| obligate intracellular bacterial parasites of acanthamoebae related to chlamydia spp. | the phylogeny of obligate intracellular coccoid parasites of acanthamoebae isolated from the nasal mucosa of humans was analyzed by the rrna approach. the primary structures of the 16s and 23s rrna molecules of one strain were determined in almost full length. in situ hybridization with a horseradish peroxidase-labeled oligonucleotide probe targeted to a unique signature site undoubtedly correlated the retrieved 16s rrna sequence to the respective intracellular parasite. this probe also hybridiz ... | 1997 | 8979345 |
| molecular evidence for the existence of additional members of the order chlamydiales. | respiratory tract infections in man may be caused by several members of the genus chlamydia and also by two chlamydia-like strains, 'simkania negevensis' (z-agent) and 'parachlamydia acanthamoebae' (bng). to facilitate diagnostic procedures a pcr assay able to detect all known chlamydiaceae sequences in one reaction was developed. for this purpose, primers were selected to amplify a fragment of the 16s rrna gene. characterization of the amplified fragments was done by hybridization with specific ... | 1999 | 10075423 |
| 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. | 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 ... | 1999 | 10319462 |
| an unspliced group i intron in 23s rrna links chlamydiales, chloroplasts, and mitochondria. | chlamydia was the only genus in the order chlamydiales until the recent characterization of simkania negevensis z(t) and parachlamydia acanthamoebae strains. the present study of chlamydiales 23s ribosomal dna (rdna) focuses on a naturally occurring group i intron in the i-cpai target site of 23s rdna from s. negevensis. the intron, snlsu. 1, belonged to the ib4 structural subgroup and was most closely related to large ribosomal subunit introns that express single-motif, laglidadg endonucleases ... | 1999 | 10438738 |
| characterization of the rnpb gene and rnase p rna in the order chlamydiales. | the sequence of the rnase p rna gene (rnpb) was determined for 60 strains representing all nine species in the family chlamydiaceae and for the related chlamydiales species, parachlamydia acanthamoebae and simkania negevensis. these sequences were used to infer evolutionary relationships among the chlamydiaceae. the analysis separated chlamydophila and chlamydia into two lineages, with chlamydophila forming three distinct clusters: the chlamydophila pneumoniae strains; the chlamydophila pecorum ... | 2000 | 10826799 |
| phylogenetic diversity among geographically dispersed chlamydiales endosymbionts recovered from clinical and environmental isolates of acanthamoeba spp. | the recently proposed reorganization of the order chlamydiales and description of new taxa are broadening our perception of this once narrowly defined taxon. we have recovered four strains of gram-negative cocci endosymbiotic in acanthamoeba spp., representing 5% of the acanthamoeba sp. isolates examined, which displayed developmental life cycles typical of members of the chlamydiales. one of these endosymbiont strains was found stably infecting an amoebic isolate recovered from a case of amoebi ... | 2000 | 10831445 |
| evidence for additional genus-level diversity of chlamydiales in the environment. | the medically important order chlamydiales has long been considered to contain a few closely related bacteria which occur exclusively in animals and humans. this perception of diversity and habitat had to be revised with the recent identification of the genera simkania, waddlia, parachlamydia, and neochlamydia with the latter two comprising endosymbionts of amoebae. application of a newly developed pcr assay for the specific amplification of a near full length 16s rdna fragment of these novel ch ... | 2001 | 11682181 |
| legionella-like and other amoebal pathogens as agents of community-acquired pneumonia. | we tested serum specimens from three groups of patients with pneumonia by indirect immunofluorescence against legionella-like amoebal pathogens (llaps) 1-7, 9, 10, 12, 13; parachlamydia acanthamoeba strains bn 9 and hall's coccus; and afipia felis. we found that llaps play a role (albeit an infrequent one) in community-acquired pneumonia, usually as a co-pathogen but sometimes as the sole identified pathogen. | 2001 | 11747734 |
| parachlamydiaceae: potential emerging pathogens. | parachlamydiaceae, which naturally infect amoebae, form a sister taxon to the chlamydiaceae on the basis of the chlamydia-like cycle of replication and 80% to 90% homology of ribosomal rna genes. because intra-amoebal growth could increase the virulence of some intracellular bacteria, parachlamydiaceae may be pathogenic. arguments supporting a pathogenic role are that chlamydia pneumoniae, a well-recognized agent of pneumonia, was shown to infect free-living amoebae and that another member of th ... | 2002 | 12023921 |
| crescent bodies of parachlamydia acanthamoeba and its life cycle within acanthamoeba polyphaga: an electron micrograph study. | parachlamydiaceae are endosymbionts of free-living amoeba first identified in 1997. two developmental stages, elementary and reticulate bodies, were observed; however, their localization and proportions according to culture condition and duration remain unknown. the life cycle of parachlamydia acanthamoeba within acanthamoeba polyphaga was studied by transmission electron microscopy of 8-, 36-, and 144-h coculture. morphometry and quantification were performed using samba software. the elementar ... | 2002 | 12039769 |
