The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Adam Polkinghorne - One of the best experts on this subject based on the ideXlab platform.
-
Mini Review: Antimicrobial Control of Chlamydial Infections in Animals: Current Practices and Issues.
Frontiers in microbiology, 2019Co-Authors: Sankhya Bommana, Adam PolkinghorneAbstract:Chlamydia are a genus of successful obligate intracellular pathogens spread across humans, wildlife, and domesticated animals. The most common species reported in livestock in this genus are Chlamydia abortus, Chlamydia psittaci, Chlamydia suis, and Chlamydia pecorum. Chlamydial infections trigger a series of inflammatory disease-related sequelae including arthritis, conjunctivitis, pneumonia, and abortion. Other bacteria in the phylum Chlamydiae have also been reported in livestock and wildlife but their impact on animal health is less clear. Control of chlamydial infections relies on the use of macrolides, fluoroquinolones, and tetracyclines. Tetracycline resistance (TETR) reported for porcine C. suis strains in association with the use of tetracycline feed is a potentially significant concern given experimental evidence highlighting that the genetic elements inferring TETR may be horizontally transferred to other chlamydial species. As documented in human Chlamydia trachomatis infections, relapse of infections, bacterial shedding post-antibiotic treatment, and disease progression despite chlamydial clearance in animals have also been reported. The identification of novel Chlamydiae as well as new animal hosts for previously described chlamydial pathogens should place a renewed emphasis on basic in vivo studies to demonstrate the efficacy of existing and new antimicrobial treatment regimes. Building on recent reviews of antimicrobials limited to C. trachomatis and C. suis, this review will explore the use of antimicrobials, the evidence and factors that influence the treatment failure of chlamydial infections in animals and the future directions in the control of these important veterinary pathogens.
-
Table_1_Mini Review: Antimicrobial Control of Chlamydial Infections in Animals: Current Practices and Issues.DOCX
2019Co-Authors: Sankhya Bommana, Adam PolkinghorneAbstract:Chlamydia are a genus of successful obligate intracellular pathogens spread across humans, wildlife, and domesticated animals. The most common species reported in livestock in this genus are Chlamydia abortus, Chlamydia psittaci, Chlamydia suis, and Chlamydia pecorum. Chlamydial infections trigger a series of inflammatory disease-related sequelae including arthritis, conjunctivitis, pneumonia, and abortion. Other bacteria in the phylum Chlamydiae have also been reported in livestock and wildlife but their impact on animal health is less clear. Control of chlamydial infections relies on the use of macrolides, fluoroquinolones, and tetracyclines. Tetracycline resistance (TETR) reported for porcine C. suis strains in association with the use of tetracycline feed is a potentially significant concern given experimental evidence highlighting that the genetic elements inferring TETR may be horizontally transferred to other chlamydial species. As documented in human Chlamydia trachomatis infections, relapse of infections, bacterial shedding post-antibiotic treatment, and disease progression despite chlamydial clearance in animals have also been reported. The identification of novel Chlamydiae as well as new animal hosts for previously described chlamydial pathogens should place a renewed emphasis on basic in vivo studies to demonstrate the efficacy of existing and new antimicrobial treatment regimes. Building on recent reviews of antimicrobials limited to C. trachomatis and C. suis, this review will explore the use of antimicrobials, the evidence and factors that influence the treatment failure of chlamydial infections in animals and the future directions in the control of these important veterinary pathogens.
-
Culture-independent metagenomics supports discovery of uncultivable bacteria within the genus Chlamydia
Scientific Reports, 2017Co-Authors: Alyce Taylor-brown, Nicole Borel, Labolina Spang, Adam PolkinghorneAbstract:Advances in culture-independent methods have meant that we can more readily detect and diagnose emerging infectious disease threats in humans and animals. Metagenomics is fast becoming a popular tool for detection and characterisation of novel bacterial pathogens in their environment, and is particularly useful for obligate intracellular bacteria such as Chlamydiae that require labour-intensive culturing. We have used this tool to investigate the microbial metagenomes of Chlamydia -positive cloaca and choana samples from snakes. The microbial complexity within these anatomical sites meant that despite previous detection of chlamydial 16S rRNA sequences by single-gene broad-range PCR, only a chlamydial plasmid could be detected in all samples, and a chlamydial chromosome in one sample. Comparative genomic analysis of the latter revealed it represented a novel taxon, Ca . Chlamydia corallus, with genetic differences in regards to purine and pyrimidine metabolism. Utilising statistical methods to relate plasmid phylogeny to the phylogeny of chromosomal sequences showed that the samples also contain additional novel strains of Ca . C. corallus and two putative novel species in the genus Chlamydia . This study highlights the value of metagenomics methods for rapid novel bacterial discovery and the insights it can provide into the biology of uncultivable intracellular bacteria such as Chlamydiae .
