NEW EXFOLIATIVE TOXIN-ENCODING MOBILE GENETIC ELEMENTS REVEALED IN STAPHYLOCOCCUS AUREUS
| Authors | |
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| Year of publication | 2018 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Background: Exfoliative toxins A (ETA) and B (ETB), the major cause of staphylococcal epidermolytic diseases, are encoded by tempered bacteriophages and plasmids playing a crucial role in pathogenic strains origin. Objectives: Characterization and comparative genomic analysis of previously undescribed eta-positive bacteriophages (ETA-phages) and etb-positive plasmids (ETB-plasmids) isolated from clinical strains. Methods: Bioinformatics, lysogenization, PCR, PFGE, SDS-PAGE, LC-MS/MS. Results: The phages studied represent novel types of phages belonging to Siphoviridae family. Comparison with already described phages revealed, that their genomes contain sequences gained by recombination, and show numerous differences that manifested in virion structural proteins. Using the phages, we accomplished positive lysogenic conversion of non-toxigenic S. aureus strain to highly effective producer of ETA. ETB-plasmids isolated from strains of clonal complex CC121 share a large part of DNA sequence including typical virulence genes. On the other hand, they contain variable regions influencing bacterial pathogenicity. A novel ETB-plasmid showing minimal sequence homology with others was described. It represents a novel lineage of ETB-plasmids not associated with CC121 strains, and carrying conjugation genes as well as new variants of virulence genes. A multiplex PCR assay has been designed to distinguish all the types of ETB-plasmids described. Conclusions. This study presents a complex analysis of novel exfoliative toxin-encoding elements of Staphylococcus aureus with a crucial impact on pathogenicity of clinical strains. This work was supported by Grant from Ministry of Agriculture of the Czech Republic (QJ1510216), AdmireVet CZ.1.05/2.1.00/01.0006–ED0006/01/01, and from Masaryk University MUNI/A/0824/2017. |
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