| detection and differentiation of chlamydiae by fluorescence in situ hybridization. | chlamydiae are important pathogens of humans and animals but diagnosis of chlamydial infections is still hampered by inadequate detection methods. fluorescence in situ hybridization (fish) using rrna-targeted oligonucleotide probes is widely used for the investigation of uncultured bacteria in complex microbial communities and has recently also been shown to be a valuable tool for the rapid detection of various bacterial pathogens in clinical specimens. here we report on the development and eval ... | 2002 | 12147510 |
| antibiotic susceptibilities of parachlamydia acanthamoeba in amoebae. | parachlamydia acanthamoeba are intracellular bacteria of amoebae and are considered potential etiological agents of human pneumonia. we have determined the in vitro antibiotic susceptibilities of two strains (strain bn(9) and hall's coccus) in acanthamoeba polyphaga. the two strains were susceptible to tetracyclines, macrolides, and rifampin, but resistant to fluoroquinolones. | 2002 | 12183273 |
| new parachlamydial 16s rdna phylotypes detected in human clinical samples. | chlamydiales are important intracellular bacterial pathogens, causing a wide variety of diseases in vertebrates, including humans. besides the well-known species in the family chlamydiaceae, new chlamydial organisms have recently been discovered, forming three new families: parachlamydiaceae, simkaniaceae and waddliaceae. parachlamydia acanthamoebae and simkania negevensis are currently investigated as emerging human respiratory pathogens. additional chlamydial lineages have been discovered by 1 ... | 2002 | 12455703 |
| increasing diversity within chlamydiae. | in recent years, 16s ribosomal dna analyses has allowed the recognition of new chlamydia organisms, requiring the creation of new species, genera, and families within this unique, deep lineage of prokaryotes. the trachoma and psittaci groups chlamydiae are now recognized as separate genera, chlamydia and chlamydophila, respectively, and biovars of each group have been elevated to the species rank. simkania and parachlamydia have been associated with human respiratory infections, while waddlia se ... | 2003 | 12638718 |
| serological hint suggesting that parachlamydiaceae are agents of pneumonia in polytraumatized intensive care patients. | parachlamydiaceae are potential emerging pathogens that naturally infect free-living amoebae. intensive-care patients are highly exposed to aerosols and, consequently, exposed to free-living amoebae and to their intracellular hosts. thus, we tested intensive-care patients for antibodies to parachlamydia and determined if serum reactivity was associated with pneumonia. patients who underwent intubation and were hospitalized in our intensive-care unit were eligible. clinical data and serum were re ... | 2003 | 12860644 |
| parachlamydia acanthamoeba is endosymbiotic or lytic for acanthamoeba polyphaga depending on the incubation temperature. | parachlamydiaceae are potential emerging pathogens that naturally infect free-living amoebae. we investigated the affects of incubation temperature on the growth and cytopathic effect of p. acanthamoeba in acanthamoeba polyphaga. a. polyphaga were infected with p. acanthamoeba and incubated at different temperatures for ten days. bacterial growth was quantified by real-time pcr. cytopathic effects were determined by counting the number of cysts and viable amoebae (unstained with trypan blue) in ... | 2003 | 12860700 |
| history of the adp/atp-translocase-encoding gene, a parasitism gene transferred from a chlamydiales ancestor to plants 1 billion years ago. | nonmitochondrial adp/atp translocase is an energy parasite enzyme. its encoding gene, tlc, is found only in rickettsiales, chlamydiales, and plant and alga plastids. we demonstrate the presence of tlc in parachlamydia acanthamoebae. this gene shares more similarity with the tlc1 gene of chlamydiaceae and the tlc of plant and alga plastids than with the tlc2 gene of chlamydiaceae. phylogenetic analysis, including all other tlc homologs found in genbank, showed that tlc was duplicated in a chlamyd ... | 2003 | 12957942 |
| parachlamydia acanthamoebae enters and multiplies within human macrophages and induces their apoptosis [corrected]. | parachlamydia acanthamoebae is an obligately intracellular bacterium that naturally infects free-living amoebae. it is a potential human pathogen and may survive in human macrophages. we studied p. acanthamoebae entry into, and multiplication within, human monocyte-derived macrophages. after 8 h of incubation, 80% of macrophages were infected with a mean of 3.8 p. acanthamoebae organisms per cell. electron microscopy demonstrated that parachlamydiae were in an intracellular vacuole. after infect ... | 2003 | 14500518 |