-
Chlamydial infections in wildlife–conservation threats and/or reservoirs of ‘spill-over’ infections?
Veterinary microbiology, 2016Co-Authors: Delaney Burnard, Adam PolkinghorneAbstract:Members of the order Chlamydiales are biphasic intracellular pathogens known to cause disease in both humans and animals. As we learn more about the genetic diversity of this group of pathogens, evidence is growing that these bacteria infect a broader range of animal hosts than previously thought. Over 400 host species are now documented globally with the majority of these being wild animals. Given the impact of chlamydial infections on humans and domesticated animals, the identification of members of the order Chlamydiales in wildlife raises significant questions over a) their impact on animal health and b) the relationships to those strains also found in humans and domestic animals. In some species such as the iconic marsupial, the koala, the conservation impact is known with chlamydial infections associated with debilitating disease, however, in general, little is known about the pathogenic potential of Chlamydiae infecting most wildlife hosts. Accumulating evidence suggests contact with wild animals is a risk factor for infections in domestic animals and/or humans. Beyond the well-recognised zoonotic pathogen, Chlamydia psittaci, a range of studies have now reported traditional pathogens in the family Chlamydiaceae such as Chlamydia pecorum, Chlamydia suis, Chlamydia pneumoniae and Chlamydia abortus in wild animals. The spectre of cross-host transmission ‘spill-over’ and ‘spill-back’ in the epidemiology of infections is of potential concern, however, comprehensive epidemiological studies are lacking for most of these. Accurate evaluation of the significance of chlamydial infections in wildlife is otherwise hampered by i) the cross-sectional nature of most impact studies, ii) a lack of standardised diagnostic approaches, iii) limited study sizes, and iv) biases associated with opportunistic sampling.
-
Culture-independent genomic characterisation of Candidatus Chlamydia sanzinia, a novel uncultivated bacterium infecting snakes
BMC Genomics, 2016Co-Authors: Alyce Taylor-brown, Nathan L. Bachmann, Nicole Borel, Adam PolkinghorneAbstract:Background Recent molecular studies have revealed considerably more diversity in the phylum Chlamydiae than was previously thought. Evidence is growing that many of these novel Chlamydiae may be important pathogens in humans and animals. A significant barrier to characterising these novel Chlamydiae is the requirement for culturing. We recently identified a range of novel uncultured Chlamydiae in captive snakes in Switzerland, however, nothing is known about their biology. Using a metagenomics approach, the aim of this study was to characterise the genome of a novel chlamydial taxon from the choana of a captive snake. In doing so, we propose a new candidate species in the genus Chlamydia ( Candidatus Chlamydia sanzinia) and reveal new information about the biological diversity of this important group of pathogens. Results We identified two chlamydial genomic contigs: a 1,113,073 bp contig, and a 7,504 bp contig, representing the chromosome and plasmid of Ca . Chlamydia sanzinia strain 2742-308, respectively. The 998 predicted coding regions include an expanded repertoire of outer membrane proteins (Pmps and Omps), some of which exhibited frameshift mutations, as well as several chlamydial virulence factors such as the translocating actin-recruitment phosphoprotein (Tarp) and macrophage inhibition potentiator (Mip). A suite of putative inclusion membrane proteins were also predicted. Notably, no evidence of a traditional chlamydial plasticity zone was identified. Phylogenetically, Ca . Chlamydia sanzinia forms a clade with C. pneumoniae and C. pecorum , distinct from former “ Chlamydophila ” species. Conclusions Genomic characterisation of a novel uncultured Chlamydiae from the first reptilian host has expanded our understanding of the diversity and biology of a genus that was thought to be the most well-characterised in this unique phylum. It is anticipated that this method will be suitable for characterisation of other novel Chlamydiae.
Nicole Borel - One of the best experts on this subject based on the ideXlab platform.
