All samples positive by cell culture were also positive by PCR. Conclusions PCR-dot blot detection of C psittaci in birds appears to be more sensitive than cell culture isolation in this study. C psittaci infection of birds may occur in clinically normal captive birds.

Differences in the immune response against ruminant chlamydial strains in a murine model.

Abstract: CBA/J mice were used in the present study to establish differences between the immune response to three chlamydial strains: AB7 (Chlamydia psittaci wild-type strain), 1B (C. psittaci vaccinal strain) and iB1 (C. pecorum). The evolution of chlamydial infection was evaluated in each strain by studying the clinical signs, the number of bacteria isolated from the spleen and the pathology of the liver. Three aspects of the immune response were then studied: the characterization of the infiltrate of leukocytes in the liver, the percentages of T- and B-cells, macrophages and neutrophils in the spleen, and the presence of cytokines in the serum. Infection followed a different course in the C. psittaci-infected mice; 1B-infected mice showed milder levels in all the parameters analysed than their AB7-infected counterparts. The resolution of infection was earlier in 1B-infected mice and, although the immune response to both strains was Th1-like, a more intense CD8+ T-cell response and an earlier presence of TNF-alpha in serum were observed in this group. C. pecorum infection was controlled mainly by a non-specific immune response, since these mice showed no signs of a systemic specific immune response. Neutrophil depletion experiments showed that these cells play a very limited role in the non-specific response against C. pecorum.

Expression of Chlamydia psittaci- and human immunodeficiency virus-derived antigens on the cell surface of Lactobacillus fermentum BR11 as fusions to bspA.

Abstract: The basic surface protein, BspA, has been used as a fusion partner to direct peptide antigens from the human immunodeficiency virus gp41 protein and the Chlamydia psittaci OmpA protein to the cell surface of Lactobacillus fermentum BR11. BspA has potential utility in the construction of live vaccines and diagnostic reagents.

Cytokine release by ovine macrophages following infection with Chlamydia psittaci

Abstract: Chlamydia psittaci is an obligate intracellular pathogen that causes abortion in both sheep and humans. The disease in sheep (but not humans) is characterized by a long-term persistent phase that appears to be under the control of interferon-gamma. However, nothing is known about cytokine induction that precedes the persistent phase in sheep. Primary alveolar lavage cells recovered from normal adult sheep were used to study cytokine production in the first 72 h of infection with C. psittaci. These cells were phenotypically characteristic of macrophages, being adherent, phagocytic, CD14+ and staining positive for non-specific esterase. In vitro infection of the macrophages with C. psittaci resulted in the release of IL-1beta, IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) as measured by ovine-specific ELISAs. Heat-treated chlamydiae (1 h at 65 degrees C) did not induce the release of IL-1beta, but the release of IL-8 was similar to that induced by untreated organisms. The cells from different sheep varied most notably in their patterns of GM-CSF release in response to heat-treated and untreated organisms.

Serotyping of chlamydial clinical isolates from birds with monoclonal antibodies.

Abstract: Forty-nine avian chlamydial strains, isolated mainly from various regions in France and from different species of birds, were analyzed and tested with a panel of nine monoclonal antibodies (MAbs) by the indirect microimmunofluorescence test (MIF). The MAbs included five serovar-specific MAbs, three MAbs raised against Chlamydia psittaci and Chlamydia pecorum ovine strains, and one genus-specific MAb. Of the 49 isolates, 41 came from parrots or budgerigars; the rest were from pigeons, a canary, a duck, and a dove. Two additional strains were from unknown hosts. Most of these avian strains were successfully serotyped according to their reactions with five serovar-specific MAbs by the MIF test. The serovars of 44 strains were determined: 39 were of serovar A, 3 of serovar B, and 2 of serovar E. The remaining five isolates were unclassified because they did not react with any of five serovar-specific MAbs but did react with genus MAb or the MAbs produced with ovine strains. The five unclassified isolates (two from budgerigars, two from Gabon gray parrots, and one from a duck) indicate that one or more additional serovars of C. psittaci exist in birds. The heterogeneity within each subgroup was evident because the 49 avian isolates gave 10 subgroups when the results of the five serovar-specific MAbs were combined with results from the three MAbs produced with ovine strains. This heterogeneity of the serovar isolates, as shown by the combination of MAbs, could provide strain markers very useful for epidemiologic studies.