| atp/adp translocases: a common feature of obligate intracellular amoebal symbionts related to chlamydiae and rickettsiae. | atp/adp translocases catalyze the highly specific transport of atp across a membrane in an exchange mode with adp. such unique transport proteins are employed by plant plastids and have among the prokaryotes so far only been identified in few obligate intracellular bacteria belonging to the chlamydiales and the rickettsiales. in this study, 12 phylogenetically diverse bacterial endosymbionts of free-living amoebae and paramecia were screened for the presence of genes encoding atp/adp transport p ... | 2004 | 14729693 |
| microorganisms resistant to free-living amoebae. | free-living amoebae feed on bacteria, fungi, and algae. however, some microorganisms have evolved to become resistant to these protists. these amoeba-resistant microorganisms include established pathogens, such as cryptococcus neoformans, legionella spp., chlamydophila pneumoniae, mycobacterium avium, listeria monocytogenes, pseudomonas aeruginosa, and francisella tularensis, and emerging pathogens, such as bosea spp., simkania negevensis, parachlamydia acanthamoebae, and legionella-like amoebal ... | 2004 | 15084508 |
| detection of mycobacteria and chlamydiae in granulomatous inflammation of reptiles: a retrospective study. | a retrospective study on reptile tissues presenting with granulomatous inflammation was performed to detect the possible presence of mycobacteria and chlamydiae in these lesions. ninety cases including 48 snakes, 27 chelonians, and 15 lizards were selected. mycobacteria were detected by ziehl-neelsen (zn) staining and a broad-range polymerase chain reaction (pcr) followed by dna sequencing. to detect chlamydiae, immunohistochemistry with monoclonal antibodies against chlamydial lipopolysaccharid ... | 2004 | 15232139 |
| emerging chlamydial infections. | chlamydiae are important intracellular bacterial pathogens of vertebrates. in the last years, novel members of this group have been discovered: parachlamydia acanthamoebae and simkania negevensis seems to be emerging respiratory human pathogens, while waddlia chondrophila might be a new agent of bovine abortion. various species have been showed to infect also the herpetofauna and fishes, and some novel chlamydiae are endosymbionts of arthropods. in addition, molecular studies evidenced a huge di ... | 2004 | 15239381 |
| a genomic island present along the bacterial chromosome of the parachlamydiaceae uwe25, an obligate amoebal endosymbiont, encodes a potentially functional f-like conjugative dna transfer system. | the genome of protochlamydia amoebophila uwe25, a parachlamydia-related endosymbiont of free-living amoebae, was recently published, providing the opportunity to search for genomic islands (gis). | 2004 | 15615594 |
| [the discovery of naked cluster particles of parachlamydia and its developmental mechanism]. | to study the survival and developmental morphology of parachlamydia (bn9) within acanthamoeba. | 2004 | 15631746 |
| recovery of an environmental chlamydia strain from activated sludge by co-cultivation with acanthamoeba sp. | chlamydiae are a unique group of obligate intracellular bacteria comprising important pathogens of vertebrates as well as symbionts of free-living amoebae. although there is ample molecular evidence for a huge diversity and wide distribution of chlamydiae in nature, environmental chlamydiae are currently represented by only few isolates. this paper reports the recovery of a novel environmental chlamydia strain from activated sludge by co-cultivation with acanthamoeba sp. the recovered environmen ... | 2005 | 15632447 |
| intracellular trafficking of parachlamydia acanthamoebae. | parachlamydia acanthamoebae is an obligate intracellular bacterium that naturally infects free-living amoebae. it is a potential agent of pneumonia that resists destruction by human macrophages. however, the strategy used by this chlamydia-like organism in order to resist to macrophage destruction is unknown. we analysed the intracellular trafficking of p. acanthamoebae within monocyte-derived macrophages. infected cells were immunolabelled for the bacteria and for various intracellular compartm ... | 2005 | 15760458 |
| lack of microbicidal response in human macrophages infected with parachlamydia acanthamoebae. | parachlamydia acanthamoebae is an obligate intracellular bacterium naturally infecting free-living amoebae. this potential agent of pneumonia resists destruction by human macrophages, inducing their death by apoptosis. however, the strategy used by parachlamydia to escape the microbicidal effectors of macrophages remains unknown. in this work, we defined the effect of parachlamydia on the cytokine secretion (measured in culture supernatants by immunoassays), on the oxidative burst (measured usin ... | 2005 | 15826869 |
| the lpb1 gene is important for acclimation of chlamydomonas reinhardtii to phosphorus and sulfur deprivation. | organisms exhibit a diverse set of responses when exposed to low-phosphate conditions. some of these responses are specific for phosphorus limitation, including responses that enable cells to efficiently scavenge phosphate from internal and external stores via the production of high-affinity phosphate transporters and the synthesis of intracellular and extracellular phosphatases. other responses are general and occur under a number of different environmental stresses, helping coordinate cellular ... | 2005 | 15849300 |