-
Novel Chlamydia species isolated from snakes are temperature-sensitive and exhibit decreased susceptibility to azithromycin
Scientific Reports, 2018Co-Authors: Eveline Staub, Gilbert Greub, Manuela Donati, Hanna Marti, Roberta Biondi, Aurora Levi, Cory Ann Leonard, Trestan Pillonel, Helena M. B. Seth-smith, Nicole BorelAbstract:Chlamydia species have recently been recognized as emerging pathogens in snakes. However, isolation of novel snake Chlamydiae is critical and their growth characteristics are largely unknown. In this study, two novel chlamydial species are described: Chlamydia serpentis and Chlamydia poikilothermis , isolated after attempts on 23 cloacal and choanal swabs from 18 PCR-positive captive snakes originating from different Swiss snake collections. Isolation success, growth curve and infectivity rates over a 48-hour time period were dependent on temperature (37 °C for C . serpentis , 28 °C for C . poikilothermis ). C . serpentis and C . poikilothermis were sensitive to tetracycline and moxifloxacin during evaluation by in vitro antibiotic susceptibility assay but intermediate to resistant (2–4 μg/ml) to azithromycin. Whole genome sequencing of the isolates provided proof of the novel species status, and gives insights into the evolution of these branches of genus Chlamydia .
-
Culture-independent metagenomics supports discovery of uncultivable bacteria within the genus Chlamydia
Scientific Reports, 2017Co-Authors: Alyce Taylor-brown, Nicole Borel, Labolina Spang, Adam PolkinghorneAbstract:Advances in culture-independent methods have meant that we can more readily detect and diagnose emerging infectious disease threats in humans and animals. Metagenomics is fast becoming a popular tool for detection and characterisation of novel bacterial pathogens in their environment, and is particularly useful for obligate intracellular bacteria such as Chlamydiae that require labour-intensive culturing. We have used this tool to investigate the microbial metagenomes of Chlamydia -positive cloaca and choana samples from snakes. The microbial complexity within these anatomical sites meant that despite previous detection of chlamydial 16S rRNA sequences by single-gene broad-range PCR, only a chlamydial plasmid could be detected in all samples, and a chlamydial chromosome in one sample. Comparative genomic analysis of the latter revealed it represented a novel taxon, Ca . Chlamydia corallus, with genetic differences in regards to purine and pyrimidine metabolism. Utilising statistical methods to relate plasmid phylogeny to the phylogeny of chromosomal sequences showed that the samples also contain additional novel strains of Ca . C. corallus and two putative novel species in the genus Chlamydia . This study highlights the value of metagenomics methods for rapid novel bacterial discovery and the insights it can provide into the biology of uncultivable intracellular bacteria such as Chlamydiae .
-
Culture-independent genomic characterisation of Candidatus Chlamydia sanzinia, a novel uncultivated bacterium infecting snakes
BMC Genomics, 2016Co-Authors: Alyce Taylor-brown, Nathan L. Bachmann, Nicole Borel, Adam PolkinghorneAbstract:Background Recent molecular studies have revealed considerably more diversity in the phylum Chlamydiae than was previously thought. Evidence is growing that many of these novel Chlamydiae may be important pathogens in humans and animals. A significant barrier to characterising these novel Chlamydiae is the requirement for culturing. We recently identified a range of novel uncultured Chlamydiae in captive snakes in Switzerland, however, nothing is known about their biology. Using a metagenomics approach, the aim of this study was to characterise the genome of a novel chlamydial taxon from the choana of a captive snake. In doing so, we propose a new candidate species in the genus Chlamydia ( Candidatus Chlamydia sanzinia) and reveal new information about the biological diversity of this important group of pathogens. Results We identified two chlamydial genomic contigs: a 1,113,073 bp contig, and a 7,504 bp contig, representing the chromosome and plasmid of Ca . Chlamydia sanzinia strain 2742-308, respectively. The 998 predicted coding regions include an expanded repertoire of outer membrane proteins (Pmps and Omps), some of which exhibited frameshift mutations, as well as several chlamydial virulence factors such as the translocating actin-recruitment phosphoprotein (Tarp) and macrophage inhibition potentiator (Mip). A suite of putative inclusion membrane proteins were also predicted. Notably, no evidence of a traditional chlamydial plasticity zone was identified. Phylogenetically, Ca . Chlamydia sanzinia forms a clade with C. pneumoniae and C. pecorum , distinct from former “ Chlamydophila ” species. Conclusions Genomic characterisation of a novel uncultured Chlamydiae from the first reptilian host has expanded our understanding of the diversity and biology of a genus that was thought to be the most well-characterised in this unique phylum. It is anticipated that this method will be suitable for characterisation of other novel Chlamydiae.
