Staphylococcus aureus je významný oportunní patogen a častý původce bakteriálních nozokomiálních nákaz.Patogenní vlastnosti této bakterie jsou často kódovány mobilními genetickými elementy, jako jsou např. plazmi-dy. Na plazmidu se nachází i gen etb pro exfoliativní toxin B (ETB), který je příčinou puchýřnatého onemocnění(bulózní impetigo), jehož generalizovaná a život ohrožující forma se označuje jako stafylokokový syndrom opařené kůže. U pěti etb-pozitivních plazmidů, izolovaných během let 1999–2015 z kmenů S. aureus pocházejícíchz českých nemocnic, byla provedena srovnávací sekvenční analýza. Bylo zjištěno, že velká většina z nich sdílírozsáhlou oblast sekvence DNA, která zahrnuje typické geny virulence, avšak obsahují i variabilní úseky umož-ňující jejich diferenciaci. Přestože se dosud předpokládalo, že jsou ETB plazmidy relativně uniformní, byl izolo-ván a popsán nový typ, který s ostatními ETB plazmidy vykazuje jen minimální sekvenční shodu. Nese navíc geny pro horizontální přenos konjugací a nové varianty genů pro faktory virulence včetně etb, čímž reprezentuje zcela novou linii plazmidů kódujících exfoliatin B.
Staphylococcus aureus is an important opportunistic pathogen and a common cause of bacterial nosocomialinfections. Pathogenic properties of this bacterium are often encoded by mobile genetic elements, such as plas-mids. Plasmids also carry the etb gene encoding exfoliative toxin B(ETB), which is the cause of ablistering disease(bullous impetigo)whose generalized and life-threatening form is known as staphylococcal scalded skin syn-drome. Comparative sequence analysis was conducted to study five etb-positive plasmids, isolated from S. aureusstrains from Czech hospitals between 1999 and 2015. They were found to share a large part of the DNA sequencecomprising typical virulence genes. However, they also contain variable fragments, which help us to differentiatebetween them. Although ETB plasmids were previously assumed to be relatively uniform, a new type showingminimal sequence similarity to other ETB plasmids was isolated and described. Moreover, it carries genes forhorizontal transfer by conjugation as well as new variants of genes for virulence factors, including etb, and assuch it represents a completely new lineage of exfoliative toxin B-encoding plasmids.
Exfoliative toxin B (ETB) encoded by some large plasmids plays a crucial role in epidermolytic diseases caused by Staphylococcus aureus. We have found as yet unknown types of etb gene-positive plasmids isolated from a set of impetigo strains implicated in outbreaks of pemphigus neonatorum in Czech maternity hospitals. Plasmids from the strains of clonal complex CC121 were related to archetypal plasmid pETBTY4. Sharing a 33-kb core sequence including virulence genes for ETB, EDIN C, and lantibiotics, they were assigned to a stand-alone lineage, named pETBTY4-based plasmids. Differing from each other in the content of variable DNA regions, they formed four sequence types. In addition to them, a novel unique plasmid pETB608 isolated from a strain of ST130 was described. Carrying conjugative cluster genes, as well as new variants of etb and edinA genes, pETB608 could be regarded as a source of a new lineage of ETB plasmids. We have designed a helpful detection assay, which facilitates the precise identification of the all described types of ETB plasmids.
- MeSH
- Bacterial Proteins genetics MeSH
- Bacteriocins genetics MeSH
- Dermotoxins genetics MeSH
- DNA, Bacterial genetics MeSH
- Exfoliatins genetics MeSH
- Phylogeny MeSH
- Impetigo epidemiology microbiology MeSH
- Humans MeSH
- Pemphigus epidemiology microbiology MeSH
- Plasmids genetics isolation & purification MeSH
- Whole Genome Sequencing MeSH
- Staphylococcus aureus classification genetics MeSH
- Virulence genetics MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Czech Republic epidemiology MeSH
