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Hagenbuch F, Loehrer S, Marti H, Kasimov V, Jelocnik M, Borel N. Investigation of Chlamydia pecorum in livestock from Switzerland reveals a high degree of diversity in bovine strains. Vet Microbiol 2024; 292:110057. [PMID: 38502978 DOI: 10.1016/j.vetmic.2024.110057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/11/2024] [Accepted: 03/15/2024] [Indexed: 03/21/2024]
Abstract
Chlamydia pecorum is a widespread veterinary chlamydial species causing endemic infections in livestock, such as ruminants and pigs, globally. However, there is limited contemporary knowledge on infecting strain diversity in various hosts. This study aimed to evaluate the genetic diversity of C. pecorum strains infecting Swiss livestock through C. pecorum genotyping and phylogenetic analyses in comparison to the global population, while also assessing chlamydial strains for plasmid carriage. A total of 263 C. pecorum positive samples from clinically healthy ruminant and pig herds (Bovines = 216, sheep = 25, pigs = 14) as well as placentae from eight C. pecorum positive ruminant abortion cases from other Swiss herds were investigated. The ompA and Multi-Locus sequence typing revealed novel C. pecorum genotypes, and bovine strains exhibited considerable genetic diversity, contrasting with lower diversity in sheep and pig strains. C. pecorum plasmid was detected in 100.0% of sheep (41/41) and pig (255/255) samples, and in 69.4% of bovine samples (150/216). In contrast, no plasmid was detected in the eight C. pecorum-positive ruminant abortion cases either representing plasmid-less strains or possibly escaping PCR detection due to autolysis of the placenta. This study supports the genetic diversity of C. pecorum strains, particularly in bovines, and identifies novel sequence types in Swiss livestock.
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Affiliation(s)
- Fabian Hagenbuch
- Institute of Veterinary Pathology, Vetsuisse-Faculty, University of Zurich, Zurich 8057, Switzerland
| | - Samuel Loehrer
- Institute of Veterinary Pathology, Vetsuisse-Faculty, University of Zurich, Zurich 8057, Switzerland
| | - Hanna Marti
- Institute of Veterinary Pathology, Vetsuisse-Faculty, University of Zurich, Zurich 8057, Switzerland
| | - Vasilli Kasimov
- School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia; Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, 4556, Australia
| | - Martina Jelocnik
- School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia; Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, 4556, Australia
| | - Nicole Borel
- Institute of Veterinary Pathology, Vetsuisse-Faculty, University of Zurich, Zurich 8057, Switzerland.
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Chlamydia pecorum Ovine Abortion: Associations between Maternal Infection and Perinatal Mortality. Pathogens 2021; 10:pathogens10111367. [PMID: 34832523 PMCID: PMC8618313 DOI: 10.3390/pathogens10111367] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 12/29/2022] Open
Abstract
Chlamydia pecorum is a common gastrointestinal inhabitant of livestock but infections can manifest in a broad array of clinical presentations and in a range of host species. While C. pecorum is a known cause of ovine abortion, clinical cases have only recently been described in detail. Here, the prevalence and sequence types (STs) of C. pecorum in ewes from a property experiencing high levels of perinatal mortality (PNM) in New South Wales (NSW), Australia, were investigated using serological and molecular methods. Ewes that were PNM+ were statistically more likely to test seropositive compared to PNM− ewes and displayed higher antibody titres; however, an increase in chlamydial shedding from either the rectum, vagina or conjunctiva of PNM+ ewes was not observed. Multilocus sequence typing (MLST) indicated that C. pecorum ST23 was the major ST shed by ewes in the flock, was the only ST identified from the vaginal site, and was the same ST detected within aborted foetal tissues. Whole genome sequencing of C. pecorum isolated from one abortion case revealed that the C. pecorum plasmid (pCpec) contained a unique deletion in coding sequence 1 (CDS1) that was also present in C. pecorum ST23 shed from the ewes. A further unique deletion was noted in a polymorphic membrane protein gene (pmpG) of the C. pecorum chromosome, which warrants further investigation given the role of PmpG in host cell adherence and tissue tropism.This study describes novel infection parameters in a sheep flock experiencing C. pecorum-associated perinatal mortality, provides the first genomic data from an abortigenic C. pecorum strain, and raises questions about possible links between unique genetic features of this strain and C. pecorum abortion.