-
culture independent genomic characterisation of candidatus chlamydia sanzinia a novel uncultivated bacterium infecting snakes
BMC Genomics, 2016Co-Authors: Alyce Taylorbrown, Nathan L. Bachmann, Nicole Borel, Adam PolkinghorneAbstract:Background Recent molecular studies have revealed considerably more diversity in the phylum Chlamydiae than was previously thought. Evidence is growing that many of these novel Chlamydiae may be important pathogens in humans and animals. A significant barrier to characterising these novel Chlamydiae is the requirement for culturing. We recently identified a range of novel uncultured Chlamydiae in captive snakes in Switzerland, however, nothing is known about their biology. Using a metagenomics approach, the aim of this study was to characterise the genome of a novel chlamydial taxon from the choana of a captive snake. In doing so, we propose a new candidate species in the genus Chlamydia (Candidatus Chlamydia sanzinia) and reveal new information about the biological diversity of this important group of pathogens.
-
Mixed infections with Chlamydia and porcine epidemic diarrhea virus - a new in vitro model of chlamydial persistence
BMC Microbiology, 2010Co-Authors: Nicole Borel, Claudia Dumrese, Urs Ziegler, Andrea Schifferli, Carmen Kaiser, Andreas PospischilAbstract:Background Chlamydiae induce persistent infections, which have been associated with a wide range of chronic diseases in humans and animals. Mixed infections with Chlamydia and porcine epidemic diarrhea virus (PEDV) may result in generation of persistent chlamydial infections. To test this hypothesis, an in vitro model of dual infection with cell culture-adapted PEDV and Chlamydia abortus or Chlamydia pecorum in Vero cells was established. Results Infected cultures were investigated by immunofluorescence (IF), transmission electron microscopy (TEM) and re-infection experiments. By IF, Chlamydia -infected cells showed normal inclusions after 39 hpi. Dual infections with Chlamydia abortus revealed a heterogenous mix of inclusion types including small inclusions consisting of aberrant bodies (ABs), medium-sized inclusions consisting of ABs and reticulate bodies and normal inclusions. Only aberrant inclusions were observable in dual infection experiments with Chlamydia pecorum and PEDV. TEM examinations of mixed infections with Chlamydia abortus and Chlamydia pecorum revealed aberrant chlamydial inclusions containing reticulate-like, pleomorphic ABs, which were up to 2 μm in diameter. No re-differentiation into elementary bodies (EBs) was detected. In re-infection experiments, co-infected cells produced fewer EBs than monoinfected cells. Conclusions In the present study we confirm that PEDV co-infection alters the developmental cycle of member species of the family Chlamydiaceae , in a similar manner to other well-described persistence induction methods. Interestingly, this effect appears to be partially species-specific as Chlamydia pecorum appears more sensitive to PEDV co-infection than Chlamydia abortus , as evidenced by TEM and IF observations of a homogenous population of aberrant inclusions in PEDV - Chlamydia pecorum co-infections.
Konrad Sachse - One of the best experts on this subject based on the ideXlab platform.
-
unity in variety the pan genome of the Chlamydiae
Molecular Biology and Evolution, 2011Co-Authors: Astrid Collingro, Eva Heinz, Patrick Tischler, Patrik M Bavoil, Robert C Brunham, Thomas Weinmaier, Thomas Penz, Timothy D. Read, Konrad SachseAbstract: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 the first comprehensive comparative and phylogenomic analysis of representative members of four major families of the Chlamydiae, including the Chlamydiaceae. We identified a surprisingly large core gene set present in all genomes and a high number of diverse accessory genes in those Chlamydiae that do not primarily infect humans or animals, including a chemosensory system in P. acanthamoebae and a type IV secretion system. In S. negevensis, the type IV secretion system is encoded on a large conjugative plasmid (pSn, 132 kb). Phylogenetic analyses suggested that a plasmid similar to the S. negevensis plasmid was originally acquired by the last common ancestor of all four families and that it was subsequently reduced, integrated into the chromosome, or lost during diversification, ultimately giving rise to the extant virulence-associated plasmid of pathogenic Chlamydiae. Other virulence factors, including a type III secretion system, are conserved among the Chlamydiae to variable degrees and together with differences in the composition of the cell wall reflect adaptation to different host cells including convergent evolution among the four chlamydial families. Phylogenomic analysis focusing on chlamydial proteins with homology to plant proteins provided evidence for the acquisition of 53 chlamydial genes by a plant progenitor, lending further support for the hypothesis of an early interaction between a chlamydial ancestor and the primary photosynthetic eukaryote.
