Preliminary phylogenetic identification of virulent Chlamydophila pecorum strains

Mohamad, Khalil Yousef; Roche, Sylvie; Myers, Garry; Bavoil, Patrik M.; Laroucau, Karine; Magnino, Simone; Laurent, Sylvie; Rasschaert, Denis; Rodolakis, Annie

doi:10.1016/j.meegid.2008.06.009

Cited by 36 publications

(32 citation statements)

References 48 publications

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“…These latter isolates had 100% sequence identity to other C. pecorum SBE isolates (E58, NSW/Bov/SBE and SBE), with a clear separation from isolates detected in bovine faeces. This observation of a phylogenetic distinction between SBE and faecal isolates has been previously described using an alternative multi-locus virulence typing scheme [16]. This is the first study to describe this observation in a single animal, however, further reinforcing that bacterial genetic differences may indeed be associated with differences in tissue tropism/pathogenicity [22].…”

Section: Case Presentationsupporting

confidence: 60%

“…Molecular markers have been used to discriminate between livestock C. pecorum strains with different disease presentations [15,16]. Yousef Mohamad et al (2008), using Multi Virulence Locus Sequence Typing (MVLST) of C. pecorum strains isolated from a range of hosts and disease states, showed significant genetic diversity within these strains and some evidence of separation of livestock C. pecorum strains associated with morbidity from those isolated from the faeces of healthy cows.…”

Section: Introductionmentioning

confidence: 99%

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Molecular and pathological insights into Chlamydia pecorum-associated sporadic bovine encephalomyelitis (SBE) in Western Australia

Jelocnik

Forshaw²,

Cotter³

et al. 2014

BMC Vet Res

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BackgroundDespite its global recognition as a ruminant pathogen, cases of Chlamydia pecorum infection in Australian livestock are poorly documented. In this report, a C. pecorum specific Multi Locus Sequence Analysis scheme was used to characterise the C. pecorum strains implicated in two cases of sporadic bovine encephalomyelitis confirmed by necropsy, histopathology and immunohistochemistry. This report provides the first molecular evidence for the presence of mixed infections of C. pecorum strains in Australian cattle.Case presentationAffected animals were two markedly depressed, dehydrated and blind calves, 12 and 16 weeks old. The calves were euthanized and necropsied. In one calf, a severe fibrinous polyserositis was noted with excess joint fluid in all joints whereas in the other, no significant lesions were seen. No gross abnormalities were noted in the brain of either calf. Histopathological lesions seen in both calves included: multifocal, severe, subacute meningoencephalitis with vasculitis, fibrinocellular thrombosis and malacia; diffuse, mild, acute interstitial pneumonia; and diffuse, subacute epicarditis, severe in the calf with gross serositis. Immunohistochemical labelling of chlamydial antigen in brain, spleen and lung from the two affected calves and brain from two archived cases, localised the antigen to the cytoplasm of endothelium, mesothelium and macrophages. C. pecorum specific qPCR, showed dissemination of the pathogen to multiple organs. Phylogenetic comparisons with other C. pecorum bovine strains from Australia, Europe and the USA revealed the presence of two genetically distinct sequence types (ST). The predominant ST detected in the brain, heart, lung and liver of both calves was identical to the C. pecorum ST previously described in cases of SBE. A second ST detected in an ileal tissue sample from one of the calves, clustered with previously typed faecal bovine isolates.ConclusionThis report provides the first data to suggest that identical C. pecorum STs may be associated with SBE in geographically separated countries and that these may be distinct from those found in the gastrointestinal tract. This report provides a platform for further investigations into SBE and for understanding the genetic relationships that exist between C. pecorum strains detected in association with other infectious diseases in livestock.

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Section: Case Presentationsupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Molecular and pathological insights into Chlamydia pecorum-associated sporadic bovine encephalomyelitis (SBE) in Western Australia

Jelocnik

Forshaw²,

Cotter³

et al. 2014

BMC Vet Res

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“…In earlier investigations, we found virulence-associated genetic differences among 19 C. pecorum strains by identifying different motifs of the variant coding tandem repeats (CTR) in incA of isolates from sick versus healthy ruminants [24]. By determining lower numbers of repetitions of the CTR in the hypothetical ORF663 in highly virulent C. pecorum strains than in low-virulence isolates, we further identified virulence-associated genetic polymorphisms of C. pecorum [25]. In addition, 6 out of 8 strains from diseased ruminants clustered to a single ompA sequence group [25].…”

Section: Introductionmentioning

confidence: 95%

“…By determining lower numbers of repetitions of the CTR in the hypothetical ORF663 in highly virulent C. pecorum strains than in low-virulence isolates, we further identified virulence-associated genetic polymorphisms of C. pecorum [25]. In addition, 6 out of 8 strains from diseased ruminants clustered to a single ompA sequence group [25].…”

