Complete Genome Sequence of Exfoliative Toxin-Producing Staphylococcus aureus Strain MSSA_SSSS_01, Obtained from a Case of Staphylococcal Scalded-Skin Syndrome.
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ABSTRACT:
SUBMITTER: Cella E
PROVIDER: S-EPMC7883837 | biostudies-literature | 2021 Feb
REPOSITORIES: biostudies-literature
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Complete Genome Sequence of Exfoliative Toxin-Producing Staphylococcus aureus Strain MSSA_SSSS_01, Obtained from a Case of Staphylococcal Scalded-Skin Syndrome.
Cella Eleonora E David Michael Z MZ Jubair Mohammad M Baines Sarah L SL Pegues David A DA Azarian Taj T
Microbiology resource announcements 20210211 6
Here, we announce the complete genome sequence of an exfoliative toxin-producing strain of <i>Staphylococcus aureus</i> sequence type 582 (ST582), isolated from a case of staphylococcal scalded-skin syndrome. The genome consists of a single circularized unitig with a total length of 2,792,190 bp carrying 2,699 genes. The genome is the basis for future epidemiological and genomic studies. ...[more]
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| S-EPMC98872 | biostudies-literature
Project description:We report the complete nucleotide sequence and analysis of pETBTY825, a Staphylococcus aureus TY825 plasmid encoding exfoliative toxin B (ETB). S. aureus TY825 is a clinical isolate obtained from an impetigo patient in 2002. The size of pETBTY825, 60.6 kbp, was unexpectedly larger than that of the archetype pETBTY4 (?30 kbp). Genomic comparison of the plasmids shows that pETBTY825 has the archetype pETBTY4 as the backbone and has a single large extra DNA region of 22.4 kbp. The extra DNA region contains genes for resistance to aminoglycoside [aac(6')/aph(2?)], macrolide (msrA), and penicillin (blaZ). A plasmid deletion experiment indicated that these three resistance elements were functionally active. We retrospectively examined the resistance profile of the clinical ETB-producing S. aureus strains isolated in 1977 to 2007 using a MIC determination with gentamicin (GM), arbekacin (ABK), and erythromycin (EM) and by PCR analyses for aac(6')/aph(2?) and msrA using purified plasmid preparations. The ETB-producing S. aureus strains began to display high resistance to GM, which was parallel with the detection of aac(6')/aph(2?) and mecA, after 1990. Conversely, there was no significant change in the ABK MIC during the testing period, although it had a tendency to slightly increase. After 2001, isolates resistant to EM significantly increased; however, msrA was hardly detected in ETB-producing S. aureus strains, and only five isolates were positive for both aac(6')/aph(2?) and msrA. In this study, we report the emergence of a fusion plasmid carrying the toxin gene etb and drug resistance genes. Prevalence of the pETBTY825 carrier may further increase the clinical threat, since ETB-producing S. aureus is closely related to more severe impetigo or staphylococcal scalded-skin syndrome (SSSS), which requires a general antimicrobial treatment.
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Project description:Staphylococcal scalded-skin syndrome is an exfoliative dermatitis characterized by the separation of the epidermis at the stratum granulosum. This disruption is mediated by one of two Staphylococcus aureus exotoxins, exfoliative toxins A and B (ETA and ETB). Both ETA and ETB have been reported to be bacterial superantigens. A controversy exists, however, as other data indicate that these exotoxins are not superantigens. Here we demonstrate that recombinant exfoliative toxins produced in Escherichia coli do not act as T-cell mitogens and thus are not bacterial superantigens. These data fit the clinical profile of the disease, which is not associated with the classic symptoms of a superantigen-mediated syndrome.
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Project description:We identified a novel pathogenicity island in Staphylococcus aureus which contains open reading frames (ORFs) similar to the exfoliative toxin (ET) gene, glutamyl endopeptidase gene, and edin-B gene in tandem and the phage resistance gene, flanked by hsdM, hsdS (restriction and modification system), and IS256. The protein encoded by the ET-like gene showed 40, 59, and 68% amino acid sequence identities with exfoliative toxin A (ETA), exfoliative toxin B (ETB), and Staphylococcus hyicus ETB (ShETB), respectively. When injected into neonatal mice, the recombinant protein derived from the ET-like gene induced exfoliation of the skin with loss of cell-to-cell adhesion in the upper part of the epidermis as observed in histological examinations, just as was found in neonatal mice injected with ETA or ETB. Western blot analysis indicated that the recombinant protein is serologically distinct from ETA and ETB. Therefore, the product encoded by this new ORF is a new ET member produced by S. aureus and is termed ETD. ETD did not induce blisters in 1-day-old chickens. In the skins of mice injected with ETD, cell surface staining of desmoglein 1 (Dsg1), a cadherin type cell-to-cell adhesion molecule in desmosomes, was abolished without affecting that of desmoglein 3 (Dsg3). Furthermore, in vitro incubation of the recombinant extracellular domains of Dsg1 and Dsg3 with the recombinant protein demonstrated that both mouse and human Dsg1, but not Dsg3, were directly cleaved in a dose-dependent manner. These results demonstrate that ETD and ETA induce blister formation by identical pathophysiological mechanisms. Clinical strains positive for edin-B were suggested to be clonally associated, and all edin-B-positive strains tested were positive for etd. Among 18 etd-positive strains, 12 produced ETD extracellularly. Interestingly, these strains are mainly isolated from other sources of infections and not from patients with bullous impetigo or staphylococcal scalded-skin syndrome. This strongly suggests that ETD might play a pathogenic role in a broader spectrum of bacterial infections than previously considered.
| S-EPMC128317 | biostudies-literature