Emergence of Staphylococcus aureus carrying multiple drug resistance genes on a plasmid encoding exfoliative toxin B.
Antimicrob Agents Chemother
; 57(12): 6131-40, 2013 Dec.
Article
in En
| MEDLINE
| ID: mdl-24080652
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 (â¼30 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(2â³)], 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(2â³) 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(2â³) 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(2â³) 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Plasmids
/
Staphylococcus aureus
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Drug Resistance, Multiple, Bacterial
/
Exfoliatins
Type of study:
Observational_studies
/
Risk_factors_studies
Limits:
Humans
Country/Region as subject:
Asia
Language:
En
Journal:
Antimicrob Agents Chemother
Year:
2013
Document type:
Article
Affiliation country:
Country of publication: