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Vorimore F.,French Agency for Food Environmental and Occupational Health Safety Anses | Cavanna N.,French Agency for Food Environmental and Occupational Health Safety Anses | Vicari N.,National Reference Laboratory for Animal Chlamydioses | Magnino S.,National Reference Laboratory for Animal Chlamydioses | And 4 more authors.
Journal of Microbiological Methods | Year: 2012

We describe a novel high-resolution melt assay that clearly differentiates Chlamydia abortus live vaccine strain 1B from field C. abortus strains and field wild-type isolates based on previously described single nucleotide polymorphisms. This modern genotyping technique is inexpensive, easy to use, and less time-consuming than PCR-RFLP. © 2012 Elsevier B.V.. Source

Sait M.,Moredun Research Institute | Sait M.,University of Melbourne | Livingstone M.,Moredun Research Institute | Clark E.M.,Moredun Research Institute | And 8 more authors.
BMC Genomics | Year: 2014

Background: Chlamydia pecorum is the causative agent of a number of acute diseases, but most often causes persistent, subclinical infection in ruminants, swine and birds. In this study, the genome sequences of three C. pecorum strains isolated from the faeces of a sheep with inapparent enteric infection (strain W73), from the synovial fluid of a sheep with polyarthritis (strain P787) and from a cervical swab taken from a cow with metritis (strain PV3056/3) were determined using Illumina/Solexa and Roche 454 genome sequencing.Results: Gene order and synteny was almost identical between C. pecorum strains and C. psittaci. Differences between C. pecorum and other chlamydiae occurred at a number of loci, including the plasticity zone, which contained a MAC/perforin domain protein, two copies of a >3400 amino acid putative cytotoxin gene and four (PV3056/3) or five (P787 and W73) genes encoding phospholipase D. Chlamydia pecorum contains an almost intact tryptophan biosynthesis operon encoding trpABCDFR and has the ability to sequester kynurenine from its host, however it lacks the genes folA, folKP and folB required for folate metabolism found in other chlamydiae. A total of 15 polymorphic membrane proteins were identified, belonging to six pmp families. Strains possess an intact type III secretion system composed of 18 structural genes and accessory proteins, however a number of putative inc effector proteins widely distributed in chlamydiae are absent from C. pecorum. Two genes encoding the hypothetical protein ORF663 and IncA contain variable numbers of repeat sequences that could be associated with persistence of infection.Conclusions: Genome sequencing of three C. pecorum strains, originating from animals with different disease manifestations, has identified differences in ORF663 and pseudogene content between strains and has identified genes and metabolic traits that may influence intracellular survival, pathogenicity and evasion of the host immune system. © 2014 Sait et al.; licensee BioMed Central Ltd. Source

Laroucau K.,Unite Zoonoses Bacteriennes | Vorimore F.,Unite Zoonoses Bacteriennes | Sachse K.,Friedrich Loeffler Institute Federal Research Institute for Animal Health | Vretou E.,Hellenic Pasteur Institute | And 5 more authors.
Vaccine | Year: 2010

Comparative genomic analysis of a wild-type strain of the ovine pathogen . Chlamydophila abortus and its nitrosoguanidine-induced, temperature-sensitive and virulence-attenuated live vaccine derivative identified point mutations unique to the mutant (Burall et al. . [1]). Here, we evaluate the capacity of some of these mutations to either create or eliminate restriction sites using the wild-type strain . C. abortus S26/3 as a reference. Three of eight genomic sites with confirmed point mutations (CAB153, CAB636 and CAB648) were retained for analysis as each resulted in the loss of a restriction site in the genome sequence of the vaccine strain. PCR-restriction fragment length polymorphism analysis using restriction enzymes chosen to specifically target the three genomic sites was then applied to a large number of . C. abortus field isolates and reference strains. Our results indicate that the three mutations are uniquely present in the vaccine strain, and as such provide easy-to-use markers for the differential identification of the vaccine strain and wild-type isolates. © 2010 Elsevier Ltd. Source

Mohamad K.Y.,French National Institute for Agricultural Research | Mohamad K.Y.,Al-Furat University | Kaltenboeck B.,Auburn University | Rahman Kh.S.,Auburn University | And 3 more authors.
PLoS ONE | Year: 2014

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 lowvirulence 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. © 2014 Mohamad et al. Source

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