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Rohner L, Marti H, Torgerson P, Hoffmann K, Jelocnik M, Borel N. Prevalence and molecular characterization of C. pecorum detected in Swiss fattening pigs. Vet Microbiol 2021; 256:109062. [PMID: 33848714 DOI: 10.1016/j.vetmic.2021.109062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/24/2021] [Indexed: 11/25/2022]
Abstract
Chlamydia (C.) pecorum, an obligate intracellular bacterial species commonly found in ruminants, can also occur in pigs. However, its significance as a potential porcine pathogen, or commensal, is still unclear. In a previous study (Hoffmann et al. 2015), mixed infections of C. suis and C. pecorum were detected in 14 Swiss fattening pig farms. Using these samples, we aimed to investigate the infection dynamics of C. suis and C. pecorum mixed infections in these farms. In addition, we analyzed the genetic diversity of Swiss porcine C. pecorum strains in relation to globally circulating strains. In total, 1284 conjunctival and rectal swabs from 391 pigs, collected at the beginning and end of the fattening period, were tested during the course of this study. We determined the bacterial loads of C. suis and C. pecorum using species-specific real-time PCR (qPCR) and compared these results to already existing DNA-microarray and Chlamydiaceae qPCR data. Overall, C. suis and Chlamydiaceae copy numbers decreased in the course of the fattening period, whereas C. pecorum copy numbers increased. No association was found between clinical signs (conjunctivitis, lameness and diarrhea) and the bacterial loads. Preventive antibiotic treatment at the beginning of the fattening period significantly lowered the chlamydial load and outdoor access was associated with higher loads. Proximity to the nearest ruminants correlated with increased C. pecorum loads, indicating that C. pecorum could be transmitted from ruminants to pigs. Multi-locus sequence typing (MLST) and major outer membrane protein (ompA) genotyping revealed two novel sequence types (STs) (301, 302) and seven unique ompA genotypes (1-7) that appear to form a specific clade separate from other European C. pecorum strains.
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Affiliation(s)
- Lea Rohner
- Institute of Veterinary Pathology, Vetsuisse-Faculty University Zurich, Zurich, 8057, Switzerland; Center for Clinical Studies, Vetsuisse-Faculty, University of Zurich, Zurich, 8057, Switzerland
| | - Hanna Marti
- Institute of Veterinary Pathology, Vetsuisse-Faculty University Zurich, Zurich, 8057, Switzerland; Center for Clinical Studies, Vetsuisse-Faculty, University of Zurich, Zurich, 8057, Switzerland.
| | - Paul Torgerson
- Section of Veterinary Epidemiology, Vetsuisse-Faculty, University of Zurich, Zurich, 8057, Switzerland
| | - Karolin Hoffmann
- Institute of Veterinary Pathology, Vetsuisse-Faculty University Zurich, Zurich, 8057, Switzerland; Center for Clinical Studies, Vetsuisse-Faculty, University of Zurich, Zurich, 8057, Switzerland
| | - Martina Jelocnik
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, 4556, Queensland, Australia
| | - Nicole Borel
- Institute of Veterinary Pathology, Vetsuisse-Faculty University Zurich, Zurich, 8057, Switzerland; Center for Clinical Studies, Vetsuisse-Faculty, University of Zurich, Zurich, 8057, Switzerland
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Molecular Detection and Identification of Chlamydiaceae in the Eyes of Wild and Domestic Ruminant Hosts from Northern Spain. Pathogens 2021; 10:pathogens10030383. [PMID: 33806840 PMCID: PMC8005166 DOI: 10.3390/pathogens10030383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 11/17/2022] Open
Abstract
Infections by Chlamydiae are associated with ocular disease in humans and animals. In this study, the presence and diversity of Chlamydia spp. was assessed in diseased and healthy eyes of domestic sheep and wild ruminants that share mountain habitats in northern Spain. The presence of Chlamydia spp. was tested by real-time PCR in 1786 conjunctival swabs collected from both eyes of 893 animals from mountain habitats in northern Spain, and chlamydial species were identified in the positive samples by ArrayTube microarray methods. Chlamydial DNA was detected in 0.6% (CI95% 0.2–1.3) of the Pyrenean chamois (Rupicapra pyrenaica) and 1.4% (CI95% <0.01–8.1) of the sheep (Ovis aries) sampled, with Chlamydia pecorum the only chlamydial species identified. No association of C. pecorum with ocular disease or co-infection with Mycoplasma conjunctivae was found. Further studies on the pathogenesis of infectious keratoconjunctivitis are needed to better understand the ecology of C. pecorum and its possible role as a ruminant pathogen at the wildlife–livestock interface.
