Analysis of new types of exfoliative toxin B-encoding plasmids carried by impetigo strains of Staphylococcus aureus
| Authors | |
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| Year of publication | 2017 |
| Type | Article in Proceedings |
| Conference | The Biomania Student Scientific Meeting 2017 |
| MU Faculty or unit | |
| Citation | |
| Field | Genetics and molecular biology |
| Keywords | ETB plasmid; exfoliative toxin B; phylogeny; genome analysis |
| Description | Bullous impetigo and staphylococcal scalded skin syndrome are diseases caused by Staphylococcus aureus strains producing exfoliative toxins A and/or B. These toxins are encoded by prophages and plasmids, respectively. We analyzed a set of exfoliative toxin B-encoding plasmids (ETB plasmids) isolated from the impetigo strains implicated in outbreaks of epidermolytic diseases in several Czech maternity hospitals. Restriction endonuclease analysis, DNA sequencing and PCR typing, as well as bioinformatics tools were used for characterization and comparison of the plasmids. Most of them, similar to the archetypal plasmid pETBTY4, formed the main lineage. Sharing a same core sequence, they differed from each other by extra DNA content. The plasmids of this lineage were carried by strains of clonal complex CC121, often along with the prophages encoding exfoliative toxin A. From a prophageless strain, a novel plasmid carrying gene cluster for conjugation and new variants of virulence genes was isolated. It was characterized in detail and could be regarded as a source of a new lineage of ETB plasmids. Based on our findings, we have designed a helpful assay, which enables the precise detection of the novel gene variant for exfoliative toxin B, and facilitates the identification of all described ETB plasmid types. Identified sequence variations enable us to reveal the diversity of ETB plasmids, which are the substantial source of virulence factors in the population of impetigo S. aureus strains. |
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