| conserved indels in essential proteins that are distinctive characteristics of chlamydiales and provide novel means for their identification. | all known chlamydiae are either proven human or animal pathogens or possess such potential. due to increasing reports of chlamydiae diversity in the environment, it is important to develop reliable means for identifying and characterizing chlamydiales species. the identification of environmental chlamydiae at present relies on their branching pattern in 16s rrna trees, as well as 16s/23s consensus motifs which display variability. at present, no reliable molecular signatures are known which are ... | 2005 | 16079343 |
| [the pathogenicity of amoebae-resisting chlamydiales]. | during the last 15 years, several new bacterial species related to chlamydia have been discovered within amoebae. their ability to grow within these professionnal phagocytes suggests that they are also resistant to destruction by other phagocytic cells such as alveolar macrophages and that they may be excellent candidates as new agents of pneumonia. there are growing evidence that these chlamydia-like organisms play a role as etiological agent of lower respiratory tract infections. thus, parachl ... | 2005 | 16152882 |
| 'candidatus protochlamydia amoebophila', an endosymbiont of acanthamoeba spp. | the obligately intracellular coccoid bacterium uwe25, a symbiont of acanthamoeba spp., was previously identified as being related to chlamydiae based upon the presence of a chlamydia-like developmental cycle and its 16s rrna gene sequence. analysis of its complete genome sequence demonstrated that uwe25 shows many characteristic features of chlamydiae, including dependency on host-derived metabolites, composition of the cell envelope and the ability to thrive as an energy parasite within the cel ... | 2005 | 16166679 |
| for better or worse: genomic consequences of intracellular mutualism and parasitism. | bacteria that replicate within eukaryotic host cells include a variety of pathogenic and mutualistic species. early genome data for these intracellular associates suggested they experience continual gene loss, little if any gene acquisition, and minimal recombination in small, isolated populations. this view of reductive evolution is itself evolving as new genome sequences clarify mechanisms and outcomes of diverse intracellular associations. recently sequenced genomes have confirmed a trajector ... | 2005 | 16230003 |
| ameba-associated microorganisms and diagnosis of nosocomial pneumonia. | to elucidate the role of ameba-associated microorganisms (aams) as etiologic agents of pneumonia, we screened for legionella spp., parachlamydia acanthamoeba, afipia sp., bosea spp., bradyrhizobium spp., mesorhizobium amorphae, rasbo bacterium, azorhizobium caulinodans, acanthamoeba polyphaga mimivirus, and conventional microorganisms in 210 pneumonia patients in intensive-care units by using culture, polymerase chain reaction, and serologic testing. these resulted in 59 diagnoses in 40 patients ... | 2006 | 16494750 |
| pathogenic potential of novel chlamydiae and diagnostic approaches to infections due to these obligate intracellular bacteria. | novel chlamydiae are newly recognized members of the phylum chlamydiales that are only distantly related to the classic chlamydiaceae, i.e., chlamydia and chlamydophila species. they also exhibit an obligate biphasic intracellular life cycle within eukaryote host cells. some of these new chlamydiae are currently considered potential emerging human and/or animal pathogens. parachlamydia acanthamoebae and simkania negevensis are both emerging respiratory human pathogens, waddlia chondrophila could ... | 2006 | 16614250 |
| chlamydiales in guinea-pigs and their zoonotic potential. | the aim was to detect and characterize chlamydial infections in guinea-pigs (gp) with ocular disease, study their pathogenicity and zoonotic potential and to test for the presence of acanthamoebae spp. in gp eyes and to investigate whether they could act as vectors for chlamydia-like organisms. overall 126 gp, of which 77 were symptomatic, were screened by clinical examination, cytology, gross pathology, histology, immunohistochemistry, polymerase chain reaction (pcr) and bacteriology. a new chl ... | 2006 | 16629952 |
| parachlamydia acanthamoebae enters and multiplies within pneumocytes and lung fibroblasts. | parachlamydia acanthamoebae is a chlamydia-like organism that naturally infects free-living amoebae. p. acanthamoebae is a putative emerging agent of community-acquired and inhalation pneumonia that may enter and multiply within human macrophages. however, since parachlamydia induces their apoptosis, macrophages may not represent a perennial niche for this obligate intracellular bacterium. therefore, we investigated whether pneumocytes and lung fibroblasts are permissive to parachlamydia infecti ... | 2006 | 16697235 |
| resistance of different chlamydia-like organisms to quinolones and mutations in the quinoline resistance-determining region of the dna gyrase a- and topoisomerase-encoding genes. | parachlamydia acanthamoebae has been shown to be resistant to fluoroquinolones. in this study, we determined the susceptibility of neochlamydia hartmannellae and simkania negevensis to quinolones using amoebal co-culture in the presence of serial dilutions of ciprofloxacin. the gyra and parc quinoline resistance-determining regions (qrdrs) were amplified and sequenced, and amino acid substitutions that may explain the observed quinolone resistance were investigated. neochlamydia and simkania wer ... | 2006 | 16697560 |