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Jelocnik M, Taylor-Brown A, O'Dea C, Anstey S, Bommana S, Masters N, Katouli M, Jenkins C, Polkinghorne A. Detection of a range of genetically diverse chlamydiae in Australian domesticated and wild ungulates. Transbound Emerg Dis 2019; 66:1132-1137. [PMID: 30873753 DOI: 10.1111/tbed.13171] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 12/18/2022]
Abstract
Chlamydiae are globally widespread obligate intracellular bacteria, which several species are a well-recognized threat to human and animal health. In Australia, the most successful chlamydial species are the infamous koala pathogen C. pecorum, and C. psittaci, an emerging pathogen associated with zoonotic events. Little is known about infections caused by other chlamydial organisms in Australian livestock or wildlife. Considering that these hosts can be encountered by humans at the animal/human interface, in this study, we investigated genetic diversity of chlamydial organisms infecting Australian domesticated and wild ungulates. A total of 185 samples from 129 domesticated (cattle, horses, sheep, and pigs) and 29 wild (deer) ungulate hosts were screened with C. pecorum and C. psittaci species-specific assays, followed by a screen with pan-Chlamydiales assay. Overall, chlamydial DNA was detected in 120/185 (65%) samples, including all ungulate hosts. Species-specific assays further revealed that C. pecorum and C. psittaci DNA were detected in 27% (50/185) and 6% (11/185) of the samples, respectively, however from domesticated hosts only. A total of 46 "signature" 16S rRNA sequences were successfully resolved by sequencing and were used for phylogenetic analyses. Sequence analyses revealed that genetically diverse novel as well as traditional chlamydial organisms infect an expanded range of ungulate hosts in Australia. Detection of the C. psittaci and C. pecorum in livestock, and novel taxa infecting horses and deer raises questions about the genetic make-up and pathogenic potential of these organisms, but also concerns about risks of spill-over between livestock, humans, and native wildlife.
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Affiliation(s)
- Martina Jelocnik
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Alyce Taylor-Brown
- Animal Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Christian O'Dea
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Susan Anstey
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Sankhya Bommana
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Nicole Masters
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Mohamad Katouli
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Cheryl Jenkins
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, Australia
| | - Adam Polkinghorne
- Animal Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
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Sánchez Romano J, Leijon M, Hagström Å, Jinnerot T, Rockström UK, Tryland M. Chlamydia pecorum Associated With an Outbreak of Infectious Keratoconjunctivitis in Semi-domesticated Reindeer in Sweden. Front Vet Sci 2019; 6:14. [PMID: 30805351 PMCID: PMC6370630 DOI: 10.3389/fvets.2019.00014] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/16/2019] [Indexed: 11/13/2022] Open
Abstract
Infectious keratoconjunctivitis (IKC), the most common ocular disease in ruminants worldwide, has affected semi-domesticated Eurasian reindeer (Rangifer tarandus tarandus) for over 100 years, both as individual cases and in outbreaks affecting tens to hundreds of animals. Recurrent IKC outbreaks have been affecting a semi-domesticated reindeer herd in Östra Kikkejaure (Norrbotten county, Sweden) from 2014. The latest episode of these recurrent outbreaks, in winter 2016/2017, was investigated in this study. Clinical findings were in line with previous reports of IKC in semi-domesticated reindeer and the clinical signs displayed by the affected animals (n = 30) included increased lacrimation, follicular conjunctivitis, purulent secretions around the affected eyes and corneal edema. Laboratory analyses of the samples revealed the presence of Chlamydiaceae in most samples obtained from the clinically affected animals (98.3%, n = 60), but also a high seroprevalence of cervid herpesvirus 2 (CvHV2) antibodies (56.6%, n = 53). Moraxella bovoculi was isolated from nine IKC-affected animals during the outbreak (45.0%, n = 20). All affected animals were treated with long-acting antibiotics and recovered from the disease, testing negative for the presence of Chlamydiaceae DNA by PCR 16 days and 3 months after the initial treatment. For the first time, Chlamydia pecorum was identified in semi-domesticated reindeer, and the involvement of Chlamydiaceae in a clinical outbreak of IKC is reported. The CvHV2 seroprevalence (56.6%) and the data obtained from a previous outbreak in 2014 also suggest the involvement of the reindeer alphaherpesvirus in the recurrent outbreaks.