Section: Introductionmentioning

confidence: 98%

Host Adaptation of Chlamydia pecorum towards Low Virulence Evident in Co-Evolution of the ompA, incA, and ORF663 Loci

et al. 2014

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Chlamydia (C.) pecorum, an obligate intracellular bacterium, may cause severe diseases in ruminants, swine and koalas, although asymptomatic infections are the norm. Recently, we identified genetic polymorphisms in the ompA, incA and ORF663 genes that potentially differentiate between high-virulence C. pecorum isolates from diseased animals and low-virulence isolates from asymptomatic animals. Here, we expand these findings by including additional ruminant, swine, and koala strains. Coding tandem repeats (CTRs) at the incA locus encoded a variable number of repeats of APA or AGA amino acid motifs. Addition of any non-APA/AGA repeat motif, such as APEVPA, APAVPA, APE, or APAPE, associated with low virulence (P<10−4), as did a high number of amino acids in all incA CTRs (P = 0.0028). In ORF663, high numbers of 15-mer CTRs correlated with low virulence (P = 0.0001). Correction for ompA phylogram position in ORF663 and incA abolished the correlation between genetic changes and virulence, demonstrating co-evolution of ompA, incA, and ORF663 towards low virulence. Pairwise divergence of ompA, incA, and ORF663 among isolates from healthy animals was significantly higher than among strains isolated from diseased animals (P≤10−5), confirming the longer evolutionary path traversed by low-virulence strains. All three markers combined identified 43 unique strains and 4 pairs of identical strains among all 57 isolates tested, demonstrating the suitability of these markers for epidemiological investigations.

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“…Numerous serovars of C. suis (5), C. pecorum (6,7), C. trachomatis (8,9), and C. psittaci (10)(11)(12) have been reported. Different serovars of a species cause multiple diseases in a single host, e.g., serovars of C. trachomatis cause trachoma, infections of reproductive organs, or lymphogranuloma venereum in humans (1).…”

mentioning

confidence: 99%

Defining Species-Specific Immunodominant B Cell Epitopes for Molecular Serology of Chlamydia Species

Rahman

Chowdhury

Poudel

et al. 2015

Clin. Vaccine Immunol.

107

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bUrgently needed species-specific enzyme-linked immunosorbent assays (ELISAs) for the detection of antibodies against Chlamydia spp. have been elusive due to high cross-reactivity of chlamydial antigens. To identify Chlamydia species-specific B cell epitopes for such assays, we ranked the potential epitopes of immunodominant chlamydial proteins that are polymorphic among all Chlamydia species. High-scoring peptides were synthesized with N-terminal biotin, followed by a serine-glycine-serine-glycine spacer, immobilized onto streptavidin-coated microtiter plates, and tested with mono-specific mouse hyperimmune sera against each Chlamydia species in chemiluminescent ELISAs. For each of nine Chlamydia species, three to nine dominant polymorphic B cell epitope regions were identified on OmpA, CT618, PmpD, IncA, CT529, CT442, IncG, Omp2, TarP, and IncE proteins. Peptides corresponding to 16-to 40-amino-acid species-specific sequences of these epitopes reacted highly and with absolute specificity with homologous, but not heterologous, Chlamydia monospecies-specific sera. Host-independent reactivity of such epitopes was confirmed by testing of six C. pecorum-specific peptides from five proteins with C. pecorum-reactive sera from cattle, the natural host of C. pecorum. The probability of cross-reactivity of peptide antigens from closely related chlamydial species or strains correlated with percent sequence identity and declined to zero at <50% sequence identity. Thus, phylograms of B cell epitope regions predict the specificity of peptide antigens for rational use in the genus-, species-, or serovar-specific molecular serology of Chlamydia spp. We anticipate that these peptide antigens will improve chlamydial serology by providing easily accessible assays to nonspecialist laboratories. Our approach also lends itself to the identification of relevant epitopes of other microbial pathogens.

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Preliminary phylogenetic identification of virulent Chlamydophila pecorum strains

Cited by 36 publications

References 48 publications

Molecular and pathological insights into Chlamydia pecorum-associated sporadic bovine encephalomyelitis (SBE) in Western Australia

Molecular and pathological insights into Chlamydia pecorum-associated sporadic bovine encephalomyelitis (SBE) in Western Australia

Host Adaptation of Chlamydia pecorum towards Low Virulence Evident in Co-Evolution of the ompA, incA, and ORF663 Loci

Defining Species-Specific Immunodominant B Cell Epitopes for Molecular Serology of Chlamydia Species

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