| criblamydia sequanensis, a new intracellular chlamydiales isolated from seine river water using amoebal co-culture. | accumulating evidence supports a role for chlamydia-related organisms as emerging pathogens for human and animals. assessment of their pathogenicity requires strain availability, at least for animal models and serological studies. as these obligate intracellular species are able to grow inside amoebae, we used co-culture with acanthamoeba castellanii in an attempt to recover new chlamydia-related species from river water. we isolated two strains from eight water samples. the first strain is a ne ... | 2006 | 17107554 |
| an acanthamoeba sp. containing two phylogenetically different bacterial endosymbionts. | acanthamoebae are ubiquitous free-living amoebae and important predators of microbial communities. they frequently contain obligate intracellular bacterial symbionts, which show a worldwide distribution. all acanthamoeba spp. described so far harboured no or only a single specific endosymbiont phylotype, and in some cases evidence for coevolution between the symbiotic bacteria and the amoeba host has been reported. in this study we have isolated and characterized an acanthamoeba sp. (strain oew1 ... | 2007 | 17504498 |
| emerging role of chlamydia and chlamydia-like organisms in adverse pregnancy outcomes. | this review considers the roles of chlamydia spp. and newly identified chlamydia-like organisms in miscarriage, stillbirths and preterm labour in both animals and humans. | 2008 | 18192789 |
| new diagnostic real-time pcr for specific detection of parachlamydia acanthamoebae dna in clinical samples. | given the low sensitivity of amoebal coculture, we developed a specific real-time pcr for the detection of parachlamydia. the analytical sensitivity was high, and the inter- and intrarun variabilities were low. when the pcr was applied to nasopharyngeal aspirates, it was positive for six patients with bronchiolitis. future studies should assess the role of parachlamydia in bronchiolitis. | 2008 | 18234873 |
| parachlamydia spp. and related chlamydia-like organisms and bovine abortion. | chlamydophila abortus and waddlia chondrophila cause abortion in ruminants. we investigated the role of parachlamydia acanthamoebae in bovine abortion. results of immunohistochemical analyses were positive in 30 (70%) of 43 placentas from which chlamydia-like dna was amplified, which supports the role of parachlamydia spp. in bovine abortion. | 2007 | 18258043 |
| predator or prey? chlamydophila abortus infections of a free-living amoebae, acanthamoeba castellani 9gu. | limited evidence exists to suggest that the ability to invade and escape protozoan host cell bactericidal activity extends to members of the chlamydiaceae, intracellular pathogens of humans and animals and evolutionary descendants of amoeba-resisting chlamydia-like organisms. pcr and microscopic analyses of chlamydophila abortus infections of acanthamoeba castellani revealed uptake of this chlamydial pathogen but, unlike the well-described inhabitant of a. castellani, parachlamydia acanthamoebae ... | 2008 | 18467146 |
| murine model of pneumonia caused by parachlamydia acanthamoebae. | the role of parachlamydia acanthamoebae as an agent of pneumonia is suggested by sero-epidemiological studies, molecular surveys and by the permissivity of macrophages, lung fibroblasts and pneumocytes to this obligate intracellular bacteria. we thus developed a murine model of pneumonia due to parachlamydia. mice were inoculated intratracheally with parachlamydia acanthamoebae. pneumonia-associated mortality was of 50% 5 days post-inoculation. lungs histopathology was characterized by purulent ... | 2008 | 18502092 |
| molecular detection of parachlamydia-like organisms in cerebrospinal fluid of patients with multiple sclerosis. | the presence of chlamydia-like organism dna was investigated by polymerase chain reaction (pcr) in cerebrospinal fluid (csf) samples from 27 patients previously found positive for chlamydia pneumoniae dna: 12 with multiple sclerosis (ms), grouped according to clinical and magnetic resonance imaging (mri) evidence of disease activity, 8 with other inflammatory neurological disorders and 7 with non-inflammatory neurological disorders. pcr evidence of chlamydia-like organisms in csf was observed on ... | 2008 | 18562511 |
| biodiversity of amoebae and amoebae-resisting bacteria in a drinking water treatment plant. | the complex ecology of free-living amoebae (fla) and their role in spreading pathogenic microorganisms through water systems have recently raised considerable interest. in this study, we investigated the presence of fla and amoebae-resisting bacteria (arb) at various stages of a drinking water plant fed with river water. we isolated various amoebal species from the river and from several points within the plant, mostly at early steps of water treatment. echinamoeba- and hartmannella-related amoe ... | 2008 | 18637950 |