-
Unity in Variety—The Pan-Genome of the Chlamydiae
Molecular biology and evolution, 2011Co-Authors: Astrid Collingro, Eva Heinz, Patrick Tischler, Konrad Sachse, Patrik M Bavoil, Robert C Brunham, Thomas Weinmaier, Thomas Penz, Timothy D. Read, Simona KahaneAbstract: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 the first comprehensive comparative and phylogenomic analysis of representative members of four major families of the Chlamydiae, including the Chlamydiaceae. We identified a surprisingly large core gene set present in all genomes and a high number of diverse accessory genes in those Chlamydiae that do not primarily infect humans or animals, including a chemosensory system in P. acanthamoebae and a type IV secretion system. In S. negevensis, the type IV secretion system is encoded on a large conjugative plasmid (pSn, 132 kb). Phylogenetic analyses suggested that a plasmid similar to the S. negevensis plasmid was originally acquired by the last common ancestor of all four families and that it was subsequently reduced, integrated into the chromosome, or lost during diversification, ultimately giving rise to the extant virulence-associated plasmid of pathogenic Chlamydiae. Other virulence factors, including a type III secretion system, are conserved among the Chlamydiae to variable degrees and together with differences in the composition of the cell wall reflect adaptation to different host cells including convergent evolution among the four chlamydial families. Phylogenomic analysis focusing on chlamydial proteins with homology to plant proteins provided evidence for the acquisition of 53 chlamydial genes by a plant progenitor, lending further support for the hypothesis of an early interaction between a chlamydial ancestor and the primary photosynthetic eukaryote.
-
Recurrence of Chlamydia suis infection in pigs after short-term antimicrobial treatment
Veterinary journal (London England : 1997), 2010Co-Authors: Petra Reinhold, Elisabeth M. Liebler-tenorio, Stephanie Sattler, Konrad SachseAbstract:The effect of short-term antimicrobial treatment on natural excretion of Chlamydia suis in rectal swabs and C. suis and Chlamydophila psittaci in nasal swabs was investigated in 47 clinically normal piglets by quantitative real-time PCR. Pigs were treated IM with 4 mg/kg enrofloxacin for 5 days (n = 22) or 2.5 mg/kg enrofloxacin for 3 days followed by 100 mg/mL tiamulin (n = 25). Antimicrobial treatment reduced the number of pigs positive for Chlamydiae and the quantity of chlamydial DNA in positive swabs for a few days, but chlamydial excretion recurred in both groups. Short-term antimicrobial treatment at dosages recommended for treatment of other bacterial infections in pig herds was not effective in eliminating naturally occurring subclinical chlamydial infection in pigs. (C) 2010 Elsevier Ltd. All rights reserved
-
Chlamydiae in oviducts and uteri of repeat breeder pigs
Theriogenology, 2006Co-Authors: Johannes Kauffold, Helmut Hotzel, Angela Berndt, Falk Melzer, Grit Hoffmann, Konrad SachseAbstract:Chlamydial infections of the genital organs cause reproductive failure in female pigs, and the uterus is recognized a target tissue for an infection. In contrast, information on the effect of Chlamydiae on the porcine oviduct is patchily and inconclusive, although the bacteria are known to cause severe tubal defects in humans and laboratory animals. The aim of this study was to examine the segments ampulla (A), isthmus (I) and utero-tubal junction of the left (n = 20) or both (n = 22) oviducts, and uteri (U) from 42 culled repeat breeder pigs for Chlamydiae using ompA-PCR, partial ompA gene sequencing, immunohistochemistry (IHC) and microscopy of tissue specimens for histopathology. As revealed by PCR, among a total of 26 chlamydia-positive females, 19 were tested positive in one or more segments of one or both oviducts, 14 were found positive in the uterus, and concomitant infections of both organs were observed in 7 of them. Sequencing of 33 PCR products revealed the following chlamydial species: Chlamydophila (Cp.) psittaci (n = 18), Cp. abortus (n = 2), Chlamydia (C.) suis (n = 10), and C. trachomatis (n = 3). Immunopositive staining was observed within the surface epithelium (in A, I, U), stromal tissue (in I, U) and muscular layer (in A, I, U). A total of 24 females had inflamed oviductal segments (in A and/or I) and 36 inflamed uteri. However, there was no relationship between histopathology and results of PCR or IHC. In conclusion, Chlamydiae were found to infect oviducts and uteri of pigs. Further studies are required to clarify whether chlamydial infection causes specific histopathology and alters tubal function.
-
Prevalence of Chlamydiae in boars and semen used for artificial insemination.
