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Published on: September 5, 2013
Integration analysis of pSK41 in the chromosome of a methicillin-resistant Staphylococcus aureus K-1
Cathal J McElgunn1, M Zahurul, A Bhuyian
1Institute of Pharmaceutical Sciences, Faculty of Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan.
Abstract:
An integrate of pUB110 carrying aadD and blmS genes conferring resistance to 4'-OH containing aminoglycosides and bleomycin, respectively, is found in the Staphylococcal conjugative plasmid pSK41 and in the mec chromosomal region. In this study, we found an integrated copy of pSK41 in the chromosome of an arbekacin-resistant MRSA strain, K-1, clinically isolated in Japan. This is the first report of the chromosomal integration of this large plasmid in MRSA. Analysis of the nucleotide sequence and restriction map revealed a complete homology of the blmS-containing region of the integrate to wild type pSK41, except for the deletion of aadD and a part of the repU gene. In addition, we have discovered an insertion of IS1182 within the pSK41 integrate. Pulse-field gel electrophoresis-Southern analysis showed that the integration occurred outside the mec region. We also found that deletion of aadD resulted in an aberration of blmS transcription.
Insights
This study reports the first chromosomal integration of the large Staphylococcus plasmid pSK41 in methicillin-resistant Staphylococcus aureus (MRSA). The integration in a Japanese MRSA strain K-1 involved deletions and an IS1182 insertion, affecting antibiotic resistance gene transcription.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- The Staphylococcal conjugative plasmid pSK41 contains aadD and blmS genes, conferring resistance to specific aminoglycosides and bleomycin.
- Chromosomal integration of pSK41 has been observed in the mec region and within the pUB110 plasmid.
Purpose of the Study:
- To investigate the chromosomal integration of the pSK41 plasmid in a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA).
- To characterize the genetic modifications within the integrated pSK41 plasmid and their impact on gene expression.
Main Methods:
- Nucleotide sequencing and restriction mapping of the integrated pSK41.
- Pulse-field gel electrophoresis-Southern analysis to determine integration site.
- Analysis of blmS gene transcription.
Main Results:
- Identified chromosomal integration of pSK41 in an arbekacin-resistant MRSA strain (K-1) from Japan.
- The integrated pSK41 showed homology to wild-type pSK41, with deletions in aadD and repU, and an IS1182 insertion.
- Integration occurred outside the mec region, and aadD deletion affected blmS transcription.
Conclusions:
- This is the first report of pSK41 chromosomal integration in MRSA.
- Genetic alterations in the integrated pSK41, including IS1182 insertion and gene deletions, can occur.
- The deletion of aadD influences blmS transcription, potentially impacting antibiotic resistance profiles.
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