| novel parachlamydia acanthamoebae quantification method based on coculture with amoebae. | parachlamydia acanthamoebae, belonging to the order chlamydiales, is an obligately intracellular bacterium that infects free-living amoebae and is a potential human pathogen. however, no method exists to accurately quantify viable bacterial numbers. we present a novel quantification method for p. acanthamoebae based on coculture with amoebae. p. acanthamoebae was cultured either with acanthamoeba spp. or with mammalian epithelial hep-2 or vero cells. the infection rate of p. acanthamoebae (amoeb ... | 2008 | 18757579 |
| evidence for parachlamydia in bovine abortion. | bovine abortion of unknown infectious aetiology still remains a major economic problem. in this study, we focused on a new possible abortigenic agent called parachlamydia acanthamoebae. retrospective samples (n=235) taken from late-term abortions in cattle were investigated by real-time diagnostic pcr for chlamydiaceae and parachlamydia spp., respectively. histological sections of cases positive by real-time pcr for any chlamydia-related agent were further examined by immunohistochemistry using ... | 2009 | 18951734 |
| no association between parachlamydia infection and atherosclerosis. | since recent studies suggested a role for parachlamydia in atherosclerosis, we investigated 354 patients with or without atherosclerosis for parachlamydia infection. six patients exhibited anti-parachlamydia igg. no patient presented igm. parachlamydial dna was not amplified from peripheral blood mononuclear cells. there was no association between atherosclerosis and parachlamydia infection. | 2009 | 19040661 |
| parachlamydia acanthamoebae infection and abortion in small ruminants. | | 2008 | 19046541 |
| evidence of maternal-fetal transmission of parachlamydia acanthamoebae. | | 2009 | 19116071 |
| parachlamydia acanthamoebae, an emerging agent of pneumonia. | parachlamydia acanthamoebae is a chlamydia-like organism that easily grows within acanthamoeba spp. thus, it probably uses these widespread free-living amoebae as a replicative niche, a cosmopolite aquatic reservoir and a vector. a potential role of p. acanthamoebae as an agent of lower respiratory tract infection was initially suggested by its isolation within an acanthamoeba sp. recovered from the water of a humidifier during the investigation of an outbreak of fever. additional serological an ... | 2009 | 19220336 |
| development of a real-time pcr for the specific detection of waddlia chondrophila in clinical samples. | waddlia chondrophila is considered as an emerging human pathogen likely involved in miscarriage and lower respiratory tract infections. given the low sensitivity of cell culture to recover such an obligate intracellular bacteria, molecular-based diagnostic approaches are warranted. we thus developed a real-time pcr that amplifies waddlia chondrophila dna. specific primers and probe were selected to target the 16s rrna gene. the pcr specifically amplified w. chondrophila but did not amplify other ... | 2009 | 19727868 |
| parachlamydia and rhabdochlamydia in premature neonates. | | 2009 | 19961711 |
| high throughput sequencing and proteomics to identify immunogenic proteins of a new pathogen: the dirty genome approach. | with the availability of new generation sequencing technologies, bacterial genome projects have undergone a major boost. still, chromosome completion needs a costly and time-consuming gap closure, especially when containing highly repetitive elements. however, incomplete genome data may be sufficiently informative to derive the pursued information. for emerging pathogens, i.e. newly identified pathogens, lack of release of genome data during gap closure stage is clearly medically counterproducti ... | 2009 | 20037647 |
| amoebal pathogens as emerging causal agents of pneumonia. | abstract despite using modern microbiological diagnostic approaches, the aetiological agents of pneumonia remain unidentified in about 50% of cases. some bacteria that grow poorly or not at all in axenic media used in routine clinical bacteriology laboratory but which can develop inside amoebae may be the agents of these lower respiratory tract infections (rtis) of unexplained aetiology. such amoebae-resisting bacteria, which coevolved with amoebae to resist their microbicidal machinery, may hav ... | 2009 | 20113355 |
| comparison of five commercial serological tests for the detection of anti-chlamydia trachomatis antibodies. | screening for chlamydia trachomatis-specific antibodies is valuable in investigating recurrent miscarriage, tubal infertility and extrauterine pregnancy. we compared here the performance of immunofluorescence (if) to four other commercial tests in detecting igg antibodies directed against c. trachomatis: two enzyme-linked immunosorbent assays (elisas) using the major outer membrane protein (momp) as the antigen, commercialised respectively by medac and r-biopharm (rb), one elisa using the chlamy ... | 2010 | 20349260 |
| parachlamydia involvement in bovine abortions in a beef herd in scotland. | | 2010 | 20453242 |
| proteomic aspects of parachlamydia acanthamoebae infection in acanthamoeba spp. | the free-living but facultatively pathogenic amoebae of the genus acanthamoeba are frequently infected with bacterial endosymbionts that can have a profound influence on the physiology and viability of their host. parachlamydia acanthamoebae, a chlamydial endosymbiont in acanthamoebae, is known to be either symbiotic or lytic to its host, depending on the ambient conditions, for example, temperature. moreover, parachlamydiae can also inhibit the encystment process in acanthamoeba, an essential s ... | 2010 | 20485385 |
