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Hebert L.,Dozule Laboratory for Equine Diseases | Moumen B.,French National Institute for Agricultural Research | Pons N.,French National Institute for Agricultural Research | Duquesne F.,Dozule Laboratory for Equine Diseases | And 6 more authors.
PLoS ONE | Year: 2012

The Taylorella genus comprises two species: Taylorella equigenitalis, which causes contagious equine metritis, and Taylorella asinigenitalis, a closely-related species mainly found in donkeys. We herein report on the first genome sequence of T. asinigenitalis, analyzing and comparing it with the recently-sequenced T. equigenitalis genome. The T. asinigenitalis genome contains a single circular chromosome of 1,638,559 bp with a 38.3% GC content and 1,534 coding sequences (CDS). While 212 CDSs were T. asinigenitalis-specific, 1,322 had orthologs in T. equigenitalis. Two hundred and thirty-four T. equigenitalis CDSs had no orthologs in T. asinigenitalis. Analysis of the basic nutrition metabolism of both Taylorella species showed that malate, glutamate and alpha-ketoglutarate may be their main carbon and energy sources. For both species, we identified four different secretion systems and several proteins potentially involved in binding and colonization of host cells, suggesting a strong potential for interaction with their host. T. equigenitalis seems better-equipped than T. asinigenitalis in terms of virulence since we identified numerous proteins potentially involved in pathogenicity, including hemagluttinin-related proteins, a type IV secretion system, TonB-dependent lactoferrin and transferrin receptors, and YadA and Hep_Hag domains containing proteins. This is the first molecular characterization of Taylorella genus members, and the first molecular identification of factors potentially involved in T. asinigenitalis and T. equigenitalis pathogenicity and host colonization. This study facilitates a genetic understanding of growth phenotypes, animal host preference and pathogenic capacity, paving the way for future functional investigations into this largely unknown genus. © 2012 Hébert et al. Source

Schlusselhuber M.,Dozule Laboratory for Equine Diseases | Guldbech K.,University of Georgia | Sevin C.,Laboratory for equine diseases | Leippe M.,University of Kiel | And 4 more authors.
FEMS Microbiology Letters | Year: 2014

The equine antimicrobial peptide eCATH1 previously has been shown to have in vitro activity against antibiotic-susceptible reference strains of Rhodococcus equi and common respiratory bacterial pathogens of foals. Interestingly, eCATH1 was also found to be effective in the treatment of R. equi infection induced in mice. The aim of this study was to assess the in vitro activity of eCATH1 against equine isolates of Gram-negative (Escherichia coli, Salmonella enterica, Klebsiella pneumoniae and Pseudomonas spp.) and Gram-positive (R. equi, Staphylococcus aureus) bacteria resistant to multiple classes of conventional antibiotics. A modified microdilution method was used to evaluate the minimum inhibitory concentrations (MICs) of the antimicrobial peptide. The study revealed that eCATH1 was active against all equine isolates of E. coli, S. enterica, K. pneumoniae, Pseudomonas spp. and R. equi tested, with MICs of 0.5-16 μg mL-1, but was not active against most isolates of S. aureus. In conclusion, the activity of the equine antimicrobial peptide eCATH1 appears to not be hampered by the antibiotic resistance of clinical isolates. Thus, the data suggest that eCATH1 could be useful, not only in the treatment of R. equi infections, but also of infections caused by multidrug-resistant Gram-negative pathogens. © 2013 Federation of European Microbiological Societies. Source

Bidaud P.,Dozule Laboratory for Equine Diseases | Hebert L.,Dozule Laboratory for Equine Diseases | Barbey C.,Dozule Laboratory for Equine Diseases | Barbey C.,CNRS Laboratory of Microbiology Signals and Microenvironment | And 6 more authors.
PLoS ONE | Year: 2012

Rhodococcus equi is one of the most widespread causes of disease in foals aged from 1 to 6 months. R. equi possesses antioxidant defense mechanisms to protect it from reactive oxygen metabolites such as hydrogen peroxide (H2O2) generated during the respiratory burst of phagocytic cells. These defense mechanisms include enzymes such as catalase, which detoxify hydrogen peroxide. Recently, an analysis of the R. equi 103 genome sequence revealed the presence of four potential catalase genes. We first constructed ΔkatA-, ΔkatB-, ΔkatC-and ΔkatD-deficient mutants to study the ability of R. equi to survive exposure to H2O2 in vitro and within mouse peritoneal macrophages. Results showed that ΔkatA and, to a lesser extent ΔkatC, were affected by 80 mM H2O2. Moreover, katA deletion seems to significantly affect the ability of R. equi to survive within murine macrophages. We finally investigated the expression of the four catalases in response to H2O2 assays with a real time PCR technique. Results showed that katA is overexpressed 367.9 times (±122.6) in response to exposure to 50 mM of H2O2 added in the stationary phase, and 3.11 times (±0.59) when treatment was administered in the exponential phase. In untreated bacteria, katB, katC and katD were overexpressed from 4.3 to 17.5 times in the stationary compared to the exponential phase. Taken together, our results show that KatA is the major catalase involved in the extreme H2O2 resistance capability of R. equi. © 2012 Bidaud et al. Source

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