Evaluation of the polymerase chain reaction in comparison with other diagnostic methods for the detection of Chlamydia psittaci

Abstract: Various diagnostic methods exist for the detection of Chlamydia psittaci. In the current study, the test performance of polymerase chain reaction (PCR) was compared with other testing methods used in the diagnosis of C. psittaci. Tissue and fecal specimens (n = 119) of avian and mammalian origin were tested by PCR and one or more of the following methods: cell culture, enzyme-linked immunosorbent assay, and direct fluorescein-conjugated monoclonal antibody staining. Several gold standards, based on results of testing methods other than PCR, were used to calculate the following test performance characteristics of PCR: sensitivity and specificity, with their 95% confidence intervals; kappa statistics, a measure of intertest agreement; and lambda statistics, a chance-corrected estimate of the sensitivity and specificity. Overall, the test performance characteristics of PCR were low compared with the other testing methods. Possible reasons for the poor test performance of PCR in the current study include destruction of the organisms during storage, interference with the PCR by other reagents, or technical errors.

[Chlamydia abortion in sheep: possibilities for serological diagnosis using a competitive ELISA and insight into the epidemiologic situation in Switzerland].

Abstract: 466 sheep sera out of 19 flocks in Switzerland were examined by a competitive enzyme linked immunosorbent assay (cELISA) for antibodies against Chlamydia psittaci "serotype 1" ("ovine enzootic abortion"). Since numerous positive reactors were found in flocks without abortion history, 30 fecal samples out of two of these flocks were examined by PCR for evidence of chlamydial DNA. One of these samples turned out to contain DNA of Chlamydia psittaci "serotype 1". These results suggest, that in Switzerland "serotype 1" of Chlamydia psittaci is widespread not only as cause of chlamydial abortion but also as latent intestinal infection in sheep. The resulting difficulties for serological diagnosis of chlamydial abortion and possible solutions based on the cELISA are discussed. The complement fixation test (CFT), still considered as standard method for serological examination for Chlamydiae, has additionally been applied.

Review of techniques for the diagnosis of Chlamydia psittaci infection in psittacine birds.

Abstract: Avian chlamydiosis in psittacine birds is characterized by clinical signs such as anorexia, depression, respiratory distress, or diarrhea. The disease is caused by widespread infection of mononuclear phagocytes by the obligate intracellular bacterium, Chlamydia psittaci. Chlamydial organism can be transmitted to humans via dried feces and nasal discharge, causing the clinical disease of psittacosis. Clinical signs of psittacosis include influenza-like symptoms, and infection can lead to severe pneumonia or other nonrespiratory ailments. 2 Because of the zoonotic potential of C. psittaci ,i t is important to make a rapid, definitive diagnosis in affected birds. Diagnosis of chlamydiosis can be problematic. Isolation and identification is the gold standard for most infectious diseases, but these techniques may be difficult to use for chlamydiosis. 3,7 First, many birds can be carriers and may harbor subclinical infections. Second, culturing requires the use of specialized cell lines or embryonated eggs and inoculation techniques that are not available in all laboratories. 3,7 Third, because chlamydial organisms are shed intermittently in the feces, a single culture can lead to a false-negative result. 7 There are a variety of serologic tests available for diagnosis of chlamydiosis. Unfortunately, serologic responses in infection and disease vary widely in psittacine birds, and early stages of infection can have negative results. 7 Attempts at direct identification using fluorescent antibody testing on fresh tissue or characteristic inclusions seen histopathologically with hematoxylin and eosin (HE), Giemsa, or Gimenez staining have become more widely used. 3,6 Fluorescent antibody testing, although reliable, requires the submission of fresh tissue, and often specimens are submitted to the diagnostic laboratory already in formalin. Diagnosis in formalin-fixed, paraffin-embedded (FFPE) tissues relies on the visual methods of finding organisms morphologically compatible with C. psittaci with HE or histochemical stains. Often this option is the only one available in a diagnostic laboratory setting, and it is fraught with potentials for falsenegative or false-positive interpretations based on insufficient or spurious histochemical reactions. Immunohistochemistry (IHC) can help provide positive identification of a specific antigen within FFPE tissue. The aim of this study was to examine the usefulness of IHC and to compare this method with other methods based on pathology for detection of C. psittaci in FFPE tissues. Thirteen cases of chlamydiosis in psittacine birds were selected from the biopsy and necropsy archives of the Department of Pathology and the Athens Diagnostic Laboratory

Encephalitis related to Chlamydia psittaci infection in a 14-week-old calf.