| identification of chlamydial species in crocodiles and chickens by pcr-hrm curve analysis. | recently, a pcr protocol (16sg), targeting 16s rrna gene coupled with high resolution melt (hrm) curve analysis was developed in our laboratory and shown to reliably detect and identify the seven different chlamydiaceae spp. in this study, the potential of this method was assessed for detection and differentiation of chlamydiosis in clinical specimens. of the total number of 733 specimens from a range of animal species, 219 (30%) were found positive by 16sg pcr. when a sufficient amount of dna w ... | 2010 | 20570064 |
| fastidious intracellular bacteria as causal agents of community-acquired pneumonia. | intracellular bacteria are common causes of community-acquired pneumonia that grow poorly or not at all on standard culture media and do not respond to beta-lactam antibiotic therapy. apart from well-established agents of pneumonia such as legionella pneumophila, mycoplasma pneumoniae, chlamydia pneumoniae, chlamydia psittaci and coxiella burnetii, some new emerging pathogens have recently been recognized, mainly parachlamydia acanthamoebae and simkania negevensis, two chlamydia-related bacteria ... | 2010 | 20586563 |
| parachlamydia acanthamoebae in domestic cats with and without corneal disease. | corneal samples of cats with and without corneal diseases were screened with a pan-chlamydiales pcr and specific pcrs for parachlamydia, protochlamydia, chlamydophila felis, acanthamoeba and feline herpesviruses (fhv-1). several corneal samples tested positive for parachlamydia and related chlamydiales, indicating cat exposure to these intracellular bacteria. | 2010 | 20618801 |
| impact of free-living amoebae on presence of parachlamydia acanthamoebae in the hospital environment and its survival in vitro without requirement for amoebae. | parachlamydia acanthamoebae is an obligately intracellular bacterium that infects free-living amoebae and is a potential human pathogen in hospital-acquired pneumonia. we examined whether the presence of p. acanthamoebae is related to the presence of acanthamoeba in an actual hospital environment and assessed the in vitro survival of p. acanthamoebae. ninety smear samples were collected between november 2007 and march 2008 (trial 1, n = 52) and between october 2008 and february 2009 (trial 2, n ... | 2010 | 20631104 |
| role of myd88 and toll-like receptors 2 and 4 in the sensing of parachlamydia acanthamoebae. | parachlamydia acanthamoebae is a chlamydia-related organism whose pathogenic role in pneumonia is supported by serological and molecular clinical studies and an experimental mouse model of lung infection. toll-like receptors (tlrs) play a seminal role in sensing microbial products and initiating innate immune responses. the aim of this study was to investigate the roles of myd88, tlr2, and tlr4 in the interaction of parachlamydia with macrophages. here, we showed that parachlamydia entered bone- ... | 2010 | 20837714 |
| host range of obligate intracellular bacterium parachlamydia acanthamoebae. | the obligate intracellular bacterium parachlamydia acanthamoebae is a potential human pathogen, but the host range of the bacteria remains unknown. hence, the growth of p. acanthamoebae bn₉ in protozoa (tetrahymena, acanthamoeba, dictyostelium) and mammalian cells (hep-2, vero, thp-1, pma-stimulated thp-1, jurkat) was assessed using an aiu assay which had been previously established by the current authors. p. acanthamoebae grew in acanthamoeba but not in the other cell types. the growth was also ... | 2010 | 21155362 |
| molecular detection of chlamydia-like organisms in cattle drinking water. | a substantial proportion of the causes of infectious bovine abortion remain largely undiagnosed, potentially due to the presence of previously unrecognised infectious agents. recently, several reports have demonstrated the presence of parachlamydia sp. in placental and foetal tissues derived from bovine abortions of unknown aetiology but the route of transmission remains undefined. the drinking water from one such recent case study was analysed for the presence of parachlamydia sp. as a potentia ... | 2011 | 21549530 |
| identification and characterization of the chlamydia trachomatis l2 s-adenosylmethionine transporter. | abstract methylation is essential to the physiology of all cells, including the obligate intracellular bacterium chlamydia. nevertheless, the methylation cycle is under strong reductive evolutionary pressure in chlamydia. only parachlamydia acanthamoebae and waddlia chondrophila genome sequences harbor homologs to metk, encoding the s-adenosylmethionine (sam) synthetase required for synthesis of sam, and to sahh, which encodes the s-adenosylhomocysteine (sah) hydrolase required for detoxificatio ... | 2011 | 21558433 |