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Affiliation(s)
- Javier Sánchez Romano
- Arctic Infection Biology, Department of Arctic and Marine Biology, UiT Arctic University of Norway, Tromsø, Norway
| | - Mikael Leijon
- Department of Microbiology, National Veterinary Institute, Uppsala, Sweden
| | - Åsa Hagström
- Department of Microbiology, National Veterinary Institute, Uppsala, Sweden
| | - Tomas Jinnerot
- Department of Microbiology, National Veterinary Institute, Uppsala, Sweden
| | | | - Morten Tryland
- Arctic Infection Biology, Department of Arctic and Marine Biology, UiT Arctic University of Norway, Tromsø, Norway
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Abstract
Developed two decades ago as a molecular method to provide definite characterization of a bacterial isolate, Multilocus Sequence Typing (MLST) is today globally adopted as a universal fine-detailed molecular typing tool and has been applied to numerous pathogenic and nonpathogenic bacterial as well eukaryotic organisms. MLST utilizes DNA sequence of several conserved housekeeping (HK) genes which are assigned an allelic number, which then collectively constitute an allelic profile or sequence type (ST), a "molecular barcode" of the interrogated bacterial strain or a eukaryotic organism. Here, we describe the principles and molecular approaches for generating MLST data for an analysis of a bacteria in the order Chlamydiales, using a Chlamydia pecorum-specific MLST scheme as an example.
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Jelocnik M, Islam MM, Madden D, Jenkins C, Branley J, Carver S, Polkinghorne A. Development and evaluation of rapid novel isothermal amplification assays for important veterinary pathogens: Chlamydia psittaci and Chlamydia pecorum. PeerJ 2017; 5:e3799. [PMID: 28929022 PMCID: PMC5592900 DOI: 10.7717/peerj.3799] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/22/2017] [Indexed: 11/20/2022] Open
Abstract
Background Chlamydia psittaci and Chlamydia pecorum are important veterinary pathogens, with the former also being responsible for zoonoses, and the latter adversely affecting koala populations in Australia and livestock globally. The rapid detection of these organisms is still challenging, particularly at the point-of-care (POC). In the present study, we developed and evaluated rapid, sensitive and robust C. psittaci-specific and C. pecorum-specific Loop Mediated Isothermal Amplification (LAMP) assays for detection of these pathogens. Methods and Materials The LAMP assays, performed in a Genie III real-time fluorometer, targeted a 263 bp region of the C. psittaci-specific Cps_0607 gene or a 209 bp region of a C. pecorum-specific conserved gene CpecG_0573, and were evaluated using a range of samples previously screened using species-specific quantitative PCRs (qPCRs). Species-specificity for C. psittaci and C. pecorum LAMP targets was tested against DNA samples from related chlamydial species and a range of other bacteria. In order to evaluate pathogen detection in clinical samples, C. psittaci LAMP was evaluated using a total of 26 DNA extracts from clinical samples from equine and avian hosts, while for C. pecorum LAMP, we tested a total of 63 DNA extracts from clinical samples from koala, sheep and cattle hosts. A subset of 36 C. pecorum samples was also tested in a thermal cycler (instead of a real-time fluorometer) using newly developed LAMP and results were determined as an end point detection. We also evaluated rapid swab processing (without DNA extraction) to assess the robustness of these assays. Results Both LAMP assays were demonstrated to species-specific, highly reproducible and to be able to detect as little as 10 genome copy number/reaction, with a mean amplification time of 14 and 24 min for C. psittaci and C. pecorum, respectively. When testing clinical samples, the overall congruence between the newly developed LAMP assays and qPCR was 92.3% for C. psittaci (91.7% sensitivity and 92.9% specificity); and 84.1% for C. pecorum (90.6% sensitivity and 77.4% specificity). For a subset of 36 C. pecorum samples tested in a thermal cycler using newly developed LAMP, we observed 34/36 (94.4%) samples result being congruent between LAMP performed in fluorometer and in thermal cycler. Rapid swab processing method evaluated in this study also allows for chlamydial DNA detection using LAMP. Discussion In this study, we describe the development of novel, rapid and robust C. psittaci-specific and C. pecorum-specific LAMP assays that are able to detect these bacteria in clinical samples in either the laboratory or POC settings. With further development and a focus on the preparation of these assays at the POC, it is anticipated that both tests may fill an important niche in the repertoire of ancillary diagnostic tools available to clinicians.