Abstract: References BRAUN, U. (1990) Ultrasonographic examination of the liver in cows. American Journal of Veterinary Research 51, 1522-1526 BRAUN, U. (1997a) Leber. In Atlas und Lehurbuch der Ultraschalldiagnostik beim Rind. Ed U. Braun. Berlin, Parey Buchverlag. pp 35-67 BRAUN, U. (1997b) Abdomen, Bauchdecke. In Atlas und Lehurbuch der Ultraschalldiagnostik beim Rind. Ed U. Braun. Berlin, Parey Buchverlag. pp 177-206 BRAUN, U. & GERBER, D. (1992) Percutaneous ultrasound-guided cholecystocentesis in cows. American Journal of Veterinary Research 53, 1079-1084 BRAUN, U. & GERBER, D. (1994) Influence of age, breed, and stage of pregnancy on hepatic ultrasonographic findings in cows. American Journal of Veterinary Research 55, 1201-1205 BRAUN, U. & GOTZ, M. (1994) Ultrasonography of the reticulum in cows. American Journal of Veterinary Research 55, 325-332 BRAUN, U., HERMANN, M. & PABST, B. (1989) Haematological and biochemical findings in cattle with dilatation and torsion of the caecum. Veterinary Record 125, 396-398 CRAIG, A. M., PEARSON, E. G., MEYER, C. & SCHMITZ, J. A. (1991) Serum liver enzyme and histopathologic changes in calves with chronic and chronicdelayed Senecio jacobaea toxicosis. American Journal of Veterinary Research 52, 1969-1978 DE BARROS, C. S. L., CASTILHOS, L. M. & DOS SANTOS, M. N. (1987) Liver biopsy in ragwort poisoning. Veterinary Record 121, 382 DE BARROS, C. S. L., DRIEMEIER, D., PILATI, C., BARROS, S. S. & CASTILHOS, L. M. L. (1992) Senecio spp poisoning in cattle in southern Brazil. Veterinary & Human Toxicology 34, 241-246 GERBER, D. (1993) Sonographische Befunde an der Leber des Rindes. DrMedVet Thesis, University of Zurich KELLY,W. R. (1993) Pyrrolizidine alkaloids. In Pathology ofDomestic Animals, Vol 2, 4th edn. Eds K. V. F. Jubb, P. C. Kennedy, N. Palmer. San Diego, Academic Press. pp 392-395 KREMER, H., DOBRINSKI, W. &SCHREIBER, M. A. (1994) Leber. In Sonographische Diagnostik. Innere Medizin und angrenzende Gebeite. Eds H. Kremer, W. Dobrinski. 4th edn. Munchen, Wien, Baltimore, Urban & Schwarzenberg. pp 63-88 MENDEZ, M. C. & RIET-CORREA, F. (1993) Intoxication by Senecio tweediei in cattle in southern Brazil. Veterinary & Human Toxicology 35, 55 MOLYNEUX, R. J., JOHNSON, A. E., OLSEN, J. D. & BAKER, D. C. (1991) Toxicity of pyrrolizidine alkaloids from Riddell groundsel (Senecio riddellii) to cattle. American Journal ofVeterinary Research 52, 146-151 MONAGHAN, M. L. & SHEAHAN, B. J. (1987) Liver biopsy in ragwort poisoning. Veterinary Record 120, 374 NOBLE, J. W., CROSSLEY, J., HILL, B. D., PIERCE, R. J., McKENZIE, R. A., DEBRITZ, M. & MORLEY, A. A. (1994) Pyrrolizidine alkaloidosis of cattle associated with Senecio lautus. Australian Veterinary Journal 71, 196-200 ODRIOZOLA, E., CAMPERO, C., CASARO, A., LOPEZ, T., OLIVIERI, G. & MELUCCI, 0. (1994) Pyrrolizidine alkaloidosis in Argentinian cattle caused by Senecio selloi. Veterinary & Human Toxicology 36, 205-208 POHLENZ, J., LOTHI, J., MINDER, H. P. & BIVETTI, A. (1980) Enzootische Leberzirrhose beim Rind, verursacht durch Pyrrolizidinalkaloide nach Aufnahme von Senecio alpinus (Alpenkreuzkraut). Schweizer Archiv fur Tierheilkunde 122, 183-193 RADOSTITS, 0. M., BLOOD, D. C. & GAY, C. C. (1994a) Photosensitization. In Veterinary Medicine. A Textbook of the Diseases of Cattle, Sheep, Pigs, Goats & Horses. 8th edn. London, Bailliere Tindall. pp 546-548 RADOSTITS, 0. M., BLOOD, D. C. & GAY, C. C. (1994b) Pyrrozilidine alkaloid poisoning. In Veterinary Medicine. A Textbook ofthe Diseases of Cattle, Sheep, Pigs, Goats & Horses. 8th edn. London, BailliWre Tindall. pp 1563-1566 ROSENBERGER, G. & GRONDER, H. D. (1970) Gelbsucht (Ikterus). In Krankheiten des Rindes. Ed G. Rosenberger. Berlin, Hamburg, Paul Parey. pp 363-364 SMITH, R. A. & PANARITI, E. (1995) Intoxication of Albanian cattle after ingestion of Senecio subalpinus. Veterinary & Human Toxicology 37,478-479 STOBER, M. (1970a) Jakobskraut und Kreuzkraut (Senecio jacobaea, S vulgaris). In Krankheiten des Rindes. Ed G. Rosenberger. Berlin, Hamburg, Paul Parey. pp 1282-1283 STOBER, M. (1970b) Photosensibilitatsreaktionen (Dermatitis solaris, 'Sonnenbrand'). In Krankheiten des Rindes. Ed G. Rosenberger. Berlin, Hamburg, Paul Parey. pp 1323-1324