Theriogenology, 2005Co-Authors: Johannes Kauffold, Falk Melzer, Klaus Henning, Katrin Schulze, Claus Leiding, Konrad SachseAbstract:Although there are indications for venereal transmission of Chlamydiae in pigs, direct diagnostic evidence on the presence of these bacteria in boars and boar semen in particular is still incomplete. We investigated boars from two studs (A, B) in semen (A: n = 174; B: n = 100) and faeces (A: n = 174; B: n = 24) for Chlamydiae using ompA-PCR and partial ompA gene sequencing. Additionally, blood serum was examined for chlamydial antibodies using an indirect ELISA (A: n = 171; B: n = 62). Chlamydiae were found in 9 (5.2%) and 24 (24.0%) semen specimens, and in 71 (40.1%) and 2 (8.3%) faecal samples from boars of stud A and B, respectively. Regarding individual chlamydial species, Chlamydophila psittaci and Chlamydia suis were identified most frequently, with the former predominating in semen (in 23 out of 33 positive samples) and the latter in faeces (68/73). In contrast, Chlamydophila pecorum was found only sporadically. Chlamydial antibodies were detected in 80 (46.8%) and 6 (9.7%) boars of stud A and B, respectively. No correlation was observed between the data from serology and PCR of semen or faeces in either of the studs. In conclusion, detection of Chlamydiae in semen of boars suggests a potential for venereal transmission. Whether the high overall prevalence of chlamydial infections reflects a general situation in boars needs to be investigated. Serological testing failed to identify boars shedding Chlamydiae in their semen.
Eva Heinz - One of the best experts on this subject based on the ideXlab platform.
-
unity in variety the pan genome of the Chlamydiae
Molecular Biology and Evolution, 2011Co-Authors: Astrid Collingro, Eva Heinz, Patrick Tischler, Patrik M Bavoil, Robert C Brunham, Thomas Weinmaier, Thomas Penz, Timothy D. Read, Konrad SachseAbstract: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 the first comprehensive comparative and phylogenomic analysis of representative members of four major families of the Chlamydiae, including the Chlamydiaceae. We identified a surprisingly large core gene set present in all genomes and a high number of diverse accessory genes in those Chlamydiae that do not primarily infect humans or animals, including a chemosensory system in P. acanthamoebae and a type IV secretion system. In S. negevensis, the type IV secretion system is encoded on a large conjugative plasmid (pSn, 132 kb). Phylogenetic analyses suggested that a plasmid similar to the S. negevensis plasmid was originally acquired by the last common ancestor of all four families and that it was subsequently reduced, integrated into the chromosome, or lost during diversification, ultimately giving rise to the extant virulence-associated plasmid of pathogenic Chlamydiae. Other virulence factors, including a type III secretion system, are conserved among the Chlamydiae to variable degrees and together with differences in the composition of the cell wall reflect adaptation to different host cells including convergent evolution among the four chlamydial families. Phylogenomic analysis focusing on chlamydial proteins with homology to plant proteins provided evidence for the acquisition of 53 chlamydial genes by a plant progenitor, lending further support for the hypothesis of an early interaction between a chlamydial ancestor and the primary photosynthetic eukaryote.
-
Unity in Variety—The Pan-Genome of the Chlamydiae
Molecular biology and evolution, 2011Co-Authors: Astrid Collingro, Eva Heinz, Patrick Tischler, Konrad Sachse, Patrik M Bavoil, Robert C Brunham, Thomas Weinmaier, Thomas Penz, Timothy D. Read, Simona KahaneAbstract: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 the first comprehensive comparative and phylogenomic analysis of representative members of four major families of the Chlamydiae, including the Chlamydiaceae. We identified a surprisingly large core gene set present in all genomes and a high number of diverse accessory genes in those Chlamydiae that do not primarily infect humans or animals, including a chemosensory system in P. acanthamoebae and a type IV secretion system. In S. negevensis, the type IV secretion system is encoded on a large conjugative plasmid (pSn, 132 kb). Phylogenetic analyses suggested that a plasmid similar to the S. negevensis plasmid was originally acquired by the last common ancestor of all four families and that it was subsequently reduced, integrated into the chromosome, or lost during diversification, ultimately giving rise to the extant virulence-associated plasmid of pathogenic Chlamydiae. Other virulence factors, including a type III secretion system, are conserved among the Chlamydiae to variable degrees and together with differences in the composition of the cell wall reflect adaptation to different host cells including convergent evolution among the four chlamydial families. Phylogenomic analysis focusing on chlamydial proteins with homology to plant proteins provided evidence for the acquisition of 53 chlamydial genes by a plant progenitor, lending further support for the hypothesis of an early interaction between a chlamydial ancestor and the primary photosynthetic eukaryote.