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Affiliation(s)
- Martina Jelocnik
- Centre for Animal Health Innovation, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Md Mominul Islam
- Centre for Animal Health Innovation, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Danielle Madden
- Centre for Animal Health Innovation, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Cheryl Jenkins
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, Australia
| | - James Branley
- Nepean Hospital, Penrith, New South Wales, Australia
| | - Scott Carver
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Adam Polkinghorne
- Centre for Animal Health Innovation, University of the Sunshine Coast, Maroochydore, Queensland, Australia
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Jelocnik M, Polkinghorne A. Chlamydia pecorum: successful pathogen of koalas or Australian livestock? MICROBIOLOGY AUSTRALIA 2017. [DOI: 10.1071/ma17042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In Australia, the obligate intracellular bacterium Chlamydia pecorum is best known as the notorious koala pathogen that causes debilitating ocular and urogenital tract disease. While globally published data suggests that this species is essentially ubiquitous in livestock, little is known about the epidemiology of livestock C. pecorum infections here in Australia. My research is focused on investigating the genetic diversity and transmission patterns of C. pecorum, and why it causes disease. Using our newly developed C. pecorum-specific molecular epidemiology typing scheme we provided the first epidemiological data on infections in sheep and cattle in Australia, identifying strains associated with a range of diseases in livestock, and uncovering an unexpected level of diversity for this pathogen. Most importantly, we observed that the same strain can infect koala and sheep, indicating on ongoing cross-host transmission and ‘spill-over' risks to wildlife. Further, by dissecting koala, sheep, cattle and pig C. pecorum strains genomes, we have also identified novel virulence-associated factors that could be explored as vaccine candidates for both livestock and koala infections.
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Jelocnik M, Bachmann NL, Seth-Smith H, Thomson NR, Timms P, Polkinghorne AM. Molecular characterisation of the Chlamydia pecorum plasmid from porcine, ovine, bovine, and koala strains indicates plasmid-strain co-evolution. PeerJ 2016; 4:e1661. [PMID: 26870613 PMCID: PMC4748734 DOI: 10.7717/peerj.1661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/14/2016] [Indexed: 01/07/2023] Open
Abstract
Background. Highly stable, evolutionarily conserved, small, non-integrative plasmids are commonly found in members of the Chlamydiaceae and, in some species, these plasmids have been strongly linked to virulence. To date, evidence for such a plasmid in Chlamydia pecorum has been ambiguous. In a recent comparative genomic study of porcine, ovine, bovine, and koala C. pecorum isolates, we identified plasmids (pCpec) in a pig and three koala strains, respectively. Screening of further porcine, ovine, bovine, and koala C. pecorum isolates for pCpec showed that pCpec is common, but not ubiquitous in C. pecorum from all of the infected hosts. Methods. We used a combination of (i) bioinformatic mining of previously sequenced C. pecorum genome data sets and (ii) pCpec PCR-amplicon sequencing to characterise a further 17 novel pCpecs in C. pecorum isolates obtained from livestock, including pigs, sheep, and cattle, as well as those from koala. Results and Discussion. This analysis revealed that pCpec is conserved with all eight coding domain sequences (CDSs) present in isolates from each of the hosts studied. Sequence alignments revealed that the 21 pCpecs show 99% nucleotide sequence identity, with 83 single nucleotide polymorphisms (SNPs) shown to differentiate all of the plasmids analysed in this study. SNPs were found to be mostly synonymous and were distributed evenly across all eight pCpec CDSs as well as in the intergenic regions. Although conserved, analyses of the 21 pCpec sequences resolved plasmids into 12 distinct genotypes, with five shared between pCpecs from different isolates, and the remaining seven genotypes being unique to a single pCpec. Phylogenetic analysis revealed congruency and co-evolution of pCpecs with their cognate chromosome, further supporting polyphyletic origin of the koala C. pecorum. This study provides further understanding of the complex epidemiology of this pathogen in livestock and koala hosts and paves the way for studies to evaluate the function of this putative C. pecorum virulence factor.