Fulminant psittacosis requiring mechanical ventilation and demonstrating serological cross-reactivity between Legionella longbeachae and Chlamydia psittaci

Abstract: Chlamydia psittaci infection typically causes a mild respiratory illness in humans. Severe respiratory failure requiring mechanical ventilation or intensive care therapy is an uncommon development. The aetiological agents causing severe community acquired pneumonia often remain undetermined. Serological tests may aid in diagnosis. We present two cases of fulminant psittacosis, one demonstrating early cross-reactivity with Legionella longbeachae.

Serology for Chlamydia pneumoniae (TWAR)

Abstract: As many other medical sciences, serology for Chlamydia pneumoniae (TWAR) has been improved according to our demand to cope with the progress of the knowledge on the organisms.

Significance of host cell kinesin in the development of Chlamydia psittaci.

Abstract: The influence of the microtubule-associated motor protein kinesin on Chlamydia psittaci inclusion development in epithelial and fibroblast cell lines was addressed. Kinesin was blocked early after chlamydial internalization (4 h postinfection [p.i.]) and before the initiation of active chlamydial multiplication (8 h p.i.). Chlamydia development was monitored by fluorescence and transmission electron microscopy at different times during the cycle. In both host cell lines, kinesin blockage restricted mitochondria from the chlamydial vacuole. The effects of kinesin blockage on the C. psittaci replication cycle included the presence of multiple inclusions up to late in the cycle, the presence of enlarged pleomorphic reticulate bodies, and a delayed reappearance of elementary bodies. The last effect seems to be greater when kinesin is blocked early after infection. Our results show that kinesin activity is required for optimal development of these microorganisms, most probably acting through the apposition of mitochondria to the C. psittaci inclusions.

Role of 'atypical' pneumonia pathogens in respiratory tract infections.

Abstract: The 'atypical' pathogens are important causes of pneumonia, causing illness ranging from mild to life-threatening. The most common atypical pathogens are Mycoplasma pneumoniae and Chlamydia pneumoniae; others include Legionella species, Chlamydia psittaci and viruses such as influenza, adenovirus and respiratory syncytial virus. Infection rates for these agents are difficult to determine because many clinicians and investigators do not routinely test for them, but reported rates are in the range of up to 8% (for C pneumoniae) and 15% to 20% (M pneumoniae) of all cases of pneumonia. Diagnostic testing is very difficult because most of these agents cannot be easily cultured. Diagnosis relies on either high acute antibody titres (quickly available but not very accurate) or paired serology samples (more accurate but requires at least a week). While rapid identification using automated polymerase chain reaction testing may be possible in the future, current management is based largely on empirical treatment.