-
Comprehensive in silico prediction and analysis of chlamydial outer membrane proteins reflects evolution and life style of the Chlamydiae
BMC Genomics, 2009Co-Authors: Eva Heinz, Patrick Tischler, Thomas Rattei, Garry Myers, Michael Wagner, Matthias HornAbstract:Background Chlamydiae are obligate intracellular bacteria comprising some of the most important bacterial pathogens of animals and humans. Although chlamydial outer membrane proteins play a key role for attachment to and entry into host cells, only few have been described so far. We developed a comprehensive, multiphasic in silico approach, including the calculation of clusters of orthologues, to predict outer membrane proteins using conservative criteria. We tested this approach using Escherichia coli (positive control) and Bacillus subtilis (negative control), and applied it to five chlamydial species; Chlamydia trachomatis , Chlamydia muridarum , Chlamydia (a.k.a. Chlamydophila ) pneumoniae , Chlamydia (a.k.a. Chlamydophila ) caviae , and Protochlamydia amoebophila . Results In total, 312 chlamydial outer membrane proteins and lipoproteins in 88 orthologous clusters were identified, including 238 proteins not previously recognized to be located in the outer membrane. Analysis of their taxonomic distribution revealed an evolutionary conservation among Chlamydiae , Verrucomicrobia , Lentisphaerae and Planctomycetes as well as lifestyle-dependent conservation of the chlamydial outer membrane protein composition. Conclusion This analysis suggested a correlation between the outer membrane protein composition and the host range of Chlamydiae and revealed a common set of outer membrane proteins shared by these intracellular bacteria. The collection of predicted chlamydial outer membrane proteins is available at the online database pCOMP http://www.microbial-ecology.net/pcomp and might provide future guidance in the quest for anti-chlamydial vaccines.
-
Comprehensive in silico prediction and analysis of chlamydial outer membrane proteins reflects evolution and life style of the Chlamydiae
BMC genomics, 2009Co-Authors: Eva Heinz, Patrick Tischler, Thomas Rattei, Michael Wagner, Garry S A Myers, Matthias HornAbstract:Chlamydiae are obligate intracellular bacteria comprising some of the most important bacterial pathogens of animals and humans. Although chlamydial outer membrane proteins play a key role for attachment to and entry into host cells, only few have been described so far. We developed a comprehensive, multiphasic in silico approach, including the calculation of clusters of orthologues, to predict outer membrane proteins using conservative criteria. We tested this approach using Escherichia coli (positive control) and Bacillus subtilis (negative control), and applied it to five chlamydial species; Chlamydia trachomatis, Chlamydia muridarum, Chlamydia (a.k.a. Chlamydophila) pneumoniae, Chlamydia (a.k.a. Chlamydophila) caviae, and Protochlamydia amoebophila. In total, 312 chlamydial outer membrane proteins and lipoproteins in 88 orthologous clusters were identified, including 238 proteins not previously recognized to be located in the outer membrane. Analysis of their taxonomic distribution revealed an evolutionary conservation among Chlamydiae, Verrucomicrobia, Lentisphaerae and Planctomycetes as well as lifestyle-dependent conservation of the chlamydial outer membrane protein composition. This analysis suggested a correlation between the outer membrane protein composition and the host range of Chlamydiae and revealed a common set of outer membrane proteins shared by these intracellular bacteria. The collection of predicted chlamydial outer membrane proteins is available at the online database pCOMP http://www.microbial-ecology.net/pcomp and might provide future guidance in the quest for anti-chlamydial vaccines.
Matthias Horn - One of the best experts on this subject based on the ideXlab platform.
-
Comprehensive in silico prediction and analysis of chlamydial outer membrane proteins reflects evolution and life style of the Chlamydiae
BMC Genomics, 2009Co-Authors: Eva Heinz, Patrick Tischler, Thomas Rattei, Garry Myers, Michael Wagner, Matthias HornAbstract:Background Chlamydiae are obligate intracellular bacteria comprising some of the most important bacterial pathogens of animals and humans. Although chlamydial outer membrane proteins play a key role for attachment to and entry into host cells, only few have been described so far. We developed a comprehensive, multiphasic in silico approach, including the calculation of clusters of orthologues, to predict outer membrane proteins using conservative criteria. We tested this approach using Escherichia coli (positive control) and Bacillus subtilis (negative control), and applied it to five chlamydial species; Chlamydia trachomatis , Chlamydia muridarum , Chlamydia (a.k.a. Chlamydophila ) pneumoniae , Chlamydia (a.k.a. Chlamydophila ) caviae , and Protochlamydia amoebophila . Results In total, 312 chlamydial outer membrane proteins and lipoproteins in 88 orthologous clusters were identified, including 238 proteins not previously recognized to be located in the outer membrane. Analysis of their taxonomic distribution revealed an evolutionary conservation among Chlamydiae , Verrucomicrobia , Lentisphaerae and Planctomycetes as well as lifestyle-dependent conservation of the chlamydial outer membrane protein composition. Conclusion This analysis suggested a correlation between the outer membrane protein composition and the host range of Chlamydiae and revealed a common set of outer membrane proteins shared by these intracellular bacteria. The collection of predicted chlamydial outer membrane proteins is available at the online database pCOMP http://www.microbial-ecology.net/pcomp and might provide future guidance in the quest for anti-chlamydial vaccines.
-
Comprehensive in silico prediction and analysis of chlamydial outer membrane proteins reflects evolution and life style of the Chlamydiae
BMC genomics, 2009Co-Authors: Eva Heinz, Patrick Tischler, Thomas Rattei, Michael Wagner, Garry S A Myers, Matthias HornAbstract:Chlamydiae are obligate intracellular bacteria comprising some of the most important bacterial pathogens of animals and humans. Although chlamydial outer membrane proteins play a key role for attachment to and entry into host cells, only few have been described so far. We developed a comprehensive, multiphasic in silico approach, including the calculation of clusters of orthologues, to predict outer membrane proteins using conservative criteria. We tested this approach using Escherichia coli (positive control) and Bacillus subtilis (negative control), and applied it to five chlamydial species; Chlamydia trachomatis, Chlamydia muridarum, Chlamydia (a.k.a. Chlamydophila) pneumoniae, Chlamydia (a.k.a. Chlamydophila) caviae, and Protochlamydia amoebophila. In total, 312 chlamydial outer membrane proteins and lipoproteins in 88 orthologous clusters were identified, including 238 proteins not previously recognized to be located in the outer membrane. Analysis of their taxonomic distribution revealed an evolutionary conservation among Chlamydiae, Verrucomicrobia, Lentisphaerae and Planctomycetes as well as lifestyle-dependent conservation of the chlamydial outer membrane protein composition. This analysis suggested a correlation between the outer membrane protein composition and the host range of Chlamydiae and revealed a common set of outer membrane proteins shared by these intracellular bacteria. The collection of predicted chlamydial outer membrane proteins is available at the online database pCOMP http://www.microbial-ecology.net/pcomp and might provide future guidance in the quest for anti-chlamydial vaccines.
-
Chlamydiae as symbionts in eukaryotes
Annual Review of Microbiology, 2008Co-Authors: Matthias HornAbstract:Members of the phylum Chlamydiae are obligate intracellular bacteria that were discovered about a century ago. Although Chlamydiae are major pathogens of humans and animals, they were long recognized only as a phylogenetically well-separated, small group of closely related microorganisms. The diversity of Chlamydiae, their host range, and their occurrence in the environment had been largely underestimated. Today, several chlamydia-like bacteria have been described as symbionts of free-living amoebae and other eukaryotic hosts. Some of these environmental Chlamydiae might also be of medical relevance for humans. Their analysis has contributed to a broader understanding of chlamydial biology and to novel insights into the evolution of these unique microorganisms.
-
Detection and differentiation of Chlamydiae by fluorescence in situ hybridization.
Applied and environmental microbiology, 2002Co-Authors: Sven Poppert, Michael Wagner, Andreas Essig, Reinhard Marre, Matthias HornAbstract: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 evaluation of a hierarchic probe set for the specific detection and differentiation of Chlamydiae, particularly C. pneumoniae, C. trachomatis, C. psittaci, and the recently described chlamydia-like bacteria comprising the novel genera Neochlamydia and Parachlamydia. The specificity of the nine newly developed probes was successfully demonstrated by in situ hybridization of experimentally infected amoebae and HeLa 229 cells, including HeLa 229 cells coinfected with C. pneumoniae and C. trachomatis. FISH reliably stained chlamydial inclusions as early as 12 h postinfection. The sensitivity of FISH was further confirmed by combination with direct fluorescence antibody staining. In contrast to previously established detection methods for Chlamydiae, FISH was not susceptible to false-positive results and allows the detection of all recognized Chlamydiae in one single step.