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Affiliation(s)
- Martina Jelocnik
- Centre for Animal Health Innovation, University of the Sunshine Coast , Sippy Downs, Queensland , Australia
| | - Nathan L Bachmann
- Centre for Animal Health Innovation, University of the Sunshine Coast , Sippy Downs, Queensland , Australia
| | - Helena Seth-Smith
- Functional Genomics Center Zurich, University of Zurich , Zurich , Switzerland
| | - Nicholas R Thomson
- Infection Genomics, The Wellcome Trust Sanger Institute , Cambridge , United Kingdom
| | - Peter Timms
- Centre for Animal Health Innovation, University of the Sunshine Coast , Sippy Downs, Queensland , Australia
| | - Adam M Polkinghorne
- Centre for Animal Health Innovation, University of the Sunshine Coast , Sippy Downs, Queensland , Australia
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Jelocnik M, Bachmann NL, Kaltenboeck B, Waugh C, Woolford L, Speight KN, Gillett A, Higgins DP, Flanagan C, Myers GSA, Timms P, Polkinghorne A. Genetic diversity in the plasticity zone and the presence of the chlamydial plasmid differentiates Chlamydia pecorum strains from pigs, sheep, cattle, and koalas. BMC Genomics 2015; 16:893. [PMID: 26531162 PMCID: PMC4632680 DOI: 10.1186/s12864-015-2053-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 10/08/2015] [Indexed: 12/22/2022] Open
Abstract
Background Chlamydia pecorum is a globally recognised pathogen of livestock and koalas. To date, comparative genomics of C. pecorum strains from sheep, cattle and koalas has revealed that only single nucleotide polymorphisms (SNPs) and a limited number of pseudogenes appear to contribute to the genetic diversity of this pathogen. No chlamydial plasmid has been detected in these strains despite its ubiquitous presence in almost all other chlamydial species. Genomic analyses have not previously included C. pecorum from porcine hosts. We sequenced the genome of three C. pecorum isolates from pigs with differing pathologies in order to re-evaluate the genetic differences and to update the phylogenetic relationships between C. pecorum from each of the hosts. Methods Whole genome sequences for the three porcine C. pecorum isolates (L1, L17 and L71) were acquired using C. pecorum-specific sequence capture probes with culture-independent methods, and assembled in CLC Genomics Workbench. The pairwise comparative genomic analyses of 16 pig, sheep, cattle and koala C. pecorum genomes were performed using several bioinformatics platforms, while the phylogenetic analyses of the core C. pecorum genomes were performed with predicted recombination regions removed. Following the detection of a C. pecorum plasmid, a newly developed C. pecorum-specific plasmid PCR screening assay was used to evaluate the plasmid distribution in 227 C. pecorum samples from pig, sheep, cattle and koala hosts. Results Three porcine C. pecorum genomes were sequenced using C. pecorum-specific sequence capture probes with culture-independent methods. Comparative genomics of the newly sequenced porcine C. pecorum genomes revealed an increased average number of SNP differences (~11 500) between porcine and sheep, cattle, and koala C. pecorum strains, compared to previous C. pecorum genome analyses. We also identified a third copy of the chlamydial cytotoxin gene, found only in porcine C. pecorum isolates. Phylogenetic analyses clustered porcine isolates into a distinct clade, highlighting the polyphyletic origin of C. pecorum in livestock. Most surprising, we also discovered a plasmid in the porcine C. pecorum genome. Using this novel C. pecorum plasmid (pCpec) sequence, a) we developed a pCpec screening assay to evaluate the plasmid distribution in C. pecorum from different hosts; and b) to characterise the pCpec sequences from available previously sequenced C. pecorum genome data. pCpec screening showed that the pCpec is common in all hosts of C. pecorum, however not all C. pecorum strains carry pCpec. Conclusions This study provides further insight into the complexity of C. pecorum epidemiology and novel genomic regions that may be linked to host specificity. C. pecorum plasmid characterisation may aid in improving our understanding of C. pecorum pathogenesis across the variety of host species this animal pathogen infects. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2053-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martina Jelocnik
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4558, Australia
| | - Nathan L Bachmann
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4558, Australia
| | | | - Courtney Waugh
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4558, Australia
| | - Lucy Woolford
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, South Australia, 5371, Australia
| | - K Natasha Speight
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, South Australia, 5371, Australia
| | - Amber Gillett
- Australia Zoo Wildlife Hospital, Beerwah, QLD, 4519, Australia
| | - Damien P Higgins
- Faculty of Veterinary Science, The University of Sydney, New South Wales, 2006, Australia
| | - Cheyne Flanagan
- Port Macquarie Koala Hospital, Port Macquarie, NSW, 2444, Australia
| | - Garry S A Myers
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Peter Timms
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4558, Australia
| | - Adam Polkinghorne
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4558, Australia.
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