| chlamydia-related bacteria in respiratory samples in finland. | chlamydiarelated bacteria, new members of the order chlamydiales, are suggested to be associated with respiratory disease. we used real-time pcr to investigate the prevalence of parachlamydia acanthamoebae, protochlamydia spp., rhabdochlamydia spp., simkania negevensis and waddlia chondrophila in samples taken from patients with suspected respiratory tract infections. of the 531 samples analyzed, the subset of 136 samples contained 16 (11.8%) samples positive for rhabdochlamydia spp. dna. p. aca ... | 2011 | 21612765 |
| waddlia, parachlamydia and chlamydiaceae in bovine abortion. | the etiology remains unknown in many cases of bovine abortion in switzerland. bacteria of the chlamydiales order are known abortive agents, therefore cases of bovine abortion from three representative regions of switzerland were investigated in this study. particularly chlamydiaceae as well as the chlamydia-like organisms waddlia and parachlamydia were of interest, especially because of their possible zoonotic potential. placenta samples (n=343) were tested for these bacteria by different pcr-me ... | 2011 | 21658867 |
| parachlamydia and rhabdochlamydia: emerging agents of community-acquired respiratory infections in children. | | 2011 | 21810733 |
| unity in variety - the pan-genome of the chlamydiae. | chlamydiae are evolutionarily well-separated bacteria that live exclusively within eukaryotic host cells. they include important human pathogens such as chlamydia trachomatis as well as symbionts of protozoa. as these bacteria are experimentally challenging and genetically intractable, our knowledge about them is still limited. in this study, we obtained the genome sequences of simkania negevensis z, waddlia chondrophila 2032/99 and parachlamydia acanthamoebae uv-7. this enabled us to perform th ... | 2011 | 21690563 |
| [Environmental Chlamydiae with medical significance]. | The molecular biological analysis of a chlamydia-like bacterium from Acanthamoeba sp., originated from the nasal mucosa of a female subject, led to the description of the new species Parachlamydia acanthamoebae. It provided the basis for establishing its own family Parachlamydiaceae, which was genetically separated from the traditional Chlamydiaceae. In the following years other chlamydia-like bacteria, replicating within different free-living amoeba species, have been observed. Due to their clo ... | 2011 | 21971886 |
| permissivity of fish cell lines to three chlamydia-related bacteria: waddlia chondrophila, estrella lausannensis and parachlamydia acanthamoebae. | epitheliocystis is an infectious disease affecting gills and skin of various freshwater and marine fishes, associated with high mortality and reduced growth of survivors. candidatus piscichlamydia salmonis and clavochlamydia salmonicola have recently been identified as aetiological agents of epitheliocystis in atlantic salmon. in addition, several other members of the chlamydiales order have been identified in other fish species. to clarify the pathogenicity of chlamydia-like organisms towards f ... | 2011 | 22092560 |
| amoebal host-range, host-free survival and disinfection susceptibility of environmental chlamydiae as compared to chlamydia trachomatis. | the term "chlamydia-like organisms" encompasses obligate intra-cellular bacterial species phylogenetically close to chlamydiaceae. most are associated with free-living amoebae and several could be responsible for respiratory tract infections and abortion in human and animals. despite increasing concern about their pathogenic role, the prevalence, biodiversity, and ecology of chlamydia-related bacteria still remain largely unknown. in this study, six members of the chlamydiales were tested, inclu ... | 2011 | 22141597 |
| insight into cross-talk between intra-amoebal pathogens. | amoebae are phagocytic protists where genetic exchanges might take place between amoeba-resistant bacteria. these amoebal pathogens are able to escape the phagocytic behaviour of their host. they belong to different bacterial phyla and often show a larger genome size than human-infecting pathogens. this characteristic is proposed to be the result of frequent gene exchanges with other bacteria that share a sympatric lifestyle and contrasts with the genome reduction observed among strict human pat ... | 2011 | 22047552 |
| Intracellular bacteria and adverse pregnancy outcomes. | This review considers the role of intracellular bacteria in adverse pregnancy outcomes, such as miscarriage, stillbirths, and preterm labour. The cause of miscarriage, stillbirth and preterm labour often remains unexplained. Intracellular bacteria that grow either poorly or not at all on media used routinely to detect human pathogens could be the aetiological agents of these obstetric conditions. For example, Listeria monocytogenes and Coxiella burnetti are intracellular bacteria that have a pre ... | 2011 | 21884294 |
| lack of effective anti-apoptotic activities restricts growth of parachlamydiaceae in insect cells. | the fundamental role of programmed cell death in host defense is highlighted by the multitude of anti-apoptotic strategies evolved by various microbes, including the well-known obligate intracellular bacterial pathogens chlamydia trachomatis and chlamydia (chlamydophila) pneumoniae. as inhibition of apoptosis is assumed to be essential for a successful infection of humans by these chlamydiae, we analyzed the anti-apoptotic capacity of close relatives that occur as symbionts of amoebae and might ... | 2